bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection of nonfastidious adenovirus species in 293 cells inoculated with stool specimens containing adenovirus 40
Authors: Brown M
Published: January 2020

Of 35 stool specimens isolated and examined in 293 cells, 15 isolates contained adenovirus species 40 (Ad40), and 4 of these 15 isolates also contained a nonfastidious adenovirus species (Ad1 in two cases, Ad18 or Ad31) which was selected over Ad40 during serial passage in the 293 cells. The selection of Ad1 over Ad40 was examined in detail. Restriction analysis of intracellular DNA and the relative infectivity titers of Ad40 and Ad1 at each passage level after the inoculation of 293 cells with a particular stool specimen demonstrated that although the amount of Ad40 DNA synthesized far exceeded that of Ad1, the relative infectivity titer of Ad40 was low. The growth characteristics of Ad40 were then compared with those of Ad1, Ad18, and Ad41 in singly infected 293 cell cultures. One-step growth curves showed the same growth rate in each case, with a latent period of 12 h and a maximum titer at 24 to 36 h postinfection. Yields of infectious Ad40 virus were consistently 100- to 1,000-fold lower than those of Ad1. This difference was reflected by a reduced yield of total AD40 virions (p1.34) as determined by 35S labeling experiments. However, the 3- to 10-fold reduction in total yield of Ad40 virions did not account for the 100- to 1,000-fold reduction in the yield of infectious virus.
Antimicrobial susceptibility testing of Francisella tularensis with a modified Mueller-Hinton broth
Authors: Baker C N , Hollis D G , Thornsberry C
Published: January 2020

A modified Mueller-Hinton broth was developed to perform antimicrobial susceptibility tests on Francisella tularensis. Adequate growth of the organism was obtained within 24 h of inoculation, and MICs could be read at that time. We tested 15 selected strains of F. tularensis and five reference quality control strains in this medium with 36 antimicrobial agents. The MICs of the aminoglycosides and tetracycline increased 1 to 3 dilutions in this medium compared with those in the usual medium, but the other antimicrobial agents were not consistently affected by the medium. Even though the medium caused an increase in MICs, the aminoglycosides and tetracyclines remained very active in vitro against F. tularensis. Other antimicrobial agents effective in vitro were chloramphenicol, erythromycin, ceftazidime, moxalactam, cefotaxime, ceftriaxone, and Sch 29482 (a cephalosporin).
Detection of Treponema pallidum in lesion exudate with a pathogen-specific monoclonal antibody
Authors: Hook E W , Roddy R E , Lukehart S A , Hom J , Holmes K K , Tam M R
Published: January 2020

The diagnosis of early syphilis currently requires dark-field microscopic or serologic demonstration of Treponema pallidum infection. Dark-field microscopy is not widely available and is complicated by the numerous saprophytic spirochetes which are present at oral and rectal mucosal surfaces. Serologic tests are positive in only 70 to 90% of patients with primary syphilis, and several days may be required for results to become available. We used a pathogen-specific, fluorescein-conjugated monoclonal antibody to examine lesion exudates from 61 patients for the presence of T. pallidum and compared the data with results of dark-field microscopy and serologic testing. The direct fluorescent-antibody technique revealed the presence of T. pallidum in 30 of 30 patients with early syphilis, and dark-field microscopy was positive for 29. Serologic tests were reactive for 27 of 30 patients with syphilis; in the 3 patients with nonreactive serologic tests, chancres had been present for 4, 6, and 21 days. Although 7 of 31 patients without syphilis had spiral organisms seen on dark-field microscopy, the direct fluorescent-antibody test was negative for all 31. The presence of nonpathogenic spirochetes was subsequently verified in 5 of 7 patients by using a second monoclonal antibody which reacts with nonpathogenic, as well as pathogenic, treponemes and related spirochetes. The demonstration of T. pallidum by using fluorescein-conjugated monoclonal antibodies is intrinsically specific and is as sensitive as dark-field microscopy for the diagnosis of early syphilis. This method provides a convenient, accurate means for the diagnosis of syphilis by health care providers, many of whom lack access to dark-field microscopy.
Simplified plaque reduction neutralization assay for dengue viruses by semimicro methods in BHK-21 cells: comparison of the BHK suspension test with standard plaque reduction neutralization
Authors: Morens D M , Halstead S B , Repik P M , Putvatana R , Raybourne N
Published: January 2020

A newly modified semimicro plaque reduction neutralization test (PRNT) in BHK cells was compared with a standard PRNT in bottles with LLC-MK2 monolayers and with an LLC-MK2 PRNT adapted to semimicro methods. The BHK semimicro PRNT compared favorably in terms of sensitivity in detecting dengue antibody (96%), specificity at a screening dilution (95%), and ability to detect seroconversion to dengue viruses of three serotypes (93%). Disagreements between the BHK test and the LLC-MK2 tests were attributed to greater sensitivity of the BHK test in detecting dengue type 2 (DEN-2) antibody in acute-phase sera and to apparent low-level DEN-1/DEN-3 cross-reactions in some sera in all three tests. The BHK PRNT was easier, faster, and more economical than either of the LLC-MK2 tests. Many of the benefits of the BHK PRNT derive from the fact that cells are infected while still in suspension, at the time of cell splitting, hence the term "BHK suspension test."
Retrospective evaluation of the isolation and identification of herpes simplex virus with Cultureset and human fibroblasts
Authors: Phillips L E , Magliolo R A , Stehlik M L , Whiteman P A , Faro S , Rogers T E
Published: January 2020

A total of 442 specimens from various anatomic sites was cultured for herpes simplex virus during the past 2 years. Most specimens were obtained from the respiratory tracts and cutaneous lesions of immunocompromised hosts (232 specimens) or the female genital tract (138 specimens). Two tubes containing human newborn foreskin fibroblasts and two Ortho Cultureset tubes containing Vero cells were inoculated with each specimen. The 384 inoculated specimens were stained with Cultureset peroxidase-antiperoxidase reagents within 48 h and again at 3, 4, or 5 days if initially negative. Fibroblasts were inspected for cytopathic effect for 7 days. Of these 384 specimens, Cultureset detected 57 of 62 positive specimens within 48 h; fibroblasts detected 58 positive specimens by 7 days. The calculated sensitivity and specificity for Cultureset at 48 h were 91.9 and 100%, respectively. However, when all results were considered, including those that became positive in Cultureset after 48 h, the calculated sensitivity and specificity for Cultureset were 98.8 and 100%, respectively. We conclude that Cultureset is a reliable method for detection of herpes simplex virus when two tubes are inoculated and stained as described.
Specific enzyme-linked immunoassay for rotavirus serotypes 1 and 3
Authors: Shaw R D , Stoner-Ma D L , Estes M K , Greenberg H B
Published: January 2020

We prepared monoclonal antibodies against two serotypically distinct rotavirus strains: Wa, a serotype 1 virus of human origin, and rhesus rotavirus, a simian serotype 3 virus. Monoclonal antibodies which react specifically with VP7 of each serotype were identified by hemagglutination inhibition tests, plaque reduction neutralization studies, and solid-phase immunoassays which used wild-type and reassortant strains of rotavirus. An enzyme-linked immunoassay was designed which utilizes two of these antibodies to correctly identify serotype 1 and serotype 3 viruses.
Specimen volume versus yield in the BACTEC blood culture system
Authors: Plorde J J , Tenover F C , Carlson L G
Published: January 2020

During a 24-month period, 5,625 blood culture specimens were collected at the Seattle Veterans Administration Medical Center in 20-ml volumes and divided into separate 10-ml aliquots. The two aliquots were processed as duplicate sets (set 1, set 2) by the BACTEC system (Johnston Laboratories, Inc., Towson, Md.). Specimens (5 ml) from each set were inoculated into aerobic (6B) and anaerobic (7C/7D) vials. A total of 434 significantly positive blood cultures were found. In 342 of these positive cultures, yielding 379 isolates (112 members of the family Enterobacteriaceae, 104 staphylococci, 87 streptococci, 27 anaerobes, 20 yeasts, 14 pseudomonads, and 15 miscellaneous organisms), there was adequate specimen volume to fill all four vials. The utilization of set 1 would have resulted only in the failure to detect 65 of 379 (17.2%) significant isolates, 52 of 342 (15.2%) positive cultures, and 20 of 198 (10.1%) bacteremic episodes. There were no significant differences in the recovery of individual species in sets 1 and 2. Although the range of isolates recovered by the aerobic and anaerobic vials of each set differed, the percent yield of total isolates was similar, indicating total isolate yield was predominantly a function of specimen volume. The addition of set 2 most dramatically increased the recovery of Escherichia coli (30%), yeasts (33%), and anaerobes (42%).
Spontaneous occurrence of Staphylococcus aureus mutants with different pigmentation and ability to produce toxic shock syndrome toxin 1
Authors: Lee A C , Bergdoll M S
Published: January 2020

Spontaneous mutants that have pigmentation different than that of their parents were isolated from three Staphylococcus aureus strains associated with toxic shock syndrome. These mutants produced toxic shock syndrome toxin 1 in amounts varying from less than 0.05 to greater than 25 times that produced by the parents. The occurrence of nonpigmented variants may be overlooked if only one isolate from a patient with toxic shock syndrome is selected for analysis.
Proposed disk diffusion susceptibility criteria for ofloxacin
Authors: Fuchs P C , Barry A L , Jones R N , Thornsberry C
Published: January 2020

Disk diffusion zone diameter breakpoint criteria for ofloxacin were tentatively established by correlating MICs with 1-, 3-, and 5-micrograms disk inhibitory zone diameters for 638 bacterial isolates representing 36 species. We recommend use of 5-micrograms disks with the following breakpoints: susceptible (MIC, less than or equal to 2.0 micrograms/ml), greater than or equal to 16 mm; intermediate (MIC, 4.0 micrograms/ml), 13 to 15 mm; and resistant (MIC, greater than or equal to 8.0 micrograms/ml), less than or equal to 12 mm.
Isolation of Mycobacterium paratuberculosis from intestinal mucosa and mesenteric lymph nodes of goats by use of selective Dubos medium
Authors: Saxegaard F
Published: January 2020

To isolate Mycobacterium paratuberculosis from contaminated material, a selective medium, selective Dubos medium (SDubos), was developed by supplementing conventional Dubos medium (CDubos) with carbenicillin, polymyxin, trimethoprim, and amphotericin B. The intestine and mesenteric lymph nodes of 1,501 goats were cultured in parallel on SDubos and CDubos after decontamination with oxalic acid. The contamination rate was reduced more than 150 times by the use of SDubos. The number of positive specimens (18, or 1.2%), i.e., those which revealed growth of M. paratuberculosis, was too small to evaluate the number of specimens which could have been missed due to contamination on CDubos. However, the number of specimens positive on SDubos (16, or 89%) showed that the antibiotics used were not harmful to M. paratuberculosis.
Isolation of Yersinia enterocolitica biotype 4 serotype O3 from canine sources in Italy
Authors: Fantasia M , Grazia Mingrone M , Crotti D , Boscato C
Published: January 2020

Seventeen strains of Yersinia enterocolitica biotype 4 serotype O3 were isolated from 63 apparently healthy puppies. Of these strains, 76.4% showed both multiple resistance to antimicrobial agents and lack of sorbose fermentation.
Leptotrichia buccalis bacteremia in neutropenic children
Authors: Reig M , Baquero F , García-Campello M , Loza E
Published: January 2020

Two new cases of Leptotrichia buccalis bacteremia in seriously ill patients were described. The anaerobic, gram-negative microorganism L. buccalis was isolated from blood cultures of two children with severe leukopenia. Anaerobic organisms should be taken into account when a standard protective antibiotic chemotherapy is considered in the immunosuppressed host.
Competitive enzyme immunoassays for the rapid detection of antibodies to feline infectious peritonitis virus polypeptides
Authors: Fiscus S A , Teramoto Y A , Mildbrand M M , Knisley C V , Winston S E , Pedersen N C
Published: January 2020

Monoclonal antibodies specific for the envelope (E1), peplomer (E2), and nucleocapsid (N) polypeptides of feline infectious peritonitis virus (FIPV) were used in rapid, competitive enzyme-linked immunosorbent assays (ELISA) to study the humoral immune response of cats to FIPV infection. Results from the competitive ELISAs were correlated with those from immunofluorescent antibody assays (IFAs) on 203 samples obtained from 64 individual cats. The IFA results correlated best with those obtained with the anti-E1 specific competitive ELISA (85.7%). In contrast, anti-N and anti-E2 competitive ELISA results correlated with IFA results only 65.5 and 2.4% of the time, respectively. The results of the anti-E1 specific competitive ELISA were not influenced by the total immunoglobulin concentration or the possible presence of free viral antigens in the serum. These results suggest that a competitive ELISA involving the use of enzyme-conjugated monoclonal antibody to the E1 glycoprotein of FIPV is a simple and rapid replacement for the more cumbersome IFA.
Comparative susceptibilities of strain MRC-5 human embryonic lung fibroblast cells and the Cooney strain of human fetal tonsil cells for isolation of rhinoviruses from clinical specimens
Authors: Geist F C , Hayden F G
Published: January 2020

The comparative susceptibilities for rhinovirus isolation were determined for strain MRC-5 human embryonic lung fibroblast and human fetal tonsil cells. Samples from nasopharyngeal and throat swab clinical specimens were inoculated onto duplicate monolayers of each cell type. Of 105 rhinovirus-positive specimens, 78 (74%) were positive in MRC-5 cells, and 102 (97%) were positive in fetal tonsil cells (P less than 0.001). For 75 specimens positive in both, the mean time to cytopathic effect development with standard deviation was 1 +/- 2 days shorter in fetal tonsil cells (P less than 0.01). The use of a second virus culture increased rhinovirus isolations by 10% compared with a single culture.
Neonatal meningitis caused by Achromobacter xylosoxidans
Authors: Namnyak S S , Holmes B , Fathalla S E
Published: January 2020

The clinical and bacteriological findings in a case of neonatal meningitis caused by Achromobacter xylosoxidans are presented. This appears to be only the second report of meningitis caused by this species.
Lectin characterization of gonococci from an outbreak caused by penicillin-resistant Neisseria gonorrhoeae
Authors: Schalla W O , Rice R J , Biddle J W , Jeanlouis Y , Larsen S A , Whittington W L
Published: January 2020

A total of 40 Neisseria gonorrhoeae isolates, representing 19 penicillin-resistant isolates (from 8 heterosexual patients and 11 homosexual patients) and 21 penicillin-susceptible isolates (from 15 heterosexual patients and 6 homosexual patients) and obtained from the same geographic area, were examined. Lectin agglutination patterns were based on the reactivity of the isolates with the following 14 lectins: concanavalin A, Lens culinaris, Trichosanthes kinlowii, Griffonia simplicifolia I, Arachis hypogeae (peanut agglutinin), Glycine max (soybean agglutinin), Dolichos bifloris, Griffonia simplicifolia II, Solanum tuberosum (potato starch agglutinin), Triticum vulgaris (wheat germ agglutinin), Limax flavus, Phaseolus vulgaris, Ulex europaeus I, and Lotus tetragonolobus. All isolates were serotyped with monoclonal antibodies specific for gonococcal outer membrane protein I and auxotyped, and the plasmid content was determined. Resistant patient isolates were selected for their decreased penicillin susceptibility, and control isolates were selected for their penicillin susceptibility. Even though the patient isolates demonstrated resistance to penicillin, no phenotypic differences in lectin-grouping patterns were demonstrated between the two study groups; i.e., two predominant lectin groups were observed. No resistance-associated plasmids were detected. All patient isolates were serogroup IB (serovars IB-1, IB-2, and IB-4), whereas 12 of 21 control isolates were serogroup IA (P less than 0.05). Isolates obtained from different anatomical sites in the same patient (cervical and rectal) agreed with regard to lectin patterns and serovars but not auxotypes.
Comparison of American MicroScan dry and frozen microdilution trays
Authors: Schieven B C , Hussain Z , Lannigan R
Published: January 2020

This study compared the American MicroScan frozen microdilution tray and dehydrated microdilution tray. A total of 153 gram-negative and 106 gram-positive isolates were tested concurrently on both tray types and read visually. Very major and major antimicrobial susceptibility discrepancies amounted to 1.0% of all results, and minor discrepancies amounted to 0.4% of all results. The biochemical discrepancy rate for gram-negative organisms was 1.3%, resulting in no identification errors either at the genus or the species level. Gram-positive identification was not evaluated, as the formulation of biochemicals was changed after this evaluation was completed. Overall, the results with the dry tray were acceptable, providing a suitable alternative to the frozen tray.
Evaluation of mannitol salt agar with oxacillin as a screening medium for methicillin-resistant Staphylococcus aureus
Authors: Lally R T , Ederer M N , Woolfrey B F
Published: January 2020

We evaluated the use of mannitol salt agar with oxacillin for use as a primary screening medium for the simultaneous detection and identification of methicillin-resistant Staphylococcus aureus in clinical surveillance specimens. Oxacillin agar dilution susceptibility tests with mannitol salt agar and Mueller-Hinton agar were performed in parallel with disk-agar diffusion testing on 95 oxacillin-susceptible and 105 oxacillin-resistant S. aureus stock isolates. MICs were found to be comparable, showing distinct separation of susceptible and resistant isolates into two groups with MICs of less than or equal to 2 and greater than or equal to 32 micrograms/ml, respectively. In accord with these findings, 4 micrograms of oxacillin per ml was selected for use in the screening medium. For performance evaluation, mannitol salt agar with 4 micrograms of oxacillin per ml was compared with mannitol salt agar without oxacillin by performing parallel screening tests on 153 clinical surveillance specimens. For detection of methicillin-resistant S. aureus, mannitol salt agar with 4 micrograms of oxacillin per ml was as sensitive as mannitol salt agar without oxacillin and required significantly fewer confirmatory tests. For primary identification of methicillin-resistant S. aureus, mannitol salt agar with 4 micrograms of oxacillin per ml was 6.4% false-positive and 1.1% false-negative, with a 93.6% positive predictive value. These findings indicate that mannitol salt agar with 4 micrograms of oxacillin per ml can be used as a reliable and cost-effective screening medium for the simultaneous detection and identification of methicillin-resistant S. aureus in clinical surveillance specimens.
Virus-specific polymeric immunoglobulin A antibodies in serum from patients with rubella, measles, varicella, and herpes zoster virus infections
Authors: Negro Ponzi A , Merlino C , Angeretti A , Penna R
Published: January 2020

More than 85% of the immunoglobulin A (IgA) antibodies in normal adult serum are monomeric (m-IgA). By contrast, virus-specific IgA is mainly polymeric (p-IgA) in sera from patients with rubella, measles, and varicella. Specific m-IgA antibodies only reach quantitative significance in late convalescence. In patients with herpes zoster, on the other hand, a varying response was observed: in three of six sera, specific IgA was absent or at a very low titer, whereas in the remaining three cases, a high titer of both p-IgA and m-IgA was noted. These results suggest that in the initial response to rubella, measles, and varicella-zoster viruses, specific IgA first appears as p-IgA and only later becomes, or is replaced by, m-IgA.
Inhibition of Campylobacter coli and Campylobacter jejuni by antibiotics used in selective growth media
Authors: Ng L K , Stiles M E , Taylor D E
Published: January 2020

The ability of Campylobacter coli and Campylobacter jejuni to grow in the presence of antibiotics used in selective growth media was compared. MIC data for C. coli indicated that some strains were more susceptible to the antibiotics than were the C. jejuni strains tested. A reduction of greater than 1 log cycle in the numbers of cells growing on plates containing antibiotics was considered to be a marked level of inhibition. Only one of nine of the antibiotic combinations studied did not markedly inhibit most of the C. coli strains tested. Although one C. coli strain was not inhibited by any of the antibiotic combinations, the other six strains were inhibited for up to 7 log cycles. The addition of blood or growth supplements reduced but did not eliminate the inhibitory effect. The inhibition of laboratory strains of C. coli on media developed for the isolation of Campylobacter spp. indicates that the incidence of C. coli may be underestimated.
Leukocyte esterase-nitrite and bioluminescence assays as urine screens
Authors: Males B M , Bartholomew W R , Amsterdam D
Published: January 2020

The 1-min leukocyte esterase (LE)-nitrite test (Chemstrip 9; Biodynamics, Division of Boehringer Mannheim Biochemicals, Indianapolis, Ind.) and a bioluminescence assay (Monolight centrifugation method; Analytical Luminescence Laboratory, Inc., San Diego, Calif.) were tested for their efficacy as urine screens among 453 patients at a tertiary-care teaching hospital. Both methods had the capacity to exclude significant bacteriuria (greater than or equal to 10(5) CFU/ml) when compared with the results of conventional culture methods, with predictive values of 99 and 93%, respectively, for a negative test. Bioluminescence was the more accurate nonculture method used. Sensitivity and specificity values were 97 and 71%, respectively, for bioluminescence, 82 and 60%, respectively, for LE with nitrite, and 72 and 64%, respectively, for LE without nitrite. At reduced levels of bacteriuria less than 10(5) CFU/ml), the sensitivities of LE-nitrite and bioluminescence were decreased but comparable. The addition of protein and blood test results in the Chemstrip 9, along with LE-nitrite as bacteriuria indicators, were unsatisfactory because of the large numbers of false-positive results attributed to protein and blood determinations. LE activity as detected by the LE test was a poor predictor of significant bacteriuria in both male and female patients. The sensitivity (71%) and specificity (57%) of the LE test in male patients were significantly lower than those previously reported and varied with the patient population studied.
Comparison of latex agglutination and counterimmunoelectrophoresis for the detection of pneumococcal antigen in elderly pneumonia patients
Authors: Cerosaletti K M , Roghmann M C , Bentley D W
Published: January 2020

A Streptococcus pneumoniae latex agglutination (LA) test (Bactigen; Wampole Laboratories, Div. Carter-Wallace, Inc., Cranbury, N.J.) and counterimmunoelectrophoresis (CIE) were compared for the detection of pneumococcal antigen in serum and urine specimens from 68 elderly patients with pneumococcal pneumonia. The cases were categorized according to the presumptive role of S. pneumoniae: definite, putative, questionable (poor score), or questionable (mixed flora). Serum and urine samples were collected on days 1 to 3, 4 to 6, and 7 to 9 of illness and screened in parallel by LA and CIE. LA detected pneumococcal antigen in the serum or urine or both from 31 (46%) of the 68 pneumococcal pneumonia cases compared with 10 (15%) of cases detected by CIE. The highest rates of detection were noted in the 17 definite (bacteremic) cases: 88% by LA and 38% by CIE. The detection rates for both tests were lower in the other nonbacteremic pneumonia categories. Pneumococcal antigen was detected more often in urine specimens than in serum specimens by LA and CIE and was detected in the urine of 92 and 46% of definite cases, respectively, after 7 to 9 days of illness despite antibiotic therapy. Both tests were specific when tested with nonpneumococcal pneumonia cases, but LA detected pneumococcal antigen in two of seven chronic bronchitis cases. This study suggests that LA is as specific and more sensitive than CIE and is useful for detecting antigen in the elderly with proven bacteremic pneumococcal pneumonia. LA is less sensitive for detecting nonbacteremic pneumococcal pneumonia and, therefore, would be of limited value in the care and study of the institutionalized elderly.
Sensitive enzyme immunoassay for detecting immunoglobulin M antibodies to Sindbis virus and further evidence that Pogosta disease is caused by a western equine encephalitis complex virus
Authors: Calisher C H , Meurman O , Brummer-Korvenkontio M , Halonen P E , Muth D J
Published: January 2020

An antibody capture enzyme immunoassay (EIA) was adapted for the detection of immunoglobulin M (IgM) antibody to Sindbis (SIN) virus. Sera from humans with a febrile illness characterized by rash and arthralgia in eastern Finland (Pogosta [POG] disease) and Sweden (Ockelbo disease) and from humans with western equine encephalitis (WEE) virus infection in the United States were tested for IgM antibodies by EIA. Seroconversions were documented in patients with POG disease and with WEE virus infections by using SIN virus as antigen and rabbit anti-SIN virus immunoglobulin; this confirms previous observations that POG disease is caused by a virus closely related to SIN virus and that IgM antibodies to WEE complex alphaviruses are not type specific. This IgM EIA provided a sensitive diagnostic and research tool applicable to epidemiologic problems posed by POG disease.
Enterotoxigenic Escherichia coli in a population of infants with diarrhea in Chile
Authors: Agüero M E , Reyes L , Prado V , Orskov I , Orskov F , Cabello F C
Published: January 2020

The incidence of enterotoxigenic Escherichia coli (ETEC) was investigated in 95 E. coli strains isolated from 48 infants with diarrhea in Santiago, Chile. By using standard biological assays and DNA-DNA hybridization procedures, ETEC was found in 31.2% of the cases: 14 strains produced heat-stable enterotoxin (ST) only, three strains produced heat-labile enterotoxin (LT) and ST, and two strains produced LT only. DNA probes detected all enterotoxin producers except one ST-producing strain. The ST strains hybridized with one or both of the human ST probes (ST Ib and ST A2). Two of the LT-ST strains hybridized with the ST Ia and ST Ib probes, and the third strain did not hybridize with any of the ST probes. Only the ST group expressed multiple resistance (85.7%) and colonization factor antigen I (CFA I) (92.8%); CFA II was found in two of three LT-ST strains. The O153:H45 serotype was found in 10 of 14 ST strains, and O6:K15:H16 was found in one LT strain and in two LT-ST strains. These findings suggest that ETEC, especially strains that produce ST, may be an important cause of diarrhea among Chilean infants.
Comparison of sedimentation and flotation techniques for identification of Cryptosporidium sp. oocysts in a large outbreak of human diarrhea
Authors: McNabb S J , Hensel D M , Welch D F , Heijbel H , McKee G L , Istre G R
Published: January 2020

Cryptosporidiosis, previously seen mostly among immunocompromised patients, is now recognized among immunocompetent patients. During a large outbreak of cryptosporidiosis in two day-care centers, we compared two procedures for the demonstration of the organism in preserved stool specimens. Of 703 stool specimens tested by both techniques, Sheather sucrose flotation (SSF) identified 127 (18.1%) as positive for Cryptosporidium sp. oocysts. Ritchie Formalin-ethyl acetate sedimentation (F/EA) plus a modified cold Kinyoun acid-fast stain (MCK) of the sediment identified 129 (18.4%) as positive for Cryptosporidium sp. oocysts. The degree of agreement between the two tests was statistically highly significant (P less than 0.0001). A total of 161 (22.9%) were positive by one technique or the other; 95 (13.5%) were positive by both techniques. A total of 32 specimens were positive by SSF but negative by F/EA plus MCK, and 34 specimens were positive by F/EA plus MCK but negative by SSF. The discrepancies between the two techniques occurred in stool specimens that contained rare to a few oocysts. Other parasitic forms were found by both techniques. F/EA plus trichrome staining recovered 126 (17.9%) specimens with Giardia lamblia, whereas SSF recovered only 42 (6.0%) specimens with G. lamblia. No association (chi 2 = 0.02, P = 0.89) was observed between the presence of G. lamblia and Cryptosporidium sp. in these stool specimens. We concluded that F/EA plus MCK of the sediment was as effective in the concentration and identification of Cryptosporidium sp. oocysts as SSF. F/EA plus MCK may be advantageous as a single concentration method for general parasitology when Cryptosporidium sp. is also being sought.
H7 antiserum-sorbitol fermentation medium: a single tube screening medium for detecting Escherichia coli O157:H7 associated with hemorrhagic colitis
Authors: Farmer J J , Davis B R
Published: January 2020

Escherichia coli serotype O157:H7 has been isolated from outbreaks and sporadic cases of hemorrhagic colitis. There is convincing evidence that it can cause this diarrheal disease. Because of the interest in hemorrhagic colitis, it has become desirable to detect this particular strain in human feces, which usually contains many other strains of E. coli. Two characteristics of the incriminated E. coli O157:H7 strain have made its isolation and identification easier. It does not ferment D-sorbitol rapidly, in contrast to about 95% of other E. coli strains. In addition, the strain has H antigen 7, but only about 10% of other E. coli strains have this particular antigen. To screen for E. coli O157:H7 we devised H7 antiserum-sorbitol fermentation medium (18 g of enteric fermentation base, 10 g of D-sorbitol, 4 g of agar, 10 ml of Andrade indicator, 989 ml of water; all ingredients were mixed, autoclaved, and cooled; 1 ml of E. coli H7 antiserum was then added). Colonies to be screened were inoculated into this medium. Strains of E. coli O157:H7 gave a characteristic pattern; they did not ferment sorbitol and were immobilized in the semisolid medium because of the reaction of their flagella with the flagella antiserum. Almost all other strains of E. coli gave a different pattern; they fermented sorbitol or were not immobilized by the H7 serum or both. Strains which were presumptive positives (sorbitol negative, H7 positive) were then tested in E. coli O157 serum by slide or tube agglutination. The number of strains which were presumptive positive by H7-sorbitol medium but then were not found to be O157 was less than 1%. A second approach has been helpful in deciding which colonies to screen in H7-sorbitol medium. MacConkey-sorbitol agar (22.2 g MacConkey agar base [which contains no sugar], 10 g of D-sorbitol, 1,000 ml of water) was designed as a plating medium. Stools were plated on MacConkey agar to estimate the number of E. coli colonies and also plated on MacConkey-sorbitol agar to estimate the number of sorbitol-negative colonies of E. coli. These two approaches have proved useful for isolating and identifying E. coli O157:H7 form human feces and from feces of animals infected in the laboratory with this strain. The results suggest that media may be formulated in a similar fashion for detecting other specific strains of E. coli.
Detection of herpes simplex virus type 2-specific antibody with glycoprotein G
Authors: Lee F K , Coleman R M , Pereira L , Bailey P D , Tatsuno M , Nahmias A J
Published: January 2020

A recently described herpes simplex virus (HSV) type 2 (HSV-2)-specific glycoprotein (gG-2) was purified on an immunoaffinity column prepared with monoclonal antibody. This purified antigen was used in an immunodot enzymatic assay on nitrocellulose paper for the detection of HSV-2 antibodies in human serum. The test was very sensitive in that HSV-2 antibodies were detected in the convalescent sera of 132 of 134 patients with recurrent genital infections in which HSV-2 had been isolated earlier. Antibodies to gG-2 were detected in 17% of sera obtained within 10 days after the onset of a primary HSV infection and in 95% of sera obtained more than 10 days after onset. The specificity of the immunodot assay was demonstrated by testing sera from 245 HSV-seronegative adults, 344 children, 29 nuns, and 13 patients with primary genital HSV-1 infections. None of these 631 sera was reactive with the gG-2 antigen. When compared with a microneutralization test, the immunodot assay was found to be more specific in detecting HSV-2 antibodies. Reproducibility of the gG-2 assay, obtained by retesting 391 sera, was 95%. Thus, this assay has the sensitivity, specificity, and reproducibility necessary for the measurement of HSV-2 antibodies in seroepidemiological studies.
Cryopreserved erythrocytes in clinical laboratory hemagglutination and hemagglutination inhibition tests
Authors: Maes R K , Hayes M M , Newman J P
Published: January 2020

Various concentrations of pig, guinea pig, chicken, and turkey erythrocytes (RBCs) were cryopreserved and compared with fresh RBCs in hemagglutination and hemagglutination inhibition tests. Hemagglutination and hemagglutination inhibition titers obtained with cryopreserved or fresh RBCs from the same donor differed by not more than one twofold dilution. RBCs cryopreserved at a concentration of less than or equal to 12.5% gave the highest percent recovery upon thawing.
Examination of preserved stool specimens for parasites: lack of value of the direct wet mount
Authors: Estevez E G , Levine J A
Published: January 2020

To review the appropriateness of standard reference procedures for diagnostic parasitology, we examined 2,206 stool specimens in our laboratory by direct wet mounting with saline and iodine, by saline and iodine wet mounting from Formalin-ethyl acetate concentrates, and by permanent staining with Wheatley's modified trichrome method (W.B. Wheatley, Am. J. Clin. Pathol. 21: 990-991, 1951). Parasites were detected in 98 stool specimens (4.4%). In all but three specimens, direct wet mounting with saline and iodine contributed little significant information to the result yet consumed substantial technical time. We recommend that with preserved feces a direct examination not be performed but that examination of both a concentrate and a permanent stain be routine.
Serotypes of bovine astrovirus
Authors: Woode G N , Gourley N E , Pohlenz J F , Liebler E M , Mathews S L , Hutchinson M P
Published: January 2020

Three isolates of bovine astrovirus, one from the United Kingdom and two from the United States, possessed common antigens by immunofluorescence and strain-specific antigens by neutralization and were designated as two, and probably three, distinct serotypes. The isolate US2, despite being a different serotype, possessed the same restrictive cell tropism and cytopathology as previously reported for isolate US1, of the M cells of the dome epithelium of the Peyer's patches. Serotyping of 16 field isolates indicated the presence of more undefined serotypes.
Isolation of the Mycobacterium leprae-specific glycolipid antigen, phenolic glycolipid-I, from formalin-fixed human lepromatous liver
Authors: Izumi S , Sugiyama K , Fujiwara T , Hunter S W , Brennan P J
Published: January 2020

A Mycobacterium leprae-specific phenolic glycolipid antigen was purified from Formalin-fixed liver preserved from an advanced lepromatous leprosy patient. Its chemical and immunological properties were compared with those of phenolic glycolipid-I obtained from M. leprae-infected armadillo liver. Based on the findings that the glycolipids from the two sources have the same thin-layer chromatographic properties, infrared absorption spectrum, sugar composition, and seroreactivity, we conclude that large quantities of the phenolic glycolipid-I antigen are produced in human lepromatous leprosy lesions and that Formalin-fixed lepromatous livers and spleens from the prechemotherapeutic era are suitable sources of the glycolipid.
Septicemia caused by Agrobacterium sp
Authors: Freney J , Gruer L D , Bornstein N , Kiredjian M , Guilvout I , Letouzey M N , Combe C , Fleurette J
Published: January 2020

Agrobacterium radiobacter biovar 2 was repeatedly grown from the blood of an elderly patient receiving artificial ventilation and broad-spectrum antibiotics. No source of the organism was found, but the septicemia ceased when cefotaxime was given. Sera from the patient showed a fourfold rise in antibody against the organism and higher titers than sera from all but 1 of 50 healthy blood donors. The organism did not contain the plasmid associated with plant oncogenicity. This case may be only the second in which Agrobacterium sp. has been clearly linked with human infection.
Comparative efficiency of commercial immunoassays for the diagnosis of rotavirus gastroenteritis during the course of infection
Authors: Miotti P G , Eiden J , Yolken R H
Published: January 2020

We evaluated the performance characteristics of three commercially available immunoassays for the detection of rotavirus antigens in stool samples obtained from infants during the course of rotavirus gastroenteritis. Two of the assays, Bio-EnzaBead (Litton Bionetics, Charleston, S.C.) and Rotazyme (Abbott Laboratories, North Chicago, Ill.), are enzyme immunoassays, while the third, Rotalex (Medical Technology Corporation, Somerset, N.J.), is a latex agglutination assay. We tested a total of 122 samples obtained from 26 children with gastroenteritis; 56 samples, obtained from 21 children, were found to contain rotavirus antigen by a reference microplate enzyme immunoassay. Rotavirus antigen was found by the Bio-EnzaBead, Rotazyme, and Rotalex assays in 53, 42, and 29 samples, respectively. The true positivity of samples which were positive by the reference microplate assay but negative by the other assays was confirmed by a specific neutralization assay or by the visualization of bands of double-stranded RNA by polyacrylamide gel electrophoresis or both. No false-positive assay results were noted with any of the commercial assays. The sensitivity of the assays was determined to a great extent by the time after the onset of illness at which the specimen was collected. Thus, the sensitivity of commercial assays with specimens collected early in the course of illness did not differ significantly from that of the microplate assay. However, significantly lower degrees of sensitivity were noted later in the course of illness. Results of our studies indicate that all three commercial assays can accurately detect rotavirus in stools from children with rotavirus gastroenteritis. However, the choice of assay systems for use in the clinical laboratory will depend on the conditions in which stool specimens are collected and tested in the laboratory.
Measurement of amikacin in serum by a latex agglutination inhibition test
Authors: Khabbaz R F , Standiford H C , Bernstein D , Nipper H C , Tatem B A , Smalls U , Drusano G L , Caplan E
Published: January 2020

Levels of amikacin in serum were determined in 106 serum specimens by a latex agglutination inhibition card test and by radioimmunoassay (RIA). Linear regression analysis demonstrated a high degree of correlation between the two assays (latex = 0.95 (RIA) + 0.69; r = 0.97). Assay of three control sera containing 7.5, 15, and 30 micrograms of amikacin per ml on 7 separate days showed good reproducibility with a coefficient of variation of 0 to 11.7% for the latex assay compared with 7.01 to 22.2% for RIA. Recovery of amikacin in spiked sera varied between 93 and 108% for the latex assay compared with 90 and 100% for RIA. Because the procedure involves a titer, the latex agglutination inhibition card test produces results which are categorized rather than results which are continuous. However, it is a rapid and specific method for determining amikacin levels in clinical specimens and is particularly useful when processing small numbers of specimens.
Comparison of four hippurate hydrolysis methods for identification of thermophilic Campylobacter spp
Authors: Morris G K , el Sherbeeny M R , Patton C M , Kodaka H , Lombard G L , Edmonds P , Hollis D G , Brenner D J
Published: January 2020

The test for hippurate hydrolysis is critical for separation of Campylobacter jejuni and C. coli strains. Glycine and benzoic acid are formed when hippurate is hydrolyzed by C. jejuni. The test used in most laboratories is one of several variations of the ninhydrin tube test described by Hwang and Ederer (M. Hwang and G. M. Ederer, J. Clin. Microbiol. 1:114-115, 1975) for detection of glycine. We evaluated three modifications of the Hwang and Ederer method and the gas-liquid chromatographic (GLC) method described by Kodaka et al. (H. Kodaka, G. L. Lombard, and V. R. Dowell, Jr., J. Clin. Microbiol. 16:962-964, 1982) for detecting benzoic acid. Campylobacter strains comprised 22 C. jejuni, 11 C. coli, and 8 C. laridis strains. The species identification of each strain was confirmed by DNA relatedness. All strains of C. jejuni were positive and all strains of C. coli and C. laridis were negative by the GLC method for detecting hippurate hydrolysis, whereas three strains of C. jejuni gave negative or variable results in the tube tests. The GLC method is more sensitive than the tube methods for detecting hippurate hydrolysis and should be used on cultures yielding variable or questionable test results.
Clinical laboratory studies of disinfection with Sporicidin
Authors: Isenberg H D
Published: January 2020

The clinical microbiology laboratory evaluation of disinfectants can serve as a guide for their application to reduce hospital-acquired infections. The use of Sporicidin, a glutaraldehyde-phenol formulation, was evaluated by the application of modified MIC and MBC determinations for standard organisms. In addition, the effect of this formulation on bacteria that may proliferate in water at ambient temperatures was studied. This investigation indicated that such studies can help the clinical microbiologist to guide the use of disinfectants and sterilants for the maintenance of a safe hospital environment.
Rapid diagnosis of LaCrosse encephalitis: detection of specific immunoglobulin M in cerebrospinal fluid
Authors: Dykers T I , Brown K L , Gundersen C B , Beaty B J
Published: January 2020

An immunoglobulin M (IgM) antibody capture enzyme immunoassay (MAC-EIA) was developed for the rapid and early diagnosis of LaCrosse (LAC) virus infections. The MAC-EIA was a sensitive and specific technique for the detection of IgM antibodies to LAC virus in cerebrospinal fluid specimens and in acute-phase serum specimens. In a retrospective study, cerebrospinal fluid and acute-phase serum paired samples from 108 patients were tested by the MAC-EIA and by an IgM immunofluorescence assay. The results were compared with the original diagnosis, which was made by using a variety of classical serological tests including serum neutralization, hemagglutination inhibition, and complement fixation. Thirty patients were confirmed as having LAC virus infections; of these, 30 (100%) were diagnosed as positive by serum MAC-EIA, and 27 (90%) were positive by cerebrospinal fluid MAC-EIA. The MAC-EIA was more sensitive than the IgM immunofluorescence assay. Two patients who were not previously confirmed as positive cases were diagnosed as having LAC virus infections by the MAC-EIA. One patient who was subsequently diagnosed as having a Jamestown Canyon virus infection and two patients who were previously infected with Jamestown Canyon virus were not falsely identified as having LAC virus infections by the MAC-EIA.
Clinically significant cross-reactions with counterimmunoelectrophoresis between pneumococcus type 6 and Haemophilus influenzae type b
Authors: Ballard T L , Spangler A , Roe M H , Glode M P
Published: January 2020

Biologically and clinically significant cross-reactions may occur between the immunochemically similar capsule antigens of Haemophilus influenzae type b and Streptococcus pneumoniae type 6 by using counterimmunoelectrophoresis (CIE). In three cases of culture-proven S. pneumoniae type 6 disease, a false-positive H. influenzae type b CIE result was detected in a body fluid. Two of three cases were also positive when tested by CIE with pneumococcal omnisera. However, in one of the culture-proven cases of pneumococcal type 6 disease, the omniserum was negative and only the burro 132 H. influenzae type b antiserum demonstrated a positive precipitant reaction. In addition to the three case isolates, we evaluated nine blood or cerebrospinal fluid isolates of pneumococcus type 6, using a variety of both species- and type-specific antisera, by CIE. Two burro antisera detected 12 of 12 (100%) of the S. pneumoniae type 6 strains. A rabbit H. influenzae type b antiserum did not detect any (0 of 12; 0%) of the S. pneumoniae type 6 strains evaluated. All (12 of 12; 100%) of the S. pneumoniae type 6 strains were detected with both rabbit omniserum (S. pneumoniae) and rabbit type 6 antiserum. Our data illustrate the importance of being aware of the immunologic cross-reactivity of the H. influenzae type b capsule with the pneumococcus type 6 capsule and the possibility of false-positive results with CIE when patient specimens are interpreted.
Rapid viral diagnosis of acute respiratory infections: comparison of enzyme-linked immunosorbent assay and the immunofluorescence technique for detection of viral antigens in nasopharyngeal secretions
Authors: Grandien M , Pettersson C A , Gardner P S , Linde A , Stanton A
Published: January 2020

Nasopharyngeal secretions from adults and children were obtained in Stockholm, Sweden, for routine diagnosis of influenza A virus, influenza B virus, respiratory syncytial (RS) virus, parainfluenza type 3 virus, and adenovirus infections by demonstration of viral antigens directly in the specimens. The cells in nasopharyngeal secretions were pelleted by centrifugation for preparation of cell deposits for diagnosis by the immunofluorescence technique (IF) in London, England, and in Stockholm, whereas the supernatants were used to diagnose infection by the enzyme-linked immunosorbent assay (ELISA) in Stockholm. Titrations of the various purified viruses showed that ELISA could detect viral antigens in amounts corresponding to 1 to 10 ng of virus protein per test well. In a series of 73 specimens tested for influenza A, RS, and parainfluenza type 3 viruses by IF in London and by ELISA in Stockholm, 15 of 18 RS, 14 of 15 influenza A, and 2 of 2 parainfluenza type 3 viral infections were diagnosed by ELISA as compared with IF, giving sensitivities for RS and influenza A viral diagnosis of 83 and 93%, respectively, and a specificity of 100%. In another series of specimens from 35 patients tested for influenza B virus and adenovirus, five influenza B virus and four adenovirus infections were diagnosed by both methods; one additional influenza B infection was detected only by IF and another only by ELISA. Comparisons of diagnostic results between the two methods performed in Stockholm gave nonagreement of results for 37 of 1,593 tests (2.5%) for the five viruses. The conclusion reached was that the described ELISA, although a satisfactory test, had somewhat less sensitivity than did IF for the detection of respiratory viral infections. This could possibly be explained by unnecessary dilutions of specimens at the time of collection; transportation, processing, and storage of specimens were less complicated than for IF.