Synthesis of ciprofloxacin-linked 1,2,3-triazole conjugates as potent antibacterial agents using click chemistry: exploring their function as DNA gyrase inhibitors via in silico- and in vitro-based studies.

The antibacterial efficacy of some newly developed C-3 carboxylic group-containing ciprofloxacin-linked 1,2,3-triazole conjugates was studied. Twenty-one compounds from three different series of triazoles were synthesized using click chemistry and evaluated for their antibacterial activity against nine different pathogenic strains, including three Gram-positive strains, i.e. Enterococcus faecalis (ATCC29212), Staphylococcus aureus (ATCC25923), Staphylococcus epidermidis (clinical isolate), and six Gram-negative bacterial strains, i.e. Escherichia coli (ATCC25922), Pseudomonas aeruginosa (ATCC27853), Salmonella typhi (clinical isolate), Proteus mirabilis (clinical isolate), Acinetobacter baumannii (clinical isolate) and Klebsiella pneumonia (clinical isolate). Among the compounds, 10, 10a, 10b, 10c, 10d, 11a, 11f, 12c, 12e and 12f showed excellent activity with MIC values upto 12.5 µg mL-1, whereas the control ciprofloxacin showed MIC values of 0.781-25 µg mL-1 towards various strains. In addition, the low toxicity profile of the synthesized molecules revealed that they are potent antibiotics. Molecular docking and MD analysis were performed using the protein structure of E. coli DNA gyrase B, which was further corroborated with an in vitro assay to evaluate the inhibition of DNA gyrase. The analysis revealed that compound 10b was the most potent inhibitor of DNA gyrase compared to ciprofloxacin, which was employed as the positive control. Furthermore, the structure of two title compounds (11a and 12d) was characterized using single-crystal analysis.

Fabrication of gelatin coated polycaprolactone nanofiber scaffolds co-loaded with luliconazole and naringenin for treatment of Candida infected diabetic wounds.

The current study focuses on the development of gelatin-coated polycaprolactone (PCL) nanofibers co-loaded with luliconazole and naringenin for accelerated healing of infected diabetic wounds. Inherently, PCL nanofibers have excellent biocompatibility and biodegradation profiles but lack bioadhesion characteristics, which limits their use as dressing materials. So, coating them with a biocompatible and hydrophilic material like gelatin can improve bioadhesion. The preparation of nanofibers was done with the electrospinning technique. The solid state characterization and in-vitro performance assessment of nanofibers indicate the formation of uniformly interconnected nanofibers of 200-400 nm in diameter with smooth surface topography, excellent drug entrapment, and a surface pH of 5.6-6.8. The antifungal study showed that the nanofiber matrix exhibits excellent biofilm inhibition activity against several strains of Candida. Further, in-vivo assessment of nanofiber performance on C. albicans infected wounds in diabetic rats indicated accelerated wound healing efficacy in comparison to gauge-treated groups. Additionally, a higher blood flow and rapid re-epithelialization of wound tissue in the treatment group corroborated with the results obtained in the wound closure study. Overall, the developed dual-drug-loaded electrospun nanofiber mats have good compatibility, surface properties, and excellent wound healing potential, which can provide an extra edge in the management of complex diabetic wounds.

Formulation and characterization of polyvinyl alcohol/chitosan composite nanofiber co-loaded with silver nanoparticle & luliconazole encapsulated poly lactic-co-glycolic acid nanoparticle for treatment of diabetic foot ulcer.

Chronic wounds are prone to fungal infections, possess a significant challenge, and result in substantial mortality. Diabetic wounds infected with Candida strains are extremely common. It can create biofilm at the wound site, which can lead to antibiotic resistance. As a result, developing innovative dressing materials that combat fungal infections while also providing wound healing is a viable strategy to treat infected wounds and address the issue of antibiotic resistance. Present work proposed anti-infective dressing material for the treatment of fungal strains Candida-infected diabetic foot ulcer (DFU). The nanofiber was fabricated using polyvinyl Alcohol/chitosan as hydrogel base and co-loaded with silver nanoparticles (AgNP) and luliconazole-nanoparticles (LZNP) nanoparticles, prepared using PLGA. Fabricated nanofibers had pH close to target area and exhibited hydrophilic surface suitable for adhesion to wound area. The nanofibers showed strong antifungal and antibiofilm properties against different strains of Candida; mainly C. albicans, C. auris, C. krusei, C. parapsilosis and C. tropicalis. Nanofibers exhibited excellent water retention potential and water vapour transmission rate. The nanofibers had sufficient payload capacity towards AgNP and LZNP, and provided controlled release of payload, which was also confirmed by in-vivo imaging. In-vitro studies confirmed the biocompatibility and enhanced proliferation of Human keratinocytes cells (HaCaT). In-vivo studies showed accelerated wound closure by providing ant-infective action, supporting cellular proliferation and improving blood flow, all collectively contributing in expedited wound healing.

Screening for cryptococcal antigen in asymptomatic people with HIV: urgent need in Eastern India.

OBJECTIVE: Cryptococcal meningitis (CM) is a leading cause of mortality in people with HIV (PWH). Despite recommendation by the National programme, cryptococcal antigen (CrAg) screening in PWH with CD4 + <200/µl has not been implemented in practice. Therefore, we conducted a prospective study in government funded Antiretroviral treatment centre to determine the prevalence of asymptomatic cryptococcal antigenemia in PWH with CD4 + cell count <200 cells/µl, subclinical cryptococcal meningitis in serum CrAg positive subjects and their outcome. METHOD: Serum CrAg (BIOSYNEX CryptoPS) screening was conducted in newly diagnosed asymptomatic retro-positive adults with CD4 + <200/µl between January 2021 and March 2022. We also conducted cerebrospinal fluid (CSF) CrAg testing in all PWH who were serum CrAg positive and appropriate therapy was instituted. All the enrolled participants were followed up till February 2023. RESULT: Among enrolled 142 PWH patients, 22 (15.49%) were positive for serum CrAg. Among these 22, seven (31.8%) patients had CD4 + cell count between 100 and 199 cells/µl. CSF CrAg was positive in 11 (50%) serum CrAg positive cases. Serum CrAg positivity was significantly associated with low CD4 + cell count, poor clinical stage and concomitant Pneumocystis pneumonia. However, mortality was not significantly different in Serum CrAg positive and negative PWH. None of the deaths in CrAg positive PWH was due to cryptococcal disease. CONCLUSION: Higher prevalence of cryptococcal antigenemia and subclinical CM among PWH with CD4 + cell count <200 cells/µl with good treatment outcomes with therapy reiterates the need for CrAg screening among PWH in Eastern India.

Rhizopus homothallicus rhino-orbital-cerebral mucormycosis: Six cases from a tertiary care Centre, North India.

OBJECTIVE: To report six cases of Rhizopus homothallicus rhino-orbital-cerebral mucormycosis in North India between April 2021 and July 2021. CASE DETAILS: All six patients had diabetes, concomitant SARS-CoV-2 infection, a history of oxygen requirement and steroid intake. Among these six cases 4 were female. All patients presented with sinus pain and peri-orbital swelling. COVID-19-associated mucormycosis (CAM) was diagnosed based on microbiological examination of the biopsied tissue, and its staging was determined radiologically by CT and MRI. Three patients were in stage III-C, the others were in stage II-C, II-D and IV-A. A multidisciplinary team treated the patients with extensive surgical debridement of the affected tissue, correction of predisposing comorbidities and administration of an antifungal agents. Patients were followed up for 6 months with routine direct nasal endoscopy to check the sinonasal cavity for any recurrence. All the six patients survived at 6 months of follow-up. CONCLUSION: A timely initiated multidisciplinary team-based approach can reduce the mortality in rhino-orbital-cerebral mucormycosis cases caused by R. homothallicus.

Time to speed up the diagnostic evaluation in clinically suspected rhinosinusitis patients: A debate on the conventional versus molecular workup to establish fungal infective etiology for prompt management.

Background and Purpose: Rhinosinusitis (RS) is a clinical and radiological diagnosis that rarely reaches a proper infective etiological diagnosis. The most dreaded fact about invasive fungal rhinosinusitis is its poor prognosis in immunocompromised patients with a 60-80% mortality rate. The present study highlights and compares the various diagnostic techniques to establish a fungal etiological diagnosis in clinically suspected cases of RS from nasal biopsy specimens, with the emphasis on the molecular diagnostic approach. Materials and Methods: This prospective study included a total of 34 clinically suspected cases of RS who had recently undergone functional endoscopic sinus surgery (FESS)/biopsy from nasal polyps. Various laboratory methods (microbiological and histopathological) were utilized, including direct microscopic examination of clinical samples and fungal culture isolation. The molecular detection method of polymerase chain reaction (PCR) from clinical samples was also explored simultaneously. Serum immunoglobulin-E (IgE) testing of patients was also performed. Results: Out of 34 clinically suspected RS cases, fungal etiology was established in a total of 18 cases, 17 of whom were culture-proven. A total of 15 and 14 culture-proven cases were also detected on direct microscopic examination by potassium hydroxide (KOH) mount and histopathological staining, respectively. One case was additionally identified by molecular method. Aspergillus flavus complex was the most common pathogen isolated in culture. Allergic fungal RS was the most common type, followed by acute and chronic invasive types among all fungal RS cases. Conclusion: Accurate and prompt etiological diagnosis of fungal RS is still lagging with fewer options for quick results. Although microscopy and culture isolation can't be replaced, PCR is a sensitive and specific method that should be incorporated as a supplementary tool for the early diagnosis and management, considering the delayed growth of fungi.

COVID-19-associated Mucormycosis: A clinico-epidemiological study.

BACKGROUND: There was an unprecedented increase in COVID-19-associated-Mucormycosis (CAM) cases during the second pandemic wave in India. METHODS: This observational study was done to know the epidemiological profile of CAM cases andincluded all patients admitted with mucormycosis between May 2021 and July 2021. RESULTS: Out of the enrolled 208 CAM cases (either SARS-CoV-2 RT-PCR or serology positive), 204, three and one had rhino-orbital-cerebral, pulmonary and gastrointestinal mucormycosis, respectively. 95.7 % of the patients had diabetes, out of which 42.3 % were recently diagnosed. Mean HbA1c was 10.16 ± 2.56 %. 82.5 % of the patients were unvaccinated. During their COVID-19 illness, 86.5 % were prescribed antibiotics, 84.6 % zinc preparations, 76.4 % ivermectin, and 64.9 % steroids, while only 39.5 % required oxygen therapy. The frequency of blood groups A, B, O and AB in our CAM patients was 29.5 %, 18.9 %, 38.9 % &12.6 %, respectively. At three months follow up, 60 (28.8 %) patients died, four (1.9 %) stopped antifungal treatment, and 144(69.23 %) were on antifungal treatment. 55 % (n = 33) of deaths occurred within 15 days of admission. Mortality was significantly associated with higher age, RT-PCR positive for SARS-CoV-2, raised serum creatinine and alkaline phosphatase during treatment. At 6 months follow-up, eight more patients died, three due to chronic kidney disease, four patients who had stopped treatment and one patient who was on a ventilator due to COVID-19 associated pneumonia and the rest 140(67.3 %) survived. CONCLUSION: Uncontrolled hyperglycemia, SARS-CoV-2 infection, rampant use of antibiotics, zinc supplementation and steroids were some of the risk factors for mucormycosis. Despite the overwhelming number of patients with an uncommon disease like mucormycosis, the six months mortality was much lower than expected.

Size and Zeta Potential Clicked Germination Attenuation and Anti-Sporangiospores Activity of PEI-Functionalized Silver Nanoparticles against COVID-19 Associated Mucorales (Rhizopus arrhizus).

The SARS-CoV-2 infections in Indian people have been associated with a mucormycotic fungal infection caused by the filamentous fungi Rhizopus arrhizus. The sporangiospores of R. arrhizus are omnipresent in the environment and cause infection through inhalation or ingestion of contaminated air and foods. Therefore, the anti-sporangiospore activity of polyethyleneimine functionalized silver nanoparticles (PEI-f-Ag-NPs) with variable size and surface charge as a function of the molecular weight of PEI was explored. The results showed that both PEI-f-AgNP-1 and PEI-f-AgNP-2, potentially, attenuated the germination and reduced the viability of sporangiospores. Furthermore, the results showed that the minimum inhibitory concentration (MIC) values of both PEI-f-AgNP-1 and PEI-f-AgNP-2 (1.65 and 6.50 µg/mL, respectively) were dependent on the nanoparticle size and surface ζ potentials. Similarly, the sporangiospore germination inhibition at MIC values was recorded, showing 97.33% and 94% germination inhibition, respectively, by PEI-f-AgNP-1 and 2 within 24 h, respectively. The confocal laser scanning microscopy, SEM-EDS, and confocal Raman spectroscopy investigation of PEI-f-Ag-NPs treated sporangiospores confirmed size and surface charge-dependent killing dynamics in sporangiospores. To the best of our knowledge, this is the first investigation of the polyethyleneimine functionalized silver nanoparticle-mediated size and surface charge-dependent anti-sporangiospore activity against R. arrhizus, along with a possible antifungal mechanism.

Laboratory diagnosis of mucormycosis: Present perspective.

Upsurge in mucormycosis cases in the second wave of SARS CoV2 infection in India has been reported. Uncontrolled diabetes is the major predisposing risk factor for these cases. The early diagnosis and surgical intervention with medical treatment may result in good clinical outcomes. The glycaemic control in diabetic patients also favours better treatment outcome in patients suffering from mucormycosis.

Tubo-ovarian mass with raised CA-125 in a 21-year-old female.

INTRODUCTION: Peritonitis associated with fungal species Curvularia lunata seldom occurs with only five cases reported in the literature, all in middle-age patients with comorbidities undergoing dialysis. CASE REPORT: A 21-year-old female who was referred to surgical oncology OPD with a diagnosis of ovarian malignancy, based on raised cancer antigen 125 (CA 125) and suspected tubo-ovarian mass (TOM) on magnetic resonance imaging (MRI). A review of the MRI showed a pelvic collection with TOM, suggestive of infective pathology. Fungal culture and mass spectroscopy of the cystic collection identified the presence of Curvularia lunata. She was treated with oral itraconazole which showed symptomatic improvement and radiological response. In the follow-up period, the patient developed chest wall swelling, aspiration and geneXpert® revealed multidrug-resistant (MDR) tuberculosis, and treatment was started. CONCLUSIONS: Unusual causes of TOM and raised CA 125 should be kept in mind when dealing with young patients, as the possibility of epithelial ovarian cancer in this age is very low.

Fatal Cutaneous Mucormycosis Caused by Apophysomyces elegans: A Case Report and Review of Literature.

Primary cutaneous mucormycosis is a consequence of environmental Mucorales spores inoculation at the abraded skin. In a diabetic patient, these spores germinate quickly and disseminate hematogenously to the surroundings. Cutaneous mucormycosis is a rare but aggressive, invasive, and life-threatening fungal infection. Its presentation is nonspecific, but it rapidly results in necrosis of underneath tissues. Diagnosis can be readily made by KOH wet mount of excise tissue. However, a prompt diagnosis with multidisciplinary management is a prerequisite for a better outcome. We present a case of fatal cutaneous mucormycosis caused by Apophysomyces elegans, in a diabetic patient who succumbed to death despite extensive debridement and antifungal treatment.

Targeted and Enhanced Antimicrobial Inhibition of Mesoporous ZnO-Ag2O/Ag, ZnO-CuO, and ZnO-SnO2 Composite Nanoparticles.

In this work, mesoporous (pore size below 4 nm) composite nanoparticles of ZnO-Ag2O/Ag, ZnO-CuO, and ZnO-SnO2 of size d ≤ 10 nm (dia.) have been synthesized through the in situ solvochemical reduction method using NaBH4. These composite nanoparticles exhibited excellent killing efficacy against Gram-positive/negative bacterial and fungal strains even at a very low dose of 0.010 µg/mL. Additionally, by applying the in silico docking approach, the nanoparticles and microorganism-specific targeted proteins and their interactions have been identified to explain the best anti-bacterial/anti-fungal activities of these composites. For this purpose, the virulence and resistance causing target proteins such as PqsR, RstA, FosA, and Hsp90 of Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Candida albicans have been identified to find out the best inhibitory action mechanisms involved. From the in vitro study, it is revealed that all the composite nanoparticle types used here can act as potent antimicrobial components. All the composite nanoparticles have exhibited excellent inhibition against the microorganisms compared to their constituent single metal or metal oxide nanoparticles. Among the nanoparticle types, the ZnO-Ag2O/Ag composite nanoparticles exhibited the best inhibition activity compared to the other reported nanoparticles. The microorganisms which are associated with severe infections lead to the multidrug resistance and have become a huge concern in the healthcare sector. Conventional organic antibiotics are less stable at a higher temperature. Therefore, based on the current demands, this work has been focused on designing inorganic antibiotics which possess stability even under harsh conditions. In this direction, our developed composite nanoparticles were explored for potential uses in the healthcare technology, and they may solve many problems in global emergency and epidemics caused by the microorganisms.

Anacardic acid encapsulated solid lipid nanoparticles for Staphylococcus aureus biofilm therapy: chitosan and DNase coating improves antimicrobial activity.

Biofilm mediated bacterial infections are the key factors in the progression of infectious diseases due to the evolution of antimicrobial resistance. Traditional therapy involving antibiotics is not adequate enough for treatment of such infections due to the increased resistance triggered by biofilm. To overcome this challenge, we developed anacardic acid (Ana) loaded solid lipid nanoparticles (SLNs), further coated with chitosan and DNase (Ana-SLNs-CH-DNase). The DNase coating was hypothesized to degrade the e-DNA, while chitosan was coated to yield positively charged SLNs with additional adhesion to biofilms. The SLNs were developed using homogenization method and further evaluated for particle size, polydispersity index, zeta potential, and entrapment efficiency. Drug excipient compatibility was confirmed by using FT-IR study, while encapsulation of Ana in SLNs was confirmed by X-ray diffraction study. The SLNs demonstrated sustained release for up to 24 h and excellent stability at room temperature for up to 3 months. The developed SLNs were found non-toxic against human immortalized keratinocyte (HaCaT) cells while demonstrated remarkably higher antimicrobial efficacy against Staphylococcus aureus. Excellent effect of the developed SLNs on minimum biofilm inhibition concentration and minimum biofilm eradication concentration further confirmed the superiority of the developed formulation strategy. A significant (p < 0.05) reduction in biofilm thickness and biomass, as confirmed by confocal laser scanning microscopy, was observed in the case of developed SLNs in comparison with control. Cumulatively, the results suggest the enhanced efficacy of the developed formulation strategy to overcome the biofilm-mediated antimicrobial resistance. Graphical abstract.

Targeted specific inhibition of bacterial and Candida species by mesoporous Ag/Sn-SnO2 composite nanoparticles: in silico and in vitro investigation.

Invasive bacterial and fungal infections have notably increased the burden on the health care system and especially in immune compromised patients. These invasive bacterial and fungal species mimic and interact with the host extracellular matrix and increase the adhesion and internalization into the host system. Further, increased resistance of traditional antibiotics/antifungal drugs led to the demand for other therapeutics and preventive measures. Presently, metallic nanoparticles have wide applications in health care sectors. The present study has been designed to evaluate the advantage of Ag/Sn-SnO2 composite nanoparticles over the single oxide/metallic nanoparticles. By using in silico molecular docking approaches, herein we have evaluated the effects of Ag/Sn-SnO2 nanoparticles on adhesion and invasion responsible molecular targets such as LpfD (E. coli), Als3 (C. albicans) and on virulence/resistance causing PqsR (P. aeruginosa), RstA (Bmfr) (A. baumannii), FoxA (K. pneumonia), Hsp90 and Cyp51 (C. albicans). These Ag/Sn-SnO2 nanoparticles exhibited higher antimicrobial activities, especially against the C. albicans, which are the highest ever reported results. Further, Ag/Sn-SnO2 NPs exhibited interaction with the heme proionate residues such as Lys143, His468, Tyr132, Arg381, Phe105, Gly465, Gly464, Ile471 and Ile304 by forming hydrogen bonds with the Arg 381 residue of lanosterol 1 4α-demethylase and increased the inhibition of the Candida strains. Additionally, the Ag/Sn-SnO2 nanoparticles exhibited extraordinary inhibitory properties by targeting different proteins of bacteria and Candida species followed by several molecular pathways which indicated that it can be used to eliminate the resistance to traditional antibiotics.

Utility of nested polymerase chain reaction for fungus in detecting clinically suspected patients of invasive fungal infections and its clinical correlation and comparison with fungal culture.

AIMS AND OBJECTIVES: The aim and objective of this study is to detect invasive fungal infections (IFIs) early and with more sensitivity by the nested polymerase chain reaction (PCR) for fungus as compared to fungal culture in clinically suspected patients and also explore its correlation in reference to age, duration of symptoms, immunocompromised status, and other risk factors predisposing to IFIs. MATERIALS AND METHODS: In this cross-sectional study, 50 suspected patients admitted in medical acute care unit/intensive care unit (ACU/ICU) of Sir Sunderlal Hospital, Banaras Hindu University, Varanasi, India, comprised the study. All cases were selected based on the predefined inclusion and exclusion criteria. A detailed history, clinical examination, and all required investigations were done in all suspected patients. Blood samples were taken for nested-PCR for fungus and culture. Nested PCR was performed on extracted DNA form samples collected from all participants under the study. RESULTS: Our study comprised of 50 suspected immunocompromised patients of IFIs. Among the participants under the study, the most common risk factor was diabetes mellitus (28% cases). Nearly two-thirds (60%) of the cases were 50 years or more. Around 70% of the cases had a history of illness more than 2 weeks. Nested PCR for fungus came out to be positive in 21/50 patients (42%); however, fungal culture was positive in none. Among the admitted patient in ACU/ICU, 75% were neutropenic. CONCLUSIONS: IFIs are more common in immunocompromised individuals, patients with comorbidities, long history of symptoms, and elderly population. Nested PCR for fungus has a high sensitivity (as compared to the fungal culture), and also they are rapid in giving the results. Thus, nested PCR for fungus can be used in a cost-effective manner for the early and reliable diagnosis of clinically suspected IFIs.

The utility of banana peel extract agar in the presumptive identification of Cryptococcus neoformans.

We prepared a newer growth medium, banana peel extract agar (BPEA) containing the extracts of chopped banana peels for the selective cultivation of Cryptococcus neoformans. Over the medium, the growth resulted in the development of light to the dark brown coloured colonies indicating the chromogenic potential of the BPEA. The organism grown over BPEA was subsequently confirmed as C. neoformans by phenotypic as well as by molecular method. This medium, being cost-effective, may be used in resource-poor settings of the developing or underdeveloped countries for selective isolation of C. neoformans.

Efficacy of Terbinafine and Itraconazole in Different Doses and in Combination in the Treatment of Tinea Infection: A Randomized Controlled Parallel Group Open Labeled Trial with Clinico-Mycological Correlation.

BACKGROUND: There is a rising prevalence of dermatophyte infection especially in the tropics. It has been observed that the antifungals are not as effective as they used to be. AIMS: To determine the effectiveness of terbinafine and itraconazole in different doses and in combination in the treatment of tinea infection. MATERIALS AND METHODS: Study design was a randomized parallel group trial. Patients were randomly divided into five parallel arms in which two of the standard drugs in recommended doses were compared with their double doses and with combination of both the drugs. Patients were followed up every 2 weeks. Outcomes were assessed at 4 and 8 weeks. Cure was considered as complete clinical resolution of the lesions. Fungal culture and sensitivity were done by disk diffusion method for all patients. Parametric one-way analysis of variance (F test) and Chi-square test were used for the analysis. RESULTS: Two-hundred seventy-five patients were included in the study. Itraconazole containing groups showed significantly higher cure rates than terbinafine only groups both at 4 and 8 weeks (P < 0.001). Itraconazole containing groups, when compared against each other, were not found to be significantly different. The outcomes between terbinafine only groups were also not significantly different. Cure rates at 8 weeks were found to be greater than that at 4 weeks for all groups which were found to be highly significant (P < 0.001). CONCLUSIONS: Itraconazole seems to be more effective than terbinafine. There is no benefit in increasing the dose or using a combination regimen in the treatment of tinea. Prolonged duration of treatment is required for complete cure.

Overexpression of efflux pump transporter genes and mutations in ERG11 pave the way to fluconazole resistance in Candida tropicalis: A study from a North India region.

INTRODUCTION: Fluconazole resistance in Candida tropicalis health care-associated infections is increasing. We investigated the role of efflux pump and mutations in ERG11p conferring fluconazole resistance in C. tropicalis. MATERIALS AND METHODS: A total of 17 C. tropicalis clinical isolates, including fluconazole-resistant and fluconazole-susceptible/fluconazole-susceptible dose-dependent isolates, were collected from a tertiary care centre in a North India region between 2015 and 2018. Antifungal susceptibility, reversal of fluconazole resistance by tacrolimus, ERG11 amplification and its sequencing and a quantitative polymerase chain reaction (PCR) assay for expression analysis of ERG11, MDR1 and CDR1 genes were performed. RESULTS AND DISCUSSION: Synergism between fluconazole and tacrolimus was observed in all resistant C. tropicalis isolates. Overexpression of all the three genes, MDR1, ERG11 and CDR1, was observed in resistant isolates (P = 0.05). Among resistant isolates, mutations leading to amino acid substitution were seen in two, Ct10 (glysine464serine) and Ct16 (tyrosine132phenylalanine; serine154phenylalanine). CONCLUSION: Overexpression in efflux pump transporter genes, together with mutations in ERG11, lead to fluconazole resistance among C. tropicalis. To the best of our knowledge, this is the first study on the C. tropicalis fluconazole resistance mechanism from the North India region.