Antimicrobial‐resistant genes associated with Salmonella spp. isolated from human, poultry, and seafood sources

Abstract

Antimicrobial-resistant salmonellosis is a significant public health concern globally. A study was conducted to screen for Salmonella species from a total of 120 samples, of which 50 were retail meat samples purchased from five randomly selected sales outlets in the city of Mangalore, India. Twenty poultry fecal materials freshly voided before slaughter were obtained with sterile spatula and placed in sterile sealable polythene envelopes, and 20 clams were purchased from the estuaries of Nethravathi and Kankarnady market. In addition, 30 clinical isolates from Nigeria suspected to be Salmonella by only cultural characterization were also included in the study. In all, 30 samples—6 poultry, 8 seafood, and 16 Salmonella isolates from clinical samples—were confirmed positive by PCR and used in this study. The disk-diffusion test was performed to determine the zone of inhibition, and detection of resistance genes was tested by PCR targeting various antimicrobial genes. Resistance to tetracycline (TET), cotrimoxazole, nalidixic acid, nitrofurantion, and piperacillin/tazobactin was found in 66.7%, 60%, 53.3%, 50% and 50% of the isolates, respectively. About 60–100% of MDR isolates possessed antibiotic-resistant genes, of the tetracyclines resistant isolates, 20 (100%) 6 (30%), 7 (35%), and 10 (50%) carried tetA, tetB, tetC, and tetG genes, respectively. Of 18 cotrimoxazole-resistant strains, 18 (100%), 14 (77.7%), and 4 (22.2%) had sul1, sul2, and sul3 genes, respectively. Of the 14 multidrug-resistant isolates tested, 8 (61%) and 9 (69%) were positive for cmlA and cmlB genes, respectively, 10 (1.4%) tested positive for aph(3)11a genes, 8 (57%) tested positive for aac(3)lla, while none was positive for the aac6 gene. The results show the presence of antibiotic-resistant Salmonella spp. in food samples from India and in human samples from Nigeria.

Antimicrobial susceptibility and MLVA analysis of S. Typhimurium strains isolated from human and poultry samples in Tunisia

“…The S. Typhimurium exhibited high rates of resistance to traditional antibiotics such as ampicillin, nalidixic acid, tetracycline and sulfamethoxazole-trimethoprim; this is in accordance with the findings of other authors [35,36]. The detection of antimicrobial genes and a strict policy for the rational use of antibiotics for treating animals and humans is needed, if we do not want to have to limit the therapeutical choices for treating salmonellosis [5].…”

“…Multidrug-resistant (MDR) Salmonella strains have been among the major public health concerns worldwide [4]. Subsequent transmission of antimicrobial resistance to humans can be in the form of either resistant pathogens or commensal organisms carrying transferable resistance genes [5].…”

Genomic comparison of diverse Salmonella serovars isolated from swine

“…Chloramphenicol was used to treat MDR infections in human and animals [55][56][57]. The sulfisoxazole resistance genes sul1 (located within 3'-conserved segment [3'-CS] of class 1 integrons) and sul2 (associated with small multicopy plasmids or large transmissible multiresistance plasmids) are the most frequently found genes for sulfonamide resistance among sulfonamide-resistant isolates from food animals and humans, whereas sul3 is detected in various large Salmonella plasmids [58,59].…”

Bacteriophages: the possible solution to treat infections caused by pathogenic bacteria

“…For example, Escherichia coli O104:H4 was found to be resistant to at least 14 different antibiotics (Verstraete et al 2013), and about 90% of Salmonella isolates were found to be resistant to one or more antibiotics tested (Dias de Oliveira et al 2005;Wang et al 2014;Liang et al 2015). Some Salmonella isolates from poultry were found to be resistant to 14 different antibiotics (Adesiji et al 2014;Zhang et al 2014). Moreover, 95% of nosocomial infections are caused by resistant staphylococci (National Center for Health Statistics 2009).…”