Resistance among fecal flora of patients taking sulfamethoxazole-trimethoprim or trimethoprim alone

In a previous study, we found fecal colonization with multiresistant Escherichia coUl exhibiting high-level trimethoprim resistance in 19% of diapered children attending six day-care centers in Houston, Tex. To examine the potential risk factors associated with this finding, we conducted cross-sectional studies among 203 children attending 12 day-care centers, 51 children attending a well-child clinic (controls), and 64 medical students. The prevalence of fecal colonization with trimethoprim-resistant E. coli among children attending day-care centers (30%) was higher (P < 0.001) than among control children (6%) or medical students (8%). The prevalence of colonization among the children attending the 12 centers ranged from 0 to 59% and was correlated with the number of diapered children enrolled (r = 0.73; P < 0.01). In a case control study among the day-care center children, significant risk factors were an age of less than 12 months and attendance at a center with an enrollment of over 40 diapered children (odds ratios of 2.2 and 3.5, respectively); ethnicity, duration of attendance, and prior antibiotic administration were not associated with colonization. Plasmid analysis of 60 of the day-care center strains revealed 22 profiles, each of which was unique to a given day-care center. Transmission and carriage of trimethoprim-resistant strains for as long as 6 months was documented in one center studied on three occasions. Given the documented transmission of enteric pathogens among diapered children attending day-care centers and their spread into family members, it is likely that day-care centers are an important community reservoir of plasmid-associated antibiotic-resistant E. coli.Resistance to antimicrobial agents, an increasing problem worldwide, is particularly common in certain settings, including tertiary care hospitals, animal feedlots, and developing countries (10). In a study conducted in 1983, trimethoprim resistance (Tmp) was found in 40 to 50% of over 2,500 human clinical isolates of Escherichia coli in Chile and Thailand but in only 4 to 8% of concurrent clinical isolates of E. coli in the United States (11). Since most E. coli infections result from endogenous fecal E. coli, one might hypothesize that the frequency of Tmpr among fecal E. coli would parallel that among clinical isolates in the same population. Levy et al. (7) found 7.5% of healthy medical students in Boston in 1987 to be colonized with Tmpt E. coli, a frequency similar to that among U.S. clinical E. coli isolates (11).We conducted a pilot study of antimicrobial agent-resistant fecal flora among children attending day-care centers (DCC) in Houston, Tex., in 1986 (17) and reported that 19% of 79 diapered children in seven DCC were colonized with Tmpr E. coli, all of which were multiresistant. This frequency of Tmpr was higher than that previously reported among strains colonizing healthy U.S. adults (7) or adults receiving trimethoprim (TMP) (3,14,19,20) Moreover, the overall Tmpr E. coli colonization rate of 19% was due primarily...

contrasting

confidence: 50%

contrasting

confidence: 48%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Risk factors for fecal colonization with trimethoprim-resistant and multiresistant Escherichia coli among children in day-care centers in Houston, Texas

Reves¹,

Fong²,

Pickering³

et al. 1990

“…Fecal specimens were obtained from the participants before departure (week 0); during weeks 1, 2, 3, and 6 (15,21). Representative E. coli-like colonies growing on PW with TMP were also inoculated into peptone stabs and transported to Houston.…”

Section: Methodsmentioning

confidence: 99%

Emergence of resistant fecal Escherichia coli in travelers not taking prophylactic antimicrobial agents

Murray

Mathewson

DuPont

et al. 1990

Fecal specimens from individuals traveling to Mexico were examined before, during, and after travel for the presence of Escherichia coli resistant to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, sulfonamides, trimethoprim (TMP), and TMP-sulfamethoxazole (TMP-SMX). None of these individuals took prophylactic antibiotics, although 4 of 13 took short courses of an antimicrobial agent for therapy of traveler's diarrhea. With an average of 9.3 E. coli per sample, resistance to all agents tested except gentamicin was shown to increase during the time in Mexico (P < 0.001 to P < 0.05). For example, no TMP-resistant (Tmpr) E. coli isolates were found by this method before travel, whereas 57% of the individuals had Tmpr and Tmpr_Smxr E. coli by the final week in Mexico. This increase in resistance occurred regardless of whether an individual took a short course of antimicrobial therapy. This study shows that travel itself, even without the use of prophylactic or therapeutic antimicrobial agents, is associated with the acquisition of resistant E. coli. Travel to developing nations may rival other sources of resistant organisms.A number of studies have established that travel to developing countries is associated with an increased risk of diarrheal illness, presumably caused by ingestion of enteric pathogens (7,19). We have also shown that travelers to Mexico who consumed prophylactic trimethoprim (TMP) or TMP-sulfamethoxazole (TMP-SMX), but not placebo, for three weeks while in Mexico had their TMP-susceptible fecal Escherichia coli replaced by TMP-resistant E. coli; since this was not observed in a similar study in the United States, the emergence of resistance in travelers to Mexico was felt to be related to increased exposure to resistant organisms as well as to the selective pressure exerted by the antibiotics (12). We have now studied fecal E. coli from travelers to Mexico who were not taking prophylactic antibiotics; the goal was to determine if travel to a developing region, even without antibiotic therapy, is associated with the emergence of antibiotic-resistant fecal E. coli. MATERIALS AND METHODSStudy participants included 13 residents of the United States traveling to Guadalajara, Mexico, in 1987. Fecal specimens were obtained from the participants before departure (week 0); during weeks 1, 2, 3, and 6 while in Mexico; and after returning to Houston, Tex. (week 7). Fresh stool specimens were processed in two ways. First, a sample of approximately 1 mg was streaked onto MacConkey agar to obtain isolated colonies and incubated overnight at 37°C. As many as 10 isolated E. coli-like colonies were picked (fewer were picked only if 10 separate colonies could not be found) and inoculated into peptone stabs for transport back to Houston. This method is referred to as the 10-colony method. A second sample was streaked onto PW agar (per liter: 40 g of tryptic soy agar, 10 g of lactose, 1.5 g of bile salts, 0.001 g of crystal violet, 0.03 g of neutral red, and 50 IU of thymidine phosphorylase) contain...

“…The effect of trimethoprim (TMP) or TMP-sulfamethoxazole (SMX) treatment on the emergence of fecal bacteria has been studied by many investigators in different countries (2,4,8,10,14,15,(17)(18)(19). With one exception, little or no emergence of fecal TMP-resistant strains has been found in these studies.…”

mentioning

confidence: 99%

Emergence of trimethoprim resistance in fecal flora

Huovinen¹,

Mattila²,

Kiminki³

et al. 1985