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PubMed2005

beta-Lactamases among extended-spectrum beta-lactamase (ESBL)-resistant Salmonella from poultry, poultry products and human patients in The Netherlands.

OBJECTIVES: The purpose of this work was to study the genetic determinants responsible for extended-spectrum beta-lactamase (ESBL) resistance of Salmonella isolated from Dutch poultry, poultry meat and hospitalized humans. METHODS: Thirty-four ESBL-resistant Salmonella isolates from The Netherlands were tested towards 21 antimicrobial agents. PCR and sequencing were used to determine the underlying genetic determinants responsible for the ESBL phenotypes. The transferability of the ESBL phenotypes was tested by conjugation to a susceptible Salmonella enterica serovar Dublin and plasmid purification, restriction fragment length polymorphism (RFLP) and pulsed-field gel electrophoresis (PFGE) were employed to further characterize a subset of the isolates. RESULTS: A great genetic diversity was seen among the isolates. The bla(TEM-52) gene was most predominant and was found among Salmonella enterica serovars Blockley, Thomson, London, Enteritidis phage type 14b, Paratyphi B, Virchow and Typhimurium phage types 11 and 507. We also found the bla(TEM-20) gene in S. Paratyphi B var. Java and the bla(TEM-63) gene in S. Isangi. Furthermore, we detected the bla(CTX-M-28) gene in S. Isangi and the bla(CTX-M-3) gene in S. Typhimurium phage type 507. The bla(CTX-M-2) gene was identified in S. Virchow, which also contained a copy of the bla(SHV-2) gene and a copy of the bla(TEM-1) gene. The bla(SHV-12) gene was found alone in S. Concord and together with the bla(TEM-52) gene in S. Typhimurium. Finally, the bla(ACC-1) gene was cloned from a S. Bareilly isolate and was found to be present on indistinguishable plasmids in all S. Bareilly isolates examined as well as in a S. Braenderup isolate and a S. Infantis isolate. CONCLUSIONS: Our data underscore the diversity of ESBL genes in Salmonella enterica isolated from animals, food products and human patients.

Animals↗
PubMed2005

CTX-M: changing the face of ESBLs in the UK.

The UK has experienced a sudden rise in extended-spectrum beta-lactamase (ESBL) rates, largely due to the appearance and spread of Escherichia coli producing CTX-M-15 type beta-lactamase. The British Society for Antimicrobial Chemotherapy organized two update meetings during 2004 to report and discuss the recognition, clinical diagnosis, treatment and control of bacteria producing these beta-lactamases. This paper reports the data and reviews made by contributors to the conferences. The historical distribution and emergence of ESBLs was reviewed along with the emergence of plasmid-mediated CTX-M ESBLs following their mobilization from the chromosome of Kluyvera spp. The first significant outbreak of CTX-M producers in the UK occurred in 2001 and involved Klebsiella pneumoniae with CTX-M-26 at one site, but by 2003, cloned and diverse E. coli with CTX-M-15 were widespread, with Shropshire one of the most affected regions. The specific experience in Shropshire was reported on and a comprehensive review made of the level of awareness of the need for ESBL detection in laboratories in England and Wales, together with a description of the variety of methods that may be applied, with recommendations for optimal methodology. The increased mortality associated with inappropriate treatment of infections caused by ESBL-producing strains was highlighted, together with discussion on potential control of cross-infection. The meeting concluded that the CTX-M genes have now become widespread in not only E. coli but other Enterobacteriaceae in the UK and this will represent a substantial threat to both the treatment of infections caused by these bacteria in the community and within hospitals.

Anti-Bacterial Agents↗
PubMed2026

Emergence and persistence of ESBL- and carbapenemase-producing Klebsiella pneumoniae-related species in Barcelona wastewater treatment plants.

The World Health Organization classifies extended-spectrum beta-lactamase (ESBL) and carbapenemase-producing Klebsiella pneumoniae as critical-priority pathogens due to their high incidence, mortality, transmissibility, rapid resistance acquisition, and limited treatment options. Beyond clinical settings, their detection in wastewater treatment plants (WWTPs) provides an opportunity to assess their prevalence, persistence, and circulation within wastewater systems. This study characterized 37 antibiotic-resistant K. pneumoniae-related species strains isolated from two WWTPs in the metropolitan area of Barcelona, analyzing their antimicrobial resistance (AMR) profiles, antimicrobial resistance genes (ARGs), biocide and heavy metal tolerance genes (HMTGs), virulence factor genes (VFGs), biofilm-forming capacity, and conjugation ability. Among them, 70.3% were multidrug-resistant (MDR), and 16.2% were extensively drug-resistant. Whole-genome sequencing revealed diverse ARGs; all strains carried β-lactam resistance genes (14 ESBL and 12 carbapenemase producers), nearly all (96.9%) carried biocide or HMTGs, 64.9% harbored integrases, and all carried VFGs. Core-genome SNP analysis identified closely related strains across sampling periods and treatment stages, suggesting long-term persistence within the wastewater treatment system, despite biological and chemical processes in secondary treatment. Most strains (67.6%) displayed biofilm-forming capacity, and conjugation assays confirmed horizontal gene transfer in five of the seven ESBL-producing strains tested. High-risk clones were predominantly detected in the IFAS secondary treatment stage of the Gavà-Viladecans WWTP. The three strains recovered from the reclaimed water of the Baix Llobregat WWTP were ESBL or carbapenemase producers. Altogether, these results provide genomic and phenotypic evidence of the persistence and circulation of antibiotic-resistant K. pneumoniae-related species within wastewater treatment systems.IMPORTANCEWWTPs are essential for urban sanitation and environmental protection. Understanding how clinically relevant pathogens, such as ESBL and carbapenemase-producing K. pneumoniae-related species strains, behave in these settings may inform public health considerations. Investigating the presence and persistence of high-risk MDR pathogens in WWTPs helps identify circulation of AMR, assess the risk of gene transfer, and evaluate the potential for co-selection with other contaminants. This knowledge supports efforts to improve wastewater treatments, strengthen environmental surveillance, and develop integrated One Health strategies to limit the spread of AMR across human, animal, and environmental sectors.

Wastewater↗
PubMed2005

Emergence and wide dissemination of CTX-M-type ESBLs, and CMY-2- and DHA-1-type AmpC beta-lactamases in Korean respiratory isolates of Klebsiella pneumoniae.

Respiratory isolates of Klebsiella pneumoniae in Korea during 2002-2003 were studied to determine the prevalence and types of extended-spectrum beta-lactamases (ESBLs) and plasmid-mediated AmpC beta-lactamases (PABLs). ESBL-production was tested by double-disk synergy, and genotypes of beta-lactamases were determined by PCR and sequencing. ESBLs were detected in 28.4% of 373 isolates, and the most prevalent types were SHV-12 (63 isolates) and CTX-M-14 (9 isolates). Forty of 75 ESBL-producers (53.5%) also had PABLs: 21 isolates with CMY-2-like, 17 with DHA-1-like. Pulsed-field gel electrophoresis showed 19 types and 25 of 74 isolates had an identical pattern, indicating nosocomial spread. Dissemination of ESBL- and PABL-producing K. pneumoniae strains in Korea is a particular concern, as it limits the choice of antimicrobial agents for treatment of infections.

Anti-Bacterial Agents↗
PubMed2000

[Occurrence of beta-lactamase type ESBL in rods of the Serratia species].

Serratia spp. has been identified as an important opportunistic pathogen agent in nosocomial infections. The aim of the study was the determination of extended spectrum beta-lactamases (ESBL) occurrence among 78 of Serratia spp. strains isolated in 1996-1998 from clinical specimens obtained from patients of State Clinical Hospital in Bydgoszcz. Identification of Serratia spp. strains was performed in automatic ATB system with ID 32GN strips (bioMérieux). The strains with ESBL activity were detected by double-disc method according to Jarlier et al. (10) with small modifications. Clavulanic acid, tazobactam and sulbactam were used as the inhibitors of ESBLs. Drug-susceptibility was determined by disc-diffusion method according to NCCLS standards. Forty-five (57.7%) of the strains were ESBL (+). All of them belonged to S. marcescens species. The majority--91.1% of strains was derived from urine, 3 from wound and 1 from blood. The obtained results indicate the necessity of monitoring of ESBL-producing strains among gram-negative rods from clinical specimen. The aims of such a procedure are to control and to prevent their dissemination within hospital, as well as to avoid therapeutic failures.

Blood↗
PubMed2001

[Occurrence of beta-lactamase type ESBL and IBL in Pseudomonas aeruginosa rods].

The aim of the study was to determine extended spectrum beta-lactamases (ESBL) and inducible beta-lactamases (IBL) among Pseudomonas aeruginosa strains. A total of 43 strains isolated from humans (6), hospital sink (1), fish (15), cattle (5), swine (5), dog (1), redder (1) fur animals (9) were studied. ESBL-producing strains were detected with double disc diffusion test according to Jarlier et al. (8). Clavulonate and tazobactam were used as the inhibitors of ESBL. Inducible beta-lactamases were determined using double disc method according to Sanders (15). Cefoxitin was the inductor of these beta-lactamases. The susceptibility study was carried out using the disc diffusion method according to NCCLS standards. A total of 8 ESBL (18.6% of all strains) and 31 (72%) IBL producing strains were detected. The obtained results indicate the necessity of monitoring of ESBL- and IBL-producing strains of Pseudomonas aeruginosa.

Animals↗
PubMed2006

[Prevalence of ESBL strains in urinary tract infections in children in 1996 and 2004].

Ethiological agents in urinary tract infections and prevalence of bacterial strains producing extended spectrum of beta-lactamases isolated from urine of children with urinary tract infections were compared. Patients were hospitalized in Department of Pediatry, Pediatric Gastroenterology and Oncology of Medical University of Gdańsk in 1996 and 2004. Seventy bacterial strains isolated from urine in 1996 and 113 strains isolated in 2004 were analyzed. In both years Enterobacteriaceae were the most frequently encountered with Escherichia coli predominance. Proteus spp. (10.9%), Enterobacter spp. (7.1%), Klebsiella spp. (4.4%), and Enterococcus spp. (9.3%) were isolated rarely. Among bacteria isolated in 1996 there were no ESBL strains while in 2004 ESBL strains accounted for 11.5% of all urinary bacteria. Klebsiella oxytoca (25%) and Klebsiella pneumaniae (20%) produced ESBL most frequently. ESBL production was less frequent in Escherichia coli (13.2%) and Proteus mirablilis (10%). In conclusion, among bacteria isolated from urine of children with urinary tract infections G(-) strains producing ESBL were encountered only in recent years.

Child↗
PubMed2005

Extended spectrum b lactamases (ESBL) in clinical isolates of Klebsiella pneumoniae and Escherichia coli.

The present study was conducted to find the prevalence of Extended spectrum b Lactamase (ESBL) producing strains of Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. Coli) in different clinical samples received at the Department of Microbiology, Medical College Baroda. A total of 187 clinical isolates (106 of K. pneumoniae and 81 of E. Coli) were tested for resistance to any one of the three Third generation cephalosporins (3GC) namely cefotaxime, ceftazidime and ceftriaxone. 100 isolates (57 of K. pneumoniae and 43 of E. Coli) were found to be resistant to at least one of the 3GC tested. These were then tested for ESBL production by Double Disc Diffusion Synergy Test (DDST) using Ceftriaxone, Ceftazidime, and Cefotaxime along with Augmentin as well as by the MIC reduction test. ESBL was detected in 53 isolates (33 K. pneumoniae and 20 E. coli). Using the interpretative guidelines of the NCCLS, 24% to 27% of the ESBL isolates would have been reported to be susceptible to the 3GC by routine antimicrobial susceptibility methods. DDST was found to be a useful, simple and cost effective test for the detection of ESBL producing strains.

Anti-Bacterial Agents↗
PubMed2006

Multidrug-resistant and extended-spectrum beta-lactamase (ESBL)-producing Salmonella enterica (serotypes Typhi and Paratyphi A) from blood isolates in Nepal: surveillance of resistance and a search for newer alternatives.

OBJECTIVES: We evaluated the prevalence of multidrug resistance (MDR) and production of extended spectrum beta-lactamase (ESBL) by Salmonella enterica (serotypes Typhi and Paratyphi A) in a teaching hospital in Nepal. The MDR strains of S. enterica were also tested for susceptibility to newer antibiotics. METHODS: Blood cultures were obtained from 4105 patients with febrile illnesses. Isolates of S. enterica were serotyped and antibiotic susceptibility testing was carried out using disk diffusion (Kirby-Bauer) and E-tests. ESBL screening and phenotype confirmation were done following National Committee for Clinical Laboratory Standards (NCCLS) recommendations for Escherichia coli. RESULTS: A total of 541 isolates of S. enterica serotypes Typhi (47%) and Paratyphi A (53%) were grown. Twenty-eight isolates (5%) of S. enterica were resistant to two or more antibiotics (MDR isolates), with a greater prevalence among serotype Paratyphi A (7%). All ESBL producers (three isolates) were serotype Paratyphi A. Most of the MDR S. enterica showed reduced susceptibility to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, ofloxacin, and ciprofloxacin, and had good susceptibility to extended-spectrum cephalosporins and carbapenems. Among the fluoroquinolones, gatifloxacin demonstrated better in vitro activity compared to levofloxacin, ciprofloxacin, and ofloxacin. CONCLUSIONS: A greater prevalence of S. enterica serotype Paratyphi A with higher rates of multidrug resistance and ESBL production is concerning for natives as well as travelers in Nepal since the current typhoid vaccines do not provide protection against this serotype.

Anti-Bacterial Agents↗
PubMed2000

Recommendation for treatment of severe infections caused by Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs).

Extended-spectrum beta-lactamase (ESBL)-producing organisms are a global problem. No randomized controlled trials have ever been performed to guide optimal treatment. However, in vitro studies and observational studies strongly suggest that carbapenems (imipenem or meropenem) should be regarded as drugs of choice for serious infections due to ESBL-producing organisms. Other beta-lactam antibiotics (cefepime, beta-lactam/beta-lactamase inhibitor combinations) are not suitable as first-line therapy. The increasing frequency of the association between quinolone resistance and ESBL production have greatly limited the role of this class of antibiotic against ESBL producers.

Anti-Bacterial Agents↗
PubMed2005

Emergence of Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs) in the community.

Enterobacteriaceae, especially Klebsiella spp. producing extended-spectrum beta-lactamases (ESBLs) such as SHV and TEM types, have been established since the 1980s as a major cause of hospital-acquired infections. Appropriate infection control practices have largely prevented the dissemination of these bacteria within many hospitals, although outbreaks have been reported. However, during the late 1990s and 2000s, Enterobacteriaceae (mostly Escherichia coli) producing novel ESBLs, the CTX-M enzymes, have been identified predominantly from the community as a cause of urinary tract infections. Resistance to other classes of antibiotics, especially the fluoroquinolones, is often associated with ESBL-producing organisms. Many clinical laboratories are still not aware of the importance of screening for ESBL-producing Enterobacteriaceae originating from the community. A heightened awareness of these organisms by clinicians and enhanced testing by laboratories, including molecular surveillance studies, is required to reduce treatment failures, to limit their introduction into hospitals and to prevent the spread of these emerging pathogens within the community.

Community-Acquired Infections↗
PubMed2006

Activity of human beta-defensins 2 and 3 against ESBL-producing Klebsiella strains.

OBJECTIVES: To test the bactericidal activity of human beta-defensins (hBDs) 2 and 3 against extended-spectrum beta-lactamase (ESBL)-producing Klebsiella strains. METHODS: Thirty-six Klebsiella pneumoniae and seventeen Klebsiella oxytoca ESBL-producing isolates from nosocomial infections were tested. The bactericidal activity of recombinantly synthesized hBD-2 and -3 was tested and the results were given either as lethal doses killing > or = 90% of bacteria (LD90s) or as MBCs (> or = 99.9% killing). RESULTS: Except for one intermediately susceptible strain (MBC = 25 mg/L), all other ESBL-producing strains were highly susceptible to both defensins (LD90s and MBCs < or = 12.5 mg/L). CONCLUSIONS: The results underline the high efficacy of hBD-2 and -3 against ESBL-producing Klebsiella, making both defensins attractive candidates as antimicrobial agents to combat these increasingly troublesome bacteria.

Anti-Bacterial Agents↗
PubMed2002

Evaluation of the Etest ESBL and the BD Phoenix, VITEK 1, and VITEK 2 automated instruments for detection of extended-spectrum beta-lactamases in multiresistant Escherichia coli and Klebsiella spp.

Seventy-four isolates of multiresistant Escherichia coli and Klebsiella spp. recovered during a 3-year period and 17 control strains with genotypically identified beta-lactamases were tested for the production of extended-spectrum beta-lactamases (ESBLs) by using the Etest and the VITEK 1, VITEK 2, and Phoenix automated instruments. The use of the Etest was evaluated by investigating its accuracy in detecting the ESBLs of the control strains and by comparing interpretation results of laboratory technicians and experts. The accuracy of the Etest was 94%. With the Etest as the reference for the clinical strains and the genotype as the reference for the control strains, the automated instruments detected the ESBLs with accuracies of 78% (VITEK 2), 83% (VITEK 1), and 89% (Phoenix). No significant difference between the systems with regard to the control strains was detected. The VITEK 2 did, however, perform less well than the Phoenix (P = 0.03) on the collection of clinical isolates, mainly because of its high percentage of indeterminate test results (11%). No significant difference between the performances of the VITEK 1 and either the VITEK 2 or the Phoenix was found. However, because of its associated BDXpert system the Phoenix showed the best performance. The Etest was found to be an accurate test but was limited by its indeterminate results (4%), its inability to differentiate between K1 hyperproduction and ESBLs, questionable guidelines concerning mutants inside the inhibition zones, and the inability of the technicians to recognize subtle zone deformations.

Anti-Bacterial Agents↗
PubMed2006

[High relationship between ciprofloxacin use and prevalence of ESBL Klebsiella pneumoniae].

BACKGROUND: To assess the relationship between ciprofloxacin use and the prevalence of extended spectrum betalactamases (ESBL) Klebsiella pneumoniae. PATIENTS AND METHODS: Semestral mean values regarding use of antibiotic and prevalence of ESBL Kp were compared during 9 semesters using linear regression and coefficient of correlation. RESULTS: The only statistically significant correlation was ciprofloxacin use and ESBL(+) K. pneumoniae prevalence, with a coefficient of correlation of 0.86 and p = 0.0027 using linear regression. CONCLUSIONS: Ciprofloxacin use must be taking into account when considering infection control programs due to high prevalence rates of ESBL(+) K. pneumoniae in the hospital setting.

Anti-Bacterial Agents↗
PubMed2001

[Clinical characteristics of emerging multiple-drug-resistant gram-negative rods producing extended-spectrum beta-lactamases (ESBLs)].

The prevalence of organisms producing extended-spectrum beta-lactamases(ESBLs) has been increasing all over the world. ESBLs confer resistance to cefotaxime, ceftazidime, aztreonam, extended-spectrum penicillins, and structurally related beta-lactams in clinical isolates of K. pneumoniae and E. coli. Under the influence of antimicrobial agents, bacteria that primarily produce TEM-type or SHV-type beta-lactamases developed point mutations in structural genes which served to extend the substrate specificity of the enzymes. Infections caused by ESBLs producing isolates are difficult to detect with current susceptibility tests, and are difficult to treat. This article provides an historical overview of the emergence of ESBLs carrying gram-negative rods and consider how to treat their infections.

Drug Resistance, Multiple↗
PubMed2002

[Use of new methods for detection of beta-lactamases with extended-spectrum substrates (ESBLs)].

The aim of performed examinations was to compare results of two methods applied for the detection of extended-spectrum beta-lactamases (ESBLs). Two hundred and sixty strains of Gram-negative rods were cultured from clinical specimens obtained from hospitalized patients. These strains were identified as ESBL-positive on the basis of the double-disc method (DDST) according to Jarlier et al. (1988) results. Identification of strains was performed in automatic ATB Expression system (bioMerieux, France). All strains were determined using a novel test for detection of ESBL-type enzymes (DD) according to Appleton (1999). Two discs are applied in this test: with cefpodoxime (CPD) and with cefpodoxime/clavulanate (CD 01, diagnostic disc). Consistent results of two methods (DDST and DD) were obtained in the case of 166 from among 260 of examined strains (60.4%). Consistent results concerned 161 out of 222 examined strains of enteric rods (72.5%) and only 5 from among 38 of other strains (mostly belonging to the group of non-fermenting rods). On the basis of performed investigations it can be stated that the novel method of extended-spectrum beta-lactamases (ESBLs) detection (DD) according to Appleton (1999) is more objective and easier for interpretation than the double-disc synergy test (DDST) according to Jarlier et al. (DDST), which is widely applied in the routine microbiological diagnostics.

Bacterial Typing Techniques↗
PubMed2004

[Comparison of the results of disc diffusion methods applied for detection of ESBL-positive strains of gram-negative rods].

Examinations were undertaken to compare the results of disc diffusion tests applied for detection of strains producing extended-spectrum beta-lactamases (ESBLs). A total of 120 clinical strains were used in experiments. These strains were determined as ESBL-positive on the basis of consistent results of two methods: the double disc synergy test (DDST) according to Jarlier et al. (1988) and the diagnostic disc test (DD, version CPD/CD 01) according to Appleton (1999). In the next step examined strains were analysed in two further tests, which are variants of DD method: CAZ/CD 02 test with discs containing ceftazidime and ceftazidime/clavulanic acid, and CTX/CD 03 test with the use of cefotaxime and cefotaxime/clavulanic acid discs. ESBL-positive strains first of all belonged to the species E. coli and K. pneumoniae. In the case of seven analysed strains consistent results of determinations were not obtained with the use of different disc diffusion methods. Application of several disc diffusion methods to determine ESBL-positive strains of gram-negative rods increases the probability of their proper identification.

Bacterial Typing Techniques↗
PubMed2004

[ESBL-positive strains of the Bacteroides fragilis group isolated from patients at the regional hospital center in Płock (Poland)].

The aim of this study was to confirm a presumptive qualification of clinical B. fragilis group strains isolated in Płock as ESBL-positive strains and to determine some properties of these strains. Twenty four clinical strains belonging to the B. fragilis group, isolated first of all from surgical patients, were received for testing. Identification of strains was performed in the automatic ATB Expression system (bioMerieux sa, France) using biochemical API 20 A strips. Strains were tested for the production of catalase (ID Color Catalase test, bioMerieux sa) and beta-lactamase (Cefinase, BBL, Becton Dickinson, USA). Susceptibility of strains to four antimicrobial agents: clindamycin, metronidazole, amoxicillin/clavulanic acid and imipenem was determined by Etest (AB Biodisk, Sweden). ESBLs were detected with the use of two disc diffusion methods: the double-disc synergy test (DDST) according to Jarlier et al. and the diagnostic disc (DD) test according to Appleton. Seventeen of examined strains belonged to the species Bacteroides fragilis, three--to B. ovatus/thetaiotaomicron, two--to B. distasonis, one--to B. uniformis and one--to B. stercoris/eggerthii. One strain (B. uniformis) did not produce catalase, whereas all strains produced beta-lactamases. Examined strains were susceptible in vitro to metronidazole, amoxicillin/clavulanic acid and imipenem. One clindamycin-resistant strain was detected (B. fragilis). Occurrence of ESBL-type enzymes was confirmed in 22 strains of following species: B. fragilis (17 strains), B. ovatus/thetaiotaomicron (3), B. distasonis (1) and B. uniformis (1). Clinical strains of the B. fragilis group with a new mechanism of resistance to beta-lactam antibiotics appeared during last years in Poland. They produce extended-spectrum beta-lactamases (ESBLs), so they are resistant to penicillins, cephalosporins and monobactams. Monitoring of infections caused by these threatening strains in hospital patients is very important.

Amoxicillin-Potassium Clavulanate Combination↗