Dataset Information

Clinical severity of Mycoplasma pneumoniae (MP) infection is associated with bacterial load in oropharyngeal secretions but not with MP genotype.

ABSTRACT: BACKGROUND: Disease severity in Mycoplasma pneumoniae (MP) infection could potentially be related to bacterial factors such as MP genotype (MP1 or MP2; distinguished by different adhesions proteins) or bacterial load in airway secretions. We have compared these parameters in patients who were hospitalized for MP pneumonia, with outpatients with mild MP disease. METHODS: MP bacterial load was measured by real-time PCR in 45 in- and outpatients ("clinical study group") in whom MP DNA had been detected in oropharyngeal secretions by PCR. In addition, genotype and phylogenetic relationships were determined. The phylogenetical assessment was done by partial DNA sequencing of the P1 gene on isolates from 33 patients in the clinical study-group where sufficient DNA was available. The assessment was further extended to isolates from 13 MP-positive family members and 37 unselected MP positive patients from the two subsequent years and two different geographical locations. In total 83 strains were molecular characterized. RESULTS: Mean MP loads were significantly higher in 24 hospitalized patients than in 21 outpatients (1600 vs. 170 genomic equivalents/microL, p = 0.009). This difference remained significant after adjustment for age and days between disease onset and sampling. Hospitalized patients also had higher C-reactive protein levels. Mean levels were 188 vs 20 mg/L (p = 0,001). The genotype assessment showed MP genotype 1 in 17 of the 33 sequenced strains from the clinical study-group, and type 2 in 16 of these patients. Within each genotype, sequence differences were minimal. No association between disease severity and MP genotype was observed. In the extended genotype assessment, MP1 was found in similar proportions. In family contacts it was found in 53% and among patients from the two subsequent years 53% and 40%. CONCLUSIONS: A higher MP bacterial load in throat secretions at diagnosis was associated with more advanced respiratory disease in patients, but MP genotype did not influence disease severity. Both MP genotypes co-circulated during recent outbreaks in Sweden.

SUBMITTER: Nilsson AC

PROVIDER: S-EPMC2837002 | biostudies-literature | 2010

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Clinical severity of Mycoplasma pneumoniae (MP) infection is associated with bacterial load in oropharyngeal secretions but not with MP genotype.

Nilsson Anna C AC Björkman Per P Welinder-Olsson Christina C Widell Anders A Persson Kenneth K

BMC infectious diseases 20100225

<h4>Background</h4>Disease severity in Mycoplasma pneumoniae (MP) infection could potentially be related to bacterial factors such as MP genotype (MP1 or MP2; distinguished by different adhesions proteins) or bacterial load in airway secretions. We have compared these parameters in patients who were hospitalized for MP pneumonia, with outpatients with mild MP disease.<h4>Methods</h4>MP bacterial load was measured by real-time PCR in 45 in- and outpatients ("clinical study group") in whom MP DNA ...[more]

PMID: 20184731

Similar Datasets

Project description:Nationwide increases in Mycoplasma pneumoniae pneumonia cases in Japan were reported in 2011, 2012, 2015, and 2016. In this study, we isolated 554 M. pneumoniae strains in 4 areas in Japan (Kanagawa, Okayama, Osaka, and Saitama) between 2006 and 2019, and performed genotyping analysis. More than 80% of the strains isolated in 2011 and 2012 harbored type 1 p1 adhesin gene; however, strains harboring type 2 or its variant p1 gene increased in 2015 and 2016 and dominated after 2017. These findings suggested that a shift in the prevalent genotype of M. pneumoniae clinical strains occurred recently in Japan. More than 90% of the type 1 strains isolated after 2010 harbored macrolide-resistance mutations in their 23S rRNA gene, whereas most type 2 lineage strains had no such mutations. Consequently, the increase in type 2 lineage strains in Japan has reduced the macrolide resistance rate of clinical M. pneumoniae strains. During this analysis, we also identified M. pneumoniae strains carrying a novel variant type 1 p1 gene, and we classified it as type 1b. We then sequenced the genomes of 81 selected M. pneumoniae strains that we collected between 1976 and 2017 in Japan, and compared them with 156 M. pneumoniae genomes deposited in public databases to provide insights into the interpretation of M. pneumoniae genotyping methods, including p1 typing, multiple-locus variable-number tandem repeat analysis (MLVA), multi-locus sequence typing (MLST), and typing by 8 single-nucleotide polymorphism markers (SNP-8). As expected, p1 typing, MLST, and SNP-8 results exhibited good correlation with whole-genome SNP analysis results in terms of phylogenetic relationships; however, MLVA typing results were less comparable to those of the other methods. MLVA may be useful for the discrimination of strains derived from a single outbreak within a limited area; however, is not reliable for classification of strains collected from distantly separated areas at different time points. This study showed the usefulness of genome-based comparison of M. pneumoniae for molecular epidemiology. Genome sequencing of more strains will improve our understanding of global propagation routes of this pathogen and evolutionary aspects of M. pneumoniae strains.

Dataset Information

Clinical severity of Mycoplasma pneumoniae (MP) infection is associated with bacterial load in oropharyngeal secretions but not with MP genotype.

Publications

Clinical severity of Mycoplasma pneumoniae (MP) infection is associated with bacterial load in oropharyngeal secretions but not with MP genotype.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets