title: Prevalence, virulence factor genes and antibiotic resistance of Bacillus cereus sensu lato isolated from dairy farms and traditional dairy products.
abstract: B. cereus are of particular interest in food safety and public health because of their capacity to cause food spoilage and disease through the production of various toxins. The aim of this study was to determine the prevalence, virulence factor genes and antibiotic resistance profile of B. cereus sensu lato isolated from cattle grazing soils and dairy products in Ghana. A total of 114 samples made up of 25 soil collected from cattle grazing farm land, 30 raw milk, 28 nunu (yoghurt-like product) and 31 woagashie (West African soft cheese). Ninety-six B. cereus sensu lato isolates from 54 positive samples were screened by PCR for the presence of 8 enterotoxigenic genes (hblA, hblC, hblD, nheA, nheB, nheC, cytK and entFM), and one emetic gene (ces). Phenotypic resistance to 15 antibiotics were also determined for 96 B. cereus sensu lato isolates.
  
  
  
  About 72% (18 of 25 soil), 47% (14 of 30 raw milk), 35% (10 of 28 nunu) and 39% (12 of 31 woagashi) were positive for B. cereus sensu lato with mean counts (log10cfu/g) of 4.2 ± 1.8, 3.3 ± 2.0, 1.8 ± 1.4 and 2.6 ± 1.8 respectively. The distribution of enterotoxigenic genes revealed that 13% (12/96 isolates) harboured all three gene encoding for haemolytic enterotoxin HBL complex genes (hblA, hblC and hblD), 25% (24/96 isolates) possessed no HBL gene, whereas 63% (60/96 isolates) possessed at least one of the three HBL genes. All three genes encoding for non-haemolytic enterotoxin (nheA, nheB and nheC) were detected in 60% (57/96) isolates, 14% (13/96) harboured only one gene, 19% (18/96) whereas 8% possessed none of the NHE genes. The detection rates of cytk, entFM, and ces genes were 75, 67 and 9% respectively. Bacillus cereus s. l. isolates were generally resistant to β-lactam antibiotics such as ampicillin (98%), oxacillin (92%), penicillin (100%), amoxicillin (100%), and cefepime (100%) but susceptible to other antibiotics tested.
  
  
  
  Bacillus cereus s. l. is prevalent in soil, raw milk and dairy products in Ghana. However, loads are at levels considered to be safe for consumption. Various enterotoxin genes associated with virulence of B. cereus are widespread among the isolates.
authors.affiliation: Department of Applied Biology, Faculty of Applied Sciences, University for Development Studies, P. O. Box 24,, Navrongo campus, Navrongo, Ghana. jowusukwarteng@uds.edu.gh.
authors.forename: James
authors.initials: J
authors.lastname: Owusu-Kwarteng
authors.affiliation: Department of Biotechnology, Faculty of Agriculture, University for Development Studies, Nyankpala, Tamale, Ghana.
authors.forename: Alhassan
authors.initials: A
authors.lastname: Wuni
authors.affiliation: Department of Applied Biology, Faculty of Applied Sciences, University for Development Studies, P. O. Box 24,, Navrongo campus, Navrongo, Ghana.
authors.forename: Fortune
authors.initials: F
authors.lastname: Akabanda
authors.affiliation: Department of Nutrition and Food Science, Faculty of Science, University of Ghana, Legon, Accra, Ghana.
authors.forename: Kwaku
authors.initials: K
authors.lastname: Tano-Debrah
authors.affiliation: Department of Food Science, University of Copenhagen, Rolighedsvej 26, DK 1958, Frederiksberg C, Denmark.
authors.forename: Lene
authors.initials: L
authors.lastname: Jespersen
mesh_terms: D000818:Animals; D001409:Bacillus cereus / Q000235:genetics* / Q000302:isolation & purification*; D002417:Cattle; D004269:DNA, Bacterial / Q000235:genetics; D003611:Dairy Products / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004768:Enterotoxins / Q000235:genetics; D000072480:Farms; D005516:Food Microbiology; D059022:Food Safety; D005798:Genes, Bacterial / Q000235:genetics; D005869:Ghana; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012988:Soil Microbiology; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D004768:Enterotoxins; D037521:Virulence Factors
keywords: Antibiotic resistance; Bacillus cereus sensu lato; Dairy product; Emetic toxin gene; Enterotoxin; Virulence gene