A comparison of ceftazidime and aminoglycoside based regimens as empirical treatment in 1316 cases of suspected sepsis in the newborn. European Society for Paediatric Infectious Diseases--Neonatal Sepsis Study Group

Neonatal sepsis: a systematic review of core outcomes from randomised clinical trials

BACKGROUND

The lack of a consensus definition of neonatal sepsis and a core outcome set (COS) proves a substantial impediment to research that influences policy and practice relevant to key stakeholders, patients and parents.

METHODS

A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In the included studies, the described outcomes were extracted in accordance with the provisions of the Core Outcome Measures in Effectiveness Trials (COMET) handbook and registered.

RESULTS

Among 884 abstracts identified, 90 randomised controlled trials (RCTs) were included in this review. Only 30 manuscripts explicitly stated the primary and/or secondary outcomes. A total of 88 distinct outcomes were recorded across all 90 studies included. These were then assigned to seven different domains in line with the taxonomy for classification proposed by the COMET initiative. The most frequently reported outcome was survival with 74% (n = 67) of the studies reporting an outcome within this domain.

CONCLUSIONS

This systematic review constitutes one of the initial phases in the protocol for developing a COS in neonatal sepsis. The paucity of standardised outcome reporting in neonatal sepsis hinders comparison and synthesis of data. The final phase will involve a Delphi Survey to generate a COS in neonatal sepsis by consensus recommendation.

IMPACT

This systematic review identified a wide variation of outcomes reported among published RCTs on the management of neonatal sepsis. The paucity of standardised outcome reporting hinders comparison and synthesis of data and future meta-analyses with conclusive recommendations on the management of neonatal sepsis are unlikely. The final phase will involve a Delphi Survey to determine a COS by consensus recommendation with input from all relevant stakeholders.

Antibiotic regimens for early-onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Possibly due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units. The last Cochrane Review was updated in 2004. Given the clinical importance, an updated systematic review assessing the effects of different antibiotic regimens for early-onset neonatal sepsis is needed.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for early-onset neonatal sepsis.

SEARCH METHODS

We searched the following electronic databases: CENTRAL (2020, Issue 8); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs comparing different antibiotic regimens for early-onset neonatal sepsis. We included participants from birth to 72 hours of life at randomisation.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included five RCTs (865 participants). All trials were at high risk of bias. The certainty of the evidence according to GRADE was very low. The included trials assessed five different comparisons of antibiotics. We did not conduct any meta-analyses due to lack of relevant data. Of the five included trials one trial compared ampicillin plus gentamicin with benzylpenicillin plus gentamicin; one trial compared piperacillin plus tazobactam with amikacin; one trial compared ticarcillin plus clavulanic acid with piperacillin plus gentamicin; one trial compared piperacillin with ampicillin plus amikacin; and one trial compared ceftazidime with benzylpenicillin plus gentamicin. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to support any antibiotic regimen being superior to another. Large RCTs assessing different antibiotic regimens in early-onset neonatal sepsis with low risk of bias are warranted.

Antibiotic regimens for late-onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units, and observational studies in high-income countries suggest that 83% to 94% of newborns treated with antibiotics for suspected sepsis have negative blood cultures. The last Cochrane Review was updated in 2005. There is a need for an updated systematic review assessing the effects of different antibiotic regimens for late-onset neonatal sepsis.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for late-onset neonatal sepsis.

SEARCH METHODS

We searched the following electronic databases: CENTRAL (2021, Issue 3); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs comparing different antibiotic regimens for late-onset neonatal sepsis. We included participants older than 72 hours of life at randomisation, suspected or diagnosed with neonatal sepsis, meningitis, osteomyelitis, endocarditis, or necrotising enterocolitis. We excluded trials that assessed treatment of fungal infections.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included five RCTs (580 participants). All trials were at high risk of bias, and had very low-certainty evidence. The five included trials assessed five different comparisons of antibiotics. We did not conduct a meta-analysis due to lack of relevant data. Of the five included trials one trial compared cefazolin plus amikacin with vancomycin plus amikacin; one trial compared ticarcillin plus clavulanic acid with flucloxacillin plus gentamicin; one trial compared cloxacillin plus amikacin with cefotaxime plus gentamicin; one trial compared meropenem with standard care (ampicillin plus gentamicin or cefotaxime plus gentamicin); and one trial compared vancomycin plus gentamicin with vancomycin plus aztreonam. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to support any antibiotic regimen being superior to another. RCTs assessing different antibiotic regimens in late-onset neonatal sepsis with low risks of bias are warranted.

Population pharmacokinetics-pharmacodynamics of ceftazidime in neonates and young infants: Dosing optimization for neonatal sepsis

Ceftazidime is a third-generation cephalosporin with high activity against many pathogens. But the ambiguity and diversity of the dosing regimens in neonates and young infants impair access to effective treatment. Thus, we conducted a population pharmacokinetic study of ceftazidime in this vulnerable population and recommended a model-based dosage regimen to optimize sepsis therapy. Totally 146 neonates and young infants (gestational age (GA): 36-43.4 weeks, postnatal age (PNA): 1-81 days, current weight (CW): 900-4500 g) were enrolled based on inclusion and exclusion criteria. Ceftazidime bloods samples (203) were obtained using the opportunistic sampling strategy and determined by the high-performance liquid chromatography. The population pharmacokinetic-pharmacodynamic analysis was conducted by nonlinear mixed effects model (NONMEM). A one-compartment model with first-order elimination best described the pharmacokinetic data. Covariate analysis showed the significance of GA, PNA, and CW on developmental pharmacokinetics. Monte Carlo simulation was performed based on above covariates and minimum inhibitory concentration (MIC). In the newborns with PNA ≤ 3 days (MIC=8 mg/L), the dose regimen was 25 mg/kg twice daily (BID). For the newborns with PNA > 3 days (MIC=16 mg/L), the optimal dose was 30 mg/kg three times daily (TID) for those with GA ≤ 37 weeks and 40 mg/kg TID for those with GA > 37 weeks. Overall, on the basis of the developmental population pharmacokinetic-pharmacodynamic analysis covering the whole range of neonates and young infants, the evidence-based ceftazidime dosage regimens were proposed to optimize neonatal early-onset and late-onset sepsis therapy.

Characterization of the Clinical Outcomes With Cefepime in a Neonatal Intensive Care Unit: A Retrospective Cohort Study

OBJECTIVES

The objective of this study was to characterize clinical outcomes when cefepime was used in a neonatal intensive care population.

METHODS

Data were extracted from the medical records of all full-term (40 weeks gestational age) patients up to 2 months of age and preterm patients up to 48 weeks postmenstrual age admitted to the neonatal intensive care unit (NICU) at a freestanding children's hospital between January 1, 2010, and December 31, 2013, who received at least 48 hours of cefepime. The primary outcome measure was a positive clinical response as defined by a normalization of white blood cell count and/or culture clearance.

RESULTS

Final analysis included 74 patients. Clinical response was evaluable in 43.2% (32 of 74) of courses. Of these, positive clinical response was observed in 81.3% (26 of 32). Overall patient mortality was 16.2% (12 of 74). Adverse effects (AEs) occurred in 14.9% (11 of 74) of courses.

CONCLUSIONS

Cefepime can be used safely with reasonable clinical response in a NICU population, but additional studies are needed to further determine cefepime-associated clinical outcomes.

Antibiotic exposure in neonates and early adverse outcomes: a systematic review and meta-analysis

Objectives

To systematically review and meta-analyse the relationship between antibiotic exposure in neonates and the following early adverse outcomes: necrotizing enterocolitis (NEC), invasive fungal infections (IFIs) and/or death.

Methods

Data sources were PubMed, Embase, Medline and the Cochrane Database (to December 2016), supplemented by manual searches of reference lists. Randomized controlled trials (RCTs) and observational studies were included if they provided data on different categories of antibiotic exposures (yes versus no, long versus short duration, and/or broad- versus narrow-spectrum regimens) and the risk of developing NEC, IFI and/or death in the neonatal period. Two reviewers extracted data and evaluated the risk of bias using the Cochrane Handbook, adapted to include observational studies. When appropriate, meta-analyses were conducted using the random-effect model.

Results

We identified 9 RCTs and 38 observational studies. The quality of the majority of studies was poor to moderate. There was a significant association between prolonged antibiotic exposure and an increased risk of NEC in five observational studies (5003 participants) and/or risk of death in five observational studies (13 534 participants). Eleven of 15 studies with data on broad- versus narrow-spectrum regimens reported an increased risk of IFI after broad-spectrum antibiotic exposure, in particular with third-generation cephalosporins and carbapenems. Meta-analysis was limited by few and old RCTs, insufficient sample sizes and diversity of antibiotic exposure and outcomes reported.

Conclusions

Prolonged antibiotic exposure in uninfected preterm infants is associated with an increased risk of NEC and/or death, and broad-spectrum antibiotic exposure is associated with an increased risk of IFI.

Epidemiology of bacteremia in young hospitalized infants in Vientiane, Laos, 2000-2011

As data about the causes of neonatal sepsis in low-income countries are inadequate, we reviewed the etiology and antibiotic susceptibilities of bacteremia in young infants in Laos. As Staphylococcus aureus is the leading cause of bacteremia in Lao infants, we also examined risk factors for this infection, in particular the local practice of warming mothers during the first weeks postpartum with hot coals under their beds (hot beds). Clinical and laboratory data regarding infants aged 0-60 days evaluated for sepsis within 72 h of admission to Mahosot Hospital in Vientiane, Laos, were reviewed, and 85 of 1438 (5.9%) infants' blood cultures grew a clinically significant organism. Most common were S. aureus, Escherichia coli and Klebsiella pneumoniae. Whereas no methicillin-resistant S. aureus was found, only 18% of E. coli isolates were susceptible to ampicillin. A history of sleeping on a hot bed with mother was associated with S. aureus bacteremia (odds ratio 4.8; 95% confidence interval 1.2-19.0).

Beta lactam antibiotic monotherapy versus beta lactam-aminoglycoside antibiotic combination therapy for sepsis

BACKGROUND

Optimal antibiotic treatment for sepsis is imperative. Combining a beta lactam antibiotic with an aminoglycoside antibiotic may provide certain advantages over beta lactam monotherapy.

OBJECTIVES

Our objectives were to compare beta lactam monotherapy versus beta lactam-aminoglycoside combination therapy in patients with sepsis and to estimate the rate of adverse effects with each treatment regimen, including the development of bacterial resistance to antibiotics.

SEARCH METHODS

In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11); MEDLINE (1966 to 4 November 2013); EMBASE (1980 to November 2013); LILACS (1982 to November 2013); and conference proceedings of the Interscience Conference of Antimicrobial Agents and Chemotherapy (1995 to 2013). We scanned citations of all identified studies and contacted all corresponding authors. In our previous review, we searched the databases to July 2004.

SELECTION CRITERIA

We included randomized and quasi-randomized trials comparing any beta lactam monotherapy versus any combination of a beta lactam with an aminoglycoside for sepsis.

DATA COLLECTION AND ANALYSIS

The primary outcome was all-cause mortality. Secondary outcomes included treatment failure, superinfections and adverse events. Two review authors independently collected data. We pooled risk ratios (RRs) with 95% confidence intervals (CIs) using the fixed-effect model. We extracted outcomes by intention-to-treat analysis whenever possible.

MAIN RESULTS

We included 69 trials that randomly assigned 7863 participants. Twenty-two trials compared the same beta lactam in both study arms, while the remaining trials compared different beta lactams using a broader-spectrum beta lactam in the monotherapy arm. In trials comparing the same beta lactam, we observed no difference between study groups with regard to all-cause mortality (RR 0.97, 95% CI 0.73 to 1.30) and clinical failure (RR 1.11, 95% CI 0.95 to 1.29). In studies comparing different beta lactams, we observed a trend for benefit with monotherapy for all-cause mortality (RR 0.85, 95% CI 0.71 to 1.01) and a significant advantage for clinical failure (RR 0.75, 95% CI 0.67 to 0.84). No significant disparities emerged from subgroup and sensitivity analyses, including assessment of participants with Gram-negative infection. The subgroup of Pseudomonas aeruginosa infections was underpowered to examine effects. Results for mortality were classified as low quality of evidence mainly as the result of imprecision. Results for failure were classified as very low quality of evidence because of indirectness of the outcome and possible detection bias in non-blinded trials. We detected no differences in the rate of development of resistance. Nephrotoxicity was significantly less frequent with monotherapy (RR 0.30, 95% CI 0.23 to 0.39). We found no heterogeneity for all these comparisons.We included a small subset of studies addressing participants with Gram-positive infection, mainly endocarditis. We identified no difference between monotherapy and combination therapy in these studies.

AUTHORS' CONCLUSIONS

The addition of an aminoglycoside to beta lactams for sepsis should be discouraged. All-cause mortality rates are unchanged. Combination treatment carries a significant risk of nephrotoxicity.

Clinical trials in neonatal sepsis

Antibiotic licensing studies remain a problem in neonates. The classical adult clinical syndrome-based licensing studies do not apply to neonates, where sepsis is the most common infection. The main obstacle to conducting neonatal antibiotic trials is a lack of consensus on the definition of neonatal sepsis itself and the selection of appropriate endpoints. This article describes the difficulties of the clinical and laboratory definitions of neonatal sepsis and reviews the varying designs of previous neonatal sepsis trials. The optimal design of future trials of new antibiotics will need to be based on pharmacokinetic/pharmacodynamic parameters, combined with adequately powered clinical studies to determine safety and efficacy.

Antibiotics and Antifungals in Neonatal Intensive Care Units: A Review

The incidence of infections is higher in the neonatal period than at any time of life. The basic treatment of infants with infection has not changed substantially over the last years. Antibiotics (with or without supportive care) are one of the most valuable resources in managing sick newborn babies. Early-onset (ascending or transplacental) or late-onset (hospital acquired) infections present different chronology, epidemiology, physiology and outcome. Some classes of antibiotics are frequently used in the neonatal period: penicillins, cephalosporins, aminoglycosides, glycopeptides, monobactams, carbapenems. Other classes of antibiotics (chloramphenicol, cotrimoxazole, macrolides, clindamycin, rifampicin and metronidazole) are rarely used. Due to emergence of resistant bacterial strains in Neonatal Intensive Care Units (NICU), other classes of antibiotics such as quinolones and linezolid will probably increase their therapeutic role in the future. Although new formulations have been developed for treatment of fungal infections in infants, amphotericin B remains first-line treatment for systemic Candida infection. Prophylactic antibiotic therapy is almost always undesirable. Challenges from pathogens and antibiotic resistance in the NICU may warrant modification of traditional antibiotic regimens. Knowledge of local flora and practical application of different antibiotic characteristics are key to an effective and safe utilization of antibiotics and antifungals in critical newborns admitted to the NICU, and especially in very low birth weight infants.

Beta lactam antibiotic monotherapy versus beta lactam-aminoglycoside antibiotic combination therapy for sepsis

BACKGROUND

Optimal antibiotic treatment for sepsis is imperative. Combining a beta-lactam antibiotic with an aminoglycoside antibiotic may have certain advantages over beta-lactam monotherapy.

OBJECTIVES

We compared clinical outcomes for beta lactam-aminoglycoside combination therapy versus beta lactam monotherapy for sepsis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, Issue 3, 2004); MEDLINE (1966 to July 2004); EMBASE (1980 to March 2003); LILACS (1982 to July 2004); and conference proceedings of the Interscience Conference of Antimicrobial Agents and Chemotherapy (1995 to 2003). We scanned citations of all identified studies and contacted all corresponding authors.

SELECTION CRITERIA

We included randomized and quasi-randomized trials comparing any beta-lactam monotherapy to any combination of one beta-lactam and one aminoglycoside for sepsis.

DATA COLLECTION AND ANALYSIS

The primary outcome was all-cause fatality. Secondary outcomes included treatment failure, superinfections, colonization, and adverse events. Two authors independently collected data. We pooled relative risks (RR) with their 95% confidence intervals (CI) using the fixed effect model. We extracted outcomes by intention-to-treat analysis whenever possible.

MAIN RESULTS

We included 64 trials, randomizing 7586 patients. Twenty trials compared the same beta-lactam in both study arms, while the remaining compared different beta-lactams using a broader spectrum beta-lactam in the monotherapy arm. In studies comparing the same beta-lactam, we observed no difference between study groups with regard to all-cause fatality, RR 1.01 (95% CI 0.75-1.35) and clinical failure, RR 1.11 (95% CI 0.95-1.29). In studies comparing different beta-lactams, we observed an advantage to monotherapy: all cause fatality RR 0.85 (95% CI 0.71-1.01), clinical failure RR 0.77 (95% CI 0.69-0.86). No significant disparities emerged from subgroup and sensitivity analyses, including the assessment of patients with Gram-negative and Pseudomonas aeruginosa infections. We detected no differences in the rate of resistance development. Adverse events rates did not differ significantly between the study groups overall, although nephrotoxicity was significantly more frequent with combination therapy, RR 0.30 (95% CI 0.23-0.39). We found no heterogeneity for all comparisons. We included a small subset of studies addressing patients with Gram-positive infections, mainly endocarditis. We identified no difference between monotherapy and combination therapy in these studies.

AUTHORS' CONCLUSIONS

The addition of an aminoglycoside to beta-lactams for sepsis should be discouraged. All-cause fatality rates are unchanged. Combination treatment carries a significant risk of nephrotoxicity.

Antibiotic regimens for suspected late onset sepsis in newborn infants

BACKGROUND

Late onset neonatal sepsis (systemic infection after 48 hours of age) continues to be a significant cause of morbidity and mortality. Early treatment with antibiotics is essential as infants can deteriorate rapidly. It is not clear which antibiotic regimen is most suitable for initial treatment of suspected late onset sepsis.

OBJECTIVES

To compare the effectiveness and adverse effects of different antibiotic regimens for treatment of suspected late onset sepsis in newborn infants.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This includes electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2004), MEDLINE (1966 - Dec 2004), EMBASE (1980 - Dec 2004) and CINAHL (1982 - Dec 2004), electronic abstracts of Pediatric Academic Society meetings (1996 - Dec 2004) and previous reviews including cross references (all articles referenced).

SELECTION CRITERIA

Randomised and quasi randomised controlled trials comparing different initial antibiotic regimens in neonates with suspected late onset sepsis were evaluated.

DATA COLLECTION AND ANALYSIS

Both reviewer authors screened abstracts and papers against the inclusion criteria, appraised the quality of and extracted data from papers. For dichotomous outcomes, treatment effect was expressed as relative risk and risk difference with 95% confidence intervals. NNT was calculated for outcomes for which there was a statistically significant reduction in risk difference.

MAIN RESULTS

Thirteen studies were identified as possibly eligible for inclusion. The majority of studies were excluded as they did not separate data for early and late onset infection. Two studies are still awaiting assessment. Only one small study, in 24 neonates, was included in this review. It compared beta-lactam therapy with a combination of beta lactam plus aminoglycoside. The study did not meet our prespecified criteria for good methodological quality. In babies with suspected infection there was no significant difference in mortality (RR 0.17, 95% CI 0.01 to 3.23) or treatment failure (RR 0.17, 95% CI 0.01 to 3.23). Antibiotic resistance was assessed and there were no cases in either group.

AUTHORS' CONCLUSIONS

There is inadequate evidence from randomised trials in favour of any particular antibiotic regimen for the treatment of suspected late onset neonatal sepsis. The available evidence is not of high quality. Although suspected sepsis and antibiotic use is common, quality research is required to specifically address both narrow and broad spectrum antibiotic use for late onset neonatal sepsis. Future research also needs to assess cost effectiveness and the impact of antibiotics in different settings such as developed or developing countries and lower gestational age groups.

New dosing strategies for antibacterial agents in the neonate

Dosing of antibiotics in neonates requires finding a delicate balance between maximal efficacy and minimal toxicity. There is a lack of data on efficacy of currently used antibiotics in neonates, and rational dosing therefore needs to be based on gestational- and postnatal-age-dependent pharmacokinetics in combination with surrogate markers. These surrogate markers are: (i) the area-under-the serum concentration time curve to minimum inhibitory concentration ratio (AUC/MIC); (ii) peak concentration to MIC ratio (Cmax/MIC); and (iii) the time the concentration remains above the MIC (T>MIC). Whereas the efficacy of beta-lactam antibiotics (including carbapenems) depends on T>MIC, the efficacy of most other antimicrobials (including aminoglycosides and fluoroquinolones) is related to AUC/MIC and Cmax/MIC. Most modern dosing regimens are adequate when these concentration effect relationships are taken into account. Dosing adjustments in neonates are suggested, based on these relationships. Several antimicrobial combinations for treatment of meningitis and necrotizing enterocolitis exist. Empiric treatment should be based on efficacy, concerns about resistance as well as information from institutional microbiological surveillance.

Antibiotic regimens for suspected early neonatal sepsis

BACKGROUND

Early acquired infection may cause severe illness or death in the neonatal period. Prompt treatment with antibiotics has shown to reduce mortality. It is not clear which antibiotic regimen is suitable for treatment of presumed early neonatal sepsis.

OBJECTIVES

To compare effectiveness and adverse effects of antibiotic regimens for treatment of presumed early neonatal sepsis.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2003), MEDLINE (1966 to August 2003), EMBASE (1980 to September 2003) and ZETOC (1993 to August 2003) databases were searched for possible studies. Pharmaceutical companies were contacted for any unpublished data.

SELECTION CRITERIA

Randomised and quasi-randomised controlled studies comparing antibiotic regimens for the treatment of early neonatal sepsis (both monotherapies and combination therapies).

DATA COLLECTION AND ANALYSIS

Both reviewers screened abstracts and full reports against the inclusion criteria, appraised the quality of and extracted data from papers. For dichotomous outcomes, treatment effect was expressed as relative risk with 95% confidence interval. Meta-analysis was performed using a fixed effect model.

MAIN RESULTS

Two small studies had compared monotherapy with combination therapy. There was no significant difference in mortality, treatment failure or bacteriological resistance.

REVIEWERS' CONCLUSIONS

There is no evidence from randomised trials to suggest that any antibiotic regimen may be better than any other in the treatment of presumed early neonatal sepsis. More studies are needed to resolve this issue.

Non-nutritive sucking in sick preterm infants

BACKGROUND

Non-nutritive sucking (NNS) by the newborn infant is a fundamental behaviour and is one of the first coordinated muscular activities in the fetus.

AIMS

Our objective is to study the NNS pattern in prematurely born infants, who had various conditions commonly associated with immaturity.

METHOD

A specially designed computer-based method that analyses and quantifies components of the NNS pattern was used.

SUBJECTS

The pattern of 51 clinically stable prematurely born infants (gestational ages 26-35 weeks) making a total of 206 observations were analysed and findings were compared with those obtained from 58, healthy preterm infants.

RESULTS

The rhythmic NNS pattern of alternating sucking and pauses was elicited in all examined infants, the earliest at post-menstrual age (PMA) 26 weeks. The role of PMA, the dominant predictor for several sucking variables seen in the control group, became diminished for the infants with risk factors but changes were otherwise similar. The infants' sucking activity and sucking frequency increased and the variability of the pattern declined with increased PMA and weight. Follow-up of a subgroup of infants revealed fewer sucking bursts per minute, slower sucking frequency and a greater variability of the frequency and amplitudes in those infants who developed sequelae.

CONCLUSIONS

It would, thus, appear that the NNS pre-programmed rhythm generator, primarily modulated by maturation in healthy preterm infants, becomes affected by known risk associated events and in infants who later develop sequelae. Quantification of the NNS pattern in preterm infants may be a valuable future component of their evaluation.

Preterm infants with low immunoglobulin G levels have increased risk of neonatal sepsis but do not benefit from prophylactic immunoglobulin G

OBJECTIVE

In a prospective, randomized, placebo-controlled, multicenter study, we evaluated the prevention of neonatal infections with intravenous immunoglobulin G (IVIgG) prophylaxis for preterm infants (gestational age <33 weeks) with umbilical cord blood IgG levels < or =4 g/L.

STUDY DESIGN

Intravenous IgG or placebo (albumin), 1 g/kg body weight, was given on days 0, 3, 7, 14, and 21 to 81 infants with umbilical cord blood IgG levels < or =4 g/L: (1) IVIgG group, n = 40, mean (SD) gestational age 27.5 (2.2) weeks and birth weight 1.06 (0.39) kg; (2) placebo group, n = 41, mean (SD) gestational age 27.7 (2.5) weeks and birth weight 1.13 (0.38) kg. Infants with umbilical cord blood IgG levels >4 g/L (n = 238) served as a separate comparison group. Neonatal infections according to European Society of Pediatric Infectious Disease criteria were monitored until 28 days of life.

RESULTS

Infants with IgG levels < or =4 g/L at birth who received IVIgG had no significant reduction in infectious episodes or mortality rate when compared with those given placebo. However, infants with a serum concentration of IgG >4 g/L at birth had significantly fewer infectious episodes (culture-proven sepsis) than infants with low serum concentrations of IgG (< or =4 g/L) when compared at the same gestational ages (26 to 29 weeks, P <.003).

CONCLUSIONS

Prophylactic immunotherapy with IVIgG did not improve the immune competence in preterm infants with low serum IgG concentrations at birth. We speculate that a spontaneously high serum IgG concentration at birth reflects placenta function and is an indicator of a more mature immune system capable of protecting the preterm infant against severe neonatal infections.

Non-nutritive sucking in the healthy pre-term infant

In the infant, sucking behaviour is one of the first coordinated muscular activities. It is under the control of the brainstem. In utero sucking is observed from 13 weeks' gestation. The healthy full-term newborn infant has a very stable rhythm of alternating bursts of sucking with pauses in between. The non-nutritive sucking (NNS) patterns of 58 low-risk prematurely born infants (gestational ages between 26 and 35 weeks) were studied using a specially designed computer-based method that analyses and quantifies NNS. A total of 183 observations were analysed. The typical NNS pattern with bursts of sucking activity separated by quiescent periods was recorded in all infants studied and was already present before 30 weeks of gestation. A gradual change over time of their NNS was seen. With increased maturation the sucking activity, sucking frequency, amplitude and burst duration all increased, while the variability of the sucking frequency and the duration of the intervals between bursts declined. Post-menstrual age (PMA) was the dominant predictor of this result but gender, state of activity and weight also influenced it to some extent. Girls had more sucking activity and a higher sucking frequency than boys. State of activity affected the stability of the rhythm. The weight of the infant influenced both sucking activity and duration of separate bursts.

Population pharmacokinetics of gentamicin in preterm neonates: evaluation of a once-daily dosage regimen

Population pharmacokinetic parameters of gentamicin in preterm neonates on a once-daily dosage regimen of 3.0 mg/kg given intravenously every 24 hours were established prospectively. In 34 preterm neonates with a mean gestational age of 32 +/- 4 (SD), 182 serum gentamicin levels (91 peak/trough pairs) were determined. Individual adjustments of dose or dosage interval were calculated by computer-aided Bayesian forecasting. The parameters Vd, ke, and CL for each patient were obtained by the nonparametric estimation of maximization method. The predictive power of the model was calculated and the pharmacokinetic estimates were statistically analyzed with SPSS/PC. Cluster analysis showed a division into 2 subpopulations (designated 1 and 2) on the basis of postnatal age. The mean +/- SD postnatal age of subpopulation 1 (n = 29) was 6 +/- 2 days (range 1-7) and of subpopulation 2 (n = 5) 15 +/- 4 days (range 12-24). The mean +/- SD gentamicin relative clearances of subpopulation 1 and subpopulation 2 were 0.0515 +/- 0.0128 and 0.1026 +/- 0.0102 L kg(-1) hr(-1), respectively (p < 0.05). The mean +/- SD values for Vd (Lkg(-1)) in both populations 1 and 2 were 0.6916 +/- 0.1670 and 0.7509 +/- 0.1961, respectively (not significantly different). For ke these data were 0.0744 +/- 0.0200 and 0.1366 +/- 0.0522 (p < 0.05). Statistics showed that the data for Vd and ke of subpopulation 1 were normally distributed (Vd and ke skewness 1.61 and 1.46; kurtosis 3.09 and 3.10 respectively). The model yielded a bias of -0.11 mg/L and a precision of 0.36 mg/L. It is recommended that gentamicin be started in a dosage of 3.5 mg/kg intravenously once-daily under close monitoring.

Antibiotics in neonatal infections: a review

The bacteria most commonly responsible for early-onset (materno-fetal) infections in neonates are group B streptococci, enterococci, Enterobacteriaceae and Listeria monocytogenes. Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, are the main pathogens in late-onset (nosocomial) infections, especially in high-risk patients such as those with very low birthweight, umbilical or central venous catheters or undergoing prolonged ventilation. The primary objective of the paediatrician is to identity all potential cases of bacterial disease quickly and begin antibacterial treatment immediately after the appropriate cultures have been obtained. Combination therapy is recommended for initial empirical treatment in the neonate. In early-onset infections, an effective first-line empirical therapy is ampicillin plus an aminoglycoside (duration of treatment 10 days). An alternative is ampicillin plus a third-generation cephalosporin such as cefotaxime, a combination particularly useful in neonatal meningitis (mean duration of treatment 14 to 21 days), in patients at risk of nephrotoxicity and/or when therapeutic monitoring of aminoglycosides is not possible. Another potential substitute for the aminoglycoside is aztreonam. Triple combination therapy (such as amoxicillin plus cefotaxime and an aminoglycoside) could also be used for the first 2 to 3 days of life, followed by dual therapy after the microbiological results. In late-onset infections the combination oxacillin plus an aminoglycoside is widely recommended. However, vancomycin plus ceftazidime (+/- an aminoglycoside for the first 2 to 3 days) may be a better choice. Teicoplanin may be a substitute for vancomycin. However, the initial approach should always be modified by knowledge of the local bacterial epidemiology. After the microbiological results, treatment should be switched to narrower spectrum agents if a specific organism has been identified, and should be discontinued if cultures are negative and the neonate is in good clinical condition. Penicillins and third-generation cephalosporins are generally well tolerated in neonates. There is controversy regarding whether therapeutic drug monitoring of aminoglycosides will decrease toxicity (particularly renal damage) in neonates, and on the efficacy and safety of a single daily dose versus multiple daily doses of these drugs. Toxic effects caused by vancomycin are uncommon, but debate still exists over the need for therapeutic drug monitoring of this agent. When antibacterials are used in neonates, accurate determination of dosage is required, particularly for compounds with a low therapeutic index and in patients with renal failure. Very low birthweight infants are also particularly prone to antibacterial-induced toxicity.

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.

Tobramycin population pharmacokinetics in neonates

OBJECTIVE

To establish a tobramycin dosing schedule for neonates of various gestational ages.

METHODS

This was a retrospective study with prospective validation. A retrospective study in 470 neonates, with suspected septicemia in the first week of life, was performed. All patients received tobramycin according to the following scheme: neonates with a gestational age of less than 28 weeks received 3.5 mg/kg every 24 hours, neonates from 28 to 36 weeks received 2.5 mg/kg every 18 hours, neonates older than 36 weeks received 2.5 mg/kg every 12 hours. Trough and peak tobramycin serum levels were determined before drug administration and 30 minutes after the fourth dose. Tobramycin data were analyzed according to a one-compartment open model with use of NONMEM population pharmacokinetic software. Individual empirical Bayes estimates were generated on the basis of the population estimates and used to calculate predicted peak and trough levels for different doses and dosing intervals. To establish an optimal dosing regimen, target trough levels were set at below 2 mg/L and target peak levels were set above 5 to 10 mg/L. The dosing regimen was prospectively evaluated in 23 patients.

RESULTS

Of the 470 patients, 19.1% of measured peak and 32.8% of measured trough tobramycin serum levels were outside the desired therapeutic range, and 48.8% of neonates with a gestational age of less than 28 weeks had an aberrant trough level. With use of population estimates, the following dosing regimen was recommended: gestational age below 32 weeks, 4 mg/kg every 48 hours; gestational age between 32 and 37 weeks, 4 mg/kg every 36 hours, gestational age above 37 weeks, 4 mg/kg every 24 hours. With this dosing schedule, predicted peak levels were higher than 5 mg/L in 95.1% of the neonates. Predicted trough levels were higher than 2 mg/L in 1.9% of the neonates and higher than 1 mg/L in 7.6%. Prospectively measured peak levels were higher than 5 mg/L in all but one infant. Measured trough levels were higher than 2 mg/L in three patients and marginally higher than 1 mg/L in four patients.

CONCLUSIONS

With the use of this proposed schedule, taking into account differences in gestational ages, predicted peak levels will be therapeutic, whereas predicted trough levels will minimize toxicity.

Neonatal sepsis: pathogenesis and supportive therapy

Bacterial infections remain an important cause of neonatal mortality and morbidity. Pathogenesis of the neonate's predilection to infection are multifactorial. Factors directly attributable to the infant include humoral, phagocytic, and cellular deficiencies. Septic neonates may have reduced neutrophil storage pools that cause profound neutropenia. Both correlate with poor prognosis. Antibiotic administration is mandatory in neonatal sepsis. Supplementary treatments may be useful. Granulocyte transfusions, when available, provide neutrophils, improving the neonate's neutrophil count and neutrophil function. The efficacy of intravenous immunoglobulin (i.v.IG) is questionable because the prophylactic and therapeutic administration of i.v.IG fails to reduce the incidence of bacterial infections or affect the overall survival rate. Hyperimmune preparations seem to be more effective. The administration of granulocyte colony-stimulating factor induces myeloid progenitor proliferation, enhances the neutrophil storage pool, produces neutrophilia, and improves neutrophil function. More extensive, well-designed, and carefully control trials are needed to determine the benefit of supportive therapies for neonatal sepsis.

Ceftazidime pharmacokinetics in preterm infants: effects of renal function and gestational age

OBJECTIVE

The objectives of this study were (1) to determine the effects of gestational age on ceftazidime pharmacokinetics in the preterm infant, (2) to relate these effects to changes in glomerular filtration rate (GFR), and (3) to establish appropriate dosage recommendations for preterm infants on day 3 of life.

METHODS

Multiple-dose pharmacokinetics of ceftazidime (administered twice daily in a 25 or 50 mg/kg body weight intravenous dose) were evaluated in 136 preterm infants on day 3 of life. Blood samples were collected from an arterial catheter 0, 1/2, 1, 2, 4, 8, and 12 hours after the intravenous dose. An HPLC method was used to determine ceftazidime concentrations in serum. The GFR was studied simultaneously by means of the 24-hour continuous inulin infusion technique.

RESULTS

The total body clearance, volume of distribution, and elimination serum half-life of ceftazidime (mean +/- SD) were 55.7 +/- 34.4 ml/hr (37.3 +/- 11.9 ml/hr/kg), 496 +/- 228 ml (350 +/- 96 ml/kg), and 6.95 +/- 2.32 hours, respectively. The mean +/- SD peak and trough levels were 114.9 +/- 39.4 and 33.9 +/- 17.8 mg/L. All infants had a serum trough level above 5 mg/L. Clearance and volume of distribution of ceftazidime and GFR increased significantly with increasing gestational age, whereas serum trough levels and serum half-life of ceftazidime decreased significantly with increasing gestational age. Ceftazidime clearance increased significantly with increasing GFR. Prenatal exposure to indomethacin resulted in significantly lower GFR values and ceftazidime clearances.

CONCLUSIONS

Dosage recommendations for ceftazidime administration in preterm infants during the first week of life should be based on gestational age and GFR. Additional adjustments in dosage are indicated in preterm infants who are exposed prenatally to indomethacin.

Once-daily versus twice-daily administration of ceftazidime in the preterm infant

Ceftazidime pharmacokinetics in 28 preterm infants (gestational ages, 25.6 to 31.9 weeks) were studied on day 3 of life. Patients with suspected septicemia were randomized on day 1 of life in two groups. One group (n = 13) was administered 25 mg of ceftazidime per kg of body weight once daily, and the other (n = 15) was given 25 mg of ceftazidime per kg twice daily. Both groups also received 25 mg of amoxicillin per kg twice daily. Blood samples were collected on day 3 of life with an arterial catheter at 0, 0.5, 1, 2, 4, 8, and 12 h after an intravenous bolus injection. An additional blood sample was taken at 24 h from the group dosed once a day. High-performance liquid chromatography was used to determine serum ceftazidime concentrations. The pharmacokinetics of ceftazidime were best described by using a one-compartment model. The half-life for the elimination of the drug from serum, apparent volume of distribution, total body clearance of ceftazidime, and inulin clearance were not significantly different for both groups. The ceftazidime/inulin clearance ratio was 0.72 for both groups. However, trough concentrations in serum for the twice-daily group were significantly (P < 0.001) higher (42.0 +/- 13.4 mg/liter) than those for the once-daily group (13.1 +/- 4.7 mg/liter). The latter concentrations were all still substantially higher than the MIC of ceftazidime for major neonatal pathogens. We conclude that the currently recommended dosage of 25 mg of ceftazidime per kg twice daily for preterm infants with gestational ages below 32 weeks may be adjusted during the first days of life to one daily dose at 25 mg/kg, provided that for the empirical treatment of septicemia, amoxicillin at 25 mg/kg is also given twice daily.