Acta Microbiologica Hellenica

Dermatophilosis, caused by the Gram-positive, filamentous bacterium Dermatophilus congolensis, is an important skin disease that adversely affects cattle health and productivity. It also affects other domestic and wild animals and occasionally humans. This review provides a detailed overview of the molecular characteristics and resistome profile of D. congolensis, highlighting recent advances in genomic research. We examine the bacterium’s genome architecture, including its genome size, GC content, gene composition, and phylogenetic placement within the Actinomycetales. Key virulence factors are discussed, including proteolytic enzymes, hyphal invasion, zoospore motility, and the gene products of nasp and agac, emphasizing their roles in tissue invasion, pathogenesis, and diagnostic detection. Furthermore, we analyze resistome, focusing on identified antibiotic resistance genes, diverse resistance mechanisms such as efflux pumps and beta-lactamases, and the contribution of mobile genetic elements to horizontal gene transfer. The implications of these molecular insights for accurate diagnosis, effective treatment, and antibiotic stewardship in cattle production are critically evaluated. Finally, we highlight future research priorities aimed at deepening our understanding of D. congolensis biology and improving strategies for disease control. This review underscores the importance of integrating molecular surveillance with antimicrobial monitoring to safeguard cattle health and promote sustainable livestock management.

Worldwide, polymicrobial infections (PMIs) account for an estimated 20–50% of severe clinical infection cases, with biofilm-associated and device-related infections reaching 60–80% in hospitalized patients. This review discusses the clinical burden of major infections in which PMIs are almost inevitable, such as diabetic foot infections, intra-abdominal infections, pneumonia, and biofilm-associated device infections. Globally, the PMI landscape is diverse; however, the Indian subcontinent is a PMI hotspot where high comorbidities, endemic antimicrobial resistance, and underdeveloped diagnostic capacity elevate the risks of poor outcomes. Existing diagnostic like culture-based methods, PCR panels, sequencing, and biomarker-based assays are constrained by sensitivity, turnaround times (TATs), and high costs. Vulnerable populations, particularly neonates, the elderly, immunocompromised patients, and socioeconomically marginalized groups, show case-fatality rates 2-fold higher than monomicrobial infections in similar settings. Emerging diagnostic solutions include CRISPR-based multiplex assays, artificial intelligence-based metagenomic platforms, and sensitive biosensors with point-of-care applicability. These technologies show potential in reducing the TAT (<2 h) with high accuracy (>95%). However, their translation to real-world settings depends critically on affordability, integration into healthcare pathways, and supportive policy. This will provide equitable diagnostic access, particularly in low- and middle-income countries (LMICs).

Age-related impaired wounds often become infected with bacteria, leading to substantial mortality and morbidity in the elderly. The decline in androgen levels with increasing age is believed to exacerbate inflammation during wound infections. Despite its well-documented anti-inflammatory activities in wound repair, little is known about the effect of age-related androgen deprivation on bacterial phagocytosis in impaired chronic wounds. The aim of this study was to investigate the effect of age-related testosterone deprivation on the phagocytic functions of THP-1 monocyte-derived macrophages to eliminate Gram-positive and Gram-negative bacteria in vitro. Host–pathogen interaction experiments were conducted to quantify the macrophage-mediated clearance of two common wound-associated bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, under in vitro environments that model testosterone levels representative of those found in elderly males, healthy young adults and testosterone replacement therapy (TRT). Testosterone and its metabolite 5α-dihydrotestosterone (DHT) significantly dampened the macrophage-mediated phagocytosis of both MRSA and P. aeruginosa in a dose-dependent manner (p < 0.05). Blockade of the androgen receptor (AR) using enzalutamide confirmed that testosterone mediates bacterial clearance through binding to the AR. Blocking the conversion of testosterone to DHT through stimulation of macrophages with the 5-α-reductase inhibitor finasteride reversed the testosterone-mediated effects on bacterial clearance, which confirmed that testosterone could potentially dampen the innate phagocytic responses in macrophages through conversion to DHT. Novel findings in this study suggest that the selective manipulation of the AR and/or blockade of testosterone–DHT conversion may provide effective therapeutic treatments to combat wound infections in the elderly.