Campylobacter jejuni is responsible for most foodborne bacterial infections worldwide including Australia.
Campylobacteriosis is generally sporadic in nature and outbreaks
have rarely been reported. The aim of this study was to investigate the usefulness of a
combination of typing methods in characterization of
C. jejuni isolated from human diarrhoeal samples and chicken meat, differentiation of isolates from outbreak and non-outbreak regions and ranking of isolates based on their relative risk to humans. A total of 48
Campylobacter jejuni isolates
from human (n=22) and poultry (n=26) were utilized in this study. Sequencing of the
flaA
short variable region (SVR) demonstrated that
86% (19/22) of the human isolates had genotypes that were also found in chicken meat.
A PCR binary typing system indicated that not all isolates were of equal risk
to human health. The cell surface structure, lipooligosaccharide (LOS), of
C. jejuni
isolates was also studied in this project.
C. jejuni isolates were classified into six LOS classes (A,
B, C, E, F and H) and 10.4% remain unclassified. The majority of clinical isolates (73%)
possessed the sialylated LOS classes (A, B and C).
Interestingly, sialylated LOS classes were also detected in chicken (81%).
This could be considered as further evidence for
the importance of poultry as a potential vehicle for campylobacteriosis. Sialylated LOS classes showed
concordance with specific
flaA-SVR types, although the sample size was small. Further investigation using antimicrobial tests indicated a low level of resistance
to commonly used antimicrobial agents. The overall prevalence of antimicrobial resistance
was 10%, of which 80% of antimicrobial-resistant
isolates were of poultry origin.
The detection of florfenicol resistance in
Australian isolates has not been detected before and warrants additional
investigation with a larger sample size.