Optimization of culture conditions for antimetabolite production by a rare tea garden actinobacterial isolate, Amycolatopsis sp. ST-28

Background:Microbial metabolites are of great importance to the pharmaceutical industries. There is an urgent need of novel microbial metabolites in the present scenario to combat antimicrobial resistance. Selection and screening of potent microbial strains for production of antimicrobial metabolites as well as optimization of their culture conditions is of utmost importance in drug discovery. Therefore, the study was carried out to evaluate the effect of nutritional and cultural conditions on the production of bioactive metabolites by a rare tea garden actinobacterial strain Amycolatopsis sp. ST-28. Materials and methods:Submerged fermentation of the actinobacterial isolate was carried out on different culture media and different culture conditions such as carbon and nitrogen sources, inoculum volume, pH, fermentation period and agitation speed. The culture filtrate was assayed againstStaphylococcus aureus.Agar well diffusion method was employed to determine the maximum diameter of zone of inhibition (mm). The dried mycelial weight (mg) in a fixed volume of culture media was used for the determination of the total biomass produced.Results:Maximum bioactive metabolite and biomass production was observed when submerged fermentation was carried out with mannose and peptone respectively as a sole carbon and nitrogen source. Maintaining other environmental parameters viz. inoculum 11% (v/v), pH of 6.5, temperature of 32ºC and incubation period of 11 days at 150 rpm were found optimum for maximum antimicrobial activity. Conclusion:This study demonstrated optimized cultural conditions for improved production of antimicrobial compound by Amycolatopsis sp. ST-28

Optimization of cultural conditions affecting growth and improved bioactive metabolite production by a subsurface aspergillus strain TSF 146.

The aim of this study was to optimize cultural conditions for optimum growth and bioactive metabolite production by Aspergillus strain TSF 146, isolated from the subsurface soils of Brahmaputra plains, Assam, India. Agar disc diffusion assay was used to examine the antagonistic activity of the strain. The effect of different culture media, temperature, pH, incubation period, shaking, inoculum size and various carbon and nitrogen sources on the mycelial growth and bioactive metabolite production in a fixed volume of culture broth were studied. Aspergillus strain TSF 146 grew well and produced optimum bioactive metabolites in Potato dextrose broth medium at 25 °C on the 14th day of the incubation. The optimal mycelial growth, however, was obtained at pH 5.5. Sucrose (2.0 g/l) and asparagine (1.0 g/l) were the best carbon and nitrogen sources respectively for optimum growth and production of active metabolites by the isolate. Inoculum size of 2x1010 spores/ml with periodic shaking at 150 rpm optimized production of bioactive molecules. The results of the present investigation indicated that cultural conditions like carbon, nitrogen and mineral sources as well as physical factors such as temperature, pH, incubation period, inoculum size and shaking greatly affected the growth and production of bioactive metabolites by Aspergillus strain TSF 146.

Clinico-laboratory profile of haemolytic uremic syndrome.

OBJECTIVE: To study the clinical profile, the spectrum of functional abnormalities, prognostic factors and outcome of children with haemolytic uremic syndrome (HUS). MATERIALS AND METHODS: This is a prospective, descriptive, single centre, cohort study, conducted on 42 children during the period of January 2004 to January 2005. RESULTS: The maximum numbers of cases were below 24 months of age with mean age of 26.6 months and male: female ratio of 2.8:1. Most of the cases (79%) occurred in the warmer months (April-September). The common clinical presentations were bloody diarrhoea, pallor, oliguria & anuria, fever, vomiting, abdominal distension and pain, involvement of central nervous system, chest and cardiovascular system and bleeding manifestations. The common haematological abnormalities were leucocytosis, thrombocytopenia, anaemia and features of haemolysis in the peripheral blood. Electrolyte abnormalities observed were in the form of hyponatremia, hypokalemia and hyperkalemia. Arterial blood gas analysis showed metabolic acidosis in 64% cases, where the estimations were done. The mean blood urea and serum creatinine levels were 113.7 mg/dL and 2.5 mg/dL, respectively. Stool examination showed blood in all cases. Urine examination showed microscopic haematuria and significant proteinuria in 74% and 38% cases, respectively. E. coli and Shigella were isolated in stool in three cases each and one case showed mixed growth of E. coli and Salmonella. The mortality rate was 21%. Significantly higher mortality was observed in females, patients presenting with complete anuria, leucocytosis, hyperkalemia and systemic involvement like central nervous system, cardio vascular system and chest. CONCLUSIONS: Female sex, complete anuria, leucocytosis, extra renal involvement and hyperkalemia were associated with poor outcome.

Clinical and Bacteriological Profiles of Blood Culture Positive Sepsis in Newborns.

Neonatal infections currently cause about 1.6 million deaths annually in developing countries1. Sepsis and meningitis is responsible for most of these deaths. This study was undertaken to determine the clinical presentations, bacteriological profiles and antibiotic sensitivity patterns of isolates from blood cultures of neonates admitted in a tertiary care hospital in Eastern Nepal. All blood culture reports (n=103) during January 2006 - February 2007 from newborns admitted in neonatal division at BP Koirala Institute of Health Sciences, Nepal were analyzed and antibiotic sensitivity patterns were studied. The positive blood culture was 20% (103/513). Most (97.1%) of the sepsis was caused by single organism, while polymicrobial aetiology was observed in 2.9% cases. Meningitis was documented in 9(8.7%) cases. Staphylococcus aureus (38.8%) and coagulase negative staphylococcus (CONS) (21.3%) are the commonest isolates in blood culture. Among gram-negative organisms, Klebsiella species (11.6%) and Enterobacter species (9.7%) were the leading cause of neonatal sepsis. Majority of newborns with neonatal sepsis presented with refusal to feeds (42.7%), fever (41.7%) and jaundice (41.7%). Most of the organisms showed sensitivity with amino glycosides (gentamicin and amikacin) and third generation cephalosporins. It is concluded that Staphylococcus aureus, CONS, and Klebsiella species remain the principal organisms causing neonatal sepsis and first line antibiotics like amino glycosides should be first choice of drugs.

Wilson's disease in Eastern India.

INTRODUCTION: Wilson's disease is an inherited autosomal recessive (AR) disorder of copper metabolism transmitted by a mutant gene on chromosome 13q14-21 and results in abnormal accumulation of copper giving rise to protean manifestations. AIM: The aim is to study the clinical features, biochemical and radiological abnormalities of this disorder in Eastern India and the effect of treatment. RESULTS: Forty nine (n = 49) cases were studied over a period of 10 years. Majority of patients were male with mean age of onset being 11.13 years. They commonly presented with dysarthria, dystonia or drooling. The clinical features were dystonia (96%), silly smile (92%), dysarthria (80%), cognitive decline (71%), tremors (47%), bradykinesia (45%), etc. Family history suggested an autosomal recessive pattern. Sibling screening revealed that 4/8 (50%) were presymptomatic. All but one had presence of Keyser Fleischer (KF) ring in their cornea. Serum copper was reduced in 77% while ceruloplasmin was less in 94% of cases. The commonest abnormality seen in CT/MRI were in basal ganglia (74%) followed by white matter changes (59%) and brain stem changes (20.5%). The response to treatment was not as good and there was an initial deterioration in 50% of cases. Only five patients could go back to their school. CONCLUSION: Wilson's disease have protean manifestations. All children with slowly progressive extrapyramidal syndrome should be investigated for it. Screening of all asymptomatic siblings for Wilson's disease must be carried out. Early institution of proper treatment and life long continuation is indicated in all. In the present series, an earlier age of onset of neurological signs and symptoms were seen; there was initial deterioration in 50% of cases and the response to treatment was not as good.