Journal of Advances in Microbiology

Clinicomycological Evaluation and Therapeutic Management of Secondary Malassezia pachydermatis Dermatitis Associated with Generalized Demodicosis in Dog

Thu, 20 Aug 2026 00:00:00 +0000

Aim: To describe the clinicomycological, cytological, antifungal susceptibility and therapeutic findings of secondary Malassezia pachydermatis dermatitis associated with generalised demodicosis in a Pug and to emphasise the importance of an integrated diagnostic and therapeutic approach.

Presentation of case: An 8-year-old female Pug weighing 8.5 kg was presented with a 6-month history of generalised pruritus, alopecia, greasy seborrhoea, hyperpigmentation, lichenification and characteristic foul odour. Generalised demodicosis was diagnosed based on deep skin scrapings. Cutaneous cytology using Diff-Quik and New Methylene Blue staining revealed numerous budding yeast cells suggestive of Malassezia spp. Fungal culture followed by phenotypic characterisation confirmed the isolate as Malassezia pachydermatis, while antifungal susceptibility testing by the disc diffusion method supported the selection of itraconazole for systemic therapy. The dog was treated with an isoxazoline-based acaricide for generalised demodicosis, along with oral itraconazole and topical chlorhexidine–miconazole shampoo. Supportive treatment was also provided. The treatment resulted in the resolution of the cutaneous lesions and progressive hair regrowth, with complete clinical recovery. The dog was followed for one month after completion of treatment, during which no recurrence of dermatological lesions was observed.

Discussion: Generalised demodicosis may predispose dogs to secondary Malassezia overgrowth through disruption of the skin barrier and alteration of local immune responses. A combination of parasitological, cytological and mycological investigations facilitates a definitive diagnosis, while antifungal susceptibility testing may assist in selecting appropriate therapy. Concurrent treatment of the underlying demodicosis and secondary Malassezia dermatitis is important for achieving clinical resolution and reducing the risk of recurrence.

Conclusion: This case highlights the usefulness of integrated clinicomycological, parasitological and cytological investigations in the diagnosis and management of canine Malassezia dermatitis associated with generalised demodicosis. Early recognition and concurrent treatment of both conditions resulted in complete clinical resolution, with no recurrence observed during the one-month follow-up period.

Genotype-dependent Germination and Rhizophagus irregularis-associated Biomass Responses to NaCl in B73 and West African EV8728SR Maize Lines

Tue, 18 Aug 2026 00:00:00 +0000

Aims: To determine how maize genotype, Rhizophagus irregularis inoculum, and NaCl affect germination and seedling performance, while distinguishing inoculum effects before root colonisation from responses after mycorrhizal establishment.
Study Design: A 2 × 2 × 3 factorial experiment compared B73 and EV8728SR, R. irregularis inoculum or a non-mycorrhizal control, and 0, 68, or 102 mM NaCl.

Place and Duration of Study: The five-day germination assay and subsequent greenhouse experiment were conducted at the Institut National Polytechnique Félix Houphouët-Boigny, Yamoussoukro, Côte d’Ivoire.

Methodology: The germination assay used three independent dishes per combination; most greenhouse endpoints used 11 independent pots per combination. Responses included final germination, mean germination time (MGT), germination speed index (GSI), biomass, morphology, chlorophyll, electrolyte leakage, tissue water content, and root colonisation. Endpoint-appropriate factorial models and Tukey-adjusted comparisons were applied.

Results: Final germination was statistically uninformative. EV8728SR germinated faster than B73 (MGT and GSI, P < 0.001), and GSI declined with NaCl (P = 0.019). Total dry biomass showed effects of genotype (P < 0.001), inoculum (P = 0.007), and NaCl (P < 0.001), with no significant interactions. At 102 mM, the descriptive Ri-associated biomass differences were 40.7% in B73 and 38.2% in EV8728SR. Mycorrhization intensity declined with NaCl (P = 0.011).

Conclusion: EV8728SR was the stronger-performing genotype, and Ri inoculation produced a modest average biomass benefit. Because interactions were not significant, the larger percentage differences at severe salinity are descriptive. Germination responses represent the inoculum treatment, not established symbiosis.

Pathogenic Bacteria Associated with Urinary Tract Infections in Men

Charles E. Deutch — Fri, 28 Aug 2026 00:00:00 +0000

Urinary tract infections are among the most common diseases in humans. Uncomplicated and complicated infections can occur in both male and female patients, but they are much less common in men. Although the signs and symptoms of UTIs in men are similar to those in women, they are most often due to anatomical abnormalities, prostatic hyperplasia, or insertion of a catheter. In addition to causing inflammation of the urethra, bladder, and kidneys, bacterial infections in men may also cause prostatitis. This review focuses on UTIs in males with the goals of determining whether there are unique features of the pathogenic bacteria that cause them and stimulating further research in this area. The normal urinary microbiome in males is different from that in females and contains several urotypes. Among the most common urinary tract pathogens are the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa, along with the Gram-positive bacteria Enterococcus faecalis and Staphylococcus saprophyticus. These bacteria produce a large number of virulence factors, including adhesive pili, various surface proteins, metal ion acquisition systems, and flagella. The ability of many pathogens to form biofilms on host cells or urinary catheters may contribute to both uncomplicated and complicated UTIs. Uropathogenic E. coli (UPEC) is the most common and best-studied cause of both uncomplicated and complicated UTIs. While no specific strain of this bacterium appears to cause UTIs in men, combinations of virulence factors in certain clonal groups are found more often in male patients. Other less well-studied bacteria, including some corynebacteria, Francisella species, mycoplasmas, campylobacteria, and streptococci, may be more frequently associated with UTIs in men than in women and deserve further analysis. In addition to more microbiological studies, specific research on the cell biology and immunology of the male urinary system would be helpful in understanding the unique features of UTIs in men.

Phytochemical Constituents of Euphorbia hirta Extracts and Their Antifungal Activity against Dermatophytic and Non-dermatophytic Fungi from Human Skin Scrapings

Wed, 12 Aug 2026 00:00:00 +0000

Euphorbia hirta is widely used in traditional medicine for the treatment of superficial fungal infections. This study evaluated the phytochemical composition, antifungal activity, and synergistic effects of extracts obtained from the leaves, flowers, stem bark, and roots of E. hirta against dermatophytic and non-dermatophytic fungi isolated from human skin scrapings. Plant extracts were prepared using water, hexane, and chloroform as extraction solvents. Qualitative and quantitative phytochemical analyses were performed, while antifungal activity was assessed using the agar well diffusion method, minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and extract-combination assays to evaluate synergistic activity. The highest extraction yield (47.43%) was obtained from the chloroform flower extract. Phytochemical analysis revealed a high phenolic content, with the leaf extract containing 417.46 ± 0.02 mg/g. Several extracts demonstrated notable antifungal activity. None of the chloroform extracts inhibited all the test isolates across the concentrations evaluated. Hexane extracts showed no activity against Aspergillus fumigatus, whereas only the hexane stem bark extract inhibited Aspergillus niger at 1000 mg/mL, producing an inhibition zone of 18.12 ± 0.14 mm. Trichophyton interdigitale was inhibited by the hexane leaf extract at 500 mg/mL, with an inhibition zone of 14.08 ± 0.17 mm. Aqueous extracts showed no activity against the Aspergillus isolates but inhibited T. interdigitale at concentrations ranging from 250 to 1000 mg/mL. Combinations of the extracts exhibited antifungal activity against A. niger and T. interdigitale. MIC values ranged from 120 mg/mL to >1000 mg/mL, while MFC values ranged from 125 mg/mL to >1000 mg/mL. These findings demonstrate that E. hirta possesses antifungal activity, particularly against T. interdigitale, and exhibits measurable synergistic effects when extract combinations are used. The presence of bioactive phytochemicals further supports the potential of E. hirta extracts as natural antifungal agents or adjunct therapies for the management of dermatophytic and non-dermatophytic fungal infections.

Pathogenicity and Antibiotic Resistance of Bacteria Isolated from Reused Dish-rinsing Water in Informal Restaurants in Daloa (Côte d’Ivoire)

Wed, 12 Aug 2026 00:00:00 +0000

Background: In Daloa (Côte d’Ivoire), the reuse of dish-rinsing water in informal (street food) restaurants is a common practice that may constitute a major source of microbial contamination and the dissemination of antibiotic-resistant bacteria.

Aims: This study assessed the physicochemical and microbiological quality of such water, identified the bacterial species present, and analysed their resistance profiles.

Place and Duration of Study: The research was conducted at the Laboratory of Agrovalorisation, Department of Biochemistry-Microbiology, Jean LOROUGNON GUEDE University of Daloa, from February 2025 to March 2025.

Methodology: Thirty samples collected from ten restaurants in the Tazibouo district were analysed for pH, mesophilic aerobic germs (MAG), total coliforms, Escherichia coli, Salmonella spp., and Staphylococcus aureus. Isolates were identified using biochemical methods and tested for antibiotic susceptibility according to EUCAST (2025) guidelines. Resistance genes for β-lactams (bla_TEM, bla_SHV, bla_CTX-M), quinolones (qnrA, qnrB, qnrS), colistin (mcr-1) were detected by PCR.

Results: The results showed that 40% of the samples had a pH outside the recommended range and that most exceeded microbiological standards; Salmonella spp. was present in 10%, E. coli in 70%, and S. aureus in 80% of the samples. Klebsiella oxytoca was the predominant species (66.66%) and displayed complete resistance to amoxicillin-clavulanic acid and, in 29% of cases, resistance to fluoroquinolones and chloramphenicol. The most frequently detected resistance genes were bla_TEM and qnrA, whereas mcr-1 was not found.

Conclusion: These findings indicate that reused dish-rinsing water in these establishments is a potential reservoir of multidrug-resistant bacteria and poses a significant public health risk, underscoring the urgent need to improve hygiene practices, increase the frequency of water replacement, and implement regular monitoring.

Isolation, Molecular Characterization, and Screening for Hydrocarbon-degrading Potential of an Indigenous Enterobacter sp. from Petroleum-contaminated Soil for Bioremediation Applications

Deepthi Kiran, M. Bhavani, M. Vedhashree, U. Keerthi, K. V. Chandrika — Wed, 19 Aug 2026 00:00:00 +0000

Petroleum hydrocarbon contamination creates ecological risks and motivates sustainable remediation strategies. This study isolated indigenous oil-degrading bacteria from petroleum-contaminated soils and screened their relative hydrocarbon-degrading potential. Four soil samples were collected from automobile-workshop sites in and around Bengaluru and Chikkaballapur, Karnataka, India. Samples were enriched in Bushnell–Haas minimal salt medium supplemented with 3% (v/v) used engine oil as the sole carbon source. Eight isolates were obtained and screened using an agar well diffusion clearance-zone assay. Morphological and biochemical characterisation was followed by 16S rRNA gene sequencing of the most active isolate. Isolate K2 produced the largest clearance zone (30 mm), followed by C2 (25 mm) and K3 (20 mm), whereas W1 and S1 produced 5 mm zones. BLASTn and phylogenetic analysis placed K2 within the Enterobacter cloacae complex, with 99.93% sequence identity to reference sequences in GenBank. The results indicate that indigenous bacteria from chronically hydrocarbon-contaminated soils can show differing relative activities under the screening conditions, with K2 displaying the strongest response among the isolates tested. Because the agar well diffusion assay does not directly quantify hydrocarbon removal, the observed clearance zones should be interpreted as a relative screening measure. Quantitative gravimetric or chromatographic analyses, together with soil-based validation, are required before the degradation efficiency and bioremediation applicability of K2 can be established.

Phenotypic Characterization and Molecular Identification of Pseudomonas aeruginosa Isolated from Clinical Samples

Mon, 24 Aug 2026 00:00:00 +0000

Pseudomonas aeruginosa is an important opportunistic pathogen associated with diverse clinical infections. This study aimed to isolate and phenotypically characterize P. aeruginosa from clinical samples collected from dogs with dermatological conditions and to isolate and identify using molecular methods. Fifty clinical samples comprising wound, pus, otitis externa, and dermatitis swabs were collected during April–May 2025. Samples were enriched in BHI broth, cultured on cetrimide agar, and presumptive isolates were assessed using cultural and microscopic characteristics. All presumptive isolates were subsequently subjected to PCR amplification targeting the 16S rRNA and rpoB genes. Five presumptive P. aeruginosa isolates were recovered from the 50 samples, corresponding to an isolation frequency of 10.0% (5/50). The isolates exhibited cultural and microscopic characteristics consistent with P. aeruginosa, including characteristic colony morphology, pigmentation, fluorescence under ultraviolet illumination, and Gram-negative rod-shaped morphology. PCR amplification produced the expected 618 bp 16S rRNA and 759 bp rpoB amplicons in all five isolates. These findings indicate that conventional phenotypic characterisation combined with dual-target PCR can provide practical molecular support for the identification of presumptive P. aeruginosa isolates from canine dermatological clinical samples.

Synthesis of (E)-N2-(3-Methylquinoxalin -2-yl)-N5-(1-Phenylethylidene) Pyridine-2,5-Diamine Derivatives and Evaluation of Their Antimicrobial Activity

Wed, 26 Aug 2026 00:00:00 +0000

Background: Research on the synthesis of various quinoxaline derivatives has gained significant attention due to their remarkable chemical and biological properties. These compounds exhibit diverse reactivity, making them valuable in chemical synthesis, and they also show promising potential in medicinal chemistry, with applications in the development of new drugs. Consequently, ongoing studies focus on exploring novel methods to synthesize quinoxalines efficiently, aiming to enhance their therapeutic potential and broaden their scope in pharmaceutical and industrial applications.

Objective: This study aimed to synthesize a series of (E)-N2-(3-methylquinoxalin-2-yl)-N5-(1-phenylethylidene) pyridine-2,5-diamine derivatives and evaluate their antimicrobial activity against various bacterial strains.

Materials and Methods: Some (E)-N2-(3-methylquinoxalin-2-yl)-N5-(1-phenylethylidene) pyridine-2,5-diamine derivatives were synthesized via condensation reactions between N²-(3-methylquinoxalin-2-yl) pyridine-2,5-diamine and various substituted acetophenones. The compounds were tested for their potential antibacterial properties.

Results: The synthesised compounds demonstrated a broad spectrum of antibacterial activity against ten different clinically isolated bacterial strains. The minimum inhibitory concentration (MIC) values for these compounds varied between 0.00781 mg/mL and 0.0625 mg/mL, indicating their potent ability to inhibit bacterial growth at low concentrations. Additionally, the minimum bactericidal concentration (MBC) values ranged from 0.0156 mg/mL to 0.125 mg/mL, further highlighting their effectiveness in completely eradicating the bacteria. This broad-spectrum activity suggests that the compounds could potentially be effective against various bacterial infections, making them promising candidates for further development as antimicrobial agents.

Discussion and Conclusion: The study concluded that the synthesized (E)-N2-(3-methylquinoxalin-2-yl)-N5-(1-phenylethylidene) pyridine-2,5-diamine derivatives were bactericidal towards the clinically isolated bacterial strains and could therefore serve as potential broad-spectrum bactericidal agents to combat the development of multiple resistance by pathogens to available antimicrobial agents.

Screening and Characterization of Native Microbial Antagonists for the Development of a Multi-Strain Biocontrol Consortium against Ralstonia solanacearum

B. J. Praveen Biradar, R. N. Lakshmipathi — Fri, 28 Aug 2026 00:00:00 +0000

Bacterial wilt caused by Ralstonia solanacearum remains difficult to manage sustainably, creating a need for compatible native microbial antagonists with complementary biocontrol traits. This study isolated four rhizosphere microorganisms—Trichoderma viride (Tv), Pseudomonas fluorescens (Pf), Bacillus subtilis (Bs) and Azotobacter chroococcum (Ac)—from healthy eggplant plants surviving in bacterial-wilt-affected fields and assessed their antagonistic, biochemical, plant-growth-associated and compatibility characteristics. In dual-culture assays, Pf showed the highest inhibition of R. solanacearum (68.50%; 18.40 mm inhibition zone), followed by Bs (55.40%; 15.60 mm). Hydrolytic enzyme screening indicated overlapping amylase, protease and lipase activities among the antagonists, with Bs showing a 16.5 mm protease clearance zone and Pf a 14.2 mm zone. Siderophore screening showed the largest CAS halo for Pf (22.40 mm), which also exhibited a strong positive reaction for HCN production. Ac produced the highest indole-3-acetic acid concentration (32.60 µg/ml), followed by Pf (28.40 µg/ml). Cross-streak assays showed no visible inter-strain inhibition among Tv, Pf, Bs and Ac under the tested conditions. These findings indicate complementary in vitro functional traits and preliminary mutual compatibility among the four isolates, supporting their further evaluation as candidate components of a multi-strain biocontrol consortium. Molecular identification, formulation assessment and greenhouse and field validation remain necessary before practical application.

Synthesis of N,N-Dibenzyl-2-(2-Benzylidenehydrazinyl)-3-oxo-3,4-Dihydroquinoxaline-6-Sulfonamide Derivatives and Evaluation of Their Antimicrobial Activity

Sat, 29 Aug 2026 00:00:00 +0000

Quinoxaline derivatives are of considerable interest because of their diverse chemical and biological properties. This study Synthesized N,N-dibenzyl-2-(2-benzylidenehydrazinyl)-3-oxo-3,4-dihydroquinoxaline-6-sulfonamide derivatives and evaluated their antibacterial activity against selected clinically isolated bacterial strains. The target compounds were prepared through condensation reactions between N,N-dibenzyl-2-hydrazinyl-3-oxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide and substituted aromatic aldehydes. Structural characterization was performed using infrared, ¹H NMR, and ¹³C NMR spectroscopic methods. Antibacterial activity was assessed by the agar-well diffusion method, while minimum inhibitory concentration and minimum bactericidal concentration assays were used to further evaluate antimicrobial activity. All eight Synthesized derivatives, designated 1a–1h, inhibited the growth of the ten bacterial isolates tested. The inhibition zones recorded for the Synthesized compounds ranged from 18 to 49 mm. Their minimum inhibitory concentrations ranged from 0.00781 to 0.0625 mg/mL, compared with 0.125 mg/mL for streptomycin and 0.250 mg/mL for tetracycline. Minimum bactericidal concentration testing also indicated bactericidal activity against the tested isolates. Under the reported in vitro conditions, the Synthesized N,N-dibenzyl quinoxaline-6-sulfonamide derivatives demonstrated broad antibacterial activity against both Gram-positive and Gram-negative bacterial isolates. These findings support further investigation of this compound series while remaining limited to the experimental conditions used in the present study.