bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunofluorescent Detection of Enterotoxin B in Food and a Culture Medium
Authors: Stark Raymond L. , Middaugh P. R.
Published: December 2020

Both
Staphylococcus aureus
strains 243 and S-6 cells producing enterotoxin B and free enterotoxin in food and culture medium were rapidly demonstrated by using the fluorescent-antibody technique. Comparison of cell fluorescence and enterotoxin B production determined by double gel diffusion showed that an estimation of enterotoxin production could be made by observing the degree of cell fluorescence. The fluorescent-antibody technique was used to determine whether cells were producing enterotoxin under varying nutritional and environmental conditions: NaCl concentration, culture aeration, and time and temperature of incubation in Brain Heart Infusion broth and shrimp slurries. At the various NaCl concentrations, the fluorescence of cells was found positively associated with enterotoxin B production only during the first 12 hr of growth. As the NaCl concentration was increased from 0 to 10%, the fluorescence of cells and toxin production decreased. Maximum for cell fluorescence and enterotoxin production was observed at 37 C. Little or no difference in cell fluorescence and enterotoxin production with both strains was found between Brain Heart Infusion broth and shrimp slurry cultures. All results obtained with the fluorescent-antibody technique were verified with double gel diffusion for enterotoxin detection and quantitation.
Isolation of Phenylalanine-Negative
Proteus vulgaris
Authors: Sultan William W.
Published: December 2020

Three phenylalanine-negative
Proteus vulgaris
strains were isolated from three different sources. The significance of these
Proteus
strains has not been fully recognized.
Stability of Rifampin in Dimethylsulfoxide
Authors: Karlson Alfred G. , Ulrich John A.
Published: December 2020

Stock solutions of rifampin remain stable in dimethylsulfoxide for at least 8 months.
Scanning Electron Microscopy of Selected Members of the
Streptomyces hygroscopicus
Group
Authors: Dietz Alma , Mathews John
Published: December 2020

Distinctive variations in whole spore morphology and spore surface morphology of
Streptomyces hygroscopicus
strains, which had been observed previously by the authors by the preshadowed carbon replica technique, were confirmed by observations with the scanning electron microscope.
Rapid Plate Test for Evaluating Phage Induction Capacity
Authors: Mayer V. W. , Gabridge M. G. , Oswald E. J.
Published: December 2020

An agar plate test is presented as a screening test for phage induction capacity of various chemicals.
Interferon Production by Human Leukocytes In Vitro: Some Biological Characteristics
Authors: Lee Spencer H. S.
Published: December 2020

Interferon was optimally produced in human peripheral leukocyte cultures incubated for approximately 19 hr in the presence of Sendai virus at a multiplicity of 10 to 50 EID
50
/cell. For determining whether deoxyribonucleic acid (DNA) synthesis per se was essential for interferon production, 1-β-D-arabinofuranosylcytosine (Ara-C), a potent DNA inhibitor was studied for its effect on interferon production in leukocytic and bone marrow cell cultures. These cells showed no impaired capacity to produce interferon when treated with 15 μg of Ara-C per ml. Interferon yields were also determined in leukocyte cultures treated with actinomycin D (0.1 μg/ml) and puromycin (10 μg/ml) at various times before and after virus inoculation. The data suggested that sequential transcriptive and translational events were required for the de novo synthesis of interferon by the infected leukocytes, in a manner similar to other known virus-induced interferon-producing systems. The synthesis of macromolecules and the effects of antimetabolites in leukocytes and bone marrow cell cultures were followed by measuring the incorporation of thymidine-
2
-
14
C
, uridine-
5
-
3
H
, and L-phenylalanine-
1
-
14
C
. The effect of 0.1 μg of actinomycin per ml on the capacity of leukemic leukocytes to produce interferon was also studied. Preliminary data showed that, in contrast to nonleukemic leukocytes, interferon production by leukemic leukocytes was only partially inhibited by actinomycin.
Bacteriophage Typing of Salmonellae. II. New Bacteriophage Typing Scheme
Authors: Ibrahim Abdelaziz E.
Published: December 2020

A phage-typing technique for salmonellae is described. One battery of phages was used to type three serotypes of
Salmonella
, namely,
S. typhimurium, S.typhimurium
var.
copenhagen
, and
S. heidelberg
. In all, 443
S. heidelberg
cultures were typed into 22 phage types, 185
S. typhimurium
cultures into 35 phage type, and 92
S. typhimurium
var.
copenhagen
cultures into 26 phage types. The stability of the phage types was established by retyping 168 cultures belonging to all three serotypes. The epidemiological significance of the phage types demonstrated was evaluated by comparing phage types obtained from the University of Minnesota and those from the National Animal Disease Laboratory. Further investigation of the
S. heidelberg
phage types has shown that the cultures represented repeated isolates from the same birds or from a group of birds in the same flock.
Epidemiological Fingerprinting of
Pseudomonas aeruginosa
by the Production of and Sensitivity to Pyocin and Bacteriophage
Authors: Farmer J. J. , Herman Lloyd G.
Published: December 2020

A new method has been devised to trace cross-infection by
Pseudomonas aeruginosa
. Unknown strains growing logarithmically in liquid media were treated with mitomycin C to induce the liberation of pyocin and phage. The lysates were then tested against 27 selected indicator strains, and the zones of clearing were differentiated as to killing by pyocin or lysis by phage. Twenty-four standard pyocin-phage lysates were then applied to each of the unknowns, and the sensitivity pattern was recorded. Thus, an “epidemiological fingerprint” consisting of 51 operational characteristics was established for each isolate. Organisms from the same source had identical or similar fingerprints, but organisms from different origins could easily be distinguished. Pyocin production, pyocin sensitivity, and phage production were found to be stable genetic characters; however, spontaneous mutations in phage sensitivity were frequently encountered. The epidemiological fingerprint has proven to be a sensitive tool in establishing the identity or dissimilarity of unknown strains. This method has been of great value in tracing the epidemiology of
P. aeruginosa
in the hospital environment. Each of the 157
P. aeruginosa
strains tested has been typable by this method.
Control Mechanisms Operative in a Natural Microbial Population Selected for Its Ability to Degrade L-Lysine. III. Effects of Carbohydrates in Continuous-Flow Systems Under Shock Load Conditions
Authors: Grady C. P. L. , Gaudy A. F.
Published: December 2020

Two naturally selected microbial populations were maintained under continuousflow conditions with glucose or magnesium growth-limiting. The reactors were subjected to shock loads by changing the influent substrate from L-lysine to a mixture of L-lysine and glucose, L-lysine and fructose, or L-lysine and ribose. During the subsequent transient state, the following parameters were examined: lysine chemical oxygen demand (COD), carbohydrate COD, total COD, biological solids concentration, cell protein, enzymatic capability (lysine-degrading enzymes), and the rate of lysine removal. The carbohydrate was then removed from the influent and the same parameters were examined until a new steady state was established. In all cases, glucose and fructose caused a significant repression of the synthesis of lysine-degrading enzymes, resulting in a decrease in the enzymatic capability of the cells. In the carbon-limited reactor, the faster the flow rate, the greater was the repression, whereas, in the magnesium-limited reactor, the slower the flow rate, the greater was the repression. The introduction of ribose into the reactors caused an initial increase in lysine enzymatic capability followed by a slight repression when ribose degradation started.
Growth, Sporulation, and Germination of
Clostridium perfringens
in Media of Controlled Water Activity
Authors: Kang Chunghee K. , Woodburn Margy , Pagenkopf Andrea , Cheney Roberta
Published: December 2020

Requirements in terms of water activity (a
w
) for the growth, sporulation, and germination of
Clostridium perfringens
were determined. Strain A48 was used in all phases, and in addition either NCTC 8239 or NCTC 8797 was used for growth, sporulation, and germination studies. The desired a
w
of the test media was obtained by the addition of one of three solutes: glycerol, sucrose, or sodium chloride. The freezing point depression method was used to determine the a
w
. The basal medium for growth and germination was Fluid Thioglycollate Medium. It had an a
w
of 0.995 and produced maximum growth and fastest growth rate among the six levels of a
w
tested. The lowest a
w
supporting growth and germination of
C. perfringens
was between 0.97 and 0.95 in the test media made with sucrose or sodium chloride and 0.93 or below in the test media adjusted with glycerol. Spore production by
C. perfringens
in Ellner's or modified medium required a higher a
w
than growth.
Rapid Determination of
Salmonella
in Samples of Egg Noodles, Cake Mixes, and Candies
Authors: Banwart George J. , Kreitzer Madeleine J.
Published: December 2020

A glass apparatus system was compared with a standard enrichment broth-selective agar method to test samples of egg noodles, cake mixes, and candy for the presence or absence of salmonellae. The glass apparatus system used fermentation of mannitol, production of H
2
S, or motility, in conjunction with a serological test of flagellar antigens, to detect salmonellae. No salmonellae were detected in 173 samples of food products. Of these samples, 171 were found to be
Salmonella
-negative after 48 hr with the glass apparatus system. After 72 hr, the standard
Salmonella
procedure yielded 38 samples which produced
Salmonella
false-positive results on selective agars. Inoculation of samples with cultures of
Salmonella
showed that approximately one inoculated cell could be detected after 48 hr of incubation with the glass apparatus. The standard
Salmonella
test requires a minimum of 72 hr for completion. Compared with the standard
Salmonella
test, the glass apparatus system is a more rapid and simple system that can be used to determine the presence or absence of
Salmonella
in these food products.
Effectiveness of Acetic Acid, Betadine, Amphyll, Polymyxin B, Colistin, and Gentamicin Against
Pseudomonas aeruginosa
Authors: Hedberg Mary , Miller John K.
Published: December 2020

The in vitro effectiveness of three germicides and three chemotherapeutic drugs against hospital-isolated strains of
Pseudomonas aeruginosa
was determined. Solutions of 1% acetic acid, 0.5% Amphyll, and 0.1% Betadine were bactericidal for six strains tested within 15 min at room temperature. Over a 3-year period at the Albany Medical Center Hospital, the percentages of strains of
P. aeruginosa
susceptible to polymyxin B, colistin, and gentamicin did not increase. During this 3-year period, polymyxin B and colistin were administered at the hospital but gentamicin was not.
Isolation of a Bacterial Inhibitor from Green Olives
Authors: Fleming H. P. , Walter W. M. , Etchells J. L.
Published: December 2020

A compound inhibitory to lactic acid bacteria was isolated from green Manzanillo olives. The inhibitor is a phenolic compound, is devoid of acid-hydrolyzable reducing sugar, and has a bitter taste. Freezing the olives prior to extraction caused chemical changes which greatly increased the level of the inhibitor, whereas heating prior to freezing prevented its formation.
Comparison of the Fatty Acids of Proteolytic Type B and Nonproteolytic Types E and F of
Clostridium botulinum
Authors: Kimble C. E. , McCollough M. L. , Paterno V. A. , Anderson A. W.
Published: December 2020

Lipids were extracted from vegetative cells and spores of
Clostridium botulinum
. The total lipids extracted averaged approximately 3.8% of the dry weight of vegetative cells and 2.5% of the dry weight of spores of types 61E, “F,” and 115B. The fatty acids were analyzed in the form of their methyl esters by gas-liquid chromatography. Infrared spectroscopy, mercuric acetate fractionation, and silver nitratethin layer chromatography served as complementary means of analysis. The total fatty acids included straight chain, saturated, unsaturated, and cyclopropane acids. Hexadecanoic and tetradecanoic acids were the predominant acids in both the spores and vegetative cells. Together, they comprised over 50% of the total fatty acids. Unsaturated acids were the second major group. These were primarily 7,8-tetradecenoic, 9,10-hexadecenoic, 7,8-hexadecenoic, 11,12-octadecenoic, and 9,10-octadecenoic acids. Nonproteolytic types 61E and “F” possessed an 18-carbon diunsaturate, which was not found in the vegetative cells or spores of proteolytic type 115B. A mechanism for the synthesis of unsaturated and cyclopropane acids was proposed.
Activation of Coagulase Clotting by Trypsin Inhibitor
Authors: Orth D. S. , Anderson A. W. , Montgomery M. W.
Published: December 2020

Egg white trypsin inhibitor activated coagulase clotting when added to a final concentration between 2 and 60 mg/ml. The greatest increase in clotting rate was observed in reaction mixtures containing the lowest concentrations of serum and plasma. Maximal activation was reached with 40 mg of trypsin inhibitor per ml when either serum or plasma was used as the source of coagulase-reacting factor (CRF). The increased rate of clotting is partly due to inhibition of plasmin. Freezing and thawing reduced plasma clotting inhibition. Soybean trypsin inhibitor also activated the coagulase reaction. The increased rate of clotting was observed with a coagulase preparation from organisms which produced plasminogen activators and with the culture supernatant fraction from organisms which did not activate plasminogen to plasmin. The tube test for coagulase could be made more sensitive for some strains of staphylococci by increasing the concentration of CRF (added as plasma or serum) by adding trypsin inhibitor, or both.
Incidence of Infectious Drug Resistance Among Lactose-Fermenting Bacteria Isolated from Raw and Treated Sewage
Authors: Sturtevant Alton B. , Feary Thomas W.
Published: December 2020

Raw and treated sewage samples were examined for antibiotic-resistant, lactose-fermenting bacteria. Approximately 1% of the total lactose-fermenting bacteria were multiply resistant. Of these organisms, 50% were capable of transferring all or part of their resistance to a drug-sensitive recipient. Only 43% of those isolated on media containing a single antibiotic were capable of resistance transfer, whereas 57% of those recovered on multiple antibiotic plates transferred resistance. R factors conferring resistance to chloramphenicol, streptomycin, and tetracycline; streptomycin and tetracycline; and ampicillin, streptomycin, and tetracycline accounted for 22, 19, and 15%, respectively, of those identified. The data indicate a significant level of infectious drug resistance among the intestinal bacteria of the urban population.
Rapid Plaque Assay for Encephalomyocarditis Virus
Authors: Baker David A. , Glasgow Lowell A.
Published: December 2020

A liquid overlay plaquing technique is described which offers a rapid and simple plaque assay system for small plaque variants of encephalomyocarditis virus.
Quantitation of Tail Lesions in Vaccinia-Infected Mice
Authors: Joshi N. N. , Jones M. , McColl J. D.
Published: December 2020

When mice were infected with vaccinia virus via the tail vein, the number of lesions was influenced by the injection site. A site 3 cm from the base of the tail is of greatest practical value.
Atypical Reactions of
Escherichia coli
on Eosin Methylene Blue Agar
Authors: Parisi Joseph T. , Marsik Frederic J.
Published: December 2020

Evidence is presented that atypical reactions of
Escherichia coli
on eosin methylene blue agar are due to variations in
p
H in localized areas of the medium.
Microbiological Evaluation of the Vacuum Probe Surface Sampler
Authors: Petersen Norman J. , Bond Walter W.
Published: December 2020

The development of the vacuum probe, a new device for surface sampling, was recently reported. The original technique was slightly modified and a microbiological evaluation was conducted. The probe proved to be an effective sampling device, removing 98% and recovering 88% of surface contaminants resulting from the accumulation of airborne microorganisms. The probe was decidedly less effective in removing and recovering handling contamination than fallout contamination. There was also evidence that certain microorganisms could not survive prolonged exposure to airflow in the probe. However, the vacuum probe procedure recovered twice as many microorganisms as did the swab-rinse technique when compared directly.
Production and Properties of Galactosidases from
Corticium rolfsii
Authors: Kaji Akira , Ichimi Tae
Published: December 2020

When
Corticum rolfsii
was grown in a medium containing bran extract under aerobic conditions, it secreted α-D-galactosidase and β-D-galactosidase into the culture fluid. Pectin also stimulated the production of these enzymes, whereas galactose, glucose, and sucrose stimulated their production to a lesser degree.
C. rolfsii
produced greater amounts of both enzymes than
Aspergillus niger
. Both galactosidases in the culture medium hydrolyzed α- and β-
p
-nitrophenyl-D-galactosides as well as lactose, stachyose, melibiose, and raffinose. Both exhibited optimal activity at
p
H 2 to 4 and were quite stable under acidic conditions. α-Galactosidase was separated from β-galactosidase by column chromatography.
Improvement of the Microbiological Assay for Calcium Leucovorin
Authors: Tanguay A. E.
Published: December 2020

The calcium leucovorin assay was improved by adding THORAL germicide which resuspended the cells so that an accurate turbidity reading could be obtained.
Pour Plates or Streak Plates?
Authors: Van Soestbergen A. A. , Lee Ching Ho
Published: December 2020

The pour plate method of counting bacteria is more precise than the streak plate method, but, on the average, it will give a lower count.
Primary Isolation Medium for
Cryptococcus neoformans
Authors: Vogel R. A.
Published: December 2020

The isolation and identification of
Cryptococcus neoformans
is improved by use of a potato dextrose medium containing urea-antibiotic supplements and a
p
H of 3.5.
Viral Susceptibility Range of the Fathead Minnow (
Pimephales promelas
) Poikilothermic Cell Line
Authors: Solis Juan , Mora Emilio C.
Published: December 2020

The viral susceptibility range of a poikilothermic cell line derived from the fathead minnow (
Pimephales promelas
) (FHM) to infection by a number of homoiothermic viruses representing most of the presently recognized viral groups and a member of the psittacosis-lymphogranuloma-trachoma group of agents was studied. All infectious agents, except poliovirus types 1 and 3, infectious bursal agent, and an avian infectious bronchitis virus (IBV) strain, readily multiplied in the FHM cell culture system, producing a detectable cytopathic effect. Although inconclusive evidence was obtained with two other avian IBV strains, these results indicated the ability of the FHM cell culture system to readily support the propagation of a variety of cytopathogenic homoiothermic viral agents.
Survey of Tall-Fescue Pasture: Correlation of Toxicity of
Fusarium
Isolates to Known Toxins
Authors: Yates S. G. , Tookey H. L. , Ellis J. J.
Published: December 2020

Several aspects of fescue foot in cattle suggest that this disease is caused by fungi growing on fescue grass. Certain fungi isolated from winter pasture yield toxins when grown on synthetic medium. Most of these toxin producers belong to the genus
Fusarium.
All but 1 of the 21 toxic and 7 questionably toxic
Fusarium
isolates produce either 4-acetamido-4-hydroxy-2-butenoic acid γ-lactone, or 4β, 15-diacetoxy-8α-(3-methylbutyryloxy)-12, 13-epoxytrichothec-9-en-3α-ol, or both.
Detection of Griseofulvin and Dechlorogriseofulvin by Thin-Layer Chromatography and Gas-Liquid Chromatography
Authors: Cole R. J. , Kirksey J. W. , Holaday C. E.
Published: December 2020

A rapid and accurate method is described for the determination of griseofulvin and dechlorogriseofulvin extracted from
Penicillium urticae
with chloroform. Thinlayer chromatography was used to tentatively identify griseofulvin or dechlorogriseofulvin, or both. Two gas-liquid chromatographic systems provided additional qualitative information and simultaneous quantitation of the individual compounds.
Production of the Monamycins, Novel Depsipeptide Antibiotics
Authors: Hall M. J. , Hassall C. H.
Published: December 2020

Methods are described for the production of the monamycins by
Streptomyces jamaicensis
in shake flasks and jar fermentors. The effects on the fermentation of variations in
p
H, temperature, medium composition, volume of inoculum, and strain of the organism are discussed. The methods employed for the extraction and for the microbiological assay of the antibiotics are outlined.
Survival of Gram-Negative Bacteria on Plastic Compounded with Hexachlorophene
Authors: Taylor Gerald F.
Published: December 2020

Gram-negative bacteria representing nine genera were screened for their ability to survive surface exposure to polyethylene sheet plastic containing chemically compounded hexachlorophene (0.25%). Subcultures were made at hourly intervals over a 6-hr period of time. An exceedingly large drop in viable cells beginning at the 1-hr exposure was noted for each genus except one tested on the hexachlorophene-plastic, whereas most nonadditive controls grew bacterial colonies too numerous to count.
Microbiological Aspects of Ethylene Oxide Sterilization
Authors: Kereluk K. , Gammon R. A. , Lloyd R. S.
Published: December 2020

The death rate kinetics of several sporeforming and nonsporeforming microorganisms, including radiation-resistant cocci, were determined by exposing them to a mixture of ethylene oxide and dichlorodifluoromethane (500 mg of ethylene oxide per liter, 30 to 50% relative humidity, and 54.4 C). Spore survivor curves obtained from tests of inoculated and exposed hygroscopic and nonhygroscopic carriers showed that the spores of
Bacillus subtilis
var.
niger
are more resistant to ethylene oxide than are spores of
Clostridium sporogenes, B. stearothermophilus
, and
B. pumilus.
The decimal reduction times (expressed as
D
values at 54.4 C-500 mg of ethylene oxide per liter) obtained under the test conditions for
B. subtilis
var.
niger
spores on hygroscopic and nonhygroscopic carriers exceeded the values obtained for the other organisms considered, both sporeformers and nonsporeformers. The decimal reduction times for the vegetative cells of the radiation-resistant organisms (
Micrococcus radiodurans
and two strains of
Streptococcus faecalis
) and the ATCC strain of
S. faecalis
demonstrated comparable resistance to ethylene oxide with the spores of
C. sporogenes, B. stearothermophilus
, and
B. pumilus
, but not those of
B. subtilis
var.
niger.
Nutrition Requirements of
Pleurotus flabellatus
Authors: Srivastava H. C. , Bano Zakia
Published: December 2020

The mycelium of
Pleurotus flabellatus
was grown in a synthetic medium to obtain accurate information on its nutritional requirements. Among various carbon sources tried, the organism was found to utilize hexose sugars more readily than other sugars. Ammonium citrate was found to be the best source of nitrogen. The yield of dry matter increased as the concentration of nitrogen was increased up to a certain stage beyond which there was no increase in the yield, but the crude protein content of the mycelium increased. Detailed studies on the effect of varying the concentrations of other major nutrients, i.e., potassium, phosphorus, calcium, and magnesium, on the growth and crude protein content of the mycelium were also carried out. Optimal
p
H range was fairly broad, lying between 4.5 to 7.5.
Occurrence of the Ciliate Protozoa
Bütschlia parva
Schuberg in the Rumen of the Ovine
Authors: Dehority B. A.
Published: December 2020

The holotrich ciliate protozoa,
Bütschlia parva
Schuberg, has been observed in the rumen of the ovine. Limited data suggest that the concentration of
B. parva
in the rumen follows a diurnal cycle similar to that of the other holotrichs.
Behavior of Salmonellae in Sliced Luncheon Meats
Authors: Goepfert J. M. , Chung K. C.
Published: December 2020

Salmonellae inoculated onto the surface of bologna and liver cheese survived protracted storage at 5 C. Salmonellae grew when the meats were incubated at room temperature.
Lid Method for Evaluating Zone of Inhibition of Treated Fabrics
Authors: Pradip I. S. , Shu L. , Curtis P. R.
Published: December 2020

Stainless-steel wire cloth lids were found to be advantageous in the evaluation of zones of inhibition with germicide-treated cotton fabrics.
Identification of
Mycobacterium kansasii
by Susceptibility to Hydroxylamine
Authors: Gruft Howard , Osterhout Mary
Published: December 2020

Among biochemical tests useful in the study of mycobacteria, the hydroxylamine test is shown to be an effective tool in the differentiation of
Mycobacterium kansasii
from saprophytic strains of group III acid-fast bacilli when combined with the photochromogen test.
Antimicrobial Action of Some Citrus Fruit Oils on Selected Food-Borne Bacteria
Authors: Dabbah Roger , Edwards V. M. , Moats W. A.
Published: December 2020

The antimicrobial properties of essential oils, terpineol, and orange oil, in particular, varied according to the type of bacteria tested. Terpineol and other terpeneless fractions of citrus oils appeared to have greater inhibitory effect on food-borne bacteria than the other citrus oils or derivatives. Gram-positive bacteria were, in general, more sensitive to essential oils than gram-negative bacteria. Terpineol extended the shelf life of commercially pasteurized skim milk, low-fat milk, and whole milk for more than 56 days at 4 C. Orange oil extended the shelf life of skim milk and low-fat milk for the same period.
Method for Isolation and Identification of
Corynebacterium vaginale (Haemophilus vaginalis)
Authors: Dunkelberg Wilbur E. , Skaggs Romulus , Kellogg Douglas S.
Published: December 2020

A method for the clinical isolation and recognition of
Corynebacterium vaginale (Haemophilus vaginalis)
is presented. Wet mount and stained characteristics of genital tract discharges, cellular and colonial morphology of the bacilli, inhibition by H
2
O
2
, lack of a catalase, and fermentation of particular carbohydrates are the determinant factors. The method enables differentiation of the species from unclassified diphtheroids common to the genitourinary tract.
Acid-Precipitated M Protein Compared with a Column-Eluted M Protein Preparation from Type 12, Group A Streptococci
Authors: Noble Robert C. , Moody Max D.
Published: December 2020

An M protein preparation of group A streptococci, precipitated with 0.03
m
sodium acetate buffer (
p
H 4.0) was compared with a column-eluted M protein preparation. Absorption spectra and methyl pentose content were similar in both preparations. Acrylamide gel electrophoresis patterns were different. Gel diffusion demonstrated two lines of fusion in the preparations. More antigens could be demonstrated in both preparations by using immunoelectrophoresis. Neither the
p
H 4 precipitate nor the column-eluted preparation appeared to be a pure M protein preparation.
Potentially Infectious Agents Associated with Shearling Bedpads
Authors: Sidwell Robert W. , Westbrook Louise , Dixon Glen J. , Happich William F.
Published: December 2020

Glutaraldehyde-tanned woolskin pads which are used for the prevention of decubitus ulcers in bed patients were experimentally contaminated with polio or vaccinia viruses. Two methods of exposure, direct contact and aerosol, were used in separate experiments. Attempts were made to remove or inactivate these virus contaminants by laundering the woolskins in a quaternary ammonium disinfectant, a phenolic disinfectant, or alkalinized glutaraldehyde, in combination with an anionic detergent or a nonionic detergent. The effect of a commercial detergent-sanitizer was also studied. The virus titers were significantly reduced in all experiments, but only laundering in glutaraldehyde in combination with either detergent lowered the vaccinia virus titers to below detectable limits. High concentrations of glutaraldehyde altered the texture of the wool and leather apparently by precipitating a component of the detergent onto the fibers. In all the poliovirus experiments, the virus was still detectable on either or both the wool and the leather of the pads after laundering. The rinse water from each experiment was tested for the presence of virus. No vaccinia virus was recovered, but poliovirus was demonstrated in titers up to 10
3
cell culture 50% infectious doses.
Comparison of Antistreptolysin O Latex Screening Test with the Antistreptolysin O Hemolytic Test
Authors: Klein George C. , Baker Carolyn N. , Moody Max D.
Published: December 2020

This report describes a comparison of the Behringwerke antistreptolysin O (ASO) latex screening test with the ASO hemolytic test. Agreement between the two tests was poor when Difco streptolysin O (SLO) reagent was employed in the hemolytic test; approximately 34% of the sera with ASO titers in the normal range of the hemolytic test gave false-positive latex test reactions. However, the percentage of false-positive latex test reactions was only 5% when Behringwerke SLO reagent was used in the hemolytic test. An assay of the Difco and Behringwerke SLO reagents against an ASO standard indicated that the Difco SLO reagent was more potent than the Behringwerke SLO reagent. The lack of agreement between the Behringwerke latex test and the hemolytic test using Difco SLO reagent is attributed to the potency of the SLO reagents.
Polymyxin-Coagulase-Mannitol-Agar
Authors: Orth D. S. , Anderson A. W.
Published: December 2020

A selective, differential plating medium was developed for the isolation and identification of coagulase-positive and mannitol-fermenting staphylococci. Coagulase produced by growing
Staphylococcus aureus
caused an opaque zone of fibrin to form around each colony. Several strains of
S. aureus
produced a visible coagulase reaction by 8 hr, and all strains gave a positive reaction before 12 hr. Mannitol fermentation was usually observed between 12 and 36 hr. Rabbit serum was filtered through Sephadex G-100 to obtain plasmin- and plasminogen-free coagulase-reacting factor (CRF). False-negative reactions, caused by staphylokinase and staphylococcal Müller factor action on plasminogen, were eliminated when this CRF was used. False-positive reactions by lipolytic, coagulase-negative staphylococci were reduced, since gel filtration removed the serum lipoprotein which served as a primary source of opacity. The addition of 75 μg of polymyxin B per ml selectively retarded the growth of
S. epidermidis
and minimized false-positive reactions caused by citrate-utilizing gram-negative rods. The preparation, characteristics, and use of the medium are presented.
Determination of Untreated Whole-Milk Effects on In Vitro Antibacterial Activity
Authors: Van Natta J. P. , Lo P. W. , Chang T. S.
Published: December 2020

The effect of fresh whole milk without pasteurization or other pretreatment on in vitro antibacterial activity of selected compounds was determined in broth dilution. The milk was collected by hand directly from dairy goats, or by syringe or cannula from bovine quarters showing low bacterial counts. Antibacterial activity was determined in 50% (v/v) milk-broth medium against sensitive mastitis-etiologic strains of
Streptococcus agalactiae
and
Staphylococcus aureus.
The indicator salt 2,3,5-triphenyltetrazolium chloride was incorporated in the milk broth medium to determine inoculum growth. Contaminant interference was circumvented through early as well as late readings and comparisons with uninoculated control tubes, with and without the test compounds. Application of the method with more than 75 compounds, including nitrofurans, antibiotics, and other chemicals uncovered marked degrees of milk interference. The method warrants routine use among preliminary screens to relate in vitro with in vivo observations of antimicrobial activity. Similar procedures may be used with serum, skim milk, or mastitis-milk media for separating effects due to protein, lipid, or other elements in product evaluation.
Assay of Chikungunya Virus in Cell Monolayers by Immunofluorescence
Authors: Hahon Nicholas , Hankins William A.
Published: December 2020

Chikungunya virus was quantitatively assayed by counting immunofluorescent foci after infection of BHK21/C13 cell monolayers. The speed and efficiency of virus attachment to cells were markedly enhanced when augmented by centrifugal force. By this procedure, a proportionality was obtained between the number of immunofluorescent foci and the volume of inoculum. Virus penetration into cells was linear and complete within 15 min at 35 C. From observations on the sequential development of viral antigen within cells and immunofluorescent focus counts, foci of infected cells may be enumerated as early as 16 hr after inoculation of cell monolayers. A linear function was demonstrated between immunofluorescent focus counts and relative virus concentration. The immunofluorescent assay was comparable in sensitivity but more precise and rapid than virus assays based on the intracerebral inoculation of suckling mice or on plaque counting. By the immunofluorescent procedure, the 50% neutralizing end point of antiviral serum was rapidly and quantitatively determined.
Comparative Enumeration of Lipophilic and Nonlipophilic Cutaneous Diphtheroids and Cocci
Authors: Smith Rodney F.
Published: December 2020

Swabbing skin to collect bacteria for enumeration revealed that a single washing or rinsing of the swab in buffer removed between 90 and 95% of the bacteria collected. Further removal of the remaining bacteria from the initial swab by repeated washings of the swab produced plate counts that showed nearly proportional decreases in the numbers and types of bacteria retained or eluted from the swab. None of the commonly isolated cutaneous bacteria was retained or eluted from the single swab in numbers that misrepresented measurement of their proportions present in the sample. Populations of nonlipophilic bacteria on skin when present were mainly gram-positive catalase-producing cocci. Diphtheroids when present were chiefly lipophilic. Media containing furoxone were selective for cutaneous diphtheroids. The concentration of furoxone used affected isolation and enumeration of the diphtheroids. Lipophilic diphtheroids from the stratum corneum were basically aerobic and anaerobic incubation reduced or eliminated this group from enumeration studies. Lipophilic furoxone-resistant aerobic diphtheroids from several areas, particularly the nasal passages, occurred in numbers inversely proportional to the numbers of staphylococci for periods up to 11 months. The cocci-diphtheroid relationships occurred independently of the total number of aerobic bacteria present, the transient appearance of yeasts or gram-negative bacilli, the required use of certain antibiotics by the subjects, climate, age, and sex.
Herbicide Transformation
Authors: Lanzilotta R. P. , Pramer David
Published: December 2020

A strain of
Fusarium solani
isolated from soil by enrichment techniques used propanil (3′, 4′-dichloropropionanilide) as a sole source of organic carbon and energy for growth in pure culture. The primary product of the transformation of propanil by
F. solani
was isolated and identified as 3,4-dichloroaniline (DCA). This compound accumulated in the medium to a level (80 μg/ml) which stopped further herbicide utilization. Herbicide utilization by
F. solani
was influenced by various environmental and nutritional factors. It was more sensitive to acid than alkaline
p
H. Added glucose and yeast extract increased the rate of propanil decomposition, and the reduced aeration retarded growth of the fungus and herbicide utilization. The growth of
F. solani
on propionate was inhibited by added DCA.
Pathogenicity of
Clostridium perfringens
for Germ-Free Guinea Pigs After Oral Ingestion
Authors: Horton Richard E. , Madden David L. , McCullough Norman B.
Published: December 2020

Germ-free guinea pigs died with signs and lesions of acute enterotoxemia after oral ingestion of
C. perfringens
types B, C, D, and E. The signs and lesions observed resembled those seen in acute enterotoxemia of sheep and cattle and the naturally occurring disease seen in “ex-germ-free” guinea pigs.
C. perfringens
type A was found to be innocuous. Conventional guinea pigs did not become ill after ingestion of any of the five toxigenic types.
Spectra of Susceptibility of
Neisseria meningitidis
to Antimicrobial Agents In Vitro
Authors: Devine Leonard F. , Hagerman Cline R.
Published: December 2020

The minimal inhibitory concentrations of 49 antimicrobial agents for 37 to 40 meningococcal strains freshly isolated from the nasopharynx of healthy carriers were determined. Coumermycin A
1
and rifampin were the most effective agents tested. The geometric mean values of the minimal inhibitory concentrations for coumermycin A
1
and rifampin were 0.0001 and 0.02 μg/ml, respectively.
Preliminary Report on the Development of a Diffusion-in-Gel Method for the Diagnosis of Ram Epididymitis
Authors: Myers Donald M. , Siniuk Alicia A.
Published: December 2020

A simple gel-diffusion technique is described for the diagnosis of ram epididymitis caused by
Brucella ovis.
The results are shown to be very similar to those obtained by the complement-fixation test, which is currently the standard method of diagnosis. The method is suitable for use in the field and is expected to facilitate the control of ram epididymitis in areas where laboratory facilities are not available.
Serratia marcescens
: Biochemical, Serological, and Epidemiological Characteristics and Antibiotic Susceptibility of Strains Isolated at Boston City Hospital
Authors: Wilfert James N. , Barrett Fred F. , Ewing W. H. , Finland Maxwell , Kass Edward H.
Published: December 2020

The biochemical, serological, and epidemiological characteristics of 95 strains of
Serratia marcescens
isolated at the Boston City Hospital were examined. Several strains were shown to be endemic, and the majority of isolates were cultured from urine or respiratory secretions.
Serratia
species were highly resistant to polymyxin B and the cephalosporins, and various proportions were also resistant to other antibiotics including kanamycin, but all of the isolates were sensitive to gentamicin. The appearance of resistance to kanamycin and nalidixic acid among endemic strains was demonstrated. The nosocomial nature of
Serratia
infections, particularly those involving the urinary tract, was confirmed. Many clinical bacteriology laboratories currently fail to identify the nonpigmented strains.
Growth from Spores of
Clostridium perfringens
in the Presence of Sodium Nitrite
Authors: Labbe Ronald G. , Duncan Charles L.
Published: December 2020

The method by which sodium nitrite may act to prevent germination or outgrowth, or both, of heat-injured spores in canned cured meats was investigated by using
Clostridium perfringens
spores. Four possible mechanisms were tested: (i) prevention of germination of the heat-injured spores, (ii) prior combination with a component in a complex medium to prevent germination of heat-injured spores, (iii) inhibition of outgrowth of heat-injured spores, and (iv) induction of germination (which would render the spore susceptible to thermal inactivation). Only the third mechanism was effective with the entire spore population when levels of sodium nitrite commercially acceptable in canned cured meats were used. Concentrations of 0.02 and 0.01% prevented outgrowth of heat-sensitive and heat-resistant spores, respectively. Nitrite-induced germination occurred with higher sodium nitrite concentrations.
Bacterial, Fungal, and Actinomycete Populations in Soils Receiving Repeated Applications of 2,4-Dichlorophenoxyacetic Acid and Trifluralin
Authors: Breazeale F. W. , Camper N. D.
Published: December 2020

Soil samples were collected from an untreated plot and plots receiving repeated applications of 2,4-dichlorophenoxyacetic acid (2,4-D) and α,α,α-trifluoro-2, 6-dinitro-
N,N
-dipropyl-
p
-toluidine (trifluralin); they were then plated on media specific for bacteria, fungi, and actinomycetes. The actinomycete colony count in the trifluralin-treated plot was greater than the control, but the same as the control in the 2,4-D-treated plot. The bacterial count was lower in both treated plots. Fungal colonies in the trifluralin-treated plots were greater than the control, but not different from the control in the 2,4-D-treated plot.
Type 2 Bovine Adenovirus as an Adventitious Contaminant in Primary Bovine Embryonic Kidney Cell Cultures
Authors: Mohanty Sashi B. , Lillie Mary G.
Published: December 2020

Three lots of primary bovine embryonic kidney cell cultures obtained from commercial sources were found to contain type 2 bovine adenovirus. These cell cultures, apparently derived from healthy fetuses, required long incubation periods before the virus could be detected.
Combined Medium to Determine Deoxyribonuclease Activity and Phenylalanine Deamination by
Enterobacteriaceae
Authors: Oberhofer Thomas R. , Maddox Louise
Published: December 2020

A combination medium has been developed to aid in the identification of
Serratia
and urease-negative
Providencia
recovered from clinical specimens.
Short-Term Storage at 4 C of Trypsinized Tissues
Authors: Probst Peter G. , Orr Henry C.
Published: December 2020

Cells dispersed from tissues of certain animals remained viable for several days at 4 C although the per cent of viable cells varied among the different species.
Chikungunya Virus Infection of Cell Monolayers by Cell-to-Cell and Extracellular Transmission
Authors: Hahon Nicholas , Zimmerman W. Douglas
Published: December 2020

Both cell-to-cell and extracellular transmission of chikungunya virus infection was demonstrated in BHK21/C13 cell monolayers. The mode of virus infection may depend on the cell line. Virus transmission in L-929 and guinea pig lung cell lines was extracellular.
Salmonellae in Fish Meal Plants: Relative Amounts of Contamination at Various Stages of Processing and a Method of Control
Authors: Morris George K. , Martin William T. , Shelton William H. , Wells Joy G. , Brachman Philip S.
Published: December 2020

Previous studies have shown that Menhaden fish meal, a common ingredient of animal feeds, is frequently contaminated with salmonellae. Animals that eat contaminated feed may become infected. If they, in turn, are eaten by humans, they may be a means by which salmonellae are introduced into the human population. Epidemiological studies of the fish-meal industry were carried out to determine the sources of salmonellae in fish meal and the factors affecting the persistence and survival of salmonellae during the processing of fish meal. Examination of 190 fish immediately after they came from the Gulf of Mexico revealed no salmonellae, but salmonellae were frequently isolated from samples of fish taken from the boats when they arrived at the plants. Salmonellae were also frequently isolated from dockside water at each of the plants. Approximately 50% of the samples taken in the raw fish processing areas were contaminated with salmonellae. The percentage of samples yielding salmonellae decreased progressively through the various sequences of processing, but more than 15% of the samples taken from the finished products were also positive. Salmonellae were isolated from the raw area of the plant most frequently while the plant was operating and less frequently when the plant was idle, whereas in the processing area of the plant the reverse was true. Salmonellae appeared to survive and multiply in the processing area of the plant while the plant was idle, which resulted in contamination of the first portion of each day's production. Salmonellae in the processed fish meal were reduced to nondetectable levels by reprocessing the first 45 min of each day's production.
Simple Disposable Method for Quantitative Cultures of Urine
Authors: Benner E. Jack
Published: December 2020

A disposable kit was tested as a means of detecting significant bacteriuria by quantitative culture of urine. The total error in 3,563 specimens tested by five investigators was less than 1%. The method was very effective in differentiating significant bacteriuria, i.e., more than 100,000 bacteria per ml of urine from uninfected urine. In specimens from patients with urinary tract abnormalities who had mixed bacterial flora, the absolute numbers obtained with the dip-inoculum method had a 10% variation when compared to results obtained by calibrated loop or dilution pour plate methods. Therefore, the main utility of the kit is for screening and following patients after therapy. A significant delay in time between inoculation of the medium in the kit with the freshly voided urine and incubation of the kit to promote growth did not affect the reliability of the kit as a method of doing quantitative urine cultures to detect bacteriuria.
Relation of the Heat Resistance of Salmonellae to the Water Activity of the Environment
Authors: Goepfert J. M. , Iskander I. K. , Amundson C. H.
Published: December 2020

The effect of water activity (a
w
) on the heat resistance of eight strains of
Salmonella
was studied. Heat resistance of the organisms increased as the a
w
of the heating menstruum was reduced. Sucrose afforded the cells a greater degree of protection than did fructose, glycerol, and sorbitol. A direct correlation between a
w
and heat resistance could not be established over the range of a
w
levels tested in this study. There was variation among the strains of salmonellae in the magnitude of the increase in heat resistance as the a
w
level was reduced. All strains of
Salmonella
tested showed a greater increase in heat resistance than
S. senftenberg
775W as the environment became drier. Washed cells had
D
values 25 to 75% lower than unwashed cells. Prior growth of the organisms in media with a reduced a
w
increased the heat resistance of the organisms when glycerol, but not when sucrose, was the controlling substance.
Formic Hydrogenlyase Induction as a Basis for the Eijkman Fecal Coliform Concept
Authors: Hendricks Charles W.
Published: December 2020

Many
Enterobacter
species recovered from a relatively unpolluted freshwater stream had the capacity to produce gas from glucose, lactose, and formate at 44.5 C. Composition of the evolved gas was shown to be CO
2
and H
2
, which suggested that the enzyme system formic hydrogenlyase functions as the basis for the Eijkman fecal coliform concept. It is postulated that there are at least two different and distinct biochemical types of
Enterobacter
in the natural aquatic environment: one that lacks an active formic hydrogenlyase at 44.5 C and is associated with the intestinal tract of man and certain animals, and another which possesses the active enzyme at the elevated temperature and is found in soil or on vegetation free from fecal pollution.
Effect of Temperature on Radiosensitivity of Newcastle Disease Virus
Authors: DiGioia G. A. , Licciardello J. J. , Nickerson J. T. R. , Goldblith S. A.
Published: December 2020

Newcastle disease virus was irradiated at temperatures ranging from 2.2 to 60 C. An interaction between the thermal and ionizing energy was observed in the temperature region of 49 to 60 C. At 2.2 C, the hemagglutinin was considerably more radioresistant than the infectivity property. It is believed that radiation inactivation of Newcastle disease virus infectivity at low temperatures was due to nucleic acid degradation and at higher temperatures was due to protein denaturation.