Mycoplasma invasion into host cells: An integrated model of infection strategy.

Mycoplasma belong to the genus Mollicutes and are notable for their small genome sizes (500-1300 kb) and limited biosynthetic capabilities. They exhibit pathogenicity by invading various cell types to survive as intracellular pathogens. Adhesion is a crucial prerequisite for successful invasion and is orchestrated by the interplay between mycoplasma surface adhesins and specific receptors on the host cell membrane. Invasion relies heavily on clathrin- and caveolae-mediated internalization, accompanied by multiple activated kinases, cytoskeletal rearrangement, and a myriad of morphological alterations, such as membrane invagination, nuclear hypertrophy and aggregation, cytoplasmic edema, and vacuolization. Once mycoplasma successfully invade host cells, they establish resilient sanctuaries in vesicles, cytoplasm, perinuclear regions, and the nucleus, wherein specific environmental conditions favor long-term survival. Although lysosomal degradation and autophagy can eliminate most invading mycoplasmas, some viable bacteria can be released into the extracellular environment via exocytosis, a crucial factor in the prolonging infection persistence. This review explores the intricate mechanisms by which mycoplasma invades host cells and perpetuates their elusive survival, with the aim of highlighting the challenge of eradicating this enigmatic bacterium.

Mycoplasma DnaK increases DNA copy number variants in vivo.

The human microbiota affects critical cellular functions, although the responsible mechanism(s) is still poorly understood. In this regard, we previously showed that Mycoplasma fermentans DnaK, an HSP70 chaperone protein, hampers the activity of important cellular proteins responsible for DNA integrity. Here, we describe a novel DnaK knock-in mouse model generated in our laboratory to study the effect of M. fermentans DnaK expression in vivo. By using an array-based comparative genomic hybridization assay, we demonstrate that exposure to DnaK was associated with a higher number of DNA copy number variants (CNVs) indicative of unbalanced chromosomal alterations, together with reduced fertility and a high rate of fetal abnormalities. Consistent with their implication in genetic disorders, one of these CNVs caused a homozygous Grid2 deletion, resulting in an aberrant ataxic phenotype that recapitulates the extensive biallelic deletion in the Grid2 gene classified in humans as autosomal recessive spinocerebellar ataxia 18. Our data highlight a connection between components of the human urogenital tract microbiota, namely Mycoplasmas, and genetic abnormalities in the form of DNA CNVs, with obvious relevant medical, diagnostic, and therapeutic implications.

Downregulated mitochondrial transcription factor A enhances mycoplasma infection to promote the metastasis of hepatocellular carcinoma.

Mycoplasma is widespread in various hosts and may cause various diseases in animals. Interestingly, the occurrence of mycoplasma infection was observed in many tumor types. However, the mechanism regulating its infection is far from clear. We unexpectedly found that the knockdown of mitochondrial transcription factor A (TFAM) remarkably enhanced mycoplasma infection in hepatocellular carcinoma (HCC) cells. More importantly, we found that mycoplasma infection facilitated by TFAM knockdown significantly promoted HCC cell metastasis. Mycoplasma infection was further found to be positively correlated with poor prognosis in patients with HCC. Mechanistically, the decreased TFAM expression upregulated the transcription factor Sp1 to increase the expression level of Annexin A2 (ANXA2), which was reported to interact with membrane protein of mycoplasma. Moreover, we found that mycoplasma infection enhanced by the TFAM downregulation promoted HCC migration and invasion by activating the nuclear factor-κB signaling pathway. The downregulation of TFAM enhanced mycoplasma infection in HCC cells and promoted HCC cell metastasis. Our study contributes to the understanding of the pathological role of mycoplasma infection and provides supporting evidence that targeting TFAM could be a potential strategy for the treatment of HCC with mycoplasma infection.

Genetic Polymorphisms in MicroRNA-196a2 and the Risk of Human Abortion Related to Mycoplasma hominis.

Mutations in some miRNAs are associated with human recurrent pregnancy loss (RPL). In parallel, Mycoplasma spp. are one of the most common infections in pregnant women. The objective of this study was to identify the relationship between miRNA196a-2 gene polymorphism and Mycoplasma hominis (M. hominis) infection as a possible cause of human abortion. A total of 160 cervical swab specimens were collected from women (80 samples with at least one abortion as case, and 80 samples without abortion as control). A PCR-based method using 16S rRNA gene and tetra primer amplification refractory mutation system-polymerase chain (Tetra-ARMS-PCR) were used to identify the presence of M. hominis infections and miRNA196a-2 genotypes of studied women, respectively. Results showed that 22.5% of women with abortion and 7.5% of women without abortion were infected with M. hominis, thereby suggesting a significant difference between the two groups (P < 0.05). Tetra-ARMSPCR indicated that no significant difference in frequency of genotypes existed between women experimenting abortion and control group. Independently to the presence of M. hominis infection, a significant difference (P < 0.05) was observed in genotypic frequencies of miRNA196a-2 between RPL women and those with one abortion. Estimation of the Odds Ratios indicated that the chance of recurrent abortions in TT genotypes of miRNA196a-2 was about three times more likely than CC in non-infected individuals and about five times more likely than CC in M. hominis-infected patients. Our results proposed the role of miRNA196a-2 genotypes in RPL either in M. hominis-infected or non-infected individuals.

Mycoplasma gallisepticum induced exosomal gga-miR-193a to disturb cell proliferation, apoptosis, and cytokine production by targeting the KRAS/ERK signaling pathway.

Mycoplasma gallisepticum (MG) is the main pathogen of chronic respiratory disease (CRD), an infectious disease in chickens with high morbidity. Exosomal miRNAs are emerging as important regulators in host immune response to microbial invasion. Previously, we found that gga-miR-193a was significantly up-regulated in exosomes from MG-infected primary chicken type II pneumocytes (CP-IIs). Therefore, the purpose of this study was to investigate the role of exosomal gga-miR-193a in MG infection. Exosomes were isolated and identified via ultracentrifugation, transmission electron microscopy, and nanoparticle-tracking analysis. Real-time quantitative PCR and Western blot were used to detect the gene expression. Enzyme-linked immunosorbent assay was used to examine the levels of the inflammatory cytokines. CCK-8 and flow cytometry assays were applied to analyze the cell functions. The results showed that MG infection induced high expression of gga-miR-193a in exosomes from CP-IIs. Moreover, exosomes secreted by MG-infected CP-IIs could selectively transport gga-miR-193a into DF-1 cells. Exosomal gga-miR-193a internalized by DF-1 cells inhibited cell proliferation, promoted apoptosis, and increased interleukin-1ß and tumor necrosis factor-α secretions by targeting the RAS/ERK signaling pathway. These results suggest that MG induced the secretion of gga-miR-193a by exosomes to damage the life activities of normal cells, which partially interpreted the mechanism of MG establishing systemic chronic infection in the body.

Lnc90386 Sponges miR-33-5p to Mediate Mycoplasma gallisepticum-Induced Inflammation and Apoptosis in Chickens via the JNK Pathway.

Mycoplasma gallisepticum (MG) is one of the most important pathogens, that causes chronic respiratory disease (CRD) in chickens. Long non-coding RNAs (lncRNAs) are emerging as new regulators for many diseases and some lncRNAs can function as competing endogenous RNAs (ceRNAs) to regulate mRNAs by competitively binding to miRNAs. Here, we found that miR-33-5p was significantly up-regulated both in MG-infected chicken embryonic lungs and chicken embryo fibroblast cells (DF-1), and Lnc90386 negatively correlated with miR-33-5p. miR-33-5p, as a new regulator for MG infection, repressed apoptosis, inflammatory factors in DF-1 cells by targeting JNK1. Further analyses showed that Lnc90386 sponged miR-33-5p to weaken its inhibitory effect on JNK1, forming the ceRNA regulatory network. Furthermore, knockdown of Lnc90386 significantly inhibited apoptosis and inflammatory factors, and promoted DF-1 cells proliferation. However, co-treatment with miR-33-5p inhibitor and Lnc90386 siRNA showed that knockdown of Lnc90386 could partially eliminate the inhibiting effect of miR-33-5p inhibitor on inflammation, cell apoptosis and proliferation. In conclusion, Lnc90386 sponges miR-33-5p to defend against MG infection by inhibiting the JNK signaling pathway.

gga-miR-142-3p negatively regulates Mycoplasma gallisepticum (HS strain)-induced inflammatory cytokine production via the NF-κB and MAPK signaling by targeting TAB2.

OBJECTIVE: Mycoplasma gallisepticum (MG), a notorious avian pathogen, leads to considerable economic losses in the poultry industry. MG infection is characterized by severe, uncontrollable inflammation and host DNA damage. Micro ribonucleic acids (miRNAs) have emerged as important regulators in microbial pathogenesis. However, the role of miRNAs in MG infection is poorly characterized. In this study, we validated the functional roles of gga-miR-142-3p. METHODS: The relative expression of gga-miR-142-3p in the lungs of the MG-infected chicken embryos and the MG-infected chicken embryonic fibroblast cell line (DF-1) was determined by reverse transcription quantitative real-time PCR analysis. Bioinformatics database was used to analysis the target gene of gga-miR-142-3p. The luciferase reporter assay as well as gene expression analysis were conducted to validate the target gene. To further explore the biological functions of gga-miR-142-3p upon MG infection, the cell proliferation was quantified using Cell Counting Kit-8 (CCK-8). Meanwhile, cell cycle analysis and apoptosis were measured using a flow cytometer. RESULTS: gga-miR-142-3p was significantly upregulated in both MG-infected chicken-embryo lungs and the DF-1 cells. gga-miR-142-3p over expression significantly downregulated the expression of pro-inflammatory cytokines, including interleukin-1ß, interleukin-6 and tumor necrosis factor alpha after MG infection. Meanwhile, gga-miR-142-3p enhanced the host defense against MG infection by facilitating cell proliferation, promoting cell progression and inhibiting cell apoptosis. Interestingly, TAB2 knockdown groups show similar results, whereas, TAB2 over-expression groups and gga-miR-142-3p inhibitor groups had thoroughly opposite results. The expression of p-p65 in nuclear factor kappa B (NF-κB) and p-p38 in the mitogen-activated protein kinase (MAPK) pathway was decreased when gga-miR-142-3p was over-expressed. CONCLUSION: Upon MG infection, upregulation of gga-miR-142-3p alleviates inflammation by negatively regulating the signaling pathways of NF-κB and MAPKs by targeting TAB2 and facilitates cell proliferation by inhibiting cell apoptosis and promoting cell cycle progression to defend against MG infection.

Innate immune response in bovine neutrophils stimulated with Mycoplasma bovis.

Mycoplasma bovis (M. bovis) is a significant worldwide pathogen of cattle. Neutrophils have an important role in the innate immune response during infection with M. bovis. However, even though neutrophils accumulate in M. bovis infection, the interaction of M. bovis and neutrophils has not been fully elucidated. We attempted to elucidate the innate immune response of neutrophils stimulated with M. bovis and evaluate the transcriptome and functional analysis of bovine neutrophils stimulated with M. bovis. Proinflammatory cytokines, such as inducible nitric oxide (iNOS), which was the most increased gene in transcriptome analysis, were increased in quantitative polymerase chain reaction analysis of bovine neutrophils stimulated with live or heat-killed M. bovis. Nitric oxide and intracellular reactive oxygen species production of neutrophils stimulated with M. bovis was significantly increased. Neutrophils stimulated with M. bovis showed an increased ratio of nonapoptotic cell death compared to unstimulated controls. We demonstrated that neutrophil extracellular traps (NETs) formation was not recognized in neutrophils stimulated with live M. bovis. However, heat-killed M. bovis induced NETs formation. We also showed the interaction with M. bovis and bovine neutrophils regarding proinflammatory cytokine gene expression and functional expression related to NETs formation. Live and killed M. bovis induced innate immune responses in neutrophils and had the potential to induce NETs formation, but live M. bovis escaped NETs.

Novel Secreted Protein of Mycoplasma bovis MbovP280 Induces Macrophage Apoptosis Through CRYAB.

Mycoplasma bovis causes important diseases and great losses on feedlots and dairy farms. However, there are only a few measures to control M. bovis-related diseases. As in other mycoplasma species, this is predominantly because the virulence related factors of this pathogen are largely unknown. Therefore, in this study, we aimed to identify novel virulence-related factors among the secreted proteins of M. bovis. Using bioinformatic tools to analyze its secreted proteins, we preliminarily predicted 39 secreted lipoproteins, and then selected 11 of them for confirmation based on SignalP scores >0.6 or SceP scores >0.8 and conserved domains. These 11 genes were cloned after gene modification based on the codon bias of Escherichia coli and expressed. Mouse antiserum to each recombinant protein was developed. A western blotting assay with these antisera confirmed that MbovP280 and MbovP475 are strongly expressed and secreted proteins, but only MbovP280 significantly reduced the viability of bovine macrophages (BoMac). In further experiments, MbovP280 induced the apoptosis of BoMac treated with both live M. bovis and MbovP280 protein. The conserved coiled-coil domain of MbovP280 at amino acids 210-269 is essential for its induction of apoptosis. Further, immunoprecipitation, mass spectrometry, and coimmunoprecipitation assays identified the anti-apoptosis regulator αB-crystallin (CRYAB) as an MbovP280-binding ligand. An αß-crystallin knockout cell line BoMac-cryab-, Mbov0280-knockout M. bovis strain T9.297, and its complemented M. bovis strain CT9.297 were constructed and the apoptosis of BoMac-cryab- induced by these strains was compared. The results confirmed that CRYAB is critical for MbovP280 function as an apoptosis inducer in BoMac. In conclusion, in this study, we identified MbovP280 as a novel secreted protein of M. bovis that induces the apoptosis of BoMac via its coiled-coil domain and cellular ligand CRYAB. These findings extend our understanding of the virulence mechanism of mycoplasmal species.

Mycoplasma hyorhinis infection promotes tyrosine kinase inhibitor (TKI) resistance in lung adenocarcinoma patients.

PURPOSE: To explore the relationship between Mycoplasma hyorhinis infection and tyrosine kinase inhibitor (TKI) resistance in lung adenocarcinoma patients. METHODS: Mycoplasma hyorhinis infection can be verified with the monoclonal antibody PD4, which specifically recognizes a distinct protein of M. hyorhinis. Immunohistochemistry (IHC), using PD4 to detect M. hyorhinis, was performed on paraffin-embedded lung adenocarcinoma tissues of patients who had epidermal growth factor (EGFR) mutations and had received oral TKI. The number of patients enrolled in our study was 101. Assessments following TKI treatment were performed until objective disease progression or stable disease at the cutoff date was reached. In all of the patients, the primary endpoint was investigator-assessed progression-free survival (PFS). RESULTS: Immunohistochemistry revealed that 61 of 101 cases (60.4%) of lung adenocarcinoma were positive for M. hyorhinis, which comprised of 31 low-positive cases and 30 high-positive cases; the remaining 40 cases (39.6%) were negative. The median PFS was significantly longer in the negative group [18 months (95% CI 14.15-21.85)] than in the low-positive group [10 months (95% CI 7.70-12.30); hazard ratio (HR) 4.095, 95% CI 2.254-7.438; p < 0.001] and in the high-positive group [4 months (95% CI 2.85-5.15); HR 31.703, 95% CI 14.425-69.678; p < 0.001]. The results of the subgroup analysis were satisfactory. The PFS benefit with negative M. hyorhinis infection was consistent across subgroups. CONCLUSIONS: In this retrospective, exploratory analysis, M. hyorhinis infection significantly reduced PFS. With increased levels of M. hyorhinis infection, the progression of the disease was more advanced, likely due to the hydrolysis of TKI by M. hyorhinis. A strong correlation was found between M. hyorhinis infection and TKI resistance in lung adenocarcinoma. This study provides potent evidence that M. hyorhinis hydrolyses TKI and will assist in the research of related mechanisms in the future. IMPLICATIONS FOR CANCER SURVIVORS: It provides an option to improve the efficacy of TKI, including strategies to decrease M. hyorhinis infection, thereby reducing long-term distress in TKI resistance patients with EGFR mutations.

An alarming high prevalence of resistance-associated mutations to macrolides and fluoroquinolones in Mycoplasma genitalium in Belgium: results from samples collected between 2015 and 2018.

OBJECTIVES: The number of reported cases of multiresistant Mycoplasma genitalium (MG) is increasing globally. The aim of this study was to estimate the prevalence of macrolide and possible fluoroquinolone resistance-associated mutations (RAMs) of MG in Belgium. METHODS: The study was performed retrospectively on two sets of MG-positive samples collected in Belgium between 2015 and 2018. The first set of samples originated from routine surveillance activities and the second set came from a cohort of men who have sex with men (MSM) using pre-exposure prophylaxis to prevent HIV transmission. Detection of RAMs to macrolides and fluoroquinolones was performed on all samples using DNA sequencing of the 23S ribosomal RNA gene, the gyrA gene and the parC gene. RESULTS: Seventy-one per cent of the MG samples contained a mutation conferring resistance to macrolides or fluoroquinolones (ParC position 83/87). RAMs were more frequently found among men compared with women for fluoroquinolones (23.9% vs 9.1%) and macrolides (78.4% vs 27.3%). Almost 90% of the MG infections among MSM possessed a RAM to macrolides (88.4%). In addition, 18.0% of the samples harboured both macrolides and fluoroquinolone RAMs; 3.0% in women and 24.2% in MSM. Being MSM was associated with macrolide RAMs (OR 15.3), fluoroquinolone RAMs (OR 3.8) and having a possible multiresistant MG infection (OR 7.2). CONCLUSION: The study shows an alarmingly high prevalence of MG with RAMs to macrolides and fluoroquinolones in Belgium. These results highlight the need to improve antimicrobial stewardship in Belgium in order to avoid the emergence of untreatable MG.

Sequence variation and immunogenicity of the Mycoplasma genitalium MgpB and MgpC adherence proteins during persistent infection of men with non-gonococcal urethritis.

Mycoplasma genitalium is a sexually transmitted bacterial pathogen that infects men and women. Antigenic variation of MgpB and MgpC, the immunodominant adherence proteins of M. genitalium, is thought to contribute to immune evasion and chronic infection. We investigated the evolution of mgpB and mgpC sequences in men with non-gonococcal urethritis persistently infected with M. genitalium, including two men with anti-M. genitalium antibodies at enrollment and two that developed antibodies during follow-up. Each of the four patients was persistently infected with a different strain type and each patient produced antibodies targeting MgpB and MgpC. Amino acid sequence evolution in the variable regions of MgpB and MgpC occurred in all four patients with changes observed in single and multiple variable regions over time. Using the available crystal structure of MgpC of the G37 type strain we found that predicted conformational B cell epitopes localize predominantly to the variable region of MgpC, amino acids that changed during patient infection lie in these epitopes, and variant amino acids are in close proximity to the conserved sialic acid binding pocket. These findings support the hypothesis that sequence variation functions to avoid specific antibodies thereby contributing to persistence in the genital tract.

Azithromycin, minocycline, moxifloxacin and spectinomycin failure in a case with persistent Mycoplasma genitalium infection in Guangzhou, China.

We report a case of Mycoplasma genitalium-positive non-gonococcal urethritis who failed to respond to multiple different courses of antibiotics including azithromycin, minocycline, moxifloxacin and spectinomycin. Extracted M. genitalium DNA from urethral swabs obtained from the patient harbored mutations of 23S rRNA, parC and gyrA. Microbiological cure was eventually achieved by a 14-day course of doxycycline.

Impacts of Mycoplasma loads and lung lesions on immune and hematological statuses of pigs in an eight-breed cross heterogeneous population.

Developments of pulmonary diseases, often accompanied by infections of bacteria, severely affect the meat production and welfare of pigs. This study investigated 307 pigs at age of 240 d from an eight-breed cross reared under standardized housing conditions for associations among the extent of lung lesions, bacteria load inferred from 16S rRNA sequencing of bronchoalveolar lavage fluid, as well as 57 immune cells and 25 hematological traits. We showed that the pigs under study suffered substantial and varied lung lesions, and the Mycoplasma is the most associated bacteria genera. At a false discovery rate of 0.05 (FDR < 0.05), the severity of lung lesions were significantly associated with greater CD8+ to CD3+ cell ratio, neutrophil-to-lymphocyte ratio (NLR), and standard deviation of red blood cell volume distribution width (RDW-SD), and lower CD4-CD8-/CD3+, CD3+CD4-CD8-/PBMCs (peripheral blood mononuclear cells) and CD14-CD16-/PBMCs cell ratios, mean corpuscular hemoglobin concentration, lymphocyte count, and lymphocyte count percentage, reflecting an status of inflammation, immune suppression, and hypoxia of the pigs accompanying the progression of the lung lesions. The Mycoplasma abundance showed positive correlations with neutrophil count, neutrophil count percentage, NLR, monocyte count, coefficient of variation in red blood cell volume distribution width , and RDW-SD, and negative correlations with mean corpuscular hemoglobin concentration, lymphocyte count, and lymphocyte count percentage; these correlations are largely consistent with those of lung lesions, supporting the comorbidity of lung lesions and Mycoplasma infection. We also observed nonlinear associations that sharp increases in neutrophil count and neutrophil count percentage occurred only when Mycoplasma abundance raised above the population-average level. The results provide helpful insights into the changes of host immune status in response to Mycoplasma relevant lung diseases in pigs.

The Lipocalin2 Gene is Regulated in Mammary Epithelial Cells by NFκB and C/EBP In Response to Mycoplasma.

Lcn2 gene expression increases in response to cell stress signals, particularly in cells involved in the innate immune response. Human Lcn2 (NGAL) is increased in the blood and tissues in response to many stressors including microbial infection and in response to LPS in myeloid and epithelial cells. Here we extend the microbial activators of Lcn2 to mycoplasma and describe studies in which the mechanism of Lcn2 gene regulation by MALP-2 and mycoplasma infection was investigated in mouse mammary epithelial cells. As for the LPS response of myeloid cells, Lcn2 expression in epithelial cells is preceded by increased TNFα, IL-6 and IκBζ expression and selective reduction of IκBζ reduces Lcn2 promoter activity. Lcn2 promoter activation remains elevated well beyond the period of exposure to MALP-2 and is persistently elevated in mycoplasma infected cells. Activation of either the human or the mouse Lcn2 promoter requires both NFκB and C/EBP for activation. Thus, Lcn2 is strongly and enduringly activated by mycoplasma components that stimulate the innate immune response with the same basic regulatory mechanism for the human and mouse genes.

Role of Mycoplasma Chaperone DnaK in Cellular Transformation.

Studies of the human microbiome have elucidated an array of complex interactions between prokaryotes and their hosts. However, precise bacterial pathogen-cancer relationships remain largely elusive, although several bacteria, particularly those establishing persistent intra-cellular infections, like mycoplasmas, can alter host cell cycles, affect apoptotic pathways, and stimulate the production of inflammatory substances linked to DNA damage, thus potentially promoting abnormal cell growth and transformation. Consistent with this idea, in vivo experiments in several chemically induced or genetically deficient mouse models showed that germ-free conditions reduce colonic tumor formation. We demonstrate that mycoplasma DnaK, a chaperone protein belonging to the Heath shock protein (Hsp)-70 family, binds Poly-(ADP-ribose) Polymerase (PARP)-1, a protein that plays a critical role in the pathways involved in recognition of DNA damage and repair, and reduces its catalytic activity. It also binds USP10, a key p53 regulator, reducing p53 stability and anti-cancer functions. Finally, we showed that bystander, uninfected cells take up exogenous DnaK-suggesting a possible paracrine function in promoting cellular transformation, over and above direct mycoplasma infection. We propose that mycoplasmas, and perhaps certain other bacteria with closely related DnaK, may have oncogenic activity, mediated through the inhibition of DNA repair and p53 functions, and may be involved in the initiation of some cancers but not necessarily involved nor necessarily even be present in later stages.

Strategy and validation of a consistent and reproducible nucleic acid technique for mycoplasma detection in advanced therapy medicinal products.

Advanced therapy medicinal products (ATMP) are required to maintain their quality and safety throughout the production cycle, and they must be free of microbial contaminations. Among them, mycoplasma contaminations are difficult to detect and undesirable in ATMP, especially for immunosuppressed patients. Mycoplasma detection tests suggested by European Pharmacopoeia are the "culture method" and "indicator cell culture method" which, despite their effectiveness, are time consuming and laborious. Alternative methods are accepted, provided they are adequate and their results are comparable with those of the standard methods. To validate a novel in-house method, we performed and optimized, a real time PCR protocol, using a commercial kit and an automatic extraction system, in which we tested different volumes of matrix, maximizing the detection sensitivity. The results were compared with those obtained with the gold standard methods. From a volume of 10 ml, we were able to recognize all the mycoplasmas specified by the European Pharmacopoeia, defined as genomic copies per colony forming unit ratio (GC/CFU). Our strategy allows to achieve faster and reproducible results when compared with conventional methods and meets the sensitivity and robustness criteria required for an alternative approach to mycoplasmas detection for in-process and product-release testing of ATMP.

Mycoplasma penetrans bacteremia in an immunocompromised patient detected by metagenomic sequencing: a case report.

BACKGROUND: Mycoplasma sp. are well recognized as etiological agents of respiratory and sexually transmitted disease. Mycoplasma penetrans, a species of Mycoplasma sp., has been frequently detected in HIV-positive patients and associated with the progression of HIV-associated disease. To date, there is only a single case report describing M. penetrans as the causative agent of a severe respiratory tract infection in a HIV-negative patient. CASE PRESENTATION: In this report, we describe the case of M. penetrans bacteremia in a HIV-negative, 38-year-old, female, immunocompromised, solid organ transplant patient (combined kidney and pancreas transplantation in 2016), who was admitted to our hospital with anemic uterine bleeding and fever of 38.3 °C. Several hours before her admission at our university hospital, a latex bladder catheter was inserted into her uterus and she complained about fatigue, dizziness and ongoing vaginal bleeding. Laboratory examination showed severe anemia, but microbiological examination was inconspicuous (culture negative vaginal and cervical smears, negative urine culture). Bacterial blood cultures showed a growth signal after 4 h, but microscopic examination with Gram staining and subcultures on different agar media did not identify bacterial pathogens. To identify the bacterial cause of malignancy in the patient, metagenomic sequencing of the blood culture was performed that identified M. penetrans. CONCLUSION: Metagenomic sequencing identified M. penetrans in an immunosuppressed patient with culture-negative bacteremia. Clinicians should be aware of the opportunistic potential of M. penetrans that may cause severe infections in certain vulnerable patient populations and the limitations of culture and Gram staining for confirming the presence of fastidious bacterial pathogens like Mycoplasma spp.

iTRAQ-based proteomic analysis of Mycoplasma bovis NM-28 strain from two generations for vaccine screening.

Mycoplasma bovis is an important pathogenic bacterium affecting cows and cattle. Clinically, an inactivated vaccine of M. bovis is mainly used to prevent infection by this bacterium. The changes that occur in the antigen when M. bovis is continuously passaged in vitro remain unknown. Therefore, we performed an in vitro serial passage of the M. bovis NM-28 strain, which was isolated and identified in our laboratory. An isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics method was used to analyse the differences between generations 3 and 60. Many major membrane proteins or protective antigens reported in the literature did not exhibit changes between these generations. We found an imbalance between growth rate and nutrition in the 60th generation. The proteomics results were verified by western blotting and real-time PCR. Growth curves were also prepared based on colony-forming units (CFUs) between the 3rd and 60th generations. The number of colonies in the 60th generation in the stationary phase was 5 × 109 CFU mL-1, which was 10-fold higher than that in the 3rd generation. The 60th generation of the NM-28 strain can be used as an inactivated vaccine strain of M. bovis to lower production costs compared to use of the 3rd generation.

Calves Infected with Virulent and Attenuated Mycoplasma bovis Strains Have Upregulated Th17 Inflammatory and Th1 Protective Responses, Respectively.

Mycoplasma bovis is a critical bovine pathogen, but its pathogenesis remains poorly understood. Here, the virulent HB0801 (P1) and attenuated HB0801-P150 (P150) strains of M. bovis were used to explore the potential pathogenesis and effect of induced immunity from calves' differential transcriptomes post infection. Nine one-month-old male calves were infected with P1, P150, or mock-infected with medium and euthanized at 60 days post-infection. Calves in P1 group exhibited other clinical signs and pathological changes compared to the other two groups. Transcriptome profiles of peripheral blood mononuclear cells revealed seven and 10 hub differentially expressed genes (DEGs) in P1 and P150 groups compared with mock-infected group, respectively. Then, P1-induced pathogenesis was predicted to be associated with enhanced Th17, and P150-induced immunity with Th1 response and expression of ubiquitination-associated enzymes. Association analysis showed that 14 and 11 DEGs were positively and negatively correlated with pathological changes, respectively. Furthermore, up-regulated expression in molecules critical to differentiation of pathogenic Th17 cells in lung and peripheral blood mononuclear cells in P1 group was validated at RNA and protein levels. The results confirmed virulent and attenuated strains might be associated with biased differentiation of pro-inflammatory pathogenic Th17 and Th1 subsets respectively.