Marosevic D, Cervinkova D, Vlkova H, Videnska P, Babak V, Jaglic Z
Veterinary Research Institute, Brno, Czech Republic.
Veterinary Research Institute, Brno, Czech Republic.
Vet Microbiol. 2014 Jul 16;171(3-4):388-96. doi: 10.1016/j.vetmic.2013.12.017. Epub 2014 Jan 3.
The influence of specific and non-specific antibiotic pressure on in vivo spread of macrolide-lincosamide-streptogramin B (MLSB) resistance was evaluated in this study. Chickens repeatedly inoculated with Enterococcus faecalis harbouring the plasmid pAMβ1 carrying the erm(B) gene were perorally treated for one week with tylosin, lincomycin (both specific antibiotic pressure) and chlortetracycline (non-specific antibiotic pressure). Antibiotic non-treated but E. faecalis inoculated chickens served as a control. To quantify the erm(B) gene and characterise intestinal microflora, faecal DNA was analysed by qPCR and 454-pyrosequencing. Under the pressure of antibiotics, a significant increase in erm(B) was observed by qPCR. However, at the final stage of the experiment, an increase in erm(B) was also observed in two out of five non-treated chickens. In chickens treated with tylosin and chlortetracycline, the increase in erm(B) was accompanied by an increase in enterococci. However, E. faecalis was at the limit of detection in all animals. This suggests that the erm(B) gene spread among the gut microbiota other than E. faecalis. Pyrosequencing results indicated that, depending on the particular antibiotic pressure, different bacteria could be responsible for the spread of MLSB resistance. Different species of MLSB-resistant enterococci and streptococci were isolated from cloacal swabs during and after the treatment. PFGE analysis of MLSB-resistant enterococci revealed four clones, all differing from the challenge strain. All of the MLSB-resistant isolates harboured a plasmid of the same size as pAMβ1. This study has shown that MLSB resistance may spread within the gut microbiota under specific and non-specific pressure and even in the absence of any antimicrobial pressure. Finally, depending on the particular antibiotic pressure, different bacterial species seems to be involved in the spread of MLSB resistance.
本研究评估了特异性和非特异性抗生素压力对大环内酯-林可酰胺-链阳霉素B（MLSB）耐药性体内传播的影响。用携带erm(B)基因的质粒pAMβ1的粪肠球菌反复接种鸡，然后分别用泰乐菌素、林可霉素（均为特异性抗生素压力）和金霉素（非特异性抗生素压力）进行为期一周的口服治疗。未接受抗生素治疗但接种了粪肠球菌的鸡作为对照。为了量化erm(B)基因并表征肠道微生物群，通过qPCR和454焦磷酸测序分析粪便DNA。在抗生素压力下，通过qPCR观察到erm(B)显著增加。然而，在实验的最后阶段，五只未治疗的鸡中有两只也观察到erm(B)增加。在用泰乐菌素和金霉素治疗的鸡中，erm(B)的增加伴随着肠球菌的增加。然而，在所有动物中粪肠球菌均处于检测限。这表明erm(B)基因在除粪肠球菌之外的肠道微生物群中传播。焦磷酸测序结果表明，根据特定的抗生素压力，不同的细菌可能是MLSB耐药性传播的原因。在治疗期间和治疗后，从泄殖腔拭子中分离出不同种类的耐MLSB的肠球菌和链球菌。对耐MLSB的肠球菌进行PFGE分析，发现了四个克隆，均与攻击菌株不同。所有耐MLSB的分离株都含有与pAMβ1大小相同的质粒。本研究表明，MLSB耐药性可能在特异性和非特异性压力下，甚至在没有任何抗菌压力的情况下在肠道微生物群中传播。最后，根据特定的抗生素压力，不同的细菌种类似乎参与了MLSB耐药性的传播。
