Mycoplasma pneumonia and its complications

Diagnostic value of serum LDH in children with refractory Mycoplasma pneumoniae pneumoniae: A systematic review and meta-analysis

Background

To investigate the relationship between serum Lactate dehydrogenase (LDH) and refractory Mycoplasma pneumoniae pneumonia (RMPP) in juvenile individuals.

Methods

Search Chinese databases and English databases. The retrieval time limit is from the establishment of the database to 2022-04-27. And screening and inclusion of relevant diagnostic test literature. The QUADAS-2 method was used to evaluate the quality of the included literature. The random effects model was used to combine sensitivity, specificity, likelihood ratio, diagnostic odds ratio, summary receiver operating characteristic curve, and area under summary receiver operating characteristic curve to evaluate the prediction value of LDH for RMPP. Subgroup analyses were used to explore sources of heterogeneity.

Results

① A total of 29 literatures that met the criteria were included in the study, and the quality of the literature was medium and high, with a total of 702,2 patients. ② The combined sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve of the studies were: 0.75 (95% CI = 0.73-0.76), 0.73 (95% CI = 0.72-0.74), 3.61 (95% CI = 2.86-4.56), 0.30 (95% CI = 0.23-0.39), 13.04 (95% CI = 8.24-20.63), and 0.85(95% CI = 0.82-0.88). ③ The results of subgroup analysis showed that Compared with the subgroup with LDH threshold ≤400 IU/L, the AUC increased from 0.84 (95% CI = 0.80-0.87) to 0.89 (95% CI = 0.86-0.91).

Conclusions

The serum LDH has good accuracy for the diagnosis of RMPP and can serve as a diagnostic marker for RMPP.

Skin and Mucous Membrane Eruptions Associated with Chlamydophila Pneumoniae Respiratory Infections: Literature Review

BACKGROUND

Mycoplasma pneumoniae pneumonia is sometimes associated with skin or mucous membrane eruptions. Available reviews do not address the association of Chlamydophila pneumoniae pneumonia with skin eruptions. We therefore conducted a systematic review of the literature addressing this issue. The National Library of Medicine, Excerpta Medica, and Web of Science databases were employed.

SUMMARY

In two reports, skin lesions and especially urticaria were more common (p < 0.05) in atypical pneumonia caused by C. pneumoniae as compared with M. pneumoniae. We found 47 patients (<18 years, n = 16; ≥18 years, n = 31) affected by a C. pneumoniae atypical pneumonia, which was associated with erythema nodosum, erythema multiforme minus, erythema multiforme majus, isolated mucositis, or cutaneous vasculitis. We also found the case of a boy with C. pneumoniae pneumonia and acute generalized exanthematous pustulosis. We did not find any case of C. pneumoniae respiratory infection associated with either Gianotti-Crosti syndrome, pityriasis lichenoides et varioliformis acuta Mucha-Habermann, or varicella-like skin eruptions.

Development of a replicating plasmid based on the native oriC in Mycoplasma pneumoniae

Bacteria of the genus Mycoplasma have recently attracted considerable interest as model organisms in synthetic and systems biology. In particular, Mycoplasma pneumoniae is one of the most intensively studied organisms in the field of systems biology. However, the genetic manipulation of these bacteria is often difficult due to the lack of efficient genetic systems and some intrinsic peculiarities such as an aberrant genetic code. One major disadvantage in working with M. pneumoniae is the lack of replicating plasmids that can be used for the complementation of mutants and the expression of proteins. In this study, we have analysed the genomic region around the gene encoding the replication initiation protein, DnaA, and detected putative binding sites for DnaA (DnaA boxes) that are, however, less conserved than in other bacteria. The construction of several plasmids encompassing this region allowed the selection of plasmid pGP2756 that is stably inherited and that can be used for genetic experiments, as shown by the complementation assays with the glpQ gene encoding the glycerophosphoryl diester phosphodiesterase. Plasmid-borne complementation of the glpQ mutant restored the formation of hydrogen peroxide when bacteria were cultivated in the presence of glycerol phosphocholine. Interestingly, the replicating plasmid can also be used in the close relative, Mycoplasma genitalium but not in more distantly related members of the genus Mycoplasma. Thus, plasmid pGP2756 is a valuable tool for the genetic analysis of M. pneumoniae and M. genitalium.

Glycerol metabolism and its implication in virulence in Mycoplasma

Glycerol and glycerol-containing compounds such as lipids belong to the most abundant organic compounds that may serve as nutrient for many bacteria. For the cell wall-less bacteria of the genus Mycoplasma, glycerol derived from phospholipids of their human or animal hosts is the major source of carbon and energy. The lipids are first degraded by lipases, and the resulting glycerophosphodiesters are transported into the cell and cleaved to release glycerol-3-phosphate. Alternatively, free glycerol can be transported, and then become phosphorylated. The oxidation of glycerol-3-phosphate in Mycoplasma spp. as well as in related firmicutes involves a hydrogen peroxide-generating glycerol-3-phosphate oxidase. This enzyme is a key player in the virulence of Mycoplasma spp. as the produced hydrogen peroxide is one of the major virulence factors of these bacteria. In this review, the different components involved in the utilization of lipids and glycerol in Mycoplasma pneumoniae and related bacteria are discussed.

Comprehensive bioinformatics analysis of Mycoplasma pneumoniae genomes to investigate underlying population structure and type-specific determinants

Mycoplasma pneumoniae is a significant cause of respiratory illness worldwide. Despite a minimal and highly conserved genome, genetic diversity within the species may impact disease. We performed whole genome sequencing (WGS) analysis of 107 M. pneumoniae isolates, including 67 newly sequenced using the Pacific BioSciences RS II and/or Illumina MiSeq sequencing platforms. Comparative genomic analysis of 107 genomes revealed >3,000 single nucleotide polymorphisms (SNPs) in total, including 520 type-specific SNPs. Population structure analysis supported the existence of six distinct subgroups, three within each type. We developed a predictive model to classify an isolate based on whole genome SNPs called against the reference genome into the identified subtypes, obviating the need for genome assembly. This study is the most comprehensive WGS analysis for M. pneumoniae to date, underscoring the power of combining complementary sequencing technologies to overcome difficult-to-sequence regions and highlighting potential differential genomic signatures in M. pneumoniae.

Two case reports: Whole genome sequencing of two clinical macrolide-resistant Mycoplasma pneumoniae isolates with different responses to azithromycin

BACKGROUND

Cases of macrolide-resistant Mycoplasma pneumoniae have increased rapidly since 2000, especially in Asia. Patients infected with macrolide-resistant M pneumoniae usually present with severe M pneumoniae pneumonia. The aim of this study was to identify indicators for whether children at an early stage of M pneumoniae infection develop mild or severe pneumonia.

CASE SUMMARY

Herein, we retrospectively reviewed 2 pediatric cases caused by macrolide-resistant M pneumoniae, but with markedly different severity of pneumonia. First, we compared the clinical courses of the patients, then isolated the pathogens and tested their response to macrolides, then finally, carried out whole genome sequencing of these isolates. Despite the difference in clinical presentation of the infection, both isolates exhibited a high level of resistance to macrolide antibiotics. Analysis of clinical data showed that the erythrocyte sedimentation rate in blood samples of the patients in the early stages of disease varied greatly. Genome sequence analysis revealed single nucleotide polymorphisms mainly focused on adhesin P1, which is involved in the pathogenicity of M pneumoniae.

CONCLUSION

The differences of erythrocyte sedimentation rate in the early stage of M pneumoniae pneumonia and mutations in P1 protein may help us to distinguish between severe or mild disease after infection with macrolide-resistant M pneumoniae. These findings could lead to the development of screening assays that will allow us to distinguish severe or mild M pneumoniae pneumonia early.

Is There any Relationship Between Extra-Pulmonary Manifestations of Mycoplasma Pneumoniae Infection and Atopy/Respiratory Allergy in Children?

Mycoplasma pneumoniae is a common cause of respiratory infections in children, but sometimes extra-pulmonary diseases can be observed. The immunological mechanisms involved in these extra-respiratory complications are unknown. Here, we report a small case series of Mycoplasma-related diseases including 5 children who developed: i) aseptic meningitis; ii) urticarial rash and pericardial effusion; iii) pleural effusion with severe eosinophilia; iv) Stevens-Johnson syndrome; v) multiform erythema. Interestingly, all children were moderately to highly atopic, as a common immunologic feature.

Comparative "-omics" in Mycoplasma pneumoniae Clinical Isolates Reveals Key Virulence Factors

The human respiratory tract pathogen M. pneumoniae is one of the best characterized minimal bacterium. Until now, two main groups of clinical isolates of this bacterium have been described (types 1 and 2), differing in the sequence of the P1 adhesin gene. Here, we have sequenced the genomes of 23 clinical isolates of M. pneumoniae. Studying SNPs, non-synonymous mutations, indels and genome rearrangements of these 23 strains and 4 previously sequenced ones, has revealed new subclasses in the two main groups, some of them being associated with the country of isolation. Integrative analysis of in vitro gene essentiality and mutation rates enabled the identification of several putative virulence factors and antigenic proteins; revealing recombination machinery, glycerol metabolism and peroxide production as possible factors in the genetics and physiology of these pathogenic strains. Additionally, the transcriptomes and proteomes of two representative strains, one from each of the two main groups, have been characterized to evaluate the impact of mutations on RNA and proteins levels. This study has revealed that type 2 strains show higher expression levels of CARDS toxin, a protein recently shown to be one of the major factors of inflammation. Thus, we propose that type 2 strains could be more toxigenic than type 1 strains of M. pneumoniae.

Neutrophil dependence of vascular remodeling after Mycoplasma infection of mouse airways

Vascular remodeling is a feature of sustained inflammation in which capillaries enlarge and acquire the phenotype of venules specialized for plasma leakage and leukocyte recruitment. We sought to determine whether neutrophils are required for vascular remodeling in the respiratory tract by using Mycoplasma pulmonis infection as a model of sustained inflammation in mice. The time course of vascular remodeling coincided with the influx of neutrophils during the first few days after infection and peaked at day 5. Depletion of neutrophils with antibody RB6-8C5 or 1A8 reduced neutrophil influx and vascular remodeling after infection by about 90%. Similarly, vascular remodeling after infection was suppressed in Cxcr2(-/-) mice, in which neutrophils adhered to the endothelium of venules but did not extravasate into the tissue. Expression of the venular adhesion molecule P-selectin increased in endothelial cells from day 1 to day 3 after infection, as did expression of the Cxcr2-receptor ligands Cxcl1 and Cxcl2. Tumor necrosis factor α (TNFα) expression increased more than sixfold in the trachea of wild-type and Cxcr2(-/-) mice, but intratracheal administration of TNFα did not induce vascular remodeling similar to that seen in infection. We conclude that neutrophil influx is required for remodeling of capillaries into venules in the airways of mice with Mycoplasma infection and that TNFα signaling is necessary but not sufficient for vascular remodeling.

Fulminant and Fatal Multiple Organ Failure in a 12-Year-Old Boy With Mycoplasma pneumoniae Infection

Mycoplasma pneumoniae (Mp) is a unique pathogen that causes not only pulmonary but also extrapulmonary manifestations that must be rapidly diagnosed. A 12-year-old boy, with no relevant medical history, presented with fever, severe epigastric pain, and vomiting. Laboratory findings showed fulminant and cholestatic hepatitis, hemolytic anemia, thrombocytopenia, acute kidney injury, disseminated intravascular coagulopathy, acute myocardial infarction, and rhabdomyolysis. His clinical condition rapidly deteriorated during intubation and continuous renal replacement therapy. Despite intensive treatment, he did not recover. We report a case of fulminant and fatal multiple organ failure in a previously healthy boy with Mp infection, describing the possible pathomechanisms of multiple organ failure involved in the disease.