Listeria monocytogenes in Export-approved Beef from Mato Grosso, Brazil: Prevalence, Molecular Characterization and Resistance to Antibiotics and Disinfectants

Abstract

The Brazilian state of Mato Grosso is the largest producer and exporter of beef in the country, but few studies of relevance have been conducted to evaluate the microbiological safety of its products. This study aimed to estimate the prevalence of Listeria monocytogenes (LM) in export-approved beef from Mato Grosso and to characterize the isolates in terms of molecular properties and antimicrobial resistance. From a total of 50 samples analyzed, Listeria sp. was isolated in 18 (36% prevalence). Listeria monocytogenes was confirmed in 6 (12% prevalence). Among the serotype groups assessed by multiplex PCR, serotype 4 (4b, 4d or 4e) was the most prevalent. Although antibiotic resistance was not an issue, two strains isolated from different plants showed high resistance to sodium hypochlorite. Overall, this scenario causes concern because it puts at risk not only the Brazilian customer, but also the population of countries that import beef from Mato Grosso.

Assessment of the Prevalence and Drug Susceptibility of Listeria monocytogenes Strains Isolated from Various Types of Meat

“…Similar to our results, Kuan et al [31] reported the L. monocytogenes prevalence of 33.3% in beef offal from different wet markets. In turn, from the total of 50 beef meat samples examined by Teixiera et al [4], six were confirmed as L. monocytogenes positive (12%). The differences reported in the L. monocytogenes prevalence in different meats are affected by various factors, e.g., control measures implementation during the stages of cleaning and disinfection [29].…”

“…People particularly vulnerable to infection are the elderly, pregnant women, newborns, and immunocompromised individuals. In adult males and non-pregnant women listeriosis causes primary meningitis, encephalitis or septicaemia [1][2][3][4].…”

“…A wide range of foodstuffs are reported as the potential source of L. monocytogenes-soft cheese, sausage, unpasteurized milk and dairy products, meats, smoked fish, vegetables, salads, and ready-to-eat (RTE) products [3,4,[6][7][8]. On the basis of the results of the Rapid Alert System for Food and Feed (RASFF) investigation, it can be stated that the products of animal origin are mostly linked to L. monocytogenes infections [9].…”

“…Since L. monocytogenes pathogenicity and persistence in FPE may be related to its serotype, the serological identification of L. monocytogenes strain isolated from food is of major importance for consumer safety [1]. About 90-95% of the strains isolated from contaminated food, animal, and human samples belong to serotypes 1/2a, 1/2b, 1/2c, and 4b, among which mentioned serotype 4b is responsible for the majority of human listeriosis cases and 1/2a serotype is the most prevalent in foods [1,4,6,7,10,17,19].…”

“…The risk of L. monocytogenes occurrence in FPE may increase due to the drug resistance of pathogenic strains. Although L. monocytogenes is thought to maintain a relatively high susceptibility to most of the clinically relevant antimicrobials, the anthropogenic activity (extensive use of antibiotics, cross-resistance to molecules used as growth promoters in animal production) can result in spreading antibiotic resistance among L. monocytogenes strains [4,20].…”