Production, purification and characterization of L-asparaginase from Streptomyces gulbargensis

L-asparaginase is an anti-neoplastic agent used in the lymphoblastic leukaemia chemotherapy. In the present study a novel strain, Streptomyces gulbargensis was explored for the production of extra-cellular L-asparaginase using groundnut cake extract. The optimum pH, temperature, inoculum size and agitation speed for enzyme production were pH 8.5, 40ºC, 1x10(8)spores/ml and 200 rev/min respectively. Maltose (0.5 percent) and L-asparagine (0.5 percent) proved to be the best carbon and nitrogen sources respectively. The enzyme was purified 82.12 fold and the apparent molecular weight of the enzyme was found to be 85 kDa. The optima pH and temperature for the enzyme were 9.0 and 40ºC respectively. The enzyme was more stable at the alkaline pH than at the acidic one and it retained 55 percent of the activity at 80ºC for 60 min.

Increasing prevalence of antibiotic resistance and multi drug resistance among uropathogens.

A study was conducted to examine the prevalence of antibiotic resistance in the strains of bacteria isolated from patients with suspected urinary tract infection. A total of 348 bacterial isolates were grown from semi quantitative urine culture and were of significant bacteriuria. The antibiotic susceptibility testing was performed on Muller-Hinton agar by disc diffusion method according to the standard criteria of the National Committee for Clinical Laboratory Standards, Antibiotic susceptibility testing revealed a high prevalence of resistance to ampicillin (55.4%) followed by nitrofurantoin (45.4%), gentamicin (45.1%), amikacin (41.4%) and co-trimoxazole (30.5%). E. coli and Klebsiella pneumonia showed 78.8 % and 75.3 % resistance to three or more drugs respectively. Cefotaxime (87.1%) appeared to be the most active antibiotic against the majority of isolates, followed by Norfloxacin (83.3%).

In vitro activity of norfloxacin against uropathogens and drug efficacy in simulated bladder model under diabetic conditions.

PURPOSE: The in vitro activity of norfloxacin was determined to maximize the correlation between susceptibility testing of the drug and the results of clinical therapy of urinary tract infection in diabetics. This study was carried out to observe the effect of changing concentration of norfloxacin on the growth of uropathogens under diabetic conditions. METHODS: The standard broth microdilution method was carried out to determine the minimum inhibitory concentration (MIC) using Mueller Hinton broth by varying pH of the medium (5.0, 5.5, 6.0, 6.5 and 7.0) and glucose concentration (100, 250, 500, 1000 and 2000 mg/dL). A specially designed mechanical bladder model system simulating hydrokinetic conditions that exist in the urinary tract of diabetics was employed. RESULTS: The loss of activity of norfloxacin was more pronounced (> four folds) at pH 5.0 and 2000 mg/dL sugar concentration. These findings were consistent with the experiment 'in vitro simulated bladder model' by exposing bacterial growth to varied norfloxacin and sugar concentration. CONCLUSIONS: Although norfloxacin is a drug of choice for non-diabetic and diabetic individuals with mild to moderate glucosuria, in severe diabetic individuals norfloxacin may not be an effective drug.