Digital Knowledge Collection:

Chryseobacterium carnipullorum sp. nov., isolated from raw chicken

2018-11-05T13:41:40Z

Title: Chryseobacterium carnipullorum sp. nov., isolated from raw chicken Authors: Charimba, George; Jooste, P; Albertyn, J; Hugo, C Abstract: Three Gram-staining-negative, rod-shaped, non-spore-forming, non-motile, oxidase-positive, yellow pigmented and aerobic bacterial isolates designated 8_R23573, 9_R23581T and 10_R23577 were isolated from raw chicken at a broiler processing plant in Bloemfontein, South Africa. A polyphasic taxonomic approach was used to determine their exact taxonomic identities. Phylogenetic analysis of the 16S rRNA gene sequences showed that the three strains belonged to the genus Chryseobacterium, exhibiting the highest similarities to Chryseobacterium shigense DSM 17126T (98.6-99.2 %) and Chryseobacterium luteum DSM 18605T (98.3-98.7 %). The most abundant quinone was menaquinone MK-6 and the predominant cellular fatty acids were iso-15: 0, iso-17: 1 ω9c, iso-17: 0 3-OH and summed feature 3 (iso-16: 1 ω7c and/or iso-15: 0 2-OH), which supported the affiliation of the strains to the genus Chryseobacterium. The DNA G + C contents of the strains were 36.9, 36.7 and 36.6 mol% respectively. The DNA-DNA hybridization results gave relatedness values ranging from 78.8 to 87.2 % among the three strains and 23.4 to 56.1 % to the two nearest phylogenetic neighbours C. shigense DSM 17126T and C. luteum LMG 23785T. On the basis of the data from this polyphasic study, the three strains are concluded to represent a novel species of the genus Chryseobacterium for which the name Chryseobacterium carnipullorum sp. nov. is proposed. The type strain is 9_R23581T (=LMG 26732T=DSM 25581T).

Characterization of bacterial pathogens in rural and urban irrigation water

2018-11-05T13:41:26Z

Title: Characterization of bacterial pathogens in rural and urban irrigation water Authors: Aijuka, M; Charimba, George; Hugo, CJ; Buys, Elna. M Abstract: The study aimed to compare the bacteriological quality of an urban and rural irrigation water source. Bacterial counts, characterization, identification and diversity of aerobic bacteria were determined. Escherichia coli isolated from both sites was subjected to antibiotic susceptibility testing, virulence gene (Stx1/Stx2 and eae) determination and (GTG)5 Rep-PCR fingerprinting. Low mean monthly counts for aerobic spore formers, anaerobic spore formers and Staphylococcus aureus were noted although occasional spikes were observed. The most prevalent bacterial species at both sites were Bacillus spp., E. coli and Enterobacter spp. In addition, E. coli and Bacillus spp. were most prevalent in winter and summer respectively. Resistance to at least one antibiotic was 84% (rural) and 83% (urban). Highest resistance at both sites was to cephalothin and ampicillin. Prevalence of E. coli possessing at least one virulence gene (Stx1/Stx2 and eae) was 15% (rural) and 42% (urban). All (rural) and 80% (urban) of E. coli possessing virulence genes showed antibiotic resistance. Complete genetic relatedness (100%) was shown by 47% of rural and 67% of urban E. coli isolates. Results from this study show that surface irrigation water sources regardless of geographical location and surrounding land-use practices can be reservoirs of similar bacterial pathogens

The incidence of diarrhoeagenic escherichia coli in minced beef and boerewors

2018-06-09T08:45:34Z

Title: The incidence of diarrhoeagenic escherichia coli in minced beef and boerewors Authors: Charimba, George; Hugo, C; Hugo, A Abstract: A survey of diarrhoeagenic Escherichia coli (DEC) was carried out on 21 minced beef and 21 boerewor (a traditional South African fresh sausage) samples purchased from 30% of butcheries in the Bloemfontein District of South Africa. The samples were cultivated on standard plate count agar for aerobic plate counts and chromocult coliform agar for coliform and E. coli counts without enrichment. Diarrhoeagenic E. coli were isolated after enrichment in MacConkey broth followed by cultivation on chromocult coliform agar. The resultant E. coli colonies were selected and serotyped using the slide agglutination test for DEC. Eight (38.10%) minced beef samples were positive for DEC. The 8 positive samples consisted of 5 (23.81%) EPEC and 1 each (4.76%) of EIEC, EAggEC, and VTEC. A total of 100 isolates were serotyped (5 from each sample) and these comprised 6 (6%) EPEC serotypes (3×O18; 1×O125; and 1×O142), and 1 (1%) each of EIEC (1×O128 ac), EAggEC (1×O44) and VTEC (1×O26). Boerewors had 6 (28.57%) samples that were positive for DEC. EPEC and VTEC were the virotypes that were isolated at 23.81% (5/21) and 4.76% (1/21) respectively. A total of 105 isolates were serotyped (5 from each sample) and these comprised 7 (6.66%) EPEC (3×O18, 2×O125, 1×O55 and 1×O142); and 1 (0.95%) VTEC (1×O26). EPEC were the most frequent virotype while VTEC were the most virulent virotype recovered from both products. No E. coli O157:H7 were recovered.

In vitro antimicrobial activities of Bidens pilosa and Moringa oleifera leaf extracts and their effects on ground beef quality during cold storage

2017-12-11T21:50:31Z

Title: In vitro antimicrobial activities of Bidens pilosa and Moringa oleifera leaf extracts and their effects on ground beef quality during cold storage Authors: Falowo, AB; Muchenje, V; Hugo, CJ; Charimba, George Abstract: This study determined the activities of Bidens pilosa and Moringa oleifera leaf extracts on microbial count of ground beef during 6-day cold storage. Fresh ground beef sample was treated with butylated hydroxytoluene (BHT) (0.2 g/kg), M. oleifera (ML, 1 g/kg) and B. pilosa (BP, 1 g/kg) leaf extracts and compared with the control. The result of the phytochemical contents revealed that ML extract had higher phenolic and flavonoid contents than BP extract (p > 0.05). The antibacterial assay of the extracts revealed an appreciable broad-spectrum activity against tested bacteria with minimum inhibitory concentrations between 0.6 and 10.0 mg/mL. Addition of ML leaf extract to ground beef sample lowered total viable and lactic acid bacteria (p < 0.05) counts than control and BHT treatments at day 3 of storage. These results suggest that ML leaf extract could be used as potential sources of natural antimicrobial agent in meat products