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AIDS serology testing in low, and high-risk groups
REVIEWS Material for the Review section, including books, monographs, articles, and audiovisuals, should be sent to Sego Matsumiya, R.N., Infection Control Nurse, Veterans Administration Medical Center, 500 Foothill Blvd., Salt Lake City, UT 84148. Individual reprints of articles reviewed must be obtained from the designated author.
Literature
Bladder irrigation with povidone-iodine in prevention of urinary-tract infections associated with intermittent urethral catheterisation Van Den Broek PJ, Daha TJ, Mouton RP. Lancet 1:563-565, 1985. Reprint requests: P. J. Van Den Broek, Department of Infectious Diseases and Medical Microbiology, and Infection Control Committee, Leiden University Hospital, The Netherlands.
This investigation was prompted by the observation that 6.9% of 437 patients admitted to the Department of Orthopedics in a 4-month period developed bacteriuria after intermittent catheterization. In a prospective, controlled study, the efficacy of bladder irrigation with povidone-iodine after intermittent catheterization was compared with an untreated control group. In the treated group, 50 ml povidoneiodine 2% was instilled into the bladder and allowed to drain immediately before removal of the catheter. The incidence of bacteriuria in the treated group was 4% (1 of 28) compared with an incidence of 28% (8 of 29) in the untreated group. Bacteiuria was associated with pyuria in the one patient given treatment who developed bacteriuria and in three of the eight patients with no treatment who developed bacteriuria. The results of urine cultures collected 3 days after the last catheterization in patients in both groups were not presented. The authors concluded that irrigation of the urinary bladder with 2% povidone-iodine solution at the end of an episode of urethral catheterization is an effective method to prevent bacterial contamination of the urinary tract. 194
This is an interesting study for infection control practitioners to review. Unfortunately, the numbers are so small in each group that the significance of the observations cannot be evaluated. No difference was noted between the two groups with regard to episodes of bacteriuria accompanied by pyuria. No data are presented regarding the incidence of symptomatic infection or results of cultures taken 3 days or more after the catheter was removed. If therapy with povidone-iodine were recommended for general use, the possible selection of resistant organisms, drug toxicity, and increased costs of catheter care would be causes for concern. Nonetheless, this study presents an interesting new strategy for the prevention of catheter-associated bacteriuria and should be reevaluated by a more definitive clinical trial.
AIDS serology groups
testing
in low= and high-risk
Carlson JR, Bryant ML, Hinrichs SH, et al. JAMA 253:34053408, 1985. Reprint requests: Dr. J. R. Carlson, Department of Medical Pathology, Room 3453, MSI-A, School of Medicine, University of California, Davis, CA 95616.
This study outlines the technical data needed to establish performance standards for the serologic detection of antibody to the acquired immunodeficiency syndrome (AIDS)-associated retroviruses (anti-HTLV-III). In this study, 1257 serum samples collected from both low- and high-risk population groups were tested for anti-HTLV-III by an enzyme-linked immmunosorbent assay (ELISA) method. The sensitivity
Volume
14 Number
August,
1986
4
Reviews
and specificity of the ELISA test were determined by Western blot and immunofluorescence assay (IFA) techniques. The investigators used a relatively low ratio of positive to negative (P/N) (control) reactivity to indicate a positive ELISA test (a P/N ratio of 2 or greater). With this criterion for a positive test, 91 of 1014 unselected low-risk blood donors had falsely positive results by the ELISA test, based on the lack of Western blot confirmation; two true positives were found in this low-risk group. In contrast, 106 of 108 specimens from highrish groups (asymptomatic homosexual men, patients with hemophilia, patients with AIDSrelated complex, and patients with AIDS) were positive by ELISA and confirmed by Western blot and immunofluorescence assays. Four falsenegative ELISA results were found in patients with AIDS. Ten of 69 patients with AIDS had negative results by all three serologic tests. The investigators concluded that the definition for a positive ELISA test that they used (P/N ratio greater than or equal to 2) was very sensitive for detecting antibody positivity but was not very specific. The number of false-positive results necessitates the use of a confirmation test by Western blot or IFA assay to improve the specificity of the test result.
Occupational paramedics
exposure
to hepatitis
B in
Valenzuela TD, Hook EW, Copass MK, Corey L. Arch intern Med 145:1976-1977, 1985. Reprint requests: Dr. Terence D. Valenzuela, Section of Emergency Medicine, College of Medicine, University of Arizona Health Sciences Center, Tucson, AZ 85724.
To determine their occupational risk for hepatitis B infection, 59 Seattle paramedics were tested for hepatitis B serum markers. These personnel were considered to be at risk for hepatitis B infection because they routinely performed invasive procedures such as intravenous line placements, thoracenteses, pericardiocenteses, endotracheal intubations, and control of hemorrhage. In the 12-month period before blood sampling, each paramedic was in-
195
volved in an average of 195 procedures in which there was a high likelihood of exposure to blood or body fluids. Serologic testing revealed evidence of prior hepatitis B infection in 25%, as determined by the presence of hepatitis B surface antibody or hepatitis B e antibody. This rate was five times that in a similar Seattle population. Seropositivity did not correlate with age, race, clinical history, or length of service. The investigators concluded that paramedics are at increased risk of hepatitis B infection and that hepatitis B vaccine should be strongly considered for members of this group.
Some current vaccine
issues
relating
to rubella
Preblud SR. JAMA 254:253-256,1985. Reprint requests: Technical Information Services, Center for Prevention Services, Centers for Dsease Control, Atlanta, GA 30333.
This paper provides an update of new information on the rubella vaccine that has been accumulated over the past 15 years. It addresses four splecific issues that are of interest to infection control practitioners: (1) the risk and degree of joint symptoms after vaccination and revaccination, (2) the duration of vaccine-induced immunity, (3) the protective effect of low levels of vaccine-induced antibody, and (4) risks to the fetus after maternal vaccination. The data support continued vaccination of all young children as well as increased efforts to vaccinate susceptible adolescents and young adults, especially women. Infection control practitioners will find this reference helpful in their hospital’s immunization program for employees. All available data indicate that rubella vaccine is both safe and effective. Efforts must focus on immunizing person.3 who have not been previously immunized, particularly susceptible women in the childbearing years. Immunization of hospital personnel is one part of the overall program to curtail transmission of this disease and eliminate the occurrence of congenital rubella syndrome in the United States.
Literature
Bladder irrigation with povidone-iodine in prevention of urinary-tract infections associated with intermittent urethral catheterisation Van Den Broek PJ, Daha TJ, Mouton RP. Lancet 1:563-565, 1985. Reprint requests: P. J. Van Den Broek, Department of Infectious Diseases and Medical Microbiology, and Infection Control Committee, Leiden University Hospital, The Netherlands.
This investigation was prompted by the observation that 6.9% of 437 patients admitted to the Department of Orthopedics in a 4-month period developed bacteriuria after intermittent catheterization. In a prospective, controlled study, the efficacy of bladder irrigation with povidone-iodine after intermittent catheterization was compared with an untreated control group. In the treated group, 50 ml povidoneiodine 2% was instilled into the bladder and allowed to drain immediately before removal of the catheter. The incidence of bacteriuria in the treated group was 4% (1 of 28) compared with an incidence of 28% (8 of 29) in the untreated group. Bacteiuria was associated with pyuria in the one patient given treatment who developed bacteriuria and in three of the eight patients with no treatment who developed bacteriuria. The results of urine cultures collected 3 days after the last catheterization in patients in both groups were not presented. The authors concluded that irrigation of the urinary bladder with 2% povidone-iodine solution at the end of an episode of urethral catheterization is an effective method to prevent bacterial contamination of the urinary tract. 194
This is an interesting study for infection control practitioners to review. Unfortunately, the numbers are so small in each group that the significance of the observations cannot be evaluated. No difference was noted between the two groups with regard to episodes of bacteriuria accompanied by pyuria. No data are presented regarding the incidence of symptomatic infection or results of cultures taken 3 days or more after the catheter was removed. If therapy with povidone-iodine were recommended for general use, the possible selection of resistant organisms, drug toxicity, and increased costs of catheter care would be causes for concern. Nonetheless, this study presents an interesting new strategy for the prevention of catheter-associated bacteriuria and should be reevaluated by a more definitive clinical trial.
AIDS serology groups
testing
in low= and high-risk
Carlson JR, Bryant ML, Hinrichs SH, et al. JAMA 253:34053408, 1985. Reprint requests: Dr. J. R. Carlson, Department of Medical Pathology, Room 3453, MSI-A, School of Medicine, University of California, Davis, CA 95616.
This study outlines the technical data needed to establish performance standards for the serologic detection of antibody to the acquired immunodeficiency syndrome (AIDS)-associated retroviruses (anti-HTLV-III). In this study, 1257 serum samples collected from both low- and high-risk population groups were tested for anti-HTLV-III by an enzyme-linked immmunosorbent assay (ELISA) method. The sensitivity
Volume
14 Number
August,
1986
4
Reviews
and specificity of the ELISA test were determined by Western blot and immunofluorescence assay (IFA) techniques. The investigators used a relatively low ratio of positive to negative (P/N) (control) reactivity to indicate a positive ELISA test (a P/N ratio of 2 or greater). With this criterion for a positive test, 91 of 1014 unselected low-risk blood donors had falsely positive results by the ELISA test, based on the lack of Western blot confirmation; two true positives were found in this low-risk group. In contrast, 106 of 108 specimens from highrish groups (asymptomatic homosexual men, patients with hemophilia, patients with AIDSrelated complex, and patients with AIDS) were positive by ELISA and confirmed by Western blot and immunofluorescence assays. Four falsenegative ELISA results were found in patients with AIDS. Ten of 69 patients with AIDS had negative results by all three serologic tests. The investigators concluded that the definition for a positive ELISA test that they used (P/N ratio greater than or equal to 2) was very sensitive for detecting antibody positivity but was not very specific. The number of false-positive results necessitates the use of a confirmation test by Western blot or IFA assay to improve the specificity of the test result.
Occupational paramedics
exposure
to hepatitis
B in
Valenzuela TD, Hook EW, Copass MK, Corey L. Arch intern Med 145:1976-1977, 1985. Reprint requests: Dr. Terence D. Valenzuela, Section of Emergency Medicine, College of Medicine, University of Arizona Health Sciences Center, Tucson, AZ 85724.
To determine their occupational risk for hepatitis B infection, 59 Seattle paramedics were tested for hepatitis B serum markers. These personnel were considered to be at risk for hepatitis B infection because they routinely performed invasive procedures such as intravenous line placements, thoracenteses, pericardiocenteses, endotracheal intubations, and control of hemorrhage. In the 12-month period before blood sampling, each paramedic was in-
195
volved in an average of 195 procedures in which there was a high likelihood of exposure to blood or body fluids. Serologic testing revealed evidence of prior hepatitis B infection in 25%, as determined by the presence of hepatitis B surface antibody or hepatitis B e antibody. This rate was five times that in a similar Seattle population. Seropositivity did not correlate with age, race, clinical history, or length of service. The investigators concluded that paramedics are at increased risk of hepatitis B infection and that hepatitis B vaccine should be strongly considered for members of this group.
Some current vaccine
issues
relating
to rubella
Preblud SR. JAMA 254:253-256,1985. Reprint requests: Technical Information Services, Center for Prevention Services, Centers for Dsease Control, Atlanta, GA 30333.
This paper provides an update of new information on the rubella vaccine that has been accumulated over the past 15 years. It addresses four splecific issues that are of interest to infection control practitioners: (1) the risk and degree of joint symptoms after vaccination and revaccination, (2) the duration of vaccine-induced immunity, (3) the protective effect of low levels of vaccine-induced antibody, and (4) risks to the fetus after maternal vaccination. The data support continued vaccination of all young children as well as increased efforts to vaccinate susceptible adolescents and young adults, especially women. Infection control practitioners will find this reference helpful in their hospital’s immunization program for employees. All available data indicate that rubella vaccine is both safe and effective. Efforts must focus on immunizing person.3 who have not been previously immunized, particularly susceptible women in the childbearing years. Immunization of hospital personnel is one part of the overall program to curtail transmission of this disease and eliminate the occurrence of congenital rubella syndrome in the United States.