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F C Tenover

Publications and source records attributed to F C Tenover.

At least 181 records · Page 10Linked to original sources
PubMed1985

Development of two DNA probes for differentiating the structural genes of subclasses I and II of the aminoglycoside-modifying enzyme 3'-aminoglycoside phosphotransferase.

Two DNA probes were developed to screen for the genes encoding 3'-aminoglycoside phosphotransferase activity in gram-negative bacilli. The 3'-I phosphotransferase [APH(3')I] probe was subcloned from Tn903; the APH(3')II probe was subcloned from Tn5. Each probe proved to be specific for genes corresponding to its own APH(3') subclass and did not hybridize with DNA from other classes when tested at high stringency by either Southern hybridization or dot-blot hybridization methods. The APH(3')I probe hybridized to DNA obtained from organisms demonstrating APH(3')I activity as measured by the phosphocellulose paper binding assay (PPBA) as well as to DNA from organisms reported to have both APH(3')I and APH(3')II activity by PPBA. This probe did not hybridize to DNA from organisms showing only APH(3')II activity by PPBA. The APH(3')II probe demonstrated homology with DNA from organisms showing APH(3')II activity by PPBA but not with DNA from organisms showing APH(3')I activity or both APH(3')I and APH(3')II activity by PPBA. We conclude that organisms previously believed to contain both APH(3')I and APH(3')II genes based on PPBA contain in fact only the APH(3')I gene.

Autoradiography↗
PubMed1985

Comparison of three DNA hybridization methods for detection of the aminoglycoside 2"-O-adenylyltransferase gene in clinical bacterial isolates.

Two rapid DNA hybridization methods in which whole-cell lysates fixed to nitrocellulose were used were compared with Southern hybridization of purified plasmid or chromosomal DNA for the ability to identify the 2"-O-adenylyltransferase [ANT(2")] gene in 42 enzymatically defined isolates of gram-negative bacilli. A DNA restriction fragment isolated from an ANT(2") gene cloned into pBR322 and radiolabeled with 32P was used as the probe in all three procedures. Under conditions of high stringency, agreement was obtained between the Southern hybridization method and detection of the ANT(2") enzyme by the phosphocellulose paper binding assay or resistance phenotype in 39 of the 42 strains tested. By using these characterized strains, colony hybridization was shown to be unsatisfactory as a rapid technique for detecting the ANT(2") gene, due to the high number of false-positive and -negative signals obtained. Compared with Southern hybridization, however, spot hybridization (SPH) proved highly reliable for detecting the ANT(2") gene in both members of Enterobacteriaceae and Pseudomonas aeruginosa harboring R factors ranging in size from 23 to 150 kilobases. The relatively low copy number of the 150-kilobase plasmids decreased the sensitivity of SPH, necessitating a minimum cell density of 5 X 10(6) cells per spot. SPH proved to be a very useful method for rapidly screening large numbers of clinical isolates for this resistance determinant.

Collodion↗
PubMed1985

Use of auxotyping for epidemiological studies of Campylobacter jejuni and Campylobacter coli infections.

A chemically defined medium developed for Neisseria gonorrhoeae was modified to support the growth of Campylobacter jejuni and Campylobacter coli. A total of 76 isolates of C. jejuni and 14 isolates of C. coli were tested on this medium, which was designated Campylobacter defined medium (CDM), over a 3-month period. Although none of the C. coli isolates appeared to require amino acids, 51% of the C. jejuni tested required one and 7% required multiple amino acids for growth. An analysis of isolates obtained from three household outbreaks of campylobacteriosis demonstrated that auxotyping identified the epidemic strain within each outbreak. Among 70 isolates of C. jejuni examined, no correlation could be drawn between a specific serotype and auxotype or between auxotype and plasmid profile.

Amino Acids↗
PubMed1985

Confirmation of Legionella pneumophila cultures with a fluorescein-labeled monoclonal antibody.

We compared a fluorescein-labeled monoclonal antibody directed against an outer membrane protein of Legionella pneumophila (Genetic Systems Corp. [GSC], Seattle, Wash.) with a similarly labeled polyclonal reagent (L. pneumophila serogroups 1 to 6, poly; BioDx, Inc., Denville, N.J.) for the confirmation of L. pneumophila isolates grown in culture. Duplicate suspensions of 52 organisms, including 21 L. pneumophila and 8 non-L. pneumophila species of legionella, were placed on individual glass slides, fixed, and stained with both reagents, and the results were compared. Both antisera correctly identified all L. pneumophila serogroups 1 to 6, but only the GSC reagent produced definitive staining of the L. pneumophila isolates of serogroups 7, 8, and 9. Additionally, the GSC reagent produced more uniform staining patterns around the legionella bacilli and displayed little background fluorescence when compared with the BioDx reagent.

Antibodies, Bacterial↗
PubMed1985

Comparison of the automicrobic system, acridine orange-stained smears, and gram-stained smears in detecting bacteriuria.

We compared the accuracy of the Gram-stained smear, the acridine orange-stained smear, and the AutoMicrobic system (AMS; Vitek Systems, Inc., Hazelwood, Mo.) in screening for bacteriuria, as detected by conventional cultures. For 1,024 clinical specimens, results with the acridine orange-stained smear and the Gram-stained smear were very similar. When read for the presence of one or more microorganisms or leukocytes per 20 oil immersion fields, both smears were highly sensitive (92.1 and 93.3%, respectively) and moderately specific (70.0 and 61.7%, respectively). Sensitivity was greater for specimens yielding greater than or equal to 10(5) CFU/ml (96.1 and 98.9%, respectively) than for those with 10(3) to 10(4) CFU/ml (81.4 and 78.0%, respectively). Preliminary classification based upon the tinctorial and morphological characteristics of the Gram-stained smear was compatible with culture results in nearly all cases. The accuracy of the Gram-stained smears was not influenced by special cleaning of the microscopic slides, or the level of expertise of the microscopist. For 715 specimens, the sensitivity of the AMS in detecting bacteriuria (91.5%) was very similar to that of the stained smears (92.1 and 95.7%, respectively), but the specificity was significantly higher (83.2% versus 42.6 and 70.0%). Detection of microorganisms by the AMS took an average of 6.3 +/- 3.0 h. These data suggest that the Gram-stained smear is easily interpreted, very sensitive, acceptably specific, and still the optimal rapid method for screening for bacteriuria in most clinical microbiology laboratories.

Acridine Orange↗
PubMed1985

Specimen volume versus yield in the BACTEC blood culture system.

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%).

Bacteriological Techniques↗
PubMed1985

Plasmid fingerprinting. A tool for bacterial strain identification and surveillance of nosocomial and community-acquired infections.

Plasmid fingerprinting provides a rapid and dependable means of identifying bacterial isolates of the same strain. The stability, wide distribution, and diverse nature and size of extrachromosomal elements make it suitable for virtually all bacterial genera. There are many different procedures available for plasmid screening, and the one chosen depends primarily on the types of organisms to be analyzed. Some procedures are better suited to gram-positive organisms; others are better for visualizing the very large plasmids often seen in Pseudomonas and Rhizobium species. The key to the plasmid fingerprinting technique is agarose gel electrophoresis. In this step of the technique, it is important to differentiate open circular from closed circular forms of plasmids and to recognize the "smile effect." Plasmid fingerprinting can be utilized for epidemiologic studies of both nosocomial and community-acquired infections. The use of restriction endonuclease analysis can greatly enhance the ability of the investigator to differentiate strains that harbor only a single plasmid. Plasmid fingerprinting often provides the only differential characteristic for strains involved in epidemics.

Bacteria↗
PubMed1984

Vibrio parahaemolyticus gastroenteritis. An outbreak associated with raw oysters in the Pacific northwest.

During a 3-month period in the late summer and fall of 1981, six cases of gastroenteritis and one wound infection due to Vibrio parahaemolyticus were reported to public health agencies in Washington and Oregon. An investigation revealed that all of the gastroenteric illnesses were associated with eating raw oysters; that oysters eaten by five of the six patients were harvested at four divergent sites at Willapa Bay, Washington, a large commercial growing area; and that the V. parahaemolyticus isolates from those five patients were all Kanagawa positive, belonged to serotype 04:K12, and exhibited an atypical biochemical reaction, urea hydrolysis. No further cases linked to Willapa Bay oysters have been reported, and the infecting strain could not be found in sediment samples from the bay in February 1982. Thus, even though the origin of this self-limiting outbreak is obscure, the investigation demonstrated that the geographic distribution of V. parahaemolyticus infection in the United States includes the Pacific seacoast . Furthermore, oysters must be considered, along with crabs, shrimp, and lobster, as a vehicle of transmission of this infection in the United States.

Adult↗
PubMed1984

Development of a DNA probe for the structural gene of the 2"-O-adenyltransferase aminoglycoside-modifying enzyme.

Analysis of aminoglycoside-resistant Enterobacteriaceae isolated from patients at the Seattle Veterans Administration Medical Center indicated that a single 68-kilobase R factor was responsible for the epidemic spread of low-level resistance to gentamicin, kanamycin, and tobramycin. An examination, by means of the phosphocellulose paper binding assay, of resistant strains carrying this R factor resulted in the identification of a 2"-O-adenyltransferase [ANT(2")]-modifying enzyme. This enzyme was later detected in strains containing 150-kilobase plasmids. For more convenient monitoring of the dissemination of the ANT(2") gene among clinical isolates at the medical center, a DNA probe was developed by cloning of the ANT(2") structural gene from the 68-kilobase factor into pBR322. A 310-base pair Ava I restriction fragment isolated from the interior of the cloned ANT(2") gene was radiolabeled and used in Southern hybridization gels as a probe for plasmids isolated from aminoglycoside-resistant organisms. The probe proved to be highly specific and was more sensitive than enzymologic techniques for detection of the ANT(2") gene in clinical isolates with complex aminoglycoside resistance phenotypes.

Aminoglycosides↗
PubMed1983

Characterization of a chimeric beta-lactamase plasmid of Neisseria gonorrhoeae which can function in Escherichia coli.

A chimeric beta-lactamase encoding plasmid, containing the 4.4 Mdal beta-lactamase plasmid and the 2.6 Mdal cryptic plasmid of Neisseria gonorrhoeae has been characterized by physical and biological methods. Digestion with restriction enzymes indicates the presence of the following restriction sites: 1 site: AccI, AvaI, HgiAI, HincII, MstI, PstI, PvuII, XbaI and XorI; 2 sites: HindIII and BamHI; 3 sites: BclI, Sau96I and AvaII; 6 sites: HinfI; greater than 8 sites: AluI, BbvI, DdeI, HgaI, HhaI, HpaII, MspI, Sau3A, TacI and TaqI. No restriction sites were found for the following: BglI, BglII, BstEII, EcoRI, EcoRII, HpaI, HphII, KpnI, SacI, SalI, SmaI, SstI, SstII, and XhoI. Five plasmid specific proteins have been identified by DNA directed in vitro protein synthesis (43K, 41K, 30K, 16K and 14K). The location on the physical map of the coding regions for each of these proteins has been determined by the following methods: using plasmid DNA restricted by various enzymes in an in vitro protein synthesis system; identifying promoter-containing regions by digesting plasmid DNA with DdeI, adding RNA polymerase and then determining which fragments are retained by nitrocellulose. This plasmid contains both parental phenotypes in that it encodes penicillin resistance and possesses the sequence necessary for uptake in the gonococcus. Transformation data indicate that this plasmid can function in both E. coli and N. gonorrhoeae and that growth in E. coli has no effect on the plasmid's ability to transform the gonococcus.

Bacterial Proteins↗
PubMed1983

Isolation of plasmids encoding tetracycline resistance from Campylobacter jejuni strains isolated from simians.

Fifteen isolates of tetracycline-resistant Campylobacter jejuni were recovered from stool samples of cynomologous monkeys (Macaca fascicularis) housed at the University of Washington Primate Research Center, Seattle. Resistance was associated with carriage of a 38-megadalton plasmid which was transmissible to other strains of C. jejuni but not to Escherichia coli. Seven isolates also contained a 2.6-megadalton plasmid which was phenotypically cryptic.

Animals↗
PubMed1982

High correlation of the presence of methyladenine in Neisseria gonorrhoeae DNA with the AHU auxotype.

Strains of Neisseria gonorrhoeae were tested for the presence of methyladenine in the DNA sequence GATC by using the site-specific restriction endonucleases MboI and DpnI. It was found that 43 of 83 strains tested contained methylated DNA. When methylation was compared with the auxotype of the organism, 35 of 35 strains with the AHU (arginine-, hypoxanthine-, and uracil-requiring) auxotype and 8 of 48 strains with other auxotypes contained methyladenine. When the incidence of methylation in strains isolated from patients suffering from disseminated gonococcal infection was compared with that in strains isolated from patients suffering from uncomplicated gonococcal infection, no correlation with methylation and disseminated gonococcal infection was observed.

Adenine↗
PubMed1982

Marker rescue by a homologous recipient plasmid during transformation of gonococci by a hybrid Pcr plasmid.

A 42-kilobase hybrid Pcr plasmid (pFA14) was formed when the naturally occurring 7.2-kilobase Pcr plasmid pFA3 was introduced by transformation into a competent gonococcal recipient containing the 36-kilobase conjugative plasmid pFA2 (Sox et al., J. Bacteriol. 138:510-518). Analysis of the structure of pFA14 showed that it was a stable recombinant between pFA3 and pFA2. The transformation efficiency of pFA14 was increased 300- to 10,000-fold by the presence in isogenic recipients of the homologous plasmid pFA2. The presence of a homologous plasmid in the recipient also markedly increased the likelihood of recovery of intact donor-size Pcr plasmids in the transformants. The presence of pFA2 had no effect on the competence of piliated or nonpiliated gonococci for transformation by either linear chromosomal DNA or a nonhomologous Pcr plasmid. Increased transformation efficiency of the hybrid Pcr plasmid pFA14 may have been due to recombination between the nicked or linearized donor plasmid and the homologous recipient plasmid (marker rescue).

Chromosomes, Bacterial↗
PubMed1980

Physical map of the conjugal plasmid of Neisseria gonorrhoeae.

The 24.5-megadalton plasmid of Neisseria gonorrhoeae is required for transfer of R-factors and possibly chromosomal markers during conjugal matings between gonococcal strains. We constructed a physical map of one such plasmid, pLE2451, using EcoRI, BglII, and HincII site-specific restriction endonucleases. The patterns of deoxyribonucleic acid digestion obtained with this plasmid were identical to those obtained with three other plasmids of similar size.

Conjugation, Genetic↗
PubMedDate not supplied

Factors affecting the clinical value of microscopy for acid-fast bacilli.

In order to assess the clinical value of microscopy for acid-fast bacilli (AFB), the results of 3,207 clinical specimens submitted for mycobacterial smear and culture were analyzed. Mycobacteria grew from 176 (5.5%) of the specimens, 95 (54%) of which were Mycobacterium tuberculosis. Although the overall sensitivity of the smear was low (33%), 65% of respiratory specimens yielding M. tuberculosis had positive AFB smears. Furthermore, 96% of patients with pulmonary tuberculosis from whom more than one specimen was processed had at least a single positive AFB smear. Smear sensitivity correlated well with quantitative growth; 89% of specimens yielding greater than or equal to 50 colonies per slant were smear positive. Specificity of the AFB smear was high; 89% of smear-positive specimens had positive cultures. After the results from culture-negative patients known to have active tuberculosis were eliminated from the analysis, the specificity of a positive smear rose to 98.3%. When the results of all specimens from each patient were considered in toto, the AFB smear had a predictive value of greater than or equal to 96%.

Aniline Compounds↗
PubMedDate not supplied

Construction and characterization of chimeric beta-lactamase plasmids of Neisseria gonorrhoeae with altered ability to be mobilized during conjugation.

A series of chimeric plasmids derived from the transfer factor, beta-lactamase-encoding R factor, and cryptic plasmid of Neisseria gonorrhoeae was constructed. Two of these plasmids, each lacking a 1.9-kilobase-pair (kb) HinfI fragment, could not be mobilized by the 40-kb gonococcal transfer factor to recipient strains of N. gonorrhoeae or Escherichia coli during conjugation. The proteins encoded by both the naturally occurring and chimeric plasmids were examined with an E. coli cell-free transcription-translation system and in E. coli maxicells. Six plasmid-specific proteins were identified when DNA from a naturally occurring 7.1-kb R factor was used as template. A small protein (16,000 daltons), which is apparently not encoded by the two plasmids lacking the 1.9-kb HinfI fragment, appears to be necessary for plasmid transfer during conjugation.

Bacterial Proteins↗