Mycobacterium tuberculosis H37Rv is a highly successful pathogen and its success fully relies on its ability to utilize macrophages for its replication and, more importantly, the macrophage should remain viable to host the Mycobacterium. Despite the fact that these phagocytes are usually very effective in internalizing and clearing most of the bacteria, M. tuberculosis H37Rv has evolved a number of very effective survival strategies, including: (a) the inhibition of phagosome–lysosome fusion; (b) the inhibition of phagosome acidification; (c) the recruitment and retention of tryptophan‐aspartate containing coat protein on phagosomes to prevent their delivery to lysosomes; and (d) the expression of members of the host‐induced repetitive glycine‐rich protein family of proteins. However, the mechanisms by which M. tuberculosis H37Rv enters the host cell, circumvents host defenses and spreads to neighboring cell are not completely understood. Therefore, a better understanding of host–pathogen interaction is essential if the global tuberculosis pandemic is ever to be controlled. This review addresses some of the pathogenic strategies of the M. tuberculosis H37Rv that aids in its survival and pathogenicity.

The current study determined the spectrum of biliary microflora with special emphasis on enteric fever organisms in patients with acute cholangitis with and without cholelithiasis or other biliary diseases. The patients were divided into three groups: Group A consisted of patients with acute cholecystitis with cholelithiasis; Group B consisted of patients with acute cholecystitis with gastrointestinal ailments requiring biliary drainage and group C consisted of patients with gallbladder carcinoma. Gallbladder, bile and gallstones were subjected to complete microbiological and histopathological examination. Antimicrobial susceptibility of the isolates was performed as per CLSI guidelines. Bacteria were recovered from 17 samples (32%) in Group A, 17 (51.4%) in Group B and 1 (1.6%) in Group C. The most common organisms isolated were Escherichia coli (11, 29.7%), Klebsiella pneumoniae (10, 27%), Citrobacter freundii (3, 8.1%), Salmonella enterica serovar Typhi (3, 8.1%), etc. The majority of Enterobacteriaceae isolates were susceptible to piperacillin-tazobactam and meropenem. As regards Salmonella spp., S. Typhi was isolated from 2 (3.8%) patients in Group A and 1 (16%) in Group C. Antimicrobial susceptibility of potential causative organisms, the severity of the cholecystitis, and the local susceptibility pattern must be taken into consideration when prescribing drugs. A protocol regarding the management of such cases should be formulated based on observations of similar studies.

Mycobacterium tuberculosis is the causative agent of tuberculosis disease, which has developed a myriad of exceptional features contributing to its survival within the hostile environment of host cell. Unique cell wall structure with high lipid content plays an imperative role in the pathogenicity of mycobacteria. Cell wall components of MTB such as lipoarabinomannan and Trehalose dimycolate (cord factor) are virulent in nature apart from its virulence genes. Virulent effect of these factors on host cells reduces host cell immunity. LAM has been known to inhibit phagosome maturation by inhibiting the Ca2+/calmodulin phosphatidyl inositol-3-kinase hvps34 pathways. Moreover, TDM (Trehalose dimycolate) also inhibits fusion between phospholipid vesicles and migration of polymorphonuclear neutrophils. The objective of this paper is to understand the virulence of LAM and cord factor on host cell which might be helpful to design an effective drug against tuberculosis.

We report three cases of rhinosporidiosis from migrant population of Delhi. Three male patients had sino-nasopharyngeal, nasopharyngeal and nasal rhinosporidiosis, respectively. One patient gave a history of bathing in stagnant water. The diagnosis was made by clinical presentation and microscopic observation of characteristic sporangia of Rhinosporidium seebri in mycological and histopathological investigations. All the patients were successfully treated with complete surgical excision of lesions and cauterization of base. There were no recurrences.