[Research for the improvement of acylation conditions in antistaphylococcal penicillin synthesis]. / Cercetari privind îmbunatatirea conditiilor de acilare în cazul obtinerii penicilinelor antistafilococice.

AIM: The 6-aminopenicillanic acid acylation with certain acyl chlorides was performed in order to obtain antistaphylococcal penicillins with bigger crystals, easy to filtrate (shorter filtration time), much pure, and an increased output. MATERIAL AND METHODS: Oxacillin sodium salt was synthesized by acylating an aqueous solution of 6-aminopenicillanic acid sodium salt (NaHCO3 not in excess) with an ethylacetate solution of 5-phenyl-3-methyl-isoxazolyl-4-carboxilic acid chloride. The crystallization was performed with a 40.5% sodium 2-ethyl hexanoate izopropanolic solution. All tests (IR spectrum, iodometric titration, and microbiological dosage) were performed according to the Xth Romanian Pharmacopoeia standards. RESULTS: The amount of synthesized oxacillin was higher and the output of 88,21%. Oxacillin had a high chemical purity (98,72%), and a very good microbiological activity (95% of the standard activity). CONCLUSIONS: Oxacillin crystals were bigger, the filtration speed was increased, and process efficacy improved. The output of the process was also improved being higher than with classical acylation.

[Chromogenic medium for detection of enterobacteria producing beta-lactamases in North-Eastern Romania]. / Performantele unui mediu cromogen în detectarea enterobacteriilor producatoare de beta-lactamaze cu spectru extins din nord-estul României.

UNLABELLED: We evaluated the performances and analyzed practicability of an ESBL-detecting chromogenic agar medium (chromID ESBL, bioMerieux) for the screening of ESBL production. MATERIAL AND METHODS: We have tested 112 enterobacteria strains, isolated in 2009 year, in North Eastern region of Romania. Each bacterial strain was cultured on a prepared plate chromogenic medium and the results were recorded after incubation at 37 degrees C for 18 to 24 h or, if necessary, for 48 h. We calculated the sensitivities, specificities, and positive and negative predictive values for this medium, using as gold standard ceftzidime or cefotaxime and clavulanate combination disks on Iso-Sensitest agar. K. pneumoniae ATCC 700603 and E. coli ATCC 25922 were used as the positive and negative control for ESBL production, respectively. RESULTS: For all tested strains, the chromID ESBL agar showed a high sensitivity (97%), but a low specificity (66%). The positive and negative predictive values were 98% and 57%, respectively. The chromID ESBL had false-positive results for 2 confirmed ESBL-positive strains. CONCLUSION: The very good sensitivity of the chromID ESBL agar ESBL detection represent a convenient method for the recovery and identification of ESBL-producing enterobacteria.

[Research regarding extended-spectrum beta-lactamases produced by enterobacteria strains]. / Cercetari privind producerea de beta-lactamaze cu spectru extins la tulpini de enterobacterii.

AIM: To evaluate the susceptiblity of extended spectrum beta-lactamase (ESBL) producing organisms among Escherichia coli and Klebsiella pneumoniae, isolated between January-October 2009 from hospital and community. MATERIALS AND METHODS: From 611 enterobacteria strains, for 112 strains (E. coli, n = 84 and K. pneumoniae, n = 28), the ESBL phenotypic confirmation was performed with double disk test (DDT) and the replacement disk method. The minimum inhibitory concentrations (MICs) for next antimicrobial agents tested: ceftazidime, cefotaxime, ceftriaxone, cefepime, cefpirome, imipenem, meropenem, ertapenem, moxifloxacin, gatifloxacin, levofloxacin, ofloxacin were performed by agar dilution method. Resistance rates were reported using the Clinical Laboratory Standard Institute (CLSI) breakpoints for the fully susceptible category; moderately susceptible isolates were classified as resistant. K. pneumoniae ATCC 700603 and E. coli ATCC 25922 were used for quality control. RESULTS: Resistance rates for ceftazidime, cefotaxime, ceftriaxone and aztreonam among tested strains were very high: 84.5%, 100%, 100% and 96.4% for E. coli and 98.8%, 98.8%, 97.6% and 89.2% for K. pneumoniae, with the MIC90 values > 256 mg/L for either antimicrobial tested agent. The MICs for fourth generation cephalosporins ranges from 4 mg/L to 512 mg/L. The MICs for tested quinolones were > 2 mg/L for 89.2% strains. Using breakpoint for susceptibility, all isolates were sensitive to ertapenem, imipenem and meropenem. CONCLUSIONS: We noticed a high resistance rate for ceftazidime, cefotaxime, ceftriaxone and aztreonam. In this study, carbapenems demonstrated the highest degree of activity.

[Microbiological evaluation of some commercial brands of Chamomillae floss]. / Controlul microbiologic al unor sorturi comerciale de Chamomillae flos.

UNLABELLED: Different strains of microorganisms contaminate medicinal herb, and theirs, enzymes could modify the normal composition of herbal products. MATERIAL AND METHODS: We evaluated the microbiological quality of 12 samples of Chamomillae floss commercialized in, markets and specific stores. Microbiological quality has been evaluated according European Pharmacopoeia rules. In all samples we determined the total number of germs, total number of fungi and we evaluated the presence of coliform bacilli, respectively Staphylococcus species. RESULTS: For all samples, the total number of germs was under the limits with variation between 320 CFU/g (P 4) and 14000 CFU/g (P 11). The total number of fungi was under the limits; in most of samples, we detected Penicillium sp. and Aspergillus sp. In 4 samples the total number of Escherichia coli strains was over the limits (100 CFU/g). CONCLUSIONS: An important decrease of total number of coliform bacilli was observed after boiling water has been added but the total number of germs was decreased insignificantly, so these extracts are not very safe for patient especially when vegetal products contain a great number of germs.

Antibacterial activity of some Artemisia species extract.

The antimicrobial activities of ethanol, methanol and hexane extracts from Artemisia absinthium, Artemisia annua and Artemisia vulgaris were studied. Plant extracts were tested against five Gram-positive bacteria, two Gram-negative bacteria and one fungal strain. The results indicated that Artemisia annua alcoholic extracts are more effective against tested microorganisms. However, all plants extracts have moderate or no activity against Gram-negative bacteria. The obtained results confirm the justification of extracts of Artemisia species use in traditional medicine as treatment for microbial infections.

[In vitro susceptibility of staphylococci to ciprofloxacin]. / Sensibilitatea in vitro a stafilococilor la ciprofloxacin.

OBJECTIVE: To evaluate the in vitro activity of ciprofloxacin against communitary and hospital staphylococcal strains isolated during 2006-2008 in Eastern region of Romania. MATERIAL AND METHODS: We have tested 1022 staphylococci strains, identified by conventional laboratory methods. Minimum inhibitory concentrations (MICs) were determined by agar dilution method, according to NCCLS. RESULTS: For both hospital and communitary isolates, MIC 90 was 0.25 mg/L (4 fold less than breakpoint for sensitivity). Resistance was absent or reduced (1.7%) for coagulase- positive staphylococci, both communitary and hospital. For coagulase negative staphylococci, resistance for clinical strains is increased (6%) compared to comunitary strains (0.3%). In conclusion, ciprofloxacin is highly effective against staphylococci representing a therapeutic option for multiresistant strains. Our data shown the necessity of adequate antibiotic use in the hospital and community.

In vitro antimicrobial activity and chemical composition of the essential oil of Foeniculum vulgare Mill.

UNLABELLED: In our study, four samples of volatile oil from Foeniculum vulgare, cultivated in different pedoclimatic conditions, were investigated for their antimicrobial activity and chemical composition. MATERIAL AND METHODS: Organisms. Staphylococcus aureus ATCC 25923, Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli ATCC 25922, Candida albicans were included in the report. Antimicrobial susceptibility tests. The comparative inhibitory activity of volatile oil samples with other antimicrobial agents was quantitative determined by minimum inhibitory concentration (MIC). Oil samples are the volatile oils extracted by steam distillation, from two ecological vegetative populations of Foeniculum vulgare. Gas chromatography coupled to mass spectrometry (GC-MS) was used to determine the chemical composition of the essential oils. RESULTS: All oil samples have a good activity against E. coli and S. aureus at low concentrations. Against B. cereus and P. aeruginosa these oil samples are less active. The oil samples were generally bactericidal at a concentration up to twofold or fourfold higher than the MIC value. Significantly synergic activity with amoxicillin or tetracycline showed all fennel samples against E. coli, Sarcina lutea and B. subtilis strains. Fennel oil samples have shown high activity against Candida albicans. CONCLUSION: No significant antimicrobial activity variations were observed for Foeniculum vulgare volatile oil samples obtained after two or three years cultivation period. The most important identified compounds in all samples of fennel volatile oils were trans-anethole, estragole, fenchone, limonene, alpha-pinene and gamma-terpinene.

Chemical composition and in vitro antimicrobial activity of essential oil of Melissa officinalis L. from Romania.

UNLABELLED: Melissa officinalis L. (lemon balm) is used in traditional medicine to treat insomnia, anxiety, gastric conditions, psychiatric conditions, migraines, hypertension and bronchial conditions. Natural essential oils (mixtures of fragrant chemical) obtained from various parts of plants are efficient active antimicrobial agents. The widespread use of antimicrobial agents selects resistant bacterial strains, which seriously compromise the effectiveness of antibiotic treatment. The use of herbal medicines might be a precautionary measure to prevent the development of lack of susceptibility to synthetic antibiotics that is associated with therapeutic failures. MATERIAL AND METHODS: In this work, the chemical composition and the antimicrobial properties of essential oil from romanian Melissa officinalis were determined. Therefore, the purpose of this study was to evaluate in vitro antimicrobial activity of lemon balm oil by comparison with lavender essential oil, which is also utilised for its antimicrobial properties in folk medicine. RESULTS: The most important identified compounds, well known for their antimicrobial effects were citral (neral and geranial) (16.10%), citronellal (3.76%) and trans-caryophyllene (3.57%).The lemon balm oil sample exhibited a higher degree antibacterial activity than did Lavandula oil against Gram-positive strains. The both oil samples tested has shown a high activity against Candida albicans. The gram-negative bacteria were not affected by the lemon balm oil.

[Erythromycin ethylsuccinate obtaining possibilities]. / Posibilitati de obtinere a etil-succinatului de eritromicina.

UNLABELLED: In this study we tried to improve the erythromycin ethylsuccinate obtaining, having in view to separate the erythromycin ester by crystallization in water. MATERIAL AND METHODS: The erythromycin acylation and the erythromycin ethylsuccinate crystallization were realized, following the next steps: 1. the acylation of the erythromycin with a methylene chloride solution of monoethylsuccinyl chloride, at 25-28 degrees C for 3 hours in the presence of NaHCO3; 2. the transfer of the erythromycin ethylsuccinate from methylene chloride solution in acetone solution by distillation of mixture methylene chloride: acetone 1:1 at 25-28 degrees C; 3. erythromycin ethylsuccinate separation by crystallization in water at pH = 8-8.5 and 5 degrees C for 90 minutes. The quality control for the erythromycin ester was performed according to the Xth edition of Romanian Pharmacopoeia standards using national standard for erythromycin ethylsuccinate and national standard for erythromycin with an activity of 1: 937 U and 2.02% humidity. The Micrococcus luteus ATCC 9341 was used as a test microorganism and a thin layer cromatography was performed for qualitative control. RESULTS: 13.1 g of erythromycin ethylsuccinate were obtained with an output of the process of 82.02%. Using water for the separation of erythromycin ethylsuccinate the output of the process is greater (82.02%) than in case of using petroleum ether (74.14%) or hexane (80.25%). The thin layer cromatography revealed an Rf = 0.56 and the microbiological activity of the erythromycin ethylsuccinate was 98.7% compared with the standard. CONCLUSIONS: Using water instead of hexane or petroleum ether is gainful for the separation of erythromycin ethylsuccinate from the reaction medium. The obtained erythromycin ethylsuccinate corresponds to the Xth edition of Romanian Pharmacopoeia standards. So, the raw materials consumption is decreased, the costs are cut down, the obtained product purity is high and the output of the process is greater.

In vitro study of staphylococci susceptibility to gatifloxacin.

UNLABELLED: Gatifloxacin is in a class of drug called fluoroquinolone antibiotics. It eliminates bacteria that cause many infections, such as pneumonia and bronchitis, sinus, respiratory tract and urinary tract infections and sexually transmitted diseases. Gatifloxacin ophthalmic solution is used to treat bacterial conjunctivitis. AIM: The purpose of this study was to evaluate the in vitro activity of gatifloxacin against recent 457 staphylococci, community isolates and compared it with that of pefloxacin. MATERIAL AND METHOD: Powders of gatifloxacin and pefloxacin, obtained from commercial sources were tested in concentration range from 0.125 to 64 mg/l. Minimum inhibitory concentrations (MICs) were determined by the agar dilution method established by NCCLS guidelines. RESULTS: The MIC 50 values for tested quinolones against coagulase-positive staphylococci are identically with MIC 90 (0.125 mg/l for gatifloxacin and 0.25 mg/l for pefloxacin respectively). Against coagulase-negative staphylococci the MICs 50 values were two-fold smaller than MICs 90 values for both gatifloxacin and pefloxacin. CONCLUSIONS: Gatifloxacin was more active than pefloxacin against coagulase-positive and coagulase-negative staphylococci.

Cefpirome susceptibility in staphylococci isolates.

UNLABELLED: Cefpirome is a fourth-generation cephalosporin with an expanded spectrum against both Gram-negative and Gram-positive bacteria. The objective of this study was to evaluate the in vitro activity of cefpirome against staphylococci, clinical isolates. For comparison oxacillin was also tested. MATERIAL AND METHODS: A total 434 isolates (coagulase-positive staphylococci, n = 268 and coagulase-negative staphylococci, n = 166) were tested. Susceptibility testing was performed using the Mueller-Hinton agar dilution method. RESULTS: Cefpirome inhibited the majority of strains at 0.5-8 mg/l. Cefpirome had excellent activity against coagulase-negative staphylococci with 91.6% susceptibility. Except the coagulase-positive staphylococci, of the 268 isolates, 81.3% were cefpirome sensitive. Concerning oxacillin, 35.1% of coagulase-positive staphylococci isolates were resistant, comparative with 26.5% of the coagulase-negative staphylococci. A cross-resistance analysis showed the association of resistance between cefpirome and oxacillin. CONCLUSION: Against staphylococci, cefpirome had the best activity when compared with the oxacillin.

[In vitro activity of ertapenem against staphylococci]. / Ertapenem: activitatea in vitro asupra stafilococilor.

UNLABELLED: Ertapenem is a new carbapenem with an excellent activity against different Gram-negative and Gram-positive bacteria. Its good antibacterial activity is closely related to high hydrolysis resistance by bacterial beta-lactamases. MATERIAL AND METHOD: We evaluated antimicrobial activity of ertapenem by comparison that of methicillin, gatifloxacin, cefepime and linezolid against 455 staphylococci collected during 2006-2007 period from healthy individuals. RESULTS: Minimum inhibitory concentrations were determined by agar dilution technique. Ertapenem has an activity comparable to the other tested agents. Resistance rate was 1% for all investigated strains.

Susceptibility of Klebsiella spp. to cefpirome and cefepime.

Cefpirome and cefepime possess a greater antibacterial spectrum in vitro than third-generation cephalosporins because they are active against Enterobacteriaceae, which produce beta-lactamases, which may inactivate third-generation cephalosporins. The aim of this study was to quantitatively compare the in vitro activity of cefpirome and cefepime against Klebsiella spp. isolates. We have studied 342 Klebsiella spp. clinical isolates, from some hospitals in Eastern Romania. Minimum inhibitory concentrations (MICs) were determined by the dilution method in Mueller-Hinton agar. The mean MIC of sensitive population by cefpirome and cefepime was 1 mg/l, eight fold lower than breakpoint for susceptibility. The cefpirome and cefepime MICs remained below the proposed breakpoints for sensitivity of 8 mg/l for more 60% of strains. Mean "S" (mean MIC of the fully sensitive strains) is a very good indicator of the drug activity. Cefpirome and cefepime are active fourth-generation cephalosporins against clinical isolates of Klebsiella spp.

Antimicrobial susceptibility of Staphylococcus aureus isolated from colonized hospital personnel.

The present study was performed to investigate the in vitro activity of oxacillin and other antimicrobial agents against S. aureus strains obtained from nursing personnel. We tested 127 S. aureus colonizing nasal mucous and hand skin and isolated from nursing personnel of University Hospital Department of Infectious Diseases, Iasi, during June 2005 period. Minimum inhibitory concentrations (MICs) were determined by the dilution method in Mueller-Hinton agar. Most of the S. aureus strains were susceptible to tested agents excepted erythromycin and azithromycin. Erythromycin and azithromycin resistance was observed among 29.1% respectively 22% of S. aureus strains. Vancomycin was active against all isolates. Teicoplanin was active against against all MRSA excepted one of the strain, with an reduced susceptibility. Linezolid has very good in vitro activity against staphylococci, with an MIC 90 of 2 mcg/ml and only 0.8% resistance. The MIC values range was between 0.5-2 mcg/ml. In conclusion, the usually hygienic methods (disposable gowns, hygienic hand disinfection after each patients contact, masks use when is a risk of aerosolization of MRSA) are indicate for significantly reducing of these strains.

Correlation between linezolid zone diameter and minimum inhibitory concentration values determined by regression analysis.

Linezolid is a new synthetic antibiotic belonging to the oxazolidinone class, available for the therapy of gram-positive infections, caused by methicillin-resistant staphylococci, vancomycin-resistant enterococci and penicillin-resistant pneumococci. The aim of the study was to determine the in vitro activity of linezolid against staphylococci strains and also to determine the relationship between the minimum inhibitory concentration (MIC) and inhibition zone diameter by calculating the regression analysis. We tested one hundred S. aureus isolates, obtained from healthy persons (naso-pharyngeal swabs) during 2005 year. The antibiotic susceptibility of strains was determined by disk diffusion standardized method and by agar dilution method using a multipoint inoculator. The relationship between the diameter of the inhibition zone produced by a linezolid disc impregnated with a fixed amount (30 eg) was determined by regression performed with the least squares method, considering the log2 of the minimum inhibitory concentrations (MICs) as the independent variable and the zone diameter as the dependent variable. The MIC values expressed in logarithmic form are plotted against inhibition zone diameter (arithmetic scale) of the same strain. The activity of linezolid against staphylococci was very good, with MIC 90 of 1 mg/l. All strains were fully sensitive. The regression line for linezolid passes through a continuous series of points that all are approximately located on the a straight line. For each of the MIC values the differences result no greater than 23 mm in diameter sizes were registered. Regression equation was y= -0.188x + 8.048. In conclusion, the regression line analysis calculated for linezolid, demonstrates a significant correlation between MIC values and the inhibition zone diameters obtained by a 30 mg disc.

[Phytochemical and microbiological characterization of two Allium cepa L. extracts in order to include in dermo-cosmetics]. / Caracterizarea fitochimica si microbiologica a doua extracte de Allium cepa L. în vederea includerii în dermopreparate.

We have obtained two Allium cepa extracts (C1 and C2) which were characterized from chemical and microbiological point of view. The C1 extract is the richest concerning the content in flavonoids, triterpenic acids, amino acids, compounds recognized for their beneficial effects in wound healing. All this data shows us the possibility of using the Allium cepa extracts in the treatment of wounds, scars. As well, the antimicrobial activity of the two extracts was evaluated. The C2 extract was efficient as antimicrobial agent, but there are necessary special preserving conditions.

[Susceptibility to norfloxacin of some bacterial strains causing urinary infections]. / Sensibilitatea la norfloxacin a unor tulpini bacteriene implicate in infectii urinare.

The purpose of this study was to evaluate the in vitro activity of norfloxacin in comparison with ofloxacin, pefloxacin and ciprofloxacin against 662 strains. The studied strains were obtained from urine, during 2003 period, in Eastern region of Romania. The minimum inhibitory concentrations (MICs) were determined on Mueller-Hinton agar by the dilution technique, with an inoculum of 10(5) CFU/spot. Among tested quinolones, norfloxacin has the better activity against tested strains. The fluoroquinolone compounds were very potent against Escherichia coil strains. Our data shown the spread of quinolone resistance in our area and demonstrated the necessity of adequate antibiotic use in the hospital and community.

[Meropenem activity against staphylococci]. / Activitatea meropenemului asupra stafilococilor.

Meropenem is a new carbapenem with excellent activity against different Gram-negative and Gram-positive bacteria. Its good antibacterial activity is closely related to high hydrolysis resistance by bacterial beta-lactamases. The aim of this study was to evaluate antimicrobial activity of meropenem by comparison that of oxacillin, gentamicin, clarithromycin and ciprofloxacin against 458 staphylococci collected during 2004 period from healthy individuals. Minimum inhibitory concentrations were determined by agar dilution technique. Meropenem has an activity clearly superior to the other tested agents. Resistance rate is zero for all investigated strains.

[In vitro susceptibility of a Staphylococcus spp. isolate to food preservatives]. / Sensibilitatea in vitro a unor izolate de Staphylococcus spp. la conservanti din produse alimentare.

Chemical food preservatives are incorporated into food products with the objective of preventing or delaying microbial spoilage and development of pathogenic microorganisms. In this study the in vitro activity of two esters of para-hydroxybenzoic acid (methyl paraben and propyl paraben) was investigated against 434 staphylococci isolates from healthy people. The agar dilution method was used for studying the antimicrobial activity. The investigated parabens were active against staphylococci with minimum inhibitory concentrations lower than commonly used levels for food preservation.

[New methyl-quinoxaline derivatives with antimicrobial activity]. / Nouveaux derivés de la 6-méthyle-quinoxaline doués d'activité antimicrobienne.

This paper presents the synthesis of six new quinoxaline derivatives cycloadditions products of N-monoxide and N,N'-dioxide of 6-methyl-quinoxaline. The chemical structure of new azabicyclic products was confirmed by C, H, N elemental analysis and spectral analysis (IR and RMN). We have tested the antimicrobial activity of the new synthesized azabicyclic derivatives by the diffusimetric method. The assay was made on the seven microorganisms, gram-positive and gram-negative bacteria. The results show that the new compounds are more active against the gram-positive bacteria and Candida albicans.