Roy S, Barman T K, Hossain M A, Paul S K, Haque N, Ahmed S, Nasreen S A, Hossain M S, Sarkar S R, Kubayashi N, Laskar N
Dr Sangjukta Roy, Lecturer, Department of Microbiology, Mymensingh Medical College (MMC), Mymensingh, Bangladesh.
Mymensingh Med J. 2017 Jan;26(1):37-44.
Infections caused by Staphylococcus aureus were treated by methicillin, but about 95% of S. aureus has been resistance to methicillin, both in the community and hospitals and are increasing day by day. MRSA produces altered penicillin binding protein, PBP2a, due to the expression of mecA gene. Some strains of both the MRSA and MSSA carry PVL gene. This cross sectional observational study was conducted to detect the molecular-characterization of methicillin resistant Staphylococcus aureus (MRSA) and carried out in the Department of Microbiology, Mymensingh Medical College from July 2014 to December 2015. Clinical samples for this study were wound swab, pus, exudates from diabetic ulcer and burn ulcer, aural swab, blood and urine which were collected from three tertiary care hospitals such as from MMCH, BIRDEM hospital and SSMCH. Standard microbiological procedure & biochemical tests were carried out to detect S. aureus. Oxacillin disk diffusion method (ODDM) was done by Kirby-Bauer disk diffusion method. Out of a total 109 culture positive samples 69 isolates of S. aureus were selected for the study. Among the 69 isolates 33, 27 and 09 were from MMCH, BIRDEM hospital and SSMCH respectively. Among the 69 isolates, 17(24.6%) and 52(75.3%) were distinguished as MRSA and MSSA respectively by ODDM. In contrast, detection of presence and absence of mecA gene by PCR identified 20(28.9%) and 49(71.01%) isolates as MRSA and MSSA respectively. Multiplex PCR was performed by standard protocol with specific primers for detection of 16S rRNA gene for Staphylococcus, nuc gene for Staphylococcus aureus, mecA gene for MRSA, PVL gene as a virulence factor and ACME-arc gene for worldwide spreading USA 300 MRSA clone. The PVL gene were detected in 3 out of 20 MRSA (15%) and 19 out of 49 MSSA (38.7%) and the ACME- arc gene was not found in any isolates. All of the S. aureus (MRSA and MSSA) isolates were sensitive to Vancomycin and Gentamicin. All MRSA isolates (100%) showed resistance to Penicillin and Oxacillin. Of the MRSA isolates about 88.2% were resistance to Ceftazidime, 64.7% were resistance to Erythromycin and Ciprofloxacin, 11.7% were resistance to Tetracycline. Among the MSSA isolates 94.2% were resistance to Penicillin and 9.6% resistance to Ciprofloxacin. The MSSA were less resistance for non-beta lactam drugs than MRSA.
金黄色葡萄球菌引起的感染过去用甲氧西林治疗，但如今在社区和医院中，约95%的金黄色葡萄球菌已对甲氧西林耐药，且耐药情况日益增加。耐甲氧西林金黄色葡萄球菌（MRSA）由于mecA基因的表达产生了改变的青霉素结合蛋白PBP2a。MRSA和甲氧西林敏感金黄色葡萄球菌（MSSA）的一些菌株携带杀白细胞毒素（PVL）基因。本横断面观察性研究旨在检测耐甲氧西林金黄色葡萄球菌（MRSA）的分子特征，于2014年7月至2015年12月在迈门辛医学院微生物学系开展。本研究的临床样本为伤口拭子、脓液、糖尿病溃疡和烧伤溃疡的渗出液、耳拭子、血液和尿液，这些样本取自三家三级医疗机构，如迈门辛医学院医院（MMCH）、孟加拉国医学研究与发展中心医院（BIRDEM）和沙阿·舒贾医院（SSMCH）。采用标准微生物学程序和生化试验来检测金黄色葡萄球菌。苯唑西林纸片扩散法（ODDM）采用柯氏纸片扩散法进行。在总共109份培养阳性样本中，选取了69株金黄色葡萄球菌分离株进行研究。在这69株分离株中，分别有33株、27株和9株来自MMCH、BIRDEM医院和SSMCH。在这69株分离株中，通过ODDM分别鉴定出17株（24.6%）为MRSA，52株（75.3%）为MSSA。相比之下，通过聚合酶链反应（PCR）检测mecA基因的有无，分别鉴定出20株（28.9%）为MRSA，49株（71.01%）为MSSA。采用标准方案进行多重PCR，使用特异性引物检测葡萄球菌的16S核糖体RNA（rRNA）基因、金黄色葡萄球菌的nuc基因、MRSA的mecA基因、作为毒力因子的PVL基因以及用于全球传播的美国300株MRSA克隆的ACME - arc基因。在20株MRSA中有3株（15%）检测到PVL基因，在49株MSSA中有19株（38.7%）检测到PVL基因，且在任何分离株中均未发现ACME - arc基因。所有金黄色葡萄球菌（MRSA和MSSA）分离株对万古霉素和庆大霉素敏感。所有MRSA分离株（100%）对青霉素和苯唑西林耐药。在MRSA分离株中，约88.2%对头孢他啶耐药，64.7%对红霉素和环丙沙星耐药，11.7%对四环素耐药。在MSSA分离株中，94.2%对青霉素耐药，9.6%对环丙沙星耐药。MSSA对非β - 内酰胺类药物的耐药性低于MRSA。
