Idowu Olusolabomi J, Onipede Anthony O, Orimolade Ayodele E, Akinyoola Lawrence A, Babalola Gbolahan O
Department of Microbiology, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria.
J Glob Infect Dis. 2011 Jul;3(3):211-5. doi: 10.4103/0974-777X.83524.
Extended-spectrum beta-lactamase (ESBL)-producing Gram-negative bacteria are emerging and impacting significantly on the management of patients and hospital costs. Besides, they are not being routinely sought after in diagnostic laboratories thus contributing to treatment failure.
Bacterial isolates from wounds of 45 patients were identified using commercial identification kits and antibiotic susceptibility was evaluated by the Bauer-Kirby method. Screening and phenotypic confirmation of ESBL production were done as prescribed by the Clinical and Laboratory Standards Institute. The conjugation experiment was performed by the mating assay in broth between the ESBL producers and E. coli ATCC 25922 as the recipient.
Out of 102 Gram-negative bacteria isolated, 36 were positive for ESBL mainly of the Enterobacteriaceae family (33) and the rest were oxidase-positive bacilli (3). The predominant bacteria were Klebsiella spp. and E. coli. Others were Serratia rubidae, Citrobacter freundii, Morganella morgannii, Proteus spp., Providencia stuartii, and Enterobacter spp. There was a significant association between treatment with third-generation cephalosporins (3GCs) and isolation of ESBLs (P=0.0020). The ESBL producers were multiply resistant and moderately sensitive to colistin. The conjugation experiment showed that the ESBL gene was transferred horizontally and tetracycline, cotrimoxazole, nitrofurantoin, gentamicin, and aztreonam resistance genes were co-transferred. No mortality was recorded but the mean length of stay in the hospital was 82 days.
The development and spread of ESBL among Gram-negative bacteria and possible horizontal transfer calls for concern, especially in view of treatment failure, high treatment cost, and consequent discomfort to patients.
产超广谱β-内酰胺酶（ESBL）的革兰氏阴性菌不断出现，对患者的治疗管理和医院成本产生了重大影响。此外，诊断实验室并未常规检测这些细菌，从而导致治疗失败。
使用商业鉴定试剂盒对45例患者伤口的细菌分离株进行鉴定，并采用鲍尔-柯蒂斯法评估抗生素敏感性。按照临床和实验室标准协会的规定进行ESBL产生的筛选和表型确认。通过肉汤中的接合试验，以ESBL产生菌为供体、大肠杆菌ATCC 25922为受体进行接合实验。
在分离出的102株革兰氏阴性菌中，36株ESBL检测呈阳性，主要为肠杆菌科（33株），其余为氧化酶阳性杆菌（3株）。主要细菌为克雷伯菌属和大肠杆菌。其他还有深红沙雷菌、弗氏柠檬酸杆菌、摩根摩根菌、变形杆菌属、斯氏普罗威登斯菌和肠杆菌属。第三代头孢菌素（3GCs）治疗与ESBL分离之间存在显著关联（P = 0.0020）。产ESBL菌具有多重耐药性，对黏菌素中度敏感。接合实验表明，ESBL基因可水平转移，同时四环素、复方新诺明、呋喃妥因、庆大霉素和氨曲南耐药基因也会共同转移。未记录到死亡病例，但患者平均住院时间为82天。
ESBL在革兰氏阴性菌中的产生和传播以及可能的水平转移令人担忧，尤其是考虑到治疗失败、高治疗成本以及给患者带来的不适。
