Gan Xin Ning Arica¹, Wong Bao Xin Eugene¹, Tan Yen Ee^1
1Department of Microbiology, Singapore General Hospital.

Introduction: Campylobacter upsaliensis was brought to Singapore General Hospital (SGH) Diagnostic Bacteriology Laboratory’s attention in 2022. It was the organism of interest in RCPA survey, MI-FP-22-07. Unfortunately, current stool laboratory practices adopted by SGH failed to recover the organism. 

C. upsaliensis can grow on blood agar media and is reliably identified by mass spectrometry. Unlike C. jejuni and C. coli, it is more susceptible to cephalothin and cefoperazone1 (antibiotics commonly used in Campylobacter selective media), which may have accounted for its lack of recovery. 

The aim of this study is to determine the prevalence of C. upsaliensis in stool samples received in SGH and to assess the need to revise the current laboratory protocol to screen for it.

Method: This study included 149 SGH clinical stool samples collected in August 2024. Alongside routine laboratory practices, an additional blood plate was inoculated and incubated in microaerophilic conditions at 42°C for 48 hours. Any suspicious colonies were sent for identification using mass spectrometry. 

Conclusion: No C. upsaliensis was isolated amongst the 149 stool cultures. Its prevalence may be low in SGH population and screening for it may not be necessary. Resources should be focused on more common pathogens instead.

References:
Bourke B., Chan V.L & Sherman P., 1998. Campylobacter upsaliensis: Waiting in the Wings. American Society for Microbiology, 1998, pp. 440-449.

Acknowledgements:
The study was performed by Gan Xin Ning Arica and Wong Bao Xin Eugene, with valuable feedback and insights from Dr Tan Yen Ee.