A total of 58 cases of surgical site infection were observed at the facility between October 2018 and March 2019. Of these 19 (32.8%) were males while 39 (67.2%) were females with pediatric patients accounting for 3 (5.2%) of the total cases. The patients’ mean age was 31.12 years, with the youngest and eldest patient being 7 and 61 years respectively.
A total of 78 bacteria were isolated from the culture positive swabs, with monomicrobial and polymicrobial growth occurring in 60.3% (35/58) and 34.5% (20/58) of the swabs respectively. Whereas only 5.2% (3/58) of the swabs were culture negative. Staphylococcus aureus 28.2% (n=22) was the prevalent isolate followed by E.coli 15.4% (n=12), Acinetobacter species 14.1% (n=11), Pseudomonas aeruginosa 9.0% (n=7), Enterobacter species 9.0% (n=7), Bacillus species 9.0% (n=7), Coagulase negative staphylococci 5.1% (n=4), Proteus species 5.1% (n=4), Klebsiella pneumoniae 2.6% (n=2), Morganella morganii 1.3% (n=1) and Citrobacter freundii 1.3% (n=1) ( see additional file 1).
Most of the bacteria were recovered from the abdomen 60.3% and the lower limbs 29.5%, with the arms and other body sites accounting for 3.8 % and 6.4% of the total bacteria respectively (Table 1). Majority of these isolates were gram negative rods 57.7% (45) with gram positive bacteria accounting for 42.3% (33) of the total bacteria. This number was high in female patients 73.1% (57) than male patients 26.9% (21) but the difference was not statistically significant (p=0.136). Chloramphenicol 90.9% (n=30/33), Vancomycin 87.9% (n=29/33) and Doxycycline 75.8% (n=25/33) were highly sensitive to gram positive bacteria. However Azithromycin 36.4% (n=12/33) and Ampicillin (3.0%) (n=1/33) had the lowest sensitivity rates for gram positive bacteria (Table 2).
Cefepime, Gentamicin and Amikacin showed 100% resistance to Acinetobacter species and Klebsiella pneumoniae respectively. Chloramphenicol 53.3% (n=24/45) was the only drug that had the highest sensitivity for gram negative rods. Multi-drug resistance (resistance to ≥ 4 antibiotics) was observed with Klebsiella pneumoniae and E.coli (Table 3). Among gram positive bacteria, Methicillin resistant Staphylococcus aureus (MRSA) accounted for 65.4% (n=17/26) of the total Staphylococcus species (Table 2).
Table 1 Proportions of bacteria isolated from different wound sites
Wound site
|
Types and proportions of bacteria isolates
|
|
|
Gram positive bacteria N (%)
|
Gram negative bacteria N (%)
|
Total isolates
N (%)
|
Abdomen
|
24(51.1)
|
23(48.9)
|
47(60.3)
|
Lower limbs
|
7(30.4)
|
16(69.6)
|
23(29.5)
|
Arms
|
1(33.3)
|
2(66.7)
|
3(3.8)
|
Other body regions
|
1(20.0)
|
4(80.0)
|
5(6.4)
|
|
|
|
|
Table 2 Antibiotic susceptibility pattern of gram positive bacteria
Types of bacteria isolates
|
|
Tested antibiotics
|
|
|
|
|
|
VA
30ug
(%)
|
CIP 30ug
(%)
|
C
50ug
(%)
|
DO
30ug
(%)
|
AX
10ug
(%)
|
AZM
15ug
(%)
|
OX
1ug
(%)
|
Staphylococcus aureus
|
S
|
90.9
|
77.3
|
95.5
|
86.4
|
4.5
|
50.0
|
27.3
|
I
|
0.0
|
9.1
|
0.0
|
9.1
|
0.0
|
4.5
|
13.6
|
R
|
9.1
|
13.6
|
4.5
|
4.5
|
95.5
|
45.5
|
59.1
|
Coagulase negative staphylococci
|
S
|
75.0
|
100.0
|
100.0
|
50.0
|
0.0
|
25.0
|
0.0
|
I
|
25.0
|
0.0
|
0.0
|
25.0
|
0.0
|
0.0
|
0.0
|
R
|
0.0
|
0.0
|
0.0
|
25.0
|
100.0
|
75.0
|
100.0
|
Bacillus species
|
S
|
85.7
|
28.6
|
71.4
|
57.1
|
0.0
|
0.0
|
-
|
I
|
0.0
|
42.9
|
14.3
|
14.3
|
0.0
|
14.3
|
-
|
R
|
14.3
|
28.6
|
14.3
|
28.6
|
100.0
|
85.7
|
-
|
VA=vancomycin, CIP=ciprofloxacin, C=chloramphenicol, DO=doxycycline, AX=ampicillin, AZM=azithromycin, OX=oxacillin, S=sensitive, I=intermediately sensitive, R=resistant
Table 3 Antibiotic susceptibility pattern of gram negative bacteria
Types of bacteria isolates
|
|
Tested antibiotics
|
|
|
|
|
|
|
|
C
50ug
(%)
|
CIP 30ug
(%)
|
DO 30ug
(%)
|
GEN 10ug
(%)
|
COT 25ug
(%)
|
AMX 30ug
(%)
|
CPM 30ug
(%)
|
AK 30ug
(%)
|
CTR 30ug
(%)
|
Morganella morganii
|
S
|
100.0
|
0.0
|
0.0
|
100.0
|
0.0
|
0.0
|
-
|
-
|
-
|
I
|
0.0
|
100.0
|
0.0
|
0.0
|
0.0
|
0.0
|
-
|
-
|
-
|
R
|
0.0
|
0.0
|
100.0
|
0.0
|
100.0
|
100.0
|
-
|
-
|
-
|
Proteus species
|
S
|
50.0
|
50.0
|
0.0
|
100.0
|
50.0
|
0.0
|
-
|
-
|
-
|
I
|
50.0
|
50.0
|
0.0
|
0.0
|
0.0
|
0.0
|
-
|
-
|
-
|
R
|
0.0
|
0.0
|
100.0
|
0.0
|
50.0
|
100.0
|
-
|
-
|
-
|
Klebsiella pneumoniae
|
S
|
50.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
-
|
I
|
0.0
|
50.0
|
50.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
-
|
R
|
50.0
|
50.0
|
50.0
|
100.0
|
100.0
|
100.0
|
100.0
|
100.0
|
-
|
E.coli
|
S
|
41.7
|
25.0
|
33.3
|
41.7
|
0.0
|
0.0
|
16.7
|
-
|
16.7
|
I
|
0.0
|
16.7
|
0.0
|
8.3
|
0.0
|
8.3
|
0.0
|
-
|
0.0
|
R
|
58.3
|
58.3
|
66.7
|
50.0
|
100.0
|
91.7
|
83.3
|
-
|
83.3
|
Pseudomonas
aeruginosa
|
S
|
57.1
|
71.4
|
28.6
|
57.1
|
-
|
-
|
28.6
|
71.4
|
-
|
I
|
14.3
|
0.0
|
0.0
|
0.0
|
-
|
-
|
0.0
|
0.0
|
-
|
R
|
28.6
|
28.6
|
71.4
|
42.9
|
-
|
-
|
71.4
|
28.6
|
-
|
Enterobacter
species
|
S
|
85.7
|
71.4
|
42.9
|
42.9
|
42.9
|
0.0
|
-
|
-
|
-
|
I
|
0.0
|
14.3
|
0.0
|
14.3
|
0.0
|
0.0
|
-
|
-
|
-
|
R
|
14.3
|
14.3
|
57.1
|
42.9
|
57.1
|
100.0
|
-
|
-
|
-
|
Acinetobacter
species
|
S
|
36.4
|
45.5
|
27.3
|
36.4
|
-
|
-
|
0.0
|
45.5
|
-
|
I
|
45.5
|
27.3
|
9.1
|
0.0
|
-
|
-
|
0.0
|
0.0
|
-
|
R
|
18.2
|
27.3
|
63.6
|
63.6
|
-
|
-
|
100.0
|
54.5
|
-
|
Citrobacter
freundii
|
S
|
100.0
|
0.0
|
100.0
|
100.0
|
0.0
|
0.0
|
-
|
-
|
-
|
R
|
0.0
|
100.0
|
0.0
|
0.0
|
100.0
|
100.0
|
-
|
-
|
-
|
CPM=Cefepime, AK=Amikacin, CTR=Ceftriaxone, CIP=Ciprofloxacin, COT=Cotrimoxazole C=Chloramphenicol, DO=Doxycycline, GEN=Gentamicin, AMX=Amoxycillin, S=Sensitive, I=Intermediately Sensitive, R=Resistant