Influence of Urine on Antimicrobial Gradient and Disk Diffusion Susceptibility Testing of Co-trimoxazole, Fosfomycin, Norfloxacin and Nitrofurantoin against Urinary Escherichia coli
Anju Kuriakose
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
Arathy Krishna
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
Gopika Raj R G
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
Sruthi P
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
Divya Das
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
Anila Gopal
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
Innu S
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
Roopa Mathews
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
Harish Kumar K S *
Department of Medical Microbiology, School of Medical Education, Center for Professional and Advanced studies, Kottayam, Kerala, India.
*Author to whom correspondence should be addressed.
Abstract
Aim: The aim of present study is to examine the influence of urine on zone of inhibition and Minimum inhibitory concentration by antimicrobial gradient strips of Co-trimoxazole, Fosfomycin, Norfloxacin and Nitrofurantoin against urinary E. coli.
Study Design: Cross- sectional study.
Place and Duration of Study: Department of Medical Microbiology, School of Medical Education, Kottayam, Kerala, India. Between January 2023 and November 2023.
Methodology: A total of 75 E. coli isolates collected from various diagnostic microbiology laboratories were included in the study. Identification of isolates and antimicrobial susceptibility testing was done. Direct v/s standard zone of inhibition and MIC was determined. The data was statistically analysed using Cohen’s kappa for interrater reliability and Intraclass correlation coefficient for consistency level.
Results: Current study evaluated the effect of urine on zone of inhibition and MIC by disc diffusion and antibiotic gradient testing respectively. The kappa value, a measure of agreement between direct v/s standard zone of inhibition and MIC for Co-trimoxazole, Fosfomycin, Norfloxacin was a perfect 1 (P=.000), indicating complete agreement. While, The kappa value, a measure of agreement between direct and standard MIC determination for Nitrofurantoin, was .67 (P=.000), indicating substantial agreement.
Conclusion: The present study suggest that direct antimicrobial susceptibility testing can be employed for Co-trimoxazole, Fosfomycin, Norfloxacin and Nitrofurantoin which are important drugs in the management of UTI, after further standardization.
Keywords: Escherichia coli, co-trimoxazole, fosfomycin, norfloxacin, nitrofurantoin, direct sensitivity testing, antimicrobial susceptibility testing, urinary tract infection