M. Montes-Cano

Pneumocystis jirovecii multilocus genotyping profiles in patients from Portugal and Spain

Pneumonia caused by the opportunistic organism Pneumocystis jirovecii is a clinically important infection affecting AIDS and other immunocompromised patients. The present study aimed to compare and characterise the frequency pattern of DNA sequences from the P. jirovecii mitochondrial large-subunit rRNA (mtLSU rRNA) gene, the dihydropteroate synthase (DHPS) gene and the internal transcribed spacer (ITS) regions of the nuclear rRNA operon in specimens from Lisbon (Portugal) and Seville (Spain). Total DNA was extracted and used for specific molecular sequence analysis of the three loci. In both populations, mtLSU rRNA gene analysis revealed an overall prevalence of genotype 1. In the Portuguese population, genotype 2 was the second most common, followed by genotype 3. Inversely, in the Spanish population, genotype 3 was the second most common, followed by genotype 2. The DHPS wild-type sequence was the genotype observed most frequently in both populations, and the DHPS genotype frequency pattern was identical to distribution patterns revealed in other European studies. ITS types showed a significant diversity in both populations because of the high sequence variability in these genomic regions. The most prevalent ITS type in the Portuguese population was Eg, followed by Cg. In contrast to other European studies, Bi was the most common ITS type in the Spanish samples, followed by Eg. A statistically significant association between mtLSU rRNA genotype 1 and ITS type Eg was revealed.

Pneumocystis jiroveci isolates with dihydropteroate synthase mutations in patients with chronic bronchitis

Since mutations in the dihydropteroate synthase (DHPS) gene possibly associated with sulfonamide resistance have been reported in patients with Pneumocystis jiroveci (previously carinii) pneumonia, and since P. jiroveci colonization has been recently demonstrated in patients with chronic pulmonary diseases, the present study aimed to investigate the possible occurrence of P. jiroveci DHPS mutations in patients with chronic bronchitis. P. jiroveci colonization was detected in 15 of 37 non-selected patients with chronic bronchitis by amplifying the large subunit of the mitochondrial gene of the ribosomal RNA using nested PCR. DHPS mutations were demonstrated using touchdown PCR and restriction enzyme analysis in two of eight patients with chronic bronchitis and in two of six patients from the same region who had AIDS-associated Pneumocystis pneumonia. In all cases, mutations were observed in subjects with no prior exposure to sulfonamides. These data could have important implications for public health, since (i) P. jiroveci colonization could speed the progression of chronic bronchitis, and (ii) these patients, who are customary sputum producers, could represent a reservoir for sulfonamide-resistant strains with the potential ability to transmit them to immunocompromised hosts susceptible to Pneumocystis pneumonia.

Geographical variation in serological responses to recombinant Pneumocystis jirovecii major surface glycoprotein antigens

The use of recombinant fragments of the major surface glycoprotein (Msg) of Pneumocystis jirovecii has proven useful for studying serological immune responses of blood donors and human immunodeficiency virus (HIV)-positive (HIV(+)) patients. Here, we have used ELISA to measure antibody titres to Msg fragments (MsgA, MsgB, MsgC1, MsgC3, MsgC8 and MsgC9) in sera isolated in the USA (n=200) and Spain (n=326), to determine whether geographical location affects serological responses to these antigens. Blood donors from Seville exhibited a significantly greater antibody titre to MsgC8, and significantly lower responses to MsgC3 and MsgC9, than did Cincinnati (USA) donors. Spanish blood donors (n=162) also exhibited elevated responses to MsgC1, MsgC8 and MsgC9 as compared with Spanish HIV(+) (n=164) patients. HIV(+) patients who had Pneumocystis pneumonia (PcP(+)) exhibited a higher response to MsgC8 than did HIV(+) PcP(-) patients. These data show that geographical location plays a role in responsiveness to Msg fragments. Additionally, these fragments have utility in differentiating HIV(+) PcP and HIV(+) PcP(+) among patient populations.

Association between human-Pneumocystis infection and small-cell lung carcinoma.

Background  Tobacco smoking is the most important but not the only risk factor in lung carcinoma. There is evidence that certain infections, which cause chronic inflammatory reactions, can also induce tumour development. It has recently been shown that patients with chronic pulmonary diseases present a high rate of subclinical Pneumocystis infection, and that the latter is able to induce inflammatory responses and alveolar cell alterations. The possible role of Pneumocystis infection in the development of lung neoplasms thus deserves consideration.

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.