Group A Streptococcal Infections in Injection Drug Users in Barcelona, Spain: Epidemiologic, Clinical, and Microbiologic Analysis of 3 Clusters of Cases From 2000 to 2003

• Published in: Medicine (Baltimore) 2006-05, Vol.85 (3), p.139-146
• Main Authors: Sierra, Josep M., Sánchez, Francesca, Castro, Pedro, Salvadó, Margarita, de la Red, Gloria, Libois, Agnes, Almela, Manuel, March, Francesca, Español, Montserrat, Sambeat, Maria Antonia, Romeu, Joan, Brugal, Maria Teresa, de Olalla, Patricia García, Gatell, Jose Maria, Vila, Jordi, García, Felipe, Colomés, Jose Luís López, Caylà, Joan A., Coll, Pere
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anti-Bacterial Agents - therapeutic use; beta-Lactams - therapeutic use; Cluster Analysis; Cross Infection - drug therapy; Cross Infection - epidemiology; Cross Infection - microbiology; Disease Outbreaks; Electrophoresis, Gel, Pulsed-Field; Female; Humans; Male; Middle Aged; Molecular Epidemiology; Mutation; Population Surveillance; Prospective Studies; Restriction Mapping; Retrospective Studies; Risk Factors; Sequence Analysis, DNA; Soft Tissue Infections - drug therapy; Soft Tissue Infections - epidemiology; Soft Tissue Infections - microbiology; Spain - epidemiology; Streptococcal Infections - drug therapy; Streptococcal Infections - epidemiology; Streptococcal Infections - microbiology; Streptococcus pyogenes - drug effects; Streptococcus pyogenes - genetics; Streptococcus pyogenes - isolation & purification; Substance Abuse, Intravenous - complications; Substance Abuse, Intravenous - epidemiology; Substance Abuse, Intravenous - microbiology
• ISSN: 0025-7974
• DOI: 10.1097/01.md.0000224707.24392.52

An unexplained resurgence of Group A streptococci (GAS) infections has been observed since the mid-1980s in the United States and Europe, particularly among intravenous drug users (IDUs). Several risk factors have been identified. Mutations in the capsule synthesis regulator genes (csrRS) have been associated with an increase in virulence. From January 1998 to December 2003, we conducted a prospective and retrospective descriptive analysis of invasive GAS soft-tissue infections in IDUs in Barcelona, Spain. Clinical features were collected, and we conducted a surveillance study to identify risk factors associated with GAS soft-tissue infections. We analyzed chromosomal DNA by low cleavage restriction enzymes and used pulsed-field gel electrophoresis (PFGE) and variable gene sequence typing (VGST) of the emm gene to disclose the epidemiologic relationship between the strains. We analyzed the influence of clonality (M-type) and mutations in csrRS genes of these strains on clinical features. We identified 44 cases, all of which were grouped in 3 clusters: fall 2000, fall 2002, and fall 2003. Cellulitis with or without abscesses (75%) and fever (90.9%) were the most common clinical manifestations. Distant septic complications were infrequent (18.2%). Although all patients had severe infections (mainly bacteremic needle abscesses), their outcome with antibiotic therapy, usually beta-lactam, was successful in all cases. However, surgery was needed in 40.9% of patients. Through the surveillance study we found that infected patients had a higher number of drug injections per day (odds ratio [OR], 18.84; 95% confidence interval [CI], 4.83-79.4; p