Rossi Ciro César, da Silva Dias Ingrid, Muniz Igor Mansur, Lilenbaum Walter, Giambiagi-deMarval Marcia
Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, RJ, Brazil.
Departamento de Medicina Veterinária - Universidade Federal de Rondonia, RO, Brazil.
Vet Microbiol. 2017 Mar;201:136-140. doi: 10.1016/j.vetmic.2017.01.029. Epub 2017 Jan 25.
This study aimed to characterize the species, antimicrobial resistance and dispersion of CRISPR systems in staphylococci isolated from the oropharynx of domestic cats in Brazil. Staphylococcus strains (n=75) were identified by MALDI-TOF and sequencing of rpoB and tuf genes. Antimicrobial susceptibility was assessed by disk diffusion method and PCR to investigate the presence of antimicrobial-resistance genes usually present in mobile genetic elements (plasmids), in addition to plasmid extraction. CRISPR - genetic arrangements that give the bacteria the ability to resist the entry of exogenous DNA - were investigated by the presence of the essential protein Cas1 gene. A great diversity of Staphylococcus species (n=13) was identified. The presence of understudied species, like S. nepalensis and S. pettenkoferi reveals that more than one identification method may be necessary to achieve conclusive results. At least 56% of the strains contain plamids, being 99% resistant to at least one of the eight tested antimicrobials and 12% multidrug resistant. CRISPR were rare among the studied strains, consistent with their putative role as gene reservoirs. Moreover, herein we describe for the first time their existence in Staphylococcus lentus, to which the system must confer additional adaptive advantage. Prevalence of resistance among staphylococci against antimicrobials used in veterinary and human clinical practice and the zoonotic risk highlight the need of better antimicrobial management practices, as staphylococci may transfer resistance genes among themselves, including to virulent species, like S. aureus.
本研究旨在对从巴西家猫口咽部分离出的葡萄球菌中的CRISPR系统的种类、抗微生物耐药性和分布特征进行描述。通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）以及rpoB和tuf基因测序对葡萄球菌菌株（n = 75）进行鉴定。采用纸片扩散法评估抗微生物敏感性，并进行PCR检测以调查通常存在于可移动遗传元件（质粒）中的抗微生物耐药基因的存在情况，此外还进行了质粒提取。通过必需蛋白Cas1基因的存在情况对CRISPR（赋予细菌抵抗外源DNA进入能力的基因排列）进行研究。鉴定出了种类繁多的葡萄球菌（n = 13）。像尼泊尔葡萄球菌和佩滕科费尔葡萄球菌等研究较少的种类的存在表明，可能需要不止一种鉴定方法才能获得确凿的结果。至少56%的菌株含有质粒，99%的菌株对所测试的八种抗微生物药物中的至少一种耐药，12%的菌株具有多重耐药性。CRISPR在所研究的菌株中很罕见，这与其作为基因库的假定作用一致。此外，我们在此首次描述了它们在缓慢葡萄球菌中的存在，该系统必定赋予了这种葡萄球菌额外的适应性优势。葡萄球菌对兽医和人类临床实践中使用的抗微生物药物的耐药性流行情况以及人畜共患病风险凸显了更好的抗微生物管理措施的必要性，因为葡萄球菌可能在自身之间转移耐药基因，包括转移给像金黄色葡萄球菌这样的致病菌种。
