[Incidence and resistance patterns of pathogens from lower respiratory tract infections (LRTI)].

The aim of present study was to evaluate the incidence and antibiotic susceptibility of pathogens in LRTI for patients in ICU/Surgery and pneumological wards from Marius Nasta Institute. A number of 938 strains isolated between September 1st 2004 and September 1st 2005 were identified by standard procedures and antimicrobial resistance was determined following CLSI approved standard. Imipenem-EDTA Double Disk Synergy test and Etest were used for detection of metallo-beta-lactamase producing isolates of P.aeruginosa. There were isolated 744 Gram-negative strains: H. influenzae 34.6%, P. aeruginosa 17.7%, H. parainfluenzae 15.9%, K. pneumoniae 8.6% and another spp. and 194 Gram-positive strains: 54.1% S.aureus and 45.9% S.pneumoniae. Among H. influenzae and H. parainfluenzae isolates, the highest resistance rate was to trimethoprim/sulfametoxazole (SXT 30.9% and 31.1%), followed by ampicillin (AMP 11.6% and 13.4%), chloramphenicol (C 4.5% and 5.1%) and clarithromycin (1.6% and 13.6%). P. aeruginosa strains showed a resistance rate between 7.9% to amikacin and 38.3% to cefoperazone. The resistance to imipenem (IPM) and meropenem (MEM) was close: 28.2% and 26.0%. From 36 P. aeruginosa IPM and multidrug resistant strains tested, 8 were probably producing metallo-beta-lactamase. For S. aureus the highest resistance rate was to penicillin 93.3% followed by erythromycin (E 45.7%), oxacillin 41.9% and CIP (33.3%); all strains were susceptible to vancomycin, teicoplanin and linezolid. From S. pneumoniae strains 13.4% were high resistant to penicillin and 39.3% were intermediate resistant. The resistance rate for other antibacterial agents was 64.0% to SXT, 18.8% to E, 8.3% to C and all strains were susceptible to levofloxacin. K. pneumoniae strains were resistant to cefepime (11.3%), CIP (7.8%) and there was no resistant strain to IPM and MEM.