Members of a new subgroup of Streptococcus anginosus harbor virulence related genes previously observed in Streptococcus pyogenes.

Conventionally categorized as commensals, the Streptococci of the species S. anginosus are facultative human pathogens that are difficult to diagnose and often overlooked. Furthermore, detailed investigation and diagnosis of S. anginosus infections is hampered by unexplored taxonomy and widely elusive molecular pathogenesis. To explore their pathogenic potential, S. anginosus isolates collected from patients of two geographical locations (Vellore, India and Leipzig, Germany) were subjected to multi-locus sequence analysis (MLSA). This analysis revealed the potential presence of a new distinct clade of the species S. anginosus, tentatively termed here as genomosubspecies vellorensis. A complementary PCR-based screening for S. pyogenes virulence factor as well as antibiotic resistance genes revealed not only the presence of superantigen- and extracellular DNase coding genes identical to corresponding genes of S. pyogenes, but also of erythromycin and tetracycline resistance genes in the genomes of the analyzed S. anginosus isolates, thus posing a matter of significant health concern. Identification of new pathogenic S. anginosus strains capable of causing difficult to treat infections may pose additional challenges to the diagnosis and treatment of Streptococcus based infections.

Absence of zygomycetes in the oral niche of patients with oral squamous cell carcinoma and oral potentially malignant disorders.

Mucormycosis is a fungal infection which has been regrouped under emerging infectious disease. In this COVID-19 pandemic, the incidence of mucormycosis has been reported in many parts of India. Systemic condition that weakens one's immune systems like uncontrolled diabetes, chemotherapy or chronic long-term illness poses a grave threat for this fungal infection. Patients with oral cancer and precancer remain at significant risk for developing severe infections regardless of significant developments in therapy. Few studies have reported that this opportunistic fungal pathogen may be cultured from the oral cavity. Our findings disprove the oral carriage of filamentous fungi (Zygomycetes) among the group of patients with oral squamous cell carcinoma, oral potentially malignant disorders who are susceptible to immunological deficits and healthy subjects. This finding strongly supports that the oral niche of healthy as well as the patients with oral lesions do not harbour this filamentous fungi.

A comparative study of Candida species diversity among patients with oral squamous cell carcinoma and oral potentially malignant disorders.

OBJECTIVES: To determine the prevalence of Candida species by PCR-RFLP method in the saliva of patients with oral squamous cell carcinoma (OSCC), oral potentially malignant disorders (OPMD) and healthy cohorts. Unstimulated saliva was collected from patients with OSCC (n = 97), OPMD (n = 200), and healthy controls (n = 200). Candida species were isolated using the standard protocol. The isolates were identified using phenotypic and genotypic methods. The odds/risk ratio was calculated using Pearson's Chi-square test. The significance of Candidal carriage was calculated by independent T-test. RESULTS: Oral Candidal carriage was 72.2%, 58% and 20.5% among patients with OSCC, OPMD, and healthy controls respectively. The oral Candidal carriage in OSCC and OPMD was highly significant (p = 0.0001). Non albicans Candida predominated over Candida albicans. Candida species were diverse among the study groups with a predominance of Candida krusei, Candida tropicalis, and Pichia anomala formerly Candida pelliculosa. P. anomala occurrence outnumbered in health. The odds/risk ratio for OSCC and OPMD were 4.25/11.87 and 3.52/6.99 respectively. A high prevalence of non albicans Candida was observed both in all the three groups (OSCC, OPMD and healthy controls). High odds and risk ratio associates Candida species to OSCC and OPMD. Candida famata may be associated with OSCC and OPMD.