Although the decreased susceptibility of gonococci to penicillin and tetracycline is a worldwide problem in the treatment of gonorrhea, the gonococci in the West Pacific region are particulary notorious in their resistance. Using a plate dilution method, susceptibility of the gonococci isolated at this institution during 1970 to 1975 was tested to penicillin and tetracycline, which are the most widely used antibiotics for the treatment of gonorrhea. The data of this susceptibility, together with that of the strains isolated during 1966 to 1969 from prostitutes, were analyzed and herewith reported. The range of minimum inhibitory concentration (MIC) of penicillin was 0.01 to 2.0U/ml. Among the 191strains, 87.9% required MIC of 1.0U/ml and over, and 29.3% required 1.0U/ ml and over. The range of MIC of tetracycline was from 0.125 to over 2 microgram/ml. Among the 120 strains, 60% required MIC of 1 microgram/ml and over. This in vitro evidence indicates wide prevalence of less susceptible strains which are difficult to cure with conventional doses of penicillin or with tetracycline. Comparison of the degree and the frequency of less susceptible strains by the year of isolation showed some variation, which may however have been induced by the difference of sources, rather than by the difference of time of isolation.
Neisseria gonorrhoeae/drug effects* ; Penicillins/pharmacology* ; Tetracyclines/pharmacology*

OBJECTIVEImpact of the presence of bacteria associated with a marine dinoflagellate, Alexandrium tamarense CI01, on the growth and toxin production of the algae in batch culture was investigated.

METHODSPronounced changes in the activities of the algal culture were observed when the culture was treated with different doses of a mixture of penicillin and streptomycin.

RESULTSIn the presence of antibiotics at the initial concentration of 100 u/mL in culture medium, both algal growth and toxin yield increased markedly. When the concentration of antibiotics was increased to 500 u/mL, the microalgal growth was inhibited, but resumed in a few days to eventually reach the same level of growth and toxin production as at the lower dose of the antibiotics. When the antibiotics were present at a concentration of 1 000 u/mL, the algal growth was inhibited permanently.

CONCLUSIONSThe results indicate that antibiotics can enhance algal growth and toxin production not only through their inhibition of the growth and hence competition for nutrients, but also through their effects on the physiology of the algae.

Animals ; Anti-Bacterial Agents ; pharmacology ; Bacteria ; Dinoflagellida ; microbiology ; pathogenicity ; Eutrophication ; Marine Toxins ; biosynthesis ; Penicillins ; pharmacology ; Saxitoxin ; Streptomycin ; pharmacology

BACKGROUND: Few studies have evaluated the performance of the recently introduced MicroScan Synergies plus Positive Combo 3 Panels (SIPC3) (Dade Behring Inc., USA). We evaluated the clinical efficacy of the panels in identification (ID) and antimicrobial susceptibility testing (AST) of Staphylococcusaureus and enterococci. METHODS: To evaluate the panels' accuracy of identification, the results obtained using the test panels were compared with those obtained by using conventional biochemical tests in conjunction with VITEK 2 system (bio-Merieux, USA). In addition, the AST results obtained using the panels were compared with those obtained by performing CLSI broth microdilution. RESULTS: The overall agreement between the approaches for the ID of S. aureus and enterococci was 100% and 96%, respectively. The categorical and essential agreements (CA and EA) for S. aureus were 98%, each. Very major errors (VME), major errors (ME), and minor error (mE) for S. aureus were 0.45%, 0.3%, and 4.2%, respectively. The majority of VMEs were for oxacillin (8.6%), penicillin (2.0%), erythromycin (7.9%), clindamycin (3.8%), and tetracycline (4.1%). For enterococci, the CA, EA, VME, ME, and mE were 88.8%, 93.7%, 4.4%, 0%, and 2.8%, respectively. The 80.5% (29/36) of Enterococcus faecium had concordant ID with the reference. Most of the categorical errors (3 VMEs and 14 mEs) were observed for quinupristin/dalfopristin (Synercid; Catalytica Pharmaceuticals Inc., USA). CONCLUSIONS: The panels compared favorably with conventional methods for the ID and AST of S. aureus. However, we expected a better performance for ID of E. faecium and AST using Synercid.
Anti-Bacterial Agents/*pharmacology ; Clindamycin/pharmacology ; Drug Resistance, Bacterial ; Enterococcus/*drug effects/isolation & purification ; Erythromycin/pharmacology ; Microbial Sensitivity Tests/instrumentation/*methods ; Oxacillin/pharmacology ; Penicillins/pharmacology ; Reagent Kits, Diagnostic ; Staphylococcus aureus/*drug effects/isolation & purification ; Tetracycline/pharmacology

BACKGROUND: Viridans group streptococci (VGS) are both commensal microbes and potential pathogens. Increasing resistance to penicillin in VGS is an ongoing issue in the clinical environment. We investigated the difference in susceptibility and resistance to penicillin among various VGS species. METHODS: In total 1,448 VGS isolated from various clinical specimens were analyzed over a two-yr period. Identification and antimicrobial susceptibility test was performed by the automated VITEK 2 system (bioMerieux, France) or the MicroScan MICroSTREP system (Siemens, Germany). RESULTS: Among the 1,448 isolates, 412 were isolated from blood (28.4%). Streptococcus mitis group was the most frequently isolated (589 isolates, 40.7%), followed by the S. anginosus group (290 isolates, 20.0%), S. sanguinis group (179 isolates, 12.4%) and S. salivarius group (57 isolates, 3.9%). In total, 314 isolates could not be identified up to the species level. The overall non-susceptibility to penicillin was observed to be 40.0% (resistant, 11.2% and intermediately resistant, 28.8%) with uneven distribution among groups; 40.2% in S. sanguinis group (resistant, 5.0% and intermediately resistant, 35.2%), 60.3% in S. mitis group (resistant, 20.9% and intermediately resistant, 39.4%), 78.9% in S. salivarius group (resistant, 8.8% and intermediately resistant, 70.1%), and 6.2% in S. anginosus group (resistant, 1.7% and intermediately resistant, 4.5%). CONCLUSIONS: Antimicrobial resistance patterns towards penicillin show differences among various VGS; this should be considered while devising an effective antimicrobial treatment against VGS.
Anti-Infective Agents/*pharmacology ; Body Fluids/microbiology ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Penicillins/pharmacology ; Streptococcal Infections/microbiology/pathology ; Viridans Streptococci/*drug effects/isolation & purification

OBJECTIVETo investigate the susceptibility of Streptococcus mutans (S. mutans) biofilms to antimicrobial agent by confocal laser scanning microscopy (CLSM).

METHODSS. mutans biofilms formed in vitro on glass slice were acted on with penicillin of different concentrations for 3 h. Then these biofilms were stained by fluorescence and were observed by CLSM. The bacterial density and viability of biofilms were recorded.

RESULTSWhen S. mutans biofilms were exposed to penicillin of 2 500 mg/L for 3 h, it was not completely killed. The higher the concentration of penicillin was, the weaker the biofilms against penicillin.

CONCLUSIONSCompared with planktonic S. mutans, S. mutans biofilms produced stronger resistance to penicillin. It suggests that we should find new strategies to control the infection caused by biofilm in clinic.

Anti-Infective Agents ; administration & dosage ; pharmacology ; Biofilms ; drug effects ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Penicillins ; administration & dosage ; pharmacology ; Streptococcus mutans ; drug effects

The study was aimed to investigate the influence of penicillin and streptomycin on proliferation, apoptosis and extracellular secretion (ECS) produced from human umbilical cord derived mesenchymal stem cells (MSC). MSC were isolated from umbilical cord tissue, then the immunotyping, multipotent differentiation and proliferation of these cells were assayed by cytometry, cytochemistry and MTT respectively. The expressions of ECS and apoptosis-related genes (bcl-2, bax) were detected by quantitative RT-PCR. The results showed that the phenotype of these cells matched with the characteristics of MSC. Penicillin and streptomycin of low concentrations promoted MSC proliferation, with the most effective concentration of 100 U/ml. Expressions of ECS cultured in addition of penicillin and streptomycin were down-regulated. Furthermore, apoptosis-related factor (bcl-2/bax) expression levels in low concentrations penicillin and streptomycin groups were higher than that in the control group. It is concluded that low concentrations penicillin and streptomycin can promote the proliferation and reduce the apoptotic rate, but high dose can inhibit the ECS component expression of MSC.
Cell Differentiation ; Cells, Cultured ; Extracellular Matrix ; secretion ; Flow Cytometry ; Gene Expression Regulation ; Humans ; Mesenchymal Stromal Cells ; cytology ; drug effects ; secretion ; Penicillins ; pharmacology ; Streptomycin ; pharmacology ; Umbilical Cord ; cytology

Changes in udder health and antibiotic resistance of mastitis pathogens isolated from dairies upon conversion from conventional to organic management over a 3-year period was studied. Coagulase-negative staphylococci (CNS) were the most prevalent mastitis pathogens isolated. CNS were significantly less resistant to beta-lactam antibiotics when isolated from milk after the herd transitioned to organic management. Cessation of the use of antimicrobial therapies in dairies in combination with organic management could lead to a reduction in the antimicrobial resistance of mastitis pathogens.
Ampicillin/pharmacology ; Animals ; Anti-Bacterial Agents/pharmacology ; Cattle ; Cephalothin/pharmacology ; Cloxacillin/pharmacology ; Drug Resistance, Microbial ; Female ; Lactation ; Mastitis, Bovine/*microbiology ; Microbial Sensitivity Tests ; Organic Agriculture ; Penicillins/pharmacology ; Prevalence ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus/*drug effects/*isolation & purification

BACKGROUNDIncreasing prevalence of Staphylococcus aureus (S. aureus), particularly methicillin-resistant S. aureus (MRSA) has been reported in China. In this study, we investigated the drug resistance characteristic, genetic background, and molecular epidemiological characteristic of S. aureus in Changsha.

METHODSBetween January 2006 and December 2008, 293 clinical isolates of S. aureus were collected from 11 hospitals in Changsha and identified by the Vitek-2 system. All the isolates were verified as MRSA by PCR amplification of both femA and mecA genes. K-B disk method was used to test drug sensitivity of S. aureus to antibiotics. Pulsed-field gel electrophoresis (PFGE) was performed for genotypic and homologous analysis of 115 isolates randomly selected from the original 293 clinical S. aureus isolates.

RESULTSS. aureus was highly resistant to penicillin, ampicillin, erythromycin, and clindamycin with resistant rates of 96.6%, 96.6%, 77.1%, and 67.2% respectively. All the isolates were susceptible to tecoplanin, vancomycin, and linezolid. MRSA accounted for 64.8% (190/293) of all the S. aureus strains. The 115 S. aureus isolates were clustered into 39 PFGE types by PFGE typing, with 13 predominant patterns (designated types A to M) accounting for 89 isolates. The most prevalent PFGE type was type A (n = 56, 48.7%) and 100.0% of type A strains were MRSA. PFGE type A included 13 subtypes, and the most prevalent subtype was subtype A1 (46.4%, 26/56). Strains with PFGE type A were isolated from eight hospitals (8/11), and both subtypes A1 and A4 strains were isolated in a university hospital.

CONCLUSIONSClinical isolates of S. aureus in Changsha were resistant to multiple traditional antibiotics. There was an outbreak of PFGE type A MRSA in this area and the A1 subtype was the predominant epidemic clone. Dissemination of the same clone was an important reason for the wide spread of MRSA.

Ampicillin ; pharmacology ; Anti-Bacterial Agents ; pharmacology ; China ; Clindamycin ; pharmacology ; Electrophoresis, Gel, Pulsed-Field ; Erythromycin ; pharmacology ; Humans ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; genetics ; Microbial Sensitivity Tests ; Penicillins ; pharmacology ; Staphylococcus aureus ; drug effects ; genetics ; Vancomycin ; metabolism

Aerococcus viridans, a catalase-negative gram-positive coccus rarely causing bacteremia, was isolated from blood cultures of a 52-yr-old man under the gran-ulocytopenic condition. The isolate showed the typical characteristics of A. viridans, i.e., tetrad arrangements in gram stain, positive pyrrolidonyl aminopeptidase (PYR) and negative leucine aminopeptidase (LAP) reactions, and no growth at 45 degrees C.The isolate was revealed to be highly resistant to penicillin, erythromycin, clindamycin, and ceftriaxone, although most strains of A. viridans isolated from the previously reported patients were susceptible to penicillin and other commonly used antibiotics. Even though A. viridans is rarely associated with human infections, it could be a potential causative agent of bacteremia, especially in immunocompromised patients.
Agranulocytosis/*complications/microbiology/physiopathology ; Bacteremia/*complications/microbiology/physiopathology ; Ceftriaxone/pharmacology ; Clindamycin/pharmacology ; *Drug Resistance, Multiple, Bacterial ; Erythromycin/pharmacology ; Gram-Positive Bacterial Infections/*complications/microbiology/physiopathology ; Humans ; Male ; Middle Aged ; Penicillins/*pharmacology ; Streptococcaceae/*drug effects/isolation & purification

Animals ; Flunarizine ; pharmacology ; Hippocampus ; drug effects ; physiopathology ; Male ; Neurons ; drug effects ; physiology ; Penicillins ; adverse effects ; Rats ; Rats, Wistar ; Seizures ; chemically induced ; physiopathology