Prevention and treatment of Candida infections in neonates

Development of a multiplex PCR short tandem repeat typing scheme for Candida krusei

Candida krusei is a human pathogenic yeast that can cause candidemia with the lowest 90-day survival rate in comparison to other Candida species. Infections occur frequently in immunocompromised patients and several C. krusei outbreaks in health care facilities have been described. Here, we developed a short tandem repeat (STR) typing scheme for C. krusei to allow for fast and cost-effective genotyping of an outbreak and compared identified relatedness of ten isolates to SNP calling from whole-genome sequencing (WGS). From a selection of 14 novel STR markers, six were used to develop two multiplex PCRs. Additionally, three previously reported markers were selected for a third multiplex PCR. In total, 119 C. krusei isolates were typed using these nine markers and 79 different genotypes were found. STR typing correlated well with WGS SNP typing, as isolates with the same STR genotype varied by 8 and 19 SNPs, while isolates that differed in all STR markers varied at least tens of thousands of SNPs. The STR typing assay was found to be specific for C. krusei, stable in 100 subcloned generations, and comparable to SNP calling by WGS. In summary, this newly developed C. krusei STR typing scheme is a fast, reliable, easy-to-interpret and cost-effective method compared to other typing methods. Moreover, the two newly developed multiplexes showed the same discriminatory power as all nine markers combined, indicating that multiplexes M3-1 and M9 are sufficient to type C. krusei.

Management of an Extremely Low Birth Weight Infant with Bilateral Renal Obstruction Caused by Candida albicans Fungus Balls

We report an extremely low birth weight infant with anuria caused by bilateral Candida albicans fungus balls it was treated with a combination of antifungal therapy, irrigation and pyelotomy. This lead to a recovery of renal function, after a follow-up of 77 month no more Candida was cultured from urine.

Maternal pregnancy-induced hypertension increases the subsequent risk of neonatal candidiasis: A nationwide population-based cohort study

OBJECTIVE

Neonatal candidiasis is a leading infectious cause of significant morbidity and mortality in premature birth mainly due to impaired physical barriers and immature immune system of fetus. Maternal pregnancy-induced hypertension (PIH) has been reported to be able to disturb the neonatal immune system, which could cause the increased possibility of neonatal infection. Therefore, we hypothesized that maternal PIH may increase the risk of neonatal candidiasis. The aim of this study was to evaluate whether PIH increased the risk of neonatal candidiasis and identify the predictive risk factors.

MATERIALS AND METHODS

Patients with newly diagnosed PIH between January 1, 2000, and December 31, 2013 were selected from the Taiwan National Health Insurance Research Database (NHIRD). For each patient in the PIH cohort, 4 subjects without PIH, matched for age and year of delivery, were randomly selected as the comparison cohort. A Cox proportional regression model was used to estimate the risks of neonatal candidiasis in both cohorts.

RESULTS

Among the 23.3 million individuals registered in the NHIRD, 29,013 patients with PIH and 116,052 matched controls were identified. Patients with PIH had a higher incidence of neonatal candidiasis than did those without PIH. According to the multivariate analysis, PIH (odds ratio [OR] = 2.08, 95% confidence interval [CI] = 1.11-3.19, p < 0.0228), single parity (OR = 1.91, 95% CI = 1.00-3.65, p < 0.0499), and preterm birth (OR = 3.57, 95% CI = 1.84-6.93, p = 0.0002) were independent risk factors for the development of neonatal candidiasis.

CONCLUSION

Patients who had a history of PIH was associated with an increased risk of having infants who develop neonatal candidiasis compared with those without PIH. Additionally, preterm birth was an independent risk factor for the development of neonatal candidiasis.

Epidemiology of Invasive Fungal Infections at Two Tertiary Care Neonatal Intensive Care Units Over a 12-Year Period (2000-2011)

We conducted a retrospective review of 168 patients with invasive fungal infections from January 2000 to December 2011 in 2 neonatal intensive care units. Patients with Candida bloodstream infection (BSI, n = 152) were further analyzed. C albicans was the most common species overall (47%); however, there was an increase in non–albicans sp from 2006 to 2011. Candida BSI clearance rates were lower in extremely low birth weight infants (77% vs 93%, P = .01) and in patients with C albicans infections (77% vs 91%, P = .01). Clearance rates improved from 2000 to 2005 (70% - 90%) to 2006 to 2011 (86% -100%). Combination antifungal use increased during the later years (73% vs 49%, P < .05) and in patients with end-organ dissemination (83% vs 54%, P < .05). We concluded that extremely low birth weight infants and C albicans infection are factors associated with nonclearance of Candida BSI. Successful clearance of Candida BSI improved in 2006 to 2011, perhaps due to increase in non–albicans species and the use of combination antifungals.

Candida albicans outbreak associated with total parenteral nutrition in the neonatal unit

BACKGROUND

The most frequently isolated fungi in patients using TPN belongs to the Candida genus. Various infections including venous catheter infections, fungemia, endocarditis and ophthalmitis may be encountered.

OBJECTIVE

Upon growth of Candida in the blood cultures from the pediatric (neonatal) unit of our hospital, a surveillance was performed in this unit and involving the health care workers. Clonal relationships of the isolates were investigated with molecular tests.

METHODS

Blood samples obtained from the patients in pediatric neonatal unit were studied with automatized blood culture [BacT/Alert (Bio Mιrioux, France)]. Yeast isolates from environmental surveillance cultures (TPN solutions, hands of healthcare personnel, ιtagθre, etc) and patients were identified as C. albicans with conventional methods and ID 32 C and ATB TM Fungus 3 (Biomerieux, France) kits. Clonal similarity was determined by using AP-PCR as initial method and we have also typified all strains by the method of REP-PCR (diversilab system,bioMιrieux). Finally; Pulsed Field Gel Electrophoresis (PFGE) was used for confirmation.

RESULTS

C. albicans was isolated in blood cultures of seven patients. Similar antifungal susceptibility patterns were observed in all isolates. AP-PCR and REP-PCR showed that the C. albicans isolates grown in the TPN solution and from the patients' blood cultures were clonally same strains. PFGE analysis further confirmed this clonality.

CONCLUSION

According to results of the molecular methods, we thought that a C. albicans outbreak had occurred in the neonatal pediatric unit, due to contamination of TPN solution.

Integrated measures for prevention of invasive Candida infections in preterm infants in a Chinese neonatal intensive care unit

BACKGROUND

The increasing incidence of invasive Candida infections (ICIs) in preterm infants in the neonatal intensive care unit (NICU) of Xinhua Hospital aroused our concern. We undertook a retrospective study to evaluate the efficacy of different preventive measures for ICI in preterm infants.

METHODS

Preterm infants with gestational age (GA) <33 weeks admitted between 2010 and 2013 were divided into 3 groups according to the preventive measures applied in different periods: the control group (CG), fluconazole group (FG), and integrated measures group (IMG). We analyzed the incidence of ICI and distribution of fungal pathogens in these 3 groups, and also evaluated the efficiency of various measures in preventing ICIs in preterm infants.

RESULTS

The study sample comprised 261 preterm infants born at <33 weeks GA, including 94 in the CG, 99 in the FG, and 68 in the IMG. The differences among the groups were not significant at baseline. ICI developed in 41 of the 261 infants (15.7%). The incidence of ICI varied significantly among the groups: 22.3% in the CG (21/94), 18.2% in the FG (18/99), and only 2.9% in the IMG (2/68) (P = .003). ICI was less frequent in the IMG compared with the CG (P <.001) and the FG (P = .003).

CONCLUSIONS

The integrated measures approach is meaningful for the prevention of ICIs in preterm infants in NICUs with many patients but inadequate medical resources in some developing countries.

Prevention of healthcare-associated infections in neonates: room for improvement

Infants in neonatal intensive care units (NICUs) are highly susceptible to infection due to the immaturity of their immune systems. Healthcare-associated infections (HCAIs) are associated with prolonged hospital stay, and represent a significant risk factor for neurological development problems and death. Improving HCAI control is a priority for NICUs. Many factors contribute to the occurrence of HCAIs in neonates such as poor hand hygiene, low nurse–infant ratios, environmental contamination and unnecessary use of antibiotics. Prevention is based on improving neonatal management, avoiding unnecessary use of central venous catheters, restricting use of antibiotics and H2 blockers, and introducing antifungal prophylaxis if necessary. Quality improvement interventions to reduce HCAIs in neonates seem to be the cornerstone of infection control.

Anuria in a solitary kidney with Candida bezoars managed conservatively

Renal involvement is regularly encountered in neonates with invasive candidiasis, especially when risk factors like congenital malformations of the renal tract or poor bladder emptying and preterm birth are present. However, complete obstruction of the renal collecting system by fungal balls is rare. Although conservative management has been advocated for partial obstruction, complete obstruction is considered an indication for surgical drainage. We report a patient with anuria and Candida albicans bezoars in a solitary kidney, suggesting post-renal acute kidney injury. The patient was treated with systemic fluconazole and peritoneal dialysis for 4 days. The fungus balls disappeared and renal function recovered.

CONCLUSION

Systemic antifungal therapy leads to clearance of obstructing fungus balls, and nephrostomy should be reserved for anuria due to bilateral complete obstruction with severe hydronephrosis. In these cases, temporary dialysis is a potential alternative.

Oral colonization: a possible source for candidemia in low-weight neonates

OBJECTIVE

To check the oral colonization in neonates at high-risk and to associate these cases with candidemia.

SUBJECTS AND METHODS

This study was conducted in the NICU. For six months, 125 high-risk neonates were investigated for oral colonization and septicemia by yeasts. From this total, 19 neonates had yeasts on the oral mucosae and 12 neonates developed fungemia. All of the 12 neonates with fungemia were included in the amount of 19 who have presented oral colonization by yeasts.

RESULTS

There was a species concordance between the yeasts of the oral mucosae and the blood in 6 neonates (50%) among the 12 neonates with oral colonization and septicemia at the same time. The yeasts isolated in these 6 cases regarding the species concordance were Candida albicans (5 cases, 83.4%) and Candida parapsilosis (1 case, 16.6%). All of the cases involving an association were confirmed by PFGE. All of the strains of yeasts involved in oral colonization and also blood presented the same karyotype. A total of 66.6% of the patients with strains in agreement progressed to death.

CONCLUSION

The results indicate the relevance of monitoring the oral microbiota, as a possible source of fungal infection, and assisting to develop appropriate therapeutic strategy.

A prospective study of the patterns and dynamics of colonization with Candida spp. in very low birth weight neonates

BACKGROUND

Knowledge of fungal colonization patterns in very low birth weight infants (VLBWI) admitted to the neonatal intensive care unit (NICU) is essential in understanding the process of fungal infections in neonates. We analyzed prospectively, during 2009-2010, the patterns and dynamics of fungal colonization in VLBWI, including timing, colonization sites, and species involved.

METHODS

Weekly skin, oropharynx, and rectum/stool surveillance fungal cultures were collected from admission until discharge in VLBWI in the NICU. None received antifungal prophylaxis.

RESULTS

Overall, 118 VLBWI provided 1723 samples; 34 (29%) had 104 positive samples at least once during the first 10 hospitalization weeks. Thirty-nine (33%) weighed < 1000 g; 68 were delivered by cesarean section. Candida albicans (57/104, 55%) and Candida parapsilosis (26/104, 25%) were the main fungi isolated. Eight (24%) VLBWI were colonized during the first week and 23 (68%) during the second week. No differences in colonization were recorded between cesarean section and vaginally delivered VLBWI. The colonization risk at least once during the first 10 weeks was 23% for skin, 14% for oropharynx, 27% for rectum/stool, and 38% for any anatomic site sampled. Persistent colonization was recorded in 5/34 (15%), while transient colonization was found in 14/34 (41%) VLBWI; 16/34 (47%) were discharged or died colonized with Candida spp. Candidemia was diagnosed in 4 (3%) VLBWI and previous/simultaneous colonization was found in 3/4.

CONCLUSIONS

The cumulative risk of colonization, at any sampled site and at least once during follow-up, was high. Initial colonization occurred most often during the first 2 weeks of life. Colonization dynamics were characterized by various persistence, disappearance, and recolonization patterns. Candidemia was rare.

Neonatal candidiasis: results of an 8 year study

BACKGROUND

The aim of the present study was to evaluate the risk factors, demographic features, treatment and clinical outcome associated with candidemia in a neonatal intensive care unit (NICU) within an 8 year period.

METHODS

The data of infants who were diagnosed as having candidemia, were evaluated.

RESULTS

Between January 2000 and December 2007, a total of 28 candidemia episodes were identified in 28 infants. A 1.1% candidemia incidence was documented in the neonatal intensive care unit (NICU). The species most frequently causing candidemia were Candida parapsilosis (57.1%), followed by C. albicans (42.9%). The main predisposing factors for candidemia with C. parapsilosis included presence of maternal pre-eclampsia, prematurity, prolonged mechanical ventilation, prolonged total parenteral nutrition and presence of jaundice. Retinopathy of prematurity and bronchopulmonary dysplasia were the most frequently seen underlying illnesses in infants with C. parapsilosis. In the present study, 13 infants (46.4%) had evidence of organ dissemination. The mortality rate was 42.8% in infants with candidemia. Mean leukocyte counts and mean C-reactive protein were significantly higher in neonates who died compared with those who survived.

CONCLUSION

Candida parapsilosis (57.1%) was the leading causative organism, followed by C. albicans (42.9%) in infants. The rate of organ dissemination in the present cases was high. The mortality rate was 42.8% in infants with candidemia.

Strategies for the prevention of neonatal candidiasis

Invasive fungal infections represent the third-leading cause of late-onset sepsis in very-low-birth-weight infants (VLBWI) and have a high rate of infection-associated mortality. The infants at high risk for fungal sepsis are VLBWI with presence of additional risk factors that contribute to increased colonization and concentration of fungal organisms. Colonization with Candida spp. in neonates is secondary to either maternal vertical transmission or nosocomial acquisition in the nursery. Multiple sites may become colonized and a direct correlation between fungal colonization and subsequent progression to invasive candidemia was determined. Randomized, single and multiple-center, placebo-controlled trials found intravenous fluconazole prophylaxis to be effective in decreasing fungal colonization and sepsis for at-risk preterm infants <1500 g birth weight. The prophylactic use of fluconazole was found to be safe with no significant development of fungal resistance. Fluconazole prophylaxis administered to preterm neonates with birth weight <1000 g and/or 27 weeks' gestation or less has the potential of reducing and potentially eliminating invasive fungal infections and Candida-related mortality.

[Invasive candidiasis in neonatal intensive care units]

In the USA, the incidence of invasive candidiasis in neonates is respectively 0.3% of infants over 2500 g and up to 20% of infants less than 1000 g. Their incidence is increasing. Two populations of newborn infants are particularly vulnerable: the premature infants and newborn infants with severe neonatal digestive diseases. Fifty percent of infants hospitalized in NICU are colonized with Candida at the end of the first week of hospitalization; a direct relationship exists between the importance of colonization and the invasive infection risk. C. albicans is the species most often responsible for invasive candidiasis in the newborn. These infections represent the third cause of related-catheter infection in the USA. Mortality rate in neonates linked to this disease is 20 to 50%; morbidity primarily concerns brain and lungs. Neonatal invasive candidiasis risk factors are known and a primary prevention is possible. The diagnosis of neonatal invasive candidiasis is difficult and often delayed because of a polymorphic clinical expression. Empiric and preemptive treatment are based on the use of amphotericin B. Prophylactic treatment using fluconazole of newborns with birth weight ≤ 1000 grams and/or gestational age ≤ 27 weeks gestation is recommended by the American Academy of Paediatrics and the Infectious Diseases Society of America. A better knowledge of French epidemiological data in this area would improve both the diagnosis and therapeutic management of this disease.

[Systemic congenital candidiasis, a rare condition in neonates: case report in a premature infant]

Congenital cutaneous candidiasis presenting at birth is very uncommon and is due to intra-uterine infection. The systemic form has to be considered when cutaneous signs are associated with sepsis symptoms.

CASE REPORT

A female infant was born by vaginal delivery at 35 weeks' gestation to a mother whose pregnancy had been complicated by urinary tract infection treated 3 days before delivery. The infant was admitted because of respiratory distress. Clinical features consisted of respiratory retraction signs associated with hepatomegaly and rash on the trunk. The white blood cell (WBC) count was 50 × 10(9)/L and C-reactive protein was negative. Maternofetal bacterial infection was suspected and intravenous antibiotics were prescribed. Over the next 6h, macules appeared on the trunk, back, and limbs, which changed after 24h into papulovesicular lesions over the trunk, back, limbs, palms, and scalp. Congenital candidiasis was suspected, confirmed by cultures from vesicle swabs and maternal vaginal discharge. The systemic form was considered because of respiratory distress requiring oxygen therapy for 4 days, hepatomegaly, elevated WBC count, and chest X-ray infiltrates. The infant was started on intravenous systemic antifungal therapy (fluconazole, 6 mg/day). Treatment was continued for 3 weeks. The rash resolved by desquamation after about 1 week and hepatomegaly disappeared. The infant remained well at follow-up.

Clinical aspects of invasive candidiasis in paediatric patients

Candida infections in paediatric patients are an important issue. They are associated with significant mortality, particularly in newborns and those with congenital immunodeficiencies. At present, there is limited knowledge regarding factors associated with an increased risk of developing invasive candidiasis in newborns and those with congenital immunodeficiencies, although there have been a number of studies conducted to characterize these risk factors. These studies have suggested that, in neonates, the most important of these factors is colonization, whereas in paediatric patients with congenital immunodeficiencies, risk factors may differ according to the specific deficiency present. Regarding treatment of invasive candidiasis in paediatric patients, fluconazole is considered an appropriate choice, although the method for determining treatment strategies for each patient should be the same as that used for such decisions in adult patients.

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.

Cytotoxicity of Aspergillus strains isolated from the neonatal intensive care unit environment

PURPOSE

It is essential in the medical care for immunocompromised patients that the environment should create minimal infection risk. Particularly, it concerns fungal infections. Fungi belonging to the Aspergillus genus are second frequent group of nosocomial pathogens producing opportunistic infections.

MATERIAL AND METHODS

The objective of the study was evaluation of prevalence and cytotoxicity of selected Aspergillus strains isolated from the neonatal intensive care unit environment. During 5 consecutive days, 30 samples of indoor air and 120 imprints from the ward environment were collected. Cytotoxicity of 17 strains was evaluated using a MTT (3-(4,5-dimethylthiazol-2-yl) 2,5 diphenyltetrazolium bromide) test.

RESULTS

Mean numbers of fungi in the indoor air varied from 50 to 2370 c.f.u.xm-3 while in the imprints from 0.04 to 8.83 c.f.u.xcm-2. Moulds were isolated from most of the materials. All of the 17 strains subject to MTT test were cytotoxic.

CONCLUSION

All of the Aspergillus strains isolated from the neonatal intensive care unit were cytotoxic. Cytotoxic Aspergillus strains present in the environment of immunocompromised patients may be potentially dangerous to them.

Febrile neutropenia in children with cancer: a retrospective Norwegian multicentre study of clinical and microbiological outcome

Our objective was to describe clinical and laboratory characteristics, treatment and outcome among Norwegian children with cancer suffering from chemotherapy-induced febrile neutropenia (FN). We retrospectively reviewed data on paediatric FN episodes in 7 Norwegian hospitals during a 2.5-y period. A total of 236 episodes of FN occurred in 95 children. Acute lymphoblastic leukaemia was the most common diagnosis (49 patients). Blood cultures yielded growth in 39 episodes (17%). Primary empirical antibiotic regimens could be assigned to 2 main groups: 1) benzylpenicillin or ampicillin and an aminoglycoside (58%) or 2) a regimen based on third-generation cephalosporins (42%). There were no statistically significant differences in outcome between the 2 regimens in terms of need to change initial antibiotic treatment, d of fever or maximum C-reactive protein values. One infection-related death (fungal septicaemia) occurred during the study period. We conclude that incidence of septicaemia and clinical outcome is similar to recent international trials on paediatric FN, but antibiotic treatment in Norway differs from international guidelines. However, patients in our study were successfully and safely treated, irrespective of the primary empirical antibiotic regimen.

C. albicans colonization of human mucosal surfaces

BACKGROUND

Candida albicans is a low level commensal organism in normal human populations with the continuous potential to expand and cause a spectrum of clinical conditions.

METHODOLOGY/PRINCIPAL FINDINGS

Using ex vivo human organ cultures and populations of primary human cells, we have developed several related experimental systems to examine early-stage interactions between C. albicans and mucosal surfaces. Experiments have been conducted both with exogenously added C. albicans and with overtly normal human mucosal surfaces supporting pre-existing infections with natural isolates of Candida. Under different culture conditions, we have demonstrated the formation of C. albicans colonies on human target cells and filament formation, equivalent to tissue invasion.

CONCLUSIONS/SIGNIFICANCE

These organ culture systems provide a valuable new resource to examine the molecular and cellular basis for Candida colonization of human mucosal surfaces.