bluuebunny/crossref_metadata_2025 huggingface dataset:
Subgroup characteristics of respiratory syncytial virus strains recovered from children with two consecutive infections
Authors: Mufson M A , Belshe R B , Orvell C , Norrby E
Published: January 2020

Respiratory syncytial virus strains from 13 children who had repeat infections at least 1 year apart were identified as either subgroup A or subgroup B according to reaction patterns with several monoclonal antibodies directed against the large surface glycoprotein (G), fusion protein (F), nucleoprotein (NP), and matrix protein (M). The virus strains were characterized by enzyme immunoassay, polyacrylamide gel electrophoresis, and immunofluorescence procedures. During the first infection, 10 children had subgroup A strains and 3 had subgroup B strains. Of the 10 children with subgroup A strains during their first infection, 6 had subgroup B and 4 had subgroup A strains during the second infection. Of the three children with subgroup B strains during their first infection, one had subgroup A and two had subgroup B strains during their second infection. No child experienced unusually severe respiratory tract illnesses during second infections with respiratory syncytial virus. Fourfold or greater rises in serum antibody as determined by enzyme immunoassay were as common after the first infection as after the second infection among the seven children tested. Thus, second infections with strains of either subgroup of respiratory syncytial virus did not potentiate respiratory illness, and infection with subgroup A strains of respiratory syncytial virus provided some protection from a second infection with the homologous, but not the heterologous, subgroup of the virus.
Cerebral abscess caused by Klebsiella ozaenae
Authors: Strampfer M J , Schoch P E , Cunha B A
Published: January 2020

Klebsiella ozaenae is the putative cause of ozena or atrophic rhinitis. It has also been commonly isolated as a colonizing organism, but recent reports demonstrate its role as an invasive pathogen, especially in immunosuppressed hosts. We report the first known case of a cerebral abscess caused by K. ozaenae.
Serogrouping single colonies of beta-hemolytic streptococci with achromopeptidase extraction
Authors: Slifkin M , Cumbie R
Published: January 2020

Achromopeptidase (TBL-1; Wako Chemicals, USA, Inc., Dallas, Tex.) prepared as a 2,000-U/ml solution will extract the serogroup antigens from single colonies of groups A, B, C, F, and G streptococci in 1 min at room temperature. This enzyme extraction is not effective for the serogrouping of all group D streptococcus species. Achromopeptidase extracts can be used with latex or coagglutination reagents.
Evaluation of anti-C1q capture assay for detecting circulating immune complexes and comparison with polyethylene glycol-immunoglobulin G, C1q-binding, and Raji cell methods
Authors: Levinson S S , Goldman J O
Published: January 2020

An anti-C1q capture method kit (C1q-immunoglobulin G [IgG]) (Ortho Diagnostics, Inc., Raritan, N.J.) for measuring circulating immune complexes (CIC) was evaluated. The kit showed poor diagnostic sensitivity (P less than 0.005) for identifying CIC in patients with systemic lupus, rheumatoid arthritis, and bacterial endocarditis, as compared with polyethylene glycol-IgG and Raji cell tests (12, 24, and 24 positive, respectively, of 31 patients). Of the patients who were positive with the C1q-IgG test, 25% showed discrepancies when their results were compared with the polyethylene glycol-IgG and C1q-binding test results. Gel filtration chromatography of two of these discrepant sera showed the only peak of C1q-IgG activity to be associated with monomeric IgG (molecular weight, less than 200,000). We concluded that the kit method may be measuring substances other than CIC in some sera, because molecules of C1q attached to IgG should exhibit a molecular weight of greater than 500,000.
Cross susceptibility and absence of cross resistance to cefotetan and cefoxitin
Authors: Barry A L , Jones R N
Published: January 2020

Tests with 2,713 bacterial isolates (members of the family Enterobacteriaceae and gram-positive cocci) from 14 laboratories compared cefoxitin MICs with cefotetan MICs. Strains that were susceptible to cefoxitin could be assumed to be susceptible to cefotetan. Over half of the cefoxitin-resistant isolates of the Enterobacteriaceae were susceptible to cefotetan.
Detection of heat-stable enterotoxigenic Escherichia coli by hybridization with an RNA transcript probe
Authors: Chityothin O , Sethabutr O , Echeverria P , Taylor D N , Vongsthongsri U , Tharavanij S
Published: January 2020

Heat-stable enterotoxigenic Escherichia coli was identified by nucleotide hybridization with RNA transcripts of the gene encoding heat-stable A-2 enterotoxin. Radiolabeled enterotoxin gene RNA transcripts are easier to prepare and avoid the preparation of cloned DNA probes that can be nonspecific if they contain cloning vector DNA.
Model for studying bacterial adherence to skin wounds
Authors: Mertz P M , Patti J M , Marcin J J , Marshall D A
Published: January 2020

The adherence of bacterial pathogens to wounded skin is probably the first step in wound infection. This report describes the development of a bioassay to simulate the adherence of bacteria to wounds. The adherence of bacteria was examined by exposing wounds to known quantities of pathogens, washing the wounds with distilled water, and quantitating the number of adherent bacteria per cm2 of tissue. Our studies focused on the effects of naturally occurring mediators of bacterial adherence, such as wound fluid, serum, and fibronectin. Bacterial adherence was shown to be challenge dependent. Addition of wound fluid, serum, and heat-inactivated serum was shown to reduce the adherence of Pseudomonas aeruginosa to the wound surface compared with that of a saline control. Additional fibronectin treatment of the wound had no effect on the adherence of Staphylococcus aureus. The ability to identify what affects the binding of bacteria to wounded skin can lead to a better understanding of wound infection.
Detection of early antibodies in human immunodeficiency virus infection by enzyme-linked immunosorbent assay, Western blot, and radioimmunoprecipitation
Authors: Saah A J , Farzadegan H , Fox R , Nishanian P , Rinaldo C R , Phair J P , Fahey J L , Lee T H , Polk B F
Published: January 2020

A current concept of the serological response to human immunodeficiency virus (HIV) infection in humans is that antibodies to core antigens (p55, p24, and p15) are detectable earlier during initial stages of antibody production than antibodies against envelope antigens (gp160, gp120, and gp41). Comparative studies of Western blot (immunoblot), radioimmunoprecipitation assay (RIPA), and enzyme-linked immunosorbent assay (ELISA) during initial antibody production are limited to case reports and have not resolved the issue. Thirty of the 37 participants who are part of a prospective study had at least one specimen that was negative for anti-gp41 but had one or more other bands on Western blot. Twenty-seven of these 30 specimens were reactive for anti-gp120/160 in the RIPA. Of the same 30 specimens, kits from Bionetics identified 2 (7%), ElectroNucleonics 4 (13%), Abbott 13 (43%), Du Pont 25 (83%), and Genetic Systems 25 (83%). All participants had evidence of serological progression by Western blot, including a gp41 band, on subsequent visits; the ELISA kits of all manufacturers identified these later specimens with greater accuracy. These data show that the RIPA detects anti-envelope antibodies that may be not detectable by Western blot and that the production of anti-envelope antibodies approximately parallels the production of anti-core antibodies. The false-negative results by ELISA would permit transmission of HIV by blood transfusion from donors in early stages of infection. The sensitivity of licensed ELISA kits should be improved to identify antibody as soon as possible after infection.
High-frequency switching in Candida strains isolated from vaginitis patients
Authors: Soll D R , Langtimm C J , McDowell J , Hicks J , Galask R
Published: January 2020

High-frequency switching and strain variability at the site of infection was assessed in 11 patients with acute Candida albicans vaginitis. By cloning cells directly from the site of infection, it was demonstrated that 4 of the 11 isolates contained multiple-switch phenotypes at the site of infection and that 9 of the 11 isolates were in a high-frequency mode of switching (10(-2) to 10(-3)). Isolates could be separated into four general categories of switching repertoires. To demonstrate that multiple phenotypes at the site of a single infection represented the same strain, EcoRI digests of total cell DNA were separated on agarose gels, and Southern hybridization patterns with two cloned midrepeat sequences were compared.
Production of monoclonal antibodies to Naegleria fowleri, agent of primary amebic meningoencephalitis
Authors: Visvesvara G S , Peralta M J , Brandt F H , Wilson M , Aloisio C , Franko E
Published: January 2020

Monoclonal antibodies (MAbs) to Naegleria fowleri, the etiologic agent of primary amebic meningoencephalitis (PAM), have been produced and used as probes to identify N. fowleri amebae in brain sections of patients who died of that disease. These MAbs were characterized for their specificity by the indirect immunofluorescence assay (IIF), dot immunobinding assay (DIBA), and enzyme-linked immunotransfer blot technique (EITB). The MAbs reacted intensely with all strains of N. fowleri tested originating from different geographic areas in the IIF and DIBA tests, but showed no reactivity with four other species of Naegleria, N. gruberi, N. jadini, N. lovaniensis, and N. australiensis, or a strain of Acanthamoeba castellanii. In the EITB assay the MAbs reacted with the antigens of N. fowleri and produced intensely staining bands at the 160-, 104-, 93-, and 66-kilodalton (kDa) regions and several minor bands at the 30- and 50-kDa regions. The MAbs also reacted with the antigens of N. lovaniensis and produced a darkly staining band at 160 kDa and a diffusely staining band at 116 kDa, indicating that these antigens were shared by the two species. The MAbs, however, showed no reactivity with N. jadini and N. gruberi in the EITB assay.
Epidemiologic factors affecting antimicrobial resistance of common bacterial isolates
Authors: Ellner P D , Fink D J , Neu H C , Parry M F
Published: January 2020

The pattern of antimicrobial resistance of common bacterial isolates obtained from various groups of patients at a large tertiary-care center was compared with the pattern of resistance seen at a primary-care community hospital. At the tertiary-care center, significant differences in susceptibility were seen between pediatric and adult groups. In the tertiary-care center, the inpatients were more likely than the outpatients to have resistant staphylococcal and enterobacterial strains. Comparison of the overall resistance at the tertiary-care center and the primary-care hospital showed that resistance to cephalosporins, piperacillin, and aminoglycosides was significantly higher at the tertiary-care hospital than at the community hospital. Striking differences were noted in the resistance of nosocomial Enterobacter and Citrobacter isolates. Hospitals should be cautious in extrapolating nationwide data to their particular institutions.
Idiopathic production of interleukin-1 in acquired immune deficiency syndrome
Authors: Lepe-Zuniga J L , Mansell P W , Hersh E M
Published: January 2020

We determined the capacity of peripheral blood monocytes from 19 patients with acquired immune deficiency syndrome (AIDS) or related conditions (1 with lymphadenopathy, 8 with AIDS-related complex, and 10 with AIDS) to produce intracellular and extracellular interleukin-1 (IL-1) spontaneously and upon stimulation with bacterial endotoxin. All patients were anti-human T-cell lymphotropic virus type III antibody positive. Results were compared with those obtained with 10 normal controls of similar age. A subset of patients who spontaneously produced high amounts of intracellular and extracellular IL-1 was identified. Total production of IL-1 in this subset was an average of 2.9 times that of controls. It is suggested that spontaneous production of IL-1 in this group represents an in vivo phenomenon since it was associated with more than 3 g of globulins per deciliter of serum, more than 2,300 mg of immunoglobulins per deciliter of serum, higher IgA values, higher titers of anti-Epstein-Barr virus antibodies, and lower neutrophil counts in peripheral blood. The role of Epstein-Barr virus, human immunodeficiency virus itself, or other infectious agents in spontaneous IL-1 production by these patients remains to be determined. Stimulation with endotoxin induced intracellular and extracellular IL-1 production to similar levels in patients and controls. These results show that AIDS patients are able to produce and release IL-1. High idiopathic production of IL-1 identified in some patients can help to explain the hypergammaglobulinemia seen in AIDS patients and might also be related to progression and severity of the disease.
Reaction of fungal products with amebocyte lysates of the Japanese horseshoe crab, Tachypleus tridentatus
Authors: Hodes D S , Heon D , Hass A , Hyatt A C , Hodes H L
Published: January 2020

A commercially available endotoxin assay (CS-TAL) employing a chromogenic peptide and an amebocyte lysate from the Japanese horseshoe crab, Tachypleus tridentatus, gave a positive result with aqueous extracts of all 15 strains of Candida albicans and 1 strain each of Candida tropicalis, Cryptococcus neoformans, and a Mucor species that we tested. Purified glucans prepared from the Candida strains gave the same results. Reconstruction experiments showed that the positive results were not due to contaminating endotoxin. By contrast, assays employing amebocyte lysates of the American horseshoe crab, Limulus polyphemus, were inconsistent. Japanese workers have presented evidence that glucans activate the Tachypleus amebocyte lysate system by acting on an enzyme different from that on which endotoxin acts. Using a Tachypleus lysate preparation (Endospecy; Seikagaku Kogyo, Tokyo, Japan) from which this enzyme was excluded, we demonstrated a 5- to 10-fold drop in reactivity to the aqueous Candida extracts and glucans, whereas reactivity to endotoxin was unchanged. Normal human plasma was shown to decrease the effect of fungal extracts on CS-TAL. This inhibition was completely removed by heating the plasma. Our results suggest that Tachypleus systems may be of use clinically in distinguishing bacterial from fungal infections.
Quantitative antimicrobial susceptibility test for Streptococcus pneumoniae using inoculum supplemented with whole defibrinated sheep blood
Authors: D'Amato R F , Swenson J M , McKinley G A , Hochstein L , Wallman A A , Cleri D J , Mastellone A J , Fredericks L , Gonzalez L , Pincus D H
Published: January 2020

The National Committee for Clinical Laboratory Standards recommends the use of lysed horse blood-supplemented Mueller-Hinton broth for determining the quantitative antimicrobial susceptibility of Streptococcus pneumoniae. This procedure may be difficult for laboratories using previously prepared or commercial MIC systems. Therefore, a study was undertaken to determine whether previously prepared microdilution trays containing Mueller-Hinton broth without blood could be used for determining the antimicrobial susceptibility of S. pneumoniae by adding whole defibrinated sheep blood to the bacterial suspension used to inoculate the trays. The presence of alpha-hemolysis was used as an indicator of bacterial growth. One hundred isolates of S. pneumoniae selected to represent a distribution of susceptibility patterns were tested by the National Committee for Clinical Laboratory Standards method and the sheep blood-supplemented-inoculum method. Greater than 94% agreement between the two methods was achieved. The sheep-blood-supplemented-inoculum procedure was highly reproducible and easy to perform and provides an acceptable alternative for determining the MICs for S. pneumoniae for laboratories using previously prepared or commercial microdilution systems.
Immunization of elderly people with two doses of influenza vaccine
Authors: Gross P A , Weksler M E , Quinnan G V , Douglas R G , Gaerlan P F , Denning C R
Published: January 2020

A total of 104 elderly patients were immunized with one or two doses of the commercial 1985-1986 inactivated influenza vaccine formulation. Two types of vaccines (split virus [SV] vaccine and whole virus [WV] vaccine) and one or two doses 1 month apart were given. No difference in local or systemic reactions was noted among the four groups. The reciprocal geometric mean hemagglutination inhibition antibody titers against influenza A/Philippines/82 (H3N2) after one or two doses were: 78 for SV vaccine (one dose), 65 for SV vaccine (two doses), 55 for WV vaccine (one dose), and 51 for WV vaccine (two doses). Similar nonsignificant differences were observed for the other two antigens contained in the vaccine. The percentage with a hemagglutination inhibition titer of greater than or equal to 1:40 also did not differ after one or two doses. We then compared the postvaccination hemagglutination inhibition titers in young and old patients from previous studies in which apparent differences had appeared. We retested all sera simultaneously on the same day with the same reagents. No significant differences were apparent among age groups. In summary, the humoral immune response to inactivated influenza vaccine in healthy ambulatory elderly patients who have been previously immunized may not differ significantly from that of children and young adults. A booster dose 1 month after the first dose does not enhance immune responses in the elderly.
Freeze-drying of respiratory syncytial viruses for transportation and storage
Authors: Tannock G A , Hierholzer J C , Bryce D A , Chee C F , Paul J A
Published: January 2020

The stabilities of eight strains of respiratory syncytial virus were compared after the strains were freeze-dried in the presence and absence of the stabilizer SPGA, which contains 218 mM sucrose, 7.1 mM dipotassium hydrogen phosphate, 3.76 mM potassium dihydrogen phosphate, 4.9 mM sodium glutamate, and 1% (wt/vol) bovine albumin. Strains freeze-dried in the presence of SPGA showed only small-to-negligible losses at 4 degrees C and losses of approximately 2.0 log10 infectious units at 25 degrees C when held for 45 weeks. Losses at 37 degrees C for one strain were approximately 10-fold greater when the strain was freeze-dried in the absence of SPGA. These results indicate that respiratory syncytial virus strains freeze-dried in the presence of a suitable stabilizer can be transported as unrefrigerated samples without undue losses in infectivity.
Binding of cholera toxin to Giardia lamblia
Authors: McCardell B A , Madden J M , Stanfield J T , Tall B D , Stephens M J
Published: January 2020

Binding of cholera toxin to Giardia lamblia was demonstrated by two slightly different methods: an immunofluorescence technique using antibody to cholera toxin and anti-rabbit immunoglobulin G conjugated to fluorescein isothiocyanate, and a one-step fluorescence method in which G. lamblia was incubated with the B subunit of cholera toxin conjugated to fluorescein isothiocyanate.
Preliminary antimicrobial susceptibility interpretive criteria for cefetamet (Ro 15-8074) and cefteram (Ro 19-5247) disk tests
Authors: Jones R N , Barry A L
Published: January 2020

Preliminary interpretive zone criteria were calculated for cefetamet (Ro 15-8074) and cefteram (Ro 19-5247) by using 10- and 30-micrograms disks and three possible MIC susceptibility breakpoints. Absolute interpretive agreement between MICs and zone size criteria ranged from 91.8 to 97.2%. Very major errors (false susceptibility) were less than or equal to 1.2% for both cephalosporin disk tests. Morganella morganii strains appeared to produce the highest rates of very major interpretive errors with cefetamet disks.
Rapid, cost-effective identification of group A streptococci and enterococci by pyrrolidonyl-beta-naphthylamide hydrolysis
Authors: Wellstood S A
Published: January 2020

Group A streptococci and enterococci were identified by two L-pyrrolidonyl-beta-naphthylamide (PYR) hydrolysis tests. One uses Minitek PYR disks (BBL Microbiology Systems, Cockeysville, Md.); the other uses a swab impregnated with PYR reagent. Both tests and Strep-A-Chek (EY Laboratories, San Mateo, Calif.), a commercially available PYR test, were compared with conventional methods. The PYR methods correctly identified all strains of group A streptococci and enterococci tested.
Specificity of dot hybridization assay in the presence of rRNA for detection of rotaviruses in clinical specimens
Authors: Eiden J , Sato S , Yolken R
Published: January 2020

Nucleic acid hybridization is used to identify viral genomic sequences in clinical and environmental samples. However, RNA virus genomes have been reported to hybridize to mammalian rRNA from uninfected cells under stringent conditions, and caution has therefore been advised in the use of nucleic acid probes for detection of RNA viruses. To evaluate the effect of rRNA on a diagnostic assay for an RNA virus, we tested the specificity of a rotavirus dot hybridization assay with clinical specimens which contained eucaryotic rRNA. The cDNA probe used in this assay contained sequences complementary to all 11 rotavirus genes. Preliminary experiments indicated that hybridization between rRNA and the cDNA probe occurred only with greater than 50 ng of rRNA, and this interaction was easily distinguished from the hybridization of the rotavirus probe with homologous or heterologous strains of the same rotavirus group. When 95 clinical specimens were tested, the rotavirus dot hybridization assay had a specificity of 98.8%. The predictive value of a negative test was 94.2%, although nearly all of the specimens contained rRNA and also reacted with an rRNA probe. Although the specificity of all dot hybridization assays should be individually evaluated, we conclude that our dot hybridization assay for rotaviruses is highly specific even in the presence of quantities of rRNA that may be anticipated in extracts of fecal specimens.
Quality control limits for teicoplanin susceptibility tests and confirmation of disk diffusion interpretive criteria
Authors: Barry A L , Jones R N , Gavan T L , Thornsberry C
Published: January 2020

For monitoring the performance of teicoplanin susceptibility tests, the following quality control limits are recommended: Staphylococcus aureus ATCC 29213, MIC of 0.12 to 0.5 micrograms/ml; Enterococcus faecalis ATCC 29212, MIC of 0.06 to 0.25 micrograms/ml; and S. aureus ATCC 25923, zones 15 to 19 mm in diameter (30-micrograms disks). However, some lots of Mueller-Hinton agar provided unusually large zones of inhibition with both vancomycin and teicoplanin disks, and these lots should be excluded before routine use. Teicoplanin and vancomycin differed only in their activity against oxacillin-resistant strains of Staphylococcus haemolyticus, which had decreased susceptibility to teicoplanin but were fully susceptible to vancomycin. For tests with 30-micrograms teicoplanin disks, zones less than or equal to 10 and greater than or equal to 14 mm in diameter represent resistant and susceptible breakpoints, respectively.
Comparison of Western blot (immunoblot) based on recombinant-derived p41 with conventional tests for serodiagnosis of human immunodeficiency virus infections
Authors: Hofbauer J M , Schulz T F , Hengster P , Larcher C , Zangerle R , Kofler H , Fritsch P , Wachter H , Dierich M P
Published: January 2020

To evaluate the performance of a serological test for human immunodeficiency virus type 1 (HIV-1) infections based on the use of a recombinant envelope gene-derived protein as the antigen, we caused expression of a 1.4-kilobase fragment of HIV.DNA that codes for the complete gp41 transmembrane protein in an Escherichia coli expression vector and used Western blots (WB; immunoblots) prepared with recombinant material (pEX-41) to detect antibodies to HIV-1. This test detected all 339 sera which were positive by a combination of conventional serodiagnostic assays and produced no false-positive results with 311 negative samples. Also no false-positive results were obtained with 20 sera from systemic lupus erythematosus patients which had high titers of cross-reactive autoantibodies. In six cases, the pEX-41 WB proved to be more sensitive than individual assays applied on their own, and in five cases it was even more sensitive than a combination of conventional assays. We tested 221 sera in both our pEX-41 WB and a commercially available recombinant enzyme immunoassay (EIA [Abbott]). The results were identical in 188 cases. A total of 27 sera containing antibodies to gp41 as demonstrated in the pEX-41 WB, as well as the Abbott recombinant EIA, had no antibodies to the recombinant core antigen as measured in the Abbott EIA. However, 25 of these sera did stain the 24-kilodalton band on a WB with purified virus. Six sera that were positive in all of the conventional confirmatory assays and reacted strongly with the pEX-41 WB did not recognize the surface antigen used in the Abbott recombinant EIA. We conclude that the use of WB prepared with recombinant-derived p41 offers a very sensitive and specific method to detect antibodies to HIV.
Serological activity against galactosyl-alpha(1-3)galactose in sera from patients with several kinetoplastida infections
Authors: Avila J L , Rojas M , Towbin H
Published: January 2020

Using rabbit erythrocyte-derived neutral glycosphingolipids enriched for a defined ceramide pentasaccharide as antigens, we have detected elevated anti-galactosyl-alpha(1-3)galactose (anti-G alpha G) antibody values in patients with American cutaneous leishmaniasis (ACL), chronic Chagas' disease, and Trypanosoma rangeli infections compared with normal subjects or with patients suffering from any of 15 other infectious diseases. The specificity of the G alpha G antibodies was determined by inhibition enzyme-linked immunosorbent assays, which revealed that several alpha-galactosyl- but not beta-galactosyl-bearing sugars blocked absorption of G alpha G antibodies to the specific antigen used. G alpha G antibodies were mainly distributed between immunoglobulin classes G and M in three Kinetoplastida infections studied, with a lower increase in reactivity detected in immunoglobulin A. Absorption of highly reactive G alpha G antibodies with purified murine laminin and nidogen, two basement membrane proteins, almost abolished G alpha G reactivity, suggesting the identity of anti-G alpha G with laminin and nidogen antibodies previously reported as elevated in Kinetoplastida infections. In ACL, G alpha G antibodies were detected in 71% of patients having skin lesions with a clinical evolution time of 0.5 month. This percentage increased with the time of evolution of skin lesions, reaching 93% in lesions older than 3 months, and tended to decrease inversely to the induration diameter in the skin leishmanin test. It is proposed that similar epitopes may exist on kinetoplast protozoa and that the determination of G alpha G antibodies may be a highly sensitive assay for the detection of humoral responses to Kinetoplastida infections.
Calcium requirement for syncytium formation in HEp-2 cells by respiratory syncytial virus
Authors: Shahrabadi M S , Lee P W
Published: January 2020

Respiratory syncytial virus (RSV) grown in HEp-2 cells in the absence of calcium did not induce cell fusion and syncytium formation. Although the infected cells contained viral antigens, the cytopathic effect (giant cell formation) typical for RSV was not observed in calcium-free cultures. Infectious virus yield was also slightly reduced (less than a one log10 reduction) in the absence of calcium. An analysis of viral proteins synthesized in both the presence and the absence of calcium revealed that the amount of fusion protein (F1) in calcium-free infected cultures was approximately one-third that in calcium-containing infected cultures. These results underscore the necessity of using calcium-containing growth medium for cell culture isolation and diagnosis of RSV.
Case report of an unclassified microaerophilic bacterium associated with gastroenteritis
Authors: Romero S , Archer J R , Hamacher M E , Bologna S M , Schell R F
Published: January 2020

An unusual microaerophilic gram-negative bacterium was isolated from the stools of two individuals presenting with chronic diarrhea. This bacterium resembled Campylobacter species by colonial morphology and biochemical reactions. However, microscopic examination revealed a fusiform rod with a corrugated surface, rather than a spiral rod. This is the first reported isolation of this bacterium from humans.
Comparison of API ZYM system with API AN-Ident, API 20A, Minitek Anaerobe II, and RapID-ANA systems for identification of Clostridium difficile
Authors: Head C B , Ratnam S
Published: January 2020

The API ZYM system was compared with four anaerobe identification systems for the definitive identification of Clostridium difficile by using 88 cultures of C. difficile grown on Mueller-Hinton blood agar medium. The API ZYM system yielded a distinct and consistent enzyme profile for all test strains, whereas the sensitivities of the other systems in identifying C. difficile ranged from 78 to 96% (AN-Ident, 77.9%; RapID-ANA, 88.6%; Minitek Anaerobe II, 90.9%; and API 20A, 95.5%). The API ZYM system is highly reliable in identifying C. difficile accurately, is rapid, and is relatively simple to use.
RAPIDEC UR, a 2-h miniaturized system for pinpointing uropathogens
Authors: von Graevenitz A , Zollinger-Iten J , Monget D
Published: January 2020

A miniaturized 2-h system (RAPIDEC UR; API System, la Balme-les-Grottes, Montalieu-Vercieu, France) that uses nine enzymatic tests for the diagnosis of most uropathogens was challenged with 330 strains. With few exceptions (Citrobacter, Enterobacter, and Providencia spp., Morganella morganii, and staphylococci other than Staphylococcus saprophyticus), there were distinct patterns that allowed at least a preliminary species diagnosis.
Analysis of antimicrobial susceptibility results using microcomputers
Authors: Chan K W , Ling J , Ling K L , French G L
Published: January 2020

A computer program has been developed on an IBM-PC-compatible microcomputer to analyze antimicrobial susceptibility results of large numbers of organisms tested against a variety of antimicrobial agents. For each species, the output includes the numbers, percentages, cumulative numbers, and cumulative percentages of organisms inhibited at different concentrations of each drug, the MICs for 50 and 90% of organisms tested, MIC ranges, and geometric mean MICs. The distributions of MICs are also plotted as histograms. The program was written in dBASE III command language, but a compiled version allows rapid program execution independently of the dBASE III package.
Oxidation of palmitic acid by Mycobacterium leprae in an axenic medium
Authors: Franzblau S G
Published: January 2020

The ability of Mycobacterium leprae to oxidize palmitic acid during incubation in an axenic medium was studied. By using a Buddemeyer-type detection system, partially purified nude-mouse-derived M. leprae was found to produce 14CO2 from 14C-labeled palmitic acid in a linear fashion for at least 1 week. Procedures known to remove residual host tissue did not diminish the rate of 14CO2 evolution, indicating that bacterial metabolism was being measured. Palmitate oxidation was temperature sensitive, with an apparent optimum of 33 degrees C, but pH insensitive. Bacilli exposed to a variety of antileprosy drugs for 1 or 2 weeks displayed significantly reduced rates of 14CO2 evolution upon subsequent addition of 14C-labeled palmitic acid. This activity could be readily detected with 10(6) bacilli, thus indicating its potential for use in clinical susceptibility testing.
Toxic effect of calcium alginate swabs on Neisseria gonorrhoeae
Authors: Lauer B A , Masters H B
Published: January 2020

Calcium alginate (CA)-tipped swabs have been reported to interfere with the recovery of herpes simplex virus, Chlamydia trachomatis, and Ureaplasma urealyticum and may cause cytotoxicity in cell culture. To determine whether CA swabs also inhibit the growth of Neisseria gonorrhoeae, we carried out a series of experiments using either CA swabs that were toxic or nontoxic in a cell culture cytotoxicity assay or nontoxic rayon or cotton swabs. Leaving a toxic CA swab in 3 ml of Mueller-Hinton broth inoculated with 10(4) CFU/ml caused rapid killing within 6 h at 37 degrees C; colony counts of five strains were less than 1% of those of Mueller-Hinton broth controls. When the tips of toxic CA swabs were inoculated directly and kept at 37 degrees C without holding medium, the swabs were sterile at 6 h. If the same swabs were placed in Amies medium with charcoal, organisms could still be recovered at 6 h. Toxicity was less at room temperature than at 37 degrees C. Inhibition of growth of N. gonorrhoeae was not seen with rayon or cotton swabs. The toxic component was neither the CA fiber nor the aluminum wire but probably the glue used to attach the fibers. We concluded that some lots of CA swabs kill N. gonorrhoeae in vitro. Survival of N. gonorrhoeae is improved with nontoxic swabs, particularly cotton swabs, and Amies medium with charcoal regardless of swab type.
Infection and diarrhea caused by Cryptosporidium sp. among Guatemalan infants
Authors: Cruz J R , Cano F , Càceres P , Chew F , Pareja G
Published: January 2020

During July 1985 to June 1986, fecal excretion of Cryptosporidium oocysts was determined prospectively in a cohort of 130 infants, aged 0 to 11 months, living in a marginal urban area of Guatemala City, Guatemala. A total of 1,280 stool specimens were examined; 158 of them were collected during episodes of diarrhea, and 1,122 were collected during symptom-free periods, every 2 to 3 weeks, from every child. Of the children, 20 (15.4%) excreted Cryptosporidium oocysts during the observation period. Of the diarrheal episodes, 13 (8.3%) were associated with Cryptosporidium sp. Of the control specimens, seven (0.6%) were positive for oocysts. Most of the infections were documented during the months of February to May, at the end of the dry season. Cryptosporidium infections are very common among Guatemalan infants and are an important cause of diarrhea and weight loss. The introduction of liquid or solid foods in the diets of the children, the presence of domestic animals (dogs, cats, or poultry), and the absence of toilet facilities in the house seem to be important risk factors for infection; also, deficient nutritional status may predispose the infected child to Cryptosporidium-associated illness.
Rapid chemiluminescent nucleic acid assays for detection of TEM-1 beta-lactamase-mediated penicillin resistance in Neisseria gonorrhoeae and other bacteria
Authors: Sanchez-Pescador R , Stempien M S , Urdea M S
Published: January 2020

Two new assays for the detection of TEM-1 beta-lactamase-mediated bacterial penicillin resistance were developed that involve the use of specific nucleic acid hybridization. Both techniques are based on a solution-phase hybridization of oligonucleotide probes to the target DNA sequence, solid-phase capture of the probe-target complex, and an amplified chemiluminescent labeling method. One configuration of hybridization probes detected the presence of TEM-1 in Neisseria gonorrhoeae (45 strains), Haemophilus spp., Escherichia coli, Shigella sonnei and Salmonella typhi. A second configuration (TEM-1NH) detected TEM-1 beta-lactamase-mediated penicillin resistance only in N. gonorrhoeae (97 strains) and Haemophilus (6 strains) isolates in which TEM-1 is inserted in a pFA7-type plasmid. Both methods were 100 times more sensitive than a commercially available colorimetric beta-lactamase activity test and approximately 5 times more sensitive than radioisotopic dot blot screening for the gene. The assays are particularly well suited to the analysis of large numbers of samples, can be performed in a total of 4 h, and are sensitive to 10(4) to 10(5) CFU.
Simultaneous detection of antibodies to cytomegalovirus and herpes simplex virus by using flow cytometry and a microsphere-based fluorescence immunoassay
Authors: McHugh T M , Miner R C , Logan L H , Stites D P
Published: January 2020

A sensitive assay for the simultaneous detection of anti-cytomegalovirus and anti-herpes simplex virus antibodies was developed. Two different sizes of polystyrene microspheres were coated with purified viral antigens. Human antiviral antibodies were detected with a biotin-streptavidin amplification procedure with phycoerythrin as the fluorescent label. Microsphere-associated fluorescence was quantitated with a flow cytometer. Sixteen percent of samples initially scored as seronegative for cytomegalovirus and 35% of samples initially scored as seronegative for herpes simplex virus by conventional assays were clearly found positive by the microsphere technique. This flow cytometric assay can simultaneously detect several specific antibodies at levels which are below the sensitivity of standard assays. The dynamic range of this assay is at least sixfold greater than that of enzyme immunoassays. This technique is amenable to numerous serologic assays and could greatly expand the clinical laboratory applications of flow cytometry.
Vibrio cholerae non-O1: production of cell-associated hemagglutinins and in vitro adherence to mucus coat and epithelial surfaces of the villi and lymphoid follicles of human small intestines treated with formalin
Authors: Yamamoto T , Yokota T
Published: January 2020

Clinically isolated Vibrio cholerae non-O1 strains produced more cell-associated hemagglutinins (HAs) on colonization factor antigen agar after ca. 3 h than after ca. 20 h of incubation at 37 degrees C. A high cell-associated HA producer variant of strain TVN-318, grown for 3 h at 37 degrees C, was entrapped in a native mucus coat covering the human ileal mucosa and displayed a striking ability to adhere to the surface of a Formalin-treated mucus coat, in contrast to a poor cell-associated HA producer variant of TVN-318, grown for 20 h at 37 degrees C. Adherence to the Formalin-treated human mucus coat was confirmed with all of the strains tested. V. cholerae non-O1 strains also possessed the ability to adhere to the epithelial surfaces of Formalin-treated human and rabbit ileal or jejunal villi, as well as human lymphoid follicles, in proportion to cell-associated HA levels. The epithelial surface of the lymphoid follicles provided most of the adherence sites for V. cholerae non-O1 strains under the test conditions. We conclude that a mucus coat covering the human small intestinal mucosa is a primary adherence target for V. cholerae non-O1 strains in human intestinal infections and that cell-associated HAs have at least a partial role in the adherence of V. cholerae non-O1 strains to the human small intestine, suggesting a potential role for V. cholerae non-O1 strains in an oral live vaccine.
Microtechnique for serum opacity factor characterization of group A streptococci adaptable to the use of human sera
Authors: Johnson D R , Kaplan E L
Published: January 2020

We have developed a microtechnique for detection of streptococcal serum opacity factor (OF) and for typing of group A streptococci by inhibition of OF. This technique, which involves the use of single wells of standard 96-well tissue culture plates, offers several advantages over previous methods: no advance test preparation is required, allowing tests to be quickly and easily performed; only small quantities of reagents are required; results can be determined visually (qualitative) or by using a photometric enzyme-linked immunosorbent assay plate reader (quantitative); and human serum samples may be quickly and easily screened for OF-inhibitory antibody and subsequently used in place of difficult-to-produce and expensive hyperimmune animal sera for OF characterization of group A streptococci. Fifty-eight samples of normal adult human serum were tested by this new microtechnique for anti-OF antibodies, and 49 (84%) were found to have antibody against 1 or more of the 27 recognized OF-positive serotypes. OF antibodies to M-4, M-2, M-75, and M-48 were most common in these individuals. These 58 human serum samples collectively contained antibody to 25 of the 27 different OF-producing serotypes. Serum samples from four individuals were tested for persistence of OF antibody. OF antibodies to eight different serotypes present in the serum samples collected 7 to 12 years previously were present in the freshly collected sera, indicating that OF antibody persists in human antisera for many years. This new technique has distinct advantages and makes it possible for many laboratories to use this technique to characterize group A streptococci.
Evaluation of different fixatives and treatments for immunohistochemical demonstration of Coxiella burnetti in paraffin-embedded tissues
Authors: Baumgärtner W , Dettinger H , Schmeer N , Hoffmeister E
Published: January 2020

Various fixatives and treatments such as acetone, methanol, Bouin fixative, modified Bouin fixative, 10% Formalin, modified methacarn, periodate-lysine-paraformaldehyde, acetone-methyl benzoate-xylene, and EDTA were evaluated for their effect on the immunoreactivity of Coxiella burnetii in paraffin-embedded tissues by using the avidin-biotin-peroxidase complex and the peroxidase-antiperoxidase procedure. C. burnetii antigen was shown to be present in liver, spleen, and uterus tissues of experimentally infected mice by all methods of fixation and treatment. A positive immunoreaction was seen in cytoplasmic vacuoles of macrophages, as extracellular rod-shaped organisms, and as residual particulate extra- and intracellular debris. Immunoreactivity and cellular preservation, however, varied substantially with the individual fixatives. Optimal immunostaining of C. burnetii was achieved by EDTA treatment and Bouin and acetone fixation. The avidin-biotin-peroxidase technique proved to be slightly more sensitive than the peroxidase-antiperoxidase procedure when primary antibody dilution was used as the criterion for sensitivity.
Determination of serum bactericidal activity against Escherichia coli by an automated photometric method
Authors: Crokaert F , Lismont M J , van der Linden M P , Yourassowsky E
Published: January 2020

The resistance of gram-negative bacteria to complement-mediated serum activity is supposedly an important virulence factor. However, the lack of standardization in the methods used to determine serum activity and the many definitions applied make the comparisons between studies very difficult. We developed a rapid photometric method that we compared with a classical killing one. Escherichia coli in the exponential phase of growth in brain heart infusion broth (final inoculum, 10(7) CFU/ml) at 35 degrees C was added to 50% human serum in Veronal buffer. Viable counts and automatic recording of the variations in the optical densities were obtained for 40 E. coli strains isolated from the stools of healthy adults. With the viable count method, 17 (42.5%) were susceptible (at least a 1 log CFU/ml decrease), 17 (42.5%) were resistant (a 0.6 log CFU/ml increase), 4 (10%) were intermediate (poorly growing inoculum or a decrease of less than 1 log CFU/ml), and 2 could not be classified (nonreproducible results). Agreement between both methods was observed for 87.5% of the stool strains. Eight reference strains of known susceptibilities were classified identically by both methods, leading to a final concordance rate of 89.6%. A total of 129 blood isolates were tested by the photometric method: 64 (49.6%) were resistant, 50 (38.8%) were susceptible 5 (3.9%) showed early regrowth, and 10 (7.7%) were not perfectly reproducible. Of these 129 blood isolates, 5 were also tested by the killing method: 37 (49%) were resistant, 32 (43%) were susceptible, and 6 (8%) were intermediate. The concordance rate between both assays was 89% for the blood isolates; when the minor discordances were ruled out, it was 97%. This automated method could be a useful screening tool for detecting resistance to serum in clinical trials and for studying the in vitro variations of this property.
Relative frequencies of rotavirus serotypes 1, 2, 3, and 4 in Venezuelan infants with gastroenteritis
Authors: Flores J , Taniguchi K , Green K , Perez-Schael I , Garcia D , Sears J , Urasawa S , Kapikian A Z
Published: January 2020

We have used a recently developed monoclonal antibody enzyme-linked immunosorbent assay (K. Taniguchi, T. Urasawa, Y. Morita, H. B. Greenberg, and S. Urasawa, J. Infect. Dis. 155:1159-1166, 1987) for serotyping rotaviruses recovered from 134 Venezuelan infants over a period of 15 months. One hundred and nine of the specimens were typed with the following distribution: serotype 1, 48%; serotype 2, 16%; serotype 3, 22%; and serotype 4, 14%. Three specimens reacted with two different monoclonal antibodies. In addition, 6 specimens (5%) containing enough outer capsid antigen could not be typed; partial RNA sequence analysis of the glycoprotein gene from three of these six strains failed to reveal sequence differences with prototype strains that could be serotyped with the monoclonal antibodies. Variations in the recovery rates of the different serotypes were observed. Serotypes 2, 3, and 4 predominated at the beginning of the study, and serotype 1 predominated at the end of the study. Diarrheal illness appeared to be more prolonged in infants shedding rotavirus serotypes 1 and 3 than in those shedding serotypes 2 and 4.
Dermatophyte-hormone relationships: characterization of progesterone-binding specificity and growth inhibition in the genera Trichophyton and Microsporum
Authors: Clemons K V , Schär G , Stover E P , Feldman D , Stevens D A
Published: January 2020

We reported previously that Trichophyton mentagrophytes contains a cytoplasmic macromolecule which specifically binds progesterone. Progesterone is also an effective inhibitor of growth of the fungus. We report here studies which characterize more fully the specific binding properties and the functional responses of T. mentagrophytes and taxonomically related fungi to a series of mammalian steroid hormones. Scatchard analysis of [3H]progesterone binding in both the + and - mating types of Arthroderma benhamiae and in Microsporum canis revealed a single class of binding sites with approximately the same affinity as that in T. mentagrophytes (Kd, 1 X 10(-7) to 2 X 10(-7) M). Trichophyton rubrum had a protein with a higher binding affinity (Kd, 1.6 X 10(-8) M). Characterization of the [3H]progesterone-binding sites in T. mentagrophytes showed the binder to be a protein which was destroyed by trypsin and heating to 56 degrees C. Previous examination of the steroid-binding specificity in T. mentagrophytes had demonstrated that deoxycorticosterone (DOC) and dihydrotestosterone (DHT) were effective competitors for [3H]progesterone binding. Expansion of this study to include other competitors revealed that R5020 (a synthetic progestin), androstenedione, and dehydroepiandosterone possessed relative binding affinities which were 20, 11, and 9% of that of progesterone, respectively. Other ligands tested were less effective. Competition studies for the binder in M. canis resulted in similar findings: DOC and DHT were effective competitors for [3H]progesterone binding. The growth of A. benhamiae + and -, M. canis, and T. rubrum were all inhibited by progesterone in a dose-responsive manner, with 50% inhibition achieved at concentrations of 9.8 x 10(-6), 1.2 x 10(-5), 1.5 x 10(-5), and 2.7 x 10(-6) M. respectively,.