Abrogation of efflux pump activity, biofilm formation, and immune escape by candidacidal geraniol in emerging superbug, Candida auris / Anulación de la actividad de la bomba de eflujo, formación de biopelículas y escape inmunológico por el geraniol candidacida en la superbacteria emergente Candida auris

During the last decade, Candida auris emerged as a threatening human fungal pathogen that notably caused outbreaks around the globe with high mortality. Considering C. auris species as newly discovered fungi, the evolutionary features remain elusive. The antifungal resistance which is a norm in C. auris underlines the need for innovative therapeutic options. ATP Binding Cassette (ABC) superfamily efflux pumps overexpression and biofilms are known to be major contributors to multidrug resistance (MDR) in C. auris. Therefore, herein, we investigated the antifungal potential of geraniol (Ger) as a promising natural compound in the fight against MDR C. auris. Our experiments proved that Ger was fungicidal in nature and impaired rhodamine 6G (R6G) efflux, confirming the specific effect on ABC transporters. Kinetic studies unravelled the competitive mode of inhibition by Ger for R6G efflux since the apparent Km increased with no change in Vmax value. Mechanistic insights also revealed that Ger depleted ergosterol content in C. auris. Furthermore, Ger led to inhibition in biofilm formation as evident from crystal violet staining, biofilm metabolic and biomass measurements. Additionally, enhanced survival of Caenorhabditis elegans model after C. auris infection demonstrated the in vivo efficacy of Ger. Lastly, the in vivo efficacy was confirmed from a THP-1 cell line model which depicted enhanced macrophage–mediated killing in the presence of Ger. Modulation of C. auris efflux pump activity and biofilm formation by Ger represents a promising approach to combat MDR. Together, this study demonstrated the potential therapeutic insights of Ger as a promising addition to the antifungal armamentarium required to treat emerging and resistant C. auris.(AU)

Etiology of Acute Infectious Meningitis and Meningoencephalitis in Karachi, Pakistan: Retrospective Observational Study from a Tertiary Care Center.

Meningoencephalitis (ME) is potentially fatal and is caused by a wide array of pathogens. Diagnostic and health-care access gaps prevent accurate estimation of the pathogen-specific burden in low-resource settings. We present pathogen-specific etiologies among patients hospitalized with ME in Karachi, Pakistan. We performed a retrospective hospital database evaluation of pathogen etiology and outcomes of community-acquired infectious ME at a single tertiary care center in Karachi, Pakistan. Annual rates of hospitalization (ARH) were calculated by adjusting for missed cases and are reported per 100,000 population. From May 2017 to April 2020, 522 episodes of infectious ME were identified in 514 patients. The overall ARH from ME was 5.7/100,000 population (95% CI, 5.1-6.1). Among children younger than 5 years, the ARH was 9.8/100,000 population (95% CI, 8.1-11.8). Unknown causes of ME resulted in the greatest burden, with an ARH of 1.9/100,000 population (95% CI, 1.7-2.2). Among known causes, the greatest burden of hospitalizations resulted from tuberculous ME (0.8/100,000; 95% CI, 0.6-0.97), followed by pneumococcal and enteroviral ME (both 0.6/100,000 population; 95% CI, 0.5-0.8). The burden of ME caused by pathogens preventable through vaccination or public health measures outweighed that of ME from other causes (P = 0.0092, Fisher's exact test). We report a broad range of pathogens causing ME in southern Pakistan and show a high burden of preventable illness. Synergistic actions to improve diagnostic strategies, increase vaccinations, and introduce measures to reduce water-borne and vector-borne diseases are required to reduce the ME burden in Pakistan and prevent future outbreaks.

Abrogation of efflux pump activity, biofilm formation, and immune escape by candidacidal geraniol in emerging superbug, Candida auris.

During the last decade, Candida auris emerged as a threatening human fungal pathogen that notably caused outbreaks around the globe with high mortality. Considering C. auris species as newly discovered fungi, the evolutionary features remain elusive. The antifungal resistance which is a norm in C. auris underlines the need for innovative therapeutic options. ATP Binding Cassette (ABC) superfamily efflux pumps overexpression and biofilms are known to be major contributors to multidrug resistance (MDR) in C. auris. Therefore, herein, we investigated the antifungal potential of geraniol (Ger) as a promising natural compound in the fight against MDR C. auris. Our experiments proved that Ger was fungicidal in nature and impaired rhodamine 6G (R6G) efflux, confirming the specific effect on ABC transporters. Kinetic studies unravelled the competitive mode of inhibition by Ger for R6G efflux since the apparent Km increased with no change in Vmax value. Mechanistic insights also revealed that Ger depleted ergosterol content in C. auris. Furthermore, Ger led to inhibition in biofilm formation as evident from crystal violet staining, biofilm metabolic and biomass measurements. Additionally, enhanced survival of Caenorhabditis elegans model after C. auris infection demonstrated the in vivo efficacy of Ger. Lastly, the in vivo efficacy was confirmed from a THP-1 cell line model which depicted enhanced macrophage-mediated killing in the presence of Ger. Modulation of C. auris efflux pump activity and biofilm formation by Ger represents a promising approach to combat MDR. Together, this study demonstrated the potential therapeutic insights of Ger as a promising addition to the antifungal armamentarium required to treat emerging and resistant C. auris.

Female genital tuberculosis in Pakistan - A retrospective review of 10-year laboratory data and analysis of 32 cases.

Background: Female genital tuberculosis (FGTB) is an underobserved clinical entity owing to diagnostic challenges stemming from difficulty of obtaining diagnostic specimens and paucibacillary nature of the disease. Yet, FGTB is a cause of infertility, pelvic pain, or menstrual irregularities in high-burden countries. To assess laboratory and microbiology diagnostic utilization for FGTB in Pakistan, we have collected data from 2007 to 2016 to inform the need for improved laboratory diagnostics. The objectives of this study were to determine the proportion of FGTB as culture-confirmed extrapulmonary tuberculosis (EPTB) and to describe the characteristics of women with culture-confirmed FGTB in a nationwide laboratory network in Pakistan. Method: A retrospective database was established by accessing laboratory archives and analyzed by sex and source to determine extrapulmonary cases among women. Data were checked for quality, and after removing patient identifiers and duplicate samples, frequencies were calculated in MS Excel. Clinical characteristics of patients were derived from a linked hospital database for those patients who were diagnosed and managed at the affiliated university hospital in Karachi, Pakistan. Results: Over 10 years, 410,748 mycobacterial cultures were received from multiple geographic sites throughout Pakistan and processed at the study laboratory. The overall mean culture positivity rate was 5.9% ± 3.5%, while the mean culture positivity rate among females was 2.8% ± 0.8%. Among female culture-confirmed tuberculosis cases, the pulmonary-to-EPTB ratio of infection was 5. Over 10 years, a total of 32 FGTB cases were reported on the basis of positive cultures for Mycobacterium tuberculosis; 3 (9.4%) were rifampin resistant. Conclusions: FGTB currently constitutes a small but significant proportion of culture-confirmed EPTB. A fewer number of laboratory requisitions suggest the need to increase awareness and testing. The advent of high-sensitivity molecular testing on extrapulmonary specimens has the potential to improve diagnostic accuracy and improved detection of FGTB cases in high-burden regions.

Eggerthella lenta bacteraemia in endometrial adenocarcinoma - a case report from Pakistan.

We report a case of Eggerthella lenta bacteraemia. An elderly lady with metastasised endometrial adenocarcinoma presented with complaints of fever nausea vomiting and abdominal pain. CT scan of the abdomen showed enlarged liver with multiple metastatic lesions raising suspicion of small-bowel obstruction. Due to multiple comorbid conditions, surgery was contraindicated and she was treated empirically with meropenem and vancomycin. Blood culture received on admission grew Eggerthela lenta.

Investigation of Japanese encephalitis virus as a cause of acute encephalitis in southern Pakistan, April 2015-January 2018.

BACKGROUND: Japanese encephalitis (JE) occurs in fewer than 1% of JE virus (JEV) infections, often with catastrophic sequelae including death and neuropsychiatric disability. JEV transmission in Pakistan was documented in 1980s and 1990s, but recent evidence is lacking. Our objective was to investigate JEV as a cause of acute encephalitis in Pakistan. METHODS: Persons aged ≥1 month with possible JE admitted to two acute care hospitals in Karachi, Pakistan from April 2015 to January 2018 were enrolled. Cerebrospinal fluid (CSF) or serum samples were tested for JEV immunoglobulin M (IgM) using the InBios JE DetectTM assay. Positive or equivocal samples had confirmatory testing using plaque reduction neutralization tests. RESULTS: Among 227 patients, testing was performed on CSF in 174 (77%) and on serum in 53 (23%) patients. Six of eight patient samples positive or equivocal for JEV IgM had sufficient volume for confirmatory testing. One patient had evidence of recent West Nile virus (WNV) neurologic infection based on CSF testing. One patient each had recent dengue virus (DENV) infection and WNV infection based on serum results. Recent flavivirus infections were identified in two persons, one each based on CSF and serum results. Specific flaviviruses could not be identified due to serologic cross-reactivity. For the sixth person, JEV neutralizing antibodies were confirmed in CSF but there was insufficient volume for further testing. CONCLUSIONS: Hospital-based JE surveillance in Karachi, Pakistan could not confirm or exclude local JEV transmission. Nonetheless, Pakistan remains at risk for JE due to presence of the mosquito vector, amplifying hosts, and rice irrigation. Laboratory surveillance for JE should continue among persons with acute encephalitis. However, in view of serological cross-reactivity, confirmatory testing of JE IgM positive samples at a reference laboratory is essential.

High-throughput purification platform in support of drug discovery.

The application of parallel synthesis is an efficient approach to explore the chemical space and to rapidly develop meaningful structure activity relationship (SAR) data for drug discovery programs. However, the effectiveness of the parallel synthesis requires a high throughput purification workflow that can process a large number of crude samples within a meaningful time frame. This paper describes a high throughput purification platform that has been adopted at Merck's Rahway research site. The platform includes the evaluation of crude samples, mass-directed HPLC purification, fraction analysis, compound registration, final compound purity assessment and assay distribution. Assisting with the sample tracking and the data management is the internally designed laboratory information management system, Light Automation Framework (LAF). Using this process and the tools described herein, the group has successfully achieved purities of 95% or greater for 90% of samples.

Depletion of forestry resource biomass due to industrialization pressure: a ratio-dependent mathematical model.

A model for interactions between forestry biomass, wildlife population and industrialization pressure is proposed and analysed. Here, the functional responses are assumed to be ratio-dependent type. The effect of forestry biomass depletion in a forested habitat caused by industrialization pressure on the survival of the forestry biomass dependent wildlife species is studied. The behaviours of the system near all ecological feasible equilibria are analysed.

Development and validation of an indirect competitive enzyme linked-immunosorbent assay for the determination of potentially allergenic sesame (Sesamum indicum) in food.

This study was designed to develop an indirect competitive enzyme linked-immunosorbent assay (ELISA) to detect traces of sesame in food. Antibodies against sesame were prepared by immunizing a hen with a protein extract of white, peeled sesame. The ELISA did not show any cross-reactivity with 12 of 13 food ingredients tested, only for chocolate was a low cross-reactivity of 0.7% observed. To eliminate matrix effects, sesame protein standard solutions were prepared by diluting the sesame extract with blank food matrix (1:20 diluted with PBS). Recovery of sesame protein in food samples (crisp toasts, snacks, and rolls) spiked with different sesame protein concentrations ranged from 85% to 120%, with the exception of multigrain crisp toast, resulting in too high recoveries (117%-160%) and whole grain bread, yielding too low recoveries (70%-85%). In crisp bread, cracker, cereals, and snacks the limit of detection (LOD) was found to be 5 microg of sesame protein/g of food, in fresh breads and rolls, the LOD was 11 microg of sesame protein/g of food.

Patient-controlled analgesia with fentanyl for burn dressing changes.

In this randomized, double-blinded study in 60 ASA I or II adults with >20% body-surface area thermal burns, we investigated the feasibility of patient-controlled analgesia (PCA) with fentanyl for pain management during dressing changes and determined the optimal PCA-fentanyl demand dose. An initial loading dose of IV fentanyl 1 microg/kg was administered. Patients received on-demand analgesia with fentanyl (10, 20, 30, and 40 microg) whenever their visual analog scale (VAS) score was >2. Mean VAS scores in the 10 and 20 microg groups (7.73 +/- 1.33 and 7.20 +/- 1.21, respectively) were significantly higher than those in the 30 and 40 microg groups (4.47 +/- 0.83 and 3.90 +/- 0.63, respectively) (all P = 0.000). Demand/delivery ratios were significantly larger in the 10 and 20 microg groups (3.03 +/- 1.06 and 2.54 +/- 0.49, respectively) than those in the 30 and 40 microg groups (1.36 +/- 0.34 and 1.37 +/- 0.36, respectively) (all P = 0.000). VAS scores and demand/delivery ratios were comparable in the 30 and 40 microg groups (P = 0.260 and P = 0.977, respectively), which suggests comparable analgesic efficacy. There was no hemodynamic instability or respiratory depression. The optimal demand dose of PCA-fentanyl was 30 microg (5-min lockout interval) after an initial loading dose of IV fentanyl 1 microg/kg.