Plasmidic Extended-Spectrum β-Lactamases in
            <i>Vibrio cholerae</i>
            O1 El Tor Isolates in Argentina

Petroni, Alejandro; Corso, Alejandra; Melano, Roberto G.; Cacace, María Luisa; Bru, Ana María; Rossi, Alicia; Galas, Marcelo

doi:10.1128/aac.46.5.1462-1468.2002

Cited by 76 publications

(57 citation statements)

References 41 publications

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“…They have now been detected in every populated continent (9,22,23,49,58,70,71,81,90,120,140,190,226,253,284,288,305,333,353,414,428,437). For some years, CTX-M ESBLs were predominantly found in three geographic areas: South America, the Far East, and Eastern Europe.…”

Section: Ctx-m and Toho ␤-Lactamasesmentioning

confidence: 99%

Extended-Spectrum β-Lactamases: a Clinical Update

2005

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SUMMARY Extended-spectrum β-lactamases (ESBLs) are a rapidly evolving group of β-lactamases which share the ability to hydrolyze third-generation cephalosporins and aztreonam yet are inhibited by clavulanic acid. Typically, they derive from genes for TEM-1, TEM-2, or SHV-1 by mutations that alter the amino acid configuration around the active site of these β-lactamases. This extends the spectrum of β-lactam antibiotics susceptible to hydrolysis by these enzymes. An increasing number of ESBLs not of TEM or SHV lineage have recently been described. The presence of ESBLs carries tremendous clinical significance. The ESBLs are frequently plasmid encoded. Plasmids responsible for ESBL production frequently carry genes encoding resistance to other drug classes (for example, aminoglycosides). Therefore, antibiotic options in the treatment of ESBL-producing organisms are extremely limited. Carbapenems are the treatment of choice for serious infections due to ESBL-producing organisms, yet carbapenem-resistant isolates have recently been reported. ESBL-producing organisms may appear susceptible to some extended-spectrum cephalosporins. However, treatment with such antibiotics has been associated with high failure rates. There is substantial debate as to the optimal method to prevent this occurrence. It has been proposed that cephalosporin breakpoints for the Enterobacteriaceae should be altered so that the need for ESBL detection would be obviated. At present, however, organizations such as the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards) provide guidelines for the detection of ESBLs in klebsiellae and Escherichia coli. In common to all ESBL detection methods is the general principle that the activity of extended-spectrum cephalosporins against ESBL-producing organisms will be enhanced by the presence of clavulanic acid. ESBLs represent an impressive example of the ability of gram-negative bacteria to develop new antibiotic resistance mechanisms in the face of the introduction of new antimicrobial agents.

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Section: Ctx-m and Toho ␤-Lactamasesmentioning

confidence: 99%

Extended-Spectrum β-Lactamases: a Clinical Update

2005

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“…Detection of bla CTX-M genes was performed in the following sequence: isolates were first amplified with the primers CTX-MA and CTX-MB, which correspond to conserved areas of bla CTX-M -type genes and result in a 550-bp product (1); isolates containing genes encoding CTX-M-type ␤-lactamases were evaluated further with three sets of oligonucleotides that can distinguish several of the major groups within the bla CTX-M -type gene family and do not amplify the closely related bla K-1 gene of K. oxytoca. The primer set CTX-M-9 (Up/4)-CTX-M-9 (Dn/860) was used to amplify bla CTX-M-9 and related genes (22); the primer set CTX-M-2F-CTX-M-2R, based on the report by Petroni et al (19), was used to amplify bla CTX-M-2 and related genes; and primer set CTX-M-F3-CTX-M-R3 (6) was used to amplify bla CTX-M-10 and related genes. Control organisms included strains of E. coli or Salmonella that possessed either bla TEM-1 , bla SHV-3 , bla OXA-3 , bla OXA-4 , bla , bla CTX-M-5 , bla CTX-M-9 , or the bla CTX-M-10 gene.…”

Section: Methodsmentioning

confidence: 99%

Utility of NCCLS Guidelines for Identifying Extended-Spectrum β-Lactamases in Non- Escherichia coli and Non- Klebsiella spp. of Enterobacteriaceae

et al. 2004

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NCCLS screening and confirmation methods for detecting extended-spectrum ␤-lactamases (ESBLs) apply only to Escherichia coli and Klebsiella spp., yet ESBLs have been found in other members of the family Enterobacteriaceae. We evaluated the effectiveness of NCCLS methods for detecting ESBLs in 690 gramnegative isolates of Enterobacteriaceae that excluded E. coli, Klebsiella pneumoniae, and Klebsiella oxytoca. Isolates were collected between January 1996 and June 1999 from 53 U.S. hospitals participating in Project ICARE (Intensive Care Antimicrobial Resistance Epidemiology). The antimicrobial susceptibility patterns of the isolates were determined by using the NCCLS broth microdilution method (BMD), and those isolates for which the MIC of ceftazidime, cefotaxime, ceftriaxone, or aztreonam was >2 g/ml or the MIC of cefpodoxime was >8 g/ml (positive ESBL screen test) were further tested for a clavulanic acid (CA) effect by BMD and the disk diffusion method (confirmation tests). Although 355 (51.4%) of the isolates were ESBL screen test positive, only 15 (2.2%) showed a CA effect. Since 3 of the 15 isolates were already highly resistant to the five NCCLS indicator drugs, ESBL detection would have an impact on the reporting of only 1.7% of the isolates in the study. Only 6 of the 15 isolates that showed a CA effect contained a bla TEM , bla SHV , bla CTX-M , or bla OXA ␤-lactamase gene as determined by PCR (with a corresponding isoelectric focusing pattern). Extension of the NCCLS guidelines for ESBL detection to Enterobacteriaceae other than E. coli and Klebsiella spp. does not appear to be warranted in the United States at present, since the test has poor specificity for this population and would result in changes in categorical interpretations for only 1.7% of Enterobacteriaceae tested.First described in 1983 (10), extended-spectrum ␤-lactamases (ESBLs) have contributed to the dramatic increase in resistance to ␤-lactam agents among gram-negative bacteria in recent years (2,3,8). These enzymes, encoded by genes that are typically plasmid borne, hydrolyze penicillins, cephalosporins, and aztreonam and are inhibited by clavulanic acid (CA) (2, 3, 5). Although most commonly produced by Escherichia coli and Klebsiella spp., ESBLs may be harbored by many other gram-negative bacilli as well, including but not limited to many other bacteria in the family Enterobacteriaceae (7,8,25).While most of the currently known ESBLs are derived from the older ␤-lactamases TEM-1, TEM-2, and SHV-1 (2, 11, 25), CTX-M enzymes are also inhibited by CA and are in the category of ESBLs. In addition, some of the enzymes of the OXA family, although belonging to functional group 2d (5), show a CA effect and are considered ESBLs (2).While a variety of phenotypic and molecular methods have been successfully employed to confirm the presence of ESBLs in clinical isolates, their use is too labor-intensive to be practical for routine screening in microbiology laboratories. Since routine susceptibility testing does not always detect the presence of ...

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“…Strains producing other CTX-M enzymes have been isolated in separate geographic areas, including Europe (9,15,16,35,40), South America (4,7,30), and the Middle and Far East (4,18,23,41). CTX-M-type ␤-lactamases can be classified into four clusters according to In this paper, we report a nosocomial outbreak of infections caused by CTX-M-2 ␤-lactamase-producing Proteus mirabilis in a urology ward.…”

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confidence: 99%

Nosocomial Outbreak of Infections by Proteus mirabilis That Produces Extended-Spectrum CTX-M-2 Type β-Lactamase

et al. 2003

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Nineteen multidrug-resistant Proteus mirabilis strains were isolated from 19 patients suffering from infections probably caused by P. mirabilis. These strains were recovered from urine or other urogenital specimens of 16 inpatients and three outpatients with a hospitalization history in a urology ward of Funabashi Medical Center, from July 2001 to August 2002. These strains demonstrated resistance to cefotaxime, ceftriaxone, cefpodoxime, and aztreonam, while they were highly susceptible to ceftazidime (MIC, <0.5 g/ml). The resistance level of these strains to cefotaxime was decreased by the presence of clavulanic acid. Therefore, the strains were speculated to produce extended-spectrum class A ␤-lactamases. These strains were later found to carry bla CTX-M-2 genes by both PCR and sequencing analyses. The profiles of SmaI-digested genomic DNA of 19 isolates were distinguished into five different clusters by biased sinusoidal field gel electrophoresis. Four of them, consisting of 18 isolates, were suggested to be a clonal expansion. These findings suggested that a nosocomial outbreak of infections by CTX-M-2-producing P. mirabilis had occurred in our medical center. Most patients suffered from urogenital malignancies with long-term catheterization. Cefazolin, cefoperazonesulbactam, and/or levofloxacin were mostly administered to the patients, but these agents seemed ineffective for eradication of CTX-M-2 producers. Early recognition and rapid identification of colonizing antimicrobialresistant bacteria, including CTX-M-2-producing P. mirabilis, would be the most effective measures to cope with further spread of this kind of hazardous microorganism in clinical environments.The increasing prevalence of plasmid-mediated extendedspectrum ␤-lactamases (ESBLs) in members of the family Enterobacteriaceae has become a serious clinical problem on a worldwide scale (8). ESBLs of Ambler's molecular class A (1) belonging to Bush's functional group 2be (10) are capable of hydrolyzing a wide range of ␤-lactams, including oxyimino-␤-lactams and monobactam, but usually remain ineffective against cephamycins such as cefoxitin, cefmetazole, and cefotetan as well as carbapenems. These class A ␤-lactamases tend to be blocked by ␤-lactamase inhibitors such as clavulanic acid (10). The majority of ESBLs are derivatives of TEM-1, TEM-2, or SHV-1 enzymes, resulting from a few amino acid substitutions (10). In contrast to these TEM-and SHV-derived ESBLs, CTX-M type ␤-lactamases, which constitute a new family of class A enzymes, are exclusively active against cefotaxime compared to other oxyimino-cephalosporins, including ceftazidime (39).More than 30 CTX-M-type ␤-lactamases have so far been described in various species of Enterobacteriaceae but mostly in Salmonella enterica serovar Typhimurium, Escherichia coli, and Klebsiella pneumoniae since the initial reports of Toho-1-producing E. coli in Japan (18) and CTX-M-1/MEN-1 in 1989 in Germany and France (2, 3). Strains producing other CTX-M enzymes have been isolated in separate geographic ...

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Plasmidic Extended-Spectrum β-Lactamases in Vibrio cholerae O1 El Tor Isolates in Argentina

Cited by 76 publications

References 41 publications

Extended-Spectrum β-Lactamases: a Clinical Update

Extended-Spectrum β-Lactamases: a Clinical Update

Utility of NCCLS Guidelines for Identifying Extended-Spectrum β-Lactamases in Non- Escherichia coli and Non- Klebsiella spp. of Enterobacteriaceae

Nosocomial Outbreak of Infections by Proteus mirabilis That Produces Extended-Spectrum CTX-M-2 Type β-Lactamase

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