Prevalence and antibiotic susceptibility of &lt;i&gt;Salmonella enterica&lt;/i&gt; isolated from cow milk, milk products and hands of sellers in the Tamale Metropolis of Ghana

F Adzitey,E.F Boateng,P Asiamah

doi:10.4314/jasem.v24i1.8

Abstract

Salmonella enterica are among the foodborne pathogens of importance due to their involvement in a number of foodborne outbreaks, illnesses and occasionally death. This study was carried out in the Tamale metropolis of Ghana to investigate the prevalence and antibiotic resistance of Salmonella enterica in cow milk, cow milk products and hands of cow milk sellers. The conventional method and the disc diffusion method were used for the isolation and antibiotic resistance of Salmonella enterica, respectively. The overall prevalence of Salmonella enterica was 7.3% (22/300). Salmonella enterica were detected in 24.0% (12/50) of raw ‘wagashie’, 8.0% (4/50) of fried ‘wagashie’, 6.0% (3/50) of cow milk, 4.0% (2/50) of left hand swab of milk sellers, and 2.0% (1/50) of right hand swab of milk sellers. Salmonella enterica was not isolated from ‘brukina’. The prevalence of Salmonella enterica did not differ (P = 0.193) among fried ‘wagashie’, cow milk, hand swab of milk sellers and ‘brukina’ samples. However, the prevalence of Salmonella enterica in raw ‘wagashie’ was significantly higher (P = 0.000) than the other samples examined. Resistant to erythromycin (86.0%) was most frequently detected. The Salmonella enterica isolates were highly susceptible to ciprofloxacin (100.0%), chloramphenicol (91.0%), ceftriaxone (91.0%), sulphamethoxazole/trimethoprim (91.0%), tetracycline (86.0%) and ampicillin (86.0%). Of the 22 Salmonella enterica isolates, 14 were resistant to only one antibiotic, 4 were resistant to two antibiotics and 2 were resistant to three antibiotics. Two Salmonella enterica isolates were resistant to none of the antibiotics. This study revealed that some milk products and other samples were contaminated with Salmonella enterica. The isolated Salmonella enterica were susceptible to most of the antibiotics examined but were highly resistant to erythromycin.Keywords: Antimicrobials, Foodborne pathogens, Food safety, Milk, Milk products

Highlights

MATERIALS AND METHODSStudy area: This study was conducted in the Tamale metropolis. Tamale is the capital town of the Northern region of Ghana
Milk and milk products constitute important nutritional components of human diets and play prominent roles in human nutrition (Medhammar et al, 2012)
Outbreaks of milk-borne diseases have occurred despite pasteurization caused either by improper pasteurization or recontamination thereby posing some risks to consumers (DeSilva et al, 2001)

Summary

MATERIALS AND METHODS

Study area: This study was conducted in the Tamale metropolis. Tamale is the capital town of the Northern region of Ghana. The city lies between latitude 9o16 and 9o34 North and longitudes 0o36 and 0o57 West (GSS, 2010). Isolated Salmonella enterica were subjected to antimicrobial susceptibility test to determine their resistances. Samples were pre-enriched in buffered peptone water (BPW) and incubated at 37°C for 18 24hours. These were the ratios for the samples; 10ml of milk sample: 90ml of BPW, 10g of ‘wagashie’ (fried and raw): 90ml of BPW, 10ml of ‘brukina’: 90ml of BPW, and 1 swab of hand (left and right, 10cm2): 10ml of BPW. Pure Salmonella enterica isolates were grown in tryptic soy broth (TSB) (Oxoid, UK) at 37oC for 16 to 24 hours and the concentration adjusted using sterile TSB until 0.5 McFarland turbidity was attained. Test for statistical difference was done using wald chi-square at 5% significance level

RESULTS AND DISCUSSION

22 Fried ‘wagashie’ EAmpCn 3

Conclusions