Vaz-Moreira Ivone, Varela Ana Rita, Pereira Thamiris V, Fochat Romário C, Manaia Célia M
CBQF-Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto , Porto, Portugal .
Microb Drug Resist. 2016 Mar;22(2):155-63. doi: 10.1089/mdr.2015.0118. Epub 2015 Oct 15.
This study is aimed to assess if hospital effluents represent an important supplier of multidrug-resistant (MDR) Gram-negative bacteria that, being discharged in the municipal collector, may be disseminated in the environment and bypassed in water quality control systems. From a set of 101 non-Escherichia coli Gram-negative bacteria with reduced susceptibility to quinolones, was selected a group of isolates comprised by those with the highest indices of MDR (defined as nonsusceptibility to at least one agent in six or more antimicrobial categories, MDR ≥6) or resistance to meropenem or ceftazidime (n = 25). The isolates were identified and characterized for antibiotic resistance phenotype, plasmid-mediated quinolone resistance (PMQR) genes, and other genetic elements and conjugative capacity. The isolates with highest MDR indices were mainly from hospital effluent and comprised ubiquitous bacterial groups of the class Gammaproteobacteria, of the genera Aeromonas, Acinetobacter, Citrobacter, Enterobacter, Klebsiella, and Pseudomonas, and of the class Flavobacteriia, of the genera Chryseobacterium and Myroides. In this group of 25 strains, 19 identified as Gammaproteobacteria harbored at least one PMQR gene (aac(6')-Ib-cr, qnrB, qnrS, or oqxAB) or a class 1 integron gene cassette encoding aminoglycoside, sulfonamide, or carbapenem resistance. Most of the E. coli J53 transconjugants with acquired antibiotic resistance resulted from conjugation with Enterobacteriaceae. These transconjugants demonstrated acquired resistance to a maximum of five classes of antibiotics, one or more PMQR genes and/or a class 1 integron gene cassette. This study shows that ubiquitous bacteria, other than those monitored in water quality controls, are important vectors of antibiotic resistance and can be disseminated from hospital effluent to aquatic environments. This information is relevant to support management options aiming at the control of this public health problem.
本研究旨在评估医院污水是否是多重耐药（MDR）革兰氏阴性菌的重要来源，这些细菌排放到城市污水收集系统中后，可能会在环境中传播，并绕过水质控制系统。从一组对喹诺酮类药物敏感性降低的101株非大肠杆菌革兰氏阴性菌中，选取了一组分离株，这些分离株具有最高的多重耐药指数（定义为对六种或更多抗菌类别中的至少一种药物不敏感，MDR≥6）或对美罗培南或头孢他啶耐药（n = 25）。对这些分离株进行了鉴定，并对其抗生素耐药表型、质粒介导的喹诺酮耐药（PMQR）基因、其他遗传元件和接合能力进行了表征。多重耐药指数最高的分离株主要来自医院污水，包括γ-变形菌纲中普遍存在的细菌群，如气单胞菌属、不动杆菌属、柠檬酸杆菌属、肠杆菌属、克雷伯菌属和假单胞菌属，以及黄杆菌纲中的金黄杆菌属和Myroides属。在这25株菌株中，19株被鉴定为γ-变形菌纲，携带至少一种PMQR基因（aac(6')-Ib-cr、qnrB、qnrS或oqxAB）或编码氨基糖苷、磺胺或碳青霉烯耐药性的1类整合子基因盒。大多数获得性抗生素耐药的大肠杆菌J53转接合子是与肠杆菌科细菌接合产生的。这些转接合子对最多五类抗生素、一种或多种PMQR基因和/或1类整合子基因盒表现出获得性耐药。本研究表明，除了水质控制中监测的细菌外，普遍存在的细菌是抗生素耐药性的重要载体，可从医院污水传播到水生环境。这一信息对于支持旨在控制这一公共卫生问题的管理方案具有重要意义。
