P 1

FUNGAEMIA IN PATIENTS AT UNIVERSITY CLINICS-IDENTIFICATION RATE AND ANTIFUNGAL SUSCEPTIBILITY OF CANDIDA SPECIES

E. Dósa, D. Wilhelms, U. Dagwadordsch, A.S. Kekulé
Department of Medical Microbiology, Martin-Luther-University,
Halle/Saale, Germany

Blood cultures can be used to diagnose invasive candidiasis. Invasive fungal infections have increased over the past years, causing formidable morbidity and mortality among immuncompromised hosts. The frequency of nosocomial fungal infections has also increased among patients with cancer, organ transplant, burn and surgical infections. Due to the life threatening nature of these infections and reports of drug resistance, susceptibility testing of yeast pathogens is very important. During 3-years period (2000-2002), the culture results of 34 065 blood culture samples were reviewed. VITAL aerobe and anaerobe culture systems had been automatically agitated and continuously monitored for growing. The blood cultures examined in this study originated from ICU, haematology and transplantation wards of the University Clinic, Halle. Out of the examined 34 065 blood culture samples 17% were positive (mean: 3 samples/patient, min: 1, max: 13 samples/patient). During the study period, distribution of the identified species was as follows: aerobic bacteria 95% (gram-positive 72%, Gram-negative 28%) anaerobes 1%, Candida species 4%. Between 2000 and 2002 the C. albicans incidence declined from 65% to 41%, while the number of non-albicans strains was increasing. The identification of Candida species was performed by using ChromAgar Candida (BD) media, API 20 AUX and VITEK System YBC card (bioMérieux). The in vitro antifungal activities of amphotericin B, flucytosine, fluconazole and itraconazole against Candida species strains were investigated by E test.

P 2

COMPLEMENT SYSTEM IN PATIENTS WITH RHEUMATOID ARTHRITIS AND CSYOGLOBULINEMIA, ASSOCIATED WITH VIRUSES OF HEPATITIS B AND C

R.M. Balabanova, E.V. Shekshina, L.V. Kozlov
Institute of Rheumatology, Moscow, Russia
Gabrichevsky Institute of Epidemiology and Microbiology, Moscow, Russia

Objective: To evaluate the changes FCA in patients with RA and CGM, associated with hepatitis C and B virus.

Methods: We studied 74 patients with RA; average age was 48.9 ± 11.3; average duration of RA was 10.06 ± 8.3. Chronic viral hepatitis C (CVH C) was detected in 19 patients with RA (group 1), chronic viral hepatitis B (CVH B) was detected in 22 patients with RA (group 2). CGM was detected in 14 patients with RA (group 3). We studied 19 patients with RA (control group). The changes of FCA in patients with RA and CGM associated with hepatitis C and B virus were determined by microhaemolytical method.

Results: FCA was decreased in 6 patients with RA and CVH C, was absent in 4, was increased in 1 and normal in 4 cases. FCA was decreased in 5 patients with RA and CVH B, was absent in 3, was increased in 1 and normal in 8 cases. FCA was decreased in 5 patients with RA and CGM was absent in 6 and normal in 4 cases. FCA in patients with RA (control group) was decreased in 3 patients, was increased in 9 and normal in 8 cases. FCA in patients with RA and mixed viral infections was decreased in 5 patients and normal in 2 cases. Differences between the groups were statistically unreliable.

Conclusion: FCA was decreased and was absent in patients with RA and CVH C, B and CGM. FCA was increased and normal in most of patients with RA.

P 3

NEW COMPOUNDS WITH ANTIVIRAL PROPERTIES ON THE BASE OF E-AMINOCAPROIC AND
4-AMINOMETHYLBENZOIC ACIDS. STRUCTURE-ACTIVITY RELATIONSHIPS

D.N. Kryzhanovsky, R.N. Lozytska, V.P. Lozitsky, A.S. Fedchuk, V.E. Kuz’min, A.G. Artemenko
A.V. Bogatsky Physico-Chemical Institute of NAS, Odessa, Ukraine
Ukrainian I.I. Mechnikov Research Anti-Plague Institute, Odessa, Ukraine

Synthesis of symmetrical diamides of 2.6- and 2.6-dimethyl-3.5-pyridine dicarboxylic and terephthalic acids HOOCRNHC(O)XC(O)NHRCOOH which contain the fragments (R) of the well-known proteolysis inhibitors e-aminocaproic (E-ACA) and para-aminomethylbenzoic (PAMBA) acids were realized.
As a result of synthesized compounds anti-influenza and anti-HSV (Herpes) activity study it has been established:
when X = 2.6-Py and 2.6-Me2-3.5-Py, R = E-ACA and PAMBA appropriate diamides have shown the highest anti-HSV activity in comparison with compounds where X = 1.3-Ph and also in comparison with the native E-ACA and PAMBA in the same concentrations;
character of R-fragments exerts significant influence on anti-influenza activity independently of “bridge” X structure;
when R = PAMBA then anti-influenza activity of studied compounds essentially highest in comparison with an initial amino acid;
derivatives of E-ACA in studied concentrations didn’t show anti-influenza activity.
The antiviral properties of studied compounds were represented in rank scale and trend-vector procedure was used for constructing the hierarchical system of QSAR models – from topological to 3D. The QSAR investigation of mentioned diamides antiviral activity was carried out by means of molecular lattice approach.
The active sites of potential receptor were determined in region of molecular cavity and the “wall” of potential receptor was detected at a periphery of molecule.
The results of the QSAR investigations are discussed and the examples of synthesis of compounds with predictable high antiviral activity are given.
This research was partly supported by INTAS foundation (Grant INTAS 97-31528).

P 4

THE IN VITRO-ACTIVITY OF A NEW OXAZOLIDINONE (LINEZOLID) AGAINST FLUOROQUINOLONE-RESISTANT ENTEROCOCCI ISOLATED IN ROMANIA FROM JANUARY TO OCTOBER 2002

M. Ghita, M. Pana, I. Rebedea, S. Iacob, R. Papagheorghe, N. Popescu, S. Botea, D. Blana, D. Andries, V. Ungureanu, M. Andrei, G. Bancescu, I. Nistor
Cantacuzino Institute, Matei Bals Institute, Coltea Hospital, Maria Sklodowska Curie Hospital, Cantacuzino Hospital, Emergency Hospital, Carol Davila University, Grigore Alexandrescu Hospital, Romania

Objective: To study the antibiotic resistance in Enterococcus spp. isolated in Romania between January and October 2002.

Methods: 118 Enterococcus strains isolated between Jan.-Oct. 2002 were collected from: urine (N=47), surgical wounds (N=17), blood (N=13), drain (N=11), others (N=27): bile, sputum, synovial and peritoneal fluid, ear, sinus.The strains were characterized by using standard protocols and tested for beta-lactamase.The enterococci were studied for susceptibility to 7 antibiotics: amoxicillin (Amx), ciprofloxacin (Cip), norfloxacin (Nor), vancomycin (Va), gentamicin (Gn), streptomycin (Str) and Linezolid (Lzd) by three methods: disc diffusion, screening agar plates agar dilution according to NCCLS recommendations.

Results: The data were analysed according to NCCLS 2002 and showed the following aspects: 74.8% strains were identified as E. faecalis, 22.6% as E. faecium, 1.7% as E. durans and 0.8% as E. raffinosus. Amoxicillin resistance was seen in E. faecium only: 81.8% in urine, 100% in drain, 100% in surgical wounds and 100% in blood. No beta-lactamase producers were detected. Concerning E. faecium high level resistance (HLR) to Gn was 100% in drain, 100% in surgical wounds and 83.3% in blood, and HLR to Str was 40% in drain, 60% in drain, 60% in surgical wounds and 16.6% in blood. For E. faecalis HLR to Gn was 8.3% in surgical wounds and 28.5% in blood and HLR to Str was 33.3% in drain, 25% in surgical wounds and 14.2% in blood. Only one strain (E. faecium) resistant to Va in blood was found. Concerning Lzd intermediate resistance among fluoroquinolones (FQL) resistant E. faecium (80%) only one strain was noted. FQL resistant E. faecalis (33.3%) showed the same aspect: only one strain Lzd intermediate resistant.

Conclusion: The Lzd susceptibility pattern showed an excellent and nearly complete in vitro activity against the Romanian enterococci.

P 5

PENICILLIN SUSCEPTIBILITY TESTING OF STREPTOCOCCUS PNEUMONIAE BY OXACILLIN DISK SCREENING METHOD AND STANDARD BROTH MICRODILUTION METHOD

A. Tavakoli, R. Yazdani, M. Oshaghi
Isfaban Medical School University of Medical Science, Microbiology and Virology, Iran

Background: Despite the widespread use of antibiotic, Streptococcus pneumoniae remains a significant cause of morbidity and mortality among all age groups. Penicillin is the best treatment of pneumococcal infections. Isolates of pneumococci that are resistant to penicillin and other antibiotics are being found with increasing frequency, rapid recognition of penicillin resistance in the laboratory is critical for the proper selection of antimicrobial therapy. This study compared the oxacillin disk screening test with standard broth microdilution for determining antibiotic susceptibility of penicillin-resistant strains of streptococcus pneumoniae.

Methods: 327 clinical samples were collected, pneumococci strains were isolated from various parts of human body including blood, sputum,CSF… The minimal inhibitory concentration (MIC) of penicillin G determined by standard broth microdilution method. The diffusion method (Kirby & Bauer) with 1 mg oxacillin is used for first screening of penicillin-resistant pneumococci.

Finding: A total of 61 clinical isolates of S. pneumoniae were tested. The microdilution method classified 12 strains (19.6%) as penicillin, 38 strains (62.3%) relatively resistant, 11 (18.1%) highly resistant to penicillin. Among the isolated screened, 52 strains (85%) were resistant, 12 strains (15%) were susceptible to penicillin when tested with disk diffusion method. The oxacillin disk screen test for penicillin susceptibility has been shown to be false positive in 25% of cases when compared with standard method.

Discussion: Because of increasing frequency resistant, pneumococci to ß-lactam antibiotics in clinical isolates of streptococcus use of 1 mg oxacillin disk, which is rapid and cost-effective test is essential. This test is regarded as very sensitive but of low specifity because dose not distinguish between isolates highly resistant to penicillin and isolates with intermediate resistance. MIS determination is recommended for isolated strains from serious infections including pneumococcal meningitis and bacteremia.

Keywords: Streptococcus pneumoniae, Penicillin resistance, Antimicrobial susceptibility method

P 6

ANTIMICROBIAL RESISTANCE AMONG S. PYOGENES IN BAVARIA AND PHENOTYPES OF MACROLIDE RESISTANCE

R. Sauermann, R. Gattringer, W. Graninger, A. Buxbaum, A. Georgopoulos
Department of Internal Medicine I, Division of Infectious Diseases and Chemotherapy, Department of Internal Medicine IV, Division of Pulmology, University of Vienna, Vienna General Hospital, Austria

Background: In the last decades antimicrobial resistance among various bacterial pathogens has been rising steadily. This also applies to Streptococcus pyogenes (group A streptococci, GAS), a bacterial pathogen that causes a variety of diseases like tonsillopharyngitis, rheumatic fever and poststreptococcal glomerulonephritis.

Objective: This study was set out to assess the level of resistance of S. pyogenes to various antimicrobial agents and to investigate the phenotypes of macrolide-resistant isolates.

Methods: 540 isolates of S. pyogenes were collected in the year 2000 in Bavaria, Germany. The strains were derived from throat swabs from adult and infant outpatients with tonsillopharyngitis. The isolates were tested for their susceptibility to 16 antimicrobial agents (4 macrolides, 6 beta-lactams, 2 fluoroquinolones, tetracycline, clindamycin, linezolid and vancomycin) using the broth microdilution method. The phenotypes of macrolide resistance of the erythromycin-resistant strains were determined by a triple-disk diffusion test.

Results: All isolates were fully susceptible to penicillin and to the tested cephalosporins, fluoroquinolones, vancomycin and linezolid. Overall resistance rate to erythromycin was 13.3%. There was complete cross resistance of erythromycin, azithromycin and clarithromycin. The macrolide resistance rates differed between strains collected from adults (19.1%) and children (11.8%). Among the macrolide resistant strains the M phenotype predominated (78%).

Conclusion: Considering the steady rise of antimicrobial resistance to macrolides, continuous surveillance of this development is clearly warranted to permit optimal treatment regimens for GAS infections.

P 7

DISTRIBUTION OF MACROLIDE RESISTANCE GENES AMONG STREPTOCOCCUS PYOGENES COLLECTED IN CENTRAL EUROPE

H. Lagler, R. Gattringer, R. Sauermann, K. Stich, A. Buxbaum, W. Graninger, A. Georgopoulos
Department of Internal Medicine I, Division of Infectious Diseases and Chemotherapy, Department of Internal Medicine IV, Division of Pulmology, University of Vienna, Vienna General Hospital, Austria

In this study, a molecular characterisation of macrolide resistance mechanisms among S. pyogenes isolates collected in Germany, Austria and Hungary was conducted.
86 macrolide-resistant isolates out of 907 collected isolates were screened for macrolide resistance genes.
The mefA-, ermB and ermTR genes were detected by PCR amplification, using previously published primers. 
75.6% (n=65) of the analyzed isolates harboured mefA-, 10.5% (n=9) ermB- and 13.9% (n=12) ermTR genes. mefA and ermB were found combined in 5 strains and ermTR was always detected alone. The distribution didn´t vary widely between the countries and the geographical regions. The mefA-gene was the predominating resistance mechanism in all examined regions.
The study provides valuable data for the continued monitoring of the evolution of macrolide resistance development in the examined regions.
Accurate genotyping data are useful in determining empirical therapy, because this study shows that predicting the genotype from MIC phenotype is not always reliable as a 10.5% error rate was observed.

P 8

RESISTANCE PATTERNS AND PHENOTYPES OF 341 CLINICAL ISOLATES OF STREPTOCOCCUS PYOGENES COLLECTED IN AUSTRIA AND HUNGARY

R. Gattringer, R. Sauermann, U. Thaler, A. Buxbaum, W. Graninger, A. Georgopoulos
Department of Internal Medicine I, Division of Infectious Diseases and Chemotherapy; Department of Internal Medicine IV, Division of Pulmology; University of Vienna, Austria

Background: As one of the most common human pathogens Streptococcus pyogenes is a causative organism in many acute suppurative conditions. Serious complications can follow an infection with S. pyogenes. In view of the traditionally empirical approach to the treatment of bacterial infections, particularly in the community setting, the prevalence of current streptococcal resistance patterns and phenotypes should be taken into account when selecting the most appropriate antimicrobial therapy for a given infection.

Objective: This study was conducted to determine and to compare the antimicrobial susceptibility of streptococcal isolates to 4 macrolides and 12 other antibiotics in Vienna and Hungary (Budapest, Debrecen and Bertettyóújfalu). Another aim of this study was the evaluation of the macrolide-resistance phenotype.

Methods: A total of 341 clinical isolates of Streptococcus pyogenes from Vienna, Austria and three Hungarian cities were tested on their susceptibility to four macrolides and twelve other antibiotics by the broth microdilution method. Macrolide resistant isolates were subjected to the triple erythromycin- clindamycin-josamycin disk diffusion test for determination of the phenotype of macrolide resistance.

Results: All 341 isolates were fully susceptible to penicillin, amoxicillin and four tested cephalosporins. None of the isolates were resistant to fluoroquinolones, linezolid and vancomycin. Surprisingly a high resistance level to tetracycline was found (26% in Vienna and 30.5% in Hungary). Overall the rate of erythromycin resistance was 4.1% (4.7% in Vienna and 3.7% in the Hungarian communities). The same results were found for azithromycin and clarithromycin. Using the tentative breakpoints of the NCCLS and the French Society of Microbiology a MIC50/90 of 0.06/0.25 mg/l for erythromycin and clarithromycin were found as well in Hungary as in Vienna. The MIC50/90 of azithromycin and josamycin were 0.25/0.25 mg/l and 0.25/0.5 mg/l, respectively, in both countries. Thereby in both countries the M phenotype of resistance, characterized by full susceptibility to josamycin, was found to be predominating.

Conclusion: Thus, a low rate of macrolide resistance in S. pyogenes was shown in Vienna and the three Hungarian cities. Remarkable differences in resistance patterns and phenotype distribution could not be found. However, with respect to the presently low rates of macrolide resistance, this group of antibiotics appears to remain a useful and adequate remedy for S. pyogenes infections in patients allergic to penicillin in the examined regions.
But having the resistance situation of many countries in view, further careful surveillance of macrolide resistance and resistance phenotypes is required to follow changes in resistance patterns as changes can be expected due to the increasing levels of macrolide consumption.

P 9

COMPARISON OF ENTEROTOXIN GENES IN STAPHYLOCOCCUS AUREUS STRAINS FROM PATIENTS VS. HEALTHY CARRIERS

H. Lagler, C.L. Maródi, K. Stich, A. Georgopoulos, W. Graninger, F. Rozgony
Dept. of Infectious Diseases and Chemotherapy, General Hospital, University of Vienna, Austria. 2Inst of Medical Microbiology, Semmelweis University, Budapest, Hungary

Materials and methods: The presence of mecA-, enterotoxin (A-E and G-Q), TSST-1 genes was detected by the PCR technique in 161 strains of Staphylococcus aureus (SA). Strains (n=137) were collected at Semmelweis University from throats, anterior nares and hands of healthy students, and at the Department of Pulmology (DP) from sputum, throat, or bronchial lavage (BAL) of patients (n=24). All isolates were identified by the classical methods. Antibiotic susceptibility was determined by microdilution (oxacillin), agar plate dilution (vancomycin) and disc diffusion (others). Phage types were determined by the standard international collection of phages.

Results: 87.5% (21) of the isolates from DP, and 74% (101) in the students group harboured enterotoxin genes. In the 24 DP-strains SE-gene distribution was as follows: SEA 25% (6), SEB 16% (4), SEC 0%, SED 12.5% (3), SEE 0%, TSST-1 4.2% (1), SEG 62.5% (15), SEH 0%, SEI 62.5% (15), SEJ 12.5% (3), SEK 4.2% (1), SEL 0%, SEM 62.5% (15), SEN 66.7% (16), SEO 62.5% (15), SEP 25% (6), SEQ 12.5% (3). One strain was mecA-gene positive. In contrast, the 137 strains from students showed the following distribution: SEA 16% (22), SEB 11% (15), SEC 11.7% (16), SED 11% (15), SEE 1.5% (2), TSST-1 6.6% (9), SEG 34.3% (47), SEH 5.1% (7), SEI 38% (52), SEJ 11% (15), SEK 10.2% (14), SEL 11% (15), SEM 37.2% (51), SEN 38.7% (53), SEO 38% (52), SEP 5.8% (8), SEQ 16.1% (22). No mecA-gene was detected.

Conclusion: The overall number of SE-gene positive SA were (87% vs. 73.7%) in both groups high. Surprisingly, no MRSA was found in the students and only one in the patients. The most frequent SE-genes in the collection are SEG, SEI, SEM, SEN, SEO. The genes were mostly found combined and were present almost twice as frequent in patients strains as in those of healthy carriers. The 5-fold higher frequency of SEP in patients isolates is noteworthy.
Supported by ÖAAD-MÖB.

P 10

ACTIVITY OF LINEZOLID IN COMPARISON WITH VANCOMYCIN, QUINOPRISTIN/DALFOPRISTIN, LEVOFLOXACIN, AND MOXIFLOXACIN AGAINST CLINICAL ISOLATES OF STAPHYLOCOCCI

W. Pfister, H. Weisser, S. Eick, E. Straube
Institute of Medical Microbiology, University of Jena, Germany

Antimicrobial resistance among gram-positive bacteria has increased and new antibiotics have been introduced during the last years. Our study was to evaluate the in vitro activities of linezolid (LIZ) in comparison with vancomycin (VAN), quinopristin/dalfopristin (SYN), levofloxacin (LFX), and moxifloxacin (MOX) to staphylococci.
7 245 clinical isolates were investigated in a prospective study over 24 months. The isolates had been identified as pathogens, not as part of the normal flora. They included 4 072 methicillin-susceptible S. aureus (MSSA), 212 methicillin-resistant S. aureus (MRSA), 868 methicillin-susceptible S. epidermidis (MSSE), 1 015 methicillin-resistant S. epidermidis (MRSE), 198 methicillin-susceptible S. haemolyticus (MSSH), 439 methicillin-resistant S. haemolyticus (MRSH), 304 methicillin-susceptible strains of other coagulase-negative staphylococci (MSCoNS), and 137 methicillin-resistant strains of such staphylococci (MRCoNS). The MIC-values were determined by broth microdilution assay (MICRONAUT-S-GENARS, Merlin, Bornheim-Hersel, Germany.
MIC50 and MIC90 (mg/L) were:
LIZ: 1/2 (MSSA), 1/2 (MRSA), 0.5/1 (MSSE), 0.5/1 (MRSE), 0.5/1 (MSSH), 0.5/1 (MRSH), 0.5/1 (MSCoNS), 0.5/1 (MRCoNS)
VAN: 1/1 (MSSA), 1/1 (MRSA), 1/1 (MSSE), 1/2 (MRSE), 0.5/1 (MSSH), 1/2 (MRSH), 0.5/1 (MSCoNS), 1/2 (MRCoNS)
SYN: 0.5/1 (MSSA), 1/1 (MRSA), 0.5/0.5 (MSSE), 0.5/0.5 (MRSE), 0.5/1 (MSSH), 0.5/1 (MRSH), 0.5/1 (MSCoNS), 0.5/1 (MRCoNS)
LFX: 0.125/2 (MSSA), 4/16 (MRSA), 0.25/8 (MSSE), 4/8 (MRSE), 0.125/8 (MSSH), 4/16 (MRSH), 0.25/1 (MSCoNS), 4/16 (MRCoNS)
MOX: 0.063/1 (MSSA), 2/4 (MRSA), 0.125/2 (MSSE), 1/2 (MRSE), 0.125/2 (MSSH), 1/4 (MRSH), 0.125/0.5 (MSCoNS), 1/4 (MRCoNS).

Apart from some elevated MIC-values, especially of LFX and MOX, the antimicrobials tested exhibited good activities to methicillin-susceptible as well as methicillin-resistant staphylococci. No resistance to LIZ could be detected.

P 11

EVALUATIONS OF ANTIMICROBIAL RESISTANCE IN GROUP A STREPTOCOCCI

T. Gryshaeva, B. Belov, S. Sydorenko, G. Sterhova, M. Zubkov
Institute of Rheumatology of RAMS, National Research Center of Antibiotics, Moscow, Russia

Objectives: Penicillin (PEN) is the drug of choice for the treatment of Streptococcus pyogenes (GABHS) infection. For penicillin-allergic patients, antibiotic treatment with macrolides has been traditionally used. But resistance to macrolide antibiotics has been widely reported. The aim of this study was evaluation of antimicrobial susceptibility of recent throat isolates of GABHS collected from Russian people to different antibiotics.

Methods: 44 GABHS were isolated by swabbing the throats of people, 14 to 30 years old, with acute tonsillitis. The isolates were identified as GABHS by colony morphology, beta-haemolysis on blood agar, and an agglutination technique (PASTOPEX®STREP). The methods of antibiotic dilution for determining susceptibility was performed in accordance with the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). 11 antibiotics were selected for study: PEN, erythromycin (ER), clarithromycin (CLT), azithromycin (AZT), spiramycin (SP), clindamycin (CLD), chloramphenicol (CHL), ofloxacin (OFL), levofloxacin (LEV), moxifloxacin (MOX), doxycycline (DOX).

Results: None of 44 GABHS isolates was resistant to PEN and CLD. Macrolide resistance was present in 16-20.5%. Those strains that were resistant to ER were also resistant to CLT and AZT, but susceptible to 16-member macrolide (SP) and CLD (M-phenotype resistance). DOX resistance in this sample of group A streptococci was 68%.

Conclusion: PEN remains the drug of choice for acute GABHS tonsillitis for primary prevention of acute rheumatic fever. Patients allergic to PEN may receive macrolide. But macrolide treatment of GABHS respiratory infections should not be promoted as first-line therapy because the consequent increase of bacterial resistance could create difficulties in treating penicillin-allergic patients.

P 12

ACTIVITY OF QUINOLONES TO ORAL ANAEROBIC AND CAPNOPHILIC BACTERIA

S. Eick, W. Pfister
Institute of Medical Microbiology, University of Jena, Germany

Anaerobic and capnophilic bacteria possess a key role in etiology of aggressive periodontal diseases and odontogenic abscesses. To determine the susceptibility of these microorganisms to quinolones the following bacteria were included in our study: non pigmented Prevotella spp. (31), black pigmented Prevotella spp. (24), Fusobacterium nucleatum (18), Porphyromonas gingivalis (17), Veillonella spp. (9), gram-positive oral anaerobes (9), Actinobacillus actinomycetemcomitans (8), and other capnophilic gram-negative rods (10). Quinolones tested were ciprofloxacin, levofloxacin, moxifloxacin, and trovafloxacin. Determinations of the MIC-values were performed by agar-dilution tests on Wilkins-Chalgren-agar with 10% sheep blood using a multipoint inoculator. Anaerobic and capnophilic microorganisms tested were clinical isolates from subgingival plaque samples of 29 patients with aggressive periodontitis and from pus samples of 24 patients with odontogenic infections. Results of the investigation performed showed the highest susceptibility to moxifloxacin. The MIC50 values of all strains tested were as follows: ciprofloxacin = 1.0 µg/mL, levofloxacin = 0.5 µg/mL, moxifloxacin = 0.064 µg/mL, and trovafloxacin = 1.0 µg/mL. In comparison the MIC90 values were: ciprofloxacin = 4.0 µg/mL, levofloxacin = 2.0 µg/mL, moxifloxacin = 0.38 µg/mL, and trovafloxacin = 4.0 µg/mL.

The results of this in vitro study show the better effectiveness of the newly developed quinolone moxifloxacin to oral anaerobic and capnophilic species compared with the other antibiotics. Therefore this antibiotic might be an alternative for the antibiotic treatment of odontogenic infections and aggressive forms of periodontal disease.

P 13

IN VITRO ANTIMICROBIAL RESISTANCE OF THE MOST COMMON GRAM-NEGATIVE PATHOGENS IN AUSTRIA

S. Forsthuber, A. Georgopoulos, W. Graninger
Dept. of Infectious Diseases and Chemotherapy, University of Vienna, Austria

Objective: To evaluate the prevalence, epidemiology and in vitro antimicrobial resistance of gram-negative bacteria, in particular multi-resistant and cross-resistant strains.

Material and methods: A total of 761 isolates of gram-negative bacteria were collected by 10 centers in Austria. 601 enterobacteriaceae (EB) and 160 non-fermenting gram-negative bacilli (NFGNB) were identified using standard laboratory methods. MICs for ampicillin (AMP), amoxicillin-clavulanic acid (AMC), piperacillin (PIP), imipenem (IMI), cefuroxime (CXM), cefotaxime (CTX), ceftriaxone (CTR), ceftazidime (CAZ), cefpirome (CPO), cefepime (CEP), gentamicin (GEN), ofloxacin (OFL), ciprofloxacin (CIP), grepafloxacin (GRP), levofloxacin (LEV), gemifloxacin (GEM), trovafloxacin (TRV), moxifloxacin (MXF) and trimethoprim-sulfamethoxazole (COT) were determined by the broth microdilution method according to NCCLS criteria.

Results: The majority of organisms were isolated from the respiratory tract, urogenital tract and skin and soft tissue. Resistance rates for EB: beta-lactams (from 72.5% to 0.2%), fluoroquinolones (from 11.5% to 8%), gentamicin 7% and cotrimoxazol 17%.
Resistance rates for NFGNB: beta-lactams (from 73% to 12%), fluoroquinolones (from 38% to 8%), gentamicin 45%, cotrimoxazol 51%. 16% EB and 49% NFGNB were resistant against 5 or more agents. 4% EB and 26% NFGNB were cross-resistant against several fluoroquinolones, beta-lactams, gentamicin and cotrimoxazol.

Conclusion: Cross- and multi-resistance are important problems of all NFGNB, in particular for Pseudomonas aeruginosa and Stenotrophomonas m., and for Enterobacter spp., Morganella m., Proteus mirabilis and Serratia spp. Cross-resistance was not as frequently seen in E. coli, Klebsiella oxytoca and Proteus vulgaris while AMP was the most active substance against NFGNB, IMI, CPO and CEP showed the best results against EB.

P 14

SUSCEPTIBILITY TO SELECTED ANTIBIOTICS OF STAPHYLOCOCCI AND ENTEROCOCCI ISOLATED FROM DIFFERENT INFECTION SITES

S. Forsthuber, A. Georgopoulos, W. Graninger
Dept. of Infectious Diseases and Chemotherapy, University of Vienna, Austria

Objective: The present study was performed to investigate the distribution of staphylococci and enterococci in different infection sites and their susceptibility to selected antimicrobial agents.

Material and methods: A total of 306 gram-postive strains from 279 inpatients and 27 outpatients were collected by 10 centers in Austria between February 1999 and July 1999. 108 coagulase-negative staphylococci (CoNS), 50 MSSA, 50 MRSA, 50 Enterococcus faecalis and 48 Enterococcus faecium were tested against the following antibiotics: linezolid (LNZ), vancomycin (VAN), fusidic acid (FUS), netilmicin (NET), gentamicin (GEN), trovafloxacin (TRV), levofloxacin (LEV), cefpirome (CPO), cefepime (CEP), penicillin (PEN), ampicillin (AMP), amoxicillin-clavulanic acid (AMC), piperacillin (PIP). MIC values were determined by broth microdilution according to NCCLS guidelines.

Results: Distribution: The majority of organisms were isolated from skin and soft tissue, urogenital tract and respiratory tract. Susceptibilities of E. faecium/E. faecalis: LNZ (100%/100%), VAN (100%/100%), PEN (17%/98%), AMC (31%/98%), AMP (21%/98%), PIP (10%/92%) and LEV (13%/78%). Susceptibilities of MSSA/MRSA/CoNS: LNZ (100%/100%/100%), VAN (100%/100%/100%), AMC (96%/20%/75%), CPO (100%/18%/73%), CEP (94%/10%/66%), FUS (90%/86%/66%), NET (90%/38%/89%), GEN (88%/6%/61%) and TRV (96%/40%/63%).

Conclusion: Although we found substantial differences in antibiotic susceptibility between enterococci and staphylococci, the most active antimicrobial agents among both were linezolid and vancomycin.

P 15

ANTIBIOTIC SUSCEPTIBILITY OF BACTERIAL STRAINS ISOLATED FROM COMMUNITY- ACQUIRED RESPIRATORY TRACT INFECTIONS IN AUSTRIA 2002

S. Forsthuber, A. Buxbaum, A. Georgopoulos, W. Graninger
Dept. of Infectious Diseases and Chemotherapy, University of Vienna, Austria

Objective: The aim of this study was to determine the susceptibility of the most common bacterial pathogens in respiratory tract infections.

Material and methods: Between January 2002 and December 2002 a total of 658 strains were collected from 361 adults and 297 children with community acquired respiratory tract infections from different Austrian regions. 282 Staphylococcus aureus, 150 Streptococcus pyogenes, 120 Haemophilus influenzae and 106 Streptococcus pneumoniae were identified according to standard laboratory techniques. Antimicrobial susceptibility testing was performed by broth microdilution method according to NCCLS guidelines. The following antibiotics were tested: erythromycin (ERY), clarithromycin (CLA), azithromycin (AZI), telithromycin (TEL), penicillin (PEN), amoxicillin-clavulanic acid (AUG), ampicillin (AMP), cefotaxime (CTX), cefpodoxime (CPD), ciprofloxacin (CIP), levofloxacin (LEV), moxifloxacin (MXF), gatifloxacin (GAT), tetracyclin (TET), quinupristin-dalfopristin (SYN), linezolid (LNZ), vancomycin (VAN), gentamicin (GEN) and fusidic acid (FUS).

Results: 72% (n=475) of the strains were isolated from upper respiratory tract and 28% (n=183) from lower respiratory tract. Against S. aureus the most active agents were LNZ (100%), VAN (100%), LEV (99%), MXF (99%), and FUS (99%). PEN, LNZ, MXF, GAT, LEV, CTX and CPD showed the best activity against S. pyogenes (from 100% to 99). The most active agents against S. pneumoniae were AUG, LNZ, MXF, TEL, CTX (100% susceptible). Among H. influenzae 100% were susceptible among CIP, LEV, MXF, GAT, TEL, CTX and CPD.

Conclusion: The results demonstrate that the resistance rates of the respiratory tract pathogens among most antibiotics were under 10%.

P 16

DETECTION OF METALLO-ß-LACTAMASE PRODUCING STRAINS OF PSEUDOMONAS AERUGINOSA AND ACINETOBACTER SPECIES BY USING E TEST, DISK SYNERGY AND PCR TESTS IN TURKEY

Ç. Bal, Z. Aktas, M. Salcioglu
Istanbul University, Istanbul Faculty of Medicine, Department of Microbiology and Clinical Microbiology, Istanbul, Turkey

Objective: Metallo-ß-lactamase (MBL) positive Pseudomonas aeruginosa isolates have increasingly been reported recently. These clavulanate-resistant MBLs have a very broad hydrolysis profile including carbapenems and extended-spectrum cephalosporins but not monobactams.
Ceftazidime and imipenem/meropenem resistant nonfermenting gram-negative bacilli isolated from various clinical specimens in 2001 and 2002 in Istanbul University, Istanbul Faculty of Medicine, Department of Microbiology and Clinical Microbiology were subjected to a PCR-aided rapid detection method with the blaIMP-1 and blaVIM-2 specific primers and the results were compared with those of two different double disk synergy tests and E-test metallo-ß-lactamase (E-test MBL) strips for detection of metallo-ß-lactamases.

Methods: Clinically isolated ceftazidime and imipenem/meropenem resistant nonfermenting gram-negative bacterial strains (75 P. aeruginosa and 25 Acinetobacter spp) were identified by conventional methods. Imipenem, meropenem, aztreonam and ceftazidime resistance was initially detected by the disk diffusion and the MICs of the antimicrobials by the agar dilution methods, and interpreted according to the recommendations of the NCCLS.

E Test MBL procedure: Mueller-Hinton agar was used for testing imipenem (IP) and imipenem+EDTA (IPI) (AB Biodisk, Solna, Sweden) containing E test MBL strips. The result was positive for MBL when the MIC ratio of IP/IPI was 8, showing three dilution decrease for the MIC of imipenem in the presence of EDTA.

Double disk synergy method: MBL production was detected by the ceftazidime/EDTA and ceftazidime/2-mercaptopropionic acid (MPA) disk synergy tests as descibed by Arakawa et al.

PCR method: PCR amplification was performed by using the following sets of primers for blaImp-1: IMP-1A (5´-ACC GCA GCA GAG TCT TTG C-3´) and IMP-1B (5´-ACA ACC AGT TTT GCC TTA CC-3´); and for blaVIM-2: VIM-1A (5´-ATT GGT CTA TTT GAC CGC GTC-3´) and VIM-2B (5´-TGC TAC TCA ACG ACT GAG CG-3´). A thermal cycler was used under the following conditions: initial denaturation at 94°C for 5 min; denaturation at 94°C for 60 s, annealing at 56°C for 45 s, and extension at 72°C for 60 s, repeated for 35 cycles; and final extension at 72°C for 7 min.

Results: The results are shown in table 1. By the PCR method, neither blaImp-1 nor blaVIM-2 was amplified in any of the isolates. MBL E-test strips (IP/IPI); CAZ/EDTA and CAZ/2-MPA disk synergy tests revealed that 44%, 53% and 61%, respectively, of the 75 P. aeruginosa but none of the 25 Acinetobacter spp isolates were MBL producers. The results obtained by the screening tests in P. aeruginosa isolates in the present study did not correlate with those obtained by PCR.

Comparison of different methods for detection of MBLs

Conclusion: E test and disk synergy results were not confirmed by PCR. If the EDTA and 2-MPA containing MBL-screening tests are accepted as reliable, MBL-specific and sensitive, then it may lead to the doubt that these isolates may have a different MBL.

P 17

SUSCEPTIBILITY OF CAMPYLOBACTER STRAINS TO MACROLIDES AND QUINOLONES

K. Ivanova, M. Marina, T. Ilieva
National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria

Macrolides and quinolones are drugs of choice for treatment of Campylobacter infections. Many authors reported an increase of the resistance to these antimicrobial agents in different countries from Europe and Asia.
The purpose of this study is to determine the susceptibility of Bulgarian Campylobacter strains to some macrolides and quinolones.
We studied the susceptibilities of 51 C. jejuni and C. coli strains to the following macrolides – erythromycin, josamycin, roxithromycin, clarithromycin, azithromycin and quinolones – ciprofloxacin, nalidixic acid and pefloxacin.
MIC was determined using the NCCLS-recommended agar dilution methods.
Azithromycin and roxithromycin proved to be the most effective compounds against Campylobacter: 90% of the strains inhibited at 0,5 µg/ml for azithromycin and at 4 µg/ml for roxithromycin. Josamycin and clarithromycin formed the intermediate group with 96% and 91% of susceptible strains at 8 µg/ml. Erythromycin had the lowest activity and the highest percent of resistant Campylobacter strains /11,5% at the same concentration.
Ciprofloxacin was more active than the rest of the drugs from its group – 94% of susceptible strains at 2 µg/ml, followed by pefloxacin – 88% of susceptible strains at 4 µg/ml. Nalidixic acid had the lowest activity – 71% of susceptible strains at 8 µg/ml.
There is a tendency of increasing resistance to erythromycin and nalidixic acid in our area. New macrolides and ciprofloxacin can be a good alternative for the treatment of severe campylobacteriosis.

P 18

CYSTIC FIBROSIS AND SENSITIVITY OF NON-FERMENTING GRAM-NEGATIVE BACTERIA

S. Alexiou-Daniel, A. Bisiklis, M. Chatzidimitriou, E. Tsiakiri, M. Fotoulaki, S. Nousia-Arvanitakis
Department of Microbiology, Fourth Department of Pediatrics, AHEPA University Hospital, School of Medicine, Thessaloniki, Greece

Purpose: The purpose of our study was to identify gram-negtive bacteria isolated from sputum cultures of patients with cystic fibrosis and to determine their antibiotic sensitivity.

Materials and methods: 107 strains of non-fermenting gram-negtive bacteria were isolated from the sputum of 30 patients during a six-month period in 2002 cultivated on MacConkey agar. The identification and determination of antibiotic sensitivity was performed by API 20 NE and VITEK (bioMérieux) respectively.

Results: The 107 bacterial strains were identified as follows: Ps. aeruginosa 49, Ps. fluorescens 24, Chryseomonas luteola 15, Burkholderia cepacia 6, Ps. stutzeri 5, Ps. putida 5, Ps. oryzihabitans 2, Alcaligenes xylosoxidans 1, Aeromonas hydrophila 1. The antibiotic sensitivity of the above mentioned gram-negtive strains was: Piperacillin/Tazobactam 83%, Meropenem 78%, Ticarcillin/CA 74%, Piperacillin 72%, Imipenem 73%, Ticarcillin 70%, Tobramycin 70%, Amikacin 66%, Cefepime 64%, Ciprofloxacin 57%, Aztreonam 50%, Netilmicin 47%, Cefpirome 47%, Trimethoprim/Sulfamethoxazole 38%, Ceftazidime 37%, Gentamicin 36%, Pefloxacin 29%.

Conclusion: a) 50% of the isolated gram-negtive strains were identified as Pseudomonas aeruginosa
b) Burkholderia cepacia were isolated in repeated sputum cultures of only one patient
c) Piperacillin/Tazobactam had the highest percentage sensitivity (83%)
d) Carbapenems, Meropenem and Imipenem appear to have a relevantly satisfying percentage of sensitivity.

P 19

ANTIBIOTICS SUSCEPTIBILITY OF ISOLATED BACTERIAL AGENTS IN HOSPITALIZED PATIENS

Y.O. Katashinskaya, V.I. Kresiun, P.N. Tchuev, O.Yu. Katashinsky, T.E. Opriatova, V.A. Pushkina, V.P. Lozitsky
Medical University, Odessa, Ukraine, State Clinical Hospital, Odessa, Ukraine, Ukrainian Research Anti-Plague Institute, Odessa, Ukraine

This investigation was carried out in the Odessa State Clinical Hospital during the second half of 2001 and whole 2002 years. The most of bacteriologically tested patients had post-operational complications. 56% isolated from 911 gram-negative cultures were sensitive to ceftazidime and 68% - to amicacin. 68% isolated from 261 gram-positive cultures were resistant to penicillin G and sensitive to ampicillin, vancomycin and nitrofurantoin in 85%, 82% and 98% of cases respectively. 56% from 667 Pseudomonas aeruginosa isolates were sensitive to ceftazidime and 68% - to amikacin. These agents demonstrated resistance to carbenicillin (65%) and gentamicin (69%). 228 Escherichia coli isolates were studied. 61% of them were resistant to ampicillin, 64% - to cephalothin and 65% - to tetracycline. 26 isolates from 31 studied in this respect were sensitive to ciprofloxacin. 198 isolates of Staphylococcus aureus were studied and they were resistant only to penicillin G (68%). Staphylococcus aureus was sensitive to erythromycin (67%), tetracycline (66%), oxacilline (76%) and vancomycine (80%). 98% from 62 Enterococcus faecalis isolates were sensitive to nitrofurantoin, 90% - to vancomycine, 91% - to chloramphenicol, 86% - to ampicillin and 77% - to ciprofloxacine. So, the majority of Staphylococcus aureus and Enterococcus faecalis isolates was susceptible to antibiotics, but the majority of Escherichia coli isolates was resistant to studied antibiotics expect ciprofloxacin. It is known that combine usage of antibiotics with proteolysis inhibitors (PI) may enhance their antibacterial activity. We had shown that PI para-aminomethylbenzoic acid increased efficacy of rifampicin and cefotaxim to Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and enhanced activity of cephalothin, linkamycin, ceftriaxon, chloramphenicol to last two bacterial agents.

P 20

EXTENDED-SPECTRUM BETA-LACTAMASE PRODUCING K. PNEUMONIAE FROM BACTEREMIA OUTBREAK AT SURGICAL INTENSIVE CARE UNIT

E. Keuleyan, S. Tete, T. Anakieva, R. Markovska
Medical Institute – Ministry of the Interior, Medical University, Sofia, Bulgaria

During February 2003 K. pneumoniae bacteremic episodes occurred in 3 patients admitted to SICU. The aim of this work is to report the microbiologic support in the epidemiologic investigation of the suspected outbreak.

Materials and methods: All isolates were detected by Bactec; the earliest time was at the 3.5 hour. Biochemical identification was by Crystal, BD. Susceptibility testing was according to NCCLS, 2002. Detection of ESBL was by DDS and NCCLS disk confirmatory test. Conjugation plasmid transfer was performed on a solid medium. IEF was according to Matthew/Bauernfeind and Bio-assay – by Bauernfeind.

Results: All isolates presented similar phenotype on antibiograme, suggesting for ESBL production through the positive DDS. ESBL was confirmed by the NCCLS method and positive mating. MICsCeftazidime were 128 mg/L; MICsCefotaxime – 8/16 mg/L; Sulbactam had inhibitory effect; the isolates were Aztreonam-resistant, Ceftibuten, Cefoxitin, Imipenem-susceptible. IEF identified an ESBL band of pI 8.2, suggesting SHV-type. For the epidemiological analysis, other specimens from patients, staff and environment were investigated. It was proposed that one of the bacteremic patients, who had been operated on emergency, discharged, then re-admitted, and from whose operative wound grew the same strain, represented the source of outbreak.

Conclusion: These results confirmed the hypothesis for a hospital outbreak with K. pneumoniae, ESBL-producer, identical SHV-type; and were important for both management of epidemics and therapy of infected patients.

P 21

EXTENDED SPECTRUM BETA-LACTAMASE PRODUCERS AMONG ENTEROBACTERIACEAE OF PATIENTS IN BULGARIAN HOSPITALS

R. Markovska, E. Keuleyan, M. Sredkova, D. Ivanova, E. Dragijeva, V. Genova, R. Gergova, I. Mitov
Chair of Microbiology, Medical University - Sofia; Chair of Microbiology, Medical University - Pleven; Queen Ioanna University Hospital - Sofia; Pediatric University Hospital - Sofia, Bulgaria

Objective: To discriminate the types of extended spectrum beta-lactamase (ESBL) among Bulgarian K. pneumoniae strains.

Methods: 59 K. pneumoniae strains identified as ESBL producers were collected from 6 medical centers in Sofia, Pleven and Stara Zagora during 1996-2002. They were confirmed by phenotypical tests (DDS, NCCLS confirmatory method, MIC, cefpodoxime disk, E test ESBL). MICs were determined by an agar dilution technique according to NCCLS, 2002 guidelines. Conjugative plasmid transfer was performed, followed by an isoelectric focusing in polyacrylamid gel. The procedure of Matthew et al. was modified (Bauernfeind et al.). The hydrolytic activity of the bands was proved by Bioassay (Bauernfeind et al).

Results: MIC of ceftazidime (CAZ) ranged from 1 mg/L to > 512 mg/L and of cefotaxime (CTX) - from 2 mg/L to 512 mg/L. The strains were divided into two main groups: The first one: MICCAZ was higher or equal to the MICCTX and the second one: MICCAZ is less than MICCTX. In all strains sulbactam in combination with ceftazidime and cefotaxime showed an inhibitory effect. Ceftazidime and/or cefotaxime resistance was transferable in 52 strains. Using IEF we grouped the strains with MICCAZ > MICCTX into two clusters.
One cluster of 31 strains demonstrated 3 different beta-lactamases with isoelectric points of 5.4 (TEM-type); 7.0-7.6 and 8.2 (SHV-type). Transconjugants from these strains on IEF had bands at 5.4 and 8.2. The bands at 8.2 hydrolysed CAZ. In this group 3 strains showed an additional beta-lactamase with band at 6.3 (TEM-type). Another cluster of 18 strains demonstrated beta-lactamases focusing between 6.3-6.5, which suggest TEM type. The strains with MICCAZ < MICCTX showed on IEF beta-lactamases with isoelectric points 5.4 (TEM) 7.0//7.6(SHV) and 8.8(CTX-M) (7 strains) or 8.4(CTX-M) (3 strains). The bands 8.4 and 8.8 hydrolyse CTX. The pI data were from transconjugants and wild type strains.

Conclusion: SHV type was dominating among Klebsiella in Bulgarian Hospitals. TEM type was proved in one hospital. CTX-M type (first determinate in 2001) showed a significant increase.

P 22

RESISTANCE OF SHIGELLA STRAINS TO ANTIBACTERIAL PREPARATIONS IN REPUBLIC BELARUS

V.M. Semenov, T.I. Dmitrachenko
Vitebsk State Medical University, Republic Belarus

Aim: To assess the resistance of shigella strains to antibacterial preparations.

Methods: The determination of antibiotic resistance was performed by serial dilutions method using Mueller-Hinton II broth and disk-diffusion method with the application of BBL disks produced by Becton Dickinson, USA. We have investigated 560 strains of Sh. sonnei and 439 strains of Sh. flexneri received from patients ill with shigellosis hospitalized to 7 hospitals of 4 regions of Republic Belarus. Results were analyzed using NCCLS standards.

Results: Sh. flexneri isolates were resistant to ampicillin (93.0%), chloramphenicol (81.8%), doxycyclin (63.8%), and furazolidon (70.6%). We have revealed high sensitivity of Shigella strains to cefalosporines of III generation, ciprofloxacin and polymyxin. The high resistance to inhibitor-protected ampicillin – ampicillin/sulbactam (75.0%) was found. Sh. sonnei strains showed the high levels of resistance to doxycyclin (84.1%) and co-trimoxazol (90.7%) only, and were highly sensitive to all other preparations applied. MIC90 among the strains of Sh. flexneri and Sh. sonnei differed significantly for such preparations as ampicillin, ampicillin/sulbactam, chloramphenicol, furazolidon, and were similar for doxycyclin, cefoperazon and ciprofloxacin. It was revealed 26 patterns of antibiotic resistance of Sh. flexneri strains, but only 3 of it were frequent: AM/SAM/SXT/D/CL (18.3%), AM/SAM/D/CL (27.1%) and AM/SAM/CL (18.0%). Sh. sonnei strains had 17 patterns of antibiotic resistance, and 63.4% of all isolates was of SXT/D phenotype.

Discussion: The revealed high levels of resistance to antibacterial preparations among widely-spreaded Shigella strains bring us to reconsiderate the recommended schemes of shigellosis therapy according to the regional levels of antibacterial resistance.

P 23

SEROTYPE DISTRIBUTION AND ANTIMICROBIAL RESISTANCE OF STREPTOCOCCUS PNEUMONIAE IN AUSTRIA, 1996 – 2002

A. Buxbaum, S. Forsthuber, Y. Gürol, W. Graninger, A. Georgopoulos
Department of Internal Medicine IV, Division of Pulmology, Department of Internal Medicine I, Division of Infectious Diseases and Chemotherapy, University of Vienna, Austria; Istanbul University, Istanbul Faculty of Medicine, Department of Microbiology and Clinical Microbiology, Turkey

Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide and is the most common cause of severe diseases like meningitis or CAP. In this study a total of 784 strains of S. pneumoniae was collected in an Austrian-wide surveillance system from 1996 to 2002. Isolates were tested on their susceptibility to penicillin, clarithromycin and azithromycin using the broth-microdilution method and serotyping was performed by the capsular swelling method. Overall, a rise in penicillin resistance could be observed from 5% in 1996 to approx. 10% in 2002 (including both intermediate-resistant and resistant strains). Also, a distinct rise in macrolide resistance was recorded in this period. The distribution of serotypes remained relatively stable with serotypes 23, 19, 6 and 14 being the most frequent ones. While in 1996 penicillin resistance was predominantly associated with serotype 23F, in 1998 serotype 9, and in 2002 serotype 14, was most frequently found in these resistant strains. Serotype 14 was also observed in the majority of cross-resistant pneumococci. This rise in the pneumococcal resistance against penicillin and the macrolides and the shift in serotype in these resistant strains clearly warrants ongoing surveillance programs in order to still be able to formulate an optimal antibiotic therapy in an era of ever-increasing resistance.

P 24

COMPARATIVE ACTIVITY OF TELITHROMYCIN AGAINST TYPICAL COMMUNITY-ACQUIRED RESPIRATORY PATHOGENS

A. Buxbaum, S. Forsthuber, W. Graninger, A. Georgopoulos
Department of Internal Medicine IV, Division of Pulmology, Department of Internal Medicine I, Division of Infectious Diseases and Chemotherapy, University of Vienna, Austria

Respiratory tract infections (RTIs) remain a significant cause of morbidity and mortality. Major bacterial pathogens in RTIs like S. pneumoniae have exhibited increasing resistance to a variety of antibiotics during the past decades. Telithromycin, the first ketolide, was specially designed to overcome this resistance. The present study was conducted to assess the comparative activity of telithromycin against typical RTI pathogens in Austria. A total of 832 bacterial isolates was tested, including S. pneumoniae, S. pyogenes, S. aureus and H. influenzae. MICs were determined using the NCCLS broth microdilution method for the following antimicrobials: penicillin G, ampicillin (for H. influenzae), azithromycin, clarithromycin, erythromycin A and telithromycin. Telithromycin showed excellent activity against S. pneumoniae with 99.8% of all isolates being sensitive. Penicillin remained active with MIC50 and MIC90 of 0.007 mg/l. Nevertheless, a notable increase in penicillin intermediate-resistant and resistant isolates from 4.9% in 1996 to the present rate of 10% could be observed. Also a distinct rise in the resistance levels of S. pneumoniae against the macrolides was recorded. All tested isolates of S. pyogenes were suceptible to penicillin and telithromycin and only low levels of resistance against telithromycin were found in S. aureus (2.2%, MIC90 of 0.5 mg/l). No telithromycin-resistant isolate of H. influenzae could be detected. This study demonstrates rising prevalence of resistance among S. pneumoniae not only to penicillin but also to other antimicrobials. It also shows the value of telithromycin as an attractive option for the empirical treatment of community-aquired RTIs in an era of wide-spread antibacterial resistance.