The genus mycobacterium includes several species that are known to cause infections in humans. The microorganisms are classified into tuberculous and non-tuberculous based on their morphological characteristics, defined by the dynamic relationship between the host defenses and the infectious agent. Non-tuberculous mycobacteria (NTM) include all the species of mycobacterium other than the ones that cause tuberculosis (TB). The group of NTM contains almost 200 different species and they are found in soil, water, animals—both domestic and wild—milk and food products, and from plumbed water resources such as sewers and showerhead sprays. A systematic review of Medline between 1946 and 2014 showed an 81% decline in TB incidence rates with a simultaneous 94% increase in infections caused by NTM. Prevalence of infections due to NTM has increased relative to infections caused by TB owing to the stringent prevention and control programs in Western countries such as the USA and Canada. While the spread of typical mycobacterial infections such as TB and leprosy involves human contact, NTM seem to spread easily from the environment without the risk of acquiring from a human contact except in the case of M. abscessus in patients with cystic fibrosis, where human transmission as well as transmission through fomites and aerosols has been recorded. NTM are opportunistic in their infectious processes, making immunocompromised individuals such as those with other systemic infections such as HIV, immunodeficiencies, pulmonary disease, or usage of medications such as long-term corticosteroids/TNF-α inhibitors more susceptible. This review provides insight on pathogenesis, treatment, and BCG vaccine efficacy against M. leprae and some important NTM infections.

Mixed neuroendocrine–nonneuroendocrine epithelial neoplasms are rare malignant neoplasms that may occur in the bladder with highly aggressive behavior. Because of its worse prognosis, when compared to the pure urothelial carcinoma without the neuroendocrine component, the bladder mixed neuroendocrine–nonneuroendocrine epithelial neoplasm may be considered a distinct clinicopathologic entity. We present a case of mixed neuroendocrine–nonneuroendocrine epithelial neoplasm occurring in the urinary bladder of an elderly female with a personal history of chronic kidney disease, drug-resistant urinary tract infections, and neurogenic bladder. Her presenting symptoms included complaints of abdominal pain, urinary urgency, oliguria, dysuria, and occasional hematuria. Recognition of the clinicopathologic features of these rare aggressive neoplasms is important for accurate early diagnosis, necessitating appropriate therapeutic management.

Pseudomembranes in the large and small intestines are common in hospitalized patients that are immunosuppressed or on certain oral antibiotics. Pseudomembranous enterocolitis, histologically characterized by volcanic-like eruption of inflammatory cellular exudate from the mucosal surface, is mainly attributed to Clostridium difficile toxins and often presents with symptomatic diarrhea. Rarely, there are case reports of similar pseudomembranous lesions limited to the stomach in the absence of intestinal involvement. In this paper, we present a case of localized pseudomembranous gastritis in a 76-year-old patient with personal history limited to prior gastrointestinal bleed, liver cirrhosis, alcohol dependence, diabetes mellitus, and hypertension who was referred to the emergency department from his primary care physician’s office due to low hemoglobin.