Latif Mahwish, Usman Javaid, Gilani Mehreen, Munir Tehmina, Mushtaq Maria, Anjum Rabia
Department of Microbiology, Army Medical College Rawalpindi, National University of Sciences and Technology Islamabad, Pakistan.
J Pak Med Assoc. 2015 Mar;65(3):283-6.
To determine the frequency of isolation of coagulase-negative staphylococci and their resistance to methicillin over a period of time.
The descriptive cross-sectional study was carried out at Army Medical College, Rawalpindi, from June 2009 to May 2012, and comprised clinical samples mostly from patients admitted to the intensive care unit. They were inoculated onto appropriate culture media depending upon the specimen. After 24-hour incubation at 35°C, coagulase-negative staphylococci were identified on the basis of colony morphology, gram staining, a positive catalase and a negative tube coagulase test.Methicillin resistance among the isolated staphylococci was determined using a 30µg Cefoxitin disc as per the Clinical and Laboratory Standards Institute protocol. Number of coagulase-negative staphylococci for each year and their methicillin resistance rates were calculated. A comparison was made with methicillin resistant staphylococcus aureus) isolated during the same period.
Of the total 1331 specimens studies over three years, 581(43.65%) were coagulase-negative staphylococci. The rate of coagulase-negative staphylococci and methicillin resistance was higher each year; 110(26.6%) in May 2009-Jun 2010, 134(36.5%) in 2011, and 337(61%) in 2012. Methicillin resistance rates also increased from 25(22.7%) to 46(34.3%) and then to 201(59.6%) in 2012.Maximum isolated specimens came from blood 311(53.5%), followed by pus/swabs 204(35.1%).
The frequency of isolation of coagulase-negative staphylococci and its methicillin resistance among hospitalised patients is on the rise.
确定一段时间内凝固酶阴性葡萄球菌的分离频率及其对甲氧西林的耐药性。
2009年6月至2012年5月在拉瓦尔品第陆军医学院开展描述性横断面研究，研究对象主要为重症监护病房收治患者的临床样本。根据样本类型将其接种到合适的培养基上。在35℃孵育24小时后，根据菌落形态、革兰氏染色、过氧化氢酶阳性和试管凝固酶试验阴性来鉴定凝固酶阴性葡萄球菌。按照临床和实验室标准协会的方案，使用30μg头孢西丁纸片测定分离出的葡萄球菌中的甲氧西林耐药性。计算每年凝固酶阴性葡萄球菌的数量及其甲氧西林耐药率。并与同期分离出的耐甲氧西林金黄色葡萄球菌进行比较。
在三年研究的总共1331份样本中，581份（43.65%）为凝固酶阴性葡萄球菌。每年凝固酶阴性葡萄球菌及其甲氧西林耐药率均较高；2009年5月至2010年6月为110份（26.6%），2011年为134份（36.5%），2012年为337份（61%）。甲氧西林耐药率也从25份（22.7%）增至46份（34.3%），然后在2012年增至201份（59.6%）。分离样本最多的来源是血液311份（53.5%），其次是脓液/拭子204份（35.1%）。
住院患者中凝固酶阴性葡萄球菌的分离频率及其甲氧西林耐药性呈上升趋势。
