Control tactics and evaluation of clinical efficacy of therapy in children with bronchial asthma associated with mycoplasma infection

The uncontrolled course of bronchial asthma (BA) in children and insufficient efficacy of standard therapy regimens may be due to underestimated infectious factors. The objective: to study specific parameters of the course and treatment of mycoplasma infection, improve monitoring over BA therapy in children of the tender and preschool age. Subjects and methods. 320 children with BA in the age from 1 to 7 years old were followed up. In this work, Mycoplasma pneumoniae (FH), Mycoplasma hominis (H-34), Ureaplasma urealyticum (serotype 8), Mycoplasma fermentans (PG18) and Mycoplasma arthritidis (PG6) were used, they were cultured on a liquid medium for cultivation of mycoplasmas and ureaplasmas. To isolate CIC from blood serum samples, we used the method of precipitation with 3.5% polyethylene glycol (PEG, 6000 Da), hemagglutination assays and IFA were used to identify mycoplasma antigens, mycoplasma DNA was detected by PCR with InterLabService diagnostic kits. The data of 47 patients with prolonged mycoplasma antigenemia were assessed at the baseline and in 1.5-3 months after the treatment course of azithromycin.Results. 320 blood serum samples from children with BA were tested, and the detection rate by hemagglutination assays of M. pneumoniae antigens was 60.9%, M. hominis – 43.4%, U. urealyticum – 44.8%, M. arthritidis – 29.7%, M. fermentrans – 45.3%. The assessment of relationship between of M. pneumoniae, M. hominis and asthma exacerbation showed that antigens of M. pneumoniae and M. hominis were found in 216 children (single or associated). After treatment with azithromycin, the frequency of BA exacerbations within 3 months decreased by 2.4 times, as well as there was a reduction in the number of samples positive for antigens and DNA of mycoplasma in a free state and within CIC. The persistence of antigens, DNA of M. pneumoniae and M. hominis before treatment of 47 children was 80.9 and 66.0% of cases, after treatment with azithromycin – 31.9 and 25.5% of cases, respectively (p < 0.001). Within CIC isolated from the blood serum of patients, antigens to M. pneumoniae and M. hominis before treatment were detected by IFA in 63.8 and 70.2% of children, after treatment – in 31.9 and 23.4%, respectively. p < 0.001. In blood samples, DNA of M. pneumoniae and M. hominis was detected by PCR before treatment in 8.5 and 34.0%; after treatment in 6.4% (p = 0.318) and 19.1% of cases, respectively (p = 0.009), and within CIC isolated from blood serum, in 27.7 and 48.9% of cases before treatment and 8.5 and 34.0% after it, respectively (p = 0.009).

Visualisation and biovolume quantification in the characterisation of biofilm formation in Mycoplasma fermentans

The ability of mycoplasmas to persist on surfaces has been widely acknowledged, despite their fastidious nature. However, the organism’s capability to form a recognisable biofilm structure has been identified more recently. In the current study Mycoplasma fermentans was found to adhere to the glass surface forming highly differentiated biofilm structures. The volumes of biofilm microcolonies were quantified and observed to be greater at late growth stage than those at early growth stage. The channel diameters within biofilms were measured with Scanning Electron Microscopy images and found to be consistent with the size observed in Confocal Laser Scanning Microscope images. The combination of imaging methods with 3D visualisation provides key findings that aid understanding of the mycoplasma biofilm formation and true biofilm architecture. The observations reported here provide better understanding of the persistence of these minimalist pathogens in nature and clinical settings.

Analysis of DnaK Expression from a Strain of Mycoplasma fermentans in Infected HCT116 Human Colon Carcinoma Cells

Several species of mycoplasmas, including Mycoplasma fermentans, are associated with certain human cancers. We previously isolated and characterized in our laboratory a strain of human mycoplasma M. fermentans subtype incognitus (MF-I1) able to induce lymphoma in a Severe Combined Immuno-Deficient (SCID) mouse model, and we demonstrated that its chaperone protein, DnaK, binds and reduces functions of human poly-ADP ribose polymerase-1 (PARP1) and ubiquitin carboxyl-terminal hydrolase protein-10 (USP10), which are required for efficient DNA repair and proper p53 activities, respectively. We also showed that other bacteria associated with human cancers (including Mycoplasmapneumoniae, Helicobacterpylori, Fusobacteriumnucleatum, Chlamydiathrachomatis, and Chlamydia pneumoniae) have closely related DnaK proteins, indicating a potential common mechanism of cellular transformation. Here, we quantify dnaK mRNA copy number by RT-qPCR analysis in different cellular compartments following intracellular MF-I1 infection of HCT116 human colon carcinoma cells. DnaK protein expression in infected cells was also detected and quantified by Western blot. The amount of viable intracellular mycoplasma reached a steady state after an initial phase of growth and was mostly localized in the cytoplasm of the invaded cells, while we detected a logarithmically increased number of viable extracellular bacteria. Our data indicate that, after invasion, MF-I1 is able to establish a chronic intracellular infection. Extracellular replication was more efficient while MF-I1 cultured in cell-free axenic medium showed a markedly reduced growth rate. We also identified modifications of important regulatory regions and heterogeneous lengths of dnaK mRNA transcripts isolated from intracellular and extracellular MF-I1. Both characteristics were less evident in dnaK mRNA transcripts isolated from MF-I1 grown in cell-free axenic media. Taken together, our data indicate that MF-I1, after establishing a chronic infection in eukaryotic cells, accumulates different forms of dnaK with efficient RNA turnover.

Determination of metabolic activity in planktonic and biofilm cells of Mycoplasma fermentans and Mycoplasma pneumoniae by nuclear magnetic resonance

Mycoplasmas are fastidious microorganisms, typically characterised by their restricted metabolism and minimalist genome. Although there is reported evidence that some mycoplasmas can develop biofilms little is known about any differences in metabolism in these organisms between the growth states. A systematic metabolomics approach may help clarify differences associated between planktonic and biofilm associated mycoplasmas. In the current study, the metabolomics of two different mycoplasmas of clinical importance (Mycoplasma pneumoniae and Mycoplasma fermentans) were examined using a novel approach involving nuclear magnetic resonance spectroscopy and principle component analysis. Characterisation of metabolic changes was facilitated through the generation of high-density metabolite data and diffusion-ordered spectroscopy that provided the size and structural information of the molecules under examination. This enabled the discrimination between biofilms and planktonic states for the metabolomic profiles of both organisms. This work identified clear biofilm/planktonic differences in metabolite composition for both clinical mycoplasmas and the outcomes serve to establish a baseline understanding of the changes in metabolism observed in these pathogens in their different growth states. This may offer insight into how these organisms are capable of exploiting and persisting in different niches and so facilitate their survival in the clinical setting.

Mycoplasma fermentans in acute Crohn’s Disease. A preliminary report of a putative aetio-pathogenic agent*

The authors have requested that this preprint be removed from Research Square.

Proteome analysis of Mycoplasma fermentans cultured under aerobic and anaerobic conditions

Background and aims Mycoplasmas are ubiquitous pathogens found not only in humans but also in animals, plants, insects and soil. Though they usually grow better in an aerobic environment, mycoplasmas are also facultative anaerobic microorganisms. Following infection, the transition of a microorganism from a normal environment into an anaerobic one (e.g. dead or dying tissue) may result in production of a higher number of bacterial toxins. The resolution of the bacterial proteome during the aerobic/anaerobic switch could thus allow the identification of potential pathogenic determinants and pathways. Methods We used two-dimensional gel electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization time-of-flight/tandem mass spectroscopy (MALDI-TOF MS/MS) and subsequent mass spectrometric analysis to characterize the liposoluble and hydrosoluble protein fractions of a strain of Mycoplasma fermentans isolated in our lab (MFI), that was cultured under either aerobic or anaerobic conditions. Results We identified the 27 most abundant proteins in the liposoluble fraction and the 30 most abundant proteins in the hydrosoluble fraction and determined their modulation under aerobic and anaerobic growth. By using Protein ANalysis TrougH Evolutionary Relationships (PANTHER) and the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) software analysis tools, we were able to identify, define and organize the function of each protein, as well as to determine the specific interactome. Conclusions Our work provides the first proteome reference map of Mycoplasma fermentans obtained under aerobic and anaerobic growing conditions. These data may help to better understand the mechanisms of pathogenicity of this microorganism and define new diagnostic targets.