Diagnosis of Pneumocystis pneumonia by induced sputum technique in patients without the acquired immunodeficiency syndrome

Pneumocystis Pneumonia in Patients Treated With Long-Term Steroid Therapy for Symptom Palliation

We report 3 cases of pneumocystis pneumonia (PCP) in patients with advanced cancer who received palliative care. All patients received long-term steroid therapy for symptom management. A diagnosis of PCP was based on clinical symptoms and a positive Pneumocystis jiroveci polymerase chain reaction test from induced sputum specimens. Despite appropriate treatment, only 1 patient recovered from PCP. Long-term steroid, often prescribed in palliative care settings, is the most common risk factor for PCP in non-HIV patients. Pneumocystis pneumonia may cause distressing symptoms such as severe dyspnea, and the mortality rate is high. Therefore, it is important to consider PCP prophylaxis for high-risk patients and to diagnose PCP early and provide appropriate treatment to alleviate PCP-related symptoms and avert unnecessary shortening of a patient’s life expectancy.

Procedures for collection of induced sputum specimens from children

In most settings, sputum is not routinely collected for microbiological diagnosis from children with lower respiratory disease. To evaluate whether it is feasible and diagnostically useful to collect sputum in the Pneumonia Etiology Research for Child Health (PERCH) study, we reviewed the literature on induced sputum procedures. Protocols for induced sputum in children were collated from published reports and experts on respiratory disease and reviewed by an external advisory group for recommendation in the PERCH study. The advisory group compared 6 protocols: 4 followed a nebulization technique using hypertonic saline, and 2 followed a chest or abdomen massage technique. Grading systems for specimen quality were evaluated. Collecting sputum from children with lower respiratory tract illness is feasible and is performed around the world. An external advisory group recommended that sputum be collected from children hospitalized with severe and very severe pneumonia who participate in the PERCH study provided no contraindications exist. PERCH selected the nebulization technique using hypertonic saline.

Ineffectiveness of trimethoprim-sulfamethoxazole prophylaxis and the importance of bacterial and viral coinfections in African children with Pneumocystis carinii pneumonia

African human immunodeficiency virus type 1 (HIV-1)-infected children were evaluated to define the burden of Pneumocystis carinii pneumonia (PCP) and its interaction with bacterial and viral pathogens. P. carinii was identified in 101 (43.7%) of 231 episodes of pneumonia among 185 HIV-1-infected children (median age, 4.5 months; range, 1.7-27.3 months). Receipt of trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis was not associated with a significant reduction (36%; 95% confidence interval [CI], -15.4% to 64.5%) in isolation of P. carinii among children considered to have received adequate prophylaxis (37.7% of children) compared with children who had never received any prophylaxis (48.5% of children). However, deaths among children with PCP who had been taking TMP-SMX prophylaxis were markedly reduced (98.6%; 95% CI, 89.1%-99.8%) compared with children who were not taking prophylaxis. Concurrent P. carinii infection was observed in 6 of 18, 11 of 26, and 4 of 6 HIV-1-infected children who had bacteremia, a respiratory virus isolated, or Mycobacterium species isolated, respectively.

PCR detection of Pneumocystis carinii in bronchoalveolar lavage specimens: analysis of sensitivity and specificity

Although PCR detection of Pneumocystis carinii DNA has been described, little is known about the sensitivity or specificity of the assay in routine laboratory practice. We had the unique opportunity to use a bronchoalveolar lavage (BAL) specimen bank with samples for which the direct examination results for P. carinii were known. DNA purified from 129 selected specimens was amplified by using the primers described previously (A. E. Wakefield, F. J. Pixley, S. Banerji, K. Sinclair, R. F. Miller, E. R. Moton, and J. M. Hopkin, Mol. Biochem. Parasitol. 43:69-76, 1990). Of the 129 specimens, 37 were positive for P. carinii by direct examination. All 37 specimens were positive for P. carinii by PCR, yielding a 100% sensitivity and 100% negative predictive value for the assay. An additional 23 specimens were repeatedly positive for P. carinii by PCR but were not positive by direct examination. Review of the patient charts for these specimens with discordant results demonstrated that five of the patients were actually positive for P. carinii, as determined by either biopsy or examination of repeat or prior BAL specimens. A response to empiric therapy for P. carinii pneumonia was seen in an additional two patients. Of the remaining specimens, 8 produced no significant isolates other than P. carinii, while 12 contained culture-confirmed significant respiratory pathogens in addition to P. carinii (two fungal, nine bacterial, and one viral pathogen). Cytomegalovirus, which was of unknown significance, was isolated from 16 additional specimens. Overall, the specificity of the PCR assay was 79.3% compared to the results of direct examination. We hypothesized that the apparently poor specificity of the PCR assay was due to the increased sensitivity of the assay compared to that of direct examination. The sensitivity of the PCR assay was therefore assessed with BAL specimens containing P. carinii cysts. Serial dilutions of this preparation were evaluated by direct examination and PCR. PCR was found to be 100-fold more sensitive than direct examination, which detected one to two cysts per amplification. No false-positive results were detected in controls containing no DNA or by using target DNA from various fungal, viral, or bacterial respiratory pathogens. We conclude that PCR detection of P. carinii in BAL specimens is very sensitive and should be considered for patients whose specimens do not yield a diagnosis. The increased sensitivity of the PCR assay may help to identify those patients with low-titer infections who might benefit from directed antibiotic therapy for P. carinii and would otherwise be missed by direct examination alone.

New and unusual infections in neutropenic patients

Infections in immunocompromised patients with cancer are common and the primary risk factor is neutropenia, usually induced by chemotherapeutic agents. The spectrum of bacterial infection is shifting from gram-negative to gram-positive. The array of fungal infections in cancer patients is expanding to include organisms previously unknown as invasive human pathogens. New species are being defined to explain extant pathologies, and free living algae are now emerging as pathogens in immunocompromised patients. Physicians must remain alert to these emerging pathogens and to the need to evaluate optimal treatments for the usual and unusual infections in neutropenic and other compromised patients with cancer and allied diseases.

An assessment of sputum induction as an aid to diagnosis of respiratory infections in the immunocompromised child

Sputum induction using nebulised hypertonic saline was performed in two groups of immunocompromised children, one group with symptoms of respiratory infection and one group without. The asymptomatic group were bone marrow transplant (BMT) recipients, all seropositive for cytomegalovirus infection (CMV). Organisms were identified in three of 14 induced sputum specimens obtained from the symptomatic group (CMV N = 1, Haemophilus influenzae N = 2), but in none of 12 specimens from the asymptomatic group. Adverse effects encountered were minor. Four symptomatic patients with negative induced sputum samples underwent bronchoalveolar lavage, and no further organisms were identified. Sputum induction can be a useful adjunct to the diagnosis of respiratory pathogens in this group of patients.

Diagnostic approach to Pneumocystis carinii pneumonia in the setting of prophylactic aerosolized pentamidine

Recurrent Pneumocystis carinii pneumonia is common in patients with the acquired immunodeficiency syndrome who receive prophylaxis with aerosolized pentamidine. In this setting, the number of organisms is reduced and the clinical presentation may be altered. These observations have led to doubts regarding the use of induced sputum to diagnose PCP in patients receiving prophylactic AP. To determine if the examination of induced sputum is useful for patients receiving prophylactic AP, we examined our results over a 12-month period. We also examined several clinical criteria to ascertain if they could predict the likelihood of a positive induced sputum. As assessed by P(A-a)O2, need for admission and mortality, patients receiving AP presented with less severe disease than those not receiving AP. Twelve of 19 (63 percent) patients who developed PCP while receiving prophylactic AP were diagnosed by induced sputum. Induced sputum was positive for 35 of 55 (64 percent) patients who developed PCP and had not been receiving AP. However, there were no clinical characteristics which predicted a positive induced sputum. We conclude that induced sputum is an effective method for diagnosing PCP in patients receiving prophylactic AP.

Pneumocystis carinii pneumonia associated with profound lymphopenia and abnormal T-lymphocyte subset ratios during treatment for early-stage breast carcinoma

Two women with Stage II breast carcinoma treated with lumpectomy followed by breast irradiation and adjuvant chemotherapy developed Pneumocystis carinii pneumonia while receiving cytotoxic chemotherapy. Neither woman had evidence of immunosuppression before therapy. They both had profound lymphopenia, reversed CD4/CD8 ratios, and normal peripheral blood total leukocyte counts at the time of their infections. Both women were seronegative for human immunodeficiency virus type 1 and had no risk factors for such an infection. The patients' CD4 lymphocyte counts increased after chemotherapy for breast carcinoma was discontinued. Thus, it appears that the therapy they received may have caused severe T-lymphocyte mediated immunosuppression.

Opportunistic infections in children following renal transplantation

Opportunistic infections following renal transplantation in children are a major cause of severe morbidity and mortality. These infections account for the majority of early post renal-transplant deaths in children. General risk factors which affect the incidence and severity of these infections include: transmission of the infectious agent by the donor organ; history of immunity in the recipient prior to transplantation; type and amount of immunosuppression including treatment for rejection episodes; availability of specific treatment for the infection. Children are at particular risk because of the lack of exposure to certain pathogens prior to transplantation. There have been recent advances in the prevention and treatment of important infections which occur in children following transplantation, including varicella, Pneumocystis carinii pneumonia (PCP) and cytomegalovirus (CMV) disease. Varicella is treatable with acyclovir, often without decreasing immunosuppression and placing the graft at risk. Prophylaxis against PCP may be achieved by provision of alternate-day trimethoprim sulpha, but clear guidelines for determining who should be treated are lacking. Treatment of this disease with high-dose trimethoprim sulfa or pentamidine is usually successful. CMV disease is frequently severe, especially when the donor is seropositive and the recipient seronegative. In these situations, prophylactic CMV immunoglobulin reduces the morbidity and the mortality of the disease and prophylactic oral acyclovir may decrease its incidence. Treatment of severe CMV disease with gancyclovir is promising.