Mycoplasma pneumoniae infection and macrolide resistance of children hospitalized in Ningbo Area， Zhejiang Province in 2019‒2021 / 上海预防医学

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.

Advances in Medical Treatment of Primary Aldosteronism / 中国医学科学杂志(英文版)

Primary aldosteronism (PA) is the most common form of secondary hypertension, with its main manifestations including hypertension and hypokalemia. Early identification of PA is extremely important as PA patients can easily develop cardiovascular complications such as atrial fibrillation, stroke, and myocardial infarction. The past decade has witnessed the rapid advances in the genetics of PA, which has shed new light on PA treatment. While surgery is the first choice for unilateral diseases, bilateral lesions can be treated with mineralocorticoid receptor antagonists (MRAs). The next-generation non-steroidal MRAs are under investigations. New medications including calcium channel blockers, macrophage antibiotics, and aldosterone synthase inhibitors have provided a new perspective for the medical treatment of PA.

Implementación de un método molecular para la identificación de Mycoplasma pneumoniae resistente a macrólidos / Implementation of a molecular method for the detection of macrolide-resistant Mycoplasma pneumoniae

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.

Epidemiological characteristics and macrolide-resistance of children hospitalized with Mycoplasma pneumo-niae infection in Beijing from 2016 to 2019 / 中华实用儿科临床杂志

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.

Advances in biodegradation of macrolide antibiotics / 生物工程学报

Macrolide antibiotics are a class of broad-spectrum antibiotics with the macrolide as core nucleus. Recently, antibiotic pollution has become an important environmental problem due to the irregular production and abuse of macrolide antibiotics. Microbial degradation is one of the most effective methods to deal with antibiotic pollution. This review summarizes the current status of environmental pollution caused by macrolide antibiotics, the degradation strains, the degradation enzymes, the degradation pathways and the microbial processes for degrading macrolide antibiotics. Moreover, the critical challenges on the biodegradation of macrolide antibiotics were also discussed.

Ureaplasma urealyticum infection and neonatal diseases / 中华实用儿科临床杂志

Ureaplasma urealyticum (UU) is an opportunistic pathogenic microorganism, widely colonized in the reproductive tract of women in childbearing age, and can cause fetal infection through vertical transmission.UU infections in neonates can cause damages to multiple systems, such as pneumonia, bronchopulmonary dysplasia, necroti-zing enterocolitis, intracranial hemorrhage, meningitis, and retinopathy of prematurity.Therefore, it is of important signi-ficance to avoid serious consequences in the neonatal period and improve long-term adverse outcomes by understan-ding the biological characteristics and epidemiological characteristics of UU and the neonatal diseases associated with UU infections, attaching great importance to the early screening and early intervention of UU infections and grasping the optimal treatment opportunity.

Non-antibacterial effects of macrolides and the application in the treatment of bronchiectasis / 国际儿科学杂志

Macrolide antibiotics have corresponding non-antibacterial effects in inhibiting inflammatory response, reducing airway mucus secretion, and reducing pathogen load.Bronchiectasis seriously affects the quality of life and growth of children.Currently, there is no specific treatment for bronchiectasis.Infection, chronic airway inflammation, and impaired mucociliary clearance are involved in the development of bronchiectasis.The non-antibacterial effects of macrolides in the treatment of cystic fibrosis, non-cystic fibrosis related bronchiectasis, and primary ciliary dyskinesia are reviewed in order to provide reference for pediatricians in clinical practice.

Progress of molecular epidemiology of mycoplasma pneumoniae in children / 国际儿科学杂志

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.

Advances in metabolic engineering of macrolide antibiotics / 生物工程学报

14- to 16-membered macrolide antibiotics (MA) are clinically important anti-infective drugs. With the rapid emergence of bacterial resistance, there is an urgent need to develop novel MA to counter drug-resistant bacteria. The targeted optimization of MA can be guided by analyzing the interaction between the MA and its ribosomal targets, and the desired MA derivatives can be obtained efficiently when combining with the rapidly developed metabolic engineering approaches. In the past 30 years, metabolic engineering approaches have shown great advantages in engineering the biosynthesis of MA to create new derivatives and to improve their production. These metabolic engineering approaches include modification of the structural domains of the polyketide synthase (PKS) and post-PKS modification enzymes as well as combinatorial biosynthesis. In addition, the R&D (including the evaluation of its antimicrobial activities and the optimization through metabolic engineering) of carrimycin, a new 16-membered macrolide drug, are described in details in this review.

Macrolide resistance, molecular characteristics and PFGE types of Bordetella pertussis strains / 中华微生物学和免疫学杂志

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.

Preparation and application of thermosensitive and repairable molecularly imprinted solid phase microextraction fiber / 中国药科大学学报

@#In this study,thermosensitive and repairable molecularly imprinted solid-phase microextraction fibers were synthesized using spiramycin as template molecule,methacrylic acid and N-isopropylacrylamide as functional monomers,ethylene glycol dimethacrylate as crosslinking agent,and silanized quartz capillary as carrier. The prepared molecularly imprinted solid-phase microextraction fibers were characterized by scanning electron microscope and nitrogen adsorption/desorption,and various parameters affecting the extraction efficiency were optimized. Due to high selectivity and sensitivity of the fibers for macrolide antibiotics,the quantitative analysis of four macrolide antibiotics in food matrix,spiramycin,tilmicosin,tylosin,and josamycin,was peroformed in combination with high performance liquid chromatography. In the range of 0.5 to 50 μg/mL,the chromatographic peak area showed a good linear relationship with the concentration. The spike recoveries of the samples at three different addition levels were between 81.8% and 119.1%;the inter-day precisions were less than 13.8% (n=6),and the intra-day precisions were less than 15.5% (n=3).

Macrolide antibiotics protects against ischemia-reperfusion injury after liver transplantation in rats / 中国组织工程研究

BACKGROUND: Liver transplantation is the standard treatment for end-stage liver disease and liver failure. However, ischemia-reperfusion injury can reduce the success rate of liver transplantation. When a limited number of liver donors are available for transplantation, how to reduce liver ischemia-reperfusion injury has become the primary issue in liver transplantation. OBJECTIVE: To evaluate the effect of macrolide antibiotics on ischemia-reperfusion injury after liver transplantation in rats. METHODS: Rat autologous orthotopic liver transplantation model was constructed. Wistar rats were randomly divided into macrolide antibiotics group and control group. In the macrolide antibiotics group, the donor liver was treated with macrolide antibiotics (60 mg/kg roxithromycin, 20 mg/kg clarithromycin and 40 mg/kg erythromycin) 30 minutes before hepatectomy, and the above macrolide antibiotic mixture was injected into the portal vein immediately after orthotopic liver transplantation. In the control group, rats were pretreated with the same volume of saline for 30 minutes before hepatectomy, and the same volume of saline was injected into the portal vein immediately after orthotopic liver transplantation. The survival rate of the rats was observed within 7 days after liver transplantation. The serum aspartate aminotransferase and alanine aminotransferase activities were detected by automatic biochemical analyzer at 48 and 72 hours after liver transplantation. Hematoxylin-eosin staining and immunohistochemistry assay were used to detect the morphological changes of liver tissues and the number of Ki-67 positive cells in liver transplantation rats. TUNEL and western blot assay were used to detect the number of apoptotic hepatocytes and the expression of caspase-3 and cleaved caspase-3 proteins in liver transplantation rats, respectively. The Kupffer cell number changes and levels of interleukin-6, interleukin-1β, and tumor necrosis factor-α in rat liver tissues after liver transplantation were detected by immunofluorescence and ELISA, respectively. RESULTS AND CONCLUSION: Macrolide antibiotics increased the overall survival rate of liver transplanted rats, improved the dysfunction of transplanted liver, reduced the severity of ischemia-reperfusion injury after liver transplantation, increased the regenerative capacity of transplanted liver, reduced the number of apoptotic cells and the ratio of cleaved caspase-3/caspase-3 in the transplanted liver tissue, and decreased the number of Kupffer cells and the levels of interleukin-6, interleukin-1β and tumor necrosis factor-α in the transplanted liver. All the results indicate that macrolide antibiotics protect against ischemia-reperfusion injury in rats undergoing liver transplantation.

Epidemiological characteristics, genotypes, genetic relationships and macrolide resistance of 31 Bor-detella pertussis strains isolated from infants and young children in Shenzhen / 中华微生物学和免疫学杂志

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.

Research progress in the structural modification of ketolides / 药学学报

Macrolide antibiotics have been widely utilized in the treatment of bacterial infections due to their strengths, low toxicity, and high efficacy. Because of the widespread application of macrolide drugs, the emergence of antibacterial resistance against antibiotics has become prominent. Ketolides, as the third generation macrolides, display improvement in activities against macrolide-resistant pathogens with broad antibacterial spectrum. Due to hepatotoxicity, the use of telithromycin has been limited. It is urgent to identify the novel sources of ketolides. So the structural modification of ketolides become the main research field of macrolide. This review introduces the recent progress in the structural modification of ketolide, with the purpose of providing support to development of new ketolide antibiotics.

Preliminary Study on Drug Susceptibility Profile and Resistance Mechanisms to Macrolides of Clinical Isolates of Non-tuberculous Mycobacteria from China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Macrolide susceptibility and drug resistance mechanisms of clinical non-tuberculous mycobacteria (NTM) isolates were preliminarily investigated for more accurate diagnosis and treatment of the infection in China.</p><p><b>METHODS</b>Four macrolides, including clarithromycin (CLAR), azithromycin (AZM), roxithromycin (ROX), and erythromycin (ERY), were used to test the drug susceptibility of 310 clinical NTM isolates from six provinces of China with the broth microdilution method. Two resistance mechanisms, 23S rRNA and erm, were analyzed with nucleotide sequence analysis.</p><p><b>RESULTS</b>Varied effectiveness of macrolides and species-specific resistance patterns were observed. Most Mycobacterium abscessus subsp. massiliense were susceptible and all M. fortuitum were highly resistant to macrolides. All the drugs, except for erythromycin, exhibited excellent activities against slow-growing mycobacteria, and drug resistance rates were below 22.2%. Only four highly resistant strains harbored 2,058/2,059 substitutions on rrl and none of other mutations were related to macrolide resistance. G2191A and T2221C on rrl were specific for the M. abscessus complex (MABC). Seven sites, G2140A, G2210C, C2217G, T2238C, T2322C, T2404C, and A2406G, were specifically carried by M. avium and M. intracellulare. Three sites, A2192G, T2358G, and A2636G, were observed only in M. fortuitum and one site G2152A was specific for M. gordonae. The genes erm(39) and erm(41) were detected in M. fortuitum and M. abscessus and inducible resistance was observed in relevant sequevar.</p><p><b>CONCLUSION</b>The susceptibility profile of macrolides against NTM was demonstrated. The well-known macrolide resistance mechanisms, 23S rRNA and erm, failed to account for all resistant NTM isolates, and further studies are warranted to investigate macrolide resistance mechanisms in various NTM species.</p>

Progresses of treatment of children with severe /refractory mycoplasma pneumoniae pneumonia / 国际儿科学杂志

Mycoplasma pneumoniae is a common pathogen leading to pediatdc respiratory infection,which belongs to self-limited disease and has a great response to macrolide antibiotics.In recent years,the morbidity of pediatric severe/refractory mycoplasma pneumoniae pneumonia has been increasing.Some of the patients suffer sequelae,even die.This disease seriously threatens the health of children.This review will introduce the treatment of mycoplasma pneumoniae pneumonia including general therapy,antibiotics,immunosuppressor,fiber bronchoscope and traditional Chinese medicine.

Related factors for and changes in clinical manifestations in mycoplasma pneumonia nonresponsive to macrolide treatment

PURPOSE: Mycoplasma pneumonia is known to be a major cause of community-acquired pneumonia in children. Macrolide has been the first-line treatment for mycoplasma pneumonia, but recently there has been an increasing tendency of macrolide-resistant Mycoplasma pneumoniae (MRMP). Therefore, this study aimed to investigate the clinical tendency and the therapeutic responsibility of mycoplasma pneumonia in terms of the fever duration after treatment and its associated factors. METHODS: A total of 346 children admitted with mycoplasma pneumonia during 3 recent periods (2008–2009, 2011–2012, and 2015–2016) were investigated with clinical manifestations, laboratory test results and chest x-ray findings. Patients were grouped according to fever duration and analyzed for differences in clinical features. RESULTS: There was no statistically significant difference in age or sex between the 3 periods (P=0.284 and P=0.559, respectively). Total fever duration during mycoplasma pneumonia was increased with time (P for trend < 0.001). The patients with a longer fever duration (≥3 days) after macrolide treatment presented with a higher CRP (P < 0.001) and with lobar-type pneumonia (P=0.020) compared to those with a shorter fever duration. Fever duration after steroid treatment became longer in the longer fever group in 2011 (P=0.015) and 2015 (P < 0.001), but not in 2008 (P=0.536). CONCLUSION: This study showed that the therapeutic effect of macrolide or steroid for mycoplasma pneumonia is recently attenuating and that high CRP, lobar-type pneumonia and presence of pleural effusion were the associated factors. Therefore, efforts to decrease MRMP and to develop better treatment guidelines for mycoplasma pneumonia are needed in the future.

Relationship between macrolide resistance mutations in Mycoplasma pneumoniae and its genotype / 中华微生物学和免疫学杂志

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.

Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry Analysis of 16 Kinds of Residual Antibiotics in Chicken Manure / 分析化学

A sensitive and effective method for determination of 16 kinds of antibiotics, including tetracycline, sulfonamide, fluoroquinolone and macrolide, in livestock and poultry manure using solid phase extraction-ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established.Aiming at the chemical properties and sample impurities of the target, the parameters such as mass spectrum conditions, types of extraction and ultrasonic power were optimized.Finally, the samples were extracted with 50% acetonitrile in phosphate buffer solution (pH =4) for three times, followed by ultrasonic steaming, centrifugal and rotary, dilution, and purified by SAX-HLB.After sample loading, the solid phase was washed with 10 mL of methanol-acetone (80∶20, V/V), evaporated to near dryness at 35℃, and then re-dissolved and vortex mixed in 1 mL of 0.1% formic acid∶methanol (1∶1, V/V).The extracts were analyzed with UPLC-MS/MS and calculated by external standard method based on the monitored product ion.The results indicated that the average spiked recoveries of tetracycline, sulfonamide, fluoroquinolone and macrolide in manure were 56.4%-94.6% with relative standard deviations (RSDs) of 2.6%-19.8%, the LODs (S/N=3) were 0.01-2.50 μg/kg, and the LOQs (S/N=10) were 0.05-7.90 μg/kg.The method was simple with high stability, high sensitivity and good reproducibility, and suitable for the simultaneously determination of many antibiotics in animal and poultry manure.

Prevalence and molecular characteristics of Mycoplasma pneumoniae in Beijing in the first half of 2015 and 2016 / 中华微生物学和免疫学杂志

Objective To investigate the prevalence and molecular characteristics of Mycoplasma pneumoniae (M.pneumoniae) in Beijing in the first half of 2015 and 2016. Methods Respiratory tract specimens were collected from children with respiratory infection who were admitted to Affiliated Children′s Hospital of Capital Institute of Pediatrics in the first half of 2015 and 2016. DNA molecules were extracted from these specimens and then analyzed by real-time PCR to detect M.pneumoniae repMp1 genes. Speci-mens that were positive for M.pneumoniae were genotyped by modified MLVA[multiple-locus variable-num-ber tandem-repeat (VNTR) analysis] and P1-RFLP (restriction fragment length polymorphism analysis). Moreover, macrolide resistance was evaluated through detecting mutations in 23S rRNA genes. Results The prevalence of M.pneumoniae from January to June in 2015 and 2016 was 18.5% (50/271) and 35% (99/283),respectively. Of the 50 strains isolated in 2015,48 were M4-5-7-2/P1 genotype and only two were M3-5-6-2/P2 genotype. The 99 strains isolated in 2016 belonged to three genotypes, including 82 of M4-5-7-2/P1,two of M4-5-7-3/P1 and 15 of M3-5-6-2/P2. Macrolide resistance rate was 92% in 2015 and 83.8% in 2016. Conclusion More cases of M.pneumoniae infection were detected in the first half of 2016 than in the corresponding period of 2015. Compared with the 2015,the proportion of M4-5-7-2/P1 genotype strains decreased,while that of M3-5-6-2/P2 genotype strains increased in 2016. Moreover, a decline in macrolide resistance rate was found in 2016.