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L W Riley

Publications and source records attributed to L W Riley.

81 records · Page 5Linked to original sources
PubMed1984

Campylobacter infections in the United States. Results of an 11-state surveillance.

In January 1982, 11 states (Alabama, Arizona, Georgia, Illinois, Minnesota, New Mexico, Oregon, Texas, Vermont, Washington, and Wisconsin) began reporting monthly their isolations of Campylobacter to the Centers for Disease Control in Atlanta. The information reported included the species of Campylobacter organisms, the week of the report, the site from which the organism was isolated, and the age and sex of the infected person. A total of 3,966 isolates were reported in 1982, of which 3,900 were Campylobacter jejuni. Campylobacter isolations exceeded Salmonella in two of the three states (Oregon and Wisconsin) that require reporting. The eight other states with lower rates of isolation had variable reporting practices. Rates of Campylobacter isolations were highest in June through August. Age-specific rates of Campylobacter infections peaked in the 1- to 2-year and 20- to 29-year age groups. Fifty-five percent of all isolates were from male patients. Campylobacter infections seem to be at least as common as Salmonella infections in states in which the reporting practices are comparable.

Adolescent↗
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

Evaluation of isolated cases of salmonellosis by plasmid profile analysis: introduction and transmission of a bacterial clone by precooked roast beef.

In July-August 1981, the number of isolated cases of salmonellosis in New Jersey and Pennsylvania markedly increased. Concurrently, two outbreaks in these states caused by the same Salmonella serotypes were traced to a single brand of precooked roast beef. Plasmid profiles of outbreak and isolated strains were examined, and Salmonella newport isolates from the implicated meat and from cases in the two outbreaks were identified with a unique profile, present in 45% of reported strains from isolated cases in this area during the same period. Review of the food exposure histories in isolated cases demonstrated association between this plasmid profile and consumption of precooked roast beef (P = 0.003). Examination of S newport strains from other regions and intervals indicated that this strain was introduced into these two states sometime after March 1981. Thus, plasmid profile analysis was useful in studying the epidemiology of isolated cases of salmonellosis due to a sensitive common serotype.

Disease Outbreaks↗
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↗
PubMedDate not supplied

RFLP patterns and risk factors for recent tuberculosis transmission among hospitalized tuberculosis patients in Rio de Janeiro, Brazil.

Isolates of Mycobacterium tuberculosis from 120 tuberculosis patients seen in the 12 months ending September 1994 at 2 tertiary-care centres in Rio de Janeiro were characterized by IS6110 restriction fragment length polymorphism (RFLP) analysis. Ninety-seven patients (81%) had isolates with unique RFLP patterns, while 23 patients (19%) had isolates that belonged to 11 different RFLP cluster patterns. The strains from the latter patients were distributed among 1 group of 3 patients and 10 groups of 2 patients each. The cluster-pattern strains were not associated with gender, age, HIV infection, type of residence, living in shelter, homelessness or previous history of tuberculosis. However, clustering was strongly associated with multidrug resistance (P = 0.006). These data suggest that recent exogenous transmission may be important for the development of new cases of multidrug-resistant disease in patients attending tertiary-care centres in Rio de Janeiro, Brazil.

Adult↗
PubMedDate not supplied

Molecular epidemiology of tuberculosis in Prague: analysis by restriction fragment length polymorphism.

OBJECTIVES: To characterize by restriction fragment length polymorphism (RFLP) patterns, the distribution of different Mycobacterium tuberculosis strains isolated consecutively from 75 tuberculosis patients who resided in Prague and had culture-confirmed cases during a 4-month period in 1995. METHODS: The insertion sequence IS6110-based RFLP analysis of M. tuberculosis isolates was carried out. RESULTS: There were a total of 75 patients with various forms of tuberculosis (54 males; 21 females). The sources of M. tuberculosis isolates were sputum (n = 64), pleura or lymph node drainage (n = 8), and urine (n = 3). Fifty-three of the patients (70.7%) had isolates with unique RFLP patterns, while 22 (29.3%) had isolates that belonged to seven clusters of related RFLP patterns. The seven clusters consisted of four groups of two patients, two groups of four patients, and one group of six patients. Most of the patients whose isolates fell within a clustered RFLP pattern lived in different quarters of the city and had no identifiable contacts with other patients whose isolates had the same pattern. CONCLUSIONS: The finding that isolates from most patients (70.7%) had unique rather than clustered RFLP patterns suggests that endogenous reactivation rather than exogenous transmission is the major determinant of most of the tuberculosis cases in Prague. The occurrence of seven distinct clusters comprising 29.3% of the isolates suggests that approximately one third of cases developed active tuberculosis from recent exogenous transmission.

Adult↗
PubMedDate not supplied

Multiple isolates from aids patients: aspects of an analysis by a genotypic marker and antimicrobial susceptibilities variations.

Twenty-one Mycobacterium avium multisolates, from ten human immunodeficiency virus-infected patients, were typed by restriction fragment length polymorphism using as marker the IS1245 and characterized by minimum inhibitory concentration for nine different antibiotics. Two out of four patients harboring multisolates with different fingerprint profile, were therefore considered as having a polyclonal infection, since their isolates were taken from sterile site. This result confirms that polyclonal infection caused by M. avium occurs with a nonnegligenciable frequency. Analyzing the multisolates susceptibility profile of each patient it was observed that most of them were infected with strains having appreciably different antimicrobial susceptibility patterns, no matter what the genotypic pattern of the strains was. These results have strong implication for the treatment of the patients.

AIDS-Related Opportunistic Infections↗