RESUMEN
As poultry organ meat is widely consumed, especially in low- and middle-income countries, there is reason to investigate it as a source of Salmonella infections in humans. Consequently, the aim of this study was to determine the prevalence, serotypes, virulence factors and antimicrobial resistance of Salmonella isolated from chicken offal from retail outlets in KwaZulu-Natal, South Africa. Samples (n = 446) were cultured for the detection of Salmonella using ISO 6579-1:2017. Presumptive Salmonella were confirmed using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry. Salmonella isolates were serotyped using the Kauffmann-White-Le Minor scheme and antimicrobial susceptibility was determined by the Kirby-Bauer disk diffusion technique. A conventional PCR was used for the detection of Salmonella invA, agfA, lpfA and sivH virulence genes. Of the 446 offal samples, 13 tested positive for Salmonella (2.91%; CI = 1.6-5). The serovars included S. Enteritidis (n = 3/13), S. Mbandaka (n = 1/13), S. Infantis (n = 3/13), S. Heidelberg (n = 5/13) and S. Typhimurium (n = 1/13). Antimicrobial resistance against amoxicillin, kanamycin, chloramphenicol and oxytetracycline was found only in S. Typhimurium and S. Mbandaka. All 13 Salmonella isolates harboured invA, agfA, lpfA and sivH virulence genes. The results show low Salmonella prevalence from chicken offal. However, most serovars are known zoonotic pathogens, and multi-drug resistance was observed in some isolates. Consequently, chicken offal products need to be treated with caution to avoid zoonotic Salmonella infections.
RESUMEN
Annually, approximately 23,000 cases of food poisoning by Staphylococcus aureus enterotoxins are reported worldwide. The aim of this study was to determine the occurrence and characterize S. aureus on beef and beef products in South Africa. Organ meats (n = 169), raw processed meat (n = 110), raw intact (n = 53), and ready-to-eat meats (n = 68) were obtained from 25 retail outlets. S. aureus was isolated and enumerated according to the ISO 6888-1 method. Identification of the strains was performed by MALDI-TOF MS. The antimicrobial resistance was determined using the disc diffusion test. The presence of methicillin-resistance genes and the staphylococcal enterotoxin genes was determined by PCR. Prevalence was low (13/400; CI 1.7-5) and all but one positive sample were from organ meats. Eight isolates were resistant to at least one antibiotic. Two isolates carried the mecC gene. All the isolates tested positive for seg, seh, sei, and sep, whilst 53.8% were positive for sea. None of the isolates was positive for ser, sej, seb, sec, or sed. The prevalence of S. aureus was low, with organ meats being the most contaminated. The presence of mecC-positive MRSA and of enterotoxins warrants further investigation and risk assessment.
RESUMEN
A variety of flocculants have been used to aggregate colloidal substances. However, recently, owing to the adverse effects and high costs of conventional flocculants, natural flocculants such as microbial flocculants are gaining attention. The aim of the study was to produce and characterize a bioflocculant from Pichia kudriavzevii MH545928.1 and apply it in wastewater treatment. A mixture of butanol and chloroform (5:2 v/v) was used to extract the bioflocculant. Phenol-sulphuric acid, Bradford and Carbazole assays were utilized for the identification of carbohydrates, proteins and uronic acid, respectively. Scanning electron microscopy (SEM) and elemental detector were employed to determine the surface morphology and elemental compositions. The removal efficiencies were 73%, 49% and 47% for BOD, COD and P, respectively. The bioflocculant (2.836 g/L) obtained showed the presence of carbohydrates (69%), protein (11%) and uronic acid (16%). The bioflocculant displayed a cumulus-like structure and the elemental composition of C (16.92%), N (1.03%), O (43:76%), Na (0.18%), Mg (0.40%), Al (0.80%), P (14.44%), S (1.48%), Cl (0.31%), K (0.34%) and Ca (20.35). It showed the removal efficiencies of 43% (COD), 64% (BOD), 73% (P) and 50% (N) in coal mine wastewater. This bioflocculant is potentially viable to be used in wastewater treatment.