Mycoplasma pneumoniae in Korean children: The epidemiology of pneumonia over an 18-year period

Epidemiological characteristics and meteorological factors of childhood Mycoplasma pneumoniae pneumonia in Hangzhou

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen of pediatric respiratory infections and the relation of M. pneumoniae pneumonia (MPP) with meteorological factors remains obscure. This study aims to investigate the epidemiological characteristics of childhood MPP and observe if there is a relationship between epidemiological characteristics and meteorological factors in Hangzhou.

METHODS

M. pneumoniae DNA in nasopharyngeal aspirates of hospitalized pneumonia children were detected by polymerase chain reaction from January 1, 2007 to December 31, 2009. The positive rates of MPP (MPP rates) in different years, seasons and ages were compared. The relationship between MPP rates and meteorological data, including mean air temperature (°C), mean relative humidity (%), monthly precipitation (mm) and raining days were analyzed.

RESULTS

In 14 799 pneumonia cases found from 2007 to 2009, the MPP rate was 18.5%. Altogether 1610 boys (16.9%) and 1134 girls (21.4%) suffered from MPP with a significant difference between both genders (χ(2)=45.68, P<0.001). In children younger than 1 year, 1-2 years, 3-6 years, and older than 7 years, the MPP rates were 9.8%, 21.1%, 44.4% and 61.6%, respectively. The MPP rates were significantly higher in older children than in younger ones (trends test χ(2)=46.72, P<0.001). In a descending order, the MPP rates in summer, autumn, spring, and winter were 27.8%, 23.9%, 18.0% and 11.6%, respectively (χ(2)=372.75, P<0.001). The MPP rates in 2007 to 2009 were 12.9%, 19.3% and 23.6%, respectively (trends test χ(2)=13.72, P<0.001). Of the four meteorological factors, only monthly mean air temperature was included in the multiple linear regression model (P<0.001).

CONCLUSIONS

This study showed that the MPP rate was higher in older children than in younger ones. Girls had a higher positive rate of MPP than boys. In Hangzhou, MPP was more prevalent in summer and autumn. Air temperature was the only meteorological factor affecting the prevalence of MPP.

Subtypes and variants ofMycoplasma pneumoniae: local and temporal changes in Germany 2003–2006 and absence of a correlation between the genotype in the respiratory tract and the occurrence of genotype-specific antibodies in the sera of infected patients

Mycoplasma pneumoniaeis a frequent cause of community-acquired pneumonia. Three subtypes and three variants ofM. pneumoniaehave been described showing sequence differences in the main P1 adhesin. Between 2003 and 2006 we collected respiratory tract samples of adult outpatients with symptoms of pneumonia in a German nationwide network and detectedM. pneumoniaeby real-time PCR in 140 specimens. The strains were typed by sequencing and demonstrated the circulation of subtypes 1 and 2 and variants 2a and 2b. The overall number of isolates belonging to the two variant genotypes increased during the investigation period but the relationship of subtypes and variants within the participating local centres varied strongly. ELISA experiments using sera of acute-phase patients with a knownM. pneumoniaetype in the respiratory tract resulted in no correlation of IgA and IgG antibodies to subtype- and variant-specific regions of theP1gene with the genotype of theM. pneumoniaestrain causing the actual infection.

Macrolide-resistant Mycoplasma pneumoniae: characteristics of isolates and clinical aspects of community-acquired pneumonia

Mycoplasma pneumoniae is one of the main pathogens causing community-acquired respiratory tract infections in children and adults. Macrolide (ML) antibiotics are recognized generally as first-choice agents for M. pneumoniae infections, and these antibiotics were thought to have excellent effectiveness against M. pneumoniae for many years. In 2000, however, M. pneumoniae showing resistance to macrolides was isolated from clinical samples obtained from Japanese pediatric patients with community-acquired pneumonia (CAP). Since then, prevalence of ML-resistant M. pneumoniae isolates in pediatric patients has increased rapidly. In 2007, ML-resistant M. pneumoniae isolates were obtained from Japanese adults with CAP; numbers of such isolates also have gradually increased in Japan. Recently, similar antimicrobial resistance in M. pneumoniae has begun to emerge worldwide. In this review, we focus on changes of ML-resistant M. pneumoniae from year to year and consider resistance mechanisms as well as clinical features of patients with resistant M. pneumoniae infection.

A case of acute hepatitis with Mycoplasma pneumoniae infection and transient depression of multiple coagulation factors

We report a case of acute severe hepatitis with Mycoplasma pneumoniae (M. pneumoniae) infection and transient depression of multiple coagulation factors. A 5-year-old boy, previously healthy, was admitted with pneumonia. M. pneumoniae infection was confirmed by serology testing. Liver enzymes were elevated on admission without any past medical history. After treatment with azithromycin for 3 days, pneumonia improved, but the hepatitis was acutely aggravated. Partial thromboplastin time (PTT) was prolonged and depression of multiple coagulation factors developed. Liver biopsy revealed features consistent with acute hepatitis. A week later, liver enzymes were nearly normalized spontaneously. Normalization of prolonged PTT and coagulation factors were also observed several months later. This may be the first case of transient depression of multiple coagulation factors associated with M. pneumoniae infection.

Comparison of commercial and in-house real-time PCR assays used for detection of Mycoplasma pneumoniae

We tested two commercial and three in-house PCR assays under standardized conditions to detect Mycoplasma pneumoniae. All five procedures were able to demonstrate M. pneumoniae DNA in a concentration comparable to 1 CFU/microl, but the mean crossing points resulted in differences in the concentration of the genome copies of a factor of 20.