Etiology of childhood diarrhea in Beijing, China.

To determine the role of recently recognized enteropathogens in childhood diarrhea in China, 221 children with diarrhea and 108 controls seen at the Beijing Children's Hospital were studied during April and May 1989. Stools were examined for ova, parasites, and rotavirus, cultured for bacterial pathogens, and probed for enterotoxigenic Escherichia coli (ETEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. coli (EHEC), and enteropathogenic adherence factor-positive (EAF+) E. coli. Pathogens were identified in 56.5% of children with diarrhea and 43.5% of controls (P = 0.04). Detection of enteropathogens was significantly greater in patients examined within 1 week of symptom onset (65%) than in patients examined later (39%; P = 0.01). ETEC was the most frequently detected pathogen in children with diarrhea, accounting for 20% of the cases. Other agents identified in patients included the following: salmonellae, 12%; rotavirus, 7%; EIEC, 7%; EHEC, 7%; members of the Aeromonas hydrophila group, 6%; EAF+ E. coli, 5%; Ascaris lumbricoides, 3%; shigellae, 3%; campylobacters, 2%; and Vibrio spp., 0.5%. The isolation rates of salmonellae (P = 0.02), EAF+ E. coli (P = 0.04), and mixed pathogens (P = 0.05) were significantly greater for diarrhea patients than for controls. Resistance to multiple antimicrobial agents occurred in 39% of the Salmonella isolates, 22% of the Aeromonas isolates, and 17% of the Shigella isolates. Multiresistant salmonellae (P = 0.05) and shigellae were recovered from diarrheal stools only. Ciprofloxacin, cefotaxime, and imipenem were the only agents tested to which all bacterial isolates were susceptible in vitro. These results suggest that both traditional and newly recognized agents are important causes of childhood diarrhea in Beijing and that therapy may be complicated by indigenous antimicrobial resistance.

Arcanobacterium hemolyticum infection: confused with scarlet fever and diphtheria.

Arcanobacterium hemolyticum infections are a common cause of pharyngitis and rash in the 10- to 30-year-old age group. Despite its prevalence, many emergency and primary care physicians may not be aware of the pathogenic potential of this organism. We present a case that illustrates the distinctive clinical spectrum of A. hemolyticum infections that may be confused with drug allergy, group A streptococcal scarlet fever, diphtheria, and even toxic shock syndrome. Recognition of this syndrome will reduce misdiagnoses and facilitate appropriate treatment.

Laboratory diagnosis of Chlamydia trachomatis using two immunodiagnostic methods.

Seven hundred seventy-seven endocervical specimens collected from symptomatic and asymptomatic women in a low-prevalence population were examined for the presence of Chlamydia trachomatis by both enzyme immunoassay (EIA) and by direct immunofluorescence assay (DFA). Overall, 49 (6.2%) of specimens had positive results, however, only 26 had positive results by both assays. Concordant positivity was significantly higher in specimens from symptomatic women not taking antibiotics as compared with all other groups. Test discordance was not influenced by order of specimen collection, number of days of delay before the specimen was processed by EIA, cervical cytologic results, amount of mucopurulence, or presence of a particular bacterial species in simultaneously collected cervical swabs. The EIA optical density (OD) reading appeared to discriminate between the different test result groups more reliably than the number of elementary bodies seen on the DFA slide. Specimens with an OD reading greater than 0.300 and less than 0.060 can be interpreted with assurance as positive and negative, respectively. Caution may be necessary with specimens with intermediate values.

Chlamydia trachomitis antigen in the cervix: prevalence in a student population.

The prevalence of chlamydia trachomatis was investigated over a two-year period in a population of women university students attending a student health clinic for routine pelvic examination or for a gynecologic complaint. Direct immunofluorescence slide test was used to determine the presence of C. trachomatis. The overall prevalence rates for the two-years periods studied were 8.2% and 7.1%. When women who had symptoms of a urogenital infection were compared to women who were asymptomatic, it was found that symptomatic women were more likely to have C. trachomatis in the cervix. To determine whether women with positive cases showed differences in appearance of the cervix, method of contraception, or other organisms colonizing the vagina, the cases were matched with two controls, and a retrospective chart review was performed. The cases were more likely to have cervicitis and to be culture positive with gardnerella vaginalis, and they were less likely to have used condoms for contraception. In the two periods studied, the carriage rates for asymptomatic cases were 6% and 5%. Fifty-eight per cent of all positive cases were asymptomatic. If this organism is to be eradicated from college-women populations, all women attending for a urogenital infection should be screened, and women attending for routine annual examinations should be screened if there is a clinical indication.

Epidemiology and clinical features associated with Blastocystis hominis infection.

A retrospective chart review was performed on 100 patients infected with Blastocystis hominis (Bh) and 50 randomly selected age and sex matched controls to examine the clinical and epidemiologic features associated with this organism. The finding of greater than 5 Bh per oil immersion field (1,000 X) was significantly associated with acute presentation of symptoms but was not predictive of the presence of gastrointestinal symptoms. Of patients infected with Bh, 57.5% had recently travelled to the tropics or had consumed untreated water as compared to 12.2% of controls (p less than 0.001). Forty Bh-positive patients were assessed on more than one occasion. No significant differences appeared to exist in the clinical responses of those treated with Metronidazole (14/18; 77.8%) or with dietary management (6/6; 100%) as compared with those not receiving treatment (13/16:81.2%). Patients tended to become less symptomatic with time and in the absence of specific treatment, and therefore treatment with Metronidazole may not be warranted in light of the natural history of Bh infection.

Clinical significance of virulence-related assay of Yersinia species.

During the 42-month period from June 1982 through December 1985, 215 fecal specimens from 171 patients were found to be positive for yersiniae by using a combination of CIN agar and cold enrichment. Isolates were tested for markers of virulence including carriage of a plasmid 42 megadaltons in size, calcium dependence, autoagglutination, Congo red uptake, pyrazinamidase activity, fermentation of salicin, and hydrolysis of esculin. The results were correlated to symptoms in patients. A total of 80 Yersinia enterocolitica and 52 Y. enterocolitica-like strains (42 Y. frederiksenii, 8 Y. intermedia, and 2 Y. kristensenii) were examined. Positive virulence-related tests were as follows (for Y. enterocolitica, Y. frederiksenii, Y. intermedia, and Y. kristensenii, respectively): pyrazinamidase negativity, 12.5, 0, 0, and 50%; Congo red positivity, 5, 7.1, 87.5 and 0%; calcium dependence, 3.8, 0, 0, and 0%; autoagglutination positivity, 8.8, 0, 0, and 0%; carriage of the 42-megadalton plasmid, 28.6, 73.2, 5.7, and 0; salicin and esculin negativity, 12.5, 0, 0, and 50%. The isolates recovered from symptomatic patients were characterized in relation to the presenting symptoms. Isolates from 12 of 32 (37.5%) patients with acute-onset diarrhea and 9 of 30 (30.0%) patients with chronic symptoms expressed at least one virulence feature. No individual test or group of tests was consistently associated with onset or either type of symptoms. Routine testing of plasmid carriage, uptake of Congo red, calcium dependence, autoagglutination, and pyrazinamidase activity did not appear to provide information that would link the presence of symptoms with the virulence potential of fecal isolates of yersiniae.