Comparison of transmission rates of MRSA and 3MDR-GN E. coli during the two study intervals

Study intervalPathogen (no. of isolates/total no. of patient cases/no. of cases at risk wards)No. of genotypic clusters (maximal distance for cluster recognition)Epidemiological assessment of genotypic clustersTotal no. of cases involved in probable transmissions (%)No. of cases in risk wards with changed infection control procedures for 3MDR-GN (%) during interval II
IMRSA (412/397/68)32 (≤6 alleles)8 clusters with probable transmissions, 16 clusters with unlikely transmissions, isolation 8 times from same patient but different colony morphology/phenotype results23 (5.8)15 (22.1)
E. coli (102/86/51)13 (≤10 alleles)1 cluster with probable transmission, 1 cluster with unlikely transmissions, isolation 11 times from same patient but different cases/colony morphology/phenotype results2 (2.3)2 (3.9)
IIMRSA (325/325/57)15 (≤6 alleles)6 clusters with probable transmissions, 9 clusters with unlikely transmissions14 (4.3)6 (10.5)a
E. coli (120/120/45)8 (≤10 alleles)1 cluster with probable transmissions, 7 clusters with unlikely transmissions6 (5.0)0 (0)a
  • a Results of comparisons of transmission rates between interval I and II were not statistically significant for MRSA (P = 0.0980) or MDR E. coli (P = 0.4967).