Prominent publications by Morton N Swartz

KOL Index score: 11790

Novobiocin, coumermycin A1, and clorobiocin, structurally related compounds that antagonize the B subunit of the essential bacterial enzyme DNA gyrase, were compared with 18 of their analogs for the inhibition of Escherichia coli DNA gyrase supertwisting activity in vitro and of bacterial multiplication. This family of compounds has a 4-hydroxy-8-methylcoumarin core substituted in the 7 and 3 positions. Important for enzyme inhibition in vitro is a 7 ether linkage to a 3'-substituted ...

Known for Dna Gyrase |  Escherichia Coli |  Novobiocin Coumermycin |  Bacterial Growth |  3 Position
KOL Index score: 10876

BACKGROUND AND METHODS: To characterize acute bacterial meningitis in adults, we reviewed the charts of all persons 16 years of age or older in whom acute bacterial meningitis was diagnosed at Massachusetts General Hospital from 1962 through 1988. We included patients who were admitted after initial treatment at other hospitals.

RESULTS: During the 27-year period, 445 adults were treated for 493 episodes of acute bacterial meningitis, of which 197 (40 percent) were nosocomial. ...

Known for Acute Bacterial Meningitis |  Community Acquired |  Bacterial Infections |  Haemophilus Influenzae |  Common Pathogens
KOL Index score: 9903

A strain of Salmonella typhimurium appeared sequentially in three patients in a burn unit, and epidemiological study suggested the occurrence of person-to-person spread. This organism was responsible for both colonisation and invasive infection in these patients whose burn surfaces were receiving topical treatment with 0.5% silver nitrate (AgNO3) solution. The antibiotic and metal ionsusceptibility pattern of this strain of S. typhimurium was unique and disturbing: resistant to silver ...

Known for Salmonella Typhimurium |  Silver Nitrate |  Burn Unit |  Resistance Ampicillin |  Escherichia Coli
KOL Index score: 9218

Two genetic loci selected for norfloxacin (nfxB) and ciprofloxacin (cfxB) resistance were characterized. Both mutations have previously been shown to confer pleiotropic resistance to quinolones, chloramphenicol, and tetracycline and to decrease expression of porin outer-membrane protein OmpF. nfxB was shown to map at about 19 min and thus to be genetically distinct from ompF (21 min), and cfxB was shown to be very closely linked to marA (34 min). cfxB was dominant over cfxB+ in ...

Known for Quinolone Resistance |  Escherichia Coli |  Norfloxacin Accumulation |  Outer Membrane |  Intact Cells
KOL Index score: 9050

Seventy-eight patients with genitourinary tuberculosis were evaluated during a 12 year period. Active tuberculosis was confined to the genitourinary tract in all but 10 patients. Aside from five cases of miliary tuberculosis, most genitourinary infections developed from the breakdown of granulomes acquired earlier during transient dissemination from a primary pulmonary infection. Patients with genitourinary tuberculosis exhibited features of local organ dysfunction rather than systemic ...

Known for Genitourinary Tuberculosis |  Cent Patients |  Female Genital |  Weight Loss |  Systemic Symptoms
KOL Index score: 8385

In 38 cases of prosthetic valve endocarditis, 19 were early cases (onset ≦ 60 days after insertion of prosthesis) and 19, late cases (onset ≧ 60 days). Nine late cases had onsets 12 to 53 months after surgery. The sources or predisposing factors in late cases included dental disease or manipulation; genitourinary tract procedures; and skin, urinary, or wound infections. In contrast, most early cases were secondary to complications of operation. Streptococci were the most common ...

Known for Prosthetic Valve |  Late Endocarditis |  Early Cases |  Common Organisms |  Lower Mortality
KOL Index score: 8083

In Escherichia coli the frequency of spontaneous single-step mutation to high levels of resistance to the newer 4-quinolone agent norfloxacin was confirmed to be over 300-fold lower than that to the older agent nalidixic acid. Serial passage on incremental concentrations of drug was necessary to produce mutants highly resistant to norfloxacin. Genetic analysis of one such highly resistant strain identified two mutations conferring drug resistance. One mutation, nfxA, mapped around 48 min ...

Known for Norfloxacin Resistance |  Escherichia Coli |  Genes Genes |  Dna Gyrase Subunit |  Bacterial Mutation
KOL Index score: 7679

Inhibitors of the enzyme bacterial topoisomerase II (DNA gyrase) were evaluated for activity against Trypanosoma cruzi (Brazil strain), based on the theoretical need for a topoisomerase II in the replication of the kinetoplast DNA network. Novobiocin (500 micrograms/ml) antagonized amastigotes of T. cruzi growing in a cell-free medium at 37 degrees C, as manifested by inhibition of multiplication, abnormal morphology of Giemsa-stained organisms, and delayed or absent growth of cells upon ...

Known for Trypanosoma Cruzi |  Cellfree Medium |  Novobiocin Antagonism |  Amastigotes Growing |  Dna Gyrase
KOL Index score: 7457

Quinolone antimicrobial agents rapidly kill bacteria by largely unknown mechanisms. To study this phenomenon, a strain of Escherichia coli inhibited but inefficiently killed by (i.e., partially tolerant to) norfloxacin was isolated and characterized. E. coli KL16 (norfloxacin MIC, 0.10 microgram/ml; MBC, 0.20 microgram/ml) was mutagenized with nitrosoguanidine and cyclically exposed to 3 micrograms of norfloxacin per ml. After five cycles, a bacterial strain (DS1) which was killed ...

Known for Escherichia Coli |  Norfloxacin Ds1 |  Dna Gyrase |  Unknown Mechanisms |  Microbial Sensitivity
KOL Index score: 7455

Norfloxacin, ofloxacin, and other new quinolones, which are antagonists of the enzyme DNA gyrase, rapidly kill bacteria by largely unknown mechanisms. Earlier, we isolated, after mutagenesis, Escherichia coli DS1, which exhibited reduced killing by quinolones. We evaluated the killing of DS1 and several other strains by quinolones and beta-lactams. In time-killing studies with norfloxacin, DS1 was killed 1 to 2 log10 units compared to 4 to 5 log10 units for the wild-type parent strain ...

Known for Escherichia Coli |  New Quinolones |  Antimicrobial Agents |  Beta Lactams |  Killing Ampicillin
KOL Index score: 6726

Clinical isolates of enterococci (Streptococcus faecalis) with high-level resistance to both streptomycin and kanamycin (minimal inhibitory concentration >2,000 mug/ml), and resistant to synergism with penicillin and streptomycin or kanamycin were examined for aminoglycoside-inactivating enzymes. All of the 10 strains studied had streptomycin adenylyltransferase and neomycin phosphotransferase activities; the latter enzyme phosphorylated amikacin as well as its normal substrates, such as ...

Known for Clinical Isolates |  Streptomycin Kanamycin |  Aminoglycoside Resistance |  Antibiotic Synergism |  Streptococcus Faecalis
KOL Index score: 6662

The ability of novobiocin to eliminate (cure) the wild-type plasmid pMG110 from Escherichia coli has been compared with that of other inhibitors of the gyrase B subunit and of the gyrase A subunit. Novobiocin eliminated pMG110 , producing over 99% plasmid loss at concentrations two- to eightfold below the MIC for bacterial growth. Structurally related compounds ( clorobiocin , coumermycin A1, isobutyryl novenamine , and decarbamyl novobiocin) varied in their ability to eliminate pMG110 . ...

Known for Escherichia Coli |  Dna Gyrase |  Nalidixic Acid |  Bacterial Growth |  Novobiocin Plasmids
KOL Index score: 6474

Mating experiments have shown that high-level resistance (minimal inhibitory concentration greater than 2,000 microgram/ml) to streptomycin and kanamycin, and resistance to penicillin-streptomycin and penicillin-kanamycin synergism are transferable by conjugation from resistant clinical isolates of enterococci to a sensitive recipient strain. Cesium chloride-ethidium bromide ultracentrifugation revealed a satellite (plasmid) band in resistant clinical isolates and the transconjugant ...

Known for Antibiotic Synergism |  Streptomycin Kanamycin |  Highlevel Resistance |  Genetic Transformation |  Clinical Isolates


Morton N Swartz: Influence Statistics

Sample of concepts for which Morton N Swartz is among the top experts in the world.
Concept World rank
rapidly fatal sepsis #1
mimicking bacterial #1
plasmids exposure #1
antagonism cruzi #1
bacillus bronchiseptica #1
cytodiagnosis escherichia #1
reactions mimicking #1
meningeal reactions #1
sensitive recipient #1
amastigotes novobiocin #1
novobiocin 14 plasmids #1
thermolabile gyrase subunit #1
— general #1
cells antagonism #1
unusual meningeal #1
dna gyrase kinetics #1
amastigotes growing #1
dirofilaria ursi #1
gyrase antagonism #1
“nonsignificant” bacteremia #1
— meningitis #1
parasite ultrastructure incorporation #1
therapeutic considerations #1
cruzi amastigotes novobiocin #1
plasmid pmg110 #1
paramount combination #1
selected aspects #1
diagnosis genitourinary tuberculosis #1
ventriculoatriostomy #1
493 episodes #1
bordetella bronchiseptica maltophilia #1
special problems #1
patients communityacquired meningitis #1
bacterial species novobiocin #1
current bacteriologic technics #1
eliminated cured #1
patients genitourinary tuberculosis #1
cerebrospinalfluid examination #1
cells semipermissive temperatures #1
“incidental” organisms #1
plasmids pbr322 pmg110 #1

Key People For Bacterial Meningitis

Top KOLs in the world
Diederik van de Beek
bacterial meningitis brain abscess acute stroke
William Michael SCHELD
bacterial meningitis brain abscess severe sepsis
Allan R Tunkel
bacterial meningitis food insecurity central nervous
George H McCracken
bacterial meningitis newborn infant haemophilus influenzae
Jan de Gans
bacterial meningitis aids dementia complex cerebrospinal fluid
Sheldon L Kaplan
staphylococcus aureus united states bacterial meningitis

Morton N Swartz:Expert Impact

Concepts for whichMorton N Swartzhas direct influence:Bacterial meningitis,  Dna gyrase,  Escherichia coli,  Septic thrombosis,  Trypanosoma cruzi,  Reduced killing,  Special problems,  Therapeutic considerations.

Morton N Swartz:KOL impact

Concepts related to the work of other authors for whichfor which Morton N Swartz has influence:Bacterial meningitis,  Pasteurella multocida,  Epidural abscess,  Staphylococcus aureus,  Escherichia coli,  Chronic osteomyelitis,  Cerebrospinal fluid.



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Department of Medicine, Massachusetts General Hospital, Boston, USA. | Division of Infectious Disease and the Jackson Firm, Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA. | Massachusetts General Hos

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