CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 6, July 2012
AFRICA
341
The frequency of bacteraemia following dental
extraction
In this part of the study, 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 immediately prior to and
at two, five, 15 and 30 minutes after the extraction in each patient.
Three to 5 ml of blood was injected directly into BACTEC
(Becton Dickinson, Maryland, USA) blood culture vials type 6b
(aerobic) and 7d (anaerobic), respectively, 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 to 72 hours in anaerobic
gas pak (Becton Dickinson, USA) jars with appropriate controls.
The organisms isolated were further identified using
conventional laboratory methods and the identity of streptococcal
isolates was confirmed using the API Strep 20 (API, France)
system.
17
The frequency of bacteraemia following tooth
brushing
In this part of the study, patients were instructed on the proper
technique of tooth brushing by the dental surgeon. Thereafter
they brushed their teeth for about five minutes using a new soft
toothbrush and toothpaste.
The skin preparation and the techniques for blood collection
and blood culture were similar to the first part of the study.
The timing of the blood sampling was immediately prior
to, immediately after, and at five and 15 minutes after tooth
brushing.
The frequency of bacteraemia following chewing
In this part of the study, patients were asked to chew an apple.
The skin preparation and the techniques for blood collection
and blood culture were similar to the first part of the study.
The timing of the blood sampling was immediately prior to
commencement of chewing, when half the apple had been eaten,
when the whole apple had been eaten, and five minutes later.
Statistical analysis
In each part of the study, the patients with plaque and gingival
index scores rated as excellent, good, average and poor were
placed in their respective groups and the number of patients
with positive blood cultures in each group was compared using
the Chi-square test. A
p
-value
<
0.05 was chosen as the level of
significance.
Results
The frequency of bacteraemia following dental
extraction
A total of 108 black patients participated in the study. There were
60 males and 48 females. Their ages ranged from 16 to 66 years
(mean 29.5).
No patient had a plaque or gingival index score that was rated
as excellent. One patient who had a plaque and gingival index
score rated as poor had a bacteraemia prior to dental extraction.
Bacteroides fragilis
was detected on anaerobic culture.
Post-extraction bacteraemia was detected in 32 (29.6%)
patients and was transient in all patients. No bacteria were
detected at 15 or 30 minutes. The organisms cultured after dental
extraction are listed in Table 1. The number of patients who had
positive blood cultures in the groups with good, fair and poor
plaque and gingival index scores are shown in Tables 2 and 3.
The frequency of bacteraemia following tooth
brushing
Seventy-four black patients, 39 males and 35 females, entered
the study. Their ages ranged from 16 to 63 years (mean 26.6).
No patient had a plaque or gingival index score that was rated
as excellent.
No bacteraemia was detected prior to tooth brushing.
Bacteraemia was detected in eight (10.8%) patients after tooth
TABLE 1. ORGANISMS CULTUREDAFTER DENTAL
EXTRACTION
Aerobic cultures
No. Anaerobic cultures
No.
Streptococcus mitis
Streptococcus sanguis
Streptococcus anginosus
group
Streptococcus
species
Staphylococcus epidermidis
Enterococcus faecalis
Moraxella catarrhalis
Neiserria sicca
Corynebacterium ulcerans
Corynebacterium xerosis
5
4
4
6
1
2
1
1
1
1
Streptococcus mitis
Streptococcus sanguis
Streptococcus anginosus
group
Viridans streptococci
Streptococcus
species
Staphylococcus epidermidis
Enterococcus faecalis
Moraxella catarrhalis
Neiserria sicca
Corynebacterium ulcerans
Corynebacterium xerosis
Prevotella melaninogenica
Capnocytophaga
species
Gram-negative bacilli
5
1
4
1
5
2
1
1
1
1
1
1
1
1
TABLE 2. PATIENTSWITH POSITIVE CULTURESAFTER
DENTAL EXTRACTION IN RELATION TO PLAQUE INDEX*
Plaque index score
No. in group No. positive
% positive
Good
Fair
Poor
36
37
35
10
12
10
27.8
32.4
28.6
*Differences between the groups were not statistically significant.
TABLE 3. PATIENTSWITH POSITIVE CULTURESAFTER
DENTAL EXTRACTION IN RELATION TO GINGIVAL INDEX*
Gingival index score
No. in group No. positive
% positive
Good
Fair
Poor
38
34
36
9
12
11
23.7
35.3
30.6
*Differences between the groups were not statistically significant.
