Sirichoat Auttawit, Flórez Ana Belén, Vázquez Lucía, Buppasiri Pranom, Panya Marutpong, Lulitanond Viraphong, Mayo Baltasar
Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa, Spain.
Department of Microbiology, Research and Diagnostic Center for Emerging Infectious Diseases (RCEID), Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Front Microbiol. 2020 Jun 26;11:1438. doi: 10.3389/fmicb.2020.01438. eCollection 2020.
The spread of antibiotic resistance is a major public health concern worldwide. Commensal bacteria from the human genitourinary tract can act as reservoirs of resistance genes playing a role in their transfer to pathogens. In this study, the minimum inhibitory concentration of 16 antibiotics to 15 isolates from the human vagina, identified as , , and , was determined. Eight isolates were considered resistant to tetracycline, five to clindamycin and quinupristin-dalfopristin, and four to rifampicin. To investigate the presence of antimicrobial resistance genes, PCR analysis was performed in all isolates, and five were subjected to whole-genome sequencing analysis. PCR reactions identified (M) in all tetracycline-resistant isolates, while both (M) and (L) were found in tetracycline-resistant isolates. The (M) gene in VA02-2 was carried within an entire copy of the transposon Tn. In VA01-10AN and VA01-14AN, the (M) and (L) genes were found contiguous with one another and flanked by genes encoding DNA mobilization and plasmid replication proteins. Amplification and sequencing suggested the gene to be complete in all isolates resistant to clindamycin and quinupristin-dalfopristin, while the gene contain mutations rendering to a non-functional LsaA in susceptible isolates. These results were subsequently confirmed by genome analysis of clindamycin and quinupristin-dalfopristin resistant and susceptible strains. Although a clinical breakpoint to kanamycin for has yet to be established, VA08-2AN showed an MIC to this antibiotic of 128 μg mL. However, genes involved in kanamycin resistance were not identified. Under the assayed conditions, neither (L) nor (M) from either or was transferred by conjugation to recipient strains of , , or . Nonetheless, the (L) gene from VA01-10AN was amplified by PCR, and cloned and expressed in , to which it provided a resistance of 48-64 μg mL to tetracycline. Our results expand the knowledge of the antibiotic resistance-susceptibility profiles of vaginal bacteria and provide the genetic basis of their intrinsic and acquired resistance.
抗生素耐药性的传播是全球主要的公共卫生问题。人类泌尿生殖道的共生细菌可作为耐药基因的储存库，在耐药基因向病原体的转移中发挥作用。在本研究中，测定了16种抗生素对15株从人阴道分离出的、鉴定为[具体菌种1]、[具体菌种2]和[具体菌种3]的菌株的最低抑菌浓度。8株菌株对四环素耐药，5株对克林霉素和奎奴普丁 - 达福普汀耐药，4株对利福平耐药。为了研究抗菌耐药基因的存在情况，对所有分离株进行了PCR分析，并对其中5株进行了全基因组测序分析。PCR反应在所有对四环素耐药的[具体菌种1]分离株中鉴定出[具体基因1]（M），而在对四环素耐药的[具体菌种2]分离株中同时发现了[具体基因1]（M）和[具体基因2]（L）。VA02 - 2中的[具体基因1]（M）基因存在于转座子Tn的一个完整拷贝内。在VA01 - 10AN和VA01 - 14AN中，[具体基因1]（M）和[具体基因2]（L）基因彼此相邻，两侧是编码DNA移动和质粒复制蛋白的基因。扩增和测序表明，在所有对克林霉素和奎奴普丁 - 达福普汀耐药的[具体菌种3]分离株中，[具体基因3]基因是完整的，而在敏感分离株中，该基因含有导致LsaA无功能的突变。这些结果随后通过对克林霉素和奎奴普丁 - 达福普汀耐药和敏感的[具体菌种3]菌株的基因组分析得到证实。尽管针对[具体菌种3]的卡那霉素临床断点尚未确定，但VA08 - 2AN对该抗生素的最低抑菌浓度为128μg/mL。然而，未鉴定出与卡那霉素耐药相关的基因。在测定条件下，无论是[具体菌种1]还是[具体菌种2]的[具体基因2]（L）或[具体基因1]（M）都未通过接合转移到[受体菌种1]、[受体菌种2]或[受体菌种3]的受体菌株中。尽管如此，VA01 - 10AN中的[具体基因2]（L）基因通过PCR扩增，并克隆和表达于[受体菌种4]中，它赋予[受体菌种4]对四环素48 - 64μg/mL的耐药性。我们的结果扩展了对阴道细菌抗生素耐药性 - 敏感性谱的认识，并为其固有和获得性耐药性提供了遗传基础。
Zotero 插件