Study of outer membrane proteins (OMPS) and their role in co-modulation of resistance in non typhoidic Salmonella strains isolated in Iaşi.
OBJECTIVE
To characterize the OMP profile and to study the possible interference with other resistance determinants.


METHODS
16 non-typhoidic Salmonella strains, isolated in 1999 from stools of pediatric patients, were selected according to their resistance phenotype: resistance to Ampicillin (AMP), Amoxycillin/Clavulanic Acid (AMC), and third generation cephalosporins: Ceftriaxone (CRO) and Ceftazidime (CAZ). Identification and sensitivity testing were done by DADE MicroScan System. beta-Lactamases were characterized by isoelectric focusing (IEF) with preformed minigelss. OMPs were studied on membrane preparations on SDS-urea gels.


RESULTS
Isoelectric points: Majority of the isolates had the association 5.4 +/- 7.6 (3/16) or 5.4 + 8.2 (6/16). The second beta-lactamase has the capacity to hydrolyse CAZ. We found three different patterns of OMPs: I: 30, 29 and 25 kDa; II: 30, 26 and 24 kDa; III: 30 and 25 kDa. We couldn't find any correlation between the OMPs profile and resistance phenotype, showing that the beta-lactamase production is the only resistant determinant.


CONCLUSIONS
The study shows the high frequency of extended-spectrum beta-lactamases (ES beta LA) amongst the non-typhoidic Salmonella; association of TEM type and ES beta LA enzymes diminishes considerably the therapeutic resources: inhibitor associated combinations are non effective. In non-typhoidic Salmonella, porins seems to have no influence in co-modulation of resistance.
Filip
R
R
Dept. of Microbiology, Faculty of Medicine, University of Medicine and Pharmacy Gr.T. Popa Iaşi.
Chihu-Amparan
L
L
Coman
G
G
Silva-Sanchez
J
J
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000502:physiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D010406:Penicillins / Q000494:pharmacology; D012383:Romania / Q000453:epidemiology; D012475:Salmonella / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology*; D001618:beta-Lactamases / Q000096:biosynthesis*; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D010406:Penicillins; D047090:beta-Lactams; D001618:beta-Lactamases