Looking under rocks: Skin infections in people who use drugs: a mixed-methods investigation in Wales

 
Background:
Public Health Wales were notified in September 2022 of 8 cases of group A Streptococcus (GAS) infection in people who use drugs (PWUD), one of which was invasive (iGAS). All cases were typed emm 108.1 and clustered within 0-3 single nucleotide polymorphisms. In contrast to previous GAS outbreaks, within PWUD, all cases smoked crack cocaine. There is limited literature on GAS/iGAS outbreaks in individuals who smoke crack cocaine. To date the focus of harm reduction interventions has been to mitigate the harms associated with injecting. We used the evidence to inform drug inhalation harm reduction measures in Wales. 
Methods:
A case definition was developed, and a mixed methods questionnaire captured demographics, current and historical drug use practices, and infection history. The questionnaire was delivered in person and was completed by 10 cases. Answers were transcribed and open-ended responses reviewed thematically. 
Results:
70% of respondents were female. All cases reported smoking crack cocaine. 70% reported injecting drugs in the 4 weeks before infection. Respondents’ knowledge and active engagement in harm reduction practices to reduce risk from injecting drug use was evident. In contrast, 90% reported sharing crack pipes, smoking group sizes ranged from 1-15 people, and only 20% decontaminated pipes before use. Rushed crack smoking was frequently reported. Findings highlighted the strength of the social context and relational factors in influencing crack smoking practices. 
Conclusion:
It was concluded that sharing of the crack pipes was the most likely source of the infection, which to our knowledge has not been documented in literature of similar investigations. Smoking group size and social context is as important factor to consider when managing clusters of GAS/iGAS infections among PWUD. The high representation of female cases does not reflect the male-dominated case mix of previous published outbreaks. Recommendations to strengthen harm reduction messaging and interventions for crack smoking are made. Service providers should be alerted to recognise and respond to non-injecting related bacterial infections among people who use drugs, with a gender sensitive approach.