Dynamics of Pneumocystis carinii Air Shedding During Experimental Pneumocystosis

Choukri, F.; Aliouat, El Moukhtar; Menotti, Jean; Totet, Anne; Gantois, Nausicâa; Garin, Y. J. F.; Bergeron, Vance; Dei‐Cas, Eduardo; Derouin, Francis

doi:10.1093/infdis/jir018

Cited by 28 publications

(23 citation statements)

References 15 publications

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“…On the contrary, the transmission of Pneumocystis has long been understood to be between individuals via air from experiments performed in immunocompromised rats or nude mice 27, 28 with Pneumocystis DNA detected in the surrounding air of infected immunosuppressed or immunocompetent animals 29– 31 . The same evidence has also been found in humans with the observation of P. jirovecii DNA detection in the surrounding air of patients or healthcare workers harboring P. jirovecii in their respiratory tract 32– 35 , making airborne transmission the most likely route of acquisition in humans.…”

Section: Pathophysiology Of Pneumocystis Jirovecii Pneumoniamentioning

confidence: 99%

“…have shown that patients receiving immunosuppressive therapy for rheumatoid arthritis with P. jirovecii DNA detection without respiratory symptoms have developed PCP in the next 2 to 4 weeks 72 . Upon P. jirovecii exposure or reactivation in immunocompromised hosts, the fungal load initially not detectable will increase until a plateau at the stage of PCP 29 . The rapidity of this increase should vary according to the immune status and the degree of immunosuppression ( Figure 1) 21, 73 .…”

Section: The Concept Of “Colonization”mentioning

confidence: 99%

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Pneumocystis jirovecii detection in asymptomatic patients: what does its natural history tell us?

Alanio

Bretagne

2017

F1000Res

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Pneumocystis jirovecii is an unusual ascomycetous fungus that can be detected in the lungs of healthy individuals. Transmission from human to human is one of its main characteristics in comparison with other fungi responsible for invasive infections. P. jirovecii is transmitted through the air between healthy individuals, who are considered to be the natural reservoir, at least transiently. In immunocompromised patients, P. jirovecii multiplies, leading to subacute infections and acute life-threatening pneumonia, called Pneumocystis pneumonia [PCP]. PCP is caused by genotypically distinct mixtures of organisms in more than 90% of cases, reinforcing the hypothesis that there is constant inhalation of P. jirovecii from different contacts over time, although reactivation of latent organisms from previous exposures may be possible. Detection of P. jirovecii DNA without any symptoms or related radiological signs has been called “colonization”. This situation could be considered as the result of recent exposure to P. jirovecii that could evolve towards PCP, raising the issue of cotrimoxazole prophylaxis for at-risk quantitative polymerase chain reaction (qPCR)-positive immunocompromised patients. The more accurate way to diagnose PCP is the use of real-time quantitative PCR, which prevents amplicon contamination and allows determination of the fungal load that is mandatory to interpret the qPCR results and manage the patient appropriately. The detection of P. jirovecii in respiratory samples of immunocompromised patients should be considered for potential risk of developing PCP. Many challenges still need to be addressed, including a better description of transmission, characterization of organisms present at low level, and prevention of environmental exposure during immunodepression.

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Section: Pathophysiology Of Pneumocystis Jirovecii Pneumoniamentioning

confidence: 99%

Section: The Concept Of “Colonization”mentioning

confidence: 99%

Pneumocystis jirovecii detection in asymptomatic patients: what does its natural history tell us?

Alanio

Bretagne

2017

F1000Res

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“…Collection of air samples in the environment air surrounding infected rats was performed as previously described [18] with minor modification. Briefly, a specific device consisting of Coriolis®µ biocollector (Bertin Technologies, Montigny, France) directly connected to a HEPA-filtered air sampling chamber was used.…”

Section: Methodsmentioning

confidence: 99%

“…As we previously showed that Pneumocystis was detectable and quantifiable in the close environment of patients or rats with PCP [17], [18], we examined the kinetics of infection and airborne excretion of Pneumocystis by immunocompetent rats following experimental infection and reinfection with P. carinii .…”

Section: Introductionmentioning

confidence: 99%

Evidence of Airborne Excretion of Pneumocystis carinii during Infection in Immunocompetent Rats. Lung Involvement and Antibody Response

et al. 2013

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To better understand the role of immunocompetent hosts in the diffusion of Pneumocystis in the environment, airborne shedding of Pneumocystis carinii in the surrounding air of experimentally infected Sprague Dawley rats was quantified by means of a real-time PCR assay, in parallel with the kinetics of P. carinii loads in lungs and specific serum antibody titres. Pneumocystis-free Sprague Dawley rats were intratracheally inoculated at day 0 (d0) and then followed for 60 days. P. carinii DNA was detected in lungs until d29 in two separate experiments and thereafter remained undetectable. A transient air excretion of Pneumocystis DNA was observed between d14 and d22 in the first experiment and between d9 and d19 in the second experiment; it was related to the peak of infection in lungs. IgM and IgG anti-P. carinii antibody increase preceded clearance of P. carinii in the lungs and cessation of airborne excretion. In rats receiving a second challenge 3 months after the first inoculation, Pneumocystis was only detected at a low level in the lungs of 2 of 3 rats at d2 post challenge and was never detected in air samples. Anti-Pneumocystis antibody determinations showed a typical secondary IgG antibody response. This study provides the first direct evidence that immunocompetent hosts can excrete Pneumocystis following a primary acquired infection. Lung infection was apparently controlled by the immune response since fungal burdens decreased to become undetectable as specific antibodies reached high titres in serum. This immune response was apparently protective against reinfection 3 months later.

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“…Ainsi, pour des raisons scientifiques mais également pratiques (comme prévenir la transmission nosocomiale de la PcP), la communauté scientifique s'est récemment intéressée à l'étude de la dynamique de contamination par Pneumocystis de l'environnement aérien d'hôtes atteints de pneumocystose. Il a ainsi été montré que Pneumocystis était détectable dans l'air exhalé de rats infectés, la charge fongique aérienne étant proportionnelle à la charge fongique pulmonaire [29]. Chez l'homme, la même équipe a montré que P. jirovecii était dispersé dans l'environnement aérien proche des patients développant une PcP et que la charge fongique diminuait quand on s'éloignait du patient jusqu'à devenir indétectable [30].…”

Section: Les Espèces De Pneumocystis Sont Activement Transmises Par Vunclassified

La transmission des infections àPneumocystis

2012

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Dynamics of Pneumocystis carinii Air Shedding During Experimental Pneumocystosis

Cited by 28 publications

References 15 publications

Pneumocystis jirovecii detection in asymptomatic patients: what does its natural history tell us?

Pneumocystis jirovecii detection in asymptomatic patients: what does its natural history tell us?

Evidence of Airborne Excretion of Pneumocystis carinii during Infection in Immunocompetent Rats. Lung Involvement and Antibody Response

La transmission des infections àPneumocystis

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