Acute bacterial meningitis: current review and treatment update

Pharmacological targets and mechanisms of calycosin against meningitis

This report aimed to identity the potential anti-meningitis targets and mechanisms functioned by calycosin through network pharmacology approach. The bioinformatics databases were used to screen and collect the candidate genes/targets of calycosin and meningitis prior to identification of vital biotargets of calycosin-anti-meningitis. Additionally, the functional processes, signaling pathways of calycosin-anti-meningitis were screened and identified before further data visualization. As a result, all candidate and mapped biotargets of calycosin and meningitis were harvested before the vital targets of epidermal growth factor receptor (EGFR), tumor necrosis factor (TNF), epidermal growth factor (EGF), ataxia telangiectasia mutated protein (ATM), estrogen receptor alpha (ESR1), caspase-8 (CASP8), nerve growth factor (NGF) of calycosin-anti-meningitis were identified. The molecular processes of calycosin-anti-meningitis were screened and identified, including reduction of inflammatory development. Furthermore, the molecular pathways of calycosin-anti-meningitis were revealed, including suppression of NF-kappa B, Toll-like receptor, TNF signaling pathways. Molecular docking findings uncovered the docking capacity of calycosin with meningitis and potential pharmacological activity of calycosin against meningitis. In conclusion, these bioinformatic data uncovered the network targets and mechanisms of calycosin-anti-meningitis. And the current findings indicated that the vital targets might be used as potent biomarkers for detecting meningitis.

Meningococcal Meningitis: A Multicentric Hospital-based Study in Kathmandu, Nepal

Background:

The global epidemiology of meningococcal disease varies markedly by region and over time. In Nepal, information on serogroup of meningococci is not available since the 1983 serogroup A epidemic in Kathmandu.

Objective:

To provide some fundamental data on the circulating serogroups of meningococci for potential meningococcal immunization programs in Nepal.

Methods:

This cross-sectional prospective study was conducted from January 2017 to December 2018 among 387 clinically suspected meningitis cases. Cerebrospinal fluid samples were collected by lumbar puncture technique at five referral hospitals of Kathmandu and processed by conventional cultural techniques. Neisseria meningitidis was identified by colony morphology, Gram staining and oxidase test. Serogrouping of meningococci was performed by slide agglutination test. Antibiotic susceptibility testing was done by the modified Kirby Bauer disc diffusion method. The data was entered into IBM SPSS Statistics 21 software and a p-value of <0.05 was considered significant.

Results:

Thirty-two samples were positive by culture for a bacterial pathogen with 2.3% of meningococci. All except one meningococcal meningitis cases were aged below 15 years. All N.meningitidis isolates belonged to serogroup A and were susceptible to ceftriaxone, chloramphenicol, meropenem and minocycline; however, 22% isolates showed resistance to cotrimoxazole and 11% intermediate resistance to ciprofloxacin.

Conclusion:

The circulating serogroup of N. meningitidis in Kathmandu has not changed over the past 35 years. The prevalence of meningococcal meningitis in Kathmandu is low but might be underestimated due to the sole use of culture-based diagnostic methods. Detection of meningococci by alternative methods may be useful in the precise estimation of actual disease burden.

Streptococcus pneumoniae Cell Wall-Localized Trigger Factor Elicits a Protective Immune Response and Contributes to Bacterial Adhesion to the Host

Trigger factor (TF) has a known cytoplasmic function as a chaperone. In a previous study we showed that pneumococcal TF is also cell-wall localized and this finding combined with the immunogenic characteristic of TF, has led us to determine the vaccine potential of TF and decipher its involvement in pneumococcal pathogenesis. Bioinformatic analysis revealed that TF is conserved among pneumococci and has no human homologue. Immunization of mice with recombinant (r)TF elicited a protective immune response against a pneumococcal challenge, suggesting that TF contributes to pneumococcal pathogenesis. Indeed, rTF and an anti-rTF antiserum inhibited bacterial adhesion to human lung derived epithelial cells, indicating that TF contributes to the bacterial adhesion to the host. Moreover, bacteria lacking TF demonstrated reduced adhesion, in vitro, to lung-derived epithelial cells, neural cells and glial cells. The reduced adhesion could be restored by chromosomal complementation. Furthermore, bacteria lacking TF demonstrated significantly reduced virulence in a mouse model. Taken together, the ability of rTF to elicit a protective immune response, involvement of TF in bacterial adhesion, conservation of the protein among pneumococcal strains and the lack of human homologue, all suggest that rTF can be considered as a future candidate vaccine with a much broader coverage as compared to the currently available pneumococcal vaccines.

Prognostic factors among critically ill patients with community-acquired acute bacterial meningitis and acute kidney injury

OBJECTIVE

To investigate prognostic factors among critically ill patients with community-acquired bacterial meningitis and acute kidney injury.

METHODS

A retrospective study including patients admitted to a tertiary infectious disease hospital in Fortaleza, Brazil diagnosed with community-acquired bacterial meningitis complicated with acute kidney injury. Factors associated with death, mechanical ventilation and use of vasopressors were investigated.

RESULTS

Forty-one patients were included, with a mean age of 41.6 ± 15.5 years; 56% were males. Mean time between intensive care unit admission and acute kidney injury diagnosis was 5.8 ± 10.6 days. Overall mortality was 53.7%. According to KDIGO criteria, 10 patients were classified as stage 1 (24.4%), 18 as stage 2 (43.9%) and 13 as stage 3 (31.7%). KDIGO 3 significantly increased mortality (OR = 6.67; 95%CI = 1.23 - 36.23; p = 0.028). Thrombocytopenia was not associated with higher mortality, but it was a risk factor for KDIGO 3 (OR = 5.67; 95%CI = 1.25 - 25.61; p = 0.024) and for mechanical ventilation (OR = 6.25; 95%CI = 1.33 - 29.37; p = 0.02). Patients who needed mechanical ventilation by 48 hours from acute kidney injury diagnosis had higher urea (44.6 versus 74mg/dL, p = 0.039) and sodium (138.6 versus 144.1mEq/L; p = 0.036).

CONCLUSION

Mortality among critically ill patients with community-acquired bacterial meningitis and acute kidney injury is high. Acute kidney injury severity was associated with even higher mortality. Thrombocytopenia was associated with severer acute kidney injury. Higher urea was an earlier predictor of severer acute kidney injury than was creatinine.

Analysis of Death and Survival Factors Associated with Childhood Bacterial Meningitis at a Reference Pediatric Hospital in Antananarivo, Madagascar

BACKGROUND

Bacterial meningitis (BM) remains a global public health problem and most cases and deaths occur in Sub-Saharan Africa and especially in children less than five years old, due to a variety of factors. This study was conducted to determine the principal factors associated with death and survival of children due to BM in a typical African tertiary health facility.

METHODS

A retrospective case-control study of children hospitalized for BM was conducted in the University Hospital of Tsaralalàna (CHUMET). All children aged 3 to 59 months hospitalized for bacterial meningitis and confirmed by bacteriology were included. The cases were children who died from BM, and the controls were the survivors. Data was analyzed using Stata 13.

RESULTS

The factors associated with death were the number of siblings over 3 (14,48 [2,53 - 82,95]), overcrowding (9,31 [1,39 - 62,29]), time before hospitalization of more than five days (9,26 [1,36 - 62,92]), impaired consciousness (47,74 [6,24 - 364,96]), and meningococcal meningitis (36,68 [1,90 - 704,97]).

CONCLUSION

These factors are mainly indicators of low socioeconomic status, clinical severity of signs and particularly virulent organisms. The early detection of patients at risk allows clinicians to give them appropriate care right from admission. Further studies are necessary especially, the evaluation of the emergency care provided.

Acute bacterial meningitis in Iran: Systematic review and meta-analysis

Introduction

Bacterial meningitis persists in being a substantial cause of high mortality and severe neurological morbidity, despite the advances in antimicrobial therapy. Accurate data has not been available regarding the epidemiology of bacterial meningitis particularly in developing countries, yet. Indeed, the present systematic review provides a comprehensive data analysis on the prevalence and epidemiology of bacterial meningitis in Iran.

Methods

We systematically reviewed articles from 1994 to 2015. The reports which contained the prevalence and etiology of acute bacterial meningitis by valid clinical and laboratory diagnosis were comprised in the present study.

Results

Our analysis indicated that Streptococcus pneumoniae (30% [I2 = 56% p < 0.01]), Haemophilus influenza type b (15% [I2 = 82.75% p < 0.001]), coagulase negative staphylococci (CoNS) (14% [I2 = 60.5% p < 0.06]), and Neisseria meningitidis (13% [I2 = 74.16% p < 0.001]) were the most common cause of acute bacterial meningitis among meningitis cases in Iran. Notably, high frequency rates of nosocomial meningitis pathogens were detected in the present analysis.

Conclusions

It was magnificently attained that the majority of cases for bacterial meningitis in Iran could be avertable by public immunization schemes and by preventive care to inhibit the broadening of hospital acquired pathogens.

Role of neural barriers in the pathogenesis and outcome of Streptococcus pneumoniae meningitis

Bacterial meningitis is an inflammatory disease of the meninges of the central nervous system (CNS). Streptococcus pneumoniae (S. pneumoniae), Neisseria meningitidis, and Haemophilus influenzae are the major bacterial pathogens causing meningitis with S. pneumoniae being responsible for two thirds of meningitis cases in the developed world. To reach the CNS following nasopharyngeal colonization and bacteraemia, the bacteria traverse from the circulation across the blood brain barrier (BBB) and choroid plexus. While the BBB has a protective role in healthy individuals by shielding the CNS from neurotoxic substances circulating in the blood and maintaining the homeostasis within the brain environment, dysfunction of the BBB is associated with the pathophysiology of numerous neurologic disorders, including bacterial meningitis. Inflammatory processes, including release of a broad range of cytokines and free radicals, further increase vascular permeability and contribute to the excessive neural damage observed. Injury to the cerebral microvasculature and loss of blood flow auto-regulation promote increased intracranial pressure and may lead to vascular occlusion. Other common complications commonly associated with meningitis include abnormal neuronal hyper-excitability (e.g., seizures) and loss of hearing. Despite the existence of antibiotic treatment and adjuvant therapy, the relatively high mortality rate and the severe outcomes among survivors of pneumococcal meningitis in developing and developed countries increase the urgency in the requirement of discovering novel biomarkers for the early diagnosis as well as novel treatment approaches. The present review aimed to explore the changes in the brain vascular barriers, which allow S. pneumoniae to invade the CNS, and describe the resultant brain injuries following bacterial meningitis.

Specific detection of common pathogens of acute bacterial meningitis using an internally controlled tetraplex-PCR assay

Accurate and timely diagnosis of acute bacterial meningitis is critical for antimicrobial treatment of patients. Although PCR-based methods have been widely used for the diagnosis of acute meningitis caused by bacterial pathogens, the main disadvantage of these methods is their high cost. This disadvantage has hampered the widespread use of molecular assays in many developing countries. The application of multiplex assays and "in-house" protocols are two main approaches that can reduce the overall cost of a molecular test. In the present study, an internally controlled tetraplex-PCR was developed and validated for the specific detection of Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae in cerebrospinal fluid (CSF) samples. The analysis of a panel of other human pathogens showed no cross-reactivity in the assay. The analytical sensitivity of the in-house assay was 792.3 copies/ml, when all three bacteria were presentin the specimens. This value was calculated as 444.5, 283.7, 127.8 copies/ml when only S. pneumoniae, N. meningitidis and H. influenzae, respectively, were present. To demonstrate the diagnostic performance of the assay, a total of 150 archival CSF samples were tested and compared with a commercial multiplex real-time PCR kit. A diagnostic sensitivity of 92.8% and a specificity of 95.1% were determined for the present tetraplex-PCR assay. The results indicate that the established method is sensitive, specific and cost-effective, and can be used particularly in situations where the high cost of commercial kits prevents the use of molecular methods for the diagnosis of bacterial meningitis.