Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasmids that confer resistance to cadmium (MIC > or = 125 microM), were found in 18 out of 30 independent Staphylococcus lugdunensis strains from clinical specimens. Variants that were cured of their plasmid were cadmium sensitive. Restriction endonuclease sites of a 3.2-kb cadmium-resistance plasmid of S. lugdunensis, designated pLUG10, were similar to those of pOX6, a S. aureus cadmium-resistance plasmid containing the cadB gene. Southern-blot hybridisation was performed with a probe intragenic to cadB. Hybridisation was found with the cadB probe in the cadmium-resistant S. lugdunensis isolates to the 2.9-, 3.2- and 3.7-kb plasmids. These findings suggest that cadmium-resistance in some S. lugdunensis strains is due to a gene sharing homology with the cadB gene of S. aureus.
 ...
PMID:Cadmium-resistance plasmid in Staphylococcus lugdunensis. 146 17

During a 20-month survey of resistance to three aminoglycosides (gentamicin, tobramycin, and amikacin) in Escherichia coli at a university hospital, six tobramycin-, kanamycin-resistant isolates containing a 50 kilobase conjugative R-plasmid which encoded an aminoglycoside phosphotransferase (APH-(3')) were isolated. The APH-(3') conferred resistance to kanamycin (MIC = 100 mg/L) but not to tobramycin (MIC = 20 mg/L). In both the original isolates and transconjugants the six R-plasmids demonstrated an isomeric ladder in the range of 50-112 kb, which was enhanced by exposure of the bacterial cultures to tobramycin. pJFJ2522 is the prototype for this group of plasmids. Bacterial DNA gyrase reversed the isomeric DNA ladder in pJFJ25222 by increasing the supercoiling of the plasmid DNA. Regardless of the level of supercoiling, the plasmids produced indistinguishable restriction endonuclease fragment patterns. The clinical isolates containing these plasmids demonstrated different restriction fragment length polymorphism (RFLP) of their EcoRI digested genomic DNA using E. coli rRNA as a probe. Ladder formation was plasmid specific since other tobramycin R-plasmids did not form a ladder, but it was not host specific. pJFJ25222 formed a ladder in a recA- host and displayed the same restriction pattern in a recA- as in a recA+ environment. In conclusion, pJFJ2522 contains a new tobramycin resistance gene whose mechanism of resistance is not known and whose product probably influences the isomerization of the plasmid.
 ...
PMID:Isomeric DNA ladder formation of a plasmid encoding tobramycin resistance from Escherichia coli. 168 32

Plasmids mediating high-level resistance to mupirocin (MIC greater than 1000 mg/L) in staphylococci from various sources were studied by restriction endonuclease cleavage. Several patterns were obtained but six plasmids isolated from various Staphylococcus aureus and S. epidermidis strains were indistinguishable. The diversity and spread of these plasmids is illustrated.
 ...
PMID:Diversity of staphylococci exhibiting high-level resistance to mupirocin. 197 17

Imipenem sensitive pretherapy isolates (MICs 1-2 mg/l) and the corresponding resistant posttherapy isolates (MICs 16 mg/l) of Pseudomonas aeruginosa from three patients undergoing imipenem treatment were analyzed to establish the resistance mechanism. The identity of pyocin types, serotypes, DNA restriction endonuclease profiles and plasmid profiles strongly suggested isogenicity of pre- and posttherapy isolates. The imipenem resistant posttherapy isolates showed cross-resistance only to another carbapenem, meropenem. There were neither qualitative nor quantitative differences between pre- and posttherapy isolates in beta-lactamase production. Affinity of the penicillin-binding proteins 1A, 1B, 2, 3, 4,4' and 5 for [14C]imipenem was the same in pre- and posttherapy isolates. One-dimensional and two-dimensional gel electrophoresis of outer membrane protein preparations showed diminished expression of an outer membrane protein of about 46.5 and 47.5 kilodaltons, respectively, in the posttherapy isolates. This protein had an apparent isoelectric point of about pH 5.2 in two-dimensional gel electrophoresis. Growth in proteose peptone no. 2 broth did not reduce expression of this outer membrane protein, which spoke against its identity with the outer membrane protein D1. The permeability of the outer membrane for imipenem was reduced in the posttherapy isolates, since addition of 0.5 or 0.25 of the MIC of the permeabilizing agent ethylene-diaminetetraacetate reduced the MICs of imipenem for all isolates from each patient to the same (susceptible) level. The diminished expression of one of the outer membrane proteins might be the reason for this reduced permeability.
 ...
PMID:Mechanism of imipenem resistance acquired by three Pseudomonas aeruginosa strains during imipenem therapy. 212 59

The increase in the incidence of infections due to beta-lactam-resistant coagulase-negative staphylococci has resulted in expanded use of vancomycin for such infections. Despite this, coagulase-negative staphylococci have remained susceptible to vancomycin in recent years. This report describes a strain of Staphylococcus haemolyticus with increased resistance to vancomycin (MIC, 8.0 to 16 micrograms/ml). S. haemolyticus was initially isolated from a patient with acute leukemia and neutropenia in surveillance throat and stool cultures. The microdilution vancomycin MICs for these isolates were 1.0 to 2.0 micrograms/ml. Subsequent S. haemolyticus isolates from the bloodstream and tracheal aspirate occurred in the setting of prolonged empirical vancomycin therapy. MICs for these isolates were 8.0 to 16 micrograms/ml. Further vancomycin resistance (MIC, 32 micrograms/ml) could be selected for in vitro in all four isolates. Restriction endonuclease analysis of plasmid DNA indicated that the isolates were very closely related and likely to be of the same strain. We conclude that colonization with a vancomycin-susceptible strain of S. haemolyticus was subsequently linked to a nosocomial bloodstream infection with an apparently identical strain with intermediate levels of vancomycin resistance. Prolonged empirical vancomycin therapy was temporally associated with this episode.
 ...
PMID:Vancomycin resistance in Staphylococcus haemolyticus causing colonization and bloodstream infection. 222 88

The clinical findings relating to 11 patients in Hong Kong (HK) and to 43 patients described elsewhere, all with Streptococcus zooepidemicus septicaemia, are reviewed. There was a particular association with cardiovascular disease (27%) with seven cases of endocarditis, three of abdominal aortic aneurysm and two of deep venous thrombosis. Associations not previously reported included two cases of pharyngitis and two patients with persistent post-operative fever. The overall mortality was 22%. Both human and porcine strains of S. zooepidemicus from HK did not hydrolyse aesculin in contrast to the aesculin-positive biotypes reported previously. HK strains also had very mucoid colonies and capsules of hyaluronic acid were seen in electron micrographs. Samples of chromosomal DNA, extracted by means of HindIII restriction endonuclease, of strains from human beings and pigs were identical. The MIC of penicillin for all strains was less than or equal to 0.03 mg/l but the MBC for all was greater than 32 mg/l. Penicillin alone is generally sufficient for cure but combination with an aminoglycoside may be indicated in seriously ill patients. In our locality, pigs were incriminated as a possible source of human infection whereas consumption of contaminated dairy products is important elsewhere.
 ...
PMID:Streptococcus zooepidemicus (Lancefield group C) septicaemia in Hong Kong. 227 71

A small plasmid of 4.4 kb encoding resistance to streptomycin (Smr) was detected in a multiresistant Staphylococcus hyicus culture from a piglet with exudative epidermitis. The plasmid-encoded properties were determined by interspecies protoplast transformation experiments. This plasmid was further characterised by restriction endonuclease analysis and a preliminary restriction map was constructed. The plasmid from S. hyicus that conferred streptomycin resistance was designated as pSAI-1. It showed some structural homology with the streptomycin-chloramphenicol resistance plasmid pSK68 from S. aureus of human origin. The MIC of streptomycin in resistance mediated by pSAI-1 was about 10 times higher than the MICs in resistance mediated by Smr plasmids from human S. aureus strains.
 ...
PMID:A new streptomycin-resistance plasmid from Staphylococcus hyicus and its structural relationship to other staphylococcal resistance plasmids. 237 58

A 42% (70 of 167 isolates) incidence of resistance to 20 micrograms of trimethoprim per ml was found among clinical isolates of coagulase-negative staphylococci from two hospitals. A specific trimethoprim resistance gene probe from a conjugative Staphylococcus aereus plasmid was used to investigate the location of the trimethoprim resistance gene among 29 isolates. In 14 trimethoprim-resistant isolates, the probe hybridized with only chromosomal DNA, in 9 it hybridized with only plasmid DNA, and in 1 isolate both plasmid and chromosomal sequences showed hybridization. In five isolates there was no hybridization of the probe with either chromosomal or plasmid DNA. Four of these five nonhybridizing isolates were Staphylococcus haemolyticus. In contrast, all 22 Staphylococcus epidermidis isolates tested hybridized with the probe. The presence of the trimethoprim resistance gene in a chromosomal location was correlated with a lower MIC (median, 80 micrograms/ml) than when it was plasmid encoded (median, 1,250 micrograms/ml). Restriction endonuclease mapping as well as DNA hybridization of cloned plasmid and chromosomal DNA showed that there were 2.7 kilobases of common DNA in the two loci. This included the 500 base pairs of DNA mediating trimethoprim resistance and a total of 2.2 kilobases of 3'- and 5'-flanking sequences. The presence of the same gene and flanking sequences in chromosomal and plasmid locations suggests that the trimethoprim resistance determinant is translocated among different genetic loci.
 ...
PMID:Molecular epidemiology of trimethoprim resistance among coagulase-negative staphylococci. 343 15

A total of seven Staphylococcus intermedius cultures isolated from cases of canine pyoderma were investigated for the genetic basis of chloramphenicol resistance (Cmr). All of these S. intermedius isolates mediated Cmr via the expression of the Cm-inactivating enzyme chloramphenicol acetyltransferase (CAT); the respective cat genes were found to be located on small multicopy plasmids of 3.1 to 4.1 kb in four of the seven cultures. The four Cmr plasmids, designated pSCS20-23, differed upon restriction endonuclease mapping. Hybridization experiments identified all of them to belong to the pC221-family of staphylococcal Cmr plasmids. The expression of all four plasmid-encoded cat genes was inducible with chloramphenicol. The remaining three S. intermedius isolates also harboured an inducible cat gene of the pC221-type which, however, was found to be located in the chromosomal DNA. These differences in the subcellular localisation and consequently in the number of cat gene copies per S. intermedius cell had no influence on the MIC values of Cm exhibited by the respective S. intermedius isolates.
 ...
PMID:Chloramphenicol resistance in Staphylococcus intermedius from a single veterinary centre: evidence for plasmid and chromosomal location of the resistance genes. 774 Jul 54

Ninety-two and 33 methicillin-resistant Staphylococcus aureus (MRSA) strains were isolated in Japan and China respectively. They were categorised as ofloxacin-susceptible (MIC < 12.5 mg/L), moderately (MIC 12.5-25 mg/L) or highly (MIC > or = 50 mg/L) ofloxacin-resistant. 4-Quinolone concentrations required to inhibit purified DNA gyrase from the moderately and highly quinolone-resistant MRSA were at least 20 times higher than those required to inhibit the equivalent enzyme from quinolone-susceptible strains. Reconstitution assays demonstrated that the 4-quinolone-resistant MRSA had a mutation in subunit A of DNA gyrase. A portion of the gyrA gene from amino acids codons 40-115 was sequenced. Four moderately resistant and seven highly resistant MRSA contained a Ser-->Leu substitution at amino acid 84; one moderately and one highly resistant MRSA and one moderately resistant methicillin-susceptible S. aureus (MSSA) strain contained a Glu-->Lys substitution at amino acid 88. Eight MRSA, including one quinolone-susceptible strain and one MSSA contained a silent mutation at amino acid 86. Uptake of ofloxacin in moderately resistant strains was almost the same in the presence or absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), whereas in highly resistant strains, uptake increased when CCCP was added. Restriction fragment length analysis of the norA gene with the restriction endonuclease SfcI showed a mutation of nucleotide position 1085 in all MRSA strains tested except for one highly quinolone-resistant strain. Thus the mechanisms of 4-quinolone-resistance in these MRSA isolates involved alterations in both DNA gyrase and antimicrobial uptake and efflux.
 ...
PMID:Mechanisms of 4-quinolone resistance in quinolone-resistant and methicillin-resistant Staphylococcus aureus isolates from Japan and China. 788 4


1 2 3 Next >>