+1 Recommend
0 collections
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Molecular Detection Of Multidrug-Resistant Salmonella Isolated From Livestock Production Systems In South Africa

      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.



          Antibiotic-resistant bacterial pathogens associated with livestock remain a major concern worldwide as they get transmitted from animals to humans and cause foodborne and zoonotic diseases.


          Antimicrobial resistance in livestock-associated Salmonella spp in South Africa was investigated using molecular DNA methods. Three hundred and sixty-one environmental faecal samples were randomly collected from avian (chicken and ducks), cows, pigs, goats, and sheep. Salmonella spp. were isolated on selective media and were confirmed using the polymerase chain reaction. Antimicrobial susceptibility testing against ampicillin, chloramphenicol, ciprofloxacin, ceftriaxone, azithromycin, tetracycline, amoxicillin-clavulanate and trimethoprim-sulfamethoxazole was determined using the Kirby–Bauer disk diffusion method. Isolates were screened for the presence of bla TEM-1, bla CMY-2, tetA, tetC, sul2 and dfrA7 resistance genes by PCR.


          Most of the isolates were resistant to ampicillin (64%), tetracycline (63%), amoxicillin-clavulanate (49%), trimethoprim-sulfamethoxazole (38%), and ceftriaxone (20%). Eight percent of the tested isolates were ciprofloxacin-resistant Salmonella spp. Multidrug resistance was observed with the mean multiple antibiotic resistance (MAR) index of 0.31. The study demonstrated that 43% of the isolates were multiple drug resistant. The prevalence rates of resistance genes were 44% for bla TEM-1 , 35% for bla CMY-2 , 21% for sul2, 18% for tetC, 14% for dfrA7 and 8% for tetA.


          Resistance to ceftriaxone, detection of bla CMY-2 gene and the high level of intermediate susceptibility (33%) against ciprofloxacin suggested that livestock carry problematic Salmonella spp. This study used the global one-health initiative to report the potential public health risks of livestock-associated pathogens and highlights the importance of monitoring the trends of antimicrobial resistance for sustainability of antibiotics.

          Related collections

          Most cited references 61

          • Record: found
          • Abstract: found
          • Article: not found

          Outer membrane permeability and antibiotic resistance.

          To date most antibiotics are targeted at intracellular processes, and must be able to penetrate the bacterial cell envelope. In particular, the outer membrane of gram-negative bacteria provides a formidable barrier that must be overcome. There are essentially two pathways that antibiotics can take through the outer membrane: a lipid-mediated pathway for hydrophobic antibiotics, and general diffusion porins for hydrophilic antibiotics. The lipid and protein compositions of the outer membrane have a strong impact on the sensitivity of bacteria to many types of antibiotics, and drug resistance involving modifications of these macromolecules is common. This review will describe the molecular mechanisms for permeation of antibiotics through the outer membrane, and the strategies that bacteria have deployed to resist antibiotics by modifications of these pathways.
            • Record: found
            • Abstract: found
            • Article: not found

            Multiple antibiotic resistance indexing of Escherichia coli to identify high-risk sources of fecal contamination of foods.

             P Krumperman (1983)
            Escherichia coli isolates taken from environments considered to have low and high enteric disease potential for humans were screened against 12 antibiotics to determine the prevalence of multiple antibiotic resistance among the isolates of these environments. It was determined that multiple-antibiotic-resistant E. coli organisms exist in large numbers within the major reservoirs of enteric diseases for humans while existing in comparatively low numbers elsewhere. These differences provide a method for distinguishing high-risk contamination of foods by indexing the frequency with which multiple-antibiotic-resistant E. coli organisms occur among isolates taken from a sample.
              • Record: found
              • Abstract: found
              • Article: not found

              Does the use of antibiotics in food animals pose a risk to human health? A critical review of published data.

              The use of antibiotics in food animals selects for bacteria resistant to antibiotics used in humans, and these might spread via the food to humans and cause human infection, hence the banning of growth-promoters. The actual danger seems small, and there might be disadvantages to human and to animal health. The low dosages used for growth promotion are an unquantified hazard. Although some antibiotics are used both in animals and humans, most of the resistance problem in humans has arisen from human use. Resistance can be selected in food animals, and resistant bacteria can contaminate animal-derived food, but adequate cooking destroys them. How often they colonize the human gut, and transfer resistance genes is not known. In zoonotic salmonellosis, resistance may arise in animals or humans, but human cross-infection is common. The case of campylobacter infection is less clear. The normal human faecal flora can contain resistant enterococci, but indistinguishable strains in animals and man are uncommon, possibly because most animal enterococci do not establish themselves in the human intestine. There is no correlation between the carriage of resistant enterococci of possible animal origin and human infection with resistant strains. Commensal Escherichia coli also exhibits host-animal preferences. Anti-Gram-positive growth promoters would be expected to have little effect on most Gram-negative organisms. Even if resistant pathogens do reach man, the clinical consequences of resistance may be small. The application of the 'precautionary principle' is a non-scientific approach that assumes that risk assessments will be carried out.

                Author and article information

                Infect Drug Resist
                Infect Drug Resist
                Infection and Drug Resistance
                14 November 2019
                : 12
                : 3537-3548
                [1 ]School of Life Sciences, University of KwaZulu-Natal , Durban, 4000, South Africa
                [2 ]Virology and Microbiology Research Group, School of Health Sciences, University of KwaZulu-Natal , Durban, 4000, South Africa
                [3 ]Infectious Diseases and Anti-Infective Research Group, College of Pharmacy, University of Sharjah , Sharjah, 27272, UAE
                Author notes
                Correspondence: Mohamed E El Zowalaty Department of Pharmacy, City University College of Ajman , Ajman18484, UAE Email elzow001@gmail.com
                © 2019 Mthembu et al.

                This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License ( http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms ( https://www.dovepress.com/terms.php).

                Page count
                Figures: 3, Tables: 7, References: 78, Pages: 12
                Original Research


                Comment on this article