The magnitude of bacteremia in infants with group B streptococcal disease.
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Child↗
Biomedical subjects
F S Nolte
Publications and source records attributed to F S Nolte.
Primary pulmonary infection caused by Mycobacterium terrae complex.
The Mycobacterium terrae complex, consisting of three saprophytic species, M. terrae, M. nonchromogenicum, and M. triviale, rarely causes human disease. Only six cases of respiratory infection involving the complex have been documented worldwide. A case of primary pulmonary disease in a previously healthy young woman caused by M. terrae complex is described.
Adult↗
Proctitis and fatal septicemia caused by Plesiomonas shigelloides in a bisexual man.
A case of proctitis and fatal septicemia caused by Plesiomonas shigelloides in a 42-year-old bisexual male is reported. The medical history of the patient was significant for an aortic valve replacement 3 years before but was otherwise unremarkable. A serum specimen obtained at autopsy was negative for antibody to human immunodeficiency virus by Western blot (immunoblot) analysis. P. shigelloides isolated from blood was susceptible to all antibiotics tested, agglutinated in Shigella group D antiserum, possessed a greater than 100-megadalton plasmid, and was noninvasive in a HeLa cell invasion assay. The previous reports of Plesiomonas bacteremic infections are reviewed, and possible pathogenic mechanisms are discussed.
Adult↗
Rapid and overnight microdilution antibiotic susceptibility testing with the Sensititre Breakpoint Autoreader system.
The Sensititre Breakpoint Autoreader system (SBAS) is a broth microdilution method with one to three concentrations of each antibiotic and innovative fluorescence technology to define inhibitory endpoints. We tested 248 gram-negative bacilli and 80 gram-positive cocci using both the rapid (5 h) and overnight (18 h) SBAS procedures. Inhibitory endpoints were also determined by visual inspection of the microdilution trays after 18 h of incubation. SBAS results were compared with those obtained by a standardized disk diffusion (SDD) procedure. Agreement between the rapid SBAS and SDD results for all antibiotic-organism combinations was found in 3,730 of 4,571 (81.6%) tests, with 3.9% very major, 6.5% major, and 7.9% minor discrepancies noted. Data analysis by organism group revealed 86.8, 57.3, 71.4, and 62.3% agreement for members of the family Enterobacteriaceae, Pseudomonas spp., staphylococci, and enterococci, respectively. The results of the overnight SBAS and SDD agreed in 4,154 of 4,654 (89.2%) tests, with 2.3% very major, 1.3% major, and 7.1% minor discrepancies recorded. Concordance was noted in 90.4, 78.1, 90.6, and 83.3% of the comparisons for the members of the Enterobacteriaceae, Pseudomonas spp., staphylococci, and enterococci, respectively. The inhibitory endpoints determined with the Autoreader were as reliable as those determined by visual inspection after 18 h of incubation.
Anti-Bacterial Agents↗
Evaluation of disk approximation and agar dilution induction tests for demonstration of in vitro antagonism of cefotaxime by cefoxitin in Enterobacter species.
Cefoxitin-resistant clinical isolates of Enterobacter spp. demonstrated inducible beta-lactamase activity in 31 of 47 (65.9%) disk approximation tests and in 32 of 52 (63.5%) agar dilution induction tests. Agreement between the two results was only 72.3%, and 80.9% of the strains were positive in at least one induction test. Lack of valid interpretive criteria preclude their routine use in the clinical laboratory.
Cefotaxime↗
Identification and characterization of Yersinia intermedia isolated from human feces.
Since May 1983, our laboratory has, upon request, cultured stools for Yersinia spp. by using direct plating on cefsulodin-irgasan-novobiocin agar and a 3-week cold enrichment procedure. We isolated bacteria identified as Y. intermedia from six adult patients. All isolates were recovered only by the cold enrichment procedure and misidentified as Y. enterocolitica by the API 20E system (Analytab Products, Plainview, N.Y.). Final identification was made on the basis of results obtained with conventional tube biochemical tests. The isolates were tested for the following characteristics associated with virulence in Y. enterocolitica: lack of pyrazinamidase activity, autoagglutinability, presence of a 40- to 50-megadalton plasmid, production of heat-stable enterotoxin, and mouse lethality. All isolates tested had pyrazinamidase activity, and none were autoagglutinable. However, one isolate possessed a 40-megadalton plasmid. None produced enterotoxin or were lethal for mice. Review of the medical histories of the patients revealed that four of the six had diarrhea; however, none had disease typical of that caused by Y. enterocolitica. Our data confirmed the limited pathogenic potential of Y. intermedia and suggested that its isolation was without clinical significance in our patients. Conventional biochemical tests were required for reliable identification of Y. intermedia.
Adult↗
Rapid, direct antibiotic susceptibility testing of blood culture isolates using the Abbott Avantage system.
The Abbott Avantage (AV) is an updated version of the MS-2 system that provides antibiotic-susceptibility results in four to six hours. Although the system compared favorably with reference methods in several laboratory evaluations, little information exists regarding its performance with inocula obtained directly from blood cultures. The authors compared AV and a modified disk-diffusion test using standardized inocula obtained directly from the blood culture bottles for 58 isolates (46 patients). All isolates were also tested by the National Committee for Clinical Laboratory Standards standard disk-diffusion method, using inocula obtained from subcultures of the positive bottles. AV results for 553 antibiotic tests agreed with the direct disk results in 92.6% of the tests, and the agreement with the standard disk results was 88.2%. The concordance between direct and standard disk results was 93.5%. There were 2.2% very major, 1.8% major, and 7.8% minor discrepancies between results obtained with direct AV and standard disk methods. False sensitivity of Klebsiella pneumoniae to ampicillin and carbenicillin and induced clindamycin resistance in staphylococci were noted with AV. When one considers only the clinically meaningful antibiotic-organism combinations, direct AV is an acceptable, rapid alternative to direct disk susceptibility testing.
Anti-Bacterial Agents↗
Electrophoretic and serological characterization of the lipopolysaccharides of Legionella pneumophila.
Lipopolysaccharide (LPS) is a major constituent of the outer membrane of gram-negative bacteria. We used sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteinase-K-digested cell lysates to provide preliminary data on the LPS chemotypes for 20 strains of Legionella pneumophila (serogroups 1 to 8). The profiles of all strains except Chicago 2 (serogroup 6) were similar in the number, spacing, and size distribution of the bands visualized on silver-stained gels and were indicative of smooth LPS. However, compared with the bands from Salmonella minnesota smooth LPS, their banding pattern was much tighter, with three to four legionella bands for every salmonella band. The proteinase K digest of Chicago 2 was unique in that only two widely separated silver-stained bands were seen. LPS profiles of 10 serogroup 1 strains were identical, and the profile of Knoxville 1 was not altered by extensive in vitro passage. We used immunoblotting to investigate the serological specificities of the LPSs. When a rabbit antiserum prepared against a serogroup 1 strain was used to probe nitrocellulose sheets that bound LPS from strains belonging to eight different serogroups, it recognized only the LPS from the homologous serogroup. Similar results were observed with serogroup 2, 4, and 6 antisera. Our data indicate that L. pneumophila has a smooth-type LPS with an unusual banding pattern and that it is a serogroup-specific antigen.
Electrophoresis, Polyacrylamide Gel↗
Major outer membrane protein of Legionella pneumophila carries a species-specific epitope.
A monoclonal antibody (LP3IIG2) directed against a species-specific epitope of Legionella pneumophila is available from Genetic Systems Corp., Seattle, Wash., for use as a diagnostic reagent. Outer membrane protein-rich fractions were prepared from L. pneumophila serogroups 1 to 8 by treatment of cell envelopes with 2% Triton X-100. Immunoblots of sodium dodecyl sulfate-polyacrylamide gels demonstrated that each membrane fraction contained two bands that reacted with LP3IIG2. The monoclonal antibody bound preferentially to a 26,000-molecular-weight band that appears to result from modification of the 29,000-molecular-weight major outer membrane protein.
Antibodies, Monoclonal↗
Reliability of latex agglutination tests for identification of Staphylococcus aureus resistant to oxacillin.
Commercial latex agglutination tests (LATs) for the simultaneous detection of clumping factor and protein A are gaining increased acceptance as a means of identifying Staphylococcus aureus. We evaluated two LATs (Accu-Staph; Carr-Scarborough, Decatur, Ga.; Staphaurex; Wellcome, Dartford, England) with particular emphasis on their ability to correctly identify oxacillin-resistant S. aureus. We tested 59 oxacillin-resistant S. aureus, 136 oxacillin-susceptible S. aureus, and 92 coagulase-negative staphylococcal strains with the two LATs and with thermonuclease, slide clumping factor, tube coagulase, and protein A hemagglutination tests. Clumping factor and protein A were present in 96.9 and 82.1% of our S. aureus strains, respectively. Accu-Staph correctly identified 92.8% and Staphaurex correctly identified 91.3% of S. aureus strains. No significant difference in LAT positivity rates, presence of clumping factor, or presence of protein A was found between oxacillin-resistant and -susceptible S. aureus. Overall, there were 31 false-negative LATs for 20 S. aureus strains, 14 with Accu-Staph and 17 with Staphaurex. Ninety-five percent of these strains possessed either clumping factor or protein A or both when these factors were determined independently. There were five false-positive LATs for four strains of coagulase-negative staphylococci (three Staphylococcus epidermidis and one Staphylococcus warneri), four with Accu-Staph and one with Staphaurex. Clumping factor was present in one S. warneri strain. Thus, the specificities of Accu-Staph, Staphaurex, and the clumping factor test were 95.6, 98.9, and 98.9%, respectively. Our results indicated that LATs identify oxacillin-resistant and -susceptible S. aureus equally well; however, they offer no greater sensitivity or specificity than the clumping factor test for identification of S. aureus.
Coagulase↗
Disc diffusion method to screen for high-level resistance to clindamycin and erythromycin in the Bacteroides fragilis group.
High-level clindamycin resistance in Bacteroides species was investigated by measuring zone sizes surrounding 2 micrograms clindamycin and 60 micrograms erythromycin discs, using a nonstandardized disc diffusion method, and by determining minimal inhibitory concentrations (MIC). The absence of a zone of inhibition surrounding either disc was predictive for all isolates having high-level resistance to both antibiotics (MIC greater than 256 micrograms/ml), characteristic of macrolide-lincosamide-streptogramin (MLS) cross-resistance. Although zone size could not be used as an absolute predictor of MIC, a clindamycin zone diameter of less than 17 mm was suggestive of strains with a moderate level of clindamycin resistance (MIC greater than or equal to 8 micrograms/ml), regardless of erythromycin zone size. Disc diffusion testing using a combination of clindamycin and erythromycin discs can be a useful screening method for detection of clindamycin-resistant Bacteroides species, occurring either alone or as part of the MLS resistance phenotype.
Bacteroides fragilis↗
Genetic structure of populations of Legionella pneumophila.
The genetic structure of populations of Legionella pneumophila was defined by an analysis of electrophoretically demonstrable allelic variation at structural genes encoding 22 enzymes in 292 isolates from clinical and environmental sources. Nineteen of the loci were polymorphic, and 62 distinctive electrophoretic types (ETs), representing multilocus genotypes, were identified. Principal coordinates and clustering analyses demonstrated that isolates received as L. pneumophila were a heterogeneous array of genotypes that included two previously undescribed species. For 50 ETs of L. pneumophila (strict sense), mean genetic diversity per locus was 0.312, and diversity was equivalent in ETs represented by isolates recovered from clinical sources and those collected from environmental sources. Cluster analysis revealed four major groups or lineages of ETs in L. pneumophila. Genetic diversity among ETs of the same serotype was, on average, 93% of that in the total sample of ETs. Isolates marked by particular patterns of reactivity to a panel of nine monoclonal antibodies were also genetically heterogeneous, mean diversity within patterns being about 75% of the total. Both Pontiac fever and the pneumonic form of legionellosis may be caused by isolates of the same ET. The genetic structure of L. pneumophila is clonal, and many clones apparently are worldwide in distribution. The fact that L. pneumophila is only 60% as variable as Escherichia coli raises the possibility that isolates recovered from clinical cases and man-made environments are a restricted subset of all clones in the species as a whole.
Alleles↗
Supplementary rapid biochemical test panel for the API 20E bacterial identification system.
The API 20E Analytical Profile Index typically suggests three or four conventional biochemical tests to complete the identification of strains either identified to genus only or that have multiple genera consistent with the profile number. We compiled a simple panel of eight rapid (4-h) tests that can substitute for the supplementary biochemical tests recommended by Analytab Products (Plainview, N.Y.). The rapid test panel (RTP) consisted of adonitol, cellobiose, lactose, raffinose, rhamnose, and xylose utilization, lysine decarboxylase activity, and motility. A total of 114 consecutive clinical isolates that required additional tests to complete the identifications were each tested with the complete RTP, as well as with the recommended conventional biochemicals. All discordant identifications were resolved by using an expanded series of conventional biochemical tests. Overall, 110 (96%) strains were identified to the correct genus, and 109 (95%) strains were identified to the correct species by using the RTP, as compared with 105 (92%) identified to the correct genus and 90 (79%) identified to the correct species with the recommended tests. The identifications based on the two supplementary test systems did not agree for 7 (6.1%) strains. Four discrepancies were resolved in favor of the RTP, and three were resolved in favor of the recommended tests. We were unable to identify five (4.4%) strains with the recommended tests and only one (0.9%) with the RTP. A majority (86%) of the test strains were identified to the species level with the RTP after only 4 h of incubation.
Bacteriological Techniques↗
Characterization of endemic Providencia stuartii isolates from patients with urinary devices.
Providencia stuartii has emerged as a significant nosocomial urinary tract pathogen. An increase in the number of Providencia isolates from urine cultures prompted an investigation into the possibility of an outbreak due to this organism. A high proportion of patients studied had urinary devices. Four wards were screened at two time periods to ascertain the prevalence of Providencia stuartii in urine cultures. Biotype, serotype, antibiogram and plasmid content were determined for each Providencia isolate. Of 129 patients initially sampled 22.5% were found to harbor Providencia stuartii. Biotyping, serotyping and antibiograms indicated an epidemic strain was not present. Similar results were obtained when the wards were screened a second time, with 25.4% of urine cultures found to contain Providencia stuartii. By plasmid analysis the isolates could be grouped into one of ten profiles. A correlation could be made between urease activity and the presence of a large plasmid. No association however could be made between a particular plasmid profile and antibiogram. The data indicate that an epidemic strain of Providencia stuartii was not present. The source(s) of the endemic Providencia stuartii strains remain unknown.
Bacteriuria↗
Clinical and bacteriologic evaluation of BACTEC resin-containing blood culture medium.
In a retrospective study of 1,143 blood culture sets, BACTEC aerobic (6B) and osmotically stabilized (8B) media were compared individually with resin-containing (16B) medium for the isolation of bacteria from the blood of patients receiving antimicrobial therapy. The 16B medium was found to detect significantly more positive cultures than either 6B (P less than 0.01) or 8B (P less than 0.001). For 22 of 25 isolates of Staphylococcus aureus from 18 patients, 16B medium provided the only means of recovery. All but one of these patients were receiving appropriate antimicrobial therapy, and 16 of 18 had a previous blood culture set positive for S. aureus that did not include a 16B bottle. There was no evidence of a change in antimicrobial therapy in response to a 16B positive culture in these patients. No significant increase in the recovery of other gram-positive or gram-negative bacteria or decrease in the time to radiometric detection of positive cultures as a result of using 16B medium was noted.
Adsorption↗
Plasmids as epidemiological markers in nosocomial Legionnaires' disease.
Plasmid analysis was used in the investigation of an outbreak of nosocomial Legionnaires' disease in four patients. Serogroup 1 strains were isolated from two patients, the air-conditioning cooling tower, and two hot-water tanks. All serogroup 1 strains contained two plasmids with approximate molecular masses of 21 and 48 megadaltons (Mdal). The serogroup 1 strain found in the cooling-tower isolate also contained an additional 1.9 Mdal-plasmid. Restriction-endonuclease analysis of the 21-Mdal plasmid that was present in patient and hot water-tank isolates revealed identical EcoRI and HaeIII fragment patterns. Digestion of the similarly sized plasmid in the cooling-tower isolate resulted in a unique fragment pattern. The data provide direct bacteriologic evidence implicating the hot-water tanks rather than the cooling tower as the source of the infecting strain.
Cross Infection↗
Enzymatic activities of Legionella pneumophila and Legionella-like organisms.
The API ZYM system was used to investigate enzymatic activities of Legionella pneumophila and other Legionella-like organisms. Leucine aminopeptidase, alkaline and acid phosphatase, butyrate and caprylate esterase, and phosphoamidase activities were consistently detected in all strains tested. No evidence of myristate lipase, trypsin, chymotrypsin, or glycosidase activity was found.
Acid Phosphatase↗
Binding of radiolabeled Staphylococcus aureus delta-toxin to human erythrocytes.
The addition f [3H]isoleucine to a chemically defined medium resulted in the production of delta-toxin (DT) with a high specific radioactivity (0.47 microCi/mg). The purified tritium-labeled toxin ([3H]DT) was found to migrate in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a single band with a molecular weight of 1,600. Upon electrofocusing, [3H]DT yielded one major peak (pI = 5.90) and two minor peaks (pI = 5.10, 6.95) of radioactivity. The percentage of [3H]DT associated with pelleted fractions of intact erythrocytes or erythrocyte ghosts remained fairly constant over a 100-fold range of toxin concentrations. Erythrocyte ghosts, however, bound more [3H]DT than did intact erythrocytes when exposed to the same concentration of toxin. Erythrocytes maintained in isotonic sucrose were more susceptible to toxin than erythrocytes suspended in saline, but did not bind more [3H]DT. The binding of [3H]DT to erythrocyte ghosts was found to be temperature dependent from 0 to 20 degrees C but was constant from 20 to 50 degrees C.
Bacterial Toxins↗