Pneumocystis jirovecii haplotypes at the internal transcribed spacers of the rRNA operon in French HIV-negative patients with diverse clinical presentations of Pneumocystis infections

Pneumocystis jirovecii in Patients With Cystic Fibrosis: A Review

Pneumocystis pneumonia (PCP) remains the most frequent AIDS-defining illness in developed countries. This infection also occurs in non-AIDS immunosuppressed patients, e.g., those who have undergone an organ transplantation. Moreover, mild Pneumocystis jirovecii infections related to low pulmonary fungal burden, frequently designated as pulmonary colonization, occurs in patients with chronic pulmonary diseases, e.g., cystic fibrosis (CF). Indeed, this autosomal recessive disorder alters mucociliary clearance leading to bacterial and fungal colonization of the airways. This mini-review compiles and discusses available information on P. jirovecii and CF. It highlights significant differences in the prevalence of P. jirovecii pulmonary colonization in European and Brazilian CF patients. It also describes the microbiota associated with P. jirovecii in CF patients colonized by P. jirovecii. Furthermore, we have described P. jirovecii genomic diversity in colonized CF patients. In addition of pulmonary colonization, it appears that PCP can occur in CF patients specifically after lung transplantation, thus requiring preventive strategies. In other respects, Pneumocystis primary infection is a worldwide phenomenon occurring in non-immunosuppressed infants within their first months. The primary infection is mostly asymptomatic but it can also present as a benign self-limiting infection. It probably occurs in the same manner in CF infants. Nonetheless, two cases of severe Pneumocystis primary infection mimicking PCP in CF infants have been reported, the genetic disease appearing in these circumstances as a risk factor of PCP while the host-pathogen interaction in older children and adults with pulmonary colonization remains to be clarified.

Pneumocystis jirovecii Diversity in Réunion, an Overseas French Island in Indian Ocean

Data on Pneumocystis jirovecii characteristics from the overseas French territories are still scarce whereas numerous data on P. jirovecii genotypes are available for metropolitan France. The main objective of the present study was to identify P. jirovecii multilocus genotypes in patients living in Réunion and to compare them with those identified using the same method in metropolitan France and in French Guiana. Archival P. jirovecii specimens from immunosuppressed patients, 16 living in Réunion (a French island of the Indian ocean), six living in French Guiana (a South-American French territory), and 24 living in Brest (Brittany, metropolitan France) were examined at the large subunit rRNA (mtLSUrRNA) genes, cytochrome b (CYB), and superoxide dismutase (SOD) genes using PCR assays and direct sequencing. A total of 23 multi-locus genotypes (MLG) were identified combining mtLSUrRNA, CYB, and SOD alleles, i.e., six in Reunionese patients, three in Guianese patients, and 15 in Brest patients. Only one MLG (mtLSU1-CYB1-SOD2) was shared by Reunionese and Guianese patients (one patient from each region) whereas none of the 22 remaining MLG were shared by the 3 patient groups. A total of eight MLG were newly identified, three in Réunion and five in Brest. These results that were obtained through a retrospective investigation of a relatively low number of P. jirovecii specimens, provides original and first data on genetic diversity of P. jirovecii in Réunion island. The results suggest that P. jirovecii organisms from Réunion present specific characteristics compared to other P. jirovecii organisms from metropolitan France and French Guiana.

Investigation of nosocomial pneumocystis infections: usefulness of longitudinal screening of epidemic and post-epidemic pneumocystis genotypes

BACKGROUND

Twenty-five patients, of whom 22 were renal transplant recipients, developed Pneumocystis jirovecii infections at the nephrology department of Reims University Hospital (France) from September 2008 to October 2009, whereas only four sporadic cases had been diagnosed in this department over the 14 previous years.

AIM

This outbreak was investigated by analysing patient encounters and P. jirovecii types.

METHODS

A transmission map was drawn up. P. jirovecii typing at DHPS, ITS and mtLSU rRNA sequences was performed in the patients of the cluster (18 patients with Pneumocystis pneumonia (PCP) and seven colonized patients), 10 unlinked control patients (six PCP patients and four colonized patients), as well as 23 other patients diagnosed with P. jirovecii (nine PCP patients and 14 colonized patients) in the same department over a three-year post-epidemic period.

FINDINGS

Eleven encounters between patients harbouring the same types were observed. Three PCP patients and one colonized patient were considered as possible index cases. The most frequent types in the cluster group and the control group were identical. However, their frequency was significantly higher in the first than in the second group (P < 0.01). Identical types were also identified in the post-epidemic group, suggesting a second outbreak due to the same strain, contemporary to a disruption in prevention measures.

CONCLUSIONS

These results provide additional data on the role of both PCP and colonized patients as infectious sources. Longitudinal screening of P. jirovecii types in infected patients, including colonized patients, is required in the investigation of the fungus's circulation within hospitals.

Genotyping of Pneumocystis jirovecii isolates from human immunodeficiency virus-negative patients in China

Pneumocystis jirovecii is a fungus that causes Pneumocystis pneumonia in immuno-compromised patients. To analyze the genetic diversity of P. jirovecii in HIV-negative patients in China, respiratory specimens were obtained from 105 patients who tested PCR-positive for the presence of the P. jirovecii mitochondrial large subunit ribosomal RNA (mtLSU rRNA) between 2011 and 2013. P. jirovecii isolates were genotyped based on the upstream conserved sequence (UCS) of the major surface glycoprotein (MSG) gene and the internal transcribed spacer (ITS) of nuclear rRNA operon. Eighty-one of the 105 isolates showed a positive PCR for the UCS region. We identified six different patterns comprising two, three, four, or five UCS repeats, including 1, 2, 3 (69.14%), 1, 2, 3, 3 (22.22%), 1, 2 (3.7%), 1, 1, (2.47%), 2, 2, 3, 3 (1.23%), and 1, 1, 2, 3, 3 (1.23%). In regard to the ITS region, 58 of the 105 isolates were cloned and sequenced successfully. Six known ITS1 alleles (A, B, DEL1, E, N, and SYD1), two new alleles (designated as BTM3 and BTM4), six known ITS2 alleles (a, b, i, g, h and O) and one new allele (designated as btm6) were observed. A total of 19 P. jirovecii ITS haplotypes were identified. The most frequent type was Bi (25.9%), followed by Ai (13.8%), Eb (10.3%), and SYD1g (6.9%). Among the 58 specimens examined, 49 (84.5%) were found to contain a single type of P. jirovecii, while 9 (15.5%) contained multiple genotypes. A total of 34 allelic profiles were observed in 58 isolates when the two loci were combined with each other. A Fisher's exact test revealed that there was no statistically significant (P=0.330) association between the most frequent UCS and ITS genotypes. An analysis of the phylogenetic relationship between different patient groups identified two major groups based on the sequence variations of concatenated UCS and ITS sequences in 49 isolates. Our results demonstrated the high genetic variability of P. jirovecii in HIV-negative patients in China.

AIDS-related Pneumocystis jirovecii genotypes in French Guiana

The study described Pneumocystis jirovecii (P. jirovecii) multilocus typing in seven AIDS patients living in French Guiana (Cayenne Hospital) and seven immunosuppressed patients living in Brest, metropolitan France (Brest Hospital). Archival P. jirovecii specimens were examined at the dihydropteroate synthase (DHPS) locus using a PCR-RFLP technique, the internal transcribed spacer (ITS) 1 and ITS 2 and the mitochondrial large subunit rRNA (mtLSUrRNA) gene using PCR and sequencing. Analysis of typing results were combined with an analysis of the literature on P. jirovecii mtLSUrRNA types and ITS haplotypes. A wild DHPS type was identified in six Guianese patients and in seven patients from metropolitan France whereas a DHPS mutant was infected in the remaining Guianese patient. Typing of the two other loci pointed out a high diversity of ITS haplotypes and an average diversity of mtLSUrRNA types in French Guiana with a partial commonality of these haplotypes and types described in metropolitan France and around the world. Combining DHPS, ITS and mtLSU types, 12 different multilocus genotypes (MLGs) were identified, 4 MLGs in Guianese patients and 8 MLGs in Brest patients. MLG analysis allows to discriminate patients in 2 groups according to their geographical origin. Indeed, none of the MLGs identified in the Guianese patients were found in the Brest patients and none of the MLGs identified in the Brest patients were found in the Guianese patients. These results show that in French Guiana (i) PCP involving DHPS mutants occur, (ii) there is a diversity of ITS and mtLSUrRNA types and (iii) although partial type commonality in this territory and metropolitan France can be observed, MLG analysis suggests that P. jirovecii organisms from French Guiana may present specific characteristics.

Molecular epidemiology of Pneumocystis jiroveci in human immunodeficiency virus-positive and -negative immunocompromised patients in The Netherlands

Pneumocystis jiroveci infections can cause pneumocystis pneumonia (PCP) or lead to colonization without signs of PCP. Over the years, different genotypes of P. jiroveci have been discovered. Genomic typing of P. jiroveci in different subpopulations can contribute to unravelling the pathogenesis, transmission and spread of the different genotypes. In this study, we wanted to determine the distribution of P. jiroveci genotypes in immunocompetent and immunocompromised patients in The Netherlands and determine the clinical relevance of these detected mutations. A real-time PCR targeting the major surface glycoprotein gene (MSG) was used as a screening test for the presence of P. jiroveci DNA. Samples positive for MSG were genotyped based on the internal transcribed spacer (ITS) and dihydropteroate synthase (DHPS) genes. Of the 595 included bronchoalveolar lavage fluid samples, 116 revealed the presence of P. jiroveci DNA. A total of 52 of the 116 samples were ITS genotyped and 58 DHPS genotyped. The ITS genotyping revealed 17 ITS types, including two types that have not been described previously. There was no correlation between ITS genotype and underlying disease. All ITS- and DHPS-genotyped samples were found in immunocompromised patients. Of the 58 DHPS-genotyped samples, 50 were found to be WT. The other eight samples revealed a mixed genotype consisting of WT and type 1. The majority of the latter recovered on trimethoprim-sulfamethoxazole suggesting no clinical relevance for this mutation.