[Molecular characterization of Pseudomonas aeruginosa isolates in Cantabria, Spain, producing VIM-2 metallo-beta-lactamase].
BACKGROUND
Pseudomonas aeruginosa strains producing metallo-beta-lactamases (MbetaL) are uncommon in Spain. This study describes the characterization of 9 new clonally related multiresistant P. aeruginosa isolates possessing the bla(VIM-2) gene in Cantabria (Northern Spain).


METHODS
P. aeruginosa clinical strains (1 per patient) were isolated in the Microbiology Service of Marqués de Valdecilla University Hospital between January 2004 and December 2006. Identification and preliminary susceptibility studies were performed with the MicroScan WalkAway system (Dade Behring, Sacramento, CA) and results were verified by a microdilution reference method.


RESULTS
MICs of imipenem and meropenem for the 9 isolates ranged from 32 to 128 and 16 to 64 microg/mL, respectively. Nine isolates had a single Rep-PCR pattern and were intermediate or resistant to ceftazidime, cefepime, gentamicin, tobramycin, amikacin and ciprofloxacin. Eight of the 9 isolates were susceptible to aztreonam. Hydrolysis activity of imipenem in MbetaL-positive isolates ranged from 162+/-18 to 235+/-28 pmol/min/microg protein and was abolished in the presence of 5 mM EDTA. All isolates possessed an integron with genes aac(6')32, bla(VIM-2) and a putative transposase-encoding gene, flanked by the conserved 5'CS and 3'CS regions.


CONCLUSIONS
In the clinical isolates studied, the presence of MbetaL VIM-2 sufficed to explain their resistance to carbapenems.
Rodríguez
María-Cruz
MC
Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, Spain.
Ruiz del Castillo
Belén
B
Rodríguez-Mirones
Cristina
C
Romo
María
M
Monteagudo
Idoia
I
Martínez-Martínez
Luis
L
D000123:Acetyltransferases / Q000032:analysis / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D017124:Conserved Sequence; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D032023:Integrons / Q000235:genetics*; D008297:Male; D000077731:Meropenem; D008875:Middle Aged; D008969:Molecular Sequence Data; D018272:Porins / Q000737:chemistry / Q000235:genetics; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013030:Spain / Q000453:epidemiology; D013845:Thienamycins / Q000494:pharmacology; D019895:Transposases / Q000235:genetics; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000032:analysis* / Q000235:genetics
D001426:Bacterial Proteins; D018272:Porins; D013845:Thienamycins; C077157:OprD protein, Pseudomonas aeruginosa; D000123:Acetyltransferases; D019895:Transposases; C425108:beta-lactamase bla(vim-2); D001618:beta-Lactamases; D000077731:Meropenem