bluuebunny/crossref_metadata_2025 huggingface dataset:
Activity of metronidazole and its hydroxy and acid metabolites against clinical isolates of anaerobic bacteria
Authors: O'Keefe J P , Troc K A , Thompson K D
Published: June 2012

Susceptibility of clinical isolates of anaerobic bacteria to metronidazole and its two oxidation products, 1-(2-hydroxyethyl)-2-hydroxymethyl-5-nitroimidazole (the "alcohol" metabolite) and 2-methyl-5-nitroimidazole-1-acetic acid (the "acid" metabolite), were determined by the agar dilution technique. Results disclosed that the alcohol metabolite, although less active than metronidazole, inhibited the organisms tested at levels considered susceptible for metronidazole. The acid metabolite was less active, not inhibiting the organisms at levels within the susceptible range. In other studies, mixtures of known concentrations of metronidazole and the metabolites were assayed in a bioassay system used to measure metronidazole levels. These studies showed that the bioassay will measure metronidazole or the alcohol metabolite; the acid metabolite is not measured at levels achieved in clinical specimens. Since the activity of the alcohol metabolite is comparable to that of metronidazole, we feel that microbiological assays can be used for therapeutic monitoring of metronidazole levels in clinical situations.
Antibacterial activity of mupirocin (pseudomonic acid), a new antibiotic for topical use
Authors: Sutherland R , Boon R J , Griffin K E , Masters P J , Slocombe B , White A R
Published: June 2012

Mupirocin (pseudomonic acid A), an antibiotic produced by Pseudomonas fluorescens, showed a high level of activity against staphylococci and streptococci and against certain gram-negative bacteria, including Haemophilus influenzae and Neisseria gonorrhoeae, but was much less active against most gram-negative bacilli an anaerobes. Nearly all clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis, including multiply resistant strains, were susceptible (mupirocin MIC, less than or equal to 0.5 microgram/ml). There was no cross-resistance between mupirocin and clinically available antibiotics, and the selection of resistant variants in vitro occurred at a low frequency. Mupirocin was highly bound (95% bound) to the protein of human serum, and activity was reduced 10- to 20-fold in the presence of human serum. The activity of mupirocin was not greatly influenced by inoculum size but was significantly enhanced in acid medium. In tests of bactericidal activity, MBCs were 8- to 32-fold higher than MICs and the antibiotic demonstrated a slow bactericidal action in time-kill tests, resulting in 90 to 99% killing after 24 h at 37 degrees C.
In vitro activity of cefbuperazone and other antimicrobial agents against isolates from the female genital tract
Authors: Ohm-Smith M J , Sweet R L , Hadley W K
Published: June 2012

Cefbuperazone (BMY 25182), a new cephamycin, showed activity similar to those of moxalactam and other cephalosporin-cephamycins against aerobic and anaerobic bacteria from female genital tract infections. MICs of the antimicrobial agents were less than or equal to 16 micrograms/ml for greater than 97% of organisms tested. All of the anaerobic bacteria tested were susceptible to clindamycin, metronidazole, and chloramphenicol.
Resistance of Some Species of
Clostridium
to Clindamycin
Authors: Wilkins T. D. , Thiel Teresa
Published: June 2012

Ten strains each of 18 clinically important species of
Clostridium
were tested for susceptibility to clindamycin. Of the 180 strains tested, 56 (31%) were resistant to more than 1.6 μg/ml.
Poly(
N
-Acryloyl-4- and -5-Aminosalicylic Acids II. Antibacterial Properties and Uses for the Preparation of Active, Insoluble Antibiotics
Authors: Kennedy J. F. , Epton J. , Kennedy G. R.
Published: June 2012

The antibacterial properties of poly(
N
-acryloyl-4- and -5-aminosalicylic acids) and their borate complexes were evaluated. Poly(
N
-acryloyl-4- and 5-aminosalicylic acids) were used to render the antibiotics streptomycin and gentamicin insoluble. The antibacterial properties of the resultant water-insoluble streptomycin and gentamicin derivatives were evaluated, and the results show that the polymers are suited to the preparation of active insoluble antibiotics. Potential antimicrobial applications of the polymers are discussed.
In Vitro Activity of 5-Fluorocytosine Against
Candida
and
Torulopsis
Species
Authors: Shadomy S. , Kirchoff Carol B. , Ingroff Ana E.
Published: June 2012

One hundred yeasts were studied. Tests included detailed identification and determination of 24- and 48-hr minimal inhibitory concentrations and minimal fungicidal concentrations of 5-fluorocytosine (5-FC). Final identifications included 57 isolates of
Candida albicans
, 15 isolates of
C. tropicalis
, 13 isolates of
C. parapsilosis
, 7 isolates of
Torulopsis glabrata
, 3 isolates of
C. guilliermondii
, 2 isolates each of
C. stellatoidea
and
Cryptococcus neoformans
, and 1 isolate of
Candida krusei
. Twenty-three original identifications were in error; these involved mostly
C. albicans, C. tropicalis, C. parapsilosis
, and
T. glabrata
. Inhibitory end point readings based on 24 hr of incubation were misleading. Whereas 79 of 91 isolates of
Candida
appeared to be inhibited at 24 hr by 12.5 μg or less of 5-FC/ml, only 52 were inhibited at 48 hr; whereas only 12 isolates appeared to be resistant to 100 μg/ml after 24 hr, 37 were resistant after 48 hr. Susceptibility varied amount the different species.
C. tropicalis
was the most susceptible, with 10 of 15 isolates (66.7%) being inhibited by 12.5 μg or less/ml and 7 (46.7%) being killed by 100 μg or less/ml.
C. albicans
was similarily susceptible; 33 of 57 isolates (57.9%) were inhibited by 12.5 μg or less/ml and 25 (43.9%) were killed by 100 μg or less/ml.
C. parapsilosis
was quite resistant, as only 4 of 13 isolates (30.8%) were inhibited by 12.5 μg or less/ml and 3 (23.1%) were killed by 100 μg or less/ml.
Chloramphenicol Acetyltransferases Specified by
fi
−
R Factors
Authors: Foster T. J. , Shaw W. V.
Published: June 2012

Chloramphenicol acetyltransferases specified by
fi
−
(F fertility-noninhibiting) R factors were compared with those specified by the
fi
+
R factors R1, 222, and R6-S. Three classes of enzyme were distinguished: class I was determined by group N
fi
−
R factors and was indistinguishable from the enzyme determined by
fi
+
R factors, class II was correlated with group W
fi
−
R factors, and class III was determined by R387, an unclassified
fi
−
R factor.
Effect of Elevated Atmospheric Pressure on Penicillin Binding by
Staphylococcus aureus
and
Streptococcus pyogenes
Authors: Schlamm N. A. , Daily O. P.
Published: June 2012

A gas pressure of 68 atm, elicited by helium-oxygen gas mixtures, reduced the susceptibility to penicillin of
Staphylococcus aureus
but not of
Streptococcus pyogenes
. The elevated pressure also caused a reduction in the binding of
14
C-penicillin to
S. aureus
, but not to
S. pyogenes
. When these studies were extended to glycine incorporation, it was shown that, even without penicillin, pressurization reduced glycine incorporation into the cell wall of
S. aureus
. Incorporation into other cellular components was not altered by pressurization. Cells grown in a pressurized environment were slightly more susceptible than those grown at 1 atm to rapid change in osmotic pressure. In the presence of penicillin, glycine incorporation into the cell wall was reduced to the same low level at 68 atm and at 1 atm. These results suggest that pressurization renders
S. aureus
less susceptible to penicillin because it reduces the enzymatic activity of the binding component on the cell, a penicillin-sensitive transpeptidase.
Study of Antibacterial Activity and Bacteriology of Latex from
Asclepias syriaca
L
Authors: McCay Steven , Mahlberg Paul
Published: June 2012

Whole and fractionated latex of
Asclepias syriaca
was tested for antimicrobial or growth-promoting activity with 16 genera and species of bacteria. Latex and extracted fractions (distilled water, acetic acid, sodium bicarbonate, sulfuric acid, and ethyl ether) possessed no detectable antimicrobial activity. Comparison of growth curves of selected bacteria incubated with serum and rubber fractions, as well as controls, revealed no detectable inhibition of growth, except for a slight inhibitory response to autoclaved serum. Most bacteria were capable of utilizing latex for a substrate as indicated by the increased growth rate in the exponential phase. The stationary phase was entered simultaneously by both the treated cultures and the controls. Various bacteria cultured in a litmus latex mixture yielded populations which ranged from <10
4
organisms/ml for
Lactobacillus casei, Staphylococcus aureus
and
Micrococcus lysodeikticus
to 1.1 × 10
10
organisms/ml for
Clostridium acetobutylicum
. Whole latex, as well as the serum and rubber fractions, support the growth of various bacteria, but under field conditions there is no evidence for systemic infection of this type of cell by bacteria.
Two Enzymes Which Phosphorylate Neomycin and Kanamycin in
Escherichia coli
Strains Carrying R Factors
Authors: Brzezinska M. , Davies J.
Published: June 2012

Two enzymes which phosphorylate neomycin and kanamycin have been detected in
Escherichia coli
strains carrying R factors. Neomycin-kanamycin phosphotransferase I can phosphorylate neomycin and kanamycin, but not butirosin. Neomycin-kanamycin phosphotransferase II can phosphorylate all three antibiotics. The enzymes also differ in their response to certain inhibitors of phosphorylation. Neomycin-kanamycin phosphotransferase II is found in certain strains of
Pseudomonas aeruginosa
.
Comparison of the Chemotherapeutic and Pharmacodynamic Activities of Cephradine, Cephalothin, and Cephaloridine in Mice
Authors: Miraglia Gennaro J. , Renz Kathleen J. , Gadebusch Hans H.
Published: June 2012

Cephradine, a new semisynthetic cephalosporin derivative, is 7[
d
(−)-2-amino-2-(1,4-cyclohexadien-1-yl) acetamido]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid hydrate. The compound has a broad spectrum of antimicrobial activity in vitro. When given subcutaneously to mice, cephradine was appreciably more effective than cephalothin against infections induced by penicillinase-producing
Staphylococcus, Escherichia coli, Klebsiella pneumoniae
, or
Enterobacter cloacae
strains. Cephradine and cephaloridine possessed equivalent activity in treating infections caused by these same three gram-negative bacteria. The mean total bioactivity of cephradine in the serum of mice peaked within 30 min (59 μg/ml) after parenteral administration and was approximately threefold that of cephalothin (20 μg/ml), but less than that of cephaloridine (83 μg/ml). Nearly all of the administered cephradine (84%) and cephaloridine (70%) were excreted in the urine as the parent compounds. In contrast, only 47% (total bioactivity) of administered cephalothin was recovered, an amount that represented only 15 to 20% of the parent substance.
Comparison of Gentamicin, Carbenicillin and Gentamicin, and Carbenicillin in
Pseudomonas
Sepsis in Monkeys
Authors: Saslaw Samuel , Carlisle Harold N. , Moheimani Mohammad
Published: June 2012

Intravenous inoculation of 6.0 × 10
10
Pseudomonas aeruginosa
organisms into rhesus monkeys 4 days after intratracheal inoculation of 2.5 mg of vincristine sulfate resulted in fatal sepsis in all of three untreated control monkeys. After intramuscular administration of either 2.5 mg of gentamicin or 50 mg of carbenicillin per kg per day, three of four monkeys in each group survived. When both antibiotics were given at the same dose but in separate sites, six of eight monkeys survived. Antibacterial activity of serum from infected monkeys or normal monkeys was not appreciably different when the two antibiotics were combined. Under the conditions of this study, there was no apparent difference in response of monkeys treated either with gentamicin or carbenicillin alone or with the combination of the two antibiotics.
Trial of the Antiviral Action of Isoprinosine Against Rhinovirus Infection of Volunteers
Authors: Soto A. J. , Hall T. S. , Reed Sylvia E.
Published: June 2012

Isoprinosine (NPT-10381) was given orally to a group of 22 volunteers at a daily dose of 6 g for 7 days; a control group of 23 volunteers received placebo. Volunteers were inoculated intranasally with both rhinovirus type 9 and rhinovirus type 31, and the clinical picture, extent of virus shedding, and serological responses were assessed. There was no evidence that the compound had useful antiviral activity under the conditions of this trial.
Effect of Rifampin on the Immune Response in Guinea Pigs
Authors: Dajani Basem M. , Kasik John E. , Thompson John S.
Published: June 2012

The effect of an oral dose of 20 mg of rifampin per kg per day on the immune response to killed
Mycobacterium bovis
var. BCG, 1-chloro-2,4-dinitrobenzene (DNCB), and sheep red blood cells (SRBC) was studied in adult female guinea pigs. Fully established cutaneous reactions to BCG or DNCB were markedly reduced during rifampin treatment but reverted to pretreatment levels after the drug was discontinued. When treatment was begun 7 days after immunization, positive reactions did not occur during drug administration but developed after cessation. When treatment was initiated 7 days before immunization, the response to these agents was completely suppressed during but also after rifampin was discontinued, suggesting that recognition and processing of the immunogens had been impaired. Rifampin had no effect on the secondary response to SRBC. When treatment was initiated either 7 days before or 2, 3, or 4 days after SRBC immunization, the primary response was abolished, but the reaction to a booster after drug withdrawal varied: some animals developed a normal secondary hemagglutinin response, but the majority reacted as if they had not been previously immunized. These studies indicate that rifampin is an active immunosuppressive agent in the guinea pig.
Experimental Urinary Tract Infection in Rats Caused by
Candida albicans
Authors: Miraglia Gennaro J. , Renz Kathleen J.
Published: June 2012

The increased clinical use of broad-spectrum antibiotics, immunosuppressives, and anti-inflammatory agents is thought to have contributed to the increased incidence of renal infections due to
Candida albicans
. To aid in the search for improved anticandidal agents, we developed an experimental model in which
C. albicans
is injected into the medulla of the surgically exposed kidney of the rat. The ensuing infection is restricted to the urinary tract and can be treated successfully with amphotericin B. This model promises to be of merit in the evaluation of agents potentially useful in treating candidiasis of the urinary tract.
Synergism of Polymyxin and Sulfonamides in L-forms of
Staphylococcus aureus
and
Proteus mirabilis
Authors: Montgomerie J. Z. , Kalmanson G. M. , Guze L. B.
Published: June 2012

Earlier workers suggested that synergism of polymyxin and sulfonamides occurred because sulfonamides produced changes in the cell wall which permitted the more ready access of polymyxin. We tested this hypothesis by using L-forms, which lack cell wall. The demonstration that synergism of polymyxin and sulfonamides occurs in L-forms of
Proteus mirabilis
and
Staphylococcus aureus
suggested that the synergism is a result of some mechanism other than alterations of the cell wall.
Failure of 1-β-
d
-Ribofuranosyl-1,2,4-Triazole-3-Carboxamide (Virazole, ICN 1229) to Stimulate Interferon
Authors: Allen Lois B. , Huffman John H. , Sidwell Robert W.
Published: June 2012

In cultured cells, Virazole failed to stimulate either interferon or a cellular resistance which continued in its absence. Serum from Virazole-treated mice likewise contained no demonstrable interferon.
Potentiation of 5-Fluorouracil, Chromomycin A3, and Bleomycin by Amphotericin B or Polymyxin B in Transformed Fibroblastic Cells
Authors: Kuwano Michihiko , Kamiya Tomoya , Endo Hideya , Komiyama Sotaro
Published: June 2012

By using cultured, transformed fibroblastic cells, antitumor agents including cytosine arabinoside, thio-tepa, nitrogen mustard
N
-oxide, mitomycin C, chromomycin A3, 5-fluorouracil, daunomycin, vinblastine, vincristine, and bleomycin A2 were screened for the potentiation of their activity by amphotericin B or polymyxin B. Among them, the action of 5-fluorouracil and chromomycin A3 on ribonucleic acid synthesis was potentiated in their action by amphotericin B, not by polymyxin B. Bleomycin A2 was potentiated in its action on deoxyribonucleic acid and ribonucleic acid synthesis only by polymyxin B.
Mechanisms of R Factor R931 and Chromosomal Tetracycline Resistance in
Pseudomonas aeruginosa
Authors: Tseng J. T. , Bryan L. E.
Published: June 2012

The mechanism of tetracycline resistance mediated by R931 (a
Pseudomonas aeruginosa
R factor not yet successfully transferred to
Escherichia coli
recipients) was examined. In strain 931 (R931) (minimal inhibitory concentration [MIC] 200 μg/ml) significant tetracycline uptake did not occur until 100 μg of tetracycline per ml was included in uptake studies. The introduction of R931 into strain 280 resulted in a significant decline in
3
H-tetracycline uptake. In both strains 931 (R931) and 280 (R931), a further reduction in tetracycline uptake resulted from pre-incubation with 1 μg of tetracycline per ml. Tetracycline resistance in R
−
P. aeruginosa
strains 1731, 1885, and 494, considered to be of chromosomal origin, was associated with a lack of tetracycline uptake until the MIC of the strain was obtained. No evidence of tetracycline inactivation or ribosomal resistance was detected in R
−
or R
+
strains. The MIC for R
−
strains was generally about 25 μg/ml and that for R
+
strains was 75 to 200 μg/ml.
Variable Response of Human Cells to Polyinosinic-Polycytidylic Acid
Authors: Sreevalsan T.
Published: June 2012

Human cells derived from various organs of a single embryo responded variably to polyinosinic-polycytidylic acid with respect to induction of antiviral resistance and interferon.
Divalent Cation Reversal of Tetracycline-Inhibited Respiration of
Klebsiella pneumoniae
Authors: Andrews Wallace H. , Magee Lyman A.
Published: June 2012

Magnesium and ferrous compounds reversed tetracycline inhibition of respiration in
Klebsiella pneumoniae
, and the two compounds together had greater reversing ability than either alone.
Uptake of Minocycline and Tetracycline by Tetracycline-Susceptible and -Resistant Bacteria
Authors: Kuck N. A. , Forbes M.
Published: June 2012

Minocycline (7-dimethylamino-6-demethyl-6-deoxytetracycline) is a new semisynthetic tetracycline with potent activity against tetracycline-susceptible bacterial pathogens and unique activity against tetracycline-resistant staphylococci. Studies to determine the basis for this unique activity showed that, whereas tetracycline-resistant staphylococci took up less
3
H-tetracycline than the susceptible cells, both the tetracycline-resistant and -susceptible cells accumulated equivalent amounts of
14
C-minocycline. In contrast, tetracycline-resistant
Escherichia coli
cells were relatively resistant to minocycline and accumulated less of both drugs than did the susceptible organisms. It is proposed that minocycline is effective against tetracycline-resistant staphylococci because of its ability to penetrate the cells sufficiently to reach inhibiting concentrations at sensitive reaction sites.
Comparative Effects of 3-Ethyl-8-Methyl-1,3,8-Triazabicyclo[4,4,0]Decan-2-one and Diethylcarbamazine Against
Litomosoides carinii
in Rodents
Authors: Thompson Paul E. , Zeigler Julianne B. , McCall John W.
Published: June 2012

3-Ethyl-8-methyl-1,3,8-triazabicyclo[4,4,0]decan-2-one and diethylcarbamazine were tested comparatively against
Litomosoides carinii
in Mongolian jirds and cotton rats. The drugs were compared in jirds by oral and by intraperitoneal administration. Comparisons in cotton rats were done by intraperitoneal administration. The drugs were given in a wide range of doses twice daily for 4 consecutive days. Parameters used for judging efficacy included the rate, degree, and duration of microfilaremia suppression as well as effects on adult worms. The two drugs exhibited similar strong but transient effect against microfilariae; neither drug had appreciable effect in killing adult worms.
Axenomycins, New Cestocidal Antibiotics
Authors: Bruna C. Della , Ricciardi M. L. , Sanfilippo A.
Published: June 2012

Axenomycins are a new group of macrolide antibiotics isolated from the fermentation broth of
Streptomyces lisandri
n.sp. They exhibit anthelmintic activity against tapeworms (
Cestoda
). Three different fractions, A, B, and D, have been obtained, the most active fraction being axenomycin D. The activities of the axenomycin complex and axenomycin D against
Hymenolepis nana
in mice,
Taenia pisiformis, Dipylidium caninum
, and
Diphyllobothrium
sp. in dogs, and
Moniezia expansa, M. benedeni
, and
Avitellina centripunctata
in lambs were studied in experimentally and naturally infected animals. Axenomycins were effective and well tolerated by the oral route. Worm reduction rates after a single oral dose were 90 to 100% with 5 to 10 mg of axenomycin D/kg and 50 to 100% with 20 mg of axenomycin complex/kg.
Effects of production of abnormal proteins on the rate of killing of Escherichia coli by streptomycin
Authors: Wyka M A , St John A C
Published: June 2012

The role of abnormal membrane proteins in modulating the rate of killing by streptomycin was investigated. Davis et al. (B.D. Davis, L. Chen, and P.T. Tai, Proc. Natl. Acad. Sci. USA 83:6164-6168, 1986) have proposed that misread membrane proteins created by the action of streptomycin on translating ribosomes cause the formation of nonspecific membrane channels which allow increased uptake of the antibiotic and contribute to its bactericidal action. Pretreatment of Escherichia coli with a low concentration of puromycin enhanced the rate of killing by streptomycin. The effect of the pretreatment with puromycin was transient, since approximately normal rates of killing by streptomycin were restored after 30 min of incubation in antibiotic-free medium. This time period correlates with the time required to degrade labile polypeptides in puromycin-treated cells. The induction of a specific abnormal malE-lacZ fusion protein, which is capable of disrupting the normal membrane protein secretion process, also increased the rate of killing by streptomycin. Induction of malF-phoA fusion proteins, which have no significant effects on membrane integrity, did not alter susceptibility to streptomycin. These observations suggest that certain abnormal membrane proteins can contribute to the bactericidal action of streptomycin.
Renal dehydropeptidase-I stability of LJC 10,627, a new carbapenem antibiotic
Authors: Hikida M , Kawashima K , Nishiki K , Furukawa Y , Nishizawa K , Saito I , Kuwao S
Published: June 2012

LJC 10,627 is a new parenteral carbapenem antibiotic. LJC 10,627 stability against human renal dehydropeptidase-I was compared with that of imipenem. Hydrolysis of this compound was not detectable by spectrophotometrical assay. Even after a 2-h incubation of antibiotics with this enzyme at 30 degrees C, the concentration of LJC 10,627 remained at 92.3% of the initial concentration, whereas imipenem completely disappeared. Thus, it was found that this compound was highly stable against human renal dehydropeptidase-I. Furthermore, LJC 10,627 had a low affinity for this enzyme, as indicated by the high Ki value (0.38 mM).
Expression of antibiotic resistance genes in the integrated cassettes of integrons
Authors: Collis C M , Hall R M
Published: June 2012

Plasmids containing cloned integron fragments which differ only with respect to either the sequence of the promoter(s) or the number and order of inserted cassettes were used to examine the expression of resistance genes encoded in integron-associated gene cassettes. All transcripts detected commenced at the common promoter P(ant), and alterations in the sequence of P(ant) affected the level of resistance expressed by cassette genes. When both P(ant) and the secondary promoter P2 were present, transcription from both promoters was detected. When more than one cassette was present, the position of the cassette in the array influenced the level of antibiotic resistance expressed by the cassette gene. In all cases, the resistance level was highest when the gene was in the first cassette, i.e., closest to P(ant), and was reduced to different extents by the presence of individual upstream cassettes. In Northern (RNA) blots, multiple discrete transcripts originating at P(ant) were detected, and only the longer transcripts contained the distal genes. Together, these data suggest that premature transcription termination occurs within the cassettes. The most abundant transcripts appeared to contain one or more complete cassettes, and is possible that the 59-base elements found at the end of the cassettes (3' to the coding region) not only function as recombination sites but may also function as transcription terminators.
Clinical and Laboratory Evaluation of Amoxicillin (BRL 2333) in the Treatment of Urinary Tract Infections
Authors: Middleton Francis G. , Poretz Donald M. , Duma Richard J.
Published: June 2012

Amoxicillin (α-amino-
p
-hydroxybenzyl penicillin) is a new oral semisynthetic penicillin with antibacterial activity similar to that of ampicillin; however, it is more completely absorbed and urinary concentrations are higher. Twenty-seven patients during 28 episodes of urinary tract infection were treated with oral amoxicillin given either as 250- or 500-mg doses. Clinical cure or improvement occurred in 23 of 27 infections (85%); eradication of the responsible organisms occurred in 23 of 26 infections (88%); and both clinical cure or improvement
and
eradication occurred in 20 of 25 infections (80%). Three infections relapsed. Failure to respond bacteriologically was associated with resistant organisms in two patients and with chronic pyelonephritis (
Proteus mirabilis
) is one. Concentrations of amoxicillin in serum obtained 2 h after administration were more variable than those previously reported for reasons which were obscure. In vitro studies revealed amoxicillin to be comparable to ampicillin when tested against most gram-negative bacilli; however, in this situation amoxicillin may be more effective than ampicillin against enterococci.
5-Fluorocytosine in the Treatment of Experimental Candidiasis in Immunosuppressed Mice
Authors: Linquist Jeanne A. , Rabinovich Sergio , Smith Ian M.
Published: June 2012

A model infection with
Candida albicans
was established in mice. The animals were pretreated for 1 week with azathioprine, given dexamethasone, and then infected intravenously with
Candida
. Mortality for the group given
Candida
infection alone was 20%, 38% when azathioprine was added, and 50% when dexamethasone and azathioprine were given with infection. The titers of
Candida
in most mice were 10
6
per gram of kidney. The rest of the mice were killed at 30 days. At this time, 16% had no evidence of
Candida
in the kidneys, but 40% of the mice had titers of 10
6
or more. Mice treated with 5-fluorocytosine had a mortality of less than 4% in 30 days. Five percent of the treated mice killed at 30 days had titers of
Candida
of 10
6
. Therefore, 5-fluorocytosine increases survival in the presence of continued therapy with azathioprine with or without pretreatment with dexamethasone. The survival is associated with decreased titers of
Candida
in the kidneys.
Antiprotozoal Activity of Rubratoxin B
Authors: Hayes A. Wallace
Published: June 2012

Growth of
Tetrahymena pyriformis
HSM was inhibited by a concentration of 25 μg of rubratoxin B per ml of growth medium. The inhibitory effect of aflatoxin B
1
-rubratoxin B mixtures on growth of
T. pyriformis
was induced by rubratoxin B only. Total cellular deoxyribonucleic acid increased in the presence of 5 μg of rubratoxin B per ml of growth medium, whereas higher concentrations (25 μg/ml of growth medium) were required before a decrease in total protein was observed.
Bactericidal Effect of Combinations of Nalidixic Acid and Various Antibiotics on
Enterobacteriaceae
Authors: Michel J. , Luboshitzky R. , Sacks T.
Published: June 2012

The activity of nalidixic acid combined with each of 10 other antimicrobial agents on 95 strains of
Enterobacteriaceae
was studied. Synergism was found less often than antagonism, and the commonest outcome was indifference. Combinations of nalidixic acid with kanamycin, gentamicin, or colistin were more often synergistic than antagonistic, whereas with the other antibiotics the combination was more often antagonistic than synergistic. Synergistic effects were more common with
Shigella
than with other genera. In vitro examination for synergism or antagonism appears to be advisable before nalidixic acid is used therapeutically in combination with other antimicrobial agents.
In Vitro and In Vivo Activity of Penicillinase Inhibitor KA-107 Against
Staphylococcus aureus
FS-1277
Authors: Ohno H. , Matsumae A. , Iwai Y. , Nakae M. , Ōmura S. , Hata T.
Published: June 2012

The activities of penicillinase inhibitor, KA-107 extracted from culture filtrates of
Streptomyces gedanensis
ATCC 4880, were studied by using penicillin-resistant
S. aureus
FS-1277 and by means of in vitro and in vivo tests.
Transmissible Resistance to Penicillin G, Neomycin, and Chloramphenicol in
Rhizobium japonicum
Authors: Cole Michael A. , Elkan Gerald H.
Published: June 2012

The genetic basis for resistance to a number of antibiotics was examined in
Rhizobium japonicum
. Resistance to penicillin G, neomycin, and chloramphenicol appears to be mediated by an extrachromosomal element similar to that found in the
Enterobacteriaceae
. Resistance to these antibiotics was eliminated from cells by treatment with acridine orange, and resistance to all three antibiotics could be transferred en bloc to
Agrobacterium tumefaciens
under conditions excluding transformation or transduction as possible genetic mechanisms.
Effect of Racephenicol on Antibiotic Resistance of Lactose-Fermenting Enteric Bacteria in Chickens
Authors: Rollins Larry D. , Pocurull Dorothy W. , Reynolds Steven
Published: June 2012

The incidence of lactose-fermenting enteric organisms resistant to chloramphenicol increased from less than 0.1% prior to treatment to more than 90% in two groups of chickens fed racephenicol-supplemented feed at 50 or 140 g/ton for 10 days, whereas controls remained unchanged. A concurrent increase in the incidence of organisms resistant to dihydrostreptomycin, oxytetracycline, ampicillin, and sulfonamides also occurred. Minimum inhibitory concentrations for chloramphenicol increased from <10 μg/ml to >300 μg/ml in most
Escherichia coli
isolates in response to treatment. The observed resistance was transferable to
E. coli
and
Salmonella
.
Effects of Energy Metabolism on the Release of Bound Proflavine from Sensitive and Resistant
Escherichia coli
Authors: Mehta Bipin M. , Gravelle M. Joan , Kushner Donn J.
Published: June 2012

Proflavine inhibited the aerobic and anaerobic utilization of glucose by sensitive but not by resistant
Escherichia coli
. In resistant cells that had bound proflavine, glucose utilization was accompanied by release of the dye. After glucose was used up, the cells could again take up proflavine. If the amount of proflavine bound to sensitive cells was too low to inhibit glucose utilization, adding glucose to these cells caused them to release the dye. With higher proflavine concentrations, inhibitory to glucose utilization, the dye remained cell bound. Thus, metabolic energy causes the release of proflavine by both sensitive and resistant cells. In the former, energy production is inhibited by proflavine, and thus the dye prevents its own release. Chloramphenicol did not interfere with metabolically induced release of proflavine from resistant cells. Cyanide inhibited the glycerol-induced loss of proflavine, but not the glucose-induced loss. Azide and carbonyl cyanide
m
-chlorophenylhydrazone could prevent proflavine release without inhibiting glucose utilization.
In Vitro Activity of Cephalothin and Three Penicillins Against
Escherichia coli
and
Proteus
Species
Authors: Barry Arthur L. , Hoeprich Paul D.
Published: June 2012

The susceptibility of clinical isolates of
Escherichia coli
(67) and
Proteus
species (58) to cephalothin, ampicillin, benzyl penicillin, and phenoxymethyl penicillin was determined in vitro by using broth dilution and disk diffusion tests. The data were correlated by using a four-category scheme for interpreting minimal inhibitory concentrations (groups 1 to 4) as recommended by a subcommittee of an international collaborative study of susceptibility testing. With cephalothin and ampicillin, groups 1 (susceptible) and 2 (moderately susceptible) were susceptible by the disk test, and with benzyl penicillin, similar results were observed when the interpretive zone standards were changed. Strains categorized as group 4 (very resistant) were resistant by the disk method, but group 3 (moderately resistant) strains were not adequately distinguished by disk testing. Group 3 susceptibility to benzyl and phenoxymethyl penicillins can be predicted by extrapolating results from tests with ampicillin disks.
Failure of Rifampin to Inhibit Frog Polyhedral Cytoplasmic Deoxyribovirus Multiplication
Authors: Kucera Louis S.
Published: June 2012

Resistance of frog virus multiplication to rifampin suggests that components peculiar to cytoplasmic deoxyribonucleic acid replicating viruses (e.g., poxvirus) are not equally sensitive to rifampin.
Inhibition of
Mycoplasma pneumoniae
by Actinomycin D
Authors: Fletcher Ronald D. , Jayavasu Chinrudee , Yoo Sungwhaoh , Albertson John N.
Published: June 2012

Growth of
Mycoplasma pneumoniae
was completely prevented by 0.06 μg of actinomycin D/ml, and 0.00375 μg/ml caused 90% inhibition. It thus appears that
M. pneumoniae
is more susceptible to actinomycin D than previously reported. Low concentrations (0.019 μg/ml) of the antibiotic primarily inhibited ribonucleic acid synthesis and high concentrations (20 μg/ml) inhibited both ribonucleic and deoxyribonucleic acid synthesis.
Use of the 295- to 300-Nanometer Circular Dichroism Trough of Ribonucleic Acid to Study Helix Winding: Effect of Acridine Orange
Authors: Hoener Betty-Ann , Sokoloski Theodore D. , Mitscher Lester A.
Published: June 2012

Acridine orange decreases the amplitude of the 295-nm circular dichroism (CD) trough of ribosomal ribonucleic acid (rRNA) where the trough has been related to coil character. Since acridine orange is known from earlier work to intercalate between base pairs of nucleic acids, causing an unwinding of the coil, and our studies show a decrease in the 295-nm CD trough, it appears that CD measurements may be used to observe relative unwinding of rRNA. Under similar solution conditions, melting temperatures with acridine orange indicate no significant change in the stabilization of rRNA structure by acridine orange. Hypochromicity studies show no increase in the percent base pairing in rRNA when 0.1 M tris(hydroxymethyl)aminomethane (pH 7.6) with 1.35 M KCl is used. These results indicate that CD changes in the amplitude of the 295-nm trough of rRNA are related to helix winding in rRNA.
Enzymatic Acetylation as a Means of Determining Serum Aminoglycoside Concentrations
Authors: Haas Michael J. , Davies Julian
Published: June 2012

A rapid and accurate enzymatic assay has been developed for the determination of blood serum levels of BB-K8 and other suitable aminoglycoside antibiotics.
Natural Colistin Resistance in
Edwardsiella tarda
Authors: Muyembe T. , Vandepitte J. , Desmyter J.
Published: June 2012

All of 37 recent human isolates of
Edwardsiella tarda
were resistant to colistin. All strains were resistant to 6.3 μg of sodium colistimethate per ml; 82% of them were resistant to 100 μg/ml. With 34
Salmonella
strains, the average minimal inhibitory concentration (MIC) was 1.6 μg of sodium colistimethate per ml. There was virtually no overlapping of MIC values between both groups of bacteria. Using the Kirby-Bauer method and 10-μg colistin disks, inhibition zone diameters were less than 11 mm for all
Edwardsiella
strains, and larger for all
Salmonella
strains. An atypical, mannitol-fermenting strain of
E. tarda
was resistant to colistin. It is concluded that
E. tarda
is naturally resistant to colistin, that this property may be helpful in differentiation, and that colistin should be tried in enrichment and selective media for the isolation of
E. tarda
. It was also observed that, under conditions as described, all strains of
E. tarda
were susceptible to streptomycin and to novobiocin, whereas all strains of
Salmonella
were resistant.
Effect of Novobiocin and Its Combination with Tetracycline, Chloramphenicol, Erythromycin, and Lincomycin on the Microbial Generation of
Escherichia coli
Authors: Garrett Edward R. , Won Chong Min
Published: June 2012

Inhibition of the steady-state generation of
Escherichia coli
by the bacteriostatic antibiotic novobiocin is linearly related to drug concentration in the range of 0 to 30 μg/ml. Increased cell sizes result because the drug inhibits cell division. The generation rate dependence on drug concentration depends on the nonionized fraction of novobiocin and is invariant with inoculum size or medium composition. However, the antibacterial activity of novobiocin decreases as the concentration of nutrients and Mg
2+
increases, although the inhibitory action of novobiocin on generation rate remains unchanged for concentrations of Mg
2+
above 8.1 × 10
−4
M. Novobiocin is synergistic in combinations with tetracycline in broth, but not when the Mg
2+
was maintained at 4.05 × 10
−3
M. Combinations of novobiocin with the 50
S
ribosomal subunit inhibitors chloramphenicol, erythromycin, or lincomycin are antagonistic, and the degree of growth inhibition is determined only by that component of the binary combination that would have the greater potency if it were acting alone.
Transduction of Isoniazid Susceptibility-Resistance and Streptomycin Resistance in Mycobacteria
Authors: Saroja D. , Gopinathan K. P.
Published: June 2012

Transduction of resistance to isoniazid and streptomycin as well as susceptibility to isoniazid in
Mycobacterium smegmatis
SN2 has been demonstrated. A method has been described for the selection of isoniazid-susceptible variants after transduction of susceptibility.
Stability of Amphotericin B in Infusion Bottles
Authors: Block Edward R. , Bennett John E.
Published: June 2012

Intravenous solutions of amphotericin B in 5% dextrose water with or without hydrocortisone or heparin demonstrated no appreciable loss of activity when exposed to fluorescent light for up to 24 h at 25 C (room temperature).
Inhibition of Sindbis Virus Replication in HeLa Cells by Poliovirus
Authors: Sreevalsan T. , Rosemond-Hornbeak H.
Published: June 2012

Concomitant infection of HeLa cells with poliovirus and Sindbis (SB) virus allowed replication of poliovirus only. The poliovirus-induced interference with the replication of SB virus was dependent partially on the multiplicity of SB virus used for infection. The observed interference was not sensitive to guanidine. Translation, but not replication of poliovirus, appears to be needed for the restriction of SB virus. Superinfection of SB virus-infected cultures with poliovirus was followed by inhibition of protein, but not by viral ribonucleic acid (RNA) synthesis. Polyribosomes present in SB virus-infected cells were disaggregated subsequent to superinfection. The nascent SB viral RNAs synthesized in cells subsequent to superinfection were not associated with the ribosomal structures. These results indicate that the block in protein synthesis, possibly at the level of initiation, may be the basis of the observed interference.
Relationship Between Chloramphenicol Acetyltransferase Activity and the Number of Resistance Genes
Authors: Iyobe Shizuko , Kono Megumi , Ohara Koji , Hashimoto Hajime , Mitsuhashi Susumu
Published: June 2012

Various mutants of an
Escherichia coli
K-12 strain were prepared, in which a chloramphenicol (CM) resistance gene (
cml
) derived from an R factor, R100-1, was integrated into the chromosome. The CM acetyltransferase (CATase) activity of these strains and the strain carrying R100-1 were determined during exponential growth with the following results. (i) The CATase activity varied, depending upon the site of integration of the
cml
gene on the chromosome. Activity was found to be higher when the
cml
gene was integrated nearer the replication origin of the chromosome, the total enzyme activity found was the sum of activities coded by each gene separately. (iii) When the
cml
gene was in a cytoplasmic state on an R factor, R100-1, the expressed enzyme activity was four-to eightfold higher than that in the chromosomal state, suggesting the existence of about four to eight copies of R factor per chromosome. The CATase activity returned to the level of that expressed by R100-1 when the chromosomal
cml
gene was detached and picked up by an R factor.
Cell Wall Alterations of Gram-Negative Bacteria by Aminoglycoside Antibiotics
Authors: Iida Kyoko , Koike Masaatsu
Published: June 2012

After treatment with aminoglycoside antibiotics,
Escherichia coli
B and
Pseudomonas aeruginosa
P28 showed numerous blebs on the cell wall surface.
Usefulness of an Erythromycin-Resistant Strain of
Mycoplasma pneumoniae
for the Fermentation-Inhibition Test
Authors: Niitu Yasutaka , Hasegawa Sumio , Kubota Hideo
Published: June 2012

The fermentation-inhibition (FI) test for
Mycoplasma pneumoniae
was performed with two strains of
M. pneumoniae
, one susceptible to erythromycin and one highly resistant to erythromycin with cross-resistance to other macrolide antibiotics. Serum titers in children with
M. pneumoniae
pneumonia who received no antibiotic were similar with the two strains. Children with atypical pneumonia with a transient rise in the FI titer with the susceptible strain proved to have received erythromycin at the time of the rise. They showed no rise in the FI titer done with the erythromycin-resistant strain. Oral administration of erythromycin regularly elevated the serum FI titer when the test was done with the susceptible strain. Use of the resistant strain in the test eliminated this false elevation. Tetracycline and chloramphenicol did not elevate the titer, even with the susceptible strain. Use of the strain of
M. pneumoniae
resistant to erythromycin provides a true FI antibody serum titer, avoiding the influence of antibiotics.
Double-Blind Comparison of Phlebitis Produced by Cephalothin Infusions with Buffered and Unbuffered Diluents
Authors: Carrizosa Jaime , Levison Matthew E. , Kaye Donald
Published: June 2012

In a double-blind study with each patient as his own control, a buffered and an unbuffered cephalothin solution was administered to 13 patients in opposite arms for a period of 48 h each. Neither the incidence of phlebitis nor the degree of phlebitis was different with the two diluents, and there was no difference in the time of onset of phlebitis.
Responses of the Murine Myeloid Colony-Forming Cell to Ansamycin Antibiotics
Authors: Horoszewicz Julius S. , Carter William A.
Published: June 2012

The in vitro susceptibility of murine myeloid colony-forming cells to the antiproliferative activities of three ansamycin antibiotics was determined. These cells were found to be 10- to 40-fold more susceptible than the corresponding human ones.
Protection of
Escherichia coli
from Isoniazid Inhibition
Authors: Tritz Gerald J.
Published: June 2012

Inhibition of
Escherichia coli
by isonicotinic acid hydrazide (isoniazid) is a function of the initial cell concentration, concentration of antibiotic, and chemical composition of the medium. An initial concentration of 5 × 10
5
cells/ml in a minimal medium is inhibited by 1 mM isoniazid. The
E. coli
cells are protected from this inhibitory effect by a high concentration of cells in the medium. Protection is also obtained from vitamin-free Casamino Acids, methionine, or choline plus homocystine. However, nicotinic acid, nicotinamide, and pyridoxamine are not able to reverse the effect of isoniazid. Colonies arising on minimal medium supplemented with isoniazid are not due to selection of resistant mutants, because this resistance is transitory and not passed on to the daughter cells. It is hypothesized that this transitory resistance is a manifestation of the cells' ability to transfer the methyl group of methionine to either isoniazid or accumulated nicotinic acid and/or nicotinamide.
Semiautomated Turbidimetric Microbiological Assay for Determination of Cefazolin
Authors: Pitkin Donald , Actor Paul , Holl Walter , Post Alex , Weisbach Jerry A.
Published: June 2012

The Autoturb System, a semiautomated system for photometric bioassay, was used to determine cefazolin content. Suitable conditions for the assay using
Streptococcus faecalis
ATCC 10541 as the indicator organism included a medium pH of 6.0 to 7.0 and an incubation time of 3 to 3.5 h at 36 C. Multiple independent assays of samples from a common batch showed the test to be highly reproducible. Accuracy of the turbidimetric assay was evaluated by comparing data obtained from a chemical (hydroxylamine) and a biological (disk diffusion) assay. The available data show the turbidimetric assay to be a rapid, accurate, and reproducible method for determining the biological activity of cefazolin samples.
Antimicrobial Susceptibility of
Streptococcus mutans
Isolated from Patients with Endocarditis
Authors: Baker Carolyn N. , Thornsberry Clyde
Published: June 2012

Forty-one strains of
Streptococcus mutans
(34 from blood specimens from patients with endocarditis and 7 from stock cultures) were tested for susceptibility to penicillin, ampicillin, methicillin, erythromycin, cephalothin, vancomycin, chloramphenicol, tetracycline, gentamicin, streptomycin, and kanamycin. Minimal inhibitory and bactericidal concentrations were determined by a broth microdilution procedure. Most of the strains were very susceptible to ampicillin, penicillin, and erythromycin, with most strains having minimal inhibitory concentrations of 0.08 μg/ml or less. Most of the strains were also susceptible to cephalothin, methicillin, chloramphenicol, tetracycline, and vancomycin. Gentamicin was the most effective aminoglycoside. The antimicrobial susceptibility patterns are similar to those of other viridans streptococci.
S. mutans
strains have proven to be difficult for some microbiologists to identify. But when organisms suggesting
S. mutans
are isolated from patients with endocarditis, they should be at least identified as nonenterococcal streptococci so that appropriate therapy can be initiated.
Synergistic Action of Ampicillin and Erythromycin Against
Nocardia asteroides:
Effect of Time of Incubation
Authors: Finland Maxwell , Bach Michael C. , Garner Carol , Gold Olga
Published: June 2012

Ampicillin and erythromycin were shown to act synergistically in vitro against the majority of strains of
Nocardia asteroides
tested. With these strains, the minimal inhibiting concentration (MIC) of each drug when combined was reduced 4- to more than 512-fold as compared with the MIC of each antibiotic acting individually against the same strains. The combined action against other strains was at least additive, and occasionally indifferent, but antagonism was not observed. The duration of incubation greatly influenced the MIC of erythromycin but had less effect on the action of ampicillin. Synergistic action was still demonstrable, although less frequently, when the period of incubation was increased from 48 to 72 h.