Diversity, distribution and quantification of antibiotic resistance genes in goat and lamb slaughterhouse surfaces and meat products.

Leyre Lavilla Lerma,Charles W Knapp,Antonio Gálvez,Nabil Benomar,Hikmate Abriouel,David Correa Galeote,Ali Al-Ahmad

doi:10.1371/journal.pone.0114252

Leyre Lavilla Lerma, Charles W Knapp + Show 5 more

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https://doi.org/10.1371/journal.pone.0114252

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Abstract

The distribution and quantification of tetracycline, sulfonamide and beta-lactam resistance genes were assessed in slaughterhouse zones throughout meat chain production and the meat products; this study represents the first to report quantitatively monitor antibiotic resistance genes (ARG) in goat and lamb slaughterhouse using a culture independent approach, since most studies focused on individual bacterial species and their specific resistance types. Quantitative PCR (qPCR) revealed a high prevalence of tetracycline resistance genes tetA and tetB in almost all slaughterhouse zones. Sulfonamide resistance genes were largely distributed, while beta-lactam resistance genes were less predominant. Statistical analysis revealed that resistant bacteria, in most cases, were spread by the same route in almost all slaughterhouse zones, except for tetB, blaCTX and blaTEM genes, which occurred in few zones as isolated ‘hot spots.’ The sum of all analyzed ARG indicated that slaughterhouse surfaces and end products act as reservoirs of ARG, mainly tet genes, which were more prevalent in slaughtering room (SR), cutting room (CR) and commercial meat products (MP). Resistance gene patterns suggest they were disseminated throughout slaughterhouse zones being also detected in commercial meat products, with significant correlations between different sampling zones/end products and total resistance in SR, CR and white room (WR) zones, and also refrigerator 4 (F4) and MP were observed. Strategically controlling key zones in slaughterhouse (SR, CR and WR) by adequate disinfection methods could strategically reduce the risks of ARG transmission and minimize the issues of food safety and environment contamination.

Highlights

Antibiotics have been routinely used for therapy, prophylaxis, animal growth promotion and in agricultural operations for several decades
In addition to slaughterhouse surfaces, we examined five meat products (MP; MP1, minced beef; MP2-MP4, ham; MP5, cooked ham) from different supermarkets in Jaen (Spain)
The flow of antibiotic-resistant bacteria (ARB) and their antibiotic resistance genes (ARG) throughout meat chain production has been documented in the literature, mainly in poultry and swine slaughterhouses [21,22,23], and many studies have focused on individual bacteria species and specific resistance traits [24, 25]

Summary

Introduction

Antibiotics have been routinely used for therapy, prophylaxis, animal growth promotion and in agricultural operations for several decades. The prevalence and distribution of antibiotic-resistant bacteria (ARB) have become a threat to food safety; the surveillance and control of spread of antibiotic resistance genes (ARG) throughout food chain has great relevance since consumers are increasingly aware of concerns over antibiotic resistant bacteria in foods, especially those of animal origin. There is a growing interest in ecological studies of antimicrobial resistance in foodborne bacteria. Those bacteria are considered potential reservoirs of resistance as a consequence of the complex transmission routes between farms and consumers. The frequent transfer of resistance genes among host bacteria is becoming more evident with molecular studies, which have shown the distribution of the same gene in different bacteria of animal or human origin [7]. Serious public health hazards arise because of the ability of many bacteria to acquire resistance traits to different antimicrobials

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