[Evaluation of genotypic and phenotypic methods for the differentiation of Campylobacter jejuni and Campylobacter coli clinical isolates from Poland. I. Biotyping, resistance pattern, plasmid analysis, restriction enzyme analysis of plasmid].

A total of 128 clinical isolates of C. jejuni and 17 clinical isolates of C. coli were characterized by their plasmid profiles, susceptibility to six antimicrobial agents and the Lior biotypes. We also analyzed seven isolates from three C. jejuni family outbreaks and three isolates from one C. coli family outbreak. Plasmids were found in 47 C. jejuni (36.7%) and 3 C. coli (17.6%) isolates. The sizes of plasmids detected ranged from about 3.3 to 89 kb. The majority of Campylobacter isolates (n = 33) had a single plasmid, 11 and three isolates of C. jejuni had two and three plasmids, respectively. The most frequently isolated plasmids ranged from 37 to 48 kb (n = 26). The single plasmids were discriminated on the basis of their BglII patterns. The majority of 45 kb (n = 12) plasmids had the indistinguishable pattern. The significant association (p < 0.0001) between tetracycline resistance and plasmid carriage was observed. All except one (hippuric-negative C. jejuni isolate) C jejuni isolates were biotyped using the Lior biotyping scheme. Three biotypes of C. jejuni and 2 biotypes of C. coli were identified among the isolates; 60.2% were C. jejuni I, 38.2% C. jejuni II, 0.8% C. jejuni III, 70.6% C. coli I and 29.4% C. coli II. In this study the least discriminatory subtyping method was biotyping (D = 0.505). C. jejuni isolates were the most resistant to ciprofloxacin and nalidixic acid (64.1%) followed by tetracycline (23.4%) and ampicillin (13.3%). Fifteen isolates of C. coli were resistant to ciprofloxacin and nalidixic acid (88.2%), three to ampicillin and one to tetracycline. All of the C. jejuni and C. coli isolates were sensitive to erythromycin and gentamicin. Resistance to ciprofloxacin was found in all quinolone-resistant isolates. Thirty seven isolates (28.9%) were susceptible to all antimicrobial agents tested. Six C. jejuni (4.7%) and one C. coli isolates showed resistance to more than three drugs. The fact that the most of the C. jejuni and C. coli isolates tested were biotype I and possessed no plasmid limited the usefulness of biotyping and plasmid analysis as epidemiological markers. The results of susceptibility testing of C. jejuni and C. coli isolates showed high percentage of resistance to quinolones.