Search PubMed⌕ Search

Biomedical subjects

W L Drew

Publications and source records attributed to W L Drew.

102 records · Page 6Linked to original sources
PubMed1974

Potential unreliability of nitrofurantoin disks in susceptibility testing.

The Kirby-Bauer disk diffusion antimicrobial susceptibility test was studied with three lots of commercial nitrofurantoin disks by using 50 strains of Proteus mirabilis. One lot of disks consistently gave zone diameters 3 to 6 mm larger than the other two and resulted in a substantial number of Proteus mirabilis strains being erroneously categorized as sensitive. Antimicrobial content in disks of the three lots did not account for these differences. The pH of eluate from the unreliable disks was higher than from disks of the other two and resulted in more rapid diffusion of the antimicrobial and consequently larger zones of inhibition.

Anti-Infective Agents, Urinary↗
PubMed1972

Automated slide staining machine.

A machine is described which can perform the Gram stain. Comparison of slides stained by machine versus hand revealed no difference in reproducibility or accuracy. In addition to providing clean, dry, uniformly stained slides, the machine saves 24 sec per slide when compared with a hand staining technique.

Acetone↗
PubMed1972

Reliability of the Kirby-Bauer disc diffusion method for detecting methicillin-resistant strains of Staphylococcus aureus.

The resistance of Staphylococcus aureus to methicillin and related drugs can be reliably determined by using the Kirby-Bauer method of susceptibility testing if the incubation temperature is 35 C or below, but resistance may be missed at 37 C. The 1-mug discs of oxacillin and nafcillin or the 5-mug discs of methicillin may be used for this purpose but not the 1-mug discs of cloxacillin. The latter fail to discriminate between sensitive and resistant staphylococci by zone measurement; some resistant strains of staphylococci may show larger zones of inhibition than sensitive strains. Stability of these antibiotic-containing discs was studied under conditions of temperature and humidity variation that might be encountered in a clinical laboratory refrigerator. Oxacillin discs were the most stable and are to be preferred for susceptibility testing. Nafcillin discs were less stable, and methicillin discs lose their potency rapidly unless carefully stored in a refrigerator with a desiccant.

Cloxacillin↗
PubMedDate not supplied

Diagnosis of cytomegalovirus infection.

Diagnostic procedures for documenting cytomegalovirus (CMV) infection include culture, cytology, serology, and the detection of CMV antigens and/or nucleic acids within infected tissues. Each procedure is useful, but each has specific pitfalls. A positive urine, blood, or genital culture confirms CMV infection but does not prove that CMV is causing a specific clinical syndrome, since excretion of virus may continue for months to years following primary infection and may reoccur when a patient is immunocompromised. Seroconversion from negative to positive for specific IgG antibody is usually diagnostic of primary infection but does not provide a rapid diagnosis. CMV-specific IgM antibody is associated with primary CMV infection in nonimmunocompromised patients but may be present in immunocompromised (e.g., AIDS) patients who are infected by but do not have disease due to CMV. Conversely, tests for IgM may be negative in immunocompromised patients or neonates who are actively infected and may be falsely positive in infants who are not congenitally infected. Lastly, detection of CMV antigen in tissue by monoclonal antibodies or of CMV nucleic acids by genetic probes helps confirm tissue infection. Demonstration of CMV inclusions by cytologic or histologic examination is diagnostic of infection, but this method is not sensitive.

Antibodies, Viral↗
PubMedDate not supplied

Controversies in viral diagnosis.

A number of fallacies concerning viral diagnosis persist. It is said that viral studies are useless since there is no treatment for viral diseases, but suitable therapies are available for a number of severe viral infections. Viral culture results are thought to be too slow to affect patient management, but the average time for detection of a virus is three to four days, and greater than 70% can be reported within five days; detection of viral antigen can be provided in hours. It is thought that viral infections are best diagnosed by serologic tests. However, serologic tests requiring demonstration of a rise in titer or seroconversion are inherently slower than cultures and therefore less useful. Genetic probes are insensitive compared with cultures, and enzyme-linked immunosorbent assay methods for detecting viral antigen are no more sensitive than fluorescent antibody techniques and do not provide a means of assaying the quality of the sample. Finally, it is often stated that viral studies should be performed only in reference or regional laboratories. Regional virus laboratories should be located in teaching hospitals, and networks should be established to permit hospital laboratories to be involved at different levels.

Antigens, Viral↗
PubMedDate not supplied

Evaluation of the virus permeability of a new condom for women.

The authors tested a polyurethane women's condom for permeability to the human immunodeficiency virus (HIV) and cytomegalovirus (CMV) using an artificial intercourse model. They did not detect viral leakage in three trials for each virus. Use of this device, which can be controlled by the woman, may reduce HIV and CMV infection.

Contraceptive Devices, Female↗
PubMedDate not supplied

Severe opportunistic infections in AIDS patients with late-stage disease.

BACKGROUND: Clinicians caring for patients who have acquired immunodeficiency syndrome (AIDS) need to be aware of the wide variety of infectious diseases that can occur. Although Pneumocystis carinii pneumonia (PCP) is the most common AIDS-defining infection, other opportunistic infections associated with advanced immunodeficiency can develop after an initial diagnosis. METHODS: To ascertain AIDS-defining opportunistic infections that developed at the time of or after an AIDS diagnosis, and intensive chart review was conducted for 45 homosexual men with AIDS who died from 1990 through 1992. Time to death after first occurrence of these infections was also determined. RESULTS: The most common opportunistic infection occurring as the initial AIDS-defining illness was PCP (31 percent). The most common opportunistic infection occurring as a secondary disease was cytomegalovirus (CMV) disease (40 percent), followed by disseminated Mycobacterium avium complex (33 percent) and invasive candidiasis (31 percent). Each of these latter infections was associated with a poor prognosis (median time to death < or = 8 months). CONCLUSIONS: Diseases caused by CMV, disseminated M. avium complex, and invasive candidiasis were uncommon presenting manifestations of AIDS but were common secondary diseases that tended to be associated with limited survival. With increasing survival and a declining incidence of PCP as a result of medical therapy, other severe opportunistic infections might become increasingly recognized.

AIDS-Related Opportunistic Infections↗