Evaluation of the roche AMPLICOR enterovirus PCR assay in the diagnosis of enteroviral central nervous system infections

BACKGROUND

Enteroviruses cause a substantial number of cases of aseptic meningitis annually in the USA. While culture has been useful in the detection of patients with viral meningitis it is time-consuming and lacks sensitivity. Detection of viral nucleic acid in patient specimens has been demonstrated to improve enteroviral detection.

OBJECTIVES

A research use only commercial amplification assay, the Roche AMPLICOR EV test, was compared to culture for the diagnosis of enteroviral meningoencephalitis.

STUDY DESIGN

Four-hundred and sixty-five consecutive CSF samples sent prospectively for suspicion of enteroviral infection were evaluated by PCR and shell-vial culture. Clinical information and CSF analysis were used to resolve PCR positive, culture negative samples. Sensitivity and specificity were calculated using resolved data.

RESULTS

There were 138 samples which met the definition of a true positive. Of these culture detected 77 (sensitivity 55.8%) and PCR detected 136 (sensitivity 98.6%). PCR missed two culture positive samples. Upon repeat testing, these CSF samples were found to contain inhibitors.

CONCLUSIONS

The Roche AMPLICOR EV-PCR test was statistically more sensitive than culture (P<0.001) in the detection of enteroviruses in CSF in patients suspected of having enteroviral meningitis. This assay also has the advantage of a rapid turnaround time of 5-6 h compared to 3-5 days for culture.

Bacillus cereus infections among oncology patients at a children's hospital

BACKGROUND

Bacillus cereus can cause severe infections in immunocompromised persons.

METHODS

We report 3 cases of bacteremia/septicemia (1 fatal) among oncology patients in a children's hospital. Because all cases occurred during a 10-day period, a common source outbreak was suspected. An epidemiologic investigation was performed. Molecular comparison of patient and environmental isolates was performed by using pulsed-field gel electrophoresis.

RESULTS

After an extensive investigation, no common hospital source could be found. Pulsed-field gel electrophoresis proved that the isolates were not related.

CONCLUSION

Sporadic infections in immunocompromised persons do occur and can be associated with significant morbidity.

Yersinia enterocolitis mimicking Crohn's disease in a toddler

A 31/2-year-old girl presented with persistent abdominal pain, fever, vomiting, and diarrhea accompanied by rash, oral ulceration, anemia, and an elevated sedimentation rate. Initial evaluation revealed no pathogens and was extended to include abdominal ultrasound and computed tomography showing marked ileocecal edema and mesenteric adenopathy. Colonoscopy revealed focal ulceration from rectum to cecum with histology of severe active colitis with mild chronic changes. Enteroclysis demonstrated a nodular, edematous terminal ileum. Because of the patient's clinical deterioration despite antibiotics, these features were construed consistent with Crohn's disease, and glucocorticoid therapy was begun. By the ninth hospital day, admission cultures grew Yersinia enterocolitica, and trimethoprim/sulfamethoxazole was begun followed by prompt clinical improvement. The delay in diagnosis afforded an unusually comprehensive clinical description of the presentation and diagnosis of Yersinia enterocolitis in childhood.

Investigation of a measles outbreak in a fully vaccinated school population including serum studies before and after revaccination

A measles outbreak in early 1989 among approximately 4200 students at a high school and two intermediate schools in suburban Houston, TX, was investigated to evaluate reasons for vaccine failure and to predict the efficacy of a booster dose of measles vaccine. Seventy-seven cases occurred (71 at the high school, 6 at intermediate schools; attack rate, 3.2 and 0.3%, respectively). Vaccination in the first year of life an 13 to 14 years since last vaccination were independent risk factors for being a case. Forty-three (18%) of 239 sera collected from students just before revaccination during the outbreak were negative by enzyme immunoassay; a neutralization assay confirmed these 43 lacked antibody predicting protection against measles infection. Of 43 enzyme immunoassay-negative students 24 gave another blood sample 9 to 10 months after revaccination. Revaccination appeared to reduce the portion of all students with neutralization titers predicting susceptibility to measles illness with rash from 7.9% to 3.0% and left the portion predicted to be susceptible to illness without rash unchanged (45%).