Mycoplasma pneumoniae Monoclonal P1 Type 2c Outbreak, Russia, 2013

Genotyping of Mycoplasma pneumoniae strains isolated in Japan during 2019 and 2020: spread of p1 gene type 2c and 2j variant strains

We characterized 118 Mycoplasma pneumoniae strains isolated from three areas of Japan (Saitama, Kanagawa, and Osaka) during the period of 2019 and 2020. Genotyping of the p1 gene in these strains revealed that 29 of them were type 1 lineage (29/118, 24.6%), while 89 were type 2 lineage (89/118, 75.4%), thereby indicating that type 2 lineage was dominant in this period. The most prevalent variant of type 2 lineage was type 2c (57/89, 64%), while the second-most was type 2j, a novel variant identified in this study (30/89, 33.7%). Type 2j p1 is similar to type 2 g p1, but cannot be distinguished from reference type 2 (classical type 2) using the standard polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) with HaeIII digestion. Thus, we used MboI digestion in the PCR-RFLP analysis and re-examined the data from previous genotyping studies as well. This revealed that most strains reported as classical type 2 after 2010 in our studies were actually type 2j. The revised genotyping data showed that the type 2c and 2j strains have been spreading in recent years and were the most prevalent variants in Japan during the time-period of 2019 and 2020. We also analyzed the macrolide-resistance (MR) mutations in the 118 strains. MR mutations in the 23S rRNA gene were detected in 29 of these strains (29/118, 24.6%). The MR rate of type 1 lineage (14/29, 48.3%) was still higher than that of type 2 lineage (15/89, 16.9%); however, the MR rate of type 1 lineage was lower than that found in previous reports published in the 2010s, while that of type 2 lineage strains was slightly higher. Thus, there is a need for continuous surveillance of the p1 genotype and MR rate of M. pneumoniae clinical strains, to better understand the epidemiology and variant evolution of this pathogen, although M. pneumoniae pneumonia cases have decreased significantly since the COVID-19 pandemic.

Molecular Characterization of Mycoplasma pneumoniae Isolates in the United States from 2012 to 2018

Mycoplasma pneumoniae is a major cause of community-acquired pneumonia. There are limited data in the United States on the molecular epidemiological characteristics of M. pneumoniae. We collected 446 M. pneumoniae-positive specimens from 9 states between August 2012 and October 2018. Culture, antimicrobial susceptibility testing, P1 subtyping, and multilocus VNTR (variable-number tandem repeats) analysis (MLVA) were performed to characterize the isolates.

Mycoplasma pneumoniae is a major cause of community-acquired pneumonia. There are limited data in the United States on the molecular epidemiological characteristics of M. pneumoniae. We collected 446 M. pneumoniae-positive specimens from 9 states between August 2012 and October 2018. Culture, antimicrobial susceptibility testing, P1 subtyping, and multilocus VNTR (variable-number tandem repeats) analysis (MLVA) were performed to characterize the isolates. Macrolide-resistant M. pneumoniae (MRMp) was detected in 37 (8.3%) specimens. P1 subtype 2 (P1-2) was the predominant P1 subtype (59.8%). P1 subtype distribution did not change significantly chronologically or geographically. The macrolide resistance rate in P1 subtype 1 (P1-1) samples was significantly higher than that in P1-2 (12.9% versus 5.5%). Six P1-2 variants were identified, including two novel types, and variant 2c was predominant (64.6%). P1-2 variants were distributed significantly differently among geographic regions. Classical P1-2 was more frequent in lower respiratory tract specimens and had longer p1 trinucleotide repeats. Classical P1-2 was most common in MRMp (35.7%), while variant 2c was most common in macrolide-susceptible M. pneumoniae (67.5%). Fifteen MLVA types were identified; 3-5-6-2 (41.7%), 4-5-7-2 (35.3%), and 3-6-6-2 (16.6%) were the major types, and four MLVA clusters were delineated. The distribution of MLVA types varied significantly over time and geographic location. The predominant MLVA type switched from 4-5-7-2 to 3-5-6-2 in 2015. MLVA type was associated with P1 subtypes and P1-2 variant types but not with macrolide resistance. To investigate the M. pneumoniae genotype shift and its impact on clinical presentations, additional surveillance programs targeting more diverse populations and prolonged sampling times are required.

Comparison of Nucleic Acid Amplification and IgM Tests for the Diagnosis of Mycoplasma pneumoniae Infection in Children During a Recent Korean Outbreak

OBJECTIVE

In the absence of standardized methods for Mycoplasma pneumoniae detection, we evaluated the diagnostic value of polymerase chain reaction (PCR) and IgM assays for detecting M. pneumoniae infection in children during a recent Korean outbreak.

METHODS

The diagnostic performances of PCR and IgM assays for M. pneumoniae in 1,109 clinical specimens were evaluated by the Japanese Respiratory Society (JRS) scoring system as an interim reference standard.

RESULTS

The level of agreement between both tests was fair. As analyzed by the JRS scoring system, the sensitivity of PCR was 45.2% in the group aged <5 years, 86.8% in the group aged 5 years to 10 years group, and 72.2% in the group aged 10 years to 18 years; the sensitivity of the IgM assay was 66.8%, 71.4%, and 55.6% in each group, respectively.

CONCLUSION

The sensitivity of PCR is relatively low but is superior to that of IgM assays such that diagnostic performance can be improved by both test methods in patients aged <5 years.

Periodic Genotype Shifts in Clinically Prevalent Mycoplasma pneumoniae Strains in Japan

Nationwide increases in Mycoplasma pneumoniae pneumonia cases in Japan were reported in 2011, 2012, 2015, and 2016. In this study, we isolated 554 M. pneumoniae strains in 4 areas in Japan (Kanagawa, Okayama, Osaka, and Saitama) between 2006 and 2019, and performed genotyping analysis. More than 80% of the strains isolated in 2011 and 2012 harbored type 1 p1 adhesin gene; however, strains harboring type 2 or its variant p1 gene increased in 2015 and 2016 and dominated after 2017. These findings suggested that a shift in the prevalent genotype of M. pneumoniae clinical strains occurred recently in Japan. More than 90% of the type 1 strains isolated after 2010 harbored macrolide-resistance mutations in their 23S rRNA gene, whereas most type 2 lineage strains had no such mutations. Consequently, the increase in type 2 lineage strains in Japan has reduced the macrolide resistance rate of clinical M. pneumoniae strains. During this analysis, we also identified M. pneumoniae strains carrying a novel variant type 1 p1 gene, and we classified it as type 1b. We then sequenced the genomes of 81 selected M. pneumoniae strains that we collected between 1976 and 2017 in Japan, and compared them with 156 M. pneumoniae genomes deposited in public databases to provide insights into the interpretation of M. pneumoniae genotyping methods, including p1 typing, multiple-locus variable-number tandem repeat analysis (MLVA), multi-locus sequence typing (MLST), and typing by 8 single-nucleotide polymorphism markers (SNP-8). As expected, p1 typing, MLST, and SNP-8 results exhibited good correlation with whole-genome SNP analysis results in terms of phylogenetic relationships; however, MLVA typing results were less comparable to those of the other methods. MLVA may be useful for the discrimination of strains derived from a single outbreak within a limited area; however, is not reliable for classification of strains collected from distantly separated areas at different time points. This study showed the usefulness of genome-based comparison of M. pneumoniae for molecular epidemiology. Genome sequencing of more strains will improve our understanding of global propagation routes of this pathogen and evolutionary aspects of M. pneumoniae strains.

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.

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.

Genetic diversity and macrolide resistance of Mycoplasma pneumoniae isolates from two consecutive epidemics in Slovenia

Two nationwide Mycoplasma pneumoniae epidemics occurred in Slovenia between 2006 and 2016. The aim of this study was to assess which M. pneumoniae genotypes were present in our area during the selected timeframe, whether the origin of the epidemics was monoclonal or polyclonal and whether the proportion between detected genotypes changed over time. We were also interested in the presence of macrolide resistance (MR) and whether it could be linked to specific genotypes. We performed pyrosequencing of the P1 gene and multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) typing from 872 M. pneumoniae isolates obtained from respiratory tract infections (RTI)-suffering patients. Additionally, isolates were tested for the presence of MR implicated mutations in the 23S rRNA gene. The MLVA typing results revealed that three main genotypes, MLVA-3,5,6,2, MLVA-3,6,6,2 and MLVA-4,5,7,2, were constantly present and occasionally joined by less abundant, short-lived genotypes, which were detected mostly, but not exclusively, during epidemics. We also noticed a switch in abundance from MLVA-3,5,6,2 and MLVA-3,6,6,2, which dominated in the first epidemic (77.0%; 97/126), to MLVA-4,5,7,2 (71.6%; 428/598), which dominated in the second. Similar to this finding, the dominant P1 type also shifted from type 2 to type 1, although a complete P1 type shift was not observed, since both types remained in circulation. MR was detected in 0.8% (7/872) of M. pneumoniae isolates. Our results seem to suggest that MR remains sporadic in Slovenia at this point in time and that both recent epidemics were polyclonal in nature and, possibly, to some extent, fuelled by the P1 type dominance change.

Association of the ACE, GSTM1, IL-6, NOS3, and CYP1A1 polymorphisms with susceptibility of mycoplasma pneumoniae pneumonia in Chinese children

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia (CAP) and the clinical presentation of mycoplasma pneumoniae pneumonia (MPP) varies widely. Genetic variability affecting the host response may also influence the susceptibility to MPP. Several studies have investigated the association between single nucleotide polymorphism (SNP) of some genes and the risks of CAP; however, the results were inconsistent. Here, we investigated the association of 5 functional genes and the risks of MPP, including ACE (rs4340), GSTM1 (Ins/del), IL-6 (rs1800795), NOS3 (rs1799983), and CYP1A1 (rs2606345) in a total of 715 subjects (415 cases, 300 controls) by using tetra-primer allele-specific polymerase chain reaction (PCR) and Sanger sequencing. The gene-gene interactions were analyzed using the Multifactor Dimensionality Reduction and cumulative genetic risk score approaches. Our results showed that 3 SNPs of ACE rs4340, IL-6 rs1800795, and NOS3 rs1799983 were significantly associated with the risks of MPP, while no differences were observed in genotype frequencies of GSTM1 (Ins/del) and CYP1A1 rs2606345 between both groups. The combinations of ACE rs4340D/NOS3 rs1799983T/CYP1A1 rs2606345G and ACE rs4340D/NOS3 rs1799983T contribute to the genetic susceptibility of MPP in Chinese children.

Analysis of clinical value of CT in the diagnosis of pediatric pneumonia and mycoplasma pneumonia

Pneumonia is an infectious disease of the lung causing mortality. Mycoplasma pneumonia (MP) is an atypical bacterial pneumonia that damages several organs. Lung computed tomography (CT) has been utilized in its identification. The aim of the present study was to examine the value of computed tomography diagnosis for pediatric MP. The present study prospectively analyzed the clinical and imaging data of 1,280 cases of pediatric MP in the out- and inpatient departments from March, 2010 to March, 2014; analyzed the morphology and distribution of the pneumonic lesion in the lungs; and summarized the value of CT diagnosis for pediatric MP. In the included children, there were 688 cases of lesions in the unilateral lobe, 592 cases of lesions in the bilateral lobes, 1,101 cases of extensive patchy opacity, 496 cases of mottled opacity, 432 cases of increased lung marking, 256 cases of streak opacity, 192 cases of ground-glass opacity, 992 cases of thickened bronchial wall in the lesions, 128 cases of lymphadenopathy in the hilar lymph nodes and mediastinal lymph nodes, and the lung CT showed 32 cases of pulmonary cavity and 144 cases of pleural effusion. In conclusion, the CT signals of pediatric MP had several types with some children exhibiting complicated changes. The child's clinical manifestation and symptoms should thus be considered in the diagnosis to improve the diagnostic rate.