Ted A. Pearson

Successful Medical Therapy for Deeply Invasive Facial Infection Due to Pythium insidiosum in a Child

Pythiosis occurs in animals and humans who encounter aquatic habitats that harbor Pythium insidiosum. Drug therapy for deeply invasive infections with this organism has been ineffective in humans and animals; patients have been cured only by radical surgical debridement. A 2-year-old boy developed periorbital cellulitis unresponsive to antibiotic and antifungal therapy. The cellulitis extended to the nasopharynx, compromising the airway and necessitating a gastrostomy for feeding. P. insidiosum was isolated from surgical biopsy specimens of the affected tissue. On the basis of in vitro susceptibility studies of the isolate, the patient was treated with a combination of terbinafine and itraconazole. The infection resolved over a period of a few months. The patient remained well 1.5 years after completing a 1-year course of therapy. Cure of deep P. insidiosum infection is feasible with drug therapy.

Bacillus cereus Bacteremia and Meningitis in Immunocompromised Children

Two cases of Bacillus cereus meningitis in immunocompromised children at our hospital within a 2-month period prompted us to review B. cereus--related invasive disease. We identified 12 patients with B. cereus isolated in blood cultures from September 1988 through August 2000 at our institution. Three of these patients also had B. cereus isolated from CSF specimens; 1 additional patient had possible CNS involvement (33%, group A), whereas 8 patients had no evidence of CNS involvement (67%, group B). Patients in group A were more likely to have neutropenia at the onset of sepsis and were more likely to have an unfavorable outcome. They were also more likely to have received intrathecal chemotherapy in the week before the onset of their illness. Two patients from group A died. One survived with severe sequelae. The fourth patient had mild sequelae at follow-up. No sequelae or deaths occurred among patients in group B. In patients with unfavorable outcomes, the interval from the time of recognition of illness to irreversible damage or death was short, which demonstrates a need for increased awareness, early diagnosis, and more-effective therapy, particularly that which addresses B. cereus toxins.

Fatal Bacillus Cereus Pneumonia and Sepsis in a Child with Cancer

From the Infectious Diseases Service, St. Jude Children’s Research Hospital and the Laboratory of Clinical Bacteriology. Supported by General Research Support Grant RR05584, and Childhood Cancer Research Center Grant CA-08480, National Cancer Institute, from the National Institutes of Health and by ALSAC. * Correspondence to Sandor Feldman, M.D., Infectious Diseases Service, St. Jude Children’s Research Hospital, 332 North Lauderdale, P.O. Box 318, Memphis, Tenn. 38101. PECIES of the Bacillus genus are motile, gram-positive, aerobic, spore-forming rods found widely in air, soil, water, milk, and feces.’ Except for the highly virulent Bccccillrcs anthracis, members of this genus are generally considered saprophytes or laboratory contaminants when isolated from clinical specimens. At times, however, Bacillus cereus has been implicated as the etiologic agent in pneumonia, 2.3 purulent pleuritis,~ ophthalmitis,’ food poisoning,6>7 meningitis,’ and bacteremia as a complication of hemodialysis.9 One case of fatal B. cereus pneumonia has been reported in a cancer patient.~ 2

Mycotic cervical lymphadenitis following oral mucositis in children with leukemia

Four children developed mycotic cervical lymphadenitis while receiving cytotoxic chemotherapy for acute leukemia. Neutropenia, oral mucositis, and broad-spectrum antibiotic administration preceded the appearance of lymphadenitis in each case. Enlarged tender cervical lymph nodes of mycotic origin were not clinically distinguishable from lymphadenitis of bacterial or viral origin. Although cervical lymphadenitis was the initial clinical manifestation of deep fungal infection, computerized tomography of the chest and abdomen subsequently demonstrated asymptomatic pulmonic, splenic, or hepatic lesions characteristic of fungal abscesses in all four children. These findings demonstrate the importance of microbiologic identification of the etiologic agents of cervical lymphadenitis following mucositis and neutropenia in children with leukemia.

An Investigation of the Safety of the Blood Reinfusion Step Used With Tunneled Venous Access Devices in Children With Cancer

Infection has been identified as the most serious potential complication of the indwelling catheter. As a result, the primary nursing goal using the catheters is to prevent infection. Nurses must frequently manipulate the catheters when securing blood specimens and are concerned that this manipulation may serve as a source of infection for the immunocompromised pediatric oncology patient. One particular step in catheter manipulation during blood sampling is blood reinfusion, ie, residual blood in the catheter is withdrawn and set aside while a second sample is collected for laboratory analysis but is subsequently returned to the patient through the catheter. The purpose of this study was to examine this nursing procedure for its potential of contaminating the blood sample that was to be reinfused, or for the potential of reinfusing a sample that contained preexisting pathogens independent of the procedure itself. An experimental design was used with 21 patients randomly assigned to an experimental group (unclean procedure to exaggerate the potential to incur pathogens during the process), and 21 randomly assigned to a control group (usual clean procedure followed with the reinfusion sample). The usual blood sampling procedure was altered for all participants as the typical amount of blood that normally constitutes the reinsertion sample was not reinserted, but was instead used to complete certain microbial analyses. Of the 42 participants, 17 were male and 25 were female; 35 were white and seven were black; 22 were diagnosed with leukemias and 20 with solid tumors. The age range for participants was 2 to 20 years (x = 9.4 years, SD = 4.8). The two groups of participants did not differ for age, diagnosis, phase in treatment, hematologic indicators, or other demographic variables. No colony-forming units were noted in any of the collected samples for either of the two groups. The study findings may be interpreted as an indication that the current institutional procedure for collecting blood samples, when carefully followed, is not serving as a potential source of infection for nonneutropenic pediatric oncology patients.

Fungal susceptibility testing.

The utility of antifungal susceptibility testing has not been broadly determined. Thus, susceptibility testing of fungal isolates is not recommended on a routine basis. For instance, susceptibilty testing may be considered for some Candida species and for patients with Pseudallescheria boydii infections. Testing of yeasts for susceptiblity to azoles is of particular value due to their variability in response to these agents. It may also be important to test the susceptibility of new fungal organisms not previously identified or known to cause human disease because in these situations there are no clinical reports of efficacy to guide the choice of antifungal therapy.