title: 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.
abstract: 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.
authors.affiliation: CIBIACI and Department of Evolutionary Biology, University of Florence, Florence, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Donnarumma
authors.forename: Simona
authors.initials: S
authors.lastname: Sergi
authors.forename: Cristina
authors.initials: C
authors.lastname: Indorato
authors.forename: Giorgio
authors.initials: G
authors.lastname: Mastromei
authors.forename: Roberto
authors.initials: R
authors.lastname: Monnanni
authors.forename: Pieluigi
authors.initials: P
authors.lastname: Nicoletti
authors.forename: Patrizia
authors.initials: P
authors.lastname: Pecile
authors.forename: Daniela
authors.initials: D
authors.lastname: Cecconi
authors.forename: Roberta
authors.initials: R
authors.lastname: Mannino
authors.forename: Sara
authors.initials: S
authors.lastname: Bencini
authors.forename: Rosa
authors.initials: R
authors.lastname: Fanci
authors.forename: Alberto
authors.initials: A
authors.lastname: Bosi
authors.forename: Enrico
authors.initials: E
authors.lastname: Casalone
mesh_terms: 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
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D001618:beta-Lactamases