CAMPYAIR, a new medium for Campylobacter spp. isolation without the need for microaerobic atmosphere

Authors: LEVICAN, ARTURO - Departamento De Ingeniería Hidráulica Y Ambiental, Pontificia Universidad Cato´lica De Chile; Hinton Jr, Arthur

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2022
Publication Date: 7/12/2022
Citation: Levican, A., Hinton Jr, A. 2022. CAMPYAIR, a new medium for Campylobacter spp. isolation without the need for microaerobic atmosphere. Microorganisms. https://doi.org/10.3390/microorganisms10071403.
DOI: https://doi.org/10.3390/microorganisms10071403

Interpretive Summary: Campylobacter are considered the most frequent cause of acute bacterial gastroenteritis in humans, worldwide. Diarrhea produced by these bacteria is self-limiting, but Campylobacter infections have been associated with severe long-term sequelae such as Guillain-Barré syndrome. However, research on this pathogen is sometimes limited by costs and technical requirements required to grow the bacterium. Therefore, attempts have been made to reduce culturing costs and to simplify culturing methods. In the present study, a selective, liquid medium that allows growth of Campylobacter without the production of microaerophilic atmospheres was modified to formulate a new solid medium. The medium was also supplemented with additional antibiotics to determine if the growth of non-Campylobacter found in environmental samples could be decreased. Also, a color indicator was added to the medium to aid in the identification of Campylobacter because of the distinct color produced by these bacteria growing on the medium. Results indicated that the new solid medium, CAMPYAIR, supported the Campylobacter growth after 48 hours of incubation in sealed agar plates incubated aerobically. Furthermore, the addition of other antibiotics decreased the growth of bacterial contaminants without decreasing Campylobacter growth, while the indicator allowed presumptive identification of the pathogen. These findings suggest that the utilization of CAMPYAIR medium may reduce the costs, equipment, and technical training required for Campylobacter isolation from clinical or environmental samples.

Technical Abstract: Campylobacter spp., especially Campylobacter jejuni and Campylobacter coli are considered the most frequent bacterial cause of acute gastroenteritis worldwide. In fact, despite the decrease in laboratory reporting of gastrointestinal pathogens due to the prioritizationof Sars-CoV-2 testing over routine testing during the COVID pandemic, Campylobacter infections decreased less compared with other pathogens. Although the diarrhoea produced by these bacteria is self-limiting, it has been associated with severe long-term sequelae such as Guillain-Barré syndrome. However, so far, the searching for Campylobacter in clinical samples is hampered by its costs and technical requirements, specially in low and middle-income countries where its real burden is poorly understood. For this reason, attempts have been made to reduce costs of and simplify culture methods, and in this line, it has been obtained a liquid medium which allows selective enrichment of Campylobacter under aerobic conditions. However, in routine laboratories the isolation of colonies can only be obtained by using solid medium. Therefore, the present study was aimed to propose a new solid medium with that characteristic, based on the liquid medium previously proposed. Moreover, different antibiotic supplements were tested to assess the potential utility of this new medium to isolate Campylobacter spp. from complex matrices such as human faeces or foods. The new solid medium named CAMPYAIR supported the aerobic Campylobacter growth after 48 hours of incubation of collection and field strains of C. jejuni and C. coli which could be easily recognized by its colour. Moreover, the combination of the antibiotic supplement CCDA plus 10 ug/L vancomycin inhibited other bacteria able to hamper the growth of Campylobacter in complex samples. Altogether, these findings suggest that the utilization of this medium could help to reduce the costs, equipment, and technical training required for Campylobacter isolation from clinical or environmental samples, enhancing the detection of these bacteria.