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Biomedical subjects

V L Yu

Publications and source records attributed to V L Yu.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1991

Legionella infection.

As specialized laboratory tests became more widely available, Legionella species were found to be common causes of nosocomial and community-acquired pneumonia. Patients with chronic lung disease and organ transplants are at greatest risk. Clinical manifestations are non-specific, although fever greater than 39 degrees C and diarrhea are common. Erythromycin remains the antibiotic of choice, although many alternative agents are available. Once cases are discovered, a search for the organism in water distribution systems and respiratory equipment can be fruitful. Disinfection of water distribution systems by superheating and flushing or by hyperchlorination is feasible.

Erythromycin↗
PubMed1991

Legionellosis.

Legionella is a common cause of community- and hospital-acquired pneumonia. New information on the pathogenesis of infection and the host immune response is reviewed. Specialized laboratory tests, especially culture, are necessary for diagnosis since the clinical presentation is nonspecific. New antimicrobial agents and innovative approaches to disinfection of water distribution systems are presented.

Disinfection↗
PubMed1991

Pseudomonas aeruginosa bacteremia in patients undergoing liver transplantation: an emerging problem.

In our institution, Pseudomonas aeruginosa bacteremia appeared to occur with increasing frequency in patients undergoing liver transplantation. We thus conducted a prospective study to define risk factors and outcome in these patients. Over a 19-month period 6% of liver transplants were followed by Pseudomonas bacteremia. The mean age was 46 years (range, 24 to 67 years). The interval between transplantation and onset of bacteremia was 3 to 372 days (mean, 80). The incidence of Pseudomonas bacteremia in liver transplants was three times that of other transplants (heart, lung, kidney). Ninety one percent of infections were nosocomial. Polymicrobial bacteremia occurred in 30% of episodes. The portal of entry was respiratory in 30%, abdominal in 35%, and biliary in 13%. Four patients had recurrent Pseudomonas bacteremia: liver abscess (1), biliary obstruction (2), subhepatic abscess (1). Survival at 14 days was 70%. Survival rates were significantly lower for patients with hypotension, on mechanical ventilators, and increasing severity of illness (p less than 0.05). Survival was higher when bacteremia occurred within the first 30 days after transplantation compared to after 30 days. A large number (43.4%) of Pseudomonas bacteremias occurred after transplant surgery of biliary tract manipulation, while the patient was receiving a prophylactic regimen of cefotaxime and ampicillin. P. aeruginosa is an important pathogen in the liver transplant recipient; prevention may be possible for a subgroup of patients with the use of prophylactic antibiotics with activity against P. aeruginosa.

Adult↗
PubMed1990

Hepatitis B and hepatitis B vaccine requirements in schools of nursing in the United States: a national survey.

To ascertain use of the hepatitis B vaccine and occurrence of hepatitis B infection in nursing students, 1152 U.S. nursing schools were surveyed; 54.3% responded. The vaccine was required by 4.2% and recommended by 7.7%. Baccalaureate programs tended to require the vaccine more than the associate degree or diploma programs (p = 0.062). The occurrence of exposure of nursing students to blood and body fluids in the past 5 years was reported by 89.7%. Students in the diploma program had significantly more exposures (98.6%) than those in the associate degree (92.8%) and baccalaureate programs (82.7%; p less than 0.0005). At least one case of hepatitis B in the past 5 years was reported by 6.8%. Development of positive serologic markers in students after exposure to blood was reported by 7.1%. Seropositivity tended to occur in the Southeast and West (p = 0.035) and in cities with a relatively higher incidence of acquired immunodeficiency syndrome (p = 0.075). Diploma programs were significantly more likely to institute appropriate follow-up for students after exposure to blood of patients who were known or unknown carriers of hepatitis B virus (p less than 0.0001). For students exposed to blood of patients whose hepatitis B status was unknown and patients who were known hepatitis B carriers, 19.2% and 8.9%, respectively, reported they performed no follow-up whatsoever. U.S. nursing students are inadequately protected against hepatitis B. Nursing school administrators and faculty should be educated on the risks of hepatitis B infection and the indications and use of the hepatitis B vaccine.

Body Fluids↗
PubMed1990

Disinfection of water distribution systems for legionella: a review of application procedures and methodologies.

Hospital-acquired legionella pneumonia is emerging as a major problem; potable water distribution systems have been shown to be the primary reservoirs for the legionella organisms. As a result, disinfection measures have been developed to eradicate the organism from the hospital water supply. Each disinfection modality differs in its design and application such that choosing an appropriate cost-effective control measure requires careful analysis and planning. We assess in comparative fashion the disinfection modalities of thermal eradication ("heat-and-flush"), instantaneous steam-heating system, chlorination, ultraviolet light irradiation, ozonation and metal ionization. The theoretical bases, the actual procedure or system, the logistics of implementation, the costs and personnel requirements and the advantages and disadvantages are presented for each modality. Criteria for selection of a method, the use of combinations of methods, parameters for installation, pitfalls in implementation and a plan for subsequent environmental surveillance are discussed in detail.

Cross Infection↗
PubMed1990

New and emerging etiologies for community-acquired pneumonia with implications for therapy. A prospective multicenter study of 359 cases.

Three hundred fifty-nine consecutive patients with community-acquired pneumonia admitted to university, community, and VA hospitals underwent a standardized evaluation, including specialized tests for Legionella spp. and Chlamydia pneumoniae (TWAR). The most common underlying illnesses were immunosuppression (36.3%), chronic obstructive pulmonary disease (32.4%), and malignancy (28.4%). The most frequent etiologic agents were Streptococcus pneumoniae (15.3%) and Hemophilus influenzae (10.9%). Surprisingly, Legionella spp. and C. pneumoniae were the third and fourth most frequent etiologies at 6.7% and 6.1%, respectively. Aerobic gram-negative pneumonias were relatively uncommon causes of pneumonia despite the fact that empiric broad-spectrum combination antibiotic therapy is so often directed at this subgroup. In 32.9%, the etiology was undetermined. Antibiotic administration before admission was significantly associated with undetermined etiology (p = 0.0003). There were no distinctive clinical features found to be diagnostic for any etiologic agent, although high fever occurred more frequently in Legionnaires' disease. Clinical manifestations for C. pneumoniae were generally mild, although 38% of patients had mental status changes. Mortality was highest for Staphylococcus aureus (50%) and lowest for C. pneumoniae (4.5%) and Mycoplasma pneumoniae (0%). We document that specialized laboratory testing for C. pneumoniae and Legionella spp. should be more widely used rather than reserved for cases not responding to standard therapy. Furthermore, realization that C. pneumoniae and Legionella spp. are common etiologies for community-acquired pneumonia should affect empiric antibiotic prescription.

Adolescent↗
PubMed1990

Failure of a diagnostic monoclonal immunofluorescent reagent to detect Legionella pneumophila in environmental samples.

Three commercial diagnostic fluorescein-labeled antibodies, one monoclonal and two polyclonal, were compared to evaluate their abilities to detect Legionella pneumophila in environmental samples. The monoclonal conjugate failed to detect L. pneumophila in the 12 environmental samples studied by direct immunofluorescence. In contrast, the two polyclonal conjugates detected L. pneumophila in all 12 samples by both direct and indirect immunofluorescence. However, isolates recovered by culture from the 12 samples demonstrated equal immunofluorescence with all three conjugates. The reason for the failure of the monoclonal antibody to detect L. pneumophila in the environmental samples remains unknown. Laboratories considering the use of the monoclonal conjugate to screen environmental samples for L. pneumophila should be aware of this finding.

Antibodies, Bacterial↗
PubMed1990

Oerskovia xanthineolytica implicated in peritonitis associated with peritoneal dialysis: case report and review of Oerskovia infections in humans.

Oerskovia species are nocardialike bacteria that have been implicated as pathogens only rarely. These organisms are branched, gram-positive bacilli that are oxidase negative, catalase positive, and non-acid fast. Unlike Nocardia species, these organisms are motile, do not produce aerial mycelia, and possess a cell wall with large amounts of galactose. Colonies are bright yellow and produce branched vegetative hyphae on nutrient agar. A 70-year-old patient undergoing chronic ambulatory peritoneal dialysis for end-stage renal dysfunction developed recurrent peritonitis. Five peritoneal fluid cultures and one catheter specimen obtained over a period of two weeks yielded a gram-positive bacillus; Oerskovia xanthineolytica was isolated from all six cultures. Prolonged systemic therapy with gentamicin and vancomycin was unsuccessful in curing the peritonitis, but the infection resolved following removal of the peritoneal catheter. This is the first reported case of peritonitis associated with this microorganism. A review of previously described Oerskovia infections, most of which were associated with foreign bodies, showed that removal of infected foci was usually necessary for cure.

Actinomycetales↗