bluuebunny/crossref_metadata_2025 huggingface dataset:
Bacteroides gracilis, an important anaerobic bacterial pathogen
Authors: Johnson C C , Reinhardt J F , Edelstein M A , Mulligan M E , George W L , Finegold S M
Published: January 2020

Clinical isolates of agar-pitting, formate-fumarate-requiring, anaerobic gram-negative bacilli were recharacterized in consideration of the species descriptions of Bacteroides ureolyticus and the newly described B. gracilis, Campylobacter concisus, and Wolinella sp. During an 11-year period, 7.5% (101 of 1,341) of all specimens yielding anaerobes were found to contain an organism in this group. Of the 71 isolates that were available for study, 43 were B. ureolyticus, 23 were B. gracilis, and 5 were in the Wolinella-C. concisus group. The role in infection and patterns of antimicrobial susceptibility for B. ureolyticus and B. gracilis were studied. Review of the clinical data indicated that 83% of B. gracilis strains were recovered from patients with serious visceral or head and neck infection, whereas 73% of B. ureolyticus isolates were recovered from superficial soft-tissue or bone infections. The strains of B. ureolyticus were uniformly susceptible to the tested antimicrobial agents. B. gracilis, however, showed some striking resistance, with penicillin active against only 67% and the cephalosporins active against 67 to 84% of the isolates tested. The association of B. gracilis with serious deep-tissue infection, coupled with the relatively high frequency of antibiotic resistance, indicates that it is an important, previously unrecognized, pathogen.
Microdilution aminoglycoside susceptibility testing of Pseudomonas aeruginosa and Escherichia coli: correlation between MICs of clinical isolates and quality control organisms
Authors: Larson T A , Peterson L R , Gerding D N
Published: January 2020

The monthly variation in geometric mean MICs (GMICs) of amikacin, tobramycin, and gentamicin for Escherichia coli and Pseudomonas aeruginosa laboratory controls and clinical isolates was followed for 30 months. For 19 months, MICs were determined by using Micro-Media system (MMS; Micro-Media Systems, Inc., Potomac, Md.) microdilution panels, and for the other 11 months, MicroScan (MS; American Scientific Products, McGaw Park, Ill.) MIC test panels were used. The aminoglycoside GMICs for control E. coli and P. aeruginosa were significantly lower with the MS system than with the MMS system. A significant correlation was observed between the GMICs for controls and clinical isolates more frequently with the MMS system than with the MS system. Differences are believed to be related to the criteria used in the selection of quality control strains.
Improved detection times for Mycobacterium avium complex and Mycobacterium tuberculosis with the BACTEC radiometric system
Authors: Kirihara J M , Hillier S L , Coyle M B
Published: January 2020

A total of 2,559 routine clinical specimens were cultured for mycobacteria by using BACTEC Middlebrook 7H12 medium (BACTEC), Lowenstein-Jensen slants (LJ), and Mycobactosel selective Middlebrook 7H11 slants (M7H11). Thirty-three isolates (1.3%) of M. avium complex and 82 isolates (3.2%) of M. tuberculosis were recovered. The BACTEC mean detection time of M. avium complex from 27 smear-negative specimens was earlier than that of conventional media for both decontaminated respiratory specimens (BACTEC, 12 days; LJ, 32 days; and M7H11, 38 days) and untreated tissue and fluid specimens (BACTEC, 8 days; LJ, 30 days; and M7H11, 31 days). The sensitivity for smear-negative M. avium complex with BACTEC (74%) was comparable to that with LJ (74%) and M7H11 (63%). The mean detection times of M. tuberculosis from 56 smear-positive respiratory specimens were 8 days for BACTEC, 16 days for LJ, and 17 days for M7H11, and sensitivities for the detection of positive cultures were 98% for BACTEC, 76% for LJ, and 79% for M7H11. The BACTEC mean detection time of M. tuberculosis in smear-negative specimens was better for tissues and fluids (14 days) than for respiratory specimens (24 days). BACTEC yielded substantially earlier detection of M. avium complex from all specimen types and of M. tuberculosis from smear-positive respiratory specimens. The rapid identification and susceptibility testing of M. tuberculosis in BACTEC agreed completely with conventional tests and provided a 3-week reduction in median time to final reports.
New cause for false-positive results with the cryptococcal antigen test by latex agglutination
Authors: Boom W H , Piper D J , Ruoff K L , Ferraro M J
Published: January 2020

The highly specific and sensitive latex agglutination test for cryptococcal antigen detection in cerebrospinal fluid is routine in many hospitals. Contamination of cerebrospinal fluid by a minute amount of syneresis fluid (surface condensation) from agar gave a strongly positive reaction which was heat stable, was not eliminated by pronase treatment, and was not detected by the normal rabbit globulin controls. These observations were valid for three commercially available test kits and could represent a preventable cause of some unexplained false-positive tests despite the use of adequate controls.
Comparison of immunofluorescence with commercial monoclonal antibodies to biochemical and biological techniques for typing clinical herpes simplex virus isolates
Authors: Balkovic E S , Hsiung G D
Published: January 2020

Immunofluorescence with monoclonal antibody reagents from two commercial sources for differentiating herpes simplex viruses types 1 and 2 demonstrated 100% agreement with cell culture selectivity (chicken embryo and guinea pig embryo cells) and (E)-5-(2-bromovinyl)-2'-deoxyuridine sensitivity for typing a total of 94 clinical herpes simplex virus isolates.
Survey of neuraminidase production by Clostridium butyricum, Clostridium beijerinckii, and Clostridium difficile strains from clinical and nonclinical sources
Authors: Popoff M R , Dodin A
Published: January 2020

Neuraminidase production was investigated in 57 Clostridium butyricum strains, 16 Clostridium beijerinckii strains, and 25 Clostridium difficile strains. Neuraminidase activity was found only in C. butyricum strains originating from one human newborn with neonatal necrotizing enterocolitis, two newborns with hemorrhagic colitis, one infected placenta, and one adult with peritonitis, It was concluded that neuraminidase was not a major virulence factor in C. butyricum strains.
Evaluation of a simple method for growing Mycobacterium haemophilum
Authors: Vadney F S , Hawkins J E
Published: January 2020

Surface paper strips containing hemin (X factor) were tested on Middlebrook 7H10 agar and Lowenstein-Jensen medium to determine if the growth requirement of Mycobacterium haemophilum for iron-containing complexes could be met by this simplified method. One reference strain and seven strains of this species isolated from patients showed good growth around the strips on 7H10 within 2 weeks but failed to grow on Lowenstein-Jensen medium with X-factor strips. Middlebrook 7H10 medium with X-factor strips may be a useful alternative to the preparation of specialized media for the recovery of M. haemophilum from clinical specimens.
Screening method for rapid detection of methicillin-resistant (heteroresistant) Staphylococcus aureus
Authors: Hansen S L , Pope W A
Published: January 2020

A broth screening method was developed to detect methicillin-resistant (heteroresistant) strains of Staphylococcus aureus from primary plates. Lyophilized vials containing cation-supplemented Mueller-Hinton broth, 2% NaCl, and 10 micrograms of methicillin and 6 micrograms of oxacillin per ml were hydrated and tested with 129 methicillin-resistant and 35 methicillin-susceptible strains of S. aureus. With the addition of a tetrazolium indicator after 5 h of incubation, 96.9% of resistant strains were detected. No false-positive results occurred.
Antibiotypes of Bacteroides gingivalis assessed by antimicrobial disks and multivariate analysis
Authors: Notten F J , Nieman F H , Mikx F H
Published: January 2020

Antibiograms with 20 different antimicrobial disks were studied for antibiotyping of Bacteroides gingivalis isolates. The stability of the antibiotypes was tested by passage in mice. Several B. gingivalis isolates of the same subject were used to investigate the presence of different antibiotypes in one individual, while isolates from different subjects were used to investigate individual differences. The antibiotypes were found to remain stable after animal passage. All tested strains of different origin represented different antibiotypes. The isolates from one subject all belonged to the same antibiotype. Principal component analysis of the data showed that two factors were important in the discrimination of the strains of B. gingivalis. One included beta-lactam antimicrobial agents that affect the cell wall. The other included antimicrobial agents that inhibit synthesis of protein and nucleic acid. Both principal component analysis and discriminant analysis proved to be of great use in the reduction of the amount of data and the visualization of the relations between different antibiotypes of B. gingivalis in a linear map. Among the investigated subjects, different antibiotypes of B. gingivalis were found, indicating that in the mouth of an individual, one antibiotype of B. gingivalis predominates and that different persons harbor different antibiotypes of B. gingivalis.
Intravenous catheter-associated fungemia due to Candida rugosa
Authors: Reinhardt J F , Ruane P J , Walker L J , George W L
Published: January 2020

We report a case of intravenous catheter-associated fungemia caused by Candida rugosa; this is the first report of such an infection in a human. Multiple cultures of blood taken over a 24-h period and of the intravenous catheter tip were positive for this unusual isolate. The patient was treated with intravenous amphotericin B and made an uneventful recovery. Intravenous cannulae and other intravascular devices are well recognized as potential sites of intravascular infection by a variety of microorganisms, including several Candida species; however, fungemia caused by C. rugosa has not been reported.
Identification of hydroxy fatty acids in Aeromonas hydrophila, Aeromonas sobria, and Aeromonas caviae
Authors: Canonica F P , Pisano M A
Published: January 2020

Gas-liquid chromatographic analysis of fatty acid methyl esters obtained from clinical isolates of Aeromonas hydrophila, A. sobria, and A. caviae revealed the presence of two hydroxy fatty acid species, 3-OH 12:0 and 3-OH 14:0.
Large Cryptococcus neoformans isolated from brain abscess
Authors: Love G L , Boyd G D , Greer D L
Published: January 2020

Cryptococcus neoformans yeast cells 40 to 60 micron in diameter were seen in an India ink preparation made from a human brain abscess specimen. In culture at 25 degrees C, uniform 5-micron-diameter yeast cells were produced. Inoculation into mice produced yeast cells up to 40 micron in diameter, and brain heart infusion broth culture at 35 degrees C produced yeast cells about 25 micron in diameter. A relationship of yeast cell diameter to incubation temperature is suggested.
Quantitation of HeLa cell monolayer invasion by Shigella and Salmonella species
Authors: Niesel D W , Chambers C E , Stockman S L
Published: January 2020

A major determinant in the virulence of Salmonella and Shigella spp. is the ability of these organisms to invade epithelial cells of the gastrointestinal mucosa and multiply intracellularly. The invasion of cell culture monolayers is a convenient experimental system to evaluate eucaryotic cell penetration and is correlated with the potential of a strain to cause human disease. We have developed an agarose-L agar overlay technique which allows for the convenient quantitation of the number of infected tissue culture cells in a monolayer. Bacterial strains were introduced onto antibiotic-free HeLa cell monolayers. Infected monolayers were washed, and noninternalized bacteria were counterselected with kanamycin (50 micrograms/ml). The number of infected HeLa cells present was determined by overlaying the monolayer with distilled water-agarose (0.5 to 1.5%) followed by an equal volume of 2X L agar. Bacterial colonies formed over infected cells in 24 h at 37 degrees C, and wells were counted with a dissecting microscope under X2 power. Bacterial colonies were not observed with noninvasive variants of Shigella spp. To obtain countable wells (20 to 200 CFU) the multiplicity of infection or invasion times were adjusted. With a 90-min invasion time, the invasive potential of a strain was reflected by the multiplicity of infection needed to produce countable wells. The quantitation of bacterium-invaded cells by using standard bacteriological methods is a convenient and rapid method to evaluate the invasive potential of bacterial strains. Additionally, parameters essential for the invasive process can easily be investigated.
In vitro protective effect of bacteria-derived bovine alpha interferon I1 against selected bovine viruses
Authors: Gillespie J H , Robson D S , Scott F W , Schiff E I
Published: January 2020

We used bacteria-derived bovine alpha-interferon I1 (Bo IFN-alpha I1) to study its antiviral effect in a bovine turbinate cell line on bovine diarrhea virus, infectious bovine rhinotracheitis virus, parainfluenza 3 virus, and pseudorabies virus. We based our study upon replicate tests for each strain by using a block titration system with various concentrations of Bo IFN-alpha I1 against various concentrations of virus. The data were compiled in two-axis tables (replicate X concentration) and were statistically analyzed by the Spearman-Kärber method. An increase in the concentration of Bo IFN-alpha I1 enhanced its protective effect against every test virus strain. Bo IFN-alpha I1 had a marked in vitro effect on the bovine diarrhea viral strains. It demonstrated less protection against the pseudorabies and parainfluenza 3 viruses. Its effectiveness against the two infectious bovine rhinotracheitis viral strains was lesser and of a low order.
autoSCAN-4 system for identification of gram-negative bacilli
Authors: Rhoden D L , Smith P B , Baker C N , Schable B
Published: January 2020

A production model of the autoSCAN-4 system (American MicroScan, Inc., Mahwah, N.J.) was tested with not more than 11 strains each of 73 groups or species of gram-negative bacilli from various Centers for Disease Control culture collections. The strains included typical and atypical strains of enteric fermenters, nonenteric fermenters, and nonfermenters. The autoSCAN-4 system identified 95.3% of all 405 cultures accurately: 95.4% of 307 members of the family Enterobacteriaceae, 96.6% of 29 nonenteric fermenters, and 94.2% of 69 nonfermenters. Manual readings of the same trays provided essentially the same results, with a maximum change of only +1.6% identification accuracy of members of the Enterobacteriaceae. These data were obtained by all required additional tests, including serology and computer consultation when indicated. Only 19 of the cultures tested were misidentified. These were distributed randomly throughout the various groups and species except that Edwardsiella tarda was usually missed because of poor H2S reactions in the test medium. Of six Yersinia enterocolitica isolates, two were not identified. Only one nonenteric fermenter, a Pasteurella sp., and four nonfermenters (three Pseudomonas sp. and one Centers for Disease Control group Ve-2) were misidentified.
Serotypic classification of hantaviruses by indirect immunofluorescent antibody and plaque reduction neutralization tests
Authors: Lee P W , Gibbs C J , Gajdusek D C , Yanagihara R
Published: January 2020

Antisera prepared against 16 strains of hantaviruses isolated from patients with hemorrhagic fever with renal syndrome (HFRS) or from rodents captured in HFRS-endemic and nonendemic regions were titrated against Hantaan virus strain 76-118, Puumala virus strain Sotkamo, and Prospect Hill virus strain Prospect Hill-I by using the indirect immunofluorescent antibody and plaque reduction neutralization tests. Isolates fell into one of four distinct groups or serotypes. Serotype 1 included Apodemus-derived strains, serotype 2 included Rattus-derived strains, serotype 3 included Clethrionomys-derived strains, and serotype 4 included Microtus-derived strains. Serotypic classification of hantavirus infections was possible for humans and rodents in widely varied geographical areas, but in a few instances, sera from patients with HFRS did not conform to any of the four serotypes, suggesting the existence of as yet unidentified serotypes. A definitive serological classification of hantaviruses must await analysis of additional virus isolates.
Rapid identification of Clostridium species by high-pressure liquid chromatography
Authors: Harpold D J , Wasilauskas B L , O'Connor M L
Published: January 2020

High-pressure liquid chromatography was evaluated as a rapid means of identifying various species of clostridia. Isolates were inoculated into a defined medium and incubated aerobically for 1 h at 35 degrees C. The organisms were removed, and the supernatants were derivatized for 1 min at room temperature by the addition of o-phthalaldehyde. The total time required to run each chromatogram was approximately 50 min. Standardized peak heights for each medium component and any new peaks formed were calculated for each isolate and compared with those for uninoculated control medium. Multiple isolates of various Clostridium species gave consistent patterns of medium utilization that could be used for identification. This rapid method can easily be adapted for laboratory use and has the potential for automation.
Combined immunoaffinity cDNA-RNA hybridization assay for detection of hepatitis A virus in clinical specimens
Authors: Jansen R W , Newbold J E , Lemon S M
Published: January 2020

To apply cDNA-RNA hybridization methods to the detection of hepatitis A virus (HAV) in clinical materials, we developed a two-step method in which a microtiter-based, solid-phase immunoadsorption procedure incorporating a monoclonal anti-HAV capture antibody was followed by direct blotting of virus eluates to nitrocellulose and hybridization with 32P-labeled recombinant HAV cDNA. This immunoaffinity hybridization method is simple and involves few sample manipulations, yet it retains high sensitivity (10- to 30-fold more than radioimmunoassay) and is capable of detecting approximately 1 X 10(5) to 2 X 10(5) genome copies of virus. The inclusion of the immunoaffinity step removes most contaminating proteins and thus facilitates subsequent immobilization of the virus for hybridization. It also permits positive hybridization signals to be related to specific antigens and adds a level of specificity to the hybridization procedure. When the method was applied to 23 fecal specimens collected from individuals during week 1 of symptoms due to hepatitis A, 13 specimens were found to be reproducibly positive for HAV RNA by immunoaffinity hybridization, whereas only 11 contained viral antigen detectable by radioimmunoassay.
Detection of bovine herpesvirus 1 DNA immobilized on nitrocellulose by hybridization with biotinylated DNA probes
Authors: Dorman M A , Blair C D , Collins J K , Beaty B J
Published: January 2020

A molecular hybridization technique using biotinylated DNA probes was used to detect bovine herpesvirus 1 (BHV-1) nucleic acid species immobilized on nitrocellulose. Seventeen recombinant plasmids containing HindIII restriction fragments of the BHV-1 genome were compared for their ability to detect immobilized BHV-1 DNA from purified virus and infected cells. One probe, pCB2, labeled by nick translation with either 3H or biotin, detected as little as 10 pg of viral DNA. In time course experiments, BHV-1 DNA could be detected by 2 h postinfection in 10(6) infected cells. BHV-1 DNA was detected in nasal swabs and exudate from experimentally infected cattle, even when specimens had been stored for over a year. In a retrospective study of a respiratory disease outbreak in a feedlot, hybridization was compared with virus isolation for diagnosis of BHV-1 infections. The sensitivity rate was 0.68 with virus isolation as the referent standard. Blot hybridization provides a novel approach with unique applications for the diagnosis of bovine herpesvirus infections.
Evaluation of teicoplanin and vancomycin disk susceptibility tests
Authors: Barry A L , Thornsberry C , Jones R N
Published: January 2020

Disk tests with two glycopeptide antibiotics, teicoplanin and vancomycin, were evaluated, and MICs were compared with those of fusidic acid and coumermycin. For tests with 30-micrograms vancomycin disks, we recommend modification of the current zone size standards to less than or equal to 10 mm for resistant and greater than or equal 15 mm for susceptible. For teicoplanin disk tests, 30-micrograms disks are recommended, with zone size interpretive standards of less than or equal to 10 and greater than or equal 14 mm. Since no resistant clinical isolates are available at this time, susceptibility testing of either drug is rarely necessary, and zone size standards are tentative.
Two-dimensional thin-layer chromatography for the specific detection of hippurate hydrolysis by microorganisms
Authors: Lin J Y , Chen K C , Hale J , Totten P A , Holmes K K
Published: January 2020

Glycine, one of the end products of hippurate hydrolysis by microorganisms, was detected by a rapid, specific technique utilizing two-dimensional thin-layer chromatography. A loopful of growth of each organism from its suitable agar medium was washed, suspended, and incubated with 0.1% sodium hippurate for 30 min at 37 degrees C. The supernatant of the incubated suspension from each organism was then dansylated, and the dansyl derivatives were separated by two-dimensional thin-layer chromatography on polyamide sheets. Glycine, a product of hippurate hydrolysis, was detected under UV light. This technique does not require prolonged incubation and was found to be more specific and reliable than the standard ninhydrin reaction. In addition, it is inexpensive and can be easily conducted in a clinical microbiological reference laboratory. By this method, 100% (22/22) of Campylobacter jejuni and 0% (0/9) of Campylobacter coli reference strains were positive. In addition, 100% (13/13) of group B streptococci, 100% (24/24) of group D streptococci, and 90% (18/20) of Gardenerella vaginalis clinical isolates were positive for hippurate hydrolysis. This method is useful for the identification to the species level of Campylobacter organisms and the biotyping of Gardnerella organisms and for the detection of hippurate hydrolysis by unknown microorganisms.
Morphological variations of Haemophilus parasuis strains
Authors: Morozumi T , Nicolet J
Published: January 2020

Haemophilus parasuis strains isolated from the noses of apparently healthy animals and from animals with pathological conditions were examined for the presence of a capsule, for their ability to agglutinate in acriflavine or after boiling, and for their peptide profile after polyacrylamide gel electrophoresis (PAGE). The capsule was identified by precipitation against hexadecyl trimethylammonium bromide (Cetavlon), by demonstration of iridescence, and by means of a capsule-staining method. We found a group of capsulated strains showing a rather coccobacillary morphology compared with the morphology with polymorphism, varying from rod-like to filamentous, in strains without detectable capsules. The strains of the latter group were agglutinated by acriflavine or by boiling. Soluble antigens of capsulated strains reacting with Cetavlon were thermostable and resisted proteolytic enzymes, thus suggesting the presence of an acidic polysaccharide. A few of the capsulated strains did not precipitate with Cetavlon, which indicated that their chemical composition was different. Acriflavine-positive strains belonging to a definite PAGE pattern (type II) seemed to be associated with pathological conditions more frequently than were capsulated strains which were mostly isolated from nasal cavities of apparently healthy pigs. We put forward the hypothesis that the agglutinability in acriflavine, together with the PAGE profile type II, may be associated with particular structures responsible for virulence.
Guanine is a growth factor for Legionella species
Authors: Pine L , Franzus M J , Malcolm G B
Published: January 2020

Evaluation of previously described chemically defined media for the growth of Legionella pneumophila showed that these media supported poor growth of several strains of L. pneumophila and did not support growth of certain of the Legionella species described later. Growth was stimulated by the dialysate from yeast extract but not by the nondialyzable fraction. Further investigations indicated that the active factors from the yeast extract dialysate were purine or pyrimidine derivatives, and certain known purines and pyrimidines were found to stimulate growth. Of these, guanine universally stimulated growth of all Legionella strains and was a growth requirement for several of the species tested. A balanced, N-(2-acetamido)-2-aminoethanesulfonic acid-buffered, chemically defined medium having guanine or a purine-pyrimidine mix is presented for the general growth of Legionella species.
Techniques for examining Pneumocystis carinii in fresh specimens
Authors: Ruffolo J J , Cushion M T , Walzer P D
Published: January 2020

Pneumocystis carinii was examined in fresh preparations of infected rat lung homogenates and tissue culture supernatants by a variety of light microscope techniques, vital dyes, and histologic stains. Phase-contrast microscopy, Nomarski interference-contrast microscopy, and bright-field microscopy with oblique illumination provided excellent views of P. carinii. Erythrosin B, and to a lesser extent trypan blue, were helpful in assessing organism viability. The use of Triton X-100-Giemsa stain permitted differentiation of the developmental stages in the P. carinii life cycle. The techniques developed here are easily adaptable to the microbiology laboratory and thus should have important clinical and research applications.
Blood-borne pulmonary infection with Nocardia asteroides in a heroin addict
Authors: Vanderstigel M , Leclercq R , Brun-Buisson C , Schaeffer A , Duval J
Published: January 2020

Nocardia asteroides frequently causes primary lung infection with possible hematogenous dissemination to various organs, especially in patients with altered immune responses. The preponderance of pulmonary infections suggests an airborne route of contamination. We report a case of pulmonary nocardiosis in a previously healthy intravenous heroin abuser. The clinical and epidemiologic data strongly suggest a paraphernalia blood-borne infection in this patient, a mode of contamination which has not been previously reported.
Phage types of Staphylococcus aureus received at the Quebec Public Health Laboratory from 1976 to 1983
Authors: Jetté L P
Published: January 2020

Phage typing of 13,579 clinical and environmental strains of Staphylococcus aureus received at the Quebec Public Health Laboratory between 1976 and 1983 was routinely performed to assess the distribution of lytic groups. Strains susceptible to phages 94, 95, and 96 predominated and accounted for 25% of the specimens. The distribution of strains in lytic groups varied with time and specimen source.
High-performance liquid chromatography of mycolic acids as a tool in the identification of Corynebacterium, Nocardia, Rhodococcus, and Mycobacterium species
Authors: Butler W R , Ahearn D G , Kilburn J O
Published: January 2020

High-performance liquid chromatography of bromophenacyl esters of mycolic acid was used as an aid to assign a particular organism to one of four mycolic acid-containing genera. A gradient elution system, with methanol and chloroform, was used to distinguish representative mycolic acid patterns for the genera Corynebacterium, Rhodococcus, Nocardia, and Mycobacterium.
Flying squirrel-associated Rickettsia prowazekii (epidemic typhus rickettsiae) characterized by a specific DNA fragment produced by restriction endonuclease digestion
Authors: Regnery R L , Fu Z Y , Spruill C L
Published: January 2020

The DNA from flying squirrel-associated Rickettsia prowazekii was characterized by using a specific DNA fragment produced by digestion with the enzyme BamHI. The DNA fragment was cloned into a plasmid vector and used to readily distinguish between available human- and flying squirrel-associated R. prowazekii DNAs derived from crude cytoplasmic extracts.
Salt-induced filamentous growth of a Salmonella strain isolated from blood
Authors: Yoshida S , Udou T , Mizuguchi Y , Tanabe T
Published: January 2020

A strain of Salmonella choleraesuis subsp. choleraesuis serovar paratyphi-A isolated from the blood of a febrile patient grew into filaments on a nutrient agar containing various salts, such as NaCl, KCl, MgCl2, NH4Cl, (NH4)2SO4, or (NH4)2HPO4, at concentrations of 50 to 400 mM. The filamentous cells were nonseptate and multinucleate, and they had colony-forming ability. This mutant strain, however, did not show filamentous growth in liquid media which contained the same salts. On nutrient agar containing 20% sucrose but no salts, some of the cells formed large spheroplasts. Both ampicillin treatment and in vivo environment may in part be responsible for the induction of the mutant strain.
Characterization of an organism that produces type E botulinal toxin but which resembles Clostridium butyricum from the feces of an infant with type E botulism
Authors: McCroskey L M , Hatheway C L , Fenicia L , Pasolini B , Aureli P
Published: January 2020

The apparent causative organism from the only reported case of type E infant botulism was isolated and characterized. Except for its ability to produce type E botulinal toxin, this organism (strain 5262) would be unquestionably identified as Clostridium butyricum. This is the second time an organism resembling a defined Clostridium species other than a member of the C. botulinum group has been implicated in infant botulism.
Role of keto acids and reduced-oxygen-scavenging enzymes in the growth of Legionella species
Authors: Pine L , Hoffman P S , Malcolm G B , Benson R F , Franzus M J
Published: January 2020

Keto acids and reduced-oxygen-scavenging enzymes were examined for their roles in supporting the growth of Legionella species and for their potential reactions between the chemical components of the media. When grown in an experimental ACES (2-[(2-amino-2-oxoethyl)-amino] ethanesulfonic acid)-buffered chemically defined (ABCD) broth, the presence of keto acids shortened the lag periods, increased the rates of growth, and gave maximum cell yields. In addition, keto acids affected the specific activities of reduced-oxygen-scavenging enzymes determined during growth. The specific activities of superoxide dismutase of Legionella pneumophila (Knoxville) and L. dumoffii (TEX-KL) were increased three- to eightfold, while that of L. bozemanii (WIGA) was not affected. All strains appeared to be equally sensitive to the effects of superoxide anion (O2-) generated by light-activated riboflavin, and all were equally protected by the presence of keto acids in the ABCD broth. Production of trace amounts of acetate and succinate in pyruvate- and alpha-ketoglutarate-containing media exposed to light suggested that hydrogen peroxide was formed. Pyruvate and alpha-ketoglutarate were products of growth on amino acids, and there was no quantitative evidence that these keto acids were metabolized when they were added to the medium. The rate of cysteine oxidation in ABCD broth was increased by the presence of ferric ion or by exposure to light or by both, and keto acids reduced the rate of this oxidation. ACES buffer was a substrate for the production of O2- in the presence of light, and the combined addition of Fe2+ ions, cysteine, and either keto acid to the medium strongly inhibited the production of O2-. Thus, keto acids inhibited the rate of cysteine oxidation, they stimulated rapid growth by an unknown process, and, in combination with added Fe2+ ions and cysteine, they reversed the toxic effects of light by inhibiting O2- production.
Controlled evaluation of the agar-slide and radiometric blood culture systems for the detection of bacteremia and fungemia
Authors: Weinstein M P , Reller L B , Mirrett S , Stratton C W , Reimer L G , Wang W L
Published: January 2020

A commercially available agar-slide blood culture bottle (Septi-Chek; Roche Diagnostics, Div. Hoffman-La Roche, Inc., Nutley, N.J.) was compared with the radiometric blood culture system (BACTEC; Johnston Laboratories, Inc., Towson, Md.) in 8,544 paired blood cultures from adult patients. The systems were inoculated with equal volumes (10 ml) of blood. Overall, there was no statistically significant difference between the two systems in the recovery of clinically important microorganisms, but significantly more members of the family Enterobacteriaceae other than Escherichia coli were detected by the agar-slide system (P less than 0.005). The agar-slide system detected more fungi, and the BACTEC detected more anaerobic bacteria; however, small numbers of recovered organisms precluded statistical significance. When microorganisms grew in both systems, their presence was detected one or more days earlier in the BACTEC (P less than 0.001). More contaminants grew in the agar-slide system (P less than 0.001). Both systems performed well, and either system should provide high yield and prompt detection of positive blood cultures in patients with bacteremia and fungemia if used in an optimal way as recommended by the respective manufacturers.
Detection of rotavirus with a new polyclonal antibody enzyme immunoassay (Rotazyme II) and a commercial latex agglutination test (Rotalex): comparison with a monoclonal antibody enzyme immunoassay
Authors: Doern G V , Herrmann J E , Henderson P , Stobbs-Walro D , Perron D M , Blacklow N R
Published: January 2020

A total of 176 human fecal specimens were examined for the presence of rotavirus by four different assays: a monoclonal antibody enzyme immunoassay; the original polyclonal antibody enzyme immunoassay marketed by Abbott Laboratories, North Chicago, Ill. (Rotazyme I); a modification of this assay which is now commercially available (Rotazyme II); and a latex agglutination test (Rotalex) recently introduced by Medical Technology Corp., Somerset, N.J. In addition, selected specimens were examined for the presence of rotavirus by electron microscopy, immune electron microscopy, and RNA gel electrophoresis. A total of 40 specimens were positive in the monoclonal antibody enzyme immunoassay, and 136 were negative. Using the results obtained with this procedure as the reference standard, we found the sensitivities of the Rotazyme I, Rotazyme II, and Rotalex tests to be 97.4, 100, and 81.6%, respectively. The specificities of these three procedures were 88.8, 83.9, and 100%, respectively.
Analysis of epidemiologic markers of nosocomial Serratia marcescens isolates with special reference to the Grimont biotyping system
Authors: Sifuentes-Osornio J , Ruiz-Palacios G M , Gröschel D H
Published: January 2020

Seventy-one strains of Serratia marcescens obtained from hospitalized patients of the Instituto Nacional de la Nutricion in Mexico City and two Virginia hospitals (University of Virginia Medical Center and Norfolk General Hospital) were analyzed to find markers useful for the epidemiologic investigation of outbreaks with this organism. Biotyping with commercial microwell systems (API 20# system [Analytab Products, Plainview, N.Y.] and DMS Rapid NFT [DMS Laboratories, Inc., Flemington, N.J.]) was not useful. Biotyping with the system designed by Grimont (assimilation tests, pigment production, and the ability to reduce tetrathionate broth) was helpful to characterize all strains. Of the 37 Mexican strains, 36 belonged to biogroup A 5/8 and 32 were biotype A8b. The 34 strains from the Virginia hospitals were distributed among six different biogroups and 12 biotypes. Significant differences in antimicrobial susceptibility (50% MIC, microgram/ml) between Mexican and Virginia strains were seen with carbenicillin (256 versus 8), piperacillin (64 versus 4), amikacin (16 versus 2), gentamicin (2 versus 0.5), and tobramycin (16 versus 2). Some Mexican strains showed variability in the susceptibility to amikacin because they were low producers of 6'-N-acetyltransferase type I. The Mexican strains seemed to come from a hospital with cross-infection problems because most were isolated from urine, were multiresistant, and more nonpigmented; in contrast, the strains isolated at University of Virginia Medical Center represent the experience of a hospital with scattered S. marcescens infections. The Grimont biotyping scheme is a useful epidemiologic tool for the clinical microbiologist.
Relationship between performance in three of the Centers for Disease Control microbiology proficiency testing programs and the number of actual patient specimens tested by participating laboratories
Authors: Griffin C W , Mehaffey M A , Cook E C , Blumer S O , Podeszwik P A
Published: January 2020

The performance of laboratories enrolled in three of the Centers for Disease Control microbiology performance evaluation programs was studied in relation to the number of actual patient specimens tested by the laboratories. Laboratories were grouped according to the number of specimens tested weekly to compare performance among the groups. Results of the study showed that laboratories, as a group, that tested large numbers of specimens performed better than laboratories that tested small numbers. The infrequency of performing certain tests or identifying certain microbial species can be an important factor in laboratory error. One strategy for laboratories that cannot resolve internal problems associated with low testing volumes would be to limit their testing to procedures that are done well.
Critical evaluation of the AutoMicrobic system gram-negative identification card for identification of glucose-nonfermenting gram-negative rods
Authors: Plorde J J , Gates J A , Carlson L G , Tenover F C
Published: January 2020

During a 6-month study we critically evaluated the accuracy of the AutoMicrobic system Gram-Negative Identification Card (Vitek Systems, Inc., Hazelwood, Mo.) in identifying glucose-nonfermenting gram-negative bacilli by testing 419 selected isolates in parallel with a conventional reference method. Of 356 isolates included in the AutoMicrobic system profile, a total of 307 (86.2%) were correctly identified, 36 (10.1%) were not identified, and 13 (3.7%) were misidentified. Fifty-eight of 63 (92%) isolates not included in the profile were correctly reported as "unidentified organisms." Overall, if the first-choice identification was always accepted, only 18 (4.3%) isolates would have been incorrectly reported. When first-choice identifications appended with the special message "questionable biopattern" were rejected, and organisms were screened for characteristic odor and antimicrobial susceptibility before final acceptance of the AutoMicrobic system report, the number of misidentifications was reduced to 5 (1.2%). The average time to identification with the AutoMicrobic system Gram-Negative Identification Card was 15 h. This compares favorably with the 65 h required by the reference method.
Clinical comparison of a new automated infrared blood culture system with the BACTEC 460 system
Authors: Jungkind D , Millan J , Allen S , Dyke J , Hill E
Published: January 2020

A new blood culture instrument, the BACTEC (Johnston Laboratories, Inc., Towson, Md.) NR-660, which utilizes infrared detection of carbon dioxide from microbial metabolism, was compared with the radiometric BACTEC 460 system. There were 1,554 isolates from 18,785 paired aerobic blood cultures. Of these isolates, 1,303 were isolated from the radiometric 6B medium, and 1,259 were isolated from the NR6A medium (P = 0.06). Analysis of the data indicated no significant differences in recovery when any individual species was considered. When organisms were considered as groups, there were no significant detection differences for gram-negative bacilli, yeasts, or anaerobes. For gram-positive cocci in aerobic medium, the BACTEC 460 detected 84.3% of the total isolates, and the BACTEC NR-660 detected 79.7% (P = 0.04). There were 891 isolates from 13,983 paired anaerobic blood cultures. Of these isolates, 725 were recovered from the radiometric 7D BACTEC medium, and 723 were recovered from the NR7A BACTEC medium (P greater than 0.9). In the anaerobic media there was no significant difference in detection of any organism group, including the gram-positive cocci. When the results of the aerobic and anaerobic media were combined, there was equivalence between the two systems for the detection of gram-positive cocci (P greater than 0.2) and other organism groups. When the ability to detect septic episodes was compared, there was no significant difference for any organism group (P = 0.12). For aerobic media, the mean times for detection were 30.5 and 29.5 h for the BACTEC 460 and NR-660, respectively. For anaerobic media, the mean times for detection were 39.8 and 41.6 h for the BACTEC 460 NR-660, respectively. Compared with the BACTEC 460, the BACTEC NR-660 system had a greater ease of operation, faster test cycle, computerized data base, and equally rapid detection of positive cultures.
Use of the RapID-ANA System to screen for enzyme activities that differ among species of bile-inhibited Bacteroides
Authors: Dellinger C A , Moore L V
Published: January 2020

The RapID-ANA System (Innovative Diagnostics Systems, Inc., Atlanta, Ga.) was used to test 102 strains of 14 species of phenotypically similar bile-inhibited Bacteroides from humans. Bacteroides oris, Bacteroides veroralis, Bacteroides buccalis, Bacteroides melaninogenicus, Bacteroides loescheii, and Bacteroides denticola had very similar enzyme activity profiles. Clear differentiation of these six species by the RapID-ANA System was not possible, but tests for arginine aminopeptidase and beta-glucosidase were helpful. Bacteroides oralis, Bacteroides intermedius, Bacteroides corporis, Bacteroides disiens, Bacteroides bivius, Bacteroides gingivalis, Bacteroides asaccharolyticus, and Bacteroides buccae each had unique enzyme activity profiles. No consistent differences in enzyme activities were found between the two DNA homology groups within Bacteroides melaninogenicus, Bacteroides loescheii, or Bacteroides intermedius. Tests for glycine aminopeptidase, alpha-galactosidase, arginine aminopeptidase, alpha-fucosidase, N-acetylglucosaminidase, reduction of triphenyltetrazolium, and production of indole were helpful in the differentiation of the species studied.
Diagnostic assessment of an enzyme-linked immunosorbent assay for human and canine blastomycosis
Authors: Turner S , Kaufman L , Jalbert M
Published: January 2020

An enzyme-linked immunosorbent assay (ELISA) for blastomycosis was evaluated with 65 human sera from culturally or histologically proven cases of blastomycosis, 53 sera from humans with heterologous infections, and 115 sera from apparently normal people. The diagnostic value of the ELISA was compared with that of the widely used complement fixation (CF) and immunodiffusion (ID) tests. The assay gave a sensitivity of 80% and a specificity of 98% with a minimal positive titer of 1:16. In contrast, the CF and ID tests demonstrated sensitivities of only 40 and 65%, respectively, and both were 100% specific. It was concluded that ELISA titers of 1:32 or greater are indicative of active blastomycosis, whereas lower titers, which might represent cross-reactions, were considered suggestive of the disease. The specificity of low titers should be confirmed by immunodiffusion tests or from the study of serial serum specimens. Preliminary studies with sera from 6 dogs with active blastomycosis and 31 asymptomatic dogs revealed an ELISA sensitivity of 100% and a specificity of 97% when a 1:8 cutoff titer was used. Although a wide range of titers was obtained in both human and canine specimens, no single titer could be relied on to reflect the clinical form of disease. However, a four-fold-or-greater reduction in titer for serial specimens appeared indicative of a favorable prognosis.
Results of a survey of antifungal susceptibility tests in the United States and interlaboratory comparison of broth dilution testing of flucytosine and amphotericin B
Authors: Calhoun D L , Roberts G D , Galgiani J N , Bennett J E , Feingold D S , Jorgensen J , Kobayashi G S , Shadomy S
Published: January 2020

In a survey of 350 laboratories, 41 of 210 respondents indicated that they performed antifungal susceptibility tests. Two-thirds performed 20 or fewer tests per year, and most used a broth dilution method to test amphotericin B and flucytosine activity against Candida albicans. The broth dilution procedure of S. Shadomy and A. Espinel-Ingroff (p. 647-653, in E.H. Lennette, ed., Manual of Clinical Microbiology, 3rd ed., 1980) was the method most frequently cited, and therefore this method was used to test the susceptibility of five isolates of C. albicans and one of Saccharomyces cerevisiae to amphotericin B and flucytosine in seven research laboratories. Agreement among replicates performed on the same day by each laboratory was excellent for both drugs, all values being within 1 twofold drug dilution. Precision from week to week for each laboratory was also good, with 95 and 92% of values being within 1 drug dilution for amphotericin B and flucytosine, respectively. Interlaboratory precision, however, was poor. For amphotericin B, values varied 8- to 32-fold, and for flucytosine, they varied 32- to greater than 512-fold. We conclude that antifungal susceptibility testing is currently being performed in small volumes by numerous laboratories in the United States and that results from one laboratory may not agree with results from another. Improved standardization of fungal susceptibility tests is necessary before their results can be generally applied to clinical situations.
Novel chemical method for the preparation of nucleic acids for nonisotopic hybridization
Authors: Viscidi R P , Connelly C J , Yolken R H
Published: January 2020

A novel chemical method was used to prepare biotin-labeled nucleic acids for nonisotopic hybridization. The method involves the transamination of unpaired cytosine residues in polynucleotides with sodium bisulfite and ethylenediamine. Primary amino groups on the cytosine derivatives are then reacted with biotinyl-e-aminocaproic acid N-hydroxysuccinimide ester. Biotinylated probes hybridized with 1 to 2 pg of nitrocellulose filter-bound DNA and were visualized with a colorimetric detection technique. This method is simpler and less expensive than other methods for the preparation of nonisotopic probes. In addition, it is more versatile since the chemically modified bases can potentially react with other "indicator" molecules or proteins such as an enzyme. The specificity for unpaired cytosine residues is another advantage which could allow for the selective labeling of a specific region of a double-stranded nucleic acid. This improved labeling method should lead to the wider application of hybridization techniques in diagnostic microbiology and basic research in infectious diseases.