Oduro-Mensah Daniel, Obeng-Nkrumah Noah, Bonney Evelyn Yayra, Oduro-Mensah Ebenezer, Twum-Danso Kingsley, Osei Yaa Difie, Sackey Sammy Tawiah
Department of Biochemistry, Cell and Molecular Biology, School of Biological Sciences, University of Ghana, Legon, Accra, Ghana.
Department of Applied Chemistry and Biochemistry, University for Development Studies, Navrongo Campus, Navrongo, Ghana.
Ann Clin Microbiol Antimicrob. 2016 May 4;15:29. doi: 10.1186/s12941-016-0144-2.
Antibiotic resistance due to the presence of extended-spectrum beta-lactamases (ESBLs) among Enterobacteriaceae is a worldwide problem. Data from Ghana regarding this resistance mechanism is limited. This study was designed to investigate the presence of TEM-type ESBL genes, their locations and their conjugabilities in clinical isolates of enterobacteria collected from the Korle-Bu Teaching Hospital in Ghana.
Study isolates were characterized with respect to ESBL phenotype, TEM-type ESBL gene detection, location of the ESBL gene(s) and conjugability of the ESBL phenotype using nalidixic acid-resistant Escherichia coli K-12 as recipient. Phenotyping was by Kirby Bauer disk diffusion using cefpodoxime, ceftazidime, cefotaxime and their combinations with clavulanate. Gene detections were by PCR using blaTEM primers.
Overall, 37.96 % of 137 clinical isolates showed ESBL phenotype. The ESBLs occurred mostly in Klebsiella spp. (42.3 %) and then Escherichia coli (34.6 %). The TEM gene was detected in 48.1 % of ESBL-positive isolates and was determined to be plasmid-borne in 24 of 25 blaTEM detections. Overall, 62.7 % of TEM-producing isolates transferred the ESBL phenotype by conjugation.
The results highlight the presence of TEM-type ESBLs in the Korle-Bu Teaching Hospital and show considerable risk of environmental contamination through the urine of infected persons. An inhibition zone chart was generated which indicates the possible presence of complex beta-lactamase types. The data points to the fact that the ESBL-producing bacteria may disseminate this resistance mechanism via conjugation.
肠杆菌科细菌中因存在超广谱β-内酰胺酶（ESBLs）而导致的抗生素耐药性是一个全球性问题。加纳关于这种耐药机制的数据有限。本研究旨在调查从加纳科勒-布教学医院收集的临床分离肠杆菌中TEM型ESBL基因的存在情况、其位置及其接合性。
使用耐萘啶酸的大肠杆菌K-12作为受体，对研究分离株进行ESBL表型、TEM型ESBL基因检测、ESBL基因位置以及ESBL表型接合性的特征分析。表型分析采用头孢泊肟、头孢他啶、头孢噻肟及其与克拉维酸组合的纸片扩散法（Kirby Bauer）。基因检测采用blaTEM引物进行PCR。
总体而言，137株临床分离株中有37.96%表现出ESBL表型。ESBLs大多出现在克雷伯菌属（42.3%），其次是大肠杆菌（34.6%）。在48.1%的ESBL阳性分离株中检测到TEM基因，在25次blaTEM检测中有24次确定其为质粒携带。总体而言，62.7%产生TEM的分离株通过接合转移了ESBL表型。
结果突出了科勒-布教学医院中TEM型ESBLs的存在，并显示出通过感染者尿液造成环境污染的相当大风险。生成了一个抑菌圈图表，表明可能存在复杂的β-内酰胺酶类型。数据表明产生ESBL的细菌可能通过接合传播这种耐药机制。
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