Molecular characterizations of PCR-positive Mycoplasma pneumoniae specimens collected from Australia and China

Disease burden and macrolide resistance of Mycoplasma pneumoniae infection in adults in the Asia-Pacific region

OBJECTIVES

In the Asia-Pacific region, Mycoplasma pneumoniae (MP) could be a notable pathogen responsible for adult community-acquired pneumonia (CAP), with varying prevalence rates. This comprehensive review aimed to explore the epidemiology, clinical manifestations, macrolide resistance, and molecular characteristics of MP in adults across several countries in Asia.

METHODS

PubMed, Embase, and Google Scholar were searched for relevant articles from 2010-2023 based on the following keywords: adult and Mycoplasma pneumoniae.

RESULTS

The prevalence of MP in CAP patients in these countries ranged from 2.1% in Korea to 25.5% in Japan. Macrolide resistance was prominent, particularly in China, with rates ranging 26.9-100%. Clinical manifestations of MP infection included protean extrapulmonary manifestations, and complications such as rhabdomyolysis and thrombocytopenia. Molecular characteristics, especially the multiple locus variable-number tandem-repeat analysis type 4/5/7/2, remained predominant across various countries, emphasising the importance of ongoing surveillance.

CONCLUSIONS

This review highlights the urgent need for continued monitoring of MP infections, macrolide resistance, and molecular characteristics to inform effective prevention and treatment strategies in the Asia-Pacific region.

Clinical Manifestations and Genomic Evaluation of Melioidosis Outbreak among Children after Sporting Event, Australia

Melioidosis, caused by the environmental gram-negative bacterium Burkholderia pseudomallei, usually develops in adults with predisposing conditions and in Australia more commonly occurs during the monsoonal wet season. We report an outbreak of 7 cases of melioidosis in immunocompetent children in Australia. All the children had participated in a single-day sporting event during the dry season in a tropical region of Australia, and all had limited cutaneous disease. All case-patients had an adverse reaction to oral trimethoprim/sulfamethoxazole treatment, necessitating its discontinuation. We describe the clinical features, environmental sampling, genomic epidemiologic investigation, and public health response to the outbreak. Management of this outbreak shows the potential benefits of making melioidosis a notifiable disease. The approach used could also be used as a framework for similar outbreaks in the future.

Molecular typing of Mycoplasma pneumoniae and its correlation with macrolide resistance in children in Henan of China

BACKGROUND/PURPOSE

As a major causative pathogen of community-acquired pneumonia, Mycoplasma pneumoniae (M. pneumoniae) can cause both upper and lower respiratory tract inflammation as well as extrapulmonary syndromes, especially in infants and the elderly. The emergence of macrolide-resistance has significant effects on the treatment of relevant diseases in children. This study aimed to analyze the genotypes and the macrolide resistance-associated mutations in M. pneumoniae sampled from the pediatric patients in Henan, China.

METHODS

A segment of gene on the 23S rRNA was amplified and sequenced to detect the mutations related to macrolide resistance. Molecular typing was performed by the method named multiple locus variable-number tandem repeat analysis (MLVA) for macrolide-susceptible and macrolide-resistant specimens.

RESULTS

Among the M. pneumoniae-positive samples, 95.7% (111/116) had macrolide-resistant mutation, and all of them consisted of the A2063G mutation. There were only two MLVA types identified in this study, type 4-5-7-2 (51/92, 55.4%) and type 3-5-6-2 (41/92, 44.6%).

CONCLUSION

There was no correlation between MLVA types and macrolide resistance (P ​> ​0.05).

Severe problem of macrolides resistance to common pathogens in China

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

Global Trends in the Proportion of Macrolide-Resistant Mycoplasma pneumoniae Infections: A Systematic Review and Meta-analysis

IMPORTANCE

The proportion of macrolide-resistant Mycoplasma pneumoniae (MRMP) infections has changed, and it differs according to geographical region.

OBJECTIVE

To analyze the global patterns, including the temporal trends, regional variations, and variant types, in the proportion of MRMP infections in this systematic review and meta-anaysis.

DATA SOURCES

PubMed, Cochrane Library, and Embase databases were searched for observational studies from inception to September 10, 2021.

STUDY SELECTION

Observational studies reporting the proportion of MRMP infections were screened independently by 2 authors. The presence of MRMP infection was defined as any case of M pneumoniae infection positive for any variants associated with macrolide resistance identified using respiratory samples.

DATA EXTRACTION AND SYNTHESIS

Data were extracted independently and in duplicate by 2 reviewers. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline was used. Random-effects meta-analyses were used to estimate the proportion of MRMP infections.

MAIN OUTCOMES AND MEASURES

The global patterns in the proportion of MRMP infections were estimated, and the temporal trends and variant types of MRMP infection with regional differences were investigated.

RESULTS

This study included 153 studies from 150 articles (27 408 samples in 26 countries) in the meta-analysis. The global patterns in the proportion of MRMP infections showed an increasing trend with regional differences. The proportion of MRMP infections was highest in the Western Pacific regions (53.4%; 95% CI, 47.4%-60.3%), followed by the South East Asian region (9.8%; 95% CI, 0.8%-100%), the region of the Americas (8.4%; 95% CI, 6.1%-11.6%), and the European region (5.1%; 95% CI, 3.3%-8.0%). The most commonly identified variant of MRMP infection was A2063G (96.8%; 95% CI, 95.8%-97.7%), followed by A2064G (4.8%; 95% CI, 3.5%-6.7%). The proportion of MRMP infections was the highest in studies including only children (37.0%; 95% CI, 29.8%-46.1%), followed by those including only adults (15.9%; 95% CI, 6.4%-39.7%) and those including both children and adults (16.7%; 95% CI, 10.1%-27.6%).

CONCLUSIONS AND RELEVANCE

This study provides global trends in the proportion of MRMP infections and suggests that strategies to prevent the spread of MRMP infection and to treat MRMP infections are needed to decrease disease burden.

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.

Molecular features and antimicrobial susceptibility of Mycoplasma pneumoniae isolates from pediatric inpatients in Weihai, China

OBJECTIVES

We analyzed the molecular features and antimicrobial susceptibility of Mycoplasma pneumoniae isolates from Weihai in 2019.

METHODS

Pharyngeal swabs of 160 pediatric patients with pneumonia-related symptoms were collected and subjected to culture and subsequent characteristic analysis. The characteristics of M. pneumoniae isolates were analyzed through real-time PCR and genotyping. Antimicrobial susceptibility test was performed against 4 antibiotics. All isolates were amplified for the analysis of macrolide (ML) resistant gene of the 23S rRNA and were genotyped with multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) and 'AGT' VNTR detection in p1 gene.

RESULTS

M. pneumoniae nucleic acid and culture positive rate of 160 specimens were 87.6% and 51.3%, respectively. Almost all isolates were ML resistant (81/82). Point mutation at 2063 site in 23S rRNA was identified in all ML resistant isolates. ML resistance rate of genotype 2 isolates was 97.6% in the M. pneumoniae isolates in Weihai. MLVA types 4/5/7/2 and 4/5/7/3 belonged to genotype 1, while 3/5/6/2 belonged to genotype 2. Numbers of 'AGT' VNTR in p1 gene from all isolates was in a range of 5-15.

CONCLUSIONS

This is the first report that the two genotypes of M. pneumoniae isolates were presented in relative equivalent ratio, with genotype 2 slightly dominant, in pediatric patients in Weihai in 2019, and the overall ML resistance rate was close to 100%. Minimum inhibitory concentration (MIC) of erythromycin in A2063T ML resistance in M. pneumoniae in Weihai was higher than previous publications.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

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

A multisite SNP genotyping and macrolide susceptibility gene method for Mycoplasma pneumoniae based on MALDI-TOF MS

In this study, a multisite SNP genotyping and macrolide (ML) susceptibility gene test method for Mycoplasma pneumoniae (M. pneumoniae) was developed based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The detection limit of this method for nucleic acids was 10² -10³ copies/reaction. Six SNP site-based genotyping and 3 ML susceptibility sites could be detected simultaneously based on multiplex PCR and mass probe. Using the method constructed in this study, 141 Chinese clinical isolates were divided into 8 SNP types. All the SNP test results for the ML susceptibility gene were in line with those of the 23S rRNA sequencing results. With this method, the multisite SNP genotyping and ML susceptibility determination of M. pneumoniae can be completed simultaneously in one test, which greatly reduces the workload and cost, improves the genotyping ability of M. pneumoniae and deserves clinical application.

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An all-in-one genotyping and macrolide resistance testing method for M. pneumoniae

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Multisite SNP detection technology was used for genotyping and resistance testing

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The cost of M. pneumoniae genotyping and macrolide resistance detection was reduced

Characterization of Legionella pneumophila Populations by Multilocus Variable Number of Tandem Repeats (MLVA) Genotyping from Drinking Water and Biofilm in Hospitals from Different Regions of the West Bank

The West Bank can be considered a high-risk area for Legionnaires' disease (LD) due to its hot climate, intermittent water supply and roof storage of drinking water. Legionella, mostly L. pneumophila, are responsible for LD, a severe, community-acquired and nosocomial pneumonia. To date, no extensive assessment of Legionella spp and L. pneumophila using cultivation in combination with molecular approaches in the West Bank has been published. Two years of environmental surveillance of Legionella in water and biofilms in the drinking water distribution systems (DWDS) of eight hospitals was carried out; 180 L. pneumophila strains were isolated, mostly from biofilms in DWDS. Most of the isolates were identified as serogroup (Sg) 1 (60%) and 6 (30%), while a minor fraction comprised Sg 8 and 10. Multilocus Variable number of tandem repeats Analysis using 13 loci (MLVA-8(12)) was applied as a high-resolution genotyping method and compared to the standard Sequence Based Typing (SBT). The isolates were genotyped in 27 MLVA-8(12) genotypes (Gt), comprising four MLVA clonal complexes (VACC 1; 2; 5; 11). The major fraction of isolates constituted Sequence Type (ST)1 and ST461. Most of the MLVA-genotypes were highly diverse and often unique. The MLVA-genotype composition showed substantial regional variability. In general, the applied MLVA-method made it possible to reproducibly genotype the isolates, and was consistent with SBT but showed a higher resolution. The advantage of the higher resolution was most evident for the subdivision of the large strain sets of ST1 and ST461; these STs were shown to be highly pneumonia-relevant in a former study. This shows that the resolution by MLVA is advantageous for back-tracking risk sites and for the avoidance of outbreaks of L. pneumophila. Overall, our results provide important insights into the detailed population structure of L. pneumophila, allowing for better risk assessment for DWDS.

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.

Antimicrobial susceptibility and molecular characteristics of Mycoplasma pneumoniae isolates across different regions of China

Background

In China mainland, most Mycoplasma pneumoniae related studies are carried out in Beijing and Shanghai, while rare studies are performed in the other regions. In this study, we analyzed the molecular biology characteristics and antimicrobial susceptibility of clinical isolates of M. pneumoniae from 5 regions between January 2017 and December 2018.

Methods

Genotyping was performed to 154 M. pneumoniae isolates from 5 cities using PCR and multiple-locus variable-number tandem repeat analysis (MLVA) method. Antimicrobial susceptibility test was performed to all the isolates against 4 antibiotics. Sequencing was performed to the amplification products of the 23S rRNA drug resistant gene.

Results

Genotype I was detected in 118 M. pneumoniae isolates (76.6%), and genotype II was identified in 36 isolates (23.4%). The majority (92.2%) of the MLVA genotypes were 4-5-7-2 and 3-5-6-2, which represented the genotype I and II, respectively. The total macrolide (ML) resistance rate was 79.7%. The minimum inhibitory concentration (MIC) of the erythromycin was in a range of 128- > 256 μg/ml, while that for the azithromycin was 2-32 μg/ml. There were mutations in the 23S rRNA in each ML resistance isolate. Jilin city showed the highest prevalence of genotype I (100%) and ML resistance rate (100%), while Jinan showed the lowest prevalence of genotype I (45.5%) and ML resistance rate (54.5%).

Conclusions

A large variance was identified in the M. pneumoniae genotype and ML resistance among the 5 cities. The proportion of M. pneumoniae with a genotype II genotype (3-5-6-2) showed an increased trend.

Polyclonal spread of multiple genotypes of Mycoplasma pneumoniae in semi-closed settings in Yamagata, Japan

PURPOSE

To clarify the spread of Mycoplasma pneumoniae infections in semi-closed settings such as schools and family homes using molecular typing methods.

METHODOLOGY

We retrospectively searched for school- and family-based clusters of M. pneumoniae infections based on information regarding patients from whom M. pneumoniae strains had been isolated between 2011 and 2013 in Yamagata, Japan. The molecular typing profile, including the P1 type and the four-locus (Mpn13, 14, 15 and 16) multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) type, was obtained from our previous study.

RESULTS

We identified 11 school-based clusters involving 71 patients and 16 family-based clusters involving 38 patients, including 14 duplications between these types of clusters. A total of 95M. pneumoniae strains isolated from those patients were divided into 4 genotypes: 33 strains of type 4-5-7-2, 1; 31 of type 4-5-7-3, 1; 24 of type 3-5-6-2, 2c; and 7 of type 3-5-6-2, 2a. Of the 11 school-based clusters, 6 clusters (54.5%) consisted of multiple genotypes, and the remaining 5 clusters consisted of a single genotype. Moreover, the presence of multiple genotypes was identified in three classrooms of a school. On the other hand, in 14 (87.5%) of the 16 family-based clusters, the genotypes of the M. pneumoniae strains isolated from each family member were identical.

CONCLUSION

The spread of M. pneumoniae infection in schools is likely polyclonal, since M. pneumoniae strains are brought into schools from various sites, such as family homes, which are important sites of disease transmission.

Antimicrobial susceptibility and genotyping of Mycoplasma pneumoniae isolates in Beijing, China, from 2014 to 2016

Background

The presence of macrolide-resistant Myocplasma pneumoniae has been frequently reported in recent years, especially in China. In this study, we investigated the antimicrobial susceptibility and genotype against M. pneumoniae isolates from 2014 to 2016, Beijing.

Methods

We investigated the activities of four antibiotics against 81 M. pneumoniae isolates in vitro. All isolates were amplification of domains II and V of the 23S rRNA gene and the L4 and L22 ribosomal protein fragments. All isolates were genotyped with duplex real-time PCR, MLVA and VNTR detection in p1 gene.

Results

The macrolide resistance rate was 65.4% (53/81). Each of the macrolide-resistant M. pneumoniae isolates was resistant to erythromycin (Minimum Inhibitory Concentration, MIC, ≥256 μg/ml) and azithromycin (MIC, 2-64 μg/ml), but susceptible to tetracycline and levofloxacin in vitro. Fifty two macrolide-resistant isolates harbored the A2063G mutation, and only 1 macrolide-resistant isolates harbored the A2064G mutation in domain V of the 23S ribosomal RNA gene. The C162A, A430G, and T279C mutations in the L4 and L22 ribosomal protein genes were not responsible for macrolide resistance, but they were related to the particular genotype of M. pneumoniae. 95.7% of type 1 isolates (45/47) were macrolide-resistance, and 23.5% of the type 2 isolates (8/34) were macrolide-resistance. Type 2 M. pneumoniae macrolide-resistance rate was 50.6% higher than that of the previous reports in China. The eight macrolide-resistant type 2 M. pneumoniae isolates were belong to 3/5/6/2 and 3/5/7/2 MLVA genotypes.

Conclusion

To our knowledge, this phenomenon likely resulted from a combination of genotype shifting from type1 to type 2 and antibiotic selection pressure in M. pneumoniae in China in recent years. The increase of resistance in type 2 is not due to the spread of same clone. However, the relationship between genotype shifts and macrolide resistance in M. pneumoniae needs to be further verified with more extensive surveillance data.

Molecular characterization of genomic DNA in mycoplasma pneumoniae strains isolated from serious mycoplasma pneumonia cases in 2016, Yunnan, China

Mycoplasma pneumoniae (MP) is particularly prevalent in low-immunity school-age children. Few data have been reported on MP prevalence in Yunnan, China. This study was designed to investigate the prevalence and characterize genomic DNA of MP in a small outbreak in 2016, Southwest China. RepMP4 and RepMP2/3 genes of MP positive samples were amplified for molecular typing through sequence alignment and PCR-RFLP assay. Phylogenetic trees were constructed by MEGA5.0. The results showed that two distinct P1 types (type I and type II) were prevalent in this MP outbreak. Type I was the most prevalent type, and clustered in the same evolutionary branch of C26 (China, 2012). Only 1 MP isolate belonged to type II, and clustered in the branch of KCH405 (Japan, 2016). Fifty-nine nucleotide mutations were observed in P1 genes of type I isolates (51 in RepMP4, 8 in RepMP2/3). Ninety-five nucleotide mutations were observed in P1 genes of the type II isolates (33 in RepMP4, 62 in RepMP2/3). It is noteworthy that 31 mutation sites were clustered in an 84-bp fragment in the RepMP4 gene of type II isolates. One new fragment that appeared in two of the type I strains was not found in NCBI. Nucleotide diversity analyze results showed that RepMP4 was more likely to be genetically diverse than RepMP2/3. Two-tailed Z-test result of RepMP4 suggested positive selection between 6 P1 type I isolates and M29 (China, 2005). According to secondary structure prediction, 36 new possible protein binding sites were found and another 9 sites were lost, 2 helices were missed and 1 new helix appeared in type I isolates. As for type II isolates, 16 protein binding regions were gained and 31 were lost. This study may help to understand the intrinsic geographical relatedness and contributes further to the research of MP.

[Association of drug resistance of Mycoplasma pneumoniae with DNA load and genotypes in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To investigate the association of drug resistance of Mycoplasma pneumoniae (MP) with DNA load and genotypes in children with MP pneumonia.

METHODS

A total of 230 children who were hospitalized and diagnosed with MP pneumonia between January 2012 and December 2016 were enrolled. Throat swabs were collected from the 230 children, and a rapid drug sensitivity assay was used to determine the sensitivity of clinical isolates of MP to nine commonly used antibacterial agents. Quantitative real-time PCR was used to measure MP-DNA load in throat swabs. PCR sequencing was used to determine the genotype of 2063 locus of the MP 23S rRNA V domain.

RESULTS

Of the 230 children, 86 (37.4%) had genotype A in 2063 locus, 134 (58.3%) had genotype G, 8 (3.5%) had genotype C, and 2 (0.9%) had genotype T. Mutant strains (genotype G+C+T) had a significantly higher MP-DNA load than wild-type strains (genotype A) (P<0.05). The strains resistant to erythromycin, azithromycin, clarithromycin, and clindamycin had a significantly higher MP-DNA load than non-resistant strains (P<0.05). MP had a high drug resistance rate to macrolide antibiotics. More than 60% of the cases with resistance to macrolides were found to have A2063G mutations. MP was rarely resistant to quinolones (less than 2%).

CONCLUSIONS

Mutations in 2063 locus of the MP 23S rRNA V domain may result in the resistance of MP to macrolides and the change in DNA load and can be used as a basis for selecting drugs for MP.

Multiple-Locus Variable-Number Tandem-Repeat Analysis of Mycoplasma pneumoniae Isolates between 2004 and 2014 in Yamagata, Japan: Change in Molecular Characteristics during an 11-year Period

Multiple-locus variable-number tandem-repeat analysis (MLVA) typing was performed for Mycoplasma pneumoniae strains isolated between 2004 and 2014 in Yamagata, Japan. The results were examined by considering the combination of the P1 type and prevalence of macrolide resistance-associated mutations. Four-locus (Mpn13-16) MLVA classified 347 strains into 9 MLVA types, including 3 major types: 3-5-6-2, 4-5-7-2, and 4-5-7-3. All type 3-5-6-2 strains (77 strains) were P1 type 2 variants (2a or 2c), while types 4-5-7-2 (181 strains) and 4-5-7-3 (75 strains) were P1 type 1. MLVA type 4-5-7-2 strains circulated and were dominant until 2010, accounting for 88.4% of the 121 strains isolated between 2004 and 2010. The prevalence of types 4-5-7-3 and 3-5-6-2 strains increased rapidly in 2011 and 2012, respectively, resulting in cocirculation of 3 MLVA types, including type 4-5-7-2, between 2011 and 2013. The prevalence of macrolide resistance-associated mutations in MLVA types 4-5-7-2, 4-5-7-3, and 3-5-6-2 strains was 59.7% (108/181), 25.3% (19/75), and 0% (0/77), respectively. Because the prevalence of macrolide resistance-associated mutations differed by current MLVA types in Yamagata, continued surveillance combined with molecular typing and identification of macrolide resistance-associated mutations is necessary.

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.

Molecular Characterization of Mycoplasma pneumoniae Infections in Two Rural Populations of Thailand from 2009 to 2012

Studies on Mycoplasma pneumoniae in Thailand have focused on urban centers and have not included molecular characterization. In an attempt to provide a more comprehensive understanding of this organism, we conducted a systematic random sampling to identify 3,000 nasopharyngeal swab specimens collected from January 2009 through July 2012 during population-based surveillance for influenza-like illness in two rural provinces. M. pneumoniae was detected by real-time PCR in 175 (5.8%) specimens. Genotyping was performed using the major adhesion protein (P1) and multilocus variable-number tandem-repeat analysis (MLVA). Of the 157 specimens typed, 97 were P1 type 1 and 60 were P1 type 2. Six different MLVA profiles were identified in 149 specimens, with 4/5/7/2 (40%) and 3/5/6/2 (26%) predominating. There was no discrete seasonality to M. pneumoniae infections. Examination of the 23S rRNA sequence for known polymorphisms conferring macrolide resistance revealed that all 141 tested to possess the genotype associated with macrolide susceptibility.

Encouraging rational antibiotic use in childhood pneumonia: a focus on Vietnam and the Western Pacific Region

Globally, pneumonia is considered to be the biggest killer of infants and young children (aged <5 years) outside the neonatal period, with the greatest disease burden in low- and middle-income countries. Optimal management of childhood pneumonia is challenging in settings where clinicians have limited information regarding the local pathogen and drug resistance profiles. This frequently results in unnecessary and poorly targeted antibiotic use. Restricting antibiotic use is a global priority, particularly in Asia and the Western Pacific Region where excessive use is driving high rates of antimicrobial resistance. The authors conducted a comprehensive literature review to explore the antibiotic resistance profile of bacteria associated with pneumonia in the Western Pacific Region, with a focus on Vietnam. Current management practices were also considered, along with the diagnostic dilemmas faced by doctors and other factors that increase unnecessary antibiotic use. This review offers some suggestions on how these issues may be addressed.

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.

Community-Acquired Pneumonia in the Asia-Pacific Region

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

[Application of Mycoplasma pneumoniae antibody and load index in the diagnosis of Mycoplasma pneumoniae pneumonia in children]

OBJECTIVE

To study the role of Mycoplasma pneumoniae (MP) load and antibody measurements in the diagnosis of MP pneumonia.

METHODS

A total of 115 children with MP pneumonia and 400 healthy children were enrolled. The MP load and total antibody level were measured at different stages, and the MP load index (MPLI) was calculated.

RESULTS

The cut-off value of MPLI for MP infection was 6.12. MPLI and total antibody titer increased during the course of the disease, while MP-DNA decreased rapidly. Within the same time of blood collection, the group with a higher MP load had a significantly higher total antibody titer than the group with a lower MP load (P<0.05). Within 2 weeks of the course of the disease, the negative antibody group had a significantly higher MPLI than the positive antibody group (P<0.05).

CONCLUSIONS

MPLI provides a standardized quantitative value of MP-DNA and plays an important role in the early diagnosis of MP infection.

[Application of Mycoplasma pneumoniae antibody and load index in the diagnosis of Mycoplasma pneumoniae pneumonia in children]

OBJECTIVE

To study the role of Mycoplasma pneumoniae (MP) load and antibody measurements in the diagnosis of MP pneumonia.

METHODS

A total of 115 children with MP pneumonia and 400 healthy children were enrolled. The MP load and total antibody level were measured at different stages, and the MP load index (MPLI) was calculated.

RESULTS

The cut-off value of MPLI for MP infection was 6.12. MPLI and total antibody titer increased during the course of the disease, while MP-DNA decreased rapidly. Within the same time of blood collection, the group with a higher MP load had a significantly higher total antibody titer than the group with a lower MP load (P<0.05). Within 2 weeks of the course of the disease, the negative antibody group had a significantly higher MPLI than the positive antibody group (P<0.05).

CONCLUSIONS

MPLI provides a standardized quantitative value of MP-DNA and plays an important role in the early diagnosis of MP infection.

Comparison of Molecular Characteristics of Mycoplasma pneumoniae Specimens Collected from the United States and China

Mycoplasma pneumoniae-positive clinical specimens obtained from the United States and China during the same period were studied for their molecular characteristics. We found much more diverse genotypes and a lower prevalence of macrolide resistance in the U.S. specimens. Data from the study also showed an association of the resistance with certain genotypes.

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.

No detection of macrolide-resistant Mycoplasma pneumoniae from Swedish patients, 1996-2013

BACKGROUND

Mycoplasma pneumoniae is a common cause of respiratory infections which can cause life-threatening pneumonia and serious extrapulmonary manifestations. Since the year 2000, the emergence of macrolide-resistant M. pneumoniae strains has increased with varying incidences across countries. In China more than 90% of the strains are resistant. M. pneumoniae diagnostics is mostly done with molecular methods, and in Sweden antibiotic resistance surveillance is not routinely performed. The prevalence of macrolide-resistant M. pneumoniae has not previously been studied in Sweden.

MATERIAL AND METHODS

A total of 563 M. pneumoniae-positive respiratory samples, collected from four counties in Sweden between 1996 and 2013, were screened for mutations associated with macrolide resistance using a duplex FRET real-time PCR method. The real-time PCR targets the 23S rRNA gene, and differentiation between wild-type and resistant strains was achieved with a melting curve analysis.

RESULTS

Of the 563 samples included, 548 were analyzed for mutations associated with macrolide resistance. No mutations were found. The detection rate of macrolide-resistant M. pneumoniae in this study was 0% [0.00-0.84%].

CONCLUSION

No macrolide-resistant M. pneumoniae has been detected in Sweden. However, the emergence and spread of macrolide-resistant M. pneumoniae strains in many countries commands continuous epidemiological surveillance.

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.

Th1/Th2 Cytokine Profile and Its Diagnostic Value in Mycoplasma pneumoniae Pneumonia

BACKGROUND

The levels of Th1/Th2 cytokine can alter in pathogenic infection in children with pneumonia.

OBJECTIVES

To evaluate Th1/Th2 cytokine profile and its diagnostic value in M. pneumoniae pneumonia in children.

PATIENTS AND METHODS

Children with M. pneumoniae mono-infection and 30 healthy children were tested with cytokines assay. We used real time PCR to detect M. pneumoniae in children with pneumonia.

RESULTS

M. pneumoniae test was positive in 2188 (16.62%) out of 13161 pneumonia children. Children aged 5 - 9 years had the highest rate and summer was a season with high rate of M. pneumoniae incidence in Zhejiang province. During the course of study, in 526 pneumonia children with M. pneumoniae mono-infection and 30 healthy children cytokines assay was performed. IL-2 level of M. pneumoniae pneumonia children was lower than that of healthy children (median levels, pg/mL: IL-2: 3.2 vs. 5.7, P = 0.00), while IL-4, IL-10 and IFN-γ were higher than in healthy children (median levels, pg/mL: IL-4: 3.2 vs. 1.5, P = 0.00; IL-10: 5.6 vs. 2.5, P = 0.001; IFN-γ: 20.4 vs. 4.8, P = 0.001).

CONCLUSIONS

IL-2 decreases and IL-4, IL-10 and IFN-γ increase in children with M. pneumoniae pneumonia, which has a promising prospect in diagnosis of this disease in clinical practice.

Culture-Independent Detection and Genotyping of Mycoplasma pneumoniae in Clinical Specimens from Beijing, China

A duplex real-time PCR assay was designed for simultaneous detection and genotyping of Mycoplasma pneumoniae (M. pneumoniae). The detection/typing performance of this duplex PCR method, targeting specific genes for M. pneumoniae type 1 (mpn 459) and type 2 (mpna 5864), was compared to that of the previously published MpP1 real-time PCR assay and the genotyping method for the adhesin P1 gene (mpn 141). A total of 1,344 throat swab specimens collected from patients in Beijing, China were tested for M. pneumoniae by bacterial culture, MpP1 real-time PCR assay, and our duplex PCR assay, and positive detection rates of 26.9%, 34.4%, and 33.7%, respectively, were obtained. The duplex PCR method demonstrated high sensitivity and accuracy for detecting and genotyping M. pneumoniae, and significant differences in genotyping ability were observed when compared to the conventional P1 gene-based method. M. pneumoniae type 1 was the predominate genotype from 2008 to 2012 in Beijing, and a shift from type 1 to type 2 began to occur in 2013. To our knowledge, this is the first reported incidence of a type shift phenomenon of M. pneumoniae clinical isolates in China. These genotyping results provide important information for understanding recent changes in epidemiological characteristics of M. pneumoniae in Beijing.

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.

Emergence of Macrolide-Resistant Mycoplasma pneumoniae in Hong Kong Is Linked to Increasing Macrolide Resistance in Multilocus Variable-Number Tandem-Repeat Analysis Type 4-5-7-2

Macrolide-resistant Mycoplasma pneumoniae (MRMP) is rapidly emerging in Asia, but information on the temporal relationship between the increase in macrolide resistance and changes in strain types is scarce. Between 2011 and 2014, M. pneumoniae infection was diagnosed by PCR as part of routine care in a health care region in Hong Kong. Testing was initiated by clinicians, mainly in patients with suspected M. pneumoniae pneumonia. Specimens positive for M. pneumoniae were retrospectively investigated by macrolide resistance genotyping and a four-locus (Mpn13 to -16) multilocus variable-number tandem-repeat analysis (MLVA) scheme. The overall percentage of M. pneumoniae-positive specimens was 17.9%, with annual rates ranging from 9.8% to 27.2%. The prevalence of MRMP had rapidly increased from 13.6% in 2011 to 30.7% in 2012, 36.6% in 2013, and 47.1% in 2014 (P = 0.038). Two major MLVA types, 4-5-7-2 and 3-5-6-2, accounted for 75% to 85% of the infections each year. MLVA types 4-5-7-2 and 3-5-6-2 predominated among macrolide-resistant and macrolide-sensitive groups, respectively. The increase in MRMP was mainly caused by increasing macrolide resistance in the prevalent MLVA type 4-5-7-2, changing from 25.0% in 2011 to 59.1% in 2012, to 89.7% in 2013, and to 100% in 2014 (P < 0.001). In conclusion, increasing MRMP in Hong Kong was linked to a single MLVA type, which was both prevalent and increasingly resistant to macrolides.

International Mycoplasma pneumoniae typing study: interpretation of M. pneumoniae multilocus variable-number tandem-repeat analysis

Typing of Mycoplasma pneumoniae by multiple-locus variable-number tandem repeat analysis (MLVA) is increasingly in use. However, no specific internationally agreed guidance is available. Thirty M. pneumoniae DNA samples including serial dilutions of a type strain were sent to six international laboratories to perform MLVA and results were compared. Good correlation was observed, indicating that this methodology can be robustly performed in multiple sites. However, differences due to interpretation of fragment size, repeat sequence identification and repeat numbering led to inconsistency in the final profiles assigned by laboratories. We propose guidelines for interpreting M. pneumoniae MLVA typing and assigning the number of repeats.