Characterization of macrolide resistance of Mycoplasma pneumoniae in children in Shenzhen, China

Challenges in the treatment of pediatric Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is an important cause of community-acquired pneumonia in children and young adolescents. Despite macrolide antibiotics effectiveness as a first-line therapy, persistence of fever and/or clinical deterioration sometimes may complicate treatment and may even lead to severe systemic disease. To date, there is no consensus on alternative treatment options, optimal dosage, and duration for treating severe, progressive, and systemic MP pneumonia after macrolide treatment failure. Macrolide-resistant MP pneumonia and refractory MP pneumonia are the two major complex conditions that are clinically encountered. Currently, the vast majority of MP isolates are resistant to macrolides in East Asia, especially China, whereas in Europe and North America, whereas in Europe and North America prevalence is substantially lower than in Asia, varying across countries. The severity of pneumonia and extrapulmonary presentations may reflect the intensity of the host's immune reaction or the dissemination of bacterial infection. Children infected with macrolide-resistant MP strains who receive macrolide treatment experience persistent fever with extended antibiotic therapy and minimal decrease in MP-DNA load. Alternative second-line agents such as tetracyclines (doxycycline or minocycline) and fluoroquinolones (ciprofloxacin or levofloxacin) may lead to clinical improvement after macrolide treatment failure in children. Refractory MP pneumonia reflects a deterioration of clinical and radiological findings due to excessive immune response against the infection. Immunomodulators such as corticosteroids and intravenous immunoglobulin (IVIG) have shown promising results in treatment of refractory MP pneumonia, particularly when combined with appropriate antimicrobials. Corticosteroid-resistant hyperinflammatory MP pneumonia represents a persistent or recrudescent fever despite corticosteroid therapy with intravenous methylprednisolone at standard dosage.

CONCLUSION

 This report summarizes the clinical significance of macrolide-resistant and refractory MP pneumonia and discusses the efficacy and safety of alternative drugs, with a stepwise approach to the management of MP pneumonia recommended from the viewpoint of clinical practice.

WHAT IS KNOWN

• Although MP pneumonia is usually a benign self-limited infection with response macrolides as first line therapy, severe life-threatening cases may develop if additional treatment strategies are not effectively implemented. • Macrolide-resistant and refractory MP pneumonia are two conditions that may complicate the clinical course of MP pneumonia, increasing the risk for exacerbation and even death.

WHAT IS NEW

• This report summarizes the clinical relevance of macrolide-resistant and refractory MP pneumonia and discusses the efficacy and safety of alternative drug therapies. • A practical stepwise approach to the management of MP pneumonia is developed based on a comprehensive analysis of existing evidence and expert opinion.

Identification of mycoplasma pneumonia in children based on fusion of multi-modal clinical free-text description and structured test data

Mycoplasma pneumonia may lead to hospitalizations and pose life-threatening risks in children. The automated identification of mycoplasma pneumonia from electronic medical records holds significant potential for improving the efficiency of hospital resource allocation. In this study, we proposed a novel method for identifying mycoplasma pneumonia by integrating multi-modal features derived from both free-text descriptions and structured test data in electronic medical records. Our approach begins with the extraction of free-text and structured data from clinical records through a systematic preprocessing pipeline. Subsequently, we employ a pre-trained transformer language model to extract features from the free-text, while multiple additive regression trees are used to transform features from the structured data. An attention-based fusion mechanism is then applied to integrate these multi-modal features for effective classification. We validated our method using clinic records of 7157 patients, retrospectively collected for training and testing purposes. The experimental results demonstrate that our proposed multi-modal fusion approach achieves significant improvements over other methods across four key performance metrics.

Observational retrospective clinical study on clinical features of macrolide-resistant Mycoplasma pneumoniae pneumonia in Chinese pediatric cases

This study aimed to investigate differences in clinical characteristics and laboratory findings between children infected with Macrolide-Sensitive Mycoplasma pneumoniae (MSMP) and Macrolide-Resistant Mycoplasma pneumoniae (MRMP). Additionally, the research sought to identify laboratory markers for rapidly distinguishing refractory Mycoplasma pneumoniae pneumonia (RMPP) from ordinary Mycoplasma pneumoniae pneumonia (OMPP). In total, 265 Mycoplasma pneumoniae (MP) patients were included, with MRMP identified by specific point mutations in domain V of the 23S rRNA gene. A retrospective analysis compared the clinical courses and laboratory data, revealing that MRMP patients experienced prolonged febrile days (P = 0.004), elevated CRP levels (P < 0.001), and higher MP DNA loads than MSMP patients (P = 0.037). Based on clinical symptoms, MRMP was divided into RMPP (n = 56) and OMPP (n = 70), with RMPP demonstrating significantly increased IL-18, community-acquired respiratory distress syndrome (CARDS) toxins in nasopharyngeal aspirate, and serum CRP levels (P < 0.001; P = 0.006; P < 0.001). In conclusion, timely recognition of RMPP is crucial for enhancing prognosis. The identification of MRMP, coupled with proinflammatory cytokines such as IL-18, CARDS toxins, and CRP, emerges as promising markers with the potential to contribute significantly to diagnostic accuracy and prognosis assessment.

Characteristics of the Mycoplasma pneumoniae Epidemic from 2019 to 2020 in Korea: Macrolide Resistance and Co-Infection Trends

Mycoplasma pneumoniae, a major etiological agent of community-acquired pneumonia, exhibits distinct cyclic epidemic patterns recurring every three to five years. Several cases of co-infection with severe acute respiratory syndrome coronavirus 2 have been reported globally, resulting in unfavorable clinical manifestations. This study investigated the epidemiological features of the recent M. pneumoniae outbreak (May 2019-April 2020) using retrospective data from the last five years. Molecular test data for macrolide resistance and co-infection were obtained from the Seegene Medical Foundation. National medical expenditure and hospitalization rates were analyzed using data from The Health Insurance Review and Assessment Service of Korea. The macrolide resistance rate was 69.67%, peaking at 71.30% during the epidemic period, which was considerably higher than the 60.89% rate during non-epidemic periods. The co-infection rate with other respiratory pathogens was 88.49%; macrolide-resistant M. pneumoniae strains showed a 2.33% higher co-infection rate than the susceptible strains. The epidemic period had 15.43% higher hospitalization and 78.27% higher medical budget expenditure per patient than non-epidemic periods. The increased rates of macrolide resistance and co-infection observed in macrolide-resistant M. pneumoniae during the epidemic period highlight the importance of monitoring future outbreaks, especially considering macrolide resistance and the risk of co-infection with other pathogens.

Severe problem of macrolides resistance to common pathogens in China

With the widespread use of macrolide antibiotics in China, common pathogens causing children's infections, such as Streptococcus pneumoniae, Streptococcus (including Group A streptococcus, Group B streptococcus), Staphylococcus aureus, Bordetella pertussis, and Mycoplasma pneumoniae, have shown varying degrees of drug resistance. In order to provide such problem and related evidence for rational use of antibiotics in clinic, we reviewed the drug resistance of common bacteria to macrolides in children recent 20 years.

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.

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.

Clinical significance of respiratory virus coinfection in children with Mycoplasma pneumoniae pneumonia

BACKGROUND

The prevalence of refractory Mycoplasma pneumoniae (MP) pneumonia has been increasing. However, few studies have investigated the impact of respiratory virus coinfection in patients with MP pneumonia, and their results have been inconclusive. This study aimed to investigate the impact of respiratory virus coinfection in children hospitalized with MP pneumonia.

METHODS

This study enrolled 145 children hospitalized with MP pneumonia between May 2019 and March 2020. The patients were divided into two groups: the respiratory virus coinfection and non-coinfection groups. All the children underwent polymerase chain reaction testing for respiratory virus infection. Information on clinical, laboratory, and radiologic findings were obtained retrospectively via medical chart reviews.

RESULTS

Children in the respiratory virus coinfection group were younger than those in the non-coinfection group. Respiratory virus coinfection in children hospitalized with MP pneumonia was significantly associated with persistence of fever more than 6 days (adjusted odds ratio [aOR], 2.394; 95% confidence interval [95% CI], 1.172-4.892), severe pneumonia (aOR, 4.602; 95% CI, 1.154-18.353), and poor response to the stepwise approach for MP pneumonia (aOR, 4.354; 95% CI, 1.374-13.800). In addition, higher levels of liver enzymes and lactate dehydrogenase at admission were associated with respiratory virus coinfection in children with MP pneumonia.

CONCLUSIONS

The results of this study suggest that respiratory virus coinfection in children hospitalized with MP pneumonia may be associated with refractory MP pneumonia.

Mycoplasma pneumoniae among Chinese Outpatient Children with Mild Respiratory Tract Infections during the Coronavirus Disease 2019 Pandemic

Mycoplasma pneumoniae is a common pathogen causing respiratory disease in children. We sought to investigate the epidemiology of M. pneumoniae among outpatient children with mild respiratory tract infections (RTIs) during the coronavirus disease 2019 (COVID-19) pandemic. Eligible patients were prospectively enrolled from January 2020 to June 2021. Throat swabs were tested for M. pneumoniae RNA. M. pneumoniae IgM was tested by a colloidal gold assay. Macrolide resistance and the effect of the COVID-19 countermeasures on M. pneumoniae prevalence were assessed. Symptom scores, treatments, and outcomes were evaluated. Eight hundred sixty-two eligible children at 15 centers in China were enrolled. M. pneumoniae was detected in 78 (9.0%) patients. Seasonally, M. pneumoniae peaked in the first spring and dropped dramatically to extremely low levels over time until the next summer. Decreases in COVID-19 prevalence were significantly associated with decreases in M. pneumoniae prevalence (r = 0.76, P = 0.001). The macrolide resistance rate was 7.7%. The overall sensitivity and specificity of the colloidal gold assay used in determining M. pneumoniae infection were 32.1% and 77.9%, respectively. No more benefits for improving the severity of symptoms and outcomes were observed in M. pneumoniae-infected patients treated with a macrolide than in those not treated with a macrolide during follow-up. The prevalences of M. pneumoniae and macrolide resistance in outpatient children with mild RTIs were at low levels in the early stage of the COVID-19 pandemic but may have rebounded recently. The colloidal gold assay for M. pneumoniae IgM may be not appropriate for diagnosis of M. pneumoniae infection. Macrolides should be used with caution among outpatients with mild RTIs. IMPORTANCE This is the first and largest prospective, multicenter, active, population-based surveillance study of the epidemiology of Mycoplasma pneumoniae among outpatient children with mild respiratory tract infections (RTIs) during the COVID-19 pandemic. Nationwide measures like strict face mask wearing and restrictions on population movement implemented to prevent the spread of COVID-19 might also effectively prevent the spread of M. pneumoniae. The prevalence of M. pneumoniae and the proportion of drug-resistant M. pneumoniae isolates in outpatient children with mild RTIs were at low levels in the early stage of the COVID-19 pandemic but may have rebounded recently. The colloidal gold assay for M. pneumoniae IgM may be not appropriate for screening and diagnosis of M. pneumoniae infection. Macrolides should be used with caution among outpatients with mild RTIs.

Macrolide-Resistant Mycoplasma pneumoniae Infections in Children, Ohio, USA

Emergence of macrolide-resistant Mycoplasma pneumoniae (MRMp) challenges empiric macrolide therapy. Our goal was to determine MRMp rates and define characteristics of children infected with macrolide-sensitive M. pneumoniae (MSMp) versus MRMp in Ohio, USA. We cultured PCR-positive M. pneumoniae specimens and sequenced M. pneumoniae-positive cultures to detect macrolide resistance mutations. We reviewed medical records to compare characteristics of both groups. We identified 14 (2.8%) MRMp and 485 (97.2%) MSMp samples. Patients in these groups had similar demographics and clinical characteristics, but patients with MRMp had longer hospitalizations, were more likely to have received previous macrolides, and were more likely to have switched to alternative antimicrobial drugs. MRMp-infected patients also had ≈5-fold greater odds of pediatric intensive care unit admission. Rates of MRMp infections in children in central Ohio are low, but clinicians should remain aware of the risk for severe illness caused by these pathogens.

[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.

Macrolide-Resistant Mycoplasma pneumoniae Infections in Pediatric Community-Acquired Pneumonia

A high prevalence rate of macrolide-resistant Mycoplasma pneumoniae (MRMP) has been reported in Asia. We performed a systematic review and meta-analysis to investigate the effect of macrolide resistance on the manifestations and clinical judgment during M. pneumoniae infections. We found no difference in clinical severity between MRMP and macrolide-sensitive Mycoplasma pneumoniae (MSMP) infections. However, in the pooled data, patients infected with MRMP had a longer febrile period (1.71 days), length of hospital stay (1.61 day), antibiotic drug courses (2.93 days), and defervescence time after macrolide treatment (2.04 days) compared with patients infected with MSMP. The risk of fever lasting for >48 hours after macrolide treatment was also significantly increased (OR 21.24), and an increased proportion of patients was changed to second-line treatment (OR 4.42). Our findings indicate diagnostic and therapeutic challenges after the emergence of MRMP. More precise diagnostic tools and clearly defined treatment should be appraised in the future.

Macrolide-Resistant Mycoplasma pneumoniae in the United States as Determined from a National Surveillance Program

There are sparse data to indicate the extent that macrolide-resistant Mycoplasma pneumoniae (MRMp) occurs in the United States or its clinical significance. Between 2015 and 2018, hospitals in 8 states collected and stored respiratory specimens that tested positive for M. pneumoniae and sent them to the University of Alabama at Birmingham, where real-time PCR was performed for detection of 23S rRNA mutations known to confer macrolide resistance. MRMp was detected in 27 of 360 specimens (7.5%). MRMp prevalence was significantly higher in the South and East (18.3%) than in the West (2.1%). A2063G was the predominant 23S rRNA mutation detected. MICs for macrolide-susceptible M. pneumoniae (MSMp) were ≤0.008 μg/ml, whereas MICs for MRMp were 16 to 32 μg/ml. Patients with MRMp infection were more likely to have a history of immunodeficiency or malignancy. Otherwise, there were no other significant differences in the clinical features between patients infected with MRMp and those infected with MSMp, nor were there any differences in radiographic findings, hospitalization rates, viral coinfections, the mean duration of antimicrobial treatment, or clinical outcomes. There was no significant change in MRMp incidence over time or according to age, sex, race/ethnicity, or status as an inpatient or an outpatient. Patients with MRMp were more likely to have received a macrolide prior to presentation, and their treatment was more likely to have been changed to a fluoroquinolone after presentation. This is the first national surveillance program for M. pneumoniae in the United States. Additional surveillance is needed to assess the clinical significance of MRMp and to monitor changes in MRMp prevalence.

[Clinical features and treatment of macrolide-resistant Mycoplasma pneumoniae pneumonia in children]

OBJECTIVE

To study the clinical features of macrolide-resistant Mycoplasma pneumoniae pneumonia and its treatment regimens in children.

METHODS

The samples of throat swab or bronchoalveolar lavage fluid were collected from 136 children with Mycoplasma pneumoniae pneumonia. Quantitative real-time PCR was used to detect 2063/2064 A:G mutation in 23S rRNA, and according to such results, the children were divided into drug-resistance group with 81 children and sensitive group with 55 children. The two groups were compared in terms of age composition, respiratory symptoms, extrapulmonary complications, laboratory markers, imaging changes, treatment regimens, and length of hospital stay.

RESULTS

Compared with the sensitive group, the drug-resistance group had significantly longer duration of pyrexia and severe fever, a significantly higher percentage of children with reduced blood oxygen saturation, and significantly higher levels of alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) (P<0.05). The conventional azithromycin treatment had a good clinical effect in the sensitive group, while corticosteroid therapy was usually needed in the drug-resistance group.

CONCLUSIONS

Macrolide-resistant Mycoplasma pneumoniae infection cannot be identified based on a single clinical feature, but prolonged duration of pyrexia and severe fever, reduced blood oxygen saturation, and increased ALT and LDH can suggest the presence of this disease. Azithromycin combined with glucocorticoids may be a good treatment regimen for children with macrolide-resistant Mycoplasma pneumoniae pneumonia.

[Clinical characteristics of refractory Mycoplasma pneumoniae pneumonia in children]

OBJECTIVE

To provide a basis for early diagnosis and treatment of refractory Mycoplasma pneumoniae pneumonia (RMPP) in children by comparing the clinical characteristics of RMPP and general Mycoplasma pneumoniae pneumonia (MPP).

METHODS

Children with MPP hospitalized between October 2015 and December 2016 were selected as study subjects. According to the diagnostic criteria, children were divided into RMPP group (n=152) and MPP group (n=551). The differences between the two groups in the basic situation, clinical manifestations, infection parameters and myocardial enzymes were compared.

RESULTS

There were no significant differences in gender and age between the RMPP and MPP groups (P>0.05). The peak temperature in the RMPP group was significantly higher than that in the MPP group on the first day of admission (P<0.01). The percentage of children with augmentation in the RMPP group was lower than that in the MPP group (P=0.009). The percentage of neutrophils [Ne(%)] and serum procalcitonin (PCT) levels in the RMPP group were both higher than those in the MPP group (P<0.05), while the percentage of lymphocytes was significantly lower in the RMPP group (P<0.05). The serum levels of aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) in the RMPP group were also higher than those in the MPP group (P<0.05). Binary logistic regression analysis showed that the peak temperature and LDH were closely related to RMPP in children (P<0.05). Receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) of the peak temperature and LDH for the diagnosis of RMPP was 0.647 and 0.637 respectively. In children ≤2 years old, when the threshold value of LDH was 400 U/L, the diagnostic sensitivity was 52.63% and the specificity was 54.84%. In children above 2 years old, when the threshold value of LDH was 335 U/L, the diagnostic sensitivity was 69.92% and the specificity was 51.55%.

CONCLUSIONS

The children with RMPP have a high fever in the early stage. Meanwhile there are abnormal laboratory test results in these children. Elevated serum LDH levels have a high clinical value of early diagnosis of RMPP, especially in children above 2 years.

Mycoplasma pneumoniae 23S rRNA A2063G mutation does not influence chest radiography features in children with pneumonia

Objective

To measure the rate of the A2063G mutation in the Mycoplasma pneumoniae (M. pneumoniae) 23S rRNA domain V in children with pneumonia and to determine the correlation between radiographic findings and the presence of the A2063G mutation.

Methods

Patients who were hospitalized with a confirmed diagnosis of M. pneumoniae pneumonia were enrolled in this study. M. pneumoniae strains were collected for genotype analysis. Chest radiography was performed on all children prior to and following macrolide treatment. Clinical and imaging data were obtained.

Results

Of 211 patients, 195 (92.42%) harboured M. pneumoniae with the A2063G mutation. No significant differences were identified in inflammation score, chest radiography inflammation absorption grade before and after macrolide treatment, or pulmonary complications (atelectasis, hydrothorax, or pleuritis) prior to macrolide treatment when children were stratified based on the presence or absence of the A2063G mutation.

Conclusions

A high proportion of children with pneumonia harboured strains of M. pneumoniae with the A2063G mutation in the 23S rRNA domain V. However, no obvious chest radiographic features of M. pneumoniae pneumonia were associated with the A2063G variant.

Mycoplasma pneumoniae from the Respiratory Tract and Beyond

Mycoplasma pneumoniae is an important cause of respiratory tract infections in children as well as adults that can range in severity from mild to life-threatening. Over the past several years there has been much new information published concerning infections caused by this organism. New molecular-based tests for M. pneumoniae detection are now commercially available in the United States, and advances in molecular typing systems have enhanced understanding of the epidemiology of infections. More strains have had their entire genome sequences published, providing additional insights into pathogenic mechanisms. Clinically significant acquired macrolide resistance has emerged worldwide and is now complicating treatment. In vitro susceptibility testing methods have been standardized, and several new drugs that may be effective against this organism are undergoing development. This review focuses on the many new developments that have occurred over the past several years that enhance our understanding of this microbe, which is among the smallest bacterial pathogens but one of great clinical importance.

Therapeutic efficacy of azithromycin, clarithromycin, minocycline and tosufloxacin against macrolide-resistant and macrolide-sensitive Mycoplasma pneumoniae pneumonia in pediatric patients

OBJECTIVE

To clarify therapeutic effects of azithromycin, clarithromycin, minocycline and tosufloxacin against macrolide-resistant Mycoplasma pneumoniae (MRMP) pneumonia and against macrolide-sensitive Mycoplasma pneumoniae (MSMP) pneumonia in pediatric patients.

METHODS

A prospective, multicenter observational study was conducted from July 2013 to August 2015. The therapeutic effects of azithromycin, clarithromycin, minocycline and tosufloxacin were evaluated in 59 patients with pneumonia caused by MRMP and in 50 patients with pneumonia caused by MSMP. In vitro activities of antimicrobial agents against isolates of Mycoplasma pneumoniae were also measured.

RESULTS

Mean durations of fever following commencement of treatment in patients infected with MRMP and MSMP were 5.2 and 1.9 days, respectively (log-rank test, P < 0.0001). Among patients infected with MRMP, mean durations of fever were 4.6, 5.5, 1.0 and 7.5 days for patients treated with azithromycin, clarithromycin, minocycline and tosufloxacin, respectively (log-rank test, P < 0.0001). Among patients infected with MSMP, mean durations of fever were 2.5, 1.7, 0.9 and 4.3 days for patients treated with azithromycin, clarithromycin, minocycline and tosufloxacin, respectively (log-rank test, P = 0.0162). The MIC90s of azithromycin and clarithromycin among the 27 isolates of MRMP were 64 and 256 μg/ml, respectively, and those among the 23 isolates of MSMP were <0.000125 and 0.001 μg/ml, respectively. The MIC90s of minocycline and tosufloxacin among the 27 isolates of MRMP were 1.0 and 0.25 μg/ml, respectively, and those among the 23 isolates of MSMP were 1.0 and 0.5 μg/ml, respectively.

CONCLUSION

Both minocycline and tosufloxacin showed good in vitro activities against MRMP. Minocycline, but not tosufloxacin, shortened the duration of fever in pediatric patients infected with MRMP compared to the duration of fever in patients treated with macrolides.

Community-Acquired Pneumonia in the Asia-Pacific Region

Community-acquired pneumonia (CAP) is an important cause of mortality and morbidity worldwide. Aging population, dense urbanization, and poor access to health care make the Asia-Pacific region vulnerable to CAP. The high incidence of CAP poses a significant health and economic burden in this region. Common etiologic agents in other global regions including Streptococcus pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydophila pneumoniae, Staphylococcus aureus, and respiratory viruses are also the most prevalent pathogens in the Asia-Pacific region. But the higher incidence of Klebsiella pneumoniae and the presence of Burkholderia pseudomallei are unique to the region. The high prevalence of antimicrobial resistance in S. pneumoniae and M. pneumoniae has been raising the need for more prudent use of antibiotics. Emergence and spread of community-acquired methicillin-resistant S. aureus deserve attention, while the risk has not reached significant level yet in cases of CAP. Given a clinical and socioeconomic importance of CAP, further effort to better understand the epidemiology and impact of CAP is warranted in the Asia-Pacific region.

Regional Differences in Prevalence of Macrolide Resistance among Pediatric Mycoplasma pneumoniae Infections in Hokkaido, Japan

Recently, macrolide-resistant (MR) Mycoplasma pneumonia appeared, and prevalence of macrolide resistance among M. pneumoniae infections varies by country. However, reports on regional differences in the prevalence of MR M. pneumonia within a country are scarce. In this study, 617 nasopharyngeal swab samples were collected from 617 pediatric patients, and DNA of M. pneumoniae was identified in 95 samples. In 51 of the 95 M. pneumonia positive samples, we detected the presence of mutation A2063G mutation (conferring macrolide resistance) in the 23S rRNA gene. The overall macrolide resistance rate was 53.7%, but there were regional differences: 0.0% in Muroran, 5.3% in Asahikawa, 55.3% in Sapporo, and 100.0% in Kushiro. Statistically significant pairwise differences in the prevalence of MR M. pneumoniae were observed among these cities except for the pair of Muroran and Asahikawa. After exclusion (in order to avoid the influence of macrolides) of patients who were prescribed macrolides before collection of nasopharyngeal swab samples, statistically significant differences persisted: 0.0% in Muroran, 5.6% in Asahikawa, 38.5% in Sapporo, and 100.0% in Kushiro.

Macrolide-resistant Mycoplasma pneumoniae in adults in Zhejiang, China

Mycoplasma pneumoniae is a major pathogen causing community-acquired pneumoniae (CAP), which is generally treated with macrolides. In recent years, however, although macrolide-resistant M. pneumoniae has been reported frequently, particularly in China, very little is known about the prevalence of macrolide-resistant M. pneumoniae infection in adults. In this study, we survey the macrolide-resistant M. pneumoniae in adults in Zhejiang province and characterize the mechanisms of resistance to macrolide. Six hundred fifty throat swab samples were collected from adult patients with CAP from January 2012 to August 2014. These samples were assayed by nested PCR and then cultivated for M. pneumoniae. All isolates were sequenced to determine the mutation in domain V of the 23S rRNA gene. The activities of 10 antibiotics against macrolide-resistant M. pneumoniae isolates were also investigated in vitro. Moreover, restriction fragment length polymorphism (RFLP) analysis of the amplified P1 gene was used to type 50 resistant strains. One hundred percent (71/71) of M. pneumoniae strains isolated from adults with CAP were resistant to erythromycin (MIC=128 to >256 μg/ml), clarithromycin (MIC=128 to >256 μg/ml), and azithromycin (MIC=32 to >64 μg/ml). Furthermore, all macrolide-resistant M. pneumoniae strains identified had an A2063G mutation in domain V of the 23S rRNA gene. Forty-six resistant strains (92.0%) were classified into type I strain on the basis of P1 gene PCR-RFLP analysis. According to these findings, it is suggested that macrolide-resistant M. pneumoniae infection is very prevalence among adults in Zhejiang province. Thus, there is necessary to perform the epidemiological monitoring of macrolide-resistant M. pneumoniae in the future.

Mycoplasma pneumoniae infections--does treatment help?

Mycoplasma pneumoniae is a common cause of respiratory tract infections (RTI's), especially in children. While severe M. pneumoniae infections are generally treated with antibiotics, the diagnosis as well as treatment of these infections should be reconsidered in the light of recent clinical findings. First, M. pneumoniae was found to be carried in the upper respiratory tract of a relatively high percentage of healthy, asymptomatic children. Clearly, this complicates the diagnosis of a suspected M. pneumoniae RTI and, thus, the decision when to initiate treatment. A complication in the treatment of these infections is that data on the efficacy of antibiotic treatment of M. pneumoniae RTI's are sparse and derived exclusively from comparative studies. A recent Cochrane review concluded that there is insufficient evidence about the efficacy of antibiotics for M. pneumoniae lower respiratory tract infections (LRTI) in children. Due to side effects associated with the use of tetracyclines and quinolones in children, only macrolides can be used to treat M. pneumoniae infections in young patients. The general applicability of macrolides, however, is currently threatened by the worldwide increase in macrolide-resistant M. pneumoniae strains. Finally, limited evidence is available that corticosteroids might have an additional benefit in the treatment of M. pneumoniae infections. In this review, the current issues related to the diagnosis and treatment of M. pneumoniae infections will be discussed.