Antimicrobial resistance among blood culture isolates of Salmonella enterica in New Delhi.

INTRODUCTION Enteric fever is a global public health problem, especially in developing countries. Antimicrobial resistance is a major issue enteric fever management. This study examined current pattern of antimicrobial susceptibility among Salmonella enterica isolates from enteric fever cases at a tertiary care centre in New Delhi, India. METHODOLOGY Blood cultures from patients with enteric fever during January 2010- July 2012 were processed using the BACTEC automated system. Antimicrobial susceptibility was tested using Kirby Bauer's disc diffusion method and/or Phoenix 100 automated system. RESULTS Of 344 isolates of Salmonella enterica, 266 (77.3%) were S. Typhi, 77 (22.4%) were S. Paratyphi A, and one (0.3%) was S. Paratyphi B. Resistance to nalidixic acid (NA(R)) (96.7%) was most common, followed by ciprofloxacin (37.9%), and azithromycin (7.3%). Multi-drug resistance was observed only in S. Typhi (3.4%). Among NA(R) strains, 61.8% were sensitive, 11.1% were moderately sensitive, and 23.9% were resistant to ciprofloxacin (0.8%, 57.4%, and 37.9% respectively according to revised CLSI breakpoint criteria for ciprofloxacin). Resistance to third-generation cephalosporin was found in seven (2%) strains of S. enterica. CONCLUSION Increasing rates of nalidixic acid, fluoroquinolone and azithromycin resistance among S. enterica, particularly in S. Paratyphi A strains, is of concern, as S. Paratyphi A infection is becoming increasingly common and is not prevented by current vaccinations. Our results favour use of cefexime or possibly chloramphenicol as first choice for uncomplicated enteric fever. MICs for third-generation cephalosporins and susceptibility pattern must be closely monitored in view of its emerging resistance among Salmonella enterica.

[1]  G. Menezes,et al.  Antimicrobial resistance trends in blood culture positive Salmonella Typhi isolates from Pondicherry, India, 2005-2009. , 2012, Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases.

[2]  F. Abdullah,et al.  Enteric fever in Karachi: current antibiotic susceptibility of Salmonellae isolates. , 2012, Journal of the College of Physicians and Surgeons--Pakistan : JCPSP.

[3]  J. Crump,et al.  Antimicrobial Susceptibility to Azithromycin among Salmonella enterica Isolates from the United States , 2011, Antimicrobial Agents and Chemotherapy.

[4]  J. Farrar,et al.  Gatifloxacin versus chloramphenicol for uncomplicated enteric fever: an open-label, randomised, controlled trial , 2011, The Lancet. Infectious diseases.

[5]  G. Menezes,et al.  ACC-1 β-Lactamase–producing Salmonella enterica Serovar Typhi, India , 2010, Emerging infectious diseases.

[6]  Kavita Nagshetty,et al.  Antimicrobial susceptibility of Salmonella Typhi in India. , 2010, Journal of infection in developing countries.

[7]  A. Zaidi,et al.  Antibiotic resistance among Salmonella enterica serovars Typhi and Paratyphi A in Pakistan (2001-2006). , 2008, Journal of infection in developing countries.

[8]  S. Parija,et al.  A case report and review of the literature: ciprofloxacin resistant Salmonella enterica serovar Typhi in India. , 2008, Journal of infection in developing countries.

[9]  P. Savelkoul,et al.  Extended-Spectrum-Beta-Lactamase Production in a Salmonella enterica Serotype Typhi Strain from the Philippines , 2008, Journal of Clinical Microbiology.

[10]  Tikki Pang,et al.  A study of typhoid fever in five Asian countries: disease burden and implications for controls. , 2008, Bulletin of the World Health Organization.

[11]  M. Capoor,et al.  In vitro activity of azithromycin, newer quinolones and cephalosporins in ciprofloxacin-resistant Salmonella causing enteric fever. , 2007, Journal of medical microbiology.

[12]  S. Amarnath,et al.  Fluoroquinolone resistance in Salmonella typhi and S. paratyphi A in Bangalore, India. , 2007, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[13]  J. Wain,et al.  Randomized Controlled Comparison of Ofloxacin, Azithromycin, and an Ofloxacin-Azithromycin Combination for Treatment of Multidrug-Resistant and Nalidixic Acid-Resistant Typhoid Fever , 2006, Antimicrobial Agents and Chemotherapy.

[14]  S. Rubino,et al.  Molecular characterization of ciprofloxacin-resistant Salmonella enterica serovar Typhi and Paratyphi A causing enteric fever in India. , 2006, The Journal of antimicrobial chemotherapy.

[15]  V. Sharma,et al.  Treatment of enteric fever in children on the basis of current trends of antimicrobial susceptibility of Salmonella enterica serovar typhi and paratyphi A. , 2006, Indian journal of medical microbiology.

[16]  R. Gaind,et al.  Current perspectives of enteric fever: a hospital-based study from India , 2005, Annals of tropical paediatrics.

[17]  S. Kabra,et al.  Reduced susceptibility to ciprofloxacin and gyra gene mutation in North Indian strains of Salmonella enterica serotype Typhi and serotype Paratyphi A. , 2004, Microbial drug resistance.

[18]  S. Parija,et al.  Isolated high-level ciprofloxacin resistance in Salmonella enterica subsp. enterica serotype Paratyphi A. , 2004, Journal of medical microbiology.

[19]  C. Parry.  The treatment of multidrug-resistant and nalidixic acid-resistant typhoid fever in Viet Nam. , 2004, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[20]  J. V. van Dissel,et al.  Risk factors for typhoid and paratyphoid fever in Jakarta, Indonesia. , 2004, JAMA.

[21]  J. Wain,et al.  The emergence of antibiotic resistance in typhoid fever. , 2004, Travel medicine and infectious disease.

[22]  J. Crump,et al.  The global burden of typhoid fever. , 2004, Bulletin of the World Health Organization.

[23]  T. Butler,et al.  In vitro effects of azithromycin on Salmonella typhi: early inhibition by concentrations less than the MIC and reduction of MIC by alkaline pH and small inocula. , 2001, The Journal of antimicrobial chemotherapy.

[24]  T. Butler,et al.  Azithromycin versus ceftriaxone for the treatment of uncomplicated typhoid fever in children. , 2000, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[25]  R. Tauxe,et al.  Laboratory-based surveillance of Salmonella serotype Typhi infections in the United States: antimicrobial resistance on the rise. , 2000, JAMA.

[26]  T. Butler,et al.  Treatment of typhoid fever with azithromycin versus chloramphenicol in a randomized multicentre trial in India. , 1999, The Journal of antimicrobial chemotherapy.

[27]  A. Kapil,et al.  Paratyphoid fever in India: An emerging problem. , 1999, Emerging infectious diseases.

[28]  S. Saha,et al.  A highly ceftriaxone-resistant Salmonella typhi in Bangladesh. , 1999, The Pediatric infectious disease journal.

[29]  S. Rai,et al.  Rationale of azithromycin prescribing practices for enteric fever in India. , 2012, Indian journal of medical microbiology.

[30]  J. Chander,et al.  An increase in enteric fever cases due to Salmonella Paratyphi A in & around Chandigarh. , 2009, The Indian journal of medical research.

[31]  C. Wattal,et al.  High level ciprofloxacin resistance in Salmonella enterica isolated from blood. , 2008, Indian journal of medical microbiology.

[32]  B. Metchock.  In-vitro activity of azithromycin compared with other macrolides and oral antibiotics against Salmonella typhi. , 1990, The Journal of antimicrobial chemotherapy.

[33]  S. Saxena,et al.  Salmonella paratyphi A infection in India: incidence and phage types. , 1966, Transactions of the Royal Society of Tropical Medicine and Hygiene.