Undetectable JC virus CSF PCR in patients with JC virus-induced progressive multifocal leukoencephalopathy.

The diagnosis of progressive multifocal leukoencephalopathy (PML) is based on a combination of clinical, radiographic, and laboratory findings. However, negative JC polyomavirus (JCPyV) PCR in CSF does not always rule out JCPyV-related PML. In this narrative review, we sought to examine the characteristic of biopsy-proven PML in patients with undetectable JCPyV CSF PCR and provide alternative approaches in this scenario.

Carbapenem-resistant Lactobacillus intra-abdominal infection in a renal transplant recipient with a history of probiotic consumption.

BACKGROUND: Lactobacillus sp. is a low virulence bacterium, which rarely causes infection in immunocompetent individuals and usually is considered a contaminant. Normally this organism is susceptible to ß-lactam antibiotics, yet resistant strains have been reported. CASE PRESENTATION AND DISCUSSION: Here, we report a case of a 60-year-old renal transplant recipient who developed an intra-abdominal abscess which grew a carbapenem-resistant Lactobacillus casei. This is significant since it is the first report of a clinical isolate of Lactobacillus sp. that demonstrated both microbiological and clinical resistance to carbapenem use. Moreover, the probiotic supplement that the patient had taken also grew a similar organism raising the concern of probiotic associated infection in immunocompromised individual.

A conserved PHD finger protein and endogenous RNAi modulate insulin signaling in Caenorhabditis elegans.

Insulin signaling has a profound effect on longevity and the oxidative stress resistance of animals. Inhibition of insulin signaling results in the activation of DAF-16/FOXO and SKN-1/Nrf transcription factors and increased animal fitness. By studying the biological functions of the endogenous RNA interference factor RDE-4 and conserved PHD zinc finger protein ZFP-1 (AF10), which regulate overlapping sets of genes in Caenorhabditis elegans, we identified an important role for these factors in the negative modulation of transcription of the insulin/PI3 signaling-dependent kinase PDK-1. Consistently, increased expression of pdk-1 in zfp-1 and rde-4 mutants contributed to their reduced lifespan and sensitivity to oxidative stress and pathogens due to the reduction in the expression of DAF-16 and SKN-1 targets. We found that the function of ZFP-1 in modulating pdk-1 transcription was important for the extended lifespan of the age-1(hx546) reduction-of-function PI3 kinase mutant, since the lifespan of the age-1; zfp-1 double mutant strain was significantly shorter compared to age-1(hx546). We further demonstrate that overexpression of ZFP-1 caused an increased resistance to oxidative stress in a DAF-16-dependent manner. Our findings suggest that epigenetic regulation of key upstream signaling components in signal transduction pathways through chromatin and RNAi may have a large impact on the outcome of signaling and expression of numerous downstream genes.

Morphoproteomic Features of Pulmonary Influenza A (H1N1) with Therapeutic Implications: A Case Study.

OBJECTIVE: Influenza pandemic of the human lung was caused by the Influenza A (H1N1) over 100 years ago in 1918, but it recurred in pandemic fashion in 2009. Understanding the pathobiology of this infectious agent in the human lung could lead to adjuvant therapies that are relatively non-toxic and reduce the mortality of the human host. Overall, our objective was to apply morphoproteomics to pulmonary lung sections from an autopsied victim so that we may better define its biology from the perspective of its interaction with the host and provide options for therapeutic targets. METHODS: Morphoproteomic analysis from a case study of this Influenza A (H1N1) pulmonary infection included immunohistochemical probes to detect the expressions of fatty acid synthase (FAS), CD163+ (M2 polarized monocytes/macrophages), and programmed death-ligand 1 (PD-L1) expression as part of the host response to interaction with the Influenza A (H1N1) virus. RESULTS: Representative sections of the Influenza A (H1N1) victim's lung showed: cytoplasmic expression of FAS in most of the sloughed and atypical alveolar pneumocytes; abundance of intra-alveolar and alveolar interstitial CD163+ macrophages/monocytes; and PD-L1 expression on occasional macrophages, and focally on collections of alveolar pneumocytes and the alveolar interstitium. CONCLUSION: Morphoproteomics and microanatomical features coincide with the etiopathogenic features of pulmonary Influenza A (H1N1) infection and the host response. This plus data mining of the medical literature suggests that adjunctive, targeted therapy such as metformin and vitamin D3 could address the biology of Influenza A (H1N1) pneumonia, enhance the host immune response, and prevent its progression to a life-threatening, ventilator-dependent clinical situation.

Successful implementation of the CDC recommendations during the care of 2 patients with Candida auris in in-patient rehabilitation and intensive care settings.

Candida auris presents a unique challenge to practitioners and infection control teams worldwide because of its virulence, alarming resistance profile, environmental fitness, and risk of nosocomial transmission. We describe 2 cases of Candida auris infection managed with the CDC recommendations with no evidence of in-hospital transmission.

The molecular alarmone (p)ppGpp mediates stress responses, vancomycin tolerance, and virulence in Enterococcus faecalis.

The stringent response is a global bacterial response to stress that is mediated by accumulation of the alarmone (p)ppGpp. In this study, treatment with mupirocin was shown to induce high levels of (p)ppGpp production in Enterococcus faecalis, indicating that this nosocomial pathogen can mount a classic stringent response. In addition, (p)ppGpp was found to accumulate in cells subjected to heat shock, alkaline shock, and inhibitory concentrations of vancomycin. Sequence analysis of the E. faecalis genome indicated that (p)ppGpp synthesis is catalyzed by the bifunctional synthetase/hydrolase RelA and the RelQ small synthase. The (p)ppGpp profiles of DeltarelA, DeltarelQ, and DeltarelAQ strains revealed that RelA is the major enzyme responsible for the accumulation of (p)ppGpp during antibiotic or physical stresses, while RelQ appears to be responsible for maintaining basal levels of alarmone during homeostatic growth. Compared to its parent, the DeltarelA strain was more susceptible to several stress conditions, whereas complete elimination of (p)ppGpp in a DeltarelAQ double mutant restored many of the stress-sensitive phenotypes of DeltarelA. Interestingly, growth curves and time-kill studies indicated that tolerance to vancomycin is enhanced in the DeltarelA strain but diminished in the DeltarelQ and DeltarelAQ strains. Finally, virulence of the DeltarelAQ strain but not of the DeltarelA or DeltarelQ strain was significantly attenuated in the Caenorhabditis elegans model. Taken together, these results indicate that (p)ppGpp pools modulate environmental stress responses, vancomycin tolerance, and virulence in this important nosocomial pathogen.

Ce-Duox1/BLI-3 generates reactive oxygen species as a protective innate immune mechanism in Caenorhabditis elegans.

Caenorhabditis elegans was recently developed as a model system to study both pathogen virulence mechanisms and host defense responses. We previously demonstrated that C. elegans produces reactive oxygen species (ROS) in response to exposure to the important gram-positive nosocomial pathogen Enterococcus faecalis. We also presented evidence of oxidative stress and upregulation of stress responses after exposure to the pathogen. As in mammalian systems, this new work shows that production of ROS for innate immune functions occurs via an NADPH oxidase. Specifically, reducing expression of a dual oxidase, Ce-Duox1/BLI-3, causes a decrease in ROS production in response to E. faecalis. We also present evidence that reduction of expression of Ce-Duox1/BLI-3 increases susceptibility to this pathogen, specifically when expression is reduced in the intestine and the hypodermis. Ce-Duox1/BLI-3 was previously characterized as having a role in cuticle cross-linking. Two C. elegans mutants with point mutations in the peroxidase domain that exhibit severe cuticle defects were discovered to be unaffected in ROS production or pathogen susceptibility. These results demonstrate an important biological role for the peroxidase domain in cuticle cross-linking that is unrelated to ROS production. To further demonstrate the protective effects of the pathogen-induced ROS production, we show that antioxidants that scavenge ROS increase the sensitivity of the nematode to the infection, in stark contrast to their longevity-promoting effects under nonpathogenic conditions. In conclusion, we postulate that the generation of ROS by NADPH oxidases in the barrier epithelium is an ancient, highly conserved innate immune defense mechanism.

Seroprevalence of Strongyloides stercoralis and Evaluation of Universal Screening in Kidney Transplant Candidates: A Single-Center Experience in Houston (2012-2017).

BACKGROUND: Disseminated strongyloidiasis in solid organ transplant recipients is a rare but devastating infection. In our center, we implemented a universal screening of all candidates for kidney transplantation. We assessed the seroprevalence and utility of universal screening for strongyloidiasis in our center. METHODS: Patients were identified from our transplant referral list (from July 2012 to June 2017). Demographics, pretransplant laboratory, and serological screenings were retrospectively collected. For Strongyloides-seropositive (SSp) patients, data on travel history, symptoms, treatment, and stool ova and parasite examinations were extracted. Logistic regression and multiple imputation for missing data were performed. RESULTS: A total of 1689 patients underwent serological screening, of whom 168 (9.9%) were SSp. Univariate analysis revealed that SSp patients had higher rates of eosinophilia, diabetes mellitus, latent tuberculosis and were likely to be either Hispanic or Asian (P < .05). In multivariate analysis, eosinophilia (P = .01), diabetes mellitus (P = .02), and Asian race (P = .03) were associated with being SSp, but 45 (27%) of the SSp patients did not have any of these 3 factors, and 18 SSp patients (11%) had no epidemiological risk factors. All patients received ivermectin, and none developed disseminated strongyloidiasis. Of patients who underwent serological screening on multiple occasions, 6.8% seroconverted while waiting for kidney transplantation. CONCLUSIONS: We found a high rate of Strongyloides seropositivity among our kidney transplantation candidates. No epidemiological risk factors effectively predicted SSp status in our population, and universal screening identified a large number of patients without such factors. Serial screening should be considered when a long wait time is expected before transplantation.

Oxidative stress enzymes are required for DAF-16-mediated immunity due to generation of reactive oxygen species by Caenorhabditis elegans.

Caenorhabditis elegans has recently been developed as a model for microbial pathogenesis, yet little is known about its immunological defenses. Previous work implicated insulin signaling in mediating pathogen resistance in a manner dependent on the transcriptional regulator DAF-16, but the mechanism has not been elucidated. We present evidence that C. elegans, like mammalian phagocytes, produces reactive oxygen species (ROS) in response to pathogens. Signs of oxidative stress occur in the intestine - the site of the host-pathogen interface - suggesting that ROS release is localized to this tissue. Evidence includes the accumulation of lipofuscin, a pigment resulting from oxidative damage, at this site. In addition, SOD-3, a superoxide dismutase regulated by DAF-16, is induced in intestinal tissue after exposure to pathogenic bacteria. Moreover, we show that the oxidative stress response genes sod-3 and ctl-2 are required for DAF-16-mediated resistance to Enterococcus faecalis using a C. elegans killing assay. We propose a model whereby C. elegans responds to pathogens by producing ROS in the intestine while simultaneously inducing a DAF-16-dependent oxidative stress response to protect adjacent tissues. Because insulin-signaling mutants overproduce oxidative stress response enzymes, the model provides an explanation for their increased resistance to pathogens.

Case report: Mycobacterium bovis orchitis post intravesical Bacillus Calmette Guerin.

Bacillus Calmette-Guérin (BCG) therapy is a common adjunctive therapy for superficial bladder carcinoma but there has been noted to be complications from this treatment ranging from general disseminated infections to osteomuscular involvement. We report a case regarding a 63 year old gentleman who presented with right testicular swelling and pain and later found to have evidence consistent with Mycobacterium bovis orchitis. We also detail a literature review regarding genitourinary infections secondary to BCG therapy and discussion regarding current testing modalities.

Dirofilariasis Presenting as an Infiltrative Mass in the Right Buccal Space.

Dirofilariasis is caused by filarial nematodes (roundworms) of the genus Dirofilaria Dirofilariasis of the oral mucosa is very rare. Herein, we report a case of a 79-year-old man who had a slowly growing infiltrative mass in the right buccal space. Histopathologic examination showed an inflammatory infiltrate with eosinophilia, histiocytes, and small organisms (0.2-0.3 mm). Digital images were sent to the Centers for Disease Control and Prevention, which identified the parasite as a nematode in the genus Dirofilaria It appeared to be dead and degenerating, but external, fine longitudinal cuticular ridges and the presence of tall muscle cells were diagnostic. Thus, Dirofilaria, despite its rarity, should be considered in the differential diagnosis of tumor-like lesions in the buccal mucosa.

Localization of the Dual Oxidase BLI-3 and Characterization of Its NADPH Oxidase Domain during Infection of Caenorhabditis elegans.

Dual oxidases (DUOX) are enzymes that contain an NADPH oxidase domain that produces hydrogen peroxide (H2O2) and a peroxidase domain that can utilize H2O2 to carry out a variety of reactions. The model organism Caenorhabditis elegans produces the DUOX, BLI-3, which has roles in both cuticle development and in protection against infection. In previous work, we demonstrated that while certain peroxidases were protective against the human bacterial pathogen Enterococcus faecalis, the peroxidase domain of BLI-3 was not, leading to the postulate that the NADPH oxidase domain is the basis for BLI-3's protective effects. In this work, we show that a strain carrying a mutation in the NADPH oxidase domain of BLI-3, bli-3(im10), is more susceptible to E. faecalis and the human fungal pathogen Candida albicans. Additionally, less H2O2 is produced in response to pathogen using both an established Amplex Red assay and a strain of C. albicans, WT-OXYellow, which acts as a biosensor of reactive oxygen species (ROS). Finally, a C. elegans line containing a BLI-3::mCherry transgene was generated. Previous work suggested that BLI-3 is produced in the hypodermis and the intestine. Expression of the transgene was observed in both these tissues, and additionally in the pharynx. The amount and pattern of localization of BLI-3 did not change in response to pathogen exposure.

Quinones as antimycobacterial agents.

Mycobacterium tuberculosis is a serious worldwide health threat, killing almost 3 million people per year. Other mycobacterial species, especially Mycobacterium avium, are emerging pathogens in the immunocompromised population, most notably AIDS patients. These nontuberculous mycobacteria (NTM) are ubiquitous in the environment, and naturally resistant to many disinfection procedures. Treatment options are limited, and no new antibiotics have been developed against mycobacteria since the 1970s. There is a desperate need for new biocides and antibiotics to prevent and treat mycobacterial infections. A small aromatic compound library has been screened for effectiveness in growth inhibition or killing of mycobacteria. Four species, representing the M. tuberculosis complex, the slow-growing NTM, and the rapid-growing NTM were used. Active compounds had minimal inhibitory concentrations as low as 12.5 microg/mL, with the active component being a quinone. The primarily bactericidal activity observed represents a unique mechanism of action. A fluorescent assay involving M. smegmatis expressing gfp was analyzed as a rapid assay for predicting inhibitory activity, but failed to predict activity well. Our compounds may have significant utility as soluble biocides against mycobacteria and other hardy nosocomial pathogens.