Centre for Enteric Diseases, National Institute for Communicable Diseases, Division in the National Health Laboratory Service, Johannesburg.
J Infect Dis. 2013 Nov 1;208 Suppl 1:S39-45. doi: 10.1093/infdis/jit200.
A total of 720 Vibrio cholerae O1 strains were recovered for investigation from an outbreak of cholera in South Africa between November 2008 and April 2009.
Strains were characterized by serotype testing. Antimicrobial susceptibility testing. Genetic diversity of 248 strains was investigated using pulsed-field gel electrophoresis (PFGE) analysis. Extended characterization was performed on 90 strains. Molecular analysis included: polymerase chain reaction (PCR) identification of ctxA and tcpA genes, sequencing the ctxAB gene, and investigation of molecular mechanisms conferring antimicrobial resistance.
The majority of strains were characterized as serotype Ogawa. Strains showed multidrug resistance. Approximately 1.0% of strains displayed extended-spectrum β-lactamase (ESBL) activity. Strains showed very similar PFGE patterns. Ninety strains selected for extended characterization showed the following results: Strains possessed the cholera toxin (CT) and all were PCR positive for the tcpA-El Tor variant. Sequencing of the ctxB gene matched the B-1 allele. Strains harbored the SXT element. Strains that displayed ESBL activity possessed a 140-kilobase-pair plasmid that produced the TEM-63 β-lactamase. Nalidixic acid-resistant strains harbored mutations in GyrA (Ser83-Ile) and ParC (Ser85-Leu).
These data highlight the rapid development of antimicrobial resistance and spread of V. cholerae O1 El Tor variants expressing the classical CT within South Africa.
2008 年 11 月至 2009 年 4 月期间，南非爆发霍乱疫情，共从该疫情中回收了 720 株霍乱弧菌 O1 菌株进行调查。
通过血清型检测对菌株进行鉴定。进行药敏试验。采用脉冲场凝胶电泳（PFGE）分析对 248 株菌株的遗传多样性进行研究。对 90 株菌株进行了扩展特征描述。分子分析包括：PCR 鉴定 ctxA 和 tcpA 基因、ctxAB 基因测序以及研究赋予抗菌药物耐药性的分子机制。
大多数菌株被鉴定为血清型 Ogawa。菌株表现出多重耐药性。大约 1.0%的菌株显示出扩展型β-内酰胺酶（ESBL）活性。菌株显示出非常相似的 PFGE 模式。选择了 90 株进行扩展特征描述的菌株得到以下结果：菌株携带霍乱毒素（CT），并且所有菌株均对 tcpA-El Tor 变体呈 PCR 阳性。ctxB 基因测序与 B-1 等位基因匹配。菌株携带 SXT 元件。表现出 ESBL 活性的菌株拥有一个产生 TEM-63β-内酰胺酶的 140 千碱基对质粒。耐萘啶酸的菌株在 GyrA（Ser83-Ile）和 ParC（Ser85-Leu）中存在突变。
这些数据突出表明，在南非，抗菌药物耐药性迅速发展，以及表达经典 CT 的霍乱弧菌 O1 El Tor 变体的传播。
