Clostridioides (Clostridium) difficile isolated from paediatric patients in Western Australia 2019-2020

Less is understood about the epidemiology of Clostridioides difficile infection (CDI) in children compared to adults, and its impact is complicated by variations in the natural development of infection in paediatric patients. The interplay of rising CDI incidence in hospitalised paediatric patients, emergence of hypervirulent strains and community associated CDI (CA-CDI) in the past decade is a potential threat in both hospital and community settings. Research in Australia regarding paediatric CDI is limited. Here, we report the molecular characterisation of C. difficile isolated from paediatric patients at a tertiary hospital in Perth, Western Australia. A total of 427 stool samples was collected from patients aged from <1 to 17 years being investigated for diarrhoea from July 2019 to June 2020. Stool specimens were cultured and isolates of C. difficile characterised by ribotyping and toxin gene profiling. Clostridioides difficile was recovered from 84/427 (19.7%) samples tested. The most prevalent PCR ribotypes (RTs) were RT 002 (12.4%), a toxigenic strain, and RT 009 (15.7%), a non-toxigenic strain. Interestingly, C. difficile RT 078 and RT 017, strains that are not endemic in Australia, were isolated from a 1- and 4-year old child, respectively. Clostridioides difficile RT 106, a strain of emerging importance in Australia, was recovered from two cases (5.3%). Resistance to metronidazole, fidaxomicin, amoxicillin, rifaximin and meropenem was not detected, however, 45 isolates (50.6%) showed resistance to at least one agent, and multidrug resistance was observed in 13.3% of the resistant isolates (6/45). This study provides a baseline for future surveillance of paediatric CDI in Australia. Given that young children can be asymptomatically colonised with toxigenic C. difficile strains, they represent a potential reservoir of strains causing CDI in adults.