There is other evidence of human to human spread. The results below may simply reflect good infection control.
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.
