High prevalence and combinations of antimicrobial resistance traits in commensal bacteria from a very remote rural community of Alto Amazonas (Peru)

Abstract number: 10.1111/j.1198-743X.2004.902_o408.x

Mantella A.


Several aspects concerning the impact of antimicrobial usage in the emergence and spread of resistance remain poorly understood and are difficult to investigate due to the almost universal use of antimicrobial agents for several decades, and to the lack of representative bacterial collections from the preantibiotic era. The purpose of this work was to investigate antimicrobial susceptibility of the commensal Escherichia coli of the population of a very remote rural community of Peruvian Amazonas, where the use of antimicrobials has been minimal.


The studied community (113 subjects) was selected as one of the most isolate of the Alto Amazonas Province. Antimicrobial susceptibility of the commensal E. coli was investigated by means of a rapid screening method in which faecal swabs were plated onto McConkey Agar and antimicrobial disks (ampicillin-AMP, ceftriaxone-CRO, tetracycline-TE, chloramphenicol-C, trimethoprim-sulphamethoxazole-SXT, quinolones and aminoglycosides) were applied onto the seeded plate. Resistant isolates showing an E. coli-like colony morphology were collected, identified, and the susceptibility pattern was then confirmed by standard disk-diffusion method. A simple questionnaire was used to investigate antimicrobial usage (last 12 months) and to collect demographic information.


A total of 93 healthy subjects (42 males, 51 females; age range 0–59 years, median 9) was enrolled. Five of them (5%) reported previous antimicrobial use. Eighty-three of 93 (89%) subjects carried commensal E. coli resistant to at least one antimicrobial agent. The highest resistance rates were observed for TE (82%), AMP (68%), SXT (65%), and C (44%). The majority (85%) yielding antibiotic-resistant E. coli harboured multidrug–resistance (MDR) strains. The most frequent MDR phenotype included AMP, TE, and SXT. No resistance was detected against ceftriaxone, amikacin, nalidixic acid and ciprofloxacin.


The high resistance rates unexpectedly detected in this isolate community suggest that, in some cases, the spread and maintenance of resistant strains and resistance determinants could be not directly related to antimicrobial consumption. The notable diversity of resistance traits and of their combination patterns, underscore a considerable complexity of the resistant bacterial ecosystem and of their resistance-associated metagenome.

ANTRES project, supported by EU INCO-DEV grant (ICA4-CT-2001-10014).


Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
Back to top