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Victor L Yu

Publications and source records attributed to Victor L Yu.

41 records · Page 3Linked to original sources
PubMed2002

Hospital-acquired legionellosis: solutions for a preventable infection.

Hospital-acquired Legionnaires' disease has been reported from many hospitals since the first outbreak in 1976. Although cooling towers were linked to the cases of Legionnaires' disease in the years after its discovery, potable water has been the environmental source for almost all reported hospital outbreaks. Microaspiration is the major mode of transmission in hospital-acquired Legionnaires' disease; showering is not a mode of transmission. Since the clinical manifestations are non-specific, and specialised laboratory testing is required, hospital-acquired legionellosis is easily underdiagnosed. Discovery of a single case of hospital-acquired Legionnaires' disease is an important sentinel of additional undiscovered cases. Routine environmental culture of the hospital water supply for legionella has proven to be an important strategy in prevention. Documentation of legionella colonisation in the water supply would increase physician index of suspicion for Legionnaires' disease and the necessity for in-house legionella test methods would be obvious. Legionella is a common commensal of large-building water supplies. Preventive maintenance is commonly recommended; unfortunately, this measure is ineffective in minimising legionella colonisation of building water supplies. Copper-silver ionisation systems have emerged as the most successful long-term disinfection method for hospital water disinfection systems. There is a need for public-health agencies to educate the public and media that discovery of cases identifies those hospitals as providers of superior care, and that such hospitals are not negligent.

Child, Preschool↗
PubMed2002

Negative effect of high pH on biocidal efficacy of copper and silver ions in controlling Legionella pneumophila.

Copper-silver (Cu-Ag) ionization has effectively controlled Legionella spp. in the hot water systems of numerous hospitals. However, it was ineffective at controlling Legionella in one Ohio hospital despite the confirmation of adequate total concentrations of copper and silver ions. The pH of the water at this hospital was found to be 8.5 to 9.0. The purpose of this study was to investigate the impact of pH and other water quality parameters, including alkalinity (HCO3-), hardness (Ca2+ and Mg2+), and amount of dissolved organic carbon (DOC), on the control of Legionella by Cu-Ag ionization. Initial concentrations of Legionella and copper and silver ions used in batch experiments were 3 x 10(6) CFU/ml and 0.4 and 0.08 mg/liter, respectively. Changes in bicarbonate ion concentration (50, 100, and 150 mg/liter), water hardness (Ca2+ at 50 and 100 mg/liter; Mg2+ at 40 and 80 mg/liter), and level of DOC (0.5 and 2 mg/liter) had no significant impact on the efficacy of copper and silver ions in killing Legionella at a neutral pH. When the pH was elevated to 9 in these experiments, copper ions achieved only a 10-fold reduction in the number of Legionella organisms in 24 h, compared to a millionfold decrease at pH 7.0. Silver ions were able to achieve a millionfold reduction in 24 h at all ranges of water quality parameters tested. Precipitation of insoluble copper complexes was observed at a pH above 6.0. These results suggest that pH may be an important factor in the efficacy of copper-silver ionization in controlling Legionella in water systems.

Bicarbonates↗
PubMed2002

Community-acquired Klebsiella pneumoniae bacteremia: global differences in clinical patterns.

We initiated a worldwide collaborative study, including 455 episodes of bacteremia, to elucidate the clinical patterns of Klebsiella pneumoniae. Historically, community-acquired pneumonia has been consistently associated with K. pneumoniae. Only four cases of community-acquired bacteremic K. pneumoniae pneumonia were seen in the 2-year study period in the United States, Argentina, Europe, or Australia; none were in alcoholics. In contrast, 53 cases of bacteremic K. pneumoniae pneumonia were observed in South Africa and Taiwan, where an association with alcoholism persisted (p=0.007). Twenty-five cases of a distinctive syndrome consisting of K. pneumoniae bacteremia in conjunction with community-acquired liver abscess, meningitis, or endophthalmitis were observed. A distinctive form of K. pneumoniae infection, often causing liver abscess, was identified, almost exclusively in Taiwan.

Adolescent↗
PubMedDate not supplied

Diagnosis of ventilator-associated pneumonia: focus on nonbronchoscopic techniques (nonbronchoscopic bronchoalveolar lavage, including mini-BAL, blinded protected specimen brush, and blinded bronchial sampling) and endotracheal aspirates.

The ideal diagnostic approach for ventilator-associated pneumonia currently is based on invasive procedures to obtain respiratory tract cultures. Given the lack of consensus and relatively poor acceptance of full bronchoscopic bronchoalveolar lavage (BAL) and protected specimen brush (PSB), less invasive procedures have been developed. We review the nonbronchoscopic procedures (nonbronchoscopic bronchoalveolar lavage, including mini-BAL, blinded protected specimen, and blinded bronchial sampling) and endotracheal aspiration. We provide a critique of the methods used, the types of catheters inserted, and the sample collection methods. Most studies were flawed in that antibiotic use before initiation of the procedure was not controlled. The variability of both the methods and the criteria for the gold standard in the numerous investigations show that these procedures are neither standardized nor proven to be accurate and often did not improve management. Pending future studies, use of endotracheal aspirates without the use of quantitation seems to be a reasonable approach for clinicians who are not committed to an invasive procedure.

Bronchi↗