Antimicrobial susceptibility and molecular detection of chloramphenicol and florfenicol resistance among Escherichia coli isolates from diseased chickens

Abstract

Seventy Escherichia coli isolates recovered from diseased chickens diagnosed with colibacillosis in Henan Province, China, between 2004 and 2005 were characterized for antimicrobial susceptibility profiles via a broth doubling dilution method. Overall, the isolates displayed resistance to trimethoprim-sulfamethoxazole (100%), oxytetracycline (100%), ampicillin (83%), enrofloxacin (83%), and ciprofloxacin (81%), respectively. Among the phenicols, resistance was approximately 79% and 29% for chloramphenicol and florfenicol, respectively. Molecular detection revealed that the incidence rates of the floR, cmlA, cat1, cat2 and cat3 were 29, 31, 16, 13, and 0%, respectively. Additionally, 10% of the isolates were positive for both floR and cmlA. As these antimicrobial agents may potentially induce cross-resistance between animal and human bacterial pathogens, their prudent use in veterinary medicine is highly recommended.

Inter- and Intraspecies Plasmid-Mediated Transfer of Florfenicol Resistance in Enterobacteriaceae Isolates from Swine

“…North American and European E. coli strains carrying the floR gene from animal origin have been reported to have MICs for florfenicol of 16 to Ն256 mg/liter and of Ն128 mg/liter, respectively (15). However, MIC values for florfenicol of isolates from South Korea (this study) and E. coli isolates from China were substantially less than those described earlier (6,11,15). This indicates that the MIC for florfenicol could vary geographically, so a comparative study of the florfenicol resistance gene from different geographical regions might help elucidate its mechanism.…”

“…In South Korea, it was initially approved for the treatment of bovine and porcine respiratory disease in 1999 (10,16). Recent reports have shown increasing use of florfenicol in the treatment of target respiratory pathogens as well as in Escherichia coli infection in bovine, porcine, and poultry production (4,6,11,18). This may have lead to the emergence and spread of florfenicol resistance in a wide range of gram-negative and gram-positive bacteria (5,8,15,17,18).…”

Relationships between Mutant Prevention Concentrations and Mutation Frequencies against Enrofloxacin for Avian Pathogenic <i>Escherichia coli</i> Isolates

“…Similarly, Li et al [11] reported that the isolation frequency of O2 strains was 32.4% in the 1990s and 16. [8][9][10][11][12][13][14][15][16][17][18][19].6% in the 2000s in China. These data and our results showing that O2 strains have low MPC values, low mutation frequencies and difficulty in acquiring parC mutations suggest that the population of O2 strains has been decreased through the use of fluoroquinolones in the treatment of avian colibacillosis.…”

“…Treatment of colibacillosis primarily involves the use of approved antimicrobials such as β-lactams, aminoglycosides, tetracyclines, phenicols, antifolates such as sulfonamide and trimethoprim and fluoroquinolones. However, a high proportion of APEC strains have become resistant to these antimicrobial agents [13,19,22]. In Japan, resistance to ampicillin has been observed most frequently (77.1%), followed by resistance to oxytetracycline (75.9%), kanamycin (36.1%), fradiomycin (33.7%), trimethoprim (25.3%) and enrofloxacin (21.7%) [17].…”

Antibiotic Resistance Patterns in Faecal E. coli: A Longitudinal Cohort-Control Study of Hospitalized Horses

“…However florfenicol resistance has been documented in E. coli of animal origin (Singer et al, 2004) and it has been shown that floR genetic determinants and others (i.e. cmlA, cat1, cat2) were also largely related to florfenicol resistance (Li et al, 2007). Others have shown that floR mediated resistance to chloramphenicol and florfenicol is plasmid mediated and also carries resistance to other genes (Blickwede et al, 2007;Kehrenberg et al, 2008).…”