Evaluation of calcofluor white stain for detection of Pneumocystis carinii

Evaluation of PCR in bronchoalveolar lavage fluid for diagnosis of Pneumocystis jirovecii pneumonia: a bivariate meta-analysis and systematic review

BACKGROUND

As a promising tool, PCR in bronchoalveolar lavage fluid (BALF) has not been accepted as a diagnostic criterion for PJP.

OBJECTIVE

We undertook a systematic review of published studies to evaluate the diagnostic accuracy of PCR assays in BALF for PJP.

METHODS

Eligible studies from PubMed, Embase and Web of Science reporting PCR assays in BALF for diagnosing PJP were identified. A bivariate meta-analysis of the method's sensitivity, specificity, and positive and negative likelihood ratios with a 95% confidence interval (CI) were analyzed. The post-test probability was performed to evaluate clinical usefulness. A summary receiver operating characteristics (SROC) curve was used to evaluate overall performance. Subgroup analyses were carried out to analysis the potential heterogeneity.

RESULTS

Sixteen studies published between 1994 and 2012 were included. The summary sensitivity and specificity values (95% CI) of PCR in BALF for diagnosis of PJP were 98.3% (91.3%-99.7%) and 91.0% (82.7%-95.5%), respectively. The positive and negative likelihood ratios were 10.894 (5.569-21.309) and 0.018 (0.003-0.099), respectively. In a setting of 20% prevalence of PJP, the probability of PJP would be over 3-fold if the BALF-PCR test was positive, and the probability of PJP would be less than 0.5% if it was negative. The area under the SROC curve was 0.98 (0.97-0.99).

CONCLUSIONS

The method of PCR in BALF shows high sensitivity and good specificity for the diagnosis of PJP. However, clinical practice for the diagnosis of PJP should consider the consistent respiratory symptoms, radiographic changes and laboratory findings of the suspected patients.

Successful treatment of periodontal mucormycosis: report of a case and literature review

Mucormycosis is an aggressive and potentially devastating fungal infection which typically manifests in pulmonary, rhinocerebral, or disseminated forms in patients with hematologic malignancy. Mucormycosis confined to the periodontium is uncommon, and to our knowledge only 6 cases have been reported in the English-language literature. This case report describes a patient with acute leukemia and periodontal mucormycosis. Calcofluor fluorescence microscopy is also proposed as a method for establishing a prompt diagnosis and guiding extent of intraoperative surgical debridement.

FlindersTechnology Associates (FTA) filter paper-based DNA extraction with polymerase chain reaction (PCR) for detection of Pneumocystis jirovecii from respiratory specimens of immunocompromised patients

We evaluated the diagnostic value of Flinders Technology Associates (FTA) filter paper together with polymerase chain reaction (PCR) for detection of Pneumocystis jirovecii (carinii) from induced sputum (IS) and bronchoalveolar lavage fluid (BALF) samples. The study involved 162 patients with clinical diagnosis of pneumocystis pneumonia (PcP) of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) patients and other immunocompromised patients. P. jirovecii cysts or trophozoites were detected in IS and BALF by cytological method. The mitochondrial 5S ribosomal ribonucleic acid (rRNA) gene of P. jirovecii was amplified from these samples by using FTA filters together with a one-step PCR method (FTA-PCR). With the FTA-PCR method, the sensitivity and specificity of the test compared to microscopic examination were 67% and 90% for IS, while they were 67% and 91% for BALF, respectively. The sensitivity and specificity of the FTA-PCR test was also comparable to PCR with the conventional deoxyribonucleic acid (DNA) extraction method. We concluded that FTA-PCR is useful to detect P. jirovecii in noninvasive IS.

Pneumocystis jiroveci Pneumonia

Pneumocystis pneumonia (PCP) is one of the most common pulmonary infections in persons with impaired cell-mediated immunity, and particularly those infected with human immunodeficiency virus (HIV).1–7 Pneumocystis was first described in the lungs of guinea pigs, during experiments on American trypanosomiasis by Carlos Chagas8 in 1909 and by Antonio Carinii9 in 1910. Both considered the cysts of Pneumocystis as part of the trypanosome’s life cycle. Shortly afterward the Delanoes10 found identical forms in the lungs of rats that had not been infected with trypanosomes and recognized the organism as a separate species. The name Pneumocystis carinii, was given to this organism as a generic name (Greek:pneumon, “lung”; kystis, “cyst”), honoring Carinii.11

The lung in the immunocompromised patient. Infectious complications Part 1

Pulmonary infections are a major cause of morbidity and mortality in the immunosuppressed patient. Among the infections encountered are Pneumocystis carinii, mycobacterial, fungal, and bacterial infection. In this review, we will discuss these various possible infections, their frequency of occurrence, and their clinical presentation in the various immunosuppressed groups.

Laboratory diagnosis of Pneumocystis carinii infections by PCR directed to genes encoding for mitochondrial 5S and 28S ribosomal RNA

PCR with 5S mitochondrial ribosomal RNA (5S) target is a sensitive and specific assay for the detection of Pneumocystis carinii in clinical specimens from the respiratory tract. We developed an oligonucleotide probe directed to a 200 bp amplicon generated by fungal-specific universal primers that anneals with sequences specific for P. carinii in the 28S ribosomal RNA gene (28S). Of 50 archived bronchoalveolar lavage 1(BAL) specimens, 46 of 50 samples (92% agreement) gave the same result (23 positive, 23 negative) by PCR directed to the 5S and 28S assays. Results of calcofluor white staining of BAL smears on slides indicated agreement with the molecular results in 43 of 46 (93.5%) assays. PCR detection of P. carinii by amplification of 28S ribosomal gene target by fungal-specific primers and an organism-specific probe provides an alternate genomic target for the laboratory diagnosis of this organism.

Rapid diagnosis of acute eosinophilic pneumonia (AEP) in a patient with respiratory failure using bronchoalveolar lavage (BAL) with calcofluor white (CW) staining

A diagnosis of exclusion, acute eosinophilic pneumonia (AEP) is an acute febrile illness with respiratory impairment, diffuse pulmonary infiltrates, and bronchoalveolar lavage (BAL) fluid eosinophilia. Whether pulmonary eosinophilia in AEP is primary or secondary remains undetermined. We report here a 22-year-old auto mechanic with severe AEP and acute respiratory failure who required intubation and ventilatory support. The patient's bronchoalveolar lavage (BAL) fluid was analyzed using cultures, cytology, Wright/Giemsa, Gram, Gomori-methenamine-silver (GMS), and calcofluor white (CW) stains (1). Despite extensive evaluation, no infectious etiology was found. CW staining helped us rapidly to exclude Pneumocystis carinii or fungal infection and to focus attention toward the diagnosis of AEP. Transbronchial biopsy was unnecessary and supportive therapy without systemic glucocorticoids was followed by recovery within a few weeks. In this case, bronchoalveolar lavage with CW staining was of great assistance in the rapid diagnosis and initial management of AEP. Our literature review found no prior article using CW staining for evaluation of AEP.

Pneumocystis carinii pneumonia: the status of Pneumocystis biochemistry

Pneumocystis carinii pneumonia remains a prevalent opportunistic disease among immunocompromised individuals. Although aggressive prophylaxis has decreased the number of acute P. carinii pneumonia cases, many patients cannot tolerate the available drugs, and experience recurrence of the infection, which can be fatal. It is now generally agreed that the organism should be placed with the fungi, but the identification of extant fungal species representing its closest kins, remains debated. Most recent data indicate that P. carinii represents a diverse group of organisms. Since the lack of methods for the continuous subcultivation of this organism hampered P. carinii research, molecular cloning and nucleotide sequencing approaches led the way for understanding the biochemical nature of this pathogen. However, within the last 5 years, the development of improved protocols for isolating and purifying viable organisms from infected mammalian host lungs has enabled direct biochemical and metabolism studies on the organism. The protein moiety of the major high mol. wt surface antigen, represented by numerous isoforms, is encoded by different genes. These proteins are post-transcriptionally modified by carbohydrates and lipids. The organism has the shikimic acid pathway that leads to the formation of compounds which mammals cannot synthesise (e.g., folic acid), hence drugs that inhibit these pathways are effective against the pathogen. Ornithine decarboxylase has now been detected; rapid and complete depletion of polyamines occurs in response to difluoromethylornithine (DFMO). Instead of ergosterol (the major sterol of higher fungi), P. carinii synthesises distinct delta7, C-24-alkylated sterols. An unusual C32 sterol, pneumocysterol, has been identified in human-derived P. carinii. Another signature lipid discovered is cis-9,10-epoxy stearic acid. CoQ10, identified as the major ubiquinone homologue, is synthesised de novo by P. carinii. Atovaquone and other hydroxynaphthoquinone drugs with anti-P. carinii activity probably inhibit pathogen respiration as CoQ analogues. Unlike its effects on Plasmodium, atovaquone does not inhibit the P. carinii dihydroorotate dehydrogenase and pyrimidine metabolism.

Detection of Pneumocystis carinii with direct fluorescence antibody and calcofluor white stain

Direct fluorescence monoclonal antibody stain (DFA) was compared prospectively, with calcofluor white (CFW) stain for the diagnosis of Pneumocystis carinii in 163 respiratory specimens from 97 patients. The patient population included persons with HIV infection (58%), bone marrow transplant recipients (10%), immunosuppressed patients owing to chemotherapy (21%) and others (11%). Nineteen specimens including 12 sputa, six bronchoalveolar lavage fluids (BALs) and one induced sputum were positive by DFA. In contrast, only six sputa, and five BALs were positive by CFW. All specimens positive by CFW were also positive by DFA. Of 86 sputa that were negative by either method 29 were followed by more invasive sample collections. Three specimens were followed by induced sputum collection, 18 by BAL, six by lung biopsy, and two by pleural fluid aspiration. All the subsequent induced sputa, pleural fluids, and lung biopsies were negative by both methods. However, four of 18 subsequent BALs (22%) were positive by both methods, provided at least two CFW stained slides were examined per specimen. Except for expectorated sputum, it is concluded that CFW is a rapid and inexpensive test to detect P. carinii in most respiratory specimens.

Laboratory implementation of a rapid three-stain technique for detection of microorganisms from lower respiratory specimens

A rapid, cost-effective method for the evaluation of lower respiratory specimen has become increasingly important in the diagnosis of pulmonary diseases in immunocompromised patients. In the past, the technically demanding, time-consuming, and expensive Gomori-methenamine-silver (GMS) stain was the principal means for the evaluation of these specimens. In this study, we compared the GMS stain with a new rapid, three-stain protocol for the evaluation of lower respiratory specimens. Lower respiratory specimens were obtained by bronchoalveolar lavage (BAL). Conventional Wright/Giemsa and Gram stains were utilized, as well as a contemporary strain, calcofluor white (CW). A cell count was performed on the BAL specimens, and cytospins were stained by the three stains. The calcofluor white-stained slides were examined with an epi-fluorescent microscope, whereas the other stains were evaluated with a conventional light microscope. Gomorimethenamine-silver (GMS), acid-fast bacillus (AFB), and Papanicolaou (PAP) stains were performed as controls. Thirty-two BAL procedures were performed in 20 (63%) male patients and 12 (37%) female patients. The clinical diagnosis was pneumonia in 31% of the patients, malignant hematologic disease in 28%, acute respiratory distress syndrome (ARDS) in 9%, and acquired immunodeficiency syndrome (AIDS) in 28%. Of these specimens, 78% were adequate for interpretation and 22% were inadequate. Bacteria were found in 50% (16/32) of all BALs, fungi were found in 9% (3/32), and Pneumocystis carinii was found in 9% (3/32). Gram-positive bacteria were most frequently found in patients with pneumonia (80%, 4/5), whereas P. carinii was identified in patients with AIDS. There were no false-positive results. One CW stain was equivocal for P. carinii due to high fluorescent background. Laboratory implementation of the rapid, three-staining technique was accomplished without difficulty in microbiology and hematology laboratory sections. Specimen evaluation with the rapid staining protocol was technically easy to perform; however, experience in ultraviolet fluorescent microscopy was crucial for interpretation of CW stain. All results were available in 2 hr, cost was reduced by 30%, and the assays were available 7 days/week. Further studies are ongoing to substantiate the sensitivity, specificity, and predictive value of this technique, as well as clinical guidelines for its optimal utilization.

Pneumocystis carinii pneumonia in patients without acquired immunodeficiency syndrome: associated illness and prior corticosteroid therapy

OBJECTIVE

To determine the clinical spectrum of immunosuppressive conditions and systemic corticosteroid therapy associated with the development of Pneumocystis carinii pneumonia in a consecutive series of patients without acquired immunodeficiency syndrome (AIDS).

DESIGN

We retrospectively analyzed a consecutive series of 116 patients without AIDS who were assessed at Mayo Medical Center for a first episode of P. carinii pneumonia between 1985 and 1991.

METHODS

Medical records were examined to determine underlying immunosuppressive disorders, premorbid corticosteroid dosage and duration of therapy, associated infections, and subsequent respiratory failure and in-hospital mortality.

RESULTS

Conditions associated with a first episode of P. carinii pneumonia were hematologic malignant disorders (30.2%), organ transplantation (25.0%), inflammatory disorders (22.4%), solid tumors (12.9%), and miscellaneous conditions (9.5%). Regardless of the associated underlying disease, corticosteroids had been administered systemically in 105 patients (90.5%) within 1 month before the diagnosis of P. carinii pneumonia. The median daily corticosteroid dose was equivalent to 30 mg of prednisone; however, 25% of patients had received as little as 16 mg of prednisone daily. The median duration of corticosteroid therapy was 12 weeks before the development of pneumonia; however, P. carinii pneumonia developed after 8 weeks or less of corticosteroid therapy in 25% of these patients. Respiratory failure occurred in 43%, and in-hospital mortality was 34% for patients with P. carinii pneumonia in conditions other than AIDS.

CONCLUSION

Although these results do not suggest that premorbid administration of corticosteroids is the only factor that contributes to the development of P. carinii pneumonia in these patients, they show that, in this large consecutive series, systemic corticosteroid therapy, even in moderate doses, was administered to most patients during the month preceding the onset of P. carinii pneumonia. Consideration should be given to instituting P. carinii prophylaxis (when not contra-indicated) in patients for whom prolonged systemic corticosteroid therapy is prescribed.

Electrophoretic detection of chitinase isoenzymes using the PhastSystem

Zymographic assays are described for the detection of chitinase isoenzymes following isoelectric focusing. Method 1 used a polyacrylamide overlay gel containing glycol chitin. Following hydrolysis, visualisation of isoenzymes was achieved by fluorescent counter-staining of the gel with Fluorescent Brightener 28. Method 2 used a cellulose acetate membrane overlay which incorporates 4-methylumbelliferyl substrates, hydrolysis of which released a fluorescent product (4-methylumbelliferone). The pIs of chitinase isoenzymes were estimated by using coloured pI markers. A significant time advantage was obtained over previous methods. The method was used to demonstrate chitinase activity in control rat lungs and in rat lungs infected with the pathogen Pneumocystis carinii.