An Atypical Pathogen at an Atypical Location: A Rare Case of Salmonella-Associated Submandibular Abscess.

Salmonella infections commonly cause gastroenteritis and enteric fever but can also result in extraintestinal infections, especially in immunocompromised individuals. Although rare, Salmonella infection in the head and neck region was found to be more common in diabetics and patients with malignancy. We present a unique case of a 52-year-old immunocompromised man with uncontrolled diabetes who developed a submandibular abscess due to Salmonella Paratyphi B. The patient initially presented with pain, swelling, and difficulty swallowing, which worsened over a week. Diagnostic imaging revealed a well-defined abscess with lymphadenopathy. Management included incision and drainage, followed by identification of Salmonella Paratyphi B and targeted antibiotic therapy based on culture and sensitivity analysis. This case highlights the importance of early recognition, appropriate diagnostic imaging, and targeted antimicrobial therapy in managing uncommon manifestations of Salmonella infection in the head and neck. Continued vigilance and multidisciplinary management are essential for favorable patient outcomes in such cases.

Molecular Characterization of High-Level Aminoglycoside Resistance among Enterococcus Species.

Background Enterococci are nosocomial pathogen. They can develop high-level resistance to aminoglycoside by producing aminoglycoside modifying enzymes (AMEs). In enterococci, high level resistance to aminoglycosides is mediated by acquisition of plasmid mediated genes encoding for aminoglycoside modifying enzymes (AMEs). High level gentamicin resistance (MIC ≥ 500µg /mL) is predominantly mediated by aac(6')-Ie-aph(2″)-Ia, encoding the bifunctional aminoglycoside modifying enzyme AAC(6')-APH(2″). This enzyme eliminates the synergistic activity of gentamicin when combined with a cell wall active agent. Other AME genes such as aph(2″)-Ib, aph(2″)-Ic, aph(2″)-Id and ant(4')-1a have also been detected in enterococci. Objective This study was carried out to determine the diverse prevalence of AME and their pattern of occurrence in the clinical isolates of Enterococci . Materials and Methods A total number of 150 clinical isolates were included in this study. Susceptibility to various antibiotics was determined by disc diffusion. Minimum Inhibitory Concentration (MIC) was ascertained by agar dilution method. Polymerase chain reaction was done to screen the following AMEs (aac(6')-Ie-aph(2″)-Ia; aph(2″)-Ib; aph(2″)-Ic; aph(2″)-Id and aph(3')- IIIa genes) . Results 51.3% of the study isolates exhibited high level gentamicin resistance. Polymerase chain reaction revealed that aph(3')-111a is the most prevalent AME, followed by aac(6')-1e-aph(2″)-1a . The combination of both the genes were detected in 44.1% of the study isolates. The rest of the AMEs and their combinations were not encountered in this study. 8.6% of the study isolates did not harbour any AME genes screened for, but was phenotypically resistant to gentamicin. In contrast 31.3% anchored the AME genes but phenotypically appeared susceptible to gentamicin. Conclusion This study indicates the high- level aminoglycoside resistance disseminated among Enterococci in our geographical region. It also emphasizes the detection of AMEs by PCR is mandatory because strains that appear susceptible by disc diffusion and/or MIC method may harbour one or more AMEs genes leading to therapeutic failure.

Pulmonary Infections Caused by Emerging Pathogenic Species of Nocardia.

Pulmonary infections are the most common clinical manifestations of Nocardia species. There is an increase in cases of nocardial infections occurring worldwide attributable to the increase in the immunosuppressed population. The availability of molecular methods has aided the detection of more number of cases as well as unusual species. Still, it remains one of the most underdiagnosed pathogens. Recognition of drug resistance in this organism has now mandated early and precise identification with speciation for effective treatment and management. Nocardial species identity can predict antimicrobial susceptibility and guide clinical management. Here, we report two cases of pulmonary nocardiosis caused by unusual species of Nocardia, namely, N. cyriacigeorgica and N. beijingensis identified by 16S rRNA gene-based sequencing. These cases are being reported for their rarity.