Study flow:
One hundred and eighty (180) outpatients at Kagando hospital suspected by the clinician of having salmonellosis were screened for eligibility to participate in the study. After excluding 15 (8.3%) outpatients who did not fulfill the inclusion criteria (failed to provide the study samples) or declined to participate in the study, 165 (91.7%) outpatients were enrolled as study participants in a cross sectional study as shown in figure 1 below.
Demographic description of study participants.
Males were 88 out of 165 (53%) while females were 77 out of 165 (47%). Majority of study participants were aged between 4 to 24 years and these were 72 (44%), those aged 25 to 40 years were 46 (28%) and those aged 41 and above were 47 (28%). Mean age for males was 30 years while females had a mean age of 32 years with overall mean age of 31 years. Majority of study participants came from nuclear families 119 (72%) while the rest 46 (28%) came from extended families. Most of the study participants were married and these accounted for 83 (50.3%) followed by single participants 80 (48.5%) and then finally separated participants 2 (1.2%). Most study participants had achieved tertiary level of education 59 (36%), then followed by those with primary level 50 (30%), then secondary level 45 (27%), and then finally non-educated 11 (7 %.) as shown in table 1 below.
Table 1: Demographic description of study participants.
Variable
|
Frequency (percentage )
|
Age categories (years)
|
|
4-24
|
72 (44%)
|
25-40
|
46 (28%)
|
41 and above
|
47 (28%)
|
Gender
|
|
Females
|
77 (47%)
|
Males
|
88 (53%)
|
Marital status
|
|
Separated
|
2 (1.2%)
|
Single
|
80 (48.5%)
|
Married
|
83 (50.3%)
|
Education level
|
|
No education
|
11 (7%)
|
Primary
|
50 (30%)
|
Secondary
|
45 (27%)
|
Tertiary
|
59 (36%)
|
Family setting
|
|
Nuclear
|
119 (72%)
|
Extended
|
46 (28%)
|
Overall prevalence of Salmonella infection (typhoid, paratyphoid and non-typhi salmonellosis).
The sero prevalence of salmonellosis by Salmonella Typhi/Paratyphi IgM/IgG serological testing was 22% (36 positive out of 165 study participants) as shown in table 2 below
Table 2: Prevalence of salmonellosis by Salmonella Typhi/Paratyphi IgM/IgG by serological testing.
Salmonella typhi/paratyphi IgM/IgG result
|
Frequency
|
Prevalence (%)
|
Positive
|
36
|
22
|
Negative
|
129
|
78
|
Total
|
165
|
100
|
Blood and stool culture was positive for 26 study participants out 165, giving a general prevalence of 15.8%. Of the 26 isolates 65.4% (17 out of 26) were Non-typhi salmonella, 30.8% (8 out of 26) were Salmonella Typhi and 3.8 % (1 out of 26) was Salmonella Paratyphi. Non-Typhi Salmonella accounted for a prevalence of 10.3% (17 out of 165) followed by Salmonella Typhi with a prevalence of 4.9% (8 out of 165) and then finally Salmonella Paratyphi with prevalence of 0.61% (1 out of 165) as shown in figure 2 below
Of the 165 study participants, 6 (3%) had a positive culture of blood or stool for Salmonella (either Typhi or Paratyphi or NTS) and a positive Salmonella Typhi/Paratyphi IgM/IgG test, 20 (12.1%) had a positive culture of blood or stool for Salmonella (either Typhi or Paratyphi or NTS) and a negative Salmonella Typhi/Paratyphi IgM/IgG test, 30 (18.2%) had a positive Salmonella Typhi/Paratyphi IgM/IgG test and a negative culture of blood or stool for Salmonella (either Typhi or Paratyphi or NTS, and finally 109 (66.1%) had both culture of stool or blood and Salmonella Typhi/Paratyphi IgM/IgG test negative as shown in table 3 below.
Table 3: Comparison of Salmonella Typhi/Paratyphi IgM/IgG test with Culture of stool and blood.
|
Blood and stool culture
|
Salmonella Typhi/Paratyphi IgM/IgG test
|
|
Positive Salmonellosis (%)
|
Negative Salmonellosis (%)
|
Total
|
Test positive
|
06 (3.6%)
|
30 (18.2%)
|
36
|
Test negative
|
20 (12.1%)
|
109 (66.1%)
|
129
|
Total
|
26
|
139
|
165
|
Description of the susceptibility of salmonella isolates to selected antibiotics.
a.) Levofloxacin (LEV): Of the 26 salmonella isolates; one (3.8 %) isolate was resistant while 25 (96.2) isolates were susceptible. No isolate had intermediate susceptibility.
b.) Ampicillin (AMP): Of the 26 salmonella isolates; 24 (92.3%) isolates were resistant while 2 (7.7%) isolates were susceptible. No isolate had intermediate susceptibility.
c.) Cefuroxime (CFX): Of the 26 salmonella isolates; 4 (15.4%) isolates were resistant while 22 (84.6%) isolates shown intermediate susceptibility. No isolate was susceptible.
d.) Ceftriaxone (COX): Of the 26 salmonella isolates; 13 (50.0%) isolates we susceptible, 9 (34.6%) were resistant while 4 (15.4%) isolates shown intermediate susceptibility.
e.) Gentamycin (CEN): Of the 26 salmonella isolates; 25 (96.2%) isolates were susceptible while 1 (3.8%) isolate was resistant. No isolate had intermediate susceptibility.
f.) Imipenem (IMP): Of the 26 salmonella isolates; 25 (96.2%) isolates were susceptible while one (3.8%) isolate had intermediate susceptibility. No isolate was resistant.
g.) Amoxicillin-clavulanic acid (AMC): Of the 26 salmonella isolates; 21 (80.8%) isolates were resistant, four (15.4%) isolates were susceptible while one (3.8%) isolate had intermediate susceptibility.
h.) Tetracycline (TET): Of the 26 salmonella isolates, 23 (88.5%) isolates were susceptible while three (11.5%) isolates were resistant. No isolate had intermediate susceptibility.
i.) Chloramphenicol (COL): Of the 26 salmonella isolates; 19 (73.1%) isolates were susceptible, two (7.7%) isolates were resistant while five (19.2%) isolates had intermediate susceptibility.
j.) Cotrimoxazole (SXT): Of the 26 salmonella isolates; 24 (92.3%) isolates were susceptible while two (7.7%) were resistant. No isolate had intermediate susceptibility.
k.) Nalidixic acid (NAL): Of the 26 salmonella isolates; 11 (42.3%) isolates were susceptible, 11 (42.3%) isolates had intermediate susceptibility while four (15.4%) isolates were resistant.
l.) Ciprofloxacin (CIP): Of the 26 salmonella isolates; 20 (76.9%) isolates were susceptible, one (3.8%) isolate was resistant while five (19.2%) isolates had intermediate susceptibility as shown in figure 3 below.
Factors associated with confirmed Salmonella infection (salmonellosis).
Bi-variate data analysis showed observed association between salmonellosis and;
- Being of female gender, odds ratio (OR) 1.17, confidence interval (95% CI) 0.51 – 2.71, p-value 0.71.
- Having a primary level of education OR 1.57, 95% CI 0.59 – 4.15, p-value 0.37.
- The practice of non-hand washing practice OR 1.45, 95% CI 0.31 – 6.76, p-value 0.64.
- Having a history of gastric surgery OR 1.36, 95% CI 0.27 – 6.82, p-value 0.71.
- Consumption of locally packed water in “kavera” OR 1.28, 95% CI 0.55 – 2.96, p-value 0.57.
- Being on helicobacter pylori treatment OR 1.05, 95% CI 0.41 – 2.71, p-value 0.91 as shown in table 4 below.
Table 4: Factors associated with confirmed Salmonella infection (bi-variate analysis).
Factor
|
Odds ratio
|
p-value
|
95% Confidence interval
|
Gender
Female
|
1.17
|
0.71
|
0.51 - 2.71
|
Education
Primary level
|
1.57
|
0.38
|
0.59 - 4.16
|
Hand wash
No
|
1.45
|
0.64
|
0.31 - 6.76
|
Gastric surgery
Yes
|
1.36
|
0.71
|
0.27 - 6.82
|
Drink Locally packed water (kavera)
Yes
|
1.28
|
0.57
|
0.55 - 2.96
|
Helicobacter pylori treatment
Yes
|
1.05
|
0.91
|
0.41- 2.71
|
Multi-variate data analysis and controlling for confounders using Mantel-Haenszel (MH) method showed a little stronger association between salmonellosis and;
- Consumption of locally packed water in “kavera” MH OR 2.15, 95% CI 0.87 – 5.30, p-value 0.09.
- The practice of non-hand washing practice MH OR 1.76, 95% CI 0.33 – 9.56, p-value 0.50.
- Having a primary level of education MH OR 1.95, 95% CI 0.71 – 5.19, p-value 0.20.
- Having a history of gastric surgery MH OR 1.68, 95% CI 0.29 – 9.67, p-value 0.55.
- Being on helicobacter pylori treatment MH OR 1.28, 95% CI 0.32 – 5.15, p-value 0.73 as shown in table 5 below.
Table 5: Factors associated with confirmed Salmonella infection (multi-variate analysis and mantel-Haenszel analysis).
Factor
|
MH- odds ratio
|
p-value
|
95% confidence interval
|
Locally packed water
Yes
|
2.15
|
0.09
|
0.87 - 5.30
|
Hand washing
No
|
1.76
|
0.50
|
0.33 - 9.56
|
Gastric surgery
Yes
|
1.68
|
0.56
|
0.29 - 9.67
|
Helicobacter pylori treatment
Yes
|
1.28
|
0.73
|
0.32 - 5.15
|
Education
Primary level
|
1.95
|
0.20
|
0.71 - 5.19
|