<p>Molecular Detection Of Multidrug-Resistant <em>Salmonella</em> Isolated From Livestock Production Systems In South Africa</p>

Abstract

Background: 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. Methods: 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. Results: Most of the isolates were resistant to ampicillin (64%), tetracycline (63%), amoxicillinclavulanate (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. Conclusion: 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.

Antimicrobial Resistance Profile andmcr-1Gene Detection inSalmonellaIsolates from Poultry in Bangladesh: Molecular and Bioinformatics Characterization

“…The present study represented that, 100% of the mcr-1 positive isolates were MDR. Similar findings were reported on MDR in Salmonella isolates from Bangladesh and different parts of the world (29, 67–72). Due to the indiscriminate victimization of antimicrobial agents, MDR strains may apparently be occurred with high incidence in this area which is a serious concern for veterinary medicine and also for human health since direct transmission of resistant isolates from animals to humans has been confirmed (73).…”

Antimicrobial Resistance Profiles of Salmonella Isolates on Chickens Processed and Retailed at Outlets of the Informal Market in Gauteng Province, South Africa

“…Equally of potential therapeutic importance was the detection of a very high (94.0%) prevalence of MDR isolates of Salmonella. Other studies of the pathogens of poultry in South Africa have similarly reported a high prevalence of MDR in Salmonella isolates in chickens and other livestock, thus highlighting their therapeutic and public health implications [ 42 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. The prevalence of MDR in the current study is higher than was reported, also using the disc diffusion method, for Salmonella from chickens (caeca) in Trinidad, 14.3% [ 46 ], Portugal, 75.0% [ 57 ], China, 80.0% [ 58 ], and in the USA, 92.0% [ 59 ], but lower than that reported for isolates in Nepal, 100% [ 60 ], Mauritius, 100% [ 61 ] and Trinidad, 100.0% [ 41 ] and globally [ 34 ].…”

Antimicrobial Usage Factors and Resistance Profiles of Shiga Toxin-Producing Escherichia coli in Backyard Production Systems From Central Chile

“…These production systems have been linked to the occurrence of several zoonotic and non-zoonotic outbreaks worldwide ( 11 , 14 , 15 , 64 ). BPS maintain a wide spectrum of species that harbor STEC, including cattle ( 22 ), sheep and goats ( 23 , 65 ), and poultry and captive wild birds ( 11 , 24 ). Positivity reported by this study (11.76%) is similar to what has been reported in productive animal species (cattle and swine) under industrialized conditions in Chile ( 7 ).…”