[Research for the improvement of acylation conditions in antistaphylococcal penicillin synthesis]

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]

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.

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.

[Microbiological evaluation of some commercial brands of Chamomillae floss]

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.

[Erythromycin ethylsuccinate obtaining possibilities]

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 susceptibility of staphylococci to 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

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

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.

In vitro study of staphylococci susceptibility to gatifloxacin

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

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.

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, 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.

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.

[Phytochemical and microbiological characterization of two Allium cepa L. extracts in order to include in dermo-cosmetics]

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]

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]

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]

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]

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.

A study for the improvement of the cytological urine examination performances in upper tract infection diagnosis

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.

[Activity of fourth generation cephalosporins against clinical isolates of Enterobacteriaceae]

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).

[In vitro antibacterial activity and beta-lactamase stability of meropenem]

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.

In vitro susceptibility of staphylococci to linezolid and other antimicrobial agents

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.

Resistance pattern of extended-spectrum beta-lactamase producing Enterobacteriaceae isolates

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.

[Detection of extended-spectrum beta-lactamases production in enterobacteriaceae strains]

Extended-spectrum beta-lactamases (ESBL) cause resistance to ceftazidime, ceftriaxone, cefotaxime and other cephalosporins. The ESBL enzymes are most often derivatives of beta-lactamases from the TEM or SHV group. The aim of our work was to study ESBL production by 35 ceftazidime-resistant strains. We selected these strains among 335 Enterobacteriaceae, isolated in Eastern Romania from healthy carriers and patients, between january-june 1999. To identify the studied strains we used API 20E and API 32E. The ESBL production was established by using both double disk synergy test (DDT) and EXPERT computer program of miniAPI (Bio Merieux). We revealed ESBL production in 26 strains when EXPERT program was used and only 23 when DDT was used. Our results suggest that miniAPI is a better method to study ESBL production than DDT.

Sensitivity of Enterobacteriaceae strains to the third generation cephalosporins

The aim of this study was to evaluate the in vitro activity of cefotaxime, ceftriaxone, ceftazidime, ceftibuten and aztreonam against the clinical isolates of Enterobacteriaceae. MICROORGANISMS: A total of 973 enterobacteria isolated from clinical material (urine and faeces) were tested. Strains were collected during 1996-1998 period, in some centers of Eastern Romania. SENSITIVITY STUDY: MICs were performed using the agar dilution method following standardized techniques (NCCLS, 1994). Stock solutions of antibacterial agents were prepared from their respective powder forms, in concentrations ranging from 0.03 to 128 mg/ml. Our results show a good activity of the tested antimicrobials on Escherichia coli, Shigella spp and Klebsiella spp tested, and reveal a particular behaviour for Salmonella spp, characterized by a heterogenous susceptibility. In conclusion, cefotaxime, ceftriaxone, ceftazidime, ceftibuten and aztreonam were active at low concentrations against tested isolates. Against Salmonella spp, these agents were less active: percent of resistant strains by beta-lactamase production was significant.

Resistance mechanism for a number of non-typhoidic Salmonella strains isolated in Iaşi, Romania

The aim of this study was to find a possible explanation for the resistance pattern of the selected strains and to evaluate the impact in case of isolating such strains. During the period February-March 1998, in the Pediatric Hospital "Sf. Maria" from Iasi, Romania, 12 non-typhoidic Salmonella strains, non-duplicates were isolated from stools of newborns and, in one case, from mother as well. Identification was done by standard methods, and sensitivity testing by disk diffusion method, against the following antimicrobials: Ampicillin (A), Amoxycilin/Clavulanic Acid (AMC), Tetracycline (T), Streptomycin (S), Cloramphenicol (C), Nalidixic Acid (NA), Ciprofloxacin (CIP), Cephalotin (KF), Cefuroxime (CXM), Ceftriaxone (CRO), Cefotaxime (CTX), Ceftazidime (CAZ), Aztreonam (AZT), Imipenem (IPM), Amikacin (AK). All strains showed resistance to: A, AMC, T, S, C, NA, CRO, CAZ, CXM, CTX, KF except one strain, CTX and CRO sensitive. The possible explanation is the production of an extended-spectrum beta-lactamase (ESbLA), detected by microbiological methods (Masuda and clover-leaf). Resistance transfer was realised by using the previously described method. In conjugation experiments we have obtained only one transconjugant, identified as E. coli, that has acquired all resistance determinants. This report highlights on the isolation of multiresistant non-typhoidic Salmonella strains in hospitalised patients without previous antibiotic treatment and possibility of detecting such strains by being aware of the correlation: resistance phenotype-resistance mechanism.

[Evaluation of sepsis prognosis using Saps II]

The simplified acute physiological score (SAPS II), the only valid score in sepsis according Pilly (1997) includes 17 variables: 12 physiological variables, age, type of admission and 3 variables that reffer to the background diseases: AIDS, neoplasm and haematologic malignant diseases. SAPS II was used in 30 patients with sepsis. The evaluation for each variable were between 0-26 points. Our data suggest that values over 0.552 coincided with death in 12 patients and values below 0.552 coincided with a favourable course in 18 patients.

Mercury resistance among clinical isolates of Escherichia coli

The use of organomercurials in liquid detergents and disinfectants promoted resistance to mercury among bacteria. Dental amalgam and industries using mercury are the main source of human exposure to mercury vapor. Release of mercury from dental amalgam contributes to the enrichment of the intestinal flora with mercury resistance plasmids which may be associated with antibiotic resistance. The aim of our study was to evaluate the frequency of E. coli strains resistant to mercury and other antimicrobial agents currently used in therapy. The bacterial mercury and ampicillin, cephalexin, cefotaxime, gentamicin, tetracycline and chloramphenicol resistance was tested against 363 E. coli strains obtained from faeces and urine between 1999-2000. According to the guidelines suggested by NCCLS (1998), minimum inhibitory concentrations (MICs) were determined on Mueller-Hinton agar, using the dilution technique with an inoculum of about 10(5) CFU. The MICs were read after 18 h incubation at 37 degrees C as the lowest concentration that inhibited the development of visible growth. Plasmids in enterobacteria may carry genes encoding resistance to both mercury and antibiotics. Among the tested E. coli strains, mercury resistance rose to 29.2%. Mercury resistance in E. coli is significantly linked to multiresistance to antimicrobial agents. Between 91.5-23.6 of mercury chloride resistant isolates were also resistant to the tested antibiotics. The increased use of non antibiotic antimicrobial agents is a possible selection factor for antibiotic-resistant strains in clinical and domestic environments.

The frequency of in vitro resistance to fluoroquinolones among clinical isolates of Escherichia coli

The aim of this study was to investigate the activity of new quinolones against clinical isolates of E. coli, obtained from hospitalized patients between 1999-2000, in Eastern Romania. We tested 411 strains, isolated from urine. Susceptibility of the isolates to norfloxacin, ciprofloxacin, nalidixic acid and ofloxacin was performed using the dilution method in Mueller-Hinton agar. Susceptibility was reported using the NCCLS breakpoints. Minimum inhibitory concentration (MIC) was defined as the lowest concentration of antimicrobials that inhibited growth of the bacteria. Based on MIC breakpoints for defining susceptibility, between 12.4-13.7% of isolates were resistant to modern quinolones. Resistance to nalidixic acid significantly diminished the clinical use: level of the susceptible strains was only 12.9%.

The antimicrobial susceptibility of Escherichia coli isolated in eastern area of Romania. A surveillance study

To evaluate the resistance trends for Escherichia coli isolates during 1993-1999 period in Eastern Romania to: ampicillin (A), ampicillin-sulbactam (A/S), ceftazidime (CAZ), cefotaxime (CTA), ceftriaxone (CRO), aztreonam (AZT), ofloxacin (OF), ciprofloxacin (CIP), tetracycline (T) and chloramphenicol (C). We tested 2012 clinical isolates obtained from faeces and urine. MICs were determined by a dilution method in Mueller-Hinton agar (NCCLS guidelines). Resistance rates were analyzed using the NCCLS breakpoints for the fully susceptible category (moderately susceptible strains were classified as resistant). No significant differences were observed in susceptibility of E. coli to ampicillin and ampicillin/sulbactam in the last years. The high percentage of resistant isolates was observed in 1995 for ampicillin (89.7%). Higher incidences of resistance were detected for A, A/S, T; the addition of sulbactam restored A susceptibility only for a small percent. CAZ, CTA, CRO, AZT, OF and CIP resistance among E. coli isolates was progressively increased in the last period.

Detection of beta-lactamase production and enzyme profiles in Enterobacteriaceae isolated in Moldova

In our study, out of 449 Enterobacteriaceae strains isolated between 1985 and 1990, 16 strains (3 Proteus, 6 nontyphoidal Salmonella, 7 Escherichia coli) were resistant both to Ampicillin- Sulbactam and Amoxycillin-Clavulanic acid associations. The activity profiles of the beta-lactamases produced by these resistant strains are described. Sarcina lutea ATCC 9341 was used as test strain. The effect of the enzymatic filtrate against beta-lactam antibiotics: Ampicillin, Cloxacillin, Cefadroxil, Cefuroxime, Cefotaxime, Ceftriaxone, was followed up. The enzyme types were established according to the ability of inactivating the tested antibiotics. Penicillins and cephalosporins were inactivated by these enzymes, except for Carbenicillin and Oxacillin. These beta-lactamases were resistant to Sulbactam and Clavulanic acid. In the studied Salmonella strains they are plasmidic codified, demonstrating that they belong to a new beta-lactamase class.

[New derivatives of pyrazolo- and tetrazolobenzoquinolines with antimicrobial action]

The conditions for obtaining and the properties of some new diazabicyclic compounds is the new step in our investigation on the benzocynoline derivatives. The structure of the new compounds was confirmed by elementary (C, H, N) and spectral analyses. The antimicrobial tests evidenced that part of the newly synthetized compounds have a good antifungal action.

[Pharmacological studies of sulbactam and its association with semisynthetic beta-lactam antibiotics]

The acute toxicity, local tolerance and pharmacokinetic properties of sulbactame manufactured by the Iaşi Antibiotic Investigation Centre, alone or in association with ampicillin or amoxicillin were tested. Some tests were made comparatively with the product Unasyn--Pfizer. The obtained data show that this beta-lactamase inhibitor has a low toxicity--DL50 i.p. in mice over 4,000 mg/kg, both alone or associated with the two semisynthetic beta-lactamic antibiotics. The local tolerance is good and the serum levels of the above mentioned associations are above towards the tested bacteria and are similar or very close to those of Unasyn. It is believed that the therapeutical use of the association sulbactame + ampicillin or sulbactame + amoxicillin is very useful in the beta-lactamase producing germs infection.