|Cultures of Streptococcus anginosus on blood agar|
Cultures of Streptococcus anginosus on blood agar
Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Streptococcus anginosus is a species of Streptococcus. Together with Streptococcus constellatus and Streptococcus intermedius they constitute the anginosus group, which is sometimes also referred to as the milleri group after the previously assumed single but later refuted species Streptococcus milleri. Phylogenetic relatedness of S. anginosus, S. constellatus, and S. intermedius has been confirmed by rRNA sequence analysis.
The majority of Streptococcus anginosus strains produce acetoin from glucose, ferment lactose, trehalose, salicin, and sucrose, and hydrolyze esculin and arginine. Carbon dioxide can stimulate growth or is even required for growth in certain strains. Streptococcus anginosus may be beta-hemolytic or nonhemolytic. Among the nonhemolytic strains, certain ones produced the alpha reaction on blood agar. However, of isolates examined in one study, 56% were nonreactive, 25% were beta reactive, and only 19% were alpha reactive.
Streptococcus anginosus is part of the human bacteria flora, but can cause diseases including brain and liver abscesses under certain circumstances. The habitat of S. anginosus is a wide variety of sites inside the human body. Cultures have been taken from the mouth, throat, feces, and vagina, yielding both hemolytic (mouth) and nonhemolytic (fecal and vaginal strains). Because of the commonplace with this bacterium and the human body, there are a number of infections that are caused by S. anginosus.
Pyogenic liver abscess is associated with S. anginosus and in studies in the 1970s was reported to be the most common cause of hepatic abscess. It was also reported that S. anginosus rarely causes infections in healthy individuals but instead it is usually the immunodeficient individuals who were victim to this bacterium. A case study was reported on a 40 year old man who frequently drank alcohol and had poor oral hygiene. He was admitted to hospital with high fever and malaise. During diagnostic testing, a abscess was found on his liver, from which 550cc of hemopurulent exudate was drained. The exudate was cultured and S. anginosus was found. Disc diffusion technique revealed that bacterium was sensitive to penicillin. Patient was asymptomatic on 30th day of treatment. It was noted that the duration of symptoms is longer with liver abscesses associated with S. aginosus than with other microorganisms.
Another study showed a case with a diagnosis of sympathetic empyema that was likely secondary to splenic abscess. Cultures of both sites grew Streptococcus anginosus. The empyema responded well to treatments however the splenic abscess required three weeks of drainage before the abscess resolved. Authors noted that there were no known cases of sympathetic empyema caused by Streptococcus anginosus.
There are several antimicrobial resistant strains of this bacterium. Most Streptococcus milleri strains are resistant to bacitracin and nitrofurazone, and sulfonamides are totally ineffective. However, most strains studied have been shown to be susceptible to penicillin, ampicillin, erythromycin, and tetracycline.
- 1. Dental abscess
- Preferred regimen: Penicillin V 500 mg PO qid
- Alternative regimen: Vancomycin 15–20 mg/kg IV q8–12h
- 2. Brain abscess
- Preferred regimen (1): Penicillin G 18–24 MU/day IV q4–6h
- Preferred regimen (2): Ceftriaxone 2 g IV q12h
- Alternative regimen: Vancomycin 15–20 mg/kg IV q8–12h
Blood agar plate inoculated with a culture of Streptococcus anginosus bacteria. From Public Health Image Library (PHIL). 
Blood agar plate (BAP) with a culture of Streptococcus anginosus displaying "wide zone alpha hemolytic" (WZα) color changes. From Public Health Image Library (PHIL). 
- ↑ Morita E, Narikiyo M, Yokoyama A; et al. (December 2005). "Predominant presence of Streptococcus anginosus in the saliva of alcoholics". Oral Microbiol. Immunol. 20 (6): 362–5. doi:10.1111/j.1399-302X.2005.00242.x. PMID 16238596.
- ↑ Jacobs, JA (May 2000). "The Streptococcus anginosus species comprises five 16S rRNA ribogroups with different phenotypic characteristics and clinical relevance". International journal of systematic and evolutionary microbiology. 50 (3): 1073–9. doi:10.1099/00207713-50-3-1073. PMID 10843047. Unknown parameter
- ↑ 3.0 3.1 Ruoff, KL (January 1988). "Streptococcus anginosus ("Streptococcus milleri"): the unrecognized pathogen". Clinical Microbiology Reviews. 1 (1): 102–8. doi:10.1128/CMR.1.1.102. PMC 358032. PMID 3060239.
- ↑ Ball, Lyn C. (14 May 2009). "The cultural and biochemical characters of Streptococcus milleri strains isolated from human sources". Journal of Hygiene. 82 (01): 63–78. doi:10.1017/S002217240002547X. PMID 762404. Unknown parameter
- ↑ Yilmaz, hava (1 June 2012). "Liver abscess associated with an oral flora bacterium Streptococcus anginosus". Journal of Microbiology and Infectious Diseases. 2 (1): 33–35. doi:10.5799/ahinjs.02.2012.01.0039.
- ↑ Wissa, Raschke, Mathew. "Sympathetic Empyema Arising from Streptococcus anginosus Splenic Abscess." Southwest Journal of Pulmonary and Critical Care. 2012. Vol. 4, pp48-50
- ↑ Poole, P M (1 August 1976). "Infection with minute-colony-forming beta-haemolytic streptococci". Journal of Clinical Pathology. 29 (8): 740–745. doi:10.1136/jcp.29.8.740. PMC 476157. PMID 956456. Unknown parameter
- ↑ Shlaes, et al. "Infections due to Lancefield group F and related streptococci." Medicine(Baltimore) 60:197-207
- ↑ Abramowicz, Mark (2011). Handbook of antimicrobial therapy : selected articles from Treatment guidelines with updates from The medical letter. New Rochelle, N.Y: The Medical Letter. ISBN 978-0981527826.
- ↑ 10.0 10.1 "Public Health Image Library (PHIL)".