Infectious diseases caused by clinically important Mycobacteria continue to be an important public health problem worldwide primarily due to emergence of drug resistance crisis. In recent years, the control of tuberculosis (TB), the disease caused by Mycobacterium tuberculosis (MTB), is hampered by the emergence of multidrug resistance (MDR), defined as resistance to at least isoniazid (INH) and rifampicin (RIF), two key drugs in the treatment of the disease. Despite the availability of curative anti-TB therapy, inappropriate and inadequate treatment has allowed MTB to acquire resistance to the most important anti-TB drugs. Likewise, for most mycobacteria other than MTB, the outcome of drug treatment is poor and is likely related to the high levels of antibiotic resistance. Thus, a better knowledge of the underlying mechanisms of drug resistance in mycobacteria could aid not only to select the best therapeutic options but also to develop novel drugs that can overwhelm the existing resist¬ance mechanisms. In this article, we review the distinctive mechanisms of antibiotic resistance in mycobacteria.

Probiotics are live microbial food supplements or their components, which have been shown to have beneficial effects on human health. Probiotics can be bacteria, molds, or yeasts, but most of them fall into the group known as lactic acid bacteria and are normally consumed in the form of yogurt, fermented milk, or other fermented foods. Data from clinical trials have shown contrasting effects and should be interpreted with caution. A large variety of potential beneficial effects have been reported including improvement of intestinal tract health, enhancing the immune system, reducing symptoms of lactose intolerance, decreasing the prevalence of allergy in susceptible individuals, reducing risk of certain cancers, treating colitis, lowering serum cholesterol concentrations, reducing blood pressure in hypertensives, and improving female urogenital infections and Helicobacter pylori infections. The aim of this article is to present a review of the current expanding knowledge of applications of utilizing probiotic microorganisms in the prevention and treatment of several diseases.

New Delhi metallo-beta-lactamase (NDM-1) is a novel metallo-beta-lactamase (MBL). Sporadic cases of NDM-1 positive strains have been reported from different countries, suggesting a widespread dissemination. The aim of this study was the detection of MBLs in Enterobacteriaceae isolated from patients in Tehran hospitals. After identification tests, the susceptibility to the antibiotics was done by Kirby–Bauer method and broth microdilution. Carbapenem-resistant isolates were tested for carbapenemase production using the modified Hodge test (MHT). Carbapenem-resistant strains screened for bla _KPC gene and genes encoding MBLs. Twenty-three isolates (6.3%) were resistant to meropenem, eleven isolates (3%) were resistant to ertapenem, and four isolates (1.1%) were resistant to imipenem. MHT was positive in 11 (47.8%) of the carbapenem-resistant isolates. In March 2011, we detected a multiple drug-resistant Klebsiella pneumoniae isolate that was resistant to all tested antibiotics except colistin. PCR confirmed that this isolate contained bla _NDM-1 , bla _TEM , bla _SHV , and bla _CTX-M . This is the first report on the detection of MBL NDM-1 in Iran. The rapid spread of NDM-1-positive bacteria proved to be a major challenge for the treatment and control of infectious diseases.

An exosome is a nano vesicle that buds from the endosomal compartment; it is produced and released by all kinds of mammalian cells. This vesicle contains a variety of proteins, lipids, mRNAs and miRNAs. These components are specific to the origin of the exosomes and contribute to cell-cell communications. Recently, it has been reported that a few single cell eukaryotic pathogens such as Cryptoccoccus neoformance and Leishmania major and donovanican secrete an exosome and influence the host immune system. In addition, it has been observed that cells infected by intracellular pathogens are capable of secreting an exosome which is involved in the fate of the infection. Furthermore, retroviruses recruit the host`s endosomal compartments in order to generate viral vesicles which are similar to the exosome. Most of the exosomes involved in infectious biology can either spread or limit an infection based on the type of pathogen and its target cells. Hence, an exosome may be an appropriate candidate for a vaccine therapy in prophylaxis and treatment.