Comparison of Efficacy of Antimicrobial Agents Among Hospitalized Patients With Mycoplasma pneumoniae Pneumonia in Japan During Large Epidemics of Macrolide-Resistant M. pneumoniae Infections: A Nationwide Observational Study

Treatment modalities for fever duration in children with Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae is the leading cause of community-acquired pneumonia in children. With increasing macrolide resistance, the use of second-line antibiotics such as tetracyclines and quinolones is also increasing. Clinical data were collected from 13 institutions between September 2023 and February 2024. MPP was defined as the detection of M. pneumoniae via polymerase chain reaction or serological tests and radiologic evidence of pneumonic infiltration. Among the 389 children with MPP included in the analysis, 89.1% were macrolide resistant (MR). The treatment groups were as follows: spontaneous resolution (SR, 21.9%), macrolide alone (ML, 18.0%), macrolide with other treatments (ML-O, 38.0%), and second-line antibiotics and/or steroids (2nd-A/S, 22.1%). The median fever duration was 5 days for the SR group, 7 days for both the ML and 2nd-A/S groups, and 8 days for the ML-O group. The ML-O group had significantly greater hospitalization rates (93.9% vs. 81.4-84.7%, P = 0.023) and longer hospital stays (5.0 days vs. 3.0-4.0 days, P < 0.001). The median times to defervescence from the initiation of macrolide and second-line treatments were 2-3 days and 0-2 days, respectively. In conclusion, despite high MR rates, macrolide monotherapy remains effective in many patients, even those with macrolide-resistant M. pneumoniae.

Outbreak of Mycoplasma pneumoniae pneumonia in hospitalized patients: Who is concerned? Nord Franche-Comté Hospital, France, 2023-2024

We report an outbreak of confirmed Mycoplasma pneumoniae community-acquired pneumonia (CAP) in Nord Franche-Comté Hospital, France, from 14 November 2023 to 31 January 2024. All 13 inpatients (11 adults with a mean age of 45.5 years and 2 children) were diagnosed with positive serology and/or positive reverse transcription polymerase chain reaction (RT-PCR) on respiratory specimens. All patients were immunocompetent and required oxygen support with a mean duration of oxygen support of 6.2 days. Two patients were transferred to the intensive care unit (ICU) but were not mechanically ventilated. Patients were treated with macrolides (n = 12, 92.3%) with recovery in all cases. No significant epidemiological link was reported in these patients.

Atypical Pathogens in Adult Community-Acquired Pneumonia and Implications for Empiric Antibiotic Treatment: A Narrative Review

Atypical pathogens are intracellular bacteria causing community-acquired pneumonia (CAP) in a significant minority of patients. Legionella spp., Chlamydia pneumoniae and psittaci, Mycoplasma pneumoniae, and Coxiella burnetii are commonly included in this category. M. pneumoniae is present in 5-8% of CAP, being the second most frequent pathogen after Streptococcus pneumoniae. Legionella pneumophila is found in 3-5% of inpatients. Chlamydia spp. and Coxiella burnetii are present in less than 1% of patients. Legionella longbeachae is relatively frequent in New Zealand and Australia and might also be present in other parts of the world. Uncertainty remains on the prevalence of atypical pathogens, due to limitations in diagnostic means and methodological issues in epidemiological studies. Despite differences between CAP caused by typical and atypical pathogens, the clinical presentation alone does not allow accurate discrimination. Hence, antibiotics active against atypical pathogens (macrolides, tetracyclines and fluoroquinolones) should be included in the empiric antibiotic treatment of all patients with severe CAP. For patients with milder disease, evidence is lacking and recommendations differ between guidelines. Use of clinical prediction rules to identify patients most likely to be infected with atypical pathogens, and strategies of narrowing the antibiotic spectrum according to initial microbiologic investigations, should be the focus of future investigations.

Mycoplasma pneumoniae pneumonia with pulmonary embolism: A study on pediatric cases in Jilin province of China

Mycoplasma is one of the most common pathogens causing community-acquired pneumonia in pediatric patients. In recent years, the number of refractory or severe cases with drug resistance has been gradually increasing and cases that developed embolism after Mycoplasma pneumoniae (M. pneumoniae) infection have been reported. The present study retrospectively analyzed the clinical features, diagnosis and treatment of M. pneumoniae pneumonia (MPP) combined with pulmonary embolism (PE) in a series of 7 cases encountered between January 1st, 2016 to August 1st, 2019 at the Department of Pediatric Intensive Care Unit of The First Hospital of Jilin University (Changchun, China). Combined with relevant Chinese and international studies published during the last two decades, a comprehensive analysis was performed. All of the pediatric patients of the present study had fever, cough and dyspnea respiratory symptoms at onset and the disease progressed rapidly. Thereafter, PE was confirmed by a series of examinations. Pulmonary CT indicated patchy inflammations and significantly elevated D-dimer levels, accompanied by positive anticardiolipin antibodies. Furthermore, a filling defect in the pulmonary artery branch was observed on CT pulmonary angiography (CTPA) examination. In 2 cases, the condition was improved with anti-infection and anticoagulation treatment with low-molecular-weight heparin and warfarin, respectively, and the pulmonary embolism disappeared after 3-4 months. A total of 5 cases, who were not responsive to the drug treatment, underwent surgical resection. During the operation, the local tissues were determined to be infarcted and the pathological diagnosis was consistent with pulmonary infarction. Among the 5 cases, 2 died of Acute Respiratory Distress Syndrome at 3-8 days after the operation. The remaining patients underwent 6-12 months of follow-up and respiratory rehabilitation and their quality of life is now good. In conclusion, compared with healthy individuals, pediatric patients with critical MPP have an elevated risk of embolism. It is necessary to be vigilant regarding whether MMP is combined with PE and perform timely CTPA examination. Early detection, early treatment and surgical intervention (if necessary) may significantly reduce the risk of mortality and disability.

Macrolide-resistant Mycoplasma pneumoniae pneumonia in transplantation: Increasingly typical?

Mycoplasma pneumoniae is one of the most common bacterial causes of pneumonia. Macrolide-resistant M pneumoniae (MRMP) was documented in 7.5% of isolates in the United States. Resistance portends poor outcomes to macrolide therapy, yet patients respond well to fluoroquinolones or tetracyclines such as minocycline. However, MRMP may be under-appreciated because M pneumoniae generally causes relatively mild infections in non-immunosuppressed adults that may resolve without effective therapy and because microbiological confirmation and susceptibility are not routinely performed. We report two cases of pneumonia due to MRMP in kidney transplant recipients. Both patients required hospital admission, worsened on macrolide therapy, and rapidly defervesced on doxycycline or levofloxacin. In one case, M pneumoniae was only identified by multiplex respiratory pathogen panel analysis of BAL fluid. Macrolide resistance was confirmed in both cases by real-time PCR and point mutations associated with macrolide resistance were identified. M pneumoniae was isolated from both cases, and molecular genotyping revealed the same genotype. In conclusion, clinicians should be aware of the potential for macrolide resistance in M pneumoniae, and may consider non-macrolide-based therapy for confirmed or non-responding infections in patients who are immunocompromised or hospitalized.

Relieving Sore Throat Formula Exerts a Therapeutic Effect on Pharyngitis through Immunoregulation and NF-κB Pathway

Relieving Sore Throat Formula (RSTF) is a formula approved by the China Food and Drug Administration and has been used for the treatment of pharyngitis in clinic for many years. However, the potential pharmacological mechanism still remains unknown. We combined multiple methods including bioinformatics data digging, network pharmacology analysis, and pathway analysis to predict the potential target of RSTF. We verified our in silico prediction results with an in vivo/vitro antibacterial effect test, mouse phagocytic index test, proliferation, transformation, and migration of mouse spleen lymphocytes. Alteration of NF-κB pathway was determined by Western blotting, immunofluorescence, and PCR. The in vivo experiments demonstrated that the RSTF could significantly relieve the symptoms of pharyngitis. A rat saliva secretion test showed that RSTF can effectively relieve the xerostomia symptom. A phenol red excretion test showed that RSTF has an eliminating phlegm effect. A hot plate method and granuloma experiment proved that RSTF also have analgesic and anti-inflammatory effects. In silico prediction demonstrates that 70 active compounds of RSTF were filtered out through ADME screening and 84 putative targets correlated with different diseases. Pathway enrichment analysis showed that the candidate targets were mostly related to the response to bacteria and immunity signalling pathways, which are known contributors to pharyngitis. Experimental results confirmed that RSTF exerted therapeutic effects on pharyngitis mainly by antibacterial effect and downregulation of NF-κB activities. It is demonstrated both in silico and in vivo/vitro that RSTF exerted therapeutic effects on pharyngitis mainly through an antibiotic effect and downregulation of NF-κB signalling pathway.

Clinical Role of Serum Interleukin-17A in the Prediction of Refractory Mycoplasma pneumoniae Pneumonia in Children

Background

Mycoplasma pneumoniae pneumonia (MPP) is a common community-acquired pneumonia (CAP) in children, which may become refractory MPP (RMPP) to treatment.

Objective

The purpose of this study was to evaluate the clinical utility of measuring serum interleukin (IL)-17A to predict RMPP.

Patients and Methods

A retrospective clinical study at a single pediatric center included a review of the medical records of all children hospitalized for CAP between November 2015 and October 2019. The diagnosis of MPP was based on clinical presentation, chest radiography, and measurement of serum anti-Mycoplasma immunoglobulin IgM antibody titer using the microparticle agglutination method or sputum samples for Mycoplasma pneumoniae by PCR. Serum levels of IL-18 and IL-17A were determined by ELISA.

Results

Of the 625 children diagnosed with CAP, there were 154 children with MPP and without underlying diseases who were divided into a non-refractory MPP (NRMPP) group (n = 109) and a RMPP group (n = 45). The RMPP group had a higher incidence of tachypnea, cyanosis, hypoxia, segmental or lobar pneumonia, pleural effusion, and a longer period of hospitalization compared with NRMPP group (all P-values < 0.05). A serum IL-17A level above 10.8 pg/mL was a predictor for RMPP: area under the curve (AUC) 0.822; standard error (SE) 0.039; 95% confidence interval (CI) 0.746–0.897; diagnostic sensitivity and specificity of 77.8% and 77.1%, respectively. An LDH level above 436.5 IU/L and an IL-18 level above 464.5 pg/mL were the second most useful markers for RMPP: AUC 0.775, 0.775; SE 0.038, 0.039; 95% CI 0.700–0.850, 0.698–0.852; sensitivity 77.8%, 82.2%; specificity 62.4%, 59.6%; respectively.

Conclusion

This preliminary study of MPP in a pediatric population has shown that measurement of serum IL-17A may be a useful marker for the predictor of RMPP.