OBJECTIVEMacrolide 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.

METHODSFour 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.

RESULTSVaried 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.

CONCLUSIONThe 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.

Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; metabolism ; China ; Drug Resistance, Bacterial ; Gene Expression Regulation, Bacterial ; Humans ; Macrolides ; pharmacology ; Mycobacterium ; drug effects ; genetics ; Polymorphism, Genetic

OBJECTIVEMutations in 23S rRNA gene are known to be associated with macrolide resistance in Mycoplasma pneumoniae (M. pneumoniae). However, these mutations alone do not fully explain the high resistance rates in Asia. The aim of this study was to investigate other possible mutations involved in macrolide resistance in M. pneumoniae.

METHODSThe whole genomes of 10 clinical isolates of M. pneumoniae with macrolide resistance were sequenced by Illumina HiSeq2000 platform. The role of the macrolide-specific efflux transporter was assessed by efflux-pump inhibition assays with reserpine and carbonyl cyanide m-chlorophenyl-hydrazone (CCCP).

RESULTSA total of 56 single nucleotide polymorphisms (SNPs) were identified in 10 clinical isolates in comparison to the reference strains M129 and FH. Strikingly, 4 of 30 SNPs causing non-synonymous mutations were clustered in macrolide-specific efflux system gene macB encoding macrolide-specific efflux pump protein of the ATP-binding cassette transporter family. In assays of the minimal inhibitory concentrations (MIC) of macrolide antibiotics in the presence of the efflux pump inhibitors caused a significant decrease of MICs, even under detectable levels in some strains.

CONCLUSIONOur study suggests that macrolide efflux pump may contribute to macrolide resistance in M. pneumoniae in addition to the common point mutations in 23S rRNA gene.

Anti-Bacterial Agents ; pharmacology ; Drug Resistance, Bacterial ; genetics ; Genome-Wide Association Study ; Macrolides ; pharmacology ; Microbial Sensitivity Tests ; Mutation ; Mycoplasma pneumoniae ; drug effects ; genetics

Bovine aortic endothelial cells (BAECs) were cultured with high glucose (33 mmol/L), 4 mg/L green tea polyphenols (GTPs) or 4 mg/L GTPs co-treatment with high glucose for 24 h in the presence or absence of Bafilomycin-A1 (BAF). We observed that high glucose increased the accumulation of LC3-II. Treatment with BAF did not further increase the accumulation of LC3-II. Results also showed an increased level of p62 and decreased Beclin-1. However, GTPs showed inversed trends of those proteins. Furthermore, GTPs co-treatment with high glucose decreased the level of LC3-II and a much higher accumulation of LC3-II was observed in the presence of BAF in comparison with high glucose alone. Results also showed a decreased p62 and increased Beclin-1. The results demonstrated that GTPs alleviated autophagy inhibition induced by high glucose, which may be involved in the endothelial protective effects of green tea against hyperglycemia.
Animals ; Autophagy ; drug effects ; Cattle ; Cells, Cultured ; Endothelial Cells ; drug effects ; metabolism ; Gene Expression Regulation ; drug effects ; Glucose ; toxicity ; Macrolides ; pharmacology ; Polyphenols ; chemistry ; pharmacology ; Tea ; chemistry

OBJECTIVETo investigate the effect of bafilomycin A1 (BAF) on the cell proliferation, invasiveness, apoptosis, and oxaliplatin sensitivity in gastric cancer MGC-803 cells.

METHODSMGC-803 cells were divided into control group, BAF group, oxaliplatin group, and BAFµ oxaliplatin group. MTT assay and plate clone formation assay were used to assess the viability and colony forming ability of the cells after the treatments. The expression of nucleosomes in the cells was examined with ELISA. The cell migration and invasion after the treatments were evaluated. Western blotting was performed to detect the expression of Bcl-2 and Bax in the treated cells, and scanning electron microscopy, immunohistochemistry and Western blotting were employed to to observe the cell autophagy.

RESULTSCompared with the control cells, the cells treated with BAF showed a substantial decrease in autophagosome accumulation with attenuated cell proliferation, migration and invasion. Compared with cells treated with oxaliplatin alone, the cells treated with both BAF and oxaliplatin showed significantly lowered autophagosome accumulation, suppressed cell proliferation, migration and invasion, increased cell apoptosis, increased Bax expression and lowered Bcl-2 expression.

CONCLUSIONBAF can inhibit the proliferation and invasiveness of MGC-803 cells, promote cell apoptosis by inhibiting autophagy, and enhances the sensitivity of the cells to oxaliplatin.

Apoptosis ; Autophagy ; Cell Line, Tumor ; drug effects ; Cell Movement ; Cell Proliferation ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; Macrolides ; pharmacology ; Organoplatinum Compounds ; pharmacology ; Stomach Neoplasms ; pathology

AIM: To discover anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) microbial natural products or their derivatives. METHOD: Azalomycin F5a (1) was prepared through fermentation of Streptomyces hygroscopicus var. azalomyceticus, and its derivatives were synthesized through hydrocarbylation in hydrocarbyl alcoholic-AcOH (4 : 1) and subsequent demalonylation with 2 mol·L(-1) KOH in MeOH-H2O (7 : 3). Their activities against MRSA ATCC 33592 and three clinical MRSA isolates were evaluated by the agar diffusion and broth microdilution methods. RESULTS: Four demalonylazalomycin F5a derivatives 2 to 5 were synthesized. The anti-MRSA activity assay indicated that compounds 1 to 5 showed remarkable activity against MRSA, and their minimum inhibitory concentrations (MICs) were respectively 3.0-4.0, 0.5-1.0, 0.67-1.0, 0.67-0.83, and 0.5-0.83 μg·mL(-1). CONCLUSION Azalomycin F5a and the demalonylazalomycin F5a derivatives 2-5 showed remarkable anti-MRSA activity, and the anti-MRSA activities of 2 to 5 were higher than that of 1, while the anti-MRSA activities of 2 to 5 showed no obvious differences. It was also shown that the malonyl monoester group of azalomycin F5a was less important for its anti-MRSA activity.
Anti-Bacterial Agents ; chemistry ; pharmacology ; Humans ; Macrolides ; chemistry ; pharmacology ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Staphylococcal Infections ; microbiology ; Structure-Activity Relationship

We describe 2 cases of pneumonia caused by the same macrolide-resistant Mycoplasma pneumoniae in siblings. M. pneumoniae was identified using real-time PCR. Direct sequence analysis of the 23S rRNA gene revealed a point mutation in V domain (A2063G) of the 23S rRNA gene.
Anti-Bacterial Agents/pharmacology ; Child ; Child, Preschool ; Drug Resistance, Bacterial/drug effects ; Humans ; Macrolides/pharmacology ; Male ; Mutation ; Mycoplasma pneumoniae/*genetics/isolation & purification ; Pneumonia, Mycoplasma/*diagnosis/microbiology/radiography ; RNA, Ribosomal, 23S/*analysis ; Real-Time Polymerase Chain Reaction ; Sequence Analysis, RNA ; Siblings

BACKGROUND: This study aimed to evaluate the prevalence of Mycoplasma pneumoniae in primary and tertiary care hospitals and its macrolide resistance rate. METHODS: Nasopharyngeal swabs were collected from 195 pediatric patients in primary and tertiary care hospitals from October to November 2010. The AccuPower MP real-time PCR kit (Bioneer, Korea) was used for the detection of M. pneumoniae. Direct amplicon sequencing was performed to detect point mutations conferring resistance to macrolides in the 23S rRNA gene. RESULTS: Among the 195 specimens, 17 (8.7%) were M. pneumoniae positive, and 3 of the strains (17.6%) obtained from these 17 specimens displayed the A2063G mutation in 23S rRNA. Three macrolide-resistant M. pneumoniae isolates were isolated from patients hospitalized at the primary care hospital. The positive rates of M. pneumoniae for the primary and tertiary care hospitals were 12.1% (15/124) and 2.8% (2/71), respectively (P=0.033). CONCLUSIONS: The positive rate of M. pneumoniae in the primary care hospital was higher than that in the tertiary care hospital. Simultaneous detection of M. pneumoniae and macrolide-resistant mutation genes in the 23S rRNA by real-time PCR is needed for rapid diagnosis and therapy of M. pneumoniae infections.
Anti-Bacterial Agents/*pharmacology ; Child, Preschool ; Drug Resistance, Bacterial/*drug effects ; Female ; Humans ; Infant ; Infant, Newborn ; Macrolides/*pharmacology ; Male ; Mycoplasma pneumoniae/genetics/*isolation & purification ; Nasopharynx/microbiology ; Pneumonia, Mycoplasma/epidemiology/microbiology ; Primary Health Care ; RNA, Ribosomal, 23S/analysis ; Reagent Kits, Diagnostic ; Real-Time Polymerase Chain Reaction ; Tertiary Healthcare

This study was purpose to investigate the role of reactive oxygen species (ROS) in apoptosis and autophagy induced by FTY720 in multiple myeloma cell line U266. U266 cells were treated by different concentrations of FTY720 for 24 h, the apoptotic rates were detected by flow cytometry, and the expression of LC3B was detected by Western blot. The results indicated that apoptosis and autophagy were induced by FTY720 in U266 cells. Autophagy induced by FTY720 could lead to cell death. Bafilomycin A1, the inhibitor of autophagy, could enhance the cell viability in U266 cells treated with FTY720. NAC or Tiron, ROS scavenger, could decrease the FTY720 induced apoptosis and the expression of LC3B-II was reduced in combination of FTY720 with NAC or Tiron as compared with treatment with FTY720 only. It is concluded that FTY720 can induce U266 cell apoptosis and autophagy. ROS is the mediator that regulates both the apoptosis and autophagy in multiple myeloma cells.
1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt ; Apoptosis ; drug effects ; Autophagy ; drug effects ; Cell Line, Tumor ; Fingolimod Hydrochloride ; Humans ; Macrolides ; Microtubule-Associated Proteins ; metabolism ; Multiple Myeloma ; metabolism ; pathology ; Propylene Glycols ; pharmacology ; Reactive Oxygen Species ; metabolism ; Sphingosine ; analogs & derivatives ; pharmacology

BACKGROUNDMycoplasma pneumoniae is a common pathogen that caused community-acquired pneumonia (CAP). P1 protein served as major adhesion and immunodominant protein in Mycoplasma pneumoniae, but little about P1 gene was learned and the relationship between P1 genotype and macrolide resistance has yet to be explored.

METHODSThe DNA sequence of the entire P1 gene from 35 strains isolated from clinical specimens collected in Beijing, China, in 2010 was determined. The resulting sequences were checked for known macrolide resistance mutations, such as A2063G, A2064G, C2617G in domain V of 23S rRNA. Antibiotic susceptibility test was done to further identify macrolide resistant strains.

RESULTSThirty-four clinical strains were type 1, and were identical to type 1 reference strain MP129. Only one clinical strain, MpYYM22, was type 2, and proved to be variant 2c. One synonymous point mutation in the P1 type 1 gene from two isolates was identified relative to the MP129 P1 sequence at nucleotide position (nt) 552 (C>A), while another two isolates had missense mutations at nt 2504 (G>A). This point mutation caused an amino acid change from glycine to glutamic acid. An AGT tri-nucleotide variable-number tandem repeat (VNTR), coding for serine and repeating 6-11 times, up to 15-16 times, was found in the region between the RepMP4 and RepMP2/3 elements in the 35 isolates examined. All 35 clinical strains, including MpYYM22, demonstrated macrolide resistance with the range of minimum inhibitory concentration (MIC) of erythromycin from 64 to 256 µg/ml, having an A2063G transition in domain V of the 23S rRNA gene.

CONCLUSIONSP1 type 1 was the dominant type of Mycoplasma pneumoniae in Beijing in 2010, although variant 2c strains were present. More samples are needed to determine whether there is a relationship between the P1 genotype and macrolide resistance, as the 35 strains examined did not allow a conclusive result. However, the AGT tri-nucleotide VNTR may be a more informative locus for multi-locus VNTR analysis.

Anti-Bacterial Agents ; pharmacology ; DNA, Bacterial ; Drug Resistance, Bacterial ; Genotype ; Humans ; Macrolides ; pharmacology ; Microbial Sensitivity Tests ; Mycoplasma pneumoniae ; drug effects ; genetics ; metabolism

OBJECTIVETo investigate the genetic features of drug resistance to group A streptococcus(GAS) and macrolides antibiotics among pediatric patients in Beijing 2012.

METHODSA total of 199 strains of GAS were collected from 36 hospitals in Beijing between May and July, 2012. All strains were isolated from oropharyngeal swabs. The minimum inhibitory concentrations (MICs) of ten antibiotics (penicillin, ampicillin, erythromycin, clindamycin, tetracycline, levofloxacin, tigecycline, vancomycin, linezolid and streptogramin) were detected by VITEK-2 compact with GPS-67 test kit. The genes encoding macrolides resistance (ermA, ermB and mefA ) were amplified and tested by PCR. The macrolides resistant phenotype of group A streptococcus was detected by double disc test (D-test).

RESULTSAmong 199 strains of GAS collected in this study, 101(50.8%) were from suburbs and the other 98(49.2%) were from urban areas. 111(55.8%) strains were collected from scarlet fever patients while the other 88(44.2%) were from oropharyngeal infection cases. All the strains were sensitive to penicillin and ampicillin, and the percentage of resistance to erythromycin, clindamycin and tetracycline were 96.5% (192/199), 95.5% (190/199) and 92.0% (183/199), respectively. All strains were susceptible to levofloxacin, tigecycline, vancomycin, linezolid and streptogramin. The rates of resistance to erythromycin, clindamycin and tetracycline were different in different districts, however, the difference in it between ages and clinical diagnosis did not show statistical significance (P > 0.05) . The detected rate of drug resistance gene ermB was 98.5% (196/199). The gene ermA was only detected out in 5 strains and the gene mefA was not detected out. 199 strains showed A macrolides resistant phenotype cMLS, while the phenotype iMLS was not found in this study.

CONCLUSIONThis study demonstrates the high level of clindamycin resistance in group A streptococcus collected from children in Beijing, 2012. The macrolides resistance of group A streptococcus was highly prevalent in Beijing, and the dominant phenotype was cMLS mediated by gene ermB.

Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Child ; Child, Preschool ; China ; epidemiology ; Drug Resistance, Multiple, Bacterial ; genetics ; Genotype ; Humans ; Macrolides ; pharmacology ; Streptococcal Infections ; epidemiology ; microbiology ; Streptococcus pyogenes ; drug effects ; genetics ; isolation & purification