Cloning, Nucleotide Sequencing, and Analysis of the Gene Encoding an AmpC β-Lactamase in
            <i>Acinetobacter baumannii</i>

Bou, Germán; Martı́nez-Beltrán, J

doi:10.1128/aac.44.2.428-432.2000

Cited by 163 publications

(128 citation statements)

References 29 publications

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“…The enzymes belong to the functional group I [according to the Bush-Jacoby-Medeiros (B-J-M) classification] and the molecular class C. The A. baumannii bacterium is equipped with the chromosome encoded enzyme of class C, and ampC genes from heterogeneous A. baumannii strains highly correlate with each other, but differ from those from other types of strains. Thus, these enzymes are termed as the ADC family (7).…”

Section: Discussionmentioning

confidence: 99%

“…According to the instructions provided with the bacteria DNA extracting kit (Tiangen Biochemical Technology Co., Ltd., Beijing, China), DNA samples of the clinical strains were extracted as a PCR template. The primers used for PCR amplification (7 pairs created by Shenggong Corp., Shanghai, China) were as previously reported (6,7) and are presented in Table I. PCR was performed with a final volume of 25 µl.…”

Section: Detection Of Ampc β-Lactamases In Acinetobacter Baumanniimentioning

confidence: 99%

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Detection of AmpC β-lactamases in Acinetobacter baumannii in the Xuzhou region and analysis of drug resistance

Liu

2015

Experimental and Therapeutic Medicine

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Abstract. The aim of the present study was to determine the prevalence and related drug resistance of AmpC β-lactamases in Acinetobacter baumannii in tertiary-level hospitals in the Xuzhou region in China. A total of 134 clinical isolates of non-repetitive Acinetobacter baumannii were collected from different hospitals in the Xuzhou region, and multiplex polymerase chain reaction (PCR) was employed to determine the genotype of AmpC. The PCR products were purified and sequenced. The susceptibility to antibiotics was tested using the biometrics automated microbiological-assay system, VITEK-2. Amongst the 134 isolated strains, 96 strains were found to produce AmpC β-lactamases, and the positive rate was 72%, all of which carried acinetobacter-derived cephalosporinase (ADC) type AmpC resistance genes. The drug sensitivity tests indicated that the positive Acinetobacter baumannii strains were resistant to the majority of extended-spectrum β-lactam antibiotics, but were only sensitive to polymyxin. In conclusion, the incidence of AmpC enzymes in Acinetobacter baumannii strains in tertiary-level hospitals in the Xuzhou area is relatively high, and resistance to the majority of extendedspectrum β-lactam antibiotics may be related to the ADC type of AmpC.

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Section: Discussionmentioning

confidence: 99%

Section: Detection Of Ampc β-Lactamases In Acinetobacter Baumanniimentioning

confidence: 99%

Detection of AmpC β-lactamases in Acinetobacter baumannii in the Xuzhou region and analysis of drug resistance

Liu

2015

Experimental and Therapeutic Medicine

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“…baumannii produces an intrinsic AmpC-type cephalosporinase that is normally expressed at a low level and does not modify the efficacy of expanded-spectrum cephalosporins or carbapenems (1). Insertion of ISAba1 (belonging to the IS4 family) upstream of the bla ampC gene enhances expression by providing promoter sequences, resulting in resistance to expanded-spectrum cephalosporins (2,3).…”

Section: Naturally-occurring B-lactamasesmentioning

confidence: 99%

Genetic basis of antibiotic resistance in pathogenic Acinetobacter species

2011

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SummaryAntibiotic resistance in Acinetobacter spp., particularly Acinetobacter baumannii, is increasing rapidly. A. baumannii possesses two intrinsic b-lactamase genes, in addition to weak permeability and efflux systems, that together confer a natural reduced susceptibility to antibiotics. In addition, numerous acquired mechanisms of resistance have been identified in A. baumannii. The very high genetic plasticity of A. baumannii allows an accumulation of resistance determinants that give rise to multidrug resistance at an alarming rate. The role of novel genetic elements, such as resistance islands, in concentrating antibiotic resistance genes in A. baumannii requires detailed investigation in the near future.

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“…baumannii is a nosocomial pathogen associated with severe infections in immunocompromised hosts (19). Besides its chromosomally encoded AmpC-type beta lactamase (20), A. baumannii frequently harbors class B and D carbapenemases (21) and extended-spectrum beta-lactamases (ESBL) of the PER, GES, and VEB types (22). RNDtype efflux systems, including AdeABC (23), AdeIJK (24), and AdeFGH (25), further contribute to the multidrug resistance phenotype of clinical isolates.…”

mentioning

confidence: 99%

Structure and Function of the PiuA and PirA Siderophore-Drug Receptors from Pseudomonas aeruginosa and Acinetobacter baumannii

Moynié

Lüscher

Rolo

et al. 2017

Antimicrob Agents Chemother

106

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The outer membrane of Gram-negative bacteria presents an efficient barrier to the permeation of antimicrobial molecules. One strategy pursued to circumvent this obstacle is to hijack transport systems for essential nutrients, such as iron. BAL30072 and MC-1 are two monobactams conjugated to a dihydroxypyridone siderophore that are active against Pseudomonas aeruginosa and Acinetobacter baumannii. Here, we investigated the mechanism of action of these molecules in A. baumannii. We identified two novel TonB-dependent receptors, termed Ab-PiuA and Ab-PirA, that are required for the antimicrobial activity of both agents. Deletion of either piuA or pirA in A. baumannii resulted in 4-to 8-fold-decreased susceptibility, while their overexpression in the heterologous host P. aeruginosa increased susceptibility to the two siderophore-drug conjugates by 4-to 32-fold. The crystal structures of PiuA and PirA from A. baumannii and their orthologues from P. aeruginosa were determined. The structures revealed similar architectures; however, structural differences between PirA and PiuA point to potential differences between their cognate siderophore ligands. Spontaneous mutants, selected upon exposure to BAL30072, harbored frameshift mutations in either the ExbD3 or the TonB3 protein of A. baumannii, forming the cytoplasmic-membrane complex providing the energy for the siderophore translocation process. The results of this study provide insight for the rational design of novel siderophore-drug conjugates against problematic Gramnegative pathogens.

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Cloning, Nucleotide Sequencing, and Analysis of the Gene Encoding an AmpC β-Lactamase in Acinetobacter baumannii

Cited by 163 publications

References 29 publications

Detection of AmpC β-lactamases in Acinetobacter baumannii in the Xuzhou region and analysis of drug resistance

Detection of AmpC β-lactamases in Acinetobacter baumannii in the Xuzhou region and analysis of drug resistance

Genetic basis of antibiotic resistance in pathogenic Acinetobacter species

Structure and Function of the PiuA and PirA Siderophore-Drug Receptors from Pseudomonas aeruginosa and Acinetobacter baumannii

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