Muthu Gopal1, Sathishkumar Elumalai2, Suresh Arumugam3, Vishnuprabu Durairajpandian4, Munirajan Arasambattu Kannan5, Esthermary Selvam6, Srivani Seetharaman7. 1. Scientist-C, Model Rural Health Research Unit, National Institute of Epidemiology (ICMR), Primary Health Centre , Nadukallur, Tirunelveli, Tamil Nadu, India . 2. Research Scholar, Department of Microbiology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras , Taramani, Chennai, India . 3. Scientist-C, Centre for Drug Discovery and Development, Sathyabama University , Jeppiaar Nagar, Rajiv Gandhi Road, Chennai, India . 4. Scientist, National Hub for Healthcare Instrumentation Development, Centre for Biotechnology, Anna University , Chennai, India . 5. Professor, Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras , Taramani, Chennai, India . 6. Specialist Cum Head of Department of Microbiology, ESIC Hospital , K.K.Nagar, Chennai, Tamil Nadu, India . 7. Assistant Professor, Department of Microbiology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras , Taramani, Chennai, India .
Abstract
INTRODUCTION: Typhoid fever is endemic in India and other developing countries, causing major public health problems with high morbidity and mortality. The resistance of Salmonella enterica serovar Typhi (S. Typhi) towards commonly prescribed antimicrobials is increasing in developing countries. However, there have been several reports of the therapeutic failure of fluoroquinolones in patients with Salmonella infection. Resistance to quinolones/ fluoroquinolones commonly arises due to target site mutation. AIM: The present study was planned to analyze mutation in Quinolone Resistance Determining Region (QRDR) of quinolone resistant Salmonella isolates. MATERIALS AND METHODS: A total of 133 S. Typhi isolates (blood (n = 131), stool (n=1) and bone marrow aspirate (n=1)) from tertiary care hospitals in Chennai and Puducherry, were included in this study. Minimum Inhibitory Concentrations (MIC) were carried out according to the Clinical Laboratory Standard Institute (CLSI)guidelines 2014. Mutations in gyrA and parC genes were analyzed by PCR-RFLP (Restriction Fragment Length Polymorphism) method followed by DNA sequencing. RESULTS: Of the 133 S. Typhi, 99.2% were resistant to nalidixic acid and 21% were resistant to ciprofloxacin by MIC method. 94% of isolates showed Ser 83 mutation in gyrA and 21.8% of isolates showed Trp106-Gly mutation in parC. CONCLUSION: Mutations in gyrA and parC genes are highly prevalent among Salmonella species. Irrational use of fluoroquinolones may increase the accumulation of mutations in the DNA gyrase and topoisomerase encoding genes, which lead to the emergence of high level fluoroquinolone-resistant Salmonella strains in future.
INTRODUCTION:Typhoid fever is endemic in India and other developing countries, causing major public health problems with high morbidity and mortality. The resistance of Salmonella enterica serovar Typhi (S. Typhi) towards commonly prescribed antimicrobials is increasing in developing countries. However, there have been several reports of the therapeutic failure of fluoroquinolones in patients with Salmonella infection. Resistance to quinolones/ fluoroquinolones commonly arises due to target site mutation. AIM: The present study was planned to analyze mutation in Quinolone Resistance Determining Region (QRDR) of quinolone resistant Salmonella isolates. MATERIALS AND METHODS: A total of 133 S. Typhi isolates (blood (n = 131), stool (n=1) and bone marrow aspirate (n=1)) from tertiary care hospitals in Chennai and Puducherry, were included in this study. Minimum Inhibitory Concentrations (MIC) were carried out according to the Clinical Laboratory Standard Institute (CLSI)guidelines 2014. Mutations in gyrA and parC genes were analyzed by PCR-RFLP (Restriction Fragment Length Polymorphism) method followed by DNA sequencing. RESULTS: Of the 133 S. Typhi, 99.2% were resistant to nalidixic acid and 21% were resistant to ciprofloxacin by MIC method. 94% of isolates showed Ser 83 mutation in gyrA and 21.8% of isolates showed Trp106-Gly mutation in parC. CONCLUSION: Mutations in gyrA and parC genes are highly prevalent among Salmonella species. Irrational use of fluoroquinolones may increase the accumulation of mutations in the DNA gyrase and topoisomerase encoding genes, which lead to the emergence of high level fluoroquinolone-resistant Salmonella strains in future.
Authors: J Wain; N T Hoa; N T Chinh; H Vinh; M J Everett; T S Diep; N P Day; T Solomon; N J White; L J Piddock; C M Parry Journal: Clin Infect Dis Date: 1997-12 Impact factor: 9.079