Phenotypic Identifcation and Genotypic Characterization ofPlasmid-Mediated AmpC β-Lactamase-Producing Escherichia coli andKlebsiella pneumoniae Isolates in Iran

  • سال انتشار: 1401
  • محل انتشار: بیست و سومین کنگره بین المللی میکروب شناسی ایران
  • کد COI اختصاصی: MEDISM23_114
  • زبان مقاله: انگلیسی
  • تعداد مشاهده: 150
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نویسندگان

Saeedeh Robatjazi

Medical Microbiology Research Center, Qazvin University of Medical Science, Qazvin, Iran

Farhad Nikkhahi

Medical Microbiology Research Center, Qazvin University of Medical Science, Qazvin, Iran

چکیده

Background and Aim : One of the mechanisms of Klebsiella pneumoniae and Escherichia coliresistance to β-lactam antibiotics is the production of β-lactamase enzymes. Among these are theAmpC β-lactamases, which confer resistance to a class of antibiotics. However, little is knownabout the AmpC β-lactamases of K. pneumoniae and E. coli clinical isolates in Qazvin, Iran. Thisstudy was designed to assess the AmpC β-lactamases-producing strains and also identify theprevalence of AmpC β-lactamases genes.Methods : Antimicrobial susceptibility tests were performed on ۴۳۵ K. pneumoniae and E. coliisolates using disk difusion technique. Plasmid-mediated AmpC genes were studied using amultiplex PCR assay. The AmpC β-lactamase-producer isolates were studied by employingcefoxitin disk difusion test, AmpC induction test, AmpC cefoxitin-EDTA test, and boronic aciddisk test.Results : Our results showed that of ۴۶ (۱۸.۴%) cefoxitin-insensitive E. coli isolates, ۱۰ (۲۱.۷%)were positive for AmpC ?-lactamase genes, among them ۴ (۸.۶۹%) isolates were positive forblaDHA genes and ۶ (۱۳%) for blaCIT genes. Of ۵۷ (۳۰.۴%) cefoxitin-insensitive K. pneumoniaeisolates, ۱۰ (۱۷.۵%) were positive for AmpC gene with ۴ (۶.۳۴%) and ۶ (۹.۵%) isolates positivefor blaDHA and blaCIT genes, respectively. However, no MOX, ACC, FOX, or EBC genes weredetected in the isolates. Considering the results of diferent confrmatory phenotypic tests, the AmpCcefoxitin-EDTA test showed a higher discriminatory power for detecting AmpC ?-lactamaseproducingstrains. The specifcity and sensitivity of AmpC cefoxitin-EDTA were ۷۷%, ۱۰۰% forK. pneumonia and ۷۰%, ۹۰% for E. coli higher than the other two tests, respectively. Also, theauthors demonstrated high prevalence rate for resistance to certain antibiotics, such as cefuroxime,trimethoprim-sulfamethoxazole, ampicillin, and cefotaxime.Conclusion : In conclusion, our study provided valuable information regarding the plasmidmediatedAmpC β-lactamase gene content, antibiotic resistance, and confrmatory phenotypic testsfor AmpC β-lactamases in E. coli and K.pneumoniae isolates from clinical sources.

کلیدواژه ها

AmpC β-lactamases -Escherichia coli- Klebsiella pneumoniae

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