Pneumocystis carinii: Has the Name Really Been Changed?

Fun with fungi: a comprehensive review of common fungal organisms encountered in cytology

The ability to detect and diagnose infection is essential in the practice of cytopathology. The identification of suppurative or granulomatous inflammation should prompt careful evaluation for infection. Many of the most commonly encountered fungal organisms demonstrate characteristic microscopic appearances that allow accurate identification even with routine cytology stains, particularly when considered in the context of clinical factors such as geographic location, social history, patient immune status, and symptoms. Given the vital role cytopathologists play in the accurate diagnosis or presumptive identification of infections, this review explores the epidemiology, clinical manifestations, and morphologic features of common fungal pathogens in addition to their differential diagnoses and ancillary testing methods.

It is still PCP that can stand for Pneumocystis pneumonia: Appeal for generalized use of only one acronym

Twenty-years ago, considering the host specificity of Pneumocystis species, the human-derived Pneumocystis, Pneumocystis carinii formae specialis hominis, was renamed Pneumocystis jirovecii. Pneumocystis carinii formae specialis carinii was finally renamed Pneumocystis carinii and kept for the species derived from Rattus norvegicus. P. jirovecii is now widely used by most authors. The PCP acronym that initially referred to "Pneumocystis cariniipneumonia" was contemporaneously redefined to stand for Pneumocystispneumonia in order to avoid changing the acronym of the name of the disease that clinicians have used for several decades. Using analysis of multidata bases on PubMed, we have noted a recent acceleration in the use of PJP for Pneumocystis jiroveciipneumonia, which may be grammatically correct but not in accordance with retaining PCP, which was proposed in the early 2000s. Through this reminder, in order to standardize the literature on P. jirovecii, we plead for the use of only one acronym, PCP.

LAY SUMMARY

Through this reminder on Pneumocystis nomenclature, we plead for the use of only one acronym, PCP, the retention of which was proposed in the early 2000s, and which currently stands for Pneumocystispneumonia.

Diagnosis of Pneumocystis jirovecii Pneumonia in Pediatric Patients in Serbia, Greece, and Romania. Current Status and Challenges for Collaboration

Pneumocystis jirovecii can cause fatal Pneumocystis pneumonia (PcP). Many children have been exposed to the fungus and are colonized in early age, while some individuals at high risk for fungal infections may develop PcP, a disease that is difficult to diagnose. Insufficient laboratory availability, lack of knowledge, and local epidemiology gaps make the problem more serious. Traditionally, the diagnosis is based on microscopic visualization of Pneumocystis in respiratory specimens. The molecular diagnosis is important but not widely used. The aim of this study was to collect initial indicative data from Serbia, Greece, and Romania concerning pediatric patients with suspected PcP in order to: find the key underlying diseases, determine current clinical and laboratory practices, and try to propose an integrative future molecular perspective based on regional collaboration. Data were collected by the search of literature and the use of an online questionnaire, filled by relevant scientists specialized in the field. All three countries presented similar clinical practices in terms of PcP prophylaxis and clinical suspicion. In Serbia and Greece the hematology/oncology diseases are the main risks, while in Romania HIV infection is an additional risk. Molecular diagnosis is available only in Greece. PcP seems to be under-diagnosed and regional collaboration in the field of laboratory diagnosis with an emphasis on molecular approaches may help to cover the gaps and improve the practices.

Common Infections Following Lung Transplantation

The lungs are the only transplanted organ in direct contact with the ‘outside world’. Infection is a significant cause of morbidity and mortality in lung transplantation. Early accurate diagnosis and optimal management is essential to prevent short and long term complications. Bacteria, including Mycobacteria and Nocardia, viruses and fungi are common pathogens. Organisms may be present in the recipient prior to transplantation, transmitted with the donor lungs or acquired after transplantation. The degree of immunosuppression and the routine use of antimicrobial prophylaxis alters the pattern of post-transplant infections.

Pneumocystis jirovecii pneumonia in pediatric patients: an analysis of 15 confirmed consecutive cases during 14 years

Purpose

Pneumocystis jirovecii pneumonia occurs in various immunocompromised patients. Despite the prophylaxis strategies in clinical practice, certain patients develop P. jirovecii pneumonia. This study was performed to investigate pediatric cases with P. jirovecii pneumonia in a single center.

Methods

We identified pediatric patients younger than 19 years with microbiologically confirmed P. jirovecii pneumonia from January 2000 to February 2014. A retrospective chart review was performed.

Results

Fifteen episodes of P. jirovecii pneumonia in 14 patients were identified with median age of 8.3 years (range, 0.4–18.6 years). Among these patients, 11 patients had hematology-oncology diseases, 2 had primary immunodeficiency disorders (one with severe combined immunodeficiency and the other with Wiskott Aldrich syndrome), 1 had systemic lupus erythematosus and 1 received kidney transplant. Four patients were transplant recipients; 1 allogeneic and 2 autologous hematopoietic cell transplant and 1 with kidney transplant. The median absolute lymphocyte count at the diagnosis of P. jirovecii pneumonia was 5,156 cells/mm³ (range, 20–5,111 cells/mm³). In 13 episodes (13 of 15, 86.7%), patients were not receiving prophylaxis at the onset of P. jirovecii pneumonia. For treatment, trimethoprim/sulfamethoxazole was given as a main therapeutic agent in all 15 episodes. Steroid was given in 9 episodes (60%). Median treatment duration was 15 days (range, 4–33 days). Overall mortality at 60 days was 35.7% (5 of 14).

Conclusion

Majority of our patients developed P. jirovecii pneumonia while not on prophylaxis. Continuous efforts and more data are needed to identify high risk patients who may get benefit from P. jirovecii pneumonia prophylaxis.

Respiratory Tract and Mediastinum

Normal cytology, abnormal and atypical cells, non-cellular components, and infectious cell changes are largely described together with benign, malignant, and neuroendocrine lesions regarding exfoliative and aspiration cytology of the lung. A separate section broadly addresses diagnostic findings and differential diagnoses in bronchoalveolar washings.

The section ‘Fine needle aspiration biopsy of mediastinal disorders’ covers in particular biopsy techniques, accuracy of liquid-based cytology, and the complex lesions of the thymus gland. Cytodiagnostic algorithms of the major benign and malignant pulmonary and mediastinal lesions and their respective differential diagnoses are additionally presented in synoptic setups.

[Pneumocystis jirovecii: what does this mean?]

Pneumocystis was discovered nearly a century ago. It causes fatal pneumonia in immunocompromised individuals, especially in AIDS patients. Knowledge of the different species remained rudimentary until the mid-eighties when DNA analysis revealed its extensive diversity. In fact, it is no longer considered as a zoonosis. Pneumocystis organisms derived from different hosts have very different DNA sequences, indicating multiple species. Due to the genetic and functional disparities, the organism that causes human PCP is now named Pneumocystis jirovecii/Frenkel, 1999. We continue to call Pneumocystis carinii the species found in rats. This will allow for a single international language and avoid confusion. Changing the organism's name does not preclude the use of the well-known acronym PCP because it can also be read "PneumoCystis Pneumonia." The DNA sequences and genotypage have shown that variations exist among samples of P. jiroveci. Molecular biology is helpful in the study of the mechanisms of transmission, which can only occur in the same host and the different resistances as well as providing a better understanding of the relationship between host and pathogen. P. jirovecii pneumonia in immunosuppressed patients was previously thought to result from the reactivation of a latent infection acquired in early childhood. However, today, it is believed to result from a new infection from an exogenous source.

Pneumocystis jirovecii Pneumonia

Pneumocystis jirovecii has gained attention during the last decade in the context of the AIDS epidemic and the increasing use of cytotoxic and immunosuppressive therapies. This article summarizes current knowledge on biology, pathophysiology, epidemiology, diagnosis, prevention, and treatment of pulmonary P jirovecii infection, with a particular focus on the evolving pathophysiology and epidemiology. Pneumocystis pneumonia still remains a severe opportunistic infection, associated with a high mortality rate.

Successful intermittent prophylaxis with trimethoprim/sulfamethoxazole 2 days per week for Pneumocystis carinii (jiroveci) pneumonia in pediatric oncology patients

OBJECTIVE

This study was conducted to determine the efficacy of dosing trimethoprim/sulfamethoxazole on 2 consecutive days per week for the prevention of Pneumocystis carinii (jiroveci) pneumonia in a pediatric leukemia and lymphoma population and to determine whether trimethoprim/sulfamethoxazole contributes to neutropenia during maintenance therapy.

METHODS

Charts were reviewed for all pediatric patients with leukemia and lymphoma diagnosed between January 1, 1993, and December 31, 2002. Data were collected through April 1, 2004.

RESULTS

A total of 575 charts were reviewed; 529 patients were included in the analysis. A total of 482 (345 leukemia, 137 lymphoma) patients were evaluated on trimethoprim/sulfamethoxazole dosed 2 consecutive days per week for 268074 patient-days. No breakthrough cases were documented in compliant patients; 2 noncompliant patients developed P. carinii pneumonia. A total of 238 patients who were on trimethoprim/sulfamethoxazole prophylaxis and 13 patients who were receiving an alternative medication prophylaxis were evaluated for neutropenia during maintenance therapy. The median number of maintenance days on trimethoprim/sulfamethoxazole was 605.5 days and on alternative drug was 617 days. The median number of neutropenic maintenance days on trimethoprim/sulfamethoxazole was 15.5 days and on the alternative drug was 16 days. The median proportion of neutropenic days per patient was 0.029 on trimethoprim/sulfamethoxazole and 0.022 on the alternative drug.

CONCLUSIONS

Intermittent dosing of trimethoprim/sulfamethoxazole on 2 consecutive days per week is an effective alternative prophylactic regimen for P. carinii pneumonia in pediatric patients with leukemia and lymphoma. This analysis does not support a difference in neutropenia during maintenance therapy between patients who are treated with trimethoprim/sulfamethoxazole versus an alternative drug.

Current insights into the biology and pathogenesis of Pneumocystis pneumonia

The fungal infection Pneumocystis pneumonia is the most prevalent opportunistic infection in patients with AIDS. Although the analysis of this opportunistic fungal pathogen has been hindered by the inability to isolate it in pure culture, the use of molecular techniques and genomic analysis have brought insights into its complex cell biology. Analysis of the intricate relationship between Pneumocystis and the host lung during infection has revealed that the attachment of Pneumocystis to the alveolar epithelium promotes the transition of the organism from the trophic to the cyst form. It also revealed that Pneumocystis infection elicits the production of inflammatory mediators, culminating in lung injury and impaired gas exchange. Here we discuss these and other recent findings relating to the biology and pathogenesis of this intractable fungus.