Biomedical subjects

Fann Wu

Publications and source records attributed to Fann Wu.

14 recordsLinked to original sources

PubMed2005

Genetic relatedness of Staphylococcus epidermidis from infected infants and staff in the neonatal intensive care unit.

BACKGROUND: The genetic relatedness of Staphylococcus epidermidis associated with infections in infants and cultured from the hands of nurses was assessed. METHODS: From March 2001 to January 2002, infections caused by S. epidermidis were prospectively monitored. Participating nurses had hand cultures performed quarterly following hand hygiene. Pulsed-field gel electrophoresis was performed to determine genetic relatedness of strains from infants and nurses. RESULTS: During the study period, S. epidermidis caused 42 of 143 (29%) and 26 of 100 (26%) infant infections and was cultured from the clean hands of 51 of 61 (84%) and 53 of 58 (91%) nurses in neonatal intensive care unit (NICU)-1 and NICU-2, respectively. Fifty-eight clones of S. epidermidis were identified among 173 isolates typed: 38 of 173 isolates (22%) were unique clones detected in a single infant (n=10) or nurse (n=28); 42 of 173 (24%) isolates were defined as belonging to small cluster clones (n=15), ie, were detected in 2 to 4 nurses and/or infants; and 93 of 173 (54%) isolates belonged to large cluster clones (n=4), ie, detected in 7 to 64 nurses and/or infants. CONCLUSIONS: These data suggested that most S. epidermidis isolates were shared between infants and nurses. Hand hygiene alone is inadequate to prevent S. epidermidis infections, and additional strategies are needed to prevent cross transmission in NICU populations.

Carrier State↗

PubMed2005

Risk factors for candidemia in critically ill infants: a matched case-control study.

OBJECTIVE: To determine risk factors for late-onset candidemia among infants in the neonatal intensive care unit (NICU). STUDY DESIGN: We performed a matched case-control study from March 2001 to January 2003 in 2 level III-IV NICUs. Case subjects had candidemia diagnosed more than 48 hours after hospitalization. Control subjects (3 per case) were matched by study site, birth weight, study year, and date of enrollment. Potential risk factors included medical devices, medications, gastrointestinal (GI) pathology (congenital anomalies or necrotizing enterocolitis) and previous bacterial bloodstream infections (BSIs). RESULTS: Forty-five cases of candidemia occurred during the study period and accounted for 15% of BSIs. C. albicans caused 62% of infections (28/45); C. parapsilosis, 31% (14/45). Multivariate analysis revealed that catheter use (odds ratio [OR]=1.06 per day of use; 95% confidence interval [CI]=1.02 to 1.10), previous bacterial BSIs (OR=8.02; 95% CI=2.76 to 23.30) and GI pathology (OR=4.57; 95% CI=1.62 to 12.92) were significantly associated with candidemia. In all, 26/45 cases (58%) of candidemia occurred in infants who would not have qualified for fluconazole prophylaxis according to the Kaufman criteria. CONCLUSIONS: We confirmed previous risk factors (catheter-days) and identified novel risk factors (previous BSI and GI pathology) for candidemia in critically ill infants that could guide future targeted antifungal prophylaxis strategies.

Candidiasis↗

PubMed2005

Sexual behaviors and condom use of HIV-infected men and women of color attending a treatment and care clinic.

INTRODUCTION: Limited data are available regarding high-risk sexual behaviors among HIV-infected African Americans and Latinos who receive ongoing care in clinical settings. OBJECTIVES: To identify high-risk sexual behaviors and risk factors for consistent condom use and Chlamydia trachomatis (CT) infection. METHODS: Cross-sectional study data from interviewer-administered surveys and CT tests. RESULTS: Of 179 sexually active adults in the study, 35% had multiple sex partners, 37% had a partner with unknown HIV status and 49% used condoms consistently. Compared with men, women had fewer partners and were less likely to use condoms with partners of unknown HIV status. Men who have sex with men (MSM) had more partners and more partners with unknown HIV status compared with non-MSM. On multivariate analysis, drug use and having an HIV-infected partner were associated with less consistent condom use. CT prevalence was low (2%). CONCLUSION: This study identified ongoing high-risk sexual behaviors among a clinic-based group of African-American and Latino HIV-infected men and women. The clinical setting may be an ideal place for implementation of secondary prevention interventions.

Adult↗

PubMed2004

Molecular epidemiology of gram-negative bacilli from infected neonates and health care workers' hands in neonatal intensive care units.

We sought to characterize the molecular epidemiology of gram-negative bacilli (GNB) causing infections in infants and associated with carriage on nurses' hands after hand hygiene was performed. From March 2001 to January 2003, GNB caused 192 (34%) of 562 hospital-acquired infections in the 2 participating neonatal intensive care units (NICUs) and were isolated from the hands of 45 (38%) of 119 nurses. Five species--Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens and Enterobacter cloacae, all of which were typed by pulsed-field gel electrophoresis--caused 169 (88%) of 192 of GNB infections. Overall, 58% of infections were caused by unique strains not cultured from other infants or nurses, and 31% of infections were part of unrecognized molecular clusters. In contrast, only 9% of strains that caused infections were cultured from nurses' hands. These data suggest that practices in addition to hand hygiene are needed to prevent horizontal transmission of GNB in the NICU.

Adult↗

PubMed2004

Outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a neonatal intensive care unit linked to artificial nails.

BACKGROUND: From April to June 2001, an outbreak of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae infections was investigated in our neonatal intensive care unit. METHODS: Cultures of the gastrointestinal tracts of patients, the hands of healthcare workers (HCWs), and the environment were performed to detect potential reservoirs for ESBL-producing K. pneumoniae. Strains of K. pneumoniae were typed by pulsed-field gel electrophoresis using XbaI. A case-control study was performed to determine risk factors for acquisition of the outbreak clone (clone A); cases were infants infected or colonized with clone A and controls (3 per case) were infants with negative surveillance cultures. RESULTS: During the study period, 19 case-infants, of whom 13 were detected by surveillance cultures, harbored clone A. The overall attack rate for the outbreak strain was 45%; 9 of 19 infants presented with invasive disease (n = 6) or developed invasive disease (n = 3) after colonization was detected. Clone A was found on the hands of 2 HCWs, 1 of whom wore artificial nails, and on the designated stethoscope of a case-infant. Multiple logistic regression analysis revealed that length of stay per day (odds ratio [OR], 1.05; 95% confidence interval [CI95], 1.02 to 1.09) and exposure to the HCW wearing artificial fingernails (OR, 7.87; CI95, 1.75 to 35.36) were associated with infection or colonization with clone A. CONCLUSION: Short, well-groomed, natural nails should be mandatory for HCWs with direct patient contact

Case-Control Studies↗

PubMed2004

Emergence of resistant staphylococci on the hands of new graduate nurses.

OBJECTIVE: To describe the aerobic microbial flora on the hands of experienced and new graduate nurses over time. DESIGN: A prospective cohort design that examined the relationship between duration of employment in an intensive care unit (ICU) and the microbial flora on the hands of experienced and new graduate nurses during a 23-month period. SETTING: A 50-bed, level III-IV neonatal ICU in New York City. PARTICIPANTS: Twelve experienced nurses and 9 new graduate nurses working full time in the NICU. INTERVENTION: One hundred fifty samples were obtained from the clean, dominant hands of the nurses. Cultures were performed at baseline and then quarterly for each experienced and new graduate nurse. Baseline and final cultures of Staphylococcus epidermidis were further examined using pulsed-field gel electrophoresis. RESULTS: At baseline, a significantly larger proportion of the experienced nurses had methicillin-resistant, coagulase-negative staphylococci isolated from their hands compared with the new graduate nurses (95% and 33%, respectively; P = .0004). For a second culture, performed 1 to 4 months later, there were no longer significant differences between the two groups (82% and 54%, respectively; P = .12). By the last culture, all staphylococcal isolates were methicillin resistant in both groups of nurses; 3 were methicillin-resistant S. aureus. CONCLUSIONS: Colonization with methicillin-resistant staphylococci occurred after brief exposure to the hospital environment, despite the use of antiseptic hand hygiene agents. Furthermore, at final culture, the two groups shared one dominant hospital-acquired strain of S. epidermidis.

Cohort Studies↗

PubMed2004

Molecular epidemiology of Serratia marcescens outbreaks in two neonatal intensive care units.

OBJECTIVE: Serratia marcescens can cause serious infections in patients in neonatal intensive care units (NICUs), including sepsis, pneumonia, urinary tract infection, and conjunctivitis. We report the utility of genetic fingerprinting to identify, investigate, and control two distinct outbreaks of S. marcescens. DESIGN: An epidemiologic investigation was performed to control two clusters of S. marcescens infections and to determine possible routes of transmission. Molecular typing by pulsed-field gel electrophoresis determined the relatedness of S. marcescens strains recovered from neonates, the environment, and the hands of healthcare workers (HCWs). SETTING: Two geographically distinct level III-IV NICUs (NICU A and NICU B) in two university-affiliated teaching hospitals in New York City. RESULTS: In NICU A, one major clone, "F," was detected among isolates recovered from four neonates and the hands of one HCW. A second predominant clone, "A," was recovered from four sink drains and one rectal surveillance culture from an asymptomatic neonate. In NICU B, four neonates were infected with clone "D," and three sink drains harbored clone "H." The attributable mortality rate from bloodstream infections was 60% (3 of 5 infants). The antimicrobial susceptibilities of clone F strains varied for amikacin, cefepime, and piperacillin/tazobactam. CONCLUSIONS: S. marcescens causes significant morbidity and mortality in preterm neonates. Cross-transmission via transient hand carriage of a HCW appeared to be the probable route of transmission in NICU A. Sinks did not harbor the outbreak strains. Antimicrobial susceptibility patterns did not prove to be an accurate predictor of strain relatedness for S. marcescens.

Cross Infection↗

PubMed2004

Rapid detection of cytomegalovirus infection in transplant patients.

Human cytomegalovirus (CMV) is a well-known cause of morbidity and mortality in transplantation patients. Monitoring of CMV reactivation from latency is critical for these patients. The key to efficient and effective management of CMV infection is a test capable of rapidly monitoring and quantifying the presence of CMV in the blood. This is essential for the identification of subjects at high risk of developing CMV disease, for example, patients receiving steroid or immunosuppressive compounds for accelerated graft-versus-host disease, transplant rejection and also for the application and monitoring of pre-emptive antiviral therapeutic strategies. The assays presently available and frequently used in this setting include conventional and shell vial culture, the CMV antigenemia assay, PCR for CMV DNA, hybrid capture assay for CMV DNA and detection of CMV RNA by nucleic acid sequence-based amplification. The low sensitivity and low reproducibility of conventional cell culture and shell vial assays limit their role in the management of CMV infection to one of disease diagnosis. Diagnostic assays, such as the pp65 antigenemia and other molecular assays, have improved the ability to diagnose CMV disease quickly and accurately. These methods fulfill the requirements for a good diagnostic assay: they have high sensitivity, most can quantify viral load and they are rapid and reproducible. Their characteristics allow these assays to be used to predict the development of CMV disease and monitor response to therapy.

Antigens, Viral↗

PubMed2003

Hospital transmission of community-acquired methicillin-resistant Staphylococcus aureus among postpartum women.

Infections caused by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are being increasingly observed in patients who lack traditional risk factors. We described 8 postpartum women who developed skin and soft-tissue infections caused by MRSA at a mean time of 23 days (range, 4-73 days) after delivery. Infections included 4 cases of mastitis (3 of which progressed to breast abscess), a postoperative wound infection, cellulitis, and pustulosis. The outbreak strains were compared with the prototype CA-MRSA strain MW2 and found to be indistinguishable by pulsed-field gel electrophoresis. All were spa type 131, all contained the staphylococcal chromosomal cassette mec type IV, and all expressed Panton-Valentine leukocidin and staphylococcal enterotoxins C and H. The route of transmission was not discovered: the results of surveillance cultures of samples obtained from employees of the hospital, the hospital environment, and newborns were negative for the outbreak strain. We report that MW2, which was previously limited to the midwestern United States, has spread to the northeastern United States and has become a health care-associated pathogen.

Anti-Bacterial Agents↗

PubMed2003

The epidemiology of multidrug-resistant Acinetobacter baumannii: does the community represent a reservoir?

OBJECTIVE: To explore the role of the community as a potential reservoir for Acinetobacter baumannii. DESIGN: Antimicrobial resistance patterns and genotypes of A. baumannii isolates from patients in two Manhattan hospitals were compared with those of A. baumannii isolates from the hands of community members. RESULTS: A total of 103 isolates from two hospitals (hospital A, 81; hospital B, 22) and 23 isolates from community residents were studied. Of the hospital isolates, 36.6% were multidrug resistant (hospital A, 68.2%; hospital B, 27.8%). In contrast, there were no multidrug-resistant isolates from the community (P < .005 between hospital and community). The prevalence of A. baumannii on the hands of community residents was 10.4% (23 of 222). By molecular typing, 42 strains of A. baumannii were identified. Of the isolates from hospital A and hospital B, 55.6% (45 of 81) and 68.2% (15 of 22), respectively, were indistinguishable or closely related. In contrast, most community (83.3%) isolates were unrelated (P = .001 between hospital and community). CONCLUSION: Acinetobacter isolates from the community, characterized by a large variety of unrelated strains (83.3%), were distinct from the hospital isolates, of which 58.3% were closely related. The absence of multidrug-resistant strains in the community compared with 36.8% prevalence among hospital isolates suggests that the reservoir for epidemic strains resides in the hospital environment itself. To our knowledge, this is the first study to examine the community as a potential reservoir for hospital strains of A. baumannii.

Acinetobacter Infections↗

PubMed2003

An outbreak of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit.

OBJECTIVE: To describe the epidemiologic and molecular investigations that successfully contained an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in a neonatal intensive care unit (NICU). DESIGN: Isolates of MRSA were typed by pulsed-field gel electrophoresis (PFGE) and S. aureus protein A (spa). SETTING: A level III-IV, 45-bed NICU located in a children's hospital within a medical center. PATIENTS: Incident cases had MRSA isolated from clinical cultures (eg, blood) or surveillance cultures (ie, anterior nares). INTERVENTIONS: Infected and colonized infants were placed on contact precautions, cohorted, and treated with mupirocin. Surveillance cultures were performed for healthcare workers (HCWs). Colonized HCWs were treated with topical mupirocin and hexachlorophene showers. RESULTS: From January to March 2001, the outbreak strain of MRSA, PFGE clone B, was harbored by 13 infants. Three (1.3%) of 235 HCWs were colonized with MRSA. Two HCWs, who rotated between the adult and the pediatric facility, harbored clone C. One HCW, who exclusively worked in the children's hospital, was colonized with clone B. From January 1999 to November 2000, 22 patients hospitalized in the adult facility were infected or colonized with clone B. Spa typing and PFGE yielded concordant results. PFGE clone B was identified as spa type 16, associated with outbreaks in Brazil and Hungary. CONCLUSIONS: A possible route of MRSA transmission was elucidated by molecular typing. MRSA appears to have been transferred from our adult facility to our pediatric facility by a rotating HCW. Spa typing allowed comparison of our institution's MRSA strains with previously characterized outbreak clones.

Cross Infection↗

PubMed2002

Molecular typing strategies.

Nosocomial infections among infants in neonatal intensive care units are an increasing cause of morbidity and mortality. Efforts to rapidly detect, contain and ultimately prevent cross-transmission of these pathogens require constant vigilance by members of the epidemiology team. A vital component of an epidemiological evaluation is the ability to assess the interrelatedness of clinical isolates. This review focuses on the basic principles, strengths and weaknesses of some of the most commonly used molecular-based procedures, which determine clonal identity of outbreak strains in neonatal settings. Published evidence for the cogent selection of the method best suited for studying a particular organism and technological advances that await the new science of Molecular Epidemiology are also presented. The appropriate use of molecular typing technologies should enable reliable tracking of epidemic clones and thereby enhance the effectiveness of infection control strategies.

Bacteriophage Typing↗

PubMed2002

Nosocomial transmission of methicillin-resistant Staphylococcus aureus from a mother to her preterm quadruplet infants.

BACKGROUND: Patient-to-patient transmission of methicillin-resistant Staphylococcus aureus (MRSA) in neonatal intensive care units (NICUs) has been well described. We report the first documented outbreak of probable transmission of MRSA from a mother to 3 of her preterm quadruplet infants postnatally. METHODS: Routine surveillance of clinical microbiologic laboratory reports revealed an increased incidence of MRSA infections in our NICU, including 3 of 4 preterm quadruplets. Surveillance cultures of the anterior nares of all patients and the quadruplets' parents were performed to detect MRSA carriage. The isolates were typed by pulsed-field gel electrophoresis with the restriction endonuclease SmaI. Infection control strategies included mupirocin treatment and contact isolation precautions for infected/colonized infants. RESULTS: Clinical cultures from infants A, C, and D and surveillance cultures of the quadruplets' mother and 2 additional unrelated infants grew the same clone of MRSA. The mother's only identified risk factors for MRSA acquisition were 2 prepartum hospitalizations related to the multiple gestation and previous treatment with antibiotics. All anterior nares cultures were negative for MRSA after mupirocin treatment. CONCLUSIONS: Use of gowns and gloves by the family members of women with multiple gestations should be recommended to prevent transmission of potential pathogens in the NICU.

Adult↗

PubMed2002

Epidemiology of methicillin-susceptible Staphylococcus aureus in the neonatal intensive care unit.

OBJECTIVE: When the incidence of methicillin-susceptible Staphylococcus aureus (MSSA) infection or colonization increased in our neonatal intensive care unit (NICU), we sought to further our understanding of the relationship among colonization with MSSA, endemic infection, and clonal spread. DESIGN: A retrospective cohort study was used to determine risk factors for acquisition of a predominant clone of MSSA (clone "B"). SETTING: A 45-bed, university-affiliated, level III-IV NICU. PATIENTS: Infants hospitalized in the NICU from October 1999 to September 2000. INTERVENTIONS: Infection control strategies included surveillance cultures of infants, cohorting infected or colonized infants, contact precautions, universal glove use, mupirocin treatment of the anterior nares of all infants in the NICU, and a hexachlorophene bath for infants weighing 1,500 g or more. RESULTS: During the 1-year study period, three periods of increased incidence of MSSA colonization or infection, ranging from 6.4 to 13.5 cases per 1,000 patient-days per month, were observed. Molecular typing using pulsed-field gel electrophoresis demonstrated two predominant clones, clone "B" and clone "G," corresponding to two periods of increased incidence. Multivariate analysis demonstrated that length of stay (OR, 1.035; 95% confidence interval [CI95], 1.008 to 1.062; P = .010) increased risk per day) and the use of H2-blockers (OR, 20.44; CI95, 2.48 to 168.26; P = .005) were risk factors for either colonization or infection with clone "B," and that the use of peripheral catheters was protective (OR, 0.06; CI95, 0.01 to 0.43; P= .005). CONCLUSIONS: Control of MSSA represents unique challenges as colonization is expected, endemic infections are tolerated, and surveillance efforts generally focus on multidrug-resistant pathogens. Future studies should address cost-effective surveillance strategies for endemic infections.

Cohort Studies↗