Livestock-Associated Methicillin-Resistant Staphylococcus aureus (MRSA) in Purulent Subcutaneous Lesions of Farm Rabbits.

Vanessa Silva,Telma De Sousa,Carolina Sabença,Rosa Capita,Madalena Vieira-Pinto,Carmen Torres,Gilberto Igrejas,Patrícia Poeta,José L Capelo,Paula Gómez,Carlos Alonso-Calleja

doi:10.3390/foods9040439

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) are one of the main pathogens associated with purulent infections. MRSA clonal complex 97 (CC97) has been identified in a wide diversity of livestock animals. Therefore, we aimed to investigate the antibiotic resistance profiles of MRSA strains isolated from purulent lesions of food-producing rabbits. Samples from purulent lesions of 66 rabbits were collected in a slaughterhouse in Portugal. Samples were seeded onto ORSAB plates with 2 mg/L of oxacillin for MRSA isolation. Susceptibility to antibiotics was tested by the disk diffusion method against 14 antimicrobial agents. The presence of resistance genes, virulence factors and the immune evasion cluster (IEC) system was studied by polymerase chain reaction. All isolates were characterized by multilocus sequence typing (MLST), agr and spa typing. From the 66 samples analyzed, 16 (24.2%) MRSA were detected. All strains were classified as multidrug-resistant as they were resistant to at least three classes of antibiotics. All isolates showed resistance to penicillin, erythromycin and clindamycin. Seven isolates were resistant to gentamicin and harbored the aac(6′)-Ie-aph (2″)-Ia gene. Resistance to tetracycline was detected in 10 isolates harboring the tet(K) gene. The IEC genes were detected in three isolates. MRSA strains belonged to CC97, CC1, CC5, CC15 or CC22. The isolates were assigned to six different spa types. In this study we found a moderate prevalence of multidrug-resistant MRSA strains in food-producing rabbits. This may represent concern for food safety and public health, since cross-contamination may occur, leading to the spread of MRSA and, eventually, the possibility of ingestion of contaminated meat.

Highlights

Oryctolagus cuniculus, commonly known as the European rabbit, is an old species with an enormous ability to adapt to a variety of ecosystems, existing in parallel with—but not dependent on—humans [1,2]
The genotype results for the nuc, rDNA 16S and mecA genes were positive, allowing us to conclude that all the isolates were methicillin-resistant S. aureus, as expected
Methicillin-resistant Staphylococcus aureus (MRSA) strains were found in 24% of samples analyzed, which is in agreement with other studies that reported the presence of S. aureus and MRSA in purulent lesions of farm rabbits [30,31]

Summary

Introduction

Oryctolagus cuniculus, commonly known as the European rabbit, is an old species with an enormous ability to adapt to a variety of ecosystems, existing in parallel with—but not dependent on—humans [1,2]. Rabbit meat has excellent dietary and nutritional properties, and is traditional in Mediterranean cuisine [3]. Slaughterhouses are a key point in monitoring rabbit diseases, as any type of observation and/or information obtained at the slaughterhouse can help to understand and adjust the entire chain [5]. Cutaneous or subcutaneous abscesses are common findings in rabbits of all ages. These purulent lesions are usually the result of contamination of dermal wounds and invasion of subcutaneous tissue by pyogenic bacteria, of which the following can be highlighted: Staphylococcus (S.) spp. Contamination of meat by pathogenic agents is a fundamental point in the area of food safety, since it can compromise the health of consumers.

Objectives

Methods

Results

Discussion

Conclusion