Manandhar Sarita, Shrestha Raju, Tuladhar Ratna Shova, Lekhak Sunil
Department of Microbiology, TriChandra Multiple College, Tribhuvan University, Kathmandu 44600, Nepal.
Department of Microbiology, National College, Khushibun, Kathmandu 44611, Nepal.
Infect Dis Rep. 2021 Dec 7;13(4):1043-1052. doi: 10.3390/idr13040095.
Resistance to antibiotics, biofilm formation and the presence of virulence factors play important roles in increased mortality associated with infection by staphylococci. The macrolide lincosamide streptogramin B (MLS) family of antibiotics is commonly used to treat infections by methicillin-resistant isolates. Clinical failure of clindamycin therapy has been reported due to multiple mechanisms that confer resistance to MLS. This study aims to find the incidence of different phenotypes of MLS resistance and biofilm production among staphylococci. A total of 375 staphylococci were isolated from different clinical samples, received from two tertiary care hospitals in Nepal. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by D test, according to CLSI guidelines. Biofilm formation was detected by the tissue culture plate method and PCR was used to detect genes. Of the total staphylococci isolates, 161 (42.9%) were with 131 (81.4%) methicillin-resistant strains, and 214 (57.1%) isolates were coagulase-negative staphylococci, with 143 (66.8%) methicillin-resistant strains. The overall prevalence of constitutive MLS (cMLS) and inducible MLS (iMLS) phenotypes was 77 (20.5%) and 87 (23.2%), respectively. Both iMLS and cMLS phenotypes predominated in methicillin-resistant isolates. The tissue culture plate method detected biofilm formation in 174 (46.4%) isolates and genes in 86 (22.9%) isolates. Among biofilm producing isolates, cMLS and iMLS phenotypes were 35 (20.1%) and 27 (15.5%), respectively. The cMLS and iMLS were 11 (12.8%) and 19 (22.1%), respectively, in isolates possessing genes. Clindamycin resistance in the form of cMLS and iMLS, especially among MRSA, emphasizes the need for routine D tests to be performed in the lab.
抗生素耐药性、生物膜形成以及毒力因子的存在在葡萄球菌感染相关死亡率增加中起重要作用。大环内酯 - 林可酰胺 - 链阳菌素B（MLS）类抗生素常用于治疗耐甲氧西林菌株引起的感染。由于多种赋予对MLS耐药性的机制，已报道了克林霉素治疗的临床失败情况。本研究旨在找出葡萄球菌中MLS耐药性和生物膜产生的不同表型的发生率。从尼泊尔两家三级护理医院接收的不同临床样本中总共分离出375株葡萄球菌。根据CLSI指南，采用头孢西丁纸片扩散法检测耐甲氧西林情况，采用D试验检测诱导型克林霉素耐药性。采用组织培养板法检测生物膜形成，并使用PCR检测基因。在总共分离出的葡萄球菌中，161株（42.9%）为葡萄球菌，其中131株（81.4%）为耐甲氧西林菌株，214株（57.1%）分离株为凝固酶阴性葡萄球菌，其中143株（66.8%）为耐甲氧西林菌株。组成型MLS（cMLS）和诱导型MLS（iMLS）表型的总体患病率分别为77（20.5%）和87（23.2%）。iMLS和cMLS表型在耐甲氧西林分离株中占主导地位。组织培养板法在174株（46.4%）分离株中检测到生物膜形成，在86株（22.9%）分离株中检测到基因。在产生生物膜的分离株中，cMLS和iMLS表型分别为35（20.1%）和27（15.5%）。在拥有基因的分离株中，cMLS和iMLS分别为11（12.8%）和19（22.1%）。以cMLS和iMLS形式存在的克林霉素耐药性，尤其是在耐甲氧西林金黄色葡萄球菌中，强调了实验室进行常规D试验的必要性。
