ABSTRACT
ObjectiveTo investigate Mycoplasma pneumoniae （MP） infection and macrolide resistance of hospitalized children in Ningbo Area in 2019‒2021. MethodsA total of 6 782 respiratory throat swab specimens were collected from hospitalized pediatric patients with pneumoniae， admitted in Ningbo Women and Children's Hospital from January， 2019 to December 2021. MP and its mutations in 23S rRNA were detected by real-time polymerase chain reaction. ResultsAmong 6 782 respiratory throat swab specimens from 2019‒2021， 1 290 cases （19.02%） were MP positive， and the positive rate decreased year by year （P<0.05）. The positive rate in 2019 was 28.12%， higher than that in 2020 （7.16%） and 2021 （5.16%） （all P<0.017）. The mutation of 23S rRNA occurred in 947 cases， with a mutation rate of 73.41%. The mutation rate in 2020 was 84.04%， higher than that in 2019 （73.01%） and 2021 （66.23%）. The differences of positive rate and mutation rate in different seasons were significant （P<0.05） （all P<0.008）. The positive rate was the highest in summer （25.00%）， and the mutation rate was the highest in winter （78.89%）. The positive rate of female children was 20.52%， higher than that of male children （17.82%） （P<0.05）， and the mutation rates of female and male children were 74.93% and 71.77% （P>0.05）， respectively. The difference of positive rate among the different age was significant （P<0.05）. The positive rates in the 5‒ and 8‒ years groups were 27.24% and 26.38%， higher than those in the 1‒ and 2‒ years groups， respectively. The difference of mutation rate among the four groups in age was not significant （P>0.05）. ConclusionThe infection rate of MP in children decreases in Ningbo Area from 2019 to 2021. MP infection may be related with gender， seasonal distribution， age， and the resistance rate of MP to macrolide is high.
ABSTRACT
Introducción: Mycoplasma pneumoniae es causa frecuente de infecciones respiratorias en niños y jóvenes. Los macrólidos son la primera línea de tratamiento. La rápida emergencia de resistencia a estos antimicrobianos ha motivado el desarrollo de métodos moleculares para su detección en muestras clínicas positivas a este patógeno. Objetivo: Implementar un método de reacción en cadena de la polimerasa en tiempo real (RT-PCR) para la detección de resistencia a macrólidos a partir de muestras clínicas positivas a M. pneumoniae. Métodos: Se implementó una RT-PCR para la detección de las mutaciones A2058G y A2059G en el ARNr 23S de M. pneumoniae. Se analizaron 24 muestras clínicas positivas a M. pneumoniae, que provenían de pacientes con síntomas respiratorios. Se evaluó la sensibilidad, especificidad, repetibilidad y reproducibilidad de la RT-PCR. Resultados: La RT-PCR mostró un 100 % de especificidad para M. pneumoniae y un 92 % de sensibilidad, con un límite de detección de 2 copias/µL, que equivale a 10 copias/reacción. Además, se demostró la reproducibilidad y repetibilidad de estos resultados. Se obtuvo una correcta identificación de los genotipos salvaje y mutante, correspondientes a cada control. De las muestras clínicas positivas a M. pneumoniae, el 77,3 % (17/22) se identificó como sensible a macrólidos y el 22,7 % (5/22) como resistente. Conclusiones: La alta sensibilidad y especificidad del método de RT-PCR implementado permite que el Laboratorio Nacional de Referencia de Micoplasmas del Instituto de Medicina Tropical Pedro Kourí cuente con un método eficaz para el diagnóstico de M. pneumoniae resistente a macrólidos.
Introduction: Mycoplasma pneumoniae is a common cause of respiratory track infections in children and young adults. Macrolides are the first-line treatment. The rapid emergence of resistance to these antimicrobials has motivated the development of molecular methods for their detection in clinical samples positive for this pathogen. Objective: To implement a real-time polymerase chain reaction (RT-PCR) method for the detection of macrolide resistance in M. pneumoniae positive clinical samples. Methods: An RT-PCR was implemented to detect mutations A2058G and A2059G in 23S rRNA of M. pneumoniae. M. pneumoniae positive clinical samples from 24 patients with respiratory symptoms were analyzed. Sensitivity, specificity, repeatability and reproducibility of the RT-PCR assays were evaluated. Results: The RT-PCR assays showed 100% specificity to M. pneumoniae, and 92% sensitivity with a detection limit of 2 copies/µL, equivalent to 10 copies/reaction. Moreover, the repeatability and reproducibility of these results were demonstrated. Wild and mutant genotypes associated to each control were properly identified. Of the clinical samples positive for M. pneumoniae, 77.3% (17/22) were macrolide-sensitive and 22.7% (5/22) were macrolide-resistant. Conclusions: The high sensitivity and specificity of the RT-PCR method implemented provides the National Reference Laboratory of Mycoplasmas of the Institute of Tropical Medicine Pedro Kourí with an effective method for the diagnosis of macrolide-resistant M. pneumoniae.
Subject(s)
HumansABSTRACT
Objective:To investigate epidemiological characteristics and macrolide-resistance of hospitalized children with Mycoplasma pneumoniae (MP) infections in Beijing from 2016 to 2019, so as to provide basis for the prevention and treatment of pediatric Mycoplasma pneumoniae pneumonia (MPP).Methods:The clinical data were analyzed retrospectively from 8 691 children hospitalized with community acquired pneumonia in Beijing Children′s Hospital between January 2016 and September 2019.MP RNA was detected by simultaneous amplification and testing (SAT), and macrolide resistance of MP was examined by MP and macrolide-resistant isolate diagnostic kit (PCR with fluorescence probes). Chi- square test was used for categorical analysis. Results:Among 8 691 cases detected by SAT, the overall detection rate of MP was 28.10% (2 442/8 691 cases). The detection rates of MP from 2016 to 2019 were 26.23%, 31.36%, 27.84 % and 26.57%, respectively.The detection rate of MP in 2017 was significantly higher than that in other years ( χ2=16.11, P<0.05). The detection rate of MP in females was 29.65%(1 107/3 733 cases), which was evidently higher than that in males 26.93%(1 335/4 958 cases) ( χ2=7.85, P<0.05). The positive rates of MP in summer[32.21% (726/2 254 cases)] and autumn[39.76%(852/2 143 cases)] were significantly higher than those in spring[17.00% (327/1 924 cases)] and winter[22.66%(537/2 370 cases)] ( χ2=315.15, P<0.001). The percentages of MP were 35.06%(732/2 088 cases) in preschoolers and 37.71%(1 160/3 076 cases) in school-age children, which were significantly higher than 11.20%(232/2 072 cases) in infants and 22.01% (318/1 445 cases) in toddlers ( χ2=509.89, P<0.001). Macrolide resistance detection was conducted in 1 524 patients by fluorescent PCR.Among them, 1 386 patients were positive for drug resistance, and the positive rate was 90.94%.The prevalence of macrolide-resistant MP from 2016 to 2019 were 88.19%, 90.93%, 90.56% and 92.90%, respectively.Macrolide-resistant rates were not related with gender, age and season. Conclusions:MP can be detected in all seasons, but most prevalently in summer and autumn.Girls are more prone to MP infections than boys.The detection rate of MP increases with age, and the positive rate is higher in preschoolers and school-age children.During the 4-year study period, the drug resistant rate of MP remain high.
ABSTRACT
【Objective】 To compare the macrolide resistance, molecular characteristics and multilocus antigen sequence typing (MAST) of Bordetella pertussis (Bp) collected from Xi’an and Shanghai so as to provide reference for prevention of pertussis and optimize vaccination strategies. 【Methods】 Erythromycin, azithromycin and clarithromycin susceptibility of clinical isolates collected from Xi’an and Shanghai during 2018 and 2019 were determined by E-test. PCR was used to detect the drug-resistant genes and mutation sites. MAST was employed to do molecular typing for the strains. The differences in macrolide resistance and MAST types between Xi’an and Shanghai were compared. 【Results】 Totally 34 strains from Xi’an and 26 strains from Shanghai were isolated. There were differences between Xi’an and Shanghai in the macrolide resistance (χ2=13.650, P<0.001). The composition ratio of MAST types of pertussis strains was also different between Xi’an and Shanghai (χ2=18.642, P<0.001) in that the prn1/ptxP1/ptxA1/fim3-1/fim2-1 strains dominated in Xi’an, while the prn1/ptxP1/ptxA1/fim3-1/fim2-1 and prn2/ptxP3/ptxA1/fim3-1/fim2-1 were almost half and half in Shanghai. A2047G site mutation was detected in all the macrolide-resistant strains, but not in all sensitive strains. Methylase genes ermA and ermB were detected in some macrolide-resistant strains. No other macrolide-resistant genes were found in resistant strains and no mutation or drug resistance gene was found in all the susceptible strains. 【Conclusion】 Differences existed between Xi’an and Shanghai in the macrolide resistance and MAST types of Bordetella pertussis strains. Further monitoring of Bordetella pertussis in China is required to better understand the resistance and evolution of the pathogen.
ABSTRACT
Mycoplasma pneumoniae(MP)is the main pathogen causing community-acquired pneumonia in children, usually treated with macrolide drugs.The type of MP genes is mainly based on PCR-RFLP(P1-restriction fragment length polymorphism analysis)and MLVA(multiple locus variable number tandem repeat analysis)typing methods.During epidemics, MP subtypes will undergo certain transformation.Studying and mastering the prevalence characteristics and transformation laws of MP subtypes can deeper understand the distribution area, prevalence year and clinical relevance of each subtype of MP.Due to the extensive use of antibiotics, the resistance of mycoplasma pneumoniae to macrolides has increased , which has become a global public health concern.Studies have shown that MP resistance is related to mutations in the V region of 23S rRNA gene domain.The improvement of typing technology also guides significance for the rational selection of antibiotics.It is imperative to carry out systematic and comprehensive molecular epidemiological studies of MP genotypes and its resistance mutations, and reveal the distribution characteristics, epidemic trends and resistance mutations of MP subtypes at the molecular level.This paper reviews the research progress of molecular epidemiology of mycoplasma pneumoniae in children, and provides ideas for the monitoring, prevention and clinical treatment of MP infection.
ABSTRACT
Objective:To analysis the macrolide resistance, molecular characteristics and plused-field gel electrophoresis(PFGE) type of Bordetella pertussis ( Bp), explore the possible resistance mechanism and the relationship between PFGE types and macrolide resistance profiles. Methods:Erythromycin, azithromycin and clarithromycin susceptibility of clinical isolates during 2016 to 2018 was determined by E-test. PCR was used to detect the drug-resistant genes and mutation sites. PFGE were employed to do molecular typing for the strains.Results:Thirty-five strains were isolated, of which 27 strains were resistant to all three antibiotics, two strains were resistant to erythromycin and azithromycin, and six strains were sensitive to all three antibiotics. Partial macrolide resistant strains carried the methylase gene ermA (27.6%, 8/29) and ermB (31.0%, 9/29); A2047G site mutation was detected in macrolide-resistant strains, while no drug-resistant genes or mutation sites were found in sensitive strains. Resistant strains were classified into BPSR23 and BPFINR9 types, while sensitive strains were other profiles. Conclusions:The clinical isolated Bp were seriously resistant to erythromy and showed signs of resistance to other macrolides. The acquisition of methylase gene and mutation of A2047G site might be the main mechanism of resistance. The macrolide resistance might have has a certain correlation with PFGE profile.
ABSTRACT
Objective To understand the epidemiological characteristics, genomic variations and macrolide resistance of Bordetella pertussis ( B. pertussis) strains circulating in Shenzhen with clinical data analysis, genotype profiling, phylogenetic analysis and antimicrobial susceptibility test. Methods Clinical data of patients with pertussis in Shenzhen Children's Hospital were collected from the electronic medical re-cord system. Genome sequences of 31 B. pertussis isolates were analyzed with next-generation sequencing and de novo assembled. Multilocus sequence typing (MLST) was performed to identify their sequences types. Sequence alignment by BLASTn was used to identify virulence genotypes and mutations in 23S rRNA gene. A phylogenetic tree was constructed to analyze the relationships among them. E-test was used to identify ma-crolide resistance. Results All of the 31 B. pertussis strains were identified as sequence type-2 (ST-2) by MLST with diverse virulence genotypes. Two were prn-deficient strains. Based on the phylogenetic tree, all of the isolates were distant from vaccine strains. Nineteen isolates were resistant to erythromycin with A2047G mutation in 23S rRNA. Conclusions The virulence genotypes of B. pertussis strains in Shenzhen were diverse with increasing non-vaccine genotypes. Macrolide-resistant strains were prevalent. This study might provide reference for improving the prevention, management and vaccination strategy of pertussis.
ABSTRACT
Objective To analyze the relationship between macrolide resistance mutations in My-coplasma pneumoniae (Mp) and its genotype by multiple-locus variable-number tandem-repeat analysis (MLVA). Methods One hundred and forty-three Mp-positive specimens were collected in Beijing(54 col-lected at the Affiliated Children′s Hospital of the Capital Institute of Pediatrics),the United States(59 col-lected at four different geographical locations:Kansas City,Missouri;Seattle,Washington;New York,New York;Chicago,Illinois) and Australia(30 provided by the diagnostic laboratory at the Centre for Infectious Diseases and Microbiology Laboratory Services,Institute of Clinical Pathology and Medical Research,West-mead Hospital,Sydney). Nested PCR was used to detect mutations in 23S rRNA. A capillary electrophore-sis-based single tube multiplex PCR (mPCR-CE) was used to analyze the MLVA types of Mp in those sam-ples. Results A2063G mutation was identified in 57 specimens including 49 from Beijing,seven from the United States and one from Australia. The 143 Mp-positive specimens were typed into 10 distinct MLVA types. Fifty-four specimens collected in Beijing belonged to four MLVA types, which were M4-5-7-2 (44/54,81.5%),M3-5-6-2 (7/54,13.0%), M4-5-6-2 (2/54,3.70%) and M4-5-5-2 (1/54,1.85%). Fifty-nine specimens collected in the United States belonged to six MLVA types including M4-5-7-2(27/59, 45.8%),M3-5-6-2 (18/59,30.5%),M3-6-6-2 (11/59,18.6%),M3-5-6-1 (1/59,1.69%),M4-5-7-3 (1/59,1.69%) and M5-5-7-2 (1/59,1.69%). Thirty specimens of Mp from Australia were grouped to five types with M3-5-6-2 (12/30, 40.0%) and M4-5-7-2 (10/30, 33.3%) and M3-5-7-2 (5/30, 16.7%) being the predominant types. Macrolide resistance mutations were detected in 57 out of 143 speci-mens (49 from Beijing,seven from the United States and one from Sydney) and 50 of them were MLVA type of M4-5-7-2. Conclusion The MLVA type of M4-5-7-2 is associated with macrolide resistance in Mp.