Blood culture isolates during 6 years in a tertiary neonatal intensive care unit

Sepsis profile and outcome of preterm neonates admitted to neonatal intensive care unit of Cairo University Hospital

Background

This study demonstrates the experience of the neonatal intensive care unit (NICU) of a tertiary referral center in Egypt in management of prematures with neonatal sepsis. This retrospective study included preterm neonates admitted to NICU with clinical and/or laboratory diagnosis of sepsis. Blood culture was done followed by antimicrobial susceptibility testing for positive cases. Neonates with sepsis were classified into early onset sepsis (EOS) and late onset sepsis (LOS). Hematological scoring system (HSS) for detection of sepsis was calculated.

Results

The study included 153 cases of neonatal sepsis; 63 (41.2%) EOS and 90 (58.8%) LOS. The majority of the neonates had very low or moderately low birth weight (90.9%). All neonates received first-line antibiotics in the form of ampicillin-sulbactam, and gentamicin. Second-line antibiotics were administered to 133 neonates (86.9%) as vancomycin and imipenem-cilastatin. Mortalities were more common among EOS group (p < 0.017). Positive blood cultures were detected in 61 neonates (39.8%) with a total number of 66 cultures. The most commonly encountered organisms were Klebsiella MDR and CoNS (31.8% each). Klebsiella MDR was the most predominant organism in EOS (28.9%), while CoNS was the most predominant in LOS (39.2%) The detected organisms were divided into 3 families; Enterobacteriaceae, non-fermenters, and Gram-positive family. There 3 families were 100% resistant to ampicillin. The highest sensitivity in Enterobacteriaceae and Non-fermenters was for colistin and polymyxin-B. An HSS of 3–8 had a sensitivity and specificity of 62.3% and 57.6%, respectively for diagnosis of culture-proven sepsis.

Conclusion

Neonatal sepsis was encountered in 21.5% of admitted preterm neonates; LOS was more common (58.8%). Mortality was 51.6%. Klebsiella MDR and CoNS were the most commonly encountered organisms in both EOS and LOS. The isolated families were 100% resistant to ampicillin. The hematological scoring system (HSS) showed limited sensitivity for detection of sepsis.

Study of Antibiotic Susceptibility among Bacterial Isolates in Neonatal Intensive Care Unit of a Tertiary Care Hospital: A Descriptive Cross-sectional Study

Introduction:

Neonatal sepsis is a major cause of neonatal morbidity and mortality worldwide, especially in developing countries like Nepal. Antibiotic resistance among microorganisms poses new challenges in the treatment of neonatal sepsis. The present study is conducted with the objectives of determining clinico-bacteriological profile and antibiotic susceptibility among isolated bacteria in a neonatal intensive care unit.

Methods:

A descriptive cross-sectional study was conducted from January 1, 2017, to December 31, 2019, in the neonatal intensive care unit of a tertiary care hospital after obtaining ethical clearance from Institutional Review Committee (Ref: 2020-064). The sample size was calculated and 77 neonates with culture-proven sepsis were included in the study. The antibiotic susceptibility tests of the isolates were done by Kirby-Bauer disc diffusion method. Data entry was done in Statistical Packages for the Social Sciences version 20.

Results:

Of the 841 specimens (blood, cerebrospinal fluid, urine, tracheal aspirate and pus) processed for culture, bacteria were isolated in 84 (10.0%) specimens. Among the 84, gram-negative bacilli were the predominant isolates 76 (90.5%); of which Acinetobacter baumannii was the most common 27 (32.1%). Both the Gram-negative and the Gram-positive bacteria showed high resistance to Penicillin and Cephalosporins. Gram-negative bacteria showed maximum sensitivity to Colistin, Carbapenems, Tigecycline and Fluoroquinolones. Gram-positive bacteria showed maximum susceptibility to Amikacin, Vancomycin and Carbapenems.

Conclusions:

Judicious use of antibiotics based on the updated knowledge of prevalent organisms in the local hospital setting and their antibiotic sensitivity pattern is of utmost importance for the effective treatment of neonatal sepsis.

Etiology of early onset neonatal sepsis in neonatal intensive care unit - Mansoura, Egypt

INTRODUCTION

This study was conducted to find out the bacterial causes of early onset neonatal sepsis and their susceptibility pattern for different classes of antibiotics in neonates admitted to neonatal intensive care unit (NICU) of Mansoura-Egypt.

METHODS

A descriptive cross-sectional study was conducted. All admitted newborns to our study were infants at <72 hours of age with clinical features of sepsis or product of an in-house delivery at Mansoura University Hospital with risk factors for neonatal sepsis. Identification of Gram-negative isolates was confirmed by API 20E kits (bioMerieux). Antibiotic susceptibility was performed by Kirby-Bauer disc diffusion method. Bacteria resistant to ≥3 antimicrobial classes were counted as multidrug resistant.

RESULTS

One hundred eighty eight babies were admitted to our study. Positive blood culture was reported in 34.6% of newborn infants with prevalence of 4.02/1,000 live births. The most common isolated bacteria in early onset neonatal sepsis were coagulase negative staphylococci followed by Klebsiella pneumoniae and Serratia marcescens. The Gram-positive bacteria showed high resistance to ampicillin 93.9% while all the isolates were susceptible to vancomycin. The isolated Gram-negative bacteria were highly resistant to ampicillin [96.9%], amoxicillin-clavulanic acid [90.6%], cefotaxime [84.4%] and ceftazidime [84.4%]. Best sensitivity among all isolates was observed to imipenem. Multidrug resistance was observed among 45.5% of the Gram-positive and 68.8% of Gram-negative isolates.

CONCLUSION

Appropriate identification of the source of infection and initiation of an effective management can reduce both mortality and morbidity associated with neonatal sepsis. The challenge is to initiate immediate empirical antibiotic therapy according to a strictly implemented updated antibiotic policy based on an individualized community established antimicrobial sensitivity pattern of microorganisms causing early onset neonatal sepsis.

Perinatal Mortality Associated with Positive Postmortem Cultures for Common Oral Flora

Introduction. To investigate whether maternal oral flora might be involved in intrauterine infection and subsequent stillbirth or neonatal death and could therefore be detected in fetal and neonatal postmortem bacterial cultures. Methods. This retrospective study of postmortem examinations from 1/1/2000 to 12/31/2010 was searched for bacterial cultures positive for common oral flora from heart blood or lung tissue. Maternal age, gestational age, age at neonatal death, and placental and fetal/neonatal histopathological findings were collected. Results. During the study period 1197 postmortem examinations (861 stillbirths and 336 neonatal deaths) were performed in our hospital with gestational ages ranging from 13 to 40+ weeks. Cultures positive for oral flora were identified in 24 autopsies including 20 pure and 8 mixed growths (26/227, 11.5%), found in 16 stillbirths and 8 neonates. Microscopic examinations of these 16 stillbirths revealed 8 with features of infection and inflammation in fetus and placenta. The 7 neonatal deaths within 72 hours after birth grew 6 pure isolates and 1 mixed, and 6 correlated with fetal and placental inflammation. Conclusions. Pure isolates of oral flora with histological evidence of inflammation/infection in the placenta and fetus or infant suggest a strong association between maternal periodontal conditions and perinatal death.

Broad-spectrum Antibiotic Plus Metronidazole May Not Prevent the Deterioration of Necrotizing Enterocolitis From Stage II to III in Full-term and Near-term Infants: A Propensity Score-matched Cohort Study

Necrotizing enterocolitis (NEC) is the most common and frequently dangerous neonatal gastrointestinal disease. Studies have shown broad-spectrum antibiotics plus anaerobic antimicrobial therapy did not prevent the deterioration of NEC among very low birth preterm infants. However, few studies about this therapy which focused on full-term and near-term infant with NEC has been reported. The aim of this study was to evaluate the effect of broad-spectrum antibiotic plus metronidazole in preventing the deterioration of NEC from stage II to III in full-term and near-term infants.A retrospective cohort study based on the propensity score (PS) 1:1 matching was performed among the full-term and near-term infants with NEC (Bell stage ≥II). All infants who received broad-spectrum antibiotics were divided into 2 groups: group with metronidazole treatment (metronidazole was used ≥4 days continuously, 15 mg/kg/day) and group without metronidazole treatment. The depraved rates of stage II NEC between the 2 groups were compared. Meanwhile, the risk factors associated with the deterioration of stage II NEC were analyzed by case-control study in the PS-matched cases.A total of 229 infants met the inclusion criteria. Before PS-matching, we found the deterioration of NEC rate in the group with metronidazole treatment was higher than that in the group without metronidazole treatment (18.1% [28/155] vs 8.1% [6/74]; P = 0.048). After PS-matching, 73 pairs were matched, and the depraved rate of NEC in the group with metronidazole treatment was not lower than that in the group without metronidazole treatment (15.1% vs 8.2%; P = 0.2). Binary logistic regression analysis showed that sepsis after NEC (odds ratio [OR] 3.748, 95% confidence interval [CI] 1.171-11.998, P = 0.03), the need to use transfusion of blood products after diagnosis of NEC (OR 8.003, 95% CI 2.365-27.087, P = 0.00), and the need of longer time for nasogastric suction were risk factors for stage II NEC progressing to stage III (OR 1.102, 95% CI 1.004-1.21, P = 0.04).Broad-spectrum antibiotic plus metronidazole may not prevent the deterioration of NEC in full-term and near-term infants. Those infants who had sepsis required transfusion of blood products, and needed longer time for nasogastric suction after stage II NEC was more likely to progress to stage III.

Epidemiology of Neonatal Sepsis and Implicated Pathogens: A Study from Egypt

Prospective analytic study was conducted in NICUs of three Egyptian Neonatal Network (EGNN) participants in Mansoura Hospitals in Egypt over a period of 18 months from March 2011 to August 2012. By using EGNN 28-day discharge form, all demographic, clinical, and laboratory data were recorded and studied. During the study period, 357 neonates were diagnosed as suspected sepsis with an incidence of 45.9% (357/778) among the admitted neonates at the three neonatal intensive care units. 344 neonates (sex ratio = 1.3:1) were enrolled in the study in which 152 (44.2%) were classified as early onset sepsis EOS (≤72 hr) and 192 (55.8%) as late onset sepsis LOS (>72 hr). Among the LOS cases, 33.9% (65/192) were caused by nosocomial infections. In 40.7% (140/344), sepsis was confirmed by positive blood culture. The total mortality rate for the proven neonatal sepsis was 51% (25/49) and 42.9% (39/91) for EOS and LOS, respectively. Coagulase negative staphylococci were predominant isolates in both EOS and LOS, followed by Klebsiella pneumoniae. Most of the bacterial isolates had low sensitivity to the commonly used empiric antibiotics. However, 70.1% (89/127) exhibited multidrug resistance. Best sensitivities among Gram-positive isolates were found against imipenem, ciprofloxacin, vancomycin, and amikacin.

Disseminated, large-sized neonatal pneumatoceles: the wait-and-see strategy

Pulmonary pneumatoceles are thin-walled, air-filled cysts that develop within the lung parenchyma. Most often, they occur as a sequel of acute pneumonia, commonly caused by Staphylococcus aureus in children. Limited data are available about infective pulmonary cysts in newborns. We report a case of a newborn, who developed multiple pneumatoceles after Escherichia coli pneumonia.

Neonatal morbidity and mortality in a Tanzanian tertiary care referral hospital

In developing countries, neonatal mortality accounts for 50-70% of infant mortality. The purpose of this study was to describe morbidity and mortality patterns, with a focus on neonatal infections, in a Tanzanian special care baby unit (SCBU). During a 3-month period, 246 consecutive admissions to the SCBU at Kilimanjaro Christian Medical Centre were audited. Prematurity, low birthweight and suspected infection accounted for 61% of all admissions. The overall mortality rate was 19%, but varied considerably according to gestational age, birthweight and diagnosis. Thirty-one neonates (two-thirds of all deaths) died during the 1st 24 hours of life. Of 27 infants admitted on grounds of perinatal asphyxia, 11 (41%) died, and, of 19 infants with a gestational age <31 weeks, 13 (68%) died. More than two-thirds of all infants were treated with antibiotics. Septicaemia confirmed by blood culture was found in 16 cases. The susceptibility pattern of bacterial isolates did not indicate high rates of resistance to commonly used antibacterial agents. A reduction in the number of preterm deliveries and improved perinatal care to avoid and treat perinatal asphyxia would be the two most important measures in reducing neonatal mortality in this setting.

Incidence, aetiology and resistance of late-onset neonatal sepsis: a five-year prospective study

AIM

Investigate the incidence, etiological pattern and the antimicrobial resistance of late-onset neonatal infections over a period of 5 years.

METHODS

Longitudinal audit of neonatal sepsis from January 2005 to December 2009, in the main maternity hospital in Kuwait. Late-onset neonatal infection was defined as the culture of a single potentially pathogenic organism from blood or cerebrospinal fluid from an infant older than 6 days in association with clinical or laboratory findings consistent with infection.

RESULTS

The overall incidence was 16.9 (95% confidence interval: 15.8-18.0) episodes per 1000 live births. The commonest pathogen was coagulase-negative Staphylococcus, 339 (35.7%), while Klebsiella was the most common gram-negative infection, 178 (18.8%). Escherichia coli, Enterococcus and Enterobacter spp were each responsible for 6% of all infections. Candida caused 104 (11.0%) infections. The general pattern of infection remained unchanged over the study period. Case fatality was 11.7% (95% confidence interval: 9.7-13.9%) and was high for Pseudomonas (18.4%) and Candida (22.1%) infections. Approximately 24 and 20% of Klebsiella infections were resistant to cefotaxime and gentamicin, respectively, while 28 and 24% of Escherichia coli infections were resistant to cefotaxime and gentamicin, respectively.

CONCLUSION

The incidence of late-onset infection in Kuwait is high, resembling that in resource-poor countries. The high incidence coupled with low case fatality provides an example for settings where tertiary care is introduced without strict measures against nosocomial infections. Prevention against nosocomial infections in neonatal units has the potential to further reduce neonatal mortality in these settings.

Trends in epidemiology of neonatal sepsis in a tertiary center in Korea: a 26-year longitudinal analysis, 1980-2005

There were many reports of longitudinal changes in the causative organisms of neonatal sepsis in Western countries but few in Asia. We aimed to study longitudinal trends in the epidemiology of neonatal sepsis at Seoul National University Children's Hospital (SNUCH), a tertiary center in Korea, and compared the results to previous studies of Western countries. The medical records of all of the neonates who were hospitalized at SNUCH from 1996 to 2005 with positive blood cultures were reviewed. We also compared the findings to previous 16-yr (1980-1995). One hundred and forty-nine organisms were identified in 147 episodes from 134 infants. In comparison with the previous 16-yr studies, there was a decrease in the number of Escherichia coli infections (16.2% vs 8.7%: odds ratio [OR] 0.495; 95% confidence interval [CI], 0.255-0.962; P = 0.035), but an increase in Staphylococcus aureus (16.6% vs 25.5%: OR 1.720; 95% CI, 1.043-2.839; P = 0.033) and fungal infections (3.3% vs 18.7%: OR 6.740; 95% CI, 2.981-15.239; P < 0.001), predominantly caused by Candida species. In conclusion, the incidence of sepsis caused by E. coli decreases, but S. aureus and fungal sepsis increases significantly. Compared with Western studies, the incidence of sepsis caused by S. aureus and fungus has remarkably increased.

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.

Staphylococcal skin infections in children: rational drug therapy recommendations

Staphylococcus aureus remains one of the most common and troublesome of bacteria causing disease in humans, despite the development of effective antibacterials and improvement in hygiene. The organism is responsible for over 70% of all skin and soft tissue infections in children and accounts for up to one-fifth of all visits to pediatric clinics. Skin and soft tissue infections that are predominantly caused by S. aureus include bullous and non-bullous impetigo, folliculitis, furunculosis, carbunculosis, cellulitis, surgical and traumatic wound infections, mastitis, and neonatal omphalitis. Other skin and soft tissue infections may also be caused by S. aureus but are often polymicrobial in origin and require special consideration. These include burns, decubitus ulcers (particularly in the perianal region), puncture wounds of the foot, as well as human and mammalian bites. Treatment of staphylococcal skin infections varies from topical antiseptics to prolonged intravenous antibacterials, depending on severity of the lesions and the health of the child. The treatment of choice for oral antibacterials remains the penicillinase-resistant penicillins such as flucloxacillin. Cefalexin and erythromycin are suitable cost-effective alternatives with broader cover, although care must be taken with the use of macrolides because of development of resistance to multiple families of antibacterials, particularly the lincosamides. Other cephalosporins such as cefadroxil and cefprozil are also effective, can be given once daily and have a better tolerability profile -- while azithromycin has a further advantage of a 3-day course. However, all of these agents are more expensive. Although the antibacterials have been given for 10 days in most clinical trials, there is no evidence that this duration is more effective than a 7-day course. In children requiring intravenous therapy, ceftriaxone has a major advantage over other antibacterials such as sulbactam/ampicillin and cefuroxime in that it can be given once daily and may, therefore, be suitable for outpatient treatment of moderate-to-severe skin infections. Newer-generation cephalosporins and loracarbef are also effective and have a broader spectrum of activity, but do not offer any added benefit and are significantly more expensive. Skin and soft tissue infections due to methicillin-resistant S. aureus (MRSA) are still relatively uncommon in children. Well children with community-acquired MRSA infections can be treated with clindamycin or trimethoprim-sulfamethoxazole (cotrimoxazole), but must be observed closely for potentially severe adverse effects. In severe infections, vancomycin remains the treatment of choice, while intravenous teicoplanin and clindamycin are suitable alternatives. Linezolid and quinupristin/dalfopristin are currently showing great promise for the treatment of multi-resistant Gram-positive infections. While the choice of antibacterial is important, supportive management, including removal of any infected foreign bodies, surgical drainage of walled-off lesions, and regular wound cleaning, play a vital role in ensuring cure.

Persistent bacteremia and severe thrombocytopenia caused by coagulase-negative Staphylococcus in a neonatal intensive care unit

OBJECTIVE

Coagulase-negative Staphylococcus (CoNS) is the most frequent cause of late-onset sepsis in NICUs, but mortality is rare and morbidity is unusual. We report a new syndrome of CoNS sepsis characterized by significant morbidity and persistent bacteremia despite aggressive antibiotic therapy and no identified focus of infection.

METHODS

We conducted a retrospective review of infants in the NICU with CoNS bacteremia between 2000 and 2002. Statistical analysis included an initial exploratory analysis followed by logistic regression. Microbiological identification of all isolates and molecular typing were performed.

RESULTS

Thirty-one neonates with persistent CoNS bacteremia were compared with 60 randomly selected neonates from a group of 140 with nonpersistent CoNS bacteremia. The clinical manifestations at presentation, gestational ages, and birth weights were similar in the 2 groups. Thrombocytopenia was present in 26 (84%) neonates with persistent CoNS bacteremia but only in 8 (13%) neonates in the nonpersistent group. Central venous catheterization increased the risk for persistent CoNS bacteremia, but 42% of the persistent group was never catheterized. Staphylococcus epidermidis was the most common isolate in both groups. Molecular typing failed to identify a predominant clone.

CONCLUSIONS

The syndrome of persistent CoNS septicemia is remarkable for thrombocytopenia and persistence in the absence of central venous catheterization. Clinical manifestations at presentation and demographic characteristics did not discriminate between the persistent and nonpersistent groups. We did not identify the emergence of a particularly virulent clone, but it is possible that some strains of CoNS have acquired the capacity to persist under different conditions.

The efficacy of two different lipid-based amphotericin B in neonatal Candida septicemia

BACKGROUND

Fungal sepsis is becoming more frequent in neonatal intensive care units (NICU) and has a high mortality rate due to the invasive nature of the disease and to the insufficiency of low doses and high incidence of renal problems with effective doses of amphotericin B. New generation lipid formulated amphotericin B preparations may be more efficient because they are less toxic to be applied in target doses. However, there is limited experience in neonates and preterm infants.

METHODS

The charts of 917 patients admitted to NICU between 2001 and 2003 were reviewed and the data of 21 patients with systemic Candida infection, requiring different amphotericin B therapy, were analyzed.

RESULTS

Infants with fungal septicemia were treated with amphotericin B lipid complex (Abelcet)(n = 10) and liposomal amphotericin B (AmBisome)(n = 9) for a mean duration of 21 and 18 days. The mean gestational age of the patients was 30.9 +/- 4.2 weeks and mean birth weight was 1536 +/- 714 g. Two patients in the Abelcet group and one patient in the AmBisome group died during therapy. Fungal eradication was achieved in 16 surviving infants and mean eradication time was 8.1 +/- 2.6 days and mean duration of therapy was 19.2 +/- 4.1 days. Mortality rates related to treatment failure were similar being 20% in the Abelcet group and 11% in the AmBisome group. No patient showed severe side-effects from the antifungal therapy; the incidence of minimal side-effects were similar in both groups and they were elevated serum transaminase levels in six patients, increased serum creatinine in one patient and hypokalemia in one patient.

CONCLUSION

Both preparations have the same benefits for the treatment of neonatal fungal sepsis and they can be used safely in neonates including very low birth weight infants. However, the clinician must keep in mind the cost of treatment.

Seventy-five years of neonatal sepsis at Yale: 1928-2003

OBJECTIVE

Yale-New Haven Hospital (Y-NHH) has maintained the longest running, single-center longitudinal database of neonatal sepsis, started in 1928. The objective of this study was to update this database with review of neonatal sepsis cases at Y-NHH to identify longitudinal trends in demographics, pathogens, and outcome.

METHODS

Records of infants with positive blood cultures obtained while they were inpatients in the NICU at Y-NHH from 1989 to 2003 were reviewed retrospectively. Records of infants who were < or =30 days of age, had positive blood cultures, and were hospitalized at Y-NHH outside the NICU from the same period were also reviewed, and all findings were compared with 60 years of preexisting data.

RESULTS

A total of 862 organisms were identified in 755 episodes of sepsis from 647 infants. The percentage of cases of early-onset sepsis decreased and late-onset sepsis increased compared with the previous 10-year study period. A marked increase in cases as a result of commensal species was observed, particularly in preterm infants who had indwelling central vascular catheters, were receiving parenteral nutrition, and required prolonged mechanical ventilation. The overall percentage of sepsis caused by group B streptococcus and Escherichia coli decreased. No episodes of sepsis from Streptococcus pneumoniae or S pyogenes, common in the early years of the survey, were observed. The sepsis-related mortality rate steadily decreased, from 87% in 1928 to 3% in 2003.

CONCLUSIONS

The demographics, pathogens, and outcome associated with neonatal sepsis continue to change. The increase in late-onset sepsis in preterm infants who required prolonged intensive care indicates that strategies to prevent infection are urgently needed for this population of infants.

Septicemia in the first week of life in a Norwegian national cohort of extremely premature infants

OBJECTIVES

To investigate the incidence, causes, predictors, and outcomes of septicemia in the first week of life in a national cohort of extremely premature infants.

METHODS

A prospective study of survival of all infants with gestational age of <28 weeks or birth weight of <1000 g who were born in Norway in 1999-2000 was performed. Data on the maternal prenatal history, delivery, and neonatal course, including detailed information on episodes of microbiologically verified septicemia, were collected on predefined forms. Septicemia was reported in 2 groups, ie, episodes diagnosed on the day of delivery (ie, very early-onset septicemia [VEOS]) and episodes diagnosed from day 2 to day 7 of life (ie, early-onset septicemia [EOS]). Logistic regression models were used for the selection of variables for predictor analysis in each group.

RESULTS

Of 462 included infants, VEOS occurred for 15 (32.5 per 1000 population) and EOS for 15 (35.5 per 1000 population). The most prevalent bacteria were Escherichia coli in VEOS (n = 9) and staphylococci (coagulase-negative staphylococci and Staphylococcus aureus) (n = 15) in EOS. Case fatality rates were 40% and 13%, respectively. Independent predictive factors for VEOS were clinical chorioamnionitis (odds ratio [OR]: 10.5; 95% confidence interval [CI]: 3.3-33.4) and high maternal age (OR: 1.2; 95% CI: 1.0-1.3), whereas not receiving systemic antibiotic therapy within 2 days of age (OR: 13.6; 95% CI: 3.7-50.2) and receiving nasal continuous positive airway pressure (n-CPAP) support at 24 hours of age (OR: 9.8; 95% CI: 2.5-38.4) independently predicted septicemia after the first day of life.

CONCLUSIONS

Whereas vertically transmitted septicemia was dominated by Gram-negative bacteria, with predictors being exclusively of maternal origin, EOS was dominated by typically nosocomial flora, with n-CPAP treatment at 24 hours of age being a powerful predictor. Early n-CPAP treatment, as opposed to mechanical ventilation, as a powerful predictor of septicemia in the early neonatal period, even with adjustment for early systemic antibiotic treatment, is a new observation among extremely premature infants that warrants additional study.

Late-onset septicemia in a Norwegian national cohort of extremely premature infants receiving very early full human milk feeding

OBJECTIVES

To investigate the occurrence of and risk factors for late-onset septicemia (LOS) in a national cohort of extremely premature infants who received very early full human milk feeding.

METHODS

A prospective study of all infants born in Norway in 1999 and 2000 with gestational age of <28 weeks or birth weight of <1000 g was performed. Extensive clinical information, including data on feeding practices and episodes of septicemia, was collected on predefined forms. LOS was defined as growth of bacteria or fungi in blood cultures in conjunction with clinical symptoms consistent with systemic infection occurring after day 6 of life. Cox regression models, including models allowing for time-dependent covariates, were applied in the analysis of LOS.

RESULTS

Of 464 eligible infants, 462 (99.6%) were enrolled and 405 (87.7%) survived until day 7. LOS was diagnosed for 80 (19.7%). The predominant pathogens were coagulase-negative staphylococci, followed by Candida spp. Case fatality rates associated with septicemia were 10% in general and 43% for Candida spp septicemia. Necrotizing enterocolitis or bowel perforation was diagnosed for 19 infants (4%). Enteral feeding with human milk was initiated within the third day for 98% of patients, and 92% were receiving full enteral feeding (FEF) with human milk within the third week. Both high Clinical Risk Index for Babies scores and an umbilical venous catheter in situ at 7 days of age significantly predicted LOS. However, the overall most influential risk factor for LOS was the number of days without establishment of FEF with human milk, with an adjusted relative risk of 3.7 (2.0-6.9) for LOS if FEF was not established within the second week of life.

CONCLUSIONS

The incidence and case fatality rate of septicemia for this cohort of extremely preterm infants were lower than values in comparable studies. The main difference, compared with other studies, was the feeding practice, and the data suggest that very early FEF with human milk significantly reduces the risk of LOS among extremely premature infants.

Vancomycin

This review describes the use of vancomycin in neonates over the last three decades. Given the relation of late-onset neonatal septicaemia to outcome and the increase in coagulase-negative staphylococcal infection as causative organism, vancomycin remains an important antibacterial in the neonatal intensive care unit. The pharmacokinetic behaviour of vancomycin in neonates can be adequately described by a one- or two-compartment model and is mainly determined by postconceptional age and renal function. In neonates, a patent ductus arteriosus as well as treatment with indomethacin or extracorporeal membrane oxygenation (ECMO) leads to an increase in volume of distribution and a decrease in clearance. Microbiological studies in vitro have shown that an increase in vancomycin concentrations above the minimum inhibitory concentration does not result in more effective killing. The microbiological and clinical efficacy of vancomycin in neonates has only been studied explicitly in a restricted number of patients. There are no definitive data relating serum concentrations to effect in this patient group. Vancomycin-related nephrotoxicity and ototoxicity in neonates is rare, and no clear relation to serum concentrations has been demonstrated. Based on the pharmacokinetic profile of vancomycin in neonates, several administration regimens have been constructed. Recent guidelines have suggested that dosage can be independent of gestational age or postconceptional age in neonates without renal failure. In patients with renal failure, therapy can be adequately tailored by using a regimen based on serum creatinine. The usefulness of routine monitoring of peak serum concentrations is doubtful based on the current literature. Recent research demonstrates a shift towards taking only routine trough serum concentrations in order to optimise efficacy. Patients with renal failure and other special subpopulations, such as patients exposed to ECMO or indomethacin, need to be monitored more closely.

Phenotypic and genotypic characterisation of blood isolates of coagulase-negative staphylococci in the newborn

Coagulase-negative staphylococci (CNS) are the leading cause of late-onset sepsis in newborns (>72 h of age). Our aim was to determine whether phenotypic and/or genotypic differences existed between blood isolates of CNS regarded as inducers of sepsis or as contaminants. Ninety-seven bloodisolates of CNS recovered from newborns at the neonatal intensive care unit, Orebro, Sweden in 1983-1997 were analysed. Twenty-nine of them (30%) were classified as sepsis isolates and 68 (70%) as contaminants. The most prevalent species was Staphylococcus epidermidis (n=59). Staphylococcus haemolyticus (n=16) was most often isolated from newborns with the lowest gestational age and birth weight. Biochemical typing using the Phene Plate system (PhP) and genotyping using pulsed-field gel electrophoresis (PFGE) showed that the S. epidermidis isolates regarded as inducers of sepsis (n=16) were more homogeneous than isolates considered contaminants (n=37). One main genotypic group, representing seven (44%) isolates, was identified among the sepsis isolates. Phenotypically the S. epidermidis sepsis isolates comprised three major clusters. In contrast, among the S. epidermidis contaminants, eight genotypic groups and two phenotypic clusters were identified. The dominating genotypic group among the sepsis isolates of S. epidermidis may represent strains with higher invasive capacity.

The ica operon and biofilm production in coagulase-negative Staphylococci associated with carriage and disease in a neonatal intensive care unit

Coagulase-negative staphylococci (CoNS) are a major cause of sepsis in the neonatal intensive care unit (NICU). We evaluated the hypothesis that the ica operon and biofilm production are associated with CoNS disease in this setting. CoNS associated with bacteremia or blood culture contamination and from the skin of infants with CoNS bacteremia or healthy controls were obtained during a prospective case-control study on a busy NICU. A total of 180 strains were identified, of which 122 (68%) were Staphylococcus epidermidis and the remainder were S. capitis (n = 29), S. haemolyticus (n = 11), S. hominis (n = 9), S. warneri (n = 8), and S. auricularis (n = 1). The presence of the genes icaA, icaB, icaC, and icaD was determined by PCR, and biofilm production was examined using qualitative (Congo red agar [CRA]) and quantitative (microtiter plate) techniques. There were no significant differences in the presence of the ica operon or CRA positivity among the four groups of strains. However, quantitative biofilm production was significantly greater in strains isolated from either the blood or the skin of neonates with S. epidermidis bacteremia. We conclude that the quantity of biofilm produced may be associated with the ability to cause CoNS infection. This conclusion suggests that the regulation of biofilm expression may play a central role in the disease process.

Genetic population structure of coagulase-negative staphylococci associated with carriage and disease in preterm infants

Coagulase-negative staphylococci (CoNS) are a leading cause of sepsis in the neonatal intensive care unit (NICU) setting. To evaluate the hypothesis that isolates of CoNS associated with disease belong to hypervirulent clones, as opposed to being drawn randomly from the neonatal unit carriage flora, we conducted a prospective, case-controlled study in a busy NICU. Using pulsed-field gel electrophoresis (PFGE), we compared the population structures of CoNS isolates associated with bacteremia with isolates from the skin of healthy and infected neonates and with blood culture contaminants. Endemic clones of CoNS were identified, but there was no difference in the distribution of the 6 species or 73 PFGE types between the carriage and disease isolate groups; this suggests that hypervirulent clones with an enhanced ability to cause disease were not present in this NICU setting.

Nosocomial coagulase negative staphylococcal (CoNS) catheter-related sepsis in preterm infants: definition, diagnosis, prophylaxis, and prevention

Nosocomial infections with coagulase negative staphylococcus (CoNS) are a frequent and significant cause of morbidity in the preterm infant. Infections diagnosed after the first 72 hours of life are arbitrarily deemed to be "nosocomial." There are many difficulties encountered in efforts to evaluate and compare nosocomial sepsis in the NICU. An issue of primary concern is the lack of uniformity in the definition of sepsis in the NICU. Based on the frequency of positive blood cultures in infants less than 1000 g, it appears reasonable to evaluate methods for the prevention of nosocomial sepsis. These include prophylactic antibiotic administration, antiseptic impregnated catheters, and the use of an antibiotic lock technique.

Fluconazole for prophylaxis against candidal rectal colonization in the very low birth weight infant

BACKGROUND

Candidal infections are an important cause of morbidity and mortality in the very low birth weight (VLBW) infant. Current intervention focuses on treatment once candidal septicemia is either suspected or diagnosed. Studies have suggested that colonization with candidal species is an important risk factor for subsequent infection.

OBJECTIVE

To determine whether prophylactic fluconazole for the first 28 days of life results in a decreased incidence of candidal colonization in the VLBW infant.

RESEARCH DESIGN

Prospective, randomized, controlled, intention-to-treat design comparing prophylaxis with fluconazole versus placebo for the first 28 days of life.

SETTING

A tertiary level intensive care nursery in a major teaching hospital in Charleston, South Carolina.

PATIENTS

One hundred three infants with a birth weight of <1500 g, either inborn or outborn, who were admitted to the intensive care nursery between January 1998 and February 1999.

METHODS

Infants were enrolled within 72 hours of life with rectal cultures performed on the day of randomization (DOR), as well as day of life (DOL) 7, 14, and 28. Those infants with a birth weight of <1250 g had additional cultures on DOL 35, 49, and 56. Cultures were plated on selective media for isolation of candidal organisms. Infants were randomized to receive either fluconazole (6 mg/kg) or placebo on the DOR. Subsequent doses were given every 72 hours until DOL 7 and then every 24 hours until DOL 28. Medication was given either intravenously or by feeding tube once the infant had been gavage feeding for a 48-hour period without feeding intolerance. Aspartate aminotransferase and alanine aminotransferase levels were obtained on DOR and DOL 7, 14, and 28 to assess for fluconazole toxicity. The minimal inhibitory concentration to fluconazole was determined for all positive cultures to assess the development of resistance.

RESULTS

The infants who received fluconazole (n = 53) and placebo (n = 50) had no statistical difference in the major risk factors known to increase the chances of candidal septicemia in the VLBW infant. Rectal colonization by candidal species was detected in 8 of the 53 fluconazole-treated patients (15.1%) and in 23 of the 50 infants treated with placebo (46%). Fluconazole significantly reduced rectal colonization from DOL 14 through DOL 56 in all infants with a birth weight of <1250 g, and from DOL 14 through DOL 56 in all infants with a birth weight of 1250 to 1500 g. Alanine aminotransferase levels were higher in the fluconazole versus the placebo-treated group on DOL 14 (18.1 IU/L vs 15 IU/L), but no clinically significant abnormalities were observed. Candida albicans was the most common species isolated. There was no increase in species of Candida noted for their intrinsic resistance to fluconazole, and there was no statistically significant difference in the minimal inhibitory concentrations to fluconazole for all C albicans isolates in either group at any period.

CONCLUSION

Prophylactic administration of fluconazole to the VLBW infant for the first 28 days of life is safe and results in a decreased risk of rectal colonization by candidal species. Larger studies to determine the effect of prophylaxis on candidal septicemia and development of resistance in such a selective high-risk group are warranted before initiation of routine prophylaxis.fluconazole, very low birth weight infant, prophylaxis, candidal sepsis, sensitivities to fluconazole.

Increase of Enterobacter in neonatal sepsis: a twenty-two-year study

BACKGROUND

Data on the incidence of Enterobacter infections in neonates over prolonged periods of time are scant. We determined the epidemiology of Enterobacter sepsis and/or meningitis and the trends of infection in a neonatal unit.

METHODS

Retrospective review of sepsis and/or meningitis in inborn neonates admitted to Son Dureta University Hospital during a 22-year period. Molecular study by ribotyping of the Enterobacter strains isolated from 1995 to 1997.

RESULTS

There were 513 cases of culture-proved sepsis and/or meningitis in neonates. In late onset infections Klebsiella pneumoniae and Staphylococcus epidermidis were the most frequent isolates in the period 1977 through 1991. Enterobacter was the most common isolate in the period 1992 through 1998. During this latter period Candida infections also increased, and the resistance rate of Enterobacter to cefotaxime was higher (59.2%). Decrease in early onset infections and increase in late onsets (4.6/1,000 live births) were observed in the second period. From 1977 to 1998, 45 episodes of sepsis and/or meningitis by Enterobacter species were identified in 44 patients (8.7% of all neonatal bacteremias). Three patients with Enterobacter bacteremia died (6.6%, 0.03/1,000 live births). During 1995 through 1997 5 different clones causing sepsis were identified and 3 were predominant. In 1997 there was an outbreak of Enterobacter disease. After cleaning, cohort nursing and hygiene reinforcement, Enterobacter was not isolated in the next 2 years. No change in the antibiotic policy was made.

CONCLUSIONS

We observed a resurgence of Enterobacter infections in our neonatal intensive care unit. The sudden disappearance of this microorganism after reinforcement of hygienic measures, without withdrawing cefotaxime, confirms the importance of patient-to-patient transmission of this nosocomial infection. Further studies are needed to establish the role of antibiotics in the emergence of microorganisms in neonatal intensive care units.

Antibiotic susceptibility of blood culture isolates after nearly two decades with netilmicin and ampicillin in neonatal septicaemia

The aim of the study was to investigate the in vitro antibiotic susceptibility of blood culture isolates after almost 20 years with ampicillin and methicillin as empirical treatment for neonatal septicaemia. All blood culture isolates and their antibiograms obtained in a single tertiary neonatal intensive care unit from 1 January 1989 to 31 December 1994 were reviewed. Two hundred and six blood cultures from 181 infants containing 223 bacterial and 11 fungal isolates were identified during 4416 admissions. Fifteen (6.7%) of the bacterial isolates were resistant to ampicillin and netilmicin. Fourteen per cent of the staphylococcal spp. were susceptible to penicillin while more than 90% were susceptible to netilmicin. The coagulase-negative staphylococci (CONS) were resistant to netilmicin, methicillin and gentamicin in 12%, 49% and 65%, respectively. Eighty-nine per cent of the methicillin-resistant CONS were susceptible to netilmicin as opposed to 17% to gentamicin (p<0.001). Except for one strain of Acinetobacter sp., all Gram-negative bacteria were susceptible to netilmicin. Our data show that the ampicillin-netilmicin combination still provides a high in vitro coverage (93%) against bacteria identified in blood cultures from newborns in our unit. Netilmicin has a significantly better in vitro effectiveness against CONS than gentamicin.