Phase II studies of nebulised Arikace in CF patients with Pseudomonas aeruginosa infection.

RATIONALE: Arikace is a liposomal amikacin preparation for aerosol delivery with potent Pseudomonas aeruginosa killing and prolonged lung deposition. OBJECTIVES: To examine the safety and efficacy of 28 days of once-daily Arikace in cystic fibrosis (CF) patients chronically infected with P aeruginosa. METHODS: 105 subjects were evaluated in double-blind, placebo-controlled studies. Subjects were randomised to once-daily Arikace (70, 140, 280 and 560 mg; n=7, 5, 21 and 36 subjects) or placebo (n=36) for 28 days. Primary outcomes included safety and tolerability. Secondary outcomes included lung function (forced expiratory volume at one second (FEV1)), P aeruginosa density in sputum, and the Cystic Fibrosis Quality of Life Questionnaire-Revised (CFQ-R). RESULTS: The adverse event profile was similar among Arikace and placebo subjects. The relative change in FEV1 was higher in the 560 mg dose group at day 28 (p=0.033) and at day 56 (28 days post-treatment, 0.093L±0.203 vs -0.032L±0.119; p=0.003) versus placebo. Sputum P aeruginosa density decreased >1 log in the 560 mg group versus placebo (days 14, 28 and 35; p=0.021). The Respiratory Domain of the CFQ-R increased by the Minimal Clinically Important Difference (MCID) in 67% of Arikace subjects (560 mg) versus 36% of placebo (p=0.006), and correlated with FEV1 improvements at days 14, 28 and 42 (p<0.05). An open-label extension (560 mg Arikace) for 28 days followed by 56 days off over six cycles confirmed durable improvements in lung function and sputum P aeruginosa density (n=49). CONCLUSIONS: Once-daily Arikace demonstrated acute tolerability, safety, biologic activity and efficacy in patients with CF with P aeruginosa infection.

Varicella in the neonatal ICU due to the Varicella vaccine Oka strain.

BACKGROUND: Varicella vaccination of non-immune post-partum women is recommended to reduce the risk of chickenpox in mothers and their infants. Though rare, transmission of the varicella vaccine strain vOka can occur from recent vaccinees to non-immune contacts who usually develop mild chickenpox. METHODS/RESULTS: Here we describe an infant hospitalized in the neonatal ICU with vaccine-strain varicella due to transmission from their mother who received the varicella vaccine post-partum. We describe the infection prevention and control strategies implemented to prevent further transmission. CONCLUSION: Vaccine-strain varicella transmission from mother to infant is a rare event and its occurrence in the neonatal ICU setting can be challenging. Anticipatory guidance for mothers vaccinated in the postpartum period and support of parents of an infected infant are recommended.

Use of antibiotics in paediatric long-term care facilities.

BACKGROUND: Adult long-term care (LTC) facilities have high rates of antibiotic use, raising concerns about antimicrobial resistance. Few studies have examined antibiotic use in paediatric LTC facilities. AIM: To describe antibiotic use in three paediatric LTC facilities and to describe the factors associated with use. METHODS: A retrospective cohort study was conducted from September 2012 to December 2015 in three paediatric LTC facilities. Medical records were reviewed for demographics, healthcare-associated infections (HAIs), antimicrobial use and diagnostic testing. Logistic regression was used to identify predictors for antibiotic use. The association between susceptibility testing results and appropriate antibiotic coverage was determined using Chi-squared test. FINDINGS: Fifty-eight percent (413/717) of residents had at least one HAI, and 79% (325/413) of these residents were treated with at least one antibiotic course, totalling 2.75 antibiotic courses per 1000 resident-days. Length of enrolment greater than one year, having a neurological disorder, having a tracheostomy, and being hospitalized at least once during the study period were significantly associated with receiving antibiotics when controlling for facility (all P < 0.001). Diagnostic testing was performed for 40% of antibiotic-treated HAIs. Eighty-six percent of antibiotic courses for identified bacterial pathogens (201/233) provided appropriate coverage. Access to susceptibility testing was not associated with appropriate antibiotic choice (P = 0.26). CONCLUSION: Use of antibiotics in paediatric LTC facilities is widespread. There is further need to assess antibiotic use in paediatric LTC facilities. Evaluation of the adverse outcomes associated with inappropriate antibiotic use, including the prevalence of resistant organisms in paediatric LTC facilities, is critical.

Pseudomonas aeruginosa pili bind to asialoGM1 which is increased on the surface of cystic fibrosis epithelial cells.

The basis for the unique association of Pseudomonas aeruginosa and the cystic fibrosis (CF) lung has remained obscure despite major advances in the understanding of the molecular genetic cause of this disease. There is evidence to suggest that abnormalities in CF transmembrane conductance regulator function result in alterations in the glycosylation of epithelial components. The number of asialoGM1 residues, as representative of a class of glycolipids which contain a GalNAc beta 1-4Gal sequence for P. aeruginosa attachment, was quantified by flow cytometric studies of respiratory epithelial cells in primary culture from both CF patients and normal subjects. Superficial asialoGM1 was detected on 12% of the CF cells as compared with 2.9% of the cells from normal control subjects (P = 0.03, chi 2 = 4.73), and more asialoGM1 residues were exposed on CF cells after modification by P. aeruginosa exoproducts. AsialoGM1, but not the sialylated glycolipid GM1, was demonstrated to be a receptor for 125I-labeled P. aeruginosa pilin, a major adhesin for this organism, and exogenous asialoGM1 was found to competitively inhibit P. aeruginosa adherence to epithelial cells, thus, confirming the biological role of the asialoGM1 receptor. Quantitative and qualitative differences in the sialylation of superficial glycolipids in CF epithelial cells may directly contribute to the colonization of the CF lung by P. aeruginosa.

Production of the Pseudomonas aeruginosa neuraminidase is increased under hyperosmolar conditions and is regulated by genes involved in alginate expression.

The pathogenesis of Pseudomonas aeruginosa infection in cystic fibrosis (CF) is a complex process attributed to specific characteristics of both the host and the infecting organism. In this study, the properties of the PAO1 neuraminidase were examined to determine its potential role in facilitating Pseudomonas colonization of the respiratory epithelium. The PAO1 neuraminidase was 1000-fold more active than the Clostridium perfringens enzyme in releasing sialic acid from respiratory epithelial cells. This effect correlated with increased adherence of PAO1 to epithelial cells after exposure to PAO1 neuraminidase and was consistent with in vitro studies demonstrating Pseudomonas adherence to asialoganglioside receptors. The regulation of the neuraminidase gene nanA was examined in Pseudomonas and as cloned and expressed in Escherichia coli. In hyperosmolar conditions neuraminidase expression was increased by 50% (P less than 0.0004), an effect which was OmpR dependent in E. coli. In Pseudomonas the osmotic regulation of neuraminidase production was dependent upon algR1 and algR2, genes involved in the transcriptional activation of algD, which is responsible for the mucoid phenotype of Pseudomonas and pathognomonic for chronic infection in CF. Under the hyperosmolar conditions postulated to exist in the CF lung, nanA is likely to be expressed to facilitate the initial adherence of Pseudomonas to the respiratory tract.

Surgical site infections in a longitudinal cohort of neonatal intensive care unit patients.

OBJECTIVE: To estimate the incidence and identify risk factors for surgical site infections (SSIs) among infants in the neonatal intensive care unit (NICU). STUDY DESIGN: A prospective cohort study of infants undergoing surgical procedures from May 2009 to April 2012 in three NICUs was performed. SSI was identified if documented by an attending neonatologist and treated with intravenous antibiotics. Independent risk factors were identified using logistic regression, adjusting for NICU. RESULT: A total of 902 infants underwent 1346 procedures and experienced 60 SSIs (incidence: 4.46/100 surgeries). Risk factors for SSIs included younger chronological age (odds ratio (OR) 1.03 per day decrease, 95% confidence interval (CI) 1.01, 1.04), lower gestational age (OR 1.09 per week decrease, CI 1.02, 1.18), male sex (OR 1.17, CI 1.04, 1.34) and use of central venous catheter (OR 4.40, CI 1.19, 9.62). Only 43% had surgical site cultures obtained and Staphylococcus aureus was most commonly isolated. CONCLUSION: SSIs complicated 4.46% of procedures performed in the NICU. Although few modifiable risk factors for SSIs were identified, future efforts should focus on evaluating the impact of current prevention strategies on the incidence of neonatal SSI.

Nosocomial transmission of Mycobacterium tuberculosis in a children's hospital.

An infant was admitted for evaluation of respiratory distress and tracheomalacia. After several weeks of hospitalization, both the infant and her mother were diagnosed with culture-positive pulmonary tuberculosis (TB). Sixteen pediatric patients and 293 health care workers were evaluated for exposure to Mycobacterium tuberculosis. Tuberculin skin test conversions occurred in 6.7% of patients and 1.9% of pediatric health care workers. While nosocomial transmission of TB is relatively rare in children's hospitals, this report highlights the differences between TB control efforts in pediatric vs. adult facilities, including the importance of screening the adult visitors of children admitted with suspected TB.

Surveillance of pharyngeal colonization: detection and control of serious bacterial illness in low birth weight infants.

Routine surveillance for bacterial colonization has been used for the past three decades as a tool for the prediction of nosocomial infection in low birth weight infants; however, its usefulness has never been proven. A prospective cohort study was conducted to examine the utility of surveillance for pharyngeal colonization in detection and control of serious bacterial illness in low birth weight infants. One hundred fifty-four infants who weighed less than 1750 g and who were admitted to the Neonatal Intensive Care Unit were enrolled and followed for a total of 5620 infant-days. Pharyngeal cultures were collected at the time of enrollment and then weekly. All infants had bacterial pharyngeal colonization by the third day of life. Coagulase-negative staphylococci were the most common organisms cultured from the pharynx, followed by viridans streptococci and Staphylococcus aureus. More than 90% of the pharyngeal cultures grew multiple isolates. Gram-positive organisms, particularly coagulase-negative staphylococci, were the most prevalent organism recovered from blood and cerebrospinal fluid cultures. Fifty-two episodes of bacteremia and 6 episodes of cerebrospinal fluid infection occurred in 42 infants. Among infants with viridans streptococci in pharyngeal cultures, the subsequent risk of serious bacterial illness was significantly reduced (odds ratio = 0.16). However, pharyngeal cultures were poor predictors of the causative organism in an episode of serious bacterial illness. Pharyngeal and blood/cerebrospinal fluid cultures were concordant in only 11% of invasive infections. We conclude that pharyngeal surveillance cultures provide little clinically meaningful information and have no apparent utility in the Neonatal Intensive Care Unit setting.

Plesiomonas shigelloides sepsis and splenic abscess in an adolescent with sickle-cell disease.

Plesiomonas shigelloides is a rare cause of self-limiting gastroenteritis. We report a case of extraintestinal P. shigelloides infection in an adolescent with sickle-cell disease who presented with bacteremia complicated by a splenic abscess. Despite the high mortality rate reported in extraintestinal P. shigelloides infection, the patient survived after drainage of the abscess and treatment with antibiotics.

Observational study of the use of infection control interventions for Mycobacterium tuberculosis in pediatric facilities.

INTRODUCTION: Hospital transmission of Mycobacterium tuberculosis (TB) is a problem in US facilities where adults are treated. However, specific guidelines for facilities in which pediatric patients are cared for have never been defined, nor has any study attempted to assess pediatric health care worker (HCW) compliance with TB infection control (IC) guidelines. METHODS: An observational study was performed in two pediatric inpatient hospitals from May, 1996, to December, 1997. A trained observer tallied persons (i.e. professional HCWs, ancillary HCWs and non-HCWs) entering and leaving occupied TB isolation rooms and recorded adherence with IC practices (e.g. proper use of respirators, prompt door closures, door signage). RESULTS: Thirty children with confirmed or suspected TB were admitted during the study period and observed for a total of 242 h during which 656 visits by professional (n = 391) and ancillary (n = 131) HCWs and by family members (n = 134) were recorded. During 30% of visits doors remained open an average of 10 min, and during 20% of visits no respiratory protection was worn. In all, visitors wore the correct respiratory protection appropriately only 55% of the time. HCWs were more likely to wear respiratory protection when caring for children with a positive acid-fast bacillus smear than family members, but professional staff were no more likely than ancillary staff to do so. CONCLUSIONS: This is the first study to quantify compliance with IC practices for TB in pediatric hospitals. The majority of visitors entering TB isolation rooms occupied by children with confirmed or suspected TB complied with IC guidelines, but discrepancies were seen. Rather than relying on TB IC guidelines designed for adult facilities, guidelines specific for pediatric facilities that consider the local epidemiology of TB should be developed.

Evaluation of household contacts of children with positive tuberculin skin tests.

BACKGROUND: Associate investigation, defined as screening the contacts of children with positive tuberculin skin tests (TST) and normal chest radiographs, has been recommended to improve case finding for active tuberculosis (TB). The success of this strategy has not been adequately studied in either adults or children. METHODS: A 2-year prospective study was conducted wherein 187 children and adolescents with infection caused by Mycobacterium tuberculosis (positive TST and normal chest radiograph) were referred to a TB Screening Clinic. An associate investigation was performed among their 659 household contacts who were interviewed to assess risk factors for TB and screened with TSTs and with chest radiographs when appropriate. RESULTS: No cases of active TB were detected, but 32% of household contacts had TSTs > or = 10 mm and were candidates for preventive therapy. Logistic regression analysis revealed that household contacts with Calmette-Guérin bacillus immunization and foreign birth were 2.26 and 3.92 times more likely (P < 0.001 and 0.002, respectively) to be tuberculin-positive. Univariate analysis of the 187 households revealed that the following risk factors present in a household member were associated with detecting a household contact with a positive TST: Calmette-Guérin bacillus immunization (P = 0.001), foreign birth (P = 0.017) and a history of having hosted foreign visitors (P = 0.032). CONCLUSION: In this Hispanic immigrant population, primarily from the Dominican Republic, screening household contacts of children with positive TSTs did not identify new cases of active TB. However, this strategy did identify household contacts who were eligible for preventive therapy.

Molecular epidemiology of staphylococcal scalded skin syndrome in premature infants.

BACKGROUND: Outbreaks of nosocomial staphylococcal scalded skin syndrome (SSSS) in infants have been well-described associated with the well baby nursery or delivery room. We describe two cases of SSSS in very low birth weight infants in a neonatal intensive care unit (NICU) and the success of infection control strategies used to prevent an outbreak. METHODS: Staphylococcal scalded skin syndrome was diagnosed in two infants in the NICU: Case I (a 47-day-old, formerly 530-g female); and Case II diagnosed 48 h later (a 41-day old, formerly 706-g female). Multiple infection control measures were implemented: (1) isolation and intravenous antibiotic treatment of cases; (2) placement of exposed infants into a cohort; (3) prophylactic mupirocin treatment of the anterior nares of all infants in the NICU and staff colonized with Staphylococcus aureus; and (4) personnel hand washing with hexachlorophene. Detection of exfoliative toxin A and studies to determine the genetic relatedness of S. aureus strains isolated from patients and staff were performed. RESULTS: In addition to the two SSSS cases, S. aureus was isolated from 2 of 12 (17%) exposed asymptomatic infants, 2 of 20 (10%) ancillary staff, 8 of 30 (27%) nurses and 6 of 24 (25%) physicians. Exfoliative toxin A-producing strains were isolated from both cases and one asymptomatic infant. No toxin was expressed by strains isolated from staff. Pulse field gel electrophoresis demonstrated genetically identical strains of S. aureus from the two SSSS cases and the asymptomatic infant, whereas three staff members harbored strains genetically related to the case strain. Unexpectedly two additional unique clusters of genetically related S. aureus strains were identified from the surveillance cultures. CONCLUSIONS: This report documents the rare occurrence of nosocomial SSSS attributed to transmission in the NICU among extremely low birth weight infants. Multiple infection control strategies were effective in limiting the outbreak. Molecular epidemiology investigation supported a unique S. aureus strain responsible for this event and the presence of bidirectional spread between staff and patients of non-toxin-producing strains.

Diagnosis of pediatric tuberculosis in the modern era.

BACKGROUND: Correctly diagnosing tuberculosis (TB) in children is critical to provide appropriate treatment and to detect undiagnosed source cases. However, diagnosing TB in children may be difficult. OBJECTIVE: We sought to determine whether Amplicor, a Food and Drug Administration-approved polymerase chain reaction (PCR) assay used to detect Mycobacterium tuberculosis in sputum and computerized tomography (CT) would facilitate the diagnosis of TB in children. We also examined the applicability of the Centers for Disease Control and Prevention clinical case definition for TB. SETTING: A university-affiliated pediatric hospital in New York City. SUBJECTS: From March, 1995, to November, 1997, 27 children < 15 years of age (mean age, 3.9 years) were evaluated for suspected TB. RESULTS: M. tuberculosis was cultured from 5 of 76 (6.6%) gastric aspirate specimens, and PCR detected M. tuberculosis DNA in 3 (4.1%) of these specimens. There was poor correlation between culture and PCR because 6 specimens were discordant. CT scans were diagnostic of mediastinal or hilar adenopathy in 6 children with equivocal or negative chest radiographs and confirmed adenopathy in 8 others. Six children received alternative diagnoses. CONCLUSIONS: We conclude that the commercially available PCR technology had very limited utility in detecting M. tuberculosis from gastric aspirates, but CT scans were useful in assessing pediatric patients with suspected TB.

Nonsusceptible Streptococcus pneumoniae in children with chronic otitis media with effusion and recurrent otitis media undergoing ventilating tube placement.

CONTEXT: Children with chronic otitis media are at risk for nonsusceptible Streptococcus pneumoniae (NSP) infection. If these children undergo ventilating tube placement, there is an opportunity to culture middle ear fluid and the nasopharynx to determine carriage of NSP. OBJECTIVE: To determine the incidence of NSP carriage, NSP antibiotic susceptibility and risk factors for NSP carriage in children with chronic otitis media undergoing tube placement. DESIGN AND SETTING: Prospective cohort study in an academic medical center with recruitment of patients from an otolaryngology private practice and clinic. PATIENTS: Children < 18 years of age undergoing tube placement for chronic otitis media. INTERVENTIONS: Myringotomy and tube placement, with culture of middle ear fluid and nasopharynx. MAIN OUTCOME MEASURES: The incidence of NSP cultured from the middle ears and nasopharynx of recruited subjects with the use of the minimum inhibitory concentration break points for penicillin susceptibility recommended by the National Committee for Clinical Laboratory Standards. RESULTS: S. pneumoniae was identified in at least 1 site from 23 of 300 study subjects (7.6%); of these 23, 12 case subjects (52.2%) harbored NSP. Of the risk factors assessed by preoperative questionnaire, only younger age was associated with NSP colonization (P < 0.0001). Of the six oral cephalosporins studied, cefpodoxime and cefuroxime showed good in vitro activity against S. pneumoniae isolates with intermediate penicillin resistance. CONCLUSIONS: Children with chronic otitis media undergoing tube placement may carry NSP and provide a means of monitoring the incidence of NSP and antibiotic susceptibilities for children with ear infections in their communities. Younger age is a risk factor for NSP carriage in this population.

Costs associated with tuberculosis control programs at hospitals caring for children.

OBJECTIVE: No data are available on the costs of implementing infection control measures for the control of Mycobacterium tuberculosis (MTB) in pediatric settings. In this study we determined the cost of MTB control measures at three hospitals caring for children. DESIGN: Infection control and tuberculosis (TB) coordinators obtained cost data retrospectively for the years 1994 to 1995 for tuberculin skin test programs, respiratory protection programs and the retrofit or new construction of environmental controls in pediatric settings. SETTING: Two pediatric hospitals and one pediatric ward in a large tertiary care hospital. RESULTS: Total expenditures for TB controls ranged from $15270 to $28158 for the 2-year study period. Engineering controls involved the largest capital outlay at two of three facilities. Average yearly tuberculin skin test costs ranged from $949 to $12504/hospital. Respiratory protection programs cost from $480 to $1680 during the 2-year study period. CONCLUSIONS: Costs associated with implementing control measures varied slightly by hospital but were less than those incurred by hospitals caring for adults. These costs represent improvements made to upgrade selected aspects of hospital TB control programs, not the cost of an optimal TB control program. Optimal TB control programs in pediatric settings have yet to be described.

Risk factors for Candida species colonization of neonatal intensive care unit patients.

BACKGROUND: Candida spp. are increasingly important pathogens in neonatal intensive care units (NICU). Prior colonization is a major risk factor for candidemia, but few studies have focused on risk factors for colonization, particularly in NICU patients. METHODS: A prospective, multicenter cohort study was performed in six NICUs to determine risk factors for Candida colonization. Infant gastrointestinal tracts were cultured on admission and weekly until NICU discharge and health care worker hands were cultured monthly for Candida spp. RESULTS: The prevalence of Candida spp. colonization was 23% (486 of 2157 infants); 299 (14%), 151 (7%) and 74 (3%) were colonized with Candida albicans, Candida parapsilosis and other Candida spp., respectively. Multiple logistic regression analysis adjusting for length of stay, birth weight < or = 1000 g and gestational age < 32 weeks revealed that use of third generation cephalosporins was associated with either C. albicans (155 incident cases) or C. parapsilosis (104 incident cases) colonization. Use of central venous catheters or intravenous lipids were risk factors for C. albicans, whereas delivery by cesarean section was protective. Use of H2 blockers was an independent risk factor for C. parapsilosis. Of 2989 cultures from health care workers' hands, 150 (5%) were positive for C. albicans and 575 (19%) for C. parapsilosis, but carriage rates did not correlate with NICU site-specific rates for infant colonization. CONCLUSIONS: We speculate that NICU patients acquire Candida spp., particularly C. parapsilosis, from the hands of health care workers. H2 blockers, third generation cephalosporins and delayed enteral feedings alter gastrointestinal tract ecology, thereby facilitating colonization.

Risk factors for candidemia in Neonatal Intensive Care Unit patients. The National Epidemiology of Mycosis Survey study group.

BACKGROUND: Candida species are important nosocomial pathogens in neonatal intensive care unit (NICU) patients. METHODS: A prospective cohort study was performed in six geographically diverse NICUs from 1993 to 1995 to determine the incidence of and risk factors for candidemia, including the role of gastrointestinal (GI) tract colonization. Study procedures included rectal swabs to detect fungal colonization and active surveillance to identify risk factors for candidemia. Candida strains obtained from the GI tract and blood were analyzed by pulsed field gel electrophoresis to determine whether colonizing strains caused candidemia. RESULTS: In all, 2,847 infants were enrolled and 35 (1.2%) developed candidemia (12.3 cases per 1,000 patient discharges or 0.63 case per 1,000 catheter days) including 23 of 421 (5.5%) babies < or =1,000 g. After adjusting for birth weight and abdominal surgery, forward multivariate logistic regression analysis demonstrated significant risk factors, including gestational age <32 weeks, 5-min Apgar <5; shock, disseminated intravascular coagulopathy, prior use of intralipid, parenteral nutrition, central venous catheters, H2 blockers, intubation or length of stay > 7 days before candidemia (P < 0.05). Catheters, steroids and GI tract colonization were not independent risk factors, but GI tract colonization preceded candidemia in 15 of 35 (43%) case patients. CONCLUSIONS: Candida spp. are an important cause of late onset sepsis in NICU patients. The incidence of candidemia might be decreased by the judicious use of treatments identified as risk factors and avoiding H2 blockers.

Persistence of immunity to varicella-zoster virus after vaccination of healthcare workers.

OBJECTIVE: Varicella-zoster virus (VZV) vaccine is recommended to protect susceptible healthcare workers (HCWs) from serious disease and to prevent nosocomial spread of VZV. We evaluated clinical outcomes and serological responses in HCWs after immunization with live attenuated VZV vaccine. DESIGN: Vaccinees were immunized from 1979 to 1998 during VZV vaccine trials, as well as after licensure, and followed prospectively for 1 month to 20.6 (mean 4.6) years after vaccination. Sera were tested by fluorescent antibody to membrane antigen (FAMA), latex agglutination (LA), and enzyme-linked immunoassay (EIA) to detect VZV-specific antibodies. STUDY PARTICIPANTS: The median age of the 120 HCWs was 26 years; 51 (42%) were males. INTERVENTIONS: Ninety eight (82%) of these study subjects received vaccine prepared by Merck and 22 (18%) by SmithKline Beecham; 25, 81, and 14 vaccinees received one dose, two doses, and three doses, respectively. RESULTS: The crude attack rate was 10%; 12 of 120 HCWs developed chickenpox 6 months to 8.4 years after vaccination. The attack rates following household and hospital exposures were 18% (4/22) and 8% (6/72), respectively. All resulting illness was mild to moderate (mean 40 vesicles). Seroconversion after vaccination was documented by FAMA in 96% of HCWs, although 31% lost detectable antibodies. Compared with FAMA, LA and EIA were 82% and 74% sensitive and 94% and 89% specific, respectively. CONCLUSIONS: The VZV vaccine effectively protected HCWs from varicella, particularly from serious disease. Currently available serological tests are not optimal, and improved assays are needed.

Nosocomial rotavirus in a pediatric hospital.

We describe a nosocomial rotavirus outbreak among pediatric cardiology patients and the impact of a prospective, laboratory-based surveillance program for rotavirus in our university-affiliated, quartenary-care pediatric hospital in New York City. Improved compliance with infection control and case-finding among patients and healthcare workers halted the outbreak.

Comparison of two commercial systems (Vitek and MicroScan-WalkAway) for antimicrobial susceptibility testing of Pseudomonas aeruginosa isolates from cystic fibrosis patients.

Antimicrobial susceptibility testing of cystic fibrosis (CF) isolates of Pseudomonas aeruginosa is difficult because the organisms are often mucoid and slow-growing. This study of 498 CF strains examined the correlation of results derived from two commonly used commercial systems (Vitek, MicroScan-WalkAway) with a reference method for 10 antimicrobials. Correlation to reference results was unacceptably low for all agents and both commercial systems had a high rate of very major (false-susceptible) errors. Although mucoid strains produced a 4.8% greater intermethod error, it was not markedly different than non-mucoid strains for the Vitek System. Overall, these tested commercial systems performed poorly for CF isolates in contrast to earlier reported, high correlations with the reference methods (broth microdilution frozen panels and agar dilution) of the National Committee for Clinical Laboratory Standards, the standardized disk diffusion test, and the Etest (AB BIODISK, Solna, Sweden).