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Biomedical subjects

O Grados

Publications and source records attributed to O Grados.

16 recordsLinked to original sources

Paediatric campylobacter diarrhoea from household exposure to live chickens in Lima, Peru.

Although Campylobacter jejuni is a frequent enteropathogen in cases of paediatric diarrhoea in developing countries, its route of transmission is not well understood. An age-matched, case-control study of children with C. jejuni diarrhoea was therefore carried out in Lima, Peru, from January 1983 to April 1986 to identify the risk factors and vehicles of transmissions. As cases, 104 children less than 3 years of age were selected and compared with controls of the same age with non-gastrointestinal illnesses. Household exposure to live chickens was an important risk factor (odds ratio, 11; after adjusting for socioeconomic and environmental variables). Subjects in index households had a higher frequency of infection than those in control households, and infected young children were more likely to be ill than older children or adults, suggesting that immunity may be acquired from natural infection. The risk factors identified suggest that direct contact with the faeces of C. jejuni-infected chickens in the household environment was largely responsible for transmission of the organism to susceptible infants.

Animals↗

Comparative in vitro activities of aztreonam, ciprofloxacin, norfloxacin, ofloxacin, HR 810 (a new cephalosporin), RU28965 (a new macrolide), and other agents against enteropathogens.

The in vitro activity of drugs currently used in the treatment of diarrhea against 595 enteropathogens from worldwide sources was compared with that of six newly developed antibiotics, ciprofloxacin; norfloxacin; ofloxacin; aztreonam; HR810, an expanded-spectrum cephalosporin; and RU28965, a new macrolide. In contrast with ampicillin and chloramphenicol, trimethoprim-sulfamethoxazole showed an excellent activity against all of the enteropathogens tested, except Campylobacter species. Ciprofloxacin had the highest activity, with an overall 90% MIC of less than or equal to 0.097 micrograms/ml, except for Campylobacter species (0.39 micrograms/ml). Unlike other cephalosporins, HR810 showed a satisfactory activity against Campylobacter species (90% MIC of 3.12 micrograms/ml). RU28965 was three times less active than erythromycin against Campylobacter species.

Anti-Bacterial Agents↗

Diagnosis of typhoid fever using a string capsule device.

Cultures were made from blood, bone marrow, stool and duodenal contents (obtained with string capsules) from 36 patients with bacteriologically proven typhoid fever on admission to hospital. Duodenal content cultures proved to be as sensitive in diagnosis (86%) as bone marrow (75%) and more effective than blood (42%) and stool (26%) cultures in recovery of Salmonella typhi. The sensitivity of duodenal content cultures was not modified by the duration of illness at admission or by previous antibacterial therapy. Even on the seventh day of effective treatment with chloramphenicol, the culture of duodenal contents remained positive in 8 of 17 patients, whereas salmonellae were isolated from stool cultures in only 2 of the same patients. The results obtained with the string capsule, together with the simplicity, economy and acceptability of the procedure, the fact that it can be performed with minimal facilities and the advantages of bacteriological recovery for antibiotic sensitivity testing, suggest that its adoption would be very helpful in efforts to control this disease.

Bacteriological Techniques↗

In-vitro susceptibility of salmonellae to antimicrobial agents.

The minimum inhibitory concentrations (MIC) of various antimicrobial drugs, for 667 strains of Salmonella, isolated in three different continents of the world, were determined: 17 antibiotics were tested against 506 randomly selected and 161 chloramphenicol-resistant strains. The activity of the monobactam aztreonam against these organisms was in general equal or superior to that observed with the third-generation cephalosporins, cefotaxime and ceftazidime. Furthermore aztreonam and cefotaxime exhibited uniform and high activity against all the salmonella strains tested, irrespective of their chloramphenicol resistance. Ceftazidime was found to have higher geometric mean MICs only for non-typhi salmonellae from Peru.

Aminoglycosides↗

Thermolabile antigens of "Salmonella typhi".

Somatic soluble antigens of S. typhi can be subdivided into three categories. These are: 1. Thermolabile antigens (TL) at 100 degrees C or 121 degrees C. They showed two kind of fractions, by immunoelectrophoresis method, some anodic and others cathodic in migration. 2. Thermostable haptens (Th) at 100 degrees C or 121 degrees C. Demonstrated by their capacity to absorb antibodies after heat treatment (100 degrees C or 121 degrees C) and to precipitate antibodies from antiserum produced with unheated bacterial suspensions. These fractions failed to induce antibody production, after heating in rabbits. Electrophoretically they migrated toward the anode. 3. Thermostable antigens (TS) at 100 degrees C or 121 degrees C. Demonstrated by their capacity to induce antibody formation in rabbits after heat treatment at 100 degrees C or 121 degrees C and to precipitate antibodies after being heated at these temperatures. These antigens revealed only cathodic migration. Using the serum made with S. typhi strain Ty-21a, thermolabile and thermostable antigens were demonstrated in S. typhi 0901 strain.

Antigens, Bacterial↗

Diagnostic value of the Widal test in areas endemic for typhoid fever.

The usefulness of a single Widal test to diagnose typhoid fever in endemic areas was investigated. Reciprocal Salmonella typhi O and H titers greater than or equal to 40 and greater than or equal to 80, respectively, occurred in approximately 90% of 42 Mexican patients with bacteriologically-confirmed typhoid fever at the time of presentation to hospital and, by day 4 to 5 of clinical illness, in 70% of U.S. adult volunteers who developed typhoid fever in the course of vaccine efficacy trials but in only 0.7% (O) to 3% (H) of 275 healthy individuals from a non-endemic area. Healthy Peruvians from areas endemic for typhoid fever commonly had antibody which was age-related. Peak prevalence was found in 15- to 19-yr-olds in whom 29% had O titers greater than or equal to 40 and 76% had H titers greater than or equal to 80. A single Widal test in an unvaccinated individual showing elevated O and H titers is strongly suggestive of typhoid fever if the person comes from a non-endemic area or is a child less than 10 yr of age in an endemic area. Because of the high prevalence of antibody amongst healthy invididuals over 10 yr of age in endemic, areas, a single Widal test offers virtually no diagnostic assistance in adolescents and adults.

Adolescent↗