Antibiotic Resistance Prevalence and Pattern in Environmental Bacterial Isolates

Abstract

The present study investigates the prevalence of antibiotic resistance among bacterial isolates from different environmental samples and determines their resistance patterns. Bacteria were isolated from the Ganges water, the intestine of Labeo rohita, soil samples from agricultural land, and clinical samples of urine, pus, and throat swab. The bacterial isolates were identified on the basis of standard cultural, morphological and biochemical characteristics. Antibiotic susceptibility of the isolates was tested by disc diffusion and agar dilution method. A total of 87 bacteria belonging to 13 different genera were isolated. The percentages of resistance detected were, Ax: amoxycillin (82.75%), Te: tetracycline (49.42%), Tr: trimethoprim (41.37%), Ch: chloramphenicol (39.08%), Nx: nalidixic acid (22.98%), Ci: ciprofloxacin (24.13%), S: streptomycin (9.19%), G: gentamycin (4.59%) and Ak: amikacin (4.59%). A majority of 57 (65.51%) strains were multi-resistant; 77 (88.5%) were resistant to at least one drug. Determination of resistance pattern revealed that 3 water isolates and 1 clinical isolate belonging to Pseudomonas aeruginosa (n=3) and Proteus vulgaris (n=1) were resistant to all the 9 antibiotics tested; a Proteus mirabilis strain was resistant to all the drugs except G. In the seven-drug-resistant group, Klebsiella aerogenes showed AxChTeNxTSCi-resistance and P. mirabilis strain exhibited AxChTeNxTrGCi resistance pattern. The high prevalence of antibiotic-resistant bacteria harboring diverse resistance traits could represent a potential health risk. The study of antibiotic resistance helps predict future emergence and guide the development of strategies to counteract this resistance. Therefore periodic and comprehensive survey of antibiotic resistance in the environmental bacteria is required.