Resistance of Campylobacter jejuni Isolated from Layer Farms in Northern Jordan Using Microbroth Dilution and Disc Diffusion Techniques

Prevalence, antibiotic resistance and genotypes of Campylobacter jejuni and Campylobacter coli isolated from chickens in Irbid governorate, Jordan

Campylobacter is the world's leading cause of bacterial gastroenteritis, causing nearly 9 million cases of food poisoning in Europe every year. Poultry is considered the main source of Campylobacter infection to humans. The objectives of the study were to determine occurrence of C. jejuni and C. coli in chickens, the antimicrobial resistance, genotypes, and relatedness of the isolates. A total of 177 chicken samples obtained from informal butcher shops (fresh), formal poultry slaughterhouses (refrigerated) and retail market (frozen) were analyzed. Isolation of Campylobacter spp. was conducted according to the ISO 10272-2006 method. Multiplex PCR was used for confirmation and identification of the isolates. The disk diffusion method was used to determine the antimicrobial resistance of the isolates and multilocus sequence typing was used for genotyping. The proportion of samples with Campylobacter spp. was 31.6% among all chicken samples (fresh and refrigerated 47.5%, frozen 0%) C. coli was isolated from 42.4% of chicken samples obtained from butcher shops and from 18.6% of samples obtained in formal slaughterhouses. C. jejuni was isolated from 17.0% of samples obtained in butcher shops and formal slaughterhouses. Campylobacter spp. was not isolated in frozen chicken samples. All tested isolates showed resistance toward ciprofloxacin and susceptibility toward imipenem and all of the isolates were multidrug resistant toward 5 or more antimicrobials. Three sequence types were identified among 10 C. coli isolates and seven sequence types were identified among 10 C. jejuni isolates. Among sequence types, chicken isolates shared similarities of both phenotypic and genetic levels.

Antimicrobial Susceptibility and Virulence Surveillance of Campylobacter spp. Isolated From Patients in Two Tertiary Medical Centers in Taiwan

Campylobacter spp. may cause fever, vomiting, and diarrhea in humans. Antibiotic treatment is suggested for patients with severe campylobacteriosis. However, the interpretative criteria for antibiotic susceptibility are inconsistent between Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing guidelines. The aim of the study is to investigate the antibiotic susceptibility and prevalence of cytolethal distending toxin genes and to evaluate antibiotic susceptibility testing methods in the clinical laboratories of two tertiary medical centers in Taiwan. In total, 236 bacterial isolates were collected between 2001 and 2014. The disk diffusion and E-test methods were used to evaluate the antibiotic susceptibility, and broth dilution results were used as a reference. The virulence genes cdtA, cdtB, cdtC, and ceuE were detected through polymerase chain reaction. The antimicrobial sensitivity rates for erythromycin, ciprofloxacin, and tetracycline using the broth dilution assay were 80.4, 5.4, and 3.4%, respectively. No significant differences were observed in the antibiotic susceptibility of the isolates obtained from southern and northern Taiwan. However, some differences were observed between species. The susceptibility test for erythromycin (disk diffusion) showed that the isolates with small inhibition zone diameters were all resistant, and five isolates (4.0%) with large IZDs were non-sensitive. The error rate of the disk diffusion method according to the CLSI M45-A3 guideline was 5.4% (8/148). The incompatibility rates between the E-test and broth dilution methods for erythromycin, ciprofloxacin, and tetracycline were 8.0, 5.3, and 1.3%, respectively. The positive rates of the genes cdtA and cdtC were considerably higher in Campylobacter jejuni than in C. coli. Erythromycin is recommended as the first choice of treatment for campylobacteriosis. The disk diffusion method is suitable for prescreening Campylobacter susceptibility by using the CLSI M45-A2 and EUCAST criteria (low error rate of 3.4%). If antibiotic treatment fails or IZDs are between 6 and 20 mm, minimum inhibitory concentration testing by using the E-test method is highly recommended because the results of the E-test and broth dilution methods exhibit high agreement. The error rate of disk diffusion method using CLSI M45-A3 criteria is only slightly higher than B, which is also a suitable criteria.

Virulence and Antimicrobial Resistance in Campylobacter spp. from a Peruvian Pediatric Cohort

The presence of virulence factors (VFs) and mechanisms of quinolones and macrolide resistance was analyzed in Campylobacter spp. from a pediatric cohort study in Lima. In 149 isolates (39 Campylobacter jejuni and 24 Campylobacter coli from diarrheic cases; 57 C. jejuni and 29 C. coli from controls), the presence of the cdtABC and cadF genes and iam marker was established. Nalidixic acid, ciprofloxacin, erythromycin, and azithromycin susceptibilities were established in 115 isolates and tetracycline-susceptibility was established in 100 isolates. The presence of mutations in the gyrA, parC, and 23S rRNA genes was determined. The cadF gene and all genes from the cdtABC operon were significantly more frequent among C. jejuni (P < 0.0001); the iam marker was more frequent in C. coli (P < 0.0001). No differences were observed in VFs between cases and controls. Almost all isolates were tetracycline-resistant; nalidixic acid and ciprofloxacin resistance reached levels of 90.4% and 88.7%, respectively. Resistance to macrolides was 13% (C. jejuni 4.3%; C. coli 26.1%). Resistance to ciprofloxacin was related to GyrA Thr86 substitutions, while 13 of 15 macrolide-resistant isolates possessed a 23S rRNA mutation (A2075G). Differences in the presence of VFs and alarming levels of resistance to tested antimicrobial agents were observed among C. jejuni and C. coli.