ABSTRACT
The aim of this study was to determine the prevalence and antibiotic susceptibility of Escherichia coli from retail raw chickens in different provinces of China.A total of 1 152 whole chicken samples were collected and screened for the prevalence of E.coli,and then the E.coli isolates were further tested for the antimicrobial susceptibility using agar dilution method.Results showed that the overall positive rate for E.coli in retail chickens was 65.97％ (760/1 152);resistance was most common to nalidixic acid (66.84％),followed by amoxicillin-clavulanic acid (66.05％),tetracycline (65.00％),trimethoprim-sulfamethoxazole (63.16 ％),ampicillin (60.66 ％),amoxicillin (51.32 ％),streptomycin (50.39 ％),chloramphenicol (48.32 ％),kanamycin (38.29 ％),gentamicin (26.31％),ciprofloxacin (25.79 ％) and cefoxitin (21.05 ％).The last were gatifloxacin,cefoperazone and amikacin (each ＜20％).Overall,70.53％ of the isolates were resistant to at least three antimicrobials.A large proportion of multidrug resistant isolates were resistant to 8 kinds of antimicrobials (10.26 ％).No strain was resistant to 15 kinds of antimicrobials.Furthermore,isolates recovered from different regions exhibited different resistance levels to most antimicrobials.Our findings indicate that retail chicken in China was commonly contaminated with E.coli,and many E.coli strains exhibited multiple drug resistance.Presence of multiple drug E.coli in raw chickens may pose a potential threat to human health.
ABSTRACT
<p><b>OBJECTIVE</b>Salmonella isolates recovered from retail meats that were collected in supermarkets and free markets in Xi'an and Yangling areas of Shaanxi province were studied to determine antibiotic susceptibility.</p><p><b>METHOD</b>Antimicrobial susceptibility to 14 antibiotics of 193 salmonella isolates were determined by using agar dilution method, which was recommended by National Committee of Clinical Laboratory Standard (NCCLS), and E.coli ATCC25922 and E.faecalis ATCC29212 as standard control strains.</p><p><b>RESULTS</b>The 44.6% of the salmonella isolates were resistant to sulfamethoxazole, followed by resistance to kanamycin (40.9%), tetracycline (37.8%), amoxicillin (26.9%), ampicillin (25.4%), gentamicin (23.3%) and chloramphenicol (21.8%). Some isolates also showed resistance to fluoroquinolones, the rates for ciprofloxacin, enrofloxacin, levofloxacin and gatifloxacin were 22.3%, 21.8%, 20.8% and 21.2%, respectively. 55 isolates (28.5%) were multidrug resistant (MDR) strains, 28 of 193 isolates (14.5%) could resist at least 13 antibiotics, 24 isolates (12.4%) were resistant to from 4 to 12 antibiotics.</p><p><b>CONCLUSION</b>Salmonella isolates recovered from retail meats in Xi'an district of Shaanxi province were seriously resistant to antimicrobials commonly used as human and veterinary medicine.</p>