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Biomedical subjects

S A Lerner

Publications and source records attributed to S A Lerner.

83 records · Page 5Linked to original sources
PubMed1975

Plasmid deoxyribonucleic acid in clinical isolates of Neisseria gonorrhoeae.

Two different sizes of circular covalently closed deoxyribonucleic acid plasmids have been identified in four independent clinical isolates of Neisseria gonorrhoeae. All four strains contained a small plasmid with a molecular weight of 2.8 X 10-6 and two of the four stains also contained a large plasmid with a molecular weight of 24.5 X 10-6. The avirulent derivative of each of these four strains had the same plasmid complement as its virulent parent. There was no correlation between the presence of these plasmids and antibiotic resistance, piliation, and colony type associated with virulence, or ability to grow without seven specific amino acid supplements.

Amino Acids↗
PubMed1967

Replacement of a phosphoenolpyruvate-dependent phosphotransferase by a nicotinamide adenine dinucleotide-linked dehydrogenase for the utilization of mannitol.

Mannitol is dissimilated by Aerobacter aerogenes via an inducible pathway initiated by a phosphotransferase system dependent upon phosphoenolpyruvate as the phosphoryl donor. A mutational block in this pathway can be suppressed either at the phenotypic level by induction of d-arabitol dehydrogenase, an enzyme fortuitously capable of converting mannitol to fructose, or genotypically by a constitutive mutation in the d-arabitol system.

Enterobacter↗
PubMedDate not supplied

Resistance to imipenem in Pseudomonas aeruginosa: clinical experience and biochemical mechanisms.

Emergence of resistance to imipenem during therapy for Pseudomonas aeruginosa infections is common and may result in treatment failure. Resistance emerges most often during therapy for lower respiratory tract infections. There are several unique features of this resistance to imipenem. First, cross-resistance to other beta-lactam agents is not observed. Second, the mechanism of resistance in most of the isolates studied to date appears to be related to a selective permeability barrier across the bacterial outer membrane, usually associated with discrete alterations in the electrophoretic profiles of outer membrane proteins. These data suggest that imipenem may traverse the outer membrane of P. aeruginosa via a specific porin protein that is not critical for penetration of other beta-lactam antibiotics.

Drug Resistance, Microbial↗
PubMedDate not supplied

Effect of highly potent antipseudomonal beta-lactam agents alone and in combination with aminoglycosides against Pseudomonas aeruginosa.

The activities of ticarcillin, cefsulodin, ceftazidime, aztreonam, and imipenem, formerly known as N-formimidoyl thienamycin, were evaluated alone and in combination with aminoglycosides against 56 clinical isolates of Pseudomonas aeruginosa, which were characterized by aminoglycoside susceptibility and content of aminoglycoside-modifying enzymatic activities. All beta-lactam agents were highly active against aminoglycoside-susceptible isolates, and with few exceptions the aminoglycoside-resistant isolates were susceptible to all of the beta-lactam agents except ticarcillin. Combinations of the beta-lactam agents with aminoglycosides frequently acted synergistically, but the effect of different beta-lactam agents in combination with an aminoglycoside against individual strains was unpredictable. The presence or absence of an aminoglycoside-modifying enzymatic activity had no observed effect on synergism with tobramycin. Killing-curve experiments with strains in the presence of concentrations of a beta-lactam and an aminoglycoside that were not bactericidal alone (one-fourth the minimal bactericidal concentration) showed synergistic bactericidal action against four strains that were tested. The results demonstrate the great activity of these newer antipseudomonal beta-lactam agents and their potential for synergism with aminoglycosides.

Aminoglycosides↗
PubMedDate not supplied

Suggestions for monitoring patients during treatment with aminoglycoside antibiotics.

Guidelines are suggested for the surveillance and prevention of ototoxicity in adults, based on experience and a compilation of opinions from otolaryngologists and infectious disease specialists. The influence of dosage and renal function on serum levels and their relevance to ototoxicity are discussed. Indications for testing of inner ear function are considered.

Amikacin↗
PubMedDate not supplied

Aminoglycoside antibiotics in the treatment of otologic infections.

Aminoglycoside antibiotics can be used successfully in the treatment of otologic infections caused by gram-negative bacteria. They can be particularly valuable, sometimes in combination with a beta-lactam antibiotic such as carbenicillin, in malignant external otitis, acute middle ear infections caused by gram-negative organisms, and central nervous system complications of cholesteatomas. On the basis of susceptibility tests and of the pharmacology of these drugs, we administer appropriate therapeutic doses of one of the following antibiotics: kanamycin, gentamicin, tobramycin, or amikacin. All of these drugs may be ototoxic and nephrotoxic.

Aminoglycosides↗
PubMedDate not supplied

Ganglion cell counts in the cochleae of patients with normal audiograms.

Spiral ganglion cells were counted in the right cochleae of 16 patients with normal audiograms and without a history of hearing deficit or other auditory symptoms. Total counts ranged from 29 802 to 38 352, with a mean of 33 623. There was no relationship between total counts and patient age or between total counts and length of either the cochlea or the spiral ganglion.

Adolescent↗