Pseudomonas aeruginosa outbreak in a pediatric intensive care unit linked to a humanitarian organization residential center.

BACKGROUND: Pseudomonas aeruginosa commonly colonizes the hospital environment. Between April 2006 and September 2008, we investigated an outbreak of P. aeruginosa infection occurring in a pediatric intensive care unit. We conducted epidemiologic and molecular investigations to identify the source of the outbreak. METHODS: Retrospective case finding; surveillance cultures of patients and environmental sites; admission screening; case-control study; and molecular typing. PATIENT AND SETTING: Infants and children in a pediatric intensive care unit of a tertiary-care institution. RESULTS: Thirty-seven cases of P. aeruginosa infection or colonization were detected between April 2006 and September 2008, including 3 fatal bloodstream infections. A closely-related strain was detected in 4 residents of a humanitarian nongovernmental organization (NGO) center who developed an infection, from 4 additional residents upon their hospital admission, and from a sink drain at the NGO residential center. NGO recipients represented 65% (24/37) of the total number of cases of P. aeruginosa colonization or infection during the outbreak period. Investigation at the residential center showed widespread contamination of the sewage system (10/14 sinks and shower drains, 70%) and a high prevalence (38%) of P. aeruginosa carriage among children. CONCLUSIONS: These findings suggest that the probable cause of the outbreak was the contamination of the NGO residential center with further nosocomial transmission after admission, and highlight the importance of considering external sources when investigating hospital outbreaks.

Reduction of health care associated infection risk in neonates by successful hand hygiene promotion.

OBJECTIVES: Hand hygiene promotion interventions rarely result in sustained improvement, and an assessment of their impact on individual infection risk has been lacking. We sought to measure the impact of hand hygiene promotion on health care worker compliance and health care-associated infection risk among neonates. METHODS: We conducted an intervention study with a 9-month follow-up among all of the health care workers at the neonatal unit of the Children's Hospital, University of Geneva Hospitals, between March 2001 and February 2004. A multifaceted hand hygiene education program was introduced with compliance assessed during successive observational surveys. Health care-associated infections were prospectively monitored, and genotypic relatedness of bloodstream pathogens was assessed by pulsed-field gel electrophoresis. A comparison of observed hand hygiene compliance and infection rates before, during, and after the intervention was conducted. RESULTS: A total of 5325 opportunities for hand hygiene were observed. Overall compliance improved gradually from 42% to 55% across study phases. This trend remained significant after adjustment for possible confounders and paralleled the measured increase in hand-rub consumption (from 66.6 to 89.2 L per 1000 patient-days). A 9-month follow-up survey showed sustained improvement in compliance (54%), notably with direct patient contact (49% at baseline vs 64% at follow-up). Improved compliance was independently associated with infection risk reduction among very low birth weight neonates. Bacteremia caused by clonally related pathogens markedly decreased after the intervention. CONCLUSIONS: Hand hygiene promotion, guided by health care workers' perceptions, identification of the dynamics of bacterial contamination of health care workers' hands, and performance feedback, is effective in sustaining compliance improvement and is independently associated with infection risk reduction among high-risk neonates.

Outbreak of endophthalmitis after cataract surgery: the importance of the quality of the surgical wound.

Postoperative endophthalmitis is a rare but potentially devastating condition. We investigated an outbreak of 8 cases of endophthalmitis in patients who underwent phakectomy performed by a single surgeon from January through September 2004. The outbreak was traced to damaged surgical blades, and it highlights the importance of the quality of the surgical wound.

Evidence-based model for hand transmission during patient care and the role of improved practices.

Hand cleansing is the primary action to reduce health-care-associated infection and cross-transmission of antimicrobial-resistant pathogens. Patient-to-patient transmission of pathogens via health-care workers' hands requires five sequential steps: (1) organisms are present on the patient's skin or have been shed onto fomites in the patient's immediate environment; (2) organisms must be transferred to health-care workers' hands; (3) organisms must be capable of surviving on health-care workers' hands for at least several minutes; (4) handwashing or hand antisepsis by the health-care worker must be inadequate or omitted entirely, or the agent used for hand hygiene inappropriate; and (5) the caregiver's contaminated hand(s) must come into direct contact with another patient or with a fomite in direct contact with the patient. We review the evidence supporting each of these steps and propose a dynamic model for hand hygiene research and education strategies, together with corresponding indications for hand hygiene during patient care.

Use of oligoarrays for characterization of community-onset methicillin-resistant Staphylococcus aureus.

Until recently, methicillin-resistant Staphylococcus aureus (MRSA) was considered the prototype of a hospital-acquired bacterial pathogen. However, recent reports have shown that MRSA has now emerged in the community. Characterization of specific markers for distinguishing the origin of isolates could contribute to improved knowledge of MRSA epidemiology. The release of whole-genome sequences of hospital- and community-acquired S. aureus strains allowed the development of whole-genome content analysis techniques, including microarrays. We developed a microarray composed of 8,191 open reading frame-specific oligonucleotides covering >99% of the four sequenced S. aureus genomes (N315, Mu50, MW2, and COL) to evaluate gene contents of hospital- and community-onset S. aureus strains. In parallel, pulsed-field gel electrophoresis, variable number of tandem repeats, antibiogram, staphylococcal cassette chromosome-mec element typing, and presence of the Panton-Valentine leukocidin gene were evaluated in a collection of 15 clinical isolates. Clusters obtained with microarrays showed a high degree of similarity with those obtained by pulsed-field gel electrophoresis or variable number of tandem repeats. Clusters clearly segregated hospital-onset strains from community-onset strains. Moreover, the microarray approach allowed definition of novel marker genes and chromosomal regions specific for given groups of isolates, thus providing better discrimination and additional information compared to pulsed-field gel electrophoresis and variable number of tandem repeats. Finally, the comparative genome hybridization approach unraveled the occurrence of multiple horizontal transfer events leading to community-onset MRSA as well as the need for a specific genetic background in recipient strains for both the acquisition and the stability of the mec element.

Dynamics of bacterial hand contamination during routine neonatal care.

OBJECTIVE: To evaluate the dynamics of bacterial contamination of healthcare workers' (HCWs) hands during neonatal care. SETTING: The 20-bed neonatal unit of a large acute care teaching hospital in Geneva, Switzerland. METHODS: Structured observation sessions were conducted. A sequence of care began when the HCW performed hand hygiene and ended when the activity changed or hand hygiene was performed again. Alcohol-based handrub was the standard procedure for hand hygiene. An imprint of the five fingertips of the dominant hand was obtained before and after hand hygiene and at the end of a sequence of care. Regression methods were used to model the final bacterial count according to the type and duration of care and the use of gloves. RESULTS: One hundred forty-nine sequences of care were observed. Commensal skin flora comprised 72.4% of all culture-positive specimens (n = 360). Other microorganisms identified were Enterobacteriaceae (n = 55, 13.8%); Staphylococcus aureus (n = 10, 2.5%); and fungi (n = 7, 1.8%). Skin contact, respiratory care, and diaper change were independently associated with an increased bacterial count; the use of gloves did not fully protect HCWs' hands from bacterial contamination. CONCLUSIONS: These data confirm that hands become progressively contaminated with commensal flora and potential pathogens during neonatal care, and identify activities at higher risk for hand contamination. They also reinforce the need for hand hygiene after a sequence of care, before starting a different task, and after glove removal.

Comparison of waterless hand antisepsis agents at short application times: raising the flag of concern.

OBJECTIVE: Although alcohol-based hand rinses and gels have recommended application times of 30 to 60 seconds, healthcare workers usually take much less time for hand hygiene. We compared the efficacies of four alcohol-based hand rubs produced in Europe (hand rinses A, B, and C and one gel formulation) with the efficacy of the European Norm 1500 (EN 1500) reference waterless hand antisepsis agent (60% 2-propanol) at short application times. DESIGN: Comparative crossover study. SETTING: Infection Control Program laboratory of a large tertiary-care teaching hospital. PARTICIPANTS: Twelve healthy volunteers. INTERVENTION: Measurement of residual bacterial counts and log reduction factors following inoculation of fingertips with Staphylococcus aurens American Type Culture Collection (ATCC) 6538, Pseudomonas aeruginosa ATCC 15442, and a clinical isolate of Enterococcus faecalis. RESULTS: All hand rinses satisfied EN 1500 standards following a single application for 15 and 30 seconds, but reduction factors for the gel formulation were significantly lower for all tested organisms (all P < .025). CONCLUSIONS: Under stringent conditions similar to clinical practice, all three hand rinses proved to be more efficacious than the marketed alcohol-based gel in reducing bacterial counts on hands. Further studies are necessary to determine the in vivo efficacy of alcohol-based gels and whether they are as efficacious as alcohol-based rinses in reducing the transmission of nosocomial infections.

Legionnaires' disease in a renal transplant recipient: nosocomial or home-grown?

Legionnaires' disease is a community-acquired or hospital-acquired pneumonia, and the immunocompromised patient is at particular risk. We report a case of serogroup 1 pneumonia in a renal transplant patient shortly after grafting. No source of infection was identified in the hospital unit, but an extended investigation located patient exposure to a shower during a weekend home stay. Sampling at the hospital, in the patient's flat, other flats, and the laundry of the same building returned only one positive result from the patient's showerhead. Strain identity was confirmed by pulsed-field electrophoresis and amplified fragment length polymorphism. Guidelines recommend -free water for transplant units, but further epidemiologic evidence is required before extending this preventive approach to the patient's home.