Microbiology Laboratory, Maputo Central Hospital, Maputo, Mozambique.
High Institute of Health Sciences (ISCISA), Maputo, Mozambique.
BMC Infect Dis. 2018 May 30;18(1):244. doi: 10.1186/s12879-018-3154-1.
In recent years, the world has seen a surge in Enterobacteriaceae resistant to broad-spectrum beta-lactam antibiotics due to the production of extended-spectrum beta-lactamases (ESBLs) or plasmid-mediated AmpC (pAmpC) enzymes. Data on the epidemiology of cephalosporin-resistant Enterobacteriaceae in Sub-Saharan Africa are still limited.
Two hundred seventy-five non-repetitive stool samples were collected from Mozambican university students of both sexes. Samples were cultured on MacConkey agar with and without ceftriaxone (1 mg/L) for selection of third-generation cephalosporin-resistant isolates, which were subjected to antimicrobial susceptibility testing by disc diffusion, characterization of resistance genes by PCR and ERIC-PCR analysis for strain clonality.
Among the 275 students, 55 (20%) carried a total of 56 E. coli (n = 35) and Klebsiella spp. (n = 21) isolates resistant to ceftriaxone and phenotypically positive for ESBL- and/or pAmpC-production. Forty-three percent of the isolates (24/56) contained only ESBL genes, 11% (6/56) only pAmpC genes, and 36% (20/56) both ESBL and pAmpC genes. The remaining six isolates were negative for the CTX-M/pAmpC genes included in the test panel. E. coli and Klebsiella spp. combined demonstrated 70% resistance to tetracycline and co-trimoxazole, 63% to ceftazidime and 34% to ciprofloxacin. In total, 89% of ESBL/pAmpC-positive isolates were defined as multi-resistant by being resistant to three or more antibiotic classes. ERIC-PCR fingerprinting demonstrated low similarity among isolates. None of the participants reported recent hospitalization and just 12.5% had taken antibiotics 3 months prior to the study.
This study demonstrated 20% colonization with multi-resistant E. coli and Klebsiella spp. among Mozambican students with a diversity of ESBL and pAmpC genes. Colonization was not related to prior hospitalization or antimicrobial consumption.
近年来，由于广谱β-内酰胺酶（ESBLs）或质粒介导的 AmpC（pAmpC）酶的产生，世界范围内对广谱β-内酰胺抗生素耐药的肠杆菌科数量激增。撒哈拉以南非洲头孢菌素耐药肠杆菌科的流行病学数据仍然有限。
从莫桑比克男女大学生中采集了 275 份非重复粪便样本。将样本接种于含有和不含有头孢曲松（1mg/L）的 MacConkey 琼脂上，以选择第三代头孢菌素耐药分离株，采用纸片扩散法进行抗菌药物敏感性试验，PCR 法鉴定耐药基因，ERIC-PCR 分析菌株的克隆性。
在 275 名学生中，有 55 名（20%）共携带 56 株大肠埃希菌（n=35）和克雷伯菌属（n=21）对头孢曲松耐药且表型产 ESBL 和/或 pAmpC 的分离株。43%（24/56）的分离株仅含有 ESBL 基因，11%（6/56）仅含有 pAmpC 基因，36%（20/56）同时含有 ESBL 和 pAmpC 基因。其余 6 株分离株对试验组中包含的 CTX-M/pAmpC 基因均为阴性。大肠埃希菌和克雷伯菌属联合对四环素和复方磺胺甲噁唑的耐药率为 70%，对头孢他啶和环丙沙星的耐药率分别为 63%和 34%。总的来说，89%的 ESBL/pAmpC 阳性分离株因对三种或三种以上抗生素类别耐药而被定义为多耐药。ERIC-PCR 指纹图谱显示分离株之间的相似度较低。没有参与者报告最近住院，只有 12.5%的人在研究前 3 个月内服用过抗生素。
本研究表明，莫桑比克大学生中存在 20%携带多种耐药大肠埃希菌和克雷伯菌属的定植，且具有多种 ESBL 和 pAmpC 基因。定植与既往住院或抗菌药物使用无关。
