Clonal Structure, Extended-Spectrum β-Lactamases, and Acquired AmpC-Type Cephalosporinases of Escherichia coli Populations Colonizing Patients in Rehabilitation Centers in Four Countries

ABSTRACTThe prospective project MOSAR was conducted in five rehabilitation units: the Berck Maritime Hôpital (Berck, France), Fondazione Santa Lucia (Rome, Italy), Guttmann Institute (GI; Barcelona, Spain), and Loewenstein Hospital and Tel-Aviv Souraski Medical Center (TA) (Tel-Aviv, Israel). Patients were screened for carriage ofEnterobacteriaceaeresistant to expanded-spectrum cephalosporins (ESCs) from admission until discharge. The aim of this study was to characterize the clonal structure, extended-spectrum β-lactamases (ESBLs), and acquired AmpC-like cephalosporinases in theEscherichia colipopulations collected. A total of 376 isolates were randomly selected. The overall number of sequence types (STs) was 76, including 7 STs that grouped at least 10 isolates from at least three centers each, namely, STs 10, 38, 69, 131, 405, 410, and 648. These clones comprised 65.2% of all isolates, and ST131 alone comprised 41.2%. Of 54 STs observed only in one center, some STs played a locally significant role, like ST156 and ST393 in GI or ST372 and ST398 in TA. Among 16 new STs, five arose from evolution within the ST10 and ST131 clonal complexes. ESBLs and AmpCs accounted for 94.7% and 5.6% of the ESC-hydrolyzing β-lactamases, respectively, being dominated by the CTX-M-like enzymes (79.9%), followed by the SHV (13.5%) and CMY-2 (5.3%) types. CTX-M-15 was the most prevalent β-lactamase overall (40.6%); other ubiquitous enzymes were CTX-M-14 and CMY-2. Almost none of the common clones correlated strictly with one β-lactamase; although 58.7% of ST131 isolates produced CTX-M-15, the clone also expressed nine other enzymes. A number of clone variants with specific pulsed-field gel electrophoresis and ESBL types were spread in some locales, potentially representing newly emergingE. coliepidemic strains.

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Clinical Epidemiology and Molecular Analysis of Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Nepal: Characteristics of Sequence Types 131 and 648

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00270-15 ◽

2015 ◽

Vol 59 (6) ◽

pp. 3424-3432 ◽

Cited By ~ 24

Author(s):

Jatan Bahadur Sherchan ◽

Kayoko Hayakawa ◽

Tohru Miyoshi-Akiyama ◽

Norio Ohmagari ◽

Teruo Kirikae ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Genes ◽

Clinical Epidemiology ◽

University Teaching ◽

Drug Resistant ◽

Content Type ◽

Acquired Drug Resistance ◽

E Coli ◽

Extended Spectrum ◽

Sequence Types

ABSTRACTRecently, CTX-M-type extended-spectrum-β-lactamase (ESBL)-producingEscherichia colistrains have emerged worldwide. In particular,E. coliwith O antigen type 25 (O25) and sequence type 131 (ST131), which is often associated with the CTX-M-15 ESBL, has been increasingly reported globally; however, epidemiology reports on ESBL-producingE. coliin Asia are limited. Patients with clinical isolates of ESBL-producingE. coliin the Tribhuvan University teaching hospital in Kathmandu, Nepal, were included in this study. Whole-genome sequencing of the isolates was conducted to analyze multilocus sequence types, phylotypes, virulence genotypes, O25b-ST131 clones, and distribution of acquired drug resistance genes. During the study period, 105 patients with ESBL-producingE. coliisolation were identified, and the majority (90%) of these isolates were CTX-M-15 positive. The most dominant ST was ST131 (n= 54; 51.4%), followed by ST648 (n= 15; 14.3%). All ST131 isolates were identified as O25b-ST131 clones, subclone H30-Rx. Three ST groups (ST131, ST648, and non-ST131/648) were compared in further analyses. ST648 isolates had a proportionally higher resistance to non-β-lactam antibiotics and featured drug-resistant genes more frequently than ST131 or non-ST131/648 isolates. ST131 possessed the most virulence genes, followed by ST648. The clinical characteristics were similar among groups. More than 38% of ESBL-producingE. coliisolates were from the outpatient clinic, and pregnant patients comprised 24% of ESBL-producingE. colicases. We revealed that the high resistance of ESBL-producingE. colito multiple classes of antibiotics in Nepal is driven mainly by CTX-M-producing ST131 and ST648. Their immense prevalence in the communities is a matter of great concern.

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Epidemiology and Risk Factors for Isolation of Escherichia coli Producing CTX-M-Type Extended-Spectrum β-Lactamase in a Large U.S. Medical Center

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02516-12 ◽

2013 ◽

Vol 57 (8) ◽

pp. 4010-4018 ◽

Cited By ~ 45

Author(s):

Kayoko Hayakawa ◽

Sureka Gattu ◽

Dror Marchaim ◽

Ashish Bhargava ◽

Mohan Palla ◽

...

Keyword(s):

Risk Factors ◽

Escherichia Coli ◽

Medical Center ◽

Antibiotic Use ◽

Content Type ◽

E Coli ◽

H2 Blocker ◽

Extended Spectrum ◽

Independent Risk Factors ◽

Encoding Genes

ABSTRACTA case-case-control study was conducted to identify independent risk factors for recovery ofEscherichia colistrains producing CTX-M-type extended-spectrum β-lactamases (CTX-ME. coli) within a large Southeastern Michigan medical center. Unique cases with isolation of ESBL-producingE. colifrom February 2010 through July 2011 were analyzed by PCR forblaCTX-M,blaTEM, andblaSHVgenes. Patients with CTX-ME. coliwere compared to patients withE. colistrains not producing CTX-M-type ESBLs (non-CTX-ME. coli) and uninfected controls. Of 575 patients with ESBL-producingE. coli, 491 (85.4%) isolates contained a CTX-M ESBL gene. A total of 319 (84.6%) patients with CTX-ME. coli(282 [74.8%] CTX-M-15 type) were compared to 58 (15.4%) non-CTX-ME. colipatients and to uninfected controls. Independent risk factors for CTX-ME. coliisolation compared to non-CTX-ME. coliincluded male gender, impaired consciousness, H2 blocker use, immunosuppression, and exposure to penicillins and/or trimethoprim-sulfamethoxazole. Compared to uninfected controls, independent risk factors for isolation of CTX-ME. coliincluded presence of a urinary catheter, previous urinary tract infection, exposure to oxyimino-cephalosporins, dependent functional status, non-home residence, and multiple comorbid conditions. Within 48 h of admission, community-acquired CTX-ME. coli(n= 51 [16%]) and non-CTX-ME coli(n= 11 [19%]) strains were isolated from patients with no recent health care contacts. CTX-ME. colistrains were more resistant to multiple antibiotics than non-CTX-ME. colistrains. CTX-M-encoding genes, especiallyblaCTX-M-15type, represented the most common ESBL determinants from ESBL-producingE. coli, the majority of which were present upon admission. Septic patients with risk factors for isolation of CTX-ME. colishould be empirically treated with appropriate agents. Regional infection control efforts and judicious antibiotic use are needed to control the spread of these organisms.

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Clinical and Molecular Characteristics of Extended-Spectrum- β-Lactamase-Producing Escherichia coli Causing Bacteremia in the Rotterdam Area, Netherlands

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00074-11 ◽

2011 ◽

Vol 55 (7) ◽

pp. 3576-3578 ◽

Cited By ~ 44

Author(s):

Akke K. van der Bij ◽

Gisele Peirano ◽

Wil H. F. Goessens ◽

Eric R. van der Vorm ◽

M. van Westreenen ◽

...

Keyword(s):

Escherichia Coli ◽

Teaching Hospital ◽

Molecular Characteristics ◽

Community Hospitals ◽

Content Type ◽

E Coli ◽

Extended Spectrum ◽

Abdominal Infections ◽

Sequence Types ◽

Community Onset

ABSTRACTWe investigated the clinical and molecular characteristics of bacteremia caused by extended-spectrum-β-lactamase (ESBL)-producingEscherichia coliover a 2-year period (2008 to 2009) in the Rotterdam region (including 1 teaching hospital and 2 community hospitals) of Netherlands. The majority of patients presented with community onset urinary and intra-abdominal infections, with an increase in prevalence during 2009. The majority ofE. coliisolates produced CTX-M-15, and 4 sequence types (ST38, ST131, ST405, and ST648) predominated. There were significant differences in clinical and molecular characteristics between the 2 community hospitals.

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Repeated Isolation of Extended-Spectrum-β-Lactamase-Positive Escherichia coli Sequence Types 648 and 131 from Community Wastewater Indicates that Sewage Systems Are Important Sources of Emerging Clones of Antibiotic-Resistant Bacteria

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00823-19 ◽

2019 ◽

Vol 63 (9) ◽

Cited By ~ 6

Author(s):

Erik Paulshus ◽

Kaisa Thorell ◽

Jessica Guzman-Otazo ◽

Enrique Joffre ◽

Patricia Colque ◽

...

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Resistant Bacteria ◽

Antibiotic Resistant Bacteria ◽

Antibiotic Resistant ◽

Content Type ◽

E Coli ◽

Extended Spectrum ◽

Pump Station ◽

Sequence Types

ABSTRACT Antibiotic resistance in bacteria is an emerging problem globally. Resistant bacteria are found in human and animal microbiota, as well as in the environment. Wastewater receives bacteria from all these sources and thus can provide a measurement of abundance and diversity of antibiotic-resistant bacteria circulating in communities. In this study, water samples were collected from a wastewater pump station in a Norwegian suburban community over a period of 15 months. A total of 45 daily samples were cultured and analyzed for the presence of Escherichia coli. Eighty E. coli-like colonies were collected from each daily sample and then phenotyped and analyzed for antibiotic resistance using the PhenePlate-AREB system. During the sampling period, two unique E. coli phenotypes with resistance to cefotaxime and cefpodoxime indicating carriage of extended-spectrum β-lactamases (ESBL) were observed repeatedly. Whole-genome sequencing of 15 representative isolates from the two phenotypes identified these as two distinct clones belonging to the two globally spread E. coli multilocus sequence types (STs) ST131 and ST648 and carrying blaCTX-M-15. The number of ESBL-positive E. coli strains in the community wastewater pump station was 314 of 3,123 (10%) analyzed E. coli strains. Of the ESBL-positive isolates, 37% belonged to ST648, and 7% belonged to ST131. Repeated findings of CTX-M-15-positive ST648 and ST131 over time indicate that these STs are resident in the analyzed wastewater systems and/or circulate abundantly in the community.

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Phylogenetic Grouping and Virulence Potential of Extended-Spectrum-β-Lactamase-Producing Escherichia coli Strains in Cattle

Applied and Environmental Microbiology ◽

10.1128/aem.00351-12 ◽

2012 ◽

Vol 78 (13) ◽

pp. 4677-4682 ◽

Cited By ~ 38

Author(s):

Charlotte Valat ◽

Frédéric Auvray ◽

Karine Forest ◽

Véronique Métayer ◽

Emilie Gay ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Determinants ◽

Phylogenetic Groups ◽

Content Type ◽

E Coli ◽

Extended Spectrum ◽

Specific Distribution ◽

Extended Spectrum Beta Lactamases ◽

Phylogenetic Grouping ◽

Almost All

ABSTRACTIn line with recent reports of extended-spectrum beta-lactamases (ESBLs) inEscherichia coliisolates of highly virulent serotypes, such as O104:H4, we investigated the distribution of phylogroups (A, B1, B2, D) and virulence factor (VF)-encoding genes in 204 ESBL-producingE. coliisolates from diarrheic cattle. ESBL genes, VFs, and phylogroups were identified by PCR and a commercial DNA array (Alere, France). ESBL genes belonged mostly to the CTX-M-1 (65.7%) and CTX-M-9 (27.0%) groups, whereas those of the CTX-M-2 and TEM groups were much less represented (3.9% and 3.4%, respectively). One ESBL isolate wasstx1andeaepositive and belonged to a major enterohemorrhagicE. coli(EHEC) serotype (O111:H8). Two other isolates wereeaepositive butstxnegative; one of these had serotype O26:H11. ESBL isolates belonged mainly to phylogroup A (55.4%) and, to lesser extents, to phylogroups D (25.5%) and B1 (15.6%), whereas B2 strains were quasi-absent (1/204). The number of VFs was significantly higher in phylogroup B1 than in phylogroups A (P= 0.04) and D (P= 0.02). Almost all of the VFs detected were found in CTX-M-1 isolates, whereas only 64.3% and 33.3% of them were found in CTX-M-9 and CTX-M-2 isolates, respectively. These results indicated that the widespread dissemination of theblaCTX-Mgenes within theE. colipopulation from cattle still spared the subpopulation of EHEC/Shiga-toxigenicE. coli(STEC) isolates. In contrast to other reports on non-ESBL-producing isolates from domestic animals, B1 was not the main phylogroup identified. However, B1 was found to be the most virulent phylogroup, suggesting host-specific distribution of virulence determinants among phylogenetic groups.

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Competitive Exclusion Reduces Transmission and Excretion of Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Broilers

Applied and Environmental Microbiology ◽

10.1128/aem.03439-16 ◽

2017 ◽

Vol 83 (11) ◽

Cited By ~ 22

Author(s):

Daniela Ceccarelli ◽

Alieda van Essen-Zandbergen ◽

Bregtje Smid ◽

Kees T. Veldman ◽

Gert Jan Boender ◽

...

Keyword(s):

Escherichia Coli ◽

Competitive Exclusion ◽

Intervention Strategy ◽

Substantial Reduction ◽

Poultry Production ◽

Broiler Meat ◽

Content Type ◽

E Coli ◽

Extended Spectrum ◽

Probiotic Product

ABSTRACT Extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases (pAmpC) are enzymes able to hydrolyze a large variety of β-lactam antibiotics, including third-generation cephalosporins and monobactams. Broilers and broiler meat products can be highly contaminated with ESBL- and pAmpC-producing Escherichia coli strains, also known as extended-spectrum cephalosporin (ESC)-resistant E. coli strains, and can be a source for human infections. As few data on interventions to reduce the presence of ESC-resistant E. coli in broilers are available, we used transmission experiments to examine the role of competitive exclusion (CE) on reducing transmission and excretion in broilers. A broiler model to study the transmission of ESC-resistant E. coli was set up. Day-old chickens were challenged with an ESBL-producing E. coli strain isolated from healthy broilers in the Netherlands. Challenged and not challenged chicks were housed together in pairs or in groups, and ESBL-producing E. coli transmission was monitored via selective culturing of cloacal swab specimens. We observed a statistically significant reduction in both the transmission and excretion of ESBL-producing E. coli in chicks treated with the probiotic flora before E. coli challenge compared to the transmission and excretion in untreated controls. In conclusion, our results support the use of competitive exclusion as an intervention strategy to control ESC-resistant E. coli in the field. IMPORTANCE Extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases are a primary cause of resistance to β-lactam antibiotics among members of the family Enterobacteriaceae in humans, animals, and the environment. Food-producing animals are not exempt from this, with a high prevalence being seen in broilers, and there is evidence pointing to a possible foodborne source for human contamination. We investigated the effect of administration of a commercial probiotic product as an intervention to reduce the amount of ESBL-producing Escherichia coli in broilers. Our results showed a substantial reduction in the level of colonization of broiler intestines by ESBL-producing E. coli after administration of commercial probiotic product. The protective effect provided by these probiotics could be implemented on a larger scale in poultry production. Reductions in the levels of ESBL-producing Enterobacteriaceae in the food chain would considerably benefit public health.

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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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Relative Fecal Abundance of Extended-Spectrum-β-Lactamase-Producing Escherichia coli Strains and Their Occurrence in Urinary Tract Infections in Women

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00238-13 ◽

2013 ◽

Vol 57 (9) ◽

pp. 4512-4517 ◽

Cited By ~ 58

Author(s):

Etienne Ruppé ◽

Brandusa Lixandru ◽

Radu Cojocaru ◽

Çağrı Büke ◽

Elisabeth Paramythiotou ◽

...

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Virulence Factors ◽

Urinary Tract Infections ◽

Predictive Values ◽

Content Type ◽

Extended Spectrum Beta Lactamase ◽

E Coli ◽

Extended Spectrum ◽

Tract Infections

ABSTRACTExtended-spectrum-beta-lactamase (ESBL)-producingEscherichia coli(ESBLE. coli) strains are of major concern because few antibiotics remain active against these bacteria. We investigated the association between the fecal relative abundance (RA) of ESBL-producingE. coli(ESBL-RA) and the occurrence of ESBLE. coliurinary tract infections (UTIs). The first stool samples passed after suspicion of UTI from 310 women with subsequently confirmedE. coliUTIs were sampled and tested for ESBL-RA by culture on selective agar. Predictive values of ESBL-RA for ESBLE. coliUTI were analyzed for women who were not exposed to antibiotics when the stool was passed. ESBLE. coliisolates were characterized for ESBL type, phylogroup, relatedness, and virulence factors. The prevalence of ESBLE. colifecal carriage was 20.3%, with ESBLE. coliUTIs being present in 12.3% of the women. The mean ESBL-RA (95% confidence interval [CI]) was 13-fold higher in women exposed to antibiotics at the time of sampling than in those not exposed (14.3% [range, 5.6% to 36.9%] versus 1.1% [range, 0.32% to 3.6%], respectively;P< 0.001) and 18-fold higher in women with ESBLE. coliUTI than in those with anotherE. coliUTI (10.0% [range, 0.54% to 100%] versus 0.56% [range, 0.15% to 2.1%[, respectively;P< 0.05). An ESBL-RA of <0.1% was 100% predictive of a non-ESBLE. coliUTI. ESBL type, phylogroup, relatedness, and virulence factors were not found to be associated with ESBL-RA. In conclusion, ESBL-RA was linked to the occurrence of ESBLE. coliUTI in women who were not exposed to antibiotics and who had the same clone ofE. coliin urine samples and fecal samples. Especially, a low ESBL-RA appeared to be associated with a low risk of ESBLE. coliinfection.

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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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Risk Factors for Infection or Colonization with CTX-M Extended-Spectrum-β-Lactamase-Positive Escherichia coli

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01136-12 ◽

2012 ◽

Vol 56 (11) ◽

pp. 5575-5580 ◽

Cited By ~ 13

Author(s):

Jennifer H. Han ◽

Kei Kasahara ◽

Paul H. Edelstein ◽

Warren B. Bilker ◽

Ebbing Lautenbach

Keyword(s):

Risk Factors ◽

Escherichia Coli ◽

Control Strategies ◽

Content Type ◽

E Coli ◽

Extended Spectrum ◽

Increased Risk ◽

Urinary Culture ◽

Multivariable Analyses ◽

And Control

ABSTRACTThere has been a significant increase in the prevalence ofEnterobacteriaceaethat produce CTX-M-type extended-spectrum β-lactamases. The objective of this study was to evaluate risk factors for infection or colonization with CTX-M-positiveEscherichia coli. A case-control study was conducted within a university system from 1 January 2007 to 31 December 2008. All patients with clinical cultures withE. colidemonstrating resistance to extended-spectrum cephalosporins were included. Case patients were designated as those with cultures positive for CTX-M-positiveE. coli, and control patients were designated as those with non-CTX-M-producingE. coli. Multivariable logistic regression analyses were performed to evaluate risk factors for CTX-M-positive isolates. A total of 83 (56.8%) of a total of 146 patients had cultures with CTX-M-positiveE. coli. On multivariable analyses, there was a significant association between infection or colonization with CTX-M-type β-lactamase-positiveE. coliand receipt of piperacillin-tazobactam in the 30 days prior to the culture date (odds ratio [OR], 7.36; 95% confidence interval [CI], 1.61 to 33.8;P= 0.01) and a urinary culture source (OR, 0.36; 95% CI, 0.17 to 0.77;P= 0.008). The rates of resistance to fluoroquinolones were significantly higher in isolates from case patients than in isolates from control patients (90.4 and 50.8%, respectively;P< 0.001). We found that nonurinary sources of clinical cultures and the recent use of piperacillin-tazobactam conferred an increased risk of colonization or infection with CTX-M-positiveE. coli. Future studies will need to focus on outcomes associated with infections due to CTX-M-positiveE. coli, as well as infection control strategies to limit the spread of these increasingly common organisms.

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