Oduyebo O O, Falayi O M, Oshun P, Ettu A O
Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Idi-Araba, Lagos, Nigeria.
Niger Postgrad Med J. 2015 Oct-Dec;22(4):223-7. doi: 10.4103/1117-1936.173973.
Carbapenemase production among clinical isolates of Enterobacteriaceae has been widely reported with prevalence rates ranging from between 2.8% and 53.6%. The aim of this study was to assess the prevalence of carbapenemase production among clinical isolates of Enterobacteriaceae from a Tertiary Hospital in Lagos, Nigeria, and to characterize the type of carbapenemase produced.
Carbapenemase production was detected phenotypically using a commercially available combination disc test (Rosco Diagnostica carbapenemase detection Neo-Sensitab) containing inhibitors to the various carbapenemase classes. The Neo-Sensitabs were used for Enterobacteriaceae isolates that were resistant after the initial antibiotic susceptibility testing with meropenem (10 μg).
A total of 177 Enterobacteriaceae isolates were investigated and 27 (15.2%) were carbapenem-resistant. From the 27 carbapenem non-susceptible isolates, 22 (12.4%) were carbapenemase producers while 5 (2.8%) exhibited carbapenem resistance due to extended spectrum beta-lactamase production. Of the 22 isolates that were positive for carbapenemase production, 15 (8.5%) were metallo beta-lactamase (MBL) producers, 6 (3.4%) produced oxacillinase-48 while 1 (0.5%) produced both MBL and Klebsiella pneumoniae carbapenemase. Hence, the overall prevalence of carbapenemase-producing Enterobacteriaceae in this study was 12.4%.
Carbapenemase-producing Enterobacteriaceae was indeed prevalent in our institution. The combination disc test was a cost effective and suitable method for the initial detection of carbapenemase-producing Enterobacteriaceae within the clinical setting especially when molecular detection methods are not available.
肠杆菌科临床分离株中产碳青霉烯酶的情况已有广泛报道，流行率在2.8%至53.6%之间。本研究的目的是评估尼日利亚拉各斯一家三级医院肠杆菌科临床分离株中产碳青霉烯酶的流行情况，并鉴定所产生的碳青霉烯酶类型。
使用市售的组合纸片试验（罗斯科诊断公司碳青霉烯酶检测新型药敏纸片）通过表型检测碳青霉烯酶的产生，该纸片含有针对各种碳青霉烯酶类别的抑制剂。新型药敏纸片用于对美罗培南（10μg）进行初始药敏试验后耐药的肠杆菌科分离株。
共调查了177株肠杆菌科分离株，其中27株（15.2%）对碳青霉烯类耐药。在这27株对碳青霉烯不敏感的分离株中，22株（12.4%）是碳青霉烯酶生产者，而5株（2.8%）由于产超广谱β-内酰胺酶而表现出对碳青霉烯类耐药。在22株碳青霉烯酶产生阳性的分离株中，15株（8.5%）是金属β-内酰胺酶（MBL）生产者，6株（3.4%）产生奥克西西林酶-48，1株（0.5%）同时产生MBL和肺炎克雷伯菌碳青霉烯酶。因此，本研究中产碳青霉烯酶肠杆菌科的总体流行率为12.4%。
产碳青霉烯酶肠杆菌科在我们机构中确实很普遍。组合纸片试验是在临床环境中初步检测产碳青霉烯酶肠杆菌科的一种经济有效的合适方法，尤其是在无法使用分子检测方法时。
