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Biomedical subjects

V L Yu

Publications and source records attributed to V L Yu.

At least 19 recordsLinked to original sources
PubMed1992

Postoperative wound infection. A poor prognostic sign for patients with head and neck cancer.

BACKGROUND: The development of a wound infection has been identified as a favorable prognostic factor after oncologic surgical procedures. METHODS: The authors retrospectively studied the relationship between postoperative wound infection, local/regional tumor recurrence, and survival rates in 134 patients undergoing therapeutic surgical resection for squamous cell carcinoma of the head and neck (SCCHN). RESULTS: The median age was 61 years (range, 25-87 years) with most (75%) patients having advanced disease (Stage III or IV). Patients without evidence of recurrent disease were followed up for a median time of 34 months (range, 24-68 months). Twenty-nine (22%) had local or regional bacterial infections develop postoperatively. Recurrence rates were increased (P = 0.008) in patients with postoperative wound infections compared with patients who had distant infections, e.g., pneumonia or urinary tract infection, or no infection. Disease-free survival also was adversely affected (P = 0.04) in this group. Both advanced tumor stage and postoperative wound infections were independently associated with decreased survival, with odds ratios of 2:3 and 2:4, respectively. CONCLUSIONS: These data contrast with other reports in the literature of a beneficial effect of postoperative wound infection on outcome. These findings suggest a possible relationship between local/regional immune function and postoperative infection in patients with SCCHN:

Adult↗
PubMed1992

Potable water as a cause of sporadic cases of community-acquired legionnaires' disease.

BACKGROUND: The environmental sources of sporadic, community-acquired legionnaires' disease are largely unknown, and culturing of water sources after identification of a case is currently not recommended. We conducted a prospective study of sporadic cases of community-acquired legionnaires' disease to determine whether the environmental reservoirs could be identified. METHODS: We cultured samples of potable water obtained from sources to which each of 20 patients with culture-confirmed, community-acquired legionnaires' disease had been exposed during the two weeks before the onset of symptoms. Monoclonal-antibody subtyping and restriction-endonuclease analysis were performed on the legionella isolates recovered from both the patients and the associated environmental cultures. RESULTS: For 8 of the 20 patients, isolates of Legionella pneumophila with identical subtypes were identified in cultures from both the patient and the potable water to which the patient had been exposed. The environmental reservoirs linked to the infections were the water supplies of two private residences, two nursing homes, two hospital outpatient clinics, and an industrial plant. CONCLUSIONS: Potable-water supplies that harbor L. pneumophila are an important source of community-acquired legionnaires' disease. Future studies should include attempts to identify the environmental sources of this infection.

Adult↗
PubMed1992

Erythromycin ototoxicity: prospective assessment with serum concentrations and audiograms in a study of patients with pneumonia.

BACKGROUND AND METHODS: The incidence and risk factors for erythromycin-induced ototoxicity are unknown. We conducted a prospective, nested case-control study of assessment of auditory function in patients receiving erythromycin versus other antibiotics (control group) for community-acquired pneumonia. Sequential audiograms were performed during antibiotic therapy for both cases and controls by an audiologist unaware of the identity of the therapy administered. Erythromycin serum concentrations were obtained for all patients receiving erythromycin. RESULTS: Symptomatic ototoxicity (tinnitus or hearing loss) confirmed by audiograms was documented in five of 30 patients receiving erythromycin and none of 15 receiving other antibiotics. Ototoxicity was significantly related to high peak concentration and high AUC 0-infinity as a function of decreased total systemic clearance. Ototoxicity occurred only in those patients who received 4 g/day versus 2 g/day or no erythromycin (p = 0.05). Ototoxicity resolved in all patients within 6 to 14 days after discontinuation of therapy. CONCLUSIONS: Erythromycin ototoxicity is dose- and serum concentration-dependent. Patients receiving erythromycin, especially at a total daily dose of 4 g, should be monitored regularly for subjective evidence of sensorineural hearing dysfunction. Ototoxicity is reversible if the diagnosis is made early in the course.

Adult↗
PubMed1992

Bacteremia in transplant recipients: a prospective study of demographics, etiologic agents, risk factors, and outcomes.

BACKGROUND: Bacteremic infections are a major cause of death among organ transplant recipients. We sought to identify the risk factors associated with death and examine the timing of the bacteremic episode after operation to recognize patients who may benefit from perioperative prophylactic antibiotic therapy. METHODS: A total of 125 episodes of bacteremia or fungemia in 16 heart, 26 kidney, and 70 liver recipients were monitored prospectively in 1 year. RESULTS: The urinary tract was the most frequent portal for kidney recipients, the gastrointestinal and biliary tracts were frequent for liver recipients, and the lung was frequent in heart recipients. Heart and liver recipients were more severely ill at the time of bacteremia and had bacteremia sooner after operation. Death at 14 days after onset of bacteremia was 33% in heart recipients, 24% in liver recipients, and 11% in kidney recipients. Risk of death was associated with the severity of the underlying condition of the transplant recipient, the source of the bacteremia, and the microbial agent. Pseudomonas aeruginosa and Enterobacter species had fatality rates of 47% and 63%, respectively. P. aeruginosa and Enterobacter were also most commonly associated with failures of perioperative antibiotic prophylaxis. CONCLUSIONS: There are distinct clinical patterns of bacteremia in transplant recipients. The emergence of P. aeruginosa and Enterobacter species in the immediate postoperative period appeared to be a significant cause of morbidity and death among transplant recipients.

Anti-Bacterial Agents↗
PubMed1992

Successful treatment of pulmonary infection due to Mycobacterium chelonae: case report and review.

During the past decade, Mycobacterium chelonae has been recognized with increasing frequency as a pulmonary pathogen. A review of previously reported cases reveals that most patients with pulmonary infections due to M. chelonae are nonimmunosuppressed but have underlying chronic lung disease. The infection is notably absent among blacks. M. chelonae organisms are characterized by a high degree of in vitro resistance to antituberculous drugs, and attempts at eradicating the organism through chemotherapy have been largely unsuccessful. The case of a 63-year-old previously healthy woman with progressive bilateral pulmonary disease due to M. chelonae is reported; she was treated successfully with a combination of cefoxitin and orally administered ciprofloxacin. Our experience supports the use of quinolones in combination with other active agents for the treatment of pulmonary infection due to M. chelonae.

Amikacin↗
PubMed1992

Osteomyelitis due to Veillonella parvula: case report and review.

Anaerobic gram-negative cocci of the genus Veillonella are generally normal flora of the oropharynx and upper respiratory tract. When isolated in clinical specimens, these bacteria are usually regarded as commensal organisms rather than as pathogens. We report a case of spinal osteomyelitis in which Veillonella parvula was isolated in pure culture from bone as well as blood. Osteomyelitis of the spine due to anaerobic bacteria may occur more frequently than has been recognized, and anaerobic cultures of biopsy specimens should be routinely performed.

Bacteremia↗
PubMed1992

Addition of rifampin to combination antibiotic therapy for Pseudomonas aeruginosa bacteremia: prospective trial using the Zelen protocol.

A multicenter, prospective randomized trial was conducted to determine if the addition of rifampin to a combination therapy of an antipseudomonal beta-lactam agent and aminoglycoside improves the outcome of patients with Pseudomonas aeruginosa bacteremia. The Zelen protocol for randomized-consent design was used. Consent was sought only from patients randomized to the experimental therapy (rifampin+). If the experimental therapy was refused, the patient would then receive the standard combination therapy (control); however, when outcome was evaluated, all patients randomized to the rifampin+ group, including those that declined rifampin, were compared with the control group. One hundred twenty-one consecutive hospitalized patients with positive blood cultures for P. aeruginosa were enrolled. Entry was stratified for prior use of empiric antipseudomonal antibiotics, neutropenia, severity of illness, and presence of pneumonia. Fifty-eight patients were randomized to receive rifampin (600 mg orally every 8 h for the first 72 h and then every 12 h for a total of 10 days) plus a beta-lactam agent plus an aminoglycoside. Sixty-three received the standard therapy of a beta-lactam plus an aminoglycoside agent (control). Bacteriologic cure occurred significantly more frequently in patients randomized to the rifampin+ regimen. Breakthrough or relapsing bacteremias occurred in 2% of the three-drug (rifampin+) group, compared with 14% for the two-drug (standard therapy) group. Despite this favorable trend in bacteriological response, no significant differences in survival were seen for the two treatment groups. Rifamycin derivatives warrant further clinical study as antipseudomonal agents. The Zelen protocol appears well suited for comparative trials of antimicrobial agents.

Aged↗
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↗