title: Quinolone resistance in absence of selective pressure: the experience of a very remote community in the Amazon forest.
abstract: BACKGROUND
  Quinolones are potent broad-spectrum bactericidal agents increasingly employed also in resource-limited countries. Resistance to quinolones is an increasing problem, known to be strongly associated with quinolone exposure. We report on the emergence of quinolone resistance in a very remote community in the Amazon forest, where quinolones have never been used and quinolone resistance was absent in 2002.
  
  
  METHODS
  The community exhibited a considerable level of geographical isolation, limited contact with the exterior and minimal antibiotic use (not including quinolones). In December 2009, fecal carriage of antibiotic resistant Escherichia coli was investigated in 120 of the 140 inhabitants, and in 48 animals reared in the community. All fluoroquinolone-resistant isolates were genotyped and characterized for the mechanisms of plasmid- and chromosomal-mediated quinolone resistance.
  
  
  RESULTS
  Despite the characteristics of the community remained substantially unchanged during the period 2002-2009, carriage of quinolone-resistant E. coli was found to be common in 2009 both in humans (45% nalidixic acid, 14% ciprofloxacin) and animals (54% nalidixic acid, 23% ciprofloxacin). Ciprofloxacin-resistant isolates of human and animal origin showed multidrug resistance phenotypes, a high level of genetic heterogeneity, and a combination of GyrA (Ser83Leu and Asp87Asn) and ParC (Ser80Ile) substitutions commonly observed in fluoroquinolone-resistant clinical isolates of E. coli.
  
  
  CONCLUSIONS
  Remoteness and absence of antibiotic selective pressure did not protect the community from the remarkable emergence of quinolone resistance in E. coli. Introduction of the resistant strains from antibiotic-exposed settings is the most likely source, while persistence and dissemination in the absence of quinolone exposure is likely mostly related with poor sanitation. Interventions aimed at reducing the spreading of resistant isolates (by improving sanitation and water/food safety) are urgently needed to preserve the efficacy of quinolones in resource-limited countries, as control strategies based only on antibiotic restriction policies are unlikely to succeed in those settings.
authors.affiliation: Dipartimento di Biotecnologie, Sezione di Microbiologia, Università di Siena, Siena, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Pallecchi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bartoloni
authors.forename: Eleonora
authors.initials: E
authors.lastname: Riccobono
authors.forename: Connie
authors.initials: C
authors.lastname: Fernandez
authors.forename: Antonia
authors.initials: A
authors.lastname: Mantella
authors.forename: Donata
authors.initials: D
authors.lastname: Magnelli
authors.forename: Dario
authors.initials: D
authors.lastname: Mannini
authors.forename: Marianne
authors.initials: M
authors.lastname: Strohmeyer
authors.forename: Filippo
authors.initials: F
authors.lastname: Bartalesi
authors.forename: Hugo
authors.initials: H
authors.lastname: Rodriguez
authors.forename: Eduardo
authors.initials: E
authors.lastname: Gotuzzo
authors.forename: Gian Maria
authors.initials: GM
authors.lastname: Rossolini
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002353:Carrier State / Q000382:microbiology* / Q000662:veterinary*; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010957:Plasmids / Q000032:analysis; D015363:Quinolones / Q000494:pharmacology*; D012424:Rural Population; D013020:South America; D014197:Trees; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones