Dissemination of IncF plasmids carrying beta-lactamase genes in Gram-negative bacteria from Nigerian hospitals

作者：Ogbolu David Olusoga^*; Daini Oluwole Adebayo; Ogunledun Afolabi; Alli Oyebode A Terry; Webber Mark A

来源：Journal of Infection in Developing Countries, 2013, 7(5): 382-390.

DOI：10.3855/jidc.2613

• ESBL
• plasmid
• resistant genes
• bacteria
• Nigeria

Introduction: Production of beta-lactamases is the predominant cause of resistance to beta-lactam antibiotics in Gram-negative bacteria. We investigated the diversity of plasmid-borne beta-lactamase genes and replicon type of the plasmids carrying the respective genes in Gram-negative bacteria recovered from clinical infection in Nigerian hospitals. %26lt;br%26gt;Methodology: A total of 134 Gram-negative bacteria of 13 species were analyzed for antimicrobial susceptibility, phenotypic and genotypic detection of various beta-lactamases, and plasmid analysis, including replicon typing. %26lt;br%26gt;Results: Of the 134 isolates, 111 (82.8%) contained beta-lactamases, while 28 (20.9%) carried extended-spectrum beta-lactamases. PCR and sequencing identified TEM-1 in 109 isolates (81.3%), SHV-1 in 33 isolates (24.6%), OXA-1 in 15 isolates (11.2%) and CTX-M enzymes (24 CTX-M-15 and 1 CTX-M-3) in 25 isolates (18.7%). Multiplex PCR showed that 6 isolates carried plasmidic AmpCs (ACT-1, DHA-1 and CMY-2); these enzymes were detected only in isolates possessing CTX-M beta-lactamases. Of 13 (76.9%) representative plasmids investigated in detail, 9 (69.2%) were self-transferable when selected by a beta-lactam and the plasmids once transferred coded for beta-lactam resistance. Replicon typing indicated IncF as the common vector encoding for beta-lactamases. %26lt;br%26gt;Conclusions: The study showed a diversity of beta-lactamase genes disseminated by conjugative IncF plasmids in Gram-negative bacteria; TEM-1, SHV-1, OXA-1, CTX-M-15, CTX-M-3and plasmidic AmpC enzymes are in common circulation in Nigeria.

• 出版日期2013-5