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

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.

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.

Effectiveness and safety of tetracyclines and quinolones in people with Mycoplasma pneumonia: a systematic review and network meta-analysis

Background

The escalating resistance of Mycoplasma pneumoniae to macrolides has become a significant global health concern, particularly in low-income and middle-income countries (LMICs). Although tetracyclines and quinolones have been proposed as alternative therapeutic options, concerns regarding age-specific safety issues and the lack of consensus in recommendations across various national guidelines prevail. Thus, the primary objective of this study is to ascertain the most efficacious interventions for second-line treatment of M. pneumoniae infection while considering the age-specific safety issues associated with these interventions.

Methods

In this systematic review and network meta-analysis we searched PubMed, Embase, CNKI, and WanFang Data, from inception up to November 11th, 2023. Studies of quinolones or tetracyclines for the treatment of people with M. pneumoniae infection were collected and screened by reading published reports, with any type of study included, and no individual patient-level data requested. A systematic review and direct meta-analysis compared the efficacy of tetracyclines and quinolones regarding time to defervescence (TTD) and the rates of fever disappearance within 24 h and 48 h of antibiotic administration, for managing M. pneumoniae infection. Bayesian network meta-analysis (NMA) was employed to indirectly assess the relative effectiveness of different interventions in people with M. pneumoniae infection and the safety profile of medication in paediatric patients. This study is registered with PROSPERO, CRD42023478383.

Findings

The systematic review and direct meta-analysis included a total of 4 articles involving 246 patients, while the NMA encompassed 85 articles involving a substantial cohort of 7095 patients. The NMA measured the effectiveness across all ages and included 7043 patients, with a mean age of 37.80 ± 3.91 years. Of the 85 included studies, 14 (16.5%) were at low risk of bias, 71 (83.5%) were at moderate risk, and no studies were rated as having a high risk of bias. In the direct meta-analysis, no statistically significant differences were found between tetracyclines and quinolones concerning TTD (mean difference: -0.40, 95% CI: -1.43 to 0.63; I2 = 0%), fever disappearance rate within 24 h of antibiotic administration (OR: 0.37, 95% CI: 0.08-1.79; I2 = 58%), and fever disappearance rate within 48 h of antibiotic administration (OR: 1.10, 95% CI: 0.30-3.98; I2 = 59%). However, the comprehensive NMA analysis of clinical response (in 70 studies; n = 6143 patients), shortening of TTD (in 52 studies; n = 4363 patients), shortening length of cough relief or disappearance (in 39 studies; n = 3235 patients), fever disappearance rate at 48 h (in four studies; n = 418 patients) revealed that minocycline exhibited the most favourable outcomes across these various parameters, and the analysis of fever disappearance rate at 24 h (in three studies; n = 145 patients) revealed that levofloxacin may be the most effective, as indicated by the rank probabilities and surface under the cumulative ranking area (SUCRA) value. Moxifloxacin ranked second in clinical response and in shortening the length of cough relief or disappearance, and third in shortening TTD. Notably, when evaluating the occurrence of adverse reactions in paediatric patients (in four studies; n = 239 children), levofloxacin was associated with the highest SUCRA value rankings for the rate of adverse events.

Interpretation

Our findings suggest that tetracyclines and quinolones may be equally effective. Based on the age of participants in the included studies, minocycline may be the most effective intervention for children over eight years of age when all preventive measures are considered, whereas moxifloxacin may benefit people under eight years of age. However, these results should be interpreted with caution, given the limited number of studies and patients included, and the heterogeneity between included studies. Based on a limited number of studies in children, levofloxacin is likely to have one of the highest rates of adverse reactions. The majority of the studies included in the NMA were from the Asian region, and more randomised controlled trials comparing different therapeutic strategies in patients with M. pneumoniae are warranted. This comparative study provides clinical pharmacists and clinicians with important information to enable them to make informed decisions about treatment options, considering drug efficacy and safety.

Funding

The Natural Science Foundation of Fujian Province, China.

Guidelines for the Management of Respiratory Infectious Diseases in Children in Japan 2022

The members of the Japanese Society for Pediatric Infectious Diseases and the Japanese Society of Pediatric Pulmonology have developed Guidelines for the Management of Respiratory Infectious Diseases in Children with the objective of facilitating appropriate diagnosis, treatment and prevention of respiratory infections in children. The first edition was published in 2004 and the fifth edition was published in 2022. The Guideline 2022 consists of 2 parts, clinical questions and commentary, and includes general respiratory infections and specific infections in children with underlying diseases and severe infections. This executive summary outlines the clinical questions in the Guidelines 2022, with reference to the Japanese Medical Information Distribution Service Manual. All recommendations are supported by a systematic search for relevant evidence and are followed by the strength of the recommendation and the quality of the evidence statements.

Clinical Usefulness of Serum Lactate Dehydrogenase Levels in Mycoplasma pneumoniae Pneumonia in Children

OBJECTIVE

To elucidate the clinical usefulness of lactate dehydrogenase (LDH) levels in children with Mycoplasma pneumoniae (MP) pneumonia and identify cut-off levels in various clinical conditions.

METHODS

The study was retrospectively performed in 145 children who were hospitalized with MP pneumonia. Laboratory findings, including LDH levels at admission and clinical features were retrospectively reviewed from patients' electronic medical records.

RESULTS

The mean age of the study population was 5.9 y, and the mean value of LDH was 809.7 U/L. Poor response to treatment for MP pneumonia, respiratory virus coinfection, severe MP pneumonia, development of postinfectious bronchiolitis obliterans (PIBO) after MP pneumonia, pleural effusion, and oxygen need during illness were significantly associated with serum LDH levels. The cutoff levels of LDH for predicting poor response to treatment for MP pneumonia and respiratory virus coinfection were 1058 U/L [area under the curve (AUC), 0.729] and 803 U/L (AUC, 0.682), respectively. Those for pneumonic lesions involving at least one-third of the total lung volume, prediction of PIBO development, and extrapulmonary manifestations were 1098 U/L (AUC, 0.715), 676 U/L (AUC, 0.714), and 859 U/L (AUC, 0.710), respectively. The cutoff levels for pleural effusion during illness and for the prediction of oxygen need were 894 U/L (AUC, 0.699) and 1114 U/L (AUC, 0.771), respectively.

CONCLUSION

LDH levels are elevated in diverse clinical conditions in children with MP pneumonia and may be useful in the identification of severe clinical courses of MP pneumonia in children.

The efficacy and safety of minocycline as adjuvant therapy in refractory mycoplasma pneumonia in Chinese children: a meta-analysis

Background

To explore the efficacy and safety of minocycline as adjuvant therapy for refractory mycoplasma pneumonia in Chinese children.

Methods

PubMed, EMBASE, Cochrane Library, CNKI, Wanfang database and VIP database were systematically searched. Studies where minocycline was used as adjuvant therapy for refractory mycoplasma pneumonia in Chinese children were included. The effect of numeration data and the measurement data were represented by odds ratios (OR) and weighted mean differences (MD), respectively. Review Manager version 5.3 was used to compare the treatment efficacy, time for the cough to subside, defervescence time, hospitalisation time, adverse events and other indicators.

Results

Ten studies involving 857 patients were included in the final analysis. Compared with the conventional treatment of refractory mycoplasma pneumonia in children, the addition of minocycline as adjuvant therapy was found to improve the treatment efficacy (OR: 5.45; 95% CI: 3.46, 8.57, p < 0.001); shorten the duration of cough (MD: -3.61; 95%CI: -4.25, -2.97, p < 0.001), fever time (MD: -4.77; 95% CI: -6.30, -3.23, p < 0.001) and hospitalisation time (MD: -5.53 (95% CI: -7.19, -3.88, p < 0.001); and decrease the concentration of C-reactive protein (MD: -13.95; 95%CI: -18.61, -9.29; p < 0.001) and the erythrocyte sedimentation rate (MD: -10.88; 95% CI: -14.05, -7.72, p < 0.001). The use of minocycline did not lead to significant adverse events (OR = 0.63; 95% CI: 0.39, 1.01, p = 0.05).

Conclusion

The use of minocycline as adjuvant treatment of refractory mycoplasma pneumonia in Chinese children has good efficacy and safety and may be promoted in clinical practice.

Clinical role of M. pneumoniae typing antibody detected by chemiluminescent immunoassay in the diagnosis of Mycoplasma pneumoniae pneumonia in children

OBJECTIVE

The levels of serum M. pneumoniae typing antibodies in children with community-acquired pneumonia (CAP) were detected by chemiluminescent immunoassay (CLIA) to explore the clinical role of M. pneumoniae typing antibody (MP-IgM, MP-IgG) in M. pneumoniae pneumonia.

METHODS

A total of 387 Child patients with CAP diagnosed at the Pediatric outpatient department of Zengcheng Branch, Nanfang Hospital, Southern Medical University, were enrolled between January 2020 to December 2021 and divided into M. pneumoniae pneumonia (MPP) group (n = 210) and non-M. pneumoniae pneumonia (NMPP) group (n = 177). Firstly, Clinical data, full blood count (WBC, NEU%, LYM%, MONO%, EOS%, BASO%, RBC, HGB, PLT) and biochemical tests (AST, LDH, ɑ-HBDH, CK, CKMB, CRP, PCT, IL-6) as well as laboratory diagnostic tests (MP-IgM, MP-IgG) were compared between the two groups. Secondly, we assessed the correlation between the average level of M. pneumoniae typing antibody detected by CLIA and the titer of anti-M. pneumoniae antibody (MP-Ab) tested by passive agglutination (PA) method. Thirdly, receiver operating characteristic (ROC) curve for the MP-IgM and MP-IgG was examined to evaluate the value of diagnosing M. pneumoniae pneumonia. Finally, we follow-up 120 cases of MPP group and analysis medication results.

RESULTS

(1) Mean age, runny nose, expectoration, LYM%, NEU%, HGB, AST, MP-IgM and MP-IgG were statistically significant in the MPP group and NMPP group (all P < 0.05). (2) Correlation analysis showed that MP-IgM average level was linearly associated with MP-Ab titer (R² = 0.84) and MP-IgG average level was exponentially correlated with MP-Ab titer under 1:640 (R² = 0.96). (3) The ROC curve of MP-IgM and MP-IgG were significantly different (both P < 0.001). A serum MP-IgM level above 1 S/CO and MP-IgG level above 14.15 AU/mL were significant predictors for M. pneumoniae pneumonia: area under the curve (AUC) of 0.810, 0.815; standard error (SE) of 0.021, 0.022; 95 % confidence interval (CI) of 0.768-0.852, 0.773-0.858; the diagnostic sensitivity of 74.3 %, 62.1 %; and specificity of 72.9 %, 87.0 %; respectively. (4) Of the 120 children with M. pneumoniae pneumonia followed up, 79 (65.8 %) cases took azithromycin and 68 (86.1 %) cases were recovered.

CONCLUSIONS

A series of our studies shown that, CLIA, speedy and automated clinical examination method, has higher specificity and sensitivity for the quantitative detection of MP-IgM and MP-IgG, playing an important role of early diagnosis as well as prompt intervention to reduces macrolide-resistant strains and sequelae of children with M. pneumoniae pneumonia.

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.

Refractory Mycoplasma pneumoniae Pneumonia in Children: Early Recognition and Management

Refractory Mycoplasma pneumoniae pneumonia (RMPP) is a severe state of M. pneumoniae infection that has attracted increasing universal attention in recent years. The pathogenesis of RMPP remains unknown, but the excessive host immune responses as well as macrolide resistance of M. pneumoniae might play important roles in the development of RMPP. To improve the prognosis of RMPP, it is mandatory to recognize RMPP in the early stages, and the detection of macrolide-resistant MP, clinical unresponsiveness to macrolides and elevated proinflammatory cytokines might be clues. Timely and effective anti-mycoplasmal therapy and immunomodulating therapy are the main strategies for RMPP.

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.

Mycoplasma pneumoniae and Chlamydia pneumoniae Coinfection with Acute Respiratory Distress Syndrome: A Case Report

Community-acquired pneumonia caused by Mycoplasma pneumoniae or Chlamydia pneumoniae is usually mild. Mycoplasma pneumoniae-related and C. pneumoniae-related acute respiratory distress syndromes (ARDSs) are rare. Moreover, to our knowledge, there are no published reports on ARDS caused by M. pneumoniae and C. pneumoniae coinfection. Here, we report a case of an immunocompetent young woman who was co-infected with M. pneumoniae and C. pneumoniae and was started on treatment with piperacillin and clarithromycin. Two days later, she developed ARDS. She recovered rapidly following a change of antibiotic treatment to levofloxacin and was discharged on day 12. We conducted exome sequencing followed by alternative filtering to search for candidate ARDS-related genes. We identified an intronic variant of unknown significance within leucine-rich repeat-containing 16A (LRRC16A), a gene previously identified as a significant locus for platelet count with a possible role in ARDS. This is a rare case of ARDS in a young adult caused by M. pneumoniae and C. pneumoniae coinfection. This case suggests that ARDS in young adults may be correlated with variants in LRRC16A. This requires confirmation by further case reports.

Effects of minocycline on macrolide-unresponsive Mycoplasma pneumoniae pneumonia in children: a single-center retrospective study

BACKGROUND

Macrolide-resistant Mycoplasma pneumoniae (Mp) has become widespread in the world. We sought to determine the independently associated risk factors for refractory Mp pneumonia among macrolide-unresponsive Mp pneumonia children treated with minocycline and to investigate the effects of minocycline against macrolide-unresponsive Mp pneumonia.

METHODS

In our center, we retrospectively analyzed the data of hospitalized macrolide-unresponsive Mp pneumonia patients aged ≤18 years old who changed macrolide therapies to minocycline treatments between March 2013 and September 2018. Patient characteristics and defervescence after minocycline treatment were compared between refractory Mp pneumonia and non-refractory Mp pneumonia groups. Multivariable logistic regression analysis was performed among these macrolide-unresponsive Mp pneumonia patients.

RESULTS

Among 150 included macrolide-unresponsive Mp pneumonia children treated with minocycline; 30 cases (20.0%) were refractory Mp pneumonia. Duration of macrolide treatment before administration of minocycline (odds ratio =2.87, 95% CI: 1.79-4.61, P<0.001) and serum procalcitonin levels (odds ratio =13.50, 95% CI: 1.22-149.57, P=0.034) were independently associated with refractory Mp pneumonia. Defervescence after minocycline treatment was significantly longer among the refractory Mp pneumonia group than in the non-refractory Mp pneumonia group (median 2 vs. 1 day, P<0.001). Only one case (0.7%) suspected of a side effect of minocycline therapy was observed.

CONCLUSIONS

Two risk factors independently associated with refractory Mp pneumonia were determined. Early use of minocycline might safely prevent macrolide-unresponsive Mp pneumonia from progressing to refractory Mp pneumonia.

Point-of-care molecular diagnosis of Mycoplasma pneumoniae including macrolide sensitivity using quenching probe polymerase chain reaction

Objectives

Macrolides are generally considered to be the drugs of choice for treatment of patients with Mycoplasma pneumoniae infection. However, macrolide-resistant M. pneumoniae has been emerging since about 2000. The Smart Gene^® system (MIZUHO MEDY Co., Ltd., Tosu, Japan) is a novel fully automated system for detection of pathogens using the method of quantitative polymerase chain reaction (qPCR) with QProbe (QProbe PCR). The entire procedure is completed within 50 min and the size of the instrument is small (15 x 34 x 30 cm). The purpose of this study was to evaluate the usefulness of the Smart Gene^® system for detection of M. pneumoniae and detection of a point mutation at domain V of the 23S rRNA gene of M. pneumoniae.

Materials

Pharyngeal swab samples were collected from 154 patients who were suspected of having respiratory tract infections associated with M. pneumoniae.

Results

Compared with the results of qPCR, the sensitivity and specificity of the Smart Gene^® system were 98.7% (78/79) and 100.0% (75/75), respectively. A point mutation at domain V of the 23S rRNA gene was detected from 7 (9.0%) of 78 M. pneumoniae-positive samples by the Smart Gene^® system and these results were confirmed by direct sequencing. The minimum inhibitory concentrations of clarithromycin among the 5 isolates of M. pneumoniae with a point mutation at domain V of the 23S rRNA gene were >64 μg/ml and those among the 33 isolates without a mutation in the 23S rRNA gene were <0.0625 μg/ml.

Conclusion

The Smart Gene^® system is a rapid and accurate assay for detection of the existence of M. pneumoniae and a point mutation at domain V of the 23S rRNA gene of M. pneumoniae at the same time. The Smart Gene^® system is suitable for point-of-care testing in both hospital and outpatient settings.

Efficacy of tetracyclines and fluoroquinolones for the treatment of macrolide-refractory Mycoplasma pneumoniae pneumonia in children: a systematic review and meta-analysis

Background

Mycoplasma pneumoniae is a common pathogen that causes community-acquired pneumonia in school-age children. Macrolides are considered a first-line treatment for M. pneumoniae infection in children, but macrolide-refractory M. pneumoniae (MRMP) strains have become more common. In this study, we assessed the efficacy of tetracyclines and fluoroquinolones in MRMP treatment in children through a systematic review and meta-analysis.

Methods

Two reviewers individually searched 10 electronic databases (Medline/Pubmed, Embase, the Cochrane Library, and core Korean, Chinese, and Japanese journals) for papers published from January 1, 1990 to March 8, 2018. The following data for each treatment group were extracted from the selected studies: intervention (tetracyclines and fluoroquinolones/comparator), patient characteristics (age and sex), and outcomes (fever duration, hospital stay length, treatment success rate, and defervescence rates 24, 48, and 72 h after starting treatment).

Results

Eight studies involving 537 participants were included. Fever duration and hospital stay length were shorter in the tetracycline group than in the macrolide group (weighted mean difference [WMD] = − 1.45, 95% confidence interval [CI]: − 2.55 to − 0.36, P = 0.009; and WMD = − 3.33, 95% CI: − 4.32 to − 2.35, P < 0.00001, respectively). The therapeutic efficacy was significantly higher in the tetracycline group than in the macrolide group (odds ratio [OR]: 8.80, 95% CI: 3.12–24.82). With regard to defervescence rate, patients in the tetracycline group showed significant improvement compared to those in the macrolide group (defervescence rate after 24 h, OR: 5.34, 95% CI: 1.81–15.75; after 48 h, OR 18.37, 95% CI: 8.87–38.03; and after 72 h, OR: 40.77, 95% CI: 6.15–270.12). There were no differences in fever improvement within 24 h in patients in the fluoroquinolone group compared to those in the macrolide group (OR: 1.11, 95% CI: 0.25–5.00), although the defervescence rate was higher after 48 h in the fluoroquinolone group (OR: 2.78, 95% CI: 1.41–5.51).

Conclusion

Tetracyclines may shorten fever duration and hospital stay length in patients with MRMP infection. Fluoroquinolones may achieve defervescence within 48 h in patients with MRMP infection. However, these results should be carefully interpreted as only a small number of studies were included, and they were heterogeneous.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06508-7.

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.

P1 gene of Mycoplasma pneumoniae isolated from 2016 to 2019 and relationship between genotyping and macrolide resistance in Hokkaido, Japan

We characterized 515 Mycoplasma pneumoniae specimens in Hokkaido. In 2013 and 2014, the p1 gene type 1 strain, mostly macrolide-resistant, was dominant and the prevalence of macrolide resistance was over 50 %. After 2017, the p1 gene type 2 lineage, mostly macrolide-sensitive, increased and the prevalence of macrolide resistance became 31.0 % in 2017, 5.3 % in 2018 and 16.3 % in 2019.

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.

Clinical Evaluation of a Novel Point-of-Care Assay To Detect Mycoplasma pneumoniae and Associated Macrolide-Resistant Mutations

The recent increase in macrolide-resistant Mycoplasma pneumoniae in Asia has become a continuing problem. A point-of-care testing method that can quickly detect M. pneumoniae and macrolide-resistant mutations (MR mutations) is critical for proper antimicrobial use. Smart Gene (Mizuho Medy Co., Ltd., Tosu City, Saga, Japan) is a compact and inexpensive fully automatic gene analyzer that combines amplification with PCR and the quenching probe method to specify the gene and MR mutations simultaneously. We performed a clinical evaluation of this device and its reagents on pediatric patients with suspected M. pneumoniae respiratory infections and evaluated the impact of the assay on antimicrobial selection. Using real-time PCR as a comparison control, the sensitivity of Smart Gene was 97.8% (44/45), its specificity was 93.3% (98/105), and its overall concordance rate was 94.7% (142/150). The overall concordance rate of Smart Gene diagnosis of MR mutations in comparison with sequence analysis was 100% (48/48). The ratio of MR mutations was significantly higher at high-level medical institutions than at a primary medical clinic (P = 0.023), and changes in antibiotic therapy to drugs other than macrolides were significantly more common in patients with MR mutations (P = 0.00024). Smart Gene demonstrated excellent utility in the diagnosis of M. pneumoniae and the selection of appropriate antimicrobials for MR mutations at primary medical institutions, which play a central role in community-acquired pneumonia care. The use of this device may reduce referrals to high-level medical institutions for respiratory infections, thereby reducing the medical and economic burdens on patients.

Mutations in domain V of Mycoplasma pneumoniae 23S rRNA and clinical characteristics of pediatric M. pneumoniae pneumonia in Nanjing, China

OBJECTIVE

To investigate the prevalence of mutations in domain V of Mycoplasma pneumoniae (MP) 23S ribosomal RNA (rRNA) and the clinical characteristics of pediatric MP pneumonia (MPP) in Nanjing, China.

METHODS

Domain V of 23S rRNA was sequenced in MP strains collected from children diagnosed with MPP in Nanjing. Clinical and laboratory data were obtained.

RESULTS

Among the 276 MP strains, 255 (92.39%) harbored mutations, primarily A2063G in domain V of MP 23S rRNA. When children were stratified according to the presence or absence of mutations, no significant differences were found in sex, age, the MP DNA load at enrollment, lymphocyte counts, pulmonary complications, immunomodulator levels, fever duration, the duration of fever after macrolide therapy, and hospital stay. The prevalence of refractory MPP in the two groups was similar. Children with refractory MPP exhibited higher MP DNA loads than those with non-refractory MPP.

CONCLUSIONS

Despite the high prevalence of the A2063G mutation in domain V of MP 23S rRNA, mutations were not associated with the clinical characteristics of MPP. The MP DNA load significantly differed between refractory and non-refractory MPP.

Evaluation of a novel immunochromatographic assay using silver amplification technology for detection of Mycoplasma pneumoniae from throat swab samples in pediatric patients

Objectives

Mycoplasma pneumoniae is one of the common causative pathogens of community-acquired respiratory tract infections mainly in children and young adults. Rapid and accurate diagnostic techniques for identifying the causative pathogen would be useful for initiating treatment with an appropriate antibiotic. The purpose of the present study was to evaluate the sensitivity and specificity of a novel immunochromatographic assay using silver amplification technology using FUJI DRI-CHEM IMMUNO AG2 and FUJI DRI-CHEM IMMUNO AG cartridge Myco (FUJIFILM Co., Tokyo, Japan) for detection of M. pneumoniae.

Methods

Throat swab samples were collected from 170 pediatric patients who were diagnosed with bronchitis or pneumonia. The silver amplification immunochromatographic (SAI) assay was performed using these samples and the results were compared with those of real-time PCR. The time required for the SAI assay is approximately 20 min (5 min for sample preparation and 15 min for waiting time after starting the assay).

Results

The sensitivity and specificity of the SAI assay for detection of M. pneumoniae were 85.2 and 99.1%, respectively, and the assay showed positive and negative predictive values of 98.1 and 92.3%, respectively, compared with the results of real-time PCR. The diagnostic accuracy was 94.1%.

Conclusions

FUJI DRI-CHEM IMMUNO AG2 and FUJI DRI-CHEM IMMUNO AG cartridge Myco are appropriate for clinical use. The optimal timing of this assay is five days or more after the onset of M. pneumoniae infection. However, PCR or other molecular methods are superior, especially with regard to sensitivity and negative predictive value.

A comparison of efficacy and safety of complementary and alternative therapies for severe mycoplasma pneumonia in children: A protocol for systematic review and meta-analysis

BACKGROUND

In recent years, the incidence rate of children with severe Mycoplasma pneumoniae pneumonia (SMPP) is increasing, which poses a great threat to children's life and safety. There are some limitations in the existing drugs for the treatment of SMPP, and the supplementary and alternative therapy of SMPP plays an irreplaceable role in the treatment of this disease. This study will evaluate the efficacy and safety of various complementary and alternative therapies for SMPP by means of mesh meta-analysis. In order to provide the basis for clinical rational use.

METHODS

Two researchers will independently and comprehensively searched the Cochrane Central controlled trials registry, Cochrane Library, PubMed, web of science, EMBASE, CNKI, and Wanfang database to collect randomized controlled trials (RCT) studies on complementary and alternative therapies for SMPP. And the relevant references included in the systematic review/meta-analysis are screened. The retrieval time limit is from the establishment of the database to November 2020. We will use Revman 5.3 software for meta-analysis and use grade to grade the quality of evidence in the net meta-analysis (NMA).

RESULTS

The aim of this study was to compare the efficacy and safety of different complementary and alternative therapies in the treatment of SMPP, with a view to evaluating and ranking different interventions.

CONCLUSION

The supplement and replacement therapy of SMPP can improve the clinical efficacy, relieve the clinical symptoms, improve the quality of life of children, and reduce adverse reactions, which can provide strong support for the rational use of clinicians.

INPLASY REGISTRATION NUMBER

INPLASY2020110079.

Clinical Efficacy of Doxycycline for Treatment of Macrolide-Resistant Mycoplasma pneumoniae Pneumonia in Children

In areas with high prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) pneumonia, treatment in children has become challenging. This study aimed to analyze the efficacy of macrolides and doxycycline with regard to the presence of macrolide resistance. We analyzed children with MP pneumonia during the two recent epidemics of 2014–2015 and 2019–2020 from four hospitals in Korea. Nasopharyngeal samples were obtained from children with pneumonia for MP cultures and polymerase chain reaction (PCR). Macrolide resistance was determined by the analysis of 23S rRNA gene transition. Time to defervescence and to chest X-ray improvement were analyzed. Of 145 cases, the median age was 5.0 years and MRMP accounted for 59 (40.7%). Among macrolide-susceptible MP (MSMP), 78 (90.7%) were treated with macrolides and 21 (35.6%) in the MRMP group with doxycycline. In MRMP pneumonia, shorter days to defervescence (2 vs. 5 days, p < 0.001) and to chest X-ray improvement (3 vs. 6 days, p < 0.001) in the doxycycline group than in the macrolide group was observed, whereas no differences were observed among children with MSMP pneumonia. Compared to macrolides, treatment with doxycycline resulted in better outcomes with a shorter time to defervescence and to chest X-ray improvement among children with MRMP pneumonia.

Clinical characteristics of refractory mycoplasma pneumoniae pneumonia in children treated with glucocorticoid pulse therapy

BACKGROUND

To observe the effect of corticosteroids in the treatment of children with refractory Mycoplasma pneumoniae pneumonia (RMPP) under different doses, to summarize the clinical features of children treated with glucocorticoid pulse therapy.

METHODS

The clinical data of 125 children with RMPP hospitalized in Tianjin Children's Hospital from September 2018 to October 2019 were retrospectively analyzed. They were divided into two groups according to the dose of hormone. Compare the clinical features, laboratory findings, and imaging between the two groups, and use meaningful related indicators as ROC curves to find reference indicators for pulse therapy.

RESULTS

(1) The median age of the group II was older than that of the group I(P < 0.05). (2) We found more severe presentations, higher incidence of extra-pulmonary complications and more serious radiological findings in group II, which needed oxygen more often, higher the hormone, higher usage rate of gamma globulin, higher usage rate of bronchoscopy, and higher incidence of plastic bronchitis(P < 0.05). (3) WBC, CRP, LDH, FER, D-D dimer, APTT, TT, PCT, IL-6 and the percentage of neutrophils in peripheral blood in Group II were higher than those in Group I(P < 0.05). (4) In ROC curve analysis, CRP, LDH, FER, and neutrophils of leukocyte classification were independent related factors that could be used as valuable predictors of methylprednisolone pulse therapy for RMPP in children. The cut-off values were CRP44.45 mg/L, LDH590IU/L, FER411ng/L, and neutrophils in leukocyte classification were 73.75%, respectively.

CONCLUSION

CRP ≥ 44.45 mg/L, LDH ≥ 590 IU/L, FER ≥ 411 ng/L, neutrophil≥73.75%, lung consolidation, and pleural effusion may be predictors that guide the treatment of RMPP with pulse dose of GC.

Emergent Pneumonia in Children

In recent decades there have been multiple pathogens, viruses and bacteria, which have emerged as causal agents of pneumonia affecting adults, albeit less frequently, to children. For the purposes of this article we have classified emerging pathogens as follows: True emerging, to pathogens identified for the very first time affecting human population (SARS-CoV-1, SARS-CoV-2, MERS-CoV, avian influenza, and hantavirus); Re-emerging, to known pathogens which circulation was controlled once, but they have reappeared (measles, tuberculosis, antimicrobial resistant bacteria such as CA-MRSA, Mycoplasma pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and new serotypes of post-vaccine pneumococcal); and finally, those that we have called old known with new presentations, including common pathogens that, in particular condition, have changed their form of presentation (rhinovirus, and non-SARS coronavirus). We will review for each of them their epidemiology, forms of presentation, therapy, and prognosis in children compared to the adult with the aim of being able to recognize them to establish appropriate therapy, prognostics, and effective control measures.

Risk factors for the development of post-infectious bronchiolitis obliterans after Mycoplasma pneumoniae pneumonia in the era of increasing macrolide resistance

BACKGROUND

The prevalence of macrolide-resistant Mycoplasma pneumoniae (MP) pneumonia has been rapidly increased. MP pneumonia is a risk factor for the development of post-infectious bronchiolitis obliterans (PIBO). The aim of the present study was to identify the risk factors for the development of PIBO after MP pneumonia in the era of increasing macrolide resistance of MP.

MATERIALS AND METHODS

This retrospective study enrolled 150 children with a mean age of 6.0 years admitted to the hospital due to MP pneumonia between May 2019 and February 2020 at a tertiary hospital. The clinical, radiologic, and laboratory data were obtained using retrospective chart review.

RESULTS

Eighteen children (12%) were diagnosed with PIBO after MP pneumonia. PIBO was diagnosed after a mean duration of 100.0 days (range, 6-268 days) from symptom onset. The respiratory virus co-infection (adjusted odds ratio [aOR], 4.069; 95% confidence interval [95% CI], 1.224-13.523), adenovirus co-infection (aOR, 5.607; 95% CI, 1.801-17.454), longer duration between symptom onset and admission (aOR, 1.150; 95% CI, 1.020-1.298), higher levels of serum lactate dehydrogenase (LDH) at the time of admission (aOR, 1.001; 95% CI, 1.000-1.003), and poor response to stepwise treatment increased the risk for development of PIBO after MP pneumonia. However, macrolide resistance of MP was not associated with development of PIBO after MP pneumonia.

CONCLUSION

The present study suggests that respiratory virus co-infection, including adenovirus, poor response to the treatment of MP pneumonia, and higher levels of serum LDH, but not macrolide resistance of MP, are risk factors of PIBO after MP pneumonia.

Severe Mycoplasma pneumoniae pneumonia requiring intensive care in children, 2010-2019

BACKGROUND/PURPOSE

Despite the high prevalence of Mycoplasma pneumoniae infections, reports on severe life-threatening M. pneumoniae pneumonia (MPP) in children are limited.

METHODS

We retrospectively enrolled pediatric patients with PCR-positive MPP requiring ICU admission in a children's hospital in Taipei, Taiwan from Jun 2010 to October 2019. Clinical manifestations and laboratory data of severe MPP were analyzed. Macrolide susceptibility was determined by genotyping, and its relationship with clinical manifestations was also analyzed.

RESULTS

Approximately 5% (34/658) children hospitalized for MPP required ICU admission. Compared with non-ICU cases (n = 291), ICU cases (n = 34) were associated with more underlying conditions, more pleural effusion, longer fever duration, longer hospital stay, the requirement of second-line antibiotic treatment, and delayed effective and second-line antibiotic treatment. Macrolide resistance was similar in ICU and non-ICU groups (53% vs 53%; p = 0.986). In severe MPP, patients requiring endotracheal intubation were associated with more septic shock, empyema, ARDS, prolonged fever after effective antibiotic treatment, delayed second-line and effective antibiotic treatment. In 18 of the 22 patients with pleural fluid analysis, the pleural effusion was alkaline (pH > 7.7) and lymphocyte-predominant.

CONCLUSION

M. pneumoniae infection can cause severe life-threatening pneumonia in children. Delayed effective and second-line antibiotic treatments are associated with severe life-threatening MPP.

Impact of viral coinfection and macrolide-resistant mycoplasma infection in children with refractory Mycoplasma pneumoniae pneumonia

Background

Cases of refractory Mycoplasma pneumoniae pneumonia have been increasing recently; however, whether viral coinfection or macrolide-resistant M. infection contribute to the development of refractory M. pneumoniae pneumonia remains unclear. This study aimed to investigate the impacts of viral coinfection and macrolide-resistant M. pneumoniae infection on M. pneumoniae pneumonia in hospitalized children and build a model to predict a severe disease course.

Methods

Nasopharyngeal swabs or sputum specimens were collected from patients with community-acquired pneumonia meeting our protocol who were admitted to Shanghai Children’s Medical Center from December 1, 2016, to May 31, 2019. The specimens were tested with the FilmArray Respiratory Panel, a multiplex polymerase chain reaction assay that detects 16 viruses, Bordetella pertussis, M. pneumoniae, and Chlamydophila pneumoniae. Univariate and multivariate logistic regression models were used to identify the risk factors for adenovirus coinfection and macrolide-resistant mycoplasma infection.

Results

Among the 107 M. pneumoniae pneumonia patients, the coinfection rate was 56.07%, and 60 (60/107, 56.07%) patients were infected by drug-resistant M. pneumoniae. Adenovirus was the most prevalent coinfecting organism, accounting for 22.43% (24/107). The classification tree confirmed that viral coinfection was more common in patients younger than 3 years old. Adenovirus coinfection and drug-resistant M. pneumoniae infection occurred more commonly in patients with refractory M. pneumoniae pneumonia (P = 0.019; P = 0.001). A prediction model including wheezing, lung consolidation and extrapulmonary complications was used to predict adenovirus coinfection. The area under the receiver operating characteristic curve of the prediction model was 0.795 (95% CI 0.679–0.893, P < 0.001). A prolonged fever duration after the application of macrolides for 48 h was found more commonly in patients infected by drug-resistant M. pneumoniae (P = 0.002). A fever duration longer than 7 days was an independent risk factor for drug-resistant Mycoplasma infection (OR = 3.500, 95% CI = 1.310–9.353, P = 0.012).

Conclusions

The occurrence of refractory M. pneumoniae pneumonia is associated with adenovirus coinfection and infection by drug-resistant M. pneumoniae. A prediction model combining wheezing, extrapulmonary complications and lung consolidation can be used to predict adenovirus coinfection in children with M. pneumoniae pneumonia. A prolonged fever duration indicates drug-resistant M. pneumoniae infection, and a reasonable change in antibiotics is necessary.

Concomitant infection with COVID-19 and Mycoplasma pneumoniae

In late 2019, cases of atypical pneumonia caused by a novel coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were first reported in Wuhan, China. The disease was officially called coronavirus disease 2019 (COVID-19) and has been declared a pandemic disease by the World Health Organization (WHO). The clinical symptoms may include fever, cough, fatigue, headache, and diarrhea. The radiographic features comprise various presentations, including ground-glass opacities, tiny nodules, and consolidation. However, some atypical pathogens related to community-acquired pneumonia (CAP) may share similar presentations. They may be difficult to distinguish according to the clinical presentation and radiographic findings. Recently, there have been several reports reminding physicians to heed the possibility of co-infection with other pathogens in patients diagnosed with COVID-19. We report a COVID-19 patient co-infected with Mycoplasma pneumoniae who recovered well after combination therapy. We propose that all COVID-19 patients should undergo a meticulous screening routine to ensure that they receive adequate treatments.

Antibiotic-Resistant Community-Acquired Bacterial Pneumonia

Antimicrobial resistance is a global concern, and prudent use of antibiotics is essential to preserve the current armamentarium of effective drugs. Acute respiratory tract infection is the most common reason for antibiotic prescription in adults. In particular, community-acquired pneumonia poses a significant health challenge and economic burden globally, especially in the current landscape of a dense and aging population. By updating the knowledge on the common antimicrobial-resistant pathogens in community-acquired respiratory tract infections, their prevalence, and resistance may pave the way to enhancing appropriate antibiotic use in the ambulatory and health care setting.

Immunochromatography for the diagnosis of Mycoplasma pneumoniae infection: A systematic review and meta-analysis

The aim of this study was to evaluate the diagnostic performance of immunochromatographic tests (ICTs) for the detection of Mycoplasma pneumoniae. Medline/Pubmed, Embase, the Cochrane Library, and ISI Web of Science were searched through June 12, 2019 for relevant studies that used ICTs for the detection of M. pneumoniae infection with polymerase chain reaction (PCR) or microbial culturing as reference standards. Pooled diagnostic accuracy with 95% confidence interval (CI) was calculated using a bivariate random effects model. We also constructed summary receiver operating characteristic curves and calculated the area under the curve (AUC). Statistical heterogeneity was evaluated by χ² test or Cochrane’s Q test. Thirteen studies including 2,235 samples were included in the meta-analysis. The pooled sensitivity and specificity for diagnosing M. pneumoniae infection were 0.70 (95% CI: 0.59–0.79) and 0.92 (95% CI: 0.87–0.95), respectively. The positive likelihood ratio (LR) was 8.94 (95% CI: 4.90–14.80), negative LR 0.33 (95% CI: 0.22–0.46), diagnostic odds ratio 29.20 (95% CI: 10.70–64.20), and AUC 0.904. In subgroup analysis, ICTs demonstrated similar pooled sensitivities and specificities in populations of children only and mixed populations (children + adults). Specimens obtained from oropharyngeal swabs exhibited a higher sensitivity and specificity than those of nasopharyngeal swab. Moreover, pooled estimates of sensitivity and accuracy for studies using PCR as a reference standard were higher than those using culture. The pooled sensitivity and specificity of Ribotest Mycoplasma^®, the commercial kit most commonly used in the included studies, were 0.66 and 0.89, respectively. Overall, ICT is a rapid user-friendly method for diagnosing M. pneumoniae infection with moderate sensitivity, high specificity, and high accuracy. This suggests that ICT may be useful in the diagnostic workup of M. pneumoniae infection; however, additional studies are needed for evaluating the potential impact of ICT in clinical practice.

Minocycline, focus on mechanisms of resistance, antibacterial activity, and clinical effectiveness: Back to the future

OBJECTIVES

The increasing crisis regarding multidrug-resistant (MDR) and extensively drug-resistant microorganisms leads to appealing therapeutic options.

METHODS

During the last 30 years, minocycline, a wide-spectrum antimicrobial agent, has been effective against MDR Gram-positive and Gram-negative bacterial infections. As with other tetracyclines, the mechanism of action of minocycline involves attaching to the bacterial 30S ribosomal subunit and preventing protein synthesis.

RESULTS

This antimicrobial agent has been approved for the treatment of acne vulgaris, some sexually transmitted diseases and rheumatoid arthritis. Although many reports have been published, there remains limited information regarding the prevalence, mechanism of resistance and clinical effectiveness of minocycline.

CONCLUSION

Thus, we summarize here the currently available data concerning pharmacokinetics and pharmacodynamics, mechanism of action and resistance, antibacterial activity and clinical effectiveness of minocycline.

Clonal Expansion of Macrolide-Resistant Sequence Type 3 Mycoplasma pneumoniae, South Korea

To investigate the genetic background for the emergence of macrolide resistance, we characterized the genetic features of Mycoplasma pneumoniae using multilocus sequence typing. Of the 146 M. pneumoniae strains collected during the 5 consecutive outbreaks of M. pneumoniae pneumonia during 2000–2016 in South Korea, macrolide resistance increased from 0% in the first outbreak to 84.4% in the fifth. Among the 8 sequence types (STs) identified, ST3 (74.7%) was the most prevalent, followed by ST14 (15.1%). Macrolide-susceptible strains comprised 8 different STs, and all macrolide-resistant strains were ST3 (98.3%) except 1 with ST14. The proportion of macrolide-resistant strains in ST3 remained 2.2% (1/46) until the 2006–2007 outbreak and then markedly increased to 82.6% (19/23) during the 2010–2012 outbreak and 95.0% (38/40) during the 2014–2016 outbreak. The findings demonstrated that clonal expansion of ST3 M. pneumoniae was associated with the increase in macrolide resistance in South Korea.

An adult case of severe life-threatening Mycoplasma pneumoniae pneumonia due to a macrolide-resistant strain, Japan: a case report

Background

Until now, the prevalence of macrolide-resistant Mycoplasma pneumoniae (MP) infection among adult patients has been low, and severe MP pneumonia due to a macrolide-resistant strain has seldom been reported. Here, we describe a rare case of severe life-threatening MP pneumonia due to a macrolide-resistant strain in an adult, which was finally treated with fluoroquinolone and tetracycline after failed treatment with macrolide and corticosteroid.

Case presentation

A 39-year-old apparently healthy woman complained of fever and productive cough. Three days after onset, she was admitted to a local general hospital. On admission, her vital signs were stable except for high-grade fever. The patient’s chest X-ray and chest computed tomography images revealed subsegmental consolidation in her right lower lobe. Treatment with ampicillin/sulbactam, and azithromycin were initiated under a clinical diagnosis of community-acquired pneumonia. After treatment initiation, her fever had not subsided, and the pulmonary lesion had extended to the entire lower lobe. Thus, treatment with prednisolone as steroid pulse therapy was initiated from clinical day 7. However, neither her symptoms nor her pulmonary lesion improved; therefore, she was transferred to our hospital for further examination and treatment. On admission (clinical day 14), her indirect hemagglutination titer for MP was elevated at 1:2560, and bronchoalveolar fluid examination yielded positive results for the mycoplasma antigen. Based on these clinical findings, we confirmed a case of severe life-threatening MP pneumonia. Since her respiratory condition was extremely severe, we initiated levofloxacin and tetracycline. Two days later (clinical day 16), her fever, malaise, and hypoxia resolved, and her pulmonary lesions had significantly improved.

Further molecular identification yielded the DNA of MP from her bronchoalveolar fluid, and mutation of A2063G in the 23S rRNA gene was revealed. Based on these results and the clinical course, we confirmed our case as severe MP pneumonia due to a macrolide-resistant strain.

Conclusion

More awareness is needed on the emergence of macrolide-resistant MP infection in adults, because severe infection could develop despite initial treatment with macrolide and steroid therapy, which are generally considered as standard therapy for MP.

Genetic characterization of Mycoplasma pneumoniae isolated in Osaka between 2011 and 2017: Decreased detection rate of macrolide-resistance and increase of p1 gene type 2 lineage strains

We characterized 419 Mycoplasma pneumoniae isolates collected between 2011 and 2017 in Osaka prefecture of Japan. This analysis revealed high prevalence of macrolide-resistant M. pneumoniae (MRMP) in Osaka during 2011 and 2014 with annual detection rates of MRMP strains between 71.4% and 81.8%. However, in 2015 and after, the detection rate of MRMP decreased significantly and did not exceed 50%. Genotyping of the p1 gene of these isolates showed that most of MRMP strains harbored type 1 p1 gene. In contrast, strains expressing p1 gene type 2 or its variant were largely macrolide-susceptible M. pneumoniae (MSMP) strains. There was a strong correlation between p1 gene genotype and the presence of mutations conferring macrolide resistance in M. pneumoniae isolated in Osaka. These results indicate that lower incidence of MRMP strains in Osaka from 2015 was associated with the relative increase of p1 gene type 2 lineage strains. During these experiments, we also isolated three M. pneumoniae strains that showed irregular typing pattern in the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the p1 gene. Two of these strains harbored new variants of type 2 p1 gene and were designated as type 2f and 2g. The remaining strain with an irregular typing pattern had a large deletion in the p1 operon.

Therapeutic Efficacy and Safety of Prolonged Macrolide, Corticosteroid, Doxycycline, and Levofloxacin against Macrolide-Unresponsive Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND

We aimed to compare the therapeutic efficacy of prolonged macrolide (PMC), corticosteroids (CST), doxycycline (DXC), and levofloxacin (LFX) against macrolide-unresponsive Mycoplasma pneumoniae (MP) pneumonia in children and to evaluate the safety of the secondary treatment agents.

METHODS

We retrospectively analyzed the data of patients with MP pneumonia hospitalized between January 2015 and April 2017. Macrolide-unresponsiveness was clinically defined with a persistent fever of ≥ 38.0°C at ≥ 72 hours after macrolide treatment. The cases were divided into four groups: PMC, CST, DXC, and LFX. We compared the time to defervescence (TTD) after secondary treatment and the TTD after initial macrolide treatment in each group with adjustment using propensity score-matching analysis.

RESULTS

Among 1,165 cases of MP pneumonia, 190 (16.3%) were unresponsive to macrolides. The proportion of patients who achieved defervescence within 48 hours in CST, DXC, and LFX groups were 96.9% (31/33), 85.7% (12/14), and 83.3% (5/6), respectively. The TTD after initial macrolide treatment did not differ between PMC and CST groups (5.1 vs. 4.2 days, P = 0.085), PMC and DXC groups (4.9 vs. 5.7 days, P = 0.453), and PMC and LFX groups (4.4 vs. 5.0 days, P = 0.283). No side effects were observed in the CST, DXC, and LFX groups.

CONCLUSION

The change to secondary treatment did not show better efficacy compared to PMC in children with macrolide-unresponsive MP pneumonia. Further studies are needed to guide appropriate treatment in children with MP pneumonia.

Antimicrobial Therapy in Community-Acquired Pneumonia in Children

PURPOSE OF REVIEW

Empirical antibiotic therapy remains the cornerstone of treatment in community-acquired pneumonia (CAP). However, the best option for empirical antibiotics for treatment on an ambulatory basis, as well as in those requiring hospitalization, is still unclear. This review tries to answer the question regarding the most appropriate antibiotics in different settings in children with CAP as well as duration of therapy.

RECENT FINDINGS

Recent studies have provided insights regarding use of oral antibiotics in children with mild to moderate CAP, and severe CAP with lower chest retractions but no hypoxia. In view of rapidly emerging resistance among various causative pathogens, several new drugs have been currently approved, or are under trial for CAP in children. Current knowledge suggests that the choice of antibiotics for ambulatory treatment of CAP is oral amoxicillin with a duration of 3-5 days. Children with CAP with lower chest retractions but no hypoxia can be treated with oral amoxicillin. Severe pneumonia can be treated with intravenous antibiotics consisting of penicillin/ampicillin with or without an aminoglycoside. Several new drugs have been developed and approved for use in CAP caused by multidrug-resistant organisms, but these should be used judiciously to avoid emergence of further resistance. Future research is needed regarding the safety and efficacy of newer drugs in children.