bluuebunny/crossref_metadata_2025 huggingface dataset:
Early detection of oxacillin-resistant staphylococcal strains with hypertonic broth diluent for microdilution panels
Authors: Dillon L K , Howe S E
Published: January 2020

A total of 292 coagulase-positive and 111 coagulase-negative staphylococcal strains were tested in microdilution MIC panels containing 16 to 0.13 microgram of oxacillin per ml diluted in cation-supplemented Mueller-Hinton broth with and without an additional 2% NaCl. All strains were tested using the stationary-phase inoculum procedure with an incubation temperature of 35 degrees C. Test results were recorded after 16 to 20 h of incubation; staphylococcal strains susceptible to oxacillin (less than or equal to 2 micrograms/ml) were reincubated for 20 to 24 h, and endpoints were determined again. Oxacillin resistance was found in 27 (9%) of the 292 coagulase-positive strains and 39 (35%) of the 111 coagulase-negative strains. Of these resistant strains, 5 (19%) of the 27 coagulase-positive strains and 13 (33%) of the 39 coagulase-negative strains were detected 24 h earlier in cation-supplemented Mueller-Hinton broth with 2% NaCl than in cation-supplemented Mueller-Hinton broth without the additional NaCl. However, 9 (33%) of the 27 resistant coagulase-positive strains and 10 (26%) of the 39 resistant coagulase-negative strains were detected only after an additional 24 h of incubation. Oxacillin MICs for the 265 coagulase-positive susceptible strains and 72 coagulase-negative susceptible strains were not affected by the additional 2% NaCl. These results support the utility of adding 2% NaCl to the broth diluent for the early detection of oxacillin-resistant staphylococcal strains and the necessity of extended incubation for those strains which initially appear to be susceptible to oxacillin after only 16 to 20 h of incubation.
New recommendations for disk diffusion antimicrobial susceptibility tests for methicillin-resistant (heteroresistant) staphylococci
Authors: McDougal L K , Thornsberry C
Published: January 2020

The agar disk diffusion susceptibility test was reevaluated for its ability to discriminate between susceptible and resistant Staphylococcus aureus (128 strains) and coagulase-negative staphylococci (19 strains) when tested with methicillin, oxacillin, and nafcillin. The results show that the current recommendations for disk potencies and interpretive zone diameters do not fit well with MIC correlates that we now recommend. Based on data from this study, we suggest that these parameters of the test be changed. For methicillin, we recommend a 10-micrograms disk with breakpoints of less than or equal to 11 mm (greater than or equal to 16 micrograms/ml) to indicate resistance and greater than or equal to 15 mm (less than or equal to 4 micrograms/ml) to indicate susceptibility. For oxacillin and nafcillin, we recommend 4-micrograms disks with breakpoints of less than or equal to 12 mm (greater than or equal to 8 micrograms/ml) to indicate resistance and greater than or equal to 16 mm (less than or equal to 2 micrograms/ml) to indicate susceptibility. MIC breakpoints were from a broth microdilution system which used a medium containing salt. If one of these three penicillins were to be selected for routine tests, we would recommend oxacillin, based on our data, but we recognize that this may depend upon the population of staphylococci within a particular hospital.
Relative frequency of rotavirus subgroups 1 and 2 in Venezuelan children with gastroenteritis as assayed with monoclonal antibodies
Authors: White L , Perez I , Perez M , Urbina G , Greenberg H , Kapikian A , Flores J
Published: January 2020

Monoclonal antibodies recently developed against the 42,000-dalton protein of two rotavirus strains were used in an enzyme-linked immunosorbent assay to determine the subgroup specificity of 252 specimens collected during a 45-month period from Venezuelan children with rotavirus gastroenteritis. Subgroup 2 rotavirus was shed by 85% of the children, whereas only 14% shed subgroup 1 rotavirus (one-half of them in a 3-month period). No differences were found in the occurrence of fever and vomiting between children shedding either rotavirus subgroup, but it appeared that the syndrome tended to last longer in children shedding subgroup 2 rotavirus. The monoclonal subgrouping enzyme-linked immunosorbent assay seemed to be more sensitive than an immune adherence hemagglutination assay, an enzyme-linked immunosorbent assay with polyclonal antibodies, or the electrophoretic analysis of RNA extracted from the virus. Overall, 99% of the specimens could be subgrouped by this assay.
Epidemiological analysis of the significance of low-positive test results for antibody to hepatitis B surface and core antigens
Authors: Hadler S C , Murphy B L , Schable C A , Heyward W L , Francis D P , Kane M A
Published: January 2020

To determine the significance of certain serological test results commonly encountered in hepatitis B virus testing, we reviewed serological test data from nine studies of hepatitis B conducted between 1980 and 1982. Three tests, for hepatitis B surface antigen and for antibodies to hepatitis B surface antigen and hepatitis B core antigen (anti-HBs and anti-HBc), were used to measure hepatitis B virus infection risk in various populations. Two results, low levels of anti-HBs alone and low levels of anti-HBc alone, occurred at constant frequencies (2.72 and 0.4%, respectively), regardless of the prevalence of HBV infection in the population. Positivity for low levels of anti-HBs alone persisted for 1 year in less than one-half of those studied; in addition, response to hepatitis B virus vaccine was augmented in only one-third of this group. Positivity for low levels of anti-HBc alone did not persist in any of 11 persons studied. These findings indicate that presently available tests for anti-HBs and anti-HBc at low levels are often nonspecific and should be interpreted with caution.
Streptococcus pyogenes streptolysin O as a cause of false-positive CAMP reactions
Authors: Tapsall J W , Phillips E A
Published: January 2020

The synergistic hemolysis of sheep erythrocytes in the CAMP reaction by the sequential action of staphylococcal beta-lysin and the CAMP factor of group B streptococci is the only known function of this extracellular product of group B streptococci. The reaction forms the basis of the CAMP test used to identify group B streptococci because the CAMP factor is believed to be restricted to this group of organisms. However, on occasion other streptococci, notably group A streptococci, may produce a similar synergistic lysis of sheep erythrocytes. The nature of the synergistic lytic factor of group A streptococci responsible for this sequential hemolysis was investigated in a tube CAMP reaction system. The properties of this synergistic lytic factor were found to correspond to those of streptolysin O of group A streptococci. The synergistic lytic factor, like streptolysin O, was produced during the logarithmic phase of growth; the activity was increased by reducing agents and greatly decreased or abolished by heat, trypsin, cholesterol, and anti-streptolysin O, and it was immunogenic in rabbits. This would suggest that the synergistic hemolysis seen in the CAMP reaction system with group A streptococci is due to the action of those small amounts of streptolysin O which remain unoxidized and thus have a capacity to lyse the fragile beta-lysin-treated sheep erythrocytes.
Proteus penneri and urinary calculi formation
Authors: Krajden S , Fuksa M , Lizewski W , Barton L , Lee A
Published: January 2020

The clinical significance of Proteus penneri, a newly described species, is unknown. A case report is presented, which is to the best of our knowledge the first description of this organism causing a urinary tract infection and bladder calculi.
Simple staining procedure permits rapid counting of mycoplasma colonies
Authors: Cluss R G , Somerson N L
Published: January 2020

A staining procedure employing oil red O and Coomassie R-250 was developed to increase visualization of mycoplasma colonies. This procedure permits CFU determination of mycoplasmas without additional microscopy.
Mycobacterium thermoresistibile infection in an immunocompromised host
Authors: Liu F , Andrews D , Wright D N
Published: January 2020

This is the second report of Mycobacterium thermoresistibile as the etiological agent of a pulmonary granuloma and the first occurrence of this organism in a patient who has not been outside the continental United States. The organism is susceptible to rifampin, ethambutol, and streptomycin but resistant to isoniazid and p-aminosalicylic acid.
Comparison of human fibroblast cells and primary rabbit kidney cells for isolation of herpes simplex virus
Authors: Moore D F
Published: January 2020

Human foreskin fibroblast cells and primary rabbit kidney cells were compared for efficiency in isolation of herpes simplex virus from 1,100 clinical specimens. Of the fibroblast cultures, 265 were positive, whereas 268 primary rabbit kidney cultures were positive. The results indicate that either cell type is acceptable for diagnostic use.
Detection of Streptococcus pneumoniae in lower respiratory tract specimens by anaerobic culture technique
Authors: Baesman R K , Strand C L
Published: January 2020

The relative efficacy of aerobic and anaerobic culture techniques for the recovery of Streptococcus pneumoniae from 1,173 lower respiratory tract specimens was determined. Unlike previous studies, this investigation found no significant difference between the two techniques.
Enhanced virus isolation by use of the transporter for a regional laboratory
Authors: Warford A L , Eveland W G , Strong C A , Levy R A , Rekrut K A
Published: January 2020

Transporter tubes with fibroblast monolayers were compared with sucrose-phosphate-glutamate buffer for transport of 385 specimens to a regional laboratory for virus culture. Ninety-two (91%) of 101 viral isolates were recovered in cell culture from the Transporter, as compared with 82 (81%) from sucrose-phosphate-glutamate buffer. Twenty-five (24.7%) of the viral isolates were detected by cytopathic effect from 1 to 11 days earlier from the Transporter than from the sucrose-phosphate-glutamate buffer. The Transporter also permitted the use of ambient temperature for transport.
Rapid detection of herpes simplex virus in clinical specimens with human embryonic lung fibroblast and primary rabbit kidney cell cultures
Authors: Callihan D R , Menegus M A
Published: January 2020

The performance of a culture system for isolation of herpes simplex virus, consisting of one tube each of human embryonic lung fibroblasts and primary rabbit kidney cells, was evaluated. Cultures were incubated at 37 degrees C on a roller drum and observed daily for characteristic cytopathic effect for 5 days. During 1982, a positive isolation rate of 28.1% was seen among 3,154 specimens submitted. Cultures from genital sources were positive more frequently from males (43.8%) than from females (25.5%). Oral lesion cultures were positive as often from males (34.6%) as from females (38.4%). Although detection of herpes simplex virus occurred significantly earlier in rabbit kidney cells on days 1 and 2 of incubation, by day 3 the number of positive cultures was nearly the same in both cell types. By day 4 of incubation, 99.5% of the positive cultures were detected. These results demonstrate that cell culture can be a rapid and sensitive method for detecting herpes simplex virus.
Recognition of whole Cryptosporidium oocysts in feces by negative staining and electron microscopy
Authors: Baxby D , Getty B , Blundell N , Ratcliffe S
Published: January 2020

Crytosporidium oocysts in feces were recognizable in the electron microscope when prepared by the negative staining technique used by virologists. Their size, shape, and surface markings were sufficiently characteristic for cryptosporidiosis to be diagnosed by this method if more suitable methods are not available.
Clinical laboratory differentiation of Legionellaceae family members with pigment production and fluorescence on media supplemented with aromatic substrates
Authors: Vickers R M , Yu V L
Published: January 2020

A systematic study of pigment production (browning) and fluorescence (extracellular yellow-green and intracellular blue-white) by nine Legionellaceae species was performed. A total of 56 strains representing Tatlockia micdadei (Pittsburgh pneumonia agent), Legionella pneumophila, Legionella jordanis, Legionella longbeachae, Legionella oakridgensis, Legionella wadsworthii, Fluoribacter bozemanae, Fluoribacter gormanii, and Fluoribacter dumoffii could be separated on media supplemented with tyrosine plus cystine, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, and 3-aminotyrosine. Parallel testing by hippurate hydrolysis and the bromocresol purple spot test enabled the identification of Legionellaceae species 24 to 72 h after primary isolation. This schema may be a practical alternative to species-specific antisera methods (slide agglutination or direct immunofluorescence) in the identification of members of the family Legionellaceae.
Evaluation of the rapid strep system for species identification of streptococci
Authors: Appelbaum P C , Chaurushiya P S , Jacobs M R , Duffett A
Published: January 2020

The Rapid Strep system (API System S.A., Montalieu-Vercieu, France) was evaluated, without additional tests, in the identification of 209 streptococci. Organisms included 59 beta-hemolytic, 36 group D, 24 Streptococcus pneumoniae, and 90 viridans group streptococci. The Rapid Strep system correctly identified to species level 69.5% of the beta-hemolytic strains, 100% of the group D strains, none of the S. pneumoniae strains, and 84.5% of the viridans group streptococci. The method provided excellent identification rates of groups A, B, and D but failed to differentiate between groups C and G. The method for preparation of suspensions for the Rapid Strep system, as initially recommended by the manufacturer, was responsible for the failure to identify S. pneumoniae. This method was subsequently modified to yield a heavier inoculum; all 10 pneumococcal strains tested with the revised inoculum method were correctly identified. Good identification rates of commonly encountered viridans strains were found. The Rapid Strep system represents a worthwhile advance in streptococcal species identification, especially for group D and viridans strains.
Rapid glutamic acid decarboxylase test for identification of Bacteroides and Clostridium spp
Authors: Jilly B J , Schreckenberger P C , LeBeau L J
Published: January 2020

A rapid 4-h test for glutamic acid decarboxylase is described for the identification of certain anaerobic bacteria. The test substrate consisted of 1.0 g of L-glutamic acid, 0.3 ml of Triton X-155, and 0.05 g of bromcresol green sodium salt in 1 liter of water. The substrate was dispensed in 0.5-ml amounts into test tubes, and a turbid suspension was made with the test organism. The test was then incubated aerobically at 35 degrees C for 4 h. The development of a blue color was considered positive. A total of 345 strains of clinically isolated anaerobic bacteria were tested. All isolates of Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides uniformis. Clostridium perfringens, and Clostridium sordellii gave a positive reaction. Some isolates of Bacteroides distasonis and Bacteroides vulgatus were also positive. The use of this rapid test in conjunction with other rapid methods, such as the spot indol test, will enable laboratory workers to report these pathogens on the same day on which an inoculum of pure culture growth on agar is available.
Detection of pneumococci in blood cultures by latex agglutination
Authors: Browne K , Miegel J , Stottmeier K D
Published: January 2020

Latex agglutination by use of the Pneumoslide test on clinical blood cultures detected 22 Streptococcus pneumoniae strains as the etiological agents in 47 streptococcal septic episodes. The other 25 isolates were identified as viridans streptococci or streptococci of groups A, B, D, or G. The test demonstrated 100% sensitivity, 92% specificity, and predictive values for positive and negative reactions of 91 and 92%, respectively. Two false-positive reactions were caused by strains of viridans streptococci. The two strains continued to give positive reactions when colonies from blood agar plates were tested according to the instructions of the manufacturer. This latex agglutination test is an effective tool for the rapid diagnosis of pneumococci in blood cultures.
Determination of plasmid-associated hydrophobicity of Yersinia enterocolitica by a latex particle agglutination test
Authors: Lachica R V , Zink D L
Published: January 2020

A quick and simple method was developed to distinguish hydrophobic from hydrophilic cells. The latex particle agglutination test is based on the hydrophobic interactions between cells and latex particles which result in the agglutination of the suspension mixture. There was a direct correlation between the expression of plasmid-associated cell surface properties and latex particle agglutination by Yersinia enterocolitica. Multivalent cation-induced agglutination of suspensions of washed cells of virulent Y. enterocolitica and latex particles is indicative of their amphipathic character. Electrostatic interaction may also play a role in the latex particle agglutination reaction.
Detection of specific immunoglobulin M antibody to different flaviviruses by use of enzyme-labeled antigens
Authors: Schmitz H , Emmerich P
Published: January 2020

An enzyme immunoassay was developed for the detection of human immunoglobulin M (IgM) antibody to different flavivirus antigens. The IgM antibody of human sera was selectively bound to anti-IgM antibody-coated solid-phase plates. Flavivirus IgM antibodies were then detected by use of various enzyme-labeled antigens. The flavivirus antigens (dengue type 2 virus, West Nile virus, and tick-borne encephalitis virus) were produced in suckling mice. The antigens were labeled with horseradish peroxidase by adding the activated enzyme at alkaline pH to sucrose-acetone-treated antigens. Addition of unlabeled mouse brain suspension of uninfected animals to the diluted enzyme-labeled antigens effectively reduced nonspecific binding to the solid phase. In patients with acute flavivirus infections, viral IgM antibody could be demonstrated with high sensitivity. Furthermore, the enzyme-labeled antigen-IgM test showed greater specificity than the hemagglutination inhibition test.
Outbreak of JK diphtheroid infections associated with environmental contamination
Authors: Quinn J P , Arnow P M , Weil D , Rosenbluth J
Published: January 2020

The group JK diphtheroid organism is a multiply resistant opportunistic pathogen which infects immunocompromised patients sporadically. We describe the first reported outbreak of JK diphtheroid infections, in which four cases of bacteremia and one Hickman catheter site infection occurred during 4 weeks on a hematology ward. On this ward, JK diphtheroid was recovered from 17 of 39 patients, 10 of 17 30-ft3 (0.840-m3) air samples, surfaces in 9 of 13 patient rooms, and hands of 4 of 22 personnel. Previously identified risk factors for JK diphtheroid sepsis (male gender, broad-spectrum antibiotic therapy, granulocytopenia, and prolonged hospital stay) were present in infected patients but did not distinguish them from patients who were only colonized. Emphasis on aseptic practices was associated with termination of the outbreak and negative hand cultures from personnel, despite continued patient colonization and environmental contamination.
Methodological aspects of Staphylococcus aureus peptidoglycan serology: comparisons between solid-phase radioimmunoassay and enzyme-linked immunosorbent assay
Authors: Christensson B , Espersen F , Hedström S A , Kronvall G
Published: January 2020

In the present studies we compared the ability of two commonly used assays, solid-phase radioimmunoassay and enzyme-linked immunosorbent assay (ELISA), to detect human antibodies to Staphylococcus aureus peptidoglycan. ELISA was superior, with a reproducibility of 12.0%, as compared with 18.1% in solid-phase radioimmunoassay. Much lower serum dilutions could be used in ELISA. We also studied the effects of solubilizing the antigen by lysostaphin, lysozyme, or ultrasonication. Lysostaphin-treated peptidoglycan cannot be recommended since solid-phase radioimmunoassay could not distinguish positive from negative serum samples with this preparation. On the other hand, the sensitivity in both assays was high when peptidoglycan treated with lysozyme for 240 min or with ultrasonication for 30 min was used as antigen. The interassay correlation between solid-phase radioimmunoassay and ELISA was slightly better with sonicated peptidoglycan (correlation coefficient = 0.94, P less than 0.01), as compared with lysozyme-treated peptidoglycan (correlation coefficient = 0.76, P less than 0.01). We recommend the ELISA with sonicated peptidoglycan as antigen for use in routine serology.
Comparison of rapid identification assays for Staphylococcus aureus
Authors: Aldridge K E , Kogos C , Sanders C V , Marier R L
Published: January 2020

A total of 137 strains of Staphylococcus species were blindly tested by four rapid serological assays, and the results were compared with those of the tube coagulase assay. For the S. aureus isolates, the Sero-STAT Staph assay gave six false-negative results, four of which were for methicillin-resistant strains. The Accu -Staph, Staphylatex , and Staphyloslide assays identified all the coagulase-positive strains as Staphylococcus aureus. Among the coagulase-negative staphylococci, false-positive results were seen with strains of S. capitis. S. saprophyticus, and S. cohnii. The overall accuracy of the kits compared with the tube coagulase test ranged from 95.1 to 100%.
Recovery and susceptibility testing of Mycobacterium tuberculosis from extrapulmonary specimens by the BACTEC radiometric method
Authors: Fadda G , Roe S L
Published: January 2020

This study was carried out to evaluate the sensitivity and rapidity of the BACTEC radiometric techniques for isolation and susceptibility testing of mycobacteria from extrapulmonary specimens. Concentrated specimens of urine, pleural fluid, and blood as well as other extrapulmonary specimens were processed for the recovery of mycobacteria and for drug susceptibility testing, employing conventional and BACTEC radiometric methods. Out of 483 specimens processed, 20 were found to be positive for Mycobacterium tuberculosis on the conventional Lowenstein -Jensen medium, and 19 were found to be positive in the BACTEC 7H12 medium. Average recovery times were 22.5 days for the conventional method and 10.9 days for the BACTEC method. When isolated cultures were tested for susceptibility to streptomycin, isoniazid, rifampin, and ethambutol, results were reported at an average time of 22 and 5.4 days for the conventional and BACTEC methods, respectively, with good correlation.
Development of an enzyme-linked immunosorbent assay for studying Pseudomonas aeruginosa cell surface antigens
Authors: Borowski R S , Stock L M , Schiller N L
Published: January 2020

An enzyme-linked immunosorbent assay for the measurement of antibodies directed against Pseudomonas aeruginosa cell surface antigens was developed. Formalin-killed whole cells of P. aeruginosa, adsorbed to polystyrene acrylic copolymer cuvettes, were used as immobilized antigens. Antisera to P. aeruginosa mucoid strain 144M and to its spontaneous nonmucoid derivative, 144NM, were raised in rabbits by immunization with Formalin-killed bacteria. By using this enzyme-linked immunosorbent assay, anti-144M serum was found to have a ca. 10-fold-higher antibody titer to 144M than did anti-144NM serum, suggesting that 144M may have either immunogenic determinants not present on 144NM or perhaps simply more antigenic determinants. In contrast, anti-144M and anti-144NM immune sera were found to have nearly identical antibody titers to 144NM, suggesting that these strains share many determinants. Anti-P. aeruginosa immune serum was found to contain Pseudomonas-specific antibodies as well as antibodies which cross-reacted with other gram-negative bacteria. Finally, absorption studies demonstrated that this assay can detect both LPS and non-LPS surface-exposed antigenic determinants. Thus, this whole bacterial cell enzyme-linked immunosorbent assay should prove useful in monitoring patient sera and secretions for potentially protective immunoglobulins directed at P. aeruginosa cell surface antigens.
Rapid antimicrobial susceptibility testing of Gram-negative clinical isolates with the AutoMicrobic system
Authors: Backes B A , Cavalieri S J , Rudrik J T , Britt E M
Published: January 2020

Comparisons of the antimicrobial susceptibility patterns of clinical isolates of the family Enterobacteriaceae and Pseudomonas aeruginosa were made by using Kirby-Bauer disk diffusion, the MicroMedia system broth microdilution, and the AutoMicrobic system. The Kirby-Bauer system compared favorably with the MicroMedia system (95% essential correlation with 90% complete agreement). The AutoMicrobic system also compared favorably with both the Kirby-Bauer system (93% essential correlation with 87% complete agreement) and the MicroMedia system (97% essential correlation with 85% complete agreement). These data indicate that the AutoMicrobic system results are comparable to those of the MicroMedia and the Kirby-Bauer systems. Furthermore, the AutoMicrobic system offers a more rapid system (6 to 10 h), than the traditional systems, without sacrificing accuracy (16 to 24 h).
Efficiency of human rotavirus propagation in cell culture
Authors: Ward R L , Knowlton D R , Pierce M J
Published: January 2020

This study was designed to find methods to reproducibly propagate human rotaviruses from fecal specimens and to determine the relationship between particle numbers and infectivity. Growth of virus was initially compared in primary and continuous lines of monkey kidney cells. Primary cells (African green and cynomolgus monkey kidney) supported virus growth directly from fecal specimens much more efficiently than did continuous lines of African green (CV-1) or rhesus (MA104) monkey kidney cells. Rotaviruses were grown in primary cells from 14 of 14 fecal specimens of different individuals collected over a 3-year period. Although rotaviruses in fecal samples could not always be grown in the continuous cell lines, two passages in primary cells appeared to fully adapt the viruses for propagation in the continuous cell line tested (MA104). The efficiency of rotavirus growth was quantified with five of the fecal isolates. It was calculated that, on the average, 1 out of every 46,000 particles in fecal specimens infected monkey kidney cells. After three passages in primary cells, an average of 1 out of every 6,600 progeny virus particles appeared to be infectious. Thus, rotaviruses in fecal specimens were consistently grown in primary cells, and passage in these cells both increased virus infectivity and adapted the viruses for growth in continuous cell lines.
Comparative evaluation of commercial fluorescent treponemal antibody-absorbed test kits
Authors: Beebe J L , Nouri N J
Published: January 2020

We describe a comparative evaluation of commercial fluorescent treponemal antibody-absorbed test kits, using 150 selected patient sera. The ability of the test kits to detect reactive sera varied from 82.5 to 95%; that for nonreactive sera varied from 80.9 to 96.4%. Reproducibility of reactive and nonreactive results, measured by between-assay and within-assay studies, averaged 42%. The results showed substantial variation in performance characteristics among the kits, with important clinical implications for the diagnosis of syphilis. We recommend the development of an immunological standard for use in the manufacture of fluorescent treponemal antibody-absorbed test kits, with the goal of obtaining uniform performance characteristics among commercial test kits.
Lymphoid cell blastogenesis as an in vitro indicator of cellular immunity to Legionella pneumophila antigens
Authors: Friedman F , Widen R , Klein T , Friedman H
Published: January 2020

The lymphocyte blastogenic transformation assay was adapted to study responsiveness of lymphoid cells from animals and humans to Legionella pneumophila antigens in vitro. Spleen cells from guinea pigs after active immunization with Legionella vaccine, but not from normal animals, responded by blast cell transformation when stimulated in vitro with killed Legionella whole-cell vaccine, sonic extracts thereof, or a purified somatic antigen. The response was dose dependent. Similar lymphocyte blastogenesis occurred with spleen cells from mice sensitized to Legionella by sublethal infection with the bacteria. In addition, blastogenesis occurred with peripheral blood leukocytes from human volunteers tested in vitro with whole-cell vaccine, sonic extracts, or purified somatic antigen. Maximum responsiveness generally occurred 4 to 5 days after stimulation of human peripheral blood leukocytes, but a day or two earlier with spleen cells from normal or sensitized mice. Guinea pig spleen cells generally showed peak responses at the same time as human peripheral blood leukocytes after stimulation in vitro. Blastogenic responses with purified antigen were comparable to those with the whole-cell vaccine or sonic extract. Such antigens from Legionella provide a useful material for inducing responses in vitro as a correlate of cellular immunity to these bacteria.
Comparison of various methods for differentiation of staphylococci and micrococci
Authors: Baker J S
Published: January 2020

A modified oxidase test (Remel, Lenexa, Kans.) and susceptibility to furazolidone and lysostaphin (Remel) were evaluated in conjunction with the Staph-Ident strip (Analytab Products, Plainview, N.Y.) to accurately differentiate between staphylococci and micrococci. A total of 414 clinical isolates of catalase-positive, gram-positive cocci were each tested with the Staph-Ident strip and by glucose fermentation, acid production from glycerol, susceptibility to furazolidone and lysostaphin, and the oxidase test. Based on the reference methods of glucose fermentation and acid production from glycerol, 396 (95.6%) of the organisms were classified as Staphylococcus species and 18 (4.4%) were classified as Micrococcus species. Of the staphylococci, 99% were oxidase negative and susceptible to furazolidone; 82% were susceptible to lysostaphin. All of the micrococci were oxidase-positive and resistant to furazolidone and lysostaphin. Of the staphylococci, 99% were identified to species by the Staph-Ident strip. However, six (33%) of the micrococci were incorrectly identified as Staphylococcus species (three each of Staphylococcus hominis and Staphylococcus saprophyticus). Because of the demonstrated sensitivity and specificity of the oxidase and furazolidone susceptibility tests, it is suggested that either of these methods be used in the clinical laboratory to accurately differentiate between staphylococci and micrococci. It is also suggested that when working with the Staph-Ident strip, additional testing such as furazolidone susceptibility or oxidase activity should be performed to provide increased accuracy in the differentiation and characterization of members of the family Micrococcaceae.
Production of bacteriocin-like inhibitors by group A streptococci of nephritogenic M types
Authors: Tagg J R
Published: January 2020

Application of a bacteriocin-typing scheme that had been designed to minimize the inhibitory effects of hydrogen peroxide and acidic metabolites demonstrated a high incidence (72%) of bacteriocin-like inhibitors belonging to 5 different production (P) types in 61 strains of group A streptococci isolated in association with the development of acute glomerulonephritis. By contrast, only 4 of 16 (25%) rheumatic fever-associated strains were inhibitor positive, and 3 of these strains were P type 604, a P type not detected in any of the nephritis isolates. The P type designation was found to be identical for all inhibitor-positive strains within each particular M serotype, regardless of whether the source was a nephritis patient or an individual having an uncomplicated streptococcal infection. The incidence of inhibitor-positive strains was particularly high in strains of M types 2, 4, 12, 25, 57, and 60; it was moderately high in M types 49, 52, and 55 and absent in M1 and M3. Although the results indicate that the bacteriocin-like inhibitors detected in this study are probably unlikely to have a direct pathogenetic role in either rheumatic fever or acute glomerulonephritis, it does seem that the present P-typing scheme is a useful epidemiological tool, particularly for the presumptive identification of and differentiation among group A streptococcus strains of nephritogenic serotypes.
Comparison of Transgrow and Gonozyme for the detection of Neisseria gonorrhoeae in mailed specimens
Authors: Martin R , Wentworth B B , Coopes S , Larson E H
Published: January 2020

The Transgrow culture system and Gonozyme (Abbott Laboratories, North Chicago, Ill.), an enzyme-linked immunosorbent assay procedure, were compared by examining 510 patients (320 females, 190 males) from whom duplicate genital swabs were obtained for the diagnosis of Neisseria gonorrhoeae infection. Both Transgrow and the Gonozyme swabs were mailed to the laboratory. Clinical, epidemiological, and laboratory data for the 30 specimens for which there were discrepancies were evaluated to determine the probability of gonorrhea. At the same time, Gonozyme was compared to on-site Thayer-Martin cultures from 258 of the 510 patients, with a 93% agreement. When sensitivity and specificity were calculated on the basis of clinical, epidemiological, and on-site laboratory data, Gonozyme had a sensitivity of 95% and a specificity of 99%. Transgrow culture was considered to have a 100% specificity and a sensitivity of 69%. Gonozyme appeared to be a superior method for the diagnosis of gonorrhea by means of mailed specimens.
New principle for the simultaneous detection of total and immunoglobulin M antibodies applied to the measurement of antibody to hepatitis B core antigen
Authors: Angarano G , Monno L , Santantonio T A , Pastore G
Published: January 2020

A new test principle for the simultaneous detection of total approximate titers and immunoglobulin M antibodies has been developed and applied to the detection of antibody to hepatitis B core antigen. The method is based on the combination of a competition radioimmunoassay, for the determination of total antibody titer, with an indirect enzyme-linked immunosorbent assay for the determination of single class antibodies. The interference of the rheumatoid factor was avoided by including heat-aggregated immunoglobulin G in the dilution buffer. The specificity, sensitivity, and clinical application of the test are discussed. The results presented suggest that the simultaneous detection of total and immunoglobulin M antibody to hepatitis B core antigen might be helpful in the differentiation between previous and recent or ongoing hepatitis B infection, as well as in the differential diagnosis of acute hepatitis, in monitoring viral activity in chronic infections, and in helping to differentiate acute from chronic infections. The test principle appears applicable in the accurate diagnosis of other infectious diseases by a single test on only one serum sample.
Morphology of bacterial attachment to cardiac pacemaker leads and power packs
Authors: Marrie T J , Costerton J W
Published: January 2020

The mode of growth of the bacteria adherent to the surfaces of various components of cardiac pacemakers infected with coagulase-negative staphylococci was examined by scanning and transmission electron microscopy. Within developing adherent microcolonies, coccoid cells could be clearly seen to be enveloped by an amorphous material that condensed radically upon dehydration for electron microscopy, producing an amorphous residue in scanning electron micrographs and a fibrous anionic ruthenium red-staining residue in transmission electron micrographs. The differences in morphologies of the condensed residues may reflect differences in exopolysaccharides elaborated by the microorganisms and the degree to which materials of host origin are incorporated. The coccoid cells of coagulase-negative staphylococci were less clearly seen in thick, mature, adherent biofilms on heavily colonized surfaces because the condensed residue of their exopolysaccharide glycocalyces covered, and sometimes occluded, the bacteria cells. These coagulase-negative staphylococcal strains appeared to produce more exopolysaccharide material than did the strains infecting various intravascular catheters.
Evaluation of the 24-h API 20A anaerobe system for identification of Clostridium difficile
Authors: Gresser M E , Shanholtzer C J , Gerding D N , Garrett C R , Peterson L R
Published: January 2020

Accurate identification of Clostridium difficile is important when antibiotic-associated diarrhea or pseudomembranous colitis is suspected. Presumptive identification of C. difficile was made on the basis of microscopic features and colony characteristics on cycloserine, cefoxitin, fructose, and egg yolk agar medium. We studied the reliability of the 24-h API 20A anaerobe system for definitive identification of C. difficile. This system showed low dependability after the recommended 24 h of incubation by confirming the identity of only 54% of the isolates presumptively identified as C. difficile. There was a marked improvement in the system's capability after 48 h of incubation, when the identity of 95% of the isolates was confirmed.
Rapid detection of cytomegalovirus in MRC-5 cells inoculated with urine specimens by using low-speed centrifugation and monoclonal antibody to an early antigen
Authors: Gleaves C A , Smith T F , Shuster E A , Pearson G R
Published: January 2020

A commercially available monoclonal antibody directed against an early nuclear protein of cytomegalovirus was used with low-speed centrifugation for the rapid detection of this virus from urine specimens inoculated onto MRC-5 cells. A total of 19 of 162 (11.7%) urine specimens inoculated were positive by both immunofluorescence and peroxidase-antiperoxidase procedures (sensitivity, 100%), whereas only 18 of the samples produced cytopathic effects in conventional cell culture (specificity, 94.7%). All specimens were positive by immunofluorescence and peroxidase-antiperoxidase procedures at 36 h postinfection, whereas an average of 9 days was required for cytopathic effects to develop in cell cultures.
Comparison of Cultureset and primary rabbit kidney cell culture for the detection of herpes simplex virus
Authors: Rubin S J , Rogers S
Published: January 2020

Herpes simplex virus isolation by conventional cell culture in primary rabbit kidney cells (RK) was compared with Cultureset (CS). At 24 h CS was more sensitive (31 versus 25 of 55 isolates detected) than RK, but at 48 h there was little difference (43 detected by CS, 46 by RK). CS stained at 48 h was significantly less sensitive (78.2%) than RK observed for 1 week. CS stained at 24 or 48 h was not an acceptable substitute for RK observed for 1 week.
Semisolid selective-motility enrichment medium for isolation of salmonellae from fecal specimens
Authors: Goossens H , Wauters G , de Boeck M , Janssens M , Butzler J P
Published: January 2020

A semisolid selective-motility enrichment medium for the isolation of salmonellae from fecal specimens was developed which was based on Rappaport enrichment broth. During a 7-year period more than 30,000 stool samples were tested. The medium showed a high specificity (95.1%) and sensitivity (80.3%) when compared with MacConkey agar, SS agar, and brilliant green agar (after Selenite-F Enrichment [BBL Microbiology Systems]). Furthermore, our isolation rate of Salmonella species from fecal samples showed an increase of 22.3% when this semisolid medium was added to the routine culture media. Growth could easily be interpreted. The medium has a bias toward the isolation of Salmonella paratyphi B, but it is unsatisfactory for detecting the nonmotile strains Salmonella typhi and S. paratyphi A.
Bacteremia caused by Achromobacter species in an immunocompromised host
Authors: Kish M A , Buggy B P , Forbes B A
Published: January 2020

A case of bacteremia caused by Achromobacter species in an immunocompromised patient is described. The patient responded to antibiotic therapy. Detailed antibiotic susceptibility data are presented.
Evaluation of the Culturette Brand Ten-Minute Group A Strep ID technique
Authors: Slifkin M , Gil G M
Published: January 2020

A direct extraction of the antigens of group A beta-hemolytic streptococci from 557 throat swabs was performed by a new microtechnique of the nitrous acid extraction method with the Culturette Brand Ten-Minute Strep ID technique from Marion Scientific, Division of Marion Laboratories, Inc., Kansas City, Mo. This group A latex reagent kit contains the reagents for the micronitrous acid extraction of throat swabs and does not require a centrifugation step in its protocol. There was a 99.3% (553 of 557) total agreement between the direct nitrous acid extraction-latex agglutination method and the standard culture method. The direct extraction method yielded an identification of 95.1% (78 of 82) of the group A streptococci identified by the standard method. Throat swabs used for standard culture may also be extracted with nitrous acid for the detection of group A antigen. A 5-min nitrous acid extraction destroys the viability of bacteria associated with normal throat flora as well as group A streptococci and Mycobacterium tuberculosis. This highly rapid method is simple to perform and requires no costly instrumentation. Accordingly, it would be most applicable in a hospital laboratory as well as in a physician's office.
Evaluation of the virocult transport tube for isolation of herpes simplex virus from clinical specimens
Authors: Johnson F B , Leavitt R W , Richards D F
Published: January 2020

Herpes simplex virus survived in Virocult transport tubes and had a half-life of 3.5 days at 2 degrees C and 2.75 days at 22 degrees C. Of 2,000 consecutive clinical specimens transported on Virocult tubes and cultured for herpes simplex virus, 448 (22.4%) were positive. Comparison of the holding times between positive and negative cultures, up to 12 days, revealed no significant loss of positive cultures with time.
Microneutralization test in PK(15) cells for assay of antibodies to louping ill virus
Authors: Timoney P J , Geraghty V P , Harrington A M , Dillon P B
Published: January 2020

A microneutralization test in PK(15) cells was developed to measure the neutralizing antibody response of a group of ponies experimentally challenged with louping ill virus. Viral cytopathic effect was maximal after 6 days of incubation, at which point titration endpoints were clear-cut and readily determinable. The assay compared favorably with the mouse neutralization test for accuracy and ease of performance.
Simple screening method for beta-lactamase-positive and -negative ampicillin-resistant Haemophilus influenzae isolates
Authors: Parr T R , Pai C H , Bryan L E
Published: January 2020

A simple, inexpensive method for screening for beta-lactamase-positive and beta-lactamase-negative ampicillin-resistant Haemophilus influenzae isolates was developed. Disks containing 10 micrograms of cloxacillin yielded no zone of inhibition when placed on chocolate agar plates inoculated with beta-lactamase-positive (16 strains) or ampicillin-resistant (greater than or equal to 1 microgram/ml) beta-lactamase-negative (10 strains) H. influenzae, whereas ampicillin-susceptible (less than or equal to 0.5 microgram/ml; 36 strains) H. influenzae almost always (92%) showed a zone of inhibition.
Use of a Single-Tube Medium,
o
-Nitrophenyl-β-
d
-Galactopyranoside-Phenylalanine-Motility Sulfate, for Screening of Pathogenic Members of the Family
Enterobacteriaceae
Authors: Thompson J. Stephen , Borczyk Alexander A.
Published: January 2020

A single-tube, multiple-test medium for the screening of
Enterobacteriaceae
in enteric and other clinical specimens is described. This medium allows the detection of motility, β-galactosidase and phenylalanine deaminase activities, and H
2
S and indole production.
Endotoxin in middle-ear effusions from patients with chronic otitis media with effusion
Authors: DeMaria T F , Prior R B , Briggs B R , Lim D J , Birck H G
Published: January 2020

Endotoxin concentrations were determined in middle-ear effusions (MEEs) from 89 children with chronic otitis media by using the Limulu's amoebocyte lysate assay. Mean concentrations of endotoxin in Haemophilus influenzae-positive and Streptococcus pneumoniae-positive MEEs were 157 and 21.8 ng/ml, respectively, and were significantly different (P less than 0.01). Endotoxin was also found in Gram stain-positive, culture-negative and Gram stain-negative, culture-negative MEEs, but the levels were not significantly different (P greater than 0.05). However, the endotoxin concentrations in both groups of culture-negative MEEs significantly lower than those found in MEEs that grew either H. influenzae or S. pneumoniae (P less than 0.05). These results show that endotoxin is present in a high percentage of human MEEs, including those that are culture negative, and may contribute to the pathogenesis of otitis media with effusion.
Rapid screening assay for toxic shock syndrome toxin production by Staphylococcus aureus
Authors: Weckbach L S , Thompson M R , Staneck J L , Bonventre P F
Published: January 2020

A rapid immunoblot assay (TST-blot) was developed and used to screen Staphylococcus aureus isolates for toxic shock syndrome toxin (TST) production. Growth from an 18-h stab inoculum of S. aureus on brain heart infusion agar was transferred directly to a nitrocellulose sheet. Nonspecific protein binding sites were blocked with bovine serum albumin, and the nitrocellulose sheet was incubated with affinity-purified antibody to TST, followed by incubation with horseradish peroxidase-conjugated protein A. Toxin was visualized by detection of the peroxidase-conjugated protein A-anti TST-TST complex with 4-chloro-1-napthol. The sensitivities and specificities of the TST-blot and Ouchterlony microslide immunodiffusion assay were compared by screening 141 S. aureus isolates for TST production. In both assays, 53 of 141 isolates produced detectable levels of TST, whereas 88 isolates produced no toxin. A 100% concordance was found between the two assays. The TST-blot yielded the same results in less than 24 h as those yielded by the 3-day immunodiffusion assay. Thus, this rapid method for detection of TST in multiple samples appears to be well suited for diagnostic and epidemiological studies. Furthermore, it would appear to be ideal for use in TST genetics research.
Pathogenic properties of Escherichia coli strains isolated from diarrheic commercial rabbits
Authors: Peeters J E , Pohl P , Okerman L , Devriese L A
Published: January 2020

Thirty-two different strains of Escherichia coli isolated from diarrheic commercial rabbits showing intestinal attachment of bacilli were studied. None of the strains produced thermostable or thermolabile enterotoxins, and none was invasive. Strains isolated from suckling rabbits attached in vitro to the brush borders of intestinal villi, whereas strains from weanling rabbits did not. After experimental infection of 5-week-old rabbits, the 26 strains isolated from weaned diarrheic rabbits attached to the epithelium of ileum, cecum, and colon, whereas only slight attachment was found after infection with the six strains isolated from suckling diarrheic rabbits. The former strains induced diarrhea in 87% of the rabbits, whereas the latter induced diarrhea in only 9% of inoculated rabbits. E. coli isolated from healthy rabbits did not cause diarrhea. Strains isolated from diarrheic suckling rabbits all belonged to serotype O109:K-:H2, whereas strains from diarrheic weaned rabbits belonged to at least eight different serogroups. It is suggested that two different mechanisms of E. coli enteropathy might exist in rabbits.