In vitro susceptibility pattern of Sporothrix schenckii strains isolated from three centers in India.

BACKGROUND & OBJECTIVES: With the availability of more number of antifungal agents in recent years, drugs other than saturated solution of potassium iodide (SSKI) are being increasingly used to treat sporotrichosis. It was therefore considered pertinent to evaluate in vitro antifungal susceptibility pattern of Sporothrix schenckii strains isolated at three centers in India against five commonly used antifungal agents. METHODS: Agar dilution method was used to evaluate 50 clinical isolates (25 from north, 17 from east and 8 from south India) both in its yeast and mycelial forms against amphotericin-B, 5-fluorocytosine, ketoconazole, fluconazole and itraconazole. RESULTS: No resistance was observed in the yeast form of S. schenckii against amphotericin B and azoles. However, 54 per cent strains in the yeast form were resistant to 5-fluorocytosine. None of the strains was susceptible to amphotericin B and ketoconazole, 56 and 10 per cent strains in the mycelial form were susceptible to itraconazole and fluconazole respectively. No significant difference was observed in the antifungal susceptibility pattern among the strains isolated from these three regions in India. INTERPRETATION & CONCLUSION: Clinical isolates of S. schenckii from three regions of India had a more or less uniform antifungal susceptibility pattern. Itraconazole had the best in vitro susceptibility results against the clinical isolates of S. schenckii and has the potential to replace SSKI.

Clinical profile of pulmonary nocardiosis.

Pulmonary nocardiosis mimics pulmonary tuberculosis in both clinical symptoms, being chronic in nature and radiological characteristics, and it is often wrongly treated with anti-tuberculosis drugs. The present study was undertaken to determine the prevalence of pulmonary nocardial infection in patients having chronic chest symptoms and to study their clinical response to specific chemotherapeutic agents. All the patients, who had a negative sputum for AFB on direct smear examination consecutively, were investigated for nocardiosis by examining the sputum with KOH preparation and modified Ziehl-Neelsen method. This was later confirmed by fungal culture of the sputum and inoculation on McClung's broth for paraffin baiting technique. Fibreoptic bronchoscopy was performed on all the suspected cases and the bronchial aspirate was examined similarly. The confirmed cases of nocardiosis were treated with cotrimaxazole and doxycycline for a total duration of six months. The prevalence of pulmonary nocardiosis in the present study was 1.9 percent. All the patients were immunocompetent. All the patients showed a good clinical response to chemotherapy at the end of six months of treatment. No relapse has been observed on follow up.

Antimicrobial susceptibility of Salmonella typhi to quinolones & cephalosporins.

Antimicrobial sensitivity testing was carried out for 85 isolates of S. typhi by disc diffusion and microbroth dilution for estimation of minimum inhibitory concentration (MIC). The drugs used included amoxycillin, chloramphenicol, ciprofloxacin, ofloxacin, gentamicin, netilmicin, cefuroxime, ceftizoxime, cefoperazone and ceftazidime. Ninety three per cent of our isolates were resistant to amoxycillin and chloramphenicol but total susceptibility was seen to quinolones and aminoglycosides. We also found that 3 per cent of our isolates were resistant to cephalosporins and 23 per cent were in the intermediate range with an MIC of 12.5 or 25 micrograms/ml to these drugs. In spite of decreased efficacy, the strains continued to be fully susceptible to ciprofloxacin as could be seen from the extended dilutions in microbroth dilution tests. The study also revealed that there was lack of correlation between the two methods of sensitivity testing for cephalosporins. We feel that the development of resistance of S. typhi to third generation cephalosporins is a finding worth consideration for further studies.