Macrolide resistance and molecular typing of Mycoplasma pneumoniae infections during a 4 year period in Spain

Expert consensus on the diagnosis and treatment of macrolide-resistant Mycoplasma pneumoniae pneumonia in children

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae) is a significant contributor to community-acquired pneumonia among children. Since 1968, when a strain of M. pneumoniae resistant to macrolide antibiotics was initially reported in Japan, macrolide-resistant M. pneumoniae (MRMP) has been documented in many countries worldwide, with varying incidence rates. MRMP infections lead to a poor response to macrolide antibiotics, frequently resulting in prolonged fever, extended antibiotic treatment, increased hospitalization, intensive care unit admissions, and a significantly higher proportion of patients receiving glucocorticoids or second-line antibiotics. Since 2000, the global incidence of MRMP has gradually increased, especially in East Asia, which has posed a serious challenge to the treatment of M. pneumoniae infections in children and attracted widespread attention from pediatricians. However, there is still no global consensus on the diagnosis and treatment of MRMP in children.

METHODS

We organized 29 Chinese experts majoring in pediatric pulmonology and epidemiology to write the world's first consensus on the diagnosis and treatment of pediatric MRMP pneumonia, based on evidence collection. The evidence searches and reviews were conducted using electronic databases, including PubMed, Embase, Web of Science, CNKI, Medline, and the Cochrane Library. We used variations in terms for "macrolide-resistant", "Mycoplasma pneumoniae", "MP", "M. pneumoniae", "pneumonia", "MRMP", "lower respiratory tract infection", "Mycoplasma pneumoniae infection", "children", and "pediatric".

RESULTS

Epidemiology, pathogenesis, clinical manifestations, early identification, laboratory examination, principles of antibiotic use, application of glucocorticoids and intravenous immunoglobulin, and precautions for bronchoscopy are highlighted. Early and rapid identification of gene mutations associated with MRMP is now available by polymerase chain reaction and fluorescent probe techniques in respiratory specimens. Although the resistance rate to macrolide remains high, it is fortunate that M. pneumoniae still maintains good in vitro sensitivity to second-line antibiotics such as tetracyclines and quinolones, making them an effective treatment option for patients with initial treatment failure caused by macrolide antibiotics.

CONCLUSIONS

This consensus, based on international and national scientific evidence, provides scientific guidance for the diagnosis and treatment of MRMP in children. Further studies on tetracycline and quinolone drugs in children are urgently needed to evaluate their effects on the growth and development. Additionally, developing an antibiotic rotation treatment strategy is necessary to reduce the prevalence of MRMP strains.

Macrolide-resistant mycoplasma pneumoniae infection in children observed during a period of high incidence in Henan, China

Objective

Mycoplasma pneumoniae (Mp) is one of the major pathogens that causes respiratory tract infections, and macrolide resistance has increased rapidly in recent years due to the inappropriate use of macrolides in northeastern Asia. In the present study, we aimed to investigate Mp infection and macrolide resistance during a period of high incidence of Mp infection in Henan, China.

Methods

A total of 29473 suspected children with Mp infection were enrolled in the study from July to December 2023. Throat swab specimens were collected from all the study subjects, and real-time PCR was performed to detect the Mp-DNA and macrolide resistance-associated A2063G or A2064G mutations.

Results

The overall percentage of Mp-DNA-positive patients was 51.1 %, and the percentage of macrolide-resistant strains was 91 %. The rate of macrolide resistance remained stable from July to December. The Mp-DNA positivity rates among the different age groups from low to high were 0-1, 1-3, 3-6, 10-18 and 6-10 years. The macrolide resistance rate was the lowest in the 0-1 age group and highest in the 6-10 age group. No difference in the rate of macrolide resistance was observed between male and female children.

Conclusions

The macrolide resistance rate of Mp did not change during the investigated period of high incidence of infection, and no sex difference existed. The macrolide resistance rate of Mp was the lowest in children under 1 year old.

Position statement of the Spanish Society of Paediatric Infectious diseases on the diagnosis and treatment of Mycoplasma pneumoniae infection

Mycoplasma pneumoniae (M. pneumoniae) is a bacterium with particular characteristics that give rise to a broad clinical spectrum, being respiratory infection the most frequent presentation. Infection by M. pneumoniae occurs in cyclical epidemics, and paediatricians in Spain have noticed an increase in cases since January 2024, establishing hospital registers to collect surveillance data (as it is not a notifiable disease in Spain). The diagnosis of infection by M. pneumoniae is made through serological testing and/or the detection of genetic material by means of polymerase chain reaction (PCR). Neither methods can differentiate between colonization and active infection, so a precise diagnosis is not possible and testing should only be requested in the case of high clinical suspicion. The role of antibiotherapy in infection by M. pneumoniae in its different clinical variants is not well defined. Most infections are self-limiting and mild, and there is insufficient evidence to support the use of antibiotherapy in these cases. Antibiotic treatment is justified in patients with risk factors for the development of severe disease (Down syndrome, anatomical or functional asplenia, immunosuppression), in hospitalized patients with respiratory infection and in patients with moderate or severe extrapulmonary forms. Taking into account aspects concerning the rational use of antimicrobials, the treatment of choice would be clarithromycin, with azithromycin as an alternative, reserving the use of doxycycline and levofloxacin for cases of antimicrobial resistance and/or infections of the central nervous system.

The clinical significance of macrolide resistance in pediatric Mycoplasma pneumoniae infection during COVID-19 pandemic

Background

Mycoplasma pneumoniae (MP) is a commonly occurring pathogen causing community-acquired pneumonia (CAP) in children. The global prevalence of macrolide-resistant MP (MRMP) infection, especially in Asian regions, is increasing rapidly. However, the prevalence of MRMP and its clinical significance during the COVID-19 pandemic is not clear.

Methods

This study enrolled children with molecularly confirmed macrolide-susceptible MP (MSMP) and MRMP CAP from Beijing Children's Hospital Baoding Hospital, Capital Medical University between August 2021 and July 2022. The clinical characteristics, laboratory findings, chest imaging presentations, and strain genotypes were compared between patients with MSMP and MRMP CAP.

Results

A total of 520 hospitalized children with MP-CAP were enrolled in the study, with a macrolide resistance rate of 92.7%. Patients with MRMP infection exhibited more severe clinical manifestations (such as dyspnea and pleural effusion) and had a longer hospital stay than the MSMP group. Furthermore, abnormal blood test results (including increased LDH and D-dimer) were more common in the MRMP group (P<0.05). Multilocus variable-number tandem-repeat analysis (MLVA) was performed on 304 samples based on four loci (Mpn13-16), and M3562 and M4572 were the major types, accounting for 74.0% and 16.8% of the strains, respectively. The macrolide resistance rate of M3562 strains was up to 95.1%.

Conclusion

The prevalence of MRMP strains in hospitalized CAP patients was extremely high in the Baoding area, and patients infected with MRMP strains exhibited more severe clinical features and increased LDH and D-dimer. M3562 was the predominant resistant clone.

The molecular characteristics, diagnosis, and treatment of macrolide-resistant Mycoplasma pneumoniae in children

The purpose of this study is to review the molecular characteristics, the diagnosis, and treatment of the widespread infection of macrolide-resistant Mycoplasma pneumoniae (M. pneumoniae; MRMP) in children, thus providing a better knowledge of this infection and presenting the associated problems. Single point mutations in the V region of the 23S rRNA gene of M. pneumoniae genome are associated with macrolide resistance. P1-1, MLVA4-5-7-2, and ST3 are usually the predominated genetic types in the M. pneumoniae epidemics. The short-term two times serological IgM (or together with IgG) test in the acute stage can be used for confirmation. Combined serological testing and PCR might be a more prudent method to reduce macrolide consumption and antibiotic selective pressure in a clinical setting. Molecular methods for the detection of single-nucleotide mutations in the V region of the 23S rRNA gene can be used for the diagnosis of MRMP. The routine use of macrolide for the treatment of macrolide-sensitive Mycoplasma pneumoniae (MSMP) infections can get good effect, but the effects are limited for severe MRMP infections. Additional corticosteroids may be required for the treatment of severe MRMP infections in children in China during the era of MRMP.

Recent Trend of Antimicrobial Susceptibility among Mycoplasma pneumoniae Isolated from Japanese Children

Macrolide-resistant Mycoplasma pneumoniae (MRMP) infections have become increasingly prevalent, especially in East Asia. Whereas MRMP strains have point mutations that are implicated in conferring resistance, monitoring the antibiotic susceptibility of M. pneumoniae and identifying mutations in the resistant strains is crucial for effective disease management. Therefore, we investigated antimicrobial susceptibilities among M. pneumoniae isolates obtained from Japanese children since 2011. To establish the current susceptibility trend, we analyzed the minimum inhibitory concentrations (MICs) of M. pneumoniae in recent years (2017−2020) in comparison with past data. Our observation of 122 M. pneumoniae strains suggested that 76 were macrolide-susceptible M. pneumoniae (MSMP) and 46 were macrolide-resistant. The MIC ranges (µg/mL) of clarithromycin (CAM), azithromycin (AZM), tosufloxacin (TFLX), and minocycline (MINO) to all M. pneumoniae isolates were 0.001−>128, 0.00012−>128, 0.25−0.5, and 0.125−4 µg/mL, respectively. None of the strains was resistant to TFLX or MINO. The MIC distributions of CAM and AZM to MSMP and MINO to all M. pneumoniae isolates were significantly lower, but that of TFLX was significantly higher than that reported in all previous data concordant with the amount of recent antimicrobial use. Therefore, continuation of appropriate antimicrobial use for M. pneumoniae infection is important.

Association of Intrauterine Microbes with Endometrial Factors in Intrauterine Adhesion Formation and after Medicine Treatment

Intrauterine adhesions (IUAs) have caused serious harm to women’s reproductive health. Although emerging evidence has linked intrauterine microbiome to gynecological diseases, the association of intrauterine microbiome with IUA, remains unknown. We performed metagenome-wide association, metabolomics, and transcriptomics studies on IUA and non-IUA uteri of adult rats to identify IUA-associated microbial species, which affected uterine metabolites and endometrial transcriptions. A rat model was used with one side of the duplex uterus undergoing IUA and the other remaining as a non-IUA control. Both 16S rRNA sequencing and metagenome-wide association analysis revealed that instead of Mycoplasmopsis specie in genital tract, murine lung pathogen Mycoplasmopsispulmonis markedly increased in IUA samples and displayed a distinct positive interaction with the host immune system. Moreover, most of the IUA-enriched 58 metabolites positively correlate with M.pulmonis, which inversely correlates with a mitotic progression inhibitor named 3-hydroxycapric acid. A comparison of metabolic profiles of intrauterine flushing fluids from human patients with IUA, endometritis, and fallopian tube obstruction suggested that rat IUA shared much similarity to human IUA. The endometrial gene Tenascin-N, which is responsible for extracellular matrix of wounds, was highly up-regulated, while the key genes encoding parvalbumin, trophectoderm Dkkl1 and telomerase involved in leydig cells, trophectoderm cells, activated T cells and monocytes were dramatically down-regulated in rat IUA endometria. Treatment for rat IUA with estrogen (E2), oxytetracycline (OTC), and a traditional Chinese patent medicine GongXueNing (GXN) did not reduce the incidence of IUA, though inflammatory factor IL-6 was dramatically down-regulated (96–86%) with all three. Instead, in both the E2 and OTC treated groups, IUA became worse with a highly up-regulated B cell receptor signaling pathway, which may be associated with the significantly increased proportions of Ulvibacter or Staphylococcus. Our results suggest an association between intrauterine microbiota alterations, certain uterine metabolites, characteristic changes in endometrial transcription, and IUA and the possibility to intervene in IUA formation by targeting the causal factors, microbial infection, and Tenascin-like proteins.

Global prevalence of resistance to macrolides in Mycoplasma pneumoniae: a systematic review and meta-analysis

OBJECTIVES

To determine the prevalence of resistance to macrolides in Mycoplasma pneumoniae worldwide.

METHODS

Prior to 12 December 2020, PubMed, Web of Science, Scopus and Embase databases were searched for epidemiological studies of M. pneumoniae resistance. Two reviewers independently extracted data from included studies. The extracted data include sampling population, total sampling number, the number of resistant strains and the molecular subtype of resistant strains. The estimate of resistance prevalence was calculated using the random-effects model.

RESULTS

A total of 17 873 strains were obtained from five continents and reported in 98 investigations between 2000 and 2020, with 8836 strains characterized as macrolide resistant. In summary, macrolide-resistant M. pneumoniae was most common in Asia (63% [95% CI 56, 69]). In Europe, North America, South America and Oceania, the prevalence was 3% [2, 7], 8.6% [6, 11], 0% and 3.3%, respectively. Over the last 20 years, the prevalence of macrolide-resistant M. pneumoniae has remained high in China (81% [73, 87]), with a significant increasing trend in South Korea (4% [1, 9] to 78% [49, 93], P < 0.0001). Furthermore, a point mutation at 2063 from A to G was mostly related to M. pneumoniae macrolide resistance. In terms of clinical outcomes, longer cough (mean difference [MD]: 2.93 [0.26, 5.60]) and febrile days (MD: 1.52 [1.12, 1.92]), and prolonged hospital stays (MD: 0.76 [0.05, 1.46]) might be induced by macrolide-resistant M. pneumoniae pneumonia.

CONCLUSIONS

The incidence of macrolide-resistant M. pneumoniae varies globally, with eastern Asia having a greater degree of resistance. However, attention is also required in other areas, and antibiotic alternatives should be considered for treatment in high-prevalence countries.

Development of a Rapid and Efficient RPA-CRISPR/Cas12a Assay for Mycoplasma pneumoniae Detection

Mycoplasma pneumoniae (MP) is a one of most common pathogen in causing respiratory infection in children and adolescents. Rapid and efficient diagnostic methods are crucial for control and treatment of MP infections. Herein, we present an operationally simple, rapid and efficient molecular method for MP identification, which eliminates expensive instruments and specialized personnel. The method combines recombinase polymerase amplification (RPA) with clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated proteins (Cas) 12a-based detection, with an optimal procedure less than 1 h from sample to result including DNA extraction (25 min), RPA reaction (39°C for 15-20 min), CRISPR/Cas12a detection (37°C for 10 min) and visual detection by naked eyes (2 min). This diagnostic method shows high sensitivity (two copies per reaction) and no cross-reactivity against other common pathogenic bacteria. Preliminary evaluation using 201 clinical samples shows sensitivity of 99.1% (107/108), specificity of 100% (93/93) and consistency of 99.5% (200/201), compared with real-time PCR method. The above data demonstrate that our developed method is reliable for rapid diagnosis of MP. In conclusion, the RPA-CRISPR/Cas12a has a great potential to be as a useful tool for reliable and quick diagnosis of MP infection, especially in primary hospitals with limited conditions.

Detection and Prevalence of Macrolide and Fluoroquinolone Resistance in Mycoplasma genitalium in Badalona, Spain

Macrolide and fluoroquinolone resistance (MLr/FQr) in Mycoplasma genitalium (MG) infections is concerning worldwide. Current guidelines recommend performing MLr detection in MG-positive cases to adjust antimicrobial therapy. We aimed to evaluate the usefulness of PCR followed by pyrosequencing for MLr detection in comparison with a one-step commercial assay and to assess the prevalence of MLr and FQr in Badalona, Spain. A total of 415 MG-positive samples by Allplex STI-7 (Seegene) were analyzed for MLr detection by pyrosequencing. From those, 179 samples were further analyzed for MG and MLr by ResistancePlus^® MG kit (SpeeDx) and 100 of them also for fluoroquinolone resistance (FQr) by sequencing the parC gene. Regarding MG detection, Allplex and Resistance Plus^® showed an overall agreement of 87%, but this value rose to 95.4% if we compare them for MLr detection. Prevalence of MLr was 23.1% in Badalona, but this rate increased to 73.7% in the HIV-positive patients cohort. FQr detection showed 3% of resistant strains. Pyrosequencing is a convenient and cheap technique for MLr detection, but one-step tools should be considered in high-throughput laboratories. Despite the fact that MLr remained moderate and FQr was low in our study, simultaneous MG and MLr detection would improve patient’s management applying resistance-guided treatment strategies.

Recent Trends in the Epidemiology, Diagnosis, and Treatment of Macrolide-Resistant Mycoplasma pneumoniae

Among Mycoplasma pneumoniae (MP) is one of the major pathogens causing lower respiratory tract infection. Macrolide-resistant Mycoplasma pneumoniae (MRMP) isolates have been increasing and has become a global concern, especially in East Asian countries. This affects the treatment of MP infection; that is, some patients with MRMP infections fever cannot be controlled despite macrolide therapy. Therefore, alternative therapies, including secondary antimicrobials, including tetracyclines, fluoroquinolones, or systemic corticosteroids, were introduced. However, there are insufficient data on these alternative therapies. Thus, this article provides reviews of the recent trends in the epidemiology, diagnosis, and treatment of MRMP.

The value of CT radiomic in differentiating mycoplasma pneumoniae pneumonia from streptococcus pneumoniae pneumonia with similar consolidation in children under 5 years

OBJECTIVE

To investigate the value of CT radiomics in the differentiation of mycoplasma pneumoniae pneumonia (MPP) from streptococcus pneumoniae pneumonia (SPP) with similar CT manifestations in children under 5 years.

METHODS

A total of 102 children with MPP (n = 52) or SPP (n = 50) with similar consolidation and surrounding halo on CT images in Qilu Hospital and Qilu Children's Hospital between January 2017 and March 2022 were enrolled in the retrospective study. Radiomic features of the both lesions on plain CT images were extracted including the consolidation part of the pneumonia or both consolidation and surrounding halo area which were respectively delineated at region of interest (ROI) areas on the maximum axial image. The training cohort (n = 71) and the validation cohort (n = 31) were established by stratified random sampling at a ratio of 7:3. By means of variance threshold, the effective radiomics features, SelectKBest and least absolute shrinkage and selection operator (LASSO) regression method were employed for feature selection and combined to calculate the radiomics score (Rad-score). Six classifiers, including k-nearest neighbor (KNN), support vector machine (SVM), extreme gradient boosting (XGBoost), random forest (RF), logistic regression (LR), and decision tree (DT) were used to construct the models based on radiomic features. The diagnostic performance of these models and the radiomic nomogram was estimated and compared using the area under the receiver operating characteristic (ROC) curve (AUC), and the decision curve analysis (DCA) was used to evaluate which model achieved the most net benefit.

RESULTS

RF outperformed other classifiers and was selected as the backbone in the classifier with the consolidation + the surrounding halo was taken as ROI to differentiate MPP from SPP in validation cohort. The AUC value of MPP in validation cohort was 0.822, the sensitivity and specificity were 0.81 and 0.81, respectively.

CONCLUSION

The RF model has the best classification efficiency in the identification of MPP from SPP in children, and the ROI with both consolidation and surrounding halo is most suitable for the delineation.

Macrolide Resistance, Clinical Features, and Cytokine Profiles in Taiwanese Children With Mycoplasma pneumoniae Infection

Background

The factors that predict the progression of Mycoplasma pneumoniae infection remain inconclusive. Therefore, we investigated macrolide resistance prevalence, M pneumoniae genotype, and clinical characteristics of childhood M pneumoniae respiratory tract infections in Taiwan.

Methods

A total of 295 children hospitalized with respiratory tract infections with positive serological M pneumoniae immunoglobulin M test results were enrolled in this 3-year prospective study. Oropharyngeal swabs were obtained for M pneumoniae cultures and polymerase chain reaction tests. All M pneumoniae specimens were further characterized by P1 typing, multilocus variable-number tandem-repeat analysis (MLVA), and macrolide resistance genotyping. The clinical characteristics and blood cytokine profiles were analyzed accordingly.

Results

Of 138 M pneumoniae specimens, type I P1 was the predominant (136 of 138, 98.6%). The MLVA type P (4-4-5-7-2) was the leading strain (42 of 138, 30.4%), followed by type J, U, A, and X. The overall macrolide-resistant rate was 38.4% (53 of 138); the resistance rate increased dramatically yearly: 10.6% in 2017, 47.5% in 2018, and 62.5% in 2019 (P < .001). All macrolide-resistant M pneumoniae (MRMP) harbored the A2063G mutation and were MLVA type 4-5-7-2 (49 of 53, 92.5%), especially type U and X. No significant differences in clinical symptoms, duration of hospital stay, and radiographic findings were identified among patients between MRMP and macrolide-sensitive M pneumoniae (MSMP) groups. Patients with MRMP infection had more febrile days before and during hospitalization and higher interleukin (IL)-13 and IL-33 levels than patients with MSMP infection (P < .05).

Conclusions

Macrolide-resistant M pneumoniae surged in Taiwan throughout the study period, but macrolide resistance was not a determinant factor of clinical severity.

Update on the Epidemiology of Macrolide-Resistant Mycoplasma pneumoniae in Europe: A Systematic Review

Macrolide-resistant Mycoplasma pneumoniae (MR-MP) infections cause upper and lower respiratory tract infections in both children and adults, and are characterized by a longer duration of symptoms. Here, we undertook a systematic review of studies on MR-MP in Europe. The review meets PRISMA guidelines. The PubMed, Scopus, and Science Direct databases were searched using suitable keywords to identify relevant studies published from 2010 to 2021; 21 studies were included. Overall, a low level of MR-MP spread was reported in Europe. MR-MP spread increased during epidemic waves registered in Europe, particularly in Italy and Scotland, where the highest MR-MP infection rates were registered during the 2010–2011 epidemic. By contrast, no MR-MP infections were reported in Finland and the Netherlands. Continued monitoring of MR-MP in Europe is needed to maintain the low rates of infection. Moreover, a coordinated and structured pan-European surveillance program adequate for public health surveillance is advisable, with the purpose of containing the spread of antimicrobial resistance.

Consideration in treatment decisions for refractory Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is the most common cause of childhood bacterial pneumonia. Although macrolide is known to be effective as a first-line therapy, the proportion of macrolide resistance in MP pneumonia has strikingly increased during recent 2 decades in East Asia. This is challenging to physicians since they have to decide more often whether to use secondary treatment. Diagnostic methods to detect macrolide-resistance of MP are currently not available in Korean hospitals. Even in the diagnosis of MP infection, both serologic and molecular test have limitation: inability to differentiate current illness from carriage or asymptomatic infection. Combining these 2 diagnostic methods and excluding infection caused by other respiratory pathogens allow a more reliable diagnosis. This effort is even more demanding in recent years to keep children from unnecessary exposure to secondary antibiotics. Although several observational studies have reported that tetracycline and fluoroquinolone, which are considered in the treatment of refractory MP pneumonia, have efficacy of shortening the duration of fever and respiratory symptoms, those findings need to be proven by well-designed prospective studies. The use of tetracycline and fluoroquinolone in children is generally tolerable, as supported by many observational data. However, since concerns about side effects still remain, careful consideration about benefits and risks is needed to decide their use.

[Detection of drug-resistance genes of Mycoplasma pneumoniae in bronchoalveolar lavage fluid of children with refractory Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To study the drug resistance of Mycoplasma pneumoniae (MP) in the bronchoalveolar lavage fluid (BALF) of children with refractory Mycoplasma pneumoniae pneumonia (RMPP) and the distribution of drug-resistance genes, as well as the association of alleles at 2063 locus of 23SrRNA V region central ring with resistance to antimicrobial drugs.

METHODS

BALF specimens were collected from 245 children with RMPP who were admitted to the Children's Hospital Affiliated to Zhengzhou University from March 2016 to December 2020. A rapid cultured drug sensitivity assay was used to detect the resistance of MP isolates to nine commonly used antimicrobial drugs. The real-time PCR was used to measure MP DNA. The direct sequencing was used to detect gene mutations in MP 23SrRNA V region central ring.

RESULTS

Among the 245 BALF specimens, 207 tested positive for MP DNA, with a positive rate of 84.5%. The results of drug susceptibility test showed that the children with RMPP had a resistance rate of > 70% to macrolide antimicrobial drugs, with the highest resistance rate to clarithromycin, followed by roxithromycin, clindamycin, acetylspiramycin, erythromycin, and azithromycin, and these children had a resistance rate of < 5% to quinolone antimicrobial drugs. Among the 207 MP DNA-positive specimens, 41 (19.8%) had no drug-resistance gene mutations and 166 (80.2%) had drug-resistance gene mutations, among which 154 (74.4%) had an A→G mutation at 2063 locus of 23SrRNA V region central ring, 7 (3.4%) had an A→G mutation at 2064 locus, and 5 (2.4%) had mutations in both 2063 and 2064 loci. Among the 166 specimens with point mutations of the MP 23SrRNA gene, 159 (95.8%) had point mutations at 2063 locus. The A→G point mutation at 2063 locus of 23SrRNA V region central ring had a great impact on resistance to macrolide antimicrobial drugs. There was a significant difference in the distribution of alleles at 2063 locus between the children with resistance to clarithromycin, roxithromycin, clindamycin, acetylspiramycin, erythromycin, and azithromycin (P < 0.05).

CONCLUSIONS

MP in the BALF of children with RMPP has a relatively high resistance rate to macrolide antimicrobial drugs. Resistance to macrolide antimicrobial drugs is closely associated with the A→G point mutation in the 23SrRNA gene, and the point mutation at 2063 locus of 23SrRNA V region central ring may affect the drug-resistance mechanism of MP.

[Detection of drug-resistance genes of Mycoplasma pneumoniae in bronchoalveolar lavage fluid of children with refractory Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To study the drug resistance of Mycoplasma pneumoniae (MP) in the bronchoalveolar lavage fluid (BALF) of children with refractory Mycoplasma pneumoniae pneumonia (RMPP) and the distribution of drug-resistance genes, as well as the association of alleles at 2063 locus of 23SrRNA V region central ring with resistance to antimicrobial drugs.

METHODS

BALF specimens were collected from 245 children with RMPP who were admitted to the Children's Hospital Affiliated to Zhengzhou University from March 2016 to December 2020. A rapid cultured drug sensitivity assay was used to detect the resistance of MP isolates to nine commonly used antimicrobial drugs. The real-time PCR was used to measure MP DNA. The direct sequencing was used to detect gene mutations in MP 23SrRNA V region central ring.

RESULTS

Among the 245 BALF specimens, 207 tested positive for MP DNA, with a positive rate of 84.5%. The results of drug susceptibility test showed that the children with RMPP had a resistance rate of > 70% to macrolide antimicrobial drugs, with the highest resistance rate to clarithromycin, followed by roxithromycin, clindamycin, acetylspiramycin, erythromycin, and azithromycin, and these children had a resistance rate of < 5% to quinolone antimicrobial drugs. Among the 207 MP DNA-positive specimens, 41 (19.8%) had no drug-resistance gene mutations and 166 (80.2%) had drug-resistance gene mutations, among which 154 (74.4%) had an A→G mutation at 2063 locus of 23SrRNA V region central ring, 7 (3.4%) had an A→G mutation at 2064 locus, and 5 (2.4%) had mutations in both 2063 and 2064 loci. Among the 166 specimens with point mutations of the MP 23SrRNA gene, 159 (95.8%) had point mutations at 2063 locus. The A→G point mutation at 2063 locus of 23SrRNA V region central ring had a great impact on resistance to macrolide antimicrobial drugs. There was a significant difference in the distribution of alleles at 2063 locus between the children with resistance to clarithromycin, roxithromycin, clindamycin, acetylspiramycin, erythromycin, and azithromycin (P < 0.05).

CONCLUSIONS

MP in the BALF of children with RMPP has a relatively high resistance rate to macrolide antimicrobial drugs. Resistance to macrolide antimicrobial drugs is closely associated with the A→G point mutation in the 23SrRNA gene, and the point mutation at 2063 locus of 23SrRNA V region central ring may affect the drug-resistance mechanism of MP.

Increased Macrolide Resistance Rate of M3562 Mycoplasma pneumoniae Correlated With Macrolide Usage and Genotype Shifting

To characterize Mycoplasma pneumoniae (MP) strains and to clarify the continuous high rates of macrolide resistance, 1,524 oropharyngeal swabs collected from children in Beijing Children’s Hospital infected with MP during 2016-2019 were analyzed. Among the 1,524 samples, 1,386 harbored mutations associated with macrolide resistance; 1,049 samples were successfully classified into 11 genotypes using multiple locus variable-number tandem-repeat analysis (MLVA). The proportion of the predominant type, M4572, decreased from 84.49 to 70.77% over the time period examined, while that of M3562 increased from 11.63 to 24.67%. Notably, we also found that the frequency of macrolide resistance in M3562 drastically increased, from 60% in 2016 to 93.48% in 2019. Clinical data suggested that the frequency of resistant M3562 was higher in the macrolide usage group than in the nondrug usage group (90.73 vs 53.57%, P<0.0001), while the resistance rate of M4572 was not substantially affected by previous macrolide exposure. These findings validated that antimicrobial application and clonal expansion of resistant MP strains play important roles in the high rates of macrolide resistance.

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.