Macrolide-resistant M. Pneumoniae Research Articles

Detection of Macrolide Resistant Mycoplasma pneumoniae in Children with Lower Respiratory Tract Infection by Sanger Sequencing Targeting Domain V Region of 23S rRNA Gene

Mycoplasma pneumoniae is recognized as the leading cause of community-acquired lower respiratory tract infection in children, accounting for a significant proportion of pediatric mortality. Macrolides are the first-line treatment for M. pneumoniae infections. However, the extensive use of macrolides in clinical practice resulted in the emergence of macrolide-resistant M. pneumoniae (MRMP), which has a negative impact on treatment outcomes. Hence, in the present study, MRMP was determined in hospitalized children with community-acquired pneumonia (CAP). Real-time PCR detected M. pneumoniae in 41 of 348 clinical samples. Sanger sequencing revealed that none of the isolates were associated with the A2063G or A2064G base mutation, which confers macrolide resistance, in domain V of the 23S rRNA gene. Although MRMP was not observed in children with CAP in our study, healthcare practitioners should be vigilant about the potential risk of MRMP infections.

488. Association between the Respiratory Microbiota and Response to Antibiotic Therapy in Children with Macrolide-resistant Mycoplasma pneumoniae Pneumonia

Abstract Background Along with the overuse of macrolides as the empirical treatment for M. pneumoniae infection, macrolide-resistant M. pneumoniae (MRMP) emerged up to 90 prevalence rate in Asian countries. We investigated whether respiratory microbiota at the beginning of hospitalization was associated with disease severity and response to antibiotic treatment in children with MRMP pneumonia. Methods Prospectively enrolled children aged < 18 years with community-acquired pneumonia caused by MRMP from 2017/4-2020/3 at Linkou Chang Gung Memorial Hospital. Oropharyngeal samplings were collected within 48 hours after admission. Total 66 children were included: 23 had not received macrolide or gave response to macrolide (defined as without effective treatment group); 43 needed doxycycline treatment (defined as doxycycline treatment group). Compared the oropharyngeal microbiota between groups using the 16S-rRNA-based sequencing. Patients who were administered antibiotics other than augmentin or Azithromax were excluded. The difference in microbial composition will be examined using microbial community analysis. Statistically significant species for each group were evaluated by the linear discriminant analysis of effect size analysis to identify differentially abundant biomarkers, comparing disease severity scores, CRP and febrile days lasting. Scheme of sample collection and analyses Augmentin with or without Azithromax was the most common antimicrobial agent used. If fever persisted under the impression of suspected MRMP infection, doxycycline was used following three days of Azithromax usage. Scheme of sample collection and analyses Correlation between microbiome and clinical feature. Results Doxycycline treatment group had longer duration of total febrile days (p< 0.001) and total hospitalization days (p=0.002). Without effective treatment group had higher microbial richness, different overall community composition (p< 0.01). The lowest respiratory alpha diversity had prolonged febrile days (p=0.032). Without effective treatment group had more abundant spices or genera. Classification of samples to detect patients with effective treatment or not based on these selected microbiota genera features achieved the ROC curve of 0.86. From the list of most relatively abundant species in MRMP patient without doxycycline, Fusobacterium periodonticum most negatively correlated with total febrile days and severity score. Clinical characteristics of patients enrolled in this study Data were shown as n (%) or mean ± standard deviation. N/A, not applicable. Taxonomic assignment of the all throat swab samples. Fraction of predominant microbiota with a relative abundance of at least 2% at the order level (A) and genus level (B) in all sample. Higher respiratory microbial diversity is associated with MRMP patients without effective treatment than MRMP patients who needed doxycycline treatment Microbial richness base on the different alpha-diversity index in MRMP patients without effective treatment (blue); MRMP patients with doxycycline treatment (red). (A)(B)The box represented the interquartile range (IQR, and the midline represented the median. Tukey’s honest significance test of ANOVA, p<0.05.) (C)Kaplan-Meier (KM) plot of febrile time by respiratory diversity. (D)Principal coordinates analysis (PCoA) for MRMP patients without effective treatment (blue), MRMP patients with doxycycline treatment (red) by Unweighted UniFrac distance. Significant differences were observed between MRMP patients without effective treatment and MRMP patients with doxycycline treatment. A PERMANOVA (α=0.05) with 999 random permutations, p = 0.001. Conclusion Respiratory dysbiosis was associated with persistent fever and disease severity in MRMP pneumonia. In our study, F. periodoticum negatively related to fever duration and disease severity. Compositional differences in the respiratory microbiome are associated with MRMP patients without effective treatment than MRMP patients who needed doxycycline treatment by LEfSE analysis LDA scores revealed differentially abundant bacteria in the respiratory microbiome of without effective treatment (blue) and doxycycline treatment (red) groups at genus level (A) and species level (B).The mean relative abundance of genera at right side. The mean relative abundance of genera at right side. (C) Receiver operating characteristic (ROC) curves of ASVs to predict MRMP patients without effective treatment or who needed doxycycline treatment. Pairwise Spearman rank correlation heat map of significantly different taxa in throat swabs at initial sampling and clinical severity score in MRMP patients without effective treatment/with doxycycline treatment The genus (A) and species (B) level. Genus and species were in rows; the correlation was indicated by color gradient. Disclosures All Authors: No reported disclosures.

Regional and annual patterns in respiratory virus co-infection etiologies and antibiotic prescriptions for pediatric mycoplasma pneumoniae pneumonia.

Mycoplasma pneumoniae (M. pneumoniae) pneumonia is the second-most common cause of community-acquired pneumonia (CAP). This study aimed at investigating into the prevalence of macrolide-resistant M. pneumoniae (MRMP) with respiratory virus co-infection and the antibiotic prescriptions in children with CAP in four provinces in Korea, and to assess the variations in the findings across regions and throughout the year. This prospective study was conducted in 29 hospitals in Korea between July 2018 and June 2020. Among the enrolled 1,063 children with CAP, all 451 patients with M. pneumoniae underwent PCR assays of M. pneumoniae and respiratory viruses, and the presence of point mutations of residues 2063 and 2064 was evaluated. Gwangju-Honam (88.6%) showed the highest prevalence of MRMP pneumonia, while Daejeon-Chungcheong (71.3%) showed the lowest, although the differences in prevalence were not significant (p=0.074). Co-infection of M. pneumoniae pneumonia and respiratory virus was observed in 206 patients (45.4%), and rhinovirus co-infection (101 children; 22.2%) was the most frequent. The prevalence of MRMP pneumonia with respiratory virus co-infection and the antibiotic prescriptions differed significantly among the four provinces (p < 0.05). The monthly rate of MRMP pneumonia cases among all cases of M. pneumoniae pneumonia and tetracycline or quinolone prescriptions did not differ significantly among the four regions (trend p > 0.05) during the study period. The prevalence of M. pneumoniae pneumonia with virus co-infection and antibiotic prescriptions could differ according to region, although the MRMP pneumonia rate showed no difference within Korea.

Mycoplasma pneumoniae detections before and during the COVID-19 pandemic: results of a global survey, 2017 to 2021.

Background Mycoplasma pneumoniae respiratory infections are transmitted by aerosol and droplets in close contact.AimWe investigated global M. pneumoniae incidence after implementation of non-pharmaceutical interventions (NPIs) against COVID-19 in March 2020.MethodsWe surveyed M. pneumoniae detections from laboratories and surveillance systems (national or regional) across the world from 1 April 2020 to 31 March 2021 and compared them with cases from corresponding months between 2017 and 2020. Macrolide-resistant M. pneumoniae (MRMp) data were collected from 1 April 2017 to 31 March 2021.ResultsThirty-seven sites from 21 countries in Europe, Asia, America and Oceania submitted valid datasets (631,104 tests). Among the 30,617 M. pneumoniae detections, 62.39% were based on direct test methods (predominantly PCR), 34.24% on a combination of PCR and serology (no distinction between methods) and 3.37% on serology alone (only IgM considered). In all countries, M. pneumoniae incidence by direct test methods declined significantly after implementation of NPIs with a mean of 1.69% (SD ± 3.30) compared with 8.61% (SD ± 10.62) in previous years (p < 0.01). Detection rates decreased with direct but not with indirect test methods (serology) (–93.51% vs + 18.08%; p < 0.01). Direct detections remained low worldwide throughout April 2020 to March 2021 despite widely differing lockdown or school closure periods. Seven sites (Europe, Asia and America) reported MRMp detections in one of 22 investigated cases in April 2020 to March 2021 and 176 of 762 (23.10%) in previous years (p = 0.04).ConclusionsThis comprehensive collection of M. pneumoniae detections worldwide shows correlation between COVID-19 NPIs and significantly reduced detection numbers.

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

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

Emergence of Macrolide-Resistant Mycoplasma pneumoniae during an Outbreak in a Primary School: Clinical Characterization of Hospitalized Children.

Mycoplasma pneumoniae (M. pneumoniae) is a common causative pathogen of community-acquired pneumonia. Here, we report the development of macrolide resistance during a school outbreak of severe M. pneumoniae infections in southwest Germany. We conducted a case series to assess the clinical and laboratory characteristics of hospitalized children with M. pneumonia infection and the prevalence of macrolide-resistant M. pneumoniae (MRMP) in this patient group. We retrospectively analyzed 23 children with serologically (19 patients) and/or PCR (eight patients) confirmed M. pneumoniae infection between October 2019 and December 2019. Most of the 15 hospitalized patients had lower respiratory tract infection (n = 10) and required oxygen therapy (83%). The median length of hospitalization was 7 days (range 3–10 days). In 8/15 patients (53.3%) azithromycin and in 4/15 (26.6%) clarithromycin treatment was applied. However, among the five patients for which extended molecular characterization was performed, sequencing of 23S rRNA revealed no mutation only in the first case, but development of macrolide resistance A2058G in four subsequent cases. Hence, we identified a cluster of hospitalized patients with emerging MRMP. Further studies are warranted to confirm a potential link between macrolide resistance and disease severity.

Recent acute reduction in macrolide-resistant Mycoplasma pneumoniae infections among Japanese children

IntroductionMycoplasma pneumoniae contributes to numerous pneumonia cases among children and young adults. Therefore, this study aimed to investigate the prevalence of M. pneumoniae infections among Japanese children, occurring since 2008. MethodsNasopharyngeal swab specimens were obtained from all cases, following which real-time PCR was performed to identify M. pneumoniae. Further, the p1 genotypes of isolates were determined using the PCR restriction fragment length polymorphism typing method. ResultsThe annual rate of macrolide-resistant M. pneumoniae (MRMP) infections peaked at 81.8% in 2012 and decreased annually until 2015. Although the infection rate increased to 65.3% in 2016, it decreased again to 14.3% in 2018. Although >90% of isolates harbored the type 1 genotype until 2012, this rate decreased, and approximately 80% harbored p1 genotypes other than type 1 in 2018. Furthermore, the occurrence rate of MRMP among the type 1 isolates was very high (82.4%), whereas that among p1 genotypes other than type 1 was very low (6.5%). ConclusionsMRMP occurrence potentially decreased owing to changes in not only antibiotic usage but also in the distribution of p1 genotype among isolates.

The Prevalence of 23S rRNA Mutations in ML-Resistant M. pneumoniae Isolates to Clarithromycin in Patients with Respiratory Infections.

Mycoplasma pneumoniae is one of the widespread causes of community-acquired pneumonia (CAP). Over recent years, the widespread use of macrolides has led to the emergence of macrolide-resistant M.pneumoniae (MRMP) resulted from mutations at specific positions of domain V of the 23S rRNA gene. We collected 100 samples of throat swabs from patients with respiratory infections. After extraction of DNA from bacterial cell cultured in PPLO broth media using Roche kit (Germany), the PCR was performed on specific samples of M. pneumoniae using specific primers for 23S rRNA gene.Afterwards, for positive samples, minimum inhibitory concentration (MIC) was determined using the broth microdilution with Clarithromycin. Finally, the PCR product was sequenced to detect mutations related to macrolide resistance in domain V of 23S rRNA . According to the analysis of the sequenced PCR product of M. pneumoniae 23S rRNA gene using Clustalw2 online software, one of the samples were shown to have a mutation at A2431G and G2491A positions. The MIC measurement also revealed that all isolates were sensitive to Clarithromycin, and there was no macrolide resistance to Clarithromycin in all isolates. Sequence analysis of the 23S rRNA gene in M. pneumoniae , revealed no macrolide resistance of M. pneumoniae to Clarithromycin. Thus, the use of these antibiotics should be restricted to prevent the development of macrolide-resistant M. pneumoniae in Iran.

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

Mycoplasma pneumoniae is one of the most common bacterial causes of pneumonia. Macrolide-resistant Mpneumoniae (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 Mpneumoniae 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, Mpneumoniae 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. Mpneumoniae 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 Mpneumoniae, and may consider non-macrolide-based therapy for confirmed or non-responding infections in patients who are immunocompromised or hospitalized.

First Detection and Characterization of Macrolide-Resistant Mycoplasma pneumoniae from People with Community-Acquired Pneumonia in Iran.

Objectives: Increasing macrolide resistance of Mycoplasma pneumoniae strains is becoming a public health concern worldwide. Nevertheless, no comprehensive genomic background of circulating isolates is available in our region. We aimed to study the genetic diversity of this microorganism using the multiple-locus variable-number tandem-repeat analysis method and to investigate the relationships between MLVA types and macrolide susceptibility profiles of the isolates. Materials and Methods: A total of 270 patients attending Tehran general university hospitals were included in this study. One throat swab was taken from each patient. M. pneumoniae was identified using culture and PCR assay. Macrolide resistance was determined using the broth microdilution method. The MLVA was performed by amplification of four variable-number tandem-repeat loci. Results: Of 270 specimens, M. pneumoniae was detected in 25.2% (n = 68) and 21.8% (n = 59) samples using PCR and culture, respectively. Approximately 56.9% of isolates were resistant to macrolides. Fifty-one of 59 M. pneumoniae isolates were divided into 6 distinct MLVA types. Conclusion: The macrolide-resistant M. pneumoniae (MRMP) rate in this study was relatively high and most of the MRMP isolates were assigned into the type 4/5/7/2. Since a significant association between MLVA type 4/5/7/2 and macrolide resistance of M. pneumoniae isolates was observed, further monitoring of genetic diversity of MRMP isolates might facilitate better understanding of epidemiology of this microorganism. Besides surveillance of the antibiotic susceptibility might be helpful to make necessary reconsiderations on guidelines for treatment of M. pneumoniae infection.

Allele-specific real-time PCR testing for minor macrolide-resistant Mycoplasma Pneumoniae

BackgroundThe point mutations in 23S rRNA gene of Mycoplasma pneumoniae (M. pneumoniae) can lead to high-level resistance to macrolides. This study aimed to evaluate allele-specific real-time PCR (ASPCR) to detect the resistance-related mutations located at positions A2063G and A2064G of 23S rRNA gene.MethodsWe detected 178 pharyngeal swab specimens and calculated the proportions of resistant and sensitive quasispecies using ASPCR assays. ASPCR assays can detect down to 10 copies of 23S rRNA gene and achieved sensitivities of < 0.1% for A2063G and A2064G. We also compared the findings of ASPCR with the results of nested PCR with sequencing.ResultsOf 178 samples, 164 were found to have M. pneumoniae including 90.85% (149/164) samples with macrolide-resistant M. pneumoniae (MRMP) quasispecies by ASPCR, while 153 were found to be M. pneumoniae-positive including 71.90% (110/153) samples with MRMP quasispecies by nested PCR with sequencing. Of the 164 M. pneumoniae-positive samples, 61.59% (101/164) had the mixed population of wild-type and mutant M. pneumoniae, and 56.44% (57/101) of the latter contained the mutations at low frequency (≤50%).ConclusionASPCR indicated that sensitive and resistant quasispecies coexisted in most of the M. pneumoniae positive samples. The ASPCR was a highly sensitive, accurate and rapid method for detecting the macrolide resistance-associated mutations and it could provide earlier and more drug-resistant information for M. pneumoniae research and the clinical therapy.

Molecular characterization and analysis of Mycoplasma pneumoniae among patients of all ages with community-acquired pneumonia during an epidemic in China

BackgroundAnalysis of the molecular characteristics of isolates is very important for clinical and epidemiological study of community-acquired pneumonia (CAP) caused by Mycoplasma pneumoniae. MethodsBetween 2010 and 2012, an epidemic period, M. pneumoniae was isolated from oropharyngeal swabs of consecutive CAP patients. Minimum inhibitory concentrations of macrolides, 23S rRNA gene sequencing, P1 gene and multilocus variable-number tandem-repeat analysis (MLVA) genotyping was conducted. Results88.3% (181/205) of the isolates were macrolide-resistant M. pneumoniae (MRMP) and all harbored an A2063 G mutation. The strains were clustered into 7 MLVA types, and P1 type 1 and type 2 lineages were co-circulated (86.3% and 13.7%). Compared with adults, no specific MLVA type contributed to higher M. pneumoniae infection in children (p = 0.14). Similar macrolide profile and genotypes of M. pneumoniae was found between outpatients and inpatients. Significant differences in proportion of P1 types and two main MLVA types 4/5/7/2 and 3/5/6/2 were observed between MRMP and macrolide-sensitive M. pneumoniae (MSMP) (p < 0.001). ConclusionsThis study demonstrates a comprehensive profile of M. pneumoniae molecular characterization among CAP patients of all age, and provides more evidences on a correlation between MLVA type 4/5/7/2 and macrolide resistance in the setting of high incidence of MRMP.

Phase-shifting of the transmissibility of macrolide-sensitive and resistant Mycoplasma pneumoniae epidemics in Hong Kong, from 2015 to 2018

Mycoplasma pneumoniae is a threat to public health. This pathogen caused an epidemic in Hong Kong during the years 2015–2018. The reproduction number during the initial epidemic was estimated to be 1.7 for macrolide-resistant M. pneumoniae (MRMP) and 1.4 for macrolide-sensitive M. pneumoniae (MSMP). During 2016–2018, the reproduction number remained stable at around 1.0 for both MRMP and MSMP. Phase-shifting and changes in the leading-status between the transmissibilities of MSMP and MRMP were found.

The Art and Science of Diagnosing Mycoplasma pneumoniae Infection.

Mycoplasma pneumoniae causes a significant burden of disease in children as both upper and lower respiratory tract infections (URTIs and LRTIs). A positive pharyngeal polymerase chain reaction (PCR) or serology for M. pneumoniae can be found in 4–39% of children hospitalized with community-acquired

Clinical Characteristics of Macrolide-Resistant Mycoplasma pneumoniae from Children in Jeju.

Mycoplasma pneumoniae is the major pathogen of community-acquired pneumonia in children. The prevalence of macrolide-resistant M. pneumoniae (MRMP) is important owing to the limited alternative therapies for children. We analyzed 111 M. pneumoniae obtained from 107 children admitted for lower respiratory tract infection at Jeju National University Hospital between 2010 and 2015. Macrolide resistance of M. pneumoniae was searched for using polymerase chain reaction (PCR) and sequencing. Of 107 clinical M. pneumoniae, 11 (10.3%) carried macrolide resistance mutations in the 23S rRNA gene. All macrolide resistance mutations were A2063G transitions. We found an acquired A2063G mutation of M. pneumoniae from a patient during macrolide treatment. Patients' characteristics and clinical severity did not differ between those with MRMP and macrolide-sensitive M. pneumoniae, with the exception of frequent pleural effusion in the MRMP group. The prevalence of MRMP (10.3%) in Jeju Island was relatively lower than those of surrounding countries in East Asia. Previous antimicrobial usage and timing of diagnostic test should be considered when determining of macrolide resistance of M. pneumoniae.

Macrolide Resistance and Its Impacts on M. Pneumoniae Pneumonia in Children: Comparison of Two Recent Epidemics in Korea.

PurposeThe aim of this study was to investigate the change in macrolide resistance rate in pediatric Mycoplasma pneumoniae pneumonia and to evaluate the influence of macrolide-resistant M. pneumoniae (MRMP) on the clinical course of disease, by comparing 2 recent, consecutive epidemics in Korea.MethodsA total of 250 patients with M. pneumoniae pneumonia admitted to a single tertiary hospital were enrolled in this study. Detection of MRMP was based on specific point mutations in domain V of the 23S rRNA gene. The medical records of enrolled patients were reviewed retrospectively, and the clinical courses and laboratory data were compared.ResultsThe macrolide resistance rate of M. pneumoniae was 51.1% (48/94) in the 2011 epidemic, and 87.2% (136/156) in the 2015 epidemic. All MRMP isolates had the A2063G point mutation. In comparison of 2 epidemics, the mean age of patients with M. pneumoniae pneumonia was increased, and the total febrile days and febrile days after initiation of macrolides were prolonged in the 2015 epidemic. Overall severity of MRMP or macrolide-susceptible M. pneumoniae (MSMP) pneumonia over 2 epidemics was not significantly changed. However, the proportion of patients who had a fever lasting more than 72 hours after initiation of macrolides and who received corticosteroid treatment were higher in MRMP pneumonia during 2 epidemics.ConclusionsThe macrolide resistance rate of M. pneumoniae has risen rapidly over 2 recent, consecutive epidemics, and this has been associated with a prolonged clinical course and increased use of corticosteroids to treat pediatric M. pneumoniae pneumonia.

Epidemiology of Mycoplasma pneumoniae Infections in Japan and Therapeutic Strategies for Macrolide-Resistant M. pneumoniae.

Pneumonia caused by Mycoplasma pneumoniae (M. pneumoniae pneumonia) is a major cause of community-acquired pneumonia worldwide. The surveillance of M. pneumoniae pneumonia is important for etiological and epidemiological studies of acute respiratory infections. In Japan, nation-wide surveillance of M. pneumoniae pneumonia has been conducted as a part of the National Epidemiological Surveillance of Infectious Diseases (NESID) program. This surveillance started in 1981, and significant increases in the numbers of M. pneumoniae pneumonia patients were noted in 1984, 1988, 2006, 2010, 2011, 2012, and 2015. The epidemics in 2011 and 2012 were particularly widespread and motivated researchers to conduct detailed epidemiological studies, including genotyping and drug resistance analyses of M. pneumoniae isolates. The genotyping studies based on the p1 gene sequence suggested that the p1 gene type 1 lineage has been dominant in Japan since 2003, including the epidemic period during 2011–2012. However, more detailed p1 typing analysis is required to determine whether the type 2 lineages become more relevant after the dominance of the type 1 lineage. There has been extensive research interest in implications of the p1 gene types on the epidemiology of M. pneumoniae infections. Serological characterizations of sera from patients have provided a glimpse into these associations, showing the presence of type specific antibody in the patient sera. Another important epidemiological issue of M. pneumoniae pneumonia is the emergence of macrolide-resistant M. pneumoniae (MRMP). MRMPs were noted among clinical isolates in Japan after 2000. At present, the isolation rate of MRMPs from pediatric patients is estimated at 50–90% in Japan, depending on the specific location. In view of the situation, Japanese societies have issued guiding principles for treating M. pneumoniae pneumonia. In these guiding principles, macrolides are still recommended as the first-line drug, however, if the fever does not subside in 48–72 h from first-line drug administration, a change of antibiotics to second-line drugs is recommended.

Mycoplasma pneumoniae in children: carriage, pathogenesis, and antibiotic resistance.

Both the diagnosis and treatment of Mycoplasma pneumoniae infections in children are currently facing two main challenges: a relatively high carriage in asymptomatic children, and a worldwide increase in macrolide-resistant M. pneumoniae (MRMP). This review focuses on the scientific and clinical implications of these crucial issues. Recent studies have indicated that the prevalence of M. pneumoniae in the upper respiratory tract is similar among asymptomatic, healthy children and children with a symptomatic respiratory tract infection, and that current diagnostic procedures for M. pneumoniae are unable to differentiate between bacterial carriage and infection. It is therefore possible that the burden of M. pneumoniae-associated disease is overestimated. Another phenomenon that has an important impact on the treatment of M. pneumoniae infections is the rapid worldwide emergence of MRMP isolates. The current diagnostic procedures for M. pneumoniae cannot discern between bacterial carriage and infection in a clinically relevant time frame. It is therefore imperative that these procedures be modified such as to unambiguously detect symptomatic M. pneumoniae infections. Moreover, the emergence of MRMP necessitates the application of methods to detect macrolide resistance as well as the implementation of restrictive policies regarding the use of macrolides.

Rapid Effectiveness of Minocycline or Doxycycline Against Macrolide-Resistant Mycoplasma pneumoniae Infection in a 2011 Outbreak Among Japanese Children

Mycoplasma pneumoniae is a major pathogen causing community-acquired pneumonia in children and young adults. Outbreaks typically occur at intervals of several years. In 2011, a widespread outbreak was associated with macrolide-resistant M. pneumoniae (MRMP) in Japanese children, often those of school age. Two hundred fifty-eight children were diagnosed with M. pneumoniae-associated pneumonia based on chest radiography, real-time polymerase chain reaction (PCR), and antibody titers between January and December 2011. Mycoplasma pneumoniae cultures obtained from nasopharyngeal samples using appropriate broth were subjected to real-time PCR, by which decreases in M. pneumoniae in patients treated with minocycline (MIN), doxycycline (DOX), or tosufloxacin (TFX) were calculated. Mutations of the 23S ribosomal RNA gene that confer high resistance to macrolides in M. pneumoniae were identified by DNA sequencing. Among 202 M. pneumoniae isolates from M. pneumoniae-associated pneumonia patients, 176 (87.1%) were MRMP. Macrolide-resistant M. pneumoniae infection was significantly related to school age (P < .01) and initial administration of macrolides (P < .01). Minocycline or DOX (n = 125) or TFX or levofloxacin (n = 15) was used for definitive treatment of MRMP patients. Minocycline or DOX was significantly more effective than TFX (P ≤ .05) in achieving defervescence within 24 hours and in decreasing numbers of M. pneumoniae DNA copies 3 days after initiation. Macrolides are inappropriate as first-choice agents against MRMP in terms of shortening the clinical course and decreasing M. pneumoniae. Control and prevention of MRMP outbreaks in children require early decreases in M. pneumoniae as well as improvement of clinical findings.