Endemic Serratia marcescens in a neonatal intensive care unit.

OBJECTIVE: To study the endemicity of Serratia marcescens in a neonatal intensive care unit (N.I.C.U). MATERIAL AND METHOD: During the first 4 months of 2001, neonates in the N.I.C.U. in a teaching hospital were screened for S. marcescens by serial throat swabs and collections of other appropriate clinical specimens. Environmental cultures were also done in the same period. Isolated S. marcescens were tested for antimicrobial susceptibility and for genotyping by pulsed field gel electrophoresis. RESULTS: During the period, 104 neonates were studied. S. marcescens were isolated in 34.6% of the cases. Environmental cultures were positive for S. marcescens in 1.4%. There were 10 patterns of antibiogram of the 190 strains isolated. All strains belonged to pulsotype A. CONCLUSION: The study confirmed that S. marcescens was endemic in the N.I.C.U. and belonged to one genotype.

The first pediatric case of Staphylococcus aureus with heterogenous resistant to vancomycin endocarditis in Thailand.

Staphylococcus aureus with reduced susceptibility to vancomycin has been reports worldwide. Here we report the first pediatric case of heterogeneous vancomycin intermediate resistance Staphylacoccus aureus (hVISA) causing endocarditis in Thailand. A 4 months old girl with truncus arteriosus type IV and ventricular septal defect developed methicillin-resistant S. aureus (MRSA) bacteremia and endocarditis after total repair operation. The patient did not respond to combination antimicrobial treatment including vancomycin. The strain was susceptible to trimethoprim-sulfamethoxazole and vancomycin by conventional antimicrobial susceptibily test. The vancomycin minimal inhibitory concentration by E-test was 2 microg/ml. The strain was judged to be possible heteroresistant when screening was done by one-point population analysis. The subsequent population analysis and testing for the emergence of mutants with reduced susceptible to vancomycin confirmed that this strain was hVISA. Despite the treatment with vancomycin, amikacin, rifampicin and cotrimoxazole, the patient died. hVISA should be suspected in MRSA infections that were refractory to vancomycin therapy could be due to. The emergence hVISA underscored the importance of the prudent use of antibiotics, the laboratory capacity to identify MRSA and hVISA and proper communication with treating clinicians, and the meticulous infection-control measures to prevent transmission.