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Biomedical subjects

V L Yu

Publications and source records attributed to V L Yu.

At least 109 records · Page 6Linked to original sources
PubMed1994

Epidemiologic perspectives on Enterobacter for the infection control professional.

Enterobacter species have emerged as important nosocomial pathogens. Common reservoirs for these organisms include wounds and the gastrointestinal, urinary, and respiratory tracts. Enterobacter bacteremia typically occurs in patients with long-standing underlying illnesses who received antimicrobial agents before their bacteremia. The wide use of broad-spectrum antibiotics has contributed to the increased prominence of Enterobacter infections. Enterobacter species have a propensity to emerge resistant to the antibiotic therapy administered. Plasmid analysis, restriction endonuclease analysis of total cellular DNA, pulsed-field electrophoresis, and ribotyping can be valuable in investigating the spread of antibiotic-resistant strains.

Anti-Bacterial Agents↗
PubMed1994

Improved detection of spontaneous bacterial peritonitis with Bactec as compared with conventional culture methods. A prospective study.

Bacteriologic diagnosis of spontaneous bacterial peritonitis is difficult due to the low yield of isolating the bacteria from the ascitic fluid. We prospectively compared the conventional culture method with the nonradiometric Bactec culture system for the detection of bacteria in 20 episodes of spontaneous bacterial peritonitis. The ascitic fluid culture was positive by the conventional culture method in 25% and by Bactec in 79% of the episodes of spontaneous bacterial peritonitis (P = 0.004). Of culture-positive episodes, Gram-negative bacteria were detected by conventional cultures in 20% and by Bactec in 47%. Bactec culture system was significantly better than the conventional cultures for the detection of streptococci (viridans streptococci and Enterococcus fecalis), 33% versus 0 (P < 0.05). Conventional cultures did not detect bacteria that were not also detected by Bactec cultures. In conclusion, the Bactec nonradiometric culture method is superior to conventional cultures for the diagnosis of spontaneous bacterial peritonitis.

Ascitic Fluid↗
PubMed1994

Intraocular candidiasis in patients with candidemia. Clinical implications derived from a prospective multicenter study.

PURPOSE: Intraocular infection caused by Candida species can have devastating visual consequences. With the emergence of Candida as a major nosocomial pathogen, the authors investigated the prevalence of ocular lesions in patients with candidemia and evaluated risk factors for eye involvement. METHODS: This study is a prospective, multicentered, observational design. One hundred eighteen patients with candidemia were evaluated by the infectious disease service and received indirect ophthalmologic examination within 72 hours of a reported positive blood culture. Ocular findings were classified on the basis of objective, pre-determined criteria. Candida chorioretinitis was defined as the presence of focal, white, infiltrative chorioretinal lesions without vitreal involvement. Candida endophthalmitis was defined as chorioretinitis with extension into the vitreous or intravitreal "fluff balls." RESULTS: In contrast to previous studies of patients with candidemia citing prevalence rates of endophthalmitis approaching 40%, no patients were shown to have endophthalmitis. Candida chorioretinitis was seen in 9% of the patients, all of whom received antifungal agents. The observation that chorioretinitis never progressed to endophthalmitis suggests that systemic antifungal agents provided adequate ocular therapy. Risk factors for Candida chorioretinitis include fungemia with Candida albicans (versus nonalbicans species), multiple positive blood cultures, visual symptoms, and immunosuppression. Twenty percent of patients had nonspecific ocular lesions not directly related to infection. CONCLUSION: Patients with candidemia who have the risk factors noted above warrant formal ophthalmologic examination.

Adolescent↗
PubMed1994

Controlled evaluation of copper-silver ionization in eradicating Legionella pneumophila from a hospital water distribution system.

A controlled evaluation was made of the efficacy of copper-silver ionization in eradicating Legionella pneumophila from a hospital water supply. Copper-silver ionization units were installed on the hot water recirculation line of one building with water fixtures positive for Legionella species. Another building with the same water supply served as a control. Legionella species persisted within the system when copper and silver concentrations were < 0.3 and < 0.03 ppm, respectively. When copper and silver concentrations were > 0.4 and > 0.04 ppm, respectively, there was a significant decrease in Legionella species colonization, but the percentage of water fixtures positive for organisms was unchanged in the control building. When the ionization unit was inactivated, water fixtures continued to be free of Legionella species for 2 additional months. Copper-silver ionization can eradicate L. pneumophila in a water distribution system. The advantages of copper-silver ionization include relatively low cost, straightforward installation, easy maintenance, nontoxic by-products and the presence of a disinfecting residual.

Copper↗
PubMed1994

Efficacy of topical amoxicillin plus clavulanate/ticarcillin plus clavulanate and clindamycin in contaminated head and neck surgery: effect of antibiotic spectra and duration of therapy.

This prospective, randomized trial was designed to determine the efficacy and mechanism of action of topical mouthwash versus parenterally administered perioperative prophylactic antibiotics in contaminated head and neck surgery. Patients were randomly assigned to 1 of 4 treatment groups: 1 day of parenteral clindamycin (standard prophylaxis), 1 day of topical clindamycin, 5 days of topical clindamycin, or 1 day of topical amoxicillin plus clavulanate/ticarcillin plus clavulanate. Patients who received the latter regimen had fewer bacteria postoperatively compared with the other 3 treatment groups. The number of gram-negative aerobic bacilli on postoperative oral cavity cultures was increased in all 3 clindamycin groups but not in the amoxicillin plus clavulanate/ticarcillin plus clavulanate group. Parenteral clindamycin appears to exert its effect by being in the neck tissues at the time of surgery; however, all 3 topical regimens were more effective at reducing the number of bacteria in the neck viscera. Topical antibiotic prophylaxis was simple, safe, effective, and well tolerated.

Amoxicillin↗
PubMed1994

Central nervous system lesions in adult liver transplant recipients: clinical review with implications for management.

Our review shows that a wide array of neurologic complications can occur after liver transplantation. Clinical correlation of the neuropathologic lesions may be difficult, as multiple lesions of variable etiologies may coexist, and significant systemic and metabolic complications may obscure the symptoms related to an underlying lesion in the central nervous system. Nevertheless, a reasoned approach to the recognition and diagnosis of these lesions is offered. In the early post-transplantation period, noninfectious lesions predominated. Of these, anoxic-ischemic changes and vascular events (hemorrhages and/or infarcts) occurred most frequently. Anoxic events occurred a mean of 10 days after transplantation and were often preceded by transient or varying degrees of hypotension. Hemorrhagic events and infarcts occurred a median of 27 and 5 days, respectively, after transplantation. It should be noted, however, that the projected onset of these events may vary somewhat, e.g., a brain infarct developed 47 days after liver transplantation in case 2. Although defects in coagulation may predispose to hemorrhagic lesions, a source for the infarct is usually not apparent. Central pontine myelinolysis is also an early-occurring lesion: most cases are seen within 10 days of transplantation. Extrapontine involvement frequently coexisted with or was present without pontine lesions. Hyponatremia or wide variations in serum sodium generally preceded the CNS lesion. Focal areas of high signal density by CT scan in the pons was highly suggestive of central pontine myelinolysis. Cyclosporine may cause white matter changes in the brain despite normal serum cyclosporine levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The efficacy of topical antibiotic prophylaxis for contaminated head and neck surgery.

This study was undertaken to determine the feasibility of using perioperative topical antibiotics in contaminated head and neck surgery and to standardize the culture methodology (both qualitative and quantitative) which could serve as bacteriologic endpoints for evaluation. Following preliminary studies to establish oral cavity indicator organisms and the impact of a single antibiotic mouthwash dose on oral microflora, 10 consecutive patients undergoing contaminated head and neck surgery were recruited into a clinical trial where clindamycin mouthwash and intraoperative irrigation containing clindamycin were used instead of traditional parenteral antibiotics. The bacteriologic efficacy of topical clindamycin was assessed by comparing the presence of four indicator microorganisms (two aerobic and two anaerobic) cultured from two oral cavity culture sites before and after antibiotic prophylaxis. The patients included in the study underwent total laryngectomy plus neck dissection(s) for laryngeal or hypopharyngeal carcinoma from 1991 to 1992 at a large university hospital specializing in head and neck cancer surgery. The main outcome measures used were the development of a postoperative wound infection and quantitative and qualitative bacteriology of the intraoperative neck wound and postoperative oral cavity. Two aerobic and two anaerobic organisms proved useful as a practical indicator for bacteriologic efficacy. Preoperative mouthwash resulted in a 99% reduction of both aerobic and anaerobic bacteria in intraoperatively cultured neck sites. Irrigation during surgery with the clindamycin solution further reduced the bacterial neck counts by an additional 90%. There was a consistent overgrowth of Hemophilus species on postoperative oral cavity cultures. No patient developed a postoperative wound infection. A topical prophylactic antibiotic alone was efficacious and safe for patients undergoing major contaminated head and neck surgery. Culture methods for assessment of bacteriologic efficacy were reproducible and cost-effective. This pilot study furnishes the ethical and scientific basis for large-scale prospective trials comparing topical versus parenteral antimicrobial agents.

Administration, Topical↗
PubMed1994

Cutaneous cryptococcosis mimicking bacterial cellulitis in a liver transplant recipient: case report and review in solid organ transplant recipients.

Cutaneous cryptococcosis is an uncommon manifestation of disseminated cryptococcal disease. We report a liver transplant recipient presenting with onset over 3 days of progressive pain and swelling of the lower extremity and foot with erythema and heat. Cryptococcal cellulitis was documented, but in retrospect the clinical presentation was indistinguishable in presentation and appearance from acute bacterial cellulitis. The patient also proved to have concomitant cryptococcal septic arthritis; the presence of cryptococcal antigen in the synovial fluid allowed a rapid and definitive diagnosis. Subsequently, cultures of skin, synovial fluid, and blood were all positive for cryptococci. Cryptococcus should be considered in the differential diagnosis of bacterial cellulitis in a liver transplant recipient not responding to antibacterial therapy.

Ankle Joint↗
PubMed1993

Prosthetic valve endocarditis resulting from nosocomial bacteremia. A prospective, multicenter study.

OBJECTIVE: To determine the incidence of endocarditis in bacteremic patients with prosthetic heart valves and the risk factors for and the effect of duration of antibiotic therapy on development of endocarditis in such patients. DESIGN: Multicenter, prospective observational study. SETTING: Six university teaching hospitals with high-volume cardiothoracic surgery. PARTICIPANTS: One hundred seventy-one consecutive patients with prosthetic heart valves who developed bacteremia during hospitalization. MEASUREMENTS AND MAIN RESULTS: Patients were evaluated when they were identified as having bacteremia and 1, 2, 6, and 12 months after its occurrence. Of 171 patients, 74 (43%) developed endocarditis: Fifty-six (33%) had prosthetic valve endocarditis at the time bacteremia was discovered ("endocarditis at outset"), whereas 18 (11%) developed endocarditis a mean of 45 days after bacteremia was discovered ("new endocarditis"). Mitral valve location and staphylococcal bacteremia (Staphylococcus aureus or S. epidermidis) were significantly associated with the development of "new" endocarditis. All 18 cases of new endocarditis were nosocomial, and in 6 of these cases (33%) bacteremia was acquired via intravascular devices. Twenty-one patients without evidence of endocarditis at the time of bacteremia received short-term antibiotic therapy (< 14 days); 1 patient (5%) developed endocarditis. Eleven of 70 patients (16%) who received long-term antibiotic therapy (> 14 days) developed endocarditis (P > 0.2). CONCLUSIONS: Bacteremic patients with prosthetic heart valves were at notable risk for developing endocarditis, even when they received antibiotic therapy before endocarditis developed and regardless of the duration of such therapy. Intravascular devices were a common portal of entry.

Adult↗
PubMed1993

Is pneumonia really the old man's friend? Two-year prognosis after community-acquired pneumonia.

Is pneumonia "the old man's friend"--a terminal event for patients who will otherwise die soon of underlying chronic disease? If so, chronological age might influence treatment policy. We investigated the predictors of 2-year mortality after patients' admission to hospital for community-acquired pneumonia, and focused on the predictive value of age. In a prospective cohort study 141 consecutive patients were admitted to hospital with community-acquired pneumonia. Clinical, laboratory, and sociodemographic data were collected on admission. Comorbidity was categorised as mild, moderate, or severe by a physician based on the patient's medical history. Survival was assessed at 24 months after discharge. 22 (16%) patients died in hospital. Of the remaining 119, 38 (32%) died over the next 24 months. In a Cox model, 2-year mortality was independently related to severe comorbidity (relative risk [RR] = 9.4) or moderate comorbidity (RR = 3.1), and to haematocrit less than 35% (RR = 2.9) (all p < or = to 0.005). However, compared with patients aged 18-44 years, patients aged 45-64 (RR = 0.84), 65-74 (RR = 1.28), and 75-92 (RR = 1.99) were not significantly more likely to die during the 24 months after discharge (all p > or = to 0.2). Old age should not be a sole criterion for withholding aggressive treatment of community-acquired pneumonia.

Adolescent↗
PubMed1993

Simultaneous presentation of malignant external otitis and temporal bone cancer.

Malignant external otitis and squamous cell carcinoma of the external auditory meatus are both characteristically seen in the older population. While some of the signs and symptoms of these two diseases are similar (otalgia, otorrhea, bone destruction on computed tomographic scan), they have rarely been reported in the same patient. We present an unusual case of temporal bone cancer and malignant external otitis presenting concurrently in an elderly, nondiabetic host. Precipitating factors and diagnostic criteria are discussed. This case illustrates the importance of an adequate biopsy specimen in all patients presenting with presumed "classic" malignant external otitis. Consideration must also be given for the existence of malignant external otitis in the presence of carcinoma. Finally, evolution of malignant external otitis in this patient following aural irrigation supports previous suggestions that this disease may be induced iatrogenically.

Aged↗
PubMed1993

Beta-Lactam antibiotic-induced leukopenia in severe hepatic dysfunction: risk factors and implications for dosing in patients with liver disease.

PURPOSE: To determine if an association could be established for leukopenia and administration of beta-lactam antibiotic therapy in patients with hepatic dysfunction. If such an association could be found, to determine the incidence, timing, and risk factors for beta-lactam antibiotic-induced leukopenia. PATIENTS AND METHODS: Patients with hepatic dysfunction, i.e., liver transplant recipients as well as patients with end-stage liver disease awaiting liver transplantation, seen at our institution between October 1989 and October 1991, who received 7 or more days of antibiotics, were studied in a prospective observational fashion. Complete blood count was determined at baseline and followed until the completion of the antibiotic course or until the resolution of leukopenia in leukopenic patients. RESULTS: Leukopenia occurred after a mean of 6 days with 23% of the beta-lactam antibiotic courses as compared with 0% with the non-beta-lactam antibiotic courses (p = 0.046). Development of leukopenia correlated with the severity of liver disease. Patients developing leukopenia had worse synthetic hepatic function as evidenced by a lower serum albumin level (p < 0.01), a lower serum cholesterol level (p < 0.05), and a higher prothrombin time (p < 0.01) as compared with the patients without leukopenia. Leukopenic patients had a lower baseline white blood cell count (p < 0.051) and a lower baseline platelet count (p < 0.01) indicative of a greater degree of hypersplenism. Leukopenic patients received a higher mean daily dosage of cephalosporins as compared with nonleukopenic patients. CONCLUSION: beta-Lactam antibiotics when administered in usually recommended dosages can induce leukopenia in patients with hepatic dysfunction. The probable mechanism is impaired hepatic metabolism of the beta-lactam antibiotics resulting in bone marrow suppression of white cell precursors from excessive antibiotic concentrations. The more severe the hepatic dysfunction, the greater the risk. We propose a reduction in dosages of beta-lactam antibiotics when used in patients with hepatic dysfunction. Finally, we raise the possibility that this adverse drug effect is more common than currently recognized by physicians.

Adult↗
PubMed1993

Methicillin-resistant Staphylococcus aureus: a consensus review of the microbiology, pathogenesis, and epidemiology with implications for prevention and management.

Methicillin-resistant Staphylococcus aureus (MRSA) has become a major nosocomial pathogen in community hospitals, long-term-care facilities, and tertiary care hospitals. The basic mechanism of resistance is alteration in penicillin-binding proteins of the organism. Methods for isolation by culture and typing of the organism are reviewed. MRSA colonization precedes infection. A major reservoir is the anterior nares. MRSA is usually introduced into an institution by a colonized or infected patient or health care worker. The principal mode of transmission is via the transiently colonized hands of hospital personnel. Indications for antibiotic therapy for eradication of colonization and treatment of infection are reviewed. Infection control guidelines and discharge policy are presented in detail for acute-care hospitals, intensive care and burn units, outpatient settings, and long-term-care facilities. Recommendations for handling an outbreak, surveillance, and culturing of patients are presented based on the known epidemiology.

Anti-Bacterial Agents↗