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Biomedical subjects

P K Yu

Publications and source records attributed to P K Yu.

At least 55 records · Page 3Linked to original sources
PubMed1992

Urinary tract infection caused by nontyphoidal Salmonella: report of 30 cases.

Thirty cases of nontyphoidal Salmonella bacteriuria were identified by review of cultures performed at the Mayo Clinic (Minn.) from 1985 to 1989 and at the Federal Public Health Laboratory Innsbruck (Austria) from 1979 to 1989. All patients had symptoms of an acute urinary tract infection (UTI). In 24 cases nontyphoidal Salmonella was the sole pathogen isolated. Only 1 patient presented with concomitant gastroenteritis and 2 had experienced episodes of diarrhea during the weeks before the UTI, but 15 patients had positive stool cultures in the absence of a gastrointestinal illness. Among all positive urine cultures at the Mayo Microbiology Laboratory, 0.015% were positive for nontyphoidal Salmonella; at the Federal Public Health Laboratory Innsbruck, 0.024% of organisms cultured from urine were nontyphoidal salmonellae. In the majority of our patients, Salmonella UTI did not differ clinically from UTI caused by other members of the Enterobacteriaceae; only in renal transplant recipients was the course of genitourinary salmonellosis more serious. While some urinary isolates of nontyphoidal Salmonella may be fecal contaminants, all 30 isolates recovered from urine during this study were considered to be the cause of symptomatic UTI.

Adolescent↗
PubMed1990

Results of a 6-month survey of stool cultures for Escherichia coli O157:H7.

Escherichia coli O157:H7 is a recently recognized enteric pathogen that causes acute hemorrhagic colitis. Although the infection is usually self-limited, it may be complicated by hemolytic uremic syndrome and thrombotic thrombocytopenic purpura. At our institution, stool specimens are now routinely cultured for this organism. To determine the prevalence of E. coli O157:H7-associated diarrhea in our patient population, we surveyed all submitted stool cultures for 6 months for this organism. Specimens were screened for non-sorbitol fermenting E. coli and confirmed by slide-agglutination and immobilization testing. Of 2,164 specimens, 10 yielded E. coli O157:H7. It was the fourth most common bacterial stool pathogen found. Bloody diarrhea and abdominal pain were the most common symptoms of the infected patients. E. coli O157:H7 causes sporadic infections in our patient population and should be considered in the differential diagnosis of acute hemorrhagic colitis.

Adolescent↗
PubMed1989

Wound infection caused by Branhamella catarrhalis.

Branhamella catarrhalis was isolated from sputum, tracheal secretions, and a nonhealing and infected thoracic surgical wound in a 59-year-old woman who had a history of a chronic, interstitial fibrosis and who had undergone an open lung biopsy procedure. The patient's upper respiratory tract was the likely source of the organism. To our knowledge, this is the first report of a wound infection caused by B. catarrhalis.

Biopsy↗
PubMed1988

Evaluation of TestPack Strep A for the detection of group A streptococci in throat swabs.

The performance of TestPack Strep A (Abbott Laboratories), a rapid enzyme immunoassay, was compared with a culture-based method for the detection of group A streptococci in 648 throat swabs. The rapid test correctly detected 99 of the 128 positive and 511 of the 520 negative specimens, a sensitivity of 77% and a specificity of 98%. Although highly specific, TestPack Strep A is less sensitive than culture techniques for the detection of group A streptococci in throat swabs.

Evaluation Studies as Topic↗
PubMed1988

Haemophilus paraphrophilus frontal lobe abscess: case report.

We report a case of cerebral abscess due to Haemophilus paraphrophilus in a 51-year-old man who was otherwise healthy and had no cardiac abnormality. A source for the infection was not definitively identified; however, the patient had had dental manipulations 2 weeks before the onset of symptoms, and an oral source is probable. The patient was treated successfully with antibiotics after removal of the abscess. Bacteriological studies are discussed.

Ampicillin↗
PubMed1986

In vitro activity of an orally administered cephalosporin, LY164846, against potentially pathogenic respiratory and dermal bacterial isolates.

The antibacterial activity of LY164846, a new orally administered semisynthetic cephalosporin, was compared with that of amoxicillin-clavulanic acid against 492 potentially pathogenic respiratory tract and dermal isolates. Against groups A, B, and G streptococci; pneumococci; staphylococci (other than methicillin resistant); Haemophilus influenzae; Branhamella catarrhalis; and meningococci, the MICs for 90% of strains tested of LY164846 and amoxicillin-clavulanic acid were less than or equal to 4 and less than or equal to 1 microgram/ml, respectively. LY164846 was equally active against beta-lactamase-positive and -negative strains of Haemophilus and Staphylococcus. MBC to MIC ratios of LY164846 versus H. influenzae were less than or equal to 2, while those with Staphylococcus aureus were more difficult to determine because of skipped tubes or paradoxic effects. There were minimal inoculum, pH, or serum effects on LY164846 activity against H. influenzae and S. aureus. In time-kill studies, LY164846 and amoxicillin-clavulanic acid at double MICs were 99.9 to 100% bactericidal to H. influenzae in 24 h; two times the MIC of LY164846 and four times the MIC of cephalexin were 99.9 to 100% bactericidal to S. aureus in 24 h. Based on error-rate-bounded analysis, the following interpretative guidelines for 30-micrograms LY164846 disk diffusion test diameters are suggested: greater than or equal to 19 mm, susceptible (MIC, less than or equal to 4 micrograms/ml); 16 to 18 mm, intermediate (MIC, greater than 4 but less than or equal to 8 micrograms/ml); less than or equal to 15 mm, resistant (MIC, greater than 8 micrograms/ml).

Amoxicillin↗
PubMed1986

Lack of antibacterial activity of pentoxifylline.

Pentoxifylline was inactive when tested against 70 fresh clinical bacterial isolates, as well as when tested alone and in combination with erythromycin, vancomycin, or rifampin against Escherichia coli PC1349 (wild type) and its heptose-deficient outer membrane mutant E. coli PC2040. No antibacterial activity of pentoxifylline or its metabolites could be detected in sera from patients receiving pentoxifylline or its metabolites could be detected in sera from patients receiving pentoxifylline.

Bacteria↗
PubMed1985

Antistreptococcal activity of Sch 34343, a new penem antibiotic.

The in-vitro activity of Sch 34343 was compared with that of penicillin and cefotaxime against clinical isolates of streptococci. Sch 34343 was highly active against Streptococcus pneumoniae, viridans streptococci, streptococci of groups A, B, C and G, and Str. bovis. Ninety per cent of these strains were inhibited by less than or equal to 0.25, less than or equal to 0.12 and less than or equal to 0.06 mg/l of Sch 34343, penicillin and cefotaxime respectively. Activity of Sch 34343 against Str. faecalis was only moderate. Sch 34343 had very good bactericidal activity against group B streptococci, and showed high MBC/MIC ratios against penicillin-tolerant viridans streptococci and Str. faecalis. Sch 34343, 20 mg/l, and gentamicin, 4 mg/l, were synergistic against both of the penicillin-tolerant viridans streptococci, and one-third of the Str. faecalis strains.

Anti-Bacterial Agents↗
PubMed1983

Bactericidal and synergistic activity of moxalactam alone and in combination with gentamicin against Pseudomonas aeruginosa.

The bactericidal activity of moxalactam, alone and in combination with gentamicin, was studied with macrobroth two-dimensional checkerboard and killing curve techniques against gentamicin-resistant and -susceptible strains of Pseudomonas aeruginosa. Moxalactam was bactericidal at concentrations equal to or at least two to four times its inhibitory concentrations. Synergy at clinically applicable concentrations of moxalactam and gentamicin occurred with 6 of 14 gentamicin-resistant strains and 4 of 4 gentamicin-susceptible strains by the checkerboard technique and with 7 of 14 gentamicin-resistant strains by the killing curve technique. Synergy between moxalactam and gentamicin against gentamicin-resistant strains of P. aeruginosa is unpredictable and strain- and method-dependent.

Anti-Bacterial Agents↗
PubMed1983

Bactericidal activities of new beta-lactam antibiotics against Bacteroides fragilis.

The bactericidal activities of cefoxitin, cefoperazone, cefotaxime, moxalactam, mezlocillin, and piperacillin were determined in duplicate against low and high inocula of each of 10 Bacteroides fragilis strains. Antibiotic concentrations resulting in 99.9% killing were established by quantitation of the inocula just before anaerobic incubation of tests and by subcultures of volumes sufficient to accurately determine less than or equal to 0.1% survivors. Inoculum effects on inhibitory and bactericidal activities were least for cefoxitin and greatest for cefoperazone and cefotaxime. Bactericidal-to-inhibitory concentration ratios of greater than or equal to 8 occurred most frequently with mezlocillin and piperacillin, regardless of inoculum size; however, 55% of the strains tested at the low inoculum size and 38% of those tested at the high inoculum size against the six antibiotics had bactericidal-to-inhibitory concentration ratios of greater than or equal to 4.

Anti-Bacterial Agents↗
PubMed1981

Bactericidal activity of cefoperazone with CP-45,899 against large inocula of beta-lactamase-producing Haemophilus influenzae.

Bactericidal activity of cefoperazone, alone and in combination with the beta-lactamase inhibitor CP-45,899, was tested against inocula of 10(7) colony-forming units of beta-lactamase-producing isolates of Haemophilus influenzae type b per ml. Of 19 strains tested, 10 required greater than or equal to 64 microgram of cefoperazone per ml for killing, whereas no strains were killed by less than 64 microgram of CP-45,899 per ml. Synergy occurred with the combination of 4 microgram of each agent per ml against 9 of the 10 cefoperazone-resistant strains.

Anti-Bacterial Agents↗
PubMed1979

Interpretation of the disk diffusion susceptibility test for amikacin: report of a collaborative study.

Because excessively high rates of false resistance have been encountered with the 10-mug amikacin disk in diffusion susceptibility tests, a study was performed to examine existing zone diameter interpretative criteria and to compare the accuracy of 10- and 30-mug amikacin disks by the error rate-bounded classification scheme. Although current zone diameter interpretative criteria eliminate false susceptibles, there is an unacceptably high rate of false resistants. This problem can be resolved in most instances by revising the zone diameter interpretative criteria for the 10-mug disk (resistant, </=9 mm; indeterminate, 10 to 11 mm; susceptible, >/=12 mm) or, preferably, by replacing the 10-mug disk with a 30-mug disk and adopting new interpretative criteria (resistant, </=14 mm; indeterminate, 15 to 16 mm; susceptible, >/=17 mm). Because of significant differences in performance among media, it is necessary to include Pseudomonas aeruginosa ATCC 27853 among controls routinely tested and to exclude from use lots of Mueller-Hinton agar yielding results outside the 75% tolerance (90% confidence) limits for amikacin.

Amikacin↗
PubMed1978

In vitro evaluation of a semisynthetic derivative of gentamicin B (Sch 21420).

The activities of Sch 21420 and amikacin were compared in vitro against 448 clinical bacterial isolates and against 82 gentamicin-resistant isolates of gram-negative bacilli. At 1 mug/ml, Sch 21420 was more active than amikacin against most Enterobacteriaceae but less active against Pseudomonas aeruginosa. Activity of these antibiotics against gentamicin-resistant organisms varied according to the species examined.

Amikacin↗
PubMed1977

Antimicrobial susceptibility of gentamicin-resistant Pseudomonas aeruginosa.

The susceptibility of 41 strains of gentamicin-resistant Pseudomonas aeruginosa to tobramycin, sisomicin, netilmicin, amikacin, and carbenicillin was determined. Amikacin and carbenicillin exhibited the greatest activity against these strains and especially against those with a high level of resistance to gentamicin. Netilmicin exhibited little activity, whereas tobramycin and sisomicin were active against approximately two-thirds of the strains. Cross-resistance to tobramycin, sisomicin, and netilmicin was frequent.

Amikacin↗
PubMed1975

Counterimmunoelectrophoresis of pneumococcal antigens:improved sensitivity for the detection of types VII and XIV.

Rapid identification of Streptococcus pneumoniae has been reported using counterimmunoelectrophoresis for the detection of specific capsular antigens in serum, cerebrospinal fluid, and urine. Previous clinical studies have failed to detect type VII or XIV pneumococcal antigen. These two types, however, account for a significant portion of pneumococcal disease. The incorporation of a sulfonated derivative of phenylboronic acid in the buffer system provides a method for the sensitive detection of these types in artificial mixtures without greatly reducing the sensitivity for the detection of other pneumococcal types. A problem with false positives encountered using human serum and barbitalbuffer was reduced by the use of buffer containing sulfonated phenylboronic acid.

Barbital↗
PubMed1974

Comparison of in vitro antibacterial activities of gentamicin and verdamicin.

The in vitro activities of verdamicin and gentamicin were studied in parallel against 1,049 bacterial isolates. Verdamicin demonstrated activity similar to that of gentamicin against members of the family Enterobacteriaceae and against Pseudomonas aeruginosa at 2 and 8 mug/ml, respectively. Proteus rettgeri and Providencia stuartii were notably more susceptible to verdamicin. The new aminoglycoside was also highly active against staphylococci but was not effective against group D streptococci.

Anti-Bacterial Agents↗