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2.
N Engl J Med ; 331(9): 579-84, 1994 Sep 01.
Article in English | MEDLINE | ID: mdl-8047082

ABSTRACT

BACKGROUND: In the summer of 1991, simultaneous outbreaks of bloody diarrhea and hemolytic-uremic syndrome caused by Escherichia coli O157:H7 and of bloody diarrhea caused by Shigella sonnei were traced to a lakeside park near Portland, Oregon. METHODS: We identified cases primarily from routine surveillance reports. In case-control studies, the activities of persons with park-associated E. coli O157:H7 or S. sonnei infections were compared independently with those of three sets of controls. We also evaluated environmental conditions at the park and subtyped the bacterial isolates. RESULTS: We identified 21 persons with park-associated E. coli O157:H7 infections (all of them children; median age, six years) and 38 persons with S. sonnei infections (most of them children). These 59 people had visited the park over a 24-day period. Their illnesses were not associated with food or beverage consumption. All the case patients reported swimming, however, and in case-control studies swimming was strongly associated with both types of infection (P = 0.015 or less). The case patients were more likely than the controls to report having swallowed lake water, and they had spent more time in the lake. Numbers of enterococci indicative of substantial fecal contamination (geometric mean, > 50 per deciliter) were detected in the swimming area during some but not all of the outbreak period. Park-associated E. coli O157:H7 isolates were identical by pulsed-field gel electrophoresis and were distinguishable from other isolates in the Portland area. CONCLUSIONS: Lake water that was fecally contaminated by bathers was the most likely vehicle for the transmission of both the E. coli O157:H7 and the S. sonnei infections. The unusually prolonged outbreak suggests both the survival of these enteric organisms in lake water and a low infectious dose.


Subject(s)
Colitis/epidemiology , Disease Outbreaks , Dysentery, Bacillary/epidemiology , Escherichia coli Infections/epidemiology , Gastrointestinal Hemorrhage/epidemiology , Shigella sonnei , Case-Control Studies , Child , Colitis/microbiology , Dysentery, Bacillary/microbiology , Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Feces/microbiology , Gastrointestinal Hemorrhage/microbiology , Humans , Oregon/epidemiology , Shigella sonnei/isolation & purification , Swimming , Water Microbiology
3.
Biochemistry ; 31(32): 7311-9, 1992 Aug 18.
Article in English | MEDLINE | ID: mdl-1380823

ABSTRACT

The gramicidin K family is a set of naturally occurring acylated linear peptides in which a fatty acid is esterified to the ethanolamine hydroxyl of either gramicidin A or C, and possibly also to gramicidin B (Koeppe, R. E., II, Paczkowski, J. A., & Whaley, W. L. (1985) Biochemistry 24, 2822-2826). These acylated gramicidins form membrane-spanning channels in planar lipid bilayers and therefore constitute a model system with which to study the structural and functional consequences of acylation on membrane proteins. This paper serves to characterize further the channels formed by acylated gramicidins A and C and to demonstrate that these channels are structurally equivalent to the channels formed by the standard gramicidins. We also present additional evidence for the ester linkage in the natural acylated gramicidins A and C and identify the fatty acyl chains.


Subject(s)
Gramicidin/chemistry , Ion Channels/physiology , Models, Biological , Acylation , Amino Acid Sequence , Electric Conductivity , Kinetics , Magnetic Resonance Spectroscopy/methods , Mass Spectrometry , Molecular Sequence Data , Protein Conformation , Thermodynamics
5.
Biophys J ; 58(5): 1207-12, 1990 Nov.
Article in English | MEDLINE | ID: mdl-1705449

ABSTRACT

The membrane structure of the naturally occurring gramicidins A, B, and C was investigated using circular dichroism (CD) spectroscopy and single-channel recording techniques. All three gramicidins form channels with fairly similar properties (Bamberg, E., K. Noda, E. Gross, and P. Läuger. 1976. Biochim. Biophys. Acta. 419:223-228.). When incorporated into lysophosphatidylcholine micelles, however, the CD spectrum of gramicidin B is different from that of gramicidin A or C (cf. Prasad, K. U., T. L. Trapane, D. Busath, G. Szabo, and D. W. Urry. 1983. Int. J. Pept. Protein Res. 22:341-347.). The structural identity of the channels formed by gramicidin B has, therefore, been uncertain. We find that when gramicidins A and B are incorporated into dipalmitoylphosphatidylcholine vesicles, their CD spectra are fairly similar, suggesting that the two channel structures could be similar. In planar bilayers, gramicidins A, B, and C all form hybrid channels with each other. The properties of the hybrid channels are intermediate to those of the symmetric channels, and the appearance rates of the hybrid channels (relative to the symmetric channels) corresponds to what would be predicted if all three gramicidin molecules were to form structurally equivalent channels. These results allow us to interpret the different behavior of channels formed by the three gramicidins solely on the basis of the amino acid substitution at position 11.


Subject(s)
Gramicidin/chemistry , Ion Channels/chemistry , 1,2-Dipalmitoylphosphatidylcholine , Amino Acid Sequence , Biophysical Phenomena , Biophysics , Circular Dichroism , Lipid Bilayers , Lysophosphatidylcholines , Molecular Sequence Data , Molecular Structure
6.
JAMA ; 264(2): 213-7, 1990 Jul 11.
Article in English | MEDLINE | ID: mdl-2355442

ABSTRACT

Although eosinophilia-myalgia syndrome has been linked to use of tryptophan, it has been unclear whether tryptophan itself or a contaminant causes illness. In Oregon, we compared the brand and source of tryptophan used by 58 patients with eosinophilia-myalgia syndrome with the brand and source of tryptophan used by 30 asymptomatic controls identified through a random telephone survey and 63 asymptomatic controls who contacted the Oregon Health Division voluntarily. Although a single brand/retail lot of tryptophan was statistically associated with the development of eosinophilia-myalgia syndrome, there was no common importer, wholesaler, tablet maker, encapsulator, or distributor. However, 45 (98%) of 46 cases had taken a product made by one manufacturer, compared with three (30%) of 10 telephone survey controls and 15 (48%) of 31 volunteer controls. Retail lots of tryptophan from this manufacturer that were associated with cases were significantly more likely to have been produced from January through June 1989 than lots from this manufacturer that were taken by controls. These findings indicate that the recent epidemic of eosinophilia-myalgia syndrome was caused by a contaminant or an alteration in a subset of tryptophan manufactured by a single company in Japan shortly before the outbreak began.


Subject(s)
Drug Contamination , Eosinophilia/chemically induced , Muscles , Pain/chemically induced , Tryptophan/adverse effects , Adult , Aged , Case-Control Studies , Disease Outbreaks , Drug Industry , Eosinophilia/epidemiology , Female , Humans , Japan , Male , Middle Aged , Pain/epidemiology , Regression Analysis , Syndrome , United States/epidemiology
9.
10.
Am J Public Health ; 77(11): 1431-4, 1987 Nov.
Article in English | MEDLINE | ID: mdl-3661796

ABSTRACT

The largest reported United States outbreak of illness caused by a foodborne pesticide was due to aldicarb-contaminated watermelons. In Oregon, where the first episodes of toxicity were reported, 264 reports were received, and 61 definite cases were identified. Residues of aldicarb, a cholinesterase inhibitor, were found in 10 of 16 tested melons which had been eaten by persons meeting the case definition. The outbreak demonstrates the need for enhanced physician vigilance with respect to anticholinesterase intoxication. It also demonstrates the value of an established system for reporting of unusual illness to public health officials.


Subject(s)
Aldicarb/poisoning , Disease Outbreaks , Fruit/poisoning , Gastrointestinal Diseases/chemically induced , Insecticides/poisoning , Pesticide Residues/analysis , Aldicarb/analysis , Female , Fruit/analysis , Gastrointestinal Diseases/epidemiology , Humans , Male , Middle Aged , Oregon
11.
JAMA ; 257(1): 43-6, 1987 Jan 02.
Article in English | MEDLINE | ID: mdl-2431167

ABSTRACT

After a retreat to an Oregon farm, 19 of 31 college students developed an acute gastrointestinal illness. Campylobacter jejuni infection was recognized in all the ill students and caused asymptomatic infections in three others. In total, 22 (88%) of 25 students who consumed raw milk for the first time became infected as compared with none of two who had not consumed raw milk. Among ten persons who chronically consumed raw milk, none was ill, a striking difference from the 76% attack rate among the 25 acutely exposed students. The quantity of raw milk consumed was directly related to the occurrence and severity of illness. Acutely infected students showed significant rises in C jejuni-specific immunoglobulins, whereas the low antibody levels seen in unexposed persons did not rise. In contrast, acute-phase serum samples from persons with chronic exposure to raw milk showed elevated antibody levels to C jejuni. These findings indicate that chronic raw milk consumption is associated with elevated levels of C jejuni-specific serum antibodies and with immunity to symptomatic infection.


Subject(s)
Antibodies, Bacterial/biosynthesis , Campylobacter Infections/immunology , Campylobacter fetus/immunology , Disease Outbreaks , Enteritis/immunology , Milk/immunology , Acute Disease , Acute-Phase Proteins/blood , Adolescent , Adult , Animals , Campylobacter Infections/epidemiology , Campylobacter Infections/etiology , Cattle , Enteritis/epidemiology , Enteritis/etiology , Food Microbiology , Humans , Immunity, Active , Milk/microbiology
12.
Diagn Microbiol Infect Dis ; 2(2): 119-28, 1984 Apr.
Article in English | MEDLINE | ID: mdl-6713808

ABSTRACT

During a 3-month period in the late summer and fall of 1981, six cases of gastroenteritis and one wound infection due to Vibrio parahaemolyticus were reported to public health agencies in Washington and Oregon. An investigation revealed that all of the gastroenteric illnesses were associated with eating raw oysters; that oysters eaten by five of the six patients were harvested at four divergent sites at Willapa Bay, Washington, a large commercial growing area; and that the V. parahaemolyticus isolates from those five patients were all Kanagawa positive, belonged to serotype 04:K12, and exhibited an atypical biochemical reaction, urea hydrolysis. No further cases linked to Willapa Bay oysters have been reported, and the infecting strain could not be found in sediment samples from the bay in February 1982. Thus, even though the origin of this self-limiting outbreak is obscure, the investigation demonstrated that the geographic distribution of V. parahaemolyticus infection in the United States includes the Pacific seacoast . Furthermore, oysters must be considered, along with crabs, shrimp, and lobster, as a vehicle of transmission of this infection in the United States.


Subject(s)
Gastroenteritis/etiology , Shellfish Poisoning , Vibrio Infections/etiology , Adult , Epidemiologic Methods , Female , Humans , Male , Middle Aged , Ostreidae/microbiology , Vibrio parahaemolyticus , Washington , Wound Infection/etiology
13.
Am J Public Health ; 74(4): 370-2, 1984 Apr.
Article in English | MEDLINE | ID: mdl-6367499

ABSTRACT

In October 1978 in Boise, Idaho, a woman died of rabies after receiving a corneal transplant from a man, who in retrospect was also found to have died of rabies. Investigation of 203 contacts of these two patients identified 94 who were felt to have had sufficient risk of exposure to justify being given rabies post-exposure prophylaxis. Nurses, physicians, respiratory therapists, and family members were at greatest risk. We discuss the problems encountered in determining risk of exposure for contacts of humans with rabies.


Subject(s)
Cross Infection/transmission , Rabies/transmission , Adolescent , Adult , Aged , Child , Child, Preschool , Corneal Transplantation , Female , Humans , Idaho , Infant , Male , Middle Aged , Rabies/prevention & control , Rabies Vaccines/therapeutic use , Risk , Time Factors
14.
Hist Teacher ; 13(3): 379-83, 1980.
Article in English | MEDLINE | ID: mdl-11614619
16.
Poult Sci ; 55(5): 1848-57, 1976 Sep.
Article in English | MEDLINE | ID: mdl-792856

ABSTRACT

Procedures are described for determining the effects of low level antibiotic feed additives in broiler chick rations when chicks are artificially infected with Salmonella typhimurium var. copenhagen and the effectiveness of the same antibiotics used therapeutically for salmonellosis. These procedures also permit study of development of antibiotic resistant enteric flora related to antibiotic feeding and the transferability of the resistance. Measures should be taken to monitor and assure minimal extraneous bacterial contamination of eggs, chicks, feed and facilities and minimize baseline antibiotics resistance. Facilities and equipment should be fumigated extensively, chicks should be from primary breeder flocks off antibiotics for two generations, handled minimally, and fed all-vegetable protein rations. Optimum procedures for oral induction of salmonellosis with a chick-virulent strain of Salmonella typhimurium var. copenhagen are reported. Effects of low level antibiotic feeding and subsequent therapeutic level feeding of infected and control birds are measured by mortality, feed efficiency and weight gain, and microbiological analyses of fecal samples, intestinal samples and necropsied dead chicks. Gathering all data possible from all facets of the trials is imperative for ascertaining antibiotic effects.


Subject(s)
Animal Feed , Anti-Bacterial Agents/administration & dosage , Chickens , Food Additives , Poultry Diseases/drug therapy , Salmonella Infections, Animal/drug therapy , Animals , Anti-Bacterial Agents/therapeutic use , Escherichia coli/isolation & purification , Feces/microbiology , Intestines/microbiology , Poultry Diseases/microbiology , R Factors , Salmonella/isolation & purification , Salmonella Infections, Animal/microbiology , Salmonella typhimurium/isolation & purification
17.
Infect Immun ; 13(3): 1005-7, 1976 Mar.
Article in English | MEDLINE | ID: mdl-773819

ABSTRACT

Escherichia coli K-12 strains with and without an Ent plasmid were fed to calves, and the survival of each was monitored by viable bacterial counts of the feces. The E. coli K-12 strain carrying the Ent plasmid survived in the calves at significantly higher levels and for a longer period of time than the E. coli F(-) stain.


Subject(s)
Escherichia coli/pathogenicity , Extrachromosomal Inheritance , Plasmids , Animals , Cattle , Cell Survival
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