Genetic Characterization of Methicillin-ResistantStaphylococcus aureusIsolates from Human Bloodstream Infections: Detection of MLSBResistance
Genetic Characterization of Methicillin-ResistantStaphylococcus aureusIsolates from Human Bloodstream Infections: Detection of MLSBResistance
复制标题
DOI：
10.3390/antibiotics9070375
复制
发表时间：
2020-07-01
影响因子：
4.8
通讯作者：
Poeta, Patricia
中科院分区：
文献类型：
--
作者：
Silva, Vanessa;Hermenegildo, Sara;Poeta, Patricia
在这项研究中，我们旨在表征从血液感染中分离出的耐甲氧西林金黄色葡萄球菌（MRSA）的抗菌素耐药性以及分离物的相关遗传谱系。从2016年至2019年住院患者的菌血症样本中分离出16株MRSA。采用Kirby-Bauer纸片扩散法检测分离菌株对14种抗菌药物的敏感性。采用双盘扩散法（D-test）测定红霉素耐药菌株的大环内酯-林科胺-链霉素B （MLSB）耐药表型。采用聚合酶链反应（PCR）筛选抗性和毒力基因。所有分离株均经多位点序列分型（MLST）、spattyping、葡萄球菌染色体盒型（SCCmec）分型和辅助基因调节因子（agr）分型鉴定。分离株对头孢西丁、青霉素、环丙沙星、红霉素、夫西地酸、克林霉素和氨基糖苷类耐药，通过blaz、ermA、ermC、mphC、msrA/B、aac（6′）-Ie-aph（2′）-Ia和ant（4′）-Ia基因的存在证实。3株panton - valentine -leukocidin阳性。大多数菌株（n= 12）呈现诱导型MLS(B)表型。分离株为8个spa型（t747、t002、t020、t1084、t008、t10682、t18526和t1370）和4个MLSTs （ST22、ST5、ST105和ST8）。总体而言，大多数（n= 12） MRSA分离株具有可诱导MLS(B)表型的多药耐药谱，属于流行MRSA克隆。
In this study we aimed to characterize antimicrobial resistance in methicillin-resistantStaphylococcus aureus(MRSA) isolated from bloodstream infections as well as the associated genetic lineages of the isolates. Sixteen MRSA isolates were recovered from bacteremia samples from inpatients between 2016 and 2019. The antimicrobial susceptibility of these isolates was tested by the Kirby-Bauer disk diffusion method against 14 antimicrobial agents. To determine the macrolide-lincosamide-streptogramin B (MLSB) resistance phenotype of the isolates, erythromycin-resistant isolates were assessed by double-disk diffusion (D-test). The resistance and virulence genes were screened by polymerase chain reaction (PCR). All isolates were characterized by multilocus sequence typing (MLST),spatyping, staphylococcal chromosomal cassettemec(SCCmec) typing, and accessory gene regulator (agr) typing. Isolates showed resistance to cefoxitin, penicillin, ciprofloxacin, erythromycin, fusidic acid, clindamycin, and aminoglycosides, confirmed by the presence of theblaZ,ermA,ermC,mphC,msrA/B,aac(6')-Ie-aph(2'')-Ia, andant(4')-Ia genes. Three isolates were Panton-Valentine-leukocidin-positive. Most strains (n= 12) presented an inducible MLS(B)phenotype. The isolates were ascribed to eightspa-types (t747, t002, t020, t1084, t008, t10682, t18526, and t1370) and four MLSTs (ST22, ST5, ST105, and ST8). Overall, most (n= 12) MRSA isolates had a multidrug-resistance profile with inducible MLS(B)phenotypes and belonged to epidemic MRSA clones.