Introduction - Methicillin Resistant Staphylococcus aureus (MRSA) has recently become a great concern for animal disease and zoonotic infection. There was evidence that MRSA strains transfer could occur between animals and humans; MRSA transmission to consumer through products of animal origin must not be neglected. Aim - The aim of the present study was to determine the occurrence of MRSA in animals and humans with direct professional exposure to animals from farms in Sicily (Italy). Materials and methods - 728 livestock samples from animals and 45 nasal swabs from humans were obtained. All samples were processed by conventional method using Nutrient Broth and Baird Parker Agar. Staphylococci were identified by biochemical tests (Api Staph System; BioMérieux). Antimicrobial sensitivity to oxacillin (OX) (1 μg) for Staphylococcus spp. isolates was performed on Mueller-Hinton agar plates by Kirby Bauer’s Disc Diffusion method. The identified Staphylococcus spp. strains were subjected to a PCR protocol for the detection of mecA gene. The statistical analysis of the results was made using the z-test by a Primer® software. Results and discussion - 764 and 76 Staphylococcus spp. strains were isolated from livestock and humans, respectively. 331 Staphylococcus spp. strains from animals (43.3%) and 25 from humans (32,9%) were resistant to OX. Among these strains, 29/190 (15,3%) isolated from bovine, 1/49 (2%) from ovine nasal swabs and 3/20 (15%) from cattle breeders were MRSA. There were statistically significant differences between the frequencies of OX resistance among the strains isolated from nasal swabs and milk in both sheep (P = 0.000) and goats (P = 0.039), as well between the frequencies of OX resistance detected in the Staphylococcus spp. strains isolated from nasal swabs of these two species (P = 0.026). Conclusions - Our results let us suppose a wide spread of Staphylococcus spp. resistant to OX in Sicilian farms. A lack correspondence between antimicrobial susceptibility tests and molecular methods was found in the present study. A high β-lactam resistance could occur even when the resistant strains are not detected by the molecular assays as carrying the mecA gene, so it is possible that β-lactam resistance may depend on different mechanisms.

Methicillin Resistant Staphylococcus aureus (MRSA) isolated from livestock and from humans with a professional exposure to animals in farms in Sicily

FOTI, Maria;FISICHELLA, Vittorio;CONTE, Francesca Laura;PASSANTINO, Annamaria;GIACOPELLO, CRISTINA
2012-01-01

Abstract

Introduction - Methicillin Resistant Staphylococcus aureus (MRSA) has recently become a great concern for animal disease and zoonotic infection. There was evidence that MRSA strains transfer could occur between animals and humans; MRSA transmission to consumer through products of animal origin must not be neglected. Aim - The aim of the present study was to determine the occurrence of MRSA in animals and humans with direct professional exposure to animals from farms in Sicily (Italy). Materials and methods - 728 livestock samples from animals and 45 nasal swabs from humans were obtained. All samples were processed by conventional method using Nutrient Broth and Baird Parker Agar. Staphylococci were identified by biochemical tests (Api Staph System; BioMérieux). Antimicrobial sensitivity to oxacillin (OX) (1 μg) for Staphylococcus spp. isolates was performed on Mueller-Hinton agar plates by Kirby Bauer’s Disc Diffusion method. The identified Staphylococcus spp. strains were subjected to a PCR protocol for the detection of mecA gene. The statistical analysis of the results was made using the z-test by a Primer® software. Results and discussion - 764 and 76 Staphylococcus spp. strains were isolated from livestock and humans, respectively. 331 Staphylococcus spp. strains from animals (43.3%) and 25 from humans (32,9%) were resistant to OX. Among these strains, 29/190 (15,3%) isolated from bovine, 1/49 (2%) from ovine nasal swabs and 3/20 (15%) from cattle breeders were MRSA. There were statistically significant differences between the frequencies of OX resistance among the strains isolated from nasal swabs and milk in both sheep (P = 0.000) and goats (P = 0.039), as well between the frequencies of OX resistance detected in the Staphylococcus spp. strains isolated from nasal swabs of these two species (P = 0.026). Conclusions - Our results let us suppose a wide spread of Staphylococcus spp. resistant to OX in Sicilian farms. A lack correspondence between antimicrobial susceptibility tests and molecular methods was found in the present study. A high β-lactam resistance could occur even when the resistant strains are not detected by the molecular assays as carrying the mecA gene, so it is possible that β-lactam resistance may depend on different mechanisms.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/2327023
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