Molecular characterization of acinetobacter isolates collected in intensive care units of six hospitals in Florence, Italy, during a 3-year surveillance program: a population structure analysis.
The strain diversity and the population structure of nosocomial Acinetobacter isolated from patients admitted to different hospitals in Florence, Italy, during a 3-year surveillance program, were investigated by amplified fragment length polymorphism (AFLP). The majority of isolates (84.5%) were identified as A. baumannii, confirming this species as the most common hospital Acinetobacter. Three very distinct A. baumannii clonal groups (A1, A2, and A3) were defined. The A1 isolates appeared to be genetically related to the well-characterized European EU II clone. A2 was responsible for three outbreaks which occurred in two intensive care units. Space/time population dynamic analysis showed that A1 and A2 were successful nosocomial clones. Most of the A. baumannnii isolates were imipenem resistant. The genetic determinants of carbapenem resistance were investigated by multiplex PCR, showing that resistance, independently of hospital origin, period of isolation, or clonal group, was associated with the presence of a bla (OXA-58-like) gene and with ISAba2 and ISAba3 elements flanking this gene. bla (OXA-58) appeared to be horizontally transferred. This study showed that the high discriminatory power of AFLP is useful for identification and typing of nosocomial Acinetobacter isolates. Moreover the use of AFLP in a real-time surveillance program allowed us the recognition of clinically relevant and widespread clones and their monitoring in hospital settings. The correlation between clone diffusion, imipenem resistance, and the presence of the bla(OXA-58-like) gene is discussed.
Donnarumma
Francesca
F
CIBIACI and Department of Evolutionary Biology, University of Florence, Florence, Italy.
Sergi
Simona
S
Indorato
Cristina
C
Mastromei
Giorgio
G
Monnanni
Roberto
R
Nicoletti
Pieluigi
P
Pecile
Patrizia
P
Cecconi
Daniela
D
Mannino
Roberta
R
Bencini
Sara
S
Fanci
Rosa
R
Bosi
Alberto
A
Casalone
Enrico
E
D000150:Acinetobacter / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054458:Amplified Fragment Length Polymorphism Analysis; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D015780:Carbapenems / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D007362:Intensive Care Units; D007558:Italy / Q000453:epidemiology; D017720:Molecular Epidemiology; D011110:Polymorphism, Genetic; D055815:Young Adult; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D001618:beta-Lactamases