IN VITRO ΑΝΑΠΤΥΞΗ ΑΝΤΟΧΗΣ ΠΡΟΤΥΠΟΥ ΣΤΕΛΕΧΟΥΣ PSEUDOMONAS AERUGINOSA ΣΤΟ ΙΜΙΡΕΝΕΜ ΚΑΙ ΙΔΙΟΤΗΤΕΣ ΑΥΤΟΥ
A PROTOTYPE SENSITIVE STRAIN OF PSEUDOMONAS AERUGINOSA (IR) WAS "ADAPTED" IN VITRO TO IMIPENEM BY SERIAL TRANSFERS IN BROTH CONTAINING INCREASING CONCENTRATIONS OF ANTIBIOTIC AND UP TO 32MG/ML. 30 SERIAL SUBCULTURES OF THE RESISTANT PROGENY (IR-RES) IN ANTIBIOTIC FREE SOLID MEDIA RESULTED IN A PROGENY (IR-REV) WHICH WAS STILL RESISTANT AND EXHIBITED INDEPENDENT PROPERTIES. THIS TYPE OF IN VITRO RESISTANCE TO IMIPENEN AFFECTED GROWTH RATE, COLONY MORPHOLOGY, PIGMENT PRODUCTION, GROWTH OF 42 C AND GLUCOSE OXIDATION. BETA-LACTAMASE ASSAYS SHOWED THATTHE MOST LIKELY REASON FOR THE RESISTANCE WAS THE EXISTENCE OF AN INCREASE PERMEABILITY BARRIER WHOSE MECHANISM WAS CHIEFLY BASED UPON IRREVERSIBLE PROCESSES. THESE PROCESSES WERE THE ALTERATIONS IN O .M. PROTEINS LPS AND PHOSPHOLIPIDS.SDS-PAGE ANALYSIS OF THE OM PROTEINS REVEALED A MARKED DECREASE OF 5 PROTEINS WHOSE MW CORRESPOND TO PORIUS D1 AND P AND OMPS D2, H1 AND H2. PERMEATION OF IMIPENEM THROUGH PORIUS D1 SEEMS QUITE APPLICABLE. LPS CHEMICAL ANALYSIS REVEALEDA MARKED INCREASE IN KDO, TOTAL HEXOSES AND HEPTOSE CONSTITUENTS. THE PHOSPHOLIPID CONTENT OF THE OM WAS ALSO INCREASED THOUGH THE PHOSPHATE UPTAKE WAS MARKEDLY DECREASED IN THE RESISTANT STRAINS, A FINDING WHICH WAS CONCOMITANT WITH PORIN'S P ABSENCE. IMIPENEM RESISTANCE WAS ACCOMPANIED BY PARTIALLY REVERSIBLE CROSS-RESISTANCE TO DIBASIC PENAMS, CEPHENS AND AMINOGLYCOSIDES, BUT SENSITIVITY TO MONOBASIC PENANS, MONOBACTAMS AND POLYMYXIN-B REMAINED UNCHANGED. WE PROPOSEA "LOSS" MUTATION MECHANISM AS THE MOST POSSIBLE OVERALL MECHANISM FOR IN VITRO SELECTIVE RESISTANCE TO IMIPENEM IN P. AERUGINOSA.
Αντιβιοτικό, Αντοχή, ΕΞΩΤΕΡΙΚΗ ΜΕΜΒΡΑΝΗ, Ιατρική του ανθρώπου και των σπονδυλωτών, Μικροβιολογία, Antibiotic, Imipenem, Medicine (human and vertebrates), Microbiology, OUTER MEMBRANE, Pseudomonas aeruginosa, Resistance, Ιατρική και Επιστήμες Υγείας, Βασική Ιατρική, Κλινική Ιατρική, Medical and Health Sciences, Basic Medicine, Clinical Medicine
Networked Digital Library of Theses and Dissertations