Beta Haemolytic Streptococcal Pharyngitis

• Streptococci are facultatively anaerobic, Gram-positive organisms
• most important groupable streptococci are A, B and D
• Three types of hemolysis reaction (alpha, beta, gamma) are seen after growth of streptococci on sheep blood agar
• Group A and group B streptococci are beta hemolytic, whilst D are usually alpha or gamma.
• Infections similar to those caused by Group A Streptococci are occasionally caused by Group C and G beta-hemolytic streptococci.

Treatment

Streptococcus pyogenes (group A beta-hemolytic streptococcus)
Adult dosage	penicillin allergic	Pediatric dosage	penicillin allergic
·         Penicillin V 500 mg PO BID for 10d or ·         Benzathine penicillin G 1.2 million U IM once or ·         Amoxicillin 500-875 mg PO q12h or 250-500 PO q8h for 10d or ·         Cephalexin 500 mg PO BID for 10d or ·         Cefdinir 600 mg PO once daily for 10d or ·         Cefprozil 500 mg PO once daily for 10d	·         Azithromycin 500 mg PO daily for 5d or ·         Clarithromycin 250 mg PO q12h for 10d or ·         Clindamycin 20 mg/kg/day in 3 divided doses (maximum 1.8 g/day) for 10d	·         Penicillin V 25-50 mg/kg/day divided q6h for 10d or ·         Benzathine penicillin G 25,000 U/kg IM once (maximum 1.2 million U) or ·         Amoxicillin 50 mg/kg/day PO in 2 or 3 divided doses for 10d or ·         Amoxicillin-clavulanate 500-875 mg PO q12h for 10d or ·         Cefuroxime axetil 20 mg/kg/day in 2 divided doses for 4-10d or ·         Cefdinir 14 mg/kg q24h for 10d or ·         Cefprozil 15 mg/kg/day in 2 divided doses for 10d	·         Azithromycin 12 mg/kg PO once daily for 5d or ·         Clarithromycin 250 mg PO q12h for 10d or ·         Clindamycin 20 mg/kg/day PO in 3 divided doses (maximum 1.8 g/day) for 10d
Group B, C and G beta-hemolytic streptococci
·         Penicillin V 500 mg PO BID for 10d or ·         Benzathine penicillin G 1.2 million U IM once or ·         Amoxicillin 500-875 mg PO q12h or 250-500 PO q8h for 10d	·         Azithromycin 500 mg PO daily for 5d or ·         Clarithromycin 250 mg PO q12h for 10d or ·         Clindamycin 20 mg/kg/day in 3 divided doses (maximum 1.8 g/day) for 10d	·         Penicillin V 25-50 mg/kg/day divided q6h for 10d or ·         Benzathine penicillin G 25,000 U/kg IM once (maximum 1.2 million U) or ·         Amoxicillin 50 mg/kg/day PO in 2 or 3 divided doses for 10d	·         Azithromycin 12 mg/kg PO once daily for 5d or ·         Clarithromycin 250 mg PO q12h for 10d or ·         Clindamycin 20 mg/kg/day PO in 3 divided doses (maximum 1.8 g/day) for 10d

References

1. http://www.microbiologybook.org/fox/streptococci.htm
2. http://www.aafp.org/afp/2001/0415/p1557.html
3. http://emedicine.medscape.com/article/2011872-overview
4. http://www.emedexpert.com/conditions/strep-throat.shtml
5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2238097/pdf/0985-07.pdf