Overall, almost 16% of the study participants, who lived and worked on veal calf farms, carried MRSA. By comparison, the prevalence of MRSA in the Dutch community is estimated to be 1%.

The prevalence of MRSA among the calves was almost double that of the people studied, with 28% of the 2150 calves tested found to be carrying the bug. Almost all these bacteria were of the ST398 strain, and MRSA was more often found in calves that had been treated with antibiotics.

“This is the strongest evidence of a direct relationship between antibiotic use in animals and transfer of antimicrobial resistant organisms to humans at present,” write Graveland and colleagues.

via News.

Objectives: To determine the transmission rate of animal-related ST398 MRSA and other MRSA isolates within Dutch hospitals.

Methods: Data were collected in 51 Dutch hospitals from July 2006 to January 2007. An index patient was defined as a carrier of MRSA (not necessarily infected) that was treated in a hospital without transmission precautions. As part of the Dutch MRSA policy all possible contact patients and healthcare workers (HCW) are screened for MRSA after identification of an index patient.

Results: During 306 months of observation, there were 80 index patients: 24 ST398 and 56 with other MRSA genotypes. Other genotypes included typical hospital-associated genotypes, but not USA300. In 80 clinical post-exposure surveys 2134 patients and 5758 HCWs were screened for MRSA. ST398 MRSA carriage was found in 3 HCWs (0.3% of all screened HCWs) as compared to 62 secondary cases with other MRSA genotypes (0.6% of screened HCWs; 1.7% of screened contact patients). No transmission of ST398 MRSA to screened contact patients (n = 383) was documented. Index patients carrying ST398 MRSA had been hospitalised shorter before isolation measures were taken than carriers of other MRSA genotypes (median respectively 1.5 and 4 days; p = 0.04); the number of contacts screened per day of exposure, however, did not differ between both groups (p = 0.75). The risk of transmission of ST398 MRSA per day of exposure was 25% of the risk of spread of the other MRSA genotypes (95% CI = 0.08 to 0.78; p = 0.01).

Conclusion: During 306 hospital-months the risk of transmission of pig-related ST398 MRSA was lower than that of other MRSA genotypes. Not a single documented case of patient-to-patient spread was found.

European Society of Clinical Microbiology and Infectious Diseases.

The main objective of the present study was to investigate if different kinds of pig farms, like farrowing farms and rearing farms, play a role in the transmission of methicillin-resistant Staphylococcus aureus (MRSA) to Dutch finishing farms. Twelve farrowing farms, 11 finishing farms, 6 farrow-to finish farms, 1 rearing farm and 1 centre for artificial insemination were included. Screening of 310 pigs from these 31 farms showed 35 pigs (11%) to carry MRSA in their nares. On 7 of the 31 (23%) investigated farms colonized pigs were found, including 3 finishing farms, 3 farrowing farms and 1 farrow-to-finish farm. The use of standard antimicrobial medication of the pigs seemed to be a risk factor for MRSA carriage. Screening of the pigs on six farms supplying pigs for the MRSA positive farms revealed that the pigs on all but one farm were MRSA positive. Genotyping revealed that all MRSA strains were non-typeable by PFGE using the SmaI restriction enzyme and had multilocus sequence type (MLST) ST398. Different spa-types were found including t011, t108, t567, t899 and t1939, but the spa-types on epidemiologically related farms were identical indicating that MRSA are transmitted between farms through the purchase of colonized pigs.

Transmission of methicillin-resistant Staphylococc…[Vet Microbiol. 2008] – PubMed Result.

A 63-year-old woman with a kidney transplant was admitted with endocarditis caused by meticillin-resistant Staphylococcus aureus (MRSA). Once her antibiotic therapy had been adjusted to the sensitivity-pattern of the bacterial strain she recovered, without the need for surgical intervention. The isolated S. aureus was typed by multi-locus sequence typing as sequence type 398, a MRSA-strain that has recently been isolated from a high percentage of Dutch pigs. This is the first report of a life-threatening infection with this pig MRSA. This strain is genetically different from the globally dispersed nosocomial MRSA-strains, and also from the strains that have been epidemic for several years in the USA as the causative agent ofcommunity-acquired skin infections. The Dutch Working Group on Infection Prevention (WIP) has recently adjusted its guidelines to halt further spread of this strain, and advises that the population at risk (pig breeders, slaughterhouse personnel and veterinarians) be held in isolation when hospitalised until MRSA colonisation has been excluded. The patient described here, however, did not belong to this population at risk.

[Endocarditis due to meticillin-resistant Staphylo...[Ned Tijdschr Geneeskd. 2006] – PubMed Result.

In The Netherlands, patients exposed to pigs or veal calves were recently shown to be at high risk of methicillin-resistant Staphylococcus aureus (MRSA) carriage. In Amphia Hospital (Breda, The Netherlands), 32% of patients in this risk group were shown to carry MRSA. This resulted in a 3-fold increase in the annual MRSA incidence.

Increase in a Dutch hospital of methicillin-resist…[Clin Infect Dis. 2008] – PubMed Result.

In 2003 in the Netherlands, a new methicillin-resistant Staphylococcus aureus (MRSA) strain emerged that could not be typed with Sma1 pulsed-field gel electrophoresis (NT-MRSA). The association of NT-MRSA in humans with a reservoir in animals was investigated. The frequency of NT-MRSA increased from 0% in 2002 to >21% after intensified surveillance was implemented in July 2006. Geographically, NT-MRSA clustered with pig farming. A case-control study showed that carriers of NT-MRSA were more often pig or cattle farmers (pig farmers odds ratio [OR] 12.2, 95% confidence interval [CI] 3.1-48.6; cattle farmers OR 19.7, 95% CI 2.3-169.5). Molecular typing showed that the NT-MRSA strains belonged to a new clonal complex, ST 398. This study shows that MRSA from an animal reservoir has recently entered the human population and is now responsible for >20% of all MRSA in the Netherlands.

Emergence of methicillin-resistant Staphylococcus …[Emerg Infect Dis. 2007] – PubMed Result.

Three family members, three co-workers, and 8 of the 10 pigs were MRSA positive. With the exception of the initial case (the mother) all persons were solely colonized, with no signs of clinical infections. After digestion with SmaI, none of the strains showed any bands using PFGE. All isolates belonged to spa type t108 and ST398. CONCLUSION: 1. This report clearly shows clonal spread and transmission between humans and pigs in the Netherlands. 2. MLST sequence type 398 might be of international importance as pig-MRSA, since this type was shown earlier to be present in epidemiologically unrelated French pigs and pig-farmers. 3. Research is needed to evaluate whether this is a local problem or a new source of MRSA, that puts the until now successful Search and Destroy policy of the Netherlands at risk.

Community-acquired MRSA and pig-farming. [Ann Clin Microbiol Antimicrob. 2006] – PubMed Result.

Of the 498 new MRSA patients identified (65% with screening; 35% unexpected carriers) 31% carried ST398 MRSA (92% detected through screening). The overall prevalence of MRSA in the screened population was 3.6% (95%-BI: 3.2-4.0). Prevalence were 2.5% (95%-BI: 1.9-3.1), 3.8% (95%-BI: 3.1-4.5; p=0.007) and 4.6% (95%-BI: 3.7-5.5; p=0.000), respectively, in low, moderate and high pig density region hospitals. Prevalence of ST398 MRSA was 12.4% in patients screened in hospitals in regions with a high or moderate pig density and 0% in hospitals in regions with a low pig density. The prevalence of other MRSA isolates in patients screened in these hospitals was between 1.1 – 2.9%. In post-exposure screenings, unrelated ST398 MRSA carriers (index case had different genotype) were found in 0.06% (3/4794) of HCWs and none of the patients (0/1951). Other MRSA isolates (genotype different from index case and excluding ST398) were detected in 0.1% (8/5758) of HCWs and 0.5% (10/2134) of patients.

Conclusion: In this first large survey of ST398 MRSA in Dutch hospitals we found that MRSA is more prevalent in regions with a high or moderate pig density, solely because of an increase of ST398 MRSA. Almost 80% of new carriers are detected in out-patient departments and 92% because of active surveillance. ST398 MRSA colonization is rarely encountered in HCWs and patients during post-exposure screenings of index cases with different genotypes.

Abstractverwaltung AKM AG.