Methicillin-resistant Staphylococcus aureus in Retail Meat, Detroit, Michigan, USA

DOI: 10.3201/eid1706.101095

Suggested citation for this article: Bhargava K, Wang X, Donabedian S, Zervos M, da Rocha L, Zhang Y. Methicillin-resistant Staphylococcus aureus in retail meat, Detroit, Michigan, USA [letter]. Emerg Infect Dis. 2011 Jun; [Epub ahead of print]

Methicillin-resistant Staphylococcus aureus in Retail Meat, Detroit, Michigan, USA

To the Editor: Because methicillin-resistant Staphylococcus aureus (MRSA) has been identified in retail meat worldwide (1–4), the potential exists for its transmission to humans. Of the various meat products surveyed, pork had the highest contamination rate in the United States and Canada (1,2), as did beef in Korea (3) and poultry in the Netherlands (4). The study in Korea also observed MRSA from chicken, which demonstrated sequence type (ST) 692 by multilocus sequence typing (MLST), a type distinct from that isolated in beef and pork. Despite sample size variations, these studies suggested that MRSA contamination in different meat categories can vary by location and that molecular distinction may exist among MRSA isolates in meat of different origin.

We collected 289 raw meat samples (156 beef, 76 chicken, and 57 turkey) from 30 grocery stores in Detroit, Michigan, USA, during August 2009–January 2010. Up to 3 presumptive S. aureus colonies per sample were identified by coagulase test and species-specific PCR (1). Antimicrobial drug MICs were determined and interpreted according to Clinical and Laboratory Standards Institute guidelines (5). S. aureus were characterized by pulsed-field gel electrophoresis (PFGE), mecA identification, SCCmec typing, Panton-Valentine leukocidin identification, agr typing, MLST, and spa typing as described (1,6).

Sixty-five (22.5%) samples yielded S. aureus: 32 beef (20.5%), 19 chicken (25.0%), and 14 turkey (24.6%) samples. Six samples, consisting of 2 beef (1.3%), 3 chickens (3.9%), and 1 turkey (1.7%), were positive for MRSA as evidenced by the presence of mecA. The overall lower prevalence of S. aureus and MRSA than found in a previous study in the United States (40% and 5%, respectively) (1) might be explained by our exclusion of pork because pork and swine production have been major reservoirs of MRSA (4,7). However, different geographic location Page 2 of 4

and cold sampling seasons in this study also might have caused the variations. The only multidrug-resistant MRSA isolate in this study (MRSA1) was from beef and was resistant to ß-lactams, macrolides, and fluoroquinolones (Figure).

Although an extra band was generated in MRSA2a, 2b, 3, 5, and 6 by PFGE, all 9 MRSA isolates belonged to USA300 (Figure). Multiple isolates from the same samples (MRSA2a and 2b; MRSA4a, 4b, and 4c) demonstrated indistinguishable PFGE patterns and other characteristics, which suggested identical MRSA clones. Moreover, MLST, SCCmec typing, agr typing, and pvl detection showed all strains to be positive for ST8, SCCmec IVa, agr I, and Panton-Valentine leukocidin, which are typical characteristics of USA300 clones. However, spa typing identified 2 distinct spa types, t008 (11–19–12-21–17-34–24–34–22–25) and t2031 (11–19–12-12–34-34–24–34–22–25) (repeat variants in boldface), which differed by 5 nucleotides. t008, the most common spa type of USA300, was identified in 6 isolates of beef, chicken, and turkey origin, whereas t2031 was recovered from MRSA4a, 4b, and 4c from a chicken sample. The nucleotide variation in t2031 caused amino acid changes from glycine-asparagine in t008 to asparagine-lysine. The single nucleotide difference between repeats 12 (GGT) and 21 (GGC) and repeats 34 (AAA) and 17 (AAG) resulted in no amino acid change, with glycine and lysine encoded, respectively.

Unlike studies in Europe, where researchers have reported the animal MRSA clone ST398 from various meat products (4), all MRSA isolates in our study were USA300, which suggests a possible human source of contamination during meat processing (1). The failure to identify ST398 in the US retail meat also indicates that the human MRSA clones might be better adapted in meat processing than ST398 in this country. Since ST398 is widespread in animals and meat in Europe and has been isolated from other parts of the world (8), it is not too bold to predict that ST398 might appear in US meat in the future, especially after the recent report of ST398 from US swine (7).

The 5-nt difference between t2031 and t008 implicates multiple MRSA clones in poultry. Previous studies have shown spa variants of USA300 from clinical cases associated with distinctive symptoms (9,10). A single repeat variant, t024, showed substantial genetic, epidemiologic, and clinical differences from t008 in Denmark (10). Researchers in Japan also recovered 2 spa variants of USA300: t024, which causes blood infections, and t711, which is Page 3 of 4

associated with subcutaneous abscesses (9). In both studies, t024 behaved as hospital-associated MRSA, suggesting that spa variants of USA300 could lead to different clinical outcomes. Therefore, we can reasonably assume that variants with a meat origin also might have different public health implications; further research on their virulence potential would be helpful to elucidate this possibility.

Despite the recovery of MRSA from retail chicken and t2031 that has an antibiogram distinct from t008, except for ß-lactam resistance, several questions remain about whether more spa variants are present in poultry (or meat). These include whether t2031 is more adaptable to chicken production because of the 2 amino acid difference from t008, or whether t2031 is linked with specific antimicrobial drug resistance phenotypes other than ß-lactam resistance.

Kanika Bhargava, Xiaogang Wang, Susan Donabedian, Marcus Zervos, Liziane da Rocha, and Yifan Zhang

Author affiliations: Wayne State University, Detroit, Michigan, USA (K. Bhargava, X. Wang, L. da Rocha, Y. Zhang) and Henry Ford Health Systems, Detroit (S. Donabedian, M. Zervos)

References

1. Pu S, Han F, Ge B. Isolation and characterization of methicillin-resistant Staphylococcus aureus strains from Louisiana retail meats. Appl Environ Microbiol. 2009;75:265–7. PubMed doi:10.1128/AEM.01110-08

2. Weese JS, Avery BP, Reid-Smith RJ. Detection and quantification of methicillin-resistant Staphylococcus aureus (MRSA) clones in retail meat products. Lett Appl Microbiol. 2010;51:338–42. PubMed doi:10.1111/j.1472-765X.2010.02901.x

3. Lim SK, Nam HM, Park HJ, Lee HS, Choi MJ, Jung SC, et al. Prevalence and characterization of methicillin-resistant Staphylococcus aureus in raw meat in Korea. J Microbiol Biotechnol. 2010;20:775–8. PubMed

4. de Boer E, Zwartkruis-Nahuis JT, Wit B, Huijsdens XW, de Neeling AJ, Bosch T, et al. Prevalence of methicillin-resistant Staphylococcus aureus in meat. Int J Food Microbiol. 2009;134:52–6. PubMed doi:10.1016/j.ijfoodmicro.2008.12.007

5. Clinical and Laboratory Standards Institute. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, 7th ed. Wayne (PA): The Institute; 2006. Page 4 of 4

6. Strommenger B, Cuny C, Werner G, Witte W. Obvious lack of association between dynamics of epidemic methicillin-resistant Staphylococcus aureus in central Europe and agr specificity groups. Eur J Clin Microbiol Infect Dis. 2004;23:15–9. PubMed doi:10.1007/s10096-003-1046-8

7. Smith TC, Male MJ, Harper AL, Kroeger JS, Tinkler GP, Moritz ED, et al. Methicillin-resistant Staphylococcus aureus (MRSA) strain ST398 is present in midwestern U.S. swine and swine workers. PLoS ONE. 2009;4:e4258. PubMed doi:10.1371/journal.pone.0004258

8. Weese JS, Reid-Smith R, Rousseau J, Avery B. Methicillin-resistant Staphylococcus aureus (MRSA) contamination of retail pork. Can Vet J. 2010;51:749–52. PubMed

9. Higuchi W, Mimura S, Kurosawa Y, Takano T, Iwao Y, Yabe S, et al. Emergence of the community-acquired methicillin-resistant Staphylococcus aureus USA300 clone in a Japanese child, demonstrating multiple divergent strains in Japan. J Infect Chemother. 2010;16:292–7. PubMed doi:10.1007/s10156-010-0051-y

10. Larsen AR, Goering R, Stegger M, Lindsay JA, Gould KA, Hinds J, et al. Two distinct clones of methicillin-resistant Staphylococcus aureus (MRSA) with the same USA300 pulsed-field gel electrophoresis profile: a potential pitfall for identification of USA300 community-associated MRSA. J Clin Microbiol. 2009;47:3765–8. PubMed doi:10.1128/JCM.00934-09

Address for correspondence: Yifan Zhang, Department of Nutrition and Food Science, Wayne State University, 3009 Science Hall, 5045 Cass Ave, Detroit, MI 48202, USA; email: yifanzhang@wayne.edu

Figure. Dendrogram showing comparison of SmaI pulsed-field gel electrophoresis patterns, SCCmec type, PVL content, and agr type of methicillin-resistant Staphylococcus aureus (MRSA) isolated from meat samples. All MRSA isolates were resistant to ß-lactam antimicrobial drugs (ampicillin, penicillin, and oxacillin) and grew on the 6 µg/mL of cefoxitin for screening methicillin resistance. *Isolates with the same arabic numbers were from the same sample; †only resistance to non–ß-lactam antimicrobial drugs was listed. ID, identification; MLST, multilocus sequence typing; PVL, Panton-Valentine leukocidin; CIP, ciprofloxacin; ERY, erythromycin; LEVO, levofloxacin; TET, tetracycline.

http://www.cdc.gov/eid/content/17/6/pdfs/10-1905.pdf


May 11, 2011

Human-type MRSA found in Detroit raw meat

Researchers testing retail meat samples in Detroit found that almost a fourth contained Staphylococcus aureus and 2% contained methicillin-resistant S aureus (MRSA). In a letter to Emerging Infectious Diseases today, the scientists report that they collected 289 raw meat samples (156 beef, 76 chicken, and 57 turkey) from 30 grocery stores from August 2009 through January 2010. Of those samples, 65 (22.5%) yielded S aureus via coagulase test and polymerase chain reaction (PCR): 32 beef (20.5%), 19 chicken (25.0%), and 14 turkey (24.6%) samples. Six samples (2 beef [1.3%], 3 chicken [3.9%], and 1 turkey [1.7%]), were positive for MRSA, while only one sample, a beef one, contained multidrug-resistant MRSA. Furthermore, the MRSA was the human type, USA300, which the authors said could indicate a human rather than animal source of meat contamination. They said similar studies in European meat typically show ST398, an animal MRSA clone. They noted that the percentage of positive MRSA samples is lower than in an earlier study in Louisiana meat, perhaps because the Michigan researchers didn't test pork, noting that swine production has been identified as a reservoir of MRSA. They wrote that although USA300 might be better adapted to meat processing in the United States, ST398 might someday appear as a contaminant in US meat, given its recent identification in US swine.

http://www.cidrap.umn.edu/cidrap/content/fs/food-disease/news/may1111newsscan.html





Monday, April 18, 2011

Multidrug-Resistant Staphylococcus aureus in US Meat and Poultry

http://staphmrsa.blogspot.com/2011/04/multidrug-resistant-staphylococcus.html




Tuesday, May 10, 2011

Food safety for whom? Corporate wealth versus people's health

http://fdafailedus.blogspot.com/2011/05/food-safety-for-whom-corporate-wealth.html





Horizon Acres 3/18/11

Department of Health and Human Services Public Health Service Food and Drug Administration Cincinnati District Office Central Region 6751 Steger Drive Cincinnati, OH 45237-30977 Telephone: (513) 679-2700 FAX: (513) 679-2761

WARNING LETTER CIN-11-65585-06

March 18, 2011

United Parcel Service

Mr. Kenneth D. Weaver, General Manager Horizon Acres 6728 Zuercher Road

Dalton, Ohio 44618

Dear Mr. Weaver:

On November 10, 12, 19,24, 2010, and December 20, 2010, the U.S. Food and Drug Administration (FDA) conducted an investigation of your veal calf operation located at 6728 Zuercher Road, Dalton, Ohio 44618. This letter notifies you of the violations of the Federal Food, Drug, and Cosmetic Act (the FD&C Act) that we found during our investigation of your operation. You can find the FD&C Act and its associated regulations on the Internet through links on FDA's web page at www.fda.gov1.

We found that you offered for sale an animal for slaughter as food that was adulterated. Under section 402(a)(2)(C)(ii) of the FD&C Act, 21 U.S.C. § 342(a)(2)(C)(ii), a food is deemed to be adulterated if it bears or contains a new animal drug that is unsafe under section 512 of the FD&C Act, 21 U.S.C. § 360b. Further, under section 402(a)(4) of the FD&C Act, 21 U.S.C. § 342(a)(4), a food is deemed to be adulterated if it has been held under insanitary conditions whereby it may have been rendered injurious to health.

Specifically, our investigation revealed that on or about June 22, 2010, you sold an unidentified, untagged veal calf for slaughter as food. On or about June 22, 2010, (b)(4) slaughtered this animal. United States Department of Agriculture, Food Safety and Inspection Service (USDA/FSIS) analysis of tissue samples collected from this animal identified the presence 0.28 parts per million (ppm) of flunixin in the liver tissue. FDA has established a tolerance of 0.125 ppm for residues of flunixin in the liver of cattle as codified in 21 C.F.R. 556.286(b)(1)(i). However, this tolerance does not apply to use of Suppressor (flunixin meglumine) Injectable Solution, ANADA 200-308, in veal calves (pre-ruminating calves), and there is no acceptable level of residue associated with use of flunixin meglumine in veal calves (pre-ruminating calves). The presence of this drug in edible tissue from this animal in this amount causes the food to be adulterated within the meaning of section 402(a)(2)(C)(ii) of the FD&C Act, 21 U.S.C. § 342(a)(2)(C)(ii).

Our investigation also found that you hold animals under conditions that are so inadequate that medicated animals bearing potentially harmful drug residues are likely to enter the food supply. For example, you failed to maintain complete treatment records and segregate treated animals. Food from animals held under such conditions is adulterated within the meaning of section 402(a)(4) of the FD&C Act, 21 U.S.C. § 342(a)(4).

We also found that you adulterated the new animal drugs Suppressor (flunixin meglumine) ANADA 200-308, Dexamethasone ANADA 200-312, Ceftiflex sterile powder (ceftiofur sodium) ANADA 200-420, PennOne Pro (penicillin G procaine) NADA 65-010, Amoxicillin capsules NDC 65862-017-05, Sulfamethoxazole and Trimethoprim Double Strength tablets NDC 53746-272-05 (SMZ-TMP tablets), and Pennchlor 64 (chlortetracycline HCI) ANADA 200-295. Specifically, our investigation revealed that you did not use these drugs as directed by their approved labeling. Use of these drugs in this manner is an extralabel use. 21 C.F.R. § 530.3(a).

The extralabel use of approved animal or human drugs in animals is allowed under the FD&C Act only if the extralabel use complies with sections 512(a)(4) and (5) of the FD&C Act, 21 U.S.C. § 360b(a)(4) and (5), and 21 C.F.R. Part 530, including that the use must be by or on the lawful order of a licensed veterinarian within the context of a valid veterinarian/client/patient relationship.

Our investigation found that you administered flunixin meglumine to veal calves without following the withdrawal period as stated in the approved labeling. Your extralabel use of flunixin meglumine was not under the supervision of a licensed veterinarian, in violation of 21 C.F.R. § 530.11(a) and your extralabel use of flunixin meglumine resulted in an illegal drug residue, in violation of 21 C.F.R. § 530.11(c).

Our investigation found that you administered dexamethasone to veal calves without following the route of administration and the withdrawal period as stated in the approved labeling. Your extralabel use of Dexamethasone was not under the supervision of a licensed veterinarian, in violation of 21 C.F.R. § 530.11 (a).

Our investigation found that you administered ceftiofur sodium to veal calves without following the withdrawal period as stated in the approved labeling. Your extralabel use of ceftiofur sodium was not under the supervision of a licensed veterinarian, in violation of 21 C.F.R. § 530.11(a).

Our investigation found that you administered penicillin G procaine to veal calves without following the route of administration and the withdrawal period as stated in the approved labeling. Your extralabel use of penicillin G procaine was not under the supervision of a licensed veterinarian, in violation of 21 C.F.R. § 530.11(a).

Our investigation found that you administered amoxicillin and sulfamethoxazole and trimethoprim (SMZ-TMP) to veal calves without following the route of administration and duration of the treatment as stated in their approved labeling. Your extralabel use of Amoxicillin and SMZ-TMP were not under the supervision of a licensed veterinarian, in violation of 21 C.F.R. § 530.11 (a) and your use of amoxicillin and SMZ-TMP in or on feed, is in violation of 21 C.F.R. § 530.11(b).

Our investigation found that you administered chlortetracycline HCI to veal calves without following the duration of treatment. Your use of chlortetracycline HCI was not under the supervision of a licensed veterinarian, and is in violation of 21 C.F.R. § 530.11

(a) and your use of pennchlor 64 in or on feed, is in violation of 21 C.F.R. § 530.11

(b). Because your use of these drugs was not in conformance with their approved labeling and did not comply with 21 C.F.R. Part 530, you caused the drug(s) to be unsafe under section 512(a) of the FD&C Act, 21 U.S.C. § 360b(a), and adulterated within the meaning of section 501(a)(5) of the FD&C Act, 21 U.S.C. § 351(a)(5).

In addition, you adulterated the liquid animal feed within the meaning of section 501(a)(6) of the FD&C Act, 21 U.S.C. § 351(a)(6), when you added sulfamethoxazole and trimethoprim, Amoxicillin, and chlortetracycline HCI, and you failed to use the medicated feed in conformance with its approved labeling. Your use of this medicated feed without following the animal class as directed by the approved labeling caused this medicated feed to be unsafe under section 512(a)(2) of the FD&C Act, 21 U.S.C. § 360b(a)(2), and adulterated under section 501(a)(6) of the FD&C Act, 21 U.S.C. § 351(a)(6). Section 512 of the FD&C Act, 21 U.S.C. § 360b, and 21 C.F.R. 530.11(b) do not permit the extralabel use of medicated feed.

The above is not intended to be an all-inclusive list of violations. As a producer of animals offered for use as food, you are responsible for ensuring that your overall operation and the food you distribute is in compliance with the law.

You should take prompt action to correct the violations described in this letter and to establish procedures to ensure that these violations do not recur. Failure to do so may result in regulatory action without further notice such as seizure and/or injunction.

You should notify this office in writing of the steps you have taken to bring your firm into compliance with the law within fifteen (15) working days of receiving this letter.

Your response should include each step that has been taken or will be taken to correct the violations and prevent their recurrence. If corrective action cannot be completed within fifteen (15) working days of receiving this letter, state the reason for the delay and the time frame within which the corrections will be completed. Please include copies of any available documentation demonstrating that corrections have been made.

Your written response should be sent to Allison C. Hunter, Compliance Officer, U.S. Food and Drug Administration, 6751 Steger Drive, Cincinnati, Ohio 45237. If you have any questions about this letter, please contact Compliance Officer Hunter at 513-679-2700 ext. 134.

Sincerely yours, /S/

Teresa Thompson District Director Cincinnati District


http://www.fda.gov/ICECI/EnforcementActions/WarningLetters/2011/ucm248212.htm




p.s. update prion disease ;




Sunday, May 01, 2011

STUDY OF ATYPICAL BSE 2010 Annual Report May 2011

http://bse-atypical.blogspot.com/2011/05/study-of-atypical-bse-2010-annual.html




Saturday, March 5, 2011

MAD COW ATYPICAL CJD PRION TSE CASES WITH CLASSIFICATIONS PENDING ON THE RISE IN NORTH AMERICA

http://transmissiblespongiformencephalopathy.blogspot.com/2011/03/mad-cow-atypical-cjd-prion-tse-cases.html




TSS

EFSA publishes results of the first survey on MRSA in pigs in the EU

Press Release 24 November 2009 EFSA publishes results of the first survey on MRSA in pigs in the EU

The European Food Safety Authority (EFSA) has published the first EU-wide survey on MRSA (Methicillin-resistant Staphylococcus aureus) in breeding pigs. The results indicate that MRSA, a bacterium resistant to many antibiotics, is commonly detected in holdings with breeding pigs in some EU Member States. The survey provides estimates of its occurrence and makes recommendations for further monitoring and investigation of the causes and implications of MRSA findings in pig holdings in the EU. The survey was carried out in 24 Member States[1], 17 of which found some type of MRSA in their holdings with breeding pigs and 7 none at all. On average, different types of MRSA were found in 1 out of 4 holdings with breeding pigs across the EU, but the survey also says that figures vary greatly between Member States. MRSA ST398 was the most reported type of MRSA among the holdings with breeding pigs in the EU; some Member States also reported other types, but their prevalence was much lower[2].

MRSA is a major concern for public health and its various types are recognised as an important cause of hospital-acquired (or nosocomial) infections in humans. The specific type MRSA ST398 has been identified in some domestic animals and is considered an occupational health risk for farmers, veterinarians and their families, who may become exposed to it through direct or indirect contact with these animals. In an opinion published earlier this year, EFSA’s Biological Hazards (BIOHAZ) Panel assessed the public health significance of MRSA in animals and food[3] and concluded that the MRSA ST398[4] strain is less likely to contribute to the spread of MRSA in hospitals than other types carried by humans. The Panel also said that there is currently no evidence that MRSA ST398 can be transmitted to humans by eating or handling contaminated food.

In the survey published today, EFSA recommends monitoring of pigs and other food producing animals for MRSA. It also says further research should be carried out, so that the reasons for differences in the prevalence of MRSA in the various Member States can be identified and used to propose options on possible control measures.

_________________________________________ Note to editors:

The Staphylococcus aureus is a bacterium that can be persistently or intermittently carried by healthy humans and is a very common cause of minor skin infections that usually do not require treatment. In patients in hospitals, Staphylococcus aureus is a common cause of hospital-acquired infections. Its variant Methicillin-Resistant Staphylococcus aureus (MRSA) emerged in the 1970s and is now often found in hospitals in many European Member States. MRSA is resistant to many commonly used antibiotics. In recent years, clones of MRSA have evolved outside the hospitals, causing infections among people who have no connection with hospitals. Most recently MRSA has also been detected in several farm animal species.

EFSA’s Zoonoses Unit monitors and analyses the situation on zoonoses, zoonotic agents, antimicrobial resistance, microbiological contaminants and food-borne outbreaks across Europe. The Unit is supported by a Task Force on Zoonoses Data Collection consisting of a pan-European network of national representatives of Member States, other reporting countries, as well as World Health Organisation (WHO) and World organisation for animal health (OIE). They gather each year data in their respective countries.

EFSA’s BIOHAZ Panel provides scientific advice on biological hazards in relation to food safety and food-borne diseases. This covers food-borne zoonoses (animal diseases transmissible to humans), Transmissible spongiform Encephalopathies (BSE/TSEs), food microbiology, food hygiene and associated waste management issues. The Panel’s risk assessment work helps to provide a sound foundation for European policies and legislation and supports risk managers in taking effective and timely decisions.

Analysis of the baseline survey on the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in holdings with breeding pigs, in the EU, 2008 [1] - Part A: MRSA prevalence estimates

EFSA’s previous work on MRSA:

EFSA’s BIOHAZ Panel “Assessment of the Public Health significance of Methicillin-resistant Staphylococcus aureus (MRSA) in animals and foods” Joint scientific report of ECDC, EFSA and EMEA on Methicillin-resistant Staphylococcus aureus (MRSA) in livestock, companion animals and food

Joint Opinion of ECDC, EFSA, EMEA and SCENIHR on antimicrobial resistance (AMR) focused on zoonotic infections

--------------------------------------------------------------------------------

[1] The sampling took place during 2008. Dust samples were taken in the environment of pigs in a total of 5,073 holdings from 24 EU Member States and two non-Member States. The pooled sample of each holding was tested for the presence of the various MRSA strains. [2] Only six Member States and one non-Member State reported MRSA non-ST398 in the holdings with breeding pigs. The prevalence of MRSA non-ST398 in holdings with breeding pigs across the participating Member States was substantially lower than the prevalence of MRSA and MRSA ST398. [3] EFSA’s BIOHAZ Panel opinion on the “Assessment of the Public Health significance of Methicillin-resistant Staphylococcus aureus (MRSA) in animals and foods” of March 2009 [4] In its opinion the BIOHAZ Panel refers to CC398 which corresponds to MRSA ST398.



http://www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1211903070258.htm



http://staphmrsa.blogspot.com/




TSS

Methicillin-Resistant Staphylococcus aureus (MRSA) Strain ST398 Is Present in Midwestern U.S. Swine and Swine Workers

Methicillin-Resistant Staphylococcus aureus (MRSA) Strain ST398 Is Present in Midwestern U.S. Swine and Swine Workers

Tara C. Smith1,2*, Michael J. Male1,2, Abby L. Harper1,2, Jennifer S. Kroeger3, Gregory P. Tinkler2, Erin D. Moritz1,2, Ana W. Capuano1,2, Loreen A. Herwaldt1,3,4, Daniel J. Diekema3,4,5

1 Department of Epidemiology, University of Iowa College of Public Health, Iowa City, Iowa, United States of America, 2 Center for Emerging Infectious Diseases, University of Iowa College of Public Health, Iowa City, Iowa, United States of America, 3 Department of Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America, 4 Program of Hospital Epidemiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States of America, 5 Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America

Abstract Background Recent research has demonstrated that many swine and swine farmers in the Netherlands and Canada are colonized with MRSA. However, no studies to date have investigated carriage of MRSA among swine and swine farmers in the United States (U.S.).

Methods We sampled the nares of 299 swine and 20 workers from two different production systems in Iowa and Illinois, comprising approximately 87,000 live animals. MRSA isolates were typed by pulsed field gel electrophoresis (PFGE) using SmaI and EagI restriction enzymes, and by multi locus sequence typing (MLST). PCR was used to determine SCCmec type and presence of the pvl gene.

Results In this pilot study, overall MRSA prevalence in swine was 49% (147/299) and 45% (9/20) in workers. The prevalence of MRSA carriage among production system A's swine varied by age, ranging from 36% (11/30) in adult swine to 100% (60/60) of animals aged 9 and 12 weeks. The prevalence among production system A's workers was 64% (9/14). MRSA was not isolated from production system B's swine or workers. Isolates examined were not typeable by PFGE when SmaI was used, but digestion with EagI revealed that the isolates were clonal and were not related to common human types in Iowa (USA100, USA300, and USA400). MLST documented that the isolates were ST398.

Conclusions These results show that colonization of swine by MRSA was very common on one swine production system in the midwestern U.S., suggesting that agricultural animals could become an important reservoir for this bacterium. MRSA strain ST398 was the only strain documented on this farm. Further studies are examining carriage rates on additional farms.

Citation: Smith TC, Male MJ, Harper AL, Kroeger JS, Tinkler GP, et al. (2008) Methicillin-Resistant Staphylococcus aureus (MRSA) Strain ST398 Is Present in Midwestern U.S. Swine and Swine Workers. PLoS ONE 4(1): e4258. doi:10.1371/journal.pone.0004258

Editor: Ulrich Dobrindt, University of Würzburg, Germany

Received: October 9, 2008; Accepted: December 19, 2008; Published: January 23, 2008

Copyright: © 2009 Smith et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: This study was funded with departmental startup funds (TCS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

* E-mail: tara-smith@uiowa.edu

Introduction ...snip...end

see full text ;


http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0004258


MRSA

http://staphmrsa.blogspot.com/