supplement and human health benefits through prevention and controlling of bacterial infections.

The emergence of antibiotic-resistant bacterial strains has become a global crisis and is vulnerable for the exploration of alternative antibacterial therapies. The present study emphasizes the use of bacteriophage for the treatment of multidrug resistant P. aeruginosa. P. aeruginosa was used to induce septicemia in streptozotocin (STZ) induced diabetic and nondiabetic mice by intraperitoneal (i.p.) injection of 3 × 108 CFU, resulting in a fatal bacteremia within 48 hrs. A single i.p. injection of 3 × 109 PFU phage GNCP showed efficient protection in both diabetic (90%) and nondiabetic (100%) bacteremic mice. It was further noted that the protection rate was reduced in diabetic mice when phage GNCP was administered after 4 h and 6 h of lethal bacterial challenge. In contrast, nondiabetic bacteremic mice were rescued even when treatment was delayed up to 20 h after lethal bacterial challenge. Evaluation of results confirmed that a single intraperitoneal injection of the phage dose (3 × 109 PFU/mL) was more effective than the multiple doses of imipenem. These results uphold the efficacy of phage therapy against pernicious P. aeruginosa infections, especially in cases of immunocompromised host.

In the present investigation we report unique biological green synthesis of nanoparticles (AgNPs) by secondary metabolites of Streptomyces supernatant extract acting as reducing agents in hydrothermal process. Various divergent techniques like sonication, microven, heating and hydrothermal (autoclaving) techniques were employed to produce silver nanoparticles through microbe-mediated assistance. The Streptomyces sp. GUT 21 was isolated from the field soil sampled neighbouring the campus of Gulbarga University. Morphological and biochemical characterization of the strain was performed and its taxonomical genus identification was determined by 16s rDNA technique. The formation of nanoparticles was first monitored by measuring the surface plasmon resonance (SPR) band at 410 nm through UV-Visible absorption spectroscopy. FTIR analysis revealed that many efficient clusters of functional biomolecules are playing significant role in capping and synthesis process during hydrothermal method. The crystalline structure of the AgNPs and the presence of elemental silver nanoparticles were confirmed by powder X-ray diffraction (PXRD) and scanning electron microscopy. Our results indicated that, nanoparticles are spherical in shape with an average of 23-48 nm in size. The biosynthesized AgNPs exhibited significant antibacterial activity against Escherichia coli (MTCC 9537), Klebsiella pneumoniae (MTCC 109), Pseudomonas aeruginosa (MTCC1688) and Staphylococcus aureus (MTCC 96). This biotechnological development of synthesis of nanoparticles can further be exploited as ''new-generation of antimicrobials'' against multi-drug resistant bacteria (MDR) for various medical diagnostic applications.

Multi drug resistant Klebsiella pneumoniae showed stepwise adaptation when grown in increasing concentration of Cefotaxime eventually reaching a maximum of 2 mg/ml. The resultant Cefotaxime resistant mutant strain was stable and did not revert to susceptibility on frequent subculturing. The response of the cells to different concentration of Cefotaxime was examined by scanning electron microscope which showed that the size of the bacterium increased with increasing concentration of Cefotaxime.

A methicillin-susceptible strain of Staphylococcus aureus (MSSA) showed stepwise adaptation when grown in increasing concentrations of oxacillin, eventually reaching a maximum of 35 lg/ml. The resultant oxacillin resistant mutant strain was stable and did not revert to susceptibility on frequent subculturing. The response of the cells to different concentrations of oxacillin was examined by scanning electron microscopy, which showed that the size of the bacterium increased with increasing concentrations of oxacillin. These changes in cell size were dependent on the concentration of oxacillin and occurred only after addition of non-lethal concentrations. In the presence of lethal concentrations ( ‡35 lg/ml) that completely inhibited cell growth, the cell sizes were smaller than those of wild-type cells and irregular in shape. This stepwise-adapted methicillin (oxacillin) resistant S. aureus (MRSA) mutant showed a greater acid tolerance response (ATR) to lactic and citric acids than the parent susceptible strain. These data indicates that methicillin resistance alters the morphology and ATR in stepwise-adapted MRSA mutant cells.