CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 9, October 2012
AFRICA
491
A comparative study of amoxicillin, clindamycin and
chlorhexidine in the prevention of post-extraction
bacteraemia
BREMINAND MAHARAJ, YACOOB COOVADIA, AHMED C VAYEJ
Abstract
We evaluated some of the regimens recommended for the
antimicrobial prophylaxis of infective endocarditis prior to
dental extraction in 160 patients. Group A patients served as
the control group, group B subjects rinsed their mouths with
chlorhexidene, group C subjects took 3 g amoxicillin orally
and group D patients took 600 mg clindamycin orally. The
proportion of patients who had post-extraction bacteraemia
in groups A, B, C and D was 35, 40, 7.5 and 20%, respectively.
The differences between the control and amoxicillin groups
(
p
=
0.003)
and between the chlorhexidine and amoxicillin
groups (
p
=
0.0006)
were statistically significant. Streptococci
were not isolated in any patients in the amoxicillin and clin-
damycin groups. In our study, none of the regimens were
effective in preventing post-extraction bacteraemia.
Keywords:
antibiotics, prophylaxis, infective endocarditis,
dental extraction, bacteraemia
Submitted 30/11/11, accepted 5/6/12
Cardiovasc J Afr
2012;
23
: 491–494
DOI: 10.5830/CVJA-2012-049
The rationale for antibiotic prophylaxis against infective
endocarditis has been as follows: following a bacteraemia,
bacteria may lodge on damaged or abnormal heart valves or near
anatomical defects, resulting in infective endocarditis. Certain
healthcare procedures induce bacteraemia with organisms that
can cause endocarditis; these bacteria are usually sensitive to
antibiotics. Therefore antibiotics should be given to patients with
pre-disposing heart disease before procedures that may cause
bacteraemia.
1
On this basis, prophylaxis against infective endocarditis has
become routine in most countries,
2-4
even though no prospective
study has proved that it is effective.
1,4-7
The use of topical
antiseptics has been another approach to reduce the entry of
bacteria into the blood stream.
8
Since studies on the efficacy of antibiotic prophylaxis for
infective endocarditis in humans cannot be done for ethical and
practical reasons, clinical studies have focused on the prevention
of bacteraemia by administration of antimicrobial agents before
dental treatment. There is a paucity of data on the effectiveness
of amoxicillin, clindamycin and the oral antiseptic, chlorhexidine
in eliminating post-extraction bacteraemia in black patients.
We therefore carried out a study to assess and compare the
effectiveness of these drugs.
Methods
Adult black patients attending the dental clinic in Prince
Mshiyeni Memorial Hospital, Umlazi, near Durban were
included in the study after informed consent had been obtained.
They were healthy, had no history of cardiovascular disease,
had not received antibiotics in the previous two weeks and were
not allergic to penicillin. Any patient found to have a dental
abscess or who required the extraction of more than one tooth
was excluded.
Using a computer-generated randomisation table, patients
were randomised into four groups of 40 each. Group A served
as a control group and was given no therapy prior to dental
extraction. Group B rinsed their mouths vigorously with 10 ml
of 0.2% chlorhexidine for one minute and expectorated. This
procedure was repeated one minute later. Groups C and D took
3
g amoxicillin or 600 mg clindamycin orally, respectively. All
treatments were given one hour prior to the dental extraction.
Only one tooth was extracted per patient. The same dental
surgeon performed the procedure using dental forceps. No
surgical procedures were used in any patient.
The skin at the site of the venepuncture was prepared using
0.5%
chlorhexidine in 70% alcohol. Using standard aseptic
techniques, 8–10 ml of blood was drawn three minutes after the
extraction in each patient.
Three to 5 ml of blood were injected directly into BACTEC
(
Becton Dickinson, Maryland, USA) blood culture vials type 6b
(
aerobic) and 7d (anaerobic), after the used needle was replaced
with a new sterile needle, and the rubber septum on the BACTEC
vials was disinfected with alcohol. The blood culture bottles
were transported to the Microbiology Department, King Edward
VIII Hospital, Durban within two hours of collection and were
immediately incubated at 37°C. In the case of the aerobic bottles,
this also included agitation on BACTEC shakers for the first 24
hours.
The blood culture vials were tested on days one, three,
five and seven, and positive vials were sub-cultured and
Gram-stained smears were prepared. The aerobic vials were
sub-cultured onto chocolate, blood and MacConkey agar plates,
which were incubated for 48 hours in air plus 10% CO
2
.
The
anaerobic vials were sub-cultured onto 10% blood agar plates
with and without amikacin, which were incubated for 48
Department of Therapeutics and Medicines Management,
University of KwaZulu-Natal, Durban, South Africa
BREMINAND MAHARAJ, MB ChB, FCP (SA), MD, PhD, FRCP
(
London),
Department of Medical Microbiology, University of KwaZulu-
Natal, Durban, South Africa
YACOOB COOVADIA, MB ChB, FCPath (Micro)
Programme: Oral Health, Department of Health, KwaZulu-
Natal, Durban, South Africa
AHMED C VAYEJ, BDS
