Mass Spectrometry Identifies Taenia solium Proteins in Sera of Patients With and Without Parenchymal Neurocysticercosis.

Neurocysticercosis (NCC), a major cause of global acquired epilepsy, results from Taenia solium larval brain infection. T. solium adult worms release large numbers of infective eggs into the environment contributing to high levels of exposure in endemic areas. This study identifies T. solium proteins in the sera of individuals with and without NCC using mass spectrometry to examine exposure in endemic regions. Forty-seven patients (18-51 years), 24 parenchymal NCC (pNCC), 8 epilepsy of unknown aetiology, 7 glioma, 8 brain tuberculoma, and 7 healthy volunteers were studied. Trypsin digested sera were subject to liquid chromatography-tandem mass spectrometry and spectra of 375-1700 m/z matched against T. solium WormBase ParaSite database with MaxQuant software to identify T. solium proteins. Three hundred and nineteen T. solium proteins were identified in 87.5% of pNCC and 56.6% of non-NCC subjects. Three hundred and four proteins were exclusive to pNCC sera, seven to non-NCC sera and eight in both. Ten percent, exhibiting immune-modulatory properties, originated from the oncosphere and cyst vesicular fluid. In conclusion, in endemic regions, T. solium proteins are detected in sera of individuals with and without pNCC. The immunomodulatory nature of these proteins may influence susceptibility and course of infection.

Influenza virus infection exacerbates gene expression related to neurocognitive dysfunction in brains of old mice.

BACKGROUND: Age > 65 years is a key risk factor for poor outcomes after human influenza infection. Specifically, in addition to respiratory disease, non-neurotropic influenza A virus (IAV) causes neuro-cognitive complications, e.g. new onset depression and increases the risk of dementia after hospitalization. This study aimed to identify potential mechanisms of these effects by determining differences between young and old mice in brain gene expression in a mouse model of non-neurotropic IAV infection. METHODS: Young (12 weeks) and old (70 weeks) C57Bl/6J mice were inoculated intranasally with 200 PFU H1N1 A/PR/34/8 (PR8) or sterile PBS (mock). Gene expression in lung and brain was measured by qRT-PCR and normalized to ß-actin. Findings were confirmed using the nCounter Mouse Neuroinflammation Array (NanoString) and analyzed with nSolver 4.0 and Ingenuity Pathway Analysis (IPA, Qiagen). RESULTS: IAV PR8 did not invade the central nervous system. Young and old mice differed significantly in brain gene expression at baseline and during non-neurotropic IAV infection. Expression of brain Ifnl, Irf7, and Tnf mRNAs was upregulated over baseline control at 3 days post-infection (p.i.) only in young mice, but old mice expressed more Ifnl than young mice 7 days p.i. Gene arrays showed down-regulation of the Epigenetic Regulation, Insulin Signaling, and Neurons and Neurotransmission pathways in old mice 3 days p.i. while young mice demonstrated no change or induction of these pathways at the same time point. IPA revealed marked baseline differences between old and young mice. Gene expression related to Cognitive Impairment, Memory Deficits and Learning worsened in old mice relative to young mice during IAV infection. Aged mice demonstrate more severe changes in gene expression related to memory loss and cognitive dysfunction by IPA. CONCLUSIONS: These data suggest the genes and pathways related to learning and cognitive performance that were worse at baseline in old mice were further worsened by IAV infection, similar to old patients. Early events in the brain triggered by IAV infection portend downstream neurocognitive pathology in old adults.

The diagnostic dilemma for atypical presentation of progressive human Mpox.

BACKGROUND: Human mpox has increasingly been reported worldwide since May 2022, with higher incidence in men who have sex with men (MSM) and persons living with HIV (PLHIV) with presentation typical for generalized macules and papules. CASE PRESENTATION: We are describing a case of human mpox, which presented as widespread, atypical round verrucous lesions that went undiagnosed in the community for six months and was treated with antibacterials and antifungals given the similarity to skin manifestations associated with endemic mycoses. CONCLUSIONS: Suspicion for human mpox should be high in young MSM and PLHIV who present with rash and mpox should be ruled out earlier.

Systemic Listeria monocytogenes infection in aged mice induces long-term neuroinflammation: the role of miR-155.

BACKGROUND: Understanding mechanisms of pathologic neuroinflammation is essential for improving outcomes after central nervous system infections. Brain tissue-resident memory T cells (bTRM) are recruited during central nervous system infection and promote pathogen control as well as noxious inflammation. Our prior studies in young mice showed optimal recruitment of CD8+ bTRM during neuroinvasive Listeria monocytogenes (Lm) infection required miR-155, and was significantly inhibited by anti-miR-155 oligonucleotides. Since Lm is an important pathogen in the elderly, we hypothesized anti-miR-155 would also inhibit accumulation of CD8+ bTRM in aged mice infected with Lm. METHODS: Young (2 mo) and aged (> 18 mo) male C57BL/6 mice were infected intra-peritoneally with wild-type Lm, or avirulent Lm mutants lacking the genes required for intracellular motility (ΔactA) or phagosomal escape (Δhly), then were given antibiotics. Brain leukocytes and their intracellular cytokine production were quantified by flow cytometry >28d post-infection (p.i.). The role of miR-155 was tested by injecting mice with anti-miR-155 or control oligonucleotides along with antibiotics. RESULTS: Aged mice had significantly more homeostatic CD8+ bTRM than did young mice, which did not increase after infection with wild-type Lm despite 50% mortality, whereas young mice suffered no mortality after a larger inoculum. For direct comparison of post-infectious neuroinflammation after the same inoculum, young and aged mice were infected with 107 CFU ΔactA Lm. This mutant caused no mortality and significantly increased CD8+ bTRM 28d p.i. in both groups, whereas bone marrow-derived myeloid cells, particularly neutrophils, increased only in aged mice. Notably, anti-miR-155 reduced accumulation of brain myeloid cells in aged mice after infection, whereas CD8+ bTRM were unaffected. CONCLUSIONS: Systemic infection with Lm ΔactA is a novel model for studying infection-induced brain inflammation in aged mice without excessive mortality. CD8+ bTRM increase in both young and aged mice after infection, whereas only in aged mice bone marrow-derived myeloid cells increase long-term. In aged mice, anti-miR-155 inhibits brain accumulation of myeloid cells, but not CD8+ bTRM. These results suggest young and aged mice differ in manifestations and mechanisms of infection-induced neuroinflammation and give insight for developing therapies to ameliorate brain inflammation following severe infection in the elderly.

Misclassification Error-Adjusted Prevalence of Injection Drug Use Among Infective Endocarditis Hospitalizations in the United States: A Serial Cross-Sectional Analysis of the 2007-2016 National Inpatient Sample.

Administrative health databases have been used to monitor trends in infective endocarditis hospitalization related to nonprescription injection drug use (IDU) using International Classification of Diseases (ICD) code algorithms. Because no ICD code for IDU exists, drug dependence and hepatitis C virus (HCV) have been used as surrogate measures for IDU, making misclassification error (ME) a threat to the accuracy of existing estimates. In a serial cross-sectional analysis, we compared the unadjusted and ME-adjusted prevalences of IDU among 70,899 unweighted endocarditis hospitalizations in the 2007-2016 National Inpatient Sample. The unadjusted prevalence of IDU was estimated with a drug algorithm, an HCV algorithm, and a combination algorithm (drug and HCV). Bayesian latent class models were used to estimate the median IDU prevalence and 95% Bayesian credible intervals and ICD algorithm sensitivity and specificity. Sex- and age group-stratified IDU prevalences were also estimated. Compared with the misclassification-adjusted prevalence, unadjusted estimates were lower using the drug algorithm and higher using the combination algorithm. The median ME-adjusted IDU prevalence increased from 9.7% (95% Bayesian credible interval (BCI): 6.3, 14.8) in 2008 to 32.5% (95% BCI: 26.5, 38.2) in 2016. Among persons aged 18-34 years, IDU prevalence was higher in females than in males. ME adjustment in ICD-based studies of injection-related endocarditis is recommended.

Neuroinvasive Listeria monocytogenes infection triggers accumulation of brain CD8+ tissue-resident memory T cells in a miR-155-dependent fashion.

BACKGROUND: Brain inflammation is a key cause of cognitive decline after central nervous system (CNS) infections. A thorough understanding of immune responses to CNS infection is essential for developing anti-inflammatory interventions that improve outcomes. Tissue-resident memory T cells (TRM) are non-recirculating memory T cells that provide surveillance of previously infected tissues. However, in addition to protecting the brain against reinfection, brain TRM can contribute to post-infectious neuroinflammation. We hypothesized that accumulation of CD8+ TRM in the brain could be reduced by inhibiting microRNA (miR)-155, a microRNA that influences development of cytotoxic CD8+ T lymphocytes during infection. METHODS: C57BL/6J mice were infected by intraperitoneal injection with a lethal inoculum of Listeria monocytogenes (Lm) then treated with antibiotics. Flow cytometry was used to quantify specific populations of brain leukocytes 28-29 days (d) post-infection (p.i.). To test the degree to which miR-155 altered leukocyte influxes into the brain, infected mice were injected with a miR-155 inhibitor or locked nucleic acid (LNA) scramble control 2d, 4d, 6d, and 8d p.i. along with antibiotic treatment. Bacterial loads in spleen and liver and body weights were measured up to 7d p.i. Brain leukocytes were analyzed 14d and 28d p.i. Confirmatory studies were performed in mutated mice lacking miR-155 (miR-155-/-) RESULTS: Lm infection significantly increased the numbers of brain CD3+CD8+ lymphocytes at 28d p.i. These cells were extravascular, and displayed markers characteristic of TRM, with the predominant phenotype of CD44+CD62L-CD69+CX3CR1-. Further analysis showed that > 75% of brain TRM also expressed CD49a, PD-1, Ly6C, CD103, and CD127. Mice injected with miR-155 inhibitor lost less weight through 7d p.i. than did control mice, whereas bacterial loads in brain, liver, and spleen were not different from controls. By 28d p.i., the numbers of brain CD8+ TRM cells were significantly decreased in mice treated with the inhibitor compared with controls. Similarly, miR-155-/- mice showed significantly reduced numbers of brain CD8+ TRM cells by 28d p.i. CONCLUSIONS: Brain CD8+ TRM populations are established during neuroinvasive Lm infection. Accumulation of brain CD8+ TRM cells is reduced by blocking miR-155 and in miR-155-/- mice, indicating that this molecule has a critical role in development of these specialized cells. Administering anti-miR-155 during infection could provide a novel avenue for reducing post-infectious neuroinflammation.

Vaccine strain Listeria monocytogenes bacteremia occurring 31 months after immunization.

BACKGROUND: Listeria monocytogenes is a food-borne, facultative intracellular bacterium that causes severe diseases such as sepsis and meningoencephalitis in immunocompromised hosts. Because it stimulates robust T-lymphocyte-mediated responses, attenuated L. monocytogenes are candidate vaccine vectors for tumor immunotherapy. CASE: We report a case of bacteremia caused by vaccine strain L. monocytogenes (Axalimogene filolisbac) occurring 31 months after immunization against human papilloma virus (HPV) associated cervical cancer. CONCLUSION: Receipt of a L. monocytogenes-based vaccine is a novel risk factor for delayed L. monocytogenes bacteremia.

Distinguishing neurocysticercosis epilepsy from epilepsy of unknown etiology using a minimal serum mass profiling platform.

Neurocysticercosis is associated with epilepsy in pig-raising communities with poor sanitation. Current internationally recognized diagnostic guidelines for neurocysticercosis rely on brain imaging, a technology that is frequently not available or not accessible in areas endemic for neurocysticercosis. Minimally invasive and low-cost aids for diagnosing neurocysticercosis epilepsy could improve treatment of neurocysticercosis. The goal of this study was to test the extent to which patients with neurocysticercosis epilepsy, epilepsy of unknown etiology, idiopathic headaches and among different types of neurocysticercosis lesions could be distinguished from each other based on serum mass profiling. For this, we collected sera from patients with neurocysticercosis-associated epilepsy, epilepsy of unknown etiology, recovered neurocysticercosis, and idiopathic headaches then performed binary group comparisons among them using electrospray ionization mass spectrometry. A leave one [serum sample] out cross validation procedure was employed to analyze spectral data. Sera from neurocysticercosis patients was distinguished from epilepsy of unknown etiology patients with a p-value of 10-28. This distinction was lost when samples were randomized to either group (p-value = 0.22). Similarly, binary comparisons of patients with neurocysticercosis who has different types of lesions showed that different forms of this disease were also distinguishable from one another. These results suggest neurocysticercosis epilepsy can be distinguished from epilepsy of unknown etiology based on biomolecular differences in sera detected by mass profiling.

Identification and Clinical Management of Persons with Chronic Hepatitis C Virus Infection - Cherokee Nation, 2012-2015.

An estimated 3.5 million persons in the United States are living with hepatitis C virus (HCV) infection, resulting in approximately 20,000 deaths each year, primarily from cirrhosis or hepatocellular carcinoma (1,2). American Indian/Alaska Native (AI/AN) populations have the highest incidence of acute HCV infection among all U.S. racial/ethnic groups and are at greater risk for HCV-related mortality compared with the general population (3). In 2013, new antiviral drugs became available that make possible 8-12 week treatment regimens with fewer adverse events and are able to achieve sustained virologic response (SVR) in >90% of treated patients (4), equivalent to a cure of HCV infection. Also of note, HCV testing recommendations were expanded in 2012 by CDC and in 2013 by the U.S. Preventive Services Task Force to include one-time testing of persons born during 1945-1965 (the "baby boomer" cohort) in addition to anyone at increased risk for HCV infection (5,6). Given the availability of new HCV drugs, expanded testing recommendations, and high incidence of HCV infection in AI/AN populations, in October 2012, Cherokee Nation Health Services (CNHS) implemented a tribal HCV testing policy.* As part of the policy, CNHS added a reminder in the electronic health record (EHR) for clinical decision support and provided HCV education to primary care clinicians. From October 2012 to July 2015, among 92,012 persons with at least one CNHS clinic encounter, the cumulative number who received HCV screening for the first time increased from 3,337 (3.6%) to 16,772 (18.2%). The largest percentage of HCV screening was among persons born during 1945-1965. Of 715 persons who tested positive for HCV antibodies, 488 (68.3%) were tested for HCV RNA; among those 488 persons, 388 (79.5%) were RNA positive and were thus confirmed to have chronic HCV infection. Treatment was initiated for 223 (57.5%) of the 388 with chronic infection; 201 (90.1%) completed treatment, of whom 180 (89.6%) achieved SVR. CNHS has successfully increased HCV testing and treatment and is now collaborating with CDC and other external partners to develop an HCV elimination program for the Cherokee Nation that might serve as a model for similar settings.

Microglia and a functional type I IFN pathway are required to counter HSV-1-driven brain lateral ventricle enlargement and encephalitis.

HSV-1 is the leading cause of sporadic viral encephalitis, with mortality rates approaching 30% despite treatment with the antiviral drug of choice, acyclovir. Permanent neurologic deficits are common in patients that survive, but the mechanism leading to this pathology is poorly understood, impeding clinical advancements in treatment to reduce CNS morbidity. Using magnetic resonance imaging and type I IFN receptor-deficient mouse chimeras, we demonstrate HSV-1 gains access to the murine brain stem and subsequently brain ependymal cells, leading to enlargement of the cerebral lateral ventricle and infection of the brain parenchyma. A similar enlargement in the lateral ventricles is found in a subpopulation of herpes simplex encephalitic patients. Associated with encephalitis is an increase in CXCL1 and CXCL10 levels in the cerebral spinal fluid, TNF-α expression in the ependymal region, and the influx of neutrophils of encephalitic mouse brains. Reduction in lateral ventricle enlargement using anti-secretory factor peptide 16 reduces mortality significantly in HSV-1-infected mice without any effect on expression of inflammatory mediators, infiltration of leukocytes, or changes in viral titer. Microglial cells but not infiltrating leukocytes or other resident glial cells or neurons are the principal source of resistance in the CNS during the first 5 d postinfection through a Toll/IL-1R domain-containing adapter inducing IFN-ß-dependent, type I IFN pathway. Our results implicate lateral ventricle enlargement as a major cause of mortality in mice and speculate such an event transpires in a subpopulation of human HSV encephalitic patients.

Non-Small Cell Lung Cancer Presenting as Anterior Nasal Mass and Epistaxis.

Lung malignancy presentation with an uncommon metastatic site is a diagnostic challenge and often associated with poor prognosis. Nasal cavity is a rare metastatic site for any type of lung cancer. We report an unusual case of poorly differentiated adenosquamous carcinoma of the lung with widespread metastasis presenting as a right vestibular nasal mass with epistaxis. A 76-year-old male patient with chronic obstructive pulmonary disease and 80 pack-year smoking history presented with spontaneous epistaxis. He reported a new rapidly growing right-sided nasal vestibular mass first noticed 2 weeks prior. Physical examination showed fleshy mass with crusting in right nasal vestibule along with a left nasal domus mass. Imaging revealed an ovoid mass in the right anterior nostril and a large mass in the right upper lobe of the lung (RULL) along with thoracic vertebral sclerotic metastasis and large left frontal lobe hemorrhagic lesion with severe vasogenic edema. Positron emission tomography scan showed large right upper lobe mass and suspected to be the primary malignancy along with widespread metastasis. Biopsy of the nasal lesion revealed poorly differentiated non-small cell carcinoma with squamous and glandular features. The diagnosis of very poorly differentiated adenosquamous carcinoma of the lung with widespread metastasis was made. In conclusion, unusual metastatic sites with unknown primary lesions require a thorough diagnostic workup involving biopsy and extensive imaging. Lung cancer with unusual metastatic sites is inherently aggressive and associated with poor prognosis. Multidisciplinary treatment modalities should be employed keeping in view the functional status and comorbidities of the patient.

Septic encephalopathy in the elderly - biomarkers of potential clinical utility.

Next to acute sickness behavior, septic encephalopathy is the most frequent involvement of the brain during infection. It is characterized by a cross-talk of pro-inflammatory cells across the blood-brain barrier, by microglial activation and leukocyte migration, but not by the entry of infecting organisms into the brain tissue. Septic encephalopathy is very frequent in older persons because of their limited cognitive reserve. The predominant clinical manifestation is delirium, whereas focal neurological signs and symptoms are absent. Electroencephalography is a very sensitive method to detect functional abnormalities, but these abnormalities are not specific for septic encephalopathy and of limited prognostic value. Routine cerebral imaging by computer tomography usually fails to visualize the subtle abnormalities produced by septic involvement of the brain. Magnetic resonance imaging is by far more sensitive to detect vasogenic edema, diffuse axonal injury or small ischemic lesions. Routine laboratory parameters most suitable to monitor sepsis, but not specific for septic encephalopathy, are C-reactive protein and procalcitonin. The additional measurement of interleukin (IL)-6, IL-8, IL-10 and tumor necrosis factor-α increases the accuracy to predict delirium and an unfavorable outcome. The most promising laboratory parameters to quantify neuronal and axonal injury caused by septic encephalopathy are neurofilament light chains (NfL) and S100B protein. Neuron-specific enolase (NSE) plasma concentrations are strongly influenced by hemolysis. We propose to determine NSE only in non-hemolytic plasma or serum samples for the estimation of outcome in septic encephalopathy.

Correlation between Monocyte Gene Expression and Inflammation on Brain Imaging in Patients with Solitary Cerebral Cysticercus Granuloma.

Prior work has shown that 14 monocyte genes are upregulated in patients with different forms of parenchymal neurocysticercosis, including solitary cysticercus granuloma (SCG). The aim of this study was to investigate whether changes in inflammation associated with SCG seen on follow-up brain imaging are also reflected in changes in expression of these 14 genes. Peripheral blood CD14+ monocytes were isolated from 20 patients with SCG at initial diagnosis and at clinical and imaging follow-up of 6 months or more. Expressions of 14 target monocyte genes were determined by quantitative polymerase chain reaction at each visit. At a median follow-up of 14 months, the SCG had resolved in 11 patients, was persistent in four patients, and had calcified in five patients. Edema seen in the initial imaging in 17 patients had resolved in 15 patients and was markedly reduced in two patients. The expression levels of the monocyte genes LRRFIP2, TAXIBP1, and MZB1 were significantly lower at follow-up, regardless of the status of SCG on follow-up imaging. Our findings show that expression levels of monocyte genes involved with inflammatory processes decrease in patients with SCG concomitant with follow-up imaging that reveals a reduction in inflammation as revealed by complete or near-complete resolution of edema, as well as resolution or reduction in the enhancement of the granuloma.

Progressive cognitive impairment after recovery from neuroinvasive and non-neuroinvasive Listeria monocytogenes infection.

Background: Neuro-cognitive impairment is a deleterious complication of bacterial infections that is difficult to treat or prevent. Listeria monocytogenes (Lm) is a neuroinvasive bacterial pathogen and commonly used model organism for studying immune responses to infection. Antibiotic-treated mice that survive systemic Lm infection have increased numbers of CD8+ and CD4+ T-lymphocytes in the brain that include tissue resident memory (TRM) T cells, but post-infectious cognitive decline has not been demonstrated. We hypothesized that Lm infection would trigger cognitive decline in accord with increased numbers of recruited leukocytes. Methods: Male C57BL/6J mice (age 8 wks) were injected with neuroinvasive Lm 10403s, non-neuroinvasive Δhly mutants, or sterile saline. All mice received antibiotics 2-16d post-injection (p.i.) and underwent cognitive testing 1 month (mo) or 4 mo p.i. using the Noldus PhenoTyper with Cognition Wall, a food reward-based discrimination procedure using automated home cage based observation and monitoring. After cognitive testing, brain leukocytes were quantified by flow cytometry. Results: Changes suggesting cognitive decline were observed 1 mo p.i. in both groups of infected mice compared with uninfected controls, but were more widespread and significantly worse 4 mo p.i. and most notably after Lm 10403s. Impairments were observed in learning, extinction of prior learning and distance moved. Infection with Lm 10403s, but not Δhly Lm, significantly increased numbers of CD8+ and CD4+ T-lymphocytes, including populations expressing CD69 and TRM cells, 1 mo p.i. Numbers of CD8+, CD69+CD8+ T-lymphocytes and CD8+ TRM remained elevated at 4 mo p.i. but numbers of CD4+ cells returned to homeostatic levels. Higher numbers of brain CD8+ T-lymphocytes showed the strongest correlations with reduced cognitive performance. Conclusions: Systemic infection by neuroinvasive as well as non-neuroinvasive Lm triggers a progressive decline in cognitive impairment. Notably, the deficits are more profound after neuroinvasive infection that triggers long-term retention of CD8+ T-lymphocytes in the brain, than after non-neuroinvasive infection, which does not lead to retained cells in the brain. These results support the conclusion that systemic infections, particularly those that lead to brain leukocytosis trigger a progressive decline in cognitive function and implicate CD8+ T-lymphocytes, including CD8+TRM in the etiology of this impairment.

IL-6 increases B-cell IgG production in a feed-forward proinflammatory mechanism to skew hematopoiesis and elevate myeloid production.

Src homology 2 domain-containing inositol 5-phosphatase (SHIP(-/-)) animals display an age-related increase in interleukin-6 (IL-6), a decrease in B lymphopoiesis, and an elevation in myelopoiesis. We investigated the origin of the IL-6 production and show that it is largely produced by peritoneal and splenic macrophages. IL-6 production by these macrophages is not a direct result of the loss of SHIP: IL-6 production is not spontaneous, is absent from bone marrow-derived macrophages, declines with prolonged culture of macrophages, and requires a stimulus present in vivo. The IL-6-rich peritoneal cavity of SHIP(-/-) mice shows more than 700-fold more immunoglobulin G (IgG) than wild-type, approximately 20% of which is aggregated or in an immune complex and contains B220(+) cells that secrete IgG. The SHIP-deficient peritoneal macrophages show evidence of IgG receptor stimulation. Animals lacking both the signal-transducing gamma-chain of IgG receptors and SHIP or Ig and SHIP produce less IL-6. The data indicate a feed-forward process in which peripheral macrophages, responding through IgG receptors to secreted IgG, produce IL-6, to support further B-cell production of IgG. Because of the proinflammatory phenotype of SHIP(-/-) animals, these findings emphasize the importance of IL-6-neutralizing strategies in autoimmune and proinflammatory diseases.

Severe Listeria monocytogenes infection induces development of monocytes with distinct phenotypic and functional features.

Monocytes perform diverse roles during infection with the facultative intracellular bacterium Listeria monocytogenes. They are essential as bactericidal cells in host defense but can also become Trojan horses transporting bacteria into the brain. To explain these contrasting roles, we characterized bone marrow (BM) monocytes in steady state and generated during lethal and sublethal L. monocytogenes infection. Ly-6C(high)CD11b(+) BM monocytes expressed high amounts of M-CSFR/CD115 in steady state and 72 h following sublethal infection. However, infection with increasing numbers of bacteria resulted in progressive loss of CD115 and strongly decreased CD115-encoding c-fms mRNA expression. Conversely, analysis of regulatory molecules showed de novo expression of the nonsignaling IL-1RII, CD121b, under the same conditions. Ly-6C(high)CD11b(+) monocytes in circulation also acquired a CD115(neg/low)CD121b(high) phenotype during lethal infection. These BM monocytes showed upregulation of suppressor of cytokine signaling 1 and 3 and IL-1R-"associated kinase-M to a greater extent and/or earlier compared with cells from sublethal infection and showed decreased LPS-induced IL-6 production despite similar levels of surface TLR4 expression. BM monocytes from uninfected or sublethally infected mice bound and internalized very few L. monocytogenes in vitro. However, both functions were significantly increased in monocytes developing during lethal infection. Nonetheless, these cells did not produce reactive oxygen intermediates, suggesting an inability to kill L. monocytogenes. Together, these data show that systemic infections with lethal and sublethal amounts of bacteria differentially shape developing BM monocytes. This results in distinct phenotypic and functional properties consistent with being Trojan horses rather than bactericidal effector cells.

Discriminating experimental Listeria monocytogenes infections in mice using serum profiling.

Serum profiling was used to distinguish mice infected with wild-type or mutant Listeria monocytogenes from noninfected control mice. Identifications of significant electrospray ionization mass spectrometry (ESI-MS) sera peak areas between Listeria-infected- and control mice were performed using t tests. ESI-MS cohort peak distributions differed from mice infected with wild-type or ∆actA Listeria versus control mice with p values of 0.00012 and 0.015, respectively. A "% wild-type Listeria peaks identified" assessment tool yielded values of 64 % for wild-type infection, 51 % for ∆actA infection, and 47 % for no infection. Receiver operator characteristic area discriminatory values were 0.97 (wild-type) and 0.82 (∆actA) versus controls. Predictive value measurements revealed overall test sensitivities of 88 % for wild-type infection and 63 % for ∆actA infection. These studies indicate that ESI-MS serum profiling holds promise for diagnosis of infection with intracellular pathogens such as Listeria and indicate that the technology could be useful in understanding the L. monocytogenes infection process.

Listeria monocytogenes strains selected on ciprofloxacin or the disinfectant benzalkonium chloride exhibit reduced susceptibility to ciprofloxacin, gentamicin, benzalkonium chloride, and other toxic compounds.

Listeria monocytogenes is a leading agent for severe food-borne illness and death in the United States and other nations. Even though drug resistance has not yet threatened therapeutic interventions for listeriosis, selective pressure associated with exposure to antibiotics and disinfectants may result in reduced susceptibility to these agents. In this study, selection of several L. monocytogenes strains on either ciprofloxacin (2 µg/ml) or the quaternary ammonium disinfectant benzalkonium chloride (BC; 10 µg/ml) led to derivatives with increased MICs not only to these agents but also to several other toxic compounds, including gentamicin, the dye ethidium bromide, and the chemotherapeutic drug tetraphenylphosphonium chloride. The spectrum of compounds to which these derivatives exhibited reduced susceptibility was the same regardless of whether they were selected on ciprofloxacin or on BC. Inclusion of strains harboring the large plasmid pLM80 revealed that MICs to ciprofloxacin and gentamicin did not differ between the parental and plasmid-cured strains. However, ciprofloxacin-selected derivatives of pLM80-harboring strains had higher MICs than those derived from the plasmid-cured strains. Susceptibility to the antimicrobials was partially restored in the presence of the potent efflux inhibitor reserpine. Taken together, these data suggest that mutations in efflux systems are responsible for the multidrug resistance phenotype of strains selected on ciprofloxacin or BC.

Synthetic human chorionic gonadotropin-related oligopeptides impair early innate immune responses to Listeria monocytogenes in Mice.

Background. Synthetic human chorionic gonadotropin (hCG)-related oligopeptides are potent inhibitors of pathogenic inflammatory responses induced by in vivo lipopolysaccharide exposure or hemorrhagic shock-induced injury. In this study, we tested whether hCG-related oligopeptide treatment similarly altered inflammatory responses and innate host defenses in mice during experimental Listeria monocytogenes infection. Methods. Mice were infected with L. monocytogenes and treated with hCG-related oligopeptides (LQGV, VLPALP, or AQGV) or phosphate-buffered saline. Subsequently, mice were analyzed for bacterial loads, cytokine and chemokine responses, and inflammatory cell infiltrates in target organs. Results. Oligopeptide administration increased bacterial numbers in the spleen and liver at 6 h after infection. Simultaneously, CXCL1/KC and CCL2/MCP-1 plasma levels as well as neutrophil numbers in the spleen, blood, and peritoneal cavity decreased. In contrast, at 18 h after infection, systemic tumor necrosis factor alpha, interleukin 12 p70, interleukin 6, and interferon gamma levels increased statistically significantly in oligopeptide-treated mice compared with controls, which correlated with increased bacterial numbers. Conclusion. These data show that treatment with hCG-related oligopeptides (LQGV, VLPALP, and AQGV) inhibits early innate immune activation by reducing initial chemokine secretion following infection. This leads to bacterial overgrowth with subsequent enhanced systemic inflammation. Our data underscore the importance of early innate immune activation and suggest a role for hCG-derived oligopeptides at the placenta that increases the risk of L. monocytogenes infections.

Endothelial Dysfunction and Impaired Neurovascular Coupling Responses Precede Cognitive Impairment in a Mouse Model of Geriatric Sepsis.

Sepsis is a life-threatening condition, the incidence of which is significantly increased in elderly patients. One of the long-lasting effects of sepsis is cognitive impairment defined as a new deficit or exacerbation of preexisting deficits in global cognition or executive function. Normal brain function is dependent on moment-to-moment adjustment of cerebral blood flow to match the increased demands of active brain regions. This homeostatic mechanism, termed neurovascular coupling (NVC, also known as functional hyperemia), is critically dependent on the production of vasodilator NO by microvascular endothelial cells in response to mediators released from activated astrocytes. The goal of this study was to test the hypothesis that sepsis in aging leads to impairment of NVC responses early after treatment and that this neurovascular dysfunction associates with impairments in cognitive performance and vascular endothelial dysfunction. To test this hypothesis, we used a commonly studied bacterial pathogen, Listeria monocytogenes, to induce sepsis in experimental animals (males, 24 months of age) and subjected experimental animals to a standard clinical protocol of 3 doses of ampicillin i.p. and 14 days of amoxicillin added to the drinking water. NVC responses, endothelial function and cognitive performance were measured in septic and age-matched control groups within 14 days after the final antibiotic treatment. Our data demonstrate that sepsis in aging significantly impairs NVC responses measured in somatosensory cortex during whisker stimulation, significantly impairs endothelial function in isolated and pressure cannulated aorta rings in response to acetylcholine stimulation. No significant impairment of cognitive function in post-sepsis aged animals has been observed when measured using the PhenoTyper homecage based system. Our findings suggest that sepsis-associated endothelial dysfunction and impairment of NVC responses may contribute to long-term cognitive deficits in older sepsis survivors.