The management of acute meningitis: an update

Central nervous system infections in the tropics

PURPOSE OF REVIEW

Emerging and re-emerging central nervous system (CNS) infections are a major public health concern in the tropics. The reasons for this are myriad; climate change, rainfall, deforestation, increased vector density combined with poverty, poor sanitation and hygiene. This review focuses on pathogens, which have emerged and re-emerged, with the potential for significant morbidity and mortality.

RECENT FINDINGS

In recent years, multiple acute encephalitis outbreaks have been caused by Nipah virus, which carries a high case fatality. Arboviral infections, predominantly dengue, chikungunya and Zika are re-emerging increasingly especially in urban areas due to changing human habitats, vector behaviour and viral evolution. Scrub typhus, another vector borne disease caused by the bacterium Orientia tsutsugamushi , is being established as a leading cause of CNS infections in the tropics.

SUMMARY

A syndromic and epidemiological approach to CNS infections in the tropics is essential to plan appropriate diagnostic tests and management. Rapid diagnostic tests facilitate early diagnosis and thus help prompt initiation and focusing of therapy to prevent adverse outcomes. Vector control, cautious urbanization and deforestation, and reducing disturbance of ecosystems can help prevent spread of vector-borne diseases. Regional diagnostic and treatment approaches and specific vaccines are required to avert morbidity and mortality.

Rising meningitis in USA and Mexico: insights from the fatal outbreak

Meningitis, an inflammatory disease affecting the meningeal layers of the brain and the spinal cord, poses a significant public health concern globally. Most meningitis cases are caused by viral infections, bacterial infections being the second most common cause, while fungal or parasitic infections are deemed rare. Despite the decrease in bacterial meningitis because of vaccination and treatment, a recent meningitis outbreak in the United States and Mexico highlighted ongoing challenges. The current meningitis outbreak is caused by a pathogenic fungus and is associated with surgical procedures performed under spinal anaesthesia as reported by the Centers for Disease Control and Prevention (CDC) on the 11 May of 2023. Around 20 cases with clinical suspicion of meningitis, including two fatalities, have been attributed to this rampant outbreak. Timely diagnosis, utilising diagnostic modalities such as lumbar puncture and pathogen detection methods, is crucial for appropriate management. Iatrogenic meningitis must be avoided by enhancing surveillance, infection control procedures, and adherence to aseptic practices. To lessen the effects of meningitis and enhance patient outcomes, the WHO's roadmap and preventive interventions, such as targeted immunisations, are essential.

Magnetically-targetable outer-membrane vesicles for sonodynamic eradication of antibiotic-tolerant bacteria in bacterial meningitis

Treatment of acute bacterial meningitis is difficult due to the impermeability of the blood-brain barrier, greatly limiting the antibiotic concentrations that can be achieved in the brain. Escherichia coli grown in presence of iron-oxide magnetic nanoparticles secrete large amounts of magnetic outer-membrane vesicles (OMVs) in order to remove excess Fe from their cytoplasm. OMVs are fully biomimetic nanocarriers, but can be inflammatory. Here, non-inflammatory magnetic OMVs were prepared from an E. coli strain in which the synthesis of inflammatory lipid A acyltransferase was inhibited using CRISPR/Cas9 mediated gene knockout. OMVs were loaded with ceftriaxone (CRO) and meso-tetra-(4-carboxyphenyl)porphine (TCPP) and magnetically driven across the blood-brain barrier for sonodynamic treatment of bacterial meningitis. ROS-generation upon ultrasound application of CRO- and TCPP-loaded OMVs yielded similar ROS-generation as by TCPP in solution. In vitro, ROS-generation by CRO- and TCPP-loaded OMVs upon ultrasound application operated synergistically with CRO to kill a hard-to-kill, CRO-tolerant E. coli strain. In a mouse model of CRO-tolerant E. coli meningitis, CRO- and TCPP-loaded OMVs improved survival rates and clinical behavioral scores of infected mice after magnetic targeting and ultrasound application. Recurrence did not occur for at least two weeks after arresting treatment.

The meningitis outbreak returns to Niger: Concern, efforts, challenges, and recommendations

Meningitis, a disease that commonly manifests in African meningitis belt, continues to be a public health problem as it is a fatal disease that leave survivors with long-term effects. Most cases of meningitis are due to bacterial and viral infection, although parasites, fungus, cancer, drugs, and immune disorders can rarely cause meningitis. Stiff neck, high temperature, light sensitivity, disorientation, headaches, and vomiting are the most typical symptoms of meningitis. Niger, being in African meningitis belt, has been affected by many meningitis outbreaks. Since 2015, a total of 20,789 cases and 1369 fatalities (CFR 6.6%) have been documented in Niger. In contrast to earlier seasons, the current outbreak of meningitis in Niger exhibits both an increase in the number of cases and a rise in the growth rate. A total of 559 cases of meningitis, including 18 fatalities (overall CFR 3.2%), were reported in the Zinder Region, southeast of Niger, from 1 November 2022 to 27 January 2023, compared to 231 cases reported from 1 November 2021 to 31 January 2022. In the current outbreak, the Neisseria meningitidis serogroup C (NmC) is responsible for the majority of laboratory confirmed cases (104/111; 93.7%). To organize the response to the outbreak, a global team of WHO and other partners, including MSF and UNICEF, has been sent to Niger. Even though there are many challenges in battle against meningitis in Niger, immunization, antibiotics administration and strong disease surveillance are recommended techniques to cope with the current meningitis outbreak in Niger.

Neonatal Meningitis-Causing Escherichia coli Induces Microglia Activation which Acts as a Double-Edged Sword in Bacterial Meningitis

Bacterial meningitis is a devastating disease occurring worldwide, with up to half of survivors left with permanent neurological sequelae. Neonatal meningitis-causing Escherichia coli (NMEC) is the most common Gram-negative bacillary organism that causes meningitis, particularly during the neonatal period. Here, RNA-seq transcriptional profiles of microglia in response to NMEC infection show that microglia are activated to produce inflammatory factors. In addition, we found that the secretion of inflammatory factors is a double-edged sword that promotes polymorphonuclear neutrophil (PMN) recruitment to the brain to clear the pathogens but, at the same time, induces neuronal damage, which may be related to the neurological sequelae. New neuroprotective therapeutic strategies must be developed for the treatment of acute bacterial meningitis. We found that transforming growth factor-β (TGF-β) may be a strong candidate in the treatment of acute bacterial meningitis, as it shows a therapeutic effect on bacterial-meningitis-induced brain damage. Prevention of disease and early initiation of the appropriate treatment in patients with suspected or proven bacterial meningitis are the key factors in reducing morbidity and mortality. Novel antibiotic and adjuvant treatment strategies must be developed, and the main goal for new therapies will be dampening the inflammatory response. Based on this view, our findings may help develop novel strategies for bacterial meningitis treatment.

Living with HIV and Getting Vaccinated: A Narrative Review

After 40 years of its appearance, human immunodeficiency virus (HIV) infection remains a leading public health challenge worldwide. Since the introduction of antiretroviral treatment (ART), HIV infection has become a chronic condition, and people living with HIV could have life expectancies close to those of the general population. People with HIV often have an increased risk of infection or experience more severe morbidity following exposure to vaccine-preventable diseases. Nowadays, several vaccines are available against bacteria and viruses. However, national and international vaccination guidelines for people with HIV are heterogeneous, and not every vaccine is included. For these reasons, we aimed to perform a narrative review about the vaccinations available for adults living with HIV, reporting the most updated studies performed for each vaccine among this population. We performed a comprehensive literature search through electronic databases (Pubmed-MEDLINE and Embase) and search engines (Google Scholar). We included English peer-reviewed publications (articles and reviews) on HIV and vaccination. Despite widespread use and guideline recommendations, few vaccine trials have been conducted in people with HIV. In addition, not all vaccines are recommended for people with HIV, especially for those with low CD4 cells count. Clinicians should carefully collect the history of vaccinations and patients' acceptance and preferences and regularly check the presence of antibodies for vaccine-preventable pathogens.

An Overview of Clinical Manifestations of Dermatological Disorders in Intensive Care Units: What Should Intensivists Be Aware of?

Acute skin failure is rarely the primary diagnosis that necessitates admission to an intensive care unit. Dermatological manifestations in critically ill patients, on the other hand, are relatively common and can be used to make a key diagnosis of an adverse drug reaction or an underlying systemic illness, or they may be caused by factors related to a prolonged stay or invasive procedures. In intensive care units, their classification is based on the aetiopathogenesis of the cutaneous lesion and, in the meantime, distinguishes critical patients. When evaluating dermatological manifestations, several factors must be considered: onset, morphology, distribution, and associated symptoms and signs. This review depicts dermatological signs in critical patients in order to lay out better recognition.