bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibitory Effects of Citrates in the Determination of Trace Amounts of Penicillin
Authors: Wood R. T. , Cohen D. M. , Munnelly K. P.
Published: June 2012

In the microbiological assay for the determination of trace amounts of penicillin, it has been shown that sodium citrate and penicillin act synergistically against
Sarcina lutea
. The inhibitory action of citrate appears to involve a sequestering of divalent cations essential to the growth of the organism as shown by minimal inhibitory concentration and agar diffusion studies. The addition of calcium or magnesium to broth or agar at various concentrations overcomes this inhibition, and 0.02 M magnesium was found to be the most effective concentration. On agar supplemented with magnesium chloride, penicillin dose-response curves with and without citrate present were practically superimposable, and larger inhibition zones against a greater amount to total growth resulted in improved assay susceptibility and an interference-free method. Misleading results can be obtained when pharmaceutical products containing citrates are tested by conventional methods for penicillin cross-contamination.
Production of Cephalosporin C by Single and Double Sulfur Auxotrophic Mutants of
Cephalosporium acremonium
Authors: Drew Stephen W. , Demain Arnold L.
Published: June 2012

An early blocked sulfur amino acid auxotroph,
Cephalosporium acremonium
mutant 274-1 (which could be satisfied by methionine or cysteine), utilized organic sulfur compounds for cephalosporin C production in the following order of decreasing effectiveness; methionine > cystathionine > cysteine, despite the fact that cysteine is considered to be the immediate precursor of the antibiotic. When a genetic block was added to mutant 274-1 in the transsulfuration pathway from cysteine to methionine, the double mutant 11-8 (which grows on methonine but not cysteine) failed to produce cephalosporin C from cysteine even though enough methionine was added to support normal growth. Addition of the non-sulfur analogue, norleucine, resulted in antibiotic production from cysteine in the double mutant. These facts support the hypothesis that methionine stimulation of cephalosporin C production is due to a role of methionine other than that of sulfur donation.
Gentamicin Blood Levels: a Guide to Nephrotoxicity
Authors: Dahlgren James G. , Anderson Elizabeth T. , Hewitt William L.
Published: June 2012

Gentamicin blood levels were monitored in 86 patients. Twenty-one patients had valley levels over 2 μg/ml and 36% of these patients developed abnormal serum creatinine or a further rise in creatinine. No patient had a rise in creatinine without a valley level over 2. The peak levels in patients with valleys over 2 were above 10 μg/ml in only one case, whereas four patients had peaks over 10 μg/ml without nephrotoxicity. The mean peak blood levels in patients with a normal creatinine were dose related. An initial dose of 2.0, 1.5, and 1.3 or less mpk (mg/kg) yielded mean peak blood levels of 5.2, 4.7, and 3.7, respectively. To assure an initial peak blood level over 4 μg/ml a loading dose of 2 mpk was required. A rise in peak and valley levels during therapy appeared dose related, being observed in all patients treated with 4.5 mpk daily but not in those receiving 3.0 mpk daily. A radioenzymatic assay was used to validate the standard agar diffusion assay method. The results from the two assays were statistically identical. Valley blood levels of gentamicin may be useful for predicting accumulation of gentamicin which in turn may be correlated with early renal impairment before potentially toxic serum levels of gentamicin develop.
Accuracy of Kirby-Bauer Susceptibility Tests Read at 4, 8, and 12 Hours of Incubation: Comparison with Readings at 18 to 20 Hours
Authors: Kluge Ronica M.
Published: June 2012

Disk diffusion antibiotic susceptibility tests as performed by the hospital diagnostic microbiology laboratory were read at 4, 8, and 12 h of incubation and compared to the traditional 18-h readings. Both the zone size in millimeters and a judgement of susceptible or resistant were recorded by the investigator at each time interval for each drug tested against the various clinical isolates. Considerable variation of zone sizes existed for certain organisms (e.g., staphylococci and
Proteus
) and certain antibiotics (e.g., trimethoprim-sulfamethoxazole) when zone sizes in millimeters were examined. However, 8 to 60% of isolates demonstrated visible growth at 4 h of incubation and could be placed in susceptible or resistant categories with a fair degree of accuracy (74 to 95% agreement with 18-h readings). By 8 h of incubation, 83 to 100% of the cultures showed visible growth and almost all the organisms had accurate readings (89 to 98% agreement). The ability to determine antimicrobial susceptibility patterns early could influence favorably the prognosis in serious infections.
Antibacterial Activity of Nitropyrroles, Nitrothiophenes, and Aminothiophenes In Vitro
Authors: Wang Ching Y. , Chiu Chung W. , Muraoka Keiji , Michie Preston D. , Bryan George T.
Published: June 2012

The antibacterial activities of nitropyrroles, nitrothiophenes, and aminothiophenes were studied. Replacement of the nitro group with an amino group enhanced the activity of the thiophene compounds.
Comparison of Cefoxitin and Cephalothin Therapy of a Mixed
Bacteroides fragilis
and
Fusobacterium necrophorum
Infection in Mice
Authors: Hackman A. S. , Wilkins T. D.
Published: June 2012

Cefoxitin, a β-lactamase-resistant cephalosporin, was found to be more effective than cephalothin against an experimental mixed infection containing
Bacteroides fragilis
and
Fusobacterium necrophorum
.
Third Type of Plasmid Conferring Gentamicin Resistance in
Pseudomonas aeruginosa
Authors: Smith David I. , Lus R. Gomez , Calvo M. C. Rubio , Datta Naomi , Jacob A. E. , Hedges R. W.
Published: June 2012

R1033 is a plasmid of compatibility group P (= P1) transferred from a wild strain of
Pseudomonas aeruginosa
. It confers resistance to gentamicin by gentamicin acetyl-transferase 1 and to kanamycin and neomycin by neomycin phosphotransferase 1.
Plasmid-Determined Epistatic Susceptibility to Kasugamycin
Authors: Danbara Hirofumi , Yoshikawa Masanosuke
Published: June 2012

The effect of two representative plasmids, R100 and F8-gal, on the susceptibility of
Escherichia coli
to kasugamycin was studied. R
+
and F
+
cells were found to be more susceptible to this antibiotic than R
−
and F
−
cells, respectively. Retransfer and curing experiments of these plasmids show that this increased susceptibility of host cells to kasugamycin was conferred by either of the plasmids. At the early stage of growth of R100
+
cells in the presence of kasugamycin, R
−
segregants overgrew the population and then they were replaced by kasugamycin-resistant mutants of the R
+
cells which became the majority cell line of the population. The former phenomenon is assumed to be due to the increased susceptibility of R100
+
cells to kasugamycin, and the latter is probably related to the finding that R100 enhances the spontaneous mutation of host cells to resistance to kasugamycin. The practical and experimental significance of these findings are discussed.
Irreversible Inhibition of Herpes Simplex Virus Replication in BSC-1 Cells by Zinc Ions
Authors: Gordon Yitzhak J. , Asher Yael , Becker Yechiel
Published: June 2012

Zinc sulfate added to the medium of herpes simplex virus-infected BSC-1 cells, at a concentration of 0.1 mM, inhibited the synthesis of infectious virus progeny by 95 to 96%. A concentration of 0.2 mM zinc sulfate inhibited herpes simplex virus synthesis by 99.8% as determined by centrifugation in sucrose gradients and by plaque assay on BSC-1 monolayers. The inhibition of herpes simplex virus replication in BSC-1 cells was found to be irreversible.
Enhancement by Nalidixic Acid of the Thermal Susceptibility of the Ts-7 Mutant of
Escherichia Coli
TAU-Bar
Authors: Nishida Mikio , Mishima Yukio , Kawada Jun , Yielding K. Lemone
Published: June 2012

Nadilidixic acid at 5 × 10
−6
M produced a substantial increase in thermal susceptibility of Ts-7, suggesting either that the thermal and nalidixic acid targets are identical or closely interdependent.
Viral Keratitis-Inhibitory Effect of 9-β-
d
-Arabinofuranosylhypoxanthine 5′-Monophosphate
Authors: Sidwell Robert W. , Allen Lois B. , Huffman John H. , Revankar Ganapathi R. , Robins Roland K. , Tolman Richard L.
Published: June 2012

Topical application of 9-β-
d
-arabinofuranosylhypoxanthine 5′-monophosphate (ara-HxMP) significantly inhibited the development of keratitis induced by types 1 and 2 herpes simplex virus and vaccinia virus in the eyes of rabbits. Parameters for evaluation of efficacy were infectivity (corneal opacity, lesion size, and type), Draize (erythema, conjunctival swelling, and discharge), and reduction in titer of recoverable virus from the eye. When the relative efficacy of the related compounds 9-β-
d
-arabinofuranosyladenine (ara-A), ara-A 5′-monophosphate (ara-AMP), and ara-Hx was determined against type 1 herpes simplex virus in a parallel experiment, the more water-soluble compounds (ara-HxMP, ara-AMP) were the most effective. The relative efficacy of ara-A was also determined against type 2 herpes and vaccinia virus-induced keratitis. Mortality in rabbits due to central nervous system involvement caused by types 1 and 2 herpes simplex virus was inhibited. Ara-HxMP was not discernibly toxic to the eye at concentrations of at least 20%; efficacy was still discernible with a 0.1% solution.
Comparison of In Vitro Susceptibility of
Neisseria gonorrhoeae
to Trimethoprim-Sulfamethoxazole on Three Different Media
Authors: Yoshikawa Thomas T. , Miyamoto Sharon , Guze Lucien B.
Published: June 2012

In vitro susceptibility of 100 clinical isolates of
Neisseria gonorrhoeae
to trimethoprim-sulfamethoxazole (TMP-SMZ combination; 1:19) was determined by the agar dilution technique using three different media under similar conditions. On Oxoid diagnostic sensitivity test, Mueller-Hinton, and GC agar media, the percentage of isolates inhibited by 2.5 μg or less of TMP per ml and 47.5 μg or less of SMZ per ml were 95, 90, and 84%, respectively. TMP-SMZ appeared to be effective in vitro against
N. gonorrhoeae
despite differences in the types of media used.
Synergism of Oxacillin and Gentamicin Against Enterococci
Authors: Marier Robert L. , Joyce Nancy , Andriole Vincent T.
Published: June 2012

Strains of enterococci isolated from 34 patients were studied for susceptibility to oxacillin and gentamicin alone and in combination. The minimal bactericidal concentrations of oxacillin and gentamicin for these strains ranged from 16 to 250 μg/ml (median 32 μg/ml) for oxacillin and 12 to 48 μg/ml (median 24 μg/ml) for gentamicin. The minimal bactericidal concentration of oxacillin for 50% of strains in the presence of 12, 6, 3, and 1.5 μg of gentamicin per ml, respectively, was 2, 8, 16, and 32 μg/ml. The combination of oxacillin and gentamicin at clinically attainable serum levels was synergistically bactericidal against 27/34 (80%) of these strains using strict criteria. This report reconfirms the original observation that antibiotics which affect the synthesis of bacterial cell walls combine synergistically with aminoglycosides against enterococci. This is so even though enterococci are far more resistant to oxacillin than to penicillin or ampicillin. In addition, this report suggests that the combination of oxacillin and gentamicin administered in the usual dosages includes enterococci in its bactericidal spectrum.
Microdilution Technique for Antimicrobial Susceptibility Testing of
Haemophilus influenzae
Authors: Jorgensen James H. , Lee Jean C.
Published: June 2012

A microdilution method incorporating the use of color-defined growth end points was compared with a conventional broth tube dilution procedure for susceptibility testing of
Haemophilus influenzae
with ampicillin and chloramphenicol. The microdilution method allowed rapid performance of dilution susceptibility tests with easily defined end points.
Cefamandole: Antimicrobial Activity In Vitro of a New Cephalosporin
Authors: Meyers Burt R. , Leng Bernard , Hirschman Shalom Z.
Published: June 2012

Cefamandole, a new cephalosporin derivative, was found to have a broad spectrum of activity against a cross-section of both gram-positive and gram-negative bacteria isolated from clinical material. Gram-positive cocci, except for
Streptococcus faecalis
, were very susceptible. Penicillin G-resistant
Staphylococcus aureus
also was susceptible to cefamandole. Minimal bactericidal concentrations for gram-positive cocci approximated the minimal inhibitory concentrations. Strains of
Haemophilus influenzae
were very susceptible to the drug. Most strains of
Escherichia coli, Klebsiella
sp., and
Proteus
sp. were inhibited by low concentrations. Increasing resistance occurred with larger inocula. Strains of
Pseudomonas
sp. were resistant to cefamandole.
Susceptibility of Beta-Hemolytic Streptococci to 65 Antibacterial Agents
Authors: Finland Maxwell , Garner Carol , Wilcox Clare , Sabath Leon D.
Published: June 2012

Tests for susceptibility of 29 group A, 4 group C, and 2 group G strains of beta-hemolytic streptococci to 63 antibiotics and to trimethoprim and sulfamethoxazole, singly and combined in a ratio of 1:16, were carried out in vitro. All strains tested were moderately or highly susceptible to all the antibiotics used except those belonging to the aminoglycoside and polymyxin groups. A few were also resistant to the tetracyclines and to sulfamethoxazole alone. Comparisons with results obtained in previous years indicate that, except for the tetracyclines and sulfonamides, there has been no change in the susceptibility of beta-hemolytic streptococci to the most important and useful antibiotics, particularly penicillin.
Induction of Erythromycin Resistance in
Staphylococcus aureus
by Erythromycin Derivatives
Authors: Pestka Sidney , Vince Robert , LeMahieu Ronald , Weiss Florence , Fern Lucille , Unowsky Joel
Published: June 2012

The ability of 53 erythromycin analogues to induce resistance to erythromycin in
Staphlococcus aureus
was evaluated. Only derivatives with antibacterial activity induced resistance, although some antibacterial compounds did not induce resistance. No derivatives without antibacterial activity but with ability to induce resistance were found.
Interspecies Transformation of Streptomycin Resistance in Oral Streptococci
Authors: Davidson J. R. , Blevins W. T. , Feary T. W.
Published: June 2012

Donor deoxyribonucleic acid extracted from streptomycin-resistant (Str
R
) mutant derivatives of a variety of strains of
Streptococcus mutans, S. salivarius
, and
S. sanguis
was used to transform streptomycin resistance into competent
S. sanguis
strain Challis. Transfer of genetic markers for sorbitol and mannitol fermentation and for extracellular polysaccharide as demonstrated by colonial morphology was not detected in this study. Reciprocal transformation between strain Challis and other oral streptococci could not be demonstrated. Transformation frequencies for Str
R
were relatively efficient among
S. sanguis
strains, with lower but significant frequencies demonstrated with strain Challis and donor deoxyribonucleic acid derived from other oral streptococci.
Inactivation of Lambda Phage Infectivity and Lambda Deoxyribonucleic Acid Transfection by
N
-Methyl-Isatin β-Thiosemicarbazone–Copper Complexes
Authors: Levinson Warren , Helling Robert
Published: June 2012

The infectivity of intact lambda phage and transfection by lambda deoxyribonucleic acid were inactivated by exposure to the copper complexes of
N
-methyl-isatin β-thiosemicarbazone, thiosemicarbazide, and semicarbazide, but not methyl-isatin. No inactivation was observed when these compounds were used in the absence of copper sulfate. This confirms our previous observation that the activity of
N
-methyl-isatin β-thiosemicarbazone is mediated by its thiosemicarbazone moiety and that the presence of copper is required for action. This represents the first time, to our knowledge, that semicarbazide has been found to possess antiviral activity. It is clear that these compounds act directly on deoxyribonucleic acid; whether the compounds also act on proteins has not been determined.
Inhibition of Herpesvirus Deoxyribonucleic Acid and Protein Synthesis by Tilorone Hydrochloride
Authors: Katz Ehud , Margalith Eva , Winer Bela
Published: June 2012

Tilorone hydrochloride at a concentration of 10 μg/ml very efficiently inhibited herpes simplex virus growth in BSC1 cells when the virus is infected at a low multiplicity of infection. The adsorption of the virus was not affected by the drug, and the penetration of the deoxyribonucleic acid of the input virus into the cytoplasm and nuclei proceeded normally when tilorone hydrochloride was present. However, newly synthesized viral deoxyribonucleic acid was not detectable under these conditions, there was a remarkable decrease in the rate of viral polypeptide synthesis, and virus particles were not formed. The inhibition of herpesvirus growth by tilorone hydrochloride was absolutely dependent on the presence of the drug in the cultures. Pretreatment of the cells with the drug did not result in resistance to herpesvirus infection after the removal of the drug.
Spurious Ampicillin Resistance by Testing
Haemophilus influenzae
with Agar Containing Supplement C
Authors: Washington John A. , Snyder Robert J. , Kohner Peggy C.
Published: June 2012

Ampicillin resistance (minimal inhibitory concentration ≥10 μg/ml) in the absence of beta-lactamase activity by
Haemophilus influenzae
was noted in tests performed with Mueller-Hinton agar containing one lot of supplement C. All strains, except five with known resistance due to beta-lactamase activity, were inhibited by 0.6 μg or less of ampicillin per ml of chocolatized blood agar.
PC-904, a Novel Broad-Spectrum Semisynthetic Penicillin with Marked Antipseudomonal Activity: Microbiological Evaluation
Authors: Noguchi H. , Eda Y. , Tobiki H. , Nakagome T. , Komatsu T.
Published: June 2012

PC-904, sodium 6-{
d
(−)-α-(4-hydroxy-1,5-naphthyridine-3-carboxamido) phenylacetamido}-penicillanate, is a novel semisynthetic penicillin derivative that possesses a broad spectrum of in vitro and in vivo antibacterial activities. In low concentrations, PC-904 inhibits growth against large proportions of the gram-positive and gram-negative organisms susceptible to carbenicillin and gentamicin. In addition, PC-904 is several times more potent than carbenicillin against organisms such as
Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Shigella, Salmonella, Neisseria gonorrhoeae
, and
Bacteroides fragilis
. Most striking are the inhibitory effects of PC-904 against
P. aeruginosa
and
K. pneumoniae
. Against these two clinical isolates, PC-904 is, respectively, 35 and 100 times more active than carbenicillin. The minimum inhibitory concentrations of PC-904 against
P. aeruginosa
are comparable to those of gentamicin. PC-904 acts bactericidally. The effect of inoculum size on the antibacterial activity is often small and generally comparable to carbenicillin. The rate of binding to serum protein is high (88 to 98%), but the effect of the addition of serum on the drug's activity is not marked, because such binding is reversible. It is confirmed that PC-904 has a very potent in vivo antibacterial activity against gram-negative and gram-positive organisms. Against systemic infections with
P. aeruginosa, K. pneumoniae
, and
E. coli
in mice, PC-904 is 7 to 10 times, over 8 times, and 2 to 15 times more active than carbenicillin, respectively.
Electrically Generated Silver Ions: Quantitative Effects on Bacterial and Mammalian Cells
Authors: Berger T. J. , Spadaro J. A. , Chapin S. E. , Becker R. O.
Published: June 2012

The inhibitory and bactericidal concentrations of electrically generated silver ions were 10 to 100 times lower than for silver sulfadiazine. Effects on normal mammalian cells were minimal.
Activity of Four Cephalosporin Antibiotics In Vitro Against Bovine Udder Pathogens and Pathogenic Bacteria Isolated from Newborn Calves
Authors: Ziv G.
Published: June 2012

The in vitro activity of chephaloridine, cephalexin, cefatrizine (BL-S640), and cephapirin (BL-P-1322) was evaluated by the serial dilution method against pathogenic gram-positive and gram-negative bacteria isolated from bovine udders and neonatal calf diseases. Cephapirin showed the comparatively greatest activity against the most common streptococcal species associated with bovine mastitis, whereas cephaloridine exhibited the best activity against
Staphylococcus aureus
. Cefatrizine was more active than the other cephalosporins against the gram-negative bacteria studied. In general, the minimal bactericidal concentration of each cephalosporin was two- to fourfold lower than the comparative value reported in the literature against the same type of pathogen of human origin.
A New Actinomycin Complex Produced by a
Micromonospora
Species: Fermentation, Isolation, and Characterization
Authors: Wagman G. H , Marquez J. A. , Watkins P. D. , Gentile F. , Murawski A. , Patel M. , Weinstein M. J.
Published: June 2012

A species of
Micromonospora, Micromonospora floridensis
NRRL 8020, has been found to produce an actinomycin complex consisting of at least 25 active components. After solvent extraction of the complex, separation of the individual components was carried out by preparative thin-layer chromatography. Hydrolysis and subsequent electrophoretic and chromatographic identification of the amino acid content of each of the isolated components have shown differences from known actinomycins, and the probability exists that these contain a number of amino or imino acids not previously found in other members of this group of antibiotics.
Cefuroxime, a New Cephalosporin Antibiotic: Activity In Vivo
Authors: Ryan D. M. , O'Callaghan Cynthia H. , Muggleton P. W.
Published: June 2012

The pharmacokinetic properties of cefuroxime have been evaluated in laboratory animals. On injection into mice, rats, and rabbits by the subcutaneous or intramuscular routes, high serum level peaks were recorded. There was no significant absorption after oral administration. After injection, the antibiotic was excreted in large amounts in the urine. It was well distributed in the body and penetrated into the tissues at a satisfactory rate. This, coupled with a low degree of serum protein binding, was correlated with a very good protective effect in animals (mice, rats, and rabbits) experimentally infected with a wide range of bacteria, including β-lactamase-producing strains. It is concluded that cefuroxime should have a good potential for treating a wide range of bacterial infections in humans.
Isolation and Characterization of Tetracycline Resistance Proteins from
Staphylococcus aureus
and
Escherichia coli
Authors: Wojdani Aristo , Avtalion Rami R. , Sompolinsky David
Published: June 2012

Immunoglobulin (adsorbed resistance antiserum) reacting specifically with antigens from tetracycline (Tc)-resistant
Staphylcoccus aureus
or
Escherichia coli
was produced by adsorbing immunoglobulin against cell envelopes of resistant strains with envelope extracts from the respective isogenic susceptible strains. Adsorbed resistance antiserum against
S. aureus
reacted with envelope extracts from 32 Tc-resistant strains and failed to react with similar extracts from 76 Tc-susceptible strains of
S. aureus
. An antigen (Tc resistance antigen [TRA]) found only in Tc-resistant strains was produced by adsorbing envelope extracts from these strains with immunoglobulin against envelopes from isogenic Tc-susceptible strains. On immunodiffusion no cross-reactivity between TRAs from
S. aureus
and
E. coli
was observed. The TRAs behaved as proteins. The molecular weight of TRA from
S. aureus
was determined to be 32,000 and from
E. coli
to be 50,000. Data obtained by preliminary amino acid analysis of the TRAs are presented.
Inhibition of Bacterial Growth by the Nitrofurantoin Solvent Dimethylformamide
Authors: Barry A. L. , Lasner R. A.
Published: June 2012

For quantitative susceptibility tests, stock solutions of nitrofurantoin are often prepared in dimethylformamide. Since 1.0 or 2.0 ml of the solvent will inhibit microbial growth, currently recommended procedures for antimicrobic dilution tests should be modified by adding only 0.1 or 0.2 ml of stock drug solutions to the agar or broth medium.
Enhancement of rI
n
:rC
n
-Induced Interferon Production by Amphotericin B
Authors: Borden Ernest C. , Leonhardt Peggy H.
Published: June 2012

When mouse L929 cells are treated with amphotericin B before exposure to polyriboinosinic-polyribocytidylic acid or polyriboinosinic-polyribocytidylic acid-dextran, they make significantly more interferon than do cells not receiving amphotericin. This effect may be due to enhanced cell membrane penetration by the polynucleotide.
Effect of Cephalothin on Renal Cortical Concentrations of Gentamicin in Rats
Authors: Dellinger Patchen , Murphy Terrence , Barza Michael , Pinn Vivian , Weinstein Louis
Published: June 2012

Renal cortical concentrations of gentamicin were significantly lower in rats given this aminoglycoside and cephalothin simultaneously than in animals given gentamicin alone. This effect may be responsible, in part, for the reduction in nephrotoxicity reported previously in animals given the combination of drugs.
Minocycline Resistance in
Staphylococcus aureus:
Effect on Phage Susceptibility
Authors: Schaefler S. , Francois W. , Ruby C. L.
Published: June 2012

Tetracycline-resistant strains of
Staphylococcus aureus
are minocycline sensitive, with the exception of strains susceptible to phages of the 83A/84/85 complex and some methicillin-resistant strains of other phage types. Strains of the 83A/84/85 complex yield mutants with increased minocycline resistance. Transduction of minocycline resistance into the susceptible strain RN 450 was obtained with donor strains possessing either markers for both extrachromosomal tetracycline resistance
(tet)
and chromosomal tetracycline + minocycline resistance (
tmn
R), or only for chromosomal
tmn
R resistance. The chromosomal marker was differentiated from the extrachromosomal marker by the lack of detectable extrachromosomal deoxyribonucleic acid after transfer into strain RN 450, transfer into a
rec
+
strain, lack of transfer into
rec
−
acceptor strain, and cotransduction with chromosomal determinants for guanine biosynthesis. Both chromosomal and extrachromosomal tetracycline resistance can be induced by tetracycline. Induction by tetracycline of chromosomal tetracycline resistance resulted in simultaneous induction of minocycline resistance. The mutation toward increased minocycline resistance (
tmn
→
tmn
R) is a regulatory mutation toward constitutivity or semiconstitutivity. Constitutive resistance is dominant in
tmn
R/
tet
diploids. Transfer of the
tet
marker does not affect the phage susceptibility of the acceptor strain. The
tmn
R marker, originating from donor strains of the 83A/84/85 complex, renders strain RN 450 resistant to several typing phages, with the exception of phages of the 83A/84/85 complex. This could possibly account for the phage typing patterns of minocycline-resistant staphylococci.
Effect of Amphotericin B on Growth and Membrane Permeability in
Dictyostelium discoideum
Authors: Rossomando Edward F. , Creme Gerard , Maldonado Barbara , Hesla Mary Ann , Golub Ellis E.
Published: June 2012

In this study we have determined the effect of the polyene antibiotic amphotericin B on the growth of the eukaryotic microorganism
Dictyostelium discoideum
. These experiments show that the addition of drug to axenically growing cultures results in an inhibition of growth and cell division. However, with continued incubation, growth is resumed. To determine if the inhibitory effect was due to cell death, the effect of the drug on cell viability was measured. The results showed 10 to 20 times more drug was required to kill cells than to inhibit growth. Since previous studies had indicated that drugs of this type modified cellular permeability, the effect of this drug on osmotic stability of these cells was determined. Results reported in this study show that amphotericin B treatment modifies the cell surface, producing osmotically unstable cells, and that this modification occurs before the onset of cell death and within the same concentration range as used to bring about the inhibition of growth and division. Based on these data it is suggested that the modification in cellular permeability produced by the drug results in the inhibition of growth. This study also reports the results of experiments on the fate of the membrane-damaged cells. These experiments, using radioactive thiourea, showed the restoration of cellular permeability barrier and suggested that the resumption of cell growth occurs after the completion of the repair process.
Comparison and Evaluation of Ticarcillin and Carbenicillin Using Disk Diffusion Methods
Authors: Parry Michael F. , Neu Harold C.
Published: June 2012

Ticarcillin has proved to be two- to fourfold more active than carbenicillin against most strains of
Pseudomonas aeruginosa
. Although susceptibility of the
Enterobacteriaceae
to ticarcillin could be predicted from results obtained with carbenicillin disks, neither the 50-μg nor the 100-μg carbenicillin disk proved suitable for testing susceptibility of
P. aeruginosa
to ticarcillin. Forty-three percent of
Pseudomonas
strains judged to be resistant to carbenicillin by the 100-μg carbenicillin disk were susceptible to ticarcillin by agar dilution studies. Results obtained with a 75-μg ticarcillin disk showed excellent correlation between zone size and ticarcillin minimal inhibitory concentration values and produced good discrimination between resistant and susceptible strains of
Pseudomonas
as determined by agar dilution studies. Using a 75-μg ticarcillin disk, a zone size of 12 to 14 mm was appropriate for designating intermediate susceptibility, and a zone greater than or equal to 15 mm was appropriate for designating susceptible strains of both
P. aeruginosa
and the
Enterobacteriaceae
.
Synergy of Mecillinam (FL1060) with Penicillins and Cephalosporins Against
Proteus
and
Klebsiella
, with Observations on Combinations with Other Antibiotics and Against Other Bacterial Species
Authors: Baltimore Robert S. , Klein Jerome O. , Wilcox Clare , Finland Maxwell
Published: June 2012

Thirty-five strains each of
Klebsiella
and
Proteus
were tested for susceptibility to mecillinam alone and in combination with ampicillin, carbenicillin, cephalothin, and cefazolin. Antibiotics were considered to be synergistic when there was a ≥fourfold reduction in minimum inhibiting concentration of both antibiotics in the combination as compared with that of each antibiotic alone. Synergy of mecillinam with ampicillin, carbenicillin, cephalothin, and cefazolin was demonstrated against 2, 3, 7, and 8 of the 35 strains of
Klebsiella
and against 14, 14, 19, and 24 of the 35 strains of
Proteus
, respectively. Synergy against the isolates of
Proteus
was related to species, whereas against
Klebsiella
it was related to susceptibility of the isolates to mecillinam. Tests of combinations of mecillinam with other antibiotics on the same and different species indicated that synergy was related to the antibiotic, the species, and the strains of organisms tested.
Quantitation of Antibiotics Using High-Pressure Liquid Chromatography: Tetracycline
Authors: Nilsson-Ehle Ingrid , Yoshikawa Thomas T. , Schotz Michael C. , Guze Lucien B.
Published: June 2012

A method for quantitative determination of tetracycline in serum, using high-pressure liquid chromatography, is reported. After extraction of the drug from serum, using methanol-trichloroacetic acid solution, tetracycline was separated by reverse-phase chromatography. Quantitation of tetracycline was based on a linear relationship between peak heights in the chromatograms and known concentrations of the drug in the original serum samples. Serum tetracycline concentrations as low as 0.3 μg/ml could be accurately measured. Serum samples obtained after a single intravenous injection of tetracycline to three human volunteers and six dogs were assayed by microbiological and chemical assays. Correlation coefficients of 0.95 and 0.97, respectively, were found. This chemical method is rapid (less than 30 min), accurate, sensitive, and reproducible, and it seems feasible for routine clinical use.
Clinical Pharmacokinetics of Sisomicin: Dosage Schedules in Renal-Impaired Patients
Authors: Pechère Jean-Claude , Pechère Marie-Madeleine , Dugal Robert
Published: June 2012

The pharmacokinetics of intravenously administered sisomicin were studied in 33 patients with normal renal function and different degrees of renal impairment. In all patients, the serum disappearance of sisomicin, once distribution equilibrium had been achieved, followed first-order kinetics and percentage of hourly loss from serum decreased proportionally with decreasing renal function. Half-lives averaged 2.06 h in normal subjects (endogenous creatinine clearance greater than 80 ml/min per 1.73 m
2
) and reached 35.3 h in a virtually anephric subject. Linear relationships were defined between sisomicin serum half-life and the reciprocal of the endogenous creatinine clearance and serum creatinine concentration. The latter relationship indicates that the half-life of sisomicin may be approximated as twice the serum creatinine concentration and may be used for dosage adjustment in renal-impaired patients. Prediction of the extent of sisomicin removal by hemodialysis may be made from the relationship between the dialyzate of sisomicin and that of creatinine and blood urea nitrogen. Dosage schedules and methods of administration compatible with the pharmacokinetic properties of the antibiotic are finally proposed.
Cefatrizine (SK&F 60771), a New Oral Cephalosporin: Serum Levels and Urinary Recovery in Humans After Oral or Intramuscular Administration – Comparative Study with Cephalexin and Cefazolin
Authors: Actor Paul , Pitkin Donald H. , Lucyszyn George , Weisbach Jerry A. , Bran José L.
Published: June 2012

Cefatrizine (SK&F 60771), a new broad-spectrum cephalosporin, was administered in a 0.5-g dose either orally or intramuscularly to volunteers in a crossover study. After oral administration, the average peak serum levels were 5.6 and 22.1 μg/ml for cefatrizine and cephalexin, respectively. The serum half-life of cefatrizine appeared to be more extended than that of cephalexin. Urinary recovery of cefatrizine (35%) was approximately half that of cephalexin (68%) after oral administration. After intramuscular injection of 0.5 g, the average peak serum level of cefatrizine (12.0 μg/ml) was approximately one-fourth that of cefazolin (44.0 μg/ml). The serum half-life after intramuscular injection was 86 min for cefatrizine and 118 min for cefazolin. Urinary recovery was 45% of the intramuscularly administered dose, as compared with cefazolin, which was 74%.
In Vitro Susceptibilities of Anaerobic Bacteria to Josamycin
Authors: Long Sarah S. , Mueller Suzanne , Swenson Robert M.
Published: June 2012

A total of 132 strains of anaerobic bacteria were tested for susceptibility to josamycin, using a broth dilution technique. All strains of
Peptococcus
species,
Peptostreptococcus
species, and
Bacteroides fragilis
were inhibited by 2 μg or less per ml. Seventy percent of these susceptible strains were also killed by 2 μg or less of josamycin per ml. However, 2 of 12
Clostridium
species and 6 of 10
Fusobacterium
species had minimum inhibitory concentrations of 32 μg or more per ml.
Phenylalanine Stimulation of Gramicidin S Formation
Authors: Demain Arnold L. , Matteo Charles C.
Published: June 2012

Bacillus brevis
produces the antibiotic gramicidin S, a cyclic peptide comprised of two pentapeptide units of the sequence
d
-Phe-
l
-Pro-
l
-Val-
l
-Orn-
l
-Leu. Synthesis of this antibiotic is carried out by two enzymes, GS synthetases I and II. By supplementing a defined minimal medium [glycerol, NH
4
+
, tris(hydroxymethyl)aminomethane, salts] with each of the constituent amino acids (in the
l
form), we found that only
l
-phenylalanine had a marked stimulatory effect on gramicidin S production. This effect was not caused by an increase in growth, by an induction of GS synthetases I or II, or by a stabilization of these enzymes.
l
-Phenylalanine apparently stimulates production via its role as a precursor of the
d
-phenylalanine moiety of the gramicidin S molecule.
Bacteriological Study on Effects of Beta-Lactam Group Antibiotics in High Concentrations
Authors: Nishino Takeshi , Nakazawa Shozo
Published: June 2012

The growth and viability of
Staphylococcus aureus, Escherichia coli
, and
Pseudomonas aeruginosa
exposed to various concentrations of a number of β-lactam group antibiotics were determined. In
S. aureus
, the bacteriolytic and bactericidal activity of these drugs was lower at very high drug concentrations than that occurring at low concentrations, but these phenomena were not observed in
E. coli
and
P. aeruginosa
. Under phase-contrast and scanning electron microscopy,
S. aureus
treated with high concentrations of β-lactam group antibiotics revealed a lower frequency of bacteriolysis than at low drug concentrations, and similarly by transmission electron microscopy fewer cells were transformed into spheroplasts at high drug concentrations. However, swelling of the cell wall septum was seen in many cells. Spheroplast formation occurred with the highest frequency at drug levels near the minimum inhibitory concentration and became less frequent as drug concentrations were increased.
Comparison of In Vitro Antimicrobial Activity of Cefamandole and Cefazolin with Cephalothin Against over 8,000 Clinical Bacterial Isolates
Authors: Jones Ronald N. , Fuchs Peter C.
Published: June 2012

Antimicrobial susceptibility to cefamandole versus cephalothin and cefazolin versus cephalothin was compared by the broth microdilution method against 3,000 and 5,895 clinical bacterial isolates, respectively. Cefamandole and, to a lesser degree, cefazolin showed greater activity than cephalothin against
Enterobacteriaceae
, but the three drugs were comparable against gram-positive cocci.
Characterization of an Ampicillin-Resistant
Haemophilus influenzae
Type B
Authors: Eickhoff Theodore C. , Ehret Josephine M. , Baines R. Dixie
Published: June 2012

A 28-year-old female in Denver was found in early 1974 to have frontal sinusitis, osteomyelitis, and bacteremia due to
Haemophilus influenzae
, type B. The minimal inhibitory concentration of ampicillin for this organism was 100 μg/ml and the minimal bactericidal concentration was >100 μg/ml. It was inhibited by chloramphenicol at 0.4 μg/ml. Further studies demonstrated that ampicillin and methicillin were synergistic against this organism. It was shown to produce a diffusible beta-lactamase. Transferase of resistance from this organism to a susceptible
Haemophilus parainfluenzae
and a reciprocal transfer were accomplished. A test for transformation was negative as was a test for reversal of resistance by ethylenediaminetetraacetic acid.
Reevaluation of Kanamycin Dosage in Infants and Children
Authors: Hieber J. Patrick , Nelson John D.
Published: June 2012

It was recently reported that the dosage of kanamycin formerly recommended for neonates of 7.5 mg/kg every 12 h did not produce therapeutic serum concentrations of 15 to 25 μg/ml, but a larger dosage of 10 mg/kg every 12 h was required. Reevaluation of the pharmacokinetics of kanamycin in infants and children was therefore undertaken. Sixteen time-concentration curves after a dose of 5 mg/kg were obtained from patients 2 months to 12 years of age; the mean peak serum kanamycin concentration was 10.9 (range, 3.6 to 17.9) μg/ml at 0.5 h. Ten time-concentration curves were obtained after a dose of 10 mg/kg; the mean peak serum concentration was 17.6 (range, 8.4 to 30) μg/ml. Eight patients were studied on successive days, and there was doubling of the 1-h peak serum concentration when the dose of kanamycin was increased from 5 to 10 mg/kg. Standard serum bactericidal tests were done against
Escherichia coli
and
Enterobacter cloacae
strains, each with a minimal bactericidal concentration of 5 μg of kanamycin per ml. All 3 sera containing 21 μg or more of kanamycin per ml demonstrated a bactericidal titer, whereas only 2 of 23 sera containing less than 21 μg of kanamycin per ml did so. The currently recommended dosage of kanamycin for infants and children fails to produce serum concentrations in the therapeutic range, and preliminary data suggest that the dosage should be increased to 10 mg/kg per dose every 8 h.
Mechanism of Action of Miconazole: Labilization of Rat Liver Lysosomes In Vitro by Miconazole
Authors: Swamy K. H. Sreedhara , Joshi Aruna , Rao G. Ramananda
Published: June 2012

Miconazole, a potent antifungal agent, labilizes rat liver lysosomes. Its labilizing effect is followed by measuring the release of lysosomal hydrolases, namely, acid phosphatase, β-glucuronidase, and arylsulfatase A. The effect of miconazole is concentration dependent in the range of 10
−5
to 1.2 × 10
−4
M. However, at higher concentrations, miconazole inhibits enzyme release but does not inhibit enzyme activities per se. The effect of miconazole depends on the drug/lysosome ratio and is influenced by the pH of the incubation media, being minimal at alkaline pH. Membrane-active drugs such as nystatin, 2-phenethyl-alcohol, hexachlorophene, and digitonin have been compared with miconazole for their lysosome-labilizing action. The effect of miconazole on the lysosomal membrane is confirmed by a decrease in turbidity of the lysosomal suspension.
Genome Sequences of Three Species in the Family Planctomycetaceae
Authors: Guo Min , Han Xifang , Jin Tao , Zhou Lisha , Yang Jinlong , Li Zihua , Chen Jing , Geng Bin , Zou Yuanqiang , Wan Daiwei , Li Daocheng , Dai Wenkui , Wang Hui , Chen Yanling , Ni Peixiang , Fang Chengxiang , Yang Ruifu
Published: June 2012

Most of the species in the family
Planctomycetaceae
are of interest for their eukaryotic-like cell structures and characteristics of resistance to extreme environments. Here, we report draft genome sequences of three aquatic parasitic species of this family,
Singulisphaera acidiphila
(DSM 18658T),
Schlesneria paludicola
(DSM 18645T), and
Zavarzinella formosa
(DSM 19928T).
Perceived role in end-of-life decision making in the NICU affects long-term parental grief response
Authors: Caeymaex Laurence , Jousselme Catherine , Vasilescu Caroline , Danan Claude , Falissard Bruno , Bourrat Marie-Michèle , Garel Micheline , Speranza Mario
Published: June 2012

Background

Shared decision making (DM) is increasingly advocated as the most appropriate model to support parents confronted with end-of-life (EoL) decisions for a child in the neonatal intensive care unit (NICU). However, few studies have explored its impact on their long-term grief.

Objectives

The aim of this study was to investigate whether parental perception of the type of involvement in the EoL decision-making process (EoL DMP) for their child in the NICU is related to their long-term grief outcome.

Methods

A retrospective study with mixed methods. The study included parents whose child died from 2002 through 2005 in one of four NICUs in different areas in France, with interviews of 78 individual parents of 53 children, 2.7±0.6 years after the child's death. Parental perception of the type of involvement in the EoL DMP was determined by qualitative analysis of face-to-face interviews and classified as follows: shared, medical, informed parental and no decision. Grief reactions were assessed with the Texas Revised Inventory of Grief (TRIG-F).

Results

Current grief scores differed significantly according to the perceived type of EoL DM. Shared DM was associated with lower TRIG-F scores (less grief) than were the other types of EoL DM (F=7.95; p=0.05). The baby's perceived suffering was also associated with higher grief scores (F=6.51, p=0.01).

Conclusions

In decisions to forego life-sustaining treatment in the NICU, the perception of a shared decision is associated in the long term with lower grief scores than perceptions of the other types of DM.
Gene cloning, molecular modeling, and phylogenetics of serine protease P32 and serine carboxypeptidase SCP1 from nematophagous fungiPochonia rubescensandPochonia chlamydosporia
Authors: Larriba Eduardo , Martín-Nieto José , Lopez-Llorca Luis Vicente
Published: June 2012

The fungi Pochonia chlamydosporia and Pochonia rubescens are parasites of nematode eggs and thus are biocontrol agents of nematodes. Proteolytic enzymes such as the S8 proteases VCP1 and P32, secreted during the pathogenesis of nematode eggs, are major virulence factors in these fungi. Recently, expression of these enzymes and of SCP1, a new putative S10 carboxypeptidase, was detected during endophytic colonization of barley roots by these fungi. In our study, we cloned the genomic and mRNA sequences encoding P32 from P. rubescens and SCP1 from P. chlamydosporia. P32 showed a high homology with the serine proteases Pr1A from the entomopathogenic fungus Metarhizium anisopliae and VCP1 from P. chlamydosporia (86% and 76% identity, respectively). However, the catalytic pocket of P32 showed differences in the amino acids of the substrate-recognition sites compared with the catalytic pockets of Pr1A and VCP1 proteases. Phylogenetic analysis of P32 suggests a common ancestor with protease Pr1A. SCP1 displays the characteristic features of a member of the S10 family of serine proteases. Phylogenetic comparisons show that SCP1 and other carboxypeptidases from filamentous fungi have an origin different from that of yeast vacuolar serine carboxypeptidases. Understanding protease genes from nematophagous fungi is crucial for enhancing the biocontrol potential of these organisms.
Adaptation of a real-time PCR method for the detection and quantification of pathogenic leptospires in environmental water
Authors: Vein Julie , Perrin Aurélie , Berny Philippe J. , Benoit Etienne , Leblond Agnès , Kodjo Angeli
Published: June 2012

Leptospirosis is a major zoonotic disease that affects humans and animals in all continents, in both rural and urban areas. In Europe, metropolitan France is the most affected country, with about 300 human cases declared per year. In France, although leptospirosis is now mostly considered as a recreational disease related to freshwater areas, isolation of pathogenic leptospires from environmental water samples still remains difficult. It thus seemed important to set up an efficient method to detect and quantify these bacteria in this environment. We determined a DNA extraction method suitable for freshwater samples and adapted a real-time quantitative PCR based on the detection of the LipL32 gene using the SYBR green chemistry. The method developed is specific for pathogenic Leptospira. It permits the detection of all the pathogenic strains tested and none of the saprophytic strains. Quantification is possible between 10 and 107 bacteria/mL, and therefore, the method represents a tool that could be integrated into future public health surveillance programs for recreational freshwater areas.
FEATURE WEIGHTING FUZZY CLUSTERING INTEGRATING ROUGH SETS AND SHADOWED SETS
Authors: WANG LINA , WANG JIANDONG
Published: June 2012

Associating features with weights is a common approach in clustering algorithms and determining the weight values is crucial in generating valid partitions. In this paper, we introduce a novel method in the framework of granular computing that incorporates fuzzy sets, rough sets and shadowed sets, and calculates feature weights automatically. Experiments on synthetic and real data patterns show that our algorithms always converge and are more effective in handling overlapping among clusters and more robust in the presence of noisy data and outliers.