Atypical campylobacters associated with gastroenteritis.

Area of Science:

• Microbiology
• Infectious Diseases
• Bacteriology

Background:

• Campylobacter species are significant causes of bacterial gastroenteritis worldwide.
• Non-jejuni, non-coli, non-laridis Campylobacter species are less understood but can cause human infections.
• Accurate identification of Campylobacter strains is crucial for epidemiological studies and patient management.

Purpose of the Study:

• To characterize and identify nine non-jejuni, non-coli, non-laridis Campylobacter strains isolated from patients with acute diarrhea.
• To differentiate these strains from known Campylobacter species using phenotypic and genotypic methods.
• To investigate the potential for novel Campylobacter species or distinct strains within the genus.

Main Methods:

• Isolation of Campylobacter strains from patient samples.
• Phenotypic characterization using conventional microbiological tests (e.g., hippurate hydrolysis, nitrate reduction, catalase production, antibiotic resistance).
• Genotypic identification using DNA-DNA dot blotting for relatedness to known Campylobacter type strains.

Main Results:

• Three strains were phenotypically and genotypically similar to Campylobacter jejuni.
• Two strains exhibited weak or negative catalase activity and were hippurate negative.
• Three strains showed characteristics consistent with Campylobacter cinaedi.
• One unique strain, isolated from an HIV-positive individual, displayed distinct growth and biochemical properties, differing from all reference strains.

Conclusions:

• The study identified diverse Campylobacter strains beyond the common species, highlighting the complexity of the Campylobacter genus.
• Some strains showed close relation to C. jejuni, while others resembled C. cinaedi.
• A novel Campylobacter strain with unique characteristics was identified, warranting further investigation and potentially classification as a new species.
• These findings underscore the importance of comprehensive identification methods for Campylobacter to fully understand their role in human health.