Bloodstream Infections by Extended-Spectrum β-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae in Children: Epidemiology and Clinical Outcome

ABSTRACT To determine the epidemiologic features and clinical outcomes of bloodstream infections caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolates, cases of bacteremia caused by these organisms in children were analyzed retrospectively. Among the 157 blood isolates recovered from 1993 to 1998 at the Seoul National University Children's Hospital, the prevalence of ESBL production was 17.9% among the E. coli isolates and 52.9% among the K. pneumoniae isolates. The commonest ESBLs were SHV-2a and TEM-52. A novel ESBL, TEM-88, was identified. Pulsed-field gel electrophoresis analysis of the ESBL-producing organisms showed extensive diversity in clonality. The medical records of 142 episodes were reviewed. The risk factors for bloodstream infection with ESBL-producing organisms were prior hospitalization, prior use of oxyimino-cephalosporins, and admission to an intensive care unit within the previous month. There was no difference in clinical severity between patients infected with ESBL-producing strains (the ESBL group) and those infected with ESBL-nonproducing strains (the non-ESBL group) at the time of presentation. However, the overall fatality rate for the ESBL group was significantly higher than that for the non-ESBL group: 12 of 45 (26.7%) versus 5 of 87 (5.7%) (P = 0.001). In a subset analysis of patients treated with extended-spectrum cephalosporins with or without an aminoglycoside, favorable response rates were significantly higher in the non-ESBL group at the 3rd day (6 of 17 versus 33 of 51; P = 0.035), the 5th day (6 of 17 versus 36 of 50; P < 0.05), and the end of therapy (9 of 17 versus 47 of 50; P < 0.001). In conclusion, the ESBL production of the infecting organisms has a significant impact on the clinical course and survival of pediatric patients with bacteremia caused by E. coli and K. pneumoniae.

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Risk factors for and mortality of extended-spectrum-β-lactamase-producing Klebsiella pneumoniae and Escherichia coli nosocomial bloodstream infections

Revista do Instituto de Medicina Tropical de São Paulo ◽

10.1590/s0036-46652009000400006 ◽

2009 ◽

Vol 51 (4) ◽

pp. 211-216 ◽

Cited By ~ 16

Author(s):

Silvana Vargas Superti ◽

Gustavo Augusti ◽

Alexandre Prehn Zavascki

Keyword(s):

Risk Factors ◽

Escherichia Coli ◽

Risk Factor ◽

Klebsiella Pneumoniae ◽

Bloodstream Infections ◽

Blood Cultures ◽

Esbl Production ◽

E Coli ◽

Extended Spectrum ◽

Esbl Producers

A case-control study, involving patients with positive blood cultures for Klebsiella pneumoniae (KP) or Escherichia coli (EC) EC and controls with positive blood cultures for non-ESBL-KP or EC, was performed to assess risk factors for extended-spectrum-β-lactamase (ESBL) production from nosocomial bloodstream infections (BSIs). Mortality among patients with BSIs was also assessed. The study included 145 patients (81, 59.5% with K. pneumoniae and 64, 44.1% with E. coli BSI); 51 (35.2%) isolates were ESBL producers and 94 (64.8%) nonproducers. Forty-five (55.6%) K. pneumoniae isolates were ESBL producers, while only six (9.4%) E. coli isolates produced the enzyme. Multivariate analysis showed that recent exposure to piperacillin-tazobactam (adjusted Odds Ratio [aOR] 6.2; 95%CI 1.1-34.7) was a risk factor for ESBL BSI. K. pneumoniae was significantly more likely to be an ESBL-producing isolate than E. coli (aOR 6.7; 95%CI 2.3-20.2). No cephalosporin class was independently associated with ESBLs BSI; however, in a secondary model considering all oxymino-cephalosporins as a single variable, a significant association was demonstrated (aOR 3.7; 95%CI 1.3-10.8). Overall 60-day mortality was significantly higher among ESBL-producing organisms. The finding that piperacillin-tazobactam use is a risk factor for ESBL-production in KP or EC BSIs requires attention, since this drug can be recommended to limit the use of third-generation cephalosporins.

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Bloodstream Infections Due to Extended-Spectrum β-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae: Risk Factors for Mortality and Treatment Outcome, with Special Emphasis on Antimicrobial Therapy

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.48.12.4574-4581.2004 ◽

2004 ◽

Vol 48 (12) ◽

pp. 4574-4581 ◽

Cited By ~ 180

Author(s):

Cheol-In Kang ◽

Sung-Han Kim ◽

Wan Beom Park ◽

Ki-Deok Lee ◽

Hong-Bin Kim ◽

...

Keyword(s):

Risk Factors ◽

Escherichia Coli ◽

Treatment Outcome ◽

Klebsiella Pneumoniae ◽

Antimicrobial Therapy ◽

Bloodstream Infections ◽

Extended Spectrum Beta Lactamase ◽

E Coli ◽

Extended Spectrum ◽

Empirical Antimicrobial Therapy

ABSTRACT This study was conducted to evaluate risk factors for mortality and treatment outcome of bloodstream infections due to extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EK). ESBL production in stored K. pneumoniae and E. coli blood isolates from Jan 1998 to Dec 2002 was phenotypically determined according to NCCLS guidelines and/or the double-disk synergy test. A total of 133 patients with ESBL-EK bacteremia, including 66 patients with ESBL-producing K. pneumoniae and 67 with ESBL-producing E. coli, were enrolled. The overall 30-day mortality rate was 25.6% (34 of 133). Independent risk factors for mortality were severe sepsis, peritonitis, neutropenia, increasing Acute Physiology and Chronic Health Evaluation II score, and administration of broad-spectrum cephalosporin as definitive antimicrobial therapy (P < 0.05 for each of these risk factors). In 117 of the 133 patients, excluding 16 patients who died within 3 days after blood culture sample acquisition, the 30-day mortality rates according to definitive antibiotics were as follows: carbapenem, 12.9% (8 of 62); ciprofloxacin, 10.3% (3 of 29); and others, such as cephalosporin or an aminoglycoside, 26.9% (7 of 26). When patients who received appropriate definitive antibiotics, such as carbapenem or ciprofloxacin, were evaluated, mortality in patients receiving inappropriate empirical antimicrobial therapy was found not to be significantly higher than mortality in those receiving appropriate empirical antimicrobial therapy (18.9 versus 15.5%; P = 0.666). Carbapenem and ciprofloxacin were the most effective antibiotics in antimicrobial therapy for ESBL-EK bacteremia. A delay in appropriate definitive antimicrobial therapy was not associated with higher mortality if antimicrobial therapy was adjusted appropriately according to the susceptibility results. Our data suggest that more prudent use of carbapenem as empirical antibiotic may be reasonable.

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Costs of Bloodstream Infections Caused by Escherichia coli and Influence of Extended-Spectrum-β-Lactamase Production and Inadequate Initial Antibiotic Therapy

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00143-10 ◽

2010 ◽

Vol 54 (10) ◽

pp. 4085-4091 ◽

Cited By ~ 112

Author(s):

Mario Tumbarello ◽

Teresa Spanu ◽

Rossella Di Bidino ◽

Marco Marchetti ◽

Matteo Ruggeri ◽

...

Keyword(s):

Escherichia Coli ◽

Hospital Costs ◽

Bloodstream Infections ◽

Antimicrobial Treatment ◽

Accounting System ◽

Esbl Production ◽

E Coli ◽

Extended Spectrum ◽

Hospital Stays

ABSTRACT Escherichia coli is the leading cause of bloodstream infections (BSIs) caused by Gram-negative bacteria. The increasing prevalence of antibiotic-resistant E. coli strains, particularly those producing extended-spectrum β-lactamases (ESBLs), increases the odds that empirically prescribed antimicrobial therapy for these infections will be inadequate, but the economic impact of this risk has not been fully evaluated. In the present retrospective 1-year analysis of 134 consecutive E. coli BSIs in our hospital, we explored the clinical and economic impacts of (i) inadequate initial antimicrobial treatment (IIAT) (i.e., empirical treatment with drugs to which the isolate had displayed in vitro resistance) of these infections and (ii) ESBL production by the bloodstream isolate. Cost data were obtained from the hospital accounting system. Compared with the 107 (79.8%) adequately treated patients, the 27 (20.1%) who received IIAT had a higher proportion of ESBL BSIs (74.0% versus 15.8%), longer (+6 days) and more costly (+EUR 4,322.00) post-BSI-onset hospital stays, and higher 21-day mortality rates (40.7% versus 5.6%). Compared with the 97 non-ESBL infections, the 37 (27.6%) ESBL BSIs were also associated with longer (+7 days) and more costly (+EUR 5,026.00) post-BSI-onset hospital stays and increased 21-day mortality (29.7% versus 6.1%). These findings confirm that the hospital costs and mortality associated with E. coli BSIs are significantly increased by ESBL production and by IIAT.

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Frequency and Antimicrobial Sensitivity Pattern of Extended Spectrum β-Lactamases Producing Escherichia coli and Klebsiella pneumoniae Isolated from urine at a Tertiary Care Hospital

Journal of Shaheed Suhrawardy Medical College ◽

10.3329/jssmc.v4i1.11999 ◽

2012 ◽

Vol 4 (1) ◽

pp. 22-25 ◽

Cited By ~ 1

Author(s):

MB Islam ◽

ST Jhora ◽

MA Yusuf ◽

AFMA Sattar ◽

S Shahidullah ◽

...

Keyword(s):

Escherichia Coli ◽

Klebsiella Pneumoniae ◽

Urine Samples ◽

Disk Diffusion ◽

Esbl Production ◽

Klebsiella Species ◽

E Coli ◽

Antimicrobial Sensitivity ◽

Extended Spectrum ◽

Sensitivity Pattern

Background: Infections due to extended spectrum ?-lactamases (ESBL) producing Escherichia coli and Klebsiella pneumoniae have become an important clinical problem. These organisms are important regarding the infection control by the physicians. Objective: The present study was undertaken to determine the prevalence of ESBLs along with their antimicrobial sensitivity pattern in Escherichia coli and Klebsiella pneumoniae. Methodology: This cross sectional study was conducted in the Department of Microbiology at Sir Salimullah Medical College, Dhaka. Urine samples were collected from patients who were clinically suspected to have UTI. After incubation, plates were checked for presence of suspected pathogens. Organisms were identified to species level by conventional methods. All isolated E. coli and K. pneumoniae were included in the study. The susceptibility to antibiotics was determined by Kirby Bauer method on Muller Hinton agar. Isolates were screened for ESBL production by using disk diffusion of cefotaxime, ceftazidime, ceftriaxone and cefpodoxime placed on inoculated plates containing Muller Hinton agar according to the CLSI recommendations. Phenotypic confirmatory test for ESBL producers was done by combined disc diffusion for all the isolates that were screened positive for the ESBL production following CLSI guidelines. Combined disk diffusion method was also done in this study. Result: A total of 220 non repeated urine samples were cultured of which 132(60%) cases had shown the bacterial growth. Among the 132 samples Escherichia coli had found in 103(78.0%) cases and Klebsiella spp. was found in 14(10.6%) cases. Out of 103 E coli 23(22.3%) cases was found as ESBL strain. On the other hand within 14 Klebsiella species, the ESBL strain was found in 5(35.7%) cases. Both E coli and Klebsiella species were 100% sensitive to imipenem. However, cephamycin was sensitive in 93.7% and 100% in E coli and Klebsiella species respectively. Conclusion: Results indicate that routine ESBL detection should be made imperative and empirical use of third generation cephalosporins must be discouraged. DOI: http://dx.doi.org/10.3329/jssmc.v4i1.11999 J Shaheed Suhrawardy Med Coll, 2012;4(1):22-25

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Prevalence and Characterization of Extended-Spectrum β-Lactamase-Producing Antibiotic-Resistant Escherichia coli and Klebsiella pneumoniae in Ready-to-Eat Street Foods

Antibiotics ◽

10.3390/antibiotics10070850 ◽

2021 ◽

Vol 10 (7) ◽

pp. 850

Author(s):

Shobha Giri ◽

Vaishnavi Kudva ◽

Kalidas Shetty ◽

Veena Shetty

Keyword(s):

Escherichia Coli ◽

Food Safety ◽

Klebsiella Pneumoniae ◽

Rural Areas ◽

Significant Risk ◽

Microbiological Quality ◽

Resistant Bacteria ◽

Antibiotic Resistant ◽

E Coli ◽

Extended Spectrum

As the global urban populations increase with rapid migration from rural areas, ready-to-eat (RTE) street foods are posing food safety challenges where street foods are prepared with less structured food safety guidelines in small and roadside outlets. The increased presence of extended-spectrum-β-lactamase (ESBL) producing bacteria in street foods is a significant risk for human health because of its epidemiological significance. Escherichia coli and Klebsiella pneumoniae have become important and dangerous foodborne pathogens globally for their relevance to antibiotic resistance. The present study was undertaken to evaluate the potential burden of antibiotic-resistant E. coli and K. pneumoniae contaminating RTE street foods and to assess the microbiological quality of foods in a typical emerging and growing urban suburb of India where RTE street foods are rapidly establishing with public health implications. A total of 100 RTE food samples were collected of which, 22.88% were E. coli and 27.12% K. pneumoniae. The prevalence of ESBL-producing E. coli and K. pneumoniae was 25.42%, isolated mostly from chutneys, salads, paani puri, and chicken. Antimicrobial resistance was observed towards cefepime (72.9%), imipenem (55.9%), cefotaxime (52.5%), and meropenem (16.9%) with 86.44% of the isolates with MAR index above 0.22. Among β-lactamase encoding genes, blaTEM (40.68%) was the most prevalent followed by blaCTX (32.20%) and blaSHV (10.17%). blaNDM gene was detected in 20.34% of the isolates. This study indicated that contaminated RTE street foods present health risks to consumers and there is a high potential of transferring multi-drug-resistant bacteria from foods to humans and from person to person as pathogens or as commensal residents of the human gut leading to challenges for subsequent therapeutic treatments.

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Incidence and Antimicrobial Susceptibility of Escherichia coli and Klebsiella pneumoniae with Extended-Spectrum β-Lactamases in Community- and Hospital-Associated Intra-Abdominal Infections in Europe: Results of the 2008 Study for Monitoring Antimicrobial Resistance Trends (SMART)

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00265-10 ◽

2010 ◽

Vol 54 (7) ◽

pp. 3043-3046 ◽

Cited By ~ 58

Author(s):

Stephen P. Hawser ◽

Samuel K. Bouchillon ◽

Daryl J. Hoban ◽

Robert E. Badal ◽

Rafael Cantón ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Resistance ◽

Klebsiella Pneumoniae ◽

Antimicrobial Susceptibility ◽

Beta Lactamase ◽

Extended Spectrum Beta Lactamase ◽

E Coli ◽

Extended Spectrum ◽

Abdominal Infections

ABSTRACT From 2002 to 2008, there was a significant increase in extended-spectrum beta-lactamase (ESBL)-positive Escherichia coli isolates in European intra-abdominal infections, from 4.3% in 2002 to 11.8% in 2008 (P < 0.001), but not for ESBL-positive Klebsiella pneumoniae isolates (16.4% to 17.9% [P > 0.05]). Hospital-associated isolates were more common than community-associated isolates, at 14.0% versus 6.5%, respectively, for E. coli (P < 0.001) and 20.9% versus 5.3%, respectively, for K. pneumoniae (P < 0.01). Carbapenems were consistently the most active drugs tested.

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Impact of Extended-Spectrum β-Lactamase Production on Treatment Outcomes of Acute Pyelonephritis Caused by Escherichia coli in Patients without Health Care-Associated Risk Factors

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.04821-14 ◽

2015 ◽

Vol 59 (4) ◽

pp. 1962-1968 ◽

Cited By ~ 13

Author(s):

Sun Hee Park ◽

Su-Mi Choi ◽

Dong-Gun Lee ◽

Sung-Yeon Cho ◽

Hyo-Jin Lee ◽

...

Keyword(s):

Risk Factors ◽

Escherichia Coli ◽

Health Care ◽

Treatment Outcomes ◽

Acute Pyelonephritis ◽

Esbl Production ◽

Content Type ◽

E Coli ◽

Extended Spectrum ◽

The Impact

ABSTRACTExtended-spectrum β-lactamase-producingEscherichia coli(ESBL-EC) is increasingly identified as a cause of acute pyelonephritis (APN) among patients without recent health care contact, i.e., community-associated APN. This case-control study compared 75 cases of community-associated ESBL-EC APN (CA-ESBL) to 225 controls of community-associated non-ESBL-EC APN (CA-non-ESBL) to identify the risk factors for ESBL-EC acquisition and investigate the impact of ESBL on the treatment outcomes of community-associated APN (CA-APN) caused byE. coliat a Korean hospital during 2007 to 2013. The baseline characteristics were similar between the cases and controls; the risk factors for ESBL-EC were age (>55 years), antibiotic use within the previous year, and diabetes with recurrent APN. The severity of illness did not differ between CA-ESBL and CA-non-ESBL (Acute Physiology and Chronic Health Evaluation [APACHE] II scores [mean ± standard deviation], 7.7 ± 5.9 versus 6.4 ± 5.3;P= 0.071). The proportions of clinical (odds ratio [OR], 1.76; 95% confidence interval [CI], 0.57 to 5.38;P= 0.323) and microbiological (OR, 1.16; 95% CI, 0.51 to 2.65;P= 0.730) cures were similar, although the CA-ESBL APN patients were less likely to receive appropriate antibiotics within 48 h. A multivariable Cox proportional hazards analysis of the prognostic factors for CA-APN caused byE. colishowed that ESBL production was not a significant factor for clinical (hazard ratio [HR], 0.39; 95% CI, 0.12 to 1.30;P= 0.126) or microbiological (HR, 0.49; 95% CI, 0.21 to 1.12;P= 0.091) failure. The estimates did not change after incorporating weights calculated using propensity scores for acquiring ESBL-EC. Therefore, ESBL production did not negatively affect treatment outcomes among patients with community-associatedE. coliAPN.

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Extraintestinal pathogenic Escherichia coli in Saudi Arabia: A review of antimicrobial resistance and molecular epidemiology

Tropical Journal of Pharmaceutical Research ◽

10.4314/tjpr.v19i2.30 ◽

2020 ◽

Vol 19 (2) ◽

pp. 447-453

Author(s):

Abdulaziz Alqasim

Keyword(s):

Escherichia Coli ◽

Saudi Arabia ◽

Antimicrobial Resistance ◽

Molecular Epidemiology ◽

Bloodstream Infections ◽

Epidemiological Studies ◽

Colistin Resistance ◽

E Coli ◽

Extended Spectrum ◽

Pathogenic Escherichia Coli

Extra-intestinal pathogenic Escherichia coli (ExPEC) is commonly associated with causing urinary tract and bloodstream infections. Over the past two decades, the antimicrobial resistance of ExPEC has increasingly been reported [1]. Given that Saudi Arabia annually hosts mass religious events, such as Hajj, this review investigated several aspects of antimicrobial resistance of ExPEC in this country including the current prevalence of resistance and molecular epidemiology of ExPEC isolates. Generally, the overall prevalence of antibiotic resistance of ExPEC in Saudi Arabia is on increase. The current emergence of colistin resistance in ExPEC represents a major challenge to public health. Local molecular epidemiological studies have shown the dominance of E. coli sequence type 131 (E. coli ST131) over other major ExPEC STs. This is an important observation given that this clone has been associated with high multidrug resistance and extended-spectrum β-lactamases carriage. To reduce the burden of this resistance in the future, it would be crucial to avoid uncontrolled use of antibiotics in either clinical settings or animal food industry. Keywords: Extra-intestinal pathogenic Escherichia coli, Antimicrobial resistance, ST131, Saudi Arabia, Colistin resistance, Extended-spectrum β-lactamases

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Outcome of community-onset ESBL-producing Escherichia coli and Klebsiella pneumoniae bacteraemia and urinary tract infection: a population-based cohort study in Denmark

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa361 ◽

2020 ◽

Vol 75 (12) ◽

pp. 3656-3664

Author(s):

Rasmus Richelsen ◽

Jesper Smit ◽

Henrik Carl Schønheyder ◽

Pavithra Laxsen Anru ◽

Belen Gutiérrez-Gutiérrez ◽

...

Keyword(s):

Escherichia Coli ◽

Urinary Tract Infection ◽

Cohort Study ◽

Urinary Tract ◽

Tract Infection ◽

Klebsiella Pneumoniae ◽

Population Based ◽

Esbl Production ◽

E Coli ◽

Community Onset

Abstract Objectives To assess the impact of ESBL production on mortality and length of hospital stay (LOS) of community-onset infections due to Escherichia coli or Klebsiella pneumoniae. Methods A population-based cohort study including all adult patients hospitalized with a first-time community-onset E. coli or K. pneumoniae bacteraemia or urinary tract infection in the North Denmark Region between 2007 and 2017. For each bacterial agent, we computed 1 year Kaplan–Meier survival curves and cumulative incidence functions of LOS, and by use of Cox proportional hazard regression we computed HRs as estimates of 30 day and 1 year mortality rate ratios (MRRs) and LOS among patients with and without ESBL-producing infections. Results We included 24 518 cases (among 22350 unique patients), of whom 1018 (4.2%) were infected by an ESBL-producing bacterium. The 30 day cumulative mortality and adjusted MRR (aMRR) in patients with and without ESBL-producing isolates was as follows: E. coli bacteraemia (n = 3831), 15.8% versus 14.0%, aMRR = 1.01 (95% CI = 0.70–1.45); E. coli urinary tract infection (n = 17151), 9.5% versus 8.7%, aMRR = 0.97 (95% CI = 0.75–1.26); K. pneumoniae bacteraemia (n = 734), 0% versus 17.2%, aMRR = not applicable; and K. pneumoniae urinary tract infection (n = 2802), 13.8% versus 10.7%, aMRR = 1.13 (95% CI = 0.73–1.75). The 1 year aMRR remained roughly unchanged. ESBL-producing E. coli bacteraemia was associated with an increased LOS compared with non-ESBL production. Conclusions ESBL production was not associated with an increased short- or long-term mortality in community-onset infections due to E. coli or K. pneumoniae, yet ESBL-producing E. coli bacteraemia was associated with an increased LOS.

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Carbapenem Therapy for Bacteremia Due to Extended-Spectrum-β-Lactamase-Producing Escherichia coli or Klebsiella pneumoniae: Implications of Ertapenem Susceptibility

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.06301-11 ◽

2012 ◽

Vol 56 (6) ◽

pp. 2888-2893 ◽

Cited By ~ 24

Author(s):

Nan-Yao Lee ◽

Ching-Chi Lee ◽

Wei-Han Huang ◽

Ko-Chung Tsui ◽

Po-Ren Hsueh ◽

...

Keyword(s):

Risk Factors ◽

Escherichia Coli ◽

Klebsiella Pneumoniae ◽

Content Type ◽

Extended Spectrum Beta Lactamase ◽

E Coli ◽

Medical Centers ◽

Extended Spectrum ◽

Appropriate Therapy ◽

Related Mortality

ABSTRACTA retrospective study was conducted at two medical centers in Taiwan to evaluate the clinical characteristics, outcomes, and risk factors for mortality among patients treated with a carbapenem for bacteremia caused by extended-spectrum-beta-lactamase (ESBL)-producing organisms. A total of 251 patients with bacteremia caused by ESBL-producingEscherichia coliandKlebsiella pneumoniaeisolates treated by a carbapenem were identified. Among these ESBL-producing isolates, rates of susceptibility to ertapenem (MICs ≤ 0.25 μg/ml) were 83.8% and 76.4%, respectively; those to meropenem were 100% and 99.3%, respectively; and those to imipenem were 100% and 97.9%, respectively. There were no significant differences in the critical illness rate (P= 0.1) or sepsis-related mortality rate (P= 0.2) for patients with bacteremia caused by ESBL-producingK. pneumoniae(140 isolates, 55.8%) andE. coli(111 isolates, 44.2%). Multivariate analysis of variables related to sepsis-related mortality revealed that the presence of severe sepsis (odds ratio [OR], 15.9; 95% confidence interval [CI], 5.84 to 43.34;P< 0.001), hospital-onset bacteremia (OR, 4.65; 95% CI, 1.42 to 15.24;P= 0.01), and ertapenem-nonsusceptible isolates (OR, 5.12; 95% CI, 2.04 to 12.88;P= 0.001) were independent risk factors. The patients receiving inappropriate therapy had a higher sepsis-related mortality than those with appropriate therapy (P= 0.002), irrespective of ertapenem, imipenem, or meropenem therapy. Infections due to the ertapenem-susceptible isolates (MICs ≤ 0.25 μg/ml) were associated with a more favorable outcome than those due to ertapenem-nonsusceptible isolates (MICs > 0.25 μg/ml), if treated by a carbapenem. However, the mortality for patients with bacteremic episodes due to isolates with MICs of ≤0.5 μg/ml was similar to the mortality for those whose isolates had MICs of >0.5 μg/ml (P= 0.8). Such a finding supports the rationale of the current CLSI 2011 criteria for carbapenems forEnterobacteriaceae.

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