Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of <it>Acinetobacter baumannii</it>
<p>Abstract</p> <p>Background</p> <p><it>Acinetobacter baumannii </it>is emerging as an important nosocomial pathogen. Multidrug resistance, as well as ability to withstand environmental stresses, makes eradication of <it>A. baumannii </it>diffic...
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| Format: | Article |
| Language: | English |
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BMC
2009-12-01
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| Series: | BMC Microbiology |
| Online Access: | http://www.biomedcentral.com/1471-2180/9/270 |
| _version_ | 1818148127347048448 |
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| author | Giacobone Ernesto Migliavacca Roberta Fugazza Giulia Steffanoni Laura Nucleo Elisabetta Navarra Antonella Pagani Laura Landini Paolo |
| author_facet | Giacobone Ernesto Migliavacca Roberta Fugazza Giulia Steffanoni Laura Nucleo Elisabetta Navarra Antonella Pagani Laura Landini Paolo |
| author_sort | Giacobone Ernesto |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p><it>Acinetobacter baumannii </it>is emerging as an important nosocomial pathogen. Multidrug resistance, as well as ability to withstand environmental stresses, makes eradication of <it>A. baumannii </it>difficult, particularly from hospital settings.</p> <p>Results</p> <p>Over a six-year period, 73 isolates of <it>A. baumannii </it>were collected from infected patients in two hospitals in Italy. While 69 out of the 73 isolates displayed identical multidrug antibiotic resistance pattern, they were susceptible to carbapenems. Genetic profiles of these 69 isolates, determined by Pulsed Field Gel Electrophoresis (PFGE), indicated that they were genetically related and could be clustered in a specific clone, called SMAL. We tested the ability of the SMAL clone to form biofilm, an important determinant for bacterial colonization of the human host and for persistence in the hospital environment. Biofilm formation by <it>A. baumannii </it>SMAL, measured as surface adhesion to polystyrene, is strongly affected by growth conditions, being impaired in rich growth media such as LB, while being favoured in glucose-based medium. Surface adhesion in glucose-based media is inhibited by treatment with cellulase, suggesting that it depends on production of cellulose or of a chemically related extracellular polysaccharide. Exposure of <it>A. baumannii </it>SMAL to subinhibitory concentrations of imipenem resulted in biofilm stimulation and increased production of iron uptake proteins. Growth in iron-supplemented medium also stimulated surface adhesion, thus suggesting that increased intracellular iron concentrations might act as an environmental signal for biofilm formation in <it>A. baumannii </it>SMAL.</p> <p>Conclusions</p> <p>Our results indicate that exposure to subinhibitory concentrations of imipenem can stimulate biofilm formation and induce iron uptake in a pathogenic strain of <it>A. baumannii</it>, with potential implications on antibiotic susceptibility and ability to persist in the human host.</p> |
| first_indexed | 2024-12-11T12:46:12Z |
| format | Article |
| id | doaj.art-fd4d7b9792e44322b6dca0fe159e8915 |
| institution | Directory Open Access Journal |
| issn | 1471-2180 |
| language | English |
| last_indexed | 2024-12-11T12:46:12Z |
| publishDate | 2009-12-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Microbiology |
| spelling | doaj.art-fd4d7b9792e44322b6dca0fe159e89152022-12-22T01:06:49ZengBMCBMC Microbiology1471-21802009-12-019127010.1186/1471-2180-9-270Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of <it>Acinetobacter baumannii</it>Giacobone ErnestoMigliavacca RobertaFugazza GiuliaSteffanoni LauraNucleo ElisabettaNavarra AntonellaPagani LauraLandini Paolo<p>Abstract</p> <p>Background</p> <p><it>Acinetobacter baumannii </it>is emerging as an important nosocomial pathogen. Multidrug resistance, as well as ability to withstand environmental stresses, makes eradication of <it>A. baumannii </it>difficult, particularly from hospital settings.</p> <p>Results</p> <p>Over a six-year period, 73 isolates of <it>A. baumannii </it>were collected from infected patients in two hospitals in Italy. While 69 out of the 73 isolates displayed identical multidrug antibiotic resistance pattern, they were susceptible to carbapenems. Genetic profiles of these 69 isolates, determined by Pulsed Field Gel Electrophoresis (PFGE), indicated that they were genetically related and could be clustered in a specific clone, called SMAL. We tested the ability of the SMAL clone to form biofilm, an important determinant for bacterial colonization of the human host and for persistence in the hospital environment. Biofilm formation by <it>A. baumannii </it>SMAL, measured as surface adhesion to polystyrene, is strongly affected by growth conditions, being impaired in rich growth media such as LB, while being favoured in glucose-based medium. Surface adhesion in glucose-based media is inhibited by treatment with cellulase, suggesting that it depends on production of cellulose or of a chemically related extracellular polysaccharide. Exposure of <it>A. baumannii </it>SMAL to subinhibitory concentrations of imipenem resulted in biofilm stimulation and increased production of iron uptake proteins. Growth in iron-supplemented medium also stimulated surface adhesion, thus suggesting that increased intracellular iron concentrations might act as an environmental signal for biofilm formation in <it>A. baumannii </it>SMAL.</p> <p>Conclusions</p> <p>Our results indicate that exposure to subinhibitory concentrations of imipenem can stimulate biofilm formation and induce iron uptake in a pathogenic strain of <it>A. baumannii</it>, with potential implications on antibiotic susceptibility and ability to persist in the human host.</p>http://www.biomedcentral.com/1471-2180/9/270 |
| spellingShingle | Giacobone Ernesto Migliavacca Roberta Fugazza Giulia Steffanoni Laura Nucleo Elisabetta Navarra Antonella Pagani Laura Landini Paolo Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of <it>Acinetobacter baumannii</it> BMC Microbiology |
| title | Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of <it>Acinetobacter baumannii</it> |
| title_full | Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of <it>Acinetobacter baumannii</it> |
| title_fullStr | Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of <it>Acinetobacter baumannii</it> |
| title_full_unstemmed | Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of <it>Acinetobacter baumannii</it> |
| title_short | Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of <it>Acinetobacter baumannii</it> |
| title_sort | growth in glucose based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug resistant clinical isolate of it acinetobacter baumannii it |
| url | http://www.biomedcentral.com/1471-2180/9/270 |
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