Optimization of enhanced microbial production of zinc bacitracin by submerged fermentation technology.

Bacitracin is one of the most important antibiotics used in different biomedical fields. It helps to achieve sizeable amount of foreign exchange due to its use in the poultry feed. The cheap agricultural wastes are readily available for the preparation of fermentation media used for bacitracin production. The microorganisms could be mutated with different chemicals and UV radiation to improve bacitracin production. Thus, the current study was focused on the synthesis of low-cost and effective bacitracin by mutant strains of Bacillus licheniformis, employing the submerged fermentation technique. The bacteria were exposed to the UV irradiation for various time periods ranging from 5 to 40 min. These mutants were named as BLAA-5-BLAA-40. Mutant strain BLAA-25 produced maximum bacitracin, with significantly high activity (142.81 IU/mg) against Klebsiella pneumoniae but less activity against Escherichia coli (115.19 IU/mg). Several fermentation conditions were investigated to optimize bacitracin production. The highest bacitracin yield was obtained by an inoculum size of 10%, fermentation period 48 hr, pH 7, T = 37°C, using soybean meal as a substrate. Among all substrates, cucumber peel was the substrate showing the highest minimum inhibitory concentration (2.3 mg/ml and 2.7 mg/ml against K. pneumoniae and E. coli respectively). A comparison between commercial and experimentally produced Zn bacitracin showed that commercial bacitracin has a low activity (63.2 IU/mg) as compared with experimental bacitracin. Hence, the agro wastes and mutation could be used to increase the synthesis of Zn bacitracin in B. licheniformis.

Anomalous Origin of Left Anterior Descending Artery and Left Circumflex Artery from Right Coronary Sinus with Malignant Left Anterior Descending Artery Course: Role of Coronary CT Angiography Derived Fractional Flow Reserve in Decision Making.

Congenital coronary anomalies are uncommon and are mostly asymptomatic; however, patients may have symptoms depending on the origin and course of anomalous artery. Very rarely, coronary anomalies can also lead to life-threatening complications especially in young athletes. A malignant course of the left main (LM) or left anterior descending (LAD) artery between aorta and pulmonary artery is considered the most significant risk factor for such complications. Various noninvasive tests are available to evaluate myocardial ischemia due to anomalous coronary artery. Coronary computed tomography (CT) angiogram derived fractional flow reserve (CT-FFR) is a noninvasive diagnostic test which has shown promising results in the hemodynamic assessment of obstructive coronary artery disease. However, its role in coronary anomalies has not been studied. We present a case of a 22-year-old male who presented with atypical chest pain and was found to have anomalous origin of left anterior descending (LAD) artery and left circumflex (LCX) artery from right coronary sinus. LAD had a malignant course for which CT-FFR was done which was hemodynamically nonsignificant. The decision was made to manage the patient conservatively.