Studies on the species and antimicrobial sensitivity of marine bacteria off Zhoushan Archipelago

Abstract

Objective To investigate the species and distribution of marine bacteria off Zhoushan Archipelago of China and to analyze their antimicrobial sensitivity in this sea region.Methods Seawater samples were collected by sterile sampling devices,and then the collected bacteria were enriched,cultured,isolated and single colony was chosen for study.Bacteria identification and drug sensitivity tests were performed by VITEK-AMS,the API microbial identification system and the BIMIC Vision system.Colony counting of the seawater was also performed accordingly.Results Fifty-seven strains were isolated from 46 seawater samples,of which 28 were vibrios (49.1％),19 were enterobacteria (33.3％),8 nonfermenters (14.0％),1 Enterococcus feacium (1.8％) and 1 fungus (1.8％).Drug sensitivity tests indicated that in the more than 20 kinds of antibiotics vibrios,nonfermenters and enterobacteria were generally highly susceptible to Imipenem,Meropenem,Cefepime,Ceftazidime and Levofloxacin (＞ 95％),they could be used as first-choice antibiotics.Rates of susceptibility to Chloramphenicol,Cefotaxime,Tobramycin,Ciprofloxacin,Aztreonam,Ceftriaxone,Cefoperazone,Piperacillin and Tazobactam were within ranges of 80％-94％.They could be used as optional antibiotics.However,the marine bacteria were less susceptible to SMZ,Piperacillin,Cefuroxime,and Ampicillin (＜ 60％),which should be prohibited or used with care.Conclusions This study has helped to establish a basic database of bacterial spectrum and sensitivity of Zhoushan Archipelago.It will provide basic theoretical evidence for early prevention/treatment and selection of antibiotics in those offshore mariners who are accidentally injured and complicated with seawater immersion. Key words: Marine bacteria; Bacteria identification; Antibiotics; Antimicrobial susceptibility test