Inappropriate treatment in children with bloody diarrhea: clinical and microbiological studies.

It is suggested that in dysentery physicians should treat empirically, as early treatment seems to improve outcome. A constantly updated knowledge of the relative frequency of enteropathogens and their sensitivity to antimicrobials is needed to choose the right therapy. We studied microbiological and clinical findings in 119 children with bloody diarrhea in Mexico City. Patients were divided into those < 1 year (infants) and those 1-5 years (children). Shigella was more frequent in children (35%) than in infants (10%). Campylobacter was more common in infants (29%) than in children (12%); Salmonella more frequent in infants (22%) than in children (8%); cytotoxic E. coli (EHEC) more frequent in children (20%) than in infants (13%). No cases of amebiasis were identified. Fever was the most sensitive indicator of infection for Shigella (70%), as compared for Salmonella (50%), Campylobacter (42%) and EHEC (36%); whereas specificity was about 50% for all pathogens. In contrast, the absence of fever was 80% predictive for the absence of these pathogens. In children with dysentery, the specific etiology cannot be predicted in the absence of culture. Almost 50% of the Shigella, Salmonella and EHEC isolates were resistant to ampicillin. In our community, the use of ampicillin and metronidazole should be discouraged.

Antisecretory activity in a lectin fraction of plasma from patients with acute diarrhea.

The present study describes the first attempt to detect antisecretory activity in a lectin fraction of plasma from patients with acute diarrhea. The plasma antisecretory protein (ASP) was purified by affinity chromatography in agarose, and its antisecretory activity tested in rats subjected to intestinal challenge with cholera toxin. During the first 24 h of the diarrheal episode, antisecretory activity in patients (median 0, range 0-25%) was lower than that seen in the asymptomatic group (median 10, range 0-30%); 3 days later, when diarrhea ceased in most of the patients, the ASP activity increased significantly (median 30, range 0-75%). However, 5 days later the activity decreased again (median 0, range 0-55%). No differences in ASP levels were found between cases associated with an enteropathogen and those where no pathogen was identified. These findings reveal an inverse relationship between the increase in ASP and the patient's intestinal secretion; suggesting that ASP plays a role in the compensatory mechanisms that occur in diarrhea in humans.

Frequency of identification of cytotoxigenic strains of Escherichia coli in cases of diarrhea from rural and urban communities.

It has been suggested that strains of Escherichia coli producing Vero-Toxin (VTEC) may cause diarrhea or hemorrhagic colitis; however, there are not enough studies to support this hypothesis. We studied the frequency of isolation of VTEC strains in patients with acute diarrhea from rural and urban communities. A total of 1430 strains were analyzed, 361 coming from 118 patients from the rural community (Cadereyta, Qro.) and 1069 from the urban district (D.F.); 95 of these patients were asymptomatic, 213 suffered from watery diarrhea and 43 had bloody diarrhea. For production of toxins, strains were grown in tryptic soy broth for 24h and the culture supernatant was inoculated on HeLa cells; strains were considered cytotoxic when they caused lysis in at least 50% of the cells. In the rural community, VTEC strains were isolated in 20% of the asymptomatics, in 45% of the watery diarrhea patients and in 76% of patients with bloody diarrhea. Frequency of isolation was significantly higher in patients with diarrhea than in asymptomatics (P less than 0.05). The relative risk to present watery diarrhea was 3 and to present bloody diarrhea was 12. In the urban district, VTEC strains were isolated in 13, 7.9 and 4.5% from asymptomatics, watery diarrhea and bloody diarrhea patients, respectively; the relative risk for diarrhea was 1. Colonization by VTEC strains is significantly higher in patients from the rural community and these infected patients have an important risk to develop diarrhea.

Detection of antibodies to Salmonella "O" antigens in typhoid fever by counterimmunoelectrophoresis. II. Assessment in patients with typhoid fever and in a healthy population.

Two different population groups were studied. In one, 50 patients with a confirmed diagnosis of typhoid fever. Serum determinations were made for the detection of antibodies to S. typhi somatic antigen using Widal technique, surface fixation test and counterimmunoelectrophoresis (CIE). In the other group, 350 healthy subjects were studied to determine the minimum diagnostic titer by means of CIE. It was possible to establish that a 1:16 titer was suggestive of typhoid fever when CIE techniques were used. Surface fixation test showed the highest sensitivity levels. CIE with sensitivity levels similar to those found in Widal's reaction exceeds the other test because of its standardization and greater reproducibility.