Mala Wanida, Kaewkes Wanlop, Tattawasart Unchalee, Wongwajana Suwin, Faksri Kiatichai, Chomvarin Chariya
Southeast Asian J Trop Med Public Health. 2016 Sep;47(5):957-66.
Emergence of multiple drug resistance in Vibrio cholerae has been increasing around the world including Northeast Thailand. In this study, 92 isolates of V. cholerae (50 O1 and 42 non-O1/non-O139 isolates) from clinical and environmental sources in Northeast Thailand were randomly selected and investigated for the presence of SXT element, class 1 integron and antimicrobial resistance genes. Genotypic-phenotypic concordance of antimicrobial resistance was also determined. Using PCR-based assays, 79% of V. cholerae isolates were positive for SXT element, whereas only 1% was positive for class 1 integron. SXT element harbored antimicrobial resistance genes, dfrA1 or dfr18, floR, strB, sul2, and tetA. Overall phenotypic-genotypic concordance of antimicrobial resistance was 78%, with highest and lowest value being for trimethoprim (83%) and chloramphenicol (70%), respectively. Ninety-two percent of V. cholerae O1 strains isolated from clinical sources harbored both dfrA1 (O1-specific trimethoprim resistance gene) and dfr18 (non-O1-specific trimethoprim resistance gene), whereas only 5% of V. cholerae non-O1/non-O139 strains harbored both genes. All V. cholerae O1 isolated from environmental source harbored dfr18 but 48% of V. cholerae non-O1/non-O139 harbored dfrA1. This study indicates that SXT element was the main contributor to the circulation of multiple-drug resistance determinants in V. cholerae strains in Northeast Thailand and that genetic exchange of SXT element can occur in both V. cholerae O1 and non-O1/non-O139 strains from clinical and environmental sources.
包括泰国东北部在内，霍乱弧菌多重耐药性在全球范围内不断增加。在本研究中，从泰国东北部临床和环境来源随机选取了92株霍乱弧菌（50株O1血清型和42株非O1/非O139血清型菌株），检测SXT元件、1类整合子及抗菌药物耐药基因的存在情况，并确定抗菌药物耐药性的基因型-表型一致性。采用基于PCR的检测方法，79%的霍乱弧菌菌株SXT元件呈阳性，而1类整合子阳性率仅为1%。SXT元件携带抗菌药物耐药基因dfrA1或dfr18、floR、strB、sul2和tetA。抗菌药物耐药性的总体基因型-表型一致性为78%，甲氧苄啶（83%）和氯霉素（70%）分别为最高和最低值。从临床来源分离的霍乱弧菌O1菌株中，92%同时携带dfrA1（O1血清型特异性甲氧苄啶耐药基因）和dfr18（非O1血清型特异性甲氧苄啶耐药基因），而霍乱弧菌非O1/非O139菌株中只有5%同时携带这两个基因。从环境来源分离的所有霍乱弧菌O1菌株均携带dfr18，但48%的霍乱弧菌非O1/非O139菌株携带dfrA1。本研究表明，SXT元件是泰国东北部霍乱弧菌菌株中多重耐药决定因素传播的主要原因，且SXT元件的基因交换可发生在临床和环境来源的霍乱弧菌O1和非O1/非O139菌株中。
