Begum Nurjahan, Shamsuzzaman S M
Department of Microbiology, Dhaka Medical College, Dhaka, Bangladesh.
Tzu Chi Med J. 2016 Jul-Sep;28(3):94-98. doi: 10.1016/j.tcmj.2016.04.005. Epub 2016 May 27.
A growing incidence of pathogens producing carbapenemases has been observed in many countries including Bangladesh. The present study was carried out to determine the presence of carbapenemase producers among uropathogens.
A total of 138 Gram-negative uropathogens were isolated and identified by conventional methods and were screened for carbapenemase production using imipenem discs. Phenotypic identification of carbapenemase production was done by the double disc synergy test, combined disc assay, and modified Hodge test. The minimum inhibitory concentration of imipenem was determined by the agar dilution method. Genes encoding NDM-1, IMP, VIM, KPC and OXA-48/OXA-181 were identified by polymerase chain reaction.
Twenty (14.49%) imipenem resistant strains were detected among 138 Gram-negative uro-pathogens. The most common isolates were and spp. Among 20 imipenem resistant strains, 16 (80%) carbapenemase producers were detected by polymerase chain reaction, 13 (65%) by double disc synergy, 15 (75%) by combined disc assay, and seven (35%) by modified Hodge test. The NDM-1 gene was most prevalent (55%), followed by OXA-48/OXA-181, KPC (20%), VIM (15%), and IMP (10%). More than one carbapenemase gene was present in nine (45%) of the isolates. The minimum inhibitory concentration of imipenem of the carbapenemase producers ranged from ≥128 μg/mL to 4 μg/mL. Overall, carbapenemase encoding genes were detected in 11.6% (16/138) of the studied Gram-negative uropathogens. All (100%) of the carbapenemase-producing organisms were resistant to all tested antibiotics apart from colistin.
The study shows a significant rate of urinary isolates were carbapenemase producers, including a high prevalence of NDM-1, in Bangladesh.
在包括孟加拉国在内的许多国家，产碳青霉烯酶病原体的发病率呈上升趋势。本研究旨在确定尿路病原体中产碳青霉烯酶菌株的存在情况。
共分离出138株革兰氏阴性尿路病原体，采用常规方法进行鉴定，并使用亚胺培南纸片筛选碳青霉烯酶的产生情况。通过双纸片协同试验、联合纸片试验和改良Hodge试验对碳青霉烯酶产生进行表型鉴定。采用琼脂稀释法测定亚胺培南的最低抑菌浓度。通过聚合酶链反应鉴定编码NDM-1、IMP、VIM、KPC和OXA-48/OXA-181的基因。
在138株革兰氏阴性尿路病原体中检测到20株（14.49%）对亚胺培南耐药的菌株。最常见的分离菌是 和 属。在20株对亚胺培南耐药的菌株中，通过聚合酶链反应检测到16株（80%）产碳青霉烯酶菌株，通过双纸片协同试验检测到13株（65%），通过联合纸片试验检测到15株（75%），通过改良Hodge试验检测到7株（35%）。NDM-1基因最为常见（55%），其次是OXA-48/OXA-181、KPC（20%）、VIM（15%）和IMP（10%）。9株（45%）分离菌中存在不止一种碳青霉烯酶基因。产碳青霉烯酶菌株的亚胺培南最低抑菌浓度范围为≥128μg/mL至4μg/mL。总体而言，在所研究的革兰氏阴性尿路病原体中，11.6%（16/138）检测到碳青霉烯酶编码基因。除黏菌素外，所有（100%）产碳青霉烯酶的菌株对所有测试抗生素均耐药。
该研究表明，在孟加拉国，尿路分离株中产碳青霉烯酶菌株的比例较高，其中NDM-1的流行率很高。
