What’s new in β-lactamases?

Bradford, Patricia A.

doi:10.1007/s11908-001-0054-z

Cited by 20 publications

(14 citation statements)

References 72 publications

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“…However, the emergence of antimicrobial resistance has posed a worldwide challenge to public health by hampering effective chemotherapy [2,3]. The use of antimicrobials in both human and veterinary medicine has led to the selection of resistant organisms, resulting in dissemination of drug-resistant bacteria in hospitals and the community [4,5].…”

Section: Introductionmentioning

confidence: 99%

Prevalence and multidrug resistance of Escherichia coli from community-acquired infections in Lagos, Nigeria

Adenipekun

Jackson

Ramadan

et al. 2016

J Infect Dev Ctries

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Introduction: The emergence of multidrug resistance (MDR; resistance to ≥ 2 more antimicrobials) in Escherichia coli is of concern due to complications encountered in treatment. Methodology: In this study, prevalence, antimicrobial resistance, and genetic characteristics of MDR community isolates of E. coli from Lagos, Nigeria were determined. Urine and stool samples were obtained from outpatients attending Lagos State hospitals and from animal handlers in abattoirs, poultries, and open markets, from December 2012 to July 2013.Results: Approximately 50% of urine (200/394) and 88% of stool samples (120/136) were positive for E. coli. Based upon β-lactamase production, a subset of those isolates was selected for further study. Of the 22 antimicrobials tested, E. coli exhibited resistance to all antimicrobials except amikacin and piperacillin/tazobactam. The highest levels of resistance were to tetracycline (182/247; 73.7%), trimethoprim/sulfamethoxazole (152/247; 61.5%), and ampicillin (147/247; 59.1%). Resistance to the cephalosporins ranged from 1.6%-15% including the third-and fourth-generation cephalosporins, cefpodoxime (20/247; 8.1%) and cefepime (4/247; 1.6%), respectively. MDR was observed in 69.6% (172/247) of the isolates. Forty-eight E. coli resistant to at least five antimicrobials were selected for further analysis using pulsed-field gel electrophoresis; seven distinct clusters were observed among the diverse patterns. Of the 48 MDR E. coli, 30 different sequence types (ST) were detected using multilocus sequence typing, including four ST131. Conclusions: This study demonstrated circulating MDR E. coli in the Nigerian community. Monitoring of antimicrobial resistance in developing countries is necessary to optimize empiric treatment and the prudent use of antimicrobials.

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Section: Introductionmentioning

confidence: 99%

Prevalence and multidrug resistance of Escherichia coli from community-acquired infections in Lagos, Nigeria

Adenipekun

Jackson

Ramadan

et al. 2016

J Infect Dev Ctries

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“…As ␤-lactam antibiotics stable against ␤-lactamases have been developed and used clinically, extended-spectrum ␤-lactamases (ESBLs) have increased in prevalence, especially since the beginning of the 1990s (2). These enzymes cause the serious clinical problem of resistance to broad-spectrum cephalosporins such as cefotaxime, ceftazidime, or ceftriaxione.…”

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confidence: 99%

Role of a Mutation at Position 167 of CTX-M-19 in Ceftazidime Hydrolysis

Kimura

Ishiguro

Ishii

et al. 2004

Antimicrob Agents Chemother

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CTX-M-19 is a recently identified ceftazidime-hydrolyzing extended-spectrum ␤-lactamase, which differs from the majority of CTX-M-type ␤-lactamases that preferentially hydrolyze cefotaxime but not ceftazidime. To elucidate the mechanism of ceftazidime hydrolysis by CTX-M-19, the ␤-lactam MICs of a CTX-M-19 producer, and the kinetic parameters of the enzyme were confirmed. We reconfirmed here that CTX-M-19 is also stable at a high enzyme concentration in the presence of bovine serum albumin (20 g/ml Comparison of the MICs with the catalytic efficiency (k cat /K m ) of these enzymes showed that some ␤-lactams, including cefotaxime, ceftazidime, and aztreonam showed a similar correlation. Using the previously reported crystal structure of the Toho-1 ␤-lactamase, which belongs to the CTX-M-type ␤-lactamase group, we have suggested characteristic interactions between the enzymes and the ␤-lactams ceftazidime, cefotaxime, and aztreonam by molecular modeling. Aminothiazole-bearing ␤-lactams require a displacement of the aminothiazole moiety due to a severe steric interaction with the hydroxyl group of Ser167 in CTX-M-19, and the displacement affects the interaction between Ser130 and the acidic group such as carboxylate and sulfonate of ␤-lactams.

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“…ESBLs are typically plasmid-mediated, clavulanate-susceptible enzymes that hydrolyze penicillins, cephalosporins, and aztreonam. They have been detected worldwide in gram-negative pathogens, principally members of the family Enterobacteriaceae (5,15,24,25,33,37). Plasmidmediated AmpC ␤-lactamases are derivatives of the chromosomally encoded, clavulanate-resistant AmpC cephalosporinases of Enterobacter cloacae, Citrobacter freundii, Morganella morganii, Hafnia alvei, and other yet-to-be-determined gramnegative bacilli.…”

mentioning

confidence: 99%

“…Plasmidmediated AmpC ␤-lactamases are derivatives of the chromosomally encoded, clavulanate-resistant AmpC cephalosporinases of Enterobacter cloacae, Citrobacter freundii, Morganella morganii, Hafnia alvei, and other yet-to-be-determined gramnegative bacilli. Like ESBLs, these enzymes have been detected worldwide (3)(4)(5)23). Genes encoding both ESBLs and plasmid-mediated AmpC ␤-lactamases are usually located on large multidrug resistance plasmids.…”

mentioning

confidence: 99%

Occurrence of Newer β-Lactamases in Klebsiella pneumoniae Isolates from 24 U.S. Hospitals

Moland

Black

Ourada

et al. 2002

Antimicrob Agents Chemother

109

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Despite the discovery of novel ␤-lactamases such as extended-spectrum ␤-lactamases (ESBLs), imported AmpC, and carbapenem-hydrolyzing ␤-lactamases at least a decade ago, there remains a low level of awareness of their importance and how to detect them. There is a need to increase the levels of awareness of clinical laboratories about the detection of newer ␤-lactamases. Therefore, a study was conducted in 2000 to investigate the occurrence of these ␤-lactamases in Klebsiella pneumoniae isolates at 24 U.S. medical centers. To enhance the likelihood of detecting imported AmpC and carbapenem-hydrolyzing ␤-lactamases, participating laboratories were permitted to include archived strains (1996 to 2000) that were intermediate or resistant to either cefoxitin or imipenem. The ␤-lactamase production of 408 isolates positive by screening of 1,123 isolates was investigated by ESBL phenotypic confirmation tests; and for AmpC and carbapenem-hydrolyzing ␤-lactamases, three-dimensional tests, isoelectric focusing, ␤-lactamase inhibitor studies, spectrophotometric assays, induction assays, and molecular tests were used. ESBL-producing isolates were detected at 18 of the 24 sites (75%), imported AmpC-producing isolates were detected at 10 sites (42%), inducible imported AmpC-producing isolates were detected at 3 sites (12.5%), and a molecular class A carbapenem-hydrolyzing enzyme was detected at 1 site (4%). No class B or D carbapenem-hydrolyzing enzymes were detected. ESBLs and imported AmpC ␤-lactamases were detected at a significant number of sites, indicating widespread penetration of these enzymes into U.S. medical institutions. Because these enzymes may significantly affect therapeutic outcomes, it is vital that clinical laboratories be aware of them and be able to detect their occurrence.

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What’s new in β-lactamases?

Cited by 20 publications

References 72 publications

Prevalence and multidrug resistance of Escherichia coli from community-acquired infections in Lagos, Nigeria

Prevalence and multidrug resistance of Escherichia coli from community-acquired infections in Lagos, Nigeria

Role of a Mutation at Position 167 of CTX-M-19 in Ceftazidime Hydrolysis

Occurrence of Newer β-Lactamases in Klebsiella pneumoniae Isolates from 24 U.S. Hospitals

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