<it>In vitro </it>activity of tigecycline in combination with various antimicrobials against multidrug resistant <it>Acinetobacter baumannii</it>
<p>Abstract</p> <p>Background</p> <p>Infections sustained by multidrug-resistant (MDR) and pan-resistant <it>Acinetobacter baumannii </it>have become a challenging problem in Intensive Care Units. Tigecycline provided new hope for the treatment of MDR <it...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2009-05-01
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| Series: | Annals of Clinical Microbiology and Antimicrobials |
| Online Access: | http://www.ann-clinmicrob.com/content/8/1/18 |
| _version_ | 1818806211071442944 |
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| author | Petrosillo Nicola Capone Alessandro D'Arezzo Silvia Principe Luigi Visca Paolo |
| author_facet | Petrosillo Nicola Capone Alessandro D'Arezzo Silvia Principe Luigi Visca Paolo |
| author_sort | Petrosillo Nicola |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Infections sustained by multidrug-resistant (MDR) and pan-resistant <it>Acinetobacter baumannii </it>have become a challenging problem in Intensive Care Units. Tigecycline provided new hope for the treatment of MDR <it>A. baumannii </it>infections, but isolates showing reduced susceptibility have emerged in many countries, further limiting the therapeutic options. Empirical combination therapy has become a common practice to treat patients infected with MDR <it>A. baumannii</it>, in spite of the limited microbiological and clinical evidence supporting its efficacy. Here, the <it>in vitro </it>interaction of tigecycline with seven commonly used anti-<it>Acinetobacter </it>drugs has been assessed.</p> <p>Methods</p> <p>Twenty-two MDR <it>A. baumannii </it>isolates from Intensive Care Unit (ICU) patients and two reference strains for the European clonal lineages I and II (including 3, 15 and 6 isolates that were resistant, intermediate and susceptible to tigecycline, respectively) were tested. Antimicrobial agents were: tigecycline, levofloxacin, piperacillin-tazobactam, amikacin, imipenem, rifampicin, ampicillin-sulbactam, and colistin. MICs were determined by the broth microdilution method. Antibiotic interactions were determined by chequerboard and time-kill assays. Only antibiotic combinations showing synergism or antagonism in both chequerboard and time-kill assays were accepted as authentic synergistic or antagonistic interactions, respectively.</p> <p>Results</p> <p>Considering all antimicrobials in combination with tigecycline, chequerboard analysis showed 5.9% synergy, 85.7% indifference, and 8.3% antagonism. Tigecycline showed synergism with levofloxacin (4 strains; 16.6%), amikacin (2 strains; 8.3%), imipenem (2 strains; 8.3%) and colistin (2 strains; 8.3%). Antagonism was observed for the tigecycline/piperacillin-tazobactam combination (8 strains; 33.3%). Synergism was detected only among tigecycline non-susceptible strains. Time-kill assays confirmed the synergistic interaction between tigecycline and levofloxacin, amikacin, imipenem and colistin for 5 of 7 selected isolates. No antagonism was confirmed by time-kill assays.</p> <p>Conclusion</p> <p>This study demonstrates the <it>in vitro </it>synergistic activity of tigecycline in combination with colistin, levofloxacin, amikacin and imipenem against five tigecycline non-susceptible <it>A. baumannii </it>strains, opening the way to a more rationale clinical assessment of novel combination therapies to combat infections caused by MDR and pan-resistant <it>A. baumannii</it>.</p> |
| first_indexed | 2024-12-18T19:06:09Z |
| format | Article |
| id | doaj.art-ada3d4016fd74440a43d28589eabeb27 |
| institution | Directory Open Access Journal |
| issn | 1476-0711 |
| language | English |
| last_indexed | 2024-12-18T19:06:09Z |
| publishDate | 2009-05-01 |
| publisher | BMC |
| record_format | Article |
| series | Annals of Clinical Microbiology and Antimicrobials |
| spelling | doaj.art-ada3d4016fd74440a43d28589eabeb272022-12-21T20:56:25ZengBMCAnnals of Clinical Microbiology and Antimicrobials1476-07112009-05-01811810.1186/1476-0711-8-18<it>In vitro </it>activity of tigecycline in combination with various antimicrobials against multidrug resistant <it>Acinetobacter baumannii</it>Petrosillo NicolaCapone AlessandroD'Arezzo SilviaPrincipe LuigiVisca Paolo<p>Abstract</p> <p>Background</p> <p>Infections sustained by multidrug-resistant (MDR) and pan-resistant <it>Acinetobacter baumannii </it>have become a challenging problem in Intensive Care Units. Tigecycline provided new hope for the treatment of MDR <it>A. baumannii </it>infections, but isolates showing reduced susceptibility have emerged in many countries, further limiting the therapeutic options. Empirical combination therapy has become a common practice to treat patients infected with MDR <it>A. baumannii</it>, in spite of the limited microbiological and clinical evidence supporting its efficacy. Here, the <it>in vitro </it>interaction of tigecycline with seven commonly used anti-<it>Acinetobacter </it>drugs has been assessed.</p> <p>Methods</p> <p>Twenty-two MDR <it>A. baumannii </it>isolates from Intensive Care Unit (ICU) patients and two reference strains for the European clonal lineages I and II (including 3, 15 and 6 isolates that were resistant, intermediate and susceptible to tigecycline, respectively) were tested. Antimicrobial agents were: tigecycline, levofloxacin, piperacillin-tazobactam, amikacin, imipenem, rifampicin, ampicillin-sulbactam, and colistin. MICs were determined by the broth microdilution method. Antibiotic interactions were determined by chequerboard and time-kill assays. Only antibiotic combinations showing synergism or antagonism in both chequerboard and time-kill assays were accepted as authentic synergistic or antagonistic interactions, respectively.</p> <p>Results</p> <p>Considering all antimicrobials in combination with tigecycline, chequerboard analysis showed 5.9% synergy, 85.7% indifference, and 8.3% antagonism. Tigecycline showed synergism with levofloxacin (4 strains; 16.6%), amikacin (2 strains; 8.3%), imipenem (2 strains; 8.3%) and colistin (2 strains; 8.3%). Antagonism was observed for the tigecycline/piperacillin-tazobactam combination (8 strains; 33.3%). Synergism was detected only among tigecycline non-susceptible strains. Time-kill assays confirmed the synergistic interaction between tigecycline and levofloxacin, amikacin, imipenem and colistin for 5 of 7 selected isolates. No antagonism was confirmed by time-kill assays.</p> <p>Conclusion</p> <p>This study demonstrates the <it>in vitro </it>synergistic activity of tigecycline in combination with colistin, levofloxacin, amikacin and imipenem against five tigecycline non-susceptible <it>A. baumannii </it>strains, opening the way to a more rationale clinical assessment of novel combination therapies to combat infections caused by MDR and pan-resistant <it>A. baumannii</it>.</p>http://www.ann-clinmicrob.com/content/8/1/18 |
| spellingShingle | Petrosillo Nicola Capone Alessandro D'Arezzo Silvia Principe Luigi Visca Paolo <it>In vitro </it>activity of tigecycline in combination with various antimicrobials against multidrug resistant <it>Acinetobacter baumannii</it> Annals of Clinical Microbiology and Antimicrobials |
| title | <it>In vitro </it>activity of tigecycline in combination with various antimicrobials against multidrug resistant <it>Acinetobacter baumannii</it> |
| title_full | <it>In vitro </it>activity of tigecycline in combination with various antimicrobials against multidrug resistant <it>Acinetobacter baumannii</it> |
| title_fullStr | <it>In vitro </it>activity of tigecycline in combination with various antimicrobials against multidrug resistant <it>Acinetobacter baumannii</it> |
| title_full_unstemmed | <it>In vitro </it>activity of tigecycline in combination with various antimicrobials against multidrug resistant <it>Acinetobacter baumannii</it> |
| title_short | <it>In vitro </it>activity of tigecycline in combination with various antimicrobials against multidrug resistant <it>Acinetobacter baumannii</it> |
| title_sort | it in vitro it activity of tigecycline in combination with various antimicrobials against multidrug resistant it acinetobacter baumannii it |
| url | http://www.ann-clinmicrob.com/content/8/1/18 |
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