The purpose of this study was to identify the genes coding for resistance to ceftazidime and imipenem and describe the molecular epidemiology of A. baumannii strains isolated from a clinical center in Colombia. Twenty isolates of imipenem-resistant A. baumannii from an equal number of patients with nosocomial infections were obtained. Primers were used to amplify genes bla IMP, bla VIM, bla OXA...

ISAba1 is an insertion sequence that is widely distributed in Acinetobacter baumannii. We demonstrated here that ISAba1 and the composite transposon Tn2006 are capable of transposition, generating 9-bp target site duplications. The expression of the ISAba1 transposase-encoding gene was downregulated by translational frameshifting.

OBJECTIVES To explore the cause of third-generation cephalosporin resistance in Australian Acinetobacter baumannii isolates belonging to global clone 1 (GC1). METHODS GC1 isolates from Australia were tested for resistance to ceftazidime and cefotaxime using disc diffusion and MICs. PCR was used to determine the context of ISAba1-ampC configurations and amplicons were sequenced. The level of t...

Sir, Resistance to third-generation cephalosporins such as ceftazidime and cefotaxime in Acinetobacter baumannii is often due to increased expression of an intrinsic ampC gene. Expression increases when the ISAba1 insertion sequence (IS) is present in the appropriate orientation upstream of the ampC gene, providing an outward-facing promoter that appears to be stronger than the intrinsic promot...

in the GenBank non-redundant DNA database was examined. Two additional cases of ISAba1 associated with distinct ampC alleles were found in accession numbers EU604835 8 and AY325306. 3 In both of them, the IS was again in the same orientation and separated from the ATG initiation codon of ampC by 9 bp. The number of single nucleotide differences between the various ampC alleles is shown in Table...

Over-expression of AdeABC efflux pump stimulated continuously by the mutated AdeRS two component system has been found to result in antimicrobial resistance, even tigecycline (TGC) resistance, in multidrug-resistant Acinetobacter baumannii (MRAB). Although the insertion sequence, ISAba1, contributes to one of the AdeRS mutations, the detail mechanism remains unclear. In the present study we col...

D2 differed from one another by fewer than five single nucleotide differences, but only the WM98 sequence was not interrupted by large insertions or deletions (positions of insertions/deletions are indicated in Figure 1). AB307-0294 (GenBank accession number CP001172) was also identical over most of this span, but contained patches that differed and lacked a large span. The AB0057 sequence (Gen...

INTRODUCTION Acinetobacter baumannii is an important opportunistic pathogen responsible for causing nosocomial infections. Carbapenems are considered to be the drug of choice to treat infections caused by multidrug-resistant A. baumannii. The prevalent mechanism of carbapenem resistance in A. baumannii is enzymatic degradation by β-lactamases. Therefore, the aim of the study is to determine the...

PURPOSE The increasing prevalence and global spread of carbapenem-resistant Acinetobacter baumannii (A. baumannii) has become a serious problem. The aim of this study was to investigate molecular and epidemiological characteristics of carbapenem-resistant A. baumannii isolates collected from Korean non-tertiary hospitals. MATERIALS AND METHODS Thirty six non-duplicated carbapenem-resistant A....

In the last few years, phenotypically carbapenem resistant Acinetobacter strains have been identified throughout the world, including in many of the hospitals and intensive care units (ICUs) of Australia. Genotyping of Australian ICU outbreak-associated isolates by pulsed-field gel electrophoresis of whole genomic DNA indicated that different strains were cocirculating within one hospital. The ...