Antimicrobial Resistance and Infection Control (Oct 2017)

Phenotypic and genotypic characteristics of ESBL and AmpC producing organisms associated with bacteraemia in Ho Chi Minh City, Vietnam

  • Nguyen Phu Huong Lan,
  • Nguyen Huu Hien,
  • Tu Le Thi Phuong,
  • Duy Pham Thanh,
  • Nga Tran Vu Thieu,
  • Dung Tran Thi Ngoc,
  • Ha Thanh Tuyen,
  • Phat Voong Vinh,
  • Matthew J. Ellington,
  • Guy E. Thwaites,
  • Nguyen Van Vinh Chau,
  • Stephen Baker,
  • Christine J. Boinett

DOI
https://doi.org/10.1186/s13756-017-0265-1
Journal volume & issue
Vol. 6, no. 1
pp. 1 – 9

Abstract

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Abstract Background Broad-spectrum antimicrobials are commonly used as empirical therapy for infections of presumed bacterial origin. Increasing resistance to these antimicrobial agents has prompted the need for alternative therapies and more effective surveillance. Better surveillance leads to more informed and improved delivery of therapeutic interventions, potentially leading to better treatment outcomes. Methods We screened 1017 Gram negative bacteria (excluding Pseudomonas spp. and Acinetobacter spp.) isolated between 2011 and 2013 from positive blood cultures for susceptibility against third generation cephalosporins, ESBL and/or AmpC production, and associated ESBL/AmpC genes, at the Hospital for Tropical Diseases in Ho Chi Minh City. Results Phenotypic screening found that 304/1017 (30%) organisms were resistance to third generation cephalosporins; 172/1017 (16.9%) of isolates exhibited ESBL activity, 6.2% (63/1017) had AmpC activity, and 0.5% (5/1017) had both ESBL and AmpC activity. E. coli and Aeromonas spp. were the most common organisms associated with ESBL and AmpC phenotypes, respectively. Nearly half of the AmpC producers harboured an ESBL gene. There was no significant difference (p > 0.05) between the antimicrobial resistance phenotypes of the organisms associated with community and hospital-acquired infections. Conclusion AmpC and ESBL producing organisms were commonly associated with bloodstream infections in this setting, with antimicrobial resistant organisms being equally distributed between infections originating from the community and healthcare settings. Aeromonas spp., which was associated with bloodstream infections in cirrhotic/hepatitis patients, were the most abundant AmpC producing organism. We conclude that empirical monotherapy with third generation cephalosporins may not be optimum in this setting.

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