No abstract

During an 18-month period in a burn center (January 1995 through June 1996), 109 single-patient MRSA isolates were identified and 102 isolates (94%) were available for DNA fingerprinting. Ninety-nine isolates (97%) carried the mecA polymorph I and Tn554 type E. Pulsed-field electrophoresis (PFGE) identified 8 patterns, of which 60 isolates were of pattern F2. The I:E:F clonal type and a stable drug multidrug resistant phenotype (sensitivity only to trimethoprim/sulfamethoxazole and vancomycin) indicated that these isolates were closely related to the Iberian clone of MRSA, which is widely spread in Europe. The initial source of I:E:F isolates was sputum 49%, blood 23%, wound 16%, urine 7%, and intravascular catheter tip 5%. Fifty-four percent of patients had smoke inhalation injury, and 51/53 required intubation or tracheostomy. Forty-three isolates were considered invasive (positive blood culture). The overall mortality was 30%. Despite infection control measures, the I:E:F clone continued to be recovered from patients during the 18 months of study. This outbreak is the first known report of the Iberian MRSA clone in the United States.

S. marcescens causes significant morbidity and mortality in preterm neonates. Cross-transmission via transient hand carriage of a HCW appeared to be the probable route of transmission in NICU A. Sinks did not harbor the outbreak strains. Antimicrobial susceptibility patterns did not prove to be an accurate predictor of strain relatedness for S. marcescens.