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Biomedical subjects

D J Weber

Publications and source records attributed to D J Weber.

At least 145 records · Page 8Linked to original sources
PubMed1991

Disinfection practices for endoscopes and other semicritical items.

OBJECTIVE: To determine the disinfection practices employed by North Carolina hospitals for endoscopes and other semicritical patient care items and to discuss minimally acceptable disinfection procedures for these items. DESIGN: A survey questionnaire was mailed to all North Carolina hospitals to identify their disinfection practices, and a literature review was conducted to ascertain studies that evaluated disinfection techniques for certain semicritical items. PARTICIPANTS: Questionnaires were returned by 107 of 167 (64%) North Carolina acute-care hospitals. RESULTS: Most hospitals (91%) used a glutaraldehyde-based disinfectant (59%, 2% glutaraldehyde; 29%, 0.13% glutaraldehyde-0.44% phenol-0.08% phenate; 3%, either); half (51%) of the hospitals immersed the endoscope into disinfectant for greater than or equal to 20 minutes, but 44% immersed for less than or equal to 10 minutes; nearly all hospitals (97%) disinfected endoscopes at room temperature. Hospitals rinsed the endoscope with sterile water (16%), tap water (54%), tap water followed by alcohol rinse (27%), or other (2%); 58% of the hospitals treated endoscopes from patients infected with human immunodeficiency virus (HIV), hepatitis B virus (HBV), or Mycobacterium tuberculosis differently (81%, ethylene oxide [ETO] sterilization; 10%, increased exposure time; 10%, other). Twenty percent of the hospitals used an automated washer for processing endoscopic instruments. Rigid endoscopes (e.g., arthroscopes, laparoscopes) were primarily high-level disinfected (57%), ETO sterilized (17%), or either (13%). The disinfection strategies for other semi-critical items (e.g., applanation tonometers, cryosurgical instruments, and diaphragm fitting rings) were highly variable for the responding hospitals. CONCLUSIONS: This survey indicated the presence of a wide variety of practices for handling semicritical patient care items, many of which are inconsistent with current recommendations. To help establish minimally acceptable disinfection procedures for some patient care instruments (e.g., arthroscopes, laparoscopes, tonometers), the scientific literature was reviewed and recommendations were made.

Disinfection↗
PubMed1991

Short courses of antibiotics in selected febrile neutropenic patients.

To evaluate their policy of discontinuing broad spectrum antibiotics in patients with negative cultures who become afebrile but remain neutropenic, the authors retrospectively reviewed the charts of all pediatric patients diagnosed with cancer between 1980 and 1986. Two hundred seventy-one children had 385 admissions for infectious complications during the study period. In 39 of those episodes (9%), the patients had negative cultures, became afebrile, and were discharged with absolute neutrophil counts of less than 1000 cells/mm3 (mean 390 cells/mm3). They received relatively short courses of antibiotics with a median duration of 4 days. Only four of these patients became febrile during the followup period and there were no fatalities. Given the benign course of these patients, recommendations for prolonged antibiotic courses should be reconsidered.

Anti-Bacterial Agents↗
PubMed1991

Use of antimicrobial drugs in adults before and after removal of a restriction policy.

The effects on the quantity and quality of antimicrobial drug use of removing an antimicrobial restriction policy are reported. Monthly totals for the number of courses of antimicrobial therapy and expenditures based on grams used were obtained from pharmacy records on adult inpatients for a portion (July-December 1987) of the restriction policy term and for the six months (July-December 1988) immediately after the policy ended. Data were obtained for nine restricted drugs and for three that were never restricted. Retrospective drug-use reviews were conducted for ceftazidime and imipenem-cilastatin. For the restricted agents, the total number of courses of therapy increased by 158% after the restriction policy was removed, and total expenditures increased by 103%. There were no significant changes in the number of courses of therapy or cost for the unrestricted antimicrobials. In the postrestriction period, ceftazidime and imipenem-cilastatin were used more often in patients who were less critically ill. Inappropriate use of imipenem-cilastatin occurred significantly more often after the restrictions were removed. Other factors potentially affecting the use of antimicrobials, such as patient age and the incidence of nosocomial infections, did not differ substantially between the two periods. The removal of an antimicrobial restriction policy resulted in increased use of and higher expenditures for previously restricted agents, as well as an increase in the inappropriate use of at least one agent.

Adult↗
PubMed1991

Rocky Mountain spotted fever.

Rocky Mountain spotted fever, the most prevalent rickettsial disease in the United States, is one of the most severe of all infectious diseases. It remains an important infectious disease because of its prevalence, the difficulty of clinical diagnosis, potentially fatal outcome, and lack of a widely available sensitive and specific diagnostic test during the acute stage of the illness.

Animals↗
PubMed1991

Infections resulting from animal bites.

Animal bites are a major public health problem. This article reviews the epidemiology and treatment of animal bites. The epidemiology, clinical presentation, and treatment of infections caused by Pasteurella multocida and Capnocytophaga canimorsus (DF-2) are reviewed in detail.

Animals↗
PubMed1991

Infection control strategies relevant to employee health.

A well organized employee health service is a key component of an effective infection control program. All health care providers should be immune to mumps, measles, rubella, tetanus, and polio. Hepatitis B vaccine should be offered to all workers who have contact with blood. Employees with signs and symptoms of infectious diseases should be evaluated by Employee Health and follow work restrictions. Employees with exposure to communicable diseases should be evaluated for prophylaxis.

Communicable Disease Control↗
PubMed1990

Diverse interactions between the individual mutations in a double mutant at the active site of staphylococcal nuclease.

In principle, the quantitative effect of a second mutation on a mutant enzyme may be antagonistic, absent, partially additive, additive, or synergistic with respect to the first mutation. Depending on the kinetic or thermodynamic parameter measured, the D21E and R87G mutations of staphylococcal nuclease exhibit four of these five categories of interaction in the double mutant. While Vmax of the R87G single mutant of staphylococcal nuclease is 10(4.8)-fold lower than that of the wild-type enzyme and the Vmax of the D21E single mutant is 10(3.0)-fold below that of wild type, the double mutant D21E + R87G was found to lose a factor of only 10(4.1) in Vmax relative to wild type, rather than the product of the two single mutations (10(7.8)). These results suggest antagonistic structural effects of the individual R87G and D21E mutations. An alternative explanation for the nonadditivity of effects, namely, the separate functioning of these residues in a stepwise mechanism involving the prior attack of water on phosphorus followed by protonation of the leaving group by Arg-87, is unlikely since no enzyme-bound phosphorane intermediate (less than 1% of [enzyme]) was found under steady-state conditions on the R87G mutant by 31P NMR at 242.9 MHz. Like the effects on Vmax, quantitatively similar antagonistic effects of the two mutations were detected on the binding of divalent cations in binary enzyme-Ca2+ and enzyme-Mn2+ complexes and in the ternary enzyme-Ca2(+)-5'-pdTdA complex, suggesting that the effects on Vmax result from antagonistic structural changes at the Ca2+ binding site. Simple additive weakening effects of the two mutations were found on the binding of the substrate 5'-pdTdA, in both the absence and the presence of the divalent cations, Mn2+ and Ca2+. However, synergistic effects of the two mutations were found on the binding of the substrate analogue 3',5'-pdTp, profoundly weakening its binding to the double mutant in both the absence and the presence of divalent cations. Such synergistic effects of the two mutations may result from negative cooperativity or strain in the binding of 3',5'-pdTp to the wild-type enzyme. It is concluded that the quantitative interactions of two active-site mutations of an enzyme can vary greatly depending on which parameter of the enzyme is measured. When the two mutations interact in the same way on several parameters, a common underlying mechanism is suggested.

Binding Sites↗
PubMed1990

Wound infection rates after invasive procedures in HIV-1 seropositive versus HIV-1 seronegative hemophiliacs.

One-hundred and two patients with hemophilia A, hemophilia B, or acquired antibody to factor VIII who had undergone invasive procedures were cross referenced with patients participating in an ongoing prospective natural history study of HIV-1 infection in hemophiliacs. Matching revealed that HIV-1 status was known for 83 patients (83%) who had undergone 169 procedures between July 1979 and April 1988. Invasive procedures were classified as clean in 108 patients (63.9%), clean-contaminated in 45 (26.6%), contaminated in 2 (1.2%), and infected in 14 (8.3%). Wound infection rates by HIV-1 status were as follows (95% confidence intervals): HIV+ 1.4% (0% to 5%), HIV- 0% (0% to 9%), and procedure before testing HIV+ 1.5% (0% to 6%). There were no significant differences between the wound infection rates of HIV-positive and HIV-negative hemophiliacs nor in the wound infection rate among all three subgroups of patients (p greater than 0.5, Fisher's Exact Test). We conclude that surgery in HIV-1-infected patients who have not progressed to AIDS does not entail an increased risk of postoperative wound infections.

HIV Seropositivity↗
PubMed1990

Effect of methodology, dilution, and exposure time on the tuberculocidal activity of glutaraldehyde-based disinfectants.

The Association of Official Analytical Chemists (AOAC) test for assessing the tuberculocidal activity of disinfectants has been shown to be variable. A modified AOAC test, which substituted Middlebrook 7H9 broth as the primary subculture medium and used neutralization by dilution, was compared with the standard AOAC method to assess the mycobactericidal activity of three glutaraldehyde-based disinfectants at 20 degrees C and various exposure times. These changes had a marked effect on results, with the modified AOAC test providing more positive penicylinders per 10 replicates in 12 of the 13 comparisons that provided positive results. These differences were observed with both Mycobacterium bovis (ATCC 35743) and a clinical isolate of Mycobacterium tuberculosis. The effects of various exposure times to and dilutions of the glutaraldehyde-based disinfectants were also examined. The minimum exposure time needed to inactivate reliably M. bovis or M. tuberculosis with 2% glutaraldehyde was 20 min at 20 degrees C. Diluting 2% glutaraldehyde caused a significant decline in mycobactericidal activity. Modification of the standard AOAC test to improve its sensitivity in detecting the failure of disinfectants to inactivate mycobacteria is indicated.

Aldehydes↗
PubMed1990

Manual ventilation bags as a source for bacterial colonization of intubated patients.

A group of 14 intensive care unit (ICU) patients were studied to determine if manual ventilation bags (MVB) could serve as a source of bacterial or fungal pathogens that could colonize the respiratory tract of intubated patients. A total of 51 cultures were simultaneously obtained of patient's sputum, the exterior MVB surface, MVB port, and MVB interior (postexhalation valve). Pathogens colonizing or infecting the respiratory tract of intubated ICU patients were frequently simultaneously present on the exterior surface of the MVB and inside the MVB port used to connect the MVB with the endotracheal tube. In addition, coagulase-negative staphylococci and yeast were frequently present on the exterior surface of the MVB. The interior of the MVB was usually sterile. In three instances pathogens were isolated from the MVB before isolation from the patient's sputum. MVB may serve as a source for colonizing the respiratory tract of intubated ICU patients and/or the hands of medical personnel. The exterior surface and port of MVB should be cleaned of visible debris and disinfected at least once a day.

Bacteria↗
PubMed1990

Causes of adverse responses to soybean milk replacers in young calves.

Sixty Holstein bull calves were randomly assigned to one of three treatment groups following an initial 3-d colostrum feeding period. They were fed either whole cows' milk or ethanol-extracted or hexane-extracted soy flour in milk replacers to 6 wk of age. These products were used to identify possible causative factors associated with adverse responses to soybean in milk replacers. Average weight gains to 6 wk of age were 13.8, 7.3, and 2.8 kg and mortality was 0/20, 4/20, and 9/20 for calves fed milk, ethanol-extracted soy, and hexane-extracted soy, respectively. Heart rates (beats/min) were increased by the soy flours: 99.1 (ethanol extracted) and 116.3 (hexane extracted) versus 87.6 (milk). There was also an increased respiratory rate (breaths/min) with 67.6 and 61.1 versus 41.6 for the same treatment groups. Intradermal wheal growths verified an allergic sensitivity to the soybean products. Serum prostaglandin F2 alpha was 22% higher in the serum of calves fed the hexane-extracted soy milk replacer than in the serum of calves fed milk. Phenolic compounds in the soybean flour were implicated as possible causative factors in the adverse responses to the soybean milk replacers. Ethanol extraction of the soy flour was more effective than hexane extraction in removing phenolic compounds (2.19 vs. 1.00% phenolics).

Animal Feed↗
PubMed1989

Simultaneous determination of methylprednisolone and methylprednisolone 21-[8-[methyl-(2-sulfoethyl)amino]-8-oxooctanoate] sodium salt in human urine by high-performance liquid chromatography with ultraviolet detection.

A reversed-phase high-performance liquid chromatographic assay with ultraviolet detection at 243 nm has been developed for the quantitative determination of methylprednisolone (MP) and methylprednisolone 21-[8-[methyl-(2-sulfoethyl)amino]-8-oxooctanoate] sodium salt (MPSO) in human urine following therapeutic doses in humans. The assay procedure involves stabilization of urine samples by addition of disodium ethylenediaminetetraacetic acid (Na2EDTA) and ion-pair extractions of MPSO using tetraethylammonium chloride (TEACl) as the counter ion. After extracting both drugs and internal standard into chloroform, the extract was evaporated to dryness under nitrogen. The resulting residue was reconstituted in 200-500 microliters of mobile phase and chromatographed on an IBM C18 reversed-phase column (5 microns). The mobile phase was a mixture of water-acetonitrile-isopropanol (71.2:18.8:10.0, v/v) containing 75 microliters of 0.1 M hydrochloric acid and 0.450 g of TEACl per liter. Propyl p-hydroxybenzoate was used as an internal standard. The extraction efficiencies of MP and MPSO were greater than 90% using the ion-pairing agent TEACl. The chromatographic responses were linear up to about 200 micrograms/ml for MP and 80 micrograms/ml for MPSO and had sufficient precision and accuracy to provide quantitative data from human urine. The assay detection limit was about 8 ng/ml for MP and 25 ng/ml for MPSO in human urine. Stability studies in urine indicated that without Na2EDTA stabilization and at room temperature, rapid degradation of MPSO occurred in urine. Addition of EDTA to the urine specimen and storage at -70 degrees C increased the stability of MPSO, and little or no degradation was observed in urine stored for more than 60 days. The method has been used in the simultaneous determination of MP and MPSO in urine specimens obtained from a single-dose tolerance study of MPSO in normal male volunteers.

Adolescent↗
PubMed1989

Horizontal transmission of hepatitis B virus.

Meta-analysis of seroprevalence surveys shows that horizontal transmission of hepatitis B virus (ie, that occurring without apparent parenteral, sexual, or perinatal exposure) is common in areas endemic for the virus. It occurs especially in pre-adolescent children. In developed countries, where endemicity of hepatitis B virus is low, horizontal transmission (probably via saliva or open wounds) may occur in households with a persistent carrier, but it is less efficient a means of infection than is sexual or perinatal transmission. Horizontal transmission also seems possible in pre-school day-care centres in developed countries, despite the small numbers of carriers in such places.

Adolescent↗
PubMed1989

Invasive aspergillus infection: possible non-ward common source within the hospital environment.

Six immunocompromised patients housed in widely separated portions of a hospital campus developed invasive aspergillosis during a single month. This represented a significant increase (P less than .001) in the number of cases observed over the 3 years which included this event (19 cases in 36 months). Epidemiological investigation suggested that this cluster of cases was due to a common source outbreak related to construction activity in a central radiology suite serving the hospital. Such non-ward exposures to nosocomial hazards are becoming increasingly important for immunosuppressed hosts.

Adult↗
PubMed1989

Pseudoepidemic of Rhodotorula rubra in patients undergoing fiberoptic bronchoscopy.

Between March and June 1988, Rhodotorula rubra was isolated from the bronchial washings of 30 of 56 (54%) patients undergoing bronchoscopy at a North Carolina community hospital. Pulmonary disease consistent with invasive fungal pneumonia was not apparent for any patient. Repeat sputum cultures were performed on 11 patients, none of whom were positive for R rubra. Investigation revealed fungal contamination of two brushes used to clean the bronchoscope channels and one positive sample of the tub water used to test the integrity of the bronchoscope prior to cleaning and disinfection. Control measures instituted were high-level disinfection of all equipment used to clean the bronchoscopes, including the brushes, complete air drying of the bronchoscopes before storing and storage of equipment in closed cabinets. An additional case one month after instituting these measures prompted the addition of a final 70% ethyl alcohol rinse of the bronchoscopes immediately prior to storage. Over a six-month period no additional cases have been identified. Despite published disinfection guidelines, pseudoepidemics and infections from contaminated equipment continue to appear. This pseudoepidemic investigation revealed a site for contaminating bronchoscopes that has not been previously reported, the inner cannula cleaning brushes. This emphasizes the need for stringent adherence to recommended cleaning and disinfection guidelines.

Adult↗
PubMed1989

Multiple nosocomial infections. An incidence study.

Prospective surveillance for nosocomial infections was performed for a five-year admission cohort (1980-1984) at North Carolina Memorial Hospital. One or more nosocomial infections developed in 2,662 patients (2.6%) from 102,206 patients at risk; greater than or equal to 2 nosocomial infections developed in 775 of these 2,662 patients (29.1%), and greater than or equal to 3 nosocomial infections in 304 of 775 patients with greater than or equal to 2 infections (39.2%). Hospital stay was significantly prolonged for infected compared with never-infected patients (38.1 vs. 7.9 days, p less than 0.0001) and for multiply-infected versus once-infected patients (57.9 vs. 30.0 days, p less than 0.0001). Total nosocomial infections numbered 4,031 with 2,144 multiple infections (53%); the average number of nosocomial infections per infected patient was 1.5 (4,031 infections in 2,662 patients). Among all nosocomial infections, 64% of bacteremias, 55% of respiratory infections, 55% of surgical wound infections, and 40% of urinary tract infections occurred in patients with multiple nosocomial infections. Surgical patients had 56% of multiple infections. Intensive care unit patients had significantly more multiple infections than non-intensive care unit patients. Nosocomial infections in intensive care unit patients were 71% multiple nosocomial infections. The probability of developing multiple infections was 11 times greater after the first infection occurred. This emphasizes the need to prevent initial nosocomial infections and to identify risk factors for multiple nosocomial infections. Determining risk factors for multiple nosocomial infections could focus infection control efforts on a subpopulation of patients who acquire over 50% of all nosocomial infections and who have significantly prolonged and costly hospital stays.

Adolescent↗