Nosocomial fungemia in neonates associated with intravascular pressure-monitoring devices

Guideline for Prevention of Intravascular-Device–Related Infections

The “Guideline for Prevention of Intravascular Device-Related Infections” is designed to reduce the incidence of intravascular device-related infections by providing an over view of the evidence for recommendations considered prudent by consensus of Hospital Infection Control Practices Advisor y Committee (HICPAC) members. This two-part document updates and replaces the previously published Centers for Disease Control's (CDC) Guideline for Intravascular Infections (Am J Infect Control1983;11:183-199). Part I, “Intravascular Device-Related Infections: An Over view” discusses many of the issues and controversies in intravascular-device use and maintenance. These issues include definitions and diagnosis of catheter-related infection, appropriate barrier precautions during catheter insertion, inter vals for replacement of catheters, intravenous (IV) fluids and administration sets, catheter-site care, the role of specialized IV personnel, and the use of prophylactic antimi-crobials, flush solutions, and anticoagulants. Part II, “Recommendations for Prevention of Intravascular Device-Related Infections” provides consensus recommendations of the HICPAC for the prevention and control of intravascular device-related infections. A working draft of this document also was reviewed by experts in hospital infection control, internal medicine, pediatrics, and intravenous therapy. However, all recommendations contained in the guideline may not reflect the opinion of all reviewers.

Guidelines for the Prevention of Intravascular Catheter–Related Infections

Background:

Although many catheter-related blood-stream infections (CRBSIs) are preventable, measures to reduce these infections are not uniformly implemented.

Objective:

To update an existing evidenced-based guideline that promotes strategies to prevent CRBSIs.

Data Sources:

The MEDLINE database, conference proceedings, and bibliographies of review articles and book chapters were searched for relevant articles.

Studies Included:

Laboratory-based studies, controlled clinical trials, prospective interventional trials, and epidemiologic investigations.

Outcome Measures:

Reduction in CRBSI, catheter colonization, or catheter-related infection.

Synthesis:

The recommended preventive strategies with the strongest supportive evidence are education and training of healthcare providers who insert and maintain catheters; maximal sterile barrier precautions during central venous catheter insertion; use of a 2% chlorhexidine preparation for skin antisepsis; no routine replacement of central venous catheters for prevention of infection; and use of antiseptic/antibiotic-impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies (ie, education and training, maximal sterile barrier precautions, and 2% chlorhexidine for skin antisepsis).

Conclusion:

Successful implementation of these evidence-based interventions can reduce the risk for serious catheter-related infection.

Candida parapsilosis: a review of its epidemiology, pathogenesis, clinical aspects, typing and antimicrobial susceptibility

The Candida parapsilosis family has emerged as a major opportunistic and nosocomial pathogen. It causes multifaceted pathology in immuno-compromised and normal hosts, notably low birth weight neonates. Its emergence may relate to an ability to colonize the skin, proliferate in glucose-containing solutions, and adhere to plastic. When clusters appear, determination of genetic relatedness among strains and identification of a common source are important. Its virulence appears associated with a capacity to produce biofilm and production of phospholipase and aspartyl protease. Further investigations of the host-pathogen interactions are needed. This review summarizes basic science, clinical and experimental information about C. parapsilosis.

Invasive fungal infections in the ICU

Invasive fungal infections are major causes of morbidity and mortality in critically ill patients. Foremost among these is invasive candidiasis. In recent years, invasive aspergillosis (IA) and zygomycosis have emerged as major problems in susceptible, critically ill patients. Risk factors for invasive fungal infections, including disrupted anatomic barriers, suppressed antifungal host responses, and exposure to potentially opportunistic fungi are common in critically ill patients. The expanded antifungal armamentarium and advent of rapid diagnostic techniques are altering the approach to invasive fungal infections in the intensive care unit (ICU). Herein, we review recent developments in the field of antifungal host defenses, the changing epidemiology of fungal infections in the ICU, the pharmacology of antifungal agents of importance to critically ill patients, and the evolving approaches to therapy in this setting.

Candida parapsilosis, an emerging fungal pathogen

SUMMARY

Candida parapsilosis is an emerging major human pathogen that has dramatically increased in significance and prevalence over the past 2 decades, such that C. parapsilosis is now one of the leading causes of invasive candidal disease. Individuals at the highest risk for severe infection include neonates and patients in intensive care units. C. parapsilosis infections are especially associated with hyperalimentation solutions, prosthetic devices, and indwelling catheters, as well as the nosocomial spread of disease through the hands of health care workers. Factors involved in disease pathogenesis include the secretion of hydrolytic enzymes, adhesion to prosthetics, and biofilm formation. New molecular genetic tools are providing additional and much-needed information regarding C. parapsilosis virulence. The emerging information will provide a deeper understanding of C. parapsilosis pathogenesis and facilitate the development of new therapeutic approaches for treating C. parapsilosis infections.

Candida parapsilosis fungemia in neonates: genotyping results suggest healthcare workers hands as source, and review of published studies

An outbreak of Candida parapsilosis fungemia involving 17 neonatal intensive care unit (NICU) patients was studied. There were 14 blood culture and nine colonizing isolates from other sites available. The hands of NICU healthcare workers (HCW) yielded eight isolates. Screening of the isolates by random amplified polymorphic DNA (RAPD) method showed only three profiles. Typing by restriction fragment length polymorphism (RFLP) revealed all blood isolates were RFLP subtype VII-1. Among the nine infant colonizing isolates, there were four different RFLP subtypes; four of the isolates were subtype VII-1. Seven of the eight isolates from HCW were RFLP subtype VII-1. The majority of infant colonizers were not found in the blood, suggesting a possible direct spread of the epidemic subtype VII-1 strain from HCW hands to infant blood. The source of the infant colonizing strains is unclear, but non-VII-1 strains may be largely of maternal origin and VII-1 strains from HCW. These findings reinforce prior studies that have implicated HCW hands as the source of nosocomial, including neonatal, fungemia.

Oral nystatin prophylaxis to prevent invasive candidiasis in Neonatal Intensive Care Unit

The use of oral nystatin to prevent fungal colonisation and infection in neonates in the Neonatal Intensive Care Unit (NICU) is still an open question and not yet recommended as a standard of care. To determine whether prophylactic oral nystatin results in a decreased incidence of invasive candidiasis in the newborn infants, a total of 3991 infants were divided randomly into two groups. Group A infants (n = 1995), only those neonates who were identified as yeast carriers (oral moniliasis) were treated with oral nystatin. Group B infants, all neonates who were admitted to the unit received oral nystatin, was routinely administered three times a day. Group A was divided into groups A1 and A2 (who were treated only if identified as yeast carriers). Urine and rectal cultures were taken on admission and then weekly thereafter. There were 215 (14.2%), 27 (5.6%) and 36 (1.8%) patients positive for invasive candidiasis in groups A1, A2 and B respectively. Oral nystatin prophylaxis significantly reduced the invasive candidiasis (P = 0.004) in extremely low-birth weight (ELBW) and very low-birth weight (VLBW) infants. Prophylactic administration of oral nystatine to the ELBW and VLBW infants results in a decreased risk of invasive candidiasis.

Epidemiologic and molecular characterization of an outbreak of Candida parapsilosis bloodstream infections in a community hospital

Candida parapsilosis is an important cause of bloodstream infections in the health care setting. We investigated a large C. parapsilosis outbreak occurring in a community hospital and conducted a case-control study to determine the risk factors for infection. We identified 22 cases of bloodstream infection with C. parapsilosis: 15 confirmed and 7 possible. The factors associated with an increased risk of infection included hospitalization in the intensive care unit (adjusted odds ratio, 16.4; 95% confidence interval, 1.8 to 148.1) and receipt of total parenteral nutrition (adjusted odds ratio, 9.2; 95% confidence interval, 0.9 to 98.1). Samples for surveillance cultures were obtained from health care worker hands, central venous catheter insertion sites, and medical devices. Twenty-six percent of the health care workers surveyed demonstrated hand colonization with C. parapsilosis, and one hand isolate was highly related to all case-patient isolates by tests with the DNA probe Cp3-13. Outbreak strain isolates also demonstrated reduced susceptibilities to fluconazole and voriconazole. This largest known reported outbreak of C. parapsilosis bloodstream infections in adults resulted from an interplay of host, environment, and pathogen factors. Recommendations for control measures focused on improving hand hygiene compliance.

Invasive neonatal candidiasis: an overview

Until the 1980s, recovery of Candida species from normally sterile body sites in high-risk infants was often dismissed as contamination. Such delay in diagnosis often resulted in death, multifocal disease, or significant morbidity, outcomes that still occur today. Problems establishing the diagnosis of invasive candidiasis persist, while the frequency of this infection in increasingly fragile and smaller premature infants appears to be increasing. Standard culture techniques have limited sensitivity and often take several days for recovery of Candida when positive. Heightened suspicion and improved diagnostic tools are needed. Less toxic antifungal agents with better tissue penetration profiles will help. Better understanding of risk factors and pathogenesis may permit more effective strategies for prophylaxis and appropriately targeted empiric antifungal therapy.

Colonization and epithelial adhesion in the pathogenesis of neonatal candidiasis

Candida species are important nosocomial pathogens in the newborn population, particularly among the premature very-low-birth-weight infants in neonatal intensive care units. Candida colonization of the neonatal skin and gastrointestinal tract is an important first step in the pathogenesis of invasive disease. C albicans is the most commonly isolated species in colonized or infected infants. Over the past decade the incidence of both colonization and infection with other Candida species, particularly C parapsilosis, has risen dramatically. Colonization of the infant occurs early in life and is affected by a variety of common practices in neonatal intensive care. Microbial factors also augment colonization, including the ability of Candida to adhere to human epithelium. A better understanding of the complex interactions between host risk factors and virulence traits of colonizing yeast may allow the risk of systemic spread to be reduced in the population of premature infants.

Guidelines for the prevention of intravascular catheter-related infections

BACKGROUND

Although many catheter-related bloodstream infections (CRBSIs) are preventable, measures to reduce these infections are not uniformly implemented.

OBJECTIVE

To update an existing evidenced-based guideline that promotes strategies to prevent CRBSIs.

DATA SOURCES

The MEDLINE database, conference proceedings, and bibliographies of review articles and book chapters were searched for relevant articles.

STUDIES INCLUDED

Laboratory-based studies, controlled clinical trials, prospective interventional trials, and epidemiologic investigations.

OUTCOME MEASURES

Reduction in CRBSI, catheter colonization, or catheter-related infection.

SYNTHESIS

The recommended preventive strategies with the strongest supportive evidence are education and training of healthcare providers who insert and maintain catheters; maximal sterile barrier precautions during central venous catheter insertion; use of a 2% chlorhexidine preparation for skin antisepsis; no routine replacement of central venous catheters for prevention of infection; and use of antiseptic/antibiotic-impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies (ie, education and training, maximal sterile barrier precautions, and 2% chlorhexidine for skin antisepsis).

CONCLUSION

Successful implementation of these evidence-based interventions can reduce the risk for serious catheter-related infection.

Guidelines for the Prevention of Intravascular Catheter–Related Infections

These guidelines have been developed for practitioners who insert catheters and for persons responsible for surveillance and control of infections in hospital, outpatient, and home health-care settings. This report was prepared by a working group comprising members from professional organizations representing the disciplines of critical care medicine, infectious diseases, health-care infection control, surgery, anesthesiology, interventional radiology, pulmonary medicine, pediatric medicine, and nursing. The working group was led by the Society of Critical Care Medicine (SCCM), in collaboration with the Infectious Disease Society of America (IDSA), Society for Healthcare Epidemiology of America (SHEA), Surgical Infection Society (SIS), American College of Chest Physicians (ACCP), American Thoracic Society (ATS), American Society of Critical Care Anesthesiologists (ASCCA), Association for Professionals in Infection Control and Epidemiology (APIC), Infusion Nurses Society (INS), Oncology Nursing Society (ONS), Society of Cardiovascular and Interventional Radiology (SCVIR), American Academy of Pediatrics (AAP), and the Healthcare Infection Control Practices Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention (CDC) and is intended to replace the Guideline for Prevention of Intravascular Device–Related Infections published in 1996. These guidelines are intended to provide evidence-based recommendations for preventing catheter-related infections. Major areas of emphasis include 1) educating and training health-care providers who insert and maintain catheters; 2) using maximal sterile barrier precautions during central venous catheter insertion; 3) using a 2% chlorhexidine preparation for skin antisepsis; 4) avoiding routine replacement of central venous catheters as a strategy to prevent infection; and 5) using antiseptic/antibiotic impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies (i.e., education and training, maximal sterile barrier precautions, and 2% chlorhexidine for skin antisepsis). These guidelines also identify performance indicators that can be used locally by health-care institutions or organizations to monitor their success in implementing these evidence-based recommendations.

Guidelines for the prevention of intravascular catheter-related infections

BACKGROUND

Although many catheter-related bloodstream infections (CR-BSIs) are preventable, measures to reduce these infections are not uniformly implemented.

OBJECTIVE

To update an existing evidenced-based guideline that promotes strategies to prevent CR-BSIs.

DATA SOURCES

The MEDLINE database, conference proceedings, and bibliographies of review articles and book chapters were searched for relevant articles.Studies Included: Laboratory-based studies, controlled clinical trials, prospective interventional trials, and epidemiological investigations.

OUTCOME MEASURES

Reduction in CR-BSI, catheter colonization, or catheter-related infection.

SYNTHESIS

The recommended preventive strategies with the strongest supportive evidence are education and training of healthcare providers who insert and maintain catheters; maximal sterile barrier precautions during central venous catheter insertion; use of a 2% chlorhexidine preparation for skin antisepsis; no routine replacement of central venous catheters for prevention of infection; and use of antiseptic/antibiotic impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies (i.e. education and training, maximal sterile barrier precautions and 2% chlorhexidine for skin antisepsis).

CONCLUSION

Successful implementation of these evidence-based interventions can reduce the risk for serious catheter-related infection.

Guidelines for the prevention of intravascular catheter-related infections. The Hospital Infection Control Practices Advisory Committee, Center for Disease Control and Prevention, U.S

These guidelines have been developed for practitioners who insert catheters and for persons responsible for surveillance and control of infections in hospital, outpatient, and home health-care settings. This report was prepared by a working group comprising members from professional organizations representing the disciplines of critical care medicine, infectious diseases, health-care infection control, surgery, anesthesiology, interventional radiology, pulmonary medicine, pediatric medicine, and nursing. The working group was led by the Society of Critical Care Medicine (SCCM), in collaboration with the Infectious Disease Society of America (IDSA), Society for Healthcare Epidemiology of America (SHEA), Surgical Infection Society (SIS), American College of Chest Physicians (ACCP), American Thoracic Society (ATS), American Society of Critical Care Anesthesiologists (ASCCA), Association for Professionals in Infection Control and Epidemiology (APIC), Infusion Nurses Society (INS), Oncology Nursing Society (ONS), Society of Cardiovascular and Interventional Radiology (SCVIR), American Academy of Pediatrics (AAP), and the Healthcare Infection Control Practices Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention (CDC) and is intended to replace the Guideline for Prevention of Intravascular Device-Related Infections published in 1996. These guidelines are intended to provide evidence-based recommendations for preventing catheter-related infections. Major areas of emphasis include 1) educating and training health-care providers who insert and maintain catheters; 2) using maximal sterile barrier precautions during central venous catheter insertion; 3) using a 2% chlorhexidine preparation for skin antisepsis; 4) avoiding routine replacement of central venous catheters as a strategy to prevent infection; and 5) using antiseptic/antibiotic impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies (ie, education and training, maximal sterile barrier precautions, and 2% chlorhexidine for skin antisepsis). These guidelines also identify performance indicators that can be used locally by health-care institutions or organizations to monitor their success in implementing these evidence-based recommendations.

Non-albicans Candida spp. causing fungaemia: pathogenicity and antifungal resistance

Non-albicans Candida (NAC) species cause 35-65% of all candidaemias in the general patient population. They occur more frequently in cancer patients, mainly in those with haematological malignancies and bone marrow transplant (BMT) recipients (40-70%), but are less common among intensive care unit (ITU) and surgical patients (35-55%), children (1-35%) or HIV-positive patients (0-33%). The proportion of NAC species among Candida species is increasing: over the two decades to 1990, NAC represented 10-40% of all candidaemias. In contrast, in 1991-1998, they represented 35-65% of all candidaemias. The most common NAC species are C. parapsilosis (20-40% of all Candida species), C. tropicalis (10-30%), C. krusei (10-35%) and C. glabrata (5-40%). Although these four are the most common, at least two other species are emerging: C. lusitaniae causing 2-8% of infections, and C. guilliermondii causing 1-5%. Other NAC species, such as C. rugosa, C. kefyr, C. stellatoidea, C. norvegensis and C. famata are rare, accounting for less than 1% of fungaemias in man. In terms of virulence and pathogenicity, some NAC species appear to be of lower virulence in animal models, yet behave with equal or greater virulence in man, when comparison is made with C. albicans. Mortality due to NAC species is similar to C. albicans, ranging from 15% to 35%. However, there are differences in both overall and attributable mortality among species: the lowest mortality is associated with C. parapsilosis, the highest with C. tropicalis and C. glabrata (40-70%). Other NAC species including C. krusei are associated with similar overall mortality to C. albicans (20-40%). Mortality in NAC species appears to be highest in ITU and surgical patients, and somewhat lower in cancer patients, children and HIV-positive patients. There is no difference between overall and attributable mortality, with the exception of C. glabrata which tends to infect immunocompromised individuals. While the crude mortality is low, attributable mortality (fungaemia-associated mortality) is higher than with C. albicans. There are several specific risk factors for particular NAC species: C. parapsilosis is related to foreign body insertion, neonates and hyperalimentation; C. krusei to azole prophylaxis and along with C. tropicalis to neutropenia and BMT; C. glabrata to azole prophylaxis, surgery and urinary or vascular catheters; C. lusitaniae and C. guilliermondii to previous polyene (amphotericin B or nystatin) use; and C. rugosa to burns. Antifungal susceptibility varies significantly in contrast to C. albicans: some NAC species are inherently or secondarily resistant to fluconazole; for example, 75% of C. krusei isolates, 35% of C. glabrata, 10-25% of C. tropicalis and C. lusitaniae. Amphotericin B resistance is also seen in a small proportion: 5-20% of C. lusitaniae and C. rugosa, 10-15% of C. krusei and 5-10% of C. guilliermondii. Other NAC species are akin to C. albicans-susceptible to both azoles and polyenes (C. parapsilosis, the majority of C. guilliermondii strains and C. tropicalis). Therefore, 'species directed' therapy should be administered for fungaemia according to the species identified-amphotericin B for C. krusei and C. glabrata, fluconazole for other species, including polyene-resistant or tolerant Candida species (C. lusitaniae, C. guilliermondii). In vitro susceptibility testing should be performed for most species of NAC in addition to removal of any foreign body to optimize management.

Risk factors for nosocomial candidaemia: a case-control study in children

Candida spp. are increasingly important nosocomial pathogens in critically ill children. Data on risk factors of acquisition in children with candidaemia are limited. To determine the incidence, prognosis and risk factors for acquisition of nosocomial candidaemia in children, a prospective case-control study was performed between July 1998 and January 2000. Candidaemia was defined as the presence of at least one positive blood culture containing Candida spp. For each case, two controls were selected and matched for time and site of hospital admission. Logistic regression was used to obtain estimates of risk after simultaneous control for other variables. Candidaemia was diagnosed in 24 children (1.09/1000 admissions). The species most frequently isolated were Candida albicans (50%) and Candida parapsilosis (17%). Mean age was 58.2+/-58 months between cases and 41.8+/-52.2 months in controls (P not significant). The strongest risk factors for acquisition found in the univariate analysis were underlying disease, previous antibiotic treatment, the number of antibiotics administered, presence of a long-duration catheter and total parenteral nutrition (P<0.05). Sex, the site of hospital admission, artificial ventilatory assistance, transitory venous catheters, arterial and peripherally venous accesses, bladder catheter and transfusions were not statistically significant. The risk factors identified by multiple logistic regression analysis were: permanent catheter (OR 31.5; 3.19-310) and total parenteral nutrition (OR 10.5; 2.76-40.0). Nine (37%) children with nosocomial candidaemia and seven (15%) controls died (P=0.05). These findings should facilitate development of rational approaches to preventing infection and assist clinicians in identifying those patients in whom this life-threatening complication is likely to occur.

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.

Survival of some medically important fungi on hospital fabrics and plastics

Tests of the survival of Candida spp., Aspergillus spp., a Fusarium sp., a Mucor sp., and a Paecilomyces sp. on hospital fabrics and plastics indicated that viability was variable, with most fungi surviving at least 1 day but many living for weeks. These findings reinforce the need for appropriate disinfection and conscientious contact control precautions.

Review of 49 neonates with acquired fungal sepsis: further characterization

BACKGROUND

Neonatal acquired fungal sepsis (AFS) is a risky condition that warrants every effort for early diagnosis and management.

METHODS

We retrospectively reviewed the medical charts of all 4445 neonatal intensive care unit (NICU) admissions in the past 10 years and detected 49 neonates with AFS. We then compared their data with those of 49 matched control neonates who did not have AFS. The following details were collected: gestational, perinatal and neonatal courses; bacterial sepsis; antibacterial therapy; laboratory and imaging investigations; and antifungal therapy and its complications.

RESULTS

The incidence of AFS was.4 to 2 cases per 1000 live-births and 3.8% to 12.9% of very low birth weight (VLBW) infants. Compared with 1989 through 1992, between 1993 and 1995 the rate of AFS in VLBW neonates significantly increased (3. 8%-5.6% --> 9.6%-12.9%), along with a significant increase of NICU admission rate (369-410 --> 496-510 admissions/year). Compared with controls, AFS neonates had significantly longer hospitalizations, higher rates of mechanical ventilation, umbilical vein catheterization, and previous treatment with broad-spectrum antibacterial agents (amikacin, vancomycin, ceftazidime, or imipenem). At the onset of AFS, 42.8% of patients had hyperthermia and 40.9% had normal white blood cell count. Causative fungi were as follows: Candida albicans-42.8% of cases, Candida parapsilosis-26.5%, and Candida tropicalis-20.4%. Fungal dissemination was rare, complications of antifungal therapy were infrequent, and no deaths occurred.

CONCLUSIONS

First, non-albicans Candida have become more frequent in neonatal AFS. Second, mechanical ventilation and antibacterial agents are significant risk factors for AFS. Third, hyperthermia is a frequent presenting sign of AFS. Fourth, a normal white blood cell count does not rule out AFS. Fifth, meningeal involvement in neonatal AFS should be ruled out before initiation of antifungal therapy. Sixth, the policy of empiric antifungal therapy for AFS should be considered on an individual NICU basis.newborn infant, fungal sepsis, clinical signs, risk factors.

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.

Outbreak of Candida albicans fungaemia in a neonatal intensive care unit

During a 4-month period, 9 premature infants hospitalized in a neonatal intensive care unit (NICU) developed Candida albicans fungaemia. All 9 infants received antifungal agents. Fluconazole was administered in 7 patients and successfully eradicated this organism in 6 with no adverse effects. For epidemiological investigation, 64 environmental specimens and hand-washings of all 54 staff members involved in the NICU were examined for the presence of this organism. No C. albicans could be identified from environmental sources, while the hand-washing of 1 nurse was C. albicans-positive. Two genotyping methods, including electrophoretic karyotyping using contour-clamped homogeneous electric field gel electrophoresis and polymerase chain reaction-based direct sequencing of rRNA gene, were used in the analysis of the isolates recovered from blood cultures of the infants, the hand-washing of the nurse and 7 control isolates. Both methods yielded comparable results and revealed that all 13 isolates from infected infants as well as the isolate from hand washing of the nurse were of the same genotype while the control isolates were distinct. These results suggest that the outbreak of C. albicans fungaemia was caused by a particular strain and possibly via cross-infection. In addition, we showed that fluconazole seemed to be safe and effective in treating C. albicans fungaemia in neonates, although the data were limited.

Clustering of Candida infections in the neonatal intensive care unit: concurrent emergence of multiple strains simulating intermittent outbreaks

BACKGROUND

Clusters of Candida albicans and Candida parapsilosis infections were noted intermittently in our neonatal intensive care unit (NICU). We attempted to determine whether these clusters represented single strain outbreaks or coincidental emergence of unrelated strains.

METHODS

A retrospective examination of the frequency of candidemia during a 9-year period, two point prevalence studies of colonization and assessment of strain relatedness of individual infant isolates during and in between clusters during a 2-year period with karyotyping and restriction endonuclease analysis of genomic DNA (REAG).

RESULTS

C. albicans and C. parapsilosis infections emerged in a scattered pattern (1 to 2 cases every few months) with intermittent clustering of 3 cases/month. The colonization rate was 50% 5 weeks after an apparent cluster, equally distributed between C. albicans and C. parapsilosis, and 17.6% (exclusively with C. parapsilosis) 4 months after absence of invasive disease. Utilizing REAG or karyotyping singly we noted 12 and 16 DNA banding patterns, respectively, among 23 infant isolates. Few patterns were observed repeatedly over 2- to 20-month periods, implying recurrent emergence of the same strains. Combining karyotyping with REAG revealed a different epidemiologic pattern. It identified 20 distinct composites with identical composites in 3 infant pairs. All infants with identical composites were in the NICU concurrently. The frequency of strain relatedness was comparable among clustered cases (16.7%), scattered cases (7.7%) and simultaneously colonized infants (16.7%).

CONCLUSIONS

These findings illustrate that Candida infections clustered periodically in our NICU but that these clusters were often caused by unrelated strains with infrequent cross-infection during and between clusters. With suboptimal typing this pattern of emergence can be mistaken for same strain outbreaks.

Molecular tracking of Candida albicans in a neonatal intensive care unit: long-term colonizations versus catheter-related infections

Nosocomial neonatal candidiasis is a major problem in infants requiring intensive therapy. The subjects of this retrospective study were nine preterm infants admitted to the neonatal intensive care unit of the Hospital Central de Asturias between March 1993 and August 1994. The infants were infected with or colonized by Candida albicans. Five patients developed C. albicans bloodstream infections. A total of 36 isolates (including isolates from catheters and parenteral nutrition) were examined for molecular relatedness by PCR fingerprinting and restriction fragment length polymorphism (RFLP) analysis. The core sequence of phage M13 was used as a single primer in the PCR-based fingerprinting procedure, and RFLP analysis was performed with C. albicans-specific DNA probe 27A. Both techniques were evaluated with a panel of eight C. albicans reference strains, and each technique showed eight different patterns. With the 36 isolates from neonates, each technique enabled us to identify by PCR and RFLP analysis seven and six different patterns, respectively. The combination of these two methods (composite DNA type) identified eight different profiles. A strain with one of these profiles was present in three patients and in their respective catheters. Patients infected with or colonized by this isolate profile were clustered in time. Among the other patients, each patient was infected over time and at multiple anatomic sites with a C. albicans strain with a distinct DNA type. We conclude that C. albicans was most commonly producing long-term colonizations, although horizontal transmission probably due to catheters also occurred.

Nosocomial Candida. Epidemiology, transmission, and prevention

The NNIS and the newly established SCOPE data indicate that the relative proportion of organisms causing nosocomial bloodstream infections has changed over the last decade, with Candida species now being firmly established as one of the most frequent agents. The epidemiology of nosocomial candidemia is continually being refined, but established predisposing factors including immunosuppression and malignancies, use of broad spectrum antibiotics, and use of indwelling central catheters remain as significant risk factors. The high cost of health care and greater attention to continuous quality improvement will stimulate better and more effective ways of diagnosing and treating candida infections using combined clinical and microbiologic acumen. There is room for optimism as newer antifungal agents with reduced toxicities have impact on therapy of candidal infections. Aggressive development of still more agents and reformulations of older agents continue in earnest. Even greater consolation comes from the increased awareness of lay and medical personnel alike regarding the appropriate and judicious use of antimicrobial agents.

Candida parapsilosis bloodstream infections in neonatal intensive care unit patients: epidemiologic and laboratory confirmation of a common source outbreak

BACKGROUND

Candida parapsilosis is a common cause of sporadic and epidemic infections in neonatal intensive care units (NICUs). When a cluster of C. parapsilosis bloodstream infections occurred in NICU patients in a hospital in Louisiana, it provided us with the opportunity to conduct an epidemiologic investigation and to apply newly developed molecular typing techniques.

METHODS

A case-patient was defined as any NICU patient at Louisiana State University Medical Center, University Hospital, with a blood culture positive for C. parapsilosis during July 20 to 27, 1991. To identify risk factors for C. parapsilosis bloodstream infection, a cohort study of all NICU infants admitted during July 17 to 27, 1991, was performed. Electrophoretic karyotyping was used to assess the relatedness of C. parapsilosis isolates.

RESULTS

The receipt of liquid glycerin given as a suppository was identified as a risk factor (relative risk, 31.2; 95% confidence intervals, 4.3 to 226.8). Glycerin was supplied to the NICU in a 16-oz multidose bottle. Bottles used at the time of the outbreak were not available for culture. All six available isolates from four case-patients had identical chromosomal banding patterns; six University Hospital non-outbreak isolates had different banding patterns.

CONCLUSIONS

This study demonstrates the utility of combined epidemiologic and laboratory techniques in identifying a novel common source for a C. parapsilosis bloodstream infection outbreak and illustrates that extreme caution should be exercised when using multidose medications in more than one patient.

Epidemiology of nosocomial fungal infections

This paper briefly reviews the current knowledge of the epidemiology and modes of transmission of nosocomial fungal infections and some of the therapeutic options for treating these diseases. In the mid-1980s, many institutions reported that fungi were common pathogens in nosocomial infections. Most, if not all, hospitals care for patients at risk for nosocomial fungal infections. The proportion in all nosocomial infections reportedly caused by Candida spp. increased from 2% in 1980 to 5% in 1986 to 1989. Numerous studies have identified common risk factors for acquiring these infections, most of which are very common among hospitalized patients; some factors act primarily by inducing immunosuppression (e.g., corticosteroids, chemotherapy, malnutrition, malignancy, and neutropenia), while others primarily provide a route of infection (e.g., extensive burns, indwelling catheter), and some act in combination. Non-albicans Candida spp., including fluconazole-resistant C. krusei and Torulopsis (C.) glabrata, have become more common pathogens. Newer molecular typing techniques can assist in the determination of a common source of infection caused by several fungal pathogens. Continued epidemiologic and laboratory research is needed to better characterize these pathogens and allow for improved diagnostic and therapeutic strategies.

Genotypic analysis of pseudoepidemic due to contamination of Hanks' balanced salt solution with Candida parapsilosis

A cluster of isolates of Candida parapsilosis recovered from clinical specimens was demonstrated, by both classical and molecular epidemiological techniques, to have resulted from contamination in the laboratory. The source of the pseudoepidemic was a repeatedly utilized contaminated container of Hanks' balanced salt solution used in specimen processing. The patterns of restriction fragment length polymorphisms of DNA extracted from the clinical and environmental isolates were identical to each other but composed a newly identified unique C. parapsilosis DNA type.

Risk factors of infection and digestive tract colonization by Candida spp. in a neonatal intensive care unit

In this study we determined the risk factors for infection and colonization by Candida spp. in our Neonatal Intensive Care Unit (NICU). We designed a cohort study in the NICU of the La Paz University Hospital. Over a one year period, 153 neonates admitted to the NICU were studied. In the bivariable analysis, hospitalization period, central catheterization, parenteral feeding, parenteral lipid feeding, respiratory support and premature rupture of the membranes (PRM) were statistically associated with infection and colonization; age was only associated with infection. Logistic regression was used to control the confusing factors. The hospitalization period was a risk factor for infection and colonization. PRMs were also colonization risk factors. We developed a statistical equation that predicts the probability of infection or colonization by Candida spp. that are related to a neonate's specific characteristics. The equation helps us to develop preventive procedures.

Investigation of Candida albicans transmission in a surgical intensive care unit cluster by using genomic DNA typing methods

An apparent outbreak of serious Candida albicans infections (n = 6) occurred in a surgical intensive care unit over a 4-week period. Four patients developed C. albicans bloodstream infections. An additional patient developed catheter-related C. albicans infection; the sixth patient developed an infection of cerebrospinal fluid. C. albicans was isolated from the hands of five health care workers (17%) and the throat of one health care worker (3%) during the outbreak investigation. Karyotyping and restriction endonuclease analysis of genomic DNA with BssHII of 23 C. albicans isolates from patients and the 6 health care worker isolates revealed 9 and 12 different patterns, respectively. Three of six patients appeared to be infected with the same C. albicans strain (two bloodstream infections and one cerebrospinal fluid infection). The hands of a health care worker were colonized with strain that appeared identical to an isolate from a patient prior to infection of the patient. However, restriction endonuclease analysis with SfiI found differences among the isolates determined to be identical by the other two methods. Karyotyping alone does not appear to be sufficient to differentiate between outbreak and control isolates. Restriction endonuclease analysis typing may be a more sensitive method than karyotyping alone in the investigation of a cluster of C. albicans infections. Furthermore, the use of more than one restriction enzyme may be necessary for optimal strain discrimination in restriction endonuclease analysis of genomic DNA.

Trends and sources of nosocomial fungaemia

Concurrent surveillance of blood culture isolates in a 1000-bed tertiary care hospital over a 7-year period from 1986 to 1993 identified 102 episodes of nosocomial fungaemia, representing 6.6% of all episodes of nosocomial bloodstream infections and 0.49/1000 admissions. No significant change in the frequency, rate, source or microbial aetiology of nosocomial fungaemia occurred over the 7-year period. Candida albicans accounted for 74%, followed by Candida (Torulopsis) glabrata (8%), C. parapsilosis (7%), C. tropicalis (3%), C. lusitaniae (2%), C. krusei, Malassezia furfur Saccharomyces cerevisiae, Hansenula anomala and Cryptococcus albidus (one each). 'Primary' fungaemia, usually attributed to intravascular catheters, was considered to be the source in 65% of cases, with 64% of these patients receiving total parenteral nutrition (TPN). Other important sources of infection included the urinary tract (11%), the gastrointestinal tract (8%) and the respiratory tract (7%). Sixty-four % of patients were in one of the hospital's seven intensive care units (ICUs) when their infection developed, the neonatal ICU and adult medical/surgical ICU each accounting for 21%. Only 7% of cases were associated with neutropenia and another 14% with malignancy or immunosuppression. Death occurred within 7 days of diagnosis of fungaemia in 23 cases. In eight instances, fungaemia was considered the main cause of death. We conclude that in our hospital nosocomial fungaemia is largely caused by C. albicans, occurring in association with intravascular catheter use and TPN in ICU patients. Most cases are not associated with recognized immune defence defects. Fungaemia is associated with a high short-term mortality rate.

Selective decontamination with nystatin for control of a Candida outbreak in a neonatal intensive care unit

Selective decontamination of the digestive tract (SDD) with oral nystatin was evaluated as a measure to control an outbreak of Candida infection in a neonatal intensive care unit (NICU). Seventy-six out of 106 neonates who carried Candida spp. received the main study manoeuvre (the application of oral nystatin in the throat and stomach) during the 12-month open trial. One third of the neonates weighed < 1500 g whilst about half were being ventilated. The mean stay was 33.2 d (SD +/- 46.9). Two cases with candidaemia within a fortnight were associated with a yeast carriage rate in the NICU of about 50%; more than 80% of the isolates were Candida parapsilosis. During the implementation period there were four new neonates with fungaemia caused by C. parapsilosis. Once the carriage rate dropped below 5% (P < 0.001), no new cases of systemic infection with the outbreak strain were recognized in the following 8 months. It took 3.5 months to control the outbreak. The observation that all other clinical diagnostic samples were free from Candida suggests that translocation from throat or gut into the systemic circulation occurred. SDD with oral nystatin was effective in reducing the yeast carriage index (mean index 1.93, before SDD; 0.45, after SDD; P < 0.001). A significant reduction of carriage, both in rates and indices, is thought to have contributed to the control of this candida outbreak.

Outbreak of Candida bloodstream infections associated with retrograde medication administration in a neonatal intensive care unit

An outbreak of candidemia involving five infants receiving total parenteral nutrition in the neonatal intensive care unit was investigated. Cultures of the intravenous fluids demonstrated that the retrograde medication syringe fluids were significantly more likely to be contaminated with Candida than were other fluids being administered to the infants (p less than 0.001). Candidemia was significantly associated with total parenteral nutrition (p = 0.04) and retrograde medication administration (p = 0.02). A survey of nursing practice found that reuse of the retrograde syringes was the most likely cause of contamination. Molecular typing showed that the strains of Candida albicans that were isolated from the bloodstream were also found in the retrograde syringes and that at least three strains of C. albicans and one strain each of Candida tropicalis and Candida parapsilosis were involved. In vitro growth curves demonstrated that Candida species had a selective growth advantage versus bacteria in the total parenteral nutrition fluid. An in vitro simulation of the retrograde medication administration system suggested that the outbreak probably developed after the frequency of changing intravenous tubing was decreased from every 24 hours to every 72 hours. The outbreak was terminated by using syringes only once and resuming intravenous tubing changes every 24 hours. Retrograde medication administration in association with total parenteral nutrition may increase the risk of Candida line infection.

Laboratory diagnosis of invasive candidiasis

Severe infections due to Candida species have become more frequent during the past two decades because of the increasing numbers of immunosuppressed patients being treated in our hospitals. Distinguishing colonization from invasive disease requires knowledge of the pathogenetic mechanisms leading to invasion. To assist the clinician in therapeutic decisions, clinical microbiologists should identify to species Candida organisms isolated from immunosuppressed patients. Quantitative or semiquantitative cultures of urine, burn tissues, intravascular catheter tips, and bronchoalveolar lavage specimens may provide useful information. Immunofluorescent staining of certain specimens can enhance diagnostic yield. The lysis-centrifugation blood culture technique offers some advantages over traditional broth techniques in detecting Candida fungemia. Antibody testing is of limited diagnostic value in highly immunosuppressed patients. Developing simple and reliable tests for detecting antigens or metabolites of Candida spp. in the sera of infected patients has proven difficult. Methods for typing Candida albicans are evolving. Typing should prove useful for studying the epidemiology of candidiasis in hospitalized patients.

Risk factors for nosocomial candidemia: a case-control study in adults without leukemia

PURPOSE

The purpose of this study was to define risk factors for nosocomial candidemia in adult patients without leukemia at a tertiary care medical center.

PATIENTS AND METHODS

All patients with nosocomial candidemia between August 1, 1981, and October 31, 1984, were included if they met strict selection criteria and did not have acute or chronic leukemia. For each case, one control was selected from among patients admitted during the same month/year and matched for hospital service and duration of hospitalization up to the first blood culture that grew Candida species. Logistic regression was used to obtain estimates of risk after simultaneously controlling for other variables.

RESULTS

Candida albicans caused 24 of the 48 fungemias studied. The risk factors identified included the presence of a central line (odds ratio, 26.4; 95% confidence interval, 1.5 to 451.1); bladder catheter (13.0 1.3 to 131.4); two or more antibiotics (25.1, 2.1 to 318); azotemia (22.1, 2.2 to 223.2); transfer from another hospital (21.3, 1.7 to 274.5); diarrhea (10.2, 1.03 to 101.4); and candiduria (27.0, 1.7 to 423.5). A prior surgical procedure was associated with lowered risk (0.1, 0.01 to 0.9), suggesting perhaps that medical service patients are at higher risk than those on surgical services. Because total parenteral nutrition was always administered by means of a central line, it could not be shown to increase the risk over that conferred by a central line alone.

CONCLUSIONS

This study has defined seven major risk factors for nosocomial candidemia. These findings should facilitate development of rational approaches to preventing infection and may assist clinicians in identifying those patients in whom this life-threatening complication is likely to occur.