PFGE, Lior serotype, and antimicrobial resistance patterns among Campylobacter jejuni isolated from travelers and US military personnel with acute diarrhea in Thailand, 1998-2003

Abstract

Background: Campylobacter jejuni is a major cause of gastroenteritis worldwide. In Thailand, several strains of C. jejuni have been isolated and identified as major diarrheal pathogens among adult travelers. To study the epidemiology of C. jejuni in adult travelers and U.S. military personnel with acute diarrhea in Thailand from 1998-2003, strains of C. jejuni were isolated and phenotypically identified, serotyped, tested for antimicrobial susceptibility, and characterized using pulsed-field gel electrophoresis (PFGE).

Results: A total of 312 C. jejuni isolates were obtained from travelers (n = 46) and U.S. military personnel (n = 266) in Thailand who were experiencing acute diarrhea. Nalidixic acid and ciprofloxacin resistance was observed in 94.9% and 93.0% of the isolates, respectively. From 2001-2003, resistance to tetracycline (81.9%), trimethoprim-sulfamethoxazole (57.9%), ampicillin (28.9%), kanamycin (5.9%), sulfisoxazole (3.9%), neomycin (2.0%), and streptomycin (0.7%) was observed. Combined PFGE analysis showed considerable genetic diversity among the C. jejuni isolates; however, four PFGE clusters included isolates from the major Lior serotypes (HL: 36, HL: 11, HL: 5, and HL: 28). The PFGE analysis linked individual C. jejuni clones that were obtained at U.S. military exercises with specific antimicrobial resistance patterns.

Conclusions: In summary, most human C. jejuni isolates from Thailand were multi-resistant to quinolones and tetracycline. PFGE detected spatial and temporal C. jejuni clonality responsible for the common sources of Campylobacter gastroenteritis.

Figure 1

Dendrogram and Lior serotype of 312 C. jejuni isolates from travelers' diarrhea in Thailand (1998-2003). PFGE cluster analysis of a SmaI/KpnI restriction enzyme digest of genomic DNA from 312 C. jejuni isolates analyzed at an 80% similarity cut off, resulting in 62 genotypes distributed between Lior serotypes.

Figure 2

Dendrogram of C. jejuni isolates with Lior serotypes and antimicrobial resistance from Bumrungrad Hospital (2001-2002). Dendrogram A: PFGE cluster analysis of a SmaI/KpnI restriction enzyme digest of genomic DNA from 46 C. jejuni isolates with marked clonal heterogeneity, unrelated antimicrobial resistance patterns, and 25 untypable isolates from this study site. R, resistance; I, intermediate susceptibility; S, susceptible; ND, not tested.

Figure 3

Dendrogram of 54 C. jejuni isolates with Lior serotypes and antimicrobial resistance from Phitsanulok 2001. Dendrogram B: PFGE cluster analysis of a SmaI/KpnI restriction enzyme digest of genomic DNA from 54 C. jejuni isolates from the Cobra Gold exercises (Phitsanulok, 2001) with evidence of clonality due to similarity in the PFGE patterns, Lior serotype(s) and related specific antimicrobial susceptibility patterns (genotypes B1 and B3a). R, resistance; I, intermediate susceptibility; S, susceptible.

Figure 4

Dendrogram of 15 C. jejuni isolates with Lior serotypes and antimicrobial resistance from Sakaew 2002. Dendrogram C: PFGE cluster analysis of a SmaI/KpnI restriction enzyme digest of genomic DNA of 15 C. jejuni isolates from the Cobra Gold exercises (Sakaew, 2002) with evidence of clonality due to similarity in the PFGE patterns (>99.2%), identical Lior serotype (HL:36) and a specific antimicrobial susceptibility pattern (genotype C1 with ampicillin resistance). R, resistance; S, susceptible.

Figure 5

Dendrogram of 23 C. jejuni isolates with Lior serotypes and antimicrobial resistance from Pranburi 2003. Dendrogram D: PFGE cluster analysis of a SmaI/KpnI restriction enzyme digest of genomic DNA of 23 C. jejuni isolates from the Cobra Gold exercises (Pranburi, 2003) with evidence of clonality due to similarity in the PFGE patterns (100%), identical Lior serotype (HL: 4) and specific antimicrobial susceptibility patterns (genotype D1 with additional kanamycin resistance). R, resistance; I, intermediate susceptibility; S, susceptible.