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.

Developing clinical decision support within a commercial electronic health record system to improve antimicrobial prescribing in the neonatal ICU

OBJECTIVE

To develop and implement a clinical decision support (CDS) tool to improve antibiotic prescribing in neonatal intensive care units (NICUs) and to evaluate user acceptance of the CDS tool.

METHODS

Following sociotechnical analysis of NICU prescribing processes, a CDS tool for empiric and targeted antimicrobial therapy for healthcare-associated infections (HAIs) was developed and incorporated into a commercial electronic health record (EHR) in two NICUs. User logs were reviewed and NICU prescribers were surveyed for their perceptions of the CDS tool.

RESULTS

The CDS tool aggregated selected laboratory results, including culture results, to make treatment recommendations for common clinical scenarios. From July 2010 to May 2012, 1,303 CDS activations for 452 patients occurred representing 22% of patients prescribed antibiotics during this period. While NICU clinicians viewed two culture results per tool activation, prescribing recommendations were viewed during only 15% of activations. Most (63%) survey respondents were aware of the CDS tool, but fewer (37%) used it during their most recent NICU rotation. Respondents considered the most useful features to be summarized culture results (43%) and antibiotic recommendations (48%).

DISCUSSION

During the study period, the CDS tool functionality was hindered by EHR upgrades, implementation of a new laboratory information system, and changes to antimicrobial testing methodologies. Loss of functionality may have reduced viewing antibiotic recommendations. In contrast, viewing culture results was frequently performed, likely because this feature was perceived as useful and functionality was preserved.

CONCLUSION

To improve CDS tool visibility and usefulness, we recommend early user and information technology team involvement which would facilitate use and mitigate implementation challenges.

Antimicrobial susceptibility and molecular typing of MRSA in cystic fibrosis

OBJECTIVES

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patients in the United States is approximately 25%. Little is known about the relative proportion of hospital- versus community-associated strains or the antimicrobial susceptibility of MRSA in different CF centers. We hypothesized that the majority of MRSA isolates obtained from children with CF are those endemic in the hospital and that those associated with community acquisition (SCCmec IV) would be more resistant than typically seen in non-CF MRSA isolates.

METHODS

We studied MRSA strains from seven pediatric CF centers to determine the clonal distribution based on DNA sequencing of the staphylococcal protein A gene (spa typing), the type of staphylococcal chromosomal cassette mec (SCCmec), and the proportion of strains with Panton-Valentine leukocidin (PVL). Antimicrobial susceptibility to systemic and topical antibiotics was compared between different MRSA types.

RESULTS

We analyzed 277 MRSA isolates from unique patients (mean age 11.15 ± 4.77 years, 55% male). Seventy % of isolates were SCCmec II PVL negative and the remainder SCCmec IV. Overall 17% MRSA strains were PVL positive (all SCCmec IV). Spa typing of 118 isolates showed most of the SCCmec II strains being t002, while SCCmec IV PVL positive isolates were t008, and SCCmec IV PVL negative isolates represented a variety of spa-types. The proportions of SCCmec II strains and spa-types were similar among centers. Overall rates of resistance to trimethoprim-sulfamethoxazole (4%), tetracycline (7%), tigecycline (0.4%), linezolid (0.4%) as well as fosfomycin (0.4%), fusidic acid (3%), and mupirocin (1%) were low. No strains were resistant to vancomycin. SCCmec II strains had higher rates of resistance to ciprofloxacin and clindamycin (P < 0.001) than SCCmec IV strains.

CONCLUSIONS

In this U.S. study, most MRSA isolates in the pediatric CF population were SCCmec II PVL negative. Rates of resistance were low, including to older and orally available antibiotics such as trimethoprim-sulfamethoxazole.

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.

The epidemiology of methicillin-susceptible and methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit, 2000-2007

OBJECTIVE

To assess the epidemiology of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) infections in a neonatal intensive care unit (NICU).

STUDY DESIGN

A retrospective chart review was conducted from 2000-2007; demographic and clinical characteristics of infected infants and crude mortality were assessed.

RESULTS

During the study period, there were 123 infections caused by MSSA and 49 infections caused by MRSA. Although the types of infections caused by MSSA and MRSA were similar, infants with MRSA infections were younger at clinical presentation than infants with MSSA infections (P=0.03). The overall rate of S. aureus infections was approximately 15-30 per 1000 patient-admissions. The rate of bacteremia and skin and soft tissue infections remained stable over time. Among extremely low birth weight infants (birth weight <1000 g), 4.8 and 1.8% developed an infection caused by MSSA or MRSA, respectively. Infections occurred in a bimodal distribution of birth weight; 53% of infections occurred in extremely low birth weight infants and 27% occurred among term infants birth weight >or=2500 g, many of whom underwent surgical procedures.

CONCLUSIONS

MSSA and MRSA remain significant pathogens in the NICU, particularly for extremely premature infants and term infants undergoing surgery. Further work should investigate infection control strategies that effectively target the highest risk groups and determine if vertical transmission of MRSA is responsible for the younger age at presentation of infection.

Development of a statewide collaborative to decrease NICU central line-associated bloodstream infections

OBJECTIVE

To characterize hospital-acquired bloodstream infection rates among New York State's 19 regional referral NICUs (at regional perinatal centers; RPCs) and develop strategies to promote best practices to reduce central line-associated bloodstream infections (CLABSIs).

STUDY DESIGN

During 2006 and 2007, RPC NICUs reported bloodstream infections, patient-days and central line-days to the Department of Health, and shared their results. Aiming to improve, participants created a central line-care bundle based on visiting a potentially best performing NICU and reviewing the literature.

RESULT

All 19 RPCs participated in this quality initiative, contributing 218,096 patient-days and 56,911 central line-days of observation. Individual RPC nosocomial sepsis infection (NI) rates ranged from 1.0 to 5.8 NIs per 1000 patient-days (2006), and CLABSI rates ranged from 2.6 to 15.1 CLABSIs per 1000 central line-days (2007). A six-fold rate variation among RPC NICUs was observed. Participants unanimously approved a level-1 evidence-based central line-care bundle.

CONCLUSION

Individual RPC rates and consequent morbidity and resource use attributable to these infections were substantial and varied greatly. No center was without infections. It is hoped that the cooperation and accountability exhibited by the RPCs will result in a major network for characterizing performance and improving outcomes.

Rational treatment of pulmonary infections in patients with cystic fibrosis

The life expectancy of patients with cystic fibrosis has increased markedly during the past two decades due in large part to improved clinical care, including the use of more effective antimicrobial agents for Pseudomonas. However, the chronic lung disease of CF remains the principal cause of mortality. A growing understanding of the complex interactions between infection and inflammation has led to new approaches for treatment, including chronic use of aerosolized antibiotics, particularly tobramycin, in patients known to be colonized/infected with P. aeruginosa and anti-inflammatory treatments to slow the progression of lung disease.

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.

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.

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.

Identification and antimicrobial susceptibility of Alcaligenes xylosoxidans isolated from patients with cystic fibrosis

In the past decade, potential pathogens, including Alcaligenes species, have been increasingly recovered from cystic fibrosis (CF) patients. Accurate identification of multiply antibiotic-resistant gram-negative bacilli is critical to understanding the epidemiology and clinical implications of emerging pathogens in CF. We examined the frequency of correct identification of Alcaligenes spp. by microbiology laboratories affiliated with American CF patient care centers. Selective media, an exotoxin A probe for Pseudomonas aeruginosa, and a commercial identification assay, API 20 NE, were used for identification. The activity of antimicrobial agents against these clinical isolates was determined. A total of 106 strains from 78 patients from 49 CF centers in 22 states were studied. Most (89%) were correctly identified by the referring laboratories as Alcaligenes xylosoxidans. However, 12 (11%) strains were misidentified; these were found to be P. aeruginosa (n = 10), Stenotrophomonas maltophilia (n = 1), and Burkholderia cepacia (n = 1). Minocycline, imipenem, meropenem, piperacillin, and piperacillin-tazobactam were the most active since 51, 59, 51, 50, and 55% of strains, respectively, were inhibited. High concentrations of colistin (100 and 200 microg/ml) inhibited 92% of strains. Chloramphenicol paired with minocycline and ciprofloxacin paired with either imipenem or meropenem were the most active combinations and inhibited 40 and 32%, respectively, of strains. Selective media and biochemical identification proved to be useful strategies for distinguishing A. xylosoxidans from other CF pathogens. Standards for processing CF specimens should be developed, and the optimal method for antimicrobial susceptibility testing of A. xylosoxidans should be determined.

Cathelicidin peptides inhibit multiply antibiotic-resistant pathogens from patients with cystic fibrosis

Endogenous peptide antibiotics are under investigation as inhaled therapeutic agents for cystic fibrosis (CF) lung disease. The bactericidal activities of five cathelicidin peptides (LL37 [human], CAP18 [rabbit], mCRAMP [mouse], rCRAMP [rat], and SMAP29 [sheep]), three novel alpha-helical peptides derived from SMAP29 and termed ovispirins (OV-1, OV-2, and OV-3), and two derivatives of CAP18 were tested by broth microdilution assays. Their MICs were determined for multiply antibiotic-resistant Pseudomonas aeruginosa (n = 24), Burkholderia cepacia (n = 5), Achromobacter xylosoxidans (n = 5), and Stenotrophomonas maltophilia (n = 5) strains isolated from CF patients. SMAP29 was most active and inhibited mucoid and nonmucoid P. aeruginosa strains (MIC, 0.06 to 8 microg/ml). OV-1, OV-2, and OV-3 were nearly as active (MIC, 0.03 to 16 microg/ml), but CAP18 (MIC, 1.0 to 32 microg/ml), CAP18-18 (MIC, 1.0 to >32 microg/ml), and CAP18-22 (MIC, 0.5 to 32 microg/ml) had variable activities. LL37, mCRAMP, and rCRAMP were least active against the clinical isolates studied (MIC, 1.0 to >32 microg/ml). Peptides had modest activities against S. maltophilia and A. xylosoxidans (MIC range, 1.0 to > 32 microg/ml), but none inhibited B. cepacia. However, CF sputum inhibited the activity of SMAP29 substantially. The effects of peptides on bacterial cell membranes and eukaryotic cells were examined by scanning electron microscopy and by measuring transepithelial cell resistance, respectively. SMAP29 caused the appearance of bacterial membrane blebs within 1 min, killed P. aeruginosa within 1 h, and caused a dose-dependent, reversible decrease in transepithelial resistance within 5 h. The tested cathelicidin-derived peptides represent a novel class of antimicrobial agents and warrant further development as prophylactic or therapeutic agents for CF lung disease.

Prevalence of infectious diseases among internationally adopted children

OBJECTIVE

Internationally adopted children are at increased risk of infections acquired in their country of origin. Ongoing surveillance of this unique population is needed to detect changing epidemiology and provide appropriate care.

METHODS

We performed a retrospective cohort study of 504 children adopted from abroad and evaluated from 1997 to 1998 to determine the prevalence of and factors associated with various infectious diseases.

RESULTS

The mean age of the study participants at medical evaluation was 1.6 years; 71% were girls, and they were adopted from 16 countries, including China (48%), Russia (31%), Southeast Asia (8%), Eastern Europe (8%), and Latin America (5%). Overall, 75 (19%) of 404 children tested had tuberculin skin tests >/=10 mm, but all had normal chest radiographs. BCG vaccination (odds ratio [OR]: 7.37; 95% confidence interval [CI]: 3.29, 17.16) and being Russian born (OR: 2.90; 95% CI: 1.68, 5.00) were risk factors for latent tuberculosis infection. Fourteen (2.8%) children had detectable hepatitis B surface antigen, but no child had active hepatitis C, human immunodeficiency virus, or syphilis. Giardia lamblia antigen was detected in 87 (19%) of 461 tested children, and such children were older (mean: 22 months vs 15.5 months) and more likely to have been born in Eastern Europe (OR: 2.82; 95% CI: 1.70, 4.68).

CONCLUSIONS

We demonstrated increased rates of latent tuberculosis infection and G lamblia infection than previously reported. Thus, ongoing surveillance of internationally adopted children, international trends in infectious diseases, and appropriate screening will ensure the long-term health of adopted children as well as their families.

Risk factors for candidal bloodstream infections in surgical intensive care unit patients: the NEMIS prospective multicenter study. The National Epidemiology of Mycosis Survey

To assess risk factors for development of candidal blood stream infections (CBSIs), a prospective cohort study was performed at 6 sites that involved all patients admitted to the surgical intensive care unit (SICU) for >48 h over a 2-year period. Among 4276 such patients, 42 CBSIs occurred (9.82 CBSIs per 1000 admissions). The overall incidence was 0.98 CBSIs per 1000 patient days and 1.42 per 1000 SICU days with a central venous catheter in place. In multivariate analysis, factors independently associated with increased risk of CBSI included prior surgery (relative risk [RR], 7.3), acute renal failure (RR, 4.2), receipt of parenteral nutrition (RR, 3.6), and, for patients who had undergone surgery, presence of a triple lumen catheter (RR, 5.4). Receipt of an antifungal agent was associated with decreased risk (RR, 0.3). Prospective clinical studies are needed to identify which antifungal agents are most protective and which high-risk patients will benefit from antifungal prophylaxis.

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.

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.

Risk factors for latent tuberculosis infection among children in New York City

OBJECTIVE

Although identification and appropriate treatment of children with latent tuberculosis (TB) infection (LTBI) is considered critical to the control and elimination of TB in the United States, there are limited data on risk factors for LTBI in pediatric populations.

METHODS

To further improve targeted screening for LTBI, we performed a matched case-control study from September 1996 to December 1998. We actively surveyed 24 primary care clinics serving Northern Manhattan and Harlem twice monthly for case participants 1 to 5 years old with LTBI, defined as a child with a Mantoux tuberculin skin test (TST) >/=10 mm and a normal chest radiograph. Two age- and clinic-matched control participants with TSTs equal to 0 mm were enrolled per case. To determine risk factors for LTBI, a bilingual research worker reviewed the medical records of study participants and administered a questionnaire to the parents of participants.

RESULTS

We enrolled 96 cases and 192 controls whom did not differ by age, gender, ethnicity, and race; overall, the mean age of participants was 2.9 years, 51% were male, 80% were Hispanic, and 9% black. Logistic regression analysis demonstrated that contact with an adult with active TB, foreign birth, foreign travel, and a relative with a positive TST were predictive of case status. In contrast, a history of a previous negative TST proved protective and BCG immunization was not an independent risk factor for a positive TST, suggesting that boosting was not important in this population.

CONCLUSIONS

We identified several risk factors for LTBI in children that can be used to refine targeted surveillance for TB among Hispanic immigrant populations in the United States.

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).

Endemic Pseudomonas aeruginosa infection in a neonatal intensive care unit

BACKGROUND

Nosocomial infections due to Pseudomonas aeruginosa have been well described, but the environmental reservoir of the organism varies. We conducted an epidemiologic and molecular investigation of endemic P. aeruginosa infection among infants in a neonatal intensive care unit that was associated with carriage of the organisms on the hands of health care workers.

METHODS

In August 1998, colonization or infection with P. aeruginosa was identified in six infants. Surveillance cultures for P. aeruginosa were obtained from the other 27 infants in the unit, and possible environmental reservoirs were also assessed. The hands of health care workers were inspected and cultured, and risk factors for P. aeruginosa colonization were evaluated. Isolates were analyzed for clonality by pulsed-field gel electrophoresis.

RESULTS

Surveillance cultures showed that three additional infants were colonized with P. aeruginosa. Cultures of environmental specimens were negative, but cultures of the hands of 10 of 165 health care workers (6 percent) were positive for P. aeruginosa. Increasing age (P=0.05) and a history of the use of artificial fingernails or nail wraps (P=0.03) were both risk factors for colonization of the hands. From January 1997 to August 1998, 49 infants were infected or colonized with P. aeruginosa. Pulsed-field gel electrophoresis demonstrated that 17 of these infants and 1 health care worker who had onychomycosis had the same clone. Infants who were exposed to this health care worker in August 1998 were at greater risk of having this clone than infants who were not exposed to this health care worker (odds ratio, 41.2; 95 percent confidence interval, 1.8 to 940.0; P=0.006).

CONCLUSIONS

An increased rate of infection and colonization with P. aeruginosa among infants in neonatal intensive care units should be investigated by assessing potential reservoirs, including environmental sources as well as patients and health care workers.

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.

Comparison of agar diffusion methodologies for antimicrobial susceptibility testing of Pseudomonas aeruginosa isolates from cystic fibrosis patients

Pseudomonas aeruginosa is the most common pathogen infecting the lungs of patients with cystic fibrosis (CF). Improved antimicrobial chemotherapy has significantly increased the life expectancy of these patients. However, accurate susceptibility testing of P. aeruginosa isolates from CF sputum may be difficult because the organisms are often mucoid and slow growing. This study of 597 CF isolates of P. aeruginosa examined the correlation of disk diffusion and Etest (AB BIODISK, Solna, Sweden) results with a reference broth microdilution method. The rates of interpretive errors for 12 commonly used antipseudomonal antimicrobials were determined. The disk diffusion method correlated well (zone diameter versus MIC) for all of the agents tested. However, for mucoid isolates, correlation coefficients (r values) for piperacillin, piperacillin-tazobactam, and meropenem were <0.80. The Etest correlation with reference broth microdilution results (MIC versus MIC) was acceptable for all of the agents tested, for both mucoid and nonmucoid isolates. Category interpretation errors were similar for the disk diffusion and Etest methods with 0.4 and 0.1%, respectively, very major errors (false susceptibility) and 1.1 and 2.2% major errors (false resistance). Overall, both agar diffusion methods appear to be broadly acceptable for routine clinical use in susceptibility testing of CF isolates of P. aeruginosa.

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.

Assessment of alternative hand hygiene regimens to improve skin health among neonatal intensive care unit nurses

OBJECTIVE

The frequent handwashing and gloving required in high-risk, high-volume patient care areas such as critical care units damages skin of the hands. The purpose of this exploratory study was to compare 2 hand care regimens (traditional antiseptic wash with chlorhexidine-containing detergent versus mild soap wash with subsequent alcohol-based rinse for degerming as necessary) in a neonatal intensive care unit (NICU).

DESIGN

Prospective, quasi-experimental, random assignment.

SETTING

One NICU (47 beds) in a New York City children's hospital.

SUBJECTS

Sixteen full-time NICU nurses.

OUTCOME MEASURES

Microbial flora and skin condition of hands.

INTERVENTION

Nurses were randomly assigned to one of the 2 hand care regimens.

RESULTS

No significant differences in microbial counts or types of organisms from hands of staff were found, but after 2 weeks nurses in the mild soap and alcohol group had significant improvements in their skin condition (P =.005).

CONCLUSIONS

Use of a mild soap for cleaning and an alcohol-based product for degerming may offer an acceptable alternative to the traditional antiseptic handwash and may reduce skin damage to health care professionals' hands.

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.

Elucidating the origins of nosocomial infections with Candida albicans by DNA fingerprinting with the complex probe Ca3

Computer-assisted DNA fingerprinting with the complex probe Ca3 has been used to analyze the relatedness of isolates collected from individuals with nosocomial bloodstream infections (BSIs) and hospital care workers (HCWs) in the surgical and neonatal intensive care units (ICUs) of four hospitals. The results demonstrate that for the majority of patients (90%), isolates collected from commensal sites before and after collection of a BSI isolate were highly similar or identical to the BSI isolate. In addition, the average similarity coefficient for BSI isolates was similar to that for unrelated control isolates. However, the cluster characteristics of BSI isolates in dendrograms generated for each hospital compared to those of unrelated control isolates in a dendrogram demonstrated a higher degree of clustering of the former. In addition, a higher degree of clustering was observed in mixed dendrograms for HCV isolates and BSI isolates for each of the four test hospitals. In most cases, HCW isolates from an ICU were collected after the related BSI isolate, but in a few cases, the reverse was true. Although the results demonstrate that single, dominant endemic strains are not responsible for nosocomial BSIs in neonatal ICUs and surgical ICUs, they suggest that multiple endemic strains may be responsible for a significant number of cases. The results also suggest that cross-contamination occurs between patients and HCWs and between HCWs in the same ICU and in different ICUs. The temporal sequence of isolation also suggests that in the majority of cases HCWs are contaminated by isolates from colonized patients, but in a significant minority, the reverse is true. The results of this study provide the framework for a strategy for more definitive testing of the origins of Candida albicans strains responsible for nosocomial infections.

Evaluation of reference dilution test methods for antimicrobial susceptibility testing of Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis

The development of multidrug-resistant Pseudomonas aeruginosa in patients with cystic fibrosis (CF) is most likely a consequence of increasing life expectancy and more prolonged exposure to antibiotics. The optimal method for antibiotic susceptibility testing of CF strains, particularly mucoid P. aeruginosa strains, is unknown. Antimicrobial susceptibilities of 48 CF strains (25 mucoid) and 50 non-CF strains to 12 anti-Pseudomonas agents were tested by both agar dilution and commercially custom-prepared broth microdilution plates (PML Microbiologicals, Portland, Oreg.) in three laboratories simultaneously to determine if broth microdilution could substitute for agar dilution as the reference method in subsequent studies. Comparison of MICs generated by agar dilution and broth microdilution demonstrated correlation coefficients (r) exceeding 0.85 for all agents tested; correlation was excellent for aminoglycosides (r >/= 0.92) and very good for beta-lactam agents including agents paired with a beta-lactamase inhibitor (r >/= 0.87) and for ciprofloxacin (r = 0.86). Correlation was not improved by 48-h readings, but correlation between 24- and 48-h readings ranged between 0.91 and 0.98 for both methods. Interlaboratory variations were minimal, as the percentage of acceptable variations was 94% for both methods, and serious discords were infrequent (<2% of comparisons). However, CF strains were more likely to have serious discords than were non-CF strains (P < 0. 0001), although mucoid strains were not more likely to have serious discords than were nonmucoid strains. In this study, MICs determined by custom-prepared broth microdilution compared favorably with MICs determined by agar dilution. Thus, this broth microdilution assay can serve as a reference method and facilitate future studies to determine the optimal method for antibiotic susceptibility testing of CF strains.

National epidemiology of mycoses survey (NEMIS): variations in rates of bloodstream infections due to Candida species in seven surgical intensive care units and six neonatal intensive care units

Candida species are the fourth most frequent cause of nosocomial bloodstream infections, and 25%-50% occur in critical care units. During an 18-month prospective study period, all patients admitted for > or = 72 hours to the surgical (SICUs) or neonatal intensive care units (NICUs) at each of the participant institutions were followed daily. Among 4,276 patients admitted to the seven SICUs in six centers, there were 42 nosocomial bloodstream infections due to Candida species (9.8/1,000 admissions; 0.99/1,000 patient-days). Of 2,847 babies admitted to the six NICUs, 35 acquired a nosocomial bloodstream infection due to Candida species (12.3/1,000 admissions; 0.64/1,000 patient-days). The following were the most commonly isolated Candida species causing bloodstream infections in the SICU: Candida albicans, 48%; Candida glabrata, 24%; Candida tropicalis, 19%; Candida parapsilosis, 7%; Candida species not otherwise specified, 2%. In the NICU the distribution was as follows: C. albicans, 63%; C. glabrata, 6%; C. parapsilosis, 29%; other, 3%. Of the patients, 30%-50% developed incidental stool colonization, 23% of SICU patients developed incidental urine colonization, and one-third of SICU health care workers' hands were positive for Candida species.

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.

Penicillin-nonsusceptible pneumococcus in acute otitis media in New York City

OBJECTIVE

To determine the proportion of children with acute otitis media (AOM) presenting in our catchment area in New York City who were infected with nonsusceptible Streptococcus pneumoniae and to determine the susceptibility of these organisms to penicillins and other antibiotics commonly used to treat AOM.

SETTING

Ambulatory clinics and the emergency department of a tertiary care, inner-city medical center.

PATIENTS

During a 2-year period from 1993 to 1995, 115 children (aged 6 months to 12 years) with AOM underwent tympanocentesis. Patients did not receive antibiotics for at least 1 week before tympanocentesis.

RESULTS

Thirty-one children were infected with S pneumoniae, and 83.9% of isolates were susceptible to penicillin. Of the 16.1% strains that were nonsusceptible, most (4 of 5 strains) were intermediately resistant, and only 1 exhibited high-level resistance to penicillin. Of all the cephalosporins tested, only cefotaxime had consistent activity against the intermediately resistant strains. Notably, all nonsusceptible pneumococci were inhibited by macrolides.

CONCLUSIONS

This study provides unique reference data for nonsusceptible Streptococcus pneumoniae in children with AOM and documents that newer cephalosporin agents are not active against all of these 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.

Genital chlamydial disease in an urban, primarily Hispanic, family planning clinic

BACKGROUND AND OBJECTIVES

Although chlamydia is a well-studied disease, little is known about the rates of genital chlamydial disease among female Hispanics in urban family planning clinics.

GOALS

To determine the prevalence of women with chlamydia in two clinic populations during 1994. We also sought to describe previously identified and novel risk factors for chlamydial disease in this unique population.

STUDY DESIGN

We conducted a retrospective case-control analysis in two community clinics in the Washington Heights section of New York City.

RESULTS

In 1994, 4,190 screening tests were done for Chlamydia trachomatis in these clinics, and the prevalence of positive tests was 5.4% (227/4,190). The mean age of the women screened was 19.2 years and most were of Hispanic origin (76%), students (51%), and received Medicaid (61%). Risk factors found to be associated with C. trachomatis infection included young age; earlier age at first coitus; pregnancy at the time of chlamydia screening; concurrent gonorrheal infection; and the clinical findings of cervical abnormalities, vaginal discharge, and adnexal tenderness. Hormonal contraception appeared to be protective against chlamydial infection (odds ratio, 0.36%; confidence interval, 0.17-0.77).

CONCLUSION

Sexually transmitted diseases were common in our population because 5.4% of the women screened had chlamydial infection and 1.5% had concurrent gonorrheal infection. Our study confirmed risk factors established in other populations. These data support the need for enhanced screening efforts for chlamydia to decrease the prevalence of disease in our population.

National epidemiology of mycoses survey: a multicenter study of strain variation and antifungal susceptibility among isolates of Candida species

The National Epidemiology of Mycoses Survey (NEMIS) involves six academic centers studying fungal infections in surgical and neonatal intensive care unit (ICU) patients. We studied variation in species and strain distribution and anti-fungal susceptibility of 408 isolates of Candida spp. Candida spp. were isolated from blood, other normally sterile site cultures, abscesses, wounds, catheters, and tissue biopsies of 141 patients hospitalized in the surgical (107 patients) and neonatal (34 patients) ICUs of medical centers located in Oregon, Iowa, California, Texas, Georgia, and New York. Isolates were also obtained from selected colonized patients (16 patients) and the hands of health care workers (27 individuals). DNA typing was performed using pulsed field gel electrophoresis, and antifungal susceptibility to amphotericin B, 5-fluorocytosine, fluconazole, and itraconazole was determined using National Committee for Clinical Laboratory Standards (NCCLS) methods. Important variation in susceptibility to itraconazole and fluconazole was noted: MICs of itraconazole ranged from 0.25 microgram/mL (MIC90) in Texas to 2.0 micrograms/mL (MIC90) in New York. Similarly, the MIC90 for fluconazole was higher for isolates from New York (64 micrograms/mL) compared to the other sites (8-16 micrograms/mL). In general, DNA typing revealed patient-unique strains; however, there were 13 instances of possible cross-infection noted in 5 of the medical centers. Notably, 9 of the 13 clusters involved species of Candida other than C. albicans. Potential transmission from patient-to-patient (C. albicans, C. glabrata, C. tropicalis, C. parapsilosis) and health care worker-to-patient (C. albicans, C. parapsilosis, C. krusei) was noted in both surgical ICU and neonatal ICU settings. These data provide further insight into the epidemiology of nosocomial candidiasis in the ICU setting.

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.

Antibiotic susceptibility of multiply resistant Pseudomonas aeruginosa isolated from patients with cystic fibrosis, including candidates for transplantation

Chronic lung disease caused by antibiotic-resistant Pseudomonas aeruginosa in patients with cystic fibrosis (CF) is difficult to treat, especially in those who are lung transplantation candidates. Analysis of antibiotic susceptibility and synergy studies of 1,296 isolates revealed that 172 (13.3%) were multiply resistant (i.e., resistant to two or more classes of anti-Pseudomonas agents). beta-Lactam agents (including imipenem and aztreonam) or aminoglycosides inhibited only 11% of the multiply resistant strains, while ciprofloxacin inhibited 34%. High concentrations of tobramycin and gentamicin (200 micrograms/mL), achievable by aerosol administration, inhibited 95% of isolates and overwhelmed permeability-resistance mechanisms. Antimicrobial pairs tested in checkerboard dilutions of clinically achievable drug concentrations inhibited 75% of the multiply resistant strains. On average, three additive and 2.4 synergistic pairs of antimicrobial agents had activity per strain. Transplantation candidates were older than nontransplantation candidates (P = .034), and isolates from transplantation candidates were less likely to be inhibited by antibiotic combinations (P < .001). Administration of aerosolized aminoglycosides and synergy testing of antimicrobial combinations may represent viable therapeutic options for patients with CF.

Binding of Pseudomonas aeruginosa to respiratory epithelial cells from patients with various mutations in the cystic fibrosis transmembrane regulator

OBJECTIVE

To determine whether there is an association between mutations of the cystic fibrosis transmembrane regulator (CFTR) and the predilection of patients with cystic fibrosis (CF) for Pseudomonas aeruginosa infection.

METHOD

We quantified the adherence of P. aeruginosa PA01, labeled with sulfur 35-methionine, to epithelial monolayers derived from nasal scrapings of patients with specific CFTR mutations, and of carriers and normal subjects.

RESULTS

Adherence of P. aeruginosa to epithelial cells from patients with CF was significantly greater than to cells from either carriers (t = 2.94; p = 0.009) or normal subjects (t = 3.32; p = 0.004). Adherence to epithelial cells from patients with CF who were homozygous for the delta F508 mutation ranged from 12% to 35% (mean, 23.7%) of the added inoculum, which was significantly greater than the binding to cells from patients with other mutations, which ranged from 3% to 18% (mean, 9.4%; t = 3.71; p = 0.002), from heterozygote carriers (3% to 11%; mean, 7.9%; t = 4.87; p = 0.002), or from normal subjects (2% to 10%: mean, 7.0%; t = 5.21; p = 0.002).

CONCLUSION

Adherence to P. aeruginosa can be correlated with homozygosity for the delta 508 mutation; CFTR dysfunction may be one of the factors involved in the pathogenesis of pulmonary infection in CF.

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.

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.

Candida lusitaniae osteomyelitis in a premature infant

Candida lusitaniae is emerging as an opportunistic pathogen in premature infants. Treatment of C. lusitaniae is challenging due to frequent resistance of this organism to antifungal agents and lack of standardized susceptibility testing for fungi. We report the case of a premature infant with C. lusitaniae osteomyelitis in whom treatment was successful with 5-fluorocytosine and fluconazole.