An outbreak of vancomycin-resistant Enterococcus faecium in an acute care pediatric hospital: Lessons from environmental screening and a case-control study.

BACKGROUND: The present study describes a vancomycin-resistant enterococci (VRE) outbreak investigation and a case-control study to identify risk factors for VRE acquisition in a tertiary care pediatric hospital. OBJECTIVE: To report an outbreak investigation and a case-control study to identify risk factors for VRE colonization or infection in hospitalized children. METHODS: Screening for VRE cases was performed by culture or polymerase chain reaction. A case-control study of VRE-colonized patients was undertaken. Environmental screening was performed using standard culture and susceptibility methods, with pulsed-field gel electrophoresis to determine relationships between VRE isolates. Statistical analysis was performed using SAS version 9.0 (SAS Institute Inc, USA). RESULTS: Thirty-four VRE-positive cases were identified on 10 wards between February 28, 2005, and May 27, 2005. Pulsed-field gel electrophoresis analysis confirmed a single outbreak strain that was also isolated from a video game found on one affected ward. Multivariate analysis identified cephalosporin use as the major risk factor for VRE colonization. CONCLUSIONS: In the present study outbreak, VRE colonization was significantly associated with cephalosporin use. Because shared recreational items and environmental surfaces may be colonized by VRE, they warrant particular attention in housekeeping protocols, particularly in pediatric institutions.

Sustained endemicity of Burkholderia cepacia complex in a pediatric institution, associated with contaminated ultrasound gel.

OBJECTIVE: To determine whether contaminated ultrasound gel is the source of intermittent outbreaks of nosocomial infection due to Burkholderia cepacia complex in patients without cystic fibrosis since 1992. DESIGN: A prospective clinical and in vitro study of all in-use bottles of ultrasound gel, as well as a retrospective analysis of archived bacterial strains, were performed. Handling of gel for clinical purposes throughout the hospital was evaluated. Gel and archived clinical isolates of B. cepacia complex were speciated to genomovar level and characterized by pulsed-field gel electrophoresis, and the pulsed-field gel electrophoresis patterns were compared. SETTING: The Hospital for Sick Children, a 300-bed, tertiary care, pediatric academic health sciences center in Toronto, Canada. PATIENTS: All patients without cystic fibrosis from whom B. cepacia complex was recovered at the Hospital for Sick Children since 1992. RESULTS: No standardized protocol for storage or handling of ultrasound gel was found. Gel from 39% of bottles grew either B. cepacia (genomovar I) or Burkholderia stabilis (genomovar IV). These isolates had pulsed-field gel electrophoresis patterns identical to 2 of the 7 clinical pulsed-field gel electrophoresis types that are responsible for 88% of clinical isolates. CONCLUSIONS: Contaminated ultrasound gel contributed to nosocomial infection due to B. cepacia complex in this institution over the course of 10 years. Suggested guidelines for the handling of ultrasound gel are provided.

Enteral tube hub as a reservoir for transmissible enteric bacteria.

Enteral feeding is a risk factor for cross transmission of microbes. Administration set tubing can be colonized by organisms present in the enteral tube hub; molecular typing has demonstrated genetic relatedness of enteric bacteria isolated from both sites. Strict attention to infection control measures is imperative when handling enteral feed apparatuses.

Microbial contamination of enteral feed administration sets in a pediatric institution.

BACKGROUND: Enteral feeding tubes have been associated with outbreaks of antimicrobial-resistant organisms, but the pathogenesis of this association has not been investigated. We hypothesized that the enteral feed administration sets become colonized externally by microbes grown from the enteral tube hub, and therefore serve as a reservoir of organisms that can be crosstransmitted. METHODS: We conducted a prospective observational cohort pilot study, obtaining bacterial cultures from the external enteral feed administration set and from the hub of nasogastric, gastric, or gastrojejunal tubes in children receiving enteral feeding while hospitalized in a tertiary care pediatric hospital. RESULTS: Thirty-six of 37 hubs cultured had bacterial growth. Twenty-nine of 36 administration sets (78%) sampled had at least 1 microbe isolated that was also cultured from the hub. No significant risk factors for colonization were identified. CONCLUSIONS: Enteral feed administration sets are frequently colonized by organisms in the enteral tube hub. These sets can serve as a reservoir of organisms that can be crosstransmitted between patients. Adherence to Standard Precautions is critical when handling enteral feeding apparatuses.

Do in-line respiratory filters protect patients? Comparing bacterial removal efficiency of six filters.

With all pulmonary function diagnostic and respiratory therapy equipment, cross-infection has always been a concern, especially in the cystic fibrosis population, in whom pulmonary function tests are done routinely. The aim of this study was to identify and compare the bacterial removal efficiency (BRE, ability of a filter to remove microorganisms) of six different filters used in hospital settings: Microgard (MG), Spirobac (SB), PALL (PL), and KOKO (KK), used in the pulmonary function laboratory; and Clear-Guard (CG) and Respigard (RG), used in ventilator circuits. Filters were tested in both saturated and nonsaturated conditions. A Pseudomonas aeruginosa suspension of 1 x 10(4) to 1 x 10(8) CFU/mL was nebulized onto each filter. A blood agar plate was held immediately downstream from the filter. Colony-forming units (CFU) were then counted after 24 hr of incubation. A peak flow was applied across the spirometry filters. Bacterial thresholds of the filters were also identified (concentration of bacteria at which a filter no longer has 100% BRE). There was a significant difference in BRE among the six filters in saturated states when challenged with 1 x 10(4) CFU/mL (MG, KK, CG, and RG, 100%; SB, 98.8%; PL, 42.7%; P = 0.003). There was no significant difference between saturated and nonsaturated states, or after application of a peak flow. Filter thresholds were significantly different (KK 1 x 10(8), MG 1 x 10(7), CG 1 x 10(6), RG 1 x 10(5), and SB and PL <1 x 10(4) CFU/mL). In conclusion, when all filters are exposed to the same extreme challenges, significant differences exist in their ability to remove bacteria.

Nosocomial transmission of group B streptococci proven by positive environmental culture.

OBJECTIVE: Neonates usually acquire Group B streptococcal infection vertically from the maternal birth canal during delivery. In January 2010, a Group B streptococcal outbreak investigation was conducted in response to an increased number of clinical specimens from our neonatal intensive care unit. METHODS: Microbiology laboratory records were reviewed to identify Group B streptococcal from specimens originating from the neonatal intensive care unit during December 2009 and January 2010. Patients from whom these specimens were collected were identified and their charts reviewed. Environmental samples to screen for Group B streptococcal were collected from the unit, clinical and environmental isolates were compared by pulsed field gel electrophoresis. Point prevalence screening was conducted twice before declaring the outbreak over. RESULTS: Pulsed field gel electrophoresis patterns of three clinical strains from six patients were indistinguishable. One environmental strain was isolated from one of the patients monitor, and had identical pulsed field gel electrophoresis pattern to that of the three clinical strains. Infection control measures were implemented in the neonatal intensive care unit and follow-up point prevalence screening identified no new cases. CONCLUSIONS: Although poor infection control practice has been implicated in previous reports of nosocomial outbreaks of Group B streptococcal infection in neonatal intensive care units, our finding provides unique evidence that the environment can act as a reservoir of Group B streptococcal and play a key role in nosocomial transmission.