Biomedical subjects

J G Wells

Publications and source records attributed to J G Wells.

At least 37 records · Page 2Linked to original sources

PubMed1997

Escherichia coli O157:H7 diarrhea in the United States: clinical and epidemiologic features.

BACKGROUND: Escherichia coli O157:H7 is increasingly recognized as a cause of bacterial diarrhea in the United States, but the frequency of its isolation and the clinical and epidemiologic features of E. coli O157:H7 infection in a large, geographically diverse population of patients have not been well described. OBJECTIVE: To determine the frequency of isolation of E. coli O157:H7 relative to that of other bacterial enteric pathogens in a nationwide sample of patients and to identify the clinical and epidemiologic features of E. coli O157:H7 infection. DESIGN: Population prevalence study from October 1990 to October 1992. SETTING: 10 U.S. hospitals. PATIENTS: Both inpatients and outpatients who had stool samples submitted to 1 of 10 laboratories for routine pathogen identification. MEASUREMENTS: Clinical, epidemiologic, and laboratory information was collected for infected and uninfected patients. Isolates of E. coli O157:H7 were tested for production of Shiga toxin. Patient charts were then reviewed. RESULTS: Escherichia coli O157:H7 was isolated from 118 (0.39%) of the 30463 fecal specimens tested. The proportion of fecal specimens with isolates was higher at northern sites (0.57%) than at southern sites (0.13%) (P < 0.001). Escherichia coli O157:H7 was more likely to be isolated from visibly bloody stool specimens than from specimens without visible blood (odds ratio [OR], 59.2 [95% CI, 36.6 to 96.0) and was the pathogen most commonly isolated from visibly bloody stool specimens that yielded a bacterial enteric pathogen (39% of such specimens). The highest age-specific isolation proportions from fecal specimens for E. coli O157:H7 were in patients 5 to 9 years of age (0.90%) and 50 to 59 years of age (0.89%). Clinical features independently associated with E. coli O157:H7 infection compared with the other enteric pathogens included a history of bloody diarrhea (OR, 18.6 [CI, 7.4 to 48.6]), visibly bloody stool specimens (OR, 8.1 [CI, 3.6 to 18.3]), no reported fever (OR, 8.3 [CI, 1.6 to 50.0]), leukocyte count greater than 10 x 10(9)/L (OR, 4.0 [CI, 1.7 to 9.5]), and abdominal tenderness on physical examination (OR, 2.9 [CI, 1.2 to 7.2]). CONCLUSIONS: In some geographic areas and some age groups, isolation proportions from fecal specimens for E. coli O157:H7 surpassed those of other common enteric pathogens. One third of isolates of this organism came from nonbloody specimens. Because person-to-person transmission of E. coli O157:H7 is not uncommon and infection with this organism may cause severe disease, stool specimens from all patients with a history of acute bloody diarrhea should be cultured for E. coli O157:H7.

Campylobacter Infections↗

PubMed1997

Hamburger-associated Escherichia coli O157:H7 infection in Las Vegas: a hidden epidemic.

OBJECTIVES: This study sought to determine whether a multistate fast food hamburger-associated outbreak of Escherichia coli O157:H7 infection involved Las Vegas residents as well and, if so, why public health officials had not detected it. METHODS: A matched case-control study was conducted among persons with bloody diarrhea and their healthy meal companions. Hamburger production, distribution, and cooking methods were reviewed. Unused hamburger patties were cultured, and E. coli O157:H7 isolates were characterized. Local laboratory stool culture practices were reviewed. RESULTS: Fifty-eight cases of bloody diarrhea were identified. Illness was associated with eating regular hamburgers (matched odds ratio [OR] = 9.0, 95% confidence interval [CI] = 1.02,433.4), but 25% of ill persons reported eating only jumbo hamburgers. Regular and jumbo hamburger patties yielded E. coli O157:H7 indistinguishable from the lone clinical isolate. No local laboratory cultured routinely for E. coli O157:H7 until after the outbreak. CONCLUSIONS: A large outbreak of E. coli O157:H7 infections escaped timely notice in Las Vegas because local laboratories did not culture for this pathogen. Health officials should encourage laboratories to screen at least all bloody stools on sorbitol-MacConkey medium.

Adolescent↗

PubMed1996

Epidemic cholera in Guatemala, 1993: transmission of a newly introduced epidemic strain by street vendors.

Epidemic cholera reached Guatemala in July 1991. By mid-1993, Guatemala ranked third in the hemisphere in reported cases of cholera. We conducted a case-control study with two age-, sex-, and neighbourhood-matched controls per patient in periurban Guatemala City. Twenty-six patients hospitalized for cholera and 52 controls were enrolled. Seven (47%) of 15 stool cultures obtained after admission yielded toxigenic Vibrio cholerae O1. All seven were resistant to furazolidone, sulfisoxazole, and streptomycin, and differed substantially by pulsed-field gel electrophoresis from the Latin American epidemic strain dominant in the hemisphere since 1991. In univariate analysis, illness was associated with consumption of left-over rice (odds ratio [OR] = 7.0, 95% confidence interval [CI] = 1.4-36), flavored ices (-helados') (OR = 3.6, CI = 1.1 - 12), and street-vended non-carbonated beverages (OR = 3.8, CI = 1.2-12) and food items (OR = 11.0, CI = 2.3-54). Street-vended food items remained significantly associated with illness in multivariate analysis (OR = 6.5, CI = 1.4-31). Illness was not associated with drinking municipal tap water. Maintaining water safety is important, but slowing the epidemic in Guatemala City and elsewhere may also require improvement in street vendor food handling and hygiene.

Adolescent↗

PubMed1996

Shiga-like toxin-producing Escherichia coli O111 and associated hemolytic-uremic syndrome: a family outbreak.

OBJECTIVE: To describe a family cluster of Shiga toxin-producing Escherichia coli O111ac:NM infection. STUDY DESIGN: The index case was identified as part of a United States prospective study of hemolytic-uremic syndrome. Epidemiologic investigation was conducted through interviews. E. coli O111:NM infection was characterized through culture and serology. Shiga toxin 1 and 2 gene sequences were determined with oligonucleotide DNA probes. RESULTS: All three children and both parents had nonbloody diarrhea, vomiting and abdominal cramps, and one child developed hemolytic-uremic syndrome. Shiga toxin 1- and 2-producing E. coli O111ac:NM was isolated from two children. IgG antibodies to E. coli O111 were detected in all three children. CONCLUSIONS: To our knowledge this is the first reported cluster of O111 infection and only the second caused by non-O157 Shiga toxin-producing E. coli in North America.

Bacterial Toxins↗

PubMed1996

Evaluation of commercial latex reagents for identification of O157 and H7 antigens of Escherichia coli.

Agglutination reactions obtained with three commercial latex reagents for detecting Escherichia coli O157 antigen (Oxoid Diagnostic Reagents, Hampshire, England; Pro-Lab Inc., Richmond Hill, Ontario, Canada; and Remel Microbiology Products, Lenexa, Kans.) and one for detecting H7 antigen (Remel) were compared with those obtained by standard serologic methods by using the Centers for Disease Control and Prevention (CDC) reference antisera for O157 and H7 antigens. For 159 strains of E. coli and related organisms, the Oxoid, Pro-Lab, and Remel O157 latex reagents each had a sensitivity and specificity of 100% compared with the CDC reference antiserum. For 106 strains of E. coli and related organisms that were not enhanced for motility through semisolid medium, the Remel H7 latex reagent had a sensitivity of 96% and a specificity of 100% compared with the standard tube agglutination method with CDC H7 antiserum. Measures to enhance motility were needed for some strains to detect the H7 antigen. Our findings demonstrate that the commercial latex reagents are good alternatives to standard serologic methods for identifying the O157 and H7 antigens of E. coli.

Antibodies, Bacterial↗

PubMed1995

Molecular subtyping of toxigenic Vibrio cholerae O139 causing epidemic cholera in India and Bangladesh, 1992-1993.

Since October 1992, > 150,000 cases of cholera have been reported from India and Bangladesh; the great majority of Vibrio cholerae isolates belong to the newly established serogroup O139. To better understand the interaction of genetic and epidemiologic factors responsible for their sudden appearance and rapid spread, representative toxigenic V. cholerae O139 isolates were molecularly characterized and compared with a set of toxigenic V. cholerae O1 and non-O1/non-O139 strains. DNA sequences of the cholera toxin B subunit gene and multilocus enzyme electrophoresis markers of V. cholerae O139 strains were identical to those of V. cholerae O1 isolates of the seventh pandemic. Two distinct ribotypes and four pulsed-field gel electrophoretic patterns were observed for O139 strains. V. cholerae O139 strains were very similar to V. cholerae O1 strains of the seventh pandemic but clearly different from the toxigenic V. cholerae strains of serogroups other than O1 and O139.

Bacterial Typing Techniques↗

PubMed1995

The emerging diversity of the electrophoretic types of Vibrio cholerae in the Western Hemisphere.

Since the Latin American cholera epidemic began in 1991, 447 isolates of Vibrio cholerae O1 from the Western Hemisphere have been assayed by multilocus enzyme electrophoresis (MEE) to determine allelic variation among 16 enzyme-encoding genes. Two electrophoretic types (ETs) were identified among toxigenic isolates from Latin America: 323 were ET 4, the ET associated with the Latin American epidemic, and 29 were ET 3. Twenty-three of these ET 3 isolates had a distinctive antimicrobial resistance pattern also seen in isolates imported into the United States from Latin America and Southeast Asia. These resistant isolates had an identical ribotype and nearly identical pulsed-field gel electrophoresis (PFGE) patterns. Most nontoxigenic isolates analyzed were not precursors or descendants of toxigenic epidemic strains. MEE provided a population genetic frame-work for the interpretation of PFGE and ribotype data from the isolates in this study. All three methods identified 2 distinct strains of toxigenic V. cholerae O1 currently epidemic in Latin America.

Asia, Southeastern↗

PubMed1995

A university outbreak of Escherichia coli O157:H7 infections associated with roast beef and an unusually benign clinical course.

An outbreak of Escherichia coli O157:H7 infections occurred after a graduation banquet at a university in Wisconsin. Sixty-one (32%) of 193 banquet attendees developed a gastrointestinal illness; 2 were hospitalized, none developed hemolytic-uremic syndrome or thrombotic thrombocytopenic purpura, and none died. The spectrum of illness was unusually mild, with 61% of ill persons reporting nonbloody diarrhea. A strain of E. coli O157:H7, indistinguishable from the outbreak strain by toxin type, plasmid profile, and pulsed-field gel electrophoresis, was isolated from an unopened package of an uncooked round of beef from the original shipment of meat. An investigation suggested that both undercooked roast beef and salad cross-contaminated with beef were vehicles of transmission. These findings demonstrate that meat from beef cattle may transmit E. coli O157:H7, and such infections among young to middle-aged adults may be mild and may often go undetected.

Adolescent↗

PubMed1995

Vibrio cholerae O139 Bengal infections among tourists to Southeast Asia: an intercontinental foodborne outbreak.

To determine the source and extent of an outbreak of Vibrio cholerae O139 Bengal infections among 630 cruise ship passengers to Southeast Asia, a retrospective cohort study was done. Questionnaires were sent to all passengers from the United States, Canada, and the United Kingdom, and serum samples were requested from all passengers reporting diarrhea. A case was defined as diarrheal illness with onset between 8 and 28 February 1994 and a cholera antitoxic antibody titer > or = 800. Six passengers, including 1 with bacteremia, met the case definition. Illness was associated with eating yellow rice at a buffet restaurant in Bangkok on 10 February (relative risk undefined, P = .005). This international outbreak demonstrates foodborne transmission of Vibrio cholerae O139 Bengal, an emerging cause of epidemic cholera in Asia, to tourists from Western countries. Physicians should suspect infection with either V. cholerae O1 or O139 in any patient with severe watery diarrhea after travel to the developing world.

Aged↗

PubMed1995

Screening for Escherichia coli O157:H7--a nationwide survey of clinical laboratories.

The Association of State and Territorial Public Health Laboratory Directors has recommended that clinical laboratories screen at least all bloody stools for Escherichia coli O157:H7. We contacted the microbiology supervisors of 230 randomly selected clinical laboratories in the United States and administered a standardized questionnaire regarding stool culture practices. Of the 129 laboratories that performed stool cultures, only 70 (54%) reported screening either all stools or all bloody stools submitted for culture for E. coli O157:H7.

Data Collection↗

PubMed1994

A multistate outbreak of Escherichia coli O157:H7-associated bloody diarrhea and hemolytic uremic syndrome from hamburgers. The Washington experience.

OBJECTIVE: To determine the source of and describe a large outbreak of Escherichia coli O157:H7 infections in Washington State. DESIGN: Case-control study; environmental investigation; provider-based surveillance for E coli O157:H7 infections. SETTING: Chain of fast-food restaurants, hospitals, physician offices, local laboratories, and local health departments. PARTICIPANTS: Patients with diarrhea and neighborhood controls. A case was defined as diarrhea with culture-confirmed E coli O157:H7 infection or postdiarrheal hemolytic uremic syndrome (HUS) occurring from December 1, 1992, through February 28, 1993, in a Washington State resident. Controls were age- and neighborhood-matched friends of the first 16 case patients. INTERVENTIONS: Announcement to the public; recall of implicated hamburger lots. MAIN OUTCOME MEASURE: Abatement of outbreak due to E coli O157:H7. RESULTS: Infection was associated with eating at a fast-food chain (chain A) in the 10 days before symptoms began. Twelve (75%) of 16 case patients but no controls had eaten at chain A (matched odds ratio undefined; lower 95% confidence interval, 3.5; P < .001). In total, 501 cases were reported, including 151 hospitalizations (31%), 45 cases of HUS (9%), and three deaths. Forty-eight patients (10%) had secondary infections. Of the remaining 453 patients (90%), 398 (86%) reported eating at a Washington chain A restaurant; 92% of them reported eating a regular hamburger. The pulsed-field gel electrophoresis pattern of the E coli O157:H7 strains isolated from all regular hamburger lots of a single production date shipped to Washington was identical to that of the strains isolated from patients. Ten (63%) of 16 regular hamburgers cooked according to chain A policy had internal temperatures below 60 degrees C. Public health action removed more than 250,000 potentially contaminated hamburgers, preventing an estimated 800 cases. CONCLUSIONS: This E coli O157:H7 outbreak, the largest reported, resulted from errors in meat processing and cooking. Public health surveillance through state-mandated reporting of E coli O157:H7 infection as is carried out in Washington State was critical for prompt outbreak recognition and control. Measures should be developed to reduce meat contamination. Consumers and food service workers should be educated about cooking hamburger meat thoroughly.

Adolescent↗

PubMed1994

Epidemic Shigella dysenteriae type 1 in Burundi: panresistance and implications for prevention.

An epidemic of Shigella dysenteriae type 1 infections has affected Africa since 1979. Reported dysentery cases increase sharply in Burundi during September through December. Of stool samples from 189 patients reporting bloody diarrhea in November 1990, a pathogen was identified in 123 (65%). The pathogen was S. dysenteriae type 1 in 82 (67%). All S. dysenteriae type 1 isolates were resistant to ampicillin, chloramphenicol, nalidixic acid, streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole. Thirty-two specimens (26%) yielded other Shigella species. Patients with S. dysenteriae type 1 were more likely than those with other Shigella infections to have abdominal pain, "lots of blood" in the stool, blood in the stool specimen examined by the interviewer, recent contact with a person with dysentery, or recent antimicrobial treatment. Thus, the seasonal increase in dysentery was due largely to multidrug-resistant S. dysenteriae type 1, clinical and epidemiologic features may predict such infection, and efforts to control this epidemic must focus on preventing transmission.

Adolescent↗

PubMed1994

Laboratory investigation of a multistate food-borne outbreak of Escherichia coli O157:H7 by using pulsed-field gel electrophoresis and phage typing.

Two hundred thirty-three isolates of Escherichia coli O157:H7 were analyzed by both pulsed-field gel electrophoresis (PFGE) and bacteriophage typing. All 26 isolates from persons whose illness was associated with a recent multistate outbreak of E. coli O157:H7 infections linked to the consumption of undercooked hamburgers and all 27 isolates from incriminated lots of hamburger meat had the same phage type and the same PFGE pattern. Twenty-five of 74 E. coli O157:H7 isolates from Washington State and 10 of 27 isolates from other states obtained during the 6 months before the outbreak had the same phage type as the outbreak strain, but only 1 isolate had the same PFGE pattern. PFGE thus appeared to be a more sensitive method than bacteriophage typing for distinguishing outbreak and non-outbreak-related strains. The PFGE patterns of seven preoutbreak sporadic isolates and five sporadic isolates from the outbreak period differed from that of the outbreak strain by a single band, making it difficult to identify these isolates as outbreak or non-outbreak related. Phage typing and PFGE with additional enzymes were helpful in resolving this problem. While not as sensitive as PFGE, phage typing was helpful in interpreting PFGE data and could have been used as a simple, rapid screen to eliminate the need for performing PFGE on unrelated isolates.

Animals↗

PubMed1994

Recombinant tissue inhibitor of metalloproteinases type 1 suppresses alkali-burn-induced corneal ulceration in rabbits.

PURPOSE: To test if recombinant tissue inhibitor of metalloproteinases (TIMP-1) was effective in reducing corneal ulceration after alkali injury to the rabbit cornea. The effect of TIMP-1 was compared with that of a proven synthetic metalloproteinase inhibitor. METHODS: After a defined alkali injury to the rabbit cornea, a topical treatment regimen was followed for 24 days; one group was treated with vehicle only, a second group with recombinant TIMP-1, and a third group with the synthetic metalloproteinase inhibitor. Corneas were scored for ulceration during the 24-day period and the scores for the three groups were compared. RESULTS: The incidence and progression of ulceration and perforation, in the alkali-burned corneas receiving treatment with recombinant TIMP-1 or the synthetic inhibitor, were significantly less than in corneas receiving vehicle treatment alone. CONCLUSION: Recombinant TIMP-1 is as effective as a proven synthetic inhibitor in ameliorating corneal ulceration and perforation after an alkali injury.

Administration, Topical↗

PubMed1993

An outbreak of diarrhea and hemolytic uremic syndrome from Escherichia coli O157:H7 in fresh-pressed apple cider.

OBJECTIVE: Escherichia coli O157:H7 causes hemorrhagic colitis and the hemolytic uremic syndrome. In the fall of 1991, an outbreak of E coli O157:H7 infections in southeastern Massachusetts provided an opportunity to identify transmission by a seemingly unlikely vehicle. DESIGN: Case-control study to determine the vehicle of infection. New England cider producers were surveyed to assess production practices and determined the survival time of E coli O157:H7 organisms in apple cider. RESULTS: Illness was significantly associated with drinking one brand of apple cider. Thirteen (72%) of 18 patients but only 16 (33%) of 49 controls reported drinking apple cider in the week before illness began (odds ratio [OR], 8.3; 95% confidence interval [CI], 1.8 to 39.7). Among those who drank cider, 12 (92%) of 13 patients compared with two (13%) of 16 controls drank cider from cider mill A (lower 95% CI, 2.9; P < .01). This mill pressed cider in a manner similar to that used by other small cider producers: apples were not washed, cider was not pasteurized, and no preservatives were added. In the laboratory, E coli O157:H7 organisms survived for 20 days in unpreserved refrigerated apple cider. Addition of sodium benzoate 0.1% reduced survival to less than 7 days. CONCLUSIONS: Fresh-pressed, unpreserved apple cider can transmit E coli O157:H7 organisms, which cause severe infections. Risk of transmission can be reduced by washing and brushing apples before pressing, and preserving cider with sodium benzoate. Consumers can reduce their risk by only drinking cider made from apples that have been washed and brushed.

Adolescent↗

PubMed1993

The molecular epidemiology of cholera in Latin America.

To explain the sudden appearance and rapid spread of cholera in Latin America in January 1991, molecular techniques were used to define Vibrio cholerae O1 isolates from around the world. Restriction fragment length polymorphisms of rRNA and ctxA genes, DNA sequence of cholera toxin B subunit gene ctxB, and multilocus enzyme electrophoresis data were used to characterize 197 isolates. Worldwide, there are at least four distinct toxigenic El Tor V. cholerae O1 clones: the seventh pandemic (Eastern Hemisphere), US Gulf Coast, Australian, and Latin American. Nontoxigenic V. cholerae O1 previously isolated in Brazil, Mexico, and Peru are unlike current toxigenic isolates. The Latin American clone probably represents an extension of the seventh pandemic into the Western Hemisphere, while the US Gulf Coast clone most likely evolved separately. These data will be useful in monitoring the spread of cholera, determining the origin of outbreaks in both hemispheres, and implicating specific vehicles of transmission.

Alleles↗

PubMed1992

A waterborne outbreak in Missouri of Escherichia coli O157:H7 associated with bloody diarrhea and death.

OBJECTIVE: To describe and determine the source of a large outbreak of Escherichia coli O157:H7 (ECO157) infections in Missouri. DESIGN: A case-control study and a household survey. SETTING: A small city in a rural Missouri township that had an unchlorinated water supply. PATIENTS: Case patients were residents of or visitors to Burdine Township with bloody diarrhea or diarrhea and abdominal cramps occurring between 15 December 1989 and 20 January 1990. MEASUREMENTS: Escherichia coli O157 was isolated from 21 stool specimens. All isolates were resistant to sulfisoxazole, tetracycline, and streptomycin; produced Shiga-like toxins I and II; and had one 60-megadalton plasmid. RESULTS: Among the 243 case patients, 86 had bloody stools, 32 were hospitalized, 4 died, and 2 had the hemolytic uremic syndrome. In the case-control study, no food was associated with illness, but ill persons had drunk more municipal water than had controls (P = 0.04). The survey showed that, during the peak of the outbreak, bloody diarrhea was 18.2 times more likely to occur in persons living inside the city and using municipal water than in persons living outside the city and using private well water (P = 0.001). Shortly before the peak of the outbreak, 45 water meters were replaced, and two water mains ruptured. The number of new cases declined rapidly after residents were ordered to boil water and after chlorination of the water supply. CONCLUSIONS: This was the largest outbreak of ECO157 infections, the first due to a multiply resistant organism, and the first shown to be transmitted by water. System-wide chlorination as well as hyperchlorination during repairs might have prevented this outbreak. Both bloody and nonbloody diarrhea may be common manifestations of this infection, which is probably underdiagnosed because of the failure of routine stool cultures to identify the organism. Cities with deteriorating water systems using untreated water risk widespread illness from contaminated drinking water.

Adolescent↗

PubMed1992

Hemolytic uremic syndrome due to Escherichia coli O157: H7 in a child with multiple infections.

Hemolytic uremic syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia, and uremia; it is a common cause of acute renal failure in children. Although many microbial agents have been associated with HUS, only Escherichia coli O157: H7 has been clearly demonstrated to be a major cause of this illness. A case is presented of a healthy 4-year-old boy who had a recent varicella infection; when evaluated for HUS his blood and stool cultures both grew Salmonella montevideo and blood cultures grew group A beta-hemolytic streptococci. A stool cultured on MacConkey-sorbitol agar also grew E. coli O157: H7. An eightfold rise in serum antibodies to E. coli O157: H7 lipopolysaccharide was also demonstrated. The child recovered completely and was healthy 3 years later. Although this child had several infectious agents anecdotally associated with HUS, appropriate culture of stool showed that he also had E. coli O157: H7 infection. Previous cases thought to be due to other pathogens may similarly have been caused by co-infection with E. coli O157: H7.

Antibodies, Bacterial↗