Molecular characterization of antimicrobial resistance in Gram-negative bacteria isolated from bovine mastitis in Egypt
Molecular characterization of antimicrobial resistance in Gram-negative bacteria isolated from bovine mastitis in Egypt
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DOI：
10.1111/j.1348-0421.2011.00323.x
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发表时间：
2011-05-01
影响因子：
2.6
通讯作者：
Shimamoto, Tadashi
中科院分区：
文献类型：
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作者：
Ahmed, Ashraf M.;Shimamoto, Tadashi
本研究的目的是表征从埃及牛乳腺炎病例中分离出的革兰氏阴性细菌的多重耐药性的遗传基础。 112 株革兰氏阴性细菌分离株中，有 34 株（30.4%）被发现具有多重耐药表型，这些细菌至少含有一种抗菌素耐药基因。最常见的多重耐药 (MDR) 菌种是阴沟肠杆菌（8 个分离株，7.1%）、肺炎克雷伯菌（7 个分离株，6.3%）、产酸克雷伯菌（7 个分离株，6.3%）、大肠杆菌（5 个分离株，4.5%）和弗氏柠檬酸杆菌（3 个分离株，2.7%）。最常见的耐药表型是氨苄青霉素（97.0%）、链霉素（94.1%）、四环素（91.2%）、甲氧苄啶-磺胺甲恶唑（88.2%）、萘啶酸（85.3%）和氯霉素（76.5%）。在 28 个分离株 (25.0%) 中检测到 1 类整合子。 1类整合子内的基因盒包括编码甲氧苄啶(dfrA1、dfrA5、dfrA7、dfrA12、dfrA15、dfrA17和dfrA25)、氨基糖苷类(aadA1、aadA2、aadA5、aadA7、aadA12、aadA22和aac(3)-Id)抗性的基因盒，氯霉素 (cmlA)、红霉素 (ereA2) 和利福平 (arr-3)。在具有三种不同特征的 6 个分离株 (5.4%) 中鉴定出 2 类整合子。此外，还鉴定了β-内酰胺酶编码基因bla(TEM)、bla(SHV)、bla(CTX-M)和bla(OXA)、质粒介导的喹诺酮抗性基因qnr和aac(6)-Ib-cr以及氟苯尼考抗性基因floR。据我们所知，结果首次从乳腺炎病例中鉴定出 2 类整合子、qnr 和 aac(6)-Ib-cr。这是从非洲牛乳腺炎中分离出的革兰氏阴性细菌抗菌药物耐药性分子特征的第一份报告。
The aim of this study was to characterize the genetic basis of multidrug resistance in Gram-negative bacteria isolated from bovine mastitis cases in Egypt. Multidrug resistance phenotypes were found in 34 of 112 (30.4%) Gram-negative bacterial isolates, which harbored at least one antimicrobial resistance gene. The most prevalent multidrug-resistant (MDR) species were Enterobacter cloacae (8 isolates, 7.1%), Klebsiella pneumoniae (7 isolates, 6.3%), Klebsiella oxytoca (7 isolates, 6.3%), Escherichia coli (5 isolates, 4.5%), and Citrobacter freundii (3 isolates, 2.7%). The most commonly observed resistance phenotypes were against ampicillin (97.0%), streptomycin (94.1%), tetracycline (91.2%), trimethoprim-sulfamethoxazole (88.2%), nalidixic acid (85.3%), and chloramphenicol (76.5%). Class 1 integrons were detected in 28 (25.0%) isolates. The gene cassettes within class 1 integrons included those encoding resistance to trimethoprim (dfrA1, dfrA5, dfrA7, dfrA12, dfrA15, dfrA17, and dfrA25), aminoglycosides (aadA1, aadA2, aadA5, aadA7, aadA12, aadA22, and aac(3)-Id), chloramphenicol (cmlA), erythromycin (ereA2), and rifampicin (arr-3). Class 2 integrons were identified in 6 isolates (5.4%) with three different profiles. Furthermore, the beta-lactamase encoding genes, bla(TEM), bla(SHV), bla(CTX-M), and bla(OXA), the plasmid-mediated quinolone resistance genes, qnr and aac(6)-Ib-cr, and the florfenicol resistance gene, floR, were also identified. To the best of our knowledge, the results identified class 2 integrons, qnr and aac(6)-Ib-cr from cases of mastitis for the first time. This is the first report of molecular characterization for antimicrobial resistance in Gram-negative bacteria isolated from bovine mastitis in Africa.