Jackson Charlene R, Fedorka-Cray Paula J, Barrett John B, Ladely Scott R
Antimicrobial Resistance Research Unit, USDA-ARS, Russell Research Center, Athens, GA 30605, USA.
Avian Dis. 2004 Jan-Mar;48(1):100-7. doi: 10.1637/7071.
Approximately 46% (75/162) or poultry enterococci collected between 1999 and 2000 exhibited high-level resistance to gentamicin (minimum inhibitory concentration [MIC] > or = 500 microg/ml), kanamycin (MIC > or = 500 microg/ml), or streptomycin (MIC > or = 1000 microg/ml). Forty-one percent of the isolates were resistant to kanamycin (n = 67), whereas 23% and 19% were resistant to genramicin (n = 37) and streptomycin (n = 31), respectively. The predominant species identified was Enterococcus faecium (n = 105), followed by Enterococcus faecalis (n = 40) and Enterococcus durans (n = 8). Using polymerase chain reaction, the isolates were examined for the presence of 10 aminoglycoside resistance genes [ant(6)-Ia, ant(9)-Ia, ant(4')-Ia, aph(3')-IIIa, aph(2")-Ib, aph(2")-Ic, aph(2")-Id, aac(6')-Ie-aph(2")-Ia, and aac(6')-Ii]. Five aminoglycoside resistance genes were detected, most frequently aac(6')-Ii and ant(6)-Ia from E. faecium. Seven E. faecalis isolates resistant to gentamicin, kanamycin, or streptomycin were negative for all genes tested, indicating that additional resistance genes may exist. Phylogenetic analysis revealed that the isolates were genetically different with little clonality. These data indicate that enterococci from poultry are diverse and contain potentially unidentified aminoglycoside resistance genes.
1999年至2000年间收集的约46%（75/162）的家禽肠球菌对庆大霉素（最低抑菌浓度[MIC]≥500μg/ml）、卡那霉素（MIC≥500μg/ml）或链霉素（MIC≥1000μg/ml）表现出高水平耐药。41%的分离株对卡那霉素耐药（n = 67），而分别有23%和19%的分离株对庆大霉素（n = 37）和链霉素（n = 31）耐药。鉴定出的主要菌种是屎肠球菌（n = 105），其次是粪肠球菌（n = 40）和耐久肠球菌（n = 8）。使用聚合酶链反应检测分离株中10种氨基糖苷类耐药基因[ant(6)-Ia、ant(9)-Ia、ant(4')-Ia、aph(3')-IIIa、aph(2")-Ib、aph(2")-Ic、aph(2")-Id、aac(6')-Ie-aph(2")-Ia和aac(6')-Ii]的存在情况。检测到5种氨基糖苷类耐药基因，最常见的是来自屎肠球菌的aac(6')-Ii和ant(6)-Ia。7株对庆大霉素、卡那霉素或链霉素耐药的粪肠球菌分离株所有检测基因均为阴性，表明可能存在其他耐药基因。系统发育分析表明，分离株在基因上存在差异，克隆性较低。这些数据表明，家禽来源的肠球菌具有多样性，并且含有潜在未鉴定的氨基糖苷类耐药基因。
