Chemical composition and in vitro antimicrobial activity of the essential oils of flower heads and leaves of Santolina rosmarinifolia L. from Romania.

The essential oils of the flower heads and leaves of Santolina rosmarinifolia L. (Compositae) cultivated in Romania were obtained through hydrodistillation and analysed by GC-MS. Forty-two components were identified, representing 92.3-94.0% of the whole composition of the samples. Their in vitro antimicrobial activity against gram-positive and gram-negative bacteria strains and the fungus Candida albicans was determined using the agar-diffusion method and the broth dilution method.

[Detection of extended-spectrum beta-lactamases production in enterobacteriaceae strains]. / Detectarea producerii de beta-lactamaze cu spectru extins la tulpini de Enterobacteriaceae.

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.

Resistance mechanism for a number of non-typhoidic Salmonella strains isolated in Iasi, 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.

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.

[Evaluation of sepsis prognosis using Saps II]. / Evaluarea prognosticului în sepsisul cu bacili gram-negativi prin scorul SAPS II (scorul fiziologic acut simplificat).

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.

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%.

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 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.

[Enterobacteriaceae isolated in eastern Romania: the evolution of ampicillin sensitivity in the 1970-1995 period]. / Enterobacteriaceae izolate în estul României: evolutia sensibilitatii la ampicilina în perioada 1970-1995.

The activity of ampicillin against 3383 Enterobacteriaceae (community and clinical isolates), collected in Eastern Romania, during 25 years was tested. Data were prelucrated by the box-plot method proposed by Simpson and Donnelly. The resistance degree for all species tested has progressively increased. In the studied region Enterobacteriaceae strains maintain their natural sensitivity only exceptionally: e.g., S. typhi and S. java, with limited circulation. Enterobacteriaceae which have contact with the resistance genic reservoir of the colon microbiota during the justified or nonjustified antibiotic treatment development resistance to usual antibiotics in the same ratio as most existent commensals present in this habitat.

Reduced susceptibility to co-amoxiclav in Escherichia coli, Salmonella typhimurium and Klebsiella pneumoniae isolated in Romania between 1985 and 1993.

By determining the beta-lactam susceptibility of Enterobacteriaceae isolated in Eastern Romania from 1985 to 1993, three Escherichia coli, three Salmonella typhimurium and one Klebsiella pneumoniae isolates with reduced susceptibility to co-amoxiclav were found. The antibiotic susceptibility of the isolates and their E. coli derivatives, and kinetic values suggested the following resistance mechanisms: hyperproduction of TEM in S. typhimurium, limited antibiotic uptake in K. pneumoniae and OXA production in one strain of E. coli. Despite a normal beta-lactamase activity, the two remaining E. coli strains and their derivatives were less susceptible to co-amoxiclav.

Development of resistance in Shigella flexneri isolates obtained in the past 20 years in eastern Romania.

Our study is focused on the antimicrobial activity for a number of 626 Shigella flexneri strains collected from epidemic outbreaks and hospitalised patients during 1976-1995 period, in Eastern Romania. The metodology used for determining the in vitro activity of the antimicrobials was that described by NCCLS. The agents which are currently used in therapy (ampicillin, tetracycline, chloramphenicol) are less active than the newer drugs (third generation cephalosporins, aztreonam, imipenem, ciprofloxacin) for which sensitivity ranged between 93-100% The associated resistance between ampicillin, tetracycline, chloramphenicol was demonstrated. Isolates with MIC values for ampicillin > 8 micrograms/ml are still sensitive to the modern beta-lactams. For ampicillin/sulbactam association, sensitivity decreases from 100% in 1990-1993 to 43% in 1994-1995.

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]. / Noi derivati de pirazolo- si tetrazolo-benzocinolina cu actiune antimicrobiana.

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]. / Cercetari farmacologice asupra sulbactamei si asocierii sale cu unele antibiotice beta-lactamice de semisinteza.

The acute toxicity, local tolerance and pharmacokinetic properties of sulbactame manufactured by the Iasi 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.