PubMed Health⌕ Search

Biomedical subjects

V L Yu

Publications and source records attributed to V L Yu.

At least 145 records · Page 8Linked to original sources
PubMed1992

Clinical demonstration of isolation of Nocardia asteroides on buffered charcoal-yeast extract media.

Nocardia asteroides was isolated only from sputum samples, obtained from three patients with pulmonary nocardiosis, that had been cultured onto buffered charcoal-yeast extract (BCYE) and selective BCYE media as part of laboratory workups for Legionella species. A decontamination procedure with low-pH pretreatment (KCl-HCl solution) had been performed on the sputa prior to culture onto the BCYE media because direct cultures on the media were overgrown with commensal microflora. Chalky white colonies, 0.5 to 1.0 mm in diameter, that were subsequently identified as N. asteroides grew well on the BCYE media. Thus, the techniques and the selective media used for Legionella species were useful for isolating Nocardia species from sputum.

Agar↗
PubMed1992

Cefamandole-susceptible strains of Legionella pneumophila serogroup 1: implications for diagnosis and utility as an epidemiological marker.

The standard selective Legionella medium that contains cefamandole failed to grow legionella pneumophila serogroup 1, subtype Bellingham, from a sputum sample from a patient with nosocomial Legionnaires' disease; the isolate did grow on a similar selective medium that substitutes vancomycin for cefamandole. Two Bellingham isolates from this patient's hospital environment also failed to grow when tested on the cefamandole medium. We tested 106 additional L. pneumophila serogroup 1 isolates that belonged to nine different monoclonal antibody subtypes and demonstrated that susceptibility to cefamandole was rare (10%) and limited to the Bellingham subtype. The diagnosis of Legionnaires' disease may be missed unless the culture protocol includes both a nonselective medium and a selective medium that does not contain cefamandole. In vitro susceptibility to cefamandole also provided an epidemiologic marker that linked a water source for a patient to nosocomial Legionnaires' disease.

Cefamandole↗
PubMed1992

The efficacy of perioperative antibiotic therapy on recovery following tonsillectomy in adults: randomized double-blind placebo-controlled trial.

One hundred and one adult patients undergoing tonsillectomy for chronic/recurrent tonsillitis completed a prospective, randomized, double-blind, placebo-controlled study in which ticarcillin disodium and clavulanate potassium (Timentin) or placebo was administered intravenously at the time of surgery and for 12 hours postoperatively. The patients than received oral amoxicillin and clavulanate potassium (Augmentin) therapy or placebo for an additional seven days. Each patient kept a daily log to assess the incidence and severity of postoperative symptoms. Tonsillar core tissue at the time of surgery, as well as tonsillar fossa cultures after 7 days of treatment, were obtained. Those patients who received antibiotics fared consistently better in the immediate postoperative period compared with the placebo group. Specifically, patients in the antibiotic group experienced significantly less mouth odor, were able to tolerate a regular diet sooner, and resumed their normal activities earlier than did patients who received placebo. Patients who received antibiotics experienced fewer days with mouth odor (p = 0.004). In addition, on postoperative days 3 to 5, the antibiotic group was eating a regular diet (p = 0.05) and had returned to their routine activities earlier (p = 0.045) when compared with the placebo group. Perioperative antibiotic therapy was well tolerated and was effective in minimizing symptoms after tonsillectomy.

Adolescent↗
PubMed1992

Legionella pneumophila in residential water supplies: environmental surveillance with clinical assessment for Legionnaires' disease.

Although cases of community-acquired Legionnaires' disease have been epidemiologically linked to residential water supplies, the risk of acquiring Legionnaires' disease from exposure to Legionella pneumophila in residential water systems is uncertain. The residential water supplies of 218 members of the American Legion in six different geographical areas in Pittsburgh were cultured for L. pneumophila. Residents of the homes provided a recent medical history and a blood sample for detection of antibodies to legionella. A urine sample for legionella urinary antigen testing was also requested from individuals residing in legionella-positive homes and individuals with a positive antibody test. Six percent (14/218) of the homes yielded L. pneumophila (range within six areas 0-22%). Lower hot water tank temperature was significantly associated with legionella positivity (P less than 0.01). Analysis of water samples for mineral content showed no association between legionella positivity and concentrations of calcium and magnesium. Water samples from the area where 22% of the homes surveyed were positive for legionella had a higher iron content than water samples from the other areas tested. None of the individuals residing in legionella-positive homes showed elevated antibody titres to legionella or the presence of legionella antigen in urine. For the immunocompetent hosts, the risk of contracting Legionnaires' disease from exposure to contaminated household water supplies in the Pittsburgh area appears to be low.

Adult↗
PubMed1991

Enterobacter bacteremia: clinical features and emergence of antibiotic resistance during therapy.

OBJECTIVES: To study the effect of previously administered antibiotics on the antibiotic susceptibility profile of Enterobacter, the factors affecting mortality, and the emergence of antibiotic resistance during therapy for Enterobacter bacteremia. DESIGN: Prospective, observational study of consecutive patients with Enterobacter bacteremia. SETTING: Three university tertiary care centers, one major university-affiliated hospital, and two university-affiliated Veterans Affairs medical centers. PATIENTS: A total of 129 adult patients were studied. MEASUREMENTS: The two main end points were emergence of resistance during antibiotic therapy and death. MAIN RESULTS: Previous administration of third-generation cephalosporins was more likely to be associated with multiresistant Enterobacter isolates in an initial, positive blood culture (22 of 32, 69%) than was administration of antibiotics that did not include a third-generation cephalosporin (14 of 71, 20%; P less than 0.001). Isolation of multiresistant Enterobacter sp. in the initial blood culture was associated with a higher mortality rate (12 of 37, 32%) than was isolation of a more sensitive Enterobacter sp. (14 of 92, 15%; P = 0.03). Emergence of resistance to third-generation cephalosporin therapy (6 of 31, 19%) occurred more often than did emergence of resistance to aminoglycoside (1 of 89, 0.01%; P = 0.001) or other beta-lactam (0 of 50; P = 0.002) therapy. CONCLUSIONS: More judicious use of third-generation cephalosporins may decrease the incidence of nosocomial multiresistant Enterobacter spp., which in turn may result in a lower mortality for Enterobacter bacteremia. When Enterobacter organisms are isolated from blood, it may be prudent to avoid third-generation cephalosporin therapy regardless of in-vitro susceptibility.

Adolescent↗
PubMed1991

Methicillin-resistant staphylococcal colonization and infection in a long-term care facility.

OBJECTIVE: To determine the natural history of colonization by methicillin-resistant Staphylococcus aureus (MRSA) among patients in a long-term care facility. We specifically sought to determine if MRSA colonization was predictive of subsequent infection. DESIGN: Cohort study. SETTING: Long-term Veterans Affairs Medical Center. PATIENTS: A total of 197 patients residing on two units were followed with regular surveillance cultures of the anterior nares. MAIN OUTCOME MEASUREMENT: The development of staphylococcal infection. RESULTS: Thirty-two patients were persistent carriers of MRSA and 44 were persistent carriers of methicillin-susceptible strains (MSSA). Twenty-five percent of MRSA carriers had an episode of staphylococcal infection compared with 4% of MSSA carriers and 4.5% of non-carriers (P less than 0.01; relative risk 3.8; 95% CI, 2.0 to 6.4). The rate of development of infection among MRSA carriers was 15% for every 100 days of carriage. Using logistic regression analysis, persistent MRSA carriage was the most significant predictor of infection (P less than 0.001; odds ratio, 3.7). Seventy-three percent of all MRSA infections occurred among MRSA carriers. Isolates of MRSA from 7 patients were typed. Colonizing and infecting strains had the same phage type in all 7 patients and the same pattern of plasmid EcoRI restriction endonuclease fragments in 5 patients. CONCLUSIONS: Colonization of the anterior nares by MRSA predicts the development of staphylococcal infection in long-term care patients; most infections arise from endogenously carried strains. Colonization by MRSA indicates a significantly greater risk for infection than does colonization by MSSA. The results offer a theoretic rationale for reduction in MRSA infections by interventions aimed at eliminating the carrier state.

Aged↗
PubMed1991

A new dosing schedule for gentamicin in blood pythons (Python curtus): a pharmacokinetic study.

Gentamicin is frequently used in the treatment of aerobic Gram-negative infections in reptiles. Pharmacokinetic data to ensure proper dosing are scant, especially for large snakes. A pharmacokinetic study of gentamicin was therefore conducted in four blood pythons. Snakes were given intramuscular injections of either 2.5 mg kg-1 or 3.0 mg kg-1 loading dose followed by 1.5 mg kg-1 at 72 and 96 hours. A linear pharmacokinetic relationship between gentamicin serum concentrations and time was demonstrated in each of the four snakes studied. Peak serum concentrations occurred six to 10 hours after injection and ranged from 4.6 to 8.9 micrograms ml-1. Half-life was variable and ranged from 32 to 110 hours. Total body clearance and apparent volume of distribution varied little between the individual snakes studied. There was no evidence of renal toxicity. For blood pythons a loading dose of 2.5 mg kg-1 followed by 1.5 mg kg-1 at 96 hour intervals is recommended. If higher concentrations are desired, a loading dose of 3.0 mg kg-1 followed by 1.5 mg kg-1 at 96 hours can be given. These dosing schedules will provide serum concentrations in excess of the minimum inhibitory concentrations for most aerobic Gram-negative bacilli that are pathogenic in snakes; gentamicin accumulation with subsequent renal dysfunction should not occur.

Animals↗
PubMed1991

Empiric antibiotic selection by physicians: evaluation of reasoning strategies.

The objectives of the study were to evaluate the appropriateness of empiric antibiotic selection by housestaff treating medical patients with bacteremia. The design was a prospective, observational study at a university-affiliated hospital. Seventy-eight patients with bacteremia were evaluated. A clinical grade of acceptable or not acceptable was assigned to each antibiotic prescription by a consensus panel. The consensus panel found that 34.6% of antibiotic prescriptions were unacceptable (clinical grade). At least one flaw in the chain of reasoning was found in 56.4% of the 78 cases evaluated. Assessment of the clinical setting was correct in 94.9% of the cases; the portal of entry was identified in 91%; adequate knowledge of the bacterial flora at the suspected site of infection was found in 69%; the diagnostic workup was appropriate in 81%, and the correct antibiotic susceptibility patterns were given in 72%. A correct chain of reasoning was more likely to result in an acceptable clinical grade than flawed reasoning (p less than 0.005). However, an appropriate antibiotic selection was made by some physicians despite flawed reasoning, and inappropriate antibiotic selection occurred in a few cases despite fautless reasoning. In 3.8% of cases, unexpected organisms appeared in blood culture. Prescription of broad spectrum antibiotics may then be learned response. If so, educational efforts that emphasize narrow, rather than broad spectrum prescribing may be inadequate to change physician prescribing habits.

Anti-Bacterial Agents↗
PubMed1991

Klebsiella pneumonia in the modern era: clinicoradiographic correlations.

A classic clinical and radiographic picture of Klebsiella pneumonia has emerged in the literature. Patients are typically male, older than 48 years, and have a history of chronic alcoholism. The majority of these pneumonias are community acquired. Bulging interlobar fissures and cavitation are radiographic findings said to be distinctive for Klebsiella pneumonia. We prospectively studied 15 cases of bacteremically proven Klebsiella pneumonia and found clinical and radiographic features strikingly different from those described in the literature. Immunosuppression (from corticosteroids, cytotoxic chemotherapy, neutropenia, hematologic malignancy, and transplantation) now rivals alcoholism as the primary risk factor. Cases tended to be nosocomial rather than community acquired. Neither bulging interlobar fissure nor cavitation was seen in any case. The right upper lobe was involved in 11 of our 15 cases. Pneumonia due to Klebsiella oxytoca was more likely to be isolated from patients with bilateral infiltrates, while Klebsiella pneumoniae was more likely in patients with unilateral infiltrates.

Alcoholism↗
PubMed1991

Invasive aspergillosis in AIDS.

Invasive pulmonary aspergillosis was diagnosed in two patients with HIV infection, one with prolonged neutropenia and another receiving corticosteroid therapy. We found 17 additional cases in the literature. A known predisposing risk factor for invasive aspergillosis, eg, neutropenia, corticosteroid use, or intravenous drug abuse, was present in 79% of the cases. That the known immunologic defect of AIDS is not a major host defense against Aspergillus is supported by the empiric observation of the relative rarity of aspergillosis in patients with AIDS. The lung was the most common site of Aspergillus infection (75%), and transbronchial biopsy is diagnostically useful. Central nervous system involvement was seen in 55% and appears to be more frequent in HIV-infected patients than in other immunosuppressed patients with invasive aspergillosis. Prognosis is grim. Despite early institution of amphotericin B therapy in a few cases, the disease was uniformly fatal. Efficacy of therapy with amphotericin B plus rifampin or itraconazole remains to be evaluated. We conclude that aspergillosis is not an AIDS-related opportunistic infection.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Cefonicid versus clindamycin prophylaxis for head and neck surgery in a randomized, double-blind trial, with pharmacokinetic implications.

Perioperative single-dose antibiotic prophylaxis of cefonicid was compared with clindamycin in a prospective, randomized, double-blind trial of patients undergoing oncologic head and neck surgery. Antibiotics were administered intravenously beginning 1 to 2 h preoperatively. Cefonicid, 1 g, was given as a single dose. Clindamycin, 600 mg, was administered every 8 h for a total of four doses. Blood and wound drainage samples were collected for 24 h following the dose of cefonicid and assayed for total and free cefonicid concentrations, using reverse-phase high-performance liquid chromatography. Although total concentrations of cefonicid in both serum and wound drainage exceeded the MIC for 90% of the isolates of common bacterial pathogens for 24 h, free concentrations in serum and wound drainage (11.0 and 14.9% of total concentrations) were subinhibitory within 6 h following administration. Free concentrations of cefonicid in the postoperative wound drainage were subinhibitory for the entire study period, both perioperatively and postoperatively. Postoperative wound infection occurred significantly (P less than 0.05) more frequently in patients receiving cefonicid (24%) as compared with those receiving clindamycin (8.2%). The relatively low free levels of cefonicid achieved in serum and wound drainage were attributed to the high degree of protein binding (89% in serum) and may be related to the poor clinical outcome.

Cefonicid↗
PubMed1991

Use of ciprofloxacin versus use of aminoglycosides for therapy of complicated urinary tract infection: prospective, randomized clinical and pharmacokinetic study.

The efficacy of oral ciprofloxacin was compared with that of parenteral aminoglycoside for therapy of complicated urinary tract infection in a prospective randomized trial. The setting was a chronic-care Veterans Administration facility in which long-term bladder catheterization and resistant bacteria were common. Sixty-five consecutive patients were stratified for presence and type of bladder catheter, the presence of Providencia and Pseudomonas aeruginosa organisms versus other urinary pathogens, and renal dysfunction. A pharmacokinetic study of ciprofloxacin concentrations in serum and urine was performed with selected patients. Urinary catheters were present in 94%. All patients were symptomatic, and 58.5% had fever. Ciprofloxacin, 500 mg every 12 h orally, was compared with parenteral aminoglycoside for 7 to 10 days. Clinical response, defined by resolution of symptoms and fever at 5 to 9 days posttherapy (short-term) and 28 to 30 days posttherapy (long-term), was essentially identical for both treatment groups. Bacteriologic response, defined by sterile urine cultures, showed that ciprofloxacin was significantly more efficacious (P = 0.0005) than aminoglycoside at 5 to 9 days posttherapy. However, by 28 to 30 days, the response rate was essentially identical. Emergence of resistance to the study antibiotic was seen in 62 and 70% of those who did not show a bacteriological response and were receiving ciprofloxacin and aminoglycosides, respectively. Concentrations of ciprofloxacin and aminoglycoside in the urine substantially exceeded the MIC for the urinary pathogens isolated, although these concentrations did not correlate with short-term bacteriologic response for either antibiotic. Ciprofloxacin was efficacious in complicated urinary tract infection compared with the current standard of parenteral aminoglycoside among catheterized patients with relatively resistant bacteria.

Administration, Oral↗