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Distribution of sero-biotypes of Campylobacter jejuni and C. coli isolated from paediatric patients
Insights
Campylobacter jejuni and C. coli infections in children are common in Cape Town. Most isolates were C. jejuni biotype 1, with high resistance to TTC and common serotypes identified, though many remained untyped.
Area of Science:
- Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Campylobacter jejuni and C. coli are leading causes of bacterial gastroenteritis and bacteraemia in children globally.
- Understanding the characteristics of local Campylobacter isolates is crucial for effective diagnosis and treatment strategies.
- Previous studies highlight the need for detailed characterization of Campylobacter strains in different geographical regions.
Purpose of the Study:
- To biotype and serotype Campylobacter jejuni and C. coli isolates from children in Cape Town, South Africa.
- To determine the prevalence of different biotypes and serotypes.
- To assess antimicrobial resistance patterns, specifically to 2,3,5-triphenyltetrazolium chloride (TTC).
Main Methods:
- Collection of 258 Campylobacter isolates from children with gastroenteritis or bacteraemia over one year.
- Biotyping using hippurate hydrolysis, H2S production, and TTC tolerance.
- Serotyping based on soluble, thermostable antigens using passive-haemagglutination.
Main Results:
- 95.4% of isolates were C. jejuni biotype 1, with 3.1% C. coli and 1.5% C. jejuni biotype 2.
- 70% of isolates exhibited resistance to TTC.
- Serotyping identified common serotypes (4, 2, 12, 23/36, 19), but 21% of isolates were non-typable with current antisera.
Conclusions:
- C. jejuni biotype 1 is the predominant type causing pediatric infections in Cape Town.
- High TTC resistance suggests potential implications for diagnostic methods and antimicrobial susceptibility testing.
- A significant proportion of non-typable isolates indicates the need for updated serotyping schemes to capture local antigenic diversity.
Abstract:
During a one-year period, 258 isolates of Campylobacter jejuni and C. coli were obtained from children with gastroenteritis or bacteraemia at the Red Cross Children's Hospital, Cape Town, South Africa. These isolates were biotyped by hippurate hydrolysis, H2S production and tolerance to 2,3,5-triphenyltetrazolium chloride (TTC). Our study indicated that 95.4% of the isolates were C. jejuni biotype 1, 1.5% were C. jejuni biotype 2 and 3.1% were C. coli; 70% of the isolates were resistant to TTC. Serotyping on the basis of soluble, thermostable antigens detected by a passive-haemagglutination technique revealed that 79% of the Cape Town isolates were typable and that the most common serotypes, in order, were: 4, 2, 12, 23/36 and 19, together comprising 25% of the isolates. About 37% of the typable isolates belonged to nine serotypes. The finding that 21% of the isolates were non-typable suggests the existence of antigenic specificities different from those defined by the 60 antisera in current use.