tazobactam against clinical isolates of Pseudomonas aeruginosa and Enterobacteriaceae recovered in Spanish medical centres: Results of the CENIT study

tazobactam against clinical isolates of Pseudomonas aeruginosa and Enterobacteriaceae recovered in Spanish medical centres: Results of the CENIT study

Accepted Manuscript Title: In vitro activity of ceftolozane/tazobactam against clinical isolates of Pseudomonas aeruginosa and Enterobacteriaceae reco...

326KB Sizes 0 Downloads 7 Views

Accepted Manuscript Title: In vitro activity of ceftolozane/tazobactam against clinical isolates of Pseudomonas aeruginosa and Enterobacteriaceae recovered in Spanish medical centres: results of the CENIT study Author: Marta Tato Mar´ıa Garc´ıa-Castillo Ana Moreno Bofarull Rafael Cant´on PII: DOI: Reference:

S0924-8579(15)00272-1 http://dx.doi.org/doi:10.1016/j.ijantimicag.2015.07.004 ANTAGE 4637

To appear in:

International

Received date: Revised date: Accepted date:

4-1-2015 19-6-2015 2-7-2015

Journal

of

Antimicrobial

Agents

Please cite this article as: Tato M, Garc´ia-Castillo M, Bofarull AM, Cant´on R, the CENIT Study Group, In vitro activity of ceftolozane/tazobactam against clinical isolates of Pseudomonas aeruginosa and Enterobacteriaceae recovered in Spanish medical centres: results of the CENIT study, International Journal of Antimicrobial Agents (2015), http://dx.doi.org/10.1016/j.ijantimicag.2015.07.004 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Highlights  Ceftolozane/tazobactam and ceftolozane were the most potent agents against

ip t

Pseudomonas aeruginosa, including multidrug-resistant strains.

isolates, including most ESBL- and AmpC-producers.

cr

 Ceftolozane/tazobactam shows good activity against most Enterobacteriaceae

Ac ce p

te

d

M

an

us

 Ceftolozane/tazobactam is inactive against carbapenemase-producing isolates.

1 Page 1 of 41

In vitro activity of ceftolozane/tazobactam against clinical isolates of Pseudomonas aeruginosa and Enterobacteriaceae recovered in

a,b

, María García-Castillo a,b, Ana Moreno Bofarull a,c, Rafael Cantón

*; the

us

CENIT Study Group

Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y

an

a

a,b,

cr

Marta Tato

ip t

Spanish medical centres: results of the CENIT study

Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain

Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud

M

b

Carlos III, Madrid, Spain

Ac ce p

Madrid, Spain

d

CIBER en Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III,

te

c

ARTICLE INFO Article history:

Received 4 January 2015 Accepted 2 July 2015

Keywords: Ceftolozane/tazobactam Gram-negative Surveillance 2 Page 2 of 41

Antimicrobial resistance

* Corresponding author. Present address: Servicio de Microbiología, Hospital

+34 913 368 330; +34 913 368 832.

Ac ce p

te

d

M

an

us

cr

E-mail address: [email protected] (R. Cantón).

ip t

Universitario Ramón y Cajal, Carretera de Colmenar km 9.1, 28034 Madrid, Spain. Tel.:

3 Page 3 of 41

ABSTRACT Ceftolozane/tazobactam is a novel antimicrobial agent with activity against Pseudomonas aeruginosa, including drug-resistant strains, and other Gram-negative

ip t

pathogens, including most extended-spectrum -lactamase (ESBL)-producing Enterobacteriaceae. The CENIT study evaluated the in vitro activity of

cr

ceftolozane/tazobactam and comparators against clinical isolates of P. aeruginosa (n =

us

500) and Enterobacteriaceae (n = 500) collected from patients with complicated intraabdominal, complicated urinary tract, lower respiratory tract or bloodstream infections in

an

10 medical centres in Spain (January–September 2013). Antimicrobial susceptibility was determined by the ISO broth microdilution method using commercial dry-form

M

panels and results were interpreted per EUCAST and CLSI guidelines and for

d

ceftolozane/tazobactam with FDA criteria. Ceftolozane/tazobactam and ceftolozane

te

alone were the most potent (MIC50/90, 0.5/4 mg/L) agents tested against all P. aeruginosa isolates. This advantage was maintained regardless of resistance

Ac ce p

phenotype, even against isolates resistant to multiple antibiotics. Ceftolozane/tazobactam demonstrated excellent overall activity (MIC50/90, 0.25/0.5 mg/L) against all 250 Escherichia coli isolates, including isolates displaying a wild-type (MIC90, 0.25/0.25 mg/L) or ESBL (MIC50/90, 0.5/1 mg/L) phenotype, and good activity against isolates displaying an AmpC-like phenotype (MIC range 0.25–4 mg/L). Ceftolozane/tazobactam demonstrated good overall activity (MIC50/90, 0.25/4 mg/L) against all 104 Klebsiella spp. isolates, although activity was lower against those with an ESBL phenotype (MIC50/90, 4/16 mg/L), and was inactive against the carbapenemaseproducing isolates (MIC  64 mg/L). Ceftolozane/tazobactam demonstrated excellent in

4 Page 4 of 41

vitro activity against most of the P. aeruginosa and Enterobacteriaceae clinical isolates obtained from medical centres in Spain, supporting the potential value of

Ac ce p

te

d

M

an

us

cr

ip t

ceftolozane/tazobactam in treating infections due to these pathogens.

5 Page 5 of 41

1. Introduction Gram-negative bacteria are responsible for the majority of healthcare-associated

ip t

infections, including urinary tract infections [1], intra-abdominal infections [2] and pneumonia [3], and are an important cause of nosocomial bloodstream infections (BSIs)

cr

[4]. Infections caused by Gram-negative bacteria have features that are of particular

us

concern; in particular, Gram-negative bacteria are highly adaptive and often possess multiple mechanisms of antibiotic resistance, especially in the presence of antibiotic

an

selection pressure [5]. In addition, there is increasing drug resistance in the absence of effective therapies, which makes selection of empirical therapy difficult [3,5].

M

Inappropriate initial antibiotic therapy is associated with increased mortality [6,7], hospital length of stay and hospital costs [8]. The majority of inappropriate initial

te

Ac ce p

effective therapies.

d

antibiotic therapy is attributed to drug resistance [7], highlighting the need for new

Ceftolozane/tazobactam is an antibacterial consisting of ceftolozane, a novel antipseudomonal cephalosporin, and tazobactam, a well established -lactamase inhibitor. In the phase 3 clinical trial ASPECT-cUTI, ceftolozane/tazobactam met its primary endpoint of non-inferior efficacy and was superior to high-dose extendedduration levofloxacin in the primary and key secondary endpoints in patients with complicated urinary tract infections (cUTIs), including pyelonephritis [9]. In the phase 3 trial ASPECT-cIAI, ceftolozane/tazobactam plus metronidazole met its primary endpoint of non-inferior efficacy to meropenem for clinical cure in patients with complicated intraabdominal infections (cIAIs) [10]. The phase 3 trial to assess the efficacy and safety of 6 Page 6 of 41

ceftolozane/tazobactam versus meropenem in the treatment of ventilated nosocomial pneumonia is ongoing [11]. Ceftolozane has demonstrated potent in vitro activity against Pseudomonas aeruginosa, including multidrug-resistant isolates, as well as

ip t

good activity against Enterobacteriaceae organisms but, similar to other cephalosporins [12], its activity can be reduced by the production of extended-spectrum -lactamases

cr

(ESBLs), carbapenemases and, to some degree, hyperproduction of AmpC -

us

lactamases. The addition of tazobactam broadens the activity of ceftolozane to include

an

most ESBL-producing Enterobacteriaceae [11,13,14].

M

Surveillance of antimicrobial resistance is a fundamental part of an effective response to the threat of resistance and provides an essential source of information on the

d

magnitude and trends of resistance at the local, national, regional and global levels as

te

well as geographical variations [15]. The purpose of the CENIT study (Ceftolozane/Tazobactam Activity Against Relevant Gram-negative Isolates) was to

Ac ce p

evaluate the in vitro activity of ceftolozane/tazobactam and several comparator agents against contemporary relevant clinical isolates of P. aeruginosa and Enterobacteriaceae prospectively collected in Spain from patients with cIAIs, cUTIs, lower respiratory tract infections (LRTIs) and BSIs. Isolates were further classified according to resistance phenotypes.

7 Page 7 of 41

2. Materials and methods 2.1. Sampling sites and organisms

ip t

Clinical isolates of P. aeruginosa and Enterobacteriaceae were prospectively and consecutively collected from January–September 2013 from inpatients and outpatients

cr

with cIAIs, cUTIs, LRTIs and BSIs at 10 Spanish tertiary care medical centres. Each

us

medical centre submitted 100 clinical isolates (50 P. aeruginosa and 50

Enterobacteriaceae). Only one isolate per patient was included. Isolate identification

an

was performed by the submitting site and was confirmed at the central laboratory (Department of Microbiology, Ramón y Cajal University Hospital, Madrid, Spain) using

M

matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-

te

d

TOF/MS) (Bruker Daltonik GmbH, Leipzig, Germany).

2.2. Antimicrobial susceptibility testing

Ac ce p

Minimum inhibitory concentrations (MICs) were determined by standard broth microdilution methodology as per the standard ISO method 20776-1:2006 [16] using dry-form Sensititre panels (Thermo Fisher Scientific, formerly Trek Diagnostic Systems Inc., Cleveland, OH) and were interpreted according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) [17] and Clinical and Laboratory Standards Institute (CLSI) [18] criteria. In the absence of CLSI breakpoints for ceftolozane/tazobactam, US Food and Drug Administration (FDA) breakpoints were applied [19]. Quality control was performed using the CLSI reference strains Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603 and P. aeruginosa 8 Page 8 of 41

ATCC 27853 [20]. Antimicrobial susceptibility testing was carried out for ceftolozane, ceftolozane/tazobactam, amoxicillin/clavulanic acid, piperacillin/tazobactam (TZP),

cr

2.3. Phenotypic classification of Pseudomonas aeruginosa

ip t

ceftazidime, cefotaxime, cefepime, imipenem, meropenem and levofloxacin.

us

Pseudomonas aeruginosa isolates were classified into different phenotypes according to CLSI non-susceptible and resistant breakpoints, as follows: TZP non-susceptibility;

an

ceftazidime non-susceptibility; meropenem non-susceptibility; combined TZP and ceftazidime non-susceptibility; combined TZP, ceftazidime and meropenem non-

M

susceptibility; and multidrug-resistant, meaning combined resistance to all agents tested

te

d

(TZP, ceftazidime, cefepime, imipenem, meropenem and levofloxacin) [18].

2.4. Phenotypic classification of Enterobacteriaceae

Ac ce p

Enterobacteriaceae isolates were classified into different phenotypes according to their susceptibilities to the -lactam antibiotics. The EUCAST epidemiological cut-off values were used to separate wild-type (WT) from non-WT isolates. Among the non-WT isolates, the following phenotypes were defined. (i) ESBL phenotype, isolates with an MIC ≥ 2 mg/L for cefotaxime, ceftazidime and/or cefepime and positive phenotypic confirmation of ESBL production using the double-disk synergy test [21,22]. (ii) Carbapenemase phenotype, isolates with an MIC > 1 mg/L for imipenem and/or an MIC > 0.12 mg/L for meropenem and positive phenotypic confirmation of carbapenemase production using the modified Hodge test and/or Carba NP test [21,23]. The

9 Page 9 of 41

combination disk test (Rosco Diagnostica A/S, Taastrup, Denmark) [24] was also used to discriminate different carbapenemase groups. And (iii) AmpC-like (AmpC hyperproduction or plasmid AmpC) phenotype, isolates with reduced susceptibility to

ip t

third-generation cephalosporins not characterised as ESBL- or carbapenemase-

producers. Cefoxitin resistance by disk diffusion assay and/or a positive induction test

us

cr

was used to confirm this phenotype [25].

an

3. Results

M

3.1. Distribution of isolates

A total of 1000 clinical isolates of P. aeruginosa (n = 500; Table 1) and

d

Enterobacteriaceae (n = 500; Table 2) were collected from inpatients (81.1%) and

te

outpatients (18.9%) with cIAIs, cUTIs, LRTIs and BSIs. There were 259 isolates obtained from cIAI specimens (25.9%), 263 from cUTIs (26.3%), 258 from LRTIs

Ac ce p

(25.8%) and 220 from BSIs (22.0%). Pseudomonas aeruginosa isolates were more commonly collected in LRTIs than Enterobacteriaceae (65.1% vs. 34.9%, respectively), whereas in cIAIs Enterobacteriaceae isolates were most commonly collected (36.3% P. aeruginosa vs. 63.7% Enterobacteriaceae). A similar number of P. aeruginosa and Enterobacteriaceae isolates were collected from UTI (51.0% vs. 49.0%) and BSI (47.3% vs. 52.7%) specimens.

10 Page 10 of 41

3.2. Ceftolozane/tazobactam activity against Pseudomonas aeruginosa Ceftolozane, alone and in combination with tazobactam, was the most potent agent tested against all P. aeruginosa isolates (MIC50/90 for both, 0.5/4 mg/L). Overall, 94.4%

ip t

of isolates were categorised as ceftolozane/tazobactam-susceptible when using the

cr

FDA breakpoints (Table 1).

us

Ceftolozane and ceftolozane/tazobactam were eight-fold more active than ceftazidime and cefepime (MIC50/90, 4/32 mg/L for both; 76% and 73% susceptible by EUCAST,

an

respectively), at least eight-fold more active than TZP (MIC50/90, 16/>32 mg/L; 63.6% susceptible by EUCAST), four-fold more active than imipenem (MIC50/90, 2/16 mg/L;

M

68.6% susceptible by EUCAST) and at least two-fold more active than meropenem

d

(MIC50/90, 1/16 mg/L; 64.6% susceptible by EUCAST) and levofloxacin (MIC50/90, 1/>8

te

mg/L; 54.6% susceptible by EUCAST) (Table 1; Fig. 1). The corresponding CLSI

Ac ce p

susceptibility values are included in Table 1.

Ceftolozane/tazobactam was active against many drug-resistant strains of P. aeruginosa, including TZP-non-susceptible (n = 182; MIC50/90, 2/16 mg/L; 84.6% susceptible according to FDA criteria), ceftazidime-non-susceptible (n = 120; MIC50/90, 2/>64 mg/L; 80.8% susceptible according to FDA criteria) and meropenem-nonsusceptible (n = 177; MIC50/90, 2/32 mg/L; 85.3% susceptible according to FDA criteria) isolates. Ceftolozane/tazobactam was also active against isolates with multidrug-nonsusceptibility, including those non-susceptible to TZP and ceftazidime (n = 116; MIC50/90, 2/>64 mg/L; 80.2% susceptible according to FDA criteria) and to TZP,

11 Page 11 of 41

ceftazidime and meropenem (n = 87; MIC50/90, 2/>64 mg/L; 75.9% susceptible according to FDA criteria). Notably, 64.7% of a group of 34 isolates that were resistant to all other antimicrobial agents tested were categorised as susceptible to ceftolozane/tazobactam

cr

ip t

according to FDA criteria.

us

3.3. Ceftolozane/tazobactam activity against Enterobacteriaceae 3.3.1. Escherichia coli

an

Ceftolozane/tazobactam demonstrated excellent overall activity (MIC50/90, 0.25/0.5

d

according to FDA criteria (Table 2).

M

mg/L) against all 250 E. coli isolates, with 99.6% of isolates classified as susceptible

te

The carbapenems imipenem (MIC50/90, ≤0.25/≤0.25 mg/L; 100% susceptible by EUCAST) and meropenem (MIC50/90, ≤0.12/≤0.12 mg/L; 100% susceptible by EUCAST)

Ac ce p

were the most potent agents tested against all E. coli isolates. At the MIC90 level, ceftolozane/tazobactam (MIC90, 0.5 mg/L) was the next most active agent (Table 2).

Ceftolozane/tazobactam exhibited potent activity against E. coli isolates displaying a WT phenotype (MIC50/90, 0.25/0.25 mg/L; 100% inhibited at MIC ≤ 0.5 mg/L) or an ESBL phenotype (MIC50/90, 0.5/1 mg/L; 100% inhibited at MIC ≤ 2 mg/L) and slightly lower activity against isolates displaying an AmpC-like phenotype (MIC range 0.25–4 mg/L) (Table 3) compared with ESBL-producers. Ceftolozane/tazobactam was more potent according to MICs against ESBL-producing E. coli than were TZP (MIC50/90, 4/32 mg/L),

12 Page 12 of 41

ceftazidime (MIC50/90, 8/64 mg/L), cefotaxime (MIC50/90, 64/>64 mg/L) and cefepime

ip t

(MIC50/90, 8/>64 mg/L) (Table 2).

3.3.2. Klebsiella spp.

cr

Ceftolozane/tazobactam demonstrated good overall activity (MIC50/90, 0.25/4 mg/L)

us

against all 104 isolates of Klebsiella spp., with 86.5% of isolates classified as susceptible according to FDA criteria (Table 2). The most active agents were

an

meropenem (MIC50/90, ≤0.12/≤0.12 mg/L; 96.1% susceptible by EUCAST), imipenem (MIC50/90, ≤0.25/0.5 mg/L; 95.1% susceptible by EUCAST) and ceftolozane/tazobactam

M

(MIC50/90, 0.25/4 mg/L) (Table 2).

d

Ceftolozane/tazobactam showed potent activity against Klebsiella spp. isolates

te

displaying WT and plasmid-mediated penicillinase phenotypes (MIC50/90, 0.25/0.5 mg/L

Ac ce p

and 0.5/0.5 mg/L, respectively), with 100% inhibited at an MIC of ≤1 mg/L (Table 3). Compared with what was observed in isolates with a WT phenotype, ceftolozane/tazobactam had lower activity when tested against ESBL-producers (MIC50/90, 4/16 mg/L), but its potency was greater than that of TZP (MIC50/90, 32/>32 mg/L), ceftazidime (MIC50/90, 32/>64 mg/L), cefotaxime (MIC50/90, 64/>64 mg/L) and cefepime (MIC50/90, 16/>64 mg/L) (Table 2). As expected, ceftolozane/tazobactam was inactive against the carbapenemase-producing isolates (MIC  64 mg/L) (Table 3).

13 Page 13 of 41

3.3.3. Enterobacter spp. The most active agents tested against all 70 isolates of Enterobacter spp. were meropenem (MIC50/90, ≤0.12/≤0.12 mg/L; 100% susceptible), levofloxacin (MIC50/90,

ip t

0.06/0.5 mg/L; 94.3% susceptible by EUCAST), cefepime (MIC50/90, 0.12/0.5 mg/L; 92.9% susceptible by EUCAST) and imipenem (MIC50/90, 0.5/1 mg/L; 100%

cr

susceptible). Ceftolozane/tazobactam was the next most active agent (MIC50/90, 0.5/4

us

mg/L; 87.2% susceptible according to FDA criteria) (Table 2).

an

Ceftolozane/tazobactam was highly active against isolates displaying a WT phenotype (MIC50/90, 0.25/0.5 mg/L; 100% inhibited at MIC ≤ 1 mg/L), yet showed reduced activity

M

against AmpC-hyperproducers (MIC50/90, 1/8 mg/L) and ESBL-producers (MIC range 4–

d

64 mg/L) (Table 3). Even so, ceftolozane/tazobactam was more active than TZP

Ac ce p

AmpC-hyperproducers.

te

(MIC50/90, 32/>32 mg/L), ceftazidime and cefotaxime (MIC50/90, 16/64 mg/L) against

3.3.4. Proteus spp.

The most active agents tested against all 36 isolates of Proteus spp. were cefotaxime, ceftazidime, cefepime and meropenem (Table 2). Using MIC90 values, ceftolozane/tazobactam (MIC90, 1 mg/L) was the next most active agent (Table 3). Ceftolozane/tazobactam was very active against all phenotypes (MIC50/90, 0.5/1; 100% susceptible according to FDA criteria).

14 Page 14 of 41

3.3.5. Serratia marcescens The most active agents tested against all 17 S. marcescens isolates were meropenem,

0.5/1 mg/L; 100% susceptible according to FDA criteria) (Table 2).

ip t

cefepime, levofloxacin and ceftazidime, followed by ceftolozane/tazobactam (MIC50/90,

Ceftolozane/tazobactam was active against isolates displaying a WT phenotype

cr

(MIC50/90, 0.5/1 mg/L; 100% inhibited at MIC ≤ 1 mg/L). The MIC of

us

ceftolozane/tazobactam for the one AmpC-hyperproducer was slightly higher at 2 mg/L

an

(Table 3).

M

3.3.6. Citrobacter spp.

The most active agents tested against all 12 isolates of Citrobacter spp. were

d

meropenem, imipenem, levofloxacin and cefepime. Using MIC90 values,

te

ceftolozane/tazobactam (MIC90, 8 mg/L; 83.3% susceptible according to FDA criteria)

Ac ce p

was the next most active agent (Table 2). Ceftolozane/tazobactam was highly potent against isolates displaying a WT phenotype (MIC50/90, 0.25/0.5; 100% inhibited at MIC ≤ 0.5 mg/L), whereas it had reduced potency against AmpC-hyperproducers (MICs of 1 mg/L and 8 mg/L) and was inactive against the carbapenemase-producing Citrobacter braakii isolate (MIC > 64 mg/L) (Table 3).

3.3.7. Morganella morganii The most active agents tested against all 10 M. morganii isolates were cefepime, meropenem and TZP (Table 2). Using MIC90 values, ceftolozane/tazobactam was the

15 Page 15 of 41

next most active agent (MIC90, 0.5 mg/L; 100% susceptible according to FDA criteria). Of the 10 isolates, 6 were categorised as WT and 4 as AmpC-hyperproducers and the MICs of ceftolozane/tazobactam were similar (MICs for both phenotypes between 0.25

cr

ip t

mg/L and 0.5 mg/L) (Table 3).

us

3.4. Ceftolozane/tazobactam activity against Enterobacteriaceae and Pseudomonas aeruginosa according to patient location and infection type

an

The MIC50/90 values of ceftolozane/tazobactam were slightly higher among P. aeruginosa isolates obtained from inpatients (MIC50, 1 mg/L; MIC90, 4 mg/L) relative to

M

isolates obtained from outpatients (MIC50, 0.5 mg/L; MIC90, 2 mg/L). Similar results were obtained for Enterobacteriaceae (inpatients: MIC50, 0.25 mg/L, MIC90, 1 mg/L;

d

outpatients: MIC50, 0.25 mg/L; MIC90, 0.5 mg/L). However, these noted differences are

te

within the error of the broth microdilution assay. No notable differences were apparent

Ac ce p

in the in vitro activity of ceftolozane/tazobactam against P. aeruginosa and Enterobacteriaceae with respect to the infection type.

4. Discussion

The results from this study are important in view of the growing public health threat posed by antimicrobial resistance [15]. In Europe, antimicrobial resistance rates are increasing and Spain has one of the highest rates of antimicrobial resistance as well as of antibiotic consumption [26,27].

16 Page 16 of 41

In Spain in 2012, resistance in E. coli isolates was found at rates of 65.4%, 33.9%, 15.6%, 13.5% and 0.1% for aminopenicillins, fluoroquinolones, aminoglycosides, thirdgeneration cephalosporins and carbapenems, respectively, whilst 5.9% were found to

ip t

be multidrug-resistant (resistance to fluoroquinolones, third-generation cephalosporins and aminoglycosides) [15]. For P. aeruginosa isolates, resistance to fluoroquinolones,

cr

aminoglycosides, carbapenems, ceftazidime and TZP was found at rates of 21.0%,

us

16.5%, 16.4%, 8.9% and 6.7%, respectively, whilst multidrug resistance (resistance to three or more antibiotic classes among TZP, ceftazidime, fluoroquinolones,

an

aminoglycosides and carbapenems) was found in 10.8% of isolates [15].

M

Ceftolozane/tazobactam is a novel antibacterial that provides potential advantages with

d

the current microbial resistance situation as its activity includes isolates resistant to

te

other -lactams, fluoroquinolones and aminoglycosides as well as those with multidrug resistance [13]. In the present study, the antimicrobial susceptibility of Gram-negative

Ac ce p

isolates from patients with various clinical infections including cIAIs, cUTIs, LRTIs and BSIs in medical centres in Spain showed that very few current agents were active against the most frequently isolated organisms. The antipseudomonal cephalosporins (ceftazidime and cefepime), TZP and meropenem showed susceptibilities values lower than 80% in P. aeruginosa, with 6.8% of isolates resistant to all antibiotic tested (multidrug-resistant phenotype), highlighting the urgent need for new antibacterials to treat these infections in clinical patients. Furthermore, with the exception of the carbapenems, these antibacterials showed limited activity against ESBL phenotype E. coli and Klebsiella spp.

17 Page 17 of 41

Data from the CENIT study showed that ceftolozane/tazobactam exhibited potent in vitro activity against WT Enterobacteriaceae isolates and ESBL-producing E. coli

ip t

isolates but had moderate activity against some ESBL-producing Klebsiella spp.

isolates and AmpC-hyperproducers. However, when considering all ESBL-producing

cr

isolates and AmpC-hyperproducers, ceftolozane/tazobactam demonstrated greater in

us

vitro activity than TZP, ceftazidime and cefotaxime. Ceftolozane/tazobactam was inactive against all five carbapenemase-producing Enterobacteriaceae isolates tested. It

an

has been previously reported that tazobactam is not active against carbapenemases

M

[28].

d

For P. aeruginosa, ceftolozane/tazobactam was the most potent agent tested against all

te

isolates. Unlike in Enterobacteriaceae, it is important to note that the addition of tazobactam did not produce significant enhancement of the in vitro activity of

Ac ce p

ceftolozane against P. aeruginosa isolates. This is likely to be because of the fact that the activity of ceftolozane is not affected by some of the main resistance mechanisms for P. aeruginosa (AmpC -lactamase overproduction, efflux pumps and loss of OprD) [29]. The higher activity of ceftolozane/tazobactam compared with the other antipseudomonal agents evaluated was maintained regardless of resistance phenotype, even against isolates resistant to multiple antibiotics.

18 Page 18 of 41

The data in this study conducted in Spain are consistent with previous large surveillance studies that have evaluated the activity of ceftolozane/tazobactam in the USA, Canada

ip t

and Europe and will be useful for positioning this antimicrobial agent [3,13,30].

cr

5. Conclusion

us

In conclusion, currently no antimicrobial agent or combination allows complete coverage of multidrug-resistant Enterobacteriaceae and P. aeruginosa isolates.

an

Ceftolozane/tazobactam demonstrated excellent in vitro activity against P. aeruginosa and most of the Enterobacteriaceae clinical isolates obtained from medical centres in

M

Spain. Taken together, the data presented in this study confirm the activity of ceftolozane/tazobactam against organisms recovered from cIAIs, cUTIs, LRTIs and

d

BSIs, including those that are caused by multidrug-resistant pathogens. These results

te

support, from a microbiological point of view, the potential value of

Ac ce p

ceftolozane/tazobactam in treating these infections.

Acknowledgments: The authors thank the investigators of the CENIT study group: Dr Emilia Cercenado and Dr Emilio Bouza Santiago [Hospital General Universitario Gregorio Marañón and CIBER de Enfermedades Respiratorias (CIBERES) CB06/06/0058, Madrid, Spain], Dr Francesc Marco Reverte and Dr Vila (Hospital Clínic i Provincial de Barcelona, Barcelona, Spain), Dr Pilar Egea and Dr Álvaro Pascual Hernández (Hospital Universitario Virgen Macarena, Seville, Spain), Dr Jorge Calvo and Dr Luis Martínez-Martínez (Hospital Universitario Marqués de Valdecilla, Santander, Spain), Dr Germán Bou Arévalo (Hospital Universitario Juan Canalejo, A Coruña, 19 Page 19 of 41

Spain), Dr Concepción Gimeno Cardona (Consorcio Hospital General Universitario de Valencia, Valencia, Spain), Dr Enrique Ruiz de Gopegui and Dr Antonio Oliver (Hospital Universitario Son Espases, Palma de Mallorca, Spain), Dr Inmaculada García and Dr

ip t

José Elías García Sánchez (Hospital Universitario Salamanca, Salamanca, Spain), and Dr Fátima Galán-Sánchez and Dr Manuel A. Rodríguez Iglesias (Hospital Universitario

cr

Puerta del Mar, Cádiz, Spain). Medical writing support was provided by Christina

us

Campbell of PAREXEL and was funded by Cubist (Lexington, MA).

an

Funding: This study was funded by a research grant from Cubist Pharmaceuticals

M

(Lexington, MA).

d

Competing interests: RC has received research support from Cubist Pharmaceuticals,

te

AstraZeneca and MSD. All other authors declare no competing interests.

Ac ce p

Ethical approval: Not required.

20 Page 20 of 41

References [1] Sievert DM, Ricks P, Edwards JR, Schneider A, Patel J, Srinivasan A, et al.

ip t

Antimicrobial-resistant pathogens associated with healthcare-associated infections: summary of data reported to the National Healthcare Safety Network

cr

at the Centers for Disease Control and Prevention, 2009–2010. Infect Control

us

Hosp Epidemiol 2013;34:1–14.

[2] Sartelli M, Catena F, Ansaloni L, Leppaniemi A, Taviloglu K, van Goor H, et al.

an

Complicated intra-abdominal infections in Europe: preliminary data from the first three months of the CIAO Study. World J Emerg Surg 2012;7:15.

M

[3] Sader HS, Farrell DJ, Flamm RK, Jones RN. Antimicrobial susceptibility of Gramnegative organisms isolated from patients hospitalised with pneumonia in US and

d

European hospitals: results from the SENTRY Antimicrobial Surveillance

te

Program, 2009–2012. Int J Antimicrob Agents 2014;43:328–34.

Ac ce p

[4] Marcos M, Soriano A, Iñurrieta A, Martínez JA, Romero A, Cobos N, et al. Changing epidemiology of central venous catheter-related bloodstream infections: increasing prevalence of Gram-negative pathogens. J Antimicrob Chemother 2011;66:2119–25. [5] Peleg AY, Hooper DC. Hospital-acquired infections due to Gram-negative bacteria. N Engl J Med 2010;362:1804–13. [6] Joo EJ, Kang CI, Ha YE, Park SY, Kang SJ, Wi YM, et al. Impact of inappropriate empiric antimicrobial therapy on outcome in Pseudomonas aeruginosa bacteraemia: a stratified analysis according to sites of infection. Infection 2011;39:309–18. 21 Page 21 of 41

[7] Micek S, Johnson MT, Reichley R, Kollef MH. An institutional perspective on the impact of recent antibiotic exposure on length of stay and hospital costs for patients with Gram-negative sepsis. BMC Infect Dis 2012;12:56.

ip t

[8] Mauldin PD, Salgado CD, Hansen IS, Durup DT, Bosso JA. Attributable hospital cost and length of stay associated with health care-associated infections caused

cr

by antibiotic-resistant Gram-negative bacteria. Antimicrob Agents Chemother

us

2010;54:109–15.

[9] Wagenlehner F, Umeh O, Huntington J, Cloutier D, Friedland I, Steenbergen J,

an

et al. Efficacy and safety of ceftolozane/tazobactam versus levofloxacin in the treatment of complicated urinary tract infections (cUTI) including pyelonephritis in

M

hospitalized adults: results from the phase 3 ASPECT-cUTI trial. In: 24th

d

European Congress of Clinical Microbiology and Infectious Diseases (ECCMID);

eP449].

Eckmann C, Hershberger E, Miller B, Wooley M, Friedland I, Steenbergen

Ac ce p

[10]

te

10–13 May 2014; Barcelona, Spain. Basel, Switzerland: ESCMID; 2014 [poster

J, et al. Efficacy and safety of ceftolozane/tazobactam versus meropenem in the treatment of complicated intra-abdominal infections (cIAI) in hospitalized adults: results from the phase 3 ASPECT-cIAI trial. In: 24th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID); 10–13 May 2014; Barcelona, Spain. Basel, Switzerland: ESCMID; 2014 [poster P0266a]. [11]

Zhanel GG, Chung P, Adam H, Zelenitsky S, Denisuik A, Schweizer F, et

al. Ceftolozane/tazobactam: a novel cephalosporin/-lactamase inhibitor

22 Page 22 of 41

combination with activity against multidrug-resistant Gram-negative bacilli. Drugs 2014;74:31–51. [12]

Sader HS, Rhomberg PR, Farrell DJ, Jones RN. Antimicrobial activity of

ip t

CXA-101, a novel cephalosporin tested in combination with tazobactam against Enterobacteriaceae, Pseudomonas aeruginosa, and Bacteroides fragilis strains

cr

having various resistance phenotypes. Antimicrob Agents Chemother

[13]

us

2011;55:2390–4.

Farrell DJ, Flamm RK, Sader HS, Jones RN. Antimicrobial activity of

an

ceftolozane–tazobactam tested against Enterobacteriaceae and Pseudomonas aeruginosa with various resistance patterns isolated in U.S. hospitals (2011–

Titelman E, Karlsson IM, Ge Y, Giske CG. In vitro activity of CXA-101 plus

d

[14]

M

2012). Antimicrob Agents Chemother 2013;57:6305–10.

te

tazobactam (CXA-201) against CTX-M-14- and CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae. Diagn Microbiol Infect Dis 2011;70:137–41. European Centre for Disease Prevention and Control. Antimicrobial

Ac ce p

[15]

resistance surveillance in Europe. Annual report of the European Antimicrobial Resistance Surveillance Network (EARS-Net) 2012. ECDC. http://ecdc.europa.eu/en/publications/Publications/antimicrobial-resistancesurveillance-europe-2012.pdf [accessed 28 July 2015]. [16]

International Organization for Standardization. ISO 20776-1:2006. Clinical

laboratory testing and in vitro diagnostic test systems—Susceptibility testing of infectious agents and evaluation of performance of antimicrobial susceptibility test devices—Part 1: Reference method for testing the in vitro activity of

23 Page 23 of 41

antimicrobial agents against rapidly growing aerobic bacteria involved in infectious diseases. http://www.iso.org/iso/catalogue_detail.htm?csnumber=41630 [accessed 23

[17]

ip t

December 2014].

European Committee on Antimicrobial Susceptibility Testing. Breakpoint

cr

tables for interpretation of MICs and zone diameters. Version 4.0, 2014.

us

EUCAST; 2014.

http://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/Breakpoint_table

[18]

an

s/Breakpoint_table_v_4.0.pdf [accessed 28 July 2015].

Clinical and Laboratory Standards Institute. Performance standards for

M

antimicrobial susceptibility testing; twenty-third informational supplement.

Cubist Pharmaceuticals. Prescribing information for ZERBAXATM.

te

[19]

d

Document M100-S23. Wayne, PA: CLSI; 2013.

Lexington, MA: Cubist Pharmaceuticals; 2015.

Ac ce p

http://www.zerbaxa.com/pdf/PrescribingInformation.pdf [accessed 1 June 2015]. [20]

Clinical and Laboratory Standards Institute. Methods for dilution

antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard—ninth edition. Document M07-A9. Wayne, PA: CLSI; 2012. [21]

European Committee on Antimicrobial Susceptibility Testing. EUCAST

guidelines for detection of resistance mechanisms and specific resistances of clinical and/or epidemiological importance. Version 1.0, December 2013. EUCAST; 2013. http://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/Resistance_mec

24 Page 24 of 41

hanisms/EUCAST_detection_of_resistance_mechanisms_v1.0_20131211.pdf [accessed 28 July 2015]. [22]

Jarlier V, Nicolas MH, Fournier G, Philippon A. Extended broad-spectrum

ip t

-lactamases conferring transferable resistance to newer -lactam agents in

Enterobacteriaceae: hospital prevalence and susceptibility patterns. Rev Infect

Nordmann P, Poirel L, Dortet L. Rapid detection of carbapenemase-

us

[23]

cr

Dis 1988;10:867–78.

producing Enterobacteriaceae. Emerg Infect Dis 2012;18:1503–7. van Dijk K, Voets GM, Scharringa J, Voskuil S, Fluit AC, Rottier WC, et al.

an

[24]

A disc diffusion assay for detection of class A, B and OXA-48 carbapenemases

M

in Enterobacteriaceae using phenyl boronic acid, dipicolinic acid and temocillin.

Livermore DM. -Lactamases in laboratory and clinical resistance. Clin

te

[25]

d

Clin Microbiol Infect 2014;20:345–9.

Microbiol Rev 1995;8:557–84.

Oteo J, Lázaro E, de Abajo FJ, Baquero F, Campos J; Spanish members

Ac ce p

[26]

of EARSS. Antimicrobial-resistant invasive Escherichia coli, Spain. Emerg Infect Dis 2005;11:546–53. [27]

van de Sande-Bruinsma N, Grundmann H, Verloo D, Tiemersma E,

Monen J, Goossens H, et al. Antimicrobial drug use and resistance in Europe. Emerg Infect Dis 2008;14:1722–30. [28]

Livermore DM, Mushtaq S, Ge Y. Chequerboard titration of cephalosporin

CXA-101 (FR264205) and tazobactam versus -lactamase-producing Enterobacteriaceae. J Antimicrob Chemother 2010;65:1972–4.

25 Page 25 of 41

[29]

Takeda S, Nakai T, Wakai Y, Ikeda F, Hatano K. In vitro and in vivo

activities of a new cephalosporin, FR264205, against Pseudomonas aeruginosa. Antimicrob Agents Chemother 2007;51:826–30. Walkty A, Karlowsky JA, Adam H, Baxter M, Lagace-Wiens P, Hoban DJ,

ip t

[30]

et al. In vitro activity of ceftolozane–tazobactam against Pseudomonas

cr

aeruginosa isolates obtained from patients in Canadian hospitals in the

Ac ce p

te

d

M

an

us

CANWARD study, 2007 to 2012. Antimicrob Agents Chemother 2013;57:5707–9.

26 Page 26 of 41

Fig. 1. Cumulative percentage minimum inhibitory concentration (MIC) distributions of

Ac ce p

te

d

M

an

us

cr

ip t

ceftolozane/tazobactam and comparators against all 500 Pseudomonas aeruginosa.

27 Page 27 of 41

ip t cr

Table 1

us

Antimicrobial activity of ceftolozane/tazobactam and comparator agents against Pseudomonas aeruginosa, including resistant phenotypes a

Susceptibility

MIC50 MIC90 Range

%S

%I

%R

%S

%I

%R

Ceftolozane

0.5

4

M an

Organism (no. tested)/antimicrobial MIC (mg/L)

0.12 to >64













Ceftolozane/tazobactam

0.5

4

0.12 to >64







94.4 b 1.2 b

TZP

16

>32

63.6 –

36.4 63.6

36.4 c

Ceftazidime

4

32

0.12 to >64

76



24

76

5.8

18.2

73



27

73

15.2

11.8

23

60

8.6

31.4

EUCAST

4.4 b

≤2 to >32

4

32

0.06 to >64

2

16

≤0.25 to >16 68.6 8.4

1

16

≤0.12 to >16 64.6 20.8 14.6 64.6

10.8

24.6

1

>8

≤0.015 to >8 54.6 7

38.4 61.6

7.4

31

2

16

0.25 to >64













Ceftolozane/tazobactam

2

16

0.5 to >64







84.6 b 3.3 b

TZP

>32

>32

32 to >32

0



100

0

Ceftazidime

16

64

1 to >64

36.3 –

63.7 36.3

14.3

49.4

Cefepime

16

64

1 to >64

29.7 –

70.3 29.7

39

31.3

Cefepime Imipenem Meropenem Levofloxacin

ce pt

ed

All P. aeruginosa (n = 500)

CLSI

Ceftolozane

Ac

TZP non-susceptible (n = 182)

12.1 b

100 c

1 Page 28 of 41

ip t

Imipenem

8

>16

0.5 to >16

36.8 14.3 48.9 31.3

Meropenem

8

>16

≤0.12 to >16 29.7 31.3 39

Levofloxacin

>8

>8

0.12 to >8

63.2

13.2

57.1

17.6 11.5 70.9 29.1

9.9

61





us

cr

5.5

Ceftazidime non-susceptible (n = 120)

29.7

2

>64

0.5 to >64









Ceftolozane/tazobactam

2

>64

0.5 to >64







80.8 b 4.2 b

TZP

>32

>32

8 to >32

3.3



96.7 3.3

96.7 c

Ceftazidime

32

>64

16 to >64

0



100

24.2

75.8

Cefepime

16

64

4 to >64

10.8 –

46.7

42.5

Imipenem

8

>16

1 to >16

30.8 12.5 56.7 25

5.8

69.2

Meropenem

8

>16

≤0.12 to >16 27.5 34.2 38.3 27.5

10.8

61.7

Levofloxacin

>8

>8

0.12 to >8

18.3 2.5

79.2 20.8

5.8

73.4

0.25 to >64





ce pt

ed

M an

Ceftolozane

0

89.2 10.8

15.0 b

Meropenem non-susceptible (n = 177) Ceftolozane

2

16



2.2

12.5 b

0.25 to >64



TZP

>32

>32

4 to >32

27.7 –

72.3 27.7

72.3 c

8

64

2 to >64

50.8 –

49.2 50.8

7.4

41.8

16

64

2 to >64

41.2 –

58.8 41.2

31.1

27.7

16

>16

0.5 to >16

16.4 20.9 62.7 11.3

5.1

83.6

Meropenem

8

>16

4 to >16

0

30.5

69.5

Levofloxacin

>8

>8

0.12 to >8

22.5 6.2

10.7

60.5

Ac

32

Imipenem

85.3

– b

2

Cefepime



– b

Ceftolozane/tazobactam Ceftazidime





58.8 41.2 0 71.3 28.8

TZP + ceftazidime non-susceptible (n = 116) 2 Page 29 of 41

>64

0.5 to >64



Ceftolozane/tazobactam

2

>64

0.5 to >64



TZP

>32

>32

32 to >32

0

Ceftazidime

32

64

16 to >64

Cefepime

16

64

4 to >64

Imipenem

16

>16

1 to >16

Meropenem

8

>16

≤0.12 to >16 25

Levofloxacin

>8

>8

0.12 to >8



ip t

2









80.2 b 4.3 b



100

0

100 c

0



100

0

22.4

77.6

7.8



92.2 7.8

48.2

44

5.2

71.5

11.2

63.8

M an

us

cr

Ceftolozane



28.5 12.9 58.6 23.3 35.3 39.7 25

– 15.5 b

16.4 2.6

81

19

6

75





TZP + ceftazidime + meropenem non-susceptible (n = 87) 2

>64

1 to >64









Ceftolozane/tazobactam

2

>64

1 to >64







75.9 b 3.4 b

TZP

>32

>32

32 to >32

0



100

0

100 c

0

14.9

Imipenem Meropenem Levofloxacin

ce pt

Cefepime

Ac

Ceftazidime

ed

Ceftolozane

32

64

16 to >64

0



100

16

64

8 to >64

1.1



98.9 1.1

16

>16

1 to >16

5.8

17.2 77

16

>16

4 to >8

0

>8

>8

0.5 to >8

4

>64

2 to >64

20.7 b 85.1

49.45 49.45

4.6

1.1

94.3

47.1 52.9 0

14.9

85.1

6.9

0

93.1 6.9

4.6

88.5







Multidrug-resistant (n = 34) d Ceftolozane



– b

2.9

– b

Ceftolozane/tazobactam

4

>64

2 to >64







64.7

TZP

>32

>32

>32

0



100

0

100 c

Ceftazidime

64

>64

32 to >64

0



100

0

0

32.4 b 100

3 Page 30 of 41

32 to >64

0

Imipenem

16

>16

8 to >16

0

Meropenem

>16

>16

8 to >16

0

Levofloxacin

>8

>8

8 to >8



ip t

>64

100

0

0

100

94.1 0

0

100

14.7 85.3 0

0

100

0

0

100

cr

32

5.9

us

Cefepime

0

100

0

M an

MIC, minimum inhibitory concentration; MIC50/90, MIC that inhibits 50% and 90% of the isolates, respectively; EUCAST, European Committee on Antimicrobial Susceptibility Testing; CLSI, Clinical and Laboratory Standards Institute; S, susceptible; I, intermediate; R, resistant; TZP, piperacillin/tazobactam; FDA, US Food and Drug Administration. – indicates non-published interpretative criteria.

Resistance phenotypes were defined according to CLSI criteria [18].

b

In the absence of CLSI breakpoints, FDA breakpoints were applied.

c

MIC range tested for TZP does not allow differentiation between the CLSI intermediate (I) and resistant (R) categories.

d

Multidrug-resistant, resistant to all agents tested (TZP, ceftazidime, cefepime, imipenem, meropenem and levofloxacin).

Ac

ce pt

ed

a

4 Page 31 of 41

ip t cr

Table 2

us

Antimicrobial activity of ceftolozane/tazobactam and comparator agents against Enterobacteriaceae, including resistant phenotypes a

Susceptibility

M an

Organism (no. tested)/ antimicrobial MIC (mg/L)

EUCAST

CLSI

MIC50 MIC90 Range

%S

%I

%R

%S

%I

%R

Ceftolozane

0.25

4

0.12 to >64













Ceftolozane/tazobactam

0.25

0.5

0.06–4







99.6 b 0.4 b

16

>16

≤2 to >16

41.2 –

Amoxicillin/clavulanic acid

Ceftazidime Cefepime Imipenem Meropenem Levofloxacin

Ac

Cefotaxime

4

16

ce pt

TZP

ed

All Escherichia coli (n = 250)

≤2 to >32

87.2 5.2

58.8 41.2 7.6

25.6

92.4

7.6

0b 33.2

c

0.06

8

≤0.03 to >64 85.6 0.8

13.6 85.6

0.8

13.6

0.25

2

≤0.03 to >64 87.2 4.4

8.4

91.6

2.0

6.4

0.06

4

≤0.03 to >64 88.4 3.6

8.0

94.4

1.2

4.4

≤0.25 ≤0.25 ≤0.25–1

100

0

0

100

0

0

≤0.12 ≤0.12 ≤0.12

100

0

0

100

0

0

0.06

>8

≤0.015 to >8 64.8 0

35.2 56.4

8.4

35.2

Ceftolozane

8

32

1–64













Ceftolozane/tazobactam

0.5

1

0.25–2







100 b

0b

0b

Amoxicillin/clavulanic acid

16

>16

4 to >16

6.7



93.3 33.3

36.7

30.0

ESBL phenotype E. coli (n = 30)

1 Page 32 of 41

ip t

4

32

≤2 to >32

73.4 13.3 13.3 86.7

13.3 c

Cefotaxime

64

>64

0.25 to >64

3.4

0

96.6

Ceftazidime

8

64

0.5 to >64

13.3 33.3 53.4 46.7

13.3

40.0

Cefepime

8

>64

0.5 to >64

20.0 16.7 63.3 56.7

10.0

33.3

Imipenem

≤0.25 ≤0.25 ≤0.25–1

100

0

0

100

0

0

Meropenem

≤0.12 ≤0.12 ≤0.12

100

0

0

100

0

0

Levofloxacin

>8

>8

0.03 to >8

13.3 0

86.7 10.0

3.3

86.7

Ceftolozane

0.25

64

0.12 to >64













Ceftolozane/tazobactam

0.25

4

0.12 to >64







86.5 b 4.8 b

2

>16

2 to >16

64.4 –

35.6 70.1

4.8

4

64

77.0 4.8

18.2 81.7

18.3 c

Ceftazidime Cefepime Imipenem Meropenem Levofloxacin

8.7 b

us

M an

0.06

>64

0.03 to >64

81.7 0.9

17.3 81.7

0.9

17.3

0.25

32

0.06 to >64

78.8 2.9

18.3 81.7

2.9

15.4

0.06

32

0.03 to >64

83.7 2.9

13.4 87.5

1.0

11.5

≤0.25 to >16 95.1 1.9

2.88 95.1

1.9

2.8

≤0.12 ≤0.12 ≤0.12 to >16 96.1 0.9

2.88 95.1

0.9

3.8

0.06

≤0.25 0.5

Ac

Cefotaxime

96.6 3.4

2–64

ce pt

TZP

0

ed

All Klebsiella spp. d (n = 104)

Amoxicillin/clavulanic acid

cr

TZP

25

>8

0.015 to >8

80.7 0

19.2 67.3

13.4

19.2





ESBL phenotype Klebsiella spp. e (n = 16) Ceftolozane

64

>64

2 to >64









Ceftolozane/tazobactam

4

16

0.5–16







43.8 b 31.2 b 25.0 b

Amoxicillin/clavulanic acid

>16

>16

8 to >16

0

0

100

6.3

6.3

87.4

2 Page 33 of 41

>32

8 to >32

12.5 25.0 62.5 37.5

62.5 c

Cefotaxime

64

>64

0.12 to >64

12.5 6.2

6.2

81.3

Ceftazidime

32

>64

2 to >64

0

18.8

68.7

Cefepime

16

>64

0.12 to >64

18.8 18.8 62.4 43.8

6.2

50.0

Imipenem

≤0.25 1

≤0.25–2

93.8 6.2

0

93.8

6.2

0

Meropenem

≤0.12 ≤0.12 ≤0.12–4

93.8 6.2

0

93.8

0

6.2

Levofloxacin

0.5

>8

0.06 to >8

56.3 0

43.7 37.5

18.8

43.7

Ceftolozane

0.5

4

M an

ip t

32

0.06 to >64













Ceftolozane/tazobactam

0.5

4

0.06–64







87.2 b 5.7 b

7.1 b

>16

>16

>16

0



100

0

0

100

4

>32

≤2 to >32

74.3 5.7

20

80

20 c

Amoxicillin/clavulanic acid

Ceftazidime Cefepime Imipenem Meropenem Levofloxacin

Ac

Cefotaxime

ce pt

TZP

ed

All Enterobacter spp. f (n = 70)

cr

TZP

81.3 12.5

us

12.5 87.5 12.5

0.25

64

≤0.03 to >64 67.1 2.9

30

67.1

2.9

30

0.5

32

≤0.03 to >64 68.6 7.1

24.3 75.7

5.7

18.6

0.12

0.5

≤0.03 to >64 92.9 2.8

4.3

95.7

0

4.3

0.5

1

≤0.25–1

≤0.12 ≤0.12 ≤0.12–0.5

0.06

0.5

100

0

0

100

0

0

100

0

0

100

0

0

5.7

81.4

12.9

5.7





≤0.015 to >8 94.3 0

AmpC-hyperproduction phenotype Enterobacter spp. g (n = 20) Ceftolozane

2

32

0.5–64









Ceftolozane/tazobactam

1

8

0.25–32







70.0 b 15.0 b 15.0 b

Amoxicillin/clavulanic acid

>16

>16

>16

0



100

0

0

100

3 Page 34 of 41

ip t

32

>32

≤2 to >32

25

15

60

40

60 c

Cefotaxime

16

64

2 to >64

0

10

90

0

10

90

Ceftazidime

16

64

1 to >64

5

25

70

30

15

55

Cefepime

0.25

1

0.06–4

90

10

0

100

0

0

Imipenem

0.5

1

0.5–1

100

0

0

100

0

0

Meropenem

≤0.12 ≤0.12 ≤0.12–0.25

100

0

0

100

0

0

Levofloxacin

0.06

4

0.03 to >8

85

0

15

70

15

15

Ceftolozane

0.5

1

0.12–4













Ceftolozane/tazobactam

0.5

1

0.12–1







100 b

0b

0b

≤2

>16

≤2 to >16

66.6 –

33.3 69.4

5.5

25

≤2

≤2

≤2

100

0

100

0c

≤0.03 0.25

≤0.03–4

97.2 0

2.7

97.2

0

2.7

0.06

0.12

0.06–4

97.2 2.7

0

100

0

0

0.06

0.25

≤0.03–0.5

100

0

100

0

0

2

2

≤0.25–4

41.7 58.3 0

41.7

52.7

5.5

≤0.12 ≤0.12 ≤0.12

100

0

100

0

0

0.12

>8

0.03 to >8

66.6 8.3

25

55.5

11.1

33.3

Ceftolozane

0.5

1

0.5–1













Ceftolozane/tazobactam

0.5

1

0.5–2







100 b

0b

0b

Amoxicillin/clavulanic acid

>16

>16

>16

0



100

0

0

100

Amoxicillin/clavulanic acid

Ceftazidime Cefepime Imipenem Meropenem Levofloxacin

Ac

Cefotaxime

us

M an

ce pt

TZP

ed

Proteus spp. h (n = 36)

cr

TZP

0

0 0

Serratia marcescens (n = 17)

4 Page 35 of 41

ip t

4

8

≤2–16

94.1 5.9

0

100

0c

Cefotaxime

0.5

1

0.12–4

94

0

6

94

0

6

Ceftazidime

0.25

0.5

0.12–2

94

0

6

94

0

6

Cefepime

0.12

0.12

0.06–0.25

100

0

0

100

0

0

Imipenem

1

1

0.5–1

100

0

0

100

0

0

Meropenem

≤0.12 ≤0.12 ≤0.12–0.25

100

0

0

100

0

0

Levofloxacin

0.12

0.25

0.12–0.5

100

0

0

100

0

0

Ceftolozane

0.5

32

0.25 to >64













Ceftolozane/tazobactam

0.25

8

0.25 to >64







83.3 b 0 b

16.7 b

>16

>16

≤2 to >16

25



75

25

75

4

>32

≤2 to >32

83.3 0

16.6 83.3

16.6 c

Amoxicillin/clavulanic acid

0

us

M an

0.12

64

0.06 to >64

75

0

25

75

0

25

0.5

64

0.12 to >64

75

0

25

75

0

25

0.12

2

≤0.03 to >64 83.3 8.3

8.3

91.6

0

8.3

1

1

≤0.25–4

91.6 8.3

0

91.6

0

8.3

≤0.12 ≤0.12 ≤0.12–8

91.6 8.3

0

91.6

0

8.3

0.06

1

0.03 to >8

91.6 0

8.3

66.6

25

8.3

Ceftolozane

0.5

8

0.25–16













Ceftolozane/tazobactam

0.25

0.5

0.25–0.5







100 b

0b

0b

Amoxicillin/clavulanic acid

>16

>16

>16

0

0

100

0

0

100

Ceftazidime Cefepime Imipenem Meropenem Levofloxacin

Ac

Cefotaxime

ce pt

TZP

ed

Citrobacter spp. i (n = 12)

cr

TZP

Morganella morganii (n = 10)

5 Page 36 of 41

ip t

≤2

≤2

≤2

100

0

0

100

0c

Cefotaxime

0.12

8

≤0.03–16

60

10

30

60

10

30

Ceftazidime

0.12

16

0.06–32

60

20

20

80

0

20

Cefepime

0.06

0.06

≤0.03–0.12

100

0

0

100

0

0

Imipenem

4

4

2–4

0

100

0

0

10

90

Meropenem

≤0.12 0.25

≤0.12–0.25

100

0

0

100

0

0

Levofloxacin

0.06

0.03–2

70

30

0

70

0

30

us

M an

2

cr

TZP

MIC, minimum inhibitory concentration; MIC50/90, MIC that inhibits 50% and 90% of the isolates, respectively; EUCAST,

ed

European Committee on Antimicrobial Susceptibility Testing; CLSI, Clinical and Laboratory Standards Institute; S, susceptible; I, intermediate; R, resistant; TZP, piperacillin/tazobactam; ESBL, extended-spectrum -lactamase; FDA, US

ce pt

Food and Drug Administration.

– indicates non-published interpretative criteria. a

One isolate of Salmonella enterica is not included in the table. The isolate was susceptible to ceftolozane/tazobactam

Ac

(MIC = 0.5 mg/L) applying FDA breakpoints and to amoxicillin/clavulanic acid (MIC ≤ 2 mg/L), TZP (MIC ≤ 2 mg/L), cefotaxime (MIC = 0.12 mg/L), ceftazidime (MIC = 0.25 mg/L), cefepime (MIC = 0.06 mg/L), imipenem (MIC ≤ 0.25 mg/L), meropenem (MIC ≤ 0.12 mg/L) and levofloxacin (MIC = 0.06 mg/L) applying EUCAST and CLSI breakpoints. b

In the absence of CLSI breakpoints, FDA breakpoints were applied.

c

MIC range tested for TZP does not allow differentiation between the CLSI intermediate (I) and resistant (R) categories.

6 Page 37 of 41

ip t

Includes Klebsiella pneumoniae (n = 82), Klebsiella oxytoca (n = 19), Raoultella ornithinolytica (n = 2) and Raoultella

cr

d

us

planticola (n = 1). Includes K. pneumoniae (n = 14) and K. oxytoca (n = 2).

f

Includes Enterobacter cloacae (n = 43), Enterobacter aerogenes (n = 24), Enterobacter kobei (n = 2) and Enterobacter

M an

e

asburiae (n = 1). g

Includes E. cloacae (n = 9), E. aerogenes (n = 10) and E. kobei (n = 1).

h

Includes Proteus mirabilis (n = 28), Proteus vulgaris (n = 6), Proteus penneri (n = 1) and Providencia rettgeri (n = 1).

ce pt

ed

Includes Citrobacter freundii (n = 8), Citrobacter koseri (n = 3) and Citrobacter braakii (n = 1).

Ac

i

7 Page 38 of 41

ip t cr

Table 3

a

us

Cumulative minimum inhibitory concentration (MIC) distributions of ceftolozane/tazobactam against Enterobacteriaceae by resistance phenotype

Organism/major phenotypes (no. tested) Cumulative percentage inhibited at ceftolozane/tazobactam MIC (mg/L) of: All Escherichia coli (250)

1

2

98

100

M an

≤0.03 0.06 0.12 0.25 0.5

8

16

32

64

>64

99.6 100

100

100

100

100

100

100

100

100

100

100

100

100

100

0.4

10

WT phenotype (93)

0.0

1.1

20.4 90.3 100

ESBL phenotype (30)

0.0

0.0

0.0

40.0 66.7 90.0 100

100

100

100

100

100

AmpC-like phenotype (6)

0.0

0.0

0.0

16.7 33.3 66.7 83.3 100.0 100

100

100

100

100

0.0

0.0

5.0

75.2 99.2 100

100

100

100

100

0.0

6.7

58.6 79.8 84.6 86.5 91.3

93.2 96.1 96.1 97.1 100

0.0

9.7

77.8 98.6 100

100

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

b

All Klebsiella spp. (104)

0.0 0.0

ESBL phenotype (16)

0.0

100

100

100

100

100

12.5 31.3 43.8 75.0

87.5 100

100

100

100

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

25.0 100

0.0

0.0

0.0

0.0

0.0

0.0

0.0

100

100

100

100

0.0

0.0

45.5 90.9 100

100

100

100

100

100

100

100

0.0

0.0

2.8

5.6

75.0 100

100

100

100

100

100

100

100

0.0

0.0

0.0

4.2

83.3 100

100

100

100

100

100

100

100

AmpC-like phenotype (1)

0.0

0.0

0.0

0.0

0.0

100

100

100

100

100

100

100

100

b

0.0

0.0

9.0

9.0

63.6 100

100

100

100

100

100

100

100

0.0

1.4

1.4

38

70

95.7 97.1 98.5 100

100

0.0

2.1

2.1

55.3 97.9 100

100

100

Carbapenemase phenotype (4) AmpC-like phenotype (1) Others (11) b WT phenotype (24) Others (11)

Ac

All Proteus spp. (36)

All Enterobacter spp. (70) WT phenotype (47)

100

100

100

ce pt

WT phenotype (72)

ed

0.0

Others (121)

75.2 94

4

100

81.4 87.1 92.8 100

100

100

100

100

1

Page 39 of 41

ip t

1

2

4

8

ESBL phenotype (3)

0.0

0.0

0.0

0.0

0.0

0.0

0.0

33.3

66.7 66.7 66.7 100

100

AmpC hyperproduction (20)

0.0

0.0

0.0

5.0

15.0 50.0 70.0 85.0

90.0 95.0 100

100

100

All Serratia marcescens (17)

0.0

0.0

0.0

0.0

58.8 94.1 100

100

100

100

100

100

100

WT phenotype (16)

0.0

0.0

0.0

0.0

62.5 100

100

100

100

100

100

100

100

AmpC hyperproduction (1)

0.0

0.0

0.0

0.0

0.0

100

100

100

100

100

100

100

0.0

0.0

0.0

50.0 75.0 83.3 83.3 83.3

91.6 91.6 91.6 91.6 100

WT phenotype (9)

0.0

0.0

0.0

66.7 100

100

100

100

100

100

100

100

AmpC hyperproduction (2)

0.0

0.0

0.0

0.0

0.0

50.0 50.0 50.0

100

100

100

100

100

Carbapenemase phenotype (1)

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

100

0.0

0.0

50.0 100

100

100

100

100

100

100

100

100

0.0

0.0

50.0 100

100

100

100

100

100

100

100

100

0.0

0.0

50.0 100

100

100

100

100

100

100

100

100

0.0

0.0

0.0

100

100

100

100

100

100

100

100

All Morganella morganii (10)

0.0 0.0

AmpC hyperproduction (4)

0.0

Salmonella enterica (1)

M an

ce pt

WT phenotype (6)

ed

All Citrobacter spp. (12)

0.0

us

≤0.03 0.06 0.12 0.25 0.5

cr

Organism/major phenotypes (no. tested) Cumulative percentage inhibited at ceftolozane/tazobactam MIC (mg/L) of:

100

0.0

100

16

32

64

>64

WT, wild type; ESBL, extended-spectrum β-lactamase.

MIC50 values are underlined and MIC90 values are shaded in grey; these values are not calculated when the number of isolates is <10.

b

Includes plasmid penicillinases (i.e. TEM-1, OXA-1, IRT enzymes) and/or potential association with porin deficiency.

Ac

a

2

Page 40 of 41

1

Page 41 of 41

d

te

Ac ce p us

an

M

cr

ip t