PURPOSE: Erythromycin-resistant beta-hemolytic streptococci (BHS) has recently emerged and quickly spread between and within countries throughout the world. In this study, we evaluate the antimicrobial susceptibility patterns and erythromycin resistance mechanisms of BHS during 2003-2004. MATERIALS AND METHODS: The MICs of seven antimicrobials were determined for 204 clinical isolates of BHS from 2003 to 2004. Resistance mechanisms of erythromycin-resistant BHS were studied by the double disk test as well as by polymerase chain reaction (PCR). RESULTS: Compared with our previous study, resistance among Streptococcus pyogenes isolates to a variety of drugs decreased strikingly: from 25.7% to 4.8% in erythromycin; 15.8% to 0% in clindamycin; and 47.1% to 19.0% in tetracycline. The prevalent phenotypes and genotypes of macrolide-lincosamide-streptograminB (MLSB) resistance in Streptococcus pyogenes isolates have been changed from the constitutive MLSB phenotype carrying erm(B) to the M phenotype with mef(A) gene. In contrast with Streptococcus pyogenes, resistance rates to erythromycin (36.7%), clindamycin (43.1%), and tetracycline (95.4%) in Streptococcus agalactiae isolates did not show decreasing trends. Among the Streptococcus dysgalactiae subsp. equisimilis isolates (Lancefield group C, G), resistance rates to erythromycin, clindamycin, tetracycline and chloramphenicol were observed to be 9.4%, 3.1%, 68.8%, and 9.4%, respectively. CONCLUSION: Continual monitoring of antimicrobial resistance among large-colony-forming BHS is needed to provide the medical community with current data regarding the resistance mechanisms that are most common to their local or regional environments.
Anti-Bacterial Agents/*pharmacology ; Drug Resistance, Multiple, Bacterial ; Erythromycin/*pharmacology ; Genes, Bacterial ; Genotype ; Hospitals ; Humans ; Incidence ; Korea ; Microbial Sensitivity Tests ; Streptococcus/*drug effects/genetics/isolation & purification ; Streptococcus agalactiae/drug effects/genetics/isolation & purification ; Streptococcus pyogenes/drug effects/genetics/isolation & purification

Lysins are murein hydrolases produced by bacteriophage that act on the cell wall of host bacteria to release progeny phages. Research indicated that lysins could kill bacteria effectively and specifically in vitro. To prepare recombinant bacteriophage lysin of Streptococcus (PlyC) and analyze its biological activity, we obtained two genes of PlyC named PlyCA and PlyCB by PCR amplification and inserted them into pET-32a(+), then transformed the recombinant expression vectors pET-32a(+)-PlyCA and pET-32a(+)-PlyCB into E. coli BL21(DE3) respectively. After induction with 0.7 mmol/L IPTG at 30 degrees C for 7 h, PlyCA and PlyCB were successfully expressed, SDS-PAGE analysis determined that they all constituted above 30% of the total cell proteins. After Ni(2+)-NTA affinity chromatography, the purity was more than 95%. With the denaturation and protein refolding, we gained the recombinant PlyC. To determine its biological activity, we adopted turbidimetry and plate count method. Before and after lysin treatment, the cell morphology was studied by scanning electron microscopy (SEM). The results showed that the recombinant PlyC could specifically cleavage Streptococcus pyogenes (group A beta-hemolytic streptococci). Under the incubation time of 60 min with 4 microg/mL PlyC in Streptococcus pyogenes dilution which OD600 was 0.56, the germicidal effect was up to 99.6%, while SEM observations showed that cell wall cracked and presented cell debris. This finding laid the foundation for the further study and achieving an effective treatment for streptococcal infection.
Bacteriolysis ; Enzymes ; biosynthesis ; genetics ; isolation & purification ; Escherichia coli ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; isolation & purification ; Streptococcus pyogenes ; drug effects

BACKGROUND: In order to determine the clinical usefulness of the MicroScan (Siemens Healthcare Diagnostics, USA) MICroSTREP plus antimicrobial panel (MICroSTREP) for testing antimicrobial susceptibility of beta-hemolytic streptococci (BHS) and viridans group streptococci (VGS), we compared the accuracy of MICroSTREP with that of the CLSI reference method. METHODS: Seventy-five BHS and 59 VGS isolates were tested for antimicrobial susceptibility to ampicillin, penicillin, cefotaxime, meropenem, erythromycin, clindamycin, levofloxacin, and vancomycin by using MICroSTREP and the CLSI agar dilution method. RESULTS: The overall essential agreement with regard to minimum inhibitory concentrations (MICs) (within +/-1 double dilution) between MICroSTREP and the CLSI reference method was 98.2%, and categorical agreement (CA) was 96.9%. For the BHS isolates, the CA for erythromycin was 96.0%, whereas that for cefotaxime, meropenem, levofloxacin, and vancomycin (for ampicillin, penicillin, and clindamycin; 98.7%) was 100%. For the VGS isolates, the CA for penicillin was 84.7% and that for erythromycin, clindamycin, and vancomycin (for meropenem, 86.5%; for ampicillin, 88.1%; and for cefotaxime and levofloxacin, 96.6%) was 100%. All categorical errors of penicillin and ampicillin in the VGS isolates were minor. CONCLUSIONS: The accuracy of MICroSTREP is comparable to that of the CLSI reference method, suggesting that this panel can be effective for testing antimicrobial susceptibility of BHS and VGS.
Anti-Bacterial Agents/*pharmacology ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Reagent Kits, Diagnostic ; Streptococcal Infections/microbiology ; Streptococcus/*drug effects/isolation & purification ; Viridans Streptococci/*drug effects/isolation & purification

Bacteria ; drug effects ; isolation & purification ; Drug Resistance ; Escherichia coli ; drug effects ; Female ; Haemophilus influenzae ; drug effects ; Humans ; Klebsiella pneumoniae ; drug effects ; Male ; Microbial Sensitivity Tests ; Respiratory Tract Infections ; microbiology ; Staphylococcus aureus ; drug effects ; Streptococcus pneumoniae ; drug effects

BACKGROUND: With the emergence of antimicrobial resistance among Streptococcus pneumoniae, a more accurate and automated antimicrobial susceptibility testing method is essential. We evaluated the BD Phoenix Automated Microbiology System (Becton Dickinson Diagnostic Systems, USA) SMIC/ID-2 panel for antimicrobial susceptibility testing of S. pneumoniae. METHODS: A total of 113 clinical strains of S. pneumoniae (88 penicillin susceptible strains, 8 intermediate strains, and 17 resistant strains by 2008 CLSI criteria) were tested. Minimum inhibitory concentrations (MICs) for penicillin, cefotaxime, clindamycin, erythromycin, levofloxacin, trimethoprim/ sulfamethoxazole, tetracycline, and vancomycin were determined by Etest (AB Biodisk, Sweden) and Phoenix System. The results obtained by Phoenix system were compared to those obtained by Etest. RESULTS: The overall essential agreement of MICs (within one dilution of MICs) defined by the Phoenix and Etest was 92.3%. Neither very major errors nor major errors were produced, and minor errors were 6.5%. Minor errors were frequently observed in susceptibility testings for penicillin (22.1%), cefotaxime (12.4%), and trimethoprim/sulfamethoxazole (11.5%). CONCLUSIONS: The Phoenix SMIC/ID-2 panel provided a simple and rapid susceptibility testing for S. pneumoniae, and the results were in a good agreement with those of Etest. The Phoenix system appears to be an effective automated system in clinical microbiology laboratories.
Anti-Bacterial Agents/pharmacology ; Bacterial Typing Techniques/instrumentation/methods ; Drug Resistance, Bacterial ; Microbial Sensitivity Tests/*methods ; Reagent Kits, Diagnostic ; Streptococcus pneumoniae/*drug effects/growth & development/isolation & purification

OBJECTIVETo compare the antibacterial effect of Galla Chinensis with that of chlorhexidine by means of chemostat and provide experimental foundation for caries prevention with Chinese medicine instead of chemicals in future.

METHODA multispecies consortium biofilm (BF) model was construted in the chemostat. The growth-inhibition on bacterial biofilm coated on HA was investigated by means of the colony-forming units (CFU). Acid-inhibition was inspected by continual pH-recording in the flow cells. And the profile on the biofilm treated by both experimental medicines was observed with the scanning electromicroscopy (SEM).

RESULTBoth of the experimental medicines could inhibit the growth of the BF bacteria. And Galla Chinensis had no obvious influence on the ecological composing of the BF bacteria. Both of the experimental medicines could inhibit the acid producion of experimental bacteria. But the final pH of Galla Chinensis was lower than that of chlorhexidine. A typical biofilm formed on HA was observed by SEM. Both of Galla chinensis and chlorhexidine could inhibit the production of extracellular matrix and make the BF profile on the surface of the HA clearer and simpler.

CONCLUSIONGalla Chinensis had definite antibacterial effect. No obvious difference is found between Galla Chinensis (4 g x L(-1)) and chlorhexidine (0.5 g x L(-1)). Therefore, it is possible for Chinese medicine to gradually replace the chemical medicine in clinic and it will give a new choice for caries prevention.

Actinomyces ; drug effects ; growth & development ; Animals ; Anti-Bacterial Agents ; pharmacology ; Anti-Infective Agents, Local ; pharmacology ; Bacteria ; drug effects ; growth & development ; Biofilms ; drug effects ; growth & development ; Chlorhexidine ; pharmacology ; Hydrogen-Ion Concentration ; Insecta ; chemistry ; Materia Medica ; isolation & purification ; pharmacology ; Streptococcus mutans ; drug effects ; growth & development ; Streptococcus sanguis ; drug effects ; growth & development

OBJECTIVETo study antibacterial chemical constituents of Sarcandra glabra.

METHODThe constituents of the chloroform and EtOAc-soluble portions of the EtOH extract from the whole plant of S. glabra, which posses the antibacterial activities, were isolated and purified with column chromatography. The compounds were identified by physical and spectroscopic techniques.

RESULTSix compounds were isolated and identified as 4, 4'-biisofraxidin (1), esculetin (2), fraxetin (3), scoparone (4), isofraxidin (5), scopoletin(6), respectively.

CONCLUSIONCompound 1 is a novel natural product. Compounds 24 were isolated from the plants of Chloranthaceae for the first time. The antibacterial activities of these six compounds were tested for the first time. Some compounds may have potential for future study and development as plant-derived oral antibacterial agents.

Anti-Bacterial Agents ; analysis ; chemistry ; isolation & purification ; pharmacology ; Coumarins ; analysis ; isolation & purification ; pharmacology ; Drugs, Chinese Herbal ; chemistry ; Magnetic Resonance Spectroscopy ; Magnoliopsida ; chemistry ; Porphyromonas gingivalis ; drug effects ; Spectrometry, Mass, Electrospray Ionization ; Spectrophotometry, Infrared ; Streptococcus mutans ; drug effects

OBJECTIVE: To investigate the pathogenic bacteria distribution and drug susceptibility in children with acute otitis media (AOM) in different age and different season in the Pearl River Delta region. METHOD: Four hundred and forty-two children diagnosed as AOM were divided into three groups by age factor and four groups by season factor. Midge ear pus collecting and culturing were used for bacteria and antimicrobial susceptibility test. RESULT: (1) Strains of bacteria were isolated from 356 children with the positive rate of 80.5%. Streptococcus pneumoniae (39.2%), staphylococcus aureus (25.9%) and haemophilus influenzae (7.4%) were the most frequently isolated pathogens. (2) Streptococcus pneumoniae was the main pathogenic bacteria in 0-1 year group and > 1-3 years group (P < 0.05), staphylococcus aureus was the most frequently isolated pathogen in >3 years group (P < 0.05); (3) In the season groups, the number of children with AOM decreased significantly in July-September group. There was no significant difference of streptococcus pneumoniae distribution among the four groups (P > 0.05). Staphylococcus aureus was the main pathogen in January-March group (P < 0.05); (4) Drug sensitivity shown that linezolid and ofloxacin were most sensitive to streptococcus pneumoniae and staphylococcus aureus, and macrolides had a good therapy effect to haemophilus influenzae. CONCLUSION The pathogens distribution and drug susceptibility in children with AOM were varies in different age and different season. As a result, a treatment should be done based on the climate, environment, and pathogens distribution of a region.
Adolescent ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Haemophilus influenzae ; drug effects ; isolation & purification ; Humans ; Infant ; Male ; Microbial Sensitivity Tests ; Otitis Media ; drug therapy ; epidemiology ; microbiology ; Seasons ; Staphylococcus aureus ; drug effects ; isolation & purification ; Streptococcus pneumoniae ; drug effects ; isolation & purification

Three new alkyl substituted anthraquinone derivatives, trivially named as symploquinones A-C (Compounds 1-3) were isolated from Symplocos racemosa. The structures of these compounds were determined on the basis of extensive spectroscopic analyses (UV, IR, Mass, H- and C-NMR, and two-dimensional (2D) NMR techniques). The resulting data were also compared with the reported literature. These compounds were then subjected to antibacterial or antibiofilm testing. Compounds 1 and 3 exhibited good antibacterial activity in the concentration range of 160-83 μg·mL against Streptococcus mutans, methicillin resistant Staphylococcus aureus and Proteus mirabilis. Both compounds were further screened for anti-biofilm activity, which revealed promising activities at sub-MIC concentrations. None of the compounds were found to be active against Klebsiella pneumoniae.
Anthraquinones ; chemistry ; isolation & purification ; pharmacology ; Anti-Bacterial Agents ; chemistry ; isolation & purification ; pharmacology ; Biofilms ; drug effects ; growth & development ; Ericales ; chemistry ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; physiology ; Microbial Sensitivity Tests ; Proteus mirabilis ; drug effects ; physiology ; Spectrophotometry, Infrared ; Streptococcus mutans ; drug effects ; physiology

BACKGROUND: Group A streptococcus (GAS) is the most common cause of bacterial pharyngitis in children. Antibiotic resistance rates and emm genotypes of GAS isolated from patients with acute pharyngitis were studied in 2009. METHODS: Throat cultures were taken from 499 children with acute pharyngitis in Jinju, Korea, in 2008-2009. A total of 174 strains (34.9%) of GAS were isolated, and antimicrobial susceptibility testing was performed using the disk diffusion method. The phenotypes of macrolide resistance and macrolide resistance genes were determined. The emm genotypes were identified using PCR and sequencing. The data were compared with those acquired in 2002 in the same region. Data on the annual macrolide production were collected between 1999 and 2008. RESULTS: The resistance rates of GAS to erythromycin, clindamycin, and tetracycline were 4.6%, 2.9%, and 2.3%, respectively. The constitutive resistance rate was 62.5% for the erm(B) gene and 37.5% for the M phenotype of the mef(A) gene. emm4 was most frequently detected (28.2%), followed by emm89 (20.1%). Most of the erythromycin resistant strains had the emm28 genotype. We noted a gradual increase in macrolide production during the study period. CONCLUSIONS: The erythromycin resistance rate of GAS isolated from children with acute pharyngitis was significantly lower in 2009 (4.6%) than in 2002 (44.8%). We observed a remarkable change in the distribution of emm genotypes during the 7-yr period. The significant decline in erythromycin resistance in 2009 might be associated with a prominent decrease in the resistant genotype emm12 (3.4% in 2009 vs. 28.0% in 2002) rather than restriction of macrolide use.
Acute Disease ; Adolescent ; Anti-Bacterial Agents/*pharmacology ; Child ; Child, Preschool ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Bacterial/genetics ; Erythromycin/*pharmacology ; Female ; Genotype ; Humans ; Male ; Pharyngitis/drug therapy/*microbiology ; Phenotype ; Sequence Analysis, DNA ; Streptococcus pyogenes/*drug effects/*genetics/isolation & purification