Hospitalized premature infants are particularly vulnerable to morbidity and mortality from pertussis. Effective prevention and investigative and control measures are not well described.

To identify the source of nosocomial pertussis in a 2-month-old premature infant in a neonatal intermediate care nursery (ICN) and to critically review the investigation and outbreak control measures.

An ICN and a neonatal intensive care unit.

We queried healthcare workers (HCWs) and family members about cough illness and contacted potentially exposed patients to determine whether they had symptoms of pertussis. Culture and polymerase chain reaction (PCR) testing for Bordetella pertussis were performed by the hospital laboratory with specimens collected from symptomatic patients and HCWs. Levels of pertussis toxin immunoglobulin G antibodies were measured in HCWs with cough of at least 14 days' duration at a public health laboratory. Extensive control measures were instituted.

Four ICN HCWs met the clinical case definition for presence of pertussis. Serologic test results were positive for 3 of the HCWs. The primary case patient was a 36-year-old HCW with a cough illness of 3-weeks' duration that was accompanied by paroxysms, whoop, posttussive emesis, and pneumothorax. Among the 4 affected HCWs, the duration of cough illness prior to identification of the infant index patient ranged from 11 to 25 days. Outbreak control measures included isolation of the infant case patient, furlough and treatment of symptomatic HCWs, administration of chemoprophylaxis to contacts, and surveillance for additional cases. Seventy-two infant patients and 72 HCWs were exposed and were given antibiotic prophylaxis. One additional case of pertussis, confirmed by PCR and culture, occurred in a resident physician who declined prophylaxis; she had cared for the index patient but had no contact with symptomatic HCWs.

HCWs or patients may serve as the source of pertussis in nosocomial outbreaks, which can result in substantial morbidity and outlay of resources for control measures. Our review suggested that a diagnosis of pertussis should be an early consideration for HCWs with cough illness. Targeted pertussis immunization of HCWs, employee health policies that provide for testing and furlough of HCWs with prolonged cough, and monitoring of HCWs for compliance with infection control measures could reduce the morbidity and costs associated with pertussis outbreaks. These measures will require evaluation of their effectiveness.

In September 1999, a pertussis outbreak was detected among surgical staff of a 138-bed community hospital. Patients were exposed to Bordetella pertussis during the 3-month outbreak period.

To describe the outbreak among surgical staff, to evaluate implemented control measures, and to determine whether nosocomial transmission occurred.

Clinical pertussis was defined as acute cough illness with a duration of 14 days or more without another apparent cause; persons with positive culture, PCR, or serologic test results were defined as having laboratory-confirmed pertussis. Surgical healthcare workers (HCWs) were interviewed regarding pertussis symptoms, and specimens were obtained for laboratory analysis. Patients exposed to B. pertussis during an ill staff member's 3-week infectious period were interviewed by phone to determine the extent of nosocomial spread.

A total of 53 HCWs assigned to the surgical unit and 146 exposed patients. HCWs with pertussis were defined as case subjects; HCWs without pertussis were defined as non-case subjects.

Twelve (23%) of 53 HCWs had clinical pertussis; 6 cases were laboratory confirmed. The median cough duration in the 12 case subjects was 27 days (range, 20-120 days); 10 (83%) had paroxysms. Eleven (92%) of 12 case subjects and 28 (86%) of 41 non-case subjects received antibiotic treatment or prophylaxis. Seven case subjects (58%) reported they always wore a mask when near patients. Of 146 patients potentially exposed to pertussis from the 12 case subjects, 120 (82%) were interviewed; none reported a pertussis-like illness.

Surgical staff transmitted B. pertussis among themselves; self-reported data suggests that these HCWs did not transmit B. pertussis to their patients, likely because of mask use, cough etiquette, and limited face-to-face contact. Control measures might have helped limit the outbreak once pertussis was recognized.

The primary objective was to determine the rate of and risk factors for nosocomial primary bloodstream infection (BSI) in pediatric intensive care unit (PICU) patients in order to determine the validity of our previously published findings. The secondary objective was to analyze whether risk factors for primary BSI differed by organism type, particularly whether device use was more strongly associated with BSI due to gram-positive organisms.

Prospective cohort study.

St. Louis Children's Hospital, a 235-bed academic tertiary care center with a 28-bed combined medical and surgical PICU.

PICU patients admitted between September 1, 1999, and September 1, 2001.

Nosocomial primary BSIs.

Of 2,310 patients, 55% were male, and 73% were white. There were 124 episodes of primary BSI in 87 patients (3.8%). Coagulase-negative Staphylococcus organisms were the leading cause of BSI (42 of 124 episodes). The rate of BSI was 9 BSIs/1,000 central venous catheter–days. Multiple logistic regression analysis showed that independent predictors of nosocomial primary BSI included higher number of arterial catheter–days (adjusted odds ratio [aOR], 5.7 per day of arterial catheterization; 95% confidence interval [CI], 3.4-9.8), higher number of packed red blood cell transfusions (aOR, 1.2; 95% CI, 1.1-1.4), and genetic syndrome (aOR, 4.7; 95% CI, 1.8-12). Severity of illness, underlying illnesses, and medications were not independently associated with increased risk of nosocomial BSI.

Arterial catheter use and packed red blood cell transfusion are potentially modifiable risk factors for nosocomial primary BSI in PICU patients. Genetic syndromes may be markers for unrecognized immune defects that impair host defense against microorganisms.

To compare the cumulative incidence of infections acquired in the pediatric intensive care unit (PICU) and neonatal intensive care unit (NICU).

Estimation of the cumulative incidence of infections with data obtained from the Pediatric Prevention Network (PPN) point-prevalence survey and observed rates from the National Nosocomial Infections Surveillance (NNIS) system.

Ten hospitals participated in both the PPN survey and NNIS system.

All patients present on the PPN survey dates (August 4, 1999, or February 1, 2000) in the NICUs or PICUs of the PPN hospitals were included in the survey. Point prevalences for PICU-acquired and for NICU-acquired infections at these hospitals were calculated from the survey data. The cumulative incidence rates were estimated from the point prevalence rates using a standard formula and a standard method for calculating the time to recovery (ie, on the basis of the assumption that discontinuance of antimicrobial therapy indicates recovery from infection); alternate methods to judge the time to recovery from infection were also explored.

The average cumulative incidence of intensive care unit-acquired infection for NICUs and PICUs combined (all units), as measured by NNIS, was 14.1 cases per 100 patients; in comparison, the prevalence was 14.06 cases for 100 patients (median difference, —0.95 cases per 100 patients; 95% confidence interval, —4.6 to 5.0 cases per 100 patients), and the estimated cumulative incidence using the standard method of calculating the time to recovery was 13.8 cases per 100 patients (median difference, —1.5 cases per 100 patients; 95% confidence interval, —9.1 to 2.9 cases per 100 patients). Estimates of cumulative incidence using alternate methods for calculation of time to recovery did not perform as well (range, 4.9-100.9 cases per 100 patients). The average incidence density for all units, as measured by the NNIS system, was 6.8 cases per 1,000 patient-days, and the estimate of incidence density using the standard method of calculating the time to recovery was 3.6 cases per 1,000 patient-days (median difference, 4.3 cases per 1,000 patient-days; 95% confidence interval, 0.9 to 9.2 cases per 1,000 patient-days). Estimated incidence densities using alternate methods for determining recovery time correlated closely with observed incidence densities.

In this patient population, the simple point prevalence provided the best estimate of cumulative incidence, followed by use of a standard formula and a standard method of calculating the time to recovery. Estimation of incidence density using alternate methods performed well. The standard formula and method may provide an even better estimate of cumulative incidence than does simple prevalence in general populations.

To determine risk factors for nosocomial infection in a neonatal intensive care unit (NICU).

A prospective, open cohort study.

A 22-bed NICU.

Neonates admitted to a single NICU during 1994-1998 were included in the study. Outcome variables included central venous catheter (CVC)–associated primary bloodstream infection (BSI), non–CVC-associated primary BSI, pneumonia, and overall nosocomial infection. Independent variables included birth weight, use of mechanical ventilation (MV), duration of MV, use of a CVC, duration of CVC use, duration of NICU stay, gestational age, congenital malformation, maximum (ie, worst) base excess, and maximum and minimum fraction of inspired oxygen (FIO2) for maintaining appropriate blood saturation levels during the first 12 hours after NICU admission.

A total of 1051 neonates were admitted to the NICU. Overall, 358 NIs were diagnosed. Non–CVC-associated primary BSI was the most frequent nosocomial infection (in 195 neonates [54.5%]), followed by pneumonia (46 [12.8%]), and CVC-associated primary BSI (35 [9.8%]). The mortality rate was 16%. In the final logistic regression model, the following 5 risk factors were found to be predictive of nosocomial infection development: use of MV, longer duration of MV, longer duration of CVC use, longer duration of NICU stay, and low maximum appropriate FIO2.

Invasive device use and duration of use continue to greatly influence the development of nosocomial infection in NICUs. In our cohort, birth weight showed no influence on the development of nosocomial infection. Low maximum FIO2 influenced the occurrence of overall nosocomial infection.

To identify the main risk factors for the acquisition of candidemia in children with congenital heart disease (CHD) in order to improve the clinical management of these patients.

A case-control study.

A large tertiary-care referral center in Spain with a pediatric intensive care unit (PICU) to which more than 500 children with CHD are admitted annually.

All patients had CHD and were admitted to the PICU during 1995-2000. Case patients were defined as patients with candidemia, and control patients were defined as patients without candidemia.

Twenty-eight case patients and 47 control subjects were included in the study. Case patients were younger (mean age [ ± SD], 12.5 ± 32.0 vs 38.0 ± 48.0 months; P< .01) and had a longer median PICU stay (19 vs 4 days; P < .01), and a greater percentage of case patients previously had Candida species isolated from specimens other than blood (eg, bronchial aspirates, urine, or skin specimens) (39% vs 4%; P<.01). Severity of clinical condition, as measured by the Therapeutic Intervention Scoring System (TISS) 1 week after PICU admission (odds ratio, 1.15; 95% confidence interval, 1.05-1.26; P<.01), and receipt of antibiotic treatment for more than 5 days (odds ratio, 13.42; 95% confidence interval, 1.31-137.13; P = .03) were independently associated with the development of candidemia.

Patients with CHD who have a high TISS score 1 week after PICU admission and patients who have received prolonged antibiotic therapy should be considered at high risk for candidemia. Our results suggest that shorter courses of antibiotic therapy, routine surveillance culture for Candida species, and initiation of preemptive or empirical antifungal treatment could help in the clinical management of these patients.

To describe the investigation and interventions necessary to contain an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection in a neonatal intensive care unit (NICU).

Retrospective case finding that involved prospective performance of surveillance cultures for detection of MRSA and molecular typing of MRSA by repetitive-sequence polymerase chain reaction (rep-PCR).

Level III NICU in a tertiary care center.

Three neonates in a NICU were identified with MRSA bloodstream infection on April 16, 2004. A point prevalence survey identified 6 additional colonized neonates (attack rate, 75% [9 of 12 neonates]). The outbreak strain was phenotypically unusual.

Cohorting and mupirocin therapy were initiated for neonates who had acquired MRSA during the outbreak. Contact precautions were introduced in the NICU, and healthcare workers (HCWs) were retrained in cleaning and disinfection procedures and hand hygiene. Noncolonized neonates and newly admitted patients had surveillance cultures performed 3 times per week.

Two new colonized neonates were identified 1 month later. HCW X, who had worked in the NICU since June 2003, was identified as having chronic otitis. MRSA was isolated from cultures of swab specimens from HCW X's ear canal and nares. HCW X was epidemiologically linked to the outbreak. Molecular typing (by rep-PCR) confirmed that the isolates from HCW X and from the neonates were more than 90% similar. Retrospective review of NICU isolates revealed that the outbreak strain was initially cultured from a neonate 2 months after HCW X began working on the unit. The epidemic strain was eradicated after removing HCW X from patient care in the NICU.

An outbreak of MRSA colonization and infection in a NICU was epidemiologically linked to a HCW with chronic otitis externa and nasal colonization with MRSA. Eradication was not achieved until removal of HCW X from the NICU. Routine surveillance for MRSA may have allowed earlier recognition of the outbreak and is now standard practice in our NICU.

To determine the source of an outbreak of Salmonella javiana infection.

Case-control study.

A total of 101 culture-confirmed cases and 540 epidemiologically linked cases were detected between May 26, 2003, and June 16, 2003, in hospital employees, patients, and visitors. Asymptomatic employees who had eaten in the hospital cafeteria between May 30 and June 4, 2003, and had had no gastroenteritis symptoms after May 1, 2003, were chosen as control subjects.

A 235-bed academic tertiary care children's hospital.

Isolates from 100 of 101 culture-confirmed cases had identical pulsed-field gel electrophoresis patterns. A foodhandler with symptoms of gastroenteritis was the presumed index subject. In multivariate analysis, case subjects were more likely than control subjects to have consumed items from the salad bar (adjusted odds ratio [aOR], 5.3; 95% confidence interval [CI], 2.3-12.1) and to have eaten in the cafeteria on May 28 (aOR, 9.4; 95% CI, 1.8-49.5), May 30 (aOR, 3.6; 95% CI, 1.0-12.7), and/or June 3 (aOR, 4.0; 95% CI, 1.4-11.3).

Foodhandlers who worked while they had symptoms of gastroenteritis likely contributed to the propagation of the outbreak. This large outbreak was rapidly controlled through the use of an incident command center.

To investigate the characteristics and origins of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from neonatal patients admitted to a tertiary care hospital from local and primary care obstetrics clinics.

Molecular typing study.

A 1,278-bed tertiary care hospital (Samsung Medical Center) and 2 primary obstetrics clinics in Seoul, Korea.

The genotypic characteristics of 12 MRSA samples isolated from 11 neonatal patients transferred from 2 primary care obstetrics clinics to a tertiary care hospital were investigated by means of multilocus sequence typing, spa (staphylococcal protein A) typing, and SCCmec typing. Ten MRSA strains isolated from workers and environments in the associated obstetrics clinics were also investigated.

Although the antibiograms of isolates from 2 obstetrics clinics differed, no strain showed multidrug resistance to antimicrobials. Multilocus sequence typing analysis showed that all 22 MRSA isolates analyzed in this study had sequence type 1 (with the allelic profile 1-1-1-1-1-1-1), sequence type 493 (62-1-1-1-1-1-1), or a novel sequence type (25-1-1-1-1-1-1) and that all belonged to a single clonal complex (clonal complex 1). Moreover, they all contained SCCmec type IVA and the identical spa type (UJEBKBP). These genotypic characteristics are similar to those of typical community-associated MRSA strains rather than the hospital-acquired MRSA strains common in Korea.

The findings of this study suggest that community-acquired MRSA strains can spread in primary care clinics and be imported into tertiary care settings.

Newborns in a hospital nursery were exposed to a mother whose sputum was direct-smear negative for acid-fast bacilli but culture positive for Mycobacterium tuberculosis. Given the low risk for exposure, the high susceptibility of infants to M. tuberculosis infection, and the possibility of hepatotoxicity due to isoniazid therapy, a decision analysis model was used to determine whether administration of isoniazid prophylaxis against tuberculosis is preferable to no administration of prophylaxis.

A decision analysis tree was constructed with software, using probabilities from the literature and costs from local health facilities. The expected values for each strategy were obtained, and sensitivity analyses were performed.

For the strategy in which prophylaxis was administered under direct observation (DO), the probability for survival was 0.999980. For the strategy in which no prophylaxis was administered, the probability of survival was 0.999950, which corresponds to 3 more deaths per 100,000 patients than with the DO prophylaxis strategy. The incremental cost-effectiveness of the DO prophylaxis strategy was $21,710,000 per death prevented. Sensitivity analysis for survival showed that the DO prophylaxis strategy was preferable to the strategy in which no prophylaxis is given if the probability of infection was >0.0002, the probability of tuberculous disease in an infected infant who did not receive prophylaxis was greater than 0.12, the probability of dying from tuberculosis was greater than 0.025, the probability of hepatotoxicity was less than 0.004, and the probability of dying from hepatotoxicity was less than 0.04. For the strategy in which prophylaxis was administered under non-DO conditions (ie, by parents), the incremental cost-effectiveness was $929,500 per death prevented, which is approximately 5% of the incremental cost-effectiveness of the DO prophylaxis strategy.

This model provides a structure for determining the preferable prophylaxis strategies for different risks of exposure to tuberculosis in a nursery. Administration of prophylaxis is preferable to no administration of prophylaxis, unless the probability of infection is extremely low.

To identify the factors that inhibit or motivate influenza vaccination among healthcare workers (HCWs).

In March 2000, we prepared 34-item questionnaire for both vaccine recipients and nonrecipients regarding demographic characteristics, factors motivating and inhibiting vaccination, and knowledge and attitudes about influenza vaccination. On the basis of the results of our survey, an aggressive hospital vaccination campaign was undertaken. In April 2004, after the 4-year campaign, the same questionnaire was again administered to HCWs.

In both 2000 and 2004, the main motives for undergoing influenza vaccination were “hospital campaign” and “recommendation by colleagues”; the percentage of respondents who were motivated by the hospital campaign had remarkably increased from 27% in 2000 to 52% in 2004 (P<.001), whereas the percentage who were motivated by recommendation by colleagues had not changed significantly (21% vs 14%). Qverall, the 4 reasons most frequently cited by HCWs for noncompliance with vaccination were insufficient available time, confidence in their health, doubt about vaccine efficacy, and fear of injection. In 2000, vaccination rates were below 30%, irrespective of occupation. After an aggressive vaccination campaign, the increase in the vaccination rate was highest among the nursing staff, increasing from 21% in 2000 to 92% in 2004, whereas the vaccination rate among the physicians was still below 60%.

We conclude that a hospital campaign can markedly improve influenza vaccination rates among HCWs. Both a mobile cart system and free vaccine supply contributed to improving the vaccination rates in our study. In addition, a specifically tailored intervention strategy was required.

Recognizing that the potential transmission of influenza virus would be concentrated at a hospital's primary point of entry, we determined rates of staff compliance with the influenza vaccination recommendations of the Advisory Committee on Immunization Practices (ACIP) in the Emergency Department (ED). We describe the basic knowledge concerning influenza transmission and factors influencing vaccination decisions among ED staff.

Cross-sectional study.

A large urban teaching hospital. Participants included ED staff, visiting professionals from other departments, and emergency medical service personnel transferring patients to the hospital.

Of 230 surveys that were distributed, 200 were completed. One hundred one respondents (51%) were female. The overall influenza vaccination rate was 50%. Having had influenza previously was the most instrumental factor in whether or not a respondent chose vaccination (P<.001). Use of the Employees Health Services Free Vaccine Program (FVP) was a very important factor influencing whether ED staff sought influenza vaccination (P<.0001). Prior knowledge of the ACIP recommendations proved to be not statistically important (P = .03). A significant factor for respondents declining vaccination was the concern that illness could be caused by the vaccine (P<.0001). Variables such as sex of the respondents (P = .6714) and type of job (P = .3628) were not associated with vaccination.

Despite ACIP recommendations, 50% of respondents did not receive an influenza vaccination. Misconceptions regarding influenza vaccine efficacy, concerns about adverse effects, and fear of contracting illness were significantly associated with noncompliance with vaccination. Variables that were important contributors to compliance with vaccination were prior influenza illness and services rendered by the FVP.