Molecular characterization of imipenem-resistant, cfiA-positive Bacteroides fragilis isolates from the USA, Hungary and Kuwait

Sóki, Jozsef; Fodor, Eleonóra; Hecht, David W.; Edwards, Richard; Rotimi, Vincent O.; Kerekes, Irén; Urbán, Edit; Nagy, Elisabeth

doi:10.1099/jmm.0.05452-0

Cited by 82 publications

(61 citation statements)

References 34 publications

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“…d Forty-nine/82 (moxifloxacin) and 118/122 (clindamycin) isolate MICs were Ͼ16 g/ml; concentrations of moxifloxacin and clindamycin of Ͼ16 g/ml were not tested. (9,18). In the current study, only 55.6% of all B. fragilis group isolates tested were susceptible to moxifloxacin; susceptibilities to moxifloxacin were highest for P. distasonis/P.…”

Section: Discussionmentioning

confidence: 99%

Prevalence of Antimicrobial Resistance among Clinical Isolates of Bacteroides fragilis Group in Canada in 2010-2011: CANWARD Surveillance Study

Karlowsky

Walkty

Adam

et al. 2012

Antimicrob Agents Chemother

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Section: Discussionmentioning

confidence: 99%

Prevalence of Antimicrobial Resistance among Clinical Isolates of Bacteroides fragilis Group in Canada in 2010-2011: CANWARD Surveillance Study

Karlowsky

Walkty

Adam

et al. 2012

Antimicrob Agents Chemother

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“…An evaluation of the molecular characterization of 15 strains of imipenem-resistant, cfiA-positive B. fragilis strains (109) noted that the cfiA genes of 10 of the strains were upregulated by insertion sequence (IS) elements, while 5 others did not harbor an IS but produced carbapenemase. These findings suggest that some isolates possessed novel inactivation mechanisms, suggesting that more than one mechanism of inactivation exists.…”

Section: ␤-Lactam Antibioticsmentioning

confidence: 99%

“…Carbapenem resistance occurs in Ͻ1% of U.S. isolates, and up to 3% of Bacteroides strains harbor one of the genes that is expressed at a very low level. BLA inhibitors cannot inactivate the carbapenemases, which are zinc metalloenzymes encoded by either ccrA or cfiA genes of the B. fragilis group (109).…”

Section: ␤-Lactam Antibioticsmentioning

confidence: 99%

Antianaerobic Antimicrobials: Spectrum and Susceptibility Testing

2013

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SUMMARY Susceptibility testing of anaerobic bacteria recovered from selected cases can influence the choice of antimicrobial therapy. The Clinical and Laboratory Standards Institute (CLSI) has standardized many laboratory procedures, including anaerobic susceptibility testing (AST), and has published documents for AST. The standardization of testing methods by the CLSI allows comparisons of resistance trends among various laboratories. Susceptibility testing should be performed on organisms recovered from sterile body sites, those that are isolated in pure culture, or those that are clinically important and have variable or unique susceptibility patterns. Organisms that should be considered for individual isolate testing include highly virulent pathogens for which susceptibility cannot be predicted, such as Bacteroides , Prevotella , Fusobacterium , and Clostridium spp.; Bilophila wadsworthia ; and Sutterella wadsworthensis . This review describes the current methods for AST in research and reference laboratories. These methods include the use of agar dilution, broth microdilution, Etest, and the spiral gradient endpoint system. The antimicrobials potentially effective against anaerobic bacteria include beta-lactams, combinations of beta-lactams and beta-lactamase inhibitors, metronidazole, chloramphenicol, clindamycin, macrolides, tetracyclines, and fluoroquinolones. The spectrum of efficacy, antimicrobial resistance mechanisms, and resistance patterns against these agents are described.

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“…PCR analysis was performed to detect the presence of the cfiA gene. The annealing temperature of the cfiA gene detection method described by Sóki et al (16) was increased to 62°C to avoid aspecific reactions. In cfiA-positive strains, the cfiA promoter region was amplified.…”

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confidence: 99%

Differentiation of cfiA -Negative and cfiA -Positive Bacteroides fragilis Isolates by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

et al. 2011

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Carbapenem resistance in Bacteroides fragilis is associated with cfiA-encoded class B metallo-beta-lactamase. cfiA-negative and cfiA-positive isolates belong to genotypically distinct groups. Of a total of 248 B. fragilis isolates included in this study, 214 were susceptible, 10 were intermediate, and 24 were resistant to meropenem. We show that matrix-assisted laser desorption ionization-time of flight mass spectrometry is able to differentiate between cfiA-negative and cfiA-positive isolates and predict carbapenem resistance in a routine laboratory setting.Bacteroides fragilis is a strictly anaerobic Gram-negative bacillus present in the human gut. It is recovered from various infection sites and frequently associated with abscess formation and sepsis. Carbapenem resistance in B. fragilis is emerging and associated with cfiA-encoded class B metallo-betalactamase, which is activated by insertion sequence (IS) elements. However, elevated MICs or resistance was also observed in strains that did not have activating IS elements in the upstream region of cfiA (17). In the 2003-2005 Belgian multicenter survey (18), the prevalence of the cfiA resistance gene was 7.4% (10/135) (19), which is high compared with the prevalence of cfiA positivity (2 to 7%) in other countries (5,6,13,15,20). In the survey, 4% (6/135) of B. fragilis isolates were intermediate or resistant to meropenem according to CLSI breakpoints (18).By using various molecular typing methods, such as arbitrarily primed PCR, ribotyping, multilocus enzyme electrophoresis, and sequencing of recA and glnA genes, cfiA-negative and cfiA-positive strains were shown to belong to two genotypically distinct groups (9, 10, 13). Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has the capacity to discriminate closely related species based on the spectrum of constantly expressed highly abundant proteins, such as ribosomal proteins. This technique was recently introduced as a rapid and accurate method for the identification of bacteria (2,7,14) and can also be applied in the identification of Bacteroides isolates (12). The aim of the present study was to examine the discriminatory power of MALDI-TOF MS to differentiate cfiA-positive from cfiA-negative B. fragilis strains in order to predict carbapenem susceptibility.The 135 B. fragilis clinical isolates from the survey mentioned above (18, 19), originating from nine Belgian hospitals, as well as 113 B. fragilis isolates from routine cultures collected at our laboratory since 2005 were analyzed. Identification was performed by appropriate biochemical and enzymatic tests (11) and confirmed by MALDI-TOF MS. Meropenem susceptibility was determined by Etest methodology (bioMérieux, Marcy l'Etoile, France). The CLSI breakpoints for susceptible and resistant strains are Յ4 mg/liter and Ն16 mg/liter, respectively (4). PCR analysis was performed to detect the presence of the cfiA gene. The annealing temperature of the cfiA gene detection method described by Sóki et al. (16) was increa...

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Molecular characterization of imipenem-resistant, cfiA-positive Bacteroides fragilis isolates from the USA, Hungary and Kuwait

Cited by 82 publications

References 34 publications

Prevalence of Antimicrobial Resistance among Clinical Isolates of Bacteroides fragilis Group in Canada in 2010-2011: CANWARD Surveillance Study

Prevalence of Antimicrobial Resistance among Clinical Isolates of Bacteroides fragilis Group in Canada in 2010-2011: CANWARD Surveillance Study

Antianaerobic Antimicrobials: Spectrum and Susceptibility Testing

Differentiation of cfiA -Negative and cfiA -Positive Bacteroides fragilis Isolates by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

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