Nationwide surveillance of macrolide-resistant Mycoplasma pneumoniae infection in pediatric patients

Genotyping and macrolide resistance of Mycoplasma pneumoniae identified in children with community-acquired pneumonia in Medellín, Colombia

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The majority of the Mycoplasma pneumoniae isolates obtained from the children with community-acquired pneumonia in this study were a variant of type 2.

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There was an absence of the mutations in the 23S rRNA gene related to macrolide resistance.

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Induced sputum sample has higher percentage of positive PCR to diagnose Mycoplasma pneumoniae compared to nasopharyngeal swab.

Objectives

The aim of this study was to describe the genotypes and the main characteristics of community-acquired pneumonia (CAP) caused by Mycoplasma pneumoniae in hospitalized children in Medellín and neighboring municipalities during the period 2011–2012.

Methods

The M. pneumoniae genotype was determined by PCR and sequencing of the p1 and 23S rRNA genes from induced sputum samples and nasopharyngeal swabs (NPS). Samples were obtained from children with CAP who were hospitalized in 13 healthcare centers. In addition, a spatio-temporal analysis was performed to identify the potential risk areas and clustering of the cases over time.

Results

A variant of type 2 was the dominant genotype in the induced sputum (96.1%) and NPS (89.3%) samples; the type 1 variant was identified in 3.9% and 10.7% of these samples, respectively. No strains with mutations in the 23S rRNA gene associated with macrolide resistance were found. The cases in Medellín were mainly concentrated in the northeastern areas and western districts. However, no temporal relationship was found among these cases.

Conclusions

A variant of type 2 of M. pneumoniae prevailed among children with CAP during the study period. No strains with mutations associated with macrolide resistance were found.

Development of macrolide resistance-associated mutations after macrolide treatment in children infected with Mycoplasma pneumoniae

PURPOSE

To determine the timing of the emergence of macrolide-resistant mutations after macrolide treatment in individuals with Mycoplasma pneumoniae infections.

METHODOLOGY

Between October 2011 and December 2013, serial pharyngeal swab specimens were collected before and after macrolide treatment from 21 otherwise healthy children infected with M. pneumoniae without macrolide-resistant mutations. The copy numbers of a M. pneumoniae gene and the proportion of clones showing macrolide-resistance mutations were determined for each specimen.

RESULTS

After macrolide treatment (10-15 mg kg^-1 day^-1 clarithromycin for 5-10 days or 10 mg kg^-1 day^-1 azithromycin for 3 days), fever resolved in 19 (90 %) of 21 children within 1 to 2 days, and the M. pneumoniae gene copy number decreased in all but one specimen in the second set of specimens relative to the number in the corresponding initial specimens. None of the second specimens, which were collected 2-4 days after initiation of macrolide treatment, showed mutations in the 23S rRNA gene. However, the proportion of mutant clones with A2063G and A2064G mutations in the specimens collected 7-24 days after initiation of treatment increased to 100 %. We identified a family in which three members had M. pneumoniae infections. The analysis of transmission in this household indicated that the M. pneumoniae harbouring a macrolide-resistant mutation that developed in the index patient after macrolide treatment was not transmitted to the family members.

CONCLUSION

A macrolide-resistant population might develop in individual patients up to 24 days after initiation of macrolide treatment. However, the decrease in M. pneumoniae load after macrolide administration effectively reduces interpersonal transmission.

A Rare Case of Cavitary Lesion of the Lung Caused by Mycoplasma pneumoniae in an Immunocompetent Patient

Mycoplasma pneumoniae is an atypical bacterium that most commonly causes upper respiratory tract infections, but it can also cause pneumonia, referred to as "walking pneumonia." Although cavitary lesions are present in a wide variety of infectious and noninfectious processes, those attributable to M. pneumoniae are extremely uncommon; thus, to date, epidemiological studies are lacking. Here, we present a rare case of a 20-year-old male, referred to us from a psychiatric facility for evaluation of a cough, who was found to have a cavitary lesion in the right upper lobe. An extensive workup for cavitary lesion was negative, but his mycoplasma IgM level was high. A computed tomography (CT) of the chest confirmed the presence of a cavitary lesion. After treatment with levofloxacin antibiotics, a follow-up CT showed complete resolution of the lesion. Our case is a rare presentation of mycoplasma pneumonia as a cavitary lesion in a patient without any known risk factors predisposing to mycoplasma infection. Early recognition and treatment with an appropriate antibiotic may lead to complete resolution of the cavitary lesion.

A novel detection procedure for mutations in the 23S rRNA gene of Mycoplasma pneumoniae with peptide nucleic acid-mediated loop-mediated isothermal amplification assay

Rapid and easy detection of a single nucleotide point mutation of bacterial genes, which is directly linked to drug susceptibility, is essential for the proper use of antimicrobial agents. Here, we established a detection method using a peptide nucleic acid mediated loop-mediated amplification (LAMP) assay for macrolide (ML)-susceptible Mycoplasma pneumoniae. This assay specifically detected the absence of missense mutations encoding the central loop of domain V in the gene encoding 23S rRNA, which can reduce the affinity for MLs and subsequently generate ML-resistant strains of M. pneumoniae. Reactions were performed at 62°C for 60min and targeted gene amplifications were detected by real-time turbidity with a turbidimeter and naked-eye inspection of a color change. The assay had an equivalent detection limit of 100.0fg of DNA with the turbidimeter and showed specificity against 54 types of pathogens, whereas amplification was completely blocked, even at 100.0pg of DNA per reaction, in the presence of point mutations at 2063A and 2064A. The expected LAMP products were confirmed through identical melting curves in real-time LAMP procedures. This method would be a simple and rapid protocol for single nucleotide polymorphism genotyping as point-of-care testing technology without amplification of the sequences carrying the point mutations 2063A and 2064A in ML-resistant M. pneumoniae strains.

Treatment of preschool children presenting to the emergency department with wheeze with azithromycin: A placebo-controlled randomized trial

Background

Antibiotics are frequently used to treat wheezing children. Macrolides may be effective in treating bronchiolitis and asthma.

Method

We completed a prospective, double-blinded, randomized placebo-control trial of azithromycin among pre-school children (12 to 60 months of age) presenting to the emergency department with wheeze. Patients were randomized to receive either five days of azithromycin or placebo. Primary outcome was time to resolution of respiratory symptoms after treatment initiation. Secondary outcomes included the number of days children used a Short-Acting Beta-Agonists during the 21 day follow-up and time to disease exacerbation during the following six months (unscheduled health care visit or treatment with an oral corticosteroid for acute respiratory symptoms).

Results

Of the 300 wheezing children recruited, 222 and 169 were analyzed for the primary and secondary outcomes, respectively. The treatment groups had similar demographics and clinical parameters at baseline. Median time to resolution of respiratory symptoms was four days for both treatment arms (interquartile range (IQR) 3,6; p = 0.28). Median number of days of Short-Acting Beta-Agonist use among those who received azithromycin was four and a half days (IQR 2, 7) and five days (IQR 2, 9; p = 0.22) among those who received placebo. Participants who received azithromycin had a 0.91 hazard ratio for time to six-month exacerbation compared to placebo (95% CI 0.61, 1.36, p = 0.65). A pre-determined subgroup analysis showed no differences in outcomes for children with their first or repeat episode of wheezing. There was no significant difference in the proportion of participants experiencing an adverse event.

Conclusion

Azithromycin neither reduced duration of respiratory symptoms nor time to respiratory exacerbation in the following six months after treatment among wheezing preschool children presenting to an emergency department. There was no significant effect among children with either first-time or prior wheezing.

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.

Killing kinetics of minocycline, doxycycline and tosufloxacin against macrolide-resistant Mycoplasma pneumoniae

Macrolide-resistant Mycoplasma pneumoniae (MRMP) has emerged and is increasing worldwide. In a 2011 outbreak of MRMP infections in Japan, symptoms failed to improve in many patients who initially received macrolides; the therapeutic agent was then changed to minocycline (MIN), doxycycline (DOX) or tosufloxacin (TFX). In this study, the bactericidal effects of these three agents against MRMP were evaluated. Time-kill kinetics against MRMP and macrolide-susceptible M. pneumoniae (MSMP) were determined for 5 days at concentrations corresponding to the respective minimum inhibitory concentration (MIC) and 2 × MIC, i.e. 1 µg/mL and 2 µg/mL for MIN, 0.5 µg/mL and 1 µg/mL for DOX, and 0.5 µg/mL and 1 µg/mL for TFX. The post-antibiotic effects (PAE) of these agents in culture against MRMP were also examined based on their pharmacokinetic parameters in children. Following exposure of MRMP and MSMP to up to twice the respective MICs of MIN, DOX and TFX, viable cells initially numbering 10⁶ CFU/mL had decreased similarly to 10³ CFU/mL after 4 days. Clarithromycin and azithromycin showed good bactericidal action against MSMP but not against MRMP. PAEs against MRMP appeared superior with MIN and DOX compared with TFX. In infection with M. pneumoniae having a generation time exceeding 6 h, a therapeutic agent must be selected in consideration of pharmacokinetic parameters, not MICs alone.

Prevalence of inappropriate antibiotic prescriptions after the great east Japan earthquake, 2011

Few studies have investigated the appropriateness of antibiotic use in postdisaster settings. We retrospectively evaluated clinical databases on health care delivered at clinics near shelters set up after the Great East Japan Earthquake, 2011. We defined appropriate, acceptable, and inappropriate antibiotic use for each diagnostic category, by applying and adopting precedent studies and clinical guidelines. From March to July, 2011, a total of 23,704 clinic visits occurred at 98 shelters with 7934 residents. Oral antibiotics were prescribed a total of 2253 times. The median age of the patients was 48.5 years old (range 0-97), and 43.7% were male. Of 2253 antibiotic prescriptions, 1944 were judged to be inappropriate (86.3% 95% CI 84.8%-87.7%). The most prescribed antibiotic was clarithromycin (646 times, 28.7%), followed by cefcapene pivoxil (644 times, 28.6%), levofloxacin (380, 16.9%), cefdinir (194, 8.6%), and cefditren pivoxil (98, 4.4%). The most frequent diagnosis for which antibiotics were prescribed was upper respiratory infection (URI, 1040 visits, 46.2%), followed by acute bronchitis (369, 16.4%), pharyngitis (298, 13.2%), traumatic injuries (194, 8.6%), acute gastroenteritis (136, 6.0%), urinary tract infections (UTIs, 123, 5.5%), and allergic rhinitis (5.1%). The majority of antibiotics prescribed at clinics after the Great East Japan Earthquake was inappropriate. Significant improvement of the use of antibiotics in postdisaster settings should be sought immediately in Japan.

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.

Changes in Molecular Characteristics of Mycoplasma pneumoniae in Clinical Specimens from Children in Beijing between 2003 and 2015

The molecular characteristics of 480 Mycoplasma pneumoniae polymerase chain reaction-positive specimens (331 were previously reported and 149 were newly reported) collected from pediatric patients in Beijing, China, between 2003 and 2015 were analyzed. Genotype M4-5-7-2/P1 were the most prevalent across the 13-year study period, although the isolation and mutation rates for this genotype varied between the periods 2003-2007, 2008-2013, and 2014-2015. In addition, there was a close association between the M4-5-7-2 genotype and macrolide resistance.

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

PURPOSE

The aim of this study was to investigate the change in macrolide resistance rate in pediatric Mycoplasma pneumoniae pneumonia and to evaluate the influence of macrolide-resistant M. pneumoniae (MRMP) on the clinical course of disease, by comparing 2 recent, consecutive epidemics in Korea.

METHODS

A total of 250 patients with M. pneumoniae pneumonia admitted to a single tertiary hospital were enrolled in this study. Detection of MRMP was based on specific point mutations in domain V of the 23S rRNA gene. The medical records of enrolled patients were reviewed retrospectively, and the clinical courses and laboratory data were compared.

RESULTS

The macrolide resistance rate of M. pneumoniae was 51.1% (48/94) in the 2011 epidemic, and 87.2% (136/156) in the 2015 epidemic. All MRMP isolates had the A2063G point mutation. In comparison of 2 epidemics, the mean age of patients with M. pneumoniae pneumonia was increased, and the total febrile days and febrile days after initiation of macrolides were prolonged in the 2015 epidemic. Overall severity of MRMP or macrolide-susceptible M. pneumoniae (MSMP) pneumonia over 2 epidemics was not significantly changed. However, the proportion of patients who had a fever lasting more than 72 hours after initiation of macrolides and who received corticosteroid treatment were higher in MRMP pneumonia during 2 epidemics.

CONCLUSIONS

The macrolide resistance rate of M. pneumoniae has risen rapidly over 2 recent, consecutive epidemics, and this has been associated with a prolonged clinical course and increased use of corticosteroids to treat pediatric M. pneumoniae pneumonia.

Development of an endpoint genotyping assay to detect the Mycoplasma pneumoniae 23S rRNA gene and distinguish the existence of macrolide resistance-associated mutations at position 2063

The prevalence of macrolide-resistant Mycoplasma pneumoniae harboring a mutation in the 23S rRNA gene is increasing, and rapid detection assays are needed for clinical management. We developed an endpoint genotyping assay to detect the M. pneumoniae 23S rRNA gene and determine the existence of macrolide resistance-associated mutations at position 2063 (A2063G, A2063T and A2063C mutations). This A2063B genotyping assay detected more than 50 copies/reaction of the M. pneumoniae gene in every nucleotide mutation at position 2063. Of 42 clinical specimens, 3 were positive without mutation, 6 were positive with the A2063G mutation, and 33 were negative. The results were confirmed using nested PCR with the sequencing of the M. pneumoniae 23S rRNA gene, and a high sensitivity (90%), specificity (100%), and coincidence ratio (kappa coefficient=0.93) were obtained. Therefore, the A2063B genotyping assay is useful for the rapid discrimination of macrolide resistance mutations at position 2063.

Resistance to Macrolide Antibiotics in Public Health Pathogens

Macrolide resistance mechanisms can be target-based with a change in a 23S ribosomal RNA (rRNA) residue or a mutation in ribosomal protein L4 or L22 affecting the ribosome's interaction with the antibiotic. Alternatively, mono- or dimethylation of A2058 in domain V of the 23S rRNA by an acquired rRNA methyltransferase, the product of an erm (erythromycin ribosome methylation) gene, can interfere with antibiotic binding. Acquired genes encoding efflux pumps, most predominantly mef(A) + msr(D) in pneumococci/streptococci and msr(A/B) in staphylococci, also mediate resistance. Drug-inactivating mechanisms include phosphorylation of the 2'-hydroxyl of the amino sugar found at position C5 by phosphotransferases and hydrolysis of the macrocyclic lactone by esterases. These acquired genes are regulated by either translation or transcription attenuation, largely because cells are less fit when these genes, especially the rRNA methyltransferases, are highly induced or constitutively expressed. The induction of gene expression is cleverly tied to the mechanism of action of macrolides, relying on antibiotic-bound ribosomes stalled at specific sequences of nascent polypeptides to promote transcription or translation of downstream sequences.

Two case reports: Whole genome sequencing of two clinical macrolide-resistant Mycoplasma pneumoniae isolates with different responses to azithromycin

BACKGROUND

Cases of macrolide-resistant Mycoplasma pneumoniae have increased rapidly since 2000, especially in Asia. Patients infected with macrolide-resistant M pneumoniae usually present with severe M pneumoniae pneumonia. The aim of this study was to identify indicators for whether children at an early stage of M pneumoniae infection develop mild or severe pneumonia.

CASE SUMMARY

Herein, we retrospectively reviewed 2 pediatric cases caused by macrolide-resistant M pneumoniae, but with markedly different severity of pneumonia. First, we compared the clinical courses of the patients, then isolated the pathogens and tested their response to macrolides, then finally, carried out whole genome sequencing of these isolates. Despite the difference in clinical presentation of the infection, both isolates exhibited a high level of resistance to macrolide antibiotics. Analysis of clinical data showed that the erythrocyte sedimentation rate in blood samples of the patients in the early stages of disease varied greatly. Genome sequence analysis revealed single nucleotide polymorphisms mainly focused on adhesin P1, which is involved in the pathogenicity of M pneumoniae.

CONCLUSION

The differences of erythrocyte sedimentation rate in the early stage of M pneumoniae pneumonia and mutations in P1 protein may help us to distinguish between severe or mild disease after infection with macrolide-resistant M pneumoniae. These findings could lead to the development of screening assays that will allow us to distinguish severe or mild M pneumoniae pneumonia early.

Japanese antimicrobial consumption surveillance: First report on oral and parenteral antimicrobial consumption in Japan (2009-2013)

No reliable national antimicrobial consumption data have been available in Japan. The Japanese antimicrobial consumption surveillance (JACS) project started to collect data nationwide on antimicrobial consumption. This paper provides the first sales data from the JACS project on oral and parenteral antimicrobial consumption in Japan as well as the trends for the years from 2009 to 2013. The population-weighted total consumption was expressed as defined daily doses (DDDs) per 1000 inhabitants per day (DID). The value of DID increased from 14.7 in 2009 to 15.8 in 2013. Notably, oral antimicrobials accounted for 92.6% (mean of 2009, 2011 and 2013) of total consumption. Oral third-generation cephalosporins, macrolides and fluoroquinolones accounted for 77.1% (mean of 2009, 2011 and 2013) of oral consumption. Consumption of antimicrobials has increased during the years 2009 and 2013 regardless of the dosage form. This is the first report regarding the population-weighted consumption of oral and parenteral antimicrobials in Japan during the years 2009 and 2013. These results provide useful information for combating the menace of antimicrobial resistance in Japan.

Mycoplasma pneumoniae: Current Knowledge on Macrolide Resistance and Treatment

Mycoplasma pneumoniae causes community-acquired respiratory tract infections, particularly in school-aged children and young adults. These infections occur both endemically and epidemically worldwide. M. pneumoniae lacks cell wall and is subsequently resistant to beta-lactams and to all antimicrobials targeting the cell wall. This mycoplasma is intrinsically susceptible to macrolides and related antibiotics, to tetracyclines and to fluoroquinolones. Macrolides and related antibiotics are the first-line treatment of M. pneumoniae respiratory tract infections mainly because of their low MIC against the bacteria, their low toxicity and the absence of contraindication in young children. The newer macrolides are now the preferred agents with a 7-to-14 day course of oral clarithromycin or a 5-day course of oral azithromycin for treatment of community-acquired pneumonia due to M. pneumoniae, according to the different guidelines worldwide. However, macrolide resistance has been spreading for 15 years worldwide, with prevalence now ranging between 0 and 15% in Europe and the USA, approximately 30% in Israel and up to 90–100% in Asia. This resistance is associated with point mutations in the peptidyl-transferase loop of the 23S rRNA and leads to high-level resistance to macrolides. Macrolide resistance-associated mutations can be detected using several molecular methods applicable directly from respiratory specimens. Because this resistance has clinical outcomes such as longer duration of fever, cough and hospital stay, alternative antibiotic treatment can be required, including tetracyclines such as doxycycline and minocycline or fluoroquinolones, primarily levofloxacin, during 7–14 days, even though fluoroquinolones and tetracyclines are contraindicated in all children and in children < 8 year-old, respectively. Acquired resistance to tetracyclines and fluoroquinolones has never been reported in M. pneumoniae clinical isolates but reduced susceptibility was reported in in vitro selected mutants. This article focuses on M. pneumoniae antibiotic susceptibility and on the development and the evolution of acquired resistance. Molecular detection of resistant mutants and therapeutic options in case of macrolide resistance will also be assessed.

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

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

A Compendium for Mycoplasma pneumoniae

Historically, atypical pneumonia was a term used to describe an unusual presentation of pneumonia. Currently, it is used to describe the multitude of symptoms juxtaposing the classic symptoms found in cases of pneumococcal pneumonia. Specifically, atypical pneumonia is a syndrome resulting from a relatively common group of pathogens including Chlamydophila sp., and Mycoplasma pneumoniae. The incidence of M. pneumoniae pneumonia in adults is less than the burden experienced by children. Transmission rates among families indicate children may act as a reservoir and maintain contagiousness over a long period of time ranging from months to years. In adults, M. pneumoniae typically produces a mild, “walking” pneumonia and is considered to be one of the causes of persistent cough in patients. M. pneumoniae has also been shown to trigger the exacerbation of other lung diseases. It has been repeatedly detected in patients with bronchitis, asthma, chronic obstructive pulmonary disorder, and cystic fibrosis. Recent advances in technology allow for the rapid diagnosis of M. pneumoniae through the use of polymerase chain reaction or rapid antigen tests. With this, more effort has been afforded to identify the causative etiologic agent in all cases of pneumonia. However, previous practices, including the overprescribing of macrolide treatment in China and Japan, have created increased incidence of macrolide-resistant M. pneumoniae. Reports from these countries indicate that >85% of M. pneumoniae pneumonia pediatric cases are macrolide-resistant. Despite its extensively studied past, the smallest bacterial species still inspires some of the largest questions. The developments in microbiology, diagnostic features and techniques, epidemiology, treatment and vaccines, and upper respiratory conditions associated with M. pneumoniae in adult populations are included within this review.

Complete Genome Sequence of the Macrolide-Resistant Mycoplasma pneumoniae Strain C267 in China

Macrolide-resistantMycoplasma pneumoniaestrains can cause severeM. pneumoniaepneumonia in children. Here, we report the complete genome sequence of the macrolide-resistantM. pneumoniaestrain C267, deposited in GenBank under accession number CP014267, which provides new insights for other potential macrolide-resistant mechanisms inM. pneumoniaeclinical isolates in China.

Macrolide-Resistant Mycoplasma pneumoniae, United States

Macrolide-resistant Mycoplasma pneumoniae (MRMP) is highly prevalent in Asia and is now being reported from Europe. Few data on MRMP are available in the United States. Using genotypic and phenotypic methods, we detected high-level MRMP in 13.2% of 91 M. pneumoniae­–positive specimens from 6 US locations.

[Evaluation of a Rapid Antigen Detection Kit Targeting L7/L12 Ribosomal Protein for Mycoplasma pneumoniae]

We evaluated the usefulness of a rapid antigen detection assay for L7/L12 ribosomal protein (Ribotest Mycoplasma; Asahi Kasei Pharma) for diagnosis of Mycoplasma pneumoniae (M. pneumoniae) infection. Nasopharyngeal swabs were obtained from patients with pneumonia and/or bronchitis; real-time PCR and the L 7/L12 antigen assays were performed with each sample. Serum was also taken from each patient, and the particle agglutination (PA) method was used to detect anti-M. pneumoniae antibody in these samples. Macrolide-resistance genes were detected and M. pneumoniae P1 protein subtyping was performed on PCR-positive samples. PCR assays were positive for 85 of 212 specimens (40.1%). Sensitivity and specificity of the L7/L12 antigen assays relative to the PCR standard were 74.1% (63/85) and 81.1% (103/127), respectively. For PCR-positive specimens with a large quantity of M. pneumoniae nucleic acid, sensitivity of the L7/L12 antigen assays seemed to be high. In PCR-positive specimens with fewer than 1.0 x 10(6) copies/mL of M. pneumoniae nucleic acid, sensitivity of the L7/L12 antigen assays seemed to be low. When the PA method was used as the standard, the relative sensitivity and specificity of the L7/L12 antigen assays were 41.7% (5/12) and 75.3% (58/77), respectively, for single serum and 60.9% (14/23) and 85.7% (18/21), respectively, for paired sera. The macrolide-resistance gene A2063G was detected in 20 of the 30 tested PCR-positive specimens (66.7%). Of these 20 A2063G-positive specimens, 13 (65.0%) were positive for the L7/L12 antigen assays. Tne numbers of M. pneumoniae P1 subtypes were as follows: types I (22), IIa(2), IIc(1), and untypable (5). The L7/L12 antigen assays gave positive results for 17 of 21 (81.0%) subtype I, 1 of 2 (50.0%) IIa, and 1 of 1(100%) IIc specimens.

P40 and P90 from Mpn142 are Targets of Multiple Processing Events on the Surface of Mycoplasma pneumoniae

Mycoplasma pneumoniae is a significant cause of community acquired pneumonia globally. Despite having a genome less than 1 Mb in size, M. pneumoniae presents a structurally sophisticated attachment organelle that (i) provides cell polarity, (ii) directs adherence to receptors presented on respiratory epithelium, and (iii) plays a major role in cell motility. The major adhesins, P1 (Mpn141) and P30 (Mpn453), are localised to the tip of the attachment organelle by the surface accessible cleavage fragments P90 and P40 derived from Mpn142. Two events play a defining role in the formation of P90 and P40; removal of a leader peptide at position 26 (²³SLA↓NTY²⁸) during secretion to the cell surface and cleavage at amino acid 455 (⁴⁵²GPL↓RAG⁴⁵⁷) generating P40 and P90. Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) analysis of tryptic peptides generated by digesting size-fractionated cell lysates of M. pneumoniae identified 15 cleavage fragments of Mpn142 ranging in mass from 9–84 kDa. Further evidence for the existence of cleavage fragments of Mpn142 was generated by mapping tryptic peptides to proteins recovered from size fractionated eluents from affinity columns loaded with heparin, fibronectin, fetuin, actin, plasminogen and A549 surface proteins as bait. To define the sites of cleavage in Mpn142, neo-N-termini in cell lysates of M. pneumoniae were dimethyl-labelled and characterised by LC-MS/MS. Our data suggests that Mpn142 is cleaved to generate adhesins that are auxiliary to P1 and P30.

Incident asthma and Mycoplasma pneumoniae: A nationwide cohort study

BACKGROUND

Previous studies investigating the relationship between Mycoplasma pneumoniae and incident asthma in the general population have been inconclusive.

OBJECTIVE

We conducted a nationwide cohort study to clarify this relationship.

METHODS

Using the National Health Insurance Research Database of Taiwan, we identified 1591 patients with M pneumoniae infection (International Classification of Diseases, Ninth Revision, Clinical Modification code 4830) given diagnoses between 2000 and 2008. We then frequency matched 6364 patients without M pneumoniae infection from the general population according to age, sex, and index year. Cox proportional hazards regression analysis was performed to determine the adjusted hazard ratio (aHR) of the occurrence of asthma in the M pneumoniae cohort compared with that in the non-M pneumoniae cohort.

RESULTS

Regardless of comorbidities and the use of antibiotic or steroid therapies, patients with M pneumonia infection had a higher risk of incident asthma than those without it. The aHR of asthma was 3.35 (95% CI, 2.71-4.15) for the M pneumoniae cohort, with a significantly higher risk when patients were stratified by age, sex, follow-up time, and comorbidities, including allergic rhinitis, atopic dermatitis, or allergic conjunctivitis. Patients with M pneumoniae infection had a higher risk of having early-onset (age, <12 years; aHR, 2.87) and late-onset (age, ≥12 years; aHR, 3.95) asthma. The aHR was also higher within the less than 2-year follow-up in the M pneumoniae cohort (aHR, 4.41; 95% CI, 3.40-5.74) than in the cohort without the infection.

CONCLUSION

This study found that incident cases of early-onset and late-onset asthma are closely related to M pneumoniae infection, even in nonatopic patients.

Overview of antimicrobial options for Mycoplasma pneumoniae pneumonia: focus on macrolide resistance

BACKGROUND AND AIMS

Community-acquired pneumonia (CAP) is a common infectious disease affecting children and adults of any age. Mycoplasma pneumoniae has emerged as leading causative agent of CAP in some region, and the abrupt increasing resistance to macrolide that widely used for management of M. pneumoniae has reached to the level that it often leads to treatment failures.

OBJECTIVE

We aim to discuss the drivers for development of macrolide-resistant M. pneumoniae, antimicrobial stewardship and also the potential treatment options for patients infected with macrolide-resistant M. pneumonia.

METHODS

The articles in English and Chinese published in Pubmed and in Asian medical journals were selected for the review.

RESULTS

M. pneumoniae can develop macrolide resistance by point mutations in the 23S rRNA gene. Inappropriate and overuse of macrolides for respiratory tract infections may induce the resistance rapidly. A number of countries have introduced the stewardship program for restricting the use of macrolide. Tetracyclines and fluoroquinolones are highly effective for macrolide-resistant strains, which may be the substitute in the region of high prevalence of macrolide-resistant M. pneumoniae.

CONCLUSION

The problem of macrolide resistant M. pneumonia is emerging. Antibiotic stewardship is needed to inhibit the inappropriate use of macrolide and new antibiotics with a more acceptable safety profile for all ages need to be explored.

Lactate Dehydrogenase as a Biomarker for Prediction of Refractory Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND

Corticosteroids have been used for refractory Mycoplasma pneumoniae pneumonia and have beneficial effects. The aim of this study was to identify the biomarkers for predicting refractory M. pneumoniae pneumonia in a timely fashion to initiate steroid therapy.

METHODS

This was a prospective cohort study of children with M. pneumoniae pneumonia admitted to the Children's Hospital of Fudan University from September 2012 to August 2013. Lactate dehydrogenase (LDH) and other laboratory tests, including complete blood counts, C-reactive protein, erythrocyte sedimentation rate (ESR), alanine aminotransferase, aspartate aminotransferase, α-hydroxybutyrate dehydrogenase (HBDH), creatine kinase, and creatine kinase MB, were performed on admission. Based on the definition of refractory M. pneumoniae pneumonia, subjects were divided into 2 groups: refractory M. pneumoniae pneumonia and usual M. pneumoniae pneumonia. The diagnostic values of laboratory findings were analyzed.

RESULTS

In total, 653 subjects were enrolled, including 300 in the refractory pneumonia group and 353 in the usual pneumonia group. There was no significant difference in sex distribution between the 2 groups. The average age in the refractory M. pneumoniae pneumonia group was greater than that in the usual M. pneumoniae pneumonia group. Compared with the usual pneumonia group, the refractory pneumonia group showed significantly higher levels of C-reactive protein, serum LDH, serum HBDH, serum alanine aminotransferase, serum aspartate aminotransferase, and neutrophils and higher ESRs. Logistic regression showed that age, LDH, and ESR were the significant factors in predicting refractory M. pneumoniae pneumonia. In addition, LDH and HBDH were strongly correlated, and receiver operating characteristic curve analysis showed that the area under the curve of LDH was 0.718 with a cutoff of 379 IU/L, that of ESR was 0.683 with a cutoff of 32.5 IU/L, and that of HBDH was 0.691 with a cutoff of 259.5 IU/L.

CONCLUSIONS

Serum LDH can be used as a biomarker to predict refractory M. pneumoniae pneumonia at the early stage of hospitalization.

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.

Diagnostic sensitivity of a rapid antigen test for the detection of Mycoplasma pneumoniae: Comparison with real-time PCR

A rapid antigen kit for the detection of the Mycoplasma pneumoniae ribosomal protein L7/L12 using an immunochromatographic assay, Ribotest Mycoplasma, became available in Japan in 2013. To determine the sensitivity of Ribotest compared with real-time polymerase chain reaction (PCR), we prospectively performed these two tests simultaneously in adolescent and adult patients with community-acquired pneumonia (CAP). In addition, we retrospectively analyzed the theoretical sensitivity of Ribotest using M. pneumoniae PCR-positive specimens from previous studies. In prospective study, 118 CAP cases were enrolled, and 16 cases were diagnosed as M. pneumoniae pneumonia; eight cases were PCR-positive, one case was culture positive, and all cases demonstrated a four-fold increase in antibody titer. Ribotest was positive in 15 cases; five cases were PCR positive and 10 cases were PCR negative. For the PCR was control test, the sensitivity, specificity, and overall agreement with Ribotest were 62.5%, 90.9%, and 88.9%, respectively. In the retrospective study, we used 1110 M. pneumoniae PCR-positive specimens, which are collected from pediatric patients with respiratory tract infection who visited 65 institutions throughout Japan. Using a cut-off level for the Ribotest of 8.3 × 10(4) copy/mL in transport medium, 667 (60.0%) specimens were theoretically positive. In conclusion, our prospective and retrospective results demonstrated that the diagnostic sensitivity of Ribotest compared with PCR was not high, at approximately 60%. Thus, treatment decisions about M. pneumoniae pneumonia should be based on clinical findings such as Japanese Respiratory Society scoring system and not on Ribotest results alone.

[Gene Mutations Associated with Macrolide-resistance and p1 Gene Typing of Mycoplasma pneumoniae Isolated in Yamagata, Japan, between 2004 and 2013]

To clarify the epidemiologic features of Mycoplasma pneumoniae, we examined 358 M. pneumoniae strains isolated between 2004 and 2013 in Yamagata, Japan. Analysis of macrolide-resistance-associated 23S ribosomal RNA (rRNA) domain V mutations revealed 6 kinds of mutants (81 A2063G, 43 A2063T, 1 A2063C, 1 A2064C, 4 C2617G and 1 C2617 mutation). There were only two mutants before 2009, but mutants A2063T and A2063G increased in 2009 and from 2010, respectively. The annual ratio of mutants varied from 20.4% to 76.4% between 2009 and 2013. Typing of the p1 gene revealed 4 types; 278 type 1, and 3 kinds of type 2 variant strains (10 type 2a, 5 type 2b and 65 type 2c). Type 1 strains accounted for between 85.2% and 100% of isolates from 2004 to 2011, whereas type 2 variant strains increased by 26.5% and 66.1% in 2012 and 2013, respectively. These results indicate that type 1 strains may have been replaced by type 2 variant strains in 2013. Furthermore, the ratio of type 1 strains with a 23S rRNA mutation was 65.1% in 2012 and 95.2% in 2013, but none of the type 2 variant strains had this mutation. In conclusion, type 1 strains with macrolide-resistant mutations appeared in 2006 and increased from 2009. In contrast, type 2 variant strains, which increased in 2012 and became predominant in 2013, showed no mutations.

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.

[Why use long-term macrolide therapy in pediatric pulmonology?]

Macrolides are well-known antibiotics exerting antimicrobial as well as anti-inflammatory and immunomodulatory effects. Since the observation of a dramatic improvement in lung disease and survival in patients with diffuse panbronchiolitis, macrolides have been used over the long term in several chronic respiratory diseases. This review describes the results of trials that have evaluated long-term macrolides in the treatment of cystic fibrosis, non-cystic fibrosis bronchiectasis, and asthma, particularly focusing on the impact on children. It also provides new insights on the potential effects of macrolides on diffuse parenchymal lung diseases.

Gene and cytokine profile analysis of macrolide-resistant Mycoplasma pneumoniae infection in Fukuoka, Japan

Background

Recent epidemiologic data suggest that the prevalence of macrolide resistant Mycoplasma pneumoniae (MR-M. pneumoniae) is increasing rapidly worldwide. This study assessed the present status of M. pneumoniae infection in Japan and clinical end-points to distinguish children with MR-M. pneumoniae.

Methods

During an outbreak of M. pneumoniae infections in Fukuoka, Japan in 2010–11, a total of 105 children with clinically suspected M. pneumoniae infection were enrolled. M. pneumoniae was analyzed for macrolide resistance in domain V of the 23S rRNA gene. Sixty -five patients with PCR positive for M. pneumoniae were analyzed with regard to clinical symptoms, efficacy of several antimicrobial agents and several laboratory data.

Results

Causative pathogens were detected in 81.0% (85 of 105) and M. pneumoniae was identified 61.9% (65 of 105). The resistance rate of M. pneumoniae was 89.2% (58 of 65) in this general pediatric outpatient setting. Patients infected with MR-M. pneumoniae showed longer times to resolution of fever and required frequent changes of the initially prescribed macrolide to another antimicrobial agent. We observed three different genotypes of M. pneumoniae including the rarely reported A2063T mutation (A2063G: 31 strains, A2063T: 27 strains, no mutation: 7 strains). Drug susceptibility testing showed different antimicrobial susceptibility profiles for each genotype. Serum IFN-gamma, IL-6 and IP-10 levels were higher in patients with MR-genotypes than in those infected with no-mutation strains (p < 0.001).

Conclusions

Macrolide resistance is more common than previously thought and a small epidemic of rarely reported A2063T mutation was observed in Fukuoka, Japan. Furthermore our results reveal the possibility that levels of certain inflammatory cytokines may be a candidate to predict MR-M.pneumoniae infection.