Distribution of virulence factors, determinants of antibiotic resistance and molecular fingerprinting of Salmonella species isolated from cattle and beef samples: suggestive evidence of animal-to-meat contamination
In this study, three hundred presumptive Salmonella strains isolated from cattle faeces and raw beef samples were subjected to both preliminary and confirmatory tests specific for Salmonella. PCR assays revealed that 100%, 20% and 26.7% of the isolates were positive for 16S rRNA, fliC and fljB gene fragments, respectively. Large proportions (62.4 to 94.3%) of these isolates were multiple antibiotic resistant (MAR) strains that were resistant to three or more antibiotics belonging to different classes. MAR phenotypes Ab1, Ab2, Ab3, Ab7, Ab8, Ab9, Ab26 and Ab27 were dominant among the isolates. Cluster analysis of antibiotic inhibition zone diameter data revealed two major clusters (clusters 1 and 2), and each cluster contained two sub-clusters (1A, 1B, 2A and 2B). PCR data revealed that 27.1% and 30.7% of the isolates possessed the spvC and invA virulent genes, respectively. There was a significant correlation between the possession of MAR phenotypes and virulent gene determinants. Analysis of restriction fragment length polymorphism (RFLP) of 16S rRNA gene fragments using EcoRI and HaeIII showed that large proportions of isolates from beef and cattle faeces produced similar genetic fingerprints. From these results, it is suggested that Salmonella species in cattle are transmitted to beef and, therefore, the consumption of undercooked beef could pose severe health complications on consumers. These findings provide baseline data that could be of great epidemiological importance and, thus, the need to utilise more sensitive typing tools in determining the genetic relatedness of isolates from different sources.
KeywordsAntibiotic resistance 16S rRNA gene fljB gene fliC gene RFLP Salmonella Virulence genes (spvC and invA)
This study was supported by the North-West University, Mafikeng Campus, South Africa. We are grateful to the National Research Foundation for the postgraduate bursary that was awarded to Mr. SB Dlamini. We also wish to thank Mr. BJ Morapedi for his assistance during the collection of samples.
Compliance with ethical standards
Application for ethical clearance for this study was requested and obtained from the Mafikeng Animal Research Ethics Committee (MAREC), North-West University, and ethics approval with ID (NWU-00066-15-S9) was granted for the research to be conducted.
Conflict of interest
The authors declare that they have no conflict of interest.
- Abatcha M, Zakaria Z, Kaur D, Thong K (2014) Review article: a trends of Salmonella and antibiotic resistance. Adv Life Sci Technol 17:9–21Google Scholar
- Abdullahi M (2010) Incidence and antimicrobial susceptibility pattern of Salmonella species in children attending some hospitals in Kano Metropolis, Kano State-Nigeria. Bayero J Pure Appl Sci 3:202–206Google Scholar
- Amini K, Salehi TZ, Nikbakht G, Ranjbar R, Amini J, Ashrafganjooei SB (2010) Molecular detection of invA and spv virulence genes in Salmonella enteritidis isolated from human and animals in Iran. Afr J Microbiol Res 4:2202–2210Google Scholar
- Andino AM, Hanning I (2015) Salmonella enterica: survival, colonization, and virulence differences among serovars. Sci World J Article ID 520179, 16 pagesGoogle Scholar
- Angulo FJ, Collignon P, Powers JH, Chiller TM, Aidara-Kane A, Aarestrup FM (2009) World Health Organization ranking of antimicrobials according to their importance in human medicine: a critical step for developing risk management strategies for the use of antimicrobials in food production animals. Clin Infect Dis 49:132–141CrossRefGoogle Scholar
- Barrett EL, Clark MA (1987) Tetrathionate reduction and production of hydrogen sulfide from thiosulfate. Microbiol Rev 51:192Google Scholar
- Biran A, Curtis V, Gautam OP, Greenland K., Islam S, Schmidt WP, Sijbesma C, Sumpter C, Torondel B (2012). Background paper on measuring Wash and food hygiene practices–definition of goals to be tackled post 2015 by the Joint Monitoring Program. London School of Hygiene and Tropical Medicine, Dept. of Public Health and Polic, London, p 81Google Scholar
- Cardinale E, Perrier Gros-Claude J, Rivoal K, Rose V, Tall F, Mead G, Salvat G (2005) Epidemiological analysis of Salmonella enterica ssp. enterica serovars hadar, brancaster and enteritidis from humans and broiler chickens in Senegal using pulsed-field gel electrophoresis and antibiotic susceptibility. J Appl Microbiol 99:968–977CrossRefGoogle Scholar
- Chiu CH, Ou JT (1996) Rapid identification of Salmonella serovars in feces by specific detection of virulence genes, invA and spvC, by an enrichment broth culture-multiplex PCR combination assay. J Clin Microbiol 34:2619–2622Google Scholar
- CLSI (2012) Performance standards for antimicrobial susceptibility testing: twenty-second informational supplement. CLSI document M100-S22. Wyane, PA. provides updated tables for M02-A11 and M07-A9. Clinical Laboratory Standards InstituteGoogle Scholar
- Dauga C, Zabrovskaia A, Grimont PA (1998) Restriction fragment length polymorphism analysis of some flagellin genes of Salmonella enterica. J Clin Microbiol 36:2835–2843Google Scholar
- Jadidi A, Hosseni SD, Homayounimehr A, Hamidi A, Ghani S, Rafiee B (2012) Simple and rapid detection of Salmonella sp. from cattle feces using polymerase chain reaction (PCR) in Iran. Afr J Microbiol Res 6:5210–5214Google Scholar
- Matias CAR, Pereira IA, de Araujo MS, Santos AFM, Lopes RP, Christakis S, Rodrigues DP, Siciliano S (2016) Characteristics of Salmonella spp. isolated from wild birds confiscated in illegal trade markets, Rio de Janeiro, Brazil. BioMed Res Int Article ID 3416864, 7Google Scholar
- Molla B, Alemayehu D, Salah W (2003) Sources and distribution of Salmonella serotypes isolated from food animals, slaughterhouse personnel and retail meat products in Ethiopia: 1997-2002. Ethiop J Heal Dev 17:63–70Google Scholar
- National Institute for Communicable Disease (NICD) (2018) Listeriosis situation report. Department of Health, 11th June 2018. (http://www.nicd.ac.za/)
- Rocourt J, Moy G, Vierk K, Schlundt J (2003) The present state of foodborne disease in OECD countries. WHO, GenevaGoogle Scholar
- Saeed AA, Hasoon MF, Mohammed MH (2013) Isolation and molecular identification of Salmonella typhimurium from chicken meat in Iraq. J World’s Poult Res 3:63–67Google Scholar
- Sperber W, Deibel R (1969) Accelerated procedure for Salmonella detection in dried foods and feeds involving only broth cultures and serological reactions. Appl Microbiol 17:533–539Google Scholar
- Su L, Chiu C (2007) Salmonella: clinical importance and evolution of nomenclature. Chang Gung Med J 30:210Google Scholar
- Zahran R, El-Behiry A (2014) Prevalence, molecular identification and virulence attributes of Salmonella serovars isolated from feces of diarrheic cow and buffalo-calves. Int J Curr Microbiol App Sci 3:9–27Google Scholar
- Zamxaka M, Pironcheva G, Muyima N (2004) Microbiological and physico-chemical assessment of the quality of domestic water sources in selected rural communities of the Eastern Cape Province, South Africa. Water SA 30:333–340Google Scholar