Outbreak of nosocomial sepsis in NICU by multidrug-resistant Klebsiella pneumoniae: Diagnostic challenges

Purpose: Nosocomial infections are a serious problem in neonatal intensive care units (NICU) – they are one of the main causes of morbidity and mortality among preterm newborns.
Material/methods: We present a prospective clinical-epidemiological study of an outbreak of 7 cases of culture-proven multidrug-resistant (MDR) Klebsiella pneumoniae late onset sepsis in a period of 2 months in a tertiary level NICU in Pleven, Bulgaria. The risk factors, early clinical presentation, laboratory changes, course of infection, treatment, and outcome were evaluated.
Results: Three of our patients were term infants, the other four patients were preterm aged from 25 to 36 gestational weeks. The most possible routs of transmission of the infection were: venous lines, mechanical ventilation, tube feeding. Аll of the mentioned were present in one extremely immature patient.
Early clinical signs included skin color changes, abnormal muscle tone, respiratory failure. Laboratory tests taken at the time of onset revealed leucopenia and/or thrombocytopenia in a half of the cases and usually C-reactive protein remained normal, but in all cases the I/T ratio increased significantly. The clinical course varied from fulminant deterioration to easily controlled condition. Treatment with Meropenem was started at the time of clinical suspicion of infection, according to the antibiogram of the first cases. No fatal outcome was observed.
Conclusion: Main causes for the outbreak of hospital acquired infection were overcrowding of the NICU, admission of patients from lower-level hospitals, insufficient working staff, especially midwifes. The early diagnosis and proper antimicrobial treatment were crucial for the favorable outcome.