Department of Pharmaceutical Microbiology and Microbiological Diagnostic, Medical University of Lodz, Lodz, Poland.
Sci Rep. 2023 Aug 21;13(1):13629. doi: 10.1038/s41598-023-40866-3.
Multidrug-resistant coagulase-negative staphylococci represent a real therapeutic challenge. The aim of the study was to emphasize the importance of heteroresistance to vancomycin presence in methicillin-resistant strains of S. epidermidis. The research comprised 65 strains of S. epidermidis. Heteroresistance to vancomycin was detected with the use of the agar screening method with Brain Heart Infusion and a population profile analysis (PAP test). In addition, types of cassettes and genes responsible for resistance to antibiotics for 22 multidrug resistant strains were determined. Our investigations showed that 56 of 65 S. epidermidis strains were phenotypically resistant to methicillin. The tested strains were mostly resistant to erythromycin, gentamicin, clindamycin, and ciprofloxacin. Six strains showed decreased susceptibility to vancomycin and their heterogeneous resistance profiles were confirmed with the PAP test. All tested multi-resistant strains exhibited the mecA gene. More than half of them possessed type IV cassettes. ant(4')-Ia and aac(6')/aph(2''), ermC and tetK genes were most commonly found. The described phenomenon of heteroresistance to vancomycin in multidrug resistant bacteria of the Staphylococcus genus effectively inhibits a therapeutic effect of treatment with this antibiotic. That is why it is so important to search for markers that will enable to identify heteroresistance to vancomycin strains under laboratory conditions.
耐多药凝固酶阴性葡萄球菌是一个真正的治疗挑战。本研究的目的是强调耐甲氧西林表皮葡萄球菌中存在异质性万古霉素耐药的重要性。研究包括 65 株表皮葡萄球菌。使用含脑心浸液的琼脂筛选法和群体分析（PAP 试验）检测异质性万古霉素耐药性。此外，还确定了 22 株多药耐药菌株对抗生素耐药的盒型和基因。我们的研究表明，65 株表皮葡萄球菌中有 56 株表型对甲氧西林耐药。测试的菌株对红霉素、庆大霉素、克林霉素和环丙沙星的耐药性最强。6 株表现出对万古霉素的低敏感性，其异质性耐药谱通过 PAP 试验得到证实。所有测试的多耐药菌株均表现出 mecA 基因。其中一半以上携带 IV 型盒。最常见的是 ant(4')-Ia 和 aac(6')/aph(2'')、ermC 和 tetK 基因。描述的万古霉素异质性耐药现象在葡萄球菌属的多药耐药菌中有效地抑制了这种抗生素治疗的疗效。这就是为什么在实验室条件下寻找能够识别异质性万古霉素耐药菌株的标志物如此重要的原因。
