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R2166 Tigecycline in vitro activity against carbapenem-non-susceptible Acinetobacter baumannii
New antimicrobials
Amikacin Amox/Clav Ampicillin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Minocycline Pip/Tazo Tig
S627
E. coli/Kleb n = 439
Enterobacter n = 205
Acinetobacter n = 116
4 32 >32 4 8 16 0.5 8 8 16 0.5
2 >32 >32 2 32 32 1 0.25 4 32 1
>64 >32 >32 >32 >32 >64 >16 >8 16 >128 1
Results: The tables summarise results for all isolates, and for specific key pathogens. Conclusions: Tig had the lowest MIC90 vs. Gram-positive strains (incl. MRSA, PRSP), and was essentially as active as imipenem vs. Gramnegative strains (incl. ESBL+). It was also significantly more active than any comparators (other than linezolid) vs. enterococci and Acinetobacter. R2166 Tigecycline in vitro activity against carbapenem-nonsusceptible Acinetobacter baumannii J. Komarnicka, L. Naumiuk, A. Samet (Gdansk, PL) Objectives: To evaluate tigecycline activity against carbapenem-resistant and carbapenem intermediate susceptible Acinetobacter baumannii isolated from patients of a university hospital in Poland. Methods: Twenty two multidrug-resistant A. baumannii isolates which were non-susceptible to carbapenems by disk-diffusion method were selected for tigecycline activity determination. MICs to tigecycline (TGC), imipenem (IMP) and meropenem (MEM) were determined by E test. EUCAST Enterobacteriaceae TGC susceptibility/resistance breakpoints were used due to lack of official Acinetobacter specific breakpoints and were as follows: susceptible 1 and resistant >2 mg/L. Results: Eleven isolates were intermediate susceptible to TGC (MIC from 1.5 to 2 mg/L), 10 were susceptible (MIC from 0.016 to 1 mg/L) and 1 was resistant (MIC=4 mg/L) according to choosen breakpoints. In 13 isolates resistant to both IMP and MEM (MIC 16 mg/L) TGC retained full activity in only 4, further 9 isolates remained intermediate susceptible to TGC. There were 6 isolates with IMP-I and MEM-R phenotype, five of them were susceptible to TGC and one was intermediate. Each of 3 isolates which had IMP-I and MEM-I phenotype, displayed different TGC phenotype: resistant, intermediate and susceptible. Conclusion: TGC was only partially active against carbapenem nonsusceptible A. baumannii in our hospital. The lowest TGC activity was noted among isolates resistant to both IMP and MEM. TGC remains an interesting alternative in treating multidrug-resistant Acinetobacter but demands antimicrobial susceptibility testing in every case. R2167 Antimicrobial susceptibility to third and fourth generation cephalosporins and the prevalence of extended-spectrum b-lactamase-producing isolates among Enterobacteriaceae from different clinical specimens B. Kocic, S. Mladenovic-Antic, G. Randjelovic, P. Stojanovic, M. Dinic (Niˇs, RS) Infections that are caused by multiple antibiotic resistant organisms cause significant morbidity and mortality. ESBL-producing aerobic Gramnegative rods are resistant to first, second and the third generation cephalosporins and penicilins, and may show simultaneous resistance
to fluoroquinolones and aminoglicosides. They have rapidly emerged as major pathogens around the world, and have compromised therapy with b-lactam antibiotics, including third generation cephalosporins. Objectives: To evaluate the antimicrobial susceptibility to third and fourth generation cephalosporins, and to comprise the frequency of ESBL-producing strains among the most common Gram negative rods collected from different clinical specimens from the Institute for Public Health in Niˇs during the year 2005. Methods: 1112 strains of Enterobacteriaceae were studied. Their antimicrobial susceptibility was tested by the disk-diffusion method according the CLSI guidelines. Screening for the detection for ESBL from Enterobacteriaceae was carried out by the double-disk sinergy test (DDST). The E-test ESBL was used as a confirmation test. Results: The species distribution as follow: E. coli 449 (40.02%), Enterobacter spp. 215 (19.16%), Klebsiella spp. 161 (14.35%), Proteus mirabilis 142 (12.66%), Morganella morganii 39 (3.48%), Citrobacter sp. 39 (3.48%), Providencia spp. 19 (1.69%), Proteus vulgaris 18 (1.6%). Antimicrobial resistance to b-lactam antibiotics was: to amoxicillin clavulanic acid 60%, to ceftazidime 57.1%, to ceftriaksone 47.1%, to cefotaksime 40.7%, and to cefepime 47.7%. ESBL production was observed in 17.8% of all the isolates. The highest rates were for Klebsiella spp.33%, E. coli 19.1% and Enterobacter spp. 27.4%. Seventy five percent of ESBL-positive strains were nosocomial. Conclusion: In our country, most of the investigated strains showed high rates of resistance to third and fourth generation cephalosporins. In addition, we have found an increase in the ESBL-positive strains of Enterobacteriaceae, from 15.79% in 2002. to 17.8% in 2005.
New antimicrobials R2168 Anti-giardial activity of phenolic essential oils C. Cavaleiro, B. Gaspar, L. Salgueiro, J. Poiares-da-Silva, M.C. Sousa (Coimbra, PT) Giardia lamblia, a parasitic flagellated protozoan, is the most common causative agent of diarrhoeal illness world-wide. Current therapy against G. lamblia infection (giardiasis) is unsatisfactory due to high incidence of undesirable side effects and a significant failure in clearing parasites from the gastrointestinal tract. Because of these problems, new compounds are being screened for antigiardial activity, namely plant extracts. Aromatic plants and their essential oils, mixtures of natural volatile compounds isolated by distillation, have been used since antiquity to heal microbial infections. Previous works showed that several essential oils showed important antibacterial, antifungal and antiparasitic activity, predicting therapeutic benefits on diseases involving gastrointestinal, mucosal, cutaneous and respiratory infections. In the present work, we study the effect of essential oils obtained from several aromatic plants (Thymus zygis ssp. sylvestris, T. pulegioides, Thymbra capitata, Origanum virens and Lippia graveolens Thymus capitelatus, Thymus mastichina, Mentha cervina and Mentha piperita) on G. lamblia growth. Essential oils were obtained by hydrodistillation from fresh plant material and analysed by GC and GC-MS. Constituents were identified from their retention indices on two different phases GC columns (polydimethylsiloxane and polyethyleneglycol) and from their mass spectra, which were compared with reference data. Culture trophozoites of WB strain (ATCC 30957) were incubated in growth medium with different concentrations of essential oils for 48 h at 37ºC under anaerobic conditions. The inhibitory concentration (IC50) values were determined by cell counting. The plant activities were compared with metronidazol activity, considered a “gold standard” antibiotic used in therapy of giardiasis. Oils from plants with non-phenolic compositions did not revealed anti-giardial activity. Contrarily, essentials oils from Thymus zygis ssp. sylvestris, Thymus pulegioides, Thymbra capitata, Origanum virens and Lippia graveolens inhibited trophozoites growth and were classified as “active”. The IC50 values range from 0.07 microL/mL to 0.15 microL/mL. The compositions of these active oils are characterised
Amikacin Amox/Clav Ampicillin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Minocycline Pip/Tazo Tig
S627
E. coli/Kleb n = 439
Enterobacter n = 205
Acinetobacter n = 116
4 32 >32 4 8 16 0.5 8 8 16 0.5
2 >32 >32 2 32 32 1 0.25 4 32 1
>64 >32 >32 >32 >32 >64 >16 >8 16 >128 1
Results: The tables summarise results for all isolates, and for specific key pathogens. Conclusions: Tig had the lowest MIC90 vs. Gram-positive strains (incl. MRSA, PRSP), and was essentially as active as imipenem vs. Gramnegative strains (incl. ESBL+). It was also significantly more active than any comparators (other than linezolid) vs. enterococci and Acinetobacter. R2166 Tigecycline in vitro activity against carbapenem-nonsusceptible Acinetobacter baumannii J. Komarnicka, L. Naumiuk, A. Samet (Gdansk, PL) Objectives: To evaluate tigecycline activity against carbapenem-resistant and carbapenem intermediate susceptible Acinetobacter baumannii isolated from patients of a university hospital in Poland. Methods: Twenty two multidrug-resistant A. baumannii isolates which were non-susceptible to carbapenems by disk-diffusion method were selected for tigecycline activity determination. MICs to tigecycline (TGC), imipenem (IMP) and meropenem (MEM) were determined by E test. EUCAST Enterobacteriaceae TGC susceptibility/resistance breakpoints were used due to lack of official Acinetobacter specific breakpoints and were as follows: susceptible 1 and resistant >2 mg/L. Results: Eleven isolates were intermediate susceptible to TGC (MIC from 1.5 to 2 mg/L), 10 were susceptible (MIC from 0.016 to 1 mg/L) and 1 was resistant (MIC=4 mg/L) according to choosen breakpoints. In 13 isolates resistant to both IMP and MEM (MIC 16 mg/L) TGC retained full activity in only 4, further 9 isolates remained intermediate susceptible to TGC. There were 6 isolates with IMP-I and MEM-R phenotype, five of them were susceptible to TGC and one was intermediate. Each of 3 isolates which had IMP-I and MEM-I phenotype, displayed different TGC phenotype: resistant, intermediate and susceptible. Conclusion: TGC was only partially active against carbapenem nonsusceptible A. baumannii in our hospital. The lowest TGC activity was noted among isolates resistant to both IMP and MEM. TGC remains an interesting alternative in treating multidrug-resistant Acinetobacter but demands antimicrobial susceptibility testing in every case. R2167 Antimicrobial susceptibility to third and fourth generation cephalosporins and the prevalence of extended-spectrum b-lactamase-producing isolates among Enterobacteriaceae from different clinical specimens B. Kocic, S. Mladenovic-Antic, G. Randjelovic, P. Stojanovic, M. Dinic (Niˇs, RS) Infections that are caused by multiple antibiotic resistant organisms cause significant morbidity and mortality. ESBL-producing aerobic Gramnegative rods are resistant to first, second and the third generation cephalosporins and penicilins, and may show simultaneous resistance
to fluoroquinolones and aminoglicosides. They have rapidly emerged as major pathogens around the world, and have compromised therapy with b-lactam antibiotics, including third generation cephalosporins. Objectives: To evaluate the antimicrobial susceptibility to third and fourth generation cephalosporins, and to comprise the frequency of ESBL-producing strains among the most common Gram negative rods collected from different clinical specimens from the Institute for Public Health in Niˇs during the year 2005. Methods: 1112 strains of Enterobacteriaceae were studied. Their antimicrobial susceptibility was tested by the disk-diffusion method according the CLSI guidelines. Screening for the detection for ESBL from Enterobacteriaceae was carried out by the double-disk sinergy test (DDST). The E-test ESBL was used as a confirmation test. Results: The species distribution as follow: E. coli 449 (40.02%), Enterobacter spp. 215 (19.16%), Klebsiella spp. 161 (14.35%), Proteus mirabilis 142 (12.66%), Morganella morganii 39 (3.48%), Citrobacter sp. 39 (3.48%), Providencia spp. 19 (1.69%), Proteus vulgaris 18 (1.6%). Antimicrobial resistance to b-lactam antibiotics was: to amoxicillin clavulanic acid 60%, to ceftazidime 57.1%, to ceftriaksone 47.1%, to cefotaksime 40.7%, and to cefepime 47.7%. ESBL production was observed in 17.8% of all the isolates. The highest rates were for Klebsiella spp.33%, E. coli 19.1% and Enterobacter spp. 27.4%. Seventy five percent of ESBL-positive strains were nosocomial. Conclusion: In our country, most of the investigated strains showed high rates of resistance to third and fourth generation cephalosporins. In addition, we have found an increase in the ESBL-positive strains of Enterobacteriaceae, from 15.79% in 2002. to 17.8% in 2005.
New antimicrobials R2168 Anti-giardial activity of phenolic essential oils C. Cavaleiro, B. Gaspar, L. Salgueiro, J. Poiares-da-Silva, M.C. Sousa (Coimbra, PT) Giardia lamblia, a parasitic flagellated protozoan, is the most common causative agent of diarrhoeal illness world-wide. Current therapy against G. lamblia infection (giardiasis) is unsatisfactory due to high incidence of undesirable side effects and a significant failure in clearing parasites from the gastrointestinal tract. Because of these problems, new compounds are being screened for antigiardial activity, namely plant extracts. Aromatic plants and their essential oils, mixtures of natural volatile compounds isolated by distillation, have been used since antiquity to heal microbial infections. Previous works showed that several essential oils showed important antibacterial, antifungal and antiparasitic activity, predicting therapeutic benefits on diseases involving gastrointestinal, mucosal, cutaneous and respiratory infections. In the present work, we study the effect of essential oils obtained from several aromatic plants (Thymus zygis ssp. sylvestris, T. pulegioides, Thymbra capitata, Origanum virens and Lippia graveolens Thymus capitelatus, Thymus mastichina, Mentha cervina and Mentha piperita) on G. lamblia growth. Essential oils were obtained by hydrodistillation from fresh plant material and analysed by GC and GC-MS. Constituents were identified from their retention indices on two different phases GC columns (polydimethylsiloxane and polyethyleneglycol) and from their mass spectra, which were compared with reference data. Culture trophozoites of WB strain (ATCC 30957) were incubated in growth medium with different concentrations of essential oils for 48 h at 37ºC under anaerobic conditions. The inhibitory concentration (IC50) values were determined by cell counting. The plant activities were compared with metronidazol activity, considered a “gold standard” antibiotic used in therapy of giardiasis. Oils from plants with non-phenolic compositions did not revealed anti-giardial activity. Contrarily, essentials oils from Thymus zygis ssp. sylvestris, Thymus pulegioides, Thymbra capitata, Origanum virens and Lippia graveolens inhibited trophozoites growth and were classified as “active”. The IC50 values range from 0.07 microL/mL to 0.15 microL/mL. The compositions of these active oils are characterised