Central Nervous System Infection Research Articles

Childhood Health and Educational outcomes afteR perinatal Brain injury (CHERuB): protocol for a population-matched cohort study

IntroductionOver 3000 infants suffer a brain injury around the time of birth every year in England. Although these injuries can have important implications for children and their families, our understanding...

Central Nervous System Infection with Hypervirulent Klebsiella pneumoniae

Hypervirulent Klebsiella pneumoniae (hvKp) infections are being increasingly reported globally, and cause severe central nervous system (CNS) and multiorgan infections even in immunocompetent individuals. The recent emergence of hvKp antibiotic resistance has generated escalating concern about effective infection control for this potentially neuroinvasive pathogen. Herein, we report two cases of Klebsiella pneumoniae-related CNS infection, including one patient with antimicrobial-resistant hvKp, confirmed by string test that demonstrated a hypermucoviscous phenotype.

Propagation of distinct CWD prion strains during peripheral and intracerebral challenges of gene-targeted mice

Since prion diseases result from infection and neurodegeneration of the central nervous system (CNS), experimental characterizations of prion strain properties customarily rely on the outcomes of intracerebral challenges. However, natural transmission of certain prions, including those causing chronic wasting disease (CWD) in elk and deer, depends on propagation in peripheral host compartments prior to CNS infection. Using gene-targeted GtE and GtQ mice, which accurately control cellular elk or deer PrP expression, we assessed the impact that peripheral or intracerebral exposures play on CWD prion strain propagation and resulting CNS abnormalities. Whereas oral and intraperitoneal transmissions produced identical neuropathological outcomes in GtE and GtQ mice and preserved the naturally convergent conformations of elk and deer CWD prions, intracerebral transmissions generated CNS prion strains with divergent biochemical properties in GtE and GtQ mice that were changed compared to their native counterparts. While CWD replication kinetics remained constant during iterative peripheral transmissions and brain titers reflected those found in native hosts, serial intracerebral transmissions produced 10-fold higher prion titers and accelerated incubation times. Our demonstration that peripherally and intracerebrally challenged Gt mice develop dissimilar CNS diseases which result from the propagation of distinct CWD prion strains points to the involvement of tissue-specific cofactors during strain selection in different host compartments. Since peripheral transmissions preserved the natural features of elk and deer prions, whereas intracerebral propagation produced divergent strains, our findings illustrate the importance of experimental characterizations using hosts that not only abrogate species barriers but also accurately recapitulate natural transmission routes of native strains.

Rare Central nervous system infection by Chryseobacterium indologenes diagnosed using metagenomic next-generation sequencing.

Rare Central nervous system infection by Chryseobacterium indologenes diagnosed using metagenomic next-generation sequencing.

Candida parapsilosis intracerebral abscess and intralesional amphotericin B: a novel treatment approach to a rare infection. Illustrative case.

Candida parapsilosis has been implicated in central nervous system (CNS) infections (i.e., meningitis or ventriculitis) but has not been previously reported to cause intracerebral abscesses. CNS infections secondary to C. parapsilosis are notoriously difficult to treat due to the poor CNS penetration of amphotericin B. Historically, intraventricular amphotericin B has been used to treat C. parapsilosis ventriculitis. A 15-year-old female with no comorbidities presented with nonresolving headaches, photophobia, fevers, and meningism. Computed tomography (CT) of the brain revealed a right frontal abscess. After multiple drainage surgeries, subsequent CT scans showed reaccumulation of her abscess. C. parapsilosis was cultured, and the patient was then taken to the operating room where an external ventricular drain catheter was successfully placed within the abscess cavity. Pus was repeatedly aspirated, followed by the instillation of intralesional amphotericin B twice a day for 2 weeks. The patient's clinical condition improved substantially with complete resolution of symptoms, improvement of infective markers, and resolution of radiological features of the abscess. Follow-up of the patient revealed the absence of symptoms and image characteristics of abscess on CT 3 months posttreatment. Intralesional amphotericin B is a novel but effective treatment of C. parapsilosis intracerebral abscess, an organism not previously described as a cause of intracerebral abscesses. https://thejns.org/doi/10.3171/CASE2484.

Subdural Empyema as a Rare Complication Caused by Neisseria meningitidis B

Subdural empyema (SDE) is an intracranial collection of purulent material located between the dura and the arachnoid mater. It is a serious central nervous system infection which can cause neurological sequelae and high mortality. We report one of the rare cases of SDE secondary to Neisseria meningitidis to underline the interest of evoking this diagnosis especially in patients not responding to standard antimicrobial therapy.

Clinical application and evaluation of metagenomic next-generation sequencing in pathogen detection for suspected central nervous system infections

Central nervous system Infections (CNSIs) is a disease characterized by complex pathogens, rapid disease progression, high mortality rate and high disability rate. Here, we evaluated the clinical value of metagenomic next generation sequencing (mNGS) in the diagnosis of central nervous system infections and explored the factors affecting the results of mNGS. We conducted a retrospective study to compare mNGS with conventional methods including culture, smear and etc. 111 suspected CNS infectious patients were enrolled in this study, and clinical data were recorded. Chi-square test were used to evaluate independent binomial variables, taking p < 0.05 as statistically significant threshold. Of the 111 enrolled cases, 57.7% (64/111) were diagnosed with central nervous system infections. From these cases, mNGS identified 39.6% (44/111) true-positive cases, 7.2% (8/111) false-positive case, 35.1% (39/111) true-negative cases, and 18.0% (20/111) false-negative cases. The sensitivity and specificity of mNGS were 68.7% (44/64) and 82.9% (39/47), respectively. Compared with culture, mNGS provided a higher pathogen detection rate in CNSIs patients (68.7% (44/64) vs. 26.5% (17/64), p < 0.0001). Compared to conventional methods, positive percent agreement and negative percent agreement was 84.60% (44/52) and 66.1% (39/59) separately. At a species-specific read number (SSRN) ≥ 2, mNGS performance in the diagnosis of definite viral encephalitis and/or meningitis was optimal (area under the curve [AUC] 0.758, 95% confidence interval [CI] 0.663–0.854). In bacterial CNSIs patients with significant CSF abnormalities (CSF WBC > 300*106/L), the positive rate of CSF mNGS is higher. To sum up, conventional microbiologic testing is insufficient to detect all neuroinvasive pathogens, and mNGS exhibited satisfactory diagnostic performance in CNSIs and with an overall detection rate higher than culture (p < 0.0001).

Metagenomic next-generation sequencing of cerebrospinal fluid reveals etiological and microbiological features in patients with various central nervous system infections.

The application of metagenomic next-generation sequencing (mNGS) in pathogens detection of cerebrospinal fluid (CSF) is limited because clinical, microbiological, and biological information are not well connected. We analyzed the 428 enrolled patients' clinical features, pathogens diagnostic efficiency of mNGS in CSF, microbial community structure and composition in CSF, and correlation of microbial and clinical biomarkers in CSF. General characteristics were unspecific but helpful in formulating a differential diagnosis. CSF mNGS has a higher detection rate (34.6%) compared to traditional methods (5.4%). mNGS detection rate was higher when the time from onset to CSF collection was ≤20 days, the CSF leukocytes count was >200 × 106/L, the CSF protein concentration was >1.3 g/L, or CSF glucose concentration was ≤2.5 mmol/L in non-postoperative bacterial CNS infections (CNSi). CSF was not strictly a sterile environment, and the potential pathogens may contribute to the dysbiosis of CSF microbiome. Furthermore, clinical biomarkers were significantly relevant to CNS pathogens. Clinical data are helpful in choosing a proper opportunity to obtain an accurate result of mNGS, and can speculate whether the mNGS results are correct or not. Our study is a pioneering study exploring the CSF microbiome in different CNSIs.

Electrochemically synthesized nanostructured gold-bismuth as novel sensor for efficient determination of cefotaxime in aqueous media

Antibiotics are crucial due to their widespread use in human and veterinary medicine. Cefotaxime, a third-generation cephalosporin, prevents bacterial production and treats central nervous system infections like meningitis and septicemia. This study developed a novel electrochemical sensor for detecting Cefotaxime (CFTX) by electrodepositing gold-bismuth nanoparticles (Au-Bi NPs) on a carbon paste electrode (CPE). The electrochemical parameters were optimized for the successful deposition of Au-BiNPs. Morphological and X-ray diffraction (XRD) analyses revealed nanoparticle clusters of cubic Au and stacked monoclinic BiNPs on the CPE surface, with crystallite sizes of 7.5 and 6.3 nm, respectively. Cyclic voltammetry (CV) showed that the sensor had superior electrochemical activity for CFTX oxidation compared to bare CPE, BiNPs/CPE, and AuNPs/CPE, mainly due to the synergetic effect of Au-Bi nanoparticles. Electrochemical impedance spectroscopy (EIS) indicated minimal resistance to electron transfer at Au-BiNPs/CPE. Voltammetric investigations revealed a diffusion-controlled electrooxidation process involving two protons and two electrons, influenced by solution pH and scan rate. The sensor displayed excellent analytical parameters for CFTX detection, including a wide linear range (0.5 μM to 20 μM), high sensitivity (4.55 μAμM−1 cm−2), and a low detection limit (0.094 μM). Density Functional Theory (DFT) calculations provided theoretical insights into the sensor’s performance. The sensor also showed excellent reproducibility, repeatability (RSD values of 3.74 % and 1.71 %, respectively), and long-term stability of about one month, offering a new method for accurate and sensitive CFTX detection.

Comparison of infection risk between enzalutamide and abiraterone in patients with prostate cancer.

Enzalutamide and abiraterone may differ in their immunomodulatory effects, and the prednisone coadministered with abiraterone can be immunosuppressive. This study aimed to compare the risk of different types of infection in patients with prostate cancer receiving enzalutamide or abiraterone in combination with androgen deprivation therapy. Patients with prostate cancer receiving enzalutamide or abiraterone in addition to androgen deprivation therapy in Hong Kong between December 1999 to March 2021 were identified in this retrospective cohort study and followed up until September 2021, death, or crossover. Outcomes, including any sepsis, pneumonia, urinary tract infection, cellulitis or skin abscess, central nervous system infections, and tuberculosis, were analyzed as both time-to-event outcomes (multivariable Fine-Gray regression, with mortality considered a competing event) and recurrent-event outcomes (multivariable negative binomial regression). Altogether, 1582 patients were analyzed (923 abiraterone users; 659 enzalutamide users) with a median follow-up of 10.6 months (interquartile range: 5.3-19.9 months). Compared to abiraterone users, enzalutamide users had lower cumulative incidences of sepsis (adjusted subhazard ratio [SHR] 0.70 [0.53-0.93], p=.014), pneumonia (adjusted SHR 0.76 [0.59-0.99], p=.040), and cellulitis or skin abscess (adjusted SHR 0.55 [0.39-0.79], p=.001), but not urinary tract infection (adjusted SHR 0.91 [0.62-1.35], p=.643). Associations between exposure and central nervous system infections and tuberculosis were not assessed because of low event rates. Analyzing the outcomes as recurrent events gave similar results. Enzalutamide use may be associated with a lower risk of urinary tract infection in patients with diabetes mellitus. Compared to abiraterone users, enzalutamide users have significantly lower risks of sepsis, pneumonia, cellulitis, or skin abscess.

Evaluation of the Bio-Speedy Meningitis/Encephalitis Panel in the Diagnosis of Central Nervous System Infections

Infections of the central nervous system (CNS) can lead to severe outcomes if not accurately diagnosed and treated. The broad spectrum of pathogens involved in CNS infections can make diagnosis challenging. Polymerase chain reaction (PCR) -based multiplex molecular diagnostic panels can rapidly and simultaneously detect multiple neuropathogens in cerebrospinal fluid (CSF). This study was aimed to assess the Bio-Speedy Meningitis/Encephalitis RT-PCR MX-17 panel (Bioeksen, İstanbul, Türkiye), a novel multiplex PCR test, in diagnosing CNS infections. The panel can detect a range of pathogens, including Escherichia coli K1, Haemophilus influenzae, Listeria monocytogenes, Neisseria meningitidis, Streptococcus pneumoniae, Streptococcus agalactiae, enterovirus (EV), herpes simplex virus (HSV) 1 and 2, HHV-6, HHV-7, HHV-8, human parechovirus (HPeV), varicella zoster virus (VZV), cytomegalovirus (CMV) and Cryptococcus gatti/neoformans in CSF samples. This retrospective study included 128 CSF samples from 128 patients sent to Bursa Uludağ University Health Application and Research Center Microbiology Laboratory between June 2022 and July 2023 to search for CNS infectious agents. Patient clinical, radiological and laboratory data were collected from the Hospital Information Record System (HIRS). Bacterial pathogens were identified through culture, while viral pathogens were detected in CSF samples using the Fast Track Diagnostics (FTD) multiplex RT-PCR panel (Fast Track Diagnostics Ltd., Luxembourg) for HSV-1, HSV-2, VZV, EV, mumps virus and HPeV. The stored CSF samples were then tested using the BioSpeedy panel and the results were compared with those of the culture and the FTD panel. Pathogens that were detected were considered positive if they were consistent with the patient's symptoms and CSF characteristics according to infectious disease and pediatric infectious disease specialists. Pathogens detected but not supported by the patient's symptoms and CSF characteristics were classified as uncertain clinical relevance (UCR). Out of the 128 patients tested for CNS infectious agents, 44 (34.4%) were diagnosed with a CNS infection. The overall pathogen detection rate with all methods was 43.2% (19/44). The Bio-Speedy panel identified pathogens in 29.5% (13/44) of the patients, followed by the FTD panel (20.5%, 9/44) and culture (9.1%, 4/44). Four bacteria were identified with culture, three of which were also detected by the Bio-Speedy panel. Additionally, six bacteria were identified with Bio-Speedy panel, that were not identified by culture. The FTD panel identified nine viruses, four of which were also identified by Bio-Speedy. In total, the Bio-Speedy panel detected 13 of the 19 positive pathogens (nine bacteria and four viruses: [S.pneumoniae (n= 3), VZV (n= 3), N.meningitidis (n= 2), H.influenzae (n= 2), L.monocytogenes (n= 1), E.coli (n= 1) ve EV (n= 1)]. However, the Bio-Speedy panel identified 15 pathogens [S.pneumoniae (n= 1), E.coli (n= 1), C.gatti/neoformans (n= 1), CMV (n= 8), HHV-6 (n= 3) ve HHV-7 (n= 1)] considered as UCR. The Bio-Speedy identified the causative pathogens in the highest percentage (29.5%) of patients with confirmed CNS infections. Nevertheless, test results should be interpreted based on patient characteristics to ensure appropriate patient management. Using multiple methods and multiplex tests may improve diagnostic accuracy for CNS infections.

Brainstorm: A case of granulomatous encephalitis

Background: Free-living amoebas (FLAs) can cause severe and fatal central nervous system infections that are difficult to diagnose. Methods: We present the case of a 74-year-old immunocompetent woman admitted for focal neurological symptoms with enhancing lesions in the right cerebellar hemisphere. A first cerebral biopsy showed granulomatous inflammation, but no microorganisms were identified. After transient clinical improvement, she eventually deteriorated 4 months after initial presentation, with an MRI confirming multiple new masses affecting all cerebral lobes. Results: A second brain biopsy revealed granulomatous and acute inflammation with organisms containing a large central nucleus with prominent karyosome, consistent with FLAs. Immunohistochemical and polymerase chain reaction assays performed at CDC were positive for Acanthamoeba spp, confirming the diagnosis of granulomatous amoebic encephalitis (GAE) caused by Acanthamoeba spp. The patient was treated with combination therapy recommended by CDC, but died a few days later. Upon histopathological rereview, amoebic cysts and trophozoites were identified by histochemical and immunohistochemical methods in the first cerebral biopsy. Conclusion: FLA infections can be challenging to diagnose because of the low incidence, non-specific clinical and radiological presentation, lack of accessible diagnostic tools, and clinicians’ unfamiliarity. This case highlights the importance of recognizing FLA as a potential cause of granulomatous encephalitis, even in the absence of risk factors, as early treatment might be associated with favourable outcomes in case reports. When suspected, CDC laboratories offer tests to confirm the diagnosis promptly.

Fosfomycin-Containing Regimens for the Treatment of Central Nervous System Infections in a Neonatal Intensive Care Unit: A Case Series Study.

Central nervous system infections are among the most severe infectious conditions in the neonatal period and are still burdened by significant mortality, especially in preterm infants and those with a low birth weight or other comorbidities. In this study, we examined the role of fosfomycin-containing antibiotic regimens in neonates with central nervous system infections. We included six neonates over a period of five years: four with meningitis and two with cerebral abscesses. All patients underwent fosfomycin therapy after failing first-line antibiotic regimens. Of the six neonates, two died; two developed neurological and psychomotor deficits and two recovered uneventfully. None of the neonates experienced adverse reactions to fosfomycin, confirming the safety of the molecule in this population. In conclusion, the deep penetration in the central nervous system, the unique mechanism of action, the synergy with other antibiotic therapies, and the excellent safety profile all make fosfomycin an attractive drug for the treatment of neonatal central nervous system infections.

Clinical approach to donor-derived infection in solid organ transplant recipients.

Donor-derived infection is an uncommon but potentially devastating complication of solid organ transplantation (SOT). Accurate and timely identification of unexpected infectious disease transmission events has implications not only for the recipient(s) experiencing infection, but also other recipients of organs or tissues from the same donor who may require additional testing or risk mitigation, as well as the broader organ transplant regulatory framework. This narrative review synthesizes data from published reports of symptomatic unexpected donor-derived infections in SOT recipients to provide clinicians with a systematic approach to the evaluation of undifferentiated illnesses that may be of donor origin. Key reasons to consider donor-derived infection include certain microbiologically proven infections in the recipient, especially early after transplant, characteristics of the donor or their management that suggest potential exposure to or infection with specific pathogens prior to organ procurement, and select clinical syndromes that occur in the post-transplant period. Syndromes for which expedited consideration and evaluation of donor-derived infection may be warranted include central nervous system infection, graft or perigraft complications developing in the absence of typical risk factors, and unexplained critical illness/sepsis syndrome in the early post-transplant period. When embarking on an investigation of a suspected donor-derived infection, clinicians should apply knowledge of the entire continuum of the organ procurement and transplant process to ensure unbiased and comprehensive data collection that will facilitate appropriate adjudication of these uncommon but high-consequence events.

Clinical Metagenomic Next-Generation Sequencing for Diagnosis of Central Nervous System Infections: Advances and Challenges.

Central nervous system (CNS) infections carry a substantial burden of morbidity and mortality worldwide, and accurate and timely diagnosis is required to optimize management. Metagenomic next-generation sequencing (mNGS) has proven to be a valuable tool in detecting pathogens in patients with suspected CNS infection. By sequencing microbial nucleic acids present in a patient's cerebrospinal fluid, brain tissue, or samples collected outside of the CNS, such as plasma, mNGS can detect a wide range of pathogens, including rare, unexpected, and/or fastidious organisms. Furthermore, its target-agnostic approach allows for the identification of both known and novel pathogens. This is particularly useful in cases where conventional diagnostic methods fail to provide an answer. In addition, mNGS can detect multiple microorganisms simultaneously, which is crucial in cases of mixed infections without a clear predominant pathogen. Overall, clinical mNGS testing can help expedite the diagnostic process for CNS infections, guide appropriate management decisions, and ultimately improve clinical outcomes. However, there are key challenges surrounding its use that need to be considered to fully leverage its clinical impact. For example, only a few specialized laboratories offer clinical mNGS due to the complexity of both the laboratory methods and analysis pipelines. Clinicians interpreting mNGS results must be aware of both false negatives-as mNGS is a direct detection modality and requires a sufficient amount of microbial nucleic acid to be present in the sample tested-and false positives-as mNGS detects environmental microbes and their nucleic acids, despite best practices to minimize contamination. Additionally, current costs and turnaround times limit broader implementation of clinical mNGS. Finally, there is uncertainty regarding the best practices for clinical utilization of mNGS, and further work is needed to define the optimal patient population(s), syndrome(s), and time of testing to implement clinical mNGS.

Difficulty in diagnosing intracranial infection caused by Mycobacterium avium in an AIDS patient: case report and review of the literature

BackgroundMycobacterium avium complex (MAC) is an uncommon clinical pathogen, especially in the central nervous system (CNS), and carries a poor prognosis. MAC infections commonly present as immune reconstitution disease (IRD) in HIV patients. Herein, we report a case of intracranial infection caused by MAC in an AIDS patient without disseminated MAC (DMAC) and immune reconstitution inflammatory syndrome (IRIS).Case presentationA 31-year-old HIV-positive male presented us with progressively worsening CNS symptoms, and neuroimaging revealed ring-enhancing lesions. The intracranial lesions worsened after the empirical therapy for toxoplasma encephalitis and fungal infection. Due to the rapid progression of the disease, the patient died. Mycobacterium avium was the only pathogen in brain tissue after cultures and molecular biology tests.ConclusionMAC infection in CNS is challenging to diagnose in HIV patients. Our findings emphasize that obtaining tissue samples and applying molecular biology methods is essential to help diagnose the patient as soon as possible to receive adequate treatment.

Measuring the Direct Medical Costs of Hospital-Onset Infections Using an Analogy Costing Framework.

The majority of recent estimates on the direct medical cost attributable to hospital-onset infections (HOIs) has focused on device- or procedure-associated HOIs. The attributable costs of HOIs that are not associated with device use or procedures have not been extensively studied. We developed simulation models of attributable cost for 16 HOIs and estimated the total direct medical cost, including nondevice-related HOIs in the USA for 2011 and 2015. We used total discharge costs associated with HOI-related hospitalization from the National Inpatient Sample and applied an analogy costing methodology to develop simulation models of the costs attributable to HOIs. The mean attributable cost estimate from the simulation analysis was then multiplied by previously published estimates of the number of HOIs for 2011 and 2015 to generate national estimates of direct medical costs. After adjusting all estimates to 2017 US dollars, attributable cost estimates for select nondevice-related infections attributable cost estimates ranged from $7661 for ear, eye, nose, throat, and mouth (EENTM) infections to $27,709 for cardiovascular system infections in 2011; and from $8394 for EENTM to $26,445 for central nervous system infections in 2016 (based on 2015 incidence data). The national direct medical costs for all HOIs were $14.6 billion in 2011 and $12.1 billion in 2016. Nondevice- and nonprocedure-associated HOIs comprise approximately 26-28% of total HOI costs. Results suggest that nondevice- and nonprocedure-related HOIs result in considerable costs to the healthcare system.

Targeted metabolomics identifies accurate CSF metabolite biomarkers for the differentiation between COVID-19 with neurological involvement and CNS infections with neurotropic viral pathogens

BackgroundCOVID-19 is primarily considered a respiratory tract infection, but it can also affect the central nervous system (CNS), which can result in long-term sequelae. In contrast to CNS infections by classic neurotropic viruses, SARS-CoV-2 is usually not detected in cerebrospinal fluid (CSF) from patients with COVID-19 with neurological involvement (neuro-COVID), suggesting fundamental differences in pathogenesis.MethodsTo assess differences in CNS metabolism in neuro-COVID compared to CNS infections with classic neurotropic viruses, we applied a targeted metabolomic analysis of 630 metabolites to CSF from patients with (i) COVID-19 with neurological involvement [n = 16, comprising acute (n = 13) and post-COVID-19 (n = 3)], (ii) viral meningitis, encephalitis, or myelitis (n = 10) due to herpes simplex virus (n = 2), varicella zoster virus (n = 6), enterovirus (n = 1) and tick-borne encephalitis virus (n = 1), and (iii) aseptic neuroinflammation (meningitis, encephalitis, or myelitis) of unknown etiology (n = 21) as additional disease controls.ResultsStandard CSF parameters indicated absent or low neuroinflammation in neuro-COVID. Indeed, CSF cell count was low in neuro-COVID (median 1 cell/µL, range 0–12) and discriminated it accurately from viral CNS infections (AUC = 0.99) and aseptic neuroinflammation (AUC = 0.98). 32 CSF metabolites passed quality assessment and were included in the analysis. Concentrations of differentially abundant (fold change ≥|1.5|, FDR ≤ 0.05) metabolites were both higher (9 and 5 metabolites) and lower (2 metabolites) in neuro-COVID than in the other two groups. Concentrations of citrulline, ceramide (d18:1/18:0), and methionine were most significantly elevated in neuro-COVID. Remarkably, triglyceride TG(20:1_32:3) was much lower (mean fold change = 0.09 and 0.11) in neuro-COVID than in all viral CNS infections and most aseptic neuroinflammation samples, identifying it as highly accurate biomarker with AUC = 1 and 0.93, respectively. Across all samples, TG(20:1_32:3) concentration correlated only moderately with CSF cell count (ρ = 0.65), protein concentration (ρ = 0.64), and Q-albumin (ρ = 0.48), suggesting that its low levels in neuro-COVID CSF are only partially explained by less pronounced neuroinflammation.ConclusionsThe results suggest that CNS metabolite responses in neuro-COVID differ fundamentally from viral CNS infections and aseptic neuroinflammation and may be used to discover accurate diagnostic biomarkers in CSF and to gain insights into differences in pathophysiology between neuro-COVID, viral CNS infections and aseptic neuroinflammation.

A case report and literature review: Mycobacterium leprae infection diagnosed by metagenomic next-generation sequencing of cerebrospinal fluid

BackgroundLeprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae) that is responsible for deformities and irreversible peripheral nerve damage and has a broad spectrum of clinical and serological manifestations. Leprosy primarily affects the peripheral nerves and rarely presents with central nervous system involvement. Diagnosing leprosy can still be difficult in some cases, especially when the infection involves uncommon clinical manifestations and extracutaneous sites. Delayed diagnosis and treatment of leprosy may lead to irreversible damage and death.Case PresentationWe report a case of a 30-year-old female presenting with “repeated high fever with symptoms of headache for 14 days”. On the day of admission, physical signs of lost eyebrows and scattered red induration patches all over her body were observed. The patient’s diagnosis was based on the clinical characteristics using a combination of metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) and slit-skin smear. After confirming Listeria meningitis and multibacillary leprosy with erythema nodosum leprosum (ENL), a type 2 reaction, she was treated with ampicillin sodium, dapsone, rifampicin, clofazimine, methylprednisolone, and thalidomide. At the 1-year follow-up, the frequency and severity of headaches have significantly decreased and a good clinical response with improved skin lesions was found.ConclusionThis case highlights the importance of considering leprosy, which is a rare and underrecognized disease, in the differential diagnosis of skin rashes with rheumatic manifestations, even in areas where the disease is not endemic, and physicians should be alerted about the possibility of central nervous system infections. In addition, mNGS can be used as a complementary diagnostic tool to traditional diagnostic methods to enhance the diagnostic accuracy of leprosy.

Host and fungal factors both contribute to cryptococcosis-associated hyperammonemia (cryptammonia).

Cryptococcus neoformans and Cryptococcus gattii are both known urease producers and have the potential to cause hyperammonemia. We hypothesized that the risk of hyperammonemia is increased by renal failure, burden of cryptococcal infection, and fungal strain characteristics. We performed a retrospective review of plasma ammonia levels in patients with cryptococcal infections. Risk factors for hyperammonemia were statistically compared between patients with and without hyperammonemia (>53 µmol/L). Cryptococcal cells from three patients included in the study were recovered from our biorepository. Strain characteristics including urease activity, ammonia production, growth curves, microscopy, melanin production, and M13 molecular typing were analyzed and compared with a wild-type (WT) C. neoformans strain. We included 29 patients, of whom 37.9% had hyperammonemia, 59% had disseminated cryptococcal infection (DCI), and 41% had isolated central nervous system infection. Thirty-eight percent of patients had renal failure and 28% had liver disease. Renal failure was associated with 4.4 times (95% confidence interval [CI] 1.5, 13.0) higher risk of hyperammonemia. This risk was higher in DCIs (RR 6.2, 95% CI 1.0, 40.2) versus isolated cryptococcal meningitis (RR 2.5, 95% CI, 0.40, 16.0). Liver disease and cryptococcal titers were not associated with hyperammonemia. C. neoformans from one patient with extreme hyperammonemia demonstrated a 4- to 5-fold increase in extracellular urease activity, slow growth, enlarged cell size phenotypes, and diminished virulence factors. Hyperammonemia was strongly associated with renal failure in individuals with DCI, surpassing associations with liver failure or cryptococcal titers. However, profound hyperammonemia in one patient was attributable to high levels of urease secretion unique to that cryptococcal strain. Prospective studies are crucial to exploring the significance of this association.IMPORTANCECryptococcus produces and secretes the urease enzyme to facilitate its colonization of the host. Urease breaks down urea into ammonia, overwhelming the liver's detoxification process and leading to hyperammonemia in some hosts. This underrecognized complication exacerbates organ dysfunction alongside the infection. Our study investigated this intricate relationship, uncovering a strong association between the development of hyperammonemia and renal failure in patients with cryptococcal infections, particularly those with disseminated infections. We also explore mechanisms underlying increased urease activity, specifically in strains associated with extreme hyperammonemia. Our discoveries provide a foundation for advancing research into cryptococcal metabolism and identifying therapeutic targets to enhance patient outcomes.