Antimicrobial residues and resistance against critically important antimicrobials in non-typhoidal Salmonella from meat sold at wet markets and supermarkets in Vietnam

Abstract

A B S T R A C TExcessive antimicrobial usage and deficiencies in hygiene in meat production systems may result in undesirable human health hazards, such as the presence of antimicrobial drug residues and non-typhoidal Salmonella (NTS), including antimicrobial resistant (AMR) NTS. Recently, Vietnam has witnessed the emergence of integrated intensive animal production systems, coexisting with more traditional, locally-sourced wet markets. To date no systematic studies have been carried out to compare health hazards in beef, pork and chicken in different production systems. We aimed to: (1) estimate the prevalence of antimicrobial residues in beef, pork and chicken meat; (2) investigate the prevalence and levels of NTS contamination; and (3) investigate serovar distribution and AMR against critically important antimicrobials by animal species and type of retail (wet market vs. supermarket) in Vietnam. Fresh pork, beef and chicken meat samples (N = 357) sourced from wet markets and supermarkets in Ho Chi Minh City (HCMC), Hanoi and Dong Thap were screened for antimicrobial residues by PremiTest, and were further investigated by Charm II. Samples from HCMC (N = 113) were cultured using ISO 6579:2002/Amd 1:2007. NTS bacteria were quantified using a minimum probable number (MPN) technique. NTS isolates were assigned to serovar by Multilocus Sequence Typing (MLST), and were investigated for their phenotypic susceptibility against 32 antimicrobials. A total of 26 (7.3%) samples tested positive by PremiTest (9.5% beef, 4.1% pork and 8.4% chicken meat). Sulfonamides, tetracyclines and macrolides were detected by Charm in 3.1%, 2.8% and 2.0% samples, respectively. Overall, meat samples from wet markets had a higher prevalence of residues than those from supermarkets (9.6% vs. 2.6%) (p = 0.016). NTS were isolated from 68.4% samples from HCMC. Chicken samples from wet markets had by far the highest NTS counts (median 3.2 log MPN/g). NTS isolates displayed high levels of resistance against quinolones (52.2%) and β-lactams (49.6%), but low levels against 3rd generation cephalosporins (4.4%) and aminoglycosides (0.8%). The highest adjusted prevalence of multidrug resistance (MDR) corresponded to isolates from chicken meat and pork (OR 8.3 and 1.8, respectively) (baseline = beef). S. Kentucky was the most common serovar identified (11 from chicken, 1 from beef) and 91.7% isolates was MDR. 11/12 isolates corresponded to ST198, a worldwide-disseminated multiresistant NTS clone. We recommend stepping up policy measures to promote responsible antimicrobial use in animal production, as well as awareness about withdrawal periods to limit the hazard of residues in animal products, and improving slaughtering/hygiene procedures to limit cross-contamination with NTS, particularly in poultry wet markets.

Molecular Characterization Of Pathogenic Salmonella Spp From Raw Beef In Karachi, Pakistan

“…The prevalence of Salmonella in minced meat has been reported up to 12 percent by [41] which indicates high microbiological risk because Salmonella must not be present in meat when it is sold. Similar results have also been reported by [42]. Some research studies have reported 5%-20% prevalence of Salmonella in meat [43,44].…”

“…There are few reports describing the prevalence of S. Pullorum in beef and other meats i.e., fish, pork etc. [42].…”

Quantification and rep‐PCR characterization of Salmonella spp. in retail meats and hospital patients in Northern Thailand

“…The high prevalence of Salmonella contamination strongly suggests shortcomings in hygiene practices in retail stores, for example, storage temperature, packaging and/or holding time, all of which are important factors in Salmonella multiplication (Patchanee et al, ; Soltan Dallal, Sharifi Yazdi, Mirzaei, & Kalantar, ). Together, these factors increase the opportunity for Salmonella growth in fresh markets, resulting in a higher prevalence of Salmonella contamination than in other retail outlets (Murugadas et al, ; Nhung et al, ; Wong, Nicol, Cook, & MacDiarmid, ). Meats sold retail at supermarkets were in seal packages and stored on shelves at approximately 4°C at all times, leading to the lowest incidence of Salmonella contamination (50.00%, 95% CI: 21.71–78.29).…”

“…Together, these factors increase the opportunity for Salmonella growth in fresh markets, resulting in a higher prevalence of Salmonella contamination than in other retail outlets (Murugadas et al, 2015;Nhung et al, 2018;Wong, Nicol, Cook, & MacDiarmid, 2007). Meats sold retail at supermarkets were in seal packages and stored on shelves at approximately 4°C at all times, leading to the lowest incidence of Salmonella contamination (50.00%, 95% CI: 21.71-78.29).…”

Vietnam Development Report 2019

“…Fourth, marketed perishable foods have high rates of microbiological and chemical contamination, with the most serious issues related to meat. For example, in a recent study, Nguyen and others (2018) found the presence of non-typhoidal Salmonella-a leading source of foodborne diseases for nearly 900,000 illnesses annually-in 71 percent of chicken samples taken in Hanoi and HCMC. The Salmonella prevalence rate was higher in wet markets (90 percent) than in supermarkets (53 percent).…”