Throat culture positivity rate and antibiotic susceptibility pattern of beta-hemolytic streptococci in children on secondary prophylaxis for rheumatic heart disease.
BACKGROUND
Among children diagnosed to have chronic rheumatic valvular heart disease (RHD) in Ethiopia, many have been observed to develop recurrence of rheumatic fever (RF) despite secondary prophylaxis. This study determined the throat culture positivity rate and drug susceptibility pattern of beta hemolytic streptococci (BHS) isolated from children attending a specialized cardiac clinic in Ethiopia.


METHODS
Throat swabs were collected from 233 children receiving benzathine penicillin injection as secondary prophylaxis for RHD and cultured. The bacterial isolates were characterized using Matrix Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) mass spectrometry. Drug susceptibility was tested with the Kirby Bauer disc diffusion method. Anti-streptolysin O (ASO) titers were determined using ASO latex reagents.


RESULTS
The throat culture positivity rate for BHS was 24 % (56/233). Among the BHS bacterial strains isolated, four were characterized as S. pyogenes and another four as S. dysgalactiae subsp. equisimilis (Lancefield group A, C and G). All BHS were susceptible to penicillin except one isolate of S. agalactiae. Among 233 children enrolled, 46(19.7 %) showed increased ASO titer. Children who received antibiotic prophylaxis within 2-weeks of last injection had significantly lower BHS throat culture positivity rate than those injected every 4-weeks (p = 0.02). Children who missed at least one prophylaxis within the last 6 months had a higher BHS culture positivity rate than those who did not miss any (p = 0.0003).


CONCLUSIONS
The presence of groups A, C and G streptococci in the throat of children under secondary prophylaxis for RHD and increased ASO titer suggests failure of the regimen. This calls for further investigation into the causes of inadequate prophylaxis (including bioavailability of drugs used, optimal duration and patient compliance) and intervention.
Department of Medicine, DebreBerhan University, P. O. Box: 445, DebreBerhan, Ethiopia. kingster2002@gmail.com.|Armauer Hansen Research Institute, Jimma Road, PO Box 1005, Addis Ababa, Ethiopia. kingster2002@gmail.com.|Department of Microbiology, Immunology and Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia. kingster2002@gmail.com.
Nigus
N
Zegeye
Department of Microbiology, Immunology and Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
Daniel
D
Asrat
Department of Microbiology, Immunology and Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
Yimtubezinash
Y
Woldeamanuel
Armauer Hansen Research Institute, Jimma Road, PO Box 1005, Addis Ababa, Ethiopia.
Abebe
A
Habte
Department of Pediatrics and Child Health, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
Etsegenet
E
Gedlu
Department of Microbiology, Oslo University Hospital, Oslo, Norway.|Department of Microbiology, University of Oslo, Oslo, Norway.
Tone
T
Tønjum
Armauer Hansen Research Institute, Jimma Road, PO Box 1005, Addis Ababa, Ethiopia.
Abraham
A
Aseffa
Antibiotic prophylaxis; Antibiotic resistance; Beta hemolytic streptococci (BHS); Ethiopia; Rheumatic fever (RF); Rheumatic heart disease (RHD); Streptococcus dysgalactiae subsp. equisimilis; Streptococcus pyogenes
J Med Microbiol. 2010 Feb;59(Pt 2):220-3
19833781
Eur J Clin Microbiol Infect Dis. 2014 Aug;33(8):1303-10
24682845
Cardiology. 1992;80(2):152-5
1611634
Lancet Infect Dis. 2005 Nov;5(11):685-94
16253886
Med Dosw Mikrobiol. 2012;64(1):1-10
22808724
Clin Infect Dis. 2009 Aug 15;49(4):543-51
19583519
Ethiop J Health Sci. 2010 Jul;20(2):99-105
22434967
J Clin Microbiol. 1999 Dec;37(12):4194-7
10565964
World Health Organ Tech Rep Ser. 1988;764:1-58
3131967
Kansenshogaku Zasshi. 2002 Mar;76(3):155-60
11974882
Lancet. 2006 Feb 4;367(9508):391
16458755
Pediatrics. 2012 Mar;129(3):e798-802
22311996
Epidemiol Infect. 1992 Oct;109(2):211-25
1397112
Int J Infect Dis. 2009 Jul;13(4):421-4
19128997
DNA Seq. 1994;4(5):325-8
7803818
East Afr Med J. 1999 Nov;76(11):601-5
10734517
Pediatr Infect Dis J. 2012 Jul;31(7):722-5
22481428
J Clin Microbiol. 2010 Oct;48(10):3770-2
20668133
Clin Infect Dis. 2006 Dec 1;43(11):1398-406
17083011
J Clin Microbiol. 2006 Aug;44(8):2721-7
16891483
Pediatr Rep. 2012 Jan 2;4(1):e8
22690314
Pediatr Cardiol. 2010 Aug;31(6):849-52
20411251
Pediatr Infect Dis J. 2001 Sep;20(9):863-8
11734765
BMC Infect Dis. 2014 Mar 29;14:174
24678588
Lancet. 2005 Jul 9-15;366(9480):155-68
16005340
Ethiop Med J. 2004 Jan;42(1):1-8
15884271
J Clin Microbiol. 1976 Aug;4(2):192-3
965480
Br J Rheumatol. 1998 Dec;37(12):1343-8
9973162
Medicine (Baltimore). 1985 Mar;64(2):75-88
3974442
Pediatrics. 1995 Oct;96(4 Pt 1):758-64
7567345
East Mediterr Health J. 2000 Mar-May;6(2-3):437-46
11556035
Chemotherapy. 1997 Jan-Feb;43(1):10-20
8996736
Indian Heart J. 2012 Jan-Feb;64(1):12-5
22572418
Ethiop Med J. 2011 Apr;49(2):125-30
21796912
Clin Infect Dis. 2009 Sep 1;49(5):766-72
19635028
Autoimmun Rev. 2009 Dec;9(2):117-23
19386288
J Clin Microbiol. 2006 Sep;44(9):3346-51
16954271
Pediatrics. 2001 Nov;108(5):1180-6
11694700
Cochrane Database Syst Rev. 2002;(3):CD002227
12137650
J Paediatr Child Health. 2011 Apr;47(4):228-34
21470327
J Infect Dev Ctries. 2011 Nov 15;5(11):804-8
22112735
Emerg Infect Dis. 2007 Nov;13(11):1694-700
18217553