rates of antibacterial exposure were calculated as the ratio of the number of treatments prescribed divided by the number of villagers and compared by using analysis of variance . chi - square - tests or fisher exact tests were used for binary variables . during the year preceding the study , 24 ( 6.1% ) of 388 villagers had been hospitalized ; 235 ( 60.6% ) had received no treatment with antibacterial agents . one hundred fifty - three ( 39.4% ) of the villagers had received 250 courses of antibacterial treatments . of the therapeutic agents used , 72 ( 28.8% ) were aminopenicillins , 111 ( 44.4% ) were metronidazole , 36 ( 14.4% ) were macrolides , and 31 ( 12.4% ) were different antibacterial agents ( 17 penicillin m , 2 penicillin g , 7 cotrimoxazole , 3 cyclines , and 2 first - generation cephalosporins ) . ninety - eight ( 25.3% ) villagers had received one couse of treatment , 30 ( 7.7% ) received 2 couses of treatments , 13 ( 3.4% ) received 3 courses of treatments , and 12 ( 2.1% ) received > 4 courses of treatments . overall antibacterial and aminopenicillin exposures were significantly higher in village z , where the paramedical officer resided ( table 1 ) , and in children . frequency of antibacterial exposure was calculated by dividing the number of all antibacterial courses during the year preceding the study by the number of persons in each village . analysis of variance ( anova ) . in october 1999 , one of the investigators ( v.j . or a.a . ) asked each adult to participate in the study . exclusion criteria were fever , diarrhea , or acute infection , and a stay outside the study zone , a history of hospitalization ( verified by cayenne s hospital records ) , or treatment with an antibacterial agent ( verified by records of the paramedical officer ) during the preceding year . we chose this period for surveillance because it was the longest period for which information was available . the study was approved by the comit consultatif de protection des personnes se prtant  des recherches biomdicales ( ccpprb ) of cayenne and by the administrative authorities of french guyana and was authorized by the french ministry of health . before participants were included , the study was presented to the villagers , with the aid of the chief of the village who explained that some of them would be asked to participate . study participants were asked to bring fresh stool samples ( unformed samples were excluded ) to the paramedic officers . the samples were then mixed into brain - heart infusion broth with 10% glycerol and frozen in liquid nitrogen . upon harvesting , 25 l of broth was added to 2 ml of brain - heart infusion broth , incubated for 4 h , and plated on cetrimide , chapman , and bile - esculin - acid agar containing 10 mg / l of vancomycin ( after an enrichment step of 18 h in broth containing 1 mg / l of vancomycin ) to detect pseudomonas aeruginosa , staphylococcus aureus , and vancomycin - resistant enterococci , respectively . drigalski agar plates were plated with the fecal dilutions ; after 48 h growth , five colonies were randomly selected , identified , and tested for antibacterial susceptibility as described ( http://www.sfm.asso.fr ) . a participant was defined as colonized in the predominant flora with gram - negative bacteria resistant to a given antibacterial agent when at least one strain resistant to this antibacterial agent was isolated . drigalski agar plates were supplemented with either ampicillin ( 10 mg / l ) , ceftazidime ( 2 mg / l ) , streptomycin ( 20 mg / l ) , kanamycin ( 20 mg / l ) , chloramphenicol ( 20 mg / l ) , tetracycline ( 10 mg / l ) , or nalidixic acid ( 50 mg / l ) ( 3 ) , used within 24 h after preparation , and kept at 4c until used . the plates were plated with the fecal dilutions , incubated for 48 h , and inspected for lactose - positive and lactose - negative colonies . a participant was defined as colonized in the subdominant flora with gram - negative bacteria resistant to a given antibacterial agent when at least one colony grew on agar containing the corresponding antibacterial agent . no further identification was performed ; for quality control purposes , some positive plates were randomly selected for confirmation of antibacterial susceptibility of the isolates . because the number were few and unexpected , colonies that grew on agar containing ceftazidime were all identified by conventional methods or 16s rna gene sequencing ( 4 ) , when needed ; their antibacterial susceptibility was tested ; and genes encoding for extended spectrum -lactamase were characterized , when needed , by polymerase chain reaction and sequencing ( 5 ) . when needed , the clonality of isolates was determined by using pulsed - field gel electrophoresis ( pfge ) ( 6 ) . the fecal flora was thus analyzed in a subgroup of 93 volunteers ( 39 men and 54 women ; 41.2% from village ts , 18.1% from village z , and 23.6% village yp [ p < 0.001 ] ) who met the inclusion criteria cited above , representing 93 ( 23.9% ) of 388 villagers and 93 ( 39.6% ) of 235 who had not received antibacterial agents for 1 year . carriage of resistant gram - negative bacteria in subdominant flora of these 93 volunteers ranged from > 90% for those resistant to ampicillin , streptomycin , and tetracycline to 7% for those resistant to nalidixic acid ( table 2 ) , with no significant difference for sex or age . we found no association between the rate of resistance in the study participants and the number persons who used antibacterial agents or of children in the hut . fourteen participants ( all living in village z but not in the same hut ) were colonized by gram - negative bacteria resistant to ceftazidime , including three escherichia coli strains with a similar pattern by pfge that produced blatem-52 extended spectrum -lactamase . nine participants ( three , one , and five living in villages ts , yp and z , respectively , and only two in the same hut ) were colonized by strains of acinetobacter baumannii sharing the same susceptibility pattern . two participants ( one in village ts and one in village z ) were colonized by strains of ochrobactrum spp . one participant from village z was colonized by a vancomycin - resistant strain of enterococcus gallinarum . accounting for 23.9% ( 93 of 388 ) of the global population of the villages studied and not significantly different from it for male / female ratio or age distribution . bacteria with intermediate susceptibility were categorized as resistant .  extended spectrum -lactamase e. coli . acinetobacter baumanni : 9 ( all with the same susceptibility pattern including susceptibility to ureidopenicillins , third - generation cephalosporins , aminoglycosides , and quinolones ) and ochrobactrum spp . resistance rates in the predominant flora were from 95% to tetracycline to 0% to ceftazidime and nalidixic acid , with no significant differences between adults and children , men and women , or villages . although they were not chosen randomly , approximately 40% of the untreated villagers were included , which suggests that the group was representative of the whole community . recently , high resistance rates were also reported in remote populations from bolivia ( 7 ) and nepal ( 2 ) . here , however , we have provided additional information on exposure to antibacterial drugs and hospitalizations of the study participants . in the villages studied , the global antibacterial exposure ( 0.64 treatments / person / year ) was roughly half that of france ( 8) , thus close to the mean rate of european union countries ( 9 ) , which stresses the indirect impact of antibacterial use on persons who do not use them . unrecorded antibacterial drug use in the participants was unlikely because no alternate sources of antibacterial agents existed , and free antibacterial agents were provided when needed , decreasing the likelihood of nonprescribed use or sharing of antibacterial agents by family members . our results can be compared only to those of studies performed with similar methods and in persons who also had not taken antibacterial drugs . for instance , resistance rates of predominant e. coli in the wayampis population to ampicillin , tetracycline , and streptomycin were higher than that observed in french bank workers ( 10 ) or bostonian children ( 1 ) , but close to that reported in children from venezuela and china ( 1 ) . that the resistance rate was higher in the wayampis amerindians than in the french workers was unexpected , considering the higher levels of antibacterial drug use in the french community . these data suggested frequent cross - transmission likely attributable to poor hygiene ( 1,2 ) . cross - transmission is common among households , even in industrialized countries ( 11 ) . its role in the spread of drug - resistant bacteria among the wayampis amerindians , even in adults , was further indicated by the lack of difference in resistance rates according to age . resistance to quinolones , which were not used in this community , was lower than in europe ( 12 ) , which illustrates the specificity of selective pressure . thus , how samples from three participants were colonized by an e. coli  carrying blatem-52 ( 13 ) , an extended - spectrum -lactamase - gene found only in hospitals , is difficult to explain . enterobacteria that produced an extended spectrum -lactamase were prevalent at the time in the cayenne hospital ( b.m . , unpub . data ) . since the three persons with the blatem-52 -colonized samples had not been hospitalized during the previous year , possibly this strain , or a different one , carrying blatem-52 was acquired and spread in the community by one of the 24 villagers hospitalized during the year preceding the study . if they were hospitalized and colonized during hospitalization , this colonization would not have been likely to have persisted for so long ; indeed , carriage of resistant nasal staphylococci can last for months , but resistance in intestinal enterobacteria decreases within 1020 days after selective pressure ends ( 15 ) . antibacterial agents in the food chain are a source of resistance in industrialized countries ( 16 ) . in our study , food was strictly local but may have been the source of the wild - type naturally resistant a. baumannii and ochrobactrum spp . environmental species have also been isolated in amerindians living in nearby ( formerly dutch ) guyana ( 17 ) . because data confirmed the lack of direct antibacterial drug exposure in our study participants , the results demonstrate that , once resistance elements are introduced into a population , moderate use of antibacterial drugs in the environment is enough to maintain them in intestinal bacteria when sanitary conditions are poor .
drug resistance in fecal bacteria was high in wayampis amerindians who did not take antibacterial agents and were not hospitalized for 1 year . in the wayampis amerindians , 
 an isolated traditional community in french guyana , antibacterial use was 0.64 treatments per person per year . 
 hospitalization rate was 6.1% per year . 
 antibacterial drug  resistant bacteria can spread in persons who are not taking antibacterial agents .