Hyang Soon Oh

Investigation and control of an outbreak of imipenem-resistant Acinetobacter baumannii Infection in a Pediatric Intensive Care Unit.

Background: This study investigated the clinical details and epidemiology of the imipenem-resistant Acinetobacter baumannii (IRAB) outbreak that occurred at a pediatric intensive care unit (PICU), and describes successful outcome of the implemented infection control measures. Methods: With the recognition of 3 clustered cases with IRAB bacteremia at the PICU of Seoul National University Children’s Hospital, Korea, from August to September 2010, the following outbreak control strategies were implemented: reinforcement of hand hygiene and contact precautions, investigation of environmental contamination, disinfection of the contaminated environment and medical equipment, active surveillance culture upon PICU admission and isolation of IRAB-positive patients. The clinical and microbiological data were reviewed for A. baumannii positive cases in the PICU from April 2001 to June 2011. Multilocus sequence typing was also performed. Results: Twenty IRAB-positive cases (bacteremia in 10, pneumonia in 3 and colonizers in 7) were detected from January 2010 to February 2011. Thirteen IRAB-infected patients were all placed on a mechanical ventilator, had central venous catheters, received broad-spectrum antimicrobial treatment and had underlying diseases. Eleven (85%) IRAB-infected patients died probably due to IRAB infection. IRAB grew in 4 samples obtained from sinks and water taps from 38 environmental samples. Multilocus sequence typing analysis revealed 2 sequence types: ST138 (n = 16) and its single-locus variant ST92 (n = 4). Eleven weeks after the initiation of active surveillance, no further IRAB isolates were identified. Conclusions: This study identifies the environmental source of an IRAB outbreak in a PICU and describes successful control of the outbreak with a multicomponent intervention program.

Outbreak of vancomycin resistant Enterococcus in a hematology/oncology unit in a Korean University Hospital, and risk factors related to patients, staff, hospital care and facilities

A vancomycin-resistant Enterococcus (VRE) outbreak occurred at a hematology/oncology (HO) service in a tertiary acute care hospital, 1 January to 30 April 2002. This study was undertaken to identify risk factors, and to establish relations between seasonal factors and this VRE outbreak. Every patient (n=82) and health care worker (HCW) (n=31) at the HO unit was screened by rectal swab and stool culture during the VRE outbreak. Environmental surface culture (n=35) and pulsed-field gel electrophoresis (PFGE) of VRE isolates were preformed. Among a total of 82 patients, 17 had VRE. All VRE isolates were E. faecium, the 6 studied further were Van A with identical PFGE patterns. Cultures of surfaces and HCWs were negative for VRE. Prolonged hospital stay (p=0.02), male gender (p=0.02), and care in a 6-bed room (p<0.01) were risk factors for acquisition of VRE. An association with the VRE outbreak period was found again for long hospital stay, but also for the antibiotic usage pattern, frequent surgery and a high proportion of new inexperienced staff (52% vs 4% before the outbreak (p<0.01, Fishers exact test). Sudden personnel turnover in high-risk units should be avoided.