101 results on '"Tassios PT"'
Search Results
2. Resistance to beta-lactams among blood isolates of Salmonella spp. in European hospitals: results from the SENTRY Antimicrobial Surveillance Program 1997-98
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Tzouvelekis, LS, Lukova, [No Value], Tassios, PT, Fluit, AC, Jones, RN, Legakis, NJ, and University of Groningen
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resistance ,SPECTRUM ,REDUCED SUSCEPTIBILITY ,Salmonella ,beta-lactams ,polycyclic compounds ,biochemical phenomena, metabolism, and nutrition ,FREQUENCY ,SEROTYPE TYPHIMURIUM - Abstract
The susceptibility to beta -lactams and the beta -lactamase content of 110 Salmonella spp. blood isolates collected during 1997-98 in 19 European centers participating in the SENTRY Surveillance Program were studied. Thirty-one isolates (28%) were resistant to penicillins, due to production of TEM-1 (27 isolates), OXA-1 (three isolates) or TEM-1 + OXA-1 (one isolate). All OXA-1 producers and 10 TEM-1-producing isolates were also resistant to penicillin-clavulanic acid combinations. In the latter isolates, this phenotype was associated with increased production of TEM-1. Sixteen TEM-1-producing Salmonella Enteritidis isolates and one OXA-1-producing S. Typhimurium isolate were able to transfer beta -lactam resistance by conjugation.
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- 2003
3. Multiresistant Acinetobacter baumannii isolates in intensive care units in Greece
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Maniatis, AN Pournaras, S Orkopoulou, S Tassios, PT and Legakis, NJ
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One hundred and twenty-one clinical isolates of Acinetobacter baumannii recovered from the intensive care units (ICUs) of nine tertiary-care hospitals in Athens, Greece were studied in order to determine whether the increasing appearance of resistant acinetobacters is due to the spread of epidemic strains. The majority of the isolates exhibited resistance to ampicillin-sulbactam, and the most common antibiotic resistance profiles comprised resistance to nine and eight of the 11 potentially active antibiotics tested, respectively. Pulsed-field gel electrophoresis showed that 68% of the isolates, recovered from all ICUs, belonged to two clonal groups, indicating inter-hospital dissemination of multiresistant A. baumannii in our region.
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- 2003
4. Predominance of two M-types among erythromycin-resistant group A Streptococci from Greek children
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Zachariadou, L Papaparaskevas, J Paraskakis, I Efstratiou, A and Pangalis, A Legakis, NJ Tassios, PT
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In order to investigate the potential relationship between erythromycin resistance and specific M-serotypes among clinical isolates of Streptococcus pyogenes from children in Greece, we randomly selected a total of 49 erythromycin-resistant (EryR) and 21 erythromycin-susceptible (EryS) isolates from the 1158 S. pyogenes isolates from the two main children’s hospitals of Athens during the period October 1997 to October 1998. The isolates were further characterized by M-serotyping, examined for their susceptibility to penicillin, vancomycin and clindamycin, and categorized into resistance phenotypes. A total of 248 (21%) S. pyogenes isolates in the two main children’s hospitals of Athens during the study period were resistant to erythromycin. All 49 EryR and 21 EryS isolates were susceptible to penicillin and vancomycin. With respect to erythromycin and clindamycin resistance, phenotypes M and IR MLSB dominated, with 30 and 17 isolates, respectively, two isolates belonged to the CR MLSB phenotype. Among the erythromycin resistant isolates, two M serotypes were dominant: M22 (30%) and M84 (41%). More specifically, M22 and M84 were most prevalent in resistance phenotypes IR MLSB (65%) and M (63%), respectively. In the susceptible group, no isolate belonged to these two M-serotypes, nor was a predominant serotype found. In contrast to susceptible isolates, two distinct M-serotypes were highly represented among EryR S. pyogenes isolates and predominantly associated with two distinct phenotypes.
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- 2003
5. Harmonization of pulsed-field gel electrophoresis protocols for epidemiological typing of strains of methicillin-resistant Staphylococcus aureus: a single approach developed by consensus in 10 European laboratories and its application for tracing the spread of related strains
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Murchan, S Kaufmann, ME Deplano, A de Ryck, R Struelens, M Zinn, CE Fussing, V Salmenlinna, S Vuopio-Varkila, J and El Solh, N Cuny, C Witte, W Tassios, PT Legakis, N and van Leeuwen, W van Belkum, A Vindel, A Laconcha, I and Garaizar, J Haeggman, S Olsson-Liljequist, B Ransjo, U and Coombes, G Cookson, B
- Abstract
Pulsed-field gel electrophoresis (PFGE) is the most common genotypic method used in reference and clinical laboratories for typing methicillin-resistant Staphylococcus aureus (MRSA). Many different protocols have been developed in laboratories that have extensive experience with the technique and have established national databases. However, the comparabilities of the different European PFGE protocols for MRSA and of the various national MRSA clones themselves had not been addressed until now. This multinational European Union (EU) project has established for the first time a European database of representative epidemic MRSA (EMRSA) strains and has compared them by using a new “harmonized” PFGE protocol developed by a consensus approach that has demonstrated sufficient reproducibility to allow the successful comparison of pulsed-field gels between laboratories and the tracking of strains around the EU. In-house protocols from 10 laboratories in eight European countries were compared by each center with a “gold standard” or initial harmonized protocol in which many of the parameters had been standardized. The group found that it was not important to standardize some elements of the protocol, such as the type of agarose, DNA block preparation, and plug digestion. Other elements were shown to be critical, namely, a standard gel volume and concentration of agarose, the DNA concentration in the plug, the ionic strength and volume of running buffer used, the running temperature, the voltage, and the switching times of electrophoresis. A new harmonized protocol was agreed on, further modified in a pilot study in two laboratories, and finally tested by all others. Seven laboratories’ gels were found to be of sufficiently good quality to allow comparison of the strains by using a computer software program, while two gels could not be analyzed because of inadequate destaining and DNA overloading. Good-quality gels and inclusion of an internal quality control strain are essential before attempting intercenter PFGE comparisons. A number of clonally related strains have been shown to be present in multiple countries throughout Europe. The well-known Iberian clone has been demonstrated in Belgium, Finland, France, Germany, and Spain (and from the wider HARMONY collection in Portugal, Slovenia, and Sweden). Strains from the United Kingdom (EMRSA-15 and -16) have been identified in several other countries, and other clonally related strains have also been identified. This highlights the need for closer international collaboration to monitor the spread of current epidemic strains as well as the emergence of new ones.
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- 2003
6. Prevalence and characterization of the mechanisms of macrolide, lincosamide and streptogramin resistance in viridans group streptococci
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Ioannidou, S Papaparaskevas, J Tassios, PT Foustoukou, M and Legakis, NJ Vatopoulos, AC
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The presence of erm genes conferring constitutive and inducible resistance, as well as that of the mefA gene conferring only constitutive resistance, was investigated using PCR in 70 erythromycin resistant (MIC greater than or equal to 1 mg/l) strains of viridans group streptococci (VGS) (18 Streptococcus mitis biotype 1, 16 S. mitis biotype 2, 15 S. oralis, 12 S. salivarius and nine S. sanguis) isolated from the oropharynx of healthy Greek children. All of the 56 isolates belonging to resistance phenotype M harbored the mefA gene. All of the 14 isolates constitutively resistant to macrolides and lincosamides (phenotype CR) harbored the ermB gene. Co-presence of both genes was not observed, whereas class A erm gene (previously known as ermTR) was not detected. Our results are consistent with a possible role of VGS as a reservoir of resistance genes now prevalent in pathogenic species of streptococci. (C) 2003 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.
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- 2003
7. In vitro activity of telithromycin (HMR 3647) against Greek Streptococcus pyogenes and Streptococcus pneumoniae clinical isolates with different macrolide susceptibilities
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Ioannidou, S Tassios, PT Zachariadou, L Salem, Z and Kanelopoulou, M Kanavaki, S Chronopoulou, G Petropoulou, N and Foustoukou, M Pangalis, A Trikka-Graphakos, E and Papafraggas, E Vatopoulos, AC
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education ,polycyclic compounds ,biochemical phenomena, metabolism, and nutrition - Abstract
The susceptibilities to macrolides and telithromycin of 161 Streptococcus pyogenes and 145 Streptococcus pyogenes strains, consecutively isolated from five Greek hospitals, were determined by Etest. Moreover, mechanisms of resistance to macrolides were phenotypically and genetically determined by double disk induction test and PCR, respectively. Of the S. pneumoniae and S. pyogenes isolates, 42.8% and 30.8%, respectively, were found to be resistant to erythromycin. Of the erythromycin-resistant S. pneumoniae and S. pyogenes isolates, 57.5% and 59.5%, respectively, displayed the M phenotype and harbored the mefA/E gene. Telithromycin was found to be more active than both erythromycin and clarithromycin against both species, with considerably lower MIC50 and MIC90 values.
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- 2003
8. A common clone of erythromycin-resistant Streptococcus pneumoniae in Greece and the UK
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Fotopoulou, N Tassios, PT Beste, DV Ioannidou, S and Efstratiou, A Lawrence, ER Papaparaskevas, J George, RC and Legakis, NJ
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Objective To investigate the possible genetic relationship among erythromycin-resistant Streptococcus pneumoniae strains isolated in Greece and the UK. Methods During 1995-97,140 S. pneumoniae strains were isolated from clinical specimens submitted to the microbiology departments of the two main children’s hospital in Athens. All erythromycin-resistant strains were further studied with respect to the presence of genes encoding for the two major mechanisms of macrolide resistance, their serotypes, and pulsed-field gel electrophoresis (PFGE) types, in comparison to a previously characterized UK erythromycin-resistant clone. Results Eleven of the 140 isolates (7.9%) were resistant to erythromycin; nine of these were susceptible to penicillin. Serotyping allocated seven, three and one isolates to serotypes 14, 19F and serogroup 6, respectively. The mefA gene was detected in seven isolates (five serotype 14 and two serotype 19F), ermB in two (one serotype 19F and the serogroup 6 isolate), whilst in the remaining two isolates no resistance gene could be detected by polymerase chain reaction (PCR). Pulsed-field gel electrophoresis of genomic DNA showed that five Greek serotype 14 isolates belonged to the same chromosomal type as the serotype 14 erythromycin-resistant UK clone. Conclusions The present study showed that erythromycin resistance among the S. pneumoniae isolates was mostly owing to the efflux mechanism and suggested a possible clonal spread of serotype 14 erythromycin-resistant S. pneumoniae strains between Greece and the UK.
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- 2003
9. Infrequent detection of acquired metallo-beta-lactamases among carbapenem-resistant Pseudomonas isolates in a Greek hospital
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Tsakris, A Tassios, PT Polydorou, F Papa, A Malaka, E and Antoniadis, A Legakis, NJ
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polycyclic compounds ,bacteria ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses - Abstract
Objective To study the possible distribution of metallo-beta-lactamases among nosocomial Pseudomonas isolates in a Greek hospital with a recent high prevalence of carbapenem-resistant Pseudomonas isolates. Methods All carbapenem-resistant (imipenem- and/or meropenem-resistant) (MICS > 8 mg/L) Pseudomonas non-replicate isolates recovered from clinical infections in the Microbiology Laboratory of Saint Demetrios Hospital, Thessaloniki, Greece, from April 1998 to November 2000 were studied for the presence of metallo-beta-lactamases. They were tested by a disk diffusion test, PCR analysis, and nucleotide sequencing. DNA fingerprints were obtained by pulsed-field gel electrophoresis (PFGE) of XbaI-digested chromosomal DNA. Results In total, 24 carbapenem-resistant isolates (23 P. aeruginosa and one P. putida) were recovered. The serotypes observed among the P. aeruginosa isolates were, in order of decreasing frequency, O:11 (52%), O:3 and O:12 (17% each), and O:6 (13%). PFGE grouped 17 of the P. aeruginosa isolates into four clusters, each containing from two to seven isolates while the remaining isolates exhibited unique genotypes. bla(VIM-2) was detected in the P. putida isolate and a P. aeruginosa serotype 0:3 isolate. The latter strain was genotypically distinct from other contemporaneous or older carbapenem-resistant P. aeruginosa Greek isolates. Conclusion These findings suggest that, although the prevalence of metallo-beta-lactamases is low, the integron-associated bla(VIM) genes can spread to P. aeruginosa serotypes that have not been previously associated with carbapenem resistance in our region, as well as to other pseudomonal species.
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- 2003
10. Multidrug and broad-spectrum cephalosporin resistance among Salmonella enterica serotype enteritidis clinical isolates in southern Italy
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Villa, L Mammina, C Miriagou, V Tzouvelekis, LS Tassios, PT Nastasi, A Carattoli, A
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polycyclic compounds ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses - Abstract
From 1992 to 1997, only six sporadic isolates of Salmonella enterica serotype Enteritidis from patients with cases of gastroenteritis in southern Italy exhibited resistance to broad-spectrum cephalosporins. Five isolates produced SHV-12, and one isolate encoded a class C beta-lactamase. The bla(SHV-12) gene was located in at least two different self-transferable plasmids, one of which also carried a novel class 1 integron.
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- 2002
11. Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a neonatal intensive care unit in the high-prevalence area of Athens, Greece
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Lebessi, E Dellagrammaticas, H Tassios, PT Tzouvelekis, LS and Ioannidou, S Foustoukou, M Legakis, NJ
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Extended-spectrum P-lactamase-producing Klebsiella pneumoniae (EPKP) strains are frequently implicated in outbreaks in neonatal intensive care units (NICUs). During the period from 1997 to 1998, 21 infections and 23 colonizations with EPKP were recorded in the NICU of a children’s hospital in Athens, Greece. Seventeen of the infected and 12 of the colonized neonates had been referred from other hospitals. The remaining infections and colonizations occurred during the current hospitalization. Pulsed-field gel electrophoresis typing showed that the latter cases were due to an outbreak strain that persisted in the unit, while the repeated introduction of EPKP carriers was mostly due to clonal outbreaks in two maternity hospitals.
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- 2002
12. Epidemiology of multiresistant Enterococcus avium isolates in a Greek tertiary care hospital
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Papaparaskevas, J Tassios, PT Kalapothaki, V Avlami, A and Legakis, NJ Vatopoulos, AC
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biochemical phenomena, metabolism, and nutrition - Abstract
A retrospective survey of the isolation rate of Enterococcus avium during the period March 1994-February 2000 conducted in Laikon General Hospital using the WHONET software, revealed a peak in the isolation rates of this species during March 1995-February 1996. The ten strains isolated during this time were studied further. No glycopeptide resistance was detected but resistance to ampicillin, ciprofloxacin, erythromycin, gentamicin (high-level) and streptomycin (high-level) was present in nine, ten, nine, three and seven of the isolates, respectively. The genes aac(6’)-Ie+aph(2”)-Ia and ant(6)-I, encoding for high-level gentamicin and streptomycin resistance, respectively, were detected only in the isolates with the corresponding phenotypes. Beta-lactamase production and haemolysis were not detected. There was evidence of ward-, floor- and building-specific distribution among the different aminoglycoside resistance phenotypes. DNA fingerprinting by PFGE grouped six of the ten isolates in a single cluster with 83% similarity, even though they expressed various resistance phenotypes. These results suggest dissemination of resistance genes among both genetically related and unrelated strains. (C) 2002 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.
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- 2002
13. Antibiotic resistance rates and macrolide resistance phenotypes of viridans group streptococci from the oropharynx of healthy Greek children
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Ioannidou, S Tassios, PT Kotsovili-Tseleni, A Foustoukou, M and Legakis, NJ Vatopoulos, A
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A total of 200 isolates of viridans group streptococci isolated from the oropharynx of healthy Greek children were studied. Vancomycin, rifampicin, fluoroquinolones and dalfopristin/quinupristin were active against all tested isolates. High level resistance to gentamicin was not seen. Intermediate and high-level penicillin resistance was present in 28.5 and 14.5% isolates, respectively. with 41.3% of the latter group, being also resistant to cefotaxime. Resistance rates to other antimicrobials were as follows - erythromycin 38.5%, clarithromycin 33.5%, clindamycin 7.5% and tetracycline 23%. Penicillin resistance occurred more frequently in Streptococcus mitis isolates, while macrolide resistance was more frequent in S. oralis. MLSB resistance phenotype M was dominant (74%) among erythromycin resistant isolates, with phenotypes IR and CR being represented by 6 and 20% of isolates, respectively. (C) 2001 Elsevier Science B.V. and International Society of Chemotherapy All rights reserved.
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- 2001
14. Multicenter evaluation of epidemiological typing of methicillin-resistant Staphylococcus aureus strains by repetitive-element PCR analysis
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Deplano, A Schuermans, A van Eldere, J Witte, W and Meugnier, H Etienne, J Grundmann, H Jonas, D Noordhoek, GT Dijkstra, J van Belkum, A van Leeuwen, W Tassios, PT and Legakis, NJ van der Zee, A Bergmans, A Blanc, DS and Tenover, FC Cookson, BC O'Neil, G Struelens, MJ European Study Grp Epidemiological
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biochemical phenomena, metabolism, and nutrition - Abstract
Rapid and efficient epidemiologic typing systems would be useful to monitor transmission of methicillin-resistant Staphylococcus aureus (MRSA) at both local and interregional levels. To evaluate the intralaboratory performance and interlaboratory reproducibility of three recently developed repeat-element PCR (rep-PCR) methods for the typing of MRSA, 50 MRSA strains characterized by pulsed-field gel electrophoresis (PFGE) (SmaI) analysis and epidemiological data were blindly typed by inter-IS256, 16S-23S ribosomal DNA (rDNA), and MP3 PCR in 12 laboratories in eight countries using standard reagents and protocols. Performance of typing was defined by reproducibility (R), discriminatory power (D), and agreement with PFGE analysis. Interlaboratory reproducibility of pattern and type classification was assessed visually and using gel analysis software. Each typing method shelved a different performance level in each center. In the center performing best with each method, inter-IS256 PCR typing achieved R = 100% and D = 100%; 16S-23S rDNA PCR, R = 100% and D = 82%; and MP3 PCR, R = 80% and D = 83%. Concordance between rep-PCR type and PFGE type ranged by center: 70 to 90% for inter-IS256 PCR, 44 to 57% for 16S-23S rDNA PCR, and 53 to 54% for MP3 PCR analysis. In conclusion, the performance of inter-IS256 PCR typing was similar to that of PFGE analysis in some but not all centers, whereas other rep-PCR protocols showed lower discrimination and intralaboratory reproducibility. None of these assays, however, was sufficiently reproducible for interlaboratory exchange of data.
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- 2000
15. Multiple clones within multidrug-resistant Salmonella enterica serotype typhimurium phage type DT104
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Markogiannakis, A Tassios, PT Lambiri, M Ward, LR and Kourea-Kremastinou, J Legakis, NJ Vatopoulos, AC Greek Nontyphoidal Salmonella Stud
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biochemical phenomena, metabolism, and nutrition - Abstract
Six distinct clones were present among Greek multidrug-resistant Salmonella enterica serotype Typhimurium phage type DT104, since isolates belonging to resistance phenotypes including the ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline) core could be distinguished with respect to their pulsed-field gel electrophoresis patterns, int1 integron structures, and presence or absence of antibiotic resistance genes ant(3”)-Ia, pse-1, and tem-1.
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- 2000
16. Serotype, biotype and genomic DNA Xbal restriction fragment analysis of Yevsinia enterocolitica, isolated from infected beta-thalassemic and nonthalassemic children in Greece
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Kyriazi, Z Chatzipanagiotou, S Trikka-Graphakos, E Legakis, NJ Tassios, PT
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- 2000
17. Extended spectrum beta-lactamases in salmonella strains isolated in Austria
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Lukova, V Tzouvelekis, LS Tassios, PT Thiel, W
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- 2000
18. Characterization of Neisseria gonorrhoeae strains with decreased susceptibility to fluoroquinolones isolated in Greece from 1996 to 1999
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Mavroidi, A Tzouvelekis, LS Tassios, PT Flemetakis, A and Daniilidou, M Tzelepi, E
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Of the 331 Neisseria gonorrhoeae strains isolated in Greece from 1996 to 1999, 39 (11.8%) exhibited decreased susceptibility to quinolones due to gyrA and parC mutations. Conventional typing and pulsed-field gel electrophoresis showed that 34 of these isolates were clonally related. Epidemiological data indicated that the epidemic clone was sustained in a group of high-frequency transmitters.
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- 2000
19. CTX-M-type beta-lactamases: an emerging group of extended-spectrum enzymes
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Tzouvelekis, LS Tzelepi, E Tassios, PT Legakis, NJ
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polycyclic compounds ,bacteria ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses - Abstract
CTX-M-type beta-lactamases constitute a novel group of class A beta-lactamases with extended-spectrum properties. They are encoded by transferable plasmids and found in various enterobacteria, mostly Salmonella typhimurium, Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis. CTX-M enzymes share extensive sequence similarity with the chromosomal beta-lactamases of Klebsiella oxytoca. They efficiently hydrolyze many newer broad-spectrum oximino-beta-lactams including cefotaxime, ceftriaxone and aztreonam and are readily inhibited by tazobactam and clavulanate. CTX-M-producing enterobacteria are endemic in Latin America and in some areas of North Eastern Europe. Data on their structure, properties and epidemiology are discussed. (C) 2000 Published by Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.
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- 2000
20. Comparison of Mycobacterium avium isolates from Greek AIDS and human immunodeficiency virus-negative patients by pulsed-field gel electrophoresis
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Kyriakopoulos, AM Matsiota-Bernard, P Marinis, E Legakis, NJ and Tassios, PT
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Objective To compare the chromosomal types of Mycobacterium avium strains infecting HIV-negative and AIDS patients in Greece. Methods In total, 41 Mycobacterium avium isolates, 23 from AIDS and 18 from HIV-negative patients, were compared by pulsed-field gel electrophoresis of genomic DNA after XbaI digestion. The majority (87%) of AIDS isolates were from disseminated infection, while the majority (61%) of HIV-negative isolates were from children with cervical lymphadenitis. Results Pulsed-field gel electrophoresis classified strains whose electrophoretic patterns were at least 85% similar into three clusters, A (four isolates), B (12 isolates), and C (15), while 10 isolates remained outside of these clusters. There was no statistically significant correlation of any PFGE cluster with a specific patient group. Within each patient group, no significant correlation of PFGE type with time, place of residence or, in the case of AIDS patients, hospital attended was observed. Conclusions Genotypic similarities between isolates responsible for disseminated infection in AIDS patients and lymphadenitis in HIV-negative children suggest that related strains, possibly from an environmental source, cause both types of infections.
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- 2000
21. Detrimental effect of the combination of R164S with G238S in TEM-1 beta-lactamase on the extended-spectrum activity conferred by each single mutation
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Giakkoupi, P Tzelepi, E Tassios, PT Legakis, NJ and Tzouvelekis, LS
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The non-naturally occurring TEM-1 beta-lactamase mutant R164S:G238S, as well as the R164S (TEM-12) and G238S (TEM-19) beta-lactamases, were constructed and expressed in Escherichia coli under isogenic conditions. Comparison of susceptibilities to beta-lactam antibiotics and substrate profiles showed that the combination of R164S with G238S drastically reduced the extended-spectrum activity of the respective single mutants.
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- 2000
22. Gradual increase in the minimum inhibitory concentration of penicillin among both susceptible and resistant Streptococcus pneumoniae isolates from Greek children during 1995-1997
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Fotopoulou, N Tsiplakou, S Maniatis, AN Pangali, A and Kouppari, G Legakis, NJ Tassios, PT
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A total of 140 non-replicate Streptococcus pneumoniae community isolates from Greek children collected during the period 1995-1997 were studied. Combined intermediate and high penicillin resistance rates were 23% in 1995, 29% in 1996, and 27% in 1997. The proportion of highly resistant isolates steadily increased from 2% in 1995 to 12% in 1997. There was no significant difference in penicillin resistance rates among colonizing and infecting isolates (23 and 27%, respectively). Over the study period, a clear shift towards higher penicillin MIC was observed among both the susceptible and resistant groups. Thus, penicillin resistance rates were equally high among colonizing and infecting isolates and resistance levels appeared to be gradually increasing throughout the entire S. pneumoniae population. (C) 1999 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.
- Published
- 1999
23. Spread of a Salmonella typhimurium clone resistant to expanded-spectrum cephalosporins in three European countries
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Tassios, PT Gazouli, M Tzelepi, E Milch, H Kozlova, N and Sidorenko, S Legakis, NJ Tzouvelekis, LS
- Abstract
Twelve Salmonella typhimurium strains resistant to broad-spectrum cephalosporins were isolated from cases of gastroenteritis during 1996 to 1998 in Russia, Hungary, and Greece. Resistance was due to the production of CTX-M-type extended-spectrum beta-lactamases encoded by similar 12-kb plasmids. By pulsed-field gel electrophoresis, all strains shared the same chromosomal type. These data suggest that an S. typhimurium clone resistant to broad-spectrum cephalosporins is present in at least three European countries.
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- 1999
24. A multi-centre study of nosocomial methicillin-resistant Staphylococcus aureus in Greece
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Kantzanou, M Tassios, PT Tseleni-Kotsovili, A Maniatis, AN and Vatopoulos, AC Legakis, NJ Greek MRSA Study Grp
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biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses - Abstract
All 105 non-replicate consecutive Staphylococcus aureus strains isolated in 1997 from seven Creek hospitals, were found to be susceptible to vancomycin, teicoplanin and chloramphenicol, but only five (8%) were susceptible to all 16 antibiotics tested. Forty-three (41%) isolates were methicillin-resistant, 58% homogeneously (homMRSA) and 42% heterogeneously (hetMRSA). Resistance of homMRSA strains to other antibiotics was generally high (88-100%), although only one strain was resistant to netilmicin. Resistance in hetMRSA (6-39%) or in MSSA (5-11%) was significantly lower Consequently, the majority (76%) of homMRSA were multi-drug resistant, while the dominant phenotype of hetMRSA and MSSA was resistance to penicillin (50% and 76%, respectively). Comparison of these strains with isolates from 1994 showed higher resistance rates to erythromycin among MSSA, to erythromycin and amikacin among hetMRSA and to rifampicin among homMRSA strains. (C) 1999 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.
- Published
- 1999
25. Molecular typing of methicillin-resistant Staphylococcus aureus by pulsed-field gel electrophoresis: Comparison of results obtained in a multilaboratory effort using identical protocols and MRSA strains
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Chung, M, de Lencastre, H, Matthews, P, Tomasz, A, Adamsson, I, Aires de Sousa, M, Camou, T, Cocuzza, C, Corso, A, Couto, I, Dominguez, A, Gniadkowski, M, Goering, R, Gomes, A, Kikuchi, K, Marchese, A, Mato, R, Melter, O, Oliveira, D, Palacio, R, Sá Leão, R, Santos Sanches, I, Song, J, Tassios, P, Villari, P, COCUZZA, CLEMENTINA ELVEZIA, Song, JH, Tassios, PT, Villari, P., Chung, M, de Lencastre, H, Matthews, P, Tomasz, A, Adamsson, I, Aires de Sousa, M, Camou, T, Cocuzza, C, Corso, A, Couto, I, Dominguez, A, Gniadkowski, M, Goering, R, Gomes, A, Kikuchi, K, Marchese, A, Mato, R, Melter, O, Oliveira, D, Palacio, R, Sá Leão, R, Santos Sanches, I, Song, J, Tassios, P, Villari, P, COCUZZA, CLEMENTINA ELVEZIA, Song, JH, Tassios, PT, and Villari, P.
- Abstract
Pulsed-field gel electrophoresis (PFGE) has become the gold standard of molecular methods in epidemiological investigations. In spite of its high resolving power, use of the method has been hampered by inadequate laboratory-to-laboratory reproducibility. In the project described here we have addressed this problem by organizing a multilaboratory effort in which the same bacterial strains (subtype variants of the Iberian and Brazilian methicillin-resistant Staphylococcus aureus--MRSA--clones) were analyzed by twenty investigators in thirteen different laboratories according to an indentical protocol, which is reproduced here in detail. PFGE patterns obtained were analyzed at a central laboratory in order to identify specific technical problems that produced substandard macrorestriction patterns. The results including the specific technical problems and their most likely causes are described in this communication. Also listed are seven major epidemic clones of MRSA which have been characterized by molecular fingerprinting techniques and the prototypes of which have been deposited at the American Type Culture Collection, from where they will be available for interested investigators for the purpose of typing MRSA isolates. It is hoped that this communication will contribute to the improvement of the reproducibility and technical/aesthetic quality of PFGE analysis.
- Published
- 2009
26. Emergence of multidrug resistance in ubiquitous and dominant Pseudomonas aeruginosa serogroup O : 11
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Tassios, PT Gennimata, V Maniatis, AN Fock, C Legakis, NJ Greek Pseudomonas Aeruginosa Study Grp
- Abstract
The serotypes of 88 nonreplicate nosocomial Pseudomonas aeruginosa isolates from 11 Greek hospitals were studied in relation to their antibiotic susceptibilities. Rates of resistance to beta-lactams, aminoglycosides, and quinolones ranged from 31 to 65%, except for those to ceftazidime (15%) and imipenem (21%). Four serotypes were dominant: O:12 (25% of isolates), O:1 (17%), O:11 (16%), and O:6 (10%), Multidrug resistance rates in the major serogroups O:12 (91%) and O:11 (79%) were higher than those in serogroups O:1 (40%) and O:6 (43%). Further typing with respect to pulsed-field gel electrophoresis patterns following XbaI digestion of genomic DNA discriminated the isolates into 74 types, Pulsed-field gel electrophoresis revealed that the ubiquitous O:12 group was genetically homogeneous, since 95% of strains belonged to two clusters of genotypic similarity, while the O:11 strains, present in 8 of the 11 hospitals, were distributed among five such clusters. Therefore, apart from the already reported O:12 multidrug-resistant European clone, an O:11 population, characterized by a serotype known to be dominant in the environment and the hospital in several parts of the world, but previously not associated,vith multidrug resistance to antibiotics, has progressed to a multidrug-resistant state.
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- 1998
27. Rapid discrimination of Mycobacterium avium strains from AIDS patients by randomly amplified polymorphic DNA analysis
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MatsiotaBernard, P Waser, S Tassios, PT Kyriakopoulos, A and Legakis, NJ
- Subjects
bacterial infections and mycoses - Abstract
A randomly amplified polymorphic DNA (RAPD) analysis was performed for the molecular typing of Mycobacterium avium strains. This method was applied to epidemiologically unrelated M. avium strains isolated from the blood of 10 different AIDS patients and to strains that were considered epidemiologically related, as they had been isolated from the same patient but from different body locations (4 patients, 10 strains). Three oligonucleotide primers among the six tested were found to generate RAPD profiles with DNA from all M. avium strains and to successfully type them. This method for the typing of M. avium strains is rapid and easy to perform.
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- 1997
28. Molecular epidemiology of antibiotic resistance of Salmonella enteritidis during a 7-year period in Greece
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Tassios, PT Markogiannakis, A Vatopoulos, AC KAtsanikou, E and Velonakis, EN KoureaKremastinou, J Legakis, NJ
- Abstract
A significant increase in the frequency of isolation of Salmonella enteritidis has been observed during recent years in Greece, parallelled by an increasing rate of resistance of this organism to antibiotics, A substantial proportion of ampicillin- and doxycycline-resistant isolates exhibited cross-resistance to drugs of other classes, such as sulfonamides and streptomycin. Isolates of human origin were overall less resistant than those of animal or food-feed origin, Indeed, strains associated with animal infections were characterized by the highest rates of resistance to several antibiotics, These phenotypic data were correlated with genotypic information concerning two distinct populations: isolates from all sources that were resistant only to ampicillin, the drug toward which resistance rates were highest, and a control group of sensitive isolates, Ampicillin resistance was due to a 34-MDa conjugative plasmid, DNA fingerprinting by macrorestriction of genomic DNA revealed two types, A and B, common to both ampicillin-resistant and -sensitive strains, with 80 to 90% of strains being of type A, However, a third type, C, was specific for the sensitive population, representing 17% of those strains, Therefore, although the majority of resistant isolates were genetically related to sensitive ones, there existed a susceptible clone which had not acquired any resistance traits.
- Published
- 1997
29. Distinct genotypic clusters of heterogeneously and homogeneously methicillin-resistant Staphylococcus aureus from a Greek hospital
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Tassios, PT Vatopoulos, AC Xanthaki, A Mainas, E and Goering, RV Legakis, NJ
- Subjects
biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses - Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) strains isolated over a one-year period from a Greek hospital were tested for their levels of resistance to methicillin by population analysis. Heterogeneously resistant strains belonged to classes I, II, and II/III, whereas homogeneously resistant ones belonged to class IV. Strains of all classes possessed the mecA gene. Pulsed-field gel electrophoresis (PFGE) of Smal-digested genomic DNA revealed that all heterogeneously resistant strains were related. Homogeneously resistant strains were also closely related, but in a cluster distinct from the heterogeneous one. The methicillin-sensitive strains displayed a greater variety of PFGE types compared to MRSA isolates.
- Published
- 1997
30. Characterization to species level of Mycobacterium avium complex strains from human immunodeficiency virus-positive and -negative patients
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Kyriakopoulos, AM Tassios, PT MatsiotaBernard, P Marinis, E and Tsaousidou, S Legakis, NJ
- Abstract
Forty human clinical Mycobacterium avium-M. intracellulare complex strains isolated in Greece were characterized to the species level by PCR with three sets of primers specific for one or both species. M. avium predominated in both human immunodeficiency virus-positive and -negative patients, but the frequency of M. intracellulare isolation appeared to be higher in the latter.
- Published
- 1997
31. In vivo deletion of the methicillin resistance mec region from the chromosome of Staphylococcus aureus strains
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UCL, Deplano, A., Glupczynski, Gerald, Tassios, PT, Godfroid, E., Struelens, MJ., UCL, Deplano, A., Glupczynski, Gerald, Tassios, PT, Godfroid, E., and Struelens, MJ.
- Abstract
Two sets of Staphylococcus aureus isolates recovered from two patients exhibited similar susceptibility profiles except for oxacillin susceptibility (MSSA) or resistance (MRSA). SmaI macrorestriction and inter-IS256 PCR analysis showed patterns closely related to the Belgian epidemic MRSA clone 1 in each pair of MSSA/MRSA strains. Loss of one large SmaI DNA fragment and concurrent gain of a smaller fragment in the MSSA isolates was observed. The mecA sequence present in the MRSA was absent in the MSSA variant. Therefore, in vivo deletion of the mec region may occur in some lineages of S. aureus more frequently than previously thought.
- Published
- 2000
32. Reduced susceptibility to vancomycin of nosocomial isolates of methicillin-resistant Staphylococcus aureus.
- Author
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Kantzanou, M, Tassios, PT, Tseleni-Kotsovili, A, Legakis, NJ, Vatopoulos, AC, Tassios, P T, Legakis, N J, and Vatopoulos, A C
- Abstract
The MICs of vancomycin for 56 random nosocomial Staphylococcus aureus isolates homogeneously resistant to methicillin (homMRSA), 16 heterogeneously resistant isolates (hetMRSA) and 25 susceptible isolates (MSSA) were determined by a standard broth microdilution method. Representative isolates were also tested by an agar incorporation method, the Etest and population analysis. Although always in the susceptible range, MICs of vancomycin for homMRSA were significantly higher than those for hetMRSA or MSSA. Moreover, a homMRSA strain belonging to one of the major Greek MRSA clones contained a sub-population of cells that could grow in the presence of vancomycin 8 mg/L at a frequency of 6.7 x 10(-8). [ABSTRACT FROM AUTHOR]
- Published
- 1999
- Full Text
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33. Enhanced and earlier detection of bacteremia and fungemia by multiplex polymerase chain reaction: how much enhanced, how much earlier, and at what cost?
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Falagas ME and Tassios PT
- Published
- 2008
- Full Text
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34. Prediction models in CMI.
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Leibovici L, Rodríguez-Baño J, Chemaly RF, Cutler S, Huttner A, Kalil AC, Leeflang M, Lina G, Paul M, Scudeller L, Tassios PT, and Yusuf E
- Published
- 2022
- Full Text
- View/download PDF
35. Bacterial next generation sequencing (NGS) made easy.
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Tassios PT and Moran-Gilad J
- Subjects
- Bacterial Infections diagnosis, Bacterial Infections drug therapy, Bacterial Infections microbiology, Computational Biology methods, Genome, Bacterial, Genomics methods, Humans, Whole Genome Sequencing, Bacteria genetics, High-Throughput Nucleotide Sequencing
- Published
- 2018
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36. Difficile indeed.
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Tassios PT
- Subjects
- Humans, Population Surveillance, Clostridioides difficile, Clostridium Infections
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- 2016
- Full Text
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37. Parasitic infections: their position and impact in the postindustrial world.
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Piperaki ET and Tassios PT
- Subjects
- Humans, Communicable Disease Control methods, Global Health, Parasitic Diseases epidemiology, Parasitic Diseases prevention & control
- Published
- 2016
- Full Text
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38. Differences in the epidemiology between paediatric and adult invasive Streptococcus pyogenes infections.
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Zachariadou L, Stathi A, Tassios PT, Pangalis A, Legakis NJ, and Papaparaskevas J
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Antigens, Bacterial, Bacterial Outer Membrane Proteins, Carrier Proteins, Child, Child, Preschool, Drug Resistance, Multiple, Bacterial, Female, Greece epidemiology, Humans, Infant, Male, Middle Aged, Prospective Studies, Risk Factors, Streptococcal Infections drug therapy, Streptococcus pyogenes drug effects, Surveys and Questionnaires, Streptococcal Infections epidemiology, Streptococcus pyogenes isolation & purification
- Abstract
In order to investigate for possible differences between paediatric and adult invasive Streptococcus pyogenes (iGAS) infections, a total of 142 cases were identified in 17 Greek hospitals during 2003-2007, of which 96 were children and 46 adults. Bacteraemia, soft tissue infections, streptococcal toxic shock syndrome (STSS), and necrotizing fasciitis were the main clinical presentations (67·6%, 45·1%, 13·4%, and 12·0% of cases, respectively). Bacteraemia and lymphadenitis were significantly more frequent in children (P=0·019 and 0·021, respectively), whereas STSS was more frequent in adults (P=0·017). The main predisposing factors in children were varicella and streptococcal pharyngotonsillitis (25% and 19·8%, respectively), as opposed to malignancy, intravenous drug abuse and diabetes mellitus in adults (19·6%, 15·2% and 10·9%, respectively). Of the two dominant emm-types, 1 and 12 (28·2% and 8·5%, respectively), the proportion of emm-type 12 remained stable during the study period, whereas emm-type 1 rates fluctuated considerably. Strains of emm-type 1 from children were associated with erythromycin susceptibility, STSS and intensive-care-unit admission, whereas emm-type 12 isolates from adults were associated with erythromycin and clindamycin resistance. Finally, specific emm-types were detected exclusively in adults or in children. In conclusion, several clinical and epidemiological differences were detected, that could prove useful in designing age-focused strategies for prevention and treatment of iGAS infections.
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- 2014
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39. Guidelines in infectious diseases: how reliable are they?
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Paul M, Roilides E, and Tassios PT
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- Evidence-Based Medicine, Humans, Communicable Disease Control, Communicable Diseases therapy, Practice Guidelines as Topic
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- 2013
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40. Carbapenemases in Klebsiella pneumoniae and other Enterobacteriaceae: an evolving crisis of global dimensions.
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Tzouvelekis LS, Markogiannakis A, Psichogiou M, Tassios PT, and Daikos GL
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Communicable Diseases, Emerging drug therapy, Communicable Diseases, Emerging microbiology, Enterobacteriaceae Infections drug therapy, Global Health, Humans, Mice, beta-Lactam Resistance, Bacterial Proteins metabolism, Enterobacteriaceae enzymology, Enterobacteriaceae Infections microbiology, Klebsiella pneumoniae enzymology, beta-Lactamases metabolism
- Abstract
Summary: The spread of Enterobacteriaceae, primarily Klebsiella pneumoniae, producing KPC, VIM, IMP, and NDM carbapenemases, is causing an unprecedented public health crisis. Carbapenemase-producing enterobacteria (CPE) infect mainly hospitalized patients but also have been spreading in long-term care facilities. Given their multidrug resistance, therapeutic options are limited and, as discussed here, should be reevaluated and optimized. Based on susceptibility data, colistin and tigecycline are commonly used to treat CPE infections. Nevertheless, a review of the literature revealed high failure rates in cases of monotherapy with these drugs, whilst monotherapy with either a carbapenem or an aminoglycoside appeared to be more effective. Combination therapies not including carbapenems were comparable to aminoglycoside and carbapenem monotherapies. Higher success rates have been achieved with carbapenem-containing combinations. Pharmacodynamic simulations and experimental infections indicate that modification of the current patterns of carbapenem use against CPE warrants further attention. Epidemiological data, though fragmentary in many countries, indicate CPE foci and transmission routes, to some extent, whilst also underlining the lack of international collaborative systems that could react promptly and effectively. Fortunately, there are sound studies showing successful containment of CPE by bundles of measures, among which the most important are active surveillance cultures, separation of carriers, and assignment of dedicated nursing staff.
- Published
- 2012
- Full Text
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41. Does it ever make sense to treat a bacterial infection with a drug against which the responsible pathogen possesses a resistance mechanism?
- Author
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Tassios PT and Miriagou V
- Subjects
- Animals, Humans, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents therapeutic use, Antitubercular Agents pharmacology, Bacterial Proteins biosynthesis, Carbapenems therapeutic use, Drug Resistance, Bacterial, Klebsiella Infections drug therapy, Klebsiella pneumoniae drug effects, Methicillin-Resistant Staphylococcus aureus drug effects, Mycobacterium tuberculosis drug effects, Staphylococcal Infections drug therapy, Staphylococcus aureus drug effects, beta-Lactamases biosynthesis
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- 2011
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42. Evolution and spread of a multidrug-resistant Proteus mirabilis clone with chromosomal AmpC-type cephalosporinases in Europe.
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D'Andrea MM, Literacka E, Zioga A, Giani T, Baraniak A, Fiett J, Sadowy E, Tassios PT, Rossolini GM, Gniadkowski M, and Miriagou V
- Subjects
- Chromosomes, Bacterial, Humans, Microbial Sensitivity Tests, Proteus mirabilis enzymology, Bacterial Proteins genetics, Drug Resistance, Multiple, Bacterial, Evolution, Molecular, Proteus mirabilis drug effects, Proteus mirabilis genetics, beta-Lactamases genetics
- Abstract
Proteus mirabilis isolates obtained in 1999 to 2008 from three European countries were analyzed; all carried chromosomal AmpC-type cephalosporinase bla(CMY) genes from a Citrobacter freundii origin (bla(CMY-2)-like genes). Isolates from Poland harbored several bla(CMY) genes (bla(CMY-4), bla(CMY-12), bla(CMY-14), bla(CMY-15), and bla(CMY-38) and the new gene bla(CMY-45)), while isolates from Italy and Greece harbored bla(CMY-16) only. Earlier isolates with bla(CMY-4) or bla(CMY-12), recovered in France from Greek and Algerian patients, were also studied. All isolates showed striking similarities. Their bla(CMY) genes resided within ISEcp1 transposition modules, named Tn6093, characterized by a 110-bp distance between ISEcp1 and bla(CMY), and identical fragments of both C. freundii DNA and a ColE1-type plasmid backbone. Moreover, these modules were inserted into the same chromosomal site, within the pepQ gene. Since ColE1 plasmids carrying ISEcp1 with similar C. freundii DNA fragments (Tn6114) had been identified earlier, it is likely that a similar molecule had mediated at some stage this DNA transfer between C. freundii and P. mirabilis. In addition, isolates with bla(CMY-12), bla(CMY-15), and bla(CMY-38) genes harbored a second bla(CMY) copy within a shorter ISEcp1 module (Tn6113), always inserted downstream of the ppiD gene. Sequence analysis of all mobile bla(CMY-2)-like genes indicated that those integrated in the P. mirabilis chromosome form a distinct cluster that may have evolved by the stepwise accumulation of mutations. All of these observations, coupled to strain typing data, suggest that the bla(CMY) genes studied here may have originated from a single ISEcp1-mediated mobilization-transfer-integration process, followed by the spread and evolution of a P. mirabilis clone over time and a large geographic area.
- Published
- 2011
- Full Text
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43. Two successfully treated cases of Staphylococcus lugdunensis endocarditis.
- Author
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Chatzigeorgiou KS, Ikonomopoulou C, Kalogeropoulou S, Siafakas N, Giannopoulos G, Antoniadou A, Tassios PT, Tarpatzi E, Giannitsioti E, Vlachakos D, Ikonomopoulos T, Petinaki E, and Zerva L
- Subjects
- Aged, 80 and over, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents therapeutic use, Aortic Valve microbiology, Endocarditis, Bacterial microbiology, Female, Heart Valve Prosthesis microbiology, Humans, Microbial Sensitivity Tests, Middle Aged, Pacemaker, Artificial microbiology, Prognosis, Staphylococcal Infections microbiology, Staphylococcus lugdunensis isolation & purification, Treatment Outcome, Endocarditis, Bacterial drug therapy, Endocarditis, Bacterial surgery, Staphylococcal Infections drug therapy, Staphylococcal Infections surgery, Staphylococcus lugdunensis drug effects
- Abstract
Prosthetic valve and pacemaker lead endocarditis by Staphylococcus lugdunensis remain very rare, while the former is associated with an ominous prognosis. Two cases involving a prosthetic aortic valve and a pacemaker lead, respectively, are reported. Despite disease severity and delayed diagnosis, patients recovered fully with combined antimicrobial and surgical treatment., (Copyright © 2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
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44. Risk factors for bloodstream infection with Klebsiella pneumoniae producing VIM-1 metallo-beta-lactamase.
- Author
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Daikos GL, Vryonis E, Psichogiou M, Tzouvelekis LS, Liatis S, Petrikkos P, Kosmidis C, Tassios PT, Bamias G, and Skoutelis A
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Bacteremia epidemiology, Bacteremia microbiology, Female, Hospitals, Humans, Male, Middle Aged, Risk Factors, Young Adult, beta-Lactamases biosynthesis, Klebsiella Infections epidemiology, Klebsiella Infections microbiology, Klebsiella pneumoniae isolation & purification
- Abstract
Objectives: To identify risk factors for bloodstream infections (BSIs) caused by VIM-1-producing Klebsiella pneumoniae (VPKP)., Methods: Consecutive patients with K. pneumoniae BSIs were identified in three tertiary care hospitals between February 2004 and March 2006. Patients infected with VPKP were designated as cases and those infected with non-VPKP as controls. Potential risk factors for VPKP BSIs were examined by univariate and multivariate analysis., Results: A total of 178 patients with K. pneumoniae BSIs were identified; 67 (37.6%) were infected with VPKP (cases) and 111 with non-VPKP (controls). In multivariate analysis, cases were more likely to have been in an intensive care unit (ICU) [odds ratio (OR), 6.78; 95% confidence interval (CI), 2.69-17.06; P < 0.001], have had prior exposure to >3 different classes of antibiotics (OR, 12.6; 95% CI, 2.17-73.27; P = 0.01) and have had prior use of carbapenems (OR, 2.83; 95% CI, 1.07-7.49; P = 0.03)., Conclusions: Stay in an ICU, prior use of carbapenems and prior exposure to >3 different classes of antibiotics were independent predictors for VPKP BSIs. These findings provide guidance for antibiotic policies and infection control strategies to contain the spread of VPKP.
- Published
- 2010
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45. Hard to swallow--emerging and re-emerging issues in foodborne infection.
- Author
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Tassios PT and Kerr KG
- Subjects
- Humans, Food Technology, Foodborne Diseases
- Published
- 2010
- Full Text
- View/download PDF
46. Prevalence and characterization of class 1 integrons in Escherichia coli of poultry and human origin.
- Author
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Vasilakopoulou A, Psichogiou M, Tzouvelekis L, Tassios PT, Kosmidis C, Petrikkos G, Roma ES, Charvalos E, Passiotou M, Avlami A, and Daikos GL
- Subjects
- Animals, Blood microbiology, DNA, Bacterial chemistry, Disk Diffusion Antimicrobial Tests, Drug Resistance, Multiple, Bacterial, Escherichia coli classification, Escherichia coli isolation & purification, Foodborne Diseases prevention & control, Gastrointestinal Tract microbiology, Greece, Humans, Inpatients statistics & numerical data, Outpatients statistics & numerical data, Phenotype, Polymerase Chain Reaction, Sputum microbiology, Suppuration microbiology, Urine microbiology, Drug Resistance, Microbial genetics, Escherichia coli genetics, Integrons genetics, Poultry microbiology
- Abstract
A prospective study was conducted to determine the prevalence and the gene-cassette content of class 1 integrons in Escherichia coli of poultry and human origin. A total of 235 E. coli isolates were examined; 65 were derived from farm poultry, 80 from hospitalized, and 90 from nonhospitalized patients. Susceptibilities to a range of antimicrobial agents were determined by disk diffusion. Int1-specific polymerase chain reaction, conserved-segment polymerase chain reaction, and DNA sequencing were used to determine the presence, length, and content of integrons. The relatedness among the isolates was examined by pulsed-field gel electrophoresis of XbaI digests of genomic DNA. The integron carriage rate for poultry isolates was 49.2%, whereas the carriage rate for hospital isolates was 26.2% and for community 11.1%. Multidrug resistance (resistance to three or more classes of antibiotics) phenotypes were observed in 96.8% of the integron-positive isolates, whereas only 34.9% of nonintegron-carrying organisms were multidrug resistant (p < 0.001). Seven integron types ranging in size from 663 to 2674 bp were identified; six types were observed in poultry isolates, five in hospital, and three in community isolates. Each integron type carried a distinct gene-cassette combination. The most prevalent gene cassettes belonged to the aad and dfr families. Identical integrons were detected in E. coli of human and poultry origin. A large reservoir of integrons exists in E. coli of poultry origin. The horizontal transfer of class 1 integrons among bacteria of poultry and human origins may contribute in the dissemination of antimicrobial resistance.
- Published
- 2009
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- View/download PDF
47. Prospective observational study of the impact of VIM-1 metallo-beta-lactamase on the outcome of patients with Klebsiella pneumoniae bloodstream infections.
- Author
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Daikos GL, Petrikkos P, Psichogiou M, Kosmidis C, Vryonis E, Skoutelis A, Georgousi K, Tzouvelekis LS, Tassios PT, Bamia C, and Petrikkos G
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Female, Greece epidemiology, Humans, Klebsiella pneumoniae genetics, Klebsiella pneumoniae isolation & purification, Male, Microbial Sensitivity Tests, Middle Aged, Prospective Studies, Young Adult, beta-Lactamases genetics, beta-Lactamases metabolism, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents therapeutic use, Bacteremia drug therapy, Bacteremia microbiology, Bacteremia mortality, Carbapenems pharmacology, Carbapenems therapeutic use, Klebsiella Infections drug therapy, Klebsiella Infections microbiology, Klebsiella Infections mortality, Klebsiella pneumoniae drug effects, Klebsiella pneumoniae enzymology, beta-Lactam Resistance
- Abstract
VIM-1-producing Klebsiella pneumoniae (VPKP) is an emerging pathogen. A prospective observational study was conducted to evaluate the importance of VIM production on outcome of patients with K. pneumoniae bloodstream infections (BSIs). Consecutive patients with K. pneumoniae BSIs were identified and followed up until patient discharge or death. A total of 162 patients were included in the analysis; 67 (41.4%) were infected with VPKP, and 95 were infected with non-VPKP. Fourteen of the patients infected with VPKP were carbapenem resistant (Carb(r)) (MIC > 4 mug/ml), whereas none of the non-VPKP exhibited carbapenem resistance. The patients infected with a Carb(r) organism were more likely (odds ratio, 4.08; 95% confidence interval [CI], 1.29 to 12.85; P = 0.02) to receive inappropriate empirical therapy. The all-cause 14-day mortality rates were 15.8% (15 of 95) for patients infected with VIM-negative organisms, 18.9% (10 of 53) for those infected with VIM-positive carbapenem-susceptible organisms, and 42.9% (6 of 14) for those infected with VIM-positive Carb(r) organisms (P = 0.044). In Cox regression analysis, age (hazard ratio [HR], 1.03; 95% CI, 1.01 to 1.06; P = 0.021), rapidly fatal underlying disease (HR, 2.84; 95% CI, 1.26 to 6.39; P = 0.012), and carbapenem resistance (HR, 2.83; 95% CI, 1.08 to 7.41; P = 0.035) were independent predictors of death. After adjustment for inappropriate empirical or definitive therapy, the effect of carbapenem resistance on outcome was reduced to a level of nonsignificance. In patients with K. pneumoniae BSIs, carbapenem resistance, advanced, age, and severity of underlying disease were independent predictors of outcome, whereas VIM production had no effect on mortality. The higher mortality associated with carbapenem resistance was probably mediated by the failure to provide effective therapy.
- Published
- 2009
- Full Text
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48. Clinical and microbiological characteristics of severe Streptococcus pyogenes disease in Europe.
- Author
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Luca-Harari B, Darenberg J, Neal S, Siljander T, Strakova L, Tanna A, Creti R, Ekelund K, Koliou M, Tassios PT, van der Linden M, Straut M, Vuopio-Varkila J, Bouvet A, Efstratiou A, Schalén C, Henriques-Normark B, and Jasir A
- Subjects
- Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Antigens, Bacterial genetics, Bacterial Outer Membrane Proteins genetics, Bacterial Typing Techniques, Carrier Proteins genetics, Child, Child, Preschool, Europe epidemiology, Fasciitis, Necrotizing microbiology, Female, Humans, Infant, Infant, Newborn, Male, Middle Aged, Prospective Studies, Shock, Septic microbiology, Superantigens genetics, Young Adult, Streptococcal Infections epidemiology, Streptococcal Infections microbiology, Streptococcus pyogenes classification, Streptococcus pyogenes isolation & purification
- Abstract
In an attempt to compare the epidemiology of severe Streptococcus pyogenes infection within Europe, prospective data were collected through the Strep-EURO program. Surveillance for severe cases of S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in 11 countries across Europe by using a standardized case definition and questionnaire. Patient data as well as bacterial isolates were collected and characterized by T and M/emm typing, and selected strains were analyzed for the presence of superantigen genes. Data were analyzed to compare the clinical and microbiological patterns of the infections across the participating countries. A total of 4,353 isolates were collected from 5,521 cases with severe S. pyogenes infections who were identified. A wide diversity of M/emm types (n = 104) was found among the S. pyogenes clinical isolates, but the M/emm type distribution varied broadly between participating countries. The 10 most predominant M/emm types were M/emm type 1 (M/emm1), M/emm28, M/emm3, M/emm89, M/emm87, M/emm12, M/emm4, M/emm83, M/emm81, and M/emm5, in descending order. A correlation was found between some specific disease manifestations, the age of the patients, and the emm types. Although streptococcal toxic shock syndrome and necrotizing fasciitis were caused by a large number of types, they were particularly associated with M/emm1 and M/emm3. The emm types included in the 26-valent vaccine under development were generally well represented in the present material; 16 of the vaccine types accounted for 69% of isolates. The Strep-EURO collaborative program has contributed to enhancement of the knowledge of the spread of invasive disease caused by S. pyogenes within Europe and encourages future surveillance by the notification of cases and the characterization of strains, which are important for vaccination strategies and other health care issues.
- Published
- 2009
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49. Prevalence of emm types 1 and 12 from invasive Streptococcus pyogenes disease in Greece--results of enhanced surveillance.
- Author
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Stathi A, Papaparaskevas J, Zachariadou L, Pangalis A, Legakis NJ, Tseleni-Kotsovili A, and Tassios PT
- Subjects
- Anti-Bacterial Agents pharmacology, Antigens, Bacterial metabolism, Bacterial Outer Membrane Proteins metabolism, Carrier Proteins metabolism, Electrophoresis, Gel, Pulsed-Field, Erythromycin pharmacology, Greece epidemiology, Humans, Microbial Sensitivity Tests, Prevalence, Streptococcal Infections microbiology, Streptococcus pyogenes classification, Streptococcus pyogenes genetics, Tetracycline Resistance, Antigens, Bacterial classification, Antigens, Bacterial genetics, Bacterial Outer Membrane Proteins classification, Bacterial Outer Membrane Proteins genetics, Carrier Proteins classification, Carrier Proteins genetics, Drug Resistance, Bacterial, Population Surveillance methods, Streptococcal Infections epidemiology, Streptococcus pyogenes drug effects
- Abstract
Among a total of 101 isolates from the first systematic multicentre surveillance effort concerning invasive Streptococcus pyogenes disease in Greece, conducted between 2003 and 2005 and covering 38% of the population, emm types 1 and 12 were prevalent, being responsible for 27 and nine cases, respectively. The isolates from the remaining 65 cases were assigned to 26 other emm types. Erythromycin resistance (12 isolates) was primarily mef(A)-mediated, although all emm type 1 strains were susceptible. Tetracycline resistance, due mostly to tet(M), was detected in 26 isolates. Subtyping by pulsed-field gel electrophoresis yielded 50 chromosomal fingerprints, thus discriminating further among ten of the 28 observed emm types.
- Published
- 2008
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50. Ongoing epidemic of blaVIM-1-positive Klebsiella pneumoniae in Athens, Greece: a prospective survey.
- Author
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Psichogiou M, Tassios PT, Avlamis A, Stefanou I, Kosmidis C, Platsouka E, Paniara O, Xanthaki A, Toutouza M, Daikos GL, and Tzouvelekis LS
- Subjects
- Anti-Bacterial Agents pharmacology, Carbapenems pharmacology, Cross Infection enzymology, Cross Infection microbiology, Drug Resistance, Multiple, Bacterial genetics, Greece epidemiology, Humans, Klebsiella Infections drug therapy, Klebsiella Infections microbiology, Klebsiella pneumoniae drug effects, Klebsiella pneumoniae enzymology, Microbial Sensitivity Tests, Prospective Studies, beta-Lactamases biosynthesis, beta-Lactamases genetics, Anti-Bacterial Agents therapeutic use, Carbapenems therapeutic use, Cross Infection epidemiology, Disease Outbreaks, Klebsiella Infections epidemiology, Klebsiella pneumoniae isolation & purification
- Abstract
Objectives: To determine the current frequency and study the characteristics of VIM-1-producing Klebsiella pneumoniae isolates from bloodstream infections in Greek hospitals., Methods: All blood isolates of K. pneumoniae were prospectively collected during 2004-06 in three teaching hospitals located in Athens. MICs of antibiotics were determined by the Etest. Extended-spectrum- (ESBL) and metallo-beta-lactamase (MBL) production was examined by clavulanate- and EDTA-based techniques, respectively. Isolates were typed by PFGE of XbaI-digested genomic DNA. Detection of bla(VIM-1) and mapping of the VIM-1-encoding integrons were performed by PCR and sequencing. Beta-lactamase activities were analysed by IEF and imipenem hydrolysis was assessed by spectrophotometry. VIM-1-encoding plasmids were transferred to Escherichia coli by conjugation and transformation and characterized by Inc/rep typing and RFLP., Results: Sixty-seven (37.6%) of 178 K. pneumoniae blood isolates were bla(VIM-1)-positive (VPKP); 77.8% of these were from ICUs. All VPKP isolates were multidrug-resistant. The MICs of carbapenems for VPKP varied from the susceptible range to high-level resistance overlapping with those of MBL-negative isolates. The EDTA-imipenem synergy methods had reduced sensitivity in detecting VPKP isolates when the MICs were in the susceptible range. ESBL production was common among VPKP isolates (n = 45, 67.2%) as indicated by resistance to aztreonam and confirmed by a clavulanate-based double-disc synergy test. The responsible ESBL was always an SHV-5-type enzyme as indicated by IEF. PFGE identified eight clusters (A-H) of VPKP isolates with related (>80%) patterns, as well as four unique types. Both inter-hospital spread of several clones and genotypic similarities among susceptible, ESBL-positive and VPKP isolates were also observed. Location of bla(VIM-1) and expression of VIM-1 were studied in 12 isolates representing the eight PFGE clusters. In all isolates, bla(VIM-1) was part of a class 1 integron that also carried aacA4, dhfrI, aadA and sulI. In eight isolates (clusters C, D, G and H), the bla(VIM-1) integron was located in transferable IncN plasmids. A cluster F isolate carried a VIM-1-encoding, self-transferable plasmid that was not typeable by Inc/rep typing. VIM-1-encodingreplicons were not identified in three isolates (PFGE clusters A, B and E). VPKP isolates exhibited differences in imipenem-hydrolysing activities which, however, were not correlated with the respective carbapenem MICs., Conclusions: A multiclonal epidemic of bla(VIM-1)-carrying K. pneumoniae is under way in the majorhospitals in Greece. Microorganisms producing both VIM-1 and SHV-5 constitute the prevalent multidrug-resistant population of K. pneumoniae in this setting.
- Published
- 2008
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