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Clinical Microbiology Reviews Apr 1991Pneumocystis carinii has been recognized as a cause of pneumonia in immunocompromised patients for over 40 years. Until the 1980s, Pneumocystis pneumonia... (Review)
Review
Pneumocystis carinii has been recognized as a cause of pneumonia in immunocompromised patients for over 40 years. Until the 1980s, Pneumocystis pneumonia (pneumocystosis) was most often seen in patients undergoing chemotherapy for malignancy or transplantation. Infection could be prevented by trimethoprim-sulfamethoxazole prophylaxis; thus, it was an uncommon clinical problem. With the onset of the AIDS epidemic, Pneumocystis pneumonia has become a major problem in the United States because it develops in approximately 80% of patients with AIDS and because almost two-thirds of patients have adverse reactions to anti-Pneumocystis drugs. Thus, physicians and laboratories in any community may be called upon to diagnose and provide care for patients with Pneumocystis pneumonia. The classification of the organism is currently controversial, but it is either a protozoan or a fungus. P. carinii appears to be acquired during childhood by inhalation and does not cause clinical disease in healthy persons but remains latent. If the person becomes immunosuppressed, the latent infection may become activated and lead to clinical disease. Damage of type I pneumocytes by Pneumocystis organisms leads to the foamy alveolar exudate which is characteristic of the disease. Diagnosis is established by morphologic demonstration of Pneumocystis organisms in material from the lungs. Current efforts to find better anti-Pneumocystis drugs should provide more effective therapy and prophylaxis.
Topics: Acquired Immunodeficiency Syndrome; Humans; Opportunistic Infections; Pneumocystis; Pneumonia, Pneumocystis
PubMed: 2070342
DOI: 10.1128/CMR.4.2.137 -
Clinical Microbiology Reviews Apr 2012Although the incidence of Pneumocystis pneumonia (PCP) has decreased since the introduction of combination antiretroviral therapy, it remains an important cause of... (Review)
Review
Although the incidence of Pneumocystis pneumonia (PCP) has decreased since the introduction of combination antiretroviral therapy, it remains an important cause of disease in both HIV-infected and non-HIV-infected immunosuppressed populations. The epidemiology of PCP has shifted over the course of the HIV epidemic both from changes in HIV and PCP treatment and prevention and from changes in critical care medicine. Although less common in non-HIV-infected immunosuppressed patients, PCP is now more frequently seen due to the increasing numbers of organ transplants and development of novel immunotherapies. New diagnostic and treatment modalities are under investigation. The immune response is critical in preventing this disease but also results in lung damage, and future work may offer potential areas for vaccine development or immunomodulatory therapy. Colonization with Pneumocystis is an area of increasing clinical and research interest and may be important in development of lung diseases such as chronic obstructive pulmonary disease. In this review, we discuss current clinical and research topics in the study of Pneumocystis and highlight areas for future research.
Topics: Carrier State; HIV Infections; Humans; Immunocompromised Host; Pneumocystis carinii; Pneumonia, Pneumocystis
PubMed: 22491773
DOI: 10.1128/CMR.00013-12 -
Clinics in Chest Medicine Sep 1988This article covers the biology, epidemiology, and pathology of infection with Pneumocystis carinii. The clinical presentation, course, and treatment of pneumonia caused... (Review)
Review
This article covers the biology, epidemiology, and pathology of infection with Pneumocystis carinii. The clinical presentation, course, and treatment of pneumonia caused by this organism in patients infected with the human immunodeficiency virus is discussed.
Topics: Acquired Immunodeficiency Syndrome; Animals; Humans; Pneumocystis; Pneumonia, Pneumocystis; Prognosis
PubMed: 3044678
DOI: No ID Found -
Current Opinion in Microbiology Dec 2017Pneumocystis jirovecii causes clinical pneumonia in immunocompromised hosts. Despite this, the inability to cultivate this organism in vitro has likely hindered the... (Review)
Review
Pneumocystis jirovecii causes clinical pneumonia in immunocompromised hosts. Despite this, the inability to cultivate this organism in vitro has likely hindered the field in ascertaining the true impact of Pneumocystis in human infection. However the recent release of the genome as well as in advances in understanding host genetics, and other risk factors for infection and robust experimental models of disease have shed new light on the impact of this fungal pathogen as to better define populations at risk. This review will highlight these recent advances as well as highlight future needed areas of research.
Topics: Animals; Humans; Pneumocystis carinii; Pneumonia, Pneumocystis
PubMed: 29136537
DOI: 10.1016/j.mib.2017.10.019 -
Therapeutic Advances in Respiratory... Feb 2011Pneumocystis is an opportunistic fungal pathogen that causes an often-lethal pneumonia in immunocompromised hosts. Although the organism was discovered in the early... (Review)
Review
Pneumocystis is an opportunistic fungal pathogen that causes an often-lethal pneumonia in immunocompromised hosts. Although the organism was discovered in the early 1900s, the first cases of Pneumocystis pneumonia in humans were initially recognized in Central Europe after the Second World War in premature and malnourished infants. This unusual lung infection was known as plasma cellular interstitial pneumonitis of the newborn, and was characterized by severe respiratory distress and cyanosis with little or no fever and no pathognomic physical signs. At that time, only anecdotal cases were reported in adults and usually these patients had a baseline malignancy that led to a malnourished state. In the 1960-1970s additional cases were described in adults and children with hematological malignancies, but Pneumocystis pneumonia was still considered a rare disease. However, in the 1980s, with the onset of the HIV epidemic, Pneumocystis prevalence increased dramatically and became widely recognized as an opportunistic infection that caused potentially life-treating pneumonia in patients with impaired immunity. During this time period, prophylaxis against this organism was more generally instituted in high-risk patients. In the 1990s, with widespread use of prophylaxis and the initiation of highly active antiretroviral therapy (HAART) in the treatment of HIV-infected patients, the number of cases in this specific population decreased. However, Pneumocystis pneumonia still remains an important cause of severe pneumonia in patients with HIV infection and is still considered a principal AIDS-defining illness. Despite the decreased number of cases among HIV-infected patients over the past decade, Pneumocystis pneumonia continues to be a serious problem in immunodeficient patients with other immunosuppressive conditions. This is mostly due to increased use of immunosuppressive medications to treat patients with autoimmune diseases, following bone marrow and solid organ transplantation, and in patients with hematological and solid malignancies. Patients with hematologic disorders and solid organ and hematopoietic stem cell transplantation are currently the most vulnerable groups at risk for developing this infection. However, any patient with an impaired immunity, such as those receiving moderate doses of oral steroids for greater than 4 weeks or those receiving other immunosuppressive medications are at also at significant risk.
Topics: AIDS-Related Opportunistic Infections; Humans; Pneumocystis; Pneumonia, Pneumocystis; Risk Factors
PubMed: 20736243
DOI: 10.1177/1753465810380102 -
Medical Mycology Journal 2016Pneumocystis jirovecii is a prototypical opportunistic pathogen, causing an asymptomatic or mild infection in normal hosts and fulminating pneumonia (Pneumocystis... (Review)
Review
Pneumocystis jirovecii is a prototypical opportunistic pathogen, causing an asymptomatic or mild infection in normal hosts and fulminating pneumonia (Pneumocystis pneumonia, PCP) in immunocompromised hosts. PCP is a leading cause of morbidity and mortality in immunocompromised patients such as AIDS patients. Microscopic detection of cysts and trophic forms of P. jirovecii in respiratory secretions is simple and useful but may underestimate the P. jirovecii infection. Conventional polymerase chain reaction (PCR) and nested PCR increase the sensitivity and specificity to identify PCP and provide an approach to discriminate PCP from pulmonary P. jirovecii colonization, but the targeted genes and cut-off value from quantitative real-time PCR remain to be determined. Serum (1-3)-β-D-glucan level and the specific serum antibody titer are ancillary indicators for PCP diagnosis. The successful cultivation of P. jirovecii in vitro is an important progress for PCP research. The diagnosis of PCP relies on the combination of these laboratory examinations as well as the clinical presentations.
Topics: Antibodies, Fungal; Biomarkers; DNA, Fungal; Humans; Immunocompromised Host; Pneumocystis carinii; Pneumonia, Pneumocystis; Polymerase Chain Reaction; Proteoglycans; Sensitivity and Specificity; beta-Glucans
PubMed: 27904052
DOI: 10.3314/mmj.16-00019 -
Pathologie-biologie Dec 2013Pneumocystosis is a common opportunistic infection in immunocompromised patients, especially in AIDS patients. The diagnosis of this pneumonia has presented several... (Review)
Review
Pneumocystosis is a common opportunistic infection in immunocompromised patients, especially in AIDS patients. The diagnosis of this pneumonia has presented several difficulties due to the low sensitivity of conventional staining methods and the absence of culture system for Pneumocystis. The molecular biology techniques, especially the PCR, have improved the detection of DNA of this fungus in invasive and noninvasive samples, and in the environment which highlighted human transmission and the existence of environmental source of Pneumocystis. In addition, various molecular biology techniques were used for typing of Pneumocystis strains, especially P. jirovecii, which is characterized by a significant genetic biodiversity. Finally, the widespread use of cotrimoxazole for the treatment and prophylaxis of pneumocystosis has raised questions about possible resistance to sulfa drugs in P. jirovecii.
Topics: Animals; Disease Reservoirs; Disease Susceptibility; Host Specificity; Host-Pathogen Interactions; Humans; Immunocompromised Host; Opportunistic Infections; Pneumocystis; Pneumonia, Pneumocystis
PubMed: 23849772
DOI: 10.1016/j.patbio.2013.05.001 -
Emerging Infectious Diseases Sep 2002The disease known as Pneumocystis carinii pneumonia (PCP) is a major cause of illness and death in persons with impaired immune systems. While the genus Pneumocystis has... (Review)
Review
The disease known as Pneumocystis carinii pneumonia (PCP) is a major cause of illness and death in persons with impaired immune systems. While the genus Pneumocystis has been known to science for nearly a century, understanding of its members remained rudimentary until DNA analysis showed its extensive diversity. Pneumocystis organisms from different host species have very different DNA sequences, indicating multiple species. In recognition of its genetic and functional distinctness, the organism that causes human PCP is now named Pneumocystis jiroveci Frenkel 1999. Changing the organism's name does not preclude the use of the acronym PCP because it can be read "Pneumocystis pneumonia." DNA sequence variation exists among samples of P. jiroveci, a feature that allows reexamination of the relationships between host and pathogen. Instead of lifelong latency, transient colonization may be the rule.
Topics: AIDS-Related Opportunistic Infections; Acquired Immunodeficiency Syndrome; Genotype; Humans; Phylogeny; Pneumocystis; Pneumocystis Infections; Pneumonia, Pneumocystis; Species Specificity; Terminology as Topic
PubMed: 12194762
DOI: 10.3201/eid0809.020096 -
Annals of the New York Academy of... 1990
Review
Topics: Pneumocystis; Pneumonia, Pneumocystis; RNA, Ribosomal
PubMed: 2078032
DOI: 10.1111/j.1749-6632.1990.tb17861.x -
Medical Mycology Feb 2005Species of the genus Pneumocystis exist as opportunistic fungal pathogens and are associated with severe pneumonia and pulmonary complications in immunocompromised... (Review)
Review
Species of the genus Pneumocystis exist as opportunistic fungal pathogens and are associated with severe pneumonia and pulmonary complications in immunocompromised individuals. Although prophylactic therapy for Pneumocystis has significantly decreased the overall incidence of infection, more than 80% of cases in current patient populations are considered breakthrough cases. In the HIV-infected population, in the years following the initiation of highly active antiretroviral therapy (HAART), significant reductions in the incidence of Pneumocystis infection were observed, although trends over the last several years suggest that the incidence of Pneumocystis has plateaued rather than decreased. Furthermore, with the more prominent usage of immunosuppressive therapies, the frequency of Pneumocystis infection in the HIV-negative population, such as those with hematologic malignancies and those who have undergone transplantation, has risen significantly. Investigating host defense mechanisms against P. carinii has historically been problematic due to the difficulty in achieving continuous in vitro propagation of proliferating Pneumocytis organisms. Nevertheless, clinical and experimental studies have documented that host defense against Pneumocystis involves a concerted effort between innate, cell-mediated (T lymphocyte) and humoral (B lymphocyte) responses. However, the pulmonary environment is a tissue site where heightened inflammatory responses can often lead to inflammation-mediated injury, thereby contributing to the pathogenesis of Pneumocystis infection. Accordingly, clearance of Pneumocystis from the pulmonary environment is dependent on a delicate equilibrium between the inflammatory response and immune-mediated clearance of the organism. Furthermore, innate and adaptive responses against Pneumocystis are strikingly similar to those against other medically-important fungi, thus providing additional evidence that Pneumocystis exists as a fungal organism.
Topics: Animals; Humans; Mice; Mice, SCID; Opportunistic Infections; Pneumocystis; Pneumonia, Pneumocystis
PubMed: 15712604
DOI: 10.1080/13693780400015360