Assessment of the Novel Anti-Seizure Potential of Validamycin A Using Zebrafish Epilepsy Model.

Epilepsy is a prevalent neurological disorder characterized by recurrent seizures. Validamycin A (VA) is an antibiotic fungicide that inhibits trehalase activity and is widely used for crop protection in agriculture. In this study, we identified a novel function of VA as a potential anti-seizure medication in a zebrafish epilepsy model. Electroencephalogram (EEG) analysis demonstrated that VA reduced pentylenetetrazol (PTZ)-induced seizures in the brains of larval and adult zebrafish. Moreover, VA reduced PTZ-induced irregular movement in a behavioral assessment of adult zebrafish. The developmental toxicity test showed no observable anatomical alteration when the zebrafish larvae were treated with VA up to 10 µM within the effective range. The median lethal dose of VA in adult zebrafish was > 14,000 mg/kg. These results imply that VA does not demonstrate observable toxicity in zebrafish at concentrations effective for generating anti-seizure activity in the EEG and alleviating abnormal behavior in the PTZ-induced epileptic model. Furthermore, the effectiveness of VA was comparable to that of valproic acid. These results indicate that VA may have a potentially safer anti-seizure profile than valproic acid, thus offering promising prospects for its application in agriculture and medicine.

Ipconazole Disrupts Mitochondrial Homeostasis and Alters GABAergic Neuronal Development in Zebrafish.

Ipconazole, a demethylation inhibitor of fungal ergosterol biosynthesis, is widely used in modern agriculture for foliar and seed treatment, and is authorized for use in livestock feed. Waste from ipconazole treatment enters rivers and groundwater through disposal and rain, posing potential toxicity to humans and other organisms. Its metabolites remain stable under standard hydrolysis conditions; however, their neurodevelopmental toxicity is unknown. We investigated the potential neurodevelopmental toxicity of ipconazole pesticides in zebrafish (Danio rerio). Our behavioral monitoring demonstrated that the locomotive activity of ipconazole-exposed zebrafish larvae was reduced during early development, even when morphological abnormalities were undetected. Molecular profiling demonstrated that the mitochondrial-specific antioxidants, superoxide dismutases 1 and 2, and the genes essential for mitochondrial genome maintenance and functions were specifically reduced in ipconazole-treated (0.02 µg/mL) embryos, suggesting underlying ipconazole-driven oxidative stress. Consistently, ipconazole treatment substantially reduced hsp70 expression and increased ERK1/2 phosphorylation in a dose-dependent manner. Interrupted gad1b expression confirmed that GABAergic inhibitory neurons were dysregulated at 0.02 µg/mL ipconazole, whereas glutamatergic excitatory and dopaminergic neurons remained unaffected, resulting in an uncoordinated neural network. Additionally, ipconazole-treated (2 µg/mL) embryos exhibited caspase-independent cell death. This suggests that ipconazole has the potential to alter neurodevelopment by dysregulating mitochondrial homeostasis.

Association of biofilm production with multidrug resistance among clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosa from intensive care unit.

BACKGROUND AND AIMS: Given choice, bacteria prefer a community-based, surface-bound colony to an individual existence. The inclination for bacteria to become surface bound is so ubiquitous in diverse ecosystems that it suggests a strong survival strategy and selective advantage for surface dwellers over their free-ranging counterparts. Virtually any surface, biotic or abiotic (animal, mineral, or vegetable) is suitable for bacterial colonization and biofilm formation. Thus, a biofilm is "a functional consortium of microorganisms organized within an extensive exopolymeric matrix." MATERIALS AND METHODS: The present study was undertaken to detect biofilm production from the repertoire stocks of Acinetobacter baumannii (A. baumannii) and Pseudomonas aeruginosa (P. aeruginosa) obtained from clinical specimens. The tube method was performed to qualitatively detect biofilm production. RESULTS: A total of 109 isolates of both organisms were included in the study, out of which 42% (46/109) isolates showed biofilm detection. Among the biofilm producers, 57% of P. aeruginosa and 73% of A. baumannii showed multidrug resistance (MDR) pattern which was statistically significant in comparison to nonbiofilm producers (P < 0.001). CONCLUSION: To the best of our knowledge, this is the only study to have tested the biofilm production in both P. aeruginosa and A. baumannii in a single study. Biofilm production and MDR pattern were found to be significantly higher in A. baumannii than P. aeruginosa. Antibiotic resistance was significantly higher among biofilm producing P. aeruginosa than non producers. Similarly, antibiotic resistance was significantly higher among biofilm producing A. baumannii than non producers.

Differential Neuroprotective Effects of N-Acetylcysteine against Dithianon Toxicity in Glutamatergic, Dopaminergic, and GABAergic Neurons: Assessment Using Zebrafish.

Despite the widespread agricultural use of dithianon as an antifungal agent, its neurotoxic implications for humans and wildlife have not been comprehensively explored. Using zebrafish embryonic development as our model, we found that dithianon treatment induced behavioral alterations in zebrafish larvae that appeared normal. Detailed quantitative analyses showed that dithianon at ≥0.0001 µgmL-1 induced cytoplasmic and mitochondrial antioxidant responses sequentially, followed by the disruption of mitochondrial and cellular homeostasis. Additionally, dithianon at 0.01 and 0.1 µgmL-1 downregulated the expressions of glutamatergic (slc17a6b), GABAergic (gad1b), and dopaminergic (th) neuronal markers. Contrarily, dithianon upregulated the expression of the oligodendrocyte marker (olig2) at concentrations of 0.001 and 0.01 µgmL-1, concurrently suppressing the gene expression of the glucose transporter slc2a1a/glut1. Particularly, dithianon-induced increase in reactive oxygen species (ROS) production was reduced by both N-acetylcysteine (NAC) and betaine; however, only NAC prevented dithianon-induced mortality of zebrafish embryos. Moreover, NAC specifically prevented dithianon-induced alterations in glutamatergic and dopaminergic neurons while leaving GABAergic neurons unaffected, demonstrating that the major neurotransmission systems in the central nervous system differentially respond to the protective effects. Our findings contribute to a better understanding of the neurotoxic potential of dithianon and to developing preventive strategies.

Ecology of Bloodstream Infections and Temporal Trends of Their Antibiograms with Respect to Source and Duration of Incubation: A 5-Year Retrospective Observational Analysis.

Purpose Blood is one of the most important connective tissues of human body. Bloodstream infection can range from inapparent bacteremia till fulminant septic shock with high mortality. Presence of microbes in blood whether continuously, intermittently, or transiently is a grave risk to every organ of body. Culture of blood is a vital tool to diagnose such infections. Drug susceptibility patterns help in rationalizing therapy. Objective The aim of the study is to perform bacteriological analysis and assess drug sensitivity patterns of blood culture isolates and compare in light of other associated variables. Design Retrospective observational study was conducted from January 2009 to December 2013 at a tertiary care hospital at Shillong, India. Blood samples were collected with aseptic guidelines and cultured for 7 days. Growths were identified by standard biochemical tests and subjected to sensitivity testing according to Modified Kirby Bauer disk diffusion method. Data for source of blood collection and duration of incubation were noted and compared. Results A total of 658 (11.2%) pathogens were isolated from 5,867 bacteremia-suspected patient blood specimens. Contamination was observed at the rate of 1.21%. Gram-negative organisms were the predominant pathogens recovered, Klebsiella pneumoniae being the most common. No significant difference was observed between the number of organisms isolated within or beyond 48 hours. Acinetobacter baumannii and K. pneumoniae have significantly higher chances ( p < 0.05) of isolation from central line catheters compared with peripheral venipuncture. Conclusion Successful treatment of sepsis depends on early diagnosis and proper antimicrobial therapy. Local knowledge of bacteriological profile and antimicrobial sensitivity patterns helps rationalize empiric treatment strategies.

Bloodstream infections and trends of antimicrobial sensitivity patterns at Port Blair.

PURPOSE: Bloodstream infection can range from inapparent bacteremia until fulminant septic shock with high mortality. Microorganisms present in circulating blood whether continuously, intermittently, or transiently are a threat to every organ in the body. Culture of blood is a vital tool to diagnose such infections. Drug susceptibility patterns help in rationalizing therapy. OBJECTIVE: The objective of this study was to perform bacteriological analysis and assess drug sensitivity patterns of isolates from blood stream infections. DESIGN: Retrospective observational study was conducted from May 2015 to February 2017 at a tertiary care hospital, Port Blair, India. Blood samples were collected with aseptic guidelines and cultured for 7 days. Growths were identified using standard biochemical tests and subjected to sensitivity testing according to Modified Kirby-Bauer's disk diffusion method. Data for the source of blood collection and duration of incubation were noted and compared. RESULTS: A total of 270 (14.24%) pathogens were isolated from 1895 bacteremia suspect patient blood specimens. Contamination was observed at a rate of 1.63%. Gram-positive cocci (60.37%) were predominant organisms recovered followed by Gram-negative Bacilli (36.29%) and Yeasts (3.33%). Staphylococcus aureus, CoNS, and Acinetobacter spp. were the primary pathogens isolated. Aminoglycosides, carbapenems, and glycopeptides were the most effective drugs for treating bacteremia. CONCLUSIONS: Successful treatment of sepsis depends on early diagnosis and proper antimicrobial therapy. Local knowledge of bacteriological profile and antimicrobial sensitivity patterns helps rationalize empiric treatment strategies.

Clinico-aetiologic profile of Onychomycoses in a tertiary care centre in northeast India.

Onychomycosis refers to fungal nail infection. Despite a clearly diseased appearance, it is often deemed a merely cosmetic problem of relatively minor importance. However, it may result in much psychological or occupational turmoil, diminished self-esteem and resulting reluctance for public interaction. A wide number of factors determine the treatment outcome and its prevalence varies greatly. Our study was conducted between January 2011 and December 2014 in northeast India. Of 243 patients presenting with nail abnormalities, 158 (65%) were positively diagnosed by either direct microscopy or culture or both. A distal lateral subungual infection was the most predominant clinical pattern observed, and the most frequent aetiological agents were dermatophytes, of which Trichophyton rubrum was predominant.

Inducible and constitutive clindamycin resistance in Staphylococcus aureus in a northeastern Indian tertiary care hospital.

INTRODUCTION: Staphylococcus aureus is one of the most common pyogenic bacteria. They are notorious for developing prompt resistance to newer antimicrobials. With increasing incidence of methicillin-resistant S. aureus (MRSA) isolates, the treatment options are also becoming limited. Clindamycin is an excellent drug for skin and soft tissue infections, but resistance mediated by the inducible phenotype (iMLS(B)) leads to in vivo therapeutic failure even though there may be in vitro susceptibility. The double disk approximation test (D-test) can reliably detect the presence of such isolates. This study was aimed to detect and report the prevalence of the iMLS(B) phenotype in NEIGRIHMS, a tertiary care center in Northeast India. METHODOLOGY: A total of 243 consecutive isolates were subjected to routine identification tests followed by antimicrobial sensitivity testing. Erythromycin-resistant isolates were tested for inducible resistance phenotype by the D-test. RESULTS: Among strains tested, 95 (39%) were erythromycin resistant. Twenty-six (10.7%) isolates were D-test positive (iMLS(B) phenotype), 41 (16.88%) were constitutively resistant (cMLS(B) phenotype), and 28 isolates (11.52%) were found to be negative by D-test. The incidence of both inducible and constitutive phenotypes was higher in MRSA isolates compared to methicillin-sensitive S. aureus (MSSA) isolates. CONCLUSIONS: This study revealed a moderate prevalence of the inducible clindamycin phenotype in the staphylococcal isolates tested. Clinical microbiology laboratories in areas of high MRSA prevalence should consider performing the D-test routinely. This will help prevent prescription of drug(s) whose therapeutic efficacy is doubtful.