Contralateral hydrothorax following subclavian catheter replacement using a guidewire.

Replacement of central venous catheters over a guidewire is now practiced throughout the United States. Although potential mechanical complications of this technique have been mentioned in the literature, few such complications have been documented. We report a patient who suffered a fatal contralateral hydrothorax following replacement of a central venous catheter using the guidewire technique.

Validation of surgical wound surveillance.

OBJECTIVE: To determine the sensitivity and specificity of standard infection control surveillance techniques for the identification of surgical wound infections. DESIGN: Surveillance data collected by three infection control practitioners (ICPs) was compared to surveillance data collected simultaneously by a gold standard observer. SETTING: University-affiliated, tertiary care hospital. METHODS: Using standard infection control surveillance techniques (chart review and discussions with patients' nurses and physicians), ICPs collected surveillance data on patients on the General Surgery and Trauma Surgery Services on days 4 and 7 after surgery and then weekly for 30 days or until patients were discharged from the hospital. Simultaneously, a hospital epidemiologist collected surveillance data and examined each patient's wound daily. RESULTS: Nine hundred twenty-five surgical patients including 537 trauma cases and 388 elective general surgery cases were followed postoperatively. The ICPs identified 67 surgical wound infections, and the hospital epidemiologist identified 80 surgical wound infections for a sensitivity of 83.8% with a 95% confidence interval (CI95) of 75.7% to 91.9%. Specificity was 99.8% with a CI95 of 99% to 100%. The sensitivity was the same for trauma surgery and general surgery, but incisional wound infections were more difficult to identify than deep wound infections. During a second validation period, sensitivity was 92.3% with a CI95 of 62% to 100%. CONCLUSIONS: Standard infection control surveillance techniques have the same sensitivity for detection of surgical wound infections as they do for identification of other nosocomial infections. Accurate data on surgical wound infections can be collected without direct examination of surgical wounds.

Validation of surgical wound classification in the operating room.

OBJECTIVE: To determine the accuracy with which circulating nurses (CNs) classify surgical procedures by risk of contamination in the operating room. DESIGN: Classification of surgical procedures by CNs was compared with the classification of surgical procedures by a physician observer. SETTING: University-affiliated, tertiary care hospital. METHODS: Circulating nurses used the traditional wound classification system of clean, clean-contaminated, contaminated, and dirty-infected to classify surgical wounds in the operating room. A physician remained in the operating room throughout each of 100 surgical procedures and simultaneously classified surgical wounds without the knowledge of the CNs. RESULTS: Classification of surgical wounds by CNs was compared with classification by the physician observer for 50 cases in general surgery and 50 cases in trauma surgery. Compared with the physician observer, the overall accuracy of classification by CNs was 88% (95% confidence interval [CI] of 81.6% to 94.4%; Kappa statistic, 0.83). Classification of surgical wounds was more difficult in trauma surgery (accuracy of 82%) than in general surgery (accuracy of 94%). Accuracy increased for both services when surgical wounds were classified into just two categories (clean or clean-contaminated versus contaminated or dirty-infected). CONCLUSIONS: Surgical wounds can be classified in the operating room with a high degree of accuracy by CNs. Classification was more difficult in trauma than in general surgery, but classification in trauma surgery improved with feedback to and additional education of CNs. The accuracy of classification by CNs was even higher when classifications were divided into just two categories.

A prospective study of infections in hemodialysis patients: patient hygiene and other risk factors for infection.

We performed a prospective randomized study on 71 patients on chronic outpatient hemodialysis to determine whether a sterile technique was better than a clean technique for preparation of the skin over the vascular access site prior to cannulation. In addition, we wanted to determine overall and site-specific infection rates, microbial etiologies of infection, and risk factors for infection. The overall infection rate was 4.7 infections per 100 dialysis months; the vascular access-site infection rate was 1.3 infections per 100 dialysis months; and the rate for bacteremia was 0.7 cases per 100 dialysis months. Staphylococcus aureus was the most common pathogen, but infections were equally divided between gram-positive cocci and gram-negative bacilli. Advanced age (P = 0.02), a low Karnofsky activity score (P = 0.05), poor hygiene (P = 0.0004) and number of hospitalizations (P = 0.0002) were risk factors for infections in general while only poor hygiene (P = 0.002) was a risk factor for vascular access-site infection. Sterile preparation of the skin over the vascular access site was no more effective at preventing infection than was clean technique (P = 0.80). Maintenance of good personal hygiene may be one of the most important measures for prevention of infections in hemodialysis patients.

Outbreak of vancomycin-resistant enterococci in a burn unit.

OBJECTIVE: To investigate and control an outbreak of colonization and infection caused by vancomycin-resistant enterococci (VRE) in a burn intensive care unit (BICU). DESIGN: Epidemiological investigation, including multiple point-prevalence culture surveys of patients and environment, cultures from hands of healthcare workers (HCWs), pulsed-field gel electrophoresis (PFGE) typing of patient and environmental isolates, case-control study, and institution and monitoring of control measures. SETTING: BICU in an 800-bed university medical center in Galveston, Texas. RESULTS: Between June 6, 1996, and July 14, 1997, 21 patients were colonized by VRE, and 4 of these patients developed bacteremia. Of 2,844 environmental cultures, 338 (11.9%) were positive, but all hand cultures from HCWs were negative. PFGE typing indicated that the outbreak was clonal, with VRE isolates from patients differing by < or =4 bands from the index case. Thirteen of 14 environmental isolates varied by < or =4 bands from the pattern of the index case. A case-control study analyzed by exact logistic regression identified diarrhea (odds ratio [OR], 43.9; 95% confidence interval [CI95], 5.5-infinity; P=.0001) and administration of an antacid (OR, 24.2; CI95, 2.9-infinity; P=.002) as independent risk factors for acquisition of VRE. During a 5-week period in October and November 1996, all patient and 317 environmental cultures were negative for VRE. The outbreak recurred from a contaminated electrocardiogram lead that had not been identified during the prior 5 weeks. VRE were finally eradicated from the BICU in July 1997, using barrier isolation and a very aggressive environmental decontamination program. CONCLUSIONS: A VRE outbreak in a BICU over 13 months was caused by a single clone. After apparent eradication of VRE from a BICU, recrudescence of the outbreak occurred, evidently from a small inapparent source of environmental contamination. Changes in gastrointestinal (GI) tract function (motility) and administration of medications, other than antibiotics, that have an effect on the GI tract may increase the risk of GI tract colonization by VRE in burn patients. Application of barrier isolation and an aggressive environmental decontamination program can eradicate VRE from a burn population.

Comparison of three methods to recover vancomycin-resistant enterococci (VRE) from perianal and environmental samples collected during a hospital outbreak of VRE.

OBJECTIVE: To establish an efficient and sensitive technique for recovering vancomycin-resistant enterococci (VRE) from perianal and environmental samples collected during implementation of control measures for an outbreak of VRE. DESIGN: Perianal and environmental samples were collected in triplicate on sterile swabs. One swab was used to inoculate a selective broth medium containing 6 pg of vancomycin and 8 pg of ciprofloxacin per mL, one to inoculate Campylobacter agar containing 10 microg/mL of vancomycin, and one to inoculate Enterococcosel agar containing 8 microg/mL of vancomycin. SETTING: Samples were collected in the intensive care units of a 600-bed university hospital over a period of 2 months. SAMPLE SELECTION: Patients and their immediate environment were sampled if they resided in a ward with a patient known to be colonized or infected with VRE. RESULTS: Of the 88 perianal samples obtained from 63 patients, 37 were positive for VRE by broth culture, with 36 also recovered on both types of solid media (sensitivity, 97.3%; negative predictive value, 98.1%). Of the initial samples collected from each of the 63 patients, 20 were positive for VRE by all methods. Of the 500 environmental samples cultured, 139 were positive for VRE in broth, with only 33 recovered on Campylobacter agar (sensitivity, 23.7%; negative predictive value, 77.2%) and 22 on Enterococcosel agar (sensitivity, 15.8%; negative predictive value, 75.2%). CONCLUSIONS: Our data indicate that, when performing surveillance cultures during an outbreak of VRE, use of an enrichment broth medium is required to recover VRE contaminating environmental surfaces; however, direct inoculation to selective solid medium is adequate to recover VRE in patient perianal specimens.

Risk factors for colonization or infection due to methicillin-resistant Staphylococcus aureus in HIV-positive patients: a retrospective case-control study.

OBJECTIVE: To determine the risk factors for colonization or infection with methicillin-resistant Staphylococcus aureus in human immunodeficiency virus (HIV)-infected patients. DESIGN: Retrospective matched-pair case-control study. SETTING: Continuity clinic and inpatient HIV service of a university medical center. POPULATION: Patients with HIV infection from the general population of eastern and coastal Texas and from the Texas Department of Criminal Justice. DATA COLLECTION: Patient charts and the AIDS Care and Clinical Research Program Database were reviewed for the following: age, race, number of admissions, total hospital days, presence of a central venous catheter, serum albumin, total white blood cell count and absolute neutrophil count, invasive or surgical procedures, any cultures positive for S. aureus, and a history of opportunistic illnesses, diabetes, or dermatologic diagnoses. Data also were collected on the administration of antibiotics, antiretroviral therapy, steroids, cancer chemotherapy, and subcutaneous medications. RESULTS: In the univariate analysis, the presence of a central venous catheter, an underlying dermatologic disease, lower serum albumin, prior steroid therapy, and prior antibiotic therapy, particularly antistaphylococcal therapy or multiple courses of antibiotics, were associated with increased risk for colonization or infection with methicillin-resistant S. aureus. Multivariate analysis yielded a model that included presence of a central venous catheter, underlying dermatologic disease, broad-spectrum antibiotic exposure, and number of hospital days as independent risk factors for colonization or infection with methicillin-resistant S. aureus. CONCLUSIONS: In our HIV-infected patient population, prior hospitalization, exposure to broad-spectrum antibiotics, presence of a central venous catheter, and dermatologic disease were risk factors for acquisition of methicillin-resistant S. aureus.

Clinical predictors of infection of central venous catheters used for total parenteral nutrition.

To identify predictors of infection in catheters used for total parenteral nutrition (TPN), clinical and microbiological data were prospectively collected on 169 catheter systems (88 patients). Based on semiquantitative catheter cultures, infection was associated with a positive insertion site skin culture taken close to the time of catheter removal (relative risk [RR] = 4.50), especially one yielding greater than or equal to 50 colonies of an organism other than coagulase-negative staphylococci. Infection was also associated with erythema at the insertion site greater than 4 mm in diameter (RR = 2.93). In a subset of 67 catheters for which blood cultures were obtained, infection was also associated with a positive peripheral venous blood culture (RR = 5.90) and a positive central venous blood culture obtained through the catheter (RR = 5.44). Based on a logistic regression model, periodic cultures of the insertion site should be useful in evaluating subsequent fever in stable patients with indwelling central venous catheters. Another source of fever is likely if inflammation is absent and there is either no colonization or there is colonization by less than 50 colonies of coagulase-negative staphylococci at the insertion site. Conversely, the catheter should be removed and cultured semiquantitatively if the site is colonized by an organism other than coagulase-negative staphylococci. We suggest that blood culture results add little to the risk estimate in these situations.

Clinical infection control in gene therapy: a multidisciplinary conference.

Gene therapy is being studied for the treatment of a variety of acquired and inherited disorders. Retroviruses, adenoviruses, poxviruses, adeno-associated viruses, herpesviruses, and others are being engineered to transfer genes into humans. Treatment protocols using recombinant viruses are being introduced into clinical settings. Infection control professionals will be involved in reviewing the safety of these agents in their clinics and hospitals. To date, only a limited number of articles have been written on infection control in gene therapy, and no widely available recommendations exist from federal or private organizations to guide infection control professionals. The goals of the conference were to provide a forum where gene therapy experts could share their perspectives and experience with infection control in gene therapy and to provide an opportunity for newcomers to the field to learn about issues specific to infection control in gene therapy. Recommendations for infection control in gene therapy were proposed.

Nosocomial pneumonia. Diagnosis and prevention.

Ventilator-associated pneumonia (VAP) is an important complication in patients with respiratory failure who undergo endotracheal intubation and mechanical ventilation. VAP cannot be accurately diagnosed by clinical or radiographic criteria or culture of endotracheal aspirates; however, it can be accurately diagnosed by histopathologic examination of lung tissue, rapid cavitation of a pulmonary infiltrate, culture of empyema fluid, percutaneous lung needle aspiration, simultaneous recovery of the same microorganism from cultures of respiratory secretions, and blood and quantitative culture of lower respiratory tract secretions obtained by bronchoscopy. VAP can be prevented by proper decontamination and use of ventilatory support equipment, practice of proper nursing techniques during care of the mechanically ventilated patient, and use of face mask ventilation in selected patients.

Gentamicin and tobramycin penetration into burn eschar. Pharmacokinetics and microbiological effects.

This study was designed to determine whether intravenously administered gentamicin sulfate and tobramycin sulfate penetrate into the eschar of patients with severe burns. In addition, each antibiotic's pharmacokinetics in serum and the effect on eschar microbiology were determined. Twenty patients with suspected burn wound sepsis received either gentamicin or tobramycin. The microbiology of the baseline eschar was determined and repeated on days 2, 4, and 7. All patients had measurable aminoglycoside tissue concentrations, and elimination from serum was not unusually rapid. Thirteen patients had baseline eschar cultures positive for Pseudomonas aeruginosa or Serratia marcescens; eight patients were initially bacteremic. Pseudomonas aeruginosa strains were sensitive to both antibiotics and usually declined in concentration with time or were eliminated; the more drug-resistant isolates of S marcescens persisted or caused super-infection and bacteremia. Aminoglycoside antibiotics penetrate into burn eschar and appear to have a substantial effect on eschar microbiology.

Cutaneous protothecosis. Successful treatment with amphotericin B.

A patient had cutaneous protothecosis because of the alga-like organism, Prototheca wickerhamii. In vitro sensitivity tests showed that the organism was sensitive to amphotericin B, and was treated successfully with this polyene antibiotic. As with treatment of some fungal infections, a clinical response was achieved when therapy with low doses of amphotericin B was given during a short period of time. The basis of the amphotericin B response may have been due to a combination of its immunostimulatory and antibiotic properties.

Comparison of the Vitek GPS-TB card with disk diffusion testing for predicting the susceptibility of enterococci to vancomycin.

OBJECTIVE: To compare the ability of the Vitek GPS-TB card with disk diffusion testing for determining the susceptibility of enterococci to vancomycin. DESIGN: Vitek susceptibility testing was performed using the GPS-TB card and software version R05.03. Disk diffusion susceptibility testing was performed according to National Committee for Clinical Laboratory Standards guidelines. When discrepancies occurred between the interpretation of Vitek and disk diffusion, both tests were repeated and the epsilometer test (E test) and agar screen containing 6 microgram/mL vancomycin were performed. RESULTS: Of 415 isolates tested, 313 were susceptible to vancomycin and 97 were resistant to vancomycin by both test methods. Two isolates were intermediate by Vitek and resistant by disk diffusion, 2 were intermediate by Vitek and susceptible by disk diffusion, and 1 was susceptible by Vitek and intermediate by disk diffusion. All but 1 of these latter 5 isolates (intermediate by Vitek and susceptible by disk diffusion) were available for retesting. On repeat testing, the 2 isolates that were intermediate by Vitek and resistant by disk diffusion were resistant by both methods, the 1 isolate that was intermediate by Vitek and susceptible by disk diffusion was susceptible by both methods, and the isolate that was susceptible by Vitek and intermediate by disk diffusion was also susceptible by both methods. These results were confirmed by E test and agar screen. CONCLUSION: We found the results of the GPS-TB card compared well with disk diffusion. However, isolates with intermediate results by Vitek should be retested using another method, such as the E test.