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Biomedical subjects

R R Reves

Publications and source records attributed to R R Reves.

49 records · Page 3Linked to original sources
PubMed1990

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

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 less than 0.001 to P less than 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.

Anti-Bacterial Agents↗
PubMed1990

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

In a previous study, we found fecal colonization with multiresistant Escherichia coli 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 less than 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 less than 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.

Adolescent↗
PubMed1990

Infections in child day care centers as they relate to internal medicine.

Internists should be aware of the increased frequency of most communicable diseases among parents and child care providers exposed to children attending child day care centers. Episodes of shigellosis and hepatitis A among adults in contact with children in day care centers should be promptly reported to public health authorities, since they may indicate the presence of a day care center outbreak for which effective control measures are available. Although effective treatment or intervention is limited or not available for many other infections acquired by adults from children in day care centers, significant illness may result in a minority of individuals at increased risk for infection with agents such as cytomegalovirus and varicella. Acute infectious diseases of children caused by organisms transmitted from day care center staff are less common and largely preventable by ensuring that staff are appropriately immunized and screened for tuberculosis.

Adult↗
PubMed1990

Shiftwork and industrial injuries at a chemical plant in southeast Texas.

A historical retrospective study of 242 shiftworker (SW) and 224 non-SW (NSW) injuries at a chemical manufacturing plant in southeast Texas (U.S.A.) was performed. Data were collected on injuries that occurred between 1 January 1982 and 31 December 1985. The SW schedule comprised an 8-hr, 7-day backward rotation program while the dayworker schedule consisted of a typical U.S.A. 40-hr work week. Injury records were matched against payroll/attendance records to substantiate the probability of isolating possible effects of the shiftwork rotation schedule on the rates, distribution and severity of injuries. Injuries in the SW sample were compared to those in the non-SW sample. The work responsibilities of dayworkers were not exactly the same as those of shiftworkers. However, the job responsibilities for males and females within the dayworker and shiftworker groups were equivalent. Overall injury incidence rates were not significantly different between SWs and non-SWs, although female SWs had significantly higher incidence rates than did male SWs and both male and female dayworkers. The occurrence of injuries, however, was not equally distributed during the day shift and the night shift, but was equally distributed during the evening shift and for non-SWs, suggesting that certain, yet to be determined, factors were affecting the distribution of injuries during the day and night shift. However, the average number of injuries was two-three times higher during the first four days of the day and night shift, yet were not elevated during the evening shift.

Accidents, Occupational↗
PubMed1989

An observational study of naturally acquired immunity to rotaviral diarrhea in a cohort of 363 Egyptian children. Calculation of risk for second episodes using age-specific person-years of observation.

A cohort of 363 rural children in Bilbeis, Egypt, were followed from birth from 1981 to 1983, with twice-weekly home visits made to detect diarrheal illness. Enzyme-linked immunosorbent assay was used for detection of rotavirus in stools collected during episodes of diarrhea. Rotavirus-associated diarrhea was detected once in 74 children and twice in 12 children. Using a technique not previously described, the authors calculated the age-specific incidence rates for initial episodes and second episodes of rotavirus-associated diarrhea to estimate the effectiveness of naturally acquired immunity. Assuming that the risk of exposure was the same before and after the first episode, the observed and expected numbers of second episodes of rotaviral diarrhea were equal (age-adjusted rate ratio = 1.01; 95 percent confidence interval 0.55-1.86), given the age-specific person-years at risk. The assumption of equal risk for reexposure to rotavirus appears to be invalid, however, since the children with one and two rotavirus-positive episodes appeared to be at greater risk for diarrheal illness of all causes (rate ratios of 1.42 and 1.78, respectively). The clinical illness may have been less severe in second episodes; emesis was reported more often with first rotavirus episodes than with second rotavirus episodes, and the only fatal case was in an initial episode. These data are compatible with the existence of partial immunity, since it appears that the risk of reexposure may be greater in children who experienced rotaviral gastroenteritis earlier in life. In four of seven children, rotavirus isolates from first and second episodes were of identical serotypes, indicating that even serotype-specific immunity for rotaviral diarrhea was incomplete.

Age Factors↗
PubMed1988

Asymptomatic excretion of rotavirus before and after rotavirus diarrhea in children in day care centers.

A 12-month prospective study of diarrhea in children in day care centers (DCCs) provided an opportunity to evaluate the duration of excretion of rotavirus from children before and after episodes of diarrhea caused by rotavirus. Ninety-nine episodes of rotavirus diarrhea occurred in 94 children. Asymptomatic rotavirus excretion occurred in 50% of children tested on the day before diarrhea occurred, 31% two days before diarrhea, and 9% in days 3 through 5 before diarrhea. Two children had positive specimens 11 and 13 days, respectively, before illness. During the week after cessation of diarrhea, 32% had positive specimens; 12% had positive stool specimens during the second week after diarrhea episodes. Electrophoretic testing of rotavirus RNA from stool specimens showed different electrophoretic migration patterns of the genomic RNA among the pairs tested, but the genomic RNA was the same within each pair of symptomatic and asymptomatic specimens. Excretion of rotavirus before and after diarrhea is common in children in DCCs; the role that asymptomatic excretion plays in the spread of this disease within DCCs is unknown.

Child Day Care Centers↗
PubMed1988

Rotavirus in infant-toddler day care centers: epidemiology relevant to disease control strategies.

A 15-month prospective longitudinal study of diarrhea and rotavirus (RV) infection was conducted concurrently in infants and toddlers in day care centers (DCCs) and in a large pediatric clinic in Houston. The mean number of children in the DCCs was 223; the diarrhea rate during the first 12 months was 2.62 episodes per child-year. Rotavirus accounted for approximately 10% of the total episodes of diarrhea in the pediatric clinic and DCC populations, but 50% during the winter months. The occurrence of RV in the DCCs paralleled that seen in the pediatric clinic. The annual rate of RV infection in DCCs was 0.55 episodes per child-year, with diarrhea occurring in only 40% of the episodes (0.22 episodes per child-year). There were 45 diarrhea outbreaks in DCCs, for a mean of 3.8 per center per year; nine of these outbreaks were associated with RV. Polyacrylamide gel electrophoresis of RNA genome patterns of RV strains from eight of these outbreaks showed that in seven outbreaks a single strain was identified in children in that DCC, whereas multiple strains were identified simultaneously in the community. The age distributions of symptomatic and asymptomatic RV infections in DCC study children were not significantly different. In symptomatic RV-infected children in DCCs, 42% had RV identified in stool specimens within 2 days before diarrhea occurred. Thirty-eight DCC children had more than one episode of RV infection, but only five had two symptomatic RV infections. Diarrhea caused by RV is common in children in DCCs, often occurs in outbreaks due to the same strain, and parallels disease in the community; asymptomatic RV infection is also common in children in DCCs.

Child Day Care Centers↗
PubMed1988

A cost-effectiveness comparison of the use of antimicrobial agents for treatment or prophylaxis of travelers' diarrhea.

We conducted a decision analysis to compare the cost-effectiveness of antimicrobial agents used for treatment with their use for prophylaxis of travelers' diarrhea. Estimates of the likelihood and the cost of various outcomes were obtained from a panel of experts using the Delphi group opinion technique. Treatment with sulfamethoxazole-trimethoprim for three days was compared with daily prophylaxis with sulfamethoxazole-trimethoprim or doxycycline. The cost-effectiveness of prophylaxis with either agent (75% to 83%) was greater than that of treatment (38%). Treatment would become more cost-effective than prophylaxis when the cumulative risk of acquiring travelers' diarrhea was less than 0.05 episodes per person per week or if the effectiveness of prophylaxis fell below 35% for doxycycline and 46% for sulfamethoxazole-trimethoprim. The most important contributor to the mean cost of travelers' diarrhea in this analysis was the cost associated with a day of incapacitation due to illness. On the basis of the results of this decision analysis, we conclude that prophylaxis of travelers' diarrhea is an option that should be considered for individual situations and recommend further studies of its cost-effectiveness.

Anti-Bacterial Agents↗
PubMed1987

Children with trimethoprim- and ampicillin-resistant fecal Escherichia coli in day care centers.

We conducted a cross-sectional study of 79 children attending seven day care centers in Houston, Texas, to detect fecal gram-negative bacilli resistant to trimethoprim (TMPr) and ampicillin (AMPr). Fifteen children (19%) were colonized with TMPr Escherichia coli; all but one strain were also resistant to sulfonamides. Most of the children with TMPr E. coli were clustered in center A, where 11 (37%) of 30 children were colonized; only four (8%) of 49 children in the other six centers were colonized with TMPr E. coli (P less than .005). The TMPr E. coli isolates from 10 of the 11 children in Center A had a similar antibiogram, which included resistance to sulfonamides, ampicillin, and streptomycin; eight had a similar total plasmid pattern, an observation suggesting spread within the day care center. Children colonized with AMPr E. coli were present in all centers, although a higher percentage of children in center A were colonized than in the other centers combined (70% vs. 35%; P less than .01).

Ampicillin Resistance↗
PubMed1982

Treatment of travelers' diarrhea with trimethoprim/sulfamethoxazole and with trimethoprim alone.

We conducted a double-blind treatment study of 110 adults from the United States who were attending summer classes in Guadalajara, Mexico, and had diarrhea (four or more unformed stools in 24 hours, or three or more unformed stools per eight-hour period plus one or more additional clinical indicators of enteric infection). Thirty-seven patients received trimethoprim/sulfamethoxazole (TMP/SMX) (160 mg of TMP and 800 mg of SMX), 38 were given TMP alone (200 mg), and 35 took a placebo twice daily for five days. By the end of the first 24 hours of treatment, patients taking either TMP/SMX or TMP alone passed fewer unformed stools than did patients given placebo (P = 0.0002 and P = 0.01, respectively). Abdominal pain and nausea were reduced in both treatment groups. The beneficial effect was seen in treatment of Escherichia coli-induced diarrhea, shigellosis, and diarrhea not associated with an enteropathogen. Five per cent of patients given TMP/SMX, 8 per cent of those given TMP, and 49 per cent of those given placebo were considered treatment failures (P less than 0.001 for both active drugs as compared with placebo). Early treatment with TMP/SMX or TMP is an alternative to prophylactic use of drugs for travelers' diarrhea.

Adult↗
PubMedDate not supplied

Antimicrobial therapy for travelers' diarrhea.

Three clinical trials were carried out to examine the efficacy of various antimicrobial agents in the treatment of travelers' diarrhea among students from the United States in Mexico. Thirty-seven subjects received twice daily for five days 160 mg of trimethoprim (TMP) and 800 mg of sulfamethoxazole (SMZ), 38 received 200 mg of TMP, and 35 received a placebo. Another group of students were given 100 mg of furazolidone (47 students) or ampicillin (47 students) four times a day for five days. In the third study, 500 mg of bicozamycin (72 students) or a placebo (68 students) was given four times a day for three days. Most students who received TMP-SMZ (78%), TMP (84%), or bicozamycin (85%) had recovered by 48 hr after initiation of treatment, as compared with 14% and 47% in the corresponding placebo groups and 55% in the furazolidone group. The agents had a positive effect for all etiologic categories, including diarrhea due to enterotoxigenic Escherichia coli and Shigella strains and illness without any established etiologic agents. Treatment failures were unusual with TMP-SMZ, TMP, and bicozamycin therapy (5% vs. 39% for the placebo-treated students). The drugs were well tolerated. The use of TMP-SMZ or TMP alone in the empiric treatment of moderate to severe travelers' diarrhea is advocated.

Adult↗