Indian Pediatrics 2004; 41:712-715 

Trends in Neonatal Septicemia: Emergence of Non-albicans Candida

In a prospective analysis, blood from 660 neonates admitted to neonatal Intensive Care Unit (NICU) of a teaching hospital with clinical suspicion of septicemia was cultured to look for etiological agents with particular reference to role of Candida species. Blood culture specimens from two different sites at same time were obtained to rule out possibility of a Candida isolate being a mere contaminant. Due to technical difficulties, this was possible in only 338 neonates (Group I); from remaining 322 neonates only single specimen was available (Group II). Candida was isolated from total 90 neonates (isolation rate 13.6%) and it was the single most common isolate. Majority were non-albicans Candida (germ tube test negative - 76/90). In group I, Candida was isolated from 66 neonates, of these 49 grew Candida in both specimens (significant candidemia). 44 records were available for analysis. Low birth weight was found in 73.3%. Crude mortality was 52.6%. A peak in isolation rate of Candida was noted (isolation rate 27%, p<0.05) in month of February. In Group I, 49 of the total 66 (74.2%) isolates of Candida were significant, suggesting that three in every four Candida isolated from blood can be significant. Non-albicans Candida are emerging as important pathogens for neonatal septicemia.

Key words: Candida species, candidemia, Neonatal septicemia, Neonatal ICU

Over the last 2 decades, yeasts have become important nosocomial pathogen, Candida species being the most frequent isolate. This rise is largely attributed to extensive use of broad-spectrum antibiotics and advances in medical field, which contri-bute towards the large pool of susceptible population available for these opportunistic pathogens(1,2). Recently, non-albicans Candida have emerged as important opportunistic pathogen, notably C. tropicalis, C. glabrata and C. parapsilosis(3). This could be because of selection of lesser susceptible non-albicans species due to frequent use of fluconazole(4). Importance of Candida spp in nursery and intensive care setup is increasingly being recognized. Candida spp account for 9 to 13% of all blood stream isolates in neonatal intensive care unit (NICU)(5,6). Common use of broad-spectrum antibiotics, low birth weight (LBW), pre-maturity and intravenous catheter etc. makes neonates prone to candidemia(2,7-12).

Here we are presenting our findings that were observed while investigating the causes of septicemia in a neonatal ICU.

Subjects and Methods

The study was conducted in Microbiology and Pediatrics department at KGMU, Lucknow, India. This is a tertiary care, 2500 bedded hospital. In a prospective analysis between August 2002 to April 2003; blood from 660 neonates (<28 days) admitted in NICU with clinical suspicion of septicemia was collected for culture. We were noticing an increase in the isolation rate of non-albicans Candida over last few months from cases of neonatal septicemia. Since Candida can be part of skin flora of neonates admitted in hospital, its isolation from blood culture may reflect contamination from skin flora. To rule out this, we planned present study with the aim of collecting two blood culture specimens from each neonate enrolled. Due to technical difficulties of collecting blood from a sick neonate; two specimens each were received from only 338 neonates (Group I); 2 mL of venous blood was collected for culture under aseptic conditions simultaneously from two different sites. From remaining 322 neonates, only single specimen of blood was available for culture (Group II).

Blood specimen was inoculated into culture bottle with 20 mL of brain heart infusion broth and subcultures were made on 5% sheep blood agar and Sabouraud’s dextrose agar after 24 hours and on 6th day(13). Significant candidemia was defined as growth of Candida in both samples from a patient to rule out the possibility of the isolate being a contaminant from skin flora. Germ tube test was put for all Candida isolates and they were reported as C. albicans or non-albicans Candida. Significant Candida recovered from fourteen cases of candidemia during the month of February were further identified using sugar fermentation and assimilation tests(14).

Results

Blood cultures from 660 cases with clinical suspicion of septicemia were processed. Candida was isolated from a total of 90 neonates (isolation rate 13.6%); Gram negative and Gram positive organisms from 158 and 129 neonates (isolation rate 23.9% and 19.5%) respectively. Infection rate due to Candida was calculated to be 77/1000 discharges in NICU.

Of 338 neonates in Group 1, 66 grew Candida from their blood, 49 of these neonates grew Candida in both specimens i.e., significant candidemia (14.5 %). In remaining 17 cases, Candida was isolated from only single specimen. From Group II Candida was isolated in 24/322 neonates. Majority of the isolates were non-albicans Candida (GTT negative, 76/90).

Of 49 neonates who had significant candidemia, records of 44 were available for analysis, one of these neonate had two episodes of candidemia, so a total of 43 cases were further analyzed. Mean age of neonate at the time of investigation was 3.4 days (ranging from just born to 19 days), male is to female ratio was 1:2. Average duration of stay in ICU was 9.6 days. Other associated findings were LBW 73.3% (P<0.05), prematurity 38.6%, perinatal asphyxia 35.7%, respiratory distress 33.3%, jaundice 28.5% and meconium aspiration in 11.9% of neonates.

Crude mortality rate was 52.6% in culture proven significant candidemia group. Details of anti-fungal treatment were not available. On further analysis we noticed a peak in isolation rate of Candida in month of February, 14 of the 52 blood specimen received in this month grew Candida (isolation rate 27%) and it was found to be significantly higher than in any other month (P <0.05). These 14 Candida isolates were further speciated, and 9 were found to be C. tropicalis, four C.glabrata and one isolate was C.guillermondii.

Discussion

In the present study Candida was the commonest isolate from neonates clinically suspected to have septicemia. Majority (76/90) of the isolates were non-albicans Candida. Blood stream infection cases due to non-albicans Candida have been reported to range from 14-100%(1). In a retrospective analysis in an NICU, authors found >11 fold increase in rate of candidemia over a fifteen year period (2.5/1000 discharges in 1981 to 28.5/1000 discharges in 1995(15). A shift from C.albicans to non-albicans was noted by this group, C. parapsisosis being most prevalent isolate in latter years. Similar trend was also observed by an Indian group in their study done over a period of ten years(6). Previous study during year 2001 from our hospital showed candidemia to be present in 6% of neonates with suspected septicemia(17), Candida was not further identified. There is marked increase in rate of blood stream infection caused by Candida, over last two years at our center.

Various workers have reported Candida as cause for neonatal septicemia. Systemic candidiasis in 3.2% of admissions in NICU has been reported by one group(18), in their study mean age at the time of infection was 10.4 days, 95% had LBW and 94% of neonates were preterm. They found Candida attributed mortality to be 17%, C. tropicalis, C. albicans and C. guillermondii were the commonest isolates. Systemic candidiasis was found in 0.57% of neonatal admissions in a prospective multicenter analysis, C. albicans being the commonest species and LBW the commonest associated factor(19).

An outbreak of candidemia during month of February (isolation rate 27%) was largely responsible for overall high infection rate due to Candida in this study (77/1000 discharges in NICU); apart from that one month the isolation rate was between 8-16% in accord-ance with other published reports(5,6,10). High rate of fungemia (22.8%) in neonates has been reported by a group and they also noted that 71.4% of neonates were colonized with yeasts within 24 hours of admission and colonization was more in LBW babies(12).

Candidemia is generally associated with high rnortality. In our study crude mortality rate of 52.6% was observed in neonates with significant candidemia Reported attributable mortality ranges from 6-22%. Mortality rates as high as 60-80% have been reported in candidemia in adult patients(21).

Several risk factors have been cited as predisposing to candidemia in neonates including underlying illness, LBW, broad-spectrum antibiotic, asphyxia neonatorum, invasive interventions, hyperalimentation and TPN, etc. (2,7-12). In our study LBW was the commonest associated finding present in 73.3% neonates with candidemia.

The findings from Group I, in which 49 of the total 66 (74.2%) isolates of Candida were significant, suggests that three in every four Candida isolated from blood culture is a significant isolate. This is an important finding that emerges from this study, as Candida isolated from single blood culture is some-times ignored as a mere skin contaminant.

Contributors: JA analyzed and interpreted the data. SB and GKM were involved in acquisition of data. JA and SB drafted the manuscript. AJ conceived and designed the study, revised it critically and interpreted data. All authors finally approved the manuscript.

Funding: None.

Competing interests: None stated.

 References

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