ABSTRACT
@#Aims: To isolate and characterise actinomycetes from various sources of soil samples (fruit orchard, dipterocarp forest and oil palm plantation) and to screen these isolates forantibacterial activity against multi-drug resistant bacteria.Methodology and results: A total of 158 fast-growing actinomycete isolates with different colony morphologywere subjected to primary cross-streak and secondary well diffusion screening. Six isolates (OP1E, OP7A, OP2A-C, MG1A, UT9C1 and UT7E)were found to inhibit atleast one of the seven multi-drug resistant (MDR) bacteria. MG1A exhibited the strongest and broadest spectrum of antibacterial activity against 6 MDR bacteria tested. These isolates were identified as Streptomyces species based on 16S rRNA gene sequence analysis. Further morphological and biochemical analysis revealed that MG1A was highly similar to S. griseocarneus (98.36%)whereas OP1E and OP2A-C were similar to S. parvulus(99.93% and 99.51% respectively). Preliminary identification using LCMS/MS and database search revealed that the major compound in the extract of OP2A-C could be dactinomycin (1255.4170 g/mol). Other antibacterial compounds in the extracts remain to be identified. Conclusion, significance and impact of study: Soil actinomycetes with antibacterial activity against MDR bacteria were isolated not only from undisturbed natural soils but cultivated soils. These isolates were characterised, identified and the antibacterial compounds were extracted for further study. The isolates could serveas a potential source for the development of new and sustainable compounds against MDR bacteria.
ABSTRACT
<p><b>INTRODUCTION</b>Corneal infection is the most common cause of profound ocular morbidity leading to blindness worldwide. Corneal infection in children is difficult to diagnose and treat, as they are unwilling and sometimes unable to cooperate during active management. This study analyses the prevalence, microbiology, demography, therapeutic and visual outcome of infectious microbial keratitis in the paediatric age group seen at a tertiary eye care hospital in south India.</p><p><b>MATERIALS AND METHODS</b>A retrospective review of all cases presenting with keratitis to the ocular microbiology and cornea service at Aravind Eye Hospital, Coimbatore, from February 1997 to January 2004, was done to screen the patients for microbial keratitis. Their records were further analysed for clinical and microbiological details. Cases with culture-proven non-viral keratitis in children <or=15 years were included in the study. Full ophthalmic examination was performed for all cases.</p><p><b>RESULTS</b>Of the 310 patients who attended the cornea clinic, 97 (31.2%) patients were confirmed to be positive for microbial keratitis. 54.6% of cases were male. The most common predisposing cause of ulceration was trauma (69%) with organic matter. Pure bacterial cultures were obtained from 64 (65.9%) eyes, whereas pure fungal cultures were obtained from 37 (38.1%) eyes. Four (4.1%) eyes showed mixed growth.</p><p><b>CONCLUSION</b>The most commonly isolated organism was Pseudomonas aeruginosa. The most common predisposing cause of infectious microbial keratitis was corneal trauma. Early stage of diagnosis and formulation of an uncompromising management protocol can prevent profound visual morbidity.</p>