Listeria monocytogenes is a gram-positive food-borne pathogen that causes listeriosis in humans. Currently, there is little information on the prevalence of
Listeria monocytogenes in raw milk and traditional yoghurt-like milk beverage, nunu, in Ghana. The purpose of this study was to investigate the
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Listeria monocytogenes is a gram-positive food-borne pathogen that causes listeriosis in humans. Currently, there is little information on the prevalence of
Listeria monocytogenes in raw milk and traditional yoghurt-like milk beverage, nunu, in Ghana. The purpose of this study was to investigate the prevalence of
L. monocytogenes isolates in raw cow milk, boiled milk and nunu in Ghana, and to characterize these
L. monocytogenes isolates according to their serogroups, virulence potentials and antibiotic susceptibility profiles. A total of 254 samples comprising 114 raw cow milk, 56 boiled milk and 84 nunu were collected from dairy farms and market vendors for detection of
L. monocytogenes. The overall prevalence of
L. monocytogenes in raw milk, boiled milk and nunu was 5.5% (14/254).
Listeria monocytogenes was prevalent in raw cow milk (8.8%; 10/114) and nunu (13.1%; 11/84), while no
Listeria spp. was not detected in boiled milk. A total of 62
L. monocytogenes isolates were analysed to belong to molecular serogroups 1/2a-3a (32/62, 51.6%), 1/2b-3b-7 (14/62, 22.6%), 4b-4d-4e (9/62, 14.5%) and 1/2c-3c (7/62, 11.3%). All 62
L. monocytogenes isolates harbored the virulence-associated genes
inlA,
inlB,
inlC,
inlJ,
plcA,
actA,
hlyA,
iap and
prfA. All
Listeria monocytogenes in the present study were generally susceptible to the tested antibiotics, except neomycin and tetracycline, for which phenotypic resistance was observed among isolates.
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