Macrolide resistance of Mycoplasma pneumoniae in several regions of China from 2013 to 2019.

This paper retrospectively analysed the prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) in some parts of China. Between January 2013 and December 2019, we collected 4,145 respiratory samples, including pharyngeal swabs and alveolar lavage fluid. The highest PCR-positive rate of M. pneumoniae was 74.5% in Beijing, the highest resistance rate was 100% in Shanghai, and Gansu was the lowest with 20%. The highest PCR-positive rate of M. pneumoniae was 74.5% in 2013, and the highest MRMP was 97.4% in 2019; the PCR-positive rate of M. pneumoniae for adults in Beijing was 17.9% and the MRMP was 10.48%. Among the children diagnosed with community-acquired pneumonia (CAP), the PCR-positive and macrolide-resistant rates of M. pneumoniae were both higher in the severe ones. A2063G in domain V of 23S rRNA was the major macrolide-resistant mutation, accounting for more than 90%. The MIC values of all MRMP to erythromycin and azithromycin were ≥ 64 µg/ml, and the MICs of tetracycline and levofloxacin were ≤ 0.5 µg/ml and ≤ 1 µg/ml, respectively. The macrolide resistance varied in different regions and years. Among inpatients, the macrolide-resistant rate was higher in severe pneumonia. A2063G was the common mutation, and we found no resistance to tetracycline and levofloxacin.

[Metagenomic next-generation sequencing-based retrospective investigation of the drug resistance sites of Mycoplasma pneumoniae in children].

Objective: To analyze the drug-resistant gene loci of Mycoplasma pneumoniae (MP) using metagenomic next-generation sequencing (mNGS). Methods: From November 2022 to October 2023, 697 clinical samples (including sputum, alveolar lavage fluid and blood) of 686 children with Mycoplasma pneumoniae positive detected by mNGS were retrospectively analyzed. Samples were divided into intensive care unit (ICU) group and non-ICU group, Chi-square test was used to compare groups, and Mann-Kendall trend test was used to analyze the change trend of the detection rate of drug resistance gene loci over time. Results: Of the 697 samples, 164 were from the ICU group and 533 were from the non-ICU group. The detection rate of Mycoplasma pneumoniae resistance gene was 44.3% (309/697), and all detected drug-resistant gene loci of MP were A2063G. The detection rate of Mycoplasma pneumoniae in ICU group was 50.0% (82/164), and the detection rates of Mycoplasma pneumoniae resistance gene loci in sputum, alveolus lavage fluid and blood samples were 75.0% (18/24) and 48.4% (62/128), respectively. The detection rate in sputum was higher than alveolus lavage fluid samples (χ2=5.72,P=0.017). The detection rate of Mycoplasma pneumoniae in non-ICU group was 42.6% (227/533), the detection rate of Mycoplasma pneumoniae resistance gene loci in sputum and alveolar lavage fluid was 40.0% (16/40), 44.3% (201/454), and no detection rate in blood samples (0/12). There was no significant difference in the detection rate of alveolar lavage fluid and sputum (χ2=0.27, P=0.602). From November 2022 to October 2023, the detection rate of submitted samples showed an increasing trend month by month (overall: Z=3.99, ICU inspection group: Z=2.93, non-ICU group: Z=3.01, all P<0.01). Among the bacteria commonly detected with Mycoplasma pneumoniae, Streptococcus pneumoniae accounted for the highest proportion, the detection rate was 15.5% (108/697), and Epstein-Barr virus accounted for the highest proportion of 17.6% (123/697). Conclusions: From November 2022 to October 2023, the detection rate of Mycoplasma pneumoniae drug resistance gene loci showed an increasing trend. The detection rate of drug resistance gene loci in sputum samples of ICU group was higher than alveolus lavage fluid. No new drug resistance site were detected.

Visualizing translation dynamics at atomic detail inside a bacterial cell.

Translation is the fundamental process of protein synthesis and is catalysed by the ribosome in all living cells1. Here we use advances in cryo-electron tomography and sub-tomogram analysis2,3 to visualize the structural dynamics of translation inside the bacterium Mycoplasma pneumoniae. To interpret the functional states in detail, we first obtain a high-resolution in-cell average map of all translating ribosomes and build an atomic model for the M. pneumoniae ribosome that reveals distinct extensions of ribosomal proteins. Classification then resolves 13 ribosome states that differ in their conformation and composition. These recapitulate major states that were previously resolved in vitro, and reflect intermediates during active translation. On the basis of these states, we animate translation elongation inside native cells and show how antibiotics reshape the cellular translation landscapes. During translation elongation, ribosomes often assemble in defined three-dimensional arrangements to form polysomes4. By mapping the intracellular organization of translating ribosomes, we show that their association into polysomes involves a local coordination mechanism that is mediated by the ribosomal protein L9. We propose that an extended conformation of L9 within polysomes mitigates collisions to facilitate translation fidelity. Our work thus demonstrates the feasibility of visualizing molecular processes at atomic detail inside cells.

Modulatory apoptotic effects of sinomenine on Mycoplasma pneumonia through the attenuation of inflammation via ERK/JNK/NF-κB signaling pathway.

Mycoplasma pneumoniae (MPP) induced pneumonia is a common disease of children. Sinomenine (SIN) is an isoquinoline mainly sequestered from Sinomenium acutum. It is a promising drug for treating arthritis, lung, colon, liver and gastric cancer. Hence, the present study investigated the role and mechanism of SIN treatment in MPP induced pneumonia in experimental in-vivo mice model. The BALB/c male mice were separated into four groups (n = 6 mice/group): normal, MPP, MPP + SIN (20 mg/kg bw), and SIN (20 mg/kg bw) alone. Results were expressed as mean ± SD. Data were analyzed using one way Analysis of Variance (ANOVA) with the Dunnett's post hoc test using SPSS v 18.0. P value < 0.05 was considered significant. The total protein, cell count, inflammatory cytokines, MP-IgM, Monocyte chemo attractant protein-1 (MCP-1), and MP-DNA were measured. The protein expressions of Bax/Bcl-2, ERK, JNK, NF-κB were analyzed and histopathology of lungs was examined. SIN treatment significantly (p < 0.05) reduced the total proteins, cell counts in BALF, inflammatory cytokines, MP-IgM, MCP-1, MP-DNA and reversed the histological alterations. SIN attenuated the apoptotic pathway through the modulation of Bax/Bcl-2 expression. SIN alleviated pulmonary inflammatory mediators and apoptosis in MPP-infected mice via suppression of ERK/JNK/NF-κB signaling. SIN administration diminished inflammation and lung fibrosis by inhibiting apoptosis in MPP mice. Hence, SIN is a potential natural protective remedy for MPP.

Mechanism of Infantile Feire Kechuan Oral Solution against Mycoplasma pneumoniae infection of A549 cells.

BACKGROUND: Mycoplasma pneumoniae is a leading cause of community-acquired respiratory infections. Infantile Feire Kechuan Oral Solution (IFKOS) is effective for treatment of M. pneumoniae infection. The aim of this study was to explore the potential mechanism of IFKOS against M. pneumoniae infection in basal epithelial human lung adenocarcinoma A549 cells. METHODS: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the effects of IFKOS on the viability of A549 cells infected with M. pneumoniae. Optical microscopy was used to observe cell morphology and a Muse cell analyzer was used to assess apoptosis and the cell cycle phase. Enzyme-linked immunosorbent assays were employed to assess the expression levels of interleukin (IL)-4, IL-6, IL-8, IL-17, tumor necrosis factor (TNF)-α, interferon (IFN)-α, and IFN-γ. RESULTS: Under certain conditions, M. pneumoniae infection reduced the viability and inhibited the proliferation of A549 cells, promoted early apoptosis, and arrested cells in the G0/G1 phase, thus shortening the S and G2/M phases (all p < 0.05). M. pneumoniae also upregulated expression of IL-8 and TNF-α and downregulated that of IL-6 (p < 0.05), which switched the immune balance of Th1/Th2 to Th1 cells. IFKOS (5.531 mg/mL) improved the viability and proliferation of M. pneumoniae-infected A549 cells, mitigated early apoptosis, and reversed cell cycle arrest in the G0/G1 phase, thereby extending the S and G2/M phases (all, p < 0.05). IFKOS downregulated expression of IL-8 and TNF-α and upregulated that of IL-6 (p < 0.01), thereby reversing the immune imbalance of Th1/Th2. Secretion of IL-4, IL-17, IFN-α, and IFN-γ was not observed. CONCLUSION: IFKOS played a protective role in the regulation of cell viability, apoptosis, the cell cycle, and Th1/Th2 immune imbalance induced by M. pneumoniae infection and conveyed an anti-inflammatory effect in A549 cells.

A retrospective study of azithromycin and ceftizoxime for the management of children with Mycoplasma pneumoniae pneumonia.

ABSTRACT: The aim of this study was to compare the clinical efficacy of azithromycin and ceftizoxime (AC) and erythromycin and amoxicillin/sulbactam (EAS) in the treatment of children with Mycoplasma pneumoniae pneumonia (MPP).In this retrospective study, a total of 92 eligible children with MPP were included, and they were divided into a treatment group (n = 46) and a control group (n = 46). All patients were treated with intravenous ambroxol, and nebulized inhalation of budesonide and terbutaline. In addition, patients in the treatment group received AC. Patients in the control group underwent EAS. All patients in both groups were treated for a total of 10 days. Outcomes consist of erythrocyte sedimentation rate, C-reactive protein, serum lactate dehydrogenase, and interleukin 6, fever clearance time, time of cough disappearance, time of rale disappearance, time of signs disappeared by X-ray, and adverse events. All outcomes were measured after 10-day treatment.After treatment, patients who received AC exerted better improvements in erythrocyte sedimentation rate (P < .01), C-reactive protein (P < .01), serum lactate dehydrogenase (P < .01), interleukin 6 (P < .01), fever clearance time (P < .01), time of cough disappearance (P < .01), time of rale disappearance (P < .01), and time of signs disappeared by X-ray (P < .01), than those in patients who received EAS. In addition, there were not significant differences in adverse events between 2 groups.The results of this study showed that AC may benefit more than EAS for the children with MPP.

A 3D-Printed Microfluidic Device for qPCR Detection of Macrolide-Resistant Mutations of Mycoplasma pneumoniae.

Mycoplasma pneumonia (MP) is a common respiratory infection generally treated with macrolides, but resistance mutations against macrolides are often detected in mycoplasma pneumoniae in China. Rapid and accurate identification of mycoplasma pneumoniae and its mutant type is necessary for precise medication. This paper presents a 3D-printed microfluidic device to achieve this. By 3D printing, the stereoscopic structures such as microvalves, reservoirs, drainage tubes, and connectors were fabricated in one step. The device integrated commercial polymerase chain reaction (PCR) tubes as PCR chambers. The detection was a sample-to-answer procedure. First, the sample, a PCR mix, and mineral oil were respectively added to the reservoirs on the device. Next, the device automatically mixed the sample with the PCR mix and evenly dispensed the mixed solution and mineral oil into the PCR chambers, which were preloaded with the specified primers and probes. Subsequently, quantitative real-time PCR (qPCR) was carried out with the homemade instrument. Within 80 min, mycoplasma pneumoniae and its mutation type in the clinical samples were determined, which was verified by DNA sequencing. The easy-to-make and easy-to-use device provides a rapid and integrated detection approach for pathogens and antibiotic resistance mutations, which is urgently needed on the infection scene and in hospital emergency departments.

Point-of-care molecular diagnosis of Mycoplasma pneumoniae including macrolide sensitivity using quenching probe polymerase chain reaction.

OBJECTIVES: Macrolides are generally considered to be the drugs of choice for treatment of patients with Mycoplasma pneumoniae infection. However, macrolide-resistant M. pneumoniae has been emerging since about 2000. The Smart Gene® system (MIZUHO MEDY Co., Ltd., Tosu, Japan) is a novel fully automated system for detection of pathogens using the method of quantitative polymerase chain reaction (qPCR) with QProbe (QProbe PCR). The entire procedure is completed within 50 min and the size of the instrument is small (15 x 34 x 30 cm). The purpose of this study was to evaluate the usefulness of the Smart Gene® system for detection of M. pneumoniae and detection of a point mutation at domain V of the 23S rRNA gene of M. pneumoniae. MATERIALS: Pharyngeal swab samples were collected from 154 patients who were suspected of having respiratory tract infections associated with M. pneumoniae. RESULTS: Compared with the results of qPCR, the sensitivity and specificity of the Smart Gene® system were 98.7% (78/79) and 100.0% (75/75), respectively. A point mutation at domain V of the 23S rRNA gene was detected from 7 (9.0%) of 78 M. pneumoniae-positive samples by the Smart Gene® system and these results were confirmed by direct sequencing. The minimum inhibitory concentrations of clarithromycin among the 5 isolates of M. pneumoniae with a point mutation at domain V of the 23S rRNA gene were >64 µg/ml and those among the 33 isolates without a mutation in the 23S rRNA gene were <0.0625 µg/ml. CONCLUSION: The Smart Gene® system is a rapid and accurate assay for detection of the existence of M. pneumoniae and a point mutation at domain V of the 23S rRNA gene of M. pneumoniae at the same time. The Smart Gene® system is suitable for point-of-care testing in both hospital and outpatient settings.

Shuanghuanglian oral preparations combined with azithromycin for treatment of Mycoplasma pneumoniae pneumonia in Asian children: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Mycoplasma pneumoniae is one of the main causes of community-acquired pneumonia. Due to the imperfect immune system of children, this also causes Mycoplasma pneumoniae pneumonia (MPP) to be more common in children. Globally, the incidence of MPP in children is gradually increasing. This study was the first to systematically review the clinical efficacy and safety of Shuanghuanglian (SHL) oral preparations combined with azithromycin in the treatment of MPP in children. METHODS: This study fully retrieved 3 Chinese databases and 5 English databases to search the randomized controlled trials (RCTs) of SHL oral preparations combined with azithromycin in the treatment of children with MPP. The search time is from the inception to September 2020. Data extraction and risk bias evaluation were performed independently by two researchers. We conducted a Meta-analysis of all the outcome indicators. Besides, Meta-regression, subgroup analysis, and heterogeneity analysis were used for the primary outcomes to find the possible potential confounding factors. RESULTS: Finally, we included 27 RCTs involving 2884 patients. SHL oral preparations combined with azithromycin were better than azithromycin alone in response rate (RR = 1.14, 95% CI[1.11, 1.18]; low certainty evidence), disappearance time of fever(MD = -1.72, 95% CI[-2.47, -0.97]; low certainty evidence), disappearance time of cough (MD = -2.95, 95% CI[-3.55, -2.34]; low certainty evidence), and disappearance time of pulmonary rales (MD = -2.13, 95% CI[-2.88, -1.38]; low certainty evidence). The Meta-regression results showed that the course of disease, age, and method of administration may be the source of heterogeneity. Subgroup analysis and sensitivity analysis have found that the results were stable. For other related clinical symptoms, T lymphocytes, and Serum inflammatory factors, SHL oral preparations combined with azithromycin was better than azithromycin alone, and the difference was statistically significant. For adverse events with low certainty evidence, safety needs further verification. CONCLUSION: Based on the results of meta-analysis with low certainty evidence, we believed that SHL oral preparations combined with azithromycin likely be effectively improved clinical symptoms compared with azithromycin alone. Low certainty evidence showed that SHL may safety with no serious adverse events. Due to these limitations, the safety needs further verification. More high-quality, multicenter, and large-sample RCTs should be tested and verified in the future.

P1 gene of Mycoplasma pneumoniae isolated from 2016 to 2019 and relationship between genotyping and macrolide resistance in Hokkaido, Japan.

We characterized 515 Mycoplasma pneumoniae specimens in Hokkaido. In 2013 and 2014, the p1 gene type 1 strain, mostly macrolide-resistant, was dominant and the prevalence of macrolide resistance was over 50 %. After 2017, the p1 gene type 2 lineage, mostly macrolide-sensitive, increased and the prevalence of macrolide resistance became 31.0 % in 2017, 5.3 % in 2018 and 16.3 % in 2019.

Baicalin relieves Mycoplasma pneumoniae infection­induced lung injury through regulating microRNA­221 to inhibit the TLR4/NF­κB signaling pathway.

Mycoplasma pneumoniae (MP) is a common pathogen that can cause respiratory infections. MP pneumonia (MPP) leads to numerous complications, including lung injury and even death. The present study aimed to investigate the protective effects of Baicalin treatment on MP infection­induced lung injury and the molecular mechanism underlying these effects. Briefly, after mice were infected intranasally by MP and treated with Baicalin (80 mg/kg), serum levels of MP­immunoglobulin M (IgM) were detected by ELISA. The expression levels of C­reactive protein (CRP) in lung tissue were detected by immunohistochemistry and the bronchoalveolar lavage fluid (BALF) was examined by ELISA. Inflammatory factors and inflammatory cells in the BALF were assessed. The expression levels of microRNA (miR)­221 in lung tissue were examined by reverse transcription­quantitative PCR and pathological changes in lung tissue were detected by H&E staining. Cell apoptosis was evaluated by TUNEL assay and the protein expression levels of TLR4, MyD88 and NF­κB were detected by western blotting. Baicalin treatment significantly reduced serum levels of MP­IgM and CRP expression in lung tissue during MP infection. In addition, Baicalin decreased the levels of IL­1ß, IL­6, IL­18 and TNF­α in the BALF, and the number of inflammatory cells. Baicalin also reduced the inflammatory infiltration in lung tissue induced by MP infection, improved the pathological changes detected in lung tissue, reduced apoptosis, and downregulated the protein expression levels of TLR4, MyD88 and NF­κB. Furthermore, Baicalin treatment downregulated the expression of miR­221 and the protective effects of Baicalin were attenuated by miR­221 overexpression. In conclusion, Baicalin has a therapeutic effect on mice with MP infection­induced lung injury, which may be related to inhibition of miR­221 expression and regulation of the TLR4/NF­κB signaling pathway.

Predicting Mycoplasma pneumoniae and Chlamydophila pneumoniae in community-acquired pneumonia (CAP) pneumonia: epidemiological study of respiratory tract infection using multiplex PCR assays.

Community-acquired pneumonia (CAP) is a common illness that can lead to mortality. ß-lactams are ineffective against atypical pathogen including Mycoplasma pneumoniae. We used molecular examinations to develop a decision tree to predict atypical pathogens with CAP and to examine the prevalence of macrolide resistance in Mycoplasma pneumoniae. We conducted a prospective observational study of patients aged ≥ 18 years who had fever and respiratory symptoms and were diagnosed with CAP in one of two community hospitals between December 2016 and October 2018. We assessed combinations of clinical variables that best predicted atypical pathogens with CAP by classification and regression tree (CART) analysis. Pneumonia was defined as respiratory symptoms and new infiltration recognized on chest X-ray or chest computed tomography. We analyzed 47 patients (21 females, 44.7%, mean age: 47.6 years). Atypical pathogens were detected in 15 patients (31.9%; 12 Mycoplasma pneumoniae, 3 Chlamydophila pneumoniae). Ten patients carried macrolide resistant Mycoplasma pneumoniae (macrolide resistant rate 83.3%). CART analysis suggested that factors associated with presence of atypical pathogens were absence of crackles, age < 45 years, and LD ≥ 183 U/L (sensitivity 86.7% [59.5, 98.3], specificity 96.9% [83.8, 99.9]). ur simple clinical decision rules can be used to identify primary care patients with CAP that are at risk for atypical pathogens. Further research is needed to validate its usefulness in various populations.Trial registration Clinical Trial (UMIN trial ID: UMIN000035346).

The combination of initial markers to predict refractory Mycoplasma pneumoniae pneumonia in Chinese children: a case control study.

OBJECTIVE: Thise study is aimed to identify the biomarkers for predicting refractory Mycoplasma pneumoniae pneumonia in Chinese children at the time of the hospital admission. METHODS: The case control study retrospectively analyzed the clinical characteristics and laboratory results of Chinese pediatric patients presenting with common and refractory Mycoplasma pneumoniae pneumonia (CMPP and RMPP). Overall, there were 216 cases in the CMPP group and 88 cases in the RMPP group. Venous blood was collected, and serum ferritin (SF), lactate dehydrogenase (LDH), D-dimer, C-reactive protein (CRP), procalcitonin (PCT), neutrophil count/lymphocyte count (NLR), and other indexes were measured. A single factor analysis, an ROC curve analysis, and a logistic regression analysis were used to determine the independent risk factors of RMPP and find combination of initial markers for RMPP. RESULTS: There were significant differences between the RMPP group and the CMPP group in mean SF (529.82 [357.86] vs. 147.22 [122.68] ng/mL), LDH (522.08 [389.08] vs. 286.85 [101.02] U/L), D-dimer (6.65 [5.66] vs. 1.46 [2.45] µg/mL), CRP (62.80 [52.15] vs. 19.03 [24.50] mg/L), PCT (0.80 [2.61] vs. 0.16 [0.44]) ng/mL, and NLR (4.14 [2.52] vs. 2.62 [1.55]), with P < 0.05 for each comparison. ROC cut-off values of the above indexes were 329.01 ng/mL, 375.50 U/L, 2.10 µg/mL, 43.08 mg/L, 0.08 ng/mL, and 2.96, respectively. The logistic regression analysis showed that SF, D-dimer, and CRP are independent risk factors to predict RMPP. CONCLUSION: SF, D-dimer, and CRP are statistically significant biomarkers to predict RMPP in Chinese children patients in the settings of pediatric emergency department.

[Current microbiological aspects of community respiratory infection beyond COVID-19]. / Aspectos microbiológicos actuales de la infección respiratoria comunitaria más allá de la COVID-19.

From a microbiological point of view, both empirical and targeted antimicrobial treatment in respiratory infection is based on the sensitivity profile of isolated microorganisms and the possible resistance mechanisms that they may present. The latter may vary in different geographic areas according to prescription profiles and vaccination programs. Beta-lactam antibiotics, fluoroquinolones, and macrolides are the most commonly used antimicrobials during the exacerbations of chronic obstructive pulmonary disease and community-acquired pneumonia. In their prescription, different aspects such as intrinsic activity, bactericidal effect or their ability to prevent the development of resistance must be taken into account. The latter is related to the PK/PD parameters, the mutant prevention concentration and the so-called selection window. More recently, the potential ecological impact has grown in importance, not only on the intestinal microbiota, but also on the respiratory one. Maintaining the state of eubiosis requires the use of antimicrobials with a low profile of action on anaerobic bacteria. With their use, the resilience of the bacterial populations belonging to the microbiota, the state of resistance of colonization and the collateral damage related to the emergence of resistance to the antimicrobials in pathogens causing the infections and in the bacterial populations integrating the microbiota.

Severe Pediatric Mycoplasma pneumoniae Infection Requiring Veno-venous Extracorporeal Membrane Oxygenation.

ABSTRACT: Mycoplasma pneumoniae (MP) is an atypical bacterial pathogen that typically causes mild respiratory symptoms. Rarely, MP is associated with acute respiratory distress syndrome, a condition marked by widespread inflammation in the lungs that often requires invasive support. We report a case of severe acute respiratory distress syndrome requiring veno-venous extracorporeal membrane oxygenation in an otherwise healthy adolescent because of MP.

Effect of Qingfei Huatan Huoxue Decoction combined with azithromycin on pulmonary function and inflammatory factors in children with Mycoplasma pneumonia.

To investigate the effect of Qingfei Huatan Huoxue Decoction combined with azithromycin on pulmonary function and inflammatory factors in children with Mycoplasma pneumonia. A total of 155 children with Mycoplasma pneumonia of toxic heat blocking lung syndrome were randomly divided into the control group (n=77) and the observation group (n=78) from March 2020 to March 2021. Both groups of children were given conventional treatment and azithromycin intravenous drip and the observation group was additionally given oral administration of Qingfei Huatan Huoxue Decoction, with 7 days as a course of treatment totaling 2 courses. The lung function, inflammatory factor level, immune function and coagulation function were compared between the two groups before and after treatment. After treatment, the symptom integral of fever, cough and pulmonary wet rales in the two groups were reduced, while FEV1, PEF and FEV1/ FVC were significantly increased, serum TNF-α, IFN- γ and IL-6 were significantly reduced, the levels of Immunoglobulin M (IgM), IgG and IgA were significantly reduced and plasma PT and APTT were significantly reduced, with more significant changes observed in the observation group (all P<0.05). The disappearance time of fever, cough and pulmonary moist rales in the observation group was significantly shorter than that in the control group (P<0.05). The recovery rate of the observation group was significantly higher than that of the control group (P<0.05). Qingfei Huatan Huoxue Decoction combined.

Rational stepwise approach for Mycoplasma pneumoniae pneumonia in children.

Mycoplasma pneumoniae is a common pathogen that causes community-acquired pneumonia. In the past, M. pneumoniae was sensitive to macrolide antibiotics, and M. pneumoniae pneumonia (MPP) was usually a benign and self-limiting disease. However, despite use of the appropriate antibiotics, persistent fever and clinical deterioration may occur, leading to severe disease. Two major complicated conditions that may be clinically encountered are macrolide-resistant MPP and refractory MPP. Regarding the epidemics in Taiwan, before 2017, the mean rate of macrolide resistance was below 30%. Notably, since 2018, the prevalence of macrolide-resistant MPP in Taiwan has increased rapidly. Macrolide-resistant MPP shows persistent fever and/or no radiological regression to macrolide antibiotics and may even progress to severe and complicated pneumonia. Tetracyclines (doxycycline or minocycline) or fluoroquinolones are alternative treatments for macrolide-resistant MPP. Refractory MPP is characterized by an excessive immune response against the pathogen. In this context, corticosteroids have been suggested as an immunomodulator for downregulating the overactive host immune reaction. Overuse of macrolides may contribute to macrolide resistance, and thereafter, an increase in macrolide-resistant MPP. Delayed effective antimicrobial treatment is associated with prolonged and/or more severe disease. Thus, the appropriate prescription of antibiotics, as well as the rapid and accurate diagnosis of MPP, is important. The exact starting point, dose, and duration of the immunomodulator are yet to be established. We discuss these important issues in this review.

Modelling persistent Mycoplasma pneumoniae biofilm infections in a submerged BEAS-2B bronchial epithelial tissue culture model.

Introduction. Infections with the respiratory pathogen Mycoplasma pneumoniae are often chronic, recurrent and resistant, persisting after antibiotic treatment. M. pneumoniae grown on glass forms protective biofilms, consistent with a role for biofilms in persistence. These biofilms consist of towers of bacteria interspersed with individual adherent cells.Hypothesis/Gap Statement. A tissue culture model for M. pneumoniae biofilms has not been described or evaluated to address whether growth, development and resistance properties are consistent with persistence in the host. Moreover, it is unclear whether the M. pneumoniae cells in the biofilm towers and individual bacterial cells have distinct roles in disease.Aim. We evaluated the properties of biofilms of M. pneumoniae grown on the immortalized human bronchial epithelial cell line BEAS-2B in relation to persistence in the host. We observed nucleation of biofilm towers and the disposition of individual cells in culture, leading to a model of how tower and individual cells contribute to infection and disease.Methodology. With submerged BEAS-2B cells as a substrate, we evaluated growth and development of M. pneumoniae biofilms using scanning electron microscopy and confocal laser scanning microscopy. We characterized resistance to erythromycin and complement using minimum inhibitory concentration assays and quantification of colony forming units. We monitored biofilm tower formation using time-lapse microscopic analysis of host-cell-free M. pneumoniae cultures.Results. Bacteria grown on host cells underwent similar development to those grown without host cells, including tower formation, rounding and incidence of individual cells outside towers. Erythromycin and complement significantly reduced growth of M. pneumoniae. Towers formed exclusively from pre-existing aggregates of bacteria. We discuss a model of the M. pneumoniae biofilm life cycle in which protective towers derive from pre-existing aggregates, and generate individual cytotoxic cells.Conclusion . M. pneumoniae can form protective biofilms in a tissue culture model, implicating biofilms in chronic infections, with aggregates of M. pneumoniae cells being important for establishing infections.

Clonal spread of macrolide-resistant Mycoplasma pneumoniae sequence type-3 and type-17 with recombination on non-P1 adhesin among children in Taiwan.

OBJECTIVES: Mycoplasma pneumoniae is currently the most commonly detected bacterial cause of childhood community-acquired pneumonia in several countries. Of note, clonal expansion of macrolide-resistant ST3 occurred in Japan and South Korea. An alarming surge in macrolide resistance complicates the treatment of pneumonia. We aimed to evaluate the clinical manifestation and clonal relatedness of M. pneumoniae circulating among children in Taiwan. METHODS: We prospectively enrolled 626 children with radiologically confirmed pneumonia between 2017 and 2019. An M. pneumoniae infection was suspected on clinical grounds, and tested by real-time PCR and oropharyngeal swab cultures. We used multilocus sequence typing and whole-genome sequencing to characterize the genetic features of M. pneumoniae. RESULTS: A total of 226 children with M. pneumoniae pneumonia were enrolled. Macrolide resistance was found in 77% (174/226) of patients. Multi-locus sequence typing revealed that ST3 (n = 93) and its single-locus variant ST17 (n = 84) were the predominant clones among macrolide-resistant strains. ST17 presented clinical characteristics comparable to its ancestor ST3. On multivariate analysis, macrolide resistance (OR 3.5; 95% CI 1.4-8.5; p 0.007) was independently associated with fever >72 hours after macrolide treatment. By whole-genome sequencing, prediction analysis of recombination sites revealed one recombination site in ST3 and ST17 compared with M29 (a macrolide-sensitive ST3 strain isolated from China in 2005) containing cytadhesin MgpC-like protein, RepMP4 and RepMP5. ST17 had another recombination site containing an adhesin and RepMP2/3. CONCLUSIONS: In addition to macrolide resistance, ST3 and its ST17 variant might evolve through recombination between repetitive sequences and non-P1 cytadhesins for persistent circulation in Taiwan.

Outbreak of Mycoplasma pneumoniae at a military academy.

In 2019, an outbreak of Mycoplasma pneumoniae occurred at a military academy in China. The attack rate (10.08%,60/595) was significantly different among the units. High-intensity training and crowded environments to which cadets are exposed are the high risk factors for the outbreak of M. pneumoniae. In-time prevention and control measures effectively controlled the spread of the epidemic.