Pseudomonas aeruginosa outbreaks in the neonatal intensive care unit – a systematic review of risk factors and environmental sources

Abstract

Pseudomonas aeruginosa is a Gram-negative bacterium commonly occurring in soil and water. It is an opportunistic pathogen and an important cause of healthcare-associated infections, particularly among infants in neonatal intensive care units (NICUs). Several reports regarding outbreaks of P. aeruginosa in NICUs have been published. MEDLINE and EMBASE databases were searched using the MeSH terms [Pseudomonas aeruginosa], [Outbreak OR Infection OR bacteraemia, OR sepsis OR disease] and [Neonat* OR baby OR babies OR newborn*]. Fifteen studies describing a total of 414 infants colonized or infected with P. aeruginosa were reviewed. The mean percentage of infections occurring in the populations that had been colonized by the organism (calculated as n infected /n infected +n colonized ) was 22 %. Environmental sampling was performed in 14 studies, nine of which detected P. aeruginosa. The risk factors identified were antimicrobial drug use and the number of days of antimicrobial therapy prescribed before positive blood culture, exposure to particular healthcare workers (HCW), transfusion of blood products, and intravenous delivery of nutrients/electrolytes. Exposure to umbilical venous catheters was associated with bloodstream infections. Increasing age and use of artificial fingernails were risk factors for colonization of hands of HCWs. Low birth weight pre-term infants were at greater risk of mortality from P. aeruginosa infection than older infants. BackgroundPseudomonas aeruginosa is a Gram-negative bacterium commonly occurring in soil and water. It is an opportunistic pathogen, causing disease in vulnerable individuals, such as the immunocompromised, those where host defences have been breached, such as burns patients, and infants in whom the immune system is not yet developed. Most commonly, P. aeruginosa infections occur in the urinary tract, in burn wounds and as chronic lung infections in cystic-fibrosis patients. However, the organism is also an important cause of healthcare-associated infections, particularly among infants in neonatal intensive care units (NICUs) (Jarvis et al., 1987) owing to their underdeveloped immune system and the fact that such infants are often intubated, catheterized with intravascular catheters/devices in-situ, and/or receiving parenteral nutrition, which may increase risk of infection (Gaynes et al., 2005). Unfortunately, such infections in neonates can be fatal, as was the case in a recent UK outbreak in which four babies died (Wise, 2012). The ubiquitous nature of P. aeruginosa in the environment makes the sources of such outbreaks difficult to identify.Several outbreaks of P. aeruginosa colonization and infection in NICUs have been published. Simon et al. (2008) published a systematic review of confirmed outbreaks in both neonatal and paediatric patients that were identified using the PubMed database and the web-based register for nosocomial outbreaks. That review did not search for reports of outbreaks listed in the Embase database and so may have been biased by the omission ...

Post-Outbreak Investigation of Pseudomonas aeruginosa Faucet Contamination by Quantitative Polymerase Chain Reaction and Environmental Factors Affecting Positivity

“…2015;36 (11): [1337][1338][1339][1340][1341][1342][1343] Pseudomonas aeruginosa is a source of infection outbreaks, especially in intensive care units (ICUs). 1 Several of these outbreaks have been directly or indirectly linked to water distribution systems. [2][3][4][5][6][7][8][9][10][11][12][13][14] In ICUs, 30%-50% of P. aeruginosa infections have been associated with water.…”

Outbreak of Pseudomonas aeruginosa in a Neonatal Intensive Care Unit: Are Point-of-Use Filters Useful?

“…(4,(11)(12)(13)(14)(15)(16) P. aeruginosa is a ubiquitous bacterium in the environment, as well as part of endogenous flora, and therefore it is difficult to find the source of healthcare associated infections. (2,4,12) In the NICU of the CHC Zagreb, P. aeruginosa isolates have been found periodically in the past in surveillance cultures of neonates, but in March 2008 an increase in the total number of pseudomonas infections occurred, in comparison to the previous months.…”

“…(2,11) However, in some other studies, the environment as an exogenous source of pseudomonas infection (tap water, sinks, faucets, showers and hands of healthcare workers), has been confirmed. (1,2,5,10,12,13) Given that environmental sources, as well as the hands of healthcare workers, can play an important role in the colonization/ infection of patients, environmental samples (tap water, sinks, faucets, showers) were taken. (13,14) Pseudomonas isolates, except in surveillance cultures, were found in tap water, but not on the hands of healthcare workers.…”

Pathogen-Specific Clustering of Nosocomial Blood Stream Infections in Very Preterm Infants

“…In addition to transmission via the hands of staff, 24,[26][27][28][29] pathogens may also spread from inanimate point sources. An increased role for environmental sources has indeed been documented for S marcescens and P aeruginosa, as compared with other pathogens.…”

“…Reported ratios of sterile site infections to colonizations are 1:6 for S marcescens, as opposed to 1:27 for Klebsiella pneumonia. 23 Calculated attack rates, as defined as the ratio of infants with invasive infections and all infants positive for a certain pathogen, have been reported to be over 20% for P aeruginosa 24 and may exceed 50% for S marcescens during outbreaks. 7 S marcescens and P aeruginosa have also been found to figure prominently in NICUacquired bacterial conjunctivitis, 25 emphasizing their potential for patient-to-patient spreading in this environment.…”