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Genotypic and Phenotypic-Based Assessment of Antibiotic Resistance and Profile of Staphylococcal Cassette Chromosome mec in the Methicillin-Resistant Staphylococcus aureus Recovered from Raw Milk

Authors Rahi A, Kazemeini H, Jafariaskari S, Seif A, Hosseini S, Safarpoor Dehkordi F

Received 2 September 2019

Accepted for publication 4 December 2019

Published 30 January 2020 Volume 2020:13 Pages 273—283


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Sahil Khanna

Azar Rahi, 1 Hamidreza Kazemeini, 2 Sedigheh Jafariaskari, 3 Ali Seif, 4 Sahar Hosseini, 5 Farhad Safarpoor Dehkordi 6

1Department of Microbiology, Kazerun Branch, Islamic Azad University, Kazerun, Iran; 2Department of Food Hygiene, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran; 3Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran; 4Doctor Veterinary Medicine, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran; 5Master of Food Science and Technology, Faculty of Agriculture and Food Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran; 6Halal Research Center of IRI, FDA, Tehran, Iran

Correspondence: Hamidreza Kazemeini
Department of Food Hygiene, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran

Background: Multidrug resistant methicillin-resistant Staphylococcus aureus (MRSA) bacteria are determined to be one of the chief causes of foodborne diseases around the world.
Purpose: This research was done to assess the genotypic and phenotypic profiles of antibiotic resistance and distribution of Staphylococcus cassette chromosome mec (SCCmec) types amongst the MRSA bacteria recovered from raw milk.
Methods: Five-hundred and ninety raw milk samples were collected and examined. MRSA bacteria were recognized using susceptibility evaluation toward oxacillin and cefoxitin disks. Profile of antibiotic resistance genes and SCCmec types were determined using the PCR. Antibiotic resistance pattern of isolates was examined using the disk diffusion.
Results: Thirty-nine out of 590 raw milk samples (6.61%) were positive for S. aureus. Twenty-eight out of 39 (71.79%) bacteria were defined as MRSA bacteria. Raw buffalo (80%) milk samples had the maximum incidence of MRSA, while raw camel (33.33%) had the minimum. MRSA bacteria harbored the maximum incidence of resistance toward penicillin (100%), tetracycline (100%), erythromycin (82.14%), gentamicin (78.57%) and trimethoprim-sulfamethoxazole (78.57%). Incidence of resistance toward more than eight classes of antibiotic agents was 28.57%. The most frequently distinguished antibiotic resistance markers were blaZ (100%), tetK (85.71%), dfrA1 (71.42%), aacA-D (67.85%), ermA (50%) and gyrA (42.85%). SCCmec IVa (29.62%), V (25%), III (14.81%) and IVb (11.11%) were the most frequently distinguished types.
Conclusion: Raw milk of dairy animals maybe sources of multidrug resistant MRSA which pose a hygienic threat concerning the consumption of raw milk in Iran. Nevertheless, further investigations are necessary to understand supplementary epidemiological features of MRSA in raw milk.

Keywords: methicillin-resistant Staphylococcus aureus, raw milk, antibiotic resistance mechanisms, SCCmec types

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