Taiwo S S, Bamidele M, Omonigbehin E A, Akinsinde K A, Smith S I, Onile B A, Olowe A O
Department of Medical Microbiology and Parasitology, University of llorin Teaching Hospital, Nigeria.
West Afr J Med. 2005 Apr-Jun;24(2):100-6.
Nosocomial infections caused by methicillin-resistant strains of Staphylococcus aureus constitute significant epidemiologic problems. Defining an outbreak requires the use of rapid and highly discriminatory epidemiologic methods to determine the epidemic strains involved in such outbreak.
A descriptive laboratory based surveillance study for MRSA was undertaken. One hundred and forty seven Staphylococcus aureus isolates from clinical specimens were screened for methicillin resistance at the University of Ilorin Teaching Hospital between January and December 2001. Fifty one (34.7%) methicillin resistant strains recovered were epidemiologically characterized using Eco R1 restriction enzyme analysis of their plasmid DNAs.
Forty five (88.2%) MRSA isolates were associated with infections and 6 (11.8 %) were colonizing strains; 36 (70.6%) and 15 (29.4%) were hospital and community acquired respectively. Skin and soft tissues were sites of infection in 36 (70.6 %) cases and surgical, emergency and ICU accounted for 33 (64.7%) isolates. All isolates were resistant to more than two antibiotics but sensitive to vancomycin. Forty two (82.4 %) isolates contained plasmids including 9 (21.4 %) that contained more than one plasmid. Restriction Enzyme Analysis of the Plasmid DNA (REAP) divided the isolates into 9 Eco R1 profiles, with profile 2 accounting for 41.7% of all nosocomial infections in the wards, implying that it is endemic. The remaining nosocomial profiles occurred less frequently, suggesting that they are sporadic strains originating from outside the hospital. The community strains showed diverse digestion pattern indicating that they are from different clones.
The spread of MRSA can be controlled through reinforcement of appropriate use of antibiotics, hand washing and laboratory surveillance for MRSA, particularly in the surgical wards and intensive care units, in order to identify sources of outbreaks.
耐甲氧西林金黄色葡萄球菌引起的医院感染构成了重大的流行病学问题。确定一次暴发需要使用快速且高度有鉴别力的流行病学方法来确定参与此类暴发的流行菌株。
开展了一项基于实验室的耐甲氧西林金黄色葡萄球菌描述性监测研究。2001年1月至12月期间，在伊洛林大学教学医院对147株从临床标本中分离出的金黄色葡萄球菌进行了甲氧西林耐药性筛查。对回收的51株（34.7%）耐甲氧西林菌株，采用其质粒DNA的Eco R1限制性酶切分析进行了流行病学特征分析。
45株（88.2%）耐甲氧西林金黄色葡萄球菌分离株与感染相关，6株（11.8%）为定植菌株；分别有36株（70.6%）和15株（29.4%）是医院获得性和社区获得性的。皮肤和软组织是36例（70.6%）感染的部位，外科、急诊和重症监护病房占33株（64.7%）分离株。所有分离株对两种以上抗生素耐药，但对万古霉素敏感。42株（82.4%）分离株含有质粒，其中9株（21.4%）含有不止一个质粒。质粒DNA的限制性酶切分析（REAP）将分离株分为9种Eco R1图谱型，图谱型2占病房所有医院感染的41.7%，这意味着它是地方流行株。其余医院感染图谱型出现频率较低，表明它们是源自医院外的散发菌株。社区菌株显示出多样的酶切模式，表明它们来自不同的克隆。
耐甲氧西林金黄色葡萄球菌的传播可以通过加强抗生素的合理使用、洗手以及对耐甲氧西林金黄色葡萄球菌的实验室监测来控制，特别是在外科病房和重症监护病房，以便确定暴发的源头。
