Dissemination of amikacin resistance gene aphA6 in Acinetobacter spp

Lambert, Thierry; Gerbaud, Guy; Bouvet, Philippe; Vieu, J.F.; Courvalin, Patrice

doi:10.1128/aac.34.6.1244

Cited by 45 publications

(39 citation statements)

References 23 publications

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“…(268). Earlier studies of the distribution of aminoglycoside resistance genes demonstrated the presence of aph(3Ј)-VIa in 83 to 95% of amikacin-resistant Acinetobacter strains (156,268). In a subsequent survey, the gene was identified in 46% of aminoglycoside-resistant Acinetobacter strains (188).…”

Section: Aminoglycoside Phosphotransferasesmentioning

confidence: 99%

Versatility of Aminoglycosides and Prospects for Their Future

2003

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Aminoglycoside antibiotics have had a major impact on our ability to treat bacterial infections for the past half century. Whereas the interest in these versatile antibiotics continues to be high, their clinical utility has been compromised by widespread instances of resistance. The multitude of mechanisms of resistance is disconcerting but also illuminates how nature can manifest resistance when bacteria are confronted by antibiotics. This article reviews the most recent knowledge about the mechanisms of aminoglycoside action and the mechanisms of resistance to these antibiotics

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Section: Aminoglycoside Phosphotransferasesmentioning

confidence: 99%

Versatility of Aminoglycosides and Prospects for Their Future

2003

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“…Lately, numerous outbreaks of nosocomial infections caused by A. baumannii have been reported (7-10, 16, 42, 47, 56, 57, 73), which are of particular concern because of the widespread and increasing antibiotic resistance of the isolated strains (17,30,32,33,40,41,48). Nevertheless, most infections have occurred in patients compromised by either antibiotic therapy, respiratory instrumentation and manipulations, dialysis, or surgery (18,19,39,70).…”

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“…anitratus (15), belongs to a bacterial species that is widely distributed throughout the environment (6). This microorganism can be isolated from the skin (3, 43) and respiratory tract (59) of healthy ambulatory adults as well as from hospital personnel and equipment (36,39,46,67).Lately, numerous outbreaks of nosocomial infections caused by A. baumannii have been reported (7-10, 16, 42, 47, 56, 57, 73), which are of particular concern because of the widespread and increasing antibiotic resistance of the isolated strains (17,30,32,33,40,41,48). Nevertheless, most infections have occurred in patients compromised by either antibiotic therapy, respiratory instrumentation and manipulations, dialysis, or surgery (18,19,39,70).…”

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Characterization of a high-affinity iron transport system in Acinetobacter baumannii

et al. 1992

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Analysis of a clinical isolate ofAcinetobacter baumannii showed that this bacterium was able to grow under iron-limiting conditions, using chemically defined growth media containing different iron chelators such as human transferrin, ethylenediaminedi-(o-hydroxyphenyl)acetic acid, nitrilotriacetic acid, and 2,2'-bipyridyl. This iron uptake-proficient phenotype was due to the synthesis and secretion of a catechol-type siderophore compound. Utilization bioassays using the SalmoneUla typhimurium iron uptake mutants enb-1 and enb-7 proved that this siderophore is different from enterobactin. This catechol siderophore was partially purified from culture supernatants by adsorption chromatography using an XAD-7 resin. The purified component exhibited a chromatographic behavior and a UV-visible light absorption spectrum different from those of 2,3-dihydroxybenzoic acid and other bacterial catechol siderophores. Furthermore, the siderophore activity of this extraceliular catechol was confirmed by its ability to stimulate energy-dependent uptake of 55Fe(M) as well as to promote the growth of A. baumannii bacterial cells under iron-deficient conditions imposed by 60 ,uM human transferrin. Polyacrylamide gel electrophoresis analysis showed the presence of iron-regulated proteins in both inner and outer membranes of this clinical isolate ofA. baumannii. Some of these membrane proteins may be involved in the recognition and internalization of the iron-siderophore complexes.Acinetobacter baumannii, formerly known asAcinetobacter calcoaceticus subsp. anitratus (15), belongs to a bacterial species that is widely distributed throughout the environment (6). This microorganism can be isolated from the skin (3, 43) and respiratory tract (59) of healthy ambulatory adults as well as from hospital personnel and equipment (36,39,46,67).Lately, numerous outbreaks of nosocomial infections caused by A. baumannii have been reported (7-10, 16, 42, 47, 56, 57, 73), which are of particular concern because of the widespread and increasing antibiotic resistance of the isolated strains (17,30,32,33,40,41,48). Nevertheless, most infections have occurred in patients compromised by either antibiotic therapy, respiratory instrumentation and manipulations, dialysis, or surgery (18,19,39,70). Thus, it was proposed that reduced host defenses and interaction with other bacterial species, rather than the expression of specific bacterial virulence factors (49), are the factors responsible for opportunistic infections caused by Acinetobacter species.Acinetobacter species are able to survive under restricted nutrient conditions, such as those imposed by the host. Iron is one of the essential bacterial nutrients that is tightly controlled by the host, through its chelation by the highaffinity binding glycoproteins transferrin (TF) and lactoferrin (23). Thus, bacteria have developed efficient iron uptake mechanisms that allow them to scavenge iron from these host proteins, either by direct interaction with the ironprotein complexes (34) or by the synthesis an...

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“…Two other amikacininactivating enzymes have been detected in gram-negative bacteria: the 3'-O-phosphotransferase type VI [APH(3')-VI], which is rare in members of the families Enterobacteriaceae and Pseudomonadaceae but is common in Acinetobacter spp. (17), and the 4'-O-nucleotidyltransferase type II [ANT(4')-II], which is extremely rare (30).…”

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Characterization of transposon Tn1528, which confers amikacin resistance by synthesis of aminoglycoside 3'-O-phosphotransferase type VI

Lambert

Gerbaud

Courvalin

1994

Antimicrob Agents Chemother

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Providencia stuartii BM2667, which was isolated from an abdominal abscess, was resistant to amikacin by synthesis of aminoglycoside 3'-O-phosphotransferase type VI. The corresponding gene, aph(3')-VIa, was carried by a 30-kb self-transferable plasmid of incompatibility group IncN. The resistance gene was cloned into pUC18, and the recombinant plasmid, pAT246, was transformed into Escherichia coli DH1 (recA) harboring pOX38Gm. The resulting clones were mixed with E. coli HB101 (recA), and transconjugants were used to transfer pAT246 by plasmid conduction to E. coli K802N (rec+). Analysis of plasmid DNAs from the transconjugants of K802N by agarose gel electrophoresis and Southern hybridization indicated the presence of a transposon, designated Tn1528, in various sites of pOX38Gm. This 5.2-kb composite element consisted of aph(3')-VIa flanked by two direct copies of IS15-delta and transposed at a frequency of 4 x 10(-5). It therefore appears that IS15-delta, an insertion sequence widely spread in gram-negative bacteria, is likely responsible for dissemination to members of the family Enterobacteriaceae of aph(3')-VIa, a gene previously confined to Acinetobacter spp.

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Dissemination of amikacin resistance gene aphA6 in Acinetobacter spp

Cited by 45 publications

References 23 publications

Versatility of Aminoglycosides and Prospects for Their Future

Versatility of Aminoglycosides and Prospects for Their Future

Characterization of a high-affinity iron transport system in Acinetobacter baumannii

Characterization of transposon Tn1528, which confers amikacin resistance by synthesis of aminoglycoside 3'-O-phosphotransferase type VI

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