Lack of effectiveness of dexamethasone in neonatal bacterial meningitis

Response to Hydrocortisone in an Extremely Preterm Neonate With Late-Onset Sepsis, Meningoencephalitis, and Drug-Resistant Seizures

Corticosteroids are commonly used in children with bacterial meningitis; however, there are very few data regarding possible utility in neonates, particularly those born premature. We describe our experience using hydrocortisone in the treatment of a girl born at 26 weeks, 6 days gestation. She had suffered profound brain injury following late onset group B streptococcus sepsis and meningitis, and developed drug-resistant seizures. Because seizures continued despite treatment with phenobarbital, phenytoin, levetiracetam, lacosamide, and midazolam, intravenous hydrocortisone was added. We observed a marked decrease in focal electrographic seizures within 2 days of initiation of hydrocortisone. This experience suggests that corticosteroids could be a treatment option for drug-resistant seizures and status epilepticus in preterm neonates, particularly those with bacterial meningitis.

Group B Streptococcal Neonatal Meningitis

Neonatal bacterial meningitis is a devastating disease, associated with high mortality and neurological disability, in both developed and developing countries. Streptococcus agalactiae, commonly referred to as group B Streptococcus (GBS), remains the most common bacterial cause of meningitis among infants younger than 90 days. Maternal colonization with GBS in the gastrointestinal and/or genitourinary tracts is the primary risk factor for neonatal invasive disease. Despite prophylactic intrapartum antibiotic administration to colonized women and improved neonatal intensive care, the incidence and morbidity associated with GBS meningitis have not declined since the 1970s. Among meningitis survivors, a significant number suffer from complex neurological or neuropsychiatric sequelae, implying that the pathophysiology and pathogenic mechanisms leading to brain injury and devastating outcomes are not yet fully understood. It is imperative to develop new therapeutic and neuroprotective approaches aiming at protecting the developing brain. In this review, we provide updated clinical information regarding the understanding of neonatal GBS meningitis, including epidemiology, diagnosis, management, and human evidence of the disease's underlying mechanisms. Finally, we explore the experimental models used to study GBS meningitis and discuss their clinical and physiologic relevance to the complexities of human disease.

Clinical Characteristics and Risk Factors for Poor Outcome in Infants Less Than 90 Days of Age With Bacterial Meningitis in the United Kingdom and Ireland

BACKGROUND

To describe the clinical characteristics and risk factors associated with poor outcome in infants <90 days of age with bacterial meningitis.

METHODS

Prospective, enhanced, national population-based active surveillance for infants <90 days of age with bacterial meningitis in the United Kingdom and Ireland between July 2010 and July 2011. Infants were identified through the British Paediatric Surveillance Unit, laboratory surveillance and meningitis charities.

RESULTS

Clinical details was available for 263 of 298 (88%) infants where a bacterium was identified, 184 (70%) were born at term. Fever was reported in 143 (54%), seizures in 73 (28%), bulging fontanelle in 58 (22%), coma in 15 (6%) and neck stiffness in 7 (3%). Twenty-three (9%) died and 56/240 (23%) of the survivors had serious central nervous system complications at discharge. Temperature instability [odds ratio (OR), 2.99; 95% confidence interval (CI): 1.21-7.41], seizures (OR, 7.06; 95% CI: 2.80-17.81), cerebrospinal fluid protein greater than the median concentration (2275 mg/dL; OR, 2.62; 95% CI: 1.13-6.10) and pneumococcal meningitis (OR, 4.83; 95% CI: 1.33-17.58) were independently associated with serious central nervous system complications while prematurity (OR, 5.84; 95% CI: 2.02-16.85), low birthweight (OR, 8.48; 95% CI: 2.60-27.69), coma at presentation (OR, 31.85; 95% CI: 8.46-119.81) and pneumococcal meningitis (OR, 4.62; 95% CI: 1.19-17.91) were independently associated with death.

CONCLUSIONS

The classic features of meningitis were uncommon. The presentation in young infants is often nonspecific, and only half of cases presented with fever. A number of clinical and laboratory factors were associated with poor outcomes; further research is required to determine how knowledge of these risk factors might improve clinical management and outcomes.

Bird's Eye View of a Neonatologist: Clinical Approach to Emergency Neonatal Infection

Though the incidence of neonatal infection in term and near-term infants is relatively low, incidence of infection in preterm very low birth weight infants is as high as 20-30% and may result in neurodevelopmental impairment or mortality. Pediatricians should be familiar with recognition and emergency management of life-threatening neonatal infections, such as congenital pneumonia, early onset sepsis, late onset sepsis, bacterial and fungal meningitis, disseminated neonatal herpes simplex virus (HSV), and HSV meningoencephalitis. For the pediatrician, it is logical to approach the management of these infections by time of onset, i.e., early versus late onset of infection. Perinatal risk factors and simple laboratory tests, such as total white blood-cell count, immature/total ratio, and C-reactive protein are helpful in guiding the decision of antibiotics therapy. Successful management of these critical infections depends upon early diagnosis and timely administration of adequate antibiotics. Empiric antibiotic therapy must cover the most likely pathogens according to the risk factors of each individual neonate, and therapy duration is dependent upon culture results, clinical course, and the microorganism. Future research may focus on developing a practical neonatal sepsis score system based on risk factors and common biomarkers, which are readily available at bedside to make early accurate decisions and achieve better outcomes.

Improving the outcome of bacterial meningitis in newborn infants in Africa: reflections on recent progress

PURPOSE OF REVIEW

There has been a reduction in overall under fives mortality (UFM) but neonatal mortality has not fallen at the same rate as for older children. Bacterial meningitis remains a common, often unrecognized and devastating illness in many African newborns with high mortality and morbidity. Further progress in reducing UFM has to focus on quality of care for neonates. Recent efforts to improve diagnosis, treatment and outcome are reviewed.

RECENT FINDINGS

Diagnosis is often unsupported by laboratory tests and efforts have been made to improve the clinical diagnosis of bacterial meningitis. Simpler, robust bedside tests are being devised. The cause of bacterial meningitis is changing and first-line antimicrobial therapy and adjuvant therapies are evaluated. Programmes to reduce risk factors and prevent neonatal infections are identified.

SUMMARY

Neonatal care needs to improve in first referral hospitals with simple, low-cost, validated measures provided as bundles of care for both mother and child. First-line antibiotic therapy must be reconsidered in the light of increased infections by multiresistant and Gram-negative bacteria. Studies are needed for effective and safe lengths of antimicrobial therapy, the role of adjuvant therapy and the best anticonvulsants to use.

Adjuvant corticosteroids for reducing death in neonatal bacterial meningitis

BACKGROUND

Bacterial meningitis remains a significant cause of neonatal and childhood morbidity and mortality in many countries of the world, particularly in developing countries. In some instances, children recover but remain impaired as a result of neurological sequelae such as hearing loss, developmental delay and cognitive impairment.

OBJECTIVES

To assess the effectiveness and safety of adjunctive corticosteroids in reducing death and neurological sequelae in neonates with bacterial meningitis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 7), MEDLINE via PubMed (1966 to July 2015), African Index Medicus (up to January 2015), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (up to July 2015), EMBASE (up to July 2015) and the metaRegister of Controlled Trials (mRCT) for ongoing trials.

SELECTION CRITERIA

All randomised controlled trials (RCTs) or quasi-RCTs of adjunctive corticosteroids for treatment of neonates with bacterial meningitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed and extracted data on methods, participants, interventions and outcomes (all-cause death until hospital discharge, presence of sensorineural deafness at one year and presence of neurological deficits or developmental delay at two years, adverse events). Risk ratio (RR), risk difference (RD) and number needed to treat for an additional beneficial outcome (NNTB) or number needed to treat for an additional harmful outcome (NNTH) were calculated when appropriate. We assessed quality using the Cochrane risk of bias assessment tool and the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) system.

MAIN RESULTS

We found two trials with 132 participants that met our inclusion criteria. One of the included trials was a quasi-randomised trial.Adjunctive corticosteroids reduced the risk of death (typical RR 0.46, 95% confidence interval (CI) 0.24 to 0.88; typical RD -0.19, 95% CI -0.33 to -0.04; NNTB = 6; two studies, 132 participants, very low-quality evidence) but did not have a significant effect on the number of infants with sensorineural deafness at two years (RR 1.80, 95% CI 0.18 to 18.21; RD 0.04, 95% CI -0.12 to 0.21; one study, 38 participants, low-quality evidence). In one trial, dexamethasone reduced the likelihood of hearing loss at four to 10 weeks post discharge (RR 0.41, 95% CI 0.17 to 0.98; RD -0.25, 95% CI -0.48 to -0.01; one study, 59 participants, low-quality evidence). Data reported on the other outcomes of interest were insufficient.

AUTHORS' CONCLUSIONS

Very low-quality data from two randomised controlled trials suggest that some reduction in death and hearing loss may result from use of adjunctive steroids alongside standard antibiotic therapy for treatment of patients with neonatal meningitis. Benefit is not yet seen with regards to reduction in neurological sequelae. Researchers who wish to clarify these findings must conduct more robustly designed trials with greater numbers of participants, evaluating more relevant outcomes and providing adequate follow-up.

Corticosteroids for acute bacterial meningitis

BACKGROUND

In experimental studies, the outcome of bacterial meningitis has been related to the severity of inflammation in the subarachnoid space. Corticosteroids reduce this inflammatory response.

OBJECTIVES

To examine the effect of adjuvant corticosteroid therapy versus placebo on mortality, hearing loss and neurological sequelae in people of all ages with acute bacterial meningitis.

SEARCH METHODS

We searched CENTRAL (2015, Issue 1), MEDLINE (1966 to January week 4, 2015), EMBASE (1974 to February 2015), Web of Science (2010 to February 2015), CINAHL (2010 to February 2015) and LILACS (2010 to February 2015).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of corticosteroids for acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

We scored RCTs for methodological quality. We collected outcomes and adverse effects. We performed subgroup analyses for children and adults, causative organisms, low-income versus high-income countries, time of steroid administration and study quality.

MAIN RESULTS

We included 25 studies involving 4121 participants (2511 children and 1517 adults; 93 mixed population). Four studies were of high quality with no risk of bias, 14 of medium quality and seven of low quality, indicating a moderate risk of bias for the total analysis. Nine studies were performed in low-income countries and 16 in high-income countries.Corticosteroids were associated with a non-significant reduction in mortality (17.8% versus 19.9%; risk ratio (RR) 0.90, 95% confidence interval (CI) 0.80 to 1.01, P value = 0.07). A similar non-significant reduction in mortality was observed in adults receiving corticosteroids (RR 0.74, 95% CI 0.53 to 1.05, P value = 0.09). Corticosteroids were associated with lower rates of severe hearing loss (RR 0.67, 95% CI 0.51 to 0.88), any hearing loss (RR 0.74, 95% CI 0.63 to 0.87) and neurological sequelae (RR 0.83, 95% CI 0.69 to 1.00).Subgroup analyses for causative organisms showed that corticosteroids reduced mortality in Streptococcus pneumoniae (S. pneumoniae) meningitis (RR 0.84, 95% CI 0.72 to 0.98), but not in Haemophilus influenzae (H. influenzae) orNeisseria meningitidis (N. meningitidis) meningitis. Corticosteroids reduced severe hearing loss in children with H. influenzae meningitis (RR 0.34, 95% CI 0.20 to 0.59) but not in children with meningitis due to non-Haemophilus species.In high-income countries, corticosteroids reduced severe hearing loss (RR 0.51, 95% CI 0.35 to 0.73), any hearing loss (RR 0.58, 95% CI 0.45 to 0.73) and short-term neurological sequelae (RR 0.64, 95% CI 0.48 to 0.85). There was no beneficial effect of corticosteroid therapy in low-income countries.Subgroup analysis for study quality showed no effect of corticosteroids on severe hearing loss in high-quality studies.Corticosteroid treatment was associated with an increase in recurrent fever (RR 1.27, 95% CI 1.09 to 1.47), but not with other adverse events.

AUTHORS' CONCLUSIONS

Corticosteroids significantly reduced hearing loss and neurological sequelae, but did not reduce overall mortality. Data support the use of corticosteroids in patients with bacterial meningitis in high-income countries. We found no beneficial effect in low-income countries.

Challenges in the diagnosis and management of neonatal sepsis

Neonatal sepsis is the third leading cause of neonatal mortality and a major public health problem, especially in developing countries. Although recent medical advances have improved neonatal care, many challenges remain in the diagnosis and management of neonatal infections. The diagnosis of neonatal sepsis is complicated by the frequent presence of noninfectious conditions that resemble sepsis, especially in preterm infants, and by the absence of optimal diagnostic tests. Since neonatal sepsis is a high-risk disease, especially in preterm infants, clinicians are compelled to empirically administer antibiotics to infants with risk factors and/or signs of suspected sepsis. Unfortunately, both broad-spectrum antibiotics and prolonged treatment with empirical antibiotics are associated with adverse outcomes and increase antimicrobial resistance rates. Given the high incidence and mortality of sepsis in preterm infants and its long-term consequences on growth and development, efforts to reduce the rates of infection in this vulnerable population are one of the most important interventions in neonatal care. In this review, we discuss the most common questions and challenges in the diagnosis and management of neonatal sepsis, with a focus on developing countries.

Current concepts in the treatment of bacterial meningitis beyond the neonatal period

The epidemiology and treatment approach to bacterial meningitis has changed dramatically since the advent of antimicrobial therapy. New vaccines against meningeal pathogens have been implemented into national immunization programs successfully around the world. Antibiotic resistance has had a considerable impact on the efficacy of several therapeutic agents. In this review, the authors will discuss the principles of antibiotic chemotherapy, focusing on new agents for the treatment of penicillin-resistant pneumococci and adjunctive treatments to reduce the inflammatory response to bacterial infection of the meninges.

The microbial spectrum of neonatal sepsis in Uganda: recovery of culturable bacteria in mother-infant pairs

Neonatal sepsis in the developing world is incompletely characterized. We seek to characterize the microbial spectrum involved in sepsis and determine the role of maternal transmission by comparing organisms that can be cultured from septic newborn infants and their mothers. From 80 consecutive mother-infant pairs meeting clinical criteria for neonatal sepsis, we collected infant blood and spinal fluid, and maternal blood and vaginal specimens. Identifiable bacteria were recovered from the blood in 32.5% of infants, and from 2.5% of cerebrospinal fluid cultures, for a total of 35% recoverable putative causative agents. Bacteria recovered from vaginal specimens were not concordant with those recovered from infants. Similarly there was no concordance of bacteria recovered from blood and cerebrospinal fluid. We conclude that relying on traditional bacterial culture techniques does not adequately delineate the role of maternal versus environmental sources of neonatal sepsis in this setting. More sensitive molecular approaches will be needed to properly characterize the maternal and environmental microbial community involved in neonatal sepsis in such developing countries.

Pathophysiology of neonatal acute bacterial meningitis

Neonatal meningitis is a severe acute infectious disease of the central nervous system and an important cause of morbidity and mortality worldwide. The inflammatory reaction involves the meninges, the subarachnoid space and the brain parenchymal vessels and contributes to neuronal injury. Neonatal meningitis leads to deafness, blindness, cerebral palsy, seizures, hydrocephalus or cognitive impairment in approximately 25-50 % of survivors. Bacterial pathogens can reach the blood-brain barrier and be recognized by antigen-presenting cells through the binding of Toll-like receptors. They induce the activation of NFκB or mitogen-activated protein kinase pathways and subsequently upregulate leukocyte populations and express numerous proteins involved in inflammation and the immune response. Many brain cells can produce cytokines, chemokines and other pro-inflammatory molecules in response to bacterial stimuli, and polymorphonuclear leukocytes are attracted, activated and released in large amounts of superoxide anion and nitric oxide, leading to peroxynitrite formation and generating oxidative stress. This cascade leads to lipid peroxidation, mitochondrial damage and breakdown of the blood-brain barrier, thus contributing to cell injury during neonatal meningitis. This review summarizes information on the pathophysiology and adjuvant treatment of acute bacterial meningitis in neonates.

[Clinical outcome and prognosis of neonatal bacterial meningitis]

OBJECTIVES

To study the epidemiological, clinical, and bacteriological aspects as well as the outcome of neonatal bacterial meningitis and analyze the factors of poor prognosis of this condition.

PATIENTS AND METHODS

We report a retrospective analysis of 44 cases of neonatal bacterial meningitis hospitalized in the pediatric unit of Tahar Sfar Hospital in Mahdia, Tunisia, between January 1996 and December 2010. Inclusion criteria were infants less than 29 days of age who were hospitalized for bacterial meningitis diagnosed on either the presence of bacteria in cerebrospinal fluid or with more than 50 cells/mm(3), predominance of neutrophils, and the protein level greater than 1.2g/l. Clinical data were obtained through the analysis of patient files. Statistical analysis was based on the Chi(2) test, and P-values less than 0.05 were considered statistically significant.

RESULTS

The incidence of neonatal bacterial meningitis was 0.49 per 1000 live births. The patients were premature in 20.4 % and low birth weight in 13.6 % of cases. The clinical presentation was not specific for most cases. The main signs at admission were hyperthermia (43.2 %), refusal to nurse (20.4 %), seizures (18.2 %), and respiratory distress (13.6 %). The cerebrospinal fluid culture was positive in 36.4 % of cases. The group B streptococcus was the most frequently isolated (62.5 %) followed by Escherichia coli (12.5 %). The association of cefotaxime-ampicillin-gentamicin was used as the first treatment in all cases. Ofloxacin was associated with initial antibiotic therapy during the first 5 days in 20.4 % of cases. The mortality rate was 15.9 % and the rate of neurological sequelae in survivors was 21.6 %. Prematurity, low birth weight, shock, respiratory distress, and pleocytosis of less than 500 cells/mm(3) were the main factors of a poor prognosis. The addition of ofloxacin to the initial antibiotic therapy was associated with a decreased rate of neurological sequelae in survivors (11 % vs. 25 %, P=0.042).

CONCLUSION

This study emphasizes the severity of neonatal bacterial meningitis with high rates of mortality and neurological sequelae, especially in premature and low birth weight infants. An early diagnosis and effective antibiotic therapy is needed to improve the prognosis.

Corticosteroids for acute bacterial meningitis

BACKGROUND

In experimental studies, the outcome of bacterial meningitis has been related to the severity of inflammation in the subarachnoid space. Corticosteroids reduce this inflammatory response.

OBJECTIVES

To examine the effect of adjuvant corticosteroid therapy versus placebo on mortality, hearing loss and neurological sequelae in people of all ages with acute bacterial meningitis.

SEARCH METHODS

We searched CENTRAL 2012, Issue 12, MEDLINE (1966 to January week 2, 2013), EMBASE (1974 to January 2013), Web of Science (2010 to January 2013), CINAHL (2010 to January 2013) and LILACS (2010 to January 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of corticosteroids for acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

We scored RCTs for methodological quality. We collected outcomes and adverse effects. We performed subgroup analyses for children and adults, causative organisms, low-income versus high-income countries, time of steroid administration and study quality.

MAIN RESULTS

Twenty-five studies involving 4121 participants were included. Corticosteroids were associated with a non-significant reduction in mortality (17.8% versus 19.9%; risk ratio (RR) 0.90, 95% confidence interval (CI) 0.80 to 1.01, P = 0.07). A similar non-significant reduction in mortality was observed in adults receiving corticosteroids (RR 0.74, 95% CI 0.53 to 1.05, P = 0.09). Corticosteroids were associated with lower rates of severe hearing loss (RR 0.67, 95% CI 0.51 to 0.88), any hearing loss (RR 0.74, 95% CI 0.63 to 0.87) and neurological sequelae (RR 0.83, 95% CI 0.69 to 1.00).Subgroup analyses for causative organisms showed that corticosteroids reduced mortality in Streptococcus pneumoniae (S. pneumoniae) meningitis (RR 0.84, 95% CI 0.72 to 0.98), but not in Haemophilus influenzae (H. influenzae) orNeisseria meningitidis (N. meningitidis) meningitis. Corticosteroids reduced severe hearing loss in children with H. influenzae meningitis (RR 0.34, 95% CI 0.20 to 0.59) but not in children with meningitis due to non-Haemophilus species.In high-income countries, corticosteroids reduced severe hearing loss (RR 0.51, 95% CI 0.35 to 0.73), any hearing loss (RR 0.58, 95% CI 0.45 to 0.73) and short-term neurological sequelae (RR 0.64, 95% CI 0.48 to 0.85). There was no beneficial effect of corticosteroid therapy in low-income countries.Subgroup analysis for study quality showed no effect of corticosteroids on severe hearing loss in high-quality studies.Corticosteroid treatment was associated with an increase in recurrent fever (RR 1.27, 95% CI 1.09 to 1.47), but not with other adverse events.

AUTHORS' CONCLUSIONS

Corticosteroids significantly reduced hearing loss and neurological sequelae, but did not reduce overall mortality. Data support the use of corticosteroids in patients with bacterial meningitis in high-income countries. We found no beneficial effect in low-income countries.

Bacterial meningitis post-PCV7: declining incidence and treatment

The epidemiology of bacterial meningitis in the United States has changed tremendously in the past 20 years. Since the introduction of the Haemophilus influenzae type b vaccine in 1988, the incidence of H. influenzae type b meningitis has declined by at least 97%, and Streptococcus pneumoniae has emerged as the most common etiologic agent. The PCV7 (7-valent pneumococcal conjugate vaccine [Prevnar]; Wyeth Pharmaceuticals) vaccine, which targets 7 pneumococcal serotypes, was introduced in 2000 and has had an enormous impact on both the incidence and epidemiology of bacterial meningitis. This article reviews the impact of the PCV7 vaccine and the most up-to-date evidence on diagnosis and empiric therapy of suspected bacterial meningitis in the current day.

Role of dexamethasone in neonatal meningitis: a randomized controlled trial

OBJECTIVES

To evaluate the role of dexamethasone therapy in neonatal meningitis in a randomized placebo controlled trial.

METHODS

The participants were eighty neonates with meningitis randomized to receive dexamethasone or saline placebo. Dexamethasone was started prior to the first dose of antibiotics in the dose of 0.15 mg/kg intravenous 6 hourly for 2 d. Primary outcome measure was mortality. Secondary outcome measures included progression of systemic inflammatory response syndrome (SIRS) up to 48 h, differences in cerebrospinal fluid (CSF) cytokines between baseline levels and 24 h after enrolment and brain stem auditory evoked response (BAER) after 4 to 6 wk of discharge.

RESULTS

Baseline variables were comparable in both the groups. Mortality was significantly decreased in dexamethasone group (p = 0.005) and the absolute risk difference was 27.5 % (95 % CI 9.5-45.8 %). There was a significant reduction in cells per mm(3) (62.5 vs. 100) and proteins (162 vs. 217.5 mg/dl) after 24 h of treatment in the dexamethasone group. IL-1β was significantly reduced after 24 h in dexamethasone group (290 vs 665 pg/ml). TNF- α was significantly lower (157.5 vs 427.5 pg/ml) and sugar significantly higher (50 vs 38 mg/dl) in the dexamethasone group after 24 h. Significant difference was noted between dexamethasone and saline groups in the progression of SIRS.

CONCLUSIONS

Dexamethasone significantly reduced fatality, progression of SIRS and CSF inflammatory indices.

Advances in treatment of bacterial meningitis

Bacterial meningitis kills or maims about a fifth of people with the disease. Early antibiotic treatment improves outcomes, but the effectiveness of widely available antibiotics is threatened by global emergence of multidrug-resistant bacteria. New antibiotics, such as fluoroquinolones, could have a role in these circumstances, but clinical data to support this notion are scarce. Additionally, whether or not adjunctive anti-inflammatory therapies (eg, dexamethasone) improve outcomes in patients with bacterial meningitis remains controversial; in resource-poor regions, where the disease burden is highest, dexamethasone is ineffective. Other adjunctive therapeutic strategies, such as glycerol, paracetamol, and induction of hypothermia, are being tested further. Therefore, bacterial meningitis is a substantial and evolving therapeutic challenge. We review this challenge, with a focus on strategies to optimise antibiotic efficacy in view of increasingly drug-resistant bacteria, and discuss the role of current and future adjunctive therapies.

The role of dexamethasone in the treatment of bacterial meningitis - a systematic review

Corticosteroids are used as an adjunct to antibiotics in the treatment of bacterial meningitis in an attempt to attenuate the intrathecal inflammatory response and thereby reduce mortality and morbidity. The purpose of the present paper is to provide a review of clinical studies of corticosteroids in the treatment of bacterial meningitis. Relevant literature was found in PubMed, the Cochrane databases, and references in studies. Forty-four publications of relevance were identified, comprising 29 publications of randomised studies, 10 publications reporting either non- or quasi-randomised studies, and five reporting retrospective studies, and nine meta-analyses. Taken together, dexamethasone treatment may be associated with a lower mortality in adults and fewer neurological and auditory sequelae in adults and children from high-income countries, in particular in adults suffering from pneumococcal meningitis. In contrast, studies conducted in developing countries have yielded less favourable results.

Choice and duration of antimicrobial therapy for neonatal sepsis and meningitis

Neonatal sepsis is associated with increased mortality and morbidity including neurodevelopmental impairment and prolonged hospital stay. Signs and symptoms of sepsis are nonspecific, and empiric antimicrobial therapy is promptly initiated after obtaining appropriate cultures. However, many preterm and low birth weight infants who do not have infection receive antimicrobial agents during hospital stay. Prolonged and unnecessary use of antimicrobial agents is associated with deleterious effects on the host and the environment. Traditionally, the choice of antimicrobial agents is based on the local policy, and the duration of therapy is decided by the treating physician based on clinical symptoms and blood culture results. In this paper, we discuss briefly the causative organism of neonatal sepsis in both the developed and developing countries. We review the evidence for appropriate choice of empiric antimicrobial agents and optimal duration of therapy in neonates with suspected sepsis, culture-proven sepsis, and meningitis. Moreover, there is significant similarity between the causative organisms for early- and late-onset sepsis in developing countries. The choice of antibiotic described in this paper may be more applicable in developed countries.

Systematic review: neonatal meningitis in the developing world

Meningitis is more common in the neonatal period than any other time in life and is an important cause of morbidity and mortality globally. Despite the majority of the burden occurring in the developing world, the majority of the existing literature originates from wealthy countries. Mortality from neonatal meningitis in developing countries is estimated to be 40-58%, against 10% in developed countries. Important differences exist in the spectrum of pathogens isolated from cerebrospinal fluid cultures in developed versus developing countries. Briefly, while studies in developed countries have generally found Group B streptococcus (GBS), Escherichia coli and Listeria monocytogenes as important organisms, we describe how in the developing world results have varied; particularly regarding GBS, other Gram negatives (excluding E. coli), Listeria and Gram-positive organisms. The choice of empiric antibiotics should take into consideration local epidemiology if known, early versus late disease, resistance patterns and availability within resource constraints. Gaps in knowledge, the role of adjuvant therapies and future directions for research are explored.

Association of bacteria with hydrocephalus in Ugandan infants

OBJECT

Infantile hydrocephalus in East Africa is predominantly postinfectious. The microbial origins remain elusive, since most patients present with postinfectious hydrocephalus after antecedent neonatal sepsis (NS) has resolved.

METHODS

To characterize this syndrome in Ugandan infants, the authors used polymerase chain reaction targeting bacterial 16S ribosomal DNA from CSF to determine if bacterial residua from recent infections were detectable. Bacteria were identified based on the relationship of genetic sequences obtained with reference bacteria in public databases. The authors evaluated samples from patients presenting during dry and rainy seasons and performed environmental sampling in the villages of patients.

RESULTS

Bacterial DNA was recovered from 94% of patients. Gram-negative bacteria in the phylum Proteobacteria were the most commonly detected. Within this phylum, Gammaproteobacteria dominated in patients presenting after infections during the rainy season, and Betaproteobacteria was most common following infections during the dry season. Acinetobacter species were identified in the majority of patients admitted after rainy season infection.

CONCLUSIONS

Postinfectious hydrocephalus in Ugandan infants appears associated with predominantly enteric gram-negative bacteria. These findings highlight the need for linking these cases with antecedent NS to develop more effective treatment and prevention strategies.

Bacterial pore-forming cytolysins induce neuronal damage in a rat model of neonatal meningitis

BACKGROUND

Group B Streptococcus (GBS) and Streptococcus pneumoniae (SP) are leading causes of bacterial meningitis in neonates and children. Each pathogen produces a pore-forming cytolytic toxin, β-hemolysin/cytolysin (β-h/c) by GBS and pneumolysin by SP. The aim of this study was to understand the role of these pore-forming cytotoxins, in particular of the GBS β-h/c, as potential neurotoxins in experimental neonatal meningitis.

METHODS

Meningitis was induced in 7- and 11-day-old rats by intracisternal injection of wild type (WT) GBS or SP and compared with isogenic β-h/c- or pneumolysin-deficient mutants, or a double mutant of SP deficient in pneumolysin and hydrogen peroxide production.

RESULTS

GBS β-h/c and SP pneumolysin contributed to neuronal damage, worsened clinical outcome and weight loss, but had no influence on the early kinetics of leukocyte influx and bacterial growth in the cerebrospinal fluid. In vitro, β-h/c-induced neuronal apoptosis occurred independently of caspase-activation and was not preventable by the broad spectrum caspase-inhibitor z-VAD-fmk.

CONCLUSIONS

These data suggest that both cytolytic toxins, the GBS β-h/c and SP pneumolysin, contribute to neuronal damage in meningitis and extend the concept of a key role for bacterial pore-forming cytolysins in the pathogenesis and sequelae of neonatal meningitis.

Corticosteroids for acute bacterial meningitis

BACKGROUND

In experimental studies, the outcome of bacterial meningitis has been related to the severity of inflammation in the subarachnoid space. Corticosteroids reduce this inflammatory response.

OBJECTIVES

To examine the effect of adjuvant corticosteroid therapy versus placebo on mortality, hearing loss and neurological sequelae in people of all ages with acute bacterial meningitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, issue 1), MEDLINE (1966 to February 2010), EMBASE (1974 to February 2010) and Current Contents (2001 to February 2010).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of corticosteroids for acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

We scored RCTs for methodological quality. We collected outcomes and adverse effects. We performed subgroup analyses for children and adults, causative organisms, low-income versus high-income countries, time of steroid administration and study quality.

MAIN RESULTS

Twenty-four studies involving 4041 participants were included. Similar numbers of participants died in the corticosteroid and placebo groups (18.0% versus 20.0%; risk ratio (RR) 0.92, 95% confidence interval (CI) 0.82 to 1.04, P = 0.18). There was a trend towards lower mortality in adults receiving corticosteroids (RR 0.74, 95% CI 0.53 to 1.05, P = 0.09). Corticosteroids were associated with lower rates of severe hearing loss (RR 0.67, 95% CI 0.51 to 0.88), any hearing loss (RR 0.76, 95% CI 0.64 to 0.89) and neurological sequelae (RR 0.83, 95% CI 0.69 to 1.00).Subgroup analyses for causative organisms showed that corticosteroids reduced severe hearing loss in Haemophilus influenzae meningitis (RR 0.34, 95% CI 0.20 to 0.59) and reduced mortality in Streptococcus pneumoniae meningitis (RR 0.84, 95% CI 0.72 to 0.98).In high-income countries, corticosteroids reduced severe hearing loss (RR 0.51, 95% CI 0.35 to 0.73), any hearing loss (RR 0.58, 95% CI 0.45 to 0.73) and short-term neurological sequelae (RR 0.64, 95% CI 0.48 to 0.85). There was no beneficial effect of corticosteroid therapy in low-income countries.Subgroup analysis for study quality showed no effect of corticosteroids on severe hearing loss in high quality studies.Corticosteroid treatment was associated with an increase in recurrent fever (RR 1.27, 95% CI 1.09 to 1.47), but not with other adverse events.

AUTHORS' CONCLUSIONS

Corticosteroids significantly reduced hearing loss and neurological sequelae, but did not reduce overall mortality. Data support the use of corticosteroids in patients with bacterial meningitis in high-income countries. We found no beneficial effect in low-income countries.

Central nervous system infections as a cause of an altered mental status? What is the pathogen growing in your central nervous system?

There are several central nervous system (CNS) infections (meningitis, encephalitis, and brain abscess), any of which may present with an altered level of consciousness. Because CNS infections can have a devastating outcome, it is important to recognize the presence of a CNS infection and begin treatment as soon as possible because early appropriate therapy may, in some cases, limit morbidity and mortality.

Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis

The epidemiology of bacterial meningitis has changed as a result of the widespread use of conjugate vaccines and preventive antimicrobial treatment of pregnant women. Given the significant morbidity and mortality associated with bacterial meningitis, accurate information is necessary regarding the important etiological agents and populations at risk to ascertain public health measures and ensure appropriate management. In this review, we describe the changing epidemiology of bacterial meningitis in the United States and throughout the world by reviewing the global changes in etiological agents followed by specific microorganism data on the impact of the development and widespread use of conjugate vaccines. We provide recommendations for empirical antimicrobial and adjunctive treatments for clinical subgroups and review available laboratory methods in making the etiological diagnosis of bacterial meningitis. Finally, we summarize risk factors, clinical features, and microbiological diagnostics for the specific bacteria causing this disease.

Acute bacterial meningitis

Despite advances in medical care including antibiotics and vaccines, meningitis still has a high morbidity and mortality rate, especially in certain high-risk patients. Early diagnosis with the administration of appropriate antibiotics remains the key element of management. This article highlights methods of diagnosis, differential diagnoses, treatment options, and complications of treating bacterial meningitis.

Corticosteroids for acute bacterial meningitis

BACKGROUND

In experimental studies, the clinical outcome of acute bacterial meningitis has been related to the severity of the inflammatory process in the subarachnoidal space. Treatment with corticosteroids can reduce this inflammatory response and thereby may improve outcome. We conducted a meta-analysis of randomised controlled trials (RCTs) of adjuvant corticosteroids in the treatment of acute bacterial meningitis.

OBJECTIVES

We conducted a systematic review examining the efficacy and safety of adjuvant corticosteroid therapy in acute bacterial meningitis.

SEARCH STRATEGY

In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2006); MEDLINE (1966 to July 2006); EMBASE (1974 to June 2006); Current Contents (2001 to June 2006); and reference lists of all articles. We also contacted manufacturers and researchers in the field.

SELECTION CRITERIA

Eligible published and non-published RCTs on corticosteroids as adjuvant therapy in acute bacterial meningitis. Patients of any age and in any clinical condition, treated with antibacterial agents and randomised to corticosteroid therapy (or placebo) of any type, could be included. At least case fatality rate or hearing loss had to be recorded for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Adverse effects were collected from the trials. Additional analyses were performed for children and adults, causative organisms, and low-income and developed countries.

MAIN RESULTS

Eighteen studies involving 2750 people were included. Overall, adjuvant corticosteroids were associated with lower case fatality (relative risk (RR) 0.83, 95% CI 0.71 to 0.99), lower rates of severe hearing loss (RR 0.65, 95% CI 0.47 to 0.91) and long-term neurological sequelae (RR 0.67, 95% CI 0.45 to 1.00). In children, corticosteroids reduced severe hearing loss (RR 0.61, 95% CI 0.44 to 0.86). In adults, corticosteroids gave significant protection against death (RR 0.57, 95% CI 0.40 to 0.81) and short-term neurological sequelae (RR 0.42, 95% CI 0.22 to 0.87). Subgroup analysis for causative organisms showed that corticosteroids reduced mortality in patients with meningitis due to Streptococcus pneumoniae (RR 0.59, 95% CI 0.45 to 0.77) and reduced severe hearing loss in children with meningitis due to Haemophilus influenzae (RR 0.37, 95% CI 0.20 to 0.68); subgroup analysis for patients with meningococcal showed a nonsignificant favourable trend in mortality (RR 0.71, 95% CI 0.31 to 1.62). Sub analyses for high-income and low-income countries of the effect of corticosteroids on mortality showed RRs of 0.83 (95% CI 0.52 to 1.05) and 0.87 (95% CI 0.72 to 1.05), respectively. Corticosteroids were protective against short-term neurological sequelae in patients with bacterial meningitis high-income countries (RR 0.56, 95% CI 0.3 to 0.84); in low-income countries this RR was 1.09 (95% CI 0.83 to 1.45). For children with bacterial meningitis admitted in high-income countries, corticosteroids showed a protective effect of on severe hearing loss (RR 0.61, 95% CI 0.41 to 0.90) and favourable point estimates for severe hearing loss associated with non-Haemophilus influenzae meningitis (RR 0.51, 95% CI 0.23 to 1.13) and short-term neurological sequelae (RR 0.72, 95% CI 0.39 to 1.33). For children in low-income countries, the use of corticosteroids was neither associated with benefit nor with harmful effects. Overall, adverse events were not increased significantly with the use of corticosteroids.

AUTHORS' CONCLUSIONS

Overall, corticosteroids significantly reduced rates of mortality, severe hearing loss and neurological sequelae. In adults with community-acquired bacterial meningitis, corticosteroid therapy should be administered in conjunction with the first antibiotic dose. In children, data support the use of adjunctive corticosteroids in children in high-income countries. We found no beneficial effect of corticosteroids for children in low-income countries.

Do Corticosteroids Prevent Hearing Loss in Pediatric Bacterial Meningitis? An Analysis of the Evidence

We reviewed the MEDLINE database of articles published from January 1966 through December 2001 in search of data on the ability of the corticosteroid dexamethasone to protect against sensorineural hearing loss in children with meningitis. We found 1,034 articles that matched our keyword entries, and after various exclusions, we winnowed this number down to 16 articles that contained adequate data regarding audiometric evaluation and follow-up. The 16 articles included reports of 11 randomized controlled trials (only 10 are considered in this analysis), two meta-analyses, two retrospective case series, and two consensus statements. Of the 10 clinical trials (all of which contained level I evidence), four showed that dexamethasone had a protective effect and six showed that it did not. The authors of the two meta-analyses (both level I) concluded that there was a protective effect, and the authors of the two retrospective case series (both level IV) concluded that there was not. Both consensus statements (both level V) recommended the use of dexamethasone only in Haemophilus influenzae meningitis. We conclude that well-designed studies with level I evidence have shown that the benefit of dexamethasone in preventing hearing loss in children with meningitis remains unclear. Significant variables in treatment response include the specific pathogen, the type of antibiotic, and the timing of dexamethasone administration.

Dexamethasone aggravates hippocampal apoptosis and learning deficiency in pneumococcal meningitis in infant rats

In an infant rat model of pneumococcal meningitis the effect of dexamethasone on neuronal injury in the hippocampus and on learning disability after recovery from the disease was examined. Treatment with dexamethasone or vehicle was started 18 h after infection, concomitant with antibiotics. Neuronal apoptosis in the hippocampal dentate gyrus 34 h after infection was significantly aggravated by dexamethasone treatment compared with vehicle controls (p = 0.02). Three weeks after acute pneumococcal meningitis, learning capacity of animals was assessed in the Morris water maze. The results showed a significantly impaired learning performance of infected animals treated with dexamethasone compared with vehicle controls (p = 0.01). Dexamethasone had no effect on hippocampal injury or learning in uninfected controls. Thus, dexamethasone as adjuvant therapy increased hippocampal cell injury and reduced learning capacity in this model of pneumococcal meningitis in infant rats.

Neonatal meningitis

Twelve years ago an annotation was published in Archives of Disease in Childhood regarding the antibiotic treatment of suspected neonatal meningitis. The authors recommended the use of cephalosporins rather than chloramphenicol and advocated intraventricular aminoglycoside treatment in selected cases. They noted the absence of clinical trials with third generation cephalosporins that showed an improvement in mortality or neurological outcome.

Neonatal bacterial meningitis

Despite major improvements in infant intensive care, neonatal meningitis remains a devastating disease. Survivors of bacterial meningitis are at high-risk for life-long neurological handicaps, and despite a reduction in mortality, the morbidity of neonatal meningitis has not changed substantially over the last thirty years. A substantial improvement in outcome is unlikely to result from further refinements in ICU technology or new antibiotics. However, recent advancements in our understanding of the pathogenesis of meningitis and the pathophysiology of brain injury in meningitis may provide the opportunity to interrupt the mechanisms that allow bacteria to enter the central nervous system and initiate the inflammatory response. Strategies aimed at modulating the inflammatory response must be chosen carefully, so as not to disrupt normal host responses needed for the infant to recover from the infectious episode.

Matrix metalloproteinases contribute to brain damage in experimental pneumococcal meningitis

The present study was performed to evaluate the role of matrix metalloproteinases (MMP) in the pathogenesis of the inflammatory reaction and the development of neuronal injury in a rat model of bacterial meningitis. mRNA encoding specific MMPs (MMP-3, MMP-7, MMP-8, and MMP-9) and the inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) were significantly (P < 0.04) upregulated, compared to the beta-actin housekeeping gene, in cortical homogenates at 20 h after infection. In parallel, concentrations of MMP-9 and TNF-alpha in cerebrospinal fluid (CSF) were significantly increased in rats with bacterial meningitis compared to uninfected animals (P = 0.002) and showed a close correlation (r = 0.76; P < 0. 001). Treatment with a hydroxamic acid-type MMP inhibitor (GM6001; 65 mg/kg intraperitoneally every 12 h) beginning at the time of infection significantly lowered the MMP-9 (P < 0.02) and TNF-alpha (P < 0.02) levels in CSF. Histopathology at 25.5 +/- 5.7 h after infection showed neuronal injury (median [range], 3.5% [0 to 17.5%] of the cortex), which was significantly (P < 0.01) reduced to 0% (0 to 10.8%) by GM6001. This is the first report to demonstrate that MMPs contribute to the development of neuronal injury in bacterial meningitis and that inhibition of MMPs may be an effective approach to prevent brain damage as a consequence of the disease.