10.22376/ijpbs.2019.10.1.p1-12 Volume 2 Issue 2 2011 (April - June) Typhoid fever is a major health problem as the causative agent lessThan i greaterThan Salmonella enterica serovar typhi lessThan /i greaterThan and lessThan i greaterThan paratyphi A lessThan /i greaterThan has developed resistance to many antimicrobial agents. The study was undertaken to find out the antimicrobial susceptibility pattern of lessThan i greaterThan Salmonella lessThan /i greaterThan isolates. We have studied 176 lessThan i greaterThan Salmonella lessThan /i greaterThan isolates - 172 blood isolates, 3 stools isolates and one isolate from bone marrow. Antimicrobial susceptibility testing was done by disc diffusion method and MIC by agar dilution method. Out of 176 lessThan i greaterThan Salmonella lessThan /i greaterThan isolates, 133 were lessThan i greaterThan S. typhi lessThan /i greaterThan , 41 were lessThan i greaterThan S.paratyphi A lessThan /i greaterThan and 2 were lessThan i greaterThan S.typhimurium. lessThan /i greaterThan  98.5% of lessThan i greaterThan S.typhi lessThan /i greaterThan and 92.7% of lessThan i greaterThan S.paratyphi A lessThan /i greaterThan were resistant to nalidixic acid by MIC studies. 95.5% lessThan i greaterThan S.typhi lessThan /i greaterThan and 97.6% of lessThan i greaterThan S.paratyphi A lessThan /i greaterThan were found to have reduced susceptibility (0.125-0.5µg/ml) by MIC studies as reported earlier. As per CLSI standard MIC value of ≤ 1µg/ml is taken as sensitive, ≥ 4µg/ml is taken as resistance for lessThan i greaterThan Salmonella lessThan /i greaterThan isolates. Gopal Muthu,Arumugam Suresh,Gnadesikan Sumathy And Ramesh Srivani Antimicrobial susceptibility-Salmonella, Typhoid fever, Nalidixic acid, MIC values. 435-442