Pneumocystis jirovecii colonization in patients treated with infliximab.

BACKGROUND: Infliximab, a chimeric antitumour necrosis factor (TNF) monoclonal antibody, has become an established effective therapy for inflammatory rheumatic disease. However, TNF is a critical factor in host defence, and the suppression of its biological activity may be associated with the increased risk of opportunistic infections. The frequent use of infliximab in clinical practice has identified Pneumocystis jirovecii pneumonia (PcP) as a serious complication. Individuals colonized with Pneumocystis may be at high risk of development of PcP when they have undergone immunosuppression. Hence, we addressed the question of the frequency of Pneumocystis colonization among patients treated with infliximab. DESIGN: We examined 125 oropharyngeal washes collected from 78 individuals with rheumatoid arthritis, 30 with ankylosing spondylitis and 17 with psoriatic arthritis, half of them underwent infliximab therapy, using a real-time polymerase chain reaction assay that employs specific primers from a portion of the mitochondrial large-subunit rRNA gene of P. jirovecii. RESULTS: Pneumocystis jirovecii colonization was detected in 32 (25·6%) patients. In a multivariate regression model, only duration of infliximab treatment for more than 3 years and use of corticosteroid were significantly and independently associated with risk of Pneumocystis colonization. However, the effect of corticosteroid on P. jirovecii colonization rate was not linearly dose dependent as showed other logistic regression analysis. CONCLUSIONS: There is a high rate of P. jirovecii colonization among patients with rheumatologic diseases treated with infliximab. The identification of patients colonized by P. jirovecii before starting the treatment with infliximab could be a strategy for PcP prevention.

Pneumocystis jirovecii transmission from immunocompetent carriers to infant.

We report a case of Pneumocystis jirovecii transmission from colonized grandparents to their infant granddaughter. Genotyping of P. jirovecii showed the same genotypes in samples from the infant and her grandparents. These findings support P. jirovecii transmission from immunocompetent carrier adults to a susceptible child.

Systemic inflammation in patients with chronic obstructive pulmonary disease who are colonized with Pneumocystis jiroveci.

In chronic obstructive pulmonary disease, high levels of airway and systemic inflammatory markers are associated with a faster decrease in lung function. Our study shows that patients colonized by Pneumocystis jiroveci have higher proinflammatory cytokine levels than do noncolonized patients. This suggests that Pneumocystis may play a role in disease progression.

Comparison of two ELISA assays for anti-Sp100 determination.

Antibodies to Sp100 have been described not only in primary biliary cirrhosis (PBC), but also in other diseases. Two assays for detection of Sp100 levels by enzyme-linked immunosorbent assay (ELISA) have been compared in a cohort of patients from our area: (a) Sp100 kit produced by IMTEC, Immunodiagnostica GmbH, and (b) Quanta Lite Sp100 kit produced by INOVA Diagnostics. We analyze here the correlation between the two assays and compare their efficiency in diagnosing PBC. We also comment on the exceptions derived from reactivity with other diseases. We studied 78 sera by IIF with the typical multiple nuclear dots (MND) pattern from patients who suffered from PBC, hepatopathies different from PBC, systemic lupus erythematosus (SLE), other connective tissue diseases (CTD), skeletal diseases, lung diseases, hematological disorders, a miscellaneous group, and a healthy IIF negative control group. The tests work equally well despite their different quantification system: (a) it is based on a standard curve; and (b) it is based on a single-point antigen-specific calibration. Some discrepancies could be explained by differences in the immunodominant epitope used in the ELISA. The main finding of this study is that the presence of MND/Sp100-positive antibodies were detected not only in hepatic diseases, mainly PBC, but also in other clinical conditions, confirmed by both tests. Diagnosis of PBC must be established in the right clinical context, because other diseases recognizing the same epitope, mainly SLE, may also show high Sp100 levels. Sera from PBC patients with antimitochondrial antibodies (AMA) showed higher anti-Sp100 than the AMA-negative group.

Pneumocystis jiroveci genotypes and primary infection.

This study describes the molecular typing of Pneumocystis jiroveci organisms from 5 nonpremature immunocompetent infants who developed a primary infection. Four P. jiroveci internal transcribed spacer (ITS) types were identified. All have been previously described in reports concerning immunosuppressed adults with pneumocystosis. Present data suggest that identical types can be implicated either in first contact or in additional contacts between fungus and host and that both immunocompetent infants and immunocompromised patients may be part of a common human reservoir for the fungus.

[Genotypic resistance to sulfamide drugs among patients with Pneumocystis jiroveci pneumonia]. / Resistencia genotípica a sulfamidas en pacientes con neumonía por Pneumocystis jiroveci.

BACKGROUND AND OBJECTIVE: The absence of culture methods to recognize the presence of resistance to sulfa or sulfone drugs in Pneumocystis jiroveci has led to develop molecular techniques based on the identification of mutations in the dihydropteroate synthase gene (DHPS). The aim of this study was to determine the frequency of these mutations in our geographical area, since in Spain there is no information concerning this issue. PATIENTS AND METHOD: The study included all Pneumocystis pneumonia cases identified in our hospital during two years. Diagnosis was made by nested PCR in bronchoalveolar lavage samples. DHPS-3 and DHPS-4 primers were used to amplify the DHPS gene and mutations associated with sulfa resistance were identified using a restriction fragment length polymorphism assay. RESULTS: In 9 out of the 12 cases identified, DHPS could be amplified (75%) from which 3 (33.3%) showed some mutation linked to sulfa resistance. CONCLUSIONS: In our area, we have found a relatively high frequency of pneumonia caused by P. jiroveci's strains with mutations associated with sulfa resistance.

High prevalence of Pneumocystis jiroveci colonization among young HIV-infected patients.

BACKGROUND: Pneumocystis colonization in young HIV-infected patients has been poorly studied. The aim of this study was to analyze the prevalence of P jiroveci colonization in a cohort of young HIV-infected patients. MATERIAL AND METHODS: We designed a basal cross-sectional study in 20 young HIV-infected patients to determine the prevalence of P jiroveci colonization in oropharyngeal wash samples studied by nested polymerase chain reaction (PCR). Subsequently, patients were followed up during 50 weeks to observe the development of Pneumocystis pneumonia (PCP). RESULTS: P jiroveci colonization was detected in eight (40%) of the 20 oropharyngeal wash samples. Genotype 85C/248C was the most frequent. After 50 weeks of follow-up, one colonized patient with advanced immunodepression developed PCP. CONCLUSIONS: We have found a high prevalence of P jiroveci colonization in young HIV-infected patients with a major prevalence of genotype 1 (85C/248C). Further studies are necessary to clarify if Pneumocystis colonization could be a potential risk factor of developing PCP in young HIV infected patients.

Pneumocystis jiroveci dihydropteroate synthase gene mutations among colonized individuals and Pneumocystis pneumonia patients from Spain.

Cotrimoxazole, an association of trimethoprim and sulfamethoxazole, and dapsone, are mainstays for the prophylaxis and treatment of Pneumocystis pneumonia (PcP). The inability to culture Pneumocystis prevents routine susceptibility testing and detection of drug resistance. Instead, molecular techniques have been used to detect Pneumocystis jiroveci dihydropteroate synthase (DHPS) mutations that cause sulfa resistance in other microorganisms. The most frequent DHPS mutations occur at nucleotide positions 165 and 171, which lead to an amino acid change at positions 55 and 57. Several studies suggest that these mutations are associated with the failure of chemoprophylaxis for PcP. The aim was to establish the frequency and characteristics of P jiroveci DHPS mutations among colonized individuals and PcP patients from Spain. A total of 50 colonized individuals and 25 PcP patients were studied. DHPS polymorphisms were identified by restriction fragment length polymorphism assay. The analysis provided a rate of 28% of DHPS gene mutations in our population, with the presence of all possible polymorphisms described. The presence of mutations was higher in PcP patients than in colonized subjects (40% vs 22%), probably because of the chemoprophylaxis used in PcP patients. The comparison between patients with and without DHPS mutations did not show statistical differences due to age, sex, steroid use, sulfa drug exposure, or smoking. A high rate of DHPS mutations in our area of Spain, not only confined to patients previously exposed to sulfa drugs, is shown in this study. As well as PcP patients, colonized individuals who harbor P jiroveci strains with DHPS mutations could play a major role in the transmission cycle of these mutations, representing a reservoir and source of infection for susceptible individuals. Further research is thus warranted to assess the true scope of the problem and to design rational preventive strategies.

Evidence for high prevalence of Pneumocystis jirovecii exposure among Cameroonians.

Cameroon lacks the capacity for routine Pneumocystis pneumonia (PcP) diagnosis, thus, the prevalence of Cameroonian exposure to this microbe is unknown. It is known that Pneumocystis infecting different mammalian host species represent diverse phylogenetic backgrounds and are now designated as separate species. The highly sensitive nature of ELISA and the specificity afforded by using human-derived P. jirovecii Msg peptides has been shown to be useful for serological analysis of human sera. Thus, sera from patients in Yaoundé, the capital city of Cameroon, were analyzed for anti-P. jirovecii antibodies by enzyme-linked immunosorbent assay (ELISA) using three recombinant major surface glycoprotein (Msg) peptide fragments, MsgA1, MsgB, and MsgC1. Based on serum recognition of one or more of the three fragments, 82% of the total samples analyzed was positive for antibodies to P. jirovecii Msg, indicating high prevalence of P. jirovecii infection or colonization among Cameroonians. Different Msg fragments appear to be recognized more frequently by sera from different geographic regions of the globe. Antibodies in the Cameroonian serum samples recognized MsgA1>MsgC1>MsgB, suggesting that different P. jirovecii strains exist in different parts of the world and/or human populations differ in their response to P. jirovecii. Also, HIV(+) patients diagnosed with respiratory infections (such as TB and pneumonia) and maintained on trimethoprim/sulfamethoxazol prophylaxis had relatively lower anti-Msg titers. Whether PcP prophylaxis has significant effects on the quality of life among HIV(+) patients in Cameroon warrants further investigation.

Antiphospholipid antibodies investigation in Pneumocystis jirovecii carriers.

It is well documented that antiphospholipid antibodies are increased in patients with HIV-1 infection and these are most commonly seen in those with Pneumocystis jirovecii pneumonia. Therefore it has been proposed that this could be the cause of its presence. Recently, P. jirovecii subclinical infection has been described in non-immunodeficient patients. We report here our experience concerning the possible relationship between P. jirovecii infection in non-immunocompromized adults and the production of antiphospholipid antibodies. Circulating lupus anticoagulant and IgM anticardiolipin antibodies were negative in all patients. IgG anticardiolipin antibodies were positive in 2 out of 5 (40%) P. jirovecii carriers and 2 out of 10 (20%) subjects with no evidence of pulmonary infection by this microorganism (p=0.4).

Pneumocystis jirovecii in general population.

The possible presence of Pneumocystis among healthy adults was examined by detecting Pneumocystis jirovecii-specific DNA in prospectively obtained oropharyngeal wash samples from 50 persons without underlying lung disease or immunosuppression. Pneumocystis carriage, defined by detecting Pneumocystis DNA by nested polymerase chain reaction in 2 independent analyses plus successful mitochondrial large subunit ribosomal RNA typing by direct sequencing, was found in 20% of cases. All carriers were asymptomatic, anti-HIV negative, and had normal total lymphocyte and CD4+ cell counts. A second sample obtained in the 6-month follow-up was positive in 2 of 9 available carriers. Genotype analysis showed different polymorphisms; 85A/248C (40%) and 85C/248C (30%) were most frequently observed. This study provides the first evidence that P. jirovecii DNA can be frequently detected in the respiratory tract of immunocompetent adults, which agrees with the hypothesis that the general population could be a reservoir and source of this infection.