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Biomedical subjects

W H Traub

Publications and source records attributed to W H Traub.

At least 19 recordsLinked to original sources

Examination of polyclonal rabbit immune sera against serovars of Acinetobacter baumannii and genospecies 3 for cross-reactions with reference strains of other named/unnamed genospecies of Acinetobacter.

Polyclonal rabbit immune sera against 38 serovars of Acinetobacter baumannii and genospecies 13 capable of growth at 44 degrees C and against 26 serovars of genospecies 3 and genospecies 13 incapable of growth at 44 degrees C were examined for serological cross-reactivity with reference strains comprising 17 genospecies (among them 6 named species) of Acinetobacter. Checkerboard agglutination tests yielded very few cross-reactions. Specifically, genospecies 17 cross-reacted weakly with A. baumannii serovar 27; strains genospecies 13 (Bouvet), TU 14, and 'close to TU 13' were strongly agglutinated by antiserum against A. baumannii serovar 18. Genospecies 14 (Bouvet) yielded a very weak cross-reaction with genospecies 3 serovar 20, and genospecies TU 13 reacted weakly with anti-genospecies 3 serovar 15 serum. The 'between genospecies 1 and 3' reference strain proved to be A. baumannii serovar 5 as determined with absorption tests.

Acinetobacter↗

Serotyping of clinical isolates of Acinetobacter baumannii and genospecies 13 capable of growth at 44 degrees C: detection of four new serovars.

Four new serovars (sv 35-38) were detected among clinical isolates of Acinetobacter baumannii and the unnamed genospecies 13 capable of growth at 44 degrees C. Polyclonal rabbit antisera were serovar-specific. None of them cross-reacted with 34 previously recognized servars of A. baumannii and genospecies 13 nor with 26 serovars of genospecies 3.

Acinetobacter↗

Structures of polymeric products isolated from the lipopolysaccharides of reference strains for Acinetobacter baumannii O23 and O12.

A polysaccharide containing D-galactose (Gal), 2-acetamido-2-deoxy-D-galactose (GalNAc), 2-acetamido-2-deoxy-D-glucose (GlcNAc), and 3-deoxy-3-(D-3-hydroxybutyramido)-D-quinovose (Qui3NR) was isolated from lipopolysaccharide (LPS) obtained from cells walls of the reference strain for Acinetobacter baumannii O23. By means of NMR studies, methylation analysis, and chemical degradations, the repeating unit of the polymer was identified as a branched pentasaccharide with the structure 1. The same polymer was apparently also present in LPS of the reference strain for serogroup O12, together with a second polymer based on a branched tetrasaccharide with the structure 2. This second polymer has previously been isolated as the O16 antigen of A. baumannii [Haseley, S.R., Diggle, H.J. & Wilkinson, S. G. (1996) Carbohydr. Res. 293, 259-265] and is probably present as a minor component of the LPS of A. baumannii O11 [Haseley, S.R. & Wilkinson, S.G. (1996) Eur. J. Biochem. 237, 266-271]. [Sequence: see text]

Acinetobacter↗

Macrorestriction analysis (PFGE) of serologically cross-reactive serovars of Acinetobacter baumannii and genospecies 3.

Forty-two serovar reference strains of Acinetobacter baumannii and genospecies 3, which yielded major or minor, one-way or two-way (reciprocal) serological cross-reactions, were subjected to macrorestriction (SmaI, ApaI) analysis with the aid of pulsed-field gel electrophoresis (PFGE). The PFGE patterns of serovars 3 and 21 of genospecies 3 differed by 3 (SmaI) and 2-4 (ApaI) DNA fragments and thus were closely/possibly related in their genotype. Serovars 13 and 26 of genospecies 3 differed by only 2 DNA fragments (SmaI), suggesting close genetic relatedness; however, these two particular serovars of genospecies 3 appeared to be genotypically indistinguishable following restriction with ApaI. Serovars 2, 4, and 12 of genospecies 3 appeared to be unrelated to serovar 13 of genospecies 3 (SmaI); however, restriction with ApaI indicated a possible relatedness. Genospecies 3 serovars 2 and 26 differed by 5 DNA fragments (SmaI and ApaI), implying a possible relatedness. All other cross-reactive serovars examined proved to be genotypically unrelated, i.e., differed by > or = 7 DNA fragments (SmaI restriction).

Acinetobacter↗

Phenotypic and genotypic characterization of clinically recovered presumptive Acinetobacter baumannii isolates which failed to grow at 44 degrees C.

Eleven clinical isolates of Acinetobacter, which exhibited an identical biochemical profile compatible with genospecies 3 and failed to grow at 44 degrees C, were not agglutinated by polyclonal rabbit immune sera against 26 serovars of genospecies 3. Rather, all 11 isolates reacted strongly with antiserum against serovar 18 of A. baumannii. Macrorestriction (SmaI) analysis of genomic DNA revealed that only one isolate was genotypically different, whereas the remaining ones were either closely related or identical. However, the genomic DNA of the A. baumannii serovar 18 reference strain proved to be genotypically unrelated.

Acinetobacter↗

Typing of nosocomial strains of Serratia marcescens: comparison of restriction enzyme cleaved genomic DNA fragment (PFGE) analysis with bacteriocin typing, biochemical profiles and serotyping.

Eighty-eight selected clinical isolates of Serratia marcescens, representing 27 putative outbreaks of nosocomial cross-infection encountered during 1980-1995, were tested comparatively by bacteriocin typing, carbon source assimilation tests, serotyping (O and H antigens), and restriction pattern (RFLP) analysis of restriction cleaved (SpeI, XbaI) genomic DNA fragments after pulsed-field gel electrophoresis (PFGE). Serotyping served as the "gold standard" of the phenotypic methods. One pseudo-outbreak (bacteriocin typing incriminated type 26) was uncovered through serotyping as well as the biochemical profile and confirmed by PFGE analysis of genomic DNA. Bacteriocin typing and determination of biochemical profiles disclosed several instances of phenotypic variation; serotyping revealed two episodes of shifts from motility (H12) to nonmotility. Resolution of restricted genomic DNA fragments with the PFGE procedure permitted detection of 27 PFGE patterns (A-M, N-1-N-3, O-1, O-2, P-1-P-3, Q-1-Q-3, R-1-R-3, S-1, and T). Based on the analysis of PFGE patterns against the background of epidemiological data, the number of nosocomically significant strains of S. marcescens could be reduced to 16 (PFGE patterns A-M, N-2, O-1, P-2, and T). It was concluded that PFGE analysis of restricted genomic DNA of S. marcescens was superior to the three phenotypic methods.

Animals↗

Clusters of nosocomial cross-infection due to Acinetobacter baumannii and genospecies 3: comparison of serotyping with macrorestriction analysis of genomic DNA with pulsed-field gel electrophoresis.

Triplets of isolates representing 20 putative clusters of nosocomial cross-infection due to Acinetobacter baumannii and genospecies 3 were examined comparatively using serotyping and analysis of restriction fragments (SmaI and ApaI) of genomic DNA with the aid of pulsed-field gel electrophoresis. Carbon source assimilation tests disclosed phenotypic variation among 6 to 20 triplets of isolates. Two misleading results of serotyping were encountered. With respect to the presumptive cluster No. 9, one of the genospecies 3 (originally serovar 4) isolates proved to be polyagglutinable upon repeat examination; this particular putative cluster was shown to be a pseudocluster by comparison of the macrorestriction profiles of the respective triple isolates. A strain of A. baumannii serovar 15 had infected 8 patients in a surgical intensive care unit, while a second, genotypically totally different strain of identical serovar had caused infection in one additional patient. With this exception, the correlation between serotyping and analysis of macrorestriction profiles was excellent.

Acinetobacter↗

Phenotypic variation of clinical Serratia marcescens isolates repeatedly recovered from individual patients.

A total of 129 selected isolates of Serratia marcescens which had been recovered from 50 patients during the 1980-1995 period and which revealed phenotypic variation in terms of bacteriocin (phage tail) susceptibility, carbon source assimilation, or serotype, were reexamined with these three phenotypic methods. Seven isolates (5.4%) were bacteriocin nontypable; all 129 isolates utilized carbon sources and could be serotyped. Fourty-eight isolates from 20 patients yielded unambiguous results with these 3 phenotypic methods and were excluded from further analysis. Among the remaining 81 isolates from 30 patients, isolates from 2 patients revealed phenotypic variation in bacteriocin susceptibility only, whereas isolates from 6 patients showed variant bacteriocin types and variant biochemical profiles, but were of identical serotype. Isolates from 20 patients revealed variant biochemical profiles only. Three patients had become superinfected with strains of S. marcescens of different phenotype and genotype. In 4 patients, previously motile (H12) isolates had become nonmotile (H-). PFGE analysis of XbaI and SpeI-restricted genomic DNA of the 81 isolates of the 30 patients demonstrated the isolates of 22 patients to be genotypically identical. The isolates from 3 patients were closely related by genotype, and those from an additional patient proved to be possibly related. PFGE analysis demonstrated one patient to have become infected by two genotypically different strains of S. marcescens of identical serotype, which, however, differed in bacteriocin type and biochemical profile. It was concluded that PFGE analysis of restricted genomic S. marcescens DNA was superior to the three phenotypic methods examined comparatively. Serotyping was more reliable than bacteriocin typing, and the latter technique yielded fewer phenotypic variants than determination of biochemical profiles among consecutively recovered isolates from patients with long-lasting S. marcescens infection.

Bacterial Typing Techniques↗

Simplified purification of Listeria monocytogenes listeriolysin O and preliminary application in the enzyme-linked immunosorbent assay (ELISA).

A simplified procedure was developed for purification of listeriolysin O (LLO) of Listeria monocytogenes, consisting of hydroxylapatite adsorption chromatography followed by Sepharose S ion exchange chromatography. The LLO (58 kDa) appeared pure in terms of sodium dodecylsulfate polyacrylamide electrophoresis and immunoblots with polyclonal rabbit immune sera. The purified LLO could be stored at -65 degrees C for 1 year without loss of immunoreactivity. Similarly, flat-bottom microtiter strips from two vendors that had been charged with LLO, could be stored at -65 degrees C for up to 3 months without loss of LLO. Three patients with documented listeriosis developed elevated IgG titres against LLO; 2 of the patients revealed minimally raised IgM titres, as determined with the enzyme-linked immunosorbent assay.

Animals↗

Heat stability of the antimicrobial activity of sixty-two antibacterial agents.

Sixty-two antimicrobial agents, including several combinations, were examined for stability at 56 degrees C for 30 min and 121 degrees C for 15 min, respectively. A microtiter broth dilution MIC test and an agar disk diffusion test served to test each chemo-agent for residual antimicrobial activity. Eleven drugs were partially heat-labile (MICs raised four- to eight-fold after autoclaving) and 26 drugs were heat-labile (MICs raised > or = 16-fold following autoclaving); the remainder proved heat-stable (MICs raised < or = two-fold after autoclaving). Surprisingly, the beta-lactams, azlocillin, aztreonam, mezlocillin, and oxacillin, were remarkably heat-stable.

Anti-Bacterial Agents↗

Agar disk diffusion (Bauer-Kirby) tests with various fastidious and nonfastidious reference (ATCC) strains: comparison of several agar media.

Several agar media (Mueller-Hinton agar, MHA; diagnostic sensitivity test agar, DSTA; Schaedler agar, SchA; Todd-Hewitt agar with added yeast extract, THYA; Wilkins-Chalgren agar, WCA) were compared using the Bauer-Kirby agar disk diffusion test against six nonfastidious quality control strains: Staphylococcus aureus ATCC 25923 and ATCC 29213, Escherichia coli ATCC 25922 and ATCC 35218, Pseudomonas aeruginosa ATCC 27853, and Enterococcus faecalis ATCC 29212. MHA, DSTA, and THYA yielded essentially comparable inhibition zones. However, WCA and SchA antagonized cotrimoxazole and aminoglycoside antibiotics; furthermore, SchA antagonized polymyxin B, and both WCA and SchA antagonized imipenem against the P. aeruginosa strain, but not against the E. coli strains. Sheep blood-MHA (Bl-MHA), WCA, THYA, and DSTA were examined with Streptococcus pyogenes ATCC 19615, Streptococcus agalactiae ATCC 13813, and Streptococcus pneumoniae ATCC 6306. In comparison with Bl-MHA, both WCA and THYA yielded comparable inhibition zones against S. pyogenes; DSTA afforded suboptimal growth. DSTA yielded larger inhibition zones with the majority of antimicrobial drugs against S. agalactiae, whereas WCA and THYA enhanced the activity of oxacillin and penicillin G against this strain. S. pneumoniae strain ATCC 6306 grew well on Bl-MHA, yielded suboptimal growth on WCA and faint growth on THYA, and failed to grow on DSTA. Chocolate-supplemented sheep blood-MHA (CHOC-MHA) was compared with Haemophilus test medium (HTM), WCA with added NAD, and THYA with added hematin and NAD against Haemophilus influenzae strains ATCC 35056 and ATCC 49247. The activities of doxycycline and rifampin were enhanced against both strains by HTM, WCA+NAD, and THYA+hematin+NAD. Only WCA+NAD antagonized cotrimoxazole against both H. influenzae strains, an effect due to thymidine; however, HTM antagonized cotrimoxazole against S. aureus ATCC 25923 and E. coli ATCC 25922. It was concluded that Bl-MHA performed best for beta-hemolytic streptococci quality control strains. Likewise, CHOC-MHA was optimal for the two H. influenzae strains used in this comparative agar disk diffusion study.

Agar↗

Immunobiology of Acinetobacter baumannii and genospecies 3.

Five representative, taxonomically and serologically defined clinical isolates of Acinetobacter baumannii and genospecies 3, and A. baumannii strain ATCC 19606 were examined for immunogenicity in rabbits following experimental bacteremia. All rabbits seroconverted as determined with the aid of the tube O-agglutination, indirect hemagglutination, and enzyme-linked immunosorbent assay (ELISA) procedures. Immunoblots detected over twenty immunogenic, proteinase-K-degradable polypeptide antigens in trichloroacetic acid extracts, outer membrane protein fractions, and mechanically disrupted (type MM2 mixer drill) cell preparations. Sodium periodate-susceptible phenol-water and phenol-chloroform-light petroleum lipopolysaccharide (LPS) extracts proved to be immunogenic for the rabbits as well. Convalescent sera from two patients with documented bacteremia due to genospecies 3, serovar 4, likewise revealed numerous anti-polypeptide and anti-LPS antibodies comprising the immunoglobulin G (IgG) and the IgM class.

Acinetobacter↗

A 41.7 kDa serine protease from Clostridium perfringens type A: degradation of purified human serum proteins.

Two clinical isolates of Clostridium perfringens type A produced a novel caseinolytic serine protease. Both enzymes had a molecular weight of 41.7 kilodaltons and an isoelectric point of 9.1. The two enzymes were immunogenic for rabbits and closely related serologically. Both enzymes partially degraded the heavy chains of human immunoglobulins (Ig) G and IgM, but not IgA. Purified human complement (C) components C3, C5, C8, and C9 were attacked; C1q was refractory. Both enzymes were active against human transferrin, alpha 1-antitrypsin, alpha 2-macroglobulin, haptoglobin, type III fibrinogen, and fibronectin. C-reactive protein was refractory.

Blood Proteins↗

Detection of antimicrobial drugs with Bacillus subtilis strain ATCC 6633: an update.

Bacillus subtilis strain ATCC 6633 was examined for susceptibility to 30 additional antimicrobial drugs, the majority of which had been released during the 1980s. The data served to update previous findings with regard to the suitability of this assay strain for the detection of chemotherapeutic agents in fluid clinical specimens.

Anti-Bacterial Agents↗

Comparative biotyping, bacteriocin typing, and serogrouping (O-antigens) of Serratia liquefaciens.

A total of 83 clinical isolates of Serratia liquefaciens from 81 patients were biotyped, bacteriocin typed (with group A phage tail bacteriocins from S. marcescens), and serogrouped. Biotyping afforded least discrimination, because 71 of the 83 isolates (85.5%) comprised 2 biotypes; the remainder were of 5 different biotypes. Bacteriocin typing differentiated 70 of the 83 isolates (84.3%) into 20 types. Polyclonal rabbit anti-O immune sera identified 16 O-antigens, and all 83 isolates could be serogrouped.

Antigens, Bacterial↗

Serotyping of Serratia liquefaciens: H-antigens.

Polyclonal anti-H rabbit immune sera differentiated 12 flagellar (H) antigens among 79 motile of 83 clinical isolates of Serratia liquefaciens from 81 patients. Seven of the anti-H S. liquefaciens sera cross-reacted with H-antigens of S. marcescens, specifically anti-S. liquefaciens H6, H7, H8, H9, H10, H11, and H12 with S. marcescens H-antigens H7, H8, H12, H14, H5, H3, and H17, respectively. These cross-reactions were reciprocal.

Antigens, Bacterial↗

Bacteriocin typing and biotyping of clinical isolates of Serratia marcescens.

A total of 727 clinical isolates of Serratia marcescens from 474 patients were typed for bacteriocin susceptibility; 707 of the isolates (97.25%) were typable and comprised 46 different bacteriocin types. The biotyping method of Grimont and Grimont permitted categorization of 726 of the 727 isolates into 50 biotype profiles. However, 98 of the 726 biotypable isolates (13.5%) yielded previously unknown biotype profiles; similarly, 24 out of 59 reference strains of S. marcescens gave biotype profiles that had not been encountered before. Multiple S. marcescens isolates (366 of the 727 isolates) had been recovered from 113 patients. Phenotypic variation in bacteriocin susceptibility occurred in 15 of these patients, whereas phenotypic variation in biotype profiles was noted in 26 of these patients. In 5 of the 113 patients, phenotypic variation accounted for changes both in bacteriocin type and in biotype profile. It is suggested that serotyping should remain the method of choice until new methods have been evaluated accordingly.

Bacterial Typing Techniques↗