Staphylococcus aureus is a main cause of bovine mastitis and a major pathogen affecting human health. The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) has become a significant concern for both animal health and public health. This study investigated the incidence of MRSA in milk samples collected from dairy cows with clinical mastitis and characterized the MRSA isolates using antimicrobial susceptibility tests and genetic typing methods. In total, 103 S. aureus isolates were obtained from dairy farms in 4 different provinces in China, including Gansu, Shanghai, Sichuan, and Guizhou. Antimicrobial susceptibility testing of these isolates revealed that the resistance rates to penicillin and sulfamethoxazole were high, while the resistance rates to ciprofloxacin and vancomycin were low. Among the 103 isolates, 49 (47.6%) were found to be mecA-positive, indicating the high incidence of MRSA. However, 37 of the 49 mecA-positive isolates were susceptible to oxacillin as determined by antimicrobial susceptibility assays and were thus classified as oxacillin-susceptible mecA-positive S. aureus (OS-MRSA). These isolates could be misclassified as methicillin susceptible Staphylococcus aureus (MSSA) if genetic detection of mecA was not performed. Molecular characterization of selected mecA-positive isolates showed that they were all negative with Panton-Valentine leukocidin (PVL), but belonged to different spa types and SCCmec types. These results indicate that OS-MRSA is common in bovine mastitis in China and underscore the need for genetic methods (in addition to phenotypic tests) to accurately identify MRSA.
References
[1]
Klevens RM, Morrison MA, Nadle J, Petit S, Gershman K, et al. (2007) Invasive methicillin-resistant Staphylococcus aureus infections in the United States. J Am Med Assoc 298: 1763–1771. doi: 10.1001/jama.298.15.1763
[2]
Lowy FD (2003) Antimicrobial resistance: the example of Staphylococcus aureus. J Clin Invest 111: 1265–1273. doi: 10.1172/jci18535
[3]
Cosgrove SE, Sakoulas G, Perencevich EN, Schwaber MJ, Karchmer AW, et al. (2003) Comparison of mortality associated with methicillin-resistant and methicillin-susceptible Staphylococcus aureus bacteremia: a meta-analysis. Clin Infect Dis 36: 53–59. doi: 10.1086/345476
[4]
Tiemersma EW, Bronzwaer SLAM, Lyytik？inen O, Degener JE, Schrijnemakers P, et al. (2004) Methicillin-resistant Staphylococcus aureus in Europe, 1999–2002. Emerg Infect Dis 10: 1627–1633. doi: 10.3201/eid1009.040069
[5]
Chambers HF (2005) Community-associated MRSA—resistance and virulence converge. New Engl J Med 352: 1485–1487. doi: 10.1056/nejme058023
[6]
Hiramatsu K, Cui LZ, Kuroda M, Ito T (2001) The emergency and evolution of methicillin-resistant Staphylococcus aureus. TRENDS Microbiol 9: 486–493. doi: 10.1016/s0966-842x(01)02175-8
[7]
Sakoulas G, Gold HS, Venkataraman L, DeGirolami PC, Eliopoulos GM, et al. (2001) Methicillin-resistant Staphylococcus aureus: comparison of susceptibility testing methods and analysis of mecA-positive susceptible strains. J Clin Microbiol 39: 3946–3951. doi: 10.1128/jcm.39.11.3946-3951.2001
[8]
Labrou M, Michail G, Ntokou E, Pittaras TE, Pournaras S, et al. (2012) Activity of oxacillin versus that of vancomycin against oxacillin-susceptible mecA-positive Staphylococcus aureus clinical isolates evaluated by population analyses, time-kill assays, and a murine thigh infection model. Antimicrob Agents Chemother 56: 3388–3391. doi: 10.1128/aac.00103-12
[9]
Saeed K, Dryden M, Parnaby R (2010) Oxacillin-susceptible MRSA, the emerging MRSA clone in the UK? J Hosp Infect 76: 267–268. doi: 10.1016/j.jhin.2010.03.004
[10]
Hososaka Y, Hanaki H, Endo H, Suzuki Y, Nagasawa Z, et al. (2007) Characterization of oxacillin-susceptible mecA-positive Staphylococcus auerus: a new type of MRSA. J Infect Chemother 13: 79–86. doi: 10.1007/s10156-006-0502-7
[11]
Ikonomidis A, Michail G, Vasdeki A, Labrou M, Karavasilis V, et al. (2008) In vitro and in vivo evaluations of oxacillin efficiency against mecA-positive oxacillin-susceptible Staphylococcus aureus. Antimicrob Agents Chemother 52: 3905–3908. doi: 10.1128/aac.00653-08
[12]
Feedtrade website (2013) Available: http://www.feedtrade.com.cn/whey/milk_ma？rket/2013-01-17/2013257.html.Accessed 2013 Jan 17.
[13]
Bai LX, Hao ML, Qing JH (2010) Research advances in the treatment of dairy cow mastitis. Chin Qing Hai J Anim Vet Sci 5: 45–46.
[14]
Jin YZ, Wan SP, Jiang FM, Gong ZL, Cao J, et al. (2011) Isolation and susceptibility testing of major pathogenic bacteria and prevalence of cow mastitis. Anim Husb Vet Med 43: 64–67.
[15]
Cao LT, Hu SH (2010) Distribution of major pathogenic bacteria of cow mastitis in milk. J Anhui Agri Sci 38: 19541–19542.
[16]
Saini V, McClure JT, Scholl DT, DeVries TJ, Barkema HW (2013) Herd-level relationship between antimicrobial use and presence or absence of antimicrobial resistance in gram-negative bovine mastitis pathogens on Canadian dairy farms. J Dairy Sci 96: 4965–4976.
[17]
Devriese LA, Van Dammme LR, Fameree L (1972) Methicillin- (cloxacillin)-resistant Staphylococcus aureus strains isolated from bovine mastitis case. Zentralbl Veterinarmed B 19: 598–605. doi: 10.1111/j.1439-0450.1972.tb00439.x
[18]
Juhász-Kaszanyitzky é, Jánosi S, Somogyi P, Dán á, Van Der Graaf-van Bloois L, et al. (2007) MRSA transmission between cows and humans. Emerg Infect Dis 13: 630–632. doi: 10.3201/eid1304.060833
[19]
Monecke S, Kuhnert P, Hotzel H, Slickers P, Ehricht R (2007) Microarray based study on virulence-associated genes and resistance determinants of Staphylococcus aureus. Vet Microbiol 125: 128–140. doi: 10.1016/j.vetmic.2007.05.016
[20]
Fessler A, Scott C, Kadlec K, Ehricht R, Monecke S, et al. (2010) Characterization of methicillin-resistant Staphylococcus aureus ST398 from cases of bovine mastitis. J Antimicrob Chemother 65: 619–625. doi: 10.1093/jac/dkq021
[21]
Huber H, Koller S, Glezendanner N, Stephan R, Zweifel C (2010) Prevalence and characteristics of methicillin-resistant Staphylococcus aureus in humans in contact with farm animals, in livestock, and in food of animal origin, Switzerland, 2009. Euro Surveill 15: pii = 19542.
[22]
Garcia-Alvarez L, Holden MTG, Lindsay H, Webb CR, Brown DFJ, et al. (2011) Methicillin-resistant Staphylococcus aureus with a novel mecA homologue in human and bovine population in the UK and Denmark: a descriptive study. Lancet Infect Dis 11: 595–603. doi: 10.1016/s1473-3099(11)70126-8
[23]
Paterson GK, Morgan FJE, Harrison EM, Peacock SJ, Parkhill J, et al. (2013) Prevalence and properties of mecC methicillin-resistant Staphylococcus aureus (MRSA) in bovine bulk tank milk in Great Britain. J Antimicrob Chemother Oct 23. doi: 10.1093/jac/dkt417
[24]
Holmes MA, Zadoks RN (2011) Methicillin resistant S. aureus in human and bovine mastitis. J Mammary Gland Biol Neoplasia 16: 373–382. doi: 10.1007/s10911-011-9237-x
[25]
Nam HM, Lee AL, Jung SC, Kim MN, Jang GC, et al. (2011) Antimicrobial susceptibility of Staphylococcus aureus and characterization of methicillin-resistant Staphylococcus aureus isolated from bovine mastitis in Korea. Foodborne Pathog Dis 8: 231–238. doi: 10.1089/fpd.2010.0661
[26]
Türkyilmaz S, Tekbiyik S, Oryasin E, Bozdogan B (2010) Molecular epidemiology and antimicrobial resistance mechanisms of methicillin-resistant Staphylococcus aureus isolated from bovine milk. Zoonoses Public Health 57: 197–203. doi: 10.1111/j.1863-2378.2009.01257.x
[27]
Cui SH, Li JY, Hu CQ, Jin SH, Li FQ, et al. (2009) Isolation and characterization of methicillin-resistant Staphylococcus aureus from swine and works in China. J Antimicrob Chemother 64: 680–683. doi: 10.1093/jac/dkp275
[28]
Zhang WJ, Hao ZH, Wang Y, Cao XY, Logue CM, et al. (2011) Molecular characterization of methicillin-resistant Staphylococcus aureus from pet animals and veterinary staff in China. Vet J 190: e125–e129. doi: 10.1016/j.tvjl.2011.02.006
[29]
Wang DF, Duan XH, Wu JY, Yang XY, Li JJ, et al. (2011) The current status of the drug resistance and evolutionary relationship of MSSA and MRSA isolates from bovine of China. Acta Veterinaria Et Zootechnica Sinica 42: 1416–1425.
[30]
Bannerman TL (2003) Staphylococcus, Micrococcus, other catalase-positive cocci that grow aerobically. In Manual of Clinical Microbiology, pp: 384–404. Edited by Murray PR, Baron EJ, Jorgensen JH, Pfaller MA, Yolken RH. Washington, DC: ASM Press.
[31]
Turk DC, Porter IA (1978) A Short Textbook of Medical Microbiology, 4th edn London: Hodder and Stoughton.
[32]
Clinical and Laboratory Standards Institute (2010) Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated From Animals: Informational Supplement. CLSI Document M100-S20. Clinical and Laboratory Standards Institute, Wayne PA.
[33]
Galdiero E, Liguori G, Isanto MD, Damiano N, Sommese L (2003) Distribution of mecA among methicillin-resistant clinical staphylococcal strains isolated at hospitals in Naples, Italy. Eur J Epidemiol 18: 139–145. doi: 10.1023/a:1023067930211
Zhang KY, McClure JN, Elsayed S, Louie T, Conly JM (2005) Novel Multiplex PCR assay for characterization and concomitant subtyping of Staphylococcus cassette chromosome mec types I to V in methicillin-resistant Staphylococcus aureus. J Clin Microbiol 45: 5026–5033. doi: 10.1128/jcm.43.10.5026-5033.2005
[36]
Lina G, Piémont Y, Godail-Gamot F, Bes M, Peter MO, et al. (1999) Involvement of Panton-Valentine Leukocidin-Producing Staphylococcus aureus in primary skin infection and pneumonia. Clin Infect Dis 29: 1128–1132. doi: 10.1086/313461
[37]
Su Y, Pu WX, Chen ZH, Deng HP (2012) Antimicrobial resistance analysis and detection of methicillin-resistant Staphylococcus aureus (MRSA) among Staphylococcus aureus strains isolated from bovine mastitis. Scientia Agricultura Sinica 45: 3602–3607.
[38]
Hendriksen RS, Mevius DJ, Schroeter A, Teale C, Meunier D, et al. (2008) Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002–2004. Acta Vet Scan 50: 28. doi: 10.1186/1751-0147-50-28
[39]
Turutoglu H, Ercelik S, Ozturk D (2006) Antibiotic resistance of Staphylococcus aureus and coagulase-negative Staphylococci isolated from bovine mastitis. Bull Vet Inst Pulawy 50: 41–45.
[40]
Turutoglu H, Hasoksuz M, Ozturk D, Yildirim M, Sagnak S (2009) Methicillin and aminoglycoside resistance in Staphylococcus aureus isolates from bovine mastitis and sequence analysis of their mecA genes. Vet Res Commun 33: 945–956. doi: 10.1007/s11259-009-9313-5
[41]
Jannati E, Arzanlou M, Habibzadeh S, Mohammadi S, Ahadi P, et al. (2013) Nasal colonization of mecA-positive, oxacillin-susceptible, methicillin-resistant Staphylococcus aureus isolates among nursing staff in an Iranian teaching hospital. Am J Infect Control 41: 1122–1124. doi: 10.1016/j.ajic.2013.02.012
[42]
Sharff KA, Monecke S, Slaughter S, Forrest G, Pfeiffer C, et al. (2012) Genotypic resistance testing creates new treatment challenges: two cases of oxacillin-susceptible methicillin-resistant Staphylococcus aureus. J Clin Microbiol 50: 4151–4153. doi: 10.1128/jcm.01564-12
[43]
Giannouli S, Labrou M, Kyritsis A, Ikonomidis A, Pournaras S, et al. (2010) Detection of mutations in the FemXAB protein family in oxacillin-susceptible mecA-positive Staphylococcus aureus clinical isolates. J Antimicrob Chemother 65: 626–633. doi: 10.1093/jac/dkq039
[44]
Tokajian S, Haddad D, Andraos R, Hashwa F, Araj G (2011) Toxins and antibiotics resistance in Staphylococcus aureus isolated from a major hospital in Lebanon. ISRN Microbiol 812049: 9. doi: 10.5402/2011/812049
[45]
Ellington MJ, Yearwood L, Ganner M, East C, Kearns AM (2008) Distribution of the ACME-arcA gene among methicillin-resistant Staphylococcus aureus from England and Wales. J Antimicrob Chemother 61: 73–77. doi: 10.1093/jac/dkm422
[46]
Aires-de-Sousa M, Parente CESR, Vieira-da-Motta O, Bonna ICF, Silva DA, et al. (2007) Characterization of Staphylococcus aureus isolates from Buffalo, Bovine, Ovine, and Caprine milk samples collected in Rio de Janeiro State, Brazil. Appl Environ Microbiol 73: 3845–3849. doi: 10.1128/aem.00019-07
[47]
Zecconi A, Cesaris L, Liandris E, Daprà V, Piccinini R (2006) Role of several Staphylococcus aureus virulence factors on the inflammatory response in bovine mammary gland. Microb Pathogenesis 40: 177–183. doi: 10.1016/j.micpath.2006.01.001
[48]
Boyle-Vavra S, Daum RS (2007) Community-acquired methicillin-resistant Staphylococcus aureus: the role of Panton-Valentine leukocidin. Lab Invest 87: 3–9. doi: 10.1038/labinvest.3700501
