Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp.
Introduction: Pseudomonas aeruginosa and Acinetobcter spp. are important nosocomial pathogens and carbapenem resistance is an emerging threat. Therapeutic options for infections with these isolates include colistin. This study was conducted to determine the prevalence of carbapenem resistance in P....
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The Journal of Infection in Developing Countries
2013-11-01
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| Series: | Journal of Infection in Developing Countries |
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| Online Access: | https://jidc.org/index.php/journal/article/view/2924 |
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| author | Srujana Mohanty Vijeta Maurya Rajni Gaind Monorama Deb |
| author_facet | Srujana Mohanty Vijeta Maurya Rajni Gaind Monorama Deb |
| author_sort | Srujana Mohanty |
| collection | DOAJ |
| description | Introduction: Pseudomonas aeruginosa and Acinetobcter spp. are important nosocomial pathogens and carbapenem resistance is an emerging threat. Therapeutic options for infections with these isolates include colistin. This study was conducted to determine the prevalence of carbapenem resistance in P. aeruginosa and Acinetobacter spp. bloodstream isolates, phenotypically characterize the resistance mechanisms and evaluate the invitro activity of colistin.
Methodology: Consecutive 145 (95 P.aeruginosa and 50 Acinetobacter spp.) non-repeat isolates were included. Antibiotic susceptibility testing was performed per CLSI guidelines. MIC for carbapenems and colistin was performed using Etest. Isolates showing reduced susceptibility or resistance to the carbapenems were tested for metallo-β-lactamase (MBL) production using imipenem-EDTA combined disk and MBL Etest.
Results: Carbapenem resistance was observed in 40% P. aeruginosa and 66.0% Acinetobacter spp. Carbapenem-resistant (CA-R) isolates were significantly (p< 0.05) more frequently resistant to the other antibiotics than carbapenem-susceptible isolates. Approximately half of the CA-R strains were multidrug-resistant, and 3.1-5.5% were resistant to all antibiotics tested. MBL was found in 76.3% and 69.7% of the P. aeruginosa and Acinetobacter spp., respectively. Colistin resistance was observed in three (6.0%) Acinetobacter isolates and eight (8.4%) P. aeruginosa. MIC50 for carbapenems were two to four times higher for MBL-positive compared to MBL-negative isolates, but no difference was seen in MIC for colistin.
Conclusion: Carbapenem resistance was observed to be mediated by MBL in a considerable number of isolates. Colistin is an alternative for infections caused by CA-R isolates; however, MIC testing should be performed whenever clinical use of colistin is considered.
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| format | Article |
| id | doaj-art-ab74fbd90df14b72957e010d411dad3a |
| institution | OA Journals |
| issn | 1972-2680 |
| language | English |
| publishDate | 2013-11-01 |
| publisher | The Journal of Infection in Developing Countries |
| record_format | Article |
| series | Journal of Infection in Developing Countries |
| spelling | doaj-art-ab74fbd90df14b72957e010d411dad3a2025-08-20T02:27:09ZengThe Journal of Infection in Developing CountriesJournal of Infection in Developing Countries1972-26802013-11-0171110.3855/jidc.2924Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp.Srujana Mohanty0Vijeta Maurya1Rajni Gaind2Monorama Deb3Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, IndiaVardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, IndiaVardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, IndiaVardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, IndiaIntroduction: Pseudomonas aeruginosa and Acinetobcter spp. are important nosocomial pathogens and carbapenem resistance is an emerging threat. Therapeutic options for infections with these isolates include colistin. This study was conducted to determine the prevalence of carbapenem resistance in P. aeruginosa and Acinetobacter spp. bloodstream isolates, phenotypically characterize the resistance mechanisms and evaluate the invitro activity of colistin. Methodology: Consecutive 145 (95 P.aeruginosa and 50 Acinetobacter spp.) non-repeat isolates were included. Antibiotic susceptibility testing was performed per CLSI guidelines. MIC for carbapenems and colistin was performed using Etest. Isolates showing reduced susceptibility or resistance to the carbapenems were tested for metallo-β-lactamase (MBL) production using imipenem-EDTA combined disk and MBL Etest. Results: Carbapenem resistance was observed in 40% P. aeruginosa and 66.0% Acinetobacter spp. Carbapenem-resistant (CA-R) isolates were significantly (p< 0.05) more frequently resistant to the other antibiotics than carbapenem-susceptible isolates. Approximately half of the CA-R strains were multidrug-resistant, and 3.1-5.5% were resistant to all antibiotics tested. MBL was found in 76.3% and 69.7% of the P. aeruginosa and Acinetobacter spp., respectively. Colistin resistance was observed in three (6.0%) Acinetobacter isolates and eight (8.4%) P. aeruginosa. MIC50 for carbapenems were two to four times higher for MBL-positive compared to MBL-negative isolates, but no difference was seen in MIC for colistin. Conclusion: Carbapenem resistance was observed to be mediated by MBL in a considerable number of isolates. Colistin is an alternative for infections caused by CA-R isolates; however, MIC testing should be performed whenever clinical use of colistin is considered. https://jidc.org/index.php/journal/article/view/2924carbapenem resistancePseudomonas aeruginosaAcinetobacter spp.metallo-β-lactamasecolistin susceptibility and MIC |
| spellingShingle | Srujana Mohanty Vijeta Maurya Rajni Gaind Monorama Deb Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp. Journal of Infection in Developing Countries carbapenem resistance Pseudomonas aeruginosa Acinetobacter spp. metallo-β-lactamase colistin susceptibility and MIC |
| title | Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp. |
| title_full | Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp. |
| title_fullStr | Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp. |
| title_full_unstemmed | Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp. |
| title_short | Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp. |
| title_sort | phenotypic characterization and colistin susceptibilities of carbapenem resistant of pseudomonas aeruginosa and acinetobacter spp |
| topic | carbapenem resistance Pseudomonas aeruginosa Acinetobacter spp. metallo-β-lactamase colistin susceptibility and MIC |
| url | https://jidc.org/index.php/journal/article/view/2924 |
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