The sequences of seven class D β-lactamases isolated from carbapenem-resistant Acinetobacter baumannii from four continents

Brown, Susan; Amyes, S. G. B.

doi:10.1111/j.1469-0691.2005.01096.x

Cited by 75 publications

(62 citation statements)

References 21 publications

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“…Some of these variants had also been identified in carbapenem-resistant A. baumannii isolates disseminated worldwide (21,47,158). Up to 45 OXA-51/ OXA-69 variants are now known (Table 1), and most if not all probably have identical biochemical properties.…”

Section: Naturally Occurring Class D ␤-Lactamasesmentioning

confidence: 99%

Diversity, Epidemiology, and Genetics of Class D β-Lactamases

Poirel

Naas

Nordmann

2010

Antimicrob Agents Chemother

553

485

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Class D ␤-lactamase-mediated resistance to ␤-lactams has been increasingly reported during the last decade. Those enzymes also known as oxacillinases or OXAs are widely distributed among Gram negatives. Genes encoding class D ␤-lactamases are known to be intrinsic in many Gram-negative rods, including Acinetobacter baumannii and Pseudomonas aeruginosa, but play a minor role in natural resistance phenotypes. The OXAs (ca. 150 variants reported so far) are characterized by an important genetic diversity and a great heterogeneity in terms of ␤-lactam hydrolysis spectrum. The acquired OXAs possess either a narrow spectrum or an expanded spectrum of hydrolysis, including carbapenems in several instances. Acquired class D ␤-lactamase genes are mostly associated to class 1 integron or to insertion sequences.

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Section: Naturally Occurring Class D ␤-Lactamasesmentioning

confidence: 99%

Diversity, Epidemiology, and Genetics of Class D β-Lactamases

Poirel

Naas

Nordmann

2010

Antimicrob Agents Chemother

553

485

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“…Furthermore, it is present in the type strain, isolated decades ago. GenBank submissions describing variants are from isolates of A. baumannii from many different countries (France, Greece, Turkey, Spain, United Kingdom, South Africa, Hong Kong, Singapore, and Argentina) (e.g., DQ335566 and DQ445683) distributed over four continents (1), clearly suggesting bla OXA-51-like is ubiquitous in A. baumannii.…”

Section: All Class 1 Integrase Negativementioning

confidence: 99%

Identification of Acinetobacter baumannii by Detection of the bla _OXA-51-like Carbapenemase Gene Intrinsic to This Species

Turton¹,

Woodford²,

Glover³

et al. 2006

J Clin Microbiol

574

397

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bla OXA-51-like was sought in clinical isolates of Acinetobacter species in a multiplex PCR, which also detects bla OXA-23-like and class 1 integrase genes. All isolates that gave a band for bla OXA-51-like identified as A. baumannii . This gene was detected in each of 141 isolates of A. baumannii but not in those of 22 other Acinetobacter species.

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“…Recently, the number of OXA-type carbapenemases has increased substantially, and they have been divided into eight distantly related groups (39). Of these OXAtype carbapenemases, the OXA-51-like group consists of a large number of closely related variants from a wide range of geographical origins (4,5). Furthermore, there is increasing evidence that A. baumannii encodes a naturally occurring carbapenemase gene, bla , that is intrinsic to the species (15,22,37,41).…”

mentioning

confidence: 99%

An OXA-66/OXA-51-Like Carbapenemase and Possibly an Efflux Pump Are Associated with Resistance to Imipenem in Acinetobacter baumannii

Hu¹,

Yao²,

Fung³

et al. 2007

Antimicrob Agents Chemother

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We investigated the mechanisms involved in imipenem resistance in 23 clinical strains of Acinetobacter baumannii. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed the presence of a 30-kDa protein in imipenem-intermediate A. baumannii (IIAB) and imipenem-resistant A. baumannii (IRAB) strains; this protein was almost undetectable in imipenem-susceptible A. baumannii (ISAB) strains. The 30-kDa protein was identified as an OXA-51-like carbapenemase using two-dimensional gel electrophoresis and mass spectrometry. Similar to other recent findings, bla OXA-51-like genes were found to exist in all 23 clinical strains; however, the transcript levels of bla OXA-51-like in the IIAB and IRAB were higher than in the ISAB strains using reverse transcriptase PCR (RT-PCR) and real-time RT-PCR assays. This change was due to the presence of an insertion sequence, ISAba1, upstream of bla OXA-51-like in the IIAB and IRAB strains that was not present in the ISAB strains. The introduction of bla OXA-66 (a bla OXA-51-like gene), identified in ISAB ab1254 and IRAB ab1266, into Escherichia coli TOP10 cells resulted in 3.95-fold and 7.90-fold elevations in resistance to imipenem, respectively. Furthermore, when ISAB ab8 and ISAB ab1254 and their in vitro-selected imipenem-resistant mutants ISAB ab8(r) and ISAB ab1254(r) were compared, the results showed no change in the bla OXA-66 /bla OXA-51-like gene sequences, in expression of the gene, and in the outer membrane protein profiles. However, there was a four-to eightfold reduction in imipenem resistance upon adding carbonyl cyanide m-chlorophenylhydrazone. Taken together, these results suggest that the OXA-66/OXA-51-like carbapenemase contributes to intrinsic resistance to imipenem; however, drug export by an efflux pump may be more important and/or occur more frequently in imipenem-resistant A. baumannii. Furthermore, this is the first report of a Taiwanese strain of an OXA-66/OXA-51-like carbapenemase that confers imipenem resistance in A. baumannii.Acinetobacter baumannii accounts for a large percentage of nosocomial infections including pneumonia, bacteremia, skin infections, wound infections, and urinary tract infections (2, 19). Increasingly, multidrug resistance strains of A. baumannii have become common in hospitals worldwide and especially in intensive care units (10, 12, 30) and burn units (2,31,32,40). The types of resistance include many commonly used antibiotics such as aminoglycosides, fluoroquinolones, and ␤-lactams, although carbapenems are the most used antimicrobial drugs. However, an increasing number of recent studies reported the emergence of clinical A. baumannii strains that are resistance to imipenem (7,9,27).The mechanism of resistance to carbapenems in A. baumannii has mostly been ascribed to the acquisition of carbapenemases (1, 26) or to synergistic effects between ␤-lactamases with an ability to hydrolyze carbapenems and decreased expression of certain penicillin-binding proteins (13,14). The carbapenemases in A. baumannii ...

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The sequences of seven class D β-lactamases isolated from carbapenem-resistant Acinetobacter baumannii from four continents

Cited by 75 publications

References 21 publications

Diversity, Epidemiology, and Genetics of Class D β-Lactamases

Diversity, Epidemiology, and Genetics of Class D β-Lactamases

Identification of Acinetobacter baumannii by Detection of the bla _OXA-51-like Carbapenemase Gene Intrinsic to This Species

An OXA-66/OXA-51-Like Carbapenemase and Possibly an Efflux Pump Are Associated with Resistance to Imipenem in Acinetobacter baumannii

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The sequences of seven class D β-lactamases isolated from carbapenem-resistant Acinetobacter baumannii from four continents

Cited by 75 publications

References 21 publications

Diversity, Epidemiology, and Genetics of Class D β-Lactamases

Diversity, Epidemiology, and Genetics of Class D β-Lactamases

Identification of Acinetobacter baumannii by Detection of the bla OXA-51-like Carbapenemase Gene Intrinsic to This Species

An OXA-66/OXA-51-Like Carbapenemase and Possibly an Efflux Pump Are Associated with Resistance to Imipenem in Acinetobacter baumannii

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Identification of Acinetobacter baumannii by Detection of the bla _OXA-51-like Carbapenemase Gene Intrinsic to This Species