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Biomedical subjects

B R Davis

Publications and source records attributed to B R Davis.

At least 145 records · Page 8Linked to original sources
PubMed1983

Hemorrhagic colitis associated with a rare Escherichia coli serotype.

We investigated two outbreaks of an unusual gastrointestinal illness that affected at least 47 people in Oregon and Michigan in February through March and May through June 1982. The illness was characterized by severe crampy abdominal pain, initially watery diarrhea followed by grossly bloody diarrhea, and little or no fever. It was associated with eating at restaurants belonging to the same fast-food restaurant chain in Oregon (P less than 0.005) and Michigan (P = 0.0005) and with eating any of three sandwiches containing three ingredients in common (beef patty, rehydrated onions, and pickles). Stool cultures did not yield previously recognized pathogens. However, a rare Escherichia coli serotype, O157:H7, that was not invasive or toxigenic by standard tests was isolated from 9 of 12 stools collected within four days of onset of illness in both outbreaks combined, and from a beef patty from a suspected lot of meat in Michigan. The only known previous isolation of this serotype was from a sporadic case of hemorrhagic colitis in 1975. This report describes a clinically distinctive gastrointestinal illness associated with E. coli O157:H7, apparently transmitted by undercooked meat.

Adolescent↗
PubMed1983

Laboratory investigation of hemorrhagic colitis outbreaks associated with a rare Escherichia coli serotype.

Two outbreaks of hemorrhagic colitis, a newly recognized syndrome characterized by bloody diarrhea, severe abdominal pain, and little or no fever, occurred in 1982. No previously recognized pathogens were recovered from stool specimens from persons in either outbreak. However, a rare E. coli serotype, O157:H7, was isolated from 9 of 20 cases and from no controls. It was also recovered from a meat patty from the implicated lot eaten by persons in one outbreak. No recovery of this organism was made from stools collected 7 or more days after onset of illness; whereas 9 of 12 culture-positive stools had been collected within 4 days of onset of illness. The isolate was not invasive or toxigenic by standard tests, and all strains has a unique biotype. Plasmid profile analysis indicates that all outbreak-associated E. coli O157:H7 isolates are closely related. These results suggest that E. coli O157:H7 was the causative agent of illness in the two outbreaks.

Anti-Bacterial Agents↗
PubMed1983

Parametric studies of tinnitus masking and residual inhibition.

A study was made of the relation between tinnitus masker composition (frequency, bandwidth, intensity duration) and the time course and magnitude of residual inhibition (RI). RI was determined by methods of (a) loudness estimation - where the subject varied the pointer position on a loudness scale (b) loudness balance - where the tinnitus loudness was maintained in loudness balance in the period following masking with a tone of variable intensity presented to the opposite ear. In addition, sensitivity change (temporary threshold shift, TTS) in the tinnitus and masker frequency regions was measured by determining tone thresholds (using a tracking technique) before and after masker presentation. The key findings were as follows: (I) RI depends on masker centre frequency. The frequency producing maximal RI is usually lower than the tinnitus frequency (as determined by pitch matching). (2) In some subjects only narrow-band noise produces RI. (3) RI is proportional to the masker intensity provided the tinnitus is completely masked; little or no RI is produced by a partial masker. (4) For the masker durations used (in the range 10 s to 10 min) RI duration is linearly related to the logarithm of masker duration. (5) A second masker presentation during RI does not potentiate RI. (6) Contralateral masking did not produce RI. (7) maskers producing RI also produce TTS around the tinnitus frequency. (8) The TTS magnitude and the time course of TTS appear to be related to RI.

Acoustics↗
PubMed1983

Yersinia enterocolitica pharyngitis.

During the investigation of a large multistate outbreak of milk-borne yersiniosis, 14 patients who presented with pharyngitis had Yersinia enterocolitica isolated from the throat. Their illness was characterized by sore throat and fever without enteritis; 3 needed hospitalization. All patients tested had leukocytosis and an elevated convalescent-phase serum titer against the outbreak strain. In contrast to patients with enteritis, who were children, all patients with pharyngitis were adults. Thus, Y. enterocolitica may be responsible for some sporadic cases of pharyngitis in which the throat culture is negative for other pathogens.

Adolescent↗
PubMed1983

Acute febrile neutrophilic dermatosis in children. Report of two cases in male infants.

Two male infants manifested a complex of symptoms and signs that we believed represented a distinctive hypersensitivity disease, with features of acute febrile neutrophilic dermatosis and allergic vasculitis. Both were less than 1 year of age, and both acquired their disease during or after an upper respiratory illness. Each infant was initially seen with waxy and erythematous to slightly violaceous papules that enlarged to form plaques. The lesions developed at sites of trauma and were distributed on the trunk, face, and extremities. Both infants were febrile and had leukocytosis. On histopathologic examination, biopsy specimens taken from the lesions demonstrated a pronounced dermal infiltration of polymorphonuclear leukocytes. These lesions responded to treatment with prednisone and topical fluorinated corticosteroids, healed with scarring, and recurred after initial improvement.

Acute Disease↗
PubMed1983

Disease from infection with Vibrio mimicus, a newly recognized Vibrio species.

Clinical and epidemiologic characteristics of disease associated with a newly described nonhalophilic Vibrio species, Vibrio mimicus, were identified by studying isolates from 21 patients referred to the Centers for Disease Control between 1977 and 1981. Two isolates were from the ears of patients with otitis who had recently been exposed to seawater. Nineteen isolates were from stool samples; these patients generally had diarrhea, nausea, vomiting, and abdominal cramps, with fever, headache, and bloody diarrhea occurring in fewer than half. Persons with diarrhea were more likely than age- and sex-matched controls to have eaten raw oysters (p = 0.013). Although most cases were sporadic, three were associated with a single outbreak. Only two isolates produced toxin found by enzyme-linked immunosorbent assay or the Y-1 adrenal cell assay for heat-labile toxin, and none produced heat-stable toxin found by the infant mouse assay. Vibrio mimicus should be considered in the differential diagnosis of acute gastroenteritis occurring after recent ingestion of seafood (especially raw oysters) and in acute otitis after exposure to seawater.

Adolescent↗
PubMed1983

Disease from infection with Vibrio mimicus, a newly recognized Vibrio species. Clinical characteristics and edipemiology.

Clinical and epidemiologic characteristics of disease associated with a newly described nonhalophilic Vibrio species, Vibrio mimicus, were identified by studying isolates from 21 patients referred to the Centers for Disease Control between 1977 and 1981. Two isolates were from the ears of patients with otitis who had recently been exposed to seawater. Nineteen isolates were from stool samples; these patients generally had diarrhea, nausea, vomiting, and abdominal cramps, with fever, headache, and bloody diarrhea occurring in fewer than half. Persons with diarrhea were more likely than age- and sex-matched controls to have eaten raw oysters (p = 0.013). Although most cases were sporadic, three were associated with a single outbreak. Only two isolates produced toxin found by enzyme-linked immunosorbent assay or the Y-1 adrenal cell assay for heat-labile toxin, and none produced heat-stable toxin found by the infant mouse assay. Vibrio mimicus should be considered in the differential diagnosis of acute gastroenteritis occurring after recent ingestion of seafood (especially raw oysters) and in acute otitis after exposure to seawater.

Adolescent↗
PubMed1982

Atypical biogroups of Escherichia coli found in clinical specimens and description of Escherichia hermannii sp. nov.

DNA relatedness was used to define the biochemical boundaries of Escherichia coli. A large number of biochemically atypical strains were shown to belong to biogroups of E. coli. These included strains negative in reactions for indole, all three decarboxylases, D-mannitol, lactose, or methyl red and strains positive in reactions for H2S, urea, citrate, KCN, adonitol, myo-inositol, or phenylalanine deaminase. Frequency and source data are presented for these atypical E. coli biogroups. One group of KCN-positive, cellobiose-positive, yellow-pigmented strains was 84 to 91% interrelated but only 35 to 45% related to E. coli. The name Escherichia hermannii sp. nov. is proposed for this group of organisms that was formerly called Enteric Group 11 by the Enteric Section, Centers for Disease Control, Atlanta, GA. Twenty-nine strains of E. hermannii have been isolated in the United States from a variety of clinical sources, principally wounds, sputum, and stools. Three additional strains were isolated from food. E. hermannii strains are gram-negative, oxidase-negative, fermentative, motile rods. In addition to yellow pigment and positive KCN and cellobiose tests, the biochemical reactions characteristic of 32 strains of E. hermannii were as follows: gas from D-glucose, acid from D-glucose, maltose, D-xylose, L-arabinose, L-rhamnose, and D-mannitol; no acid from adonitol or inositol; variable acid production from lactose and sucrose; positive tests for indole, methyl red, and mucate; negative tests for Voges-Proskauer. Simmons citrate, H2S, urea, phenylalanine deaminase, and gelatin hydrolysis; negative or delayed test for L-lysine decarboxylase and negative test for L-arginine dihydrolase; and positive test for ornithine decarboxylase. E. hermannii strains were resistant to penicillin, ampicillin, and carbenicillin and sensitive to other commonly used antibiotics. Wounds account for almost 50% of human isolates of E. hermannii, followed by sputum or lung isolates (ca. 25%) and stool isolates (20%).

Anti-Bacterial Agents↗
PubMed1982

Serological comparison of two collections of Vibrio cholerae non O1.

Two large, independently obtained collections of vibrio cholerae non O1, containing 59 and 67 reference strains, respectively, were compared serologically in four laboratories. Twenty strains in each collection were considered identical, and an additional 16 strains in each collection were probably identical. Twenty-eight unique strains were identified, and inconclusive results were obtained with 25 strains. Nine strains were not considered V. cholerae in at least one testing laboratory. Of these, five showed insufficient correspondence to V. cholerae O1 by DNA hybridization to be considered V. cholerae.

Agglutination Tests↗
PubMed1981

Pyoderma gangrenosum treated with clofazimine. Report of three cases.

Three cases of pyoderma gangrenosum (PG) responsive to clofazimine are reported. The ulcers were recalcitrant to other forms of therapy, and the patients were incapacitated. Healing began within 2 or 3 weeks. To our knowledge, these are the first reported cases of PG responsive to clofazimine in the United States.

Chronic Disease↗
PubMed1981

Characterization of biochemically atypical Vibrio cholerae strains and designation of a new pathogenic species, Vibrio mimicus.

Biochemically atypical strains classified as Vibrio cholerae were characterized by biochemical reactions, serology, antibiotic susceptibility testing, and deoxyribonucleic acid relatedness. Strains with the following atypical reactions were shown to be V. cholerae: mannose negative, mannitol negative, lysine decarboxylase negative, no growth in the presence of 5% NaCl, salicin and cellobiose positive. Sucrose-negative strains were shown to constitute a new species, Vibrio mimicus, whose type strain is 1721-77 (ATCC 33653). In addition to its negative sucrose reaction, V mimicus was differentiated from V. cholerae by its negative Voges-Proskauer, corn oil, and Jordan tartrate reactions and by its sensitivity to polymyxin. V. mimicus was isolated from shellfish and water, as well as from human diarrheal stools and ear infections. Most strains were typable with antisera against V. cholerae. Strains from three serogroups produced either a heat-labile or a heat-stable enterotoxin.

Bacteriological Techniques↗
PubMed1981

Non-O group 1 Vibrio cholerae gastroenteritis in the United States: clinical, epidemiologic, and laboratory characteristics of sporadic cases.

Fourteen sporadic cases of non-O group 1 Vibrio cholerae gastroenteritis were identified through isolates submitted to the Centers for Disease Control in 1979. All the ill persons had diarrhea, 13 had abdominal cramps, 10 had fever, and three had vomiting; in four cases the patients had bloody diarrhea. Five patients had traveled outside the United States before they became ill. All nine domestically acquired cases were in patients who had eaten raw oysters within 72 hours of onset of illness; in a matched case-control study, illness in these patients was strongly associated with eating raw seafood (p less than 0.0001). Only one isolate produced heat-labile toxin by a Y-1 adrenal cell assay. All isolates were susceptible to tetracycline, chloramphenicol, kanamycin, and cephalothin.

Adult↗
PubMed1980

Serotypes of enterotoxigenic Escherichia coli isolated in the United States.

Strains of enterotoxigenic Escherichia coli isolated from humans in the United States were found in 11 of 16 serotypes that previously were documented in the international literature as associated with enterotoxin production. Of 68 strains belonging to these 11 serotypes, 28 (41%) were enterotoxigenic; none of 46 strains belonging to 5 other previously implicated serotypes was enterotoxigenic. Control cultures of various serotypes were selected for comparison and found to contain 0 to 7% enterotoxigenic E. coli. E. coli belonging to documented enterotoxin-associated serotypes, characterized by both O and H antigens, were selected for toxin testing to determine their prevalence and potential pathogenicity in this country. In this study, a strain possessing any combination of an enterotoxin-associated serotype O antigen and H antigen was more likely to be enterotoxigenic than strains possessing only the specific O antigen or H antigen or neither. Five E. coli strains belonging to undocumented enterotoxin-associated serotypes did contain a combination of previously reported enterotoxin-associated serotype O and H antigens and did produce enterotoxin.

Antigens, Bacterial↗