Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, MS 39762, USA.
Lett Appl Microbiol. 2010 Jun 1;50(6):626-32. doi: 10.1111/j.1472-765X.2010.02843.x. Epub 2010 Mar 24.
To investigate the susceptibility of 221 Listeria spp. (86 Listeria monocytogenes, 41 Listeria innocua and 94 Listeria seeligeri-Listeria welshimeri-Listeria ivanovii) isolated from catfish fillets and processing environment to 15 antibiotics.
Listeria isolates were analysed by disc-diffusion assay for their resistance to 15 drugs. All isolates were resistant to cefotaxime and clindamycin but were sensitive to ampicillin, cephalothin, chloramphenicol, erythromycin, gentamycin, kanamycin, rifampin, streptomycin, sulfamethoxazole/trimethoprim and vancomycin. Unlike L. monocytogenes and L. seeligeri-L. welshimeri-L. ivanovii isolates, 22% of L. innocua isolates displayed tetracycline/oxytetracycline resistance. Screening of tet genes by PCR identified tet(M) gene in the chromosome of all tetracycline/oxytetracycline-resistant L. innocua. However, this gene was not associated with the integrase gene of Tn1545. Repetitive extragenic palindromic- and enterobacterial repetitive intergenic consensus-PCR typing methods showed no genotype-specific tetracycline resistance in the tet(M)-positive strains.
Catfish fillets and processing environment were currently free of L. monocytogenes resistant to antibiotics commonly used in human listeriosis treatment. However, the presence of tet(M) gene in L. innocua raises the possibility of future acquisition of resistance by L. monocytogenes.
These data will be helpful in improving background data on antibiotics resistance strains isolated from food and processing environment.
研究 221 株李斯特菌（86 株单核细胞增生李斯特菌、41 株无害李斯特菌和 94 株李斯特菌 seeligeri-李斯特菌 welshimeri-李斯特菌 ivanovii）对 15 种抗生素的敏感性。
采用药敏纸片扩散法分析李斯特菌分离株对 15 种药物的耐药性。所有分离株均对头孢噻肟和克林霉素耐药，但对氨苄西林、头孢噻吩、氯霉素、红霉素、庆大霉素、卡那霉素、利福平、链霉素、磺胺甲噁唑/甲氧苄啶和万古霉素敏感。与单核细胞增生李斯特菌和李斯特菌 seeligeri-李斯特菌 welshimeri-李斯特菌 ivanovii 分离株不同，22%的无害李斯特菌分离株表现出四环素/土霉素耐药性。PCR 检测 tet 基因发现，所有四环素/土霉素耐药的无害李斯特菌分离株的染色体中均存在 tet(M)基因。然而，该基因与 Tn1545 的整合酶基因无关。重复外显子回文和肠细菌重复基因间共识-PCR 分型方法显示，tet(M)阳性株无特定基因型的四环素耐药性。
目前，鲶鱼片及其加工环境中不存在对人类李斯特菌病治疗常用抗生素耐药的单核细胞增生李斯特菌。然而，无害李斯特菌中 tet(M)基因的存在增加了李斯特菌获得耐药性的可能性。
这些数据将有助于改善食品和加工环境中分离的抗生素耐药菌株的背景数据。
