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Biomedical subjects

P K Yu

Publications and source records attributed to P K Yu.

At least 73 records · Page 4Linked to original sources
PubMed1973

Comparative in vitro activity of three aminoglycosidic antibiotics: BB-K8, kanamycin, and gentamicin.

Kanamycin, BB-K8, and gentamicin were tested in parallel against 1,037 bacterial strains isolated from clinical material. The activity of BB-K8 at 20 mug/ml was comparable to that of gentamicin at 8 mug/ml against Pseudomonas aeruginosa and against Enterobacteriaceae, with the exception of gentamicin-resistant strains of Proteus rettgeri and Providencia stuartii, in which case the activities of BB-K8 and kanamycin were the same. BB-K8 exhibited little or no activity against streptococci. The activity of BB-K8 was affected by pH and inoculum size. A regression graph for inhibition data with a 10-mug disk of BB-K8 was developed, and synergistic activity of penicillin and BB-K8 against Streptococcus faecalis was tested.

Aminobutyrates↗
PubMed1972

In vitro antibacterial activity of spectinomycin.

The in vitro inhibitory and bactericidal activities of spectinomycin hydrochloride were tested against a variety of bacteria. The antibiotic was inhibitory at 31.2 mug/ml to most strains of Escherichia coli, Klebsiella, Enterobacter, and Staphylococcus epidermidis. Concentrations of antibiotic exhibiting bactericidal activity exceeded the inhibitory concentration by at least fourfold. Regression graphs were plotted for results obtained with 30-, 100-, 200-, and 300-mug spectinomycin discs; tentative interpretative standards are proposed.

Bacteria↗
PubMed1972

Evaluation of the Auxotab Enteric 1 System for identification of Enterobacteriaceae.

An evaluation of the accuracy and convenience of the Auxotab Enteric 1 System for identification of Enterobacteriaceae was performed with 160 bacteria. Identification at the species level was correct in 134 (83.8%) instances and at the generic level in 144 (90%) instances. Sixty strains failed to achieve the minimal concentration of organisms required to complete the identification process within 7 hr. The system was judged to be laborious and to present a potential hazard to those working with it.

Bacteriological Techniques↗
PubMed1972

Evaluation of modified R-B system for identification of members of the family Enterobacteriaceae.

In a paired, double-blind study, the modified ("Beckford tube") R-B system was compared with conventional bacteriological procedures for the identification of members of the family Enterobacteriaceae from clinical isolates and stock cultures. The tests in the R-B system yielding positive reactions comparable to those predicted by Ewing's taxonomic classification of Enterobacteriaceae were production of hydrogen sulfide and presence of lysine and ornithine decarboxylasè activities. The test reactions in the R-B system found to be comparable to those in the conventional method were fermentation of glucose, hydrogen sulfide production, and lysine and ornithine decarboxylase activities. The production of gas from glucose was positive in the R-B system more often than in the conventional method; however, the motility test and the production of indole were positive less often in the R-B system. Adequate preliminary identification of the Enterobacteriaceae with the R-B system is enhanced if Simmons' citrate and Christensen's urea tests are used concomitantly. These findings emphasize the manufacturer's instructions that, in interpretation of results, colonial morphology and biochemical reactions must be used concurrently to make an accurate identification.

Bacteriological Techniques↗
PubMed1971

Radiometric method for detection of bacteremia.

A study was performed with simulated blood cultures to evaluate the production of (14)CO(2) as an index of bacterial growth. With a range of inoculum sizes from 4 to 4,250 colony-forming units, it was not possible to detect (14)CO(2) within 6 hr after inoculation in 59 separate experiments. In a limited trial with patients' blood cultures, the radiometric method failed to provide any earlier evidence of bacteremia than did routine broth cultures.

Bacteriological Techniques↗
PubMed1971

Evaluation of the enterotube system for identification of members of the family Enterobacteriaceae.

The Enterotube system was evaluated, in parallel with conventional bacteriological procedures for the identification of members of the family Enterobacteriaceae, by using bacterial strains from a variety of clinical specimens and from stock cultures. Excellent agreement between the two test systems was obtained with the following reactions: hydrogen sulfide, indole, Simmons' citrate, glucose, and lactose. Agreement was not as good (<85%) with the urea, phenylalanine deaminase, and dulcitol reactions. The Enterotube lysine decarboxylase test was unsatisfactory. The Enterotube method will correctly identify strains of the family Enterobacteriaceae approximately 50% of the time; if identification only as Klebsiella-Enterobacter-Serratia group is needed, the method will be correct 85% of the time. On the basis of this evaluation, the Enterotube system appears to be both simple and rapid for the presumptive identification of these bacteria. Because of the limited usefulness of the lysine decarboxylase test, the results obtained by this test system are less reliable than those obtained by conventional methods.

Bacteriological Techniques↗
PubMed1971

Evaluation of accuracy of multitest micromethod system for identification of Enterobacteriaceae.

The Analytab system of 20 biochemical tests for identification of Enterobacteriaceae was evaluated in parallel with conventional tests on 128 Enterobacteriaceae, 5 Aeromonas, and 1 Yersinia enterocolitica. The results of tests for H(2)S and indole production, citrate utilization, lysine and ornithine decarboxylase, arginine dihydrolase, nitrate reduction, beta-galactosidase, and fermentation of arabinose, rhamnose, mannitol, and glucose showed almost complete agreement between the two systems. Eighty-eight per cent of Enterobacteriaceae were correctly speciated with the Analytab system; on repeat testing with heavier inocula of organisms failing to ferment glucose initially, the proportion of Enterobacteriaceae correctly speciated became 93%.

Aeromonas↗
PubMed1970

In vitro antibacterial activity of minocycline and effect of agar medium utilized in its susceptibility testing.

The in vitro activity of minocycline against 1,028 bacterial strains was determined in parallel in Mueller Hinton Agar and Trypticase Soy Agar. The broad antibacterial effect of minocycline against gram-positive cocci and gram-negative bacilli is confirmed. Minimal inhibitory concentrations for gram-positive bacteria in Mueller Hinton Agar were at least twofold less than in Trypticase Soy Agar. Minimal inhibitory concentrations for gram-negative bacilli in Mueller Hinton Agar were usually fourfold less than in Trypticase Soy Agar.

Acinetobacter↗
PubMed1970

Regression curve analysis of cephalosporin activity.

Regression lines were calculated for cephalothin, cephalexin, and cephaloridine by relating zone diameters of inhibition to minimal inhibitory concentrations (MIC) obtained in Mueller-Hinton agar and in Trypticase Soy Agar. A regression line was calculated for cephaloglycin by obtaining MIC values in Trypticase Soy Agar at pH 6.6. Regression lines calculated from MIC values in Mueller-Hinton agar were practically superimposable on those based on MIC values in Trypticase Soy Agar. Organisms susceptible by disc testing to cephalothin were usually susceptible to cephalexin and cephaloridine.

Agar↗
PubMed1970

Hydrogen sulfide-negative variant of Citrobacter.

The characteristics of 25 hydrogen sulfide-negative strains of Citrobacter were studied. The majority of isolates were from the respiratory tract and usually were of indeterminate clinical significance. All strains were highly susceptible to polymyxin B, gentamicin, kanamycin, nalidixic acid, and nitrofurantoin.

Ampicillin↗
PubMed1970

Identification of members of the family Enterobacteriaceae by the R-B system.

The R-B system was evaluated in parallel with conventional bacteriological procedures for the identification of members of the family Enterobacteriaceae by using bacterial strains from a variety of clinical specimens and from stock cultures. The R-B tests found to be reliable were, in decreasing order, the reactions for phenylalanine deaminase, hydrogen sulfide, and indole, the production of gas from glucose, and the decarboxylation of ornithine. The reactions in the R-B system found to be unreliable were motility, the decarboxylation of lysine, and the fermentation of both glucose and lactose. In addition, the reactions of the R-B system were more difficult to read and interpret than those of the conventional system. On the basis of this evaluation, it was concluded that the R-B system is not an acceptable alternative to the conventional methods in the identification of the Enterobacteriaceae.

Bacteriological Techniques↗
PubMed1969

Characterization of Micrococcaceae isolated from clinical sources.

The characterization of 556 Micrococcaceae isolates from various clinical sources has been presented. The incidence of coagulase-negative mannitol-positive staphylococci was 3.2% and that of coagulase-positive mannitol-negative staphylococci was 1.6%. There appears to be insufficient justification for the routine reporting of staphylococcal variants from a general bacteriology laboratory, and biotyping should be reserved for special circumstances.

Bacteria↗
PubMedDate not supplied

Increased efficiency of stool culture for the detection of Salmonella and Shigella.

The Wampole Bactigen Salmonella-Shigella Latex Agglutination Test (SSLA) (Wampole Laboratories, Cranbury, New Jersey) was evaluated as a possible substitute for blind subculture of selenite broths from stool cultures. Recovery rates of Salmonella and Shigella from eosin-methylene blue (EMB) agar were reviewed to determine if this medium could be eliminated from primary stool culture. Salmonella was detected in 17 of 822 stools by both SSLA and culture. There were 52 false-positive SSLA for Salmonella (sensitivity 100%, specificity 93%). Of three Shigella isolated on culture, one was SSLA positive, one was SSLA negative, and one was negative by both SSLA and subculture of selenite broth. There were eight false-positive SSLA for Shigella (specificity 99%). Of 50 Salmonella and 11 Shigella isolated from 6200 stools in 1.5 years, two Shigella were isolated on EMB only. The SSLA test is a useful screening test for Salmonella. By eliminating unnecessary subcultures of selenite broth, it reduces turnaround time by 24 hr for negative stool cultures. The combination of primary culture with SSLA screening of enrichment broth should be adequate for the detection of Salmonella and Shigella from stool specimens. Our data suggest that EMB or other differential medium should be retained for primary culture to enhance detection of Shigella.

Culture Media↗
PubMedDate not supplied

Evaluation of calcofluor white stain for detection of Pneumocystis carinii.

A rapid calcofluor white (CFW) stain for detecting Pneumocystis carinii was evaluated prospectively. Eighty-nine bronchoalveolar lavage (BAL) specimens, 21 open-lung biopsy (OLB) tissues, 2 induced sputums, 1 expectorated sputum, 2 tracheal secretions, and 1 bronchial secretion from 102 patients were examined for P. carinii cysts by both the CFW stain and a modified methenamine silver (MS) stain. Twenty episodes of P. carinii pneumonia were detected: 19 of these episodes were detected by CFW stain, and 16 of those episodes were detected by MS stain. Discrepancies between the two staining methods were resolved by review of the clinical histories and, in one case, by testing an OLB specimen. Neither staining procedure gave false-positive results with any specimen. More cysts were detected in CFW-stained specimens than in MS-stained specimens (p = 0.05). CFW stain is a simple, rapid, and inexpensive method for detecting P. carinii in clinical specimens and is at least as sensitive as MS stain.

Adolescent↗
PubMedDate not supplied

Application of quadFERM+ for the identification of fastidious gram-positive and gram-negative bacilli.

The 2-hr quadFERM+ kit (qF) (Analytab Products, Plainview, NY) was compared with conventional tube tests for the identification of the HACEK bacteria (Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae), other Haemophilus and Kingella spp., Capnocytophaga, Corynbacterium, and Moraxella spp. Test results were identical for 296 comparisons with 74 isolates (74%). In the remaining 104 comparisons for 26 isolates, 50 reactions were identical, and qF produced a positive result in 46 of 54 discrepancies.

Actinobacillus↗