Molecular characterization of genomic DNA in mycoplasma pneumoniae strains isolated from serious mycoplasma pneumonia cases in 2016, Yunnan, China

Molecular features and antimicrobial susceptibility of Mycoplasma pneumoniae isolates from pediatric inpatients in Weihai, China

OBJECTIVES

We analyzed the molecular features and antimicrobial susceptibility of Mycoplasma pneumoniae isolates from Weihai in 2019.

METHODS

Pharyngeal swabs of 160 pediatric patients with pneumonia-related symptoms were collected and subjected to culture and subsequent characteristic analysis. The characteristics of M. pneumoniae isolates were analyzed through real-time PCR and genotyping. Antimicrobial susceptibility test was performed against 4 antibiotics. All isolates were amplified for the analysis of macrolide (ML) resistant gene of the 23S rRNA and were genotyped with multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) and 'AGT' VNTR detection in p1 gene.

RESULTS

M. pneumoniae nucleic acid and culture positive rate of 160 specimens were 87.6% and 51.3%, respectively. Almost all isolates were ML resistant (81/82). Point mutation at 2063 site in 23S rRNA was identified in all ML resistant isolates. ML resistance rate of genotype 2 isolates was 97.6% in the M. pneumoniae isolates in Weihai. MLVA types 4/5/7/2 and 4/5/7/3 belonged to genotype 1, while 3/5/6/2 belonged to genotype 2. Numbers of 'AGT' VNTR in p1 gene from all isolates was in a range of 5-15.

CONCLUSIONS

This is the first report that the two genotypes of M. pneumoniae isolates were presented in relative equivalent ratio, with genotype 2 slightly dominant, in pediatric patients in Weihai in 2019, and the overall ML resistance rate was close to 100%. Minimum inhibitory concentration (MIC) of erythromycin in A2063T ML resistance in M. pneumoniae in Weihai was higher than previous publications.

Clinical efficacy enhancement of a Chinese herbal injection in the treatment of mycoplasma pneumonia in children: A protocol of randomized controlled trial

BACKGROUND

Mycoplasma pneumonia is a common disease in pediatrics, and macrolides is the first choice for the treatment. However, the increase of antibiotic resistance of macrolides makes it more and more complicated for clinical treatment. Due to the long term treatment of macrolides, it may increase the incidence of nausea, vomiting, abdominal pain, diarrhea, and other gastrointestinal symptoms, vascular phlebitis, liver and kidney function damage. Tanreqing injection, a Chinese herbal extraction injection, has advantages in the treatment of mycoplasma pneumonia in children, and it could improve the curative effect, shortening the course of disease, and reducing the side effects. Yet there is a lack of standard clinical studies to verify it, so this randomized controlled trial (RCT) will evaluate the efficacy and safety of Tanreqing injection combined with azithromycin in the treatment of mycoplasma pneumonia in children.

METHODS

This is a prospective RCT to study the efficacy and safety of Tanreqing injection combined with azithromycin in the treatment of mycoplasma pneumonia in children. It is approved by the Clinical Research Society of our hospital. According to the 1:1 ratio, the patients will be randomly divided into Tanreqing injection combined with azithromycin group (observation group) and azithromycin group (control group). Duration of hospitalization, clinical improvement 7 days after admission, changing laboratory tests, pulmonary function, immunoglobulin level, and adverse reactions will be compared between the 2 groups. The data will be analyzed by SPSS 16.0 software.

DISCUSSION

This study will evaluate the efficacy and safety of Tanreqing injection combined with azithromycin in the treatment of mycoplasma pneumonia in children. The results of this experiment will provide clinical basis for the treatment of mycoplasma pneumonia in children with Tanreqing injection combined with azithromycin.

TRIAL REGISTRATION

OSF Registration number: DOI 10.17605/OSF.IO/X6VFS.

Mycoplasma pneumoniae Infections: Pathogenesis and Vaccine Development

Mycoplasma pneumoniae is a major causative agent of community-acquired pneumonia which can lead to both acute upper and lower respiratory tract inflammation, and extrapulmonary syndromes. Refractory pneumonia caused by M. pneumonia can be life-threatening, especially in infants and the elderly. Here, based on a comprehensive review of the scientific literature related to the respective area, we summarize the virulence factors of M. pneumoniae and the major pathogenic mechanisms mediated by the pathogen: adhesion to host cells, direct cytotoxicity against host cells, inflammatory response-induced immune injury, and immune evasion. The increasing rate of macrolide-resistant strains and the harmful side effects of other sensitive antibiotics (e.g., respiratory quinolones and tetracyclines) in young children make it difficult to treat, and increase the health risk or re-infections. Hence, there is an urgent need for development of an effective vaccine to prevent M. pneumoniae infections in children. Various types of M. pneumoniae vaccines have been reported, including whole-cell vaccines (inactivated and live-attenuated vaccines), subunit vaccines (involving M. pneumoniae protein P1, protein P30, protein P116 and CARDS toxin) and DNA vaccines. This narrative review summarizes the key pathogenic mechanisms underlying M. pneumoniae infection and highlights the relevant vaccines that have been developed and their reported effectiveness.

The clinical significance of IL-6 s and IL-27 s in Bronchoalveolar lavage fluids from children with mycoplasma pneumoniae pneumonia

Background

IL-6 was associated with the severity of mycoplasma pneumoniae pneumonia (MPP). But the relationship between IL-27 and MPP was unknown.

Methods

Ninety-eight patients with MPP < 14 years old were enrolled in this study and divided into groups by severity (mild cases and severe cases), infection types (MP single infection group and MP mixed infection group) and DNA loads (low MP DNA loads group and high MP DNA loads group), respectively. Fifteen children with foreign bodies in bronchus were also enrolled as control. IL-6 s and IL-27 s in bronchoalveolar lavage fluids (BALFs) from these children were measured by ELISA.

Results

There were significant differences in IL-6 s of BALFs from patients between mild cases and severe cases, MP single infection group and MP mixed infection group, and low MP DNA loads group and high MP DNA loads group, respectively (P < 0.05). Compared with IL-6 s of BALFs from control, IL-6 s in BALFs from the 6 patient groups were significantly higher (P < 0.05). IL-27 s in BALFs from MP mixed infection group were significantly lower than those from MP single infection group and control (P < 0.05) respectively.

Conclusion

IL-6 was firmly associated with MPP and had potential application in clinical practice while IL-27 was not related to MP infection.

Assessment of levels of D-dimer and interferon-γ in pediatric patients with Mycoplasma pneumoniae pneumonia and its clinical implication

Levels of D-dimer and interferon-γ (INF-γ) in pediatric patients with Mycoplasma pneumoniae pneumonia (MPP) were assessed to explore its clinical implication in evaluating the disease severity and patients' prognosis. Enrolled in this study as subjects were 185 pediatric patients with MPP who were admitted to the Department of Pediatrics of the Second Affiliated Hospital of Qiqihar Medical University and the First Hospital of Qiqihar City from January 2017 to October 2017 and 115 healthy children who underwent physical examination during the same time period. Patients were divided into two groups according to the severity of their pneumonia: Severe pneumonia group with 95 patients and mild pneumonia group with 90 patients. A total of 92 healthy children were assigned to the control group. Immunoassay was performed to measure the serum levels of D-dimer and INF-γ. The levels of these two markers were compared. In terms of D-dimer, the levels in pediatric patients in pneumonia groups were all higher than that in the healthy children (p<0.0001). After treatment for 120 h, the D-dimer and INF-γ levels in both pneumonia groups were lower than those before treatment (p<0.001). Among the patients in both the mild and severe pneumonia groups, those who developed extra-pulmonary complications had higher levels of D-dimer and INF-γ than those who did not developed extra-pulmonary complications (p<0.001). Increased levels of D-dimer and INF-γ were observed in pediatric patients with MPP. Assessment of the levels of D-dimer and INF-γ in serum may help with the diagnosis of severe MPP in children and predicting the occurrence of complications. This study provided more theoretical basis for the early diagnosis and identification of MPP in children, and can be used as a guideline in evaluating the severity and preventing complications.