Blood drawn through valved catheter hub connectors carries a significant risk of contamination.

Infection Control became concerned when bloodstream infection (BSI) rates increased after implementing a needleless valved hub connector. During a 21-month period three different needleless catheter hub connectors were evaluated by quantitatively culturing blood drawn through hub connectors that would have ordinarily been discarded (DBC). DBC drawn through Clearlink™ catheter hub connectors were found to be twice as likely to be positive as DBC drawn through Clave® or Q-syte™ hub connectors (P < 0.04). DBC grew pathogens 46% of the time and skin organisms 54% of the time. Patients with positive DBC were three times more likely to meet Centers for Disease Control (CDC) BSI criteria by DBC cultures than by physician-ordered blood cultures (CBC; P < 0.001). For patients growing pathogens in DBC, 64% had no CBC drawn, the average temperature was lower than for patients with pathogens in CBC (99.3 ± 1.5 ve 100.6 ± 1.9, P = 0.015), and 92% of discharged patients (11 out of 12) were not treated with an antibiotic active against the DBC pathogen. Drawing BC through a catheter hub connector carries a risk of false-positives that could increase BSI rates by up to 3-fold. Further work is necessary to evaluate this concern.

Transmission of hepatitis A by transfusion of blood products.

The transmission of hepatitis A by blood products has been thought to occur rarely or not at all. By measuring IgM antibody to hepatitis A virus, we diagnosed a case of hepatitis A transmitted by the transfusion of a unit of fresh frozen plasma. Since the commercial availability of methods for measuring IgM antibody to hepatitis A, four other well-defined cases of hepatitis A transmitted by blood products have been reported in the literature. We detail our case and the natural history and importance of this clinical entity.

Infections associated with subclavian Uldall catheters.

During a 12-month period, the use of a subclavian vein Uldall catheter (UC) for hemodialysis or plasmapheresis in 27 patients was studied prospectively. Ten patients had ten UC site infections. Organisms associated with these infections included Staphylococcus epidermidis (five), Staphylococcus aureus (four), Proteus mirabilis (two), and Enterococcus (one). The four S aureus infections occurred 1, 2, 4, and 9 days after UC insertion, whereas the five S epidermidis infections occurred 6, 17, 17, 26, and 97 days after insertion. Five patients had associated bacteremias; in one of these patients, the bacteremia was the major cause of death. The incidence of UC site infection and bacteremia based was higher than the incidence of infection reported with any other type of vascular access for hemodialysis. Further studies are necessary to define whether the UC should be routinely employed for temporary vascular access.

Can antibiotic-resistant nosocomial infections be controlled?

Three decades ago infection-control programmes were created to control antibiotic-resistant nosocomial infections, but numbers of these infections have continued to increase, leading many to question whether control is feasible. Meticillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci were major problems during the 1990s. Many hospitals have tried antibiotic control but with limited efficacy against these pathogens. Studies of antibiotic restriction, substitution, and cycling have been promising, but more definitive data are needed. Increased compliance with hand hygiene would help but is unlikely to control this problem alone as a result of frequent contamination of other surfaces even when hands are cleansed and high transmission rates when hand hygiene is neglected. For 17 years, the Centers for Disease Control and Prevention have recommended contact precautions for preventing nosocomial spread of important antibiotic-resistant pathogens. Many studies confirm that this approach works when sufficient active-surveillance cultures are undertaken to detect the reservoir for spread. However, most healthcare facilities have not yet tried this approach.

Impact of air filtration on nosocomial Aspergillus infections. Unique risk of bone marrow transplant recipients.

Bone marrow transplant recipients were found to have a 10-fold greater incidence of nosocomial Aspergillus infection than other immunocompromised patient populations (p less than 0.001) when housed outside of a high-efficiency particulate air (HEPA) filtered environment. Multivariate analysis demonstrated that number of infections, age, and graft-versus-host disease severe enough to require treatment were independent risk factors for development of nosocomial Aspergillus infection in this group. The use of whole-wall HEPA filtration units with horizontal laminar flow in patient rooms reduced the number of Aspergillus organisms in the air to 0.009 colony-forming units/m3, which was significantly lower than in all other areas of the hospital (p less than or equal to 0.03). No cases of nosocomial Aspergillus infection developed in 39 bone marrow transplant recipients who resided in this environment throughout their transplantation period compared with 14 cases of nosocomial Aspergillus infection in 74 bone marrow transplant recipients who were housed elsewhere (p less than 0.001). Thus, although bone marrow transplant recipients had an order-of-magnitude greater risk of nosocomial Aspergillus infection than other immunocompromised hosts, this risk could be eliminated by using HEPA filters with horizontal laminar airflow.

Infected radial artery pseudoaneurysms occurring after percutaneous cannulation.

During a ten-month period in 1988 at our institution, we identified three infected radial artery pseudoaneurysms (RAPAs) associated with arterial lines. A retrospective chart review to 1983 identified three additional cases, all occurring in 1986. In the six-year period of 1983 through 1988, during which approximately 12,500 radial artery catheters were placed, the incidence of RAPA formation was 6/12,500 (0.048 percent). Five of the six cases were associated with Staphylococcus aureus infection. The duration of radial artery cannulation was significantly longer in patients who developed a pseudoaneurysm (12.5 days) than in those patients who did not suffer this complication (4.3 days). Patients in whom infected RAPAs occurred also tended to be older (mean, 71.6 years) than the average age (54 years) for all patients admitted to the intensive care unit (ICU). They also tended to have long stays in the ICU prior to development of RAPA, the shortest stay being 11 days and the average being 51 days. Risk factors for the development of this complication may include advanced age, longer duration of catheterization and hospitalization, and infection with S aureus.

Surveillance for infections associated with vascular catheters.

Intravascular devices are the source of most primary bloodstream infections. Unfortunately, there are few studies that demonstrate how surveillance for catheter-related infection should be done. This article attempts to provide infection control personnel with information necessary to develop such surveillance.

Annual tuberculin skin testing of employees at a university hospital: a cost-benefit analysis.

The usefulness of routine annual tuberculin skin testing (purified protein derivative [PPD]) of hospital employees has been questioned. Between 1984 and the end of 1987 the PPD conversion rates of hospital employees at a university and psychiatric hospital in North Florida were compared. The number of employees in both hospitals were almost equal and compliance with the annual testing was more than 95%. In the psychiatric hospital tuberculosis screening of patients was practiced on admission and annually thereafter. Although no unsuspected smear-positive tuberculosis patients were diagnosed in the psychiatric hospital as compared to four in the university hospital, the annual conversion rates of employees were 0.42% and 0.13%, respectively (p greater than 0.001). However, the ratios of these conversion rates to the incidence of tuberculosis in the counties where these hospitals are located respectively were similar (20.0 vs 24.3, p = 0.7). The community seems be the major source of the PPD conversion. At the university hospital more than +70,000 was spent on the annual PPD testing to discover 15 converters; nine had no or minimal contact with patients and only two complied with isoniazid (INH) prophylaxis. Annual PPD testing is not cost effective in hospitals with a low annual conversion rate among its employees and with low tuberculosis case rates in the hospital and the surrounding community.

Nasal carriage of Staphylococcus aureus among patients receiving allergen-injection immunotherapy: associated factors and quantitative nasal cultures.

OBJECTIVE: To compare the prevalence of nasal Staphylococcus aureus carriage among outpatients receiving allergen-injection immunotherapy with the prevalence among healthy controls and to determine predictors of nasal S. aureus carriage. DESIGN: Survey. SETTING: Allergy clinic of a university hospital. PARTICIPANTS: A volunteer sample consisting of 45 outpatients undergoing desensitization therapy and 84 first- and second-year medical students. RESULTS: The nasal S. aureus carriage rate was significantly higher among patients (46.7%) than among students (26.2%; P=.019). In a multivariate model adjusted for age and gender, the presence of atopic dermatitis or eczema was the only independent predictor of nasal S. aureus carriage (odds ratio [OR], 4.4; 95% confidence interval [CI95], 1.2-16.0; P=.02). The only other participant characteristic associated with nasal S. aureus carriage was immunotherapy with allergen injections (OR, 1.98; CI95, 0.7-6.0), but this association did not reach statistical significance (P=.23). The probability of nasal S. aureus carriage was 88.9% for patients receiving allergen injections and having atopic dermatitis or eczema, and 36.1% for patients receiving allergen injections without atopic dermatitis or eczema. CONCLUSIONS: Patients undergoing desensitization have a higher nasal carriage rate of S. aureus. However, factors other than the regular use of needles, and in particular abnormalities related to the atopic constitution of these patients, may predispose this population for S. aureus carriage.

The importance of nosocomial transmission of measles in the propagation of a community outbreak.

In late January 1985, a measles outbreak occurred at a community hospital in Columbia county, Florida. The outbreak spread throughout the county and to two neighboring counties (Alachua and Marion), resulting in 79 cases with a 29% hospitalization rate. Hospitals represented the site with the highest frequency of transmission. At the Alachua county hospitals, where strict respiratory isolation measures were taken, no secondary cases occurred among hospitalized patients. Two independent risk factors existed for hospitalization: measles exposure in a hospital setting (P less than 0.05) and nonvaccination (P less than 0.001). Of the total measles cases, 24% were under the age of 16 months and 47% of those aged 16 months or older had a history of appropriate vaccination. Columbia county, which experienced 86% of the cases, had a 5% frequency of unvaccinated students compared to 0.6% frequency at Alachua (P less than 0.001) where only 10% of the cases occurred. This outbreak demonstrates the role of uncontrolled nosocomial transmission of measles in the propagation of a community outbreak.

The risk of peripheral vein phlebitis associated with chlorhexidine-coated catheters: a randomized, double-blind trial.

OBJECTIVE: To evaluate the risk of phlebitis associated with chlorhexidine-coated polyurethane catheters in peripheral veins. DESIGN: A randomized, double-blinded trial comparing chlorhexidine-coated polyurethane catheters with uncoated polyurethane catheters. SETTING: A university hospital. PATIENTS: Adult medicine and surgery patients. INTERVENTIONS: Certified registered nurse anesthetists or an infusion team consisting of nurses and physicians inserted the catheters. Catheter insertion sites were scored twice daily for evidence of phlebitis. At the time catheters were removed, a quantitative blood culture was performed, and catheters were sonicated for quantitative culture. RESULTS: Of 221 evaluable catheters, phlebitis developed in 18 (17%) of 105 coated catheters, compared to 27 (23%) of 116 uncoated catheters (relative risk [RR], 0.74; 95% confidence interval [CI95], 0.43-1.26; P = .32). By survival analysis, chlorhexidine-coated catheters had a lower risk of phlebitis during the first 3 days (P = .06), but not when all catheters were considered in both patient groups (P = .31). In the absence of catheter colonization, the incidence of phlebitis was 21% (16/76) and 24% (20/86) for coated and uncoated catheters, respectively (P = .85), whereas in the presence of catheter colonization, the incidence of phlebitis was 14% (1/7) and 80% (4/5) for coated and uncoated catheters, respectively (RR, 0.18; CI95, 0.03-1.15; P = .07). CONCLUSION: The risk of phlebitis in the presence of catheter colonization was 82% lower for chlorhexidine-coated polyurethane catheters compared to otherwise identical uncoated catheters.

Natural history of bloodstream infections in a burn patient population: the importance of candidemia.

Because of a perceived increase in Candida bloodstream infections in our burn unit, we retrospectively reviewed all the microbiologic data and the medical records of 209 patients with burns admitted during a 42-month period. Twice weekly burn wound cultures demonstrated that Candida species were the tenth most frequently isolated organisms (69/191 patients, 36%). Despite the low frequency of isolation from burn wounds, Candida species were the most common organisms found in blood cultures and urine cultures. Of 49 patients with positive blood cultures, 16 (33%) had clinically significant culture growth of yeasts: Candida albicans, 12; Candida parapsilosis, 2; Candida tropicalis, 1; and Torulopsis glabrata, 1. Patients with candidemia were more likely than patients with blood culture growth of other organisms to have burn wound cultures that grew Candida (15/16 vs 21/33, p = 0.02), larger burns (61% vs 38%, p < 0.001), and death (63% vs 27%, p = 0.02). Multivariate analysis demonstrated that the total number of blood cultures with microorganism growth and large burn size were the greatest independent risk factors for candidemia. These data demonstrate that yeasts are pathogens of major importance in patients with burns, suggesting that in patients with burns who have suspected sepsis and large burn injury or a previous bacteremia, strong consideration should be given to administration of amphotericin B initiation of empiric antibacterial therapy.

Uncontrolled nosocomial rotavirus transmission during a community outbreak.

Between Jan. 11 and March 31, 1983, 60 pediatric patients were diagnosed with rotavirus gastroenteritis. Of these cases 24 were community acquired, 29 were nosocomial, and 7 were of undetermined origin. Despite intensive infection control efforts, nosocomial transmission continued as long as patients with community-acquired cases were admitted. The use of disinfectants and germicides that were ineffective against rotavirus may have contributed to the continued nosocomial spread during a community outbreak.

Quantitative tip culture methods and the diagnosis of central venous catheter-related infections.

The diagnostic usefulness of two quantitative catheter culture methods was compared in a prospective study of central venous arterial catheters. The roll-plate method followed by sonication was used to culture 177 catheters from 85 patients, and the sonication method was used to culture 136 catheters from 68 patients. All patients were evaluated for catheter-related infections. Catheter-related infections were associated with greater than or equal to 100 colony-forming units (CFU) isolated from catheter tips by either roll plate (p = 0.01) or sonication (p less than 0.001). The sensitivity, specificity, and positive and negative predictive values of greater than or equal to 10(3) CFU by roll plate for catheter-related septicemia were 56%, 97%, 63%, and 96% compared with 93%, 95%, 76%, and 99%, respectively, for the same level by sonication. For central venous and arterial catheters, the sonication method can distinguish infection from contamination and is superior to the roll-plate method in that it may offer a more sensitive and predictive alternative in the diagnosis of catheter-related septicemia.

Acquired immune deficiency syndrome. A perspective for the medical practitioner.

AIDS is a new disease process with complications and management problems unlike anything ever seen before. An attempt has been made to summarize the available information about its various clinical presentations and how to manage them. Subjects covered will include associated malignancies, infections, transmissibility, prodromal states, and infection control issues.

Vascular-access infections in hospitalized patients.

Vascular catheters are a common source of nosocomial infections, although many of these infections are potentially preventable. A long duration of catheterization, multiple catheter manipulations, the inexperience of some inserters, use of transparent plastic dressings, violations of aseptic technique, the use of multilumen catheters, and inadequate sterilization of reusable pressure transducers all increase the risk of these infections. The only interventions that have been proved to reduce the risk are standardized insertion and maintenance technique by an intravenous-therapy team, preinsertion skin preparation with chlorhexidine gluconate, and the use of topical antibiotics at the insertion site. The goal of the physician should be to prevent catheter infection, because the treatment of established infection can be difficult and costly. Treatment must be individualized for each patient on the basis of the clinical presentation and the causative organism.

Microbial interactions with catheter material.

The use of central venous catheters to deliver parenteral nutrition therapy is often complicated by infection. The original source of these infections has been debated but it appears that organisms colonizing the skin or those contaminating the catheter hub are most often responsible. Before forming a biofilm, an organism must first successfully attach to a surface. To do this, microbes have evolved strategies that allow them to adhere to surfaces and evade forces that would favor their detachment. Once a biofilm is formed on a catheter, the organisms are relatively safe from a host immune response and antibiotics. In this review, what is known about these interactions is discussed.

Nonurban male homosexuals: epidemiologic, immunologic and virologic characteristics.

Twenty asymptomatic male homosexuals living in North Carolina were evaluated looking at epidemiologic, immunologic and virologic characteristics. In ten subjects selected for inhalant nitrite use a significantly higher frequency of multiple drug abuse and a trend toward greater sexual promiscuity was found in comparison with ten nonnitrite users. None of the 20 subjects had chronic lymphadenopathy. Cytomegalovirus (CMV) was not found in urine, blood or throat washings, but was found in 29% of the subjects' semen specimens--a finding that was significantly linked (P less than .05) to the presence of CMV IgM antibody in serum. There were no abnormal helper lymphocytes: suppressor T lymphocyte ratios (all greater than 1.3) and lymphocyte mitogen stimulations were not different from heterosexual controls in contrast to frequent abnormalities reported in male homosexuals in metropolitan areas. If these immunologic findings are reproducible, they may be important in understanding why the Acquired Immunodeficiency Syndrome has clustered in large cities.