Population structure and antibiotic resistance of Acinetobacter DNA group 2 and 13TU isolates from hospitals in the UK

Abstract

A total of 287 Acinetobacter isolates belonging to DNA groups 2 (A. baumannii) and 13TU was collected consecutively from 46 hospitals and typed by randomly amplified polymorphic DNA fingerprinting with primers DAF-4 and ERIC-2. With a similarity coefficient of >72% as a cut-off value, 37 clusters of genotypically similar isolates (genotypes) were recognised. Four major clusters, found in 15, 12, 12 and 8 hospitals respectively, accounted for 42% of isolates, but only three of these predominant clusters were associated with outbreaks of infection in individual hospitals. Many of the isolates were resistant to multiple antibiotics, including expanded-spectrum â-lactam agents, aminoglycosides, tetracyclines and fluoroquinolones, but >98% remained susceptible to carbapenems and colistin. Overall, the study demonstrated that a heterogeneous population of Acinetobacter DNA group 2 and 13TU isolates, frequently showing multiple resistance to antibiotics, was causing infections in UK hospitals, and that four predominant genotypes appeared to have disseminated among geographically distinct locations.

Species-Level Identification of Isolates of the Acinetobacter calcoaceticus - Acinetobacter baumannii Complex by Sequence Analysis of the 16S-23S rRNA Gene Spacer Region

“…Therefore, precise identification of the species in the A. calcoaceticus-A. baumannii complex is important to elucidate the ecology, epidemiology, and pathology of these species; and practical identification methods must be developed for this purpose (25,41).Phenotypic identification of Acinetobacter isolates to the species level has proven to be insufficient (15, 21). However, several genotypic methods have been developed for (genomic) species identification of acinetobacters, including the A. calcoaceticus-A.…”

“…appeared to be the eighth most common cause of nosocomial pneumonia (17). Nosocomial acinetobacters are notorious for their resistance to antibiotics, and strains resistant to most or all clinically important antibiotics, including expended-spectrum ␤-lactams and carbapenems, have now been identified worldwide (1,5,11,26,41).The genus Acinetobacter currently contains up to 33 described named and unnamed (genomic) species (9, 35). Of these, Acinetobacter calcoaceticus, A. baumannii, and genomic species 3 and 13TU are genetically and phenotypically very similar (21), which has led to the proposal to lump these and two closely related genomic species (genomic species close to 13TU and genomic species between 1 and 3) into the A. calcoaceticus-A.…”

“…Therefore, precise identification of the species in the A. calcoaceticus-A. baumannii complex is important to elucidate the ecology, epidemiology, and pathology of these species; and practical identification methods must be developed for this purpose (25,41).…”

Safety Assessment of Transgenic Organisms, Volume 4

“…However, it does not preclude the use of other molecular techniques based on PCR such as RAPD, AFLP, REP-PCR, ERIC-PCR and MLST, listed in Table 4. Random (as in RAPD, random amplified polymorphic DNA) or specific (as in AFLP) amplification of a highly variable region of the genome are two methods with lower discriminatory power than PFGE (Silbert et al, 2004) that can be used to differentiate strains within species from both clinical and environmental samples (Carr et al, 2001a;Spence et al, 2002Spence et al, , 2004. REP-PCR (repetitive extragenic palindromic sequence-based PCR) and ERIC-PCR (Enterobacterial repetitive intergenic consensus-based) are two methods with a discriminatory power that is similar to each other and to ribotyping (Liu and Wu, 1997) but lower than that of PFGE (Silbert et al, 2004).…”

“…Acinetobacter species 13 was responsible for a case of bacteraemia following heart surgery (Mesnard et al, 1994). Population structure and antibiotic resistance of A. baumannii and 13TU isolates from hospitals in the UK have been studied by RAPD (Spence et al, 2002). The persistence and clonal spread of a single strain of Acinetobacter 13TU in a large Scottish teaching hospital was analyzed by PFGE (McDonald et al, 1999).…”