bluuebunny/crossref_metadata_2025 huggingface dataset:
Proposed Standardized Method for Testing and Interpreting Susceptibility of
Bacteroides fragilis
to Tetracycline
Authors: Overman Sue B. , Lambe Dwight W. , Bennett John V.
Published: June 2012

One hundred twenty-four strains of
Bacteroides fragilis
were examined for susceptibility to tetracycline disks and by minimal inhibitory concentration (MIC) determinations. MIC values and zone sizes around 30-μg tetracycline disks were determined by using selected test conditions which included Mueller-Hinton agar supplemented with sheep blood, vitamin K, and hemin and an incubation temperature of 35 C in an atmosphere of 80% N
2
, 10% H
2
, and 10% CO
2
. Strains were separated into two distinct populations by geometric mean MIC and dis tests. Of the 124 strains, 78 were resistant and 46 were susceptible. The resistant strains had geometric mean MIC's of 8 μg/ml or greater, whereas the geometric mean MIC's of sensitive strains were 5 μg/ml or less. The disk test proved to be more reproducible than the MIC test and completely separated the resistant and susceptible populations. An interpretive scheme for
B. fragilis
to tetracycline was statistically derived on the basis of the distribution of zone sizes of susceptible and resistant strains: resistant, 18 mm or less; indeterminant, 19 to 20 mm; and susceptible, 21 mm or greater. These zone sizes compared closely with the Kirby-Bauer criteria for aerobic bacteria.
Effects of Some Antiviral Isatinisothiosemicarbazones on Cellular and Viral Ribonucleic Acid Synthesis in Mengovirus-Infected FL Cells
Authors: Tonew Marion , Tonew E.
Published: June 2012

Three antiviral isatinisothiosemicarbazones strongly inhibited the incorporation of [
3
H]uridine into the ribonucleic acid (RNA) of FL cells as a consequence of the inhibition of uridine transport. After prelabeling of cells at a low temperature (1 h at 16 C) with uptake of [
3
H]uridine into the acid-soluble nucleotide pool, the later addition of the test compounds revealed only a small or negligible influence on host-directed RNA synthesis. The pulse-labeled soluble nucleotide pool of FL cells was sufficient to give a gradual increase in incorporation into RNA over a period of 7 h. With the same method of prelabeling at the beginning of the experiment, it was also possible to detect virus-induced RNA synthesis in the presence of actinomycin D. In this way the specific inhibitory action of the three isatinisothiosemicarbazones on viral RNA synthesis could be demonstrated.
Studies on the Mechanism of Action of Miconazole: Effect of Miconazole on Respiration and Cell Permeability of
Candida albicans
Authors: Swamy K. H. Sreedhara , Sirsi M. , Rao G. Ramananda
Published: June 2012

The antifungal drug, miconazole nitrate, inhibits the growth of several species of
Candida. Candida albicans
, one of the pathogenic species, was totally inhibited at a concentration of approximately 10 μg/ml. Endogenous respiration was unaffected by the drug at a concentration as high as 100 μg/ml, whereas exogenous respiration was markedly sensitive and inhibited to an extent of 85%. The permeability of the cell membrane was changed as evidenced by the leakage of 260-nm absorbing materials, amino acids, proteins, and inorganic cations. The results we present clearly show that the drug alters the cellular permeability, and thus the exogenous respiration becomes sensitive to the drug.
Synergistic Effect of Pactamycin and Sparsomycin on
Mycoplasma
-Induced Lethal Toxicity of Mice
Authors: Gabridge Michael G.
Published: June 2012

Pactamycin and sparsomycin, antitumor drugs which act synergistically with endotoxins, also potentiate the lethal toxicity of mice by
Mycoplasma fermentans
, strain K10. Sparsomycin (50 μg/20 g mouse, injected intraperitoneally 1 h after various doses of
M. fermentans
) exerted a minimal degree of synergism with few extra deaths, but with prolonged appearance of nonlethal disease. Pactamycin (75 μg in the same protocol) increased susceptibility to
Mycoplasma
-induced lethal toxicity approximately 1,000-fold. The optimal response was noted when pactamycin was administered in the period between 6 h before and 3 h after the administration of 10
8
colony-forming units of viable mycoplasmas. Doses of 12.5, 25, or 50 μg increased severity of signs, but only 75 μg/mouse produced synergism of the lethal effect. Methylprednisolone partially negated the synergism when injected simultaneously with the pactamycin 1 h after the cells. The lethal synergistic effect occurred with four species of
Mycoplasma
in addition to
M. fermentans
.
Susceptibility of Anaerobic Bacteria to Carbenicillin
Authors: Blazevic Donna J. , Matsen John M.
Published: June 2012

One hundred and seventy-one strains of anaerobes were tested for susceptibility to carbenicillin by using agar dilution, broth dilution, and two disk diffusion methods. The minimal inhibitory concentration (MIC) for 67% of 51 strains of
Bacteroides fragilis
, 7 of 9 strains of
Bacteroides melaninogenicus
, and all of 8 strains of
Eubacterium
was 100 μg or less per ml. The MICs of the remaining anaerobes were 50 μg or less per ml. The broth dilution results were felt to be the most accurate of the four methods utilized.
Combined Amphotericin B-Tetracycline Therapy for Experimental Coccidioidomycosis
Authors: Huppert M. , Sun Sung H. , Vukovich Katherine R.
Published: June 2012

Although amphotericin B is the principal antibiotic for treating systemic mycoses, its clinical use is restricted, primarily because of the toxicity associated with the required prolonged therapy. Other investigators have reported results from in vitro experiments demonstrating that amphotericin B can potentiate antifungal activity of other antibiotics which are ineffective when used alone. In the present study, amphotericin B was used in combination with tetracycline for treating experimental coccidioidomycosis in mice. The results show that the combination of antibiotics is effective with a dosage of amphotericin B reduced 2.5 to 4 times of that required for effective chemotherapy with amphotericin B alone.
Mutant of
Staphylococcus aureus
with Lincomycin- and Carbomycin-Inducible Resistance to Erythromycin
Authors: Tanaka Teruo , Weisblum Bernard
Published: June 2012

A mutant of
Staphylococcus aureus
was isolated in which lincomycin and carbomycin (but not erythromycin) induced resistance to erythromycin. This pattern displayed a reversal of the usual specificity of induction seen in the erythromycin-inducible parent strain from which the mutant was selected.
Effect of Carbon Dioxide on Synthesis of Erythromycin
Authors: Nash Claude H.
Published: June 2012

Erythromycin synthesis was markedly impaired in submerged cultures under high carbon dioxide tensions. Growth of
Streptomyces erythreus
, however, was unaltered by increased carbon dioxide.
Potential Unreliability of Nitrofurantoin Disks in Susceptibility Testing
Authors: Hoo Robert , Drew W. Lawrence
Published: June 2012

The Kirby-Bauer disk diffusion antimicrobial susceptibility test was studied with three lots of commercial nitrofurantoin disks by using 50 strains of
Proteus mirabilis
. One lot of disks consistently gave zone diameters 3 to 6 mm larger than the other two and resulted in a substantial number of
Proteus mirabilis
strains being erroneously categorized as sensitive. Antimicrobial content in disks of the three lots did not account for these differences. The pH of eluate from the unreliable disks was higher than from disks of the other two and resulted in more rapid diffusion of the antimicrobial and consequently larger zones of inhibition.
Effect of Clindamycin on Acute and Chronic Toxoplasmosis in Mice
Authors: Araujo Fausto G. , Remington Jack S.
Published: June 2012

The effect of clindamycin on survival of mice during acute infection with the RH and C56 strains of
Toxoplasma
and the ability of this drug to prevent congenital transmission during the acute stage of the infection in the mother and to eradicate the parasite from tissues of mice chronically infected with the C56 strain were evaluated. The drug effectively prevented death due to the acute infection and, in the experimental model employed, eradicated the organism at least from the liver, spleen, and brain of approximately 30 to 50% of the acutely infected animals which survived. Clindamycin also effectively prevented congenital transmission during the acute infection in the mother. During short-term treatment (7 days), persistent parasitemia in the chronic infection was effectively diminished or eradicated. More prolonged treatment resulted in a significant clearing of the organisms from the spleens and livers, but not from the brains, of chronically infected mice.
BRL.8988 (Talampicillin), a Well-Absorbed Oral Form of Ampicillin
Authors: Clayton J. P. , Cole M. , Elson S. W. , Ferres H.
Published: June 2012

The phthalidyl ester (BRL.8988, talampicillin) of ampicillin gave serum levels in man two and a half times those obtained with ampicillin itself.
R-Mediated β-Lactamases and Episomal Resistance to the β-Lactam Drugs in Different Bacterial Hosts
Authors: Kontomichalou Polyxeni M. , Papachristou Efstathia G. , Levis Gabriel M.
Published: June 2012

Ten penicillinase plasmids of varying taxonomic origin were studied after transfer to a variety of bacterial hosts. Nine of the ten plasmids specified enzymes with the following identical, or very similar, properties: substrate profile, molecular weight, susceptibility to heat and inhibitors, and electrophoretic mobility, i.e., TEM-like enzymes. The tenth R-mediated β-lactamase was a cephalosporinase. Plasmids with TEM-like enzymes mediated resistance patterns identical towards the β-lactam drugs, whereas the resistance pattern of the cephalosporinase plasmid was distinctly different. Expression of enzyme and resistance had a dual R-factor and host specificity.
Escherichia coli
K-12 and
Salmonella typhi
constituted one group of the same R-factor phenotype expressions. Most, but not all, penicillinase plasmids exhibited in
Proteus
PM1 a considerably lower order of β-lactamase activity and an even lower order of resistance to the β-lactam drugs than the previous two hosts. This difference was most pronounced for the resistance to carbenicillin, which was mediated by the plasmids specifying the synthesis of TEM-like enzymes. Release by osmotic shock was complete in the host
E. coli
K-12 for the TEM-like enzymes, but was lower for the cephalosporinase and minimal or negative in the PM1 host. Crypticity factor for benzylpenicillin, ampicillin, and carbenicillin was not related to the increase in resistance mediated by the penicillinase plasmids in both K-12 and PM1 hosts. Inoculum size effects for the penicillins and 6-aminopenicillanic acid were higher in PM1 than in K-12 R
+
cultures. The expression of penicillinase plasmids in wild-type bacteria was strain specific and not species specific. For two plasmids of different phenotypes for β-lactamase activity (and resistance) in K-12 and PM1 hosts, a positive correlation was found between their phenotype and the relative amount of episomal deoxyribonucleic acid, as detected by ethidium bromide density gradient centrifugation. This is interpreted as indicating differences in the mode of replication of the plasmids in the two hosts.
Lack of Activity of Sulfamethoxazole and Trimethoprim Against Anaerobic Bacteria
Authors: Rosenblatt J. E. , Stewart P. R.
Published: June 2012

The activity of sulfamethoxazole (SMX), trimethoprim (TMP), and the combination of the two was determined against a variety of anaerobic bacteria. Brucella agar was somewhat inhibitory for SMX and TMP but activity was good and equivalent in Diagnostic Sensitivity Test Agar (Oxoid) and Mueller-Hinton agar and the latter was selected for use in these studies. Agar dilution susceptibility tests showed that 95 of 98 anaerobic isolates were resistant to ≥100 μg of SMX per ml and 85 were resistant to ≥6.25 μg of TMP per ml. “Checkerboard” agar dilution studies of combined activity showed that 66 of 72 isolates were resistant to ≥ (100 μg of SMX per ml + 6.25 μg of TMP per ml) and only six isolates were susceptible to the synergistic activity of the combination. The majority of 32 isolates tested by the disk diffusion method were also resistant to SMX and TMP individually and to the combination 25-μg disk. Correlation between agar dilution minimal inhibitory concentration and disk zone size results was in general good for individual agents. Four
Bacteroides fragilis
isolates were inhibited by the combination 25-μg disk but were resistant to SMX + TMP by agar dilution “checkerboard.” This discrepancy may have been due to different incubation periods since disk results also showed resistance when read after 48 h (as is done with agar dilution) rather than the standard 24 h for disk tests. These studies suggest that SMX and TMP, either individually or in combination, are not active against the great majority of anaerobic bacteria.
Distribution in Nature of R factors that Increase Susceptibility to Rifampin of
rif-r
Mutants in
Escherichia coli
Authors: Scotti R. , Silvestri L. G. , Romero E.
Published: June 2012

Among 117 gram-negative bacteria isolated from pathological materials, 46 were found to carry antibiotic resistances transferable to
Escherichia coli
K-12; we therefore concluded that they carry infectious R factors. When transferred to a type of rifampin-resistant mutant of
E. coli
, all these R factors decreased the resistance to rifampin, but only 10% of them lowered the resistance to one-tenth or less that of the isogenic R
−
strain. The relevance of these facts for the epidemiology of R factors in gram-negative bacteria is discussed.
Comparative Serum Levels and Protective Activity of Parenterally Administered Cephalosporins in Experimental Animals
Authors: Fare Louis R. , Actor Paul , Sachs Carl , Phillips Lillian , Joloza MacDonald , Pauls John F. , Weisbach Jerry A.
Published: June 2012

Six cephalosporin antibiotics were administered subcutaneously to mice at a level of 20 mg/kg. The serum levels of each were determined at five time intervals ranging from 5 to 120 min after dosing. Urinary recovery and the presence of active metabolites in mouse urine were determined. The peak serum levels and serum half-lives in mice were found to be positively correlated with the mean effective dose values obtained after lethal challenge with
Escherichia coli
. The administration of cefazolin and cephanone resulted in the highest serum level and the best protection. Good protection was obtained with cephaloridine despite somewhat lower serum levels. The cephalosporins with the acetoxy side chain (cephalothin, cephapirin, and cephacetrile) showed lower serum levels and the poorest protection. Cefazolin, cephaloridine, and cephalothin serum levels were also determined in dogs, squirrel monkeys, and rabbits. A mixed response was obtained in these species, with cefazolin peak serum levels being highest in rabbits and cephaloridine peak highest in dogs.
Diphtheria Carriers and the Effect of Erythromycin Therapy
Authors: Miller Louis W. , Bickham Susan , Jones Wallis L. , Heather Carl D. , Morris Roy H.
Published: June 2012

One hundred and fourteen
Corynebacterium diphtheriae
, toxigenic, gravis type, pharyngeal carriers were identified during a diphtheria epidemic in Elgin, Texas. All carriers were treated with erythromycin estolate, 1 g/day in divided doses for 6 days. Serial pharyngeal cultures were obtained in order to monitor the bacteriological response. Seventy-two carriers had positive cultures immediately prior to the start of therapy, and only these individuals were considered in the analysis of the effects of erythromycin. Forty-eight hours after institution of therapy, 96% of the carriers had become culture negative; all were negative by the 4th day of therapy, and all remained culture negative while taking the drug. Two days after cessation of therapy, all but one (99%) were culture negative. However, upon reculture 2 weeks later, 15 (21%) had relapsed to the carrier state. There were no significant differences in the serum diphtheria antitoxin levels, immunization status, age, sex, or socioeconomic status of those who relapsed and those who remained culture negative. This study demonstrates that erythromycin is effective in converting carriers to culture-negative status, but when given for only 6 days it is associated with large numbers of relapses. Because previous studies have not included follow-up cultures 2 weeks after therapy, it is suggested that all
C. diphtheriae
carriers be treated with either erythromycin or penicillin and that all be recultured at a minimum of 2 weeks after completion of therapy to assure eradication of the diphtheria organisms.
Relationship Between the Structures of Fatty Acid Amide Derivatives and Their Antimicrobial Activities
Authors: Ōmura Satoshi , Katagiri Michiko , Awaya Juichi , Furukawa Tokio , Umezawa Iwao , Ōi Nobuhiro , Mizoguchi Masakazu , Aoki Bunya , Shindo Minoru
Published: June 2012

The structure-activity relationships of derivatives of the antibiotic cerulenin were investigated by chemically modifying dodecanoic acid, its skeletal back-bone. The dimethylamide derivatives were active against both gram-positive and -negative bacteria, and fungi. Among the compounds having modified groups at positions C2 and C4, the most active were those with a carbonyl group at C4 and a double bond at C2. The dimethylamide and pyrrolidine amide derivatives of this structure type were the most active. Activity against bacteria and yeast increased with the number of carbon atoms in the skeleton, with the maximum activity being observed at C=12. No significant differences in activity against fungi were observed with change in chain length.
Antimicrobial Susceptibilities of Anaerobic Bacteria: Recent Clinical Isolates
Authors: Staneck Joseph L. , Washington John A.
Published: June 2012

Minimal inhibitory concentrations of clindamycin, minocycline, metronidazole, penicillin, and carbenicillin were determined by agar dilution against 150 recent clinical isolates of anaerobic bacteria. Ninety-nine percent of
Bacteroides fragilis
and all
B. melaninogenicus, Clostridium perfringens
, and
Fusobacterium
were inhibited by clindamycin at 3.1 μg/ml. Only 58% of other clostridial species were inhibited by this concentration of clindamycin. Minocycline at 3.1 μg/ml inhibited 72% of
C. perfringens
, 81% of other
Clostridium
species, and 66, 75, and 100% of
B. fragilis, B. melaninogenicus
, and
Fusobacterium
, respectively. Metronidazole at 12.5 μg/ml inhibited all bacteria tested.
B. fragilis
was resistant to both penicillin and carbenicillin at 6.2 μg/ml. Concentrations of 25 μg/ml for penicillin and 100 μg/ml for carbenicillin were needed to inhibit more than 90% of
B. fragilis
. Organisms other than
B. fragilis
were moderately or extremely susceptible to the penicillins.
Dihydrofolate Reductase in
Pediococcus cerevisiae
Strains Susceptible and Resistant to Amethopterin
Authors: Mandelbaum-Shavit Frederika , Grossowicz Nathan
Published: June 2012

A mutant strain of
Pediococcus cerevisiae
was obtained which had 1,000-fold greater resistance to amethopterin than the
P. cerevisiae
/PteGlu strain. The dihydrofolate reductase level of the mutant was about 60-fold higher than that of the parent. The mutant accumulated folate, though less efficiently than its parent.
Biochemical and Genetic Basis of Tetracycline Resistance in
Staphylococcus aureus
Authors: Chopra I. , Lacey R. W. , Connolly Janet
Published: June 2012

Both the genetic and biochemical basis of tetracycline resistance in a number of staphylococcal strains was investigated. The strains examined could be classified into three groups: (i) those possessing a high basal level of resistance and in which resistance could be induced to higher levels (macro-inducible); (ii) those which had a high uninduced level of resistance, but which were virtually uninducible (macro-constitutive); (iii) one derivative which had a low basal level of resistance and was also uninducible (micro-constitutive). Resistance in macro-constitutive strains was plasmid mediated and typical of organisms possessing wild-type plasmids. The macro-constitutive pattern of resistance appeared to be correlated with a chromosomal location for the resistance genes, whereas the micro-constitutive pattern was correlated with loss of a region from the wild-type plasmid. Analysis of membrane proteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis suggested that a number of membrane polypeptides became unstable in staphylococci possessing high-level tetracycline resistance. In particular, the absence of a polypeptide of 22,000 daltons was always associated with high-level resistance. There was no evidence that multiple gene copies are required for expression of tetracycline resistance in
Staphylococcus aureus
.
Polyene-Resistant Mutants of
Aspergillus fennelliae
: Identification of Sterols
Authors: Kim S. J. , Kwon-Chung K. J. , Milne G. W. A. , Prescott B.
Published: June 2012

Four mutants strains of
Aspergillus fennelliae
resistant to various polyene antibiotics have been analyzed for their sterol content. The mutant strains contained Δ
7,22,24(28)
-ergostatrien-3β-o1 and Δ
7,22
-ergostadien-3β-o1 as the major sterols, whereas the wild types contained ergosterol, indicating that the mutants contain metabolic blocks for C
5
−C
6
dehydrogenation and C
24
−C
28
reduction in the biosynthesis of ergosterol. Revertant sectors arising from the mutant colonies contained either more Δ
7,22
-ergostadien-3β-o1 than the parent mutant strain or showed the reappearance of ergosterol. The revertant sectors also showed lower resistance to amphotericin B and a higher rate of sporulation than the parent mutant strain. These results confirm our previous observations that the presence of ergosterol is directly related to the drug susceptibility and the normal rate of sporulation in this species.
Binding of Aminoglycosides to Feces
Authors: Wagman Gerald H. , Bailey Janet V. , Weinstein Marvin J.
Published: June 2012

Gentamicin and several other basic antibiotics were examined for their ability to adsorb to dog feces. It was found that 44 to 90% of all antibiotics studied were adsorbed to feces depending on the ratio of antibiotic to fecal material. Attempts to extract these antibiotics by acid treatment after adsorption onto feces were only partially successful since large portions of the bound materials were not removed.
Primaquine Diphosphate: Inhibition of Newcastle Disease Virus Replication
Authors: Burdick John R. , Durand D. P.
Published: June 2012

The response of Newcastle disease virus replication to primaquine, an antimalarial drug, was examined in chicken embryo cells (CEC). Virus-induced hemadsorption was completely inhibited by 250 μg of primaquine per ml. At lower concentrations, hemadsorption inhibition was dose dependent. Primaquine retarded virus-induced redistribution of receptor sites on the host cell plasma membrane as shown by the failure of infected, drug-treated CEC to be agglutinated with concanavalin A. The production of infectious progeny virus was substantially inhibited by the addition of primaquine at various times postinfection. When the drug was added early in the virus replication cycle, viral ribonucleic acid (RNA) synthesis was inhibited; however, when the drug was added late in the cycle, stimulation of RNA synthesis was observed. Primaquine was also shown to retard the incorporation of [
14
C]amino acids into proteins of virus-infected CEC. We suggest that the major role of primaquine is inhibition of protein synthesis; this results in changes in: hemadsorption, redistribution of lectin receptors, release of progeny, and virus-induced RNA synthesis.
Synergistic Effect of Combinations of Sulfamethoxazole, Trimethoprim, and Colistin Against
Pseudomonas maltophilia
and
Pseudomonas cepacia
Authors: Nord Carl-Erik , Wadström Torkel , Wretlind Bengt
Published: June 2012

Eighteen strains of
Pseudomonas maltophilia
and eight strains of
P. cepacia
were tested for susceptibility to sulfamethoxazole, trimethoprim, and colistin in different combinations. A synergistic effect was found against most of the strains.
Paper Disk-Agar Diffusion Assay of Penicillin in the Presence of Streptomycin
Authors: Raahave Dennis
Published: June 2012

Microbiological assay of individual antibiotics in mixtures of antibiotics depends on the use of selective inactivation and/or of test bacteria with differential susceptibility. Controlled experiments revealed that streptomycin in concentrations of 20 and 40 μg/ml did not influence a disk diffusion assay of penicillin with
Sarcina lutea
(ATCC 9341) as the test organism. In the case of penicillin concentrations less than or equal to 1 IU/ml, addition of 80 μg of streptomycin per ml influenced the penicillin assay significantly. Clinical use of streptomycin resulting in levels above 40 μg/ml usually did not occur; therefore penicillin could be assayed as though streptomycin were not present. We observed additionally that
S. lutea
was unable to grow on agar plates prepared with semicarbazide hydrochloride.
Beta-Lactamase Activity in Ampicillin-Resistant
Haemophilus influenzae
Authors: Farrar W. Edmund , O'Dell Noel M.
Published: June 2012

The specific activity, substrate profile, response to inhibitors, inducibility, and cellular localization of the beta-lactamase produced by an ampicillin-resistant strain of
Haemophilus influenzae
type B were investigated. In these properties the enzyme resembles β-lactamases produced by other gram-negative bacilli more closely than those produced by gram-positive organisms. It is quite similar to an enzyme found in strains of
Klebsiella pneumoniae
, and differs significantly from those described in other gram-negative bacilli. Comparison of the substrate profile with the minimal inhibitory concentrations of various β-lactamase antibiotics suggests that the β-lactamase plays an important role in the antibiotic resistance of this organism.
Antibacterial Effects of Silver Electrodes with Weak Direct Current
Authors: Spadaro J. A. , Berger T. J. , Barranco S. D. , Chapin S. E. , Becker R. O.
Published: June 2012

Silver, platinum, gold, stainless-steel, and copper electrodes were used with low currents (0.02 to 20 μA/mm
2
) to explore their electrochemical effects on the growth of four bacterial species. In the higher current ranges, all electrodes inhibited growth at both poles, usually in conjunction with electrolytic break-down of the medium and severe corrosion of the metal. Silver, however, was extremely bacteriostatic, even at the lowest current, when used as the anode. Quantitative studies showed that most of this inhibition takes place in a few hours and is not accompanied by changes in pH. Electrochemically injected silver from the anode is probably the instrumental agent, being effective in concentrations of about 5 μg/ml. This is the equivalent concentration of silver sulfadiazine that has been shown to give complete inhibition of bacteria, but without the sulfonamide moiety.
Studies on the Absorption, Distribution, Metabolism, and Excretion of Propionylmaridomycin in Rats
Authors: Matsuzawa Tai , Kondo Takao , Kita Yasuo
Published: June 2012

The absorption, distribution, metabolism, and excretion of propionylmaridomycin was investigated in the rat by using [
14
C]propionylmaridomycin. Propionylmaridomycin was absorbed from the gastrointestinal tract at a relatively rapid rate and was readily distributed into tissues. Among the tissues examined, liver, kidney, and lung showed a remarkably higher level of the radioactivity than plasma, while distribution of the radioactivity into brain was little. However, a significant accumulation of the radioactivity in tissues was not observed. Excretion of the radioactivity was mainly via the fecal route and the high fecal recovery was accounted for by unabsorbed drug and biliary excretion of the drug and/or its metabolites. Tissue distribution of antimicrobial activity was also investigated and lung was found to show the highest antimicrobial activity among any tissues examined. Propionylmaridomycin was completely converted to several metabolites by the rat and the presence of at least three components was confirmed as biologically active metabolites. Of these metabolites, 4″-depropionyl-9-propionylmaridomycin was identified, which was the major metabolite in tissues, plasma, and urine.
Effects of Sublethal Concentrations of Benzylpenicillin on
Pseudomonas aeruginosa
Authors: Nordström Kurt , Sykes Richard B.
Published: June 2012

Pseudomonas aeruginosa
produces a low basal level of β-lactamase (0.002 to 0.004 IU/mg of protein when benzylpenicillin is used as substrate). The β-lactamase specific activity can be increased several hundredfold by growing the bacteria in the presence of β-lactam antibiotics. This induction was studied in
Pseudomonas aeruginosa
1822s. The single-cell resistance to benzylpenicillin was 750 μg/ml. In liquid culture all concentrations of benzylpenicillin tested (25 to 2,000 μg/ml) affected the bacteria similarly: β-lactamase formation was induced, the cells became cholate sensitive, growth rate decreased, filaments were formed, and β-lactamase was excreted. The effect appeared earlier the higher the concentration of the antibiotic. Most of the effects obtained are concerned with the functioning of the outer membrane. The excretion of β-lactamase seems to be due to an opening of the periplasmic volume rather than to lysis of the cells. Carbenicillin gave the same effects as benzylpenicillin at the same concentrations; the 10-fold lower resistance to carbenicillin than to benzylpenicillin can be explained by the inability of the inducible β-lactamase to hydrolyze carbenicillin. The induced β-lactamase was first cell bound and to a great extent located in the periplasmic volume, but later it was excreted into the medium. This extracellular activity was responsible for the detoxification of the medium. This is analogous to the behavior of gram-positive bacteria rather than to that of
Enterobacteriaceae
.
Characteristics of the In Vitro Inhibition of Arenavirus Synthesis by Bis-Benzimidazoles
Authors: Stella J. P. , Yankaskas K. D. , Morgan J. H. , Fox M. P. , Pfau C. J.
Published: June 2012

The dihydrochloride salt of (
S,S
)-1,2-bis(5-methoxy-2-benzimidazolyl)-1,2-ethandiol (A37536) inhibits the synthesis of lymphocytic choriomeningitis (LCM), Parana, and Pichinde viruses in L-929 cells. The compound has no direct inactivating effect on LCM virus nor does it affect the adsorption of LCM virus to L cells. The drug-cell interaction is slow. Maximal activity is observed only by exposing cells to the drug at least 8 h prior to LCM virus infection, or by concomitant drug treatment and infection at a low multiplicity. Addition of serum-free media to L cells after LCM virus infection diminishes the activity of A37536. Whereas A37536 exhibits its antiviral activity at concentrations that have little or no effect on L cell division rate, a marked change can be noted in the cell's sensitivity to lysis by standard trypsin dispersal procedures. A37536 has no specific antiviral activity in LCM virus-infected BHK, HeLa, or Vero cells. All of the four tested derivatives of A37536 showed antiviral activity against LCM virus but only at concentrations that reduced the growth rate or were toxic to L cells.
Rapid, Precise, Turbidometric Assay for Low Levels of Ampicillin in Serum After Single-Dose Oral Administration
Authors: Whyatt Philip L. , Dann Raymond E. , Slywka Gerald W. A. , Meyer Marvin C.
Published: June 2012

A turbidometric assay is described for the quantitative measurement of ampicillin in serum. Standard curves prepared with known concentrations of ampicillin in serum exhibited acceptable linearity over a concentration range of approximately 0.2 to 1.8 μg/ml. Data are presented to show the excellent precision of the assay and the application of the assay to clinical studies. The advantages of this method over other procedures are discussed. Because of the questionable stability of ampicillin, samples containing known concentrations of ampicillin in serum were assayed after storage for various lengths of time. Serum samples maintained in the frozen state until the time of assay exhibited approximately 12% degradation after 7 days, whereas those samples which were subjected to repeated thawing and refreezing exhibited approximately 25% degradation after the same time interval.
Simple Assay for Clindamycin in the Presence of Aminoglycosides
Authors: Ervin F. Richard , Bullock Ward E.
Published: June 2012

The presence of aminoglycoside antibiotics interferes with the determination of clindamycin levels by standard microbiological assay. A new bioassay method of quantitation of clindamycin in the presence of aminoglycosides is presented. This technique is based on the fact that incorporation of calcium chloride into assay agar blocks the antimicrobial activity of aminoglycosides against
Sarcina lutea
but allows the assay of as little as 0.31 μg of clindamycin per ml. The error of the system is less than 10%. This method is simple and adaptable to existing assay systems for clindamycin.
Simple Technique for the Assay of Antibiotic Synergism Against Enterococci
Authors: Lee Wie-Shing , Komarmy Louis
Published: June 2012

A simple technique with antibiotic-impregnated disks has been developed to demonstrate the antibiotic synergism of penicillins and aminoglycosides against enterococci. The two antibiotic disks are placed on inoculated plates so that the distance between their centers is less than the sum of the two radii of their previously determined inhibitory zones. After 5 h of incubation, β-lactamase powder is dusted onto the susceptibility plate with a sterile cotton swab. After overnight incubation, the synergistic effect of the antibiotics is demonstrated by a clear area of no growth in between the two disks. There is good correlation between the synergism determined by this procedure and the susceptibility of the organisms to 2 mg of streptomycin per ml. This technique is simple and can be employed by any laboratory which performs Kirby-Bauer susceptibility procedures.
Acute Pelvic Inflammatory Disease and Clinical Response to Parenteral Doxycycline
Authors: Chow Anthony W. , Malkasian Kay L. , Marshall John R. , Guze Lucien B.
Published: June 2012

The bacteriology of acute pelvic inflammatory disease (PID) and clinical response to parenteral doxycycline were evaluated in 30 patients. Only 3 of 21 cul-de-sac cultures from PID patients were sterile, whereas all 8 normal control subjects yielded negative results (
P
< 0.005). Poor correlation was observed between cervical and cul-de-sac cultures.
Neisseria gonorrhoeae
, isolated from the cervix in 17 patients (57%), was recovered from the cul-de-sac only once.
Streptococcus, Peptococcus, Peptostreptococcus
, coliforms, and other organisms normally present in the vagina were the predominant isolates recovered from the cul-de-sac. Parenteral doxycycline resulted in rapid resolution of signs and symptoms (within 48 h) in 20 of 27 evaluable patients (74%). In five others, signs and symptoms of infection abated within 4 days. The remaining two patients failed to respond; in both cases, adnexal masses developed during doxycycline therapy. Gonococci were eradicated from the cervix in all but one patient who, nevertheless, had a rapid defervescence of symptoms. There was no clear-cut correlation between the clinical response and in vitro susceptibility of cul-de-sac isolates to doxycycline. These data confirm the usefulness of broad-spectrum antibiotics in acute PID. Culdocentesis is a reliable means of obtaining material for the bacteriological diagnosis of acute PID; however, the pathogenetic role and relative importance of gonococci and various other bacteria in acute PID need to be clarified further.
Simplified Medium for Ampicillin Susceptibility Testing of
Haemophilus influenzae
Authors: Jorgensen James H. , Jones Pamela M.
Published: June 2012

Recent reports of bona fide ampicillin resistance among strains of
Haemophilus influenzae
have emphasized the need for improved methods of susceptibility testing of clinical isolates. A simplified medium composed of only Mueller-Hinton medium plus supplement C (yeast autolysate and hematin) was used successfully for ampicillin susceptibility testing of 20 recent clinical isolates of
H. influenzae
, including six strains with confirmed ampicillin resistance. With this medium, susceptible strains were inhibited by less than 1 μg of ampicillin per ml, whereas resistant strains had minimal inhibitory concentrations of 8 μg or greater per ml. This medium can be used for either disk diffusion, tube dilution, or agar plate dilution methods of susceptibility testing. It has the practical advantage of simplicity of preparation and retains the light color and transparency of Mueller-Hinton medium. This medium can also be used for preparation of an inoculum suspension that can be adjusted to a standardized turbidity.
Antibiogram and Lipid Analysis of a Pigmented Strain of
Serratia marcescens
and Its Nonpigmented Variants
Authors: Button Gary L. , Miller Marcia A. , Tsang Joseph C.
Published: June 2012

Antibiograms and lipid analyses of
Serratia marcescens
pigmented strain 08 and its nonpigmented variants are compared. The overall lack of significant differences between pigmented and nonpigmented strains suggests that the role of pigment formation may not be related to antibiotic susceptibility.
Rifampin Disks in Mycobacterial Susceptibility Testing
Authors: Griffith Marguerite , Schifferle Dolores , Midura Thaddeus , Wood Ronald M.
Published: June 2012

A comparison of rifampin susceptibility test results on 407 strains of mycobacteria using conventional medium in parallel with disk medium showed good agreement. Techniques are described for utilization of drug-impregnated disks in the preparation of medium and for a quality control screening procedure for disks.
Antimicrobial Agents from Marine Algae
Authors: Sims James J. , Donnell Mark S. , Leary John V. , Lacy George H.
Published: June 2012

The antimicrobial activity of five compounds extracted from marine algae was tested against
Staphylococcus aureus, Salmonella choleraesuis, Mycobacterium smegmatis, Candida albicans
, and
Escherichia coli
. Three of the compounds, cycloeudesmol, laurinterol, and debromolaurinterol, exhibited activity at concentrations approaching that of streptomycin. None of the compounds inhibited all of the organisms tested. There appeared to be selectivity for gram-positive microbes.
In Vitro Activity of Penicillins Against Anaerobes
Authors: Tally Francis P. , Jacobus Nilda V. , Bartlett John G. , Gorbach Sherwood L.
Published: June 2012

The in vitro susceptibility of 162 anaerobic isolates from clinical material were tested to pencillin G, BL-P1654, and carbenicillin. Penicillin G and BL-P1654 showed good activity against
Bacteroides fragilis
, but only 60% of strains were susceptible to carbenicillin at achievable blood levels (128 μg/ml).
In Vitro Evaluation of a New Quinolone Antibacterial
Authors: Stilwell Gregory , Holmes King , Turck Marvin
Published: June 2012

The activity of R-802, a quinolone antibacterial agent, was studied in vitro and found to be active against
Enterobacteriaceae
; less than 4 μg of drug per ml was required to inhibit most isolates. The majority of
Pseudomonas aeruginosa
grew in a concentration of 256 μg of R-802 per ml when studied in broth against an inoculum of 10
8
organisms per ml.
Antimicrobial Activities of 81.723 hfu, a New Pleuromutilin Derivative
Authors: Drews Jürgen , Georgopoulos Apostolos , Laber Georg , Schütze Eberhard , Unger Judith
Published: June 2012

The new pleuromutilin derivative 81.723 hfu is extremely active against gram-positive organisms such as streptococci, staphylococci, and against mycoplasmas. A number of
Shigella, Klebsiella
, and
Escherichia coli
strains were also found to be quite susceptible to this new agent, whereas other gram-negative organisms like
Pseudomonas aeruginosa, Proteus
species, and
Alcaligenes faecalis
proved to be naturally resistant to 81.723 hfu. The new compound acts bacteriostatically. Bactericidal effects have been observed only at concentrations which are 100-fold higher than the minimal inhibitory concentrations. The new antibiotic is well tolerated in all animal species tested so far and has been successfully used in the treatment of experimental infections with gram-positive organisms and with mycoplasmas in mice and rats. Resistance against this new compound arose gradually in all microorganisms investigated. It is noteworthy that the rate at which resistance against 81.723 hfu emerged in mycoplasmas (
Mycoplasma gallisepticum
and
Mycoplasma hyorhinis
) was significantly slower than the corresponding rate at which resistance against tylosin tartrate appeared. Mycoplasma strains which became insensitive to 81.723 hfu were also resistant to tylosin tartrate, whereas mycoplasmas which developed resistance against tylosin tartrate, although less sensitive to 81.723 hfu than wild-type strains, were still eliminated by this drug. In a strain of
Klebsiella pneumoniae
, complete cross-resistance was observed between the pleuromutilin derivative on one hand and lincomycin and erythromycin on the other. Modest degrees of cross-resistance were also observed with chloramphenicol. However, it appears unlikely that the latter phenomenon is sufficiently pronounced to affect treatment with either antibiotic.
Studies of Cephalothin: Aminoglycoside Synergism Against Enterococci
Authors: Weinstein Allan J. , Moellering Robert C.
Published: June 2012

Combinations of cephalothin and aminoglycoside antibiotics are not currently used in the therapy of serious enterococcal infections, because clinical trials of these combinations have been unsuccessful. Studies of 28 enterococci isolated from patients with enterococcal bacteremia suggested three possible mechanisms for this in vivo antibiotic failure: (i) a relatively high level of resistance to cephalothin among all enterococci and especially those characterized as
Streptococcus faecium
, (ii) a significant incidence of high-level resistance to the aminoglycosides among certain strains of enterococci, and (iii) a failure of synergism to occur when cephalothin concentrations fall below the minimal inhibitory concentration of the enterococcus, as occurs during the in vivo metabolism and excretion of this antibiotic when given in standard doses for endocarditis.
Recovery of Polysome Function of T4-Infected
Escherichia coli
After Brief Treatment with Chloramphenicol and Rifampin
Authors: Green C. E. , Cameron H. J. , Julian G. R.
Published: June 2012

T4-infected
Escherichia coli
cells briefly exposed to rifampin, or to rifampin plus chloramphenicol, were capable of protein synthesis for some time after removal of the antibiotics, although ribonucleic acid synthesis was irreversibly inhibited. Partially completed peptides trapped on polysomes by high levels of chloramphenicol were eventually completed after removal of the drug, as demonstrated by subjecting labeled peptides from appropriate polysome regions to polyacrylamide disc gel electrophoresis. Thus, the effect of the drug appears to be reversible on the molecular as well as the cellular level.
Penicillin-Resistant Mechanisms in
Pseudomonas aeruginosa
: Binding of Penicillin to
Pseudomonas aeruginosa
KM 338
Authors: Suginaka Hidekazu , Ichikawa Akira , Kotani Shozo
Published: June 2012

A comparison of the binding of radioactive penicillin G to whole cells and the membrane fraction derived from
Pseudomonas aeruginosa
KM 338 was made. This organism has intrinsic resistance to penicillin. The binding to the membrane fraction which catalyzed peptidoglycan synthesis followed saturation type kinetics and saturation was achieved at approximately 2 nmol of penicillin G per ml, whereas binding to the whole cells was entirely of the nonsaturation type. The binding of carbenicillin to the membrane fraction was determined by competition between radioactive penicillin G and unlabeled carbenicillin for the binding sites. It was bound at the same sites in almost the same manner. When whole cells were pretreated with high concentration of unlabeled penicillin G or carbenicillin, the subsequent binding of radioactive penicillin G to the membrane fraction from carbenicillin-treated cells was entirely nonspecific, but with penicillin G-pretreated cells it was still specific. There was apparently specific binding of radioactive penicillin G to ethylenediaminetetraacetate-treated cells.
P. aeruginosa
KM 338 had an extremely low activity of β-lactamase compared with other enzyme-producing organisms. This enzyme from
P. aeruginosa
KM 338 was of the cephalosporinase type. These data indicate that penicillin resistance of
P. aeruginosa
KM 338 may be a consequence of the development of a permeability barrier which prevents the antibiotic from reaching its sites of action in the cytoplasmic membrane.
Efficacy of Combined Furazolidone and Neomycin in the Control of Contamination in
Leptospira
Cultures
Authors: Myers Donald M.
Published: June 2012

The in vitro effectiveness of furazolidone combined with neomycin for the control of contaminants in
Leptospira
cultures was investigated. Enhanced additive or synergistic bactericidal activity was apparent with the combination when it was compared with each agent used separately or when compared with 5-fluorouracil. Combined furazolidone and neomycin, at 5-μg/ml concentrations each in Fletcher medium or in implanted sensitivity disks of 50 μg and 10 μg, respectively, was effective in inhibiting contaminants and did not interfere with the growth of leptospira belonging to 66 leptospiral collection serotypes. A simple technique for decontaminating swine kidneys from an abattoir for cultural isolation of leptospiras is described. The method involves exposing renal tissue diluted in saline containing furazolidone and neomycin in combination (each in a concentration of 25 μg/ml) for 1 h prior to inoculating culture media. The method is suitable for routine use in the isolation of leptospiras from contaminated clinical or pathological specimens.
Treatment of Anaerobic Infections with Metronidazole
Authors: Tally Francis P. , Sutter Vera L. , Finegold Sydney M.
Published: June 2012

The results of treatment of 10 patients with anaerobic infections with metronidazole are presented. Six patients were cured, three showed initial good response but circumstances required a change to another drug, and one patient did not respond. The unique spectrum of the drug, its pharmacology, and limitations are discussed. The results indicate that further clinical trials to determine the efficacy of metronidazole in the treatment of anerobic infections are indicated.
Comparison of Tetracycline and Minocycline Transport in
Escherichia Coli
Authors: Bene Victor E. Del , Rogers Mary
Published: June 2012

Differences between minocycline and tetracycline transport were demonstrated in an
Escherichia coli
strain with and without an R factor (R46) which confers moderate Tc resistance. Minocycline uptake was similar in R
+
and R
−
organisms, whereas tetracycline uptake was decreased in the R
+
as compared to the R
−
organism. Sodium azide had little effect on tetracycline uptake by either strain but minocycline uptake was completely inhibited by azide.
p
-Chloromercuribenzoate greatly decreased tetracycline uptake in both strains while minocycline uptake was markedly augmented. Both minocycline and tetracycline were effective inducers of decreased tetracycline transport, but only tetracycline had an effect on minocycline uptake. Mutual inhibition of uptake of one antibiotic by the other could not be demonstrated. These studies indicate different mechanisms of transport of minocycline and tetracycline in
E. coli
.
In Vitro Additive Effect of Polymyxin B and Rifampin Against
Serratia marcescens
Authors: Traub Walter H. , Kleber Ingrid
Published: June 2012

The combination of polymyxin B and rifampin resulted in an additive effect against all 12 clinical isolates of
Serratia marcescens
examined, including multiple-drug-resistant isolates.