Chromosomally mediated beta-lactamase production and gentamicin resistance in Enterococcus faecalis

Rice, Louis B.; Eliopoulos, George M.; Wennersten, Christine; Goldmann, Donald A.; Jacoby, George A.; Moellering, Robert C.

doi:10.1128/aac.35.2.272

Cited by 63 publications

(49 citation statements)

References 21 publications

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“…Resistance to antibiotics among E. faecalis is frequent; e.g. resistance to Gm has already been reported by Rice et al (1991). An important finding in our study was no Van resistant isolates; several reports exist concerning Van resistant enterococci from animals (Woo Kyung Jung et al 2007).…”

Section: Discussionsupporting

confidence: 49%

Characteristic and susceptibility to enterocins of enterococci in pheasants possessing virulence factor genes

Kandričáková¹,

Lauková²,

Strompfová³

2015

Polish Journal of Veterinary Sciences

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With an increasing number of pheasants as gamebirds being reared each year, these species are becoming a more prominent part of the workload of many veterinary practices. Only limited information can be found concerning the microflora of common pheasants. A significant part of the obligate microflora consists of lactic acid bacteria, including enterococci. In this study, faeces were sampled from 60 pheasants aged 16-17 weeks. Enterococcal counts reached 5.48±1.9 (log10) CFU/g. Strains (17) were taxonomically classified to the genus Enterococcus using the Maldi-Tof identification system; they were allotted to the species E. hirae (58.8%), E. faecium (23.5%) and E. faecalis (17.7%) by highly probable species identification or by secure genus identification/probable species identication. Species allocation was also confirmed using conventional biochemical tests. Most strains formed β-hemolysis. Gelatinase active phenotype was found in three E. faecalis strains. Enterococci were β-glucuronidase negative, mostly trypsin negative with slight or moderate production of α-chymotrypsin. EH52b and EF42 strains possessed the highest potential for pathogenicity. Average value of lactic acid was 1.78±0.33 mmo/L. Most strains were tetracycline resistant (82.4%). Polyresistant E. faecalis strains with positive gelatinase phenotype and possessing virulence factor genes confirmed using PCR (gelE, efaAfs, ccf cob, cpd) were sensitive to enterocins (activity 1600-25 600 AU/mL).

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Section: Discussionsupporting

confidence: 49%

Characteristic and susceptibility to enterocins of enterococci in pheasants possessing virulence factor genes

Kandričáková¹,

Lauková²,

Strompfová³

2015

Polish Journal of Veterinary Sciences

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“…This stability could be probably supported by the chromosomal encoding of LA as has been found e.g. for rifampicin resistance in enterococcci (Lauková and Kuncová 1991;Rice et al 1991). Detection of the structural enterocin genes by PCR is a method that was not available years ago.…”

Section: Resultsmentioning

confidence: 99%

Enterococci Isolated from Japanese Quails Exposed to Microgravity Conditions and Stability of their Properties

Lauková

Michlovičová

2009

Acta Vet. Brno

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Enterococci isolated from the crop and caecum of Japanese quails exposed to 7 day conditions of microgravity were re-vitalized after their dry-freezing long storage. Originally, the strains were isolated from Japanese quails after their landing from flight onboard the orbital station Mir during the experiment in August 1990. Because taxonomy as well as the studies concerning the bacteriocins, especially those produced by enterococci, have been continually developed for years, the aim of this study was to confirm species identification, stability of the properties of enterococci as well as to test new properties after their long storage. Genotyping allotted the strains to the species E. faecium. Lactic acid production was detected in similar amounts in the strains before and after their long-storage in dry-frozen form. The strains were vancomycinsensitive and kanamycin-resistant before as well as after their long-time storage. Variability in sensitivity to different antibiotics was found among the strains tested even before and after longtime storage. Each of the strains possessed at least one structural enterocin gene. The structural genes for enterocin A, P, B, L50B were detected in E. faecium EP7. E. faecium EP2, EEP4 have the genes for ent A, B, L50B. The gene for ent P was detected only in the strain EP7. The most often detected was ent A gene followed by ent genes B, L50B. All strains inhibited growth of at least 4 out of 15 indicators. The stability of the enterococcal properties determined before as well as after their dry-freezing was not influenced during their long-term storage; moreover, new properties were determined. Enterococci, storage, enterocin gene, properties, stabilityJapanese quails represent suitable animal laboratory model for several reasons: their small size, low husbandry costs, short generation interval and adaptability to a wide range of husbandry conditions. Therefore, in past they were an object of the scientific space research programme (Boďa 1979) called Interkozmos that was finished in 1990s. In this programme many research issues were investigated and solved; e.g. the effect of microgravity on endocrine functions and adaptation processes (Juráni et al. 1988), embryonic development (Boďa et al. 1992) and/or morphological changes in the small intestine under space-flight conditions (Cigánková et al. 2000). Moreover, in the framework of the Interkozmos programme-Incubator 2, firstly also microflora of Japanese quails exposed to microgravity conditions was analysed in comparison to conventional Japanese quails with an impact on lactic acid bacteria such as lactobacilli, enterococci and staphylococci (Lauková et al. , 1993a(Lauková et al. , 1995. The most studied were enterococci that were also found to produce antimicrobial substances -bacteriocins (Lauková et al. 1993bc). The studied isolates were dry-frozen and stored for a long period for other tests. Because taxonomy as well as the studies concerning bacteriocins, especially those produced by enterococci, were continuall...

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“…Because Tn916 and Tn925 are so closely related structurally, it has been proposed that these apparent differences may reflect a difference in the efficiency with which the transposons induce pore formation between mating cells (11). The strain from which TnS381 was derived (CH19) has been shown to transfer a number of chromosomal antimicrobial-resistance determinants in the absence of detectable plasmid DNA (22). These multiple-resistance transfers are always accompanied by the transfer of the tetM determinant, raising the possibility of a role for TnS381 in the transfer of a range of chromosomal antimicrobial-resistance genes.…”

Section: Resultsmentioning

confidence: 99%

“…yet transferable in various combinations to an enterococcal recipient (22). The present paper further elucidates the mechanism of transfer of tetracycline resistance from two of these strains, implicating two 19-kb conjugative transposons (TnS381 and TnS383), one of which has been identified as a closed circle independent of the host chromosome.…”

mentioning

confidence: 92%

Tn5381, a conjugative transposon identifiable as a circular form in Enterococcus faecalis

1992

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We have identified two 19-kb conjugative transposons (Tn5381 and Tn5383) in separate strains of multiply resistant Enterococcusfaecalis. These transposons confer resistance to tetracycline and minocycline via a tetM gene, are capable of both chromosomal and plasmid integration in a Rec-environment, and transfer between strains in the absence of detectable plasmid DNA at frequencies ranging from < 1 x 10-9 to 2 x 10'S per donor CFU, depending on the donor strain and the growth conditions. Hybridization studies indicate that these transposons are closely related to Tn916. We have identified bands of ca. 19 kb on agarose gel separations of alkaline lysis preparations from E. faecalis strains containing chromosomal copies of Tn5381, which we have confirmed to be a circularized form of this transposon. This phenomenon has previously been observed only when Tn916 has been cloned in Escherichia coli. Overnight growth of donor strains in the presence of subinhibitory concentrations of tetracycline results in an approximately 10-fold increase in transfer frequency of Tn5381 into enterococcal recipients and an increase in the amount of the circular form of Tn5381 as detectable by hybridization. These results suggest that Tn5381 is a Tn916-related conjugative transposon for which the appearance of a circular form and the conjugative-transfer frequency are regulated by a mechanism(s) affected by the presence of tetracycline in the growth medium.Conjugative transposons have been implicated in the dissemination of antimicrobial resistance among numerous gram-positive genera (4, 6). Tn916, a 16.4-kb conjugative transposon encoding resistance to tetracycline and minocycline, was first described for a strain of Enterococcusfaecalis in 1980 (12). Since that time, numerous similar elements have been described elsewhere (1,4,9,14). Common to all of these elements are a preference for integration into the bacterial chromosome, the ability to transfer between strains in the absence of detectable plasmid DNA, and the ability to alter the hemolytic properties of hemolysin-and bacteriocinproducing plasmids. With few exceptions (1, 21), conjugative transposons have encoded a tetM tetracycline and minocycline resistance determinant. In most cases, these elements have been shown to have a broad host range within gram-positive genera.On the basis of the apparent precise excision and insertion without target duplication of Tn916, a novel mechanism of transposition involving a nonreplicative circular intermediate was proposed elsewhere (13). Evidence to support the hypothesis of this mechanism includes the identification of a supercoiled form of Tn916 within an Escherichia coli strain which had been transformed with a Tn916-containing chimeric cosmid. This supercoiled molecule was able to transform Bacillus subtilis and subsequently transfer tetracycline resistance to Streptococcus pyogenes in the absence of detectable plasmid DNA (24). Although it is presumed that circular intermediates of conjugative transposons exist within the gram-positi...

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Chromosomally mediated beta-lactamase production and gentamicin resistance in Enterococcus faecalis

Cited by 63 publications

References 21 publications

Characteristic and susceptibility to enterocins of enterococci in pheasants possessing virulence factor genes

Characteristic and susceptibility to enterocins of enterococci in pheasants possessing virulence factor genes

Enterococci Isolated from Japanese Quails Exposed to Microgravity Conditions and Stability of their Properties

Tn5381, a conjugative transposon identifiable as a circular form in Enterococcus faecalis

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