Major Article
A 10-year prospective surveillance of nosocomial infections in neonatal intensive care units

https://doi.org/10.1016/j.ajic.2006.06.013Get rights and content

Background

We report on nosocomial infections (NIs), causative organisms, and antimicrobial susceptibility patterns in neonates who were admitted to neonatal intensive care units (NICUs), and assess the performance of birth weight (BW) as a variable for risk-stratified NI rate reporting.

Methods

A prospective, 10-year follow-up, open cohort study that involved six Brazilian NICUs was conducted. The NI incidence rates were calculated using different denominators.

Results

Six thousand two hundred forty-three newborns and 450 NICU-months of data were available for analysis. This included 3603 NIs that occurred in 2286 newborns over 121,008 patient-days. The most frequent NIs were primary bloodstream infection (pBSI; 45.9%), conjunctivitis (12.1%), skin infections (9.6%), and pneumonia (6.8%). Only the pBSI (but not pneumonia or central venous catheter–related pBSI) rate distribution differed significantly with varying BW. Gram-negative rods (mainly Klebsiella sp. and Escherichia coli) were responsible for 51.6% episodes of pBSI. Gram-positive organisms (mainly coagulase-positive staphylococci) accounted for 37.4%. Candida sp. was the fourth isolated organism. A high resistance to third-generation cephalosporins was recorded in K pneumoniae and E coli isolates.

Conclusions

This report highlights the burden of NI, and identifies the major focus for future NI control and prevention programs. Except for pBSI, BW had a poor performance as a variable for risk-stratified NI rate reporting.

Introduction

Newborns who are admitted to intensive care units (ICUs) are at a high risk for developing nosocomial infections (NIs), because of the severity of their illness and exposure to invasive medical devices (e.g., mechanical ventilator [MV], central venous catheter [CVC]) and resistant microorganisms.1, 2, 3, 4, 5 Despite the recent advances in intensive medical care—although life-saving—they expose critically ill patients to several infectious and noninfectious complications. The NIs among neonates result in substantial increases in morbidity, mortality, length of hospital stay, and costs.5, 6, 7

Birth weight (BW) has been advocated by the Centers for Disease Control and Prevention (CDC) as a variable for device-associated NI risk-stratified rate reporting in high-risk nurseries;8 however, this strategy has been evaluated rarely in neonates who are admitted to neonatal ICUs (NICUs) in developing countries. Furthermore, little interest has been shown in the literature in using this strategy for nondevice-associated NIs in developed and developing countries. The objectives of this study were two-fold: to report on NIs, causative organisms, and antimicrobial susceptibility patterns in a large cohort of neonates who were cared for during a 10-year period in six NICUs in Belo Horizonte, Brazil and to assess whether BW is a useful variable for major site-specific NI rate reporting in this cohort.

Section snippets

Patients and setting

From January 1993 to December 2002, all consecutive infants aged < 28 days who were admitted to a participating NICU were enrolled in a prospective, multicentric, open cohort study. This study involved six geographically close NICUs in Belo Horizonte, Brazil and its metropolitan area. Participating institutions are 8- to 24-bed, medium- to high-complexity, medical-surgical, nonuniversity NICUs. These NICUs provide care to critically ill newborns, extremely low BW premature infants, neonates for

Results

From January 1993 to December 2002, 6243 neonates were admitted to the NICUs, and a total of 450 NICU-months of data was available for analysis. This included 3603 NIs that occurred in 2286 newborns over 121,008 patient-days. Means for the overall NI patient and patient-day rates were 57.7 infections per 100 patients and 29.8 infections per 1000 patient-days, respectively. A single episode of infection was diagnosed in 1584 (69.3%) patients, and two or more infections were diagnosed in 702

Discussion

Nosocomial infection causative organisms, and antimicrobial susceptibility profiles are reported in a cohort of 6243 neonates who were admitted to an NICU during a 10-year period, and the performance of BW stratification for NI rate reporting is assessed. Frequency distribution of NI in this cohort was similar to that in National Nosocomial Infections Surveillance (NNIS) system's NICUs.14 As in most previous reports,2, 4, 7, 14 pBSI was the main cause of NI. The pBSI occurred at a rate of 26.5

Summary

This report clearly highlights the burden of NI in this subset of critically ill infants. The incidence of NI was high in our setting as compared with external benchmarks; further efforts are needed to better understand the causes and to control the spread of these infections. Except for pBSI, BW had a poor performance as a variable for risk-stratified NI rate reporting in our setting.

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