Isolation and molecular characterization of Bacillus cereus from cow’s raw milk

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dc.contributor.advisorGreen, Een
dc.contributor.advisorOkoh, Anthony Ien
dc.contributor.advisorNdip, R Nen
dc.contributor.authorLukanji, Zinathien
dc.contributor.authorNdip, R Nen
dc.date.accessioned2026-08-12T23:25:39Z
dc.date.available2026-08-12T23:25:39Z
dc.date.issued2015en
dc.description.abstractBacillus cereus is a group of ubiquitous facultative anaerobic spore forming Gram-positive rods commonly found in soil. It has been detected and implicated in several contaminated food products and raw milk in dairy farms and it causes foodborne gastroenteritis by producing several toxins. This study is aimed at characterizing virulence determinants of B. cereus from cow‟s raw milk. A total of 400 raw milk samples were collected in Fort Hare Dairy Trust and Middledrift Dairy Farm; and cultured on Polymyxin pyruvate Egg-Yolk Mannitol Bromothymol Agar (PEMBA) for 48 hours at 37°C. DNA was isolated from the isolates and 16S rDNA was amplified and sent to Central Analytical Laboratory for sequencing. The gyrB gene of B. cereus was also used to confirm the identity of the isolates. Antibiotic susceptibility profiles of the isolates together with virulence genes were investigated. Multilocus Sequence typing was used to investigate the genetic relatedness of some selected isolates. Furthermore, spores of the isolates were produced, harvested and their concentrations determined. All (100%) of the isolates were identified as having a 96-99% similarity to B. cereus, B. thuringiensis and B. anthracis using sequencing; while gyrB gene was observed in all (100%) of the isolates. Three virulence genes nheA, nheB, nheC encoding for non haemolysin enterotoxin were amplified in all (100%) the isolates. All (100%) of the isolates were susceptible to doxycycline, gentamycin, tetracycline, ciprofloxacin, chloramphenicol and streptomycin. Resistance to rifampicin and penicillin G was predominant with equal rate of 100%, while susceptibility to erythromycin, clindamycin and doxycycline ranged from 60% to 100%. The selected isolates were related and are descendants of the same ancestor. All (100%) the isolates produced spores. The B. cereus isolates contain virulence genes, has multiple antibiotic drug resistance and produce spores, which poses a health risk to the public and cannot be used as probiotics.en
dc.format104 leaves; 30 cmen
dc.formatpdfen
dc.identifier.citationLukanji, Zinathi. 2015en
dc.identifier.othervital:11296en
dc.identifier.otherhttp://hdl.handle.net/10353/d1021284en
dc.identifier.otherMilk contamination -- South Africa -- Eastern Capeen
dc.identifier.otherBacillus (Bacteria) -- South Africa -- Eastern Capeen
dc.identifier.otherFoodborne diseases -- Molecular diagnosis -- South Africa -- Eastern Capeen
dc.identifier.otherDairy products -- South Africa -- Eastern Capeen
dc.identifier.urihttp://hdl.handle.net/20.500.11837/4556
dc.language.isoEnglishen
dc.publisherUniversity of Fort Hareen
dc.publisherFaculty of Science & Agricultureen
dc.rightsUniversity of Fort Hareen
dc.subjectMilk contamination -- South Africa -- Eastern Capeen
dc.subjectBacillus (Bacteria) -- South Africa -- Eastern Capeen
dc.subjectFoodborne diseases -- Molecular diagnosis -- South Africa -- Eastern Capeen
dc.subjectDairy products -- South Africa -- Eastern Capeen
dc.titleIsolation and molecular characterization of Bacillus cereus from cow’s raw milken
dc.title.alternativeIsolation and molecular characterization of Bacillus cereus from cow’s raw milken
dc.typeThesisen
dc.typeMastersen
dc.typeMSc (Microbiology)en

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