PubMed Health⌕ Search

Biomedical subjects

A Casetta

Publications and source records attributed to A Casetta.

9 recordsLinked to original sources
PubMed2003

Emergence of nosocomial Pseudomonas aeruginosa colonization/infection in pregnant women with preterm premature rupture of membranes and in their neonates.

The epidemiology, risk factors, maternal and neonatal outcomes of nosocomial Pseudomonas aeruginosa acquisition in preterm premature rupture of membranes were analysed. Of 63 women receiving antibiotic prophylaxis with co-amoxiclav, 11 acquired P. aeruginosa vaginal carriage with a median delay of 15 days (6-42) i.e. an incidence of 8.94 per 1000 days of expectant management. Five neonates born to 11 positive mothers were colonized or infected, three of whom died of fulminant sepsis. The duration of antibiotic treatment and multiple pregnancy were identified as independent risk factors. The epidemiological investigation revealed a vertical transmission between mothers and neonates, and suggested selective pressure of antibiotic treatment.

Adult↗
PubMed2000

Streptococcus salivarius acute meningitis with latent petromastoiditis.

A 48-y-old woman, with a previous history of neurosurgical intervention for a trigeminal neurinoma, presented with acute meningitis due to Streptococcus salivarius. There were significant changes in the petrous region, as revealed by MRI, leading to the diagnosis of associated latent subacute mastoiditis.

Acute Disease↗
PubMed2000

Biochemical-genetic characterization and distribution of OXA-22, a chromosomal and inducible class D beta-lactamase from Ralstonia (Pseudomonas) pickettii.

From genomic DNA of Ralstonia pickettii isolate PIC-1, a beta-lactamase gene was cloned that encodes the oxacillinase OXA-22. It differs from known oxacillinases, being most closely related to OXA-9 (38% amino acid identity). The hydrolytic spectrum of OXA-22 is limited mostly to benzylpenicillin, cloxacillin, and restricted-spectrum cephalosporins. OXA-22-like genes were identified as single chromosomal copies in five other R. pickettii clinical isolates. The expression of OXA-22-like beta-lactamases was inducible in R. pickettii.

Amino Acid Sequence↗
PubMed1998

Diversity of structures carrying the high-level gentamicin resistance gene (aac6-aph2) in Enterococcus faecalis strains isolated in France.

Of 24 high-level gentamicin-resistant clinical isolates of Enterococcus faecalis, 20 carried gentamicin resistance (Gmr) plasmids. The plasmids ranged from 65.0 to 80.0 kb in size. Three of these plasmids were nonconjugative, and 17 transferred by conjugation to an E. faecalis recipient at low frequency (10(-5) to 10(-6) transconjugants per donor). The remaining four strains had a nonconjugative chromosomal Gmr determinant. On the basis of restriction enzyme and DNA-DNA hybridization profiles, Tn4001-like alpha elements were located on the chromosome and three types of Tn4001-truncated structures, I, II, and III, were found to be carried by the Gmr plasmids. Structure I lacked IS256 in the right-hand flanking extremity of Tn4001. Structure II was the same as structure I except that it also had a partial deletion of IS256 in the left-hand flanking extremity of Tn4001. Structure III lacked both the right- and left-hand flanking extremities of Tn4001. One of the wild-type strains carried the Gmr determinant both on the chromosome, as a Tn4001-like alpha element, and on a conjugative plasmid, as a Tn4001-truncated type I structure.

Chromosome Mapping↗
PubMed1998

Molecular characterization of OXA-20, a novel class D beta-lactamase, and its integron from Pseudomonas aeruginosa.

The Pseudomonas aeruginosa Mus clinical isolate produces OXA-18, a pI 5.5 class D extended-spectrum beta-lactamase totally inhibited by clavulanic acid (L. N. Philippon, T. Naas, A.-T. Bouthors, V. Barakett, and P. Nordmann, Antimicrob. Agents Chemother. 41:2188-2195, 1997). A second beta-lactamase was cloned, and the recombinant Escherichia coli clone pPL10 expressed a pI 7.4 beta-lactamase which conferred high levels of amoxicillin and ticarcillin resistance and which was partially inhibited by clavulanic acid. The 2.5-kb insert from pPL10 was sequenced, and a 266-amino-acid protein (OXA-20) was deduced; this protein has low amino acid identity with most of the class D beta-lactamases except OXA-2, OXA-15, and OXA-3 (75% amino acid identity with each). OXA-20 is a restricted-spectrum oxacillinase and is unusually inhibited by clavulanic acid. OXA-20 is a peculiar beta-lactamase because its translation initiates with a TTG (leucine) codon, which is rarely used as a translational origin in bacteria. Exploration of the genetic environment of oxa20 revealed the presence of the following integron features: (i) a second antibiotic resistance gene, aacA4; (ii) an intI1 gene; and (iii) two 59-base elements, each associated with either oxa20 or aacA4. This integron is peculiar because it lacks the 3' conserved region, and therefore is not a sul1-associated integron like most of them, and because its 3' end is located within tnpR, a gene involved in the transposition of Tn5393, a gram-negative transposon. P. aeruginosa Mus produces two novel and unrelated oxacillinases, OXA-18 and OXA-20, both of which are inhibited by clavulanic acid.

Amino Acid Sequence↗
PubMed1997

[Pancytopenia in acute brucellosis].

Leuconeutropenia is a common manifestation of acute brucellosis, whereas other hematological abnormalities and pancytopenia are uncommon. We report a patient presenting with acute brucellosis and pancytopenia.

Acute Disease↗
PubMed1993

Analysis of pristinamycin-resistant Staphylococcus epidermidis isolates responsible for an outbreak in a Parisian hospital.

In 1990, over a 6-month period, an increase from 1 to 10% in the incidence of pristinamycin resistance among coagulase-negative staphylococci was observed in four intensive care units of a Parisian hospital. Twenty-three such isolates, as well as 25 pristinamycin-susceptible Staphylococcus epidermidis isolates, were collected and typed by analyzing various bacterial constituents. Two structurally related plasmids of 7.3 and 14.3 kb, carrying the gene vga encoding resistance to pristinamycin, were detected in the 23 pristinamycin-resistant coagulase-negative staphylococci which were identified as S. epidermidis. Although related by numerous common characteristics, 20 of these 23 isolates could be divided into two types, A (17 isolates) and B (three isolates). These types were characterized on the basis of their plasmid contents and hybridization patterns obtained when the EcoRI-digested DNA was probed with plasmid pIP1551 containing an internal fragment of the insertion sequence IS256. These findings suggest that the dissemination of type A epidemic strains was, in large part, responsible for the outbreak.

Base Sequence↗
PubMed1991

[Vancomycin in 1991: current status and perspectives].

Vancomycin is a narrow-spectrum glycopeptide antibiotic which is primarily active against Gram-positive organisms. Bacterial resistance develops rarely due to its numerous modes of action. The mode of action of vancomycin involves the inhibition of peptidoglycan synthesis. Vancomycin forms a stoichiometric complex with the peptidoglycan precursor UDP-N-acetylmuramyl pentapeptide by forming hydrogen bonds. In patients with renal insufficiency vancomycin clearance is reduced and elimination half-life prolonged. Vancomycin is the drug of choice in the treatment of methicillin-resistant staphylococcal infections and in the treatment of Gram-positive endocarditis and has been used as alternative therapy in the treatment or prophylaxis of Gram-positive infections in penicillin-allergic patients.

Cell Division↗