High Perineal and Overall Frequency of Staphylococcus aureus in People Who Inject Drugs, Compared to Non-Injectors

Disa Dahlman,Marianne Alanko Blomé,Håkan Janson,Farnaz Jalalvand,Susanne Quick,Anders Håkansson,Anna C Nilsson

doi:10.1007/s00284-016-1165-y

Disa Dahlman, Marianne Alanko Blomé + Show 5 more

Open Access

https://doi.org/10.1007/s00284-016-1165-y

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Abstract

To investigate the prevalence, distribution, and colonization burden of Staphylococcus aureus (S. aureus) and MRSA in different body sites among people who inject drugs (PWID) and compare it to a control group consisting of non-injectors. In this cross-sectional survey, 49 active PWID from the needle exchange program (NEP) in Malmö, Sweden, and 60 non-injecting controls from an emergency psychiatric inpatient ward at Malmö Addiction Centre were tested for S. aureus (including MRSA) by culture, PCR, and MALDI-TOF. Samples were taken from anterior nares, throat, perineum, and skin lesions if present. Sixty-seven percent of the PWID were colonized with S. aureus, compared to 50% of the controls (P = 0.08). Perineal carriage was significantly more frequent among PWID than in the control group [37 vs 17%, OR 2.96 (95% CI 1.13–7.75), P = 0.03], also after adjusting for sex and age in multivariate analysis [OR 4.01 (95% CI 1.34–12.03)]. Only one individual in the whole cohort (NEP participant) tested positive for MRSA. PWID may be more frequently colonized with S. aureus in the perineum than non-injection drug users, and there was a trend indicating more frequent overall S. aureus colonization in PWID, as well as higher perineal colonization burden. No indication of a high MRSA prevalence among PWID in Sweden was noted. However, further MRSA prevalence studies among PWID are needed. Knowledge about S. aureus colonization is important for the prevention of S. aureus infections with high morbidity in PWID.

Highlights

People who inject drugs (PWID) are at increased risk for superficial and invasive infections with Staphylococcus aureus (S. aureus), resulting in increased length of hospitalization, mortality and economic cost [16, 45]
The high percentage of 67% S. aureus culture positive people who inject drugs (PWID) at Malmo needle exchange program (NEP) is, not in agreement with the 39% obtained by Bassetti et al, who found a lower prevalence rate when comparing PWID with non-injectors [6]
These contrasting results may partly be explained by the fact that the maintenance program studied by Bassetti et al assisted in injections, in addition to the provision of sterile equipment, while no supervised or assisted injections take place at Malmo NEP

Summary

Introduction

People who inject drugs (PWID) are at increased risk for superficial and invasive infections with Staphylococcus aureus (S. aureus), resulting in increased length of hospitalization, mortality and economic cost [16, 45]. PWID are more frequently colonized with S. aureus than the average population (35% of recent injectors compared to 11% in healthy controls, P \ 0.05) [42], with nasal colonization in 28–45% [1, 17, 22]. Another concern regarding S. aureus is the development and spread of methicillin-resistant S. aureus (MRSA) [4]. It is suggested that S. aureus infections originate from endogenous nasal bacteria that are spread to the skin, which in turn cause infection when the integrity of

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