Search

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.

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, Iaşi, 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.

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.

Modified Hodge test and a method using a disk with imipenem plus 1000 mg of EDTA were used to determine the presence of metallo-beta-lactamase producing gram-negative rods among 166 clinical isolates from hospitals in Iaşi and Galaţi. Of 9 imipenem resistant strains found, only one Pseudomonas aeruginosa gave positive results with both tests and other two P. aeruginosa clinical isolates gave negative results with both tests. The rest of the strains (2 P. aeruginosa, 2 Acinetobacter baumanii, 1 Sphingomonas paucimobilis) did not give conclusive results. These screening methods are useful, simple and accessible to clinical laboratories. PCR is needed to confirm the presence of metallo-beta-lactamase gene in bacteria and to determine the type of the enzymes.

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 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.

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.

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.

The comparative activity of meropenem with that of imipenem, cefotaxime, ceftriaxone and ceftazidime against 856 gram-negative bacilli was studied studied by an agar dilution method. Meropenem and imipenem were high active against tested strains. Resistance to third generation cephalosporins was high for most microorganisms tested. For rapid detection of metallo-beta-lactamase (MBL)-producing gram-negative bacilli a simple disk diffusion test was used. EDTA, FeCl2 and CuCl2 were evaluated as IMP-1 inhibitors. The method is helpful for screening of IMP-1 producers in daily clinical activity.

Cefpirome and cefepime are a novel group of cephalosporins which contain a positively charged quaternary ammonium at carbon 3 of the dihidrothiazone ring. The antimicrobial agents cefpirome, cefepime, cefotaxime, ceftriaxone, ceftazidime, cefoperazone and imipenem were tested against clinical isolates of Escherichia coli (n = 302) and Klebsiella spp. (n = 62) obtained during september-december 2002 from patients of Galaţi Emergency Hospital. The fourth generation cephalosporins cefpirome and cefepime have similar in vitro activities to the third generation cephalosporins. E. coli showed the comparable resistance rates for all cephalosporins. Against Klebsiella spp. strains cefpirome was less active (35.5% resistance) than cefepime (25.8% resistance). As expected, imipenem had excellent activity (100% susceptibility).

Diagnosis of the location of upper and lower urinary tract infection (UTI) is necessary in defining the therapeutic conduct that has a different period and intensity according to the infection location and in prognosis. Many studies show the lack of clinical criteria peculiarity in revealing the different location of UTI. As a result, the correct location of the level in which UTI develops is the necessity of paraclinical investigations. Urinary sample examination, in which urinary sediment microscopy is essential, is a reliable technique in fast detection and localization of UTI. Finding, in pyuria context, the classic significant bacteriuria (> or = 10(5) CFU/ml) or lower value bacteriuria (< or = 10(4) CFU/ml) confirms the UTI diagnosis. The upper tract infection prognosis increases when leukocyte cylinders, characteristic for pyelonephritis, appear together with intact or degraded leukocytes, single or grouped. We settled an algorithm to examine the urine samples in order to: Concentrate and preserve the structural integrity of leukocytes and cylinders, examining the conventional urinary sediment Precisely identify and differentiate these elements by vital coloration (leukocyte peroxidase coloration and Sternheimer - Malbin coloration) to establish more accurate the UTI level. The vital coloration for leukocyte peroxidase has cytological specificity, confirming the pyuria and the cylinders that contain leukocytes (leukocytary, granular, mixed) and obviously ameliorates the reliability and reproducibility of the urinary sediment cytological exam.

Gram-negative pathogens harboring extended-spectrum beta-lactamases (ESBL) are becoming an increasing therapeutic problem in many wards. The aim of our work was to study ESBL production by Enterobacteriaceae strains from Eastern Romania and their antimicrobial resistance. We selected 54 clinical isolates among 1068 enterobacteria according to their susceptibility spectrum (National Committee for Clinical Laboratory Standards, 1999). Antimicrobial susceptibility tests were performed using the Rapid ATB E gallery of mini API system (BioMérieux) and by a macrodilution method in Mueller-Hinton agar following standard procedure of the National Committee for Clinical Laboratory Standards (NCCLS). ESBL production was established by using both double disk synergy test (DDT) and Expert computer program of mini API. The isoelectric point (pI) was determined by isoelectric focusing in polyacrylamide gel and revealed by nitrocefin. As references we used beta-lactamases with known pI. The Expert computer program of mini API confirms the positive DDT test for all selected strains. Almost all strains displayed resistance to ampicillin, ampicillin/sulbactam or third generation cephalosporins and aztreonam. By IEF we identified 51 strains which have a unique enzyme. IEF pattern showed presence of two enzymes in three Escherichia coli strains. According to our results, the ESBL TEM-type are the most common for the studied isolates. The production of extended-spectrum beta-lactamases and the presence of the multiresistant of antimicrobial agents reflect, probably, the over use of third generation cephalosporins in Eastern Romania.

Linezolid is a member of the new class of antibacterial agents called oxazolidinones that are active against Gram positive organisms and exert their action by protein synthesis inhibition. In this study we investigated the in vitro activity of linezolid versus the other agent against clinical strains of staphylococci: Staphylococcus aureus (n = 82) and S. epidermidis (n = 32) collected in 2002 from hospitalized patients and healthy individuals, isolated from different biological samples. Agar dilution minimum inhibitory concentrations (MICs) were determined by using Mueller-Hinton agar according to the guidelines established by the National Committee for Clinical Laboratory Standards. Linezolid demonstrated excellent in vitro activity against all isolates tested, with MICs values in the range of susceptibility (< or = 8 microg/ml). No associated resistance between linezolid and other agents tested was observed. The resistance among Gram positive bacteria continues to spread and for many patients infected with these resistant organisms antimicrobial therapy is ineffective and linezolid may be a new alternative treatment.