Friday, 23 January 2009

MRSA in Iowa pigs and pig workers

A ten year battle is now almost over for the writer. MRSA has been detected in significant numbers of US pigs and pig workers. He did his best to stop this happening.

Britain still refuses to release the results of testing her pigs.

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.).

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.

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.

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