Other bacterial diseasesStreptococcosis

Abstract

Many pyogenic (β -haemolytic) streptococci of clinical significance have animal connections. In the last edition of this book two species of streptococci were considered of major zoonotic interest, namely Streptococcus suis and S. zooepidemicus . Since then, numerous sporadic zoonoses due to other streptococci have been reported, and a newly recognized fish pathogen with zoonotic potential termed S. iniae has emerged. Changes in nomenclature make the terminology confusing. For example, the organism known as S. zooepidemicus — now termed S. dysgalactiae subsp. zooepidemicus — still causes pharyngitis in humans, complicated rarely by glomerulonephritis after ingestion of unpasteurized milk. Pigs remain the primary hosts of S. suis with human disease mainly affecting those who have contact with pigs or handle pork. Once a sporadic disease, several major epidemics associated with high mortality have been reported in China. The major change in reports of zoonotic streptococcal infections has been the emergence of severe skin and soft tissue infections, and an increasing prevalence of toxic shock, especially due to S. suis (Tang et al. 2006), group C (Keiser 1992) and group G β -haemolytic streptococci (Barnham et al. 2002). Penicillin remains the mainstay of treatment for most infections, although some strains of group C and G streptococci are tolerant (minimum bactericidal concentration difficult or impossible to achieve in vivo ) (Portnoy et al. 1981; Rolston and LeFrock 1984) and occasionally strains with increased minimum inhibitory concentrations (MIC) for penicillin are reported. Agents preventing exotoxin formation, such as clindamycin and occasionally human intravenous immunoglobulin, may be used in overwhelming infection where circulating exotoxins need to be neutralized in order to damp down the massive release of cytokines generated by their production (Darenberg et al. 2003). Prevention of human disease focuses on maintaining good hygienic practice when dealing with live animals or handling raw meat or fish products, covering skin lesions, thorough cooking of meats and pasteurization of milk.

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Identifiers

DOI

10.1093/med/9780198570028.003.0023

Journal

Oxford Medicine Online

Year

2011