Dennis G. Maki

A semiquantitative culture method for identifying intravenous-catheter-related infection.

We evaluated a semiquantitative culture technic for identifying infection due to intravenous catheters: rolling the catheter segment across blood agar. This method was compared to broth culture. Of 250 catheters studied, 225 (90%) had low-density colonization on semiquantitative culture (less than 15 colonies on the plate) although 49 (19.6%) of these grew some organisms in broth or on the plate. None of these catheters led to septicemia. Twenty-five catheters (10%) grew greater than or equal to 15 colonies by the semiquantitative technic; most gave confluent growth. Septicemia originated from four of these catheters (P = 0.008). Of 37 catheters exposed to bacteremias from distant foci of infection, four yielded matching growth in broth, whereas none were concordant with the blood isolate on semiquantitative culture. Local inflammation was associated with high-density colonization semiquantitative culture (P less than 0.001). The semiquantitative technic distinguishes infection (greater than or equal to 15 colonies) from contamination and is more specific in diagnosis of catheter-related septicemia than culture of the catheter in broth.

The risk of bloodstream infection in adults with different intravascular devices: a systematic review of 200 published prospective studies.

OBJECTIVE To better understand the absolute and relative risks of bloodstream Infection (BSI) associated with the various types of intravascular devices (IVDs), we analyzed 200 published studies of adults In which every device in the study population was prospectively evaluated for evidence of associated infection and microbiologically based criteria were used to define IVD-related BSI. METHODS English-language reports of prospective studies of adults published between January 1, 1966, and July 1, 2005, were identified by MEDLINE search using the following general search strategy: bacteremla [Medical Subject Heading, MeSH] OR septicemia [MeSH] OR bloodstream Infection AND the specific type of intravascular device (e.g., central venous port). Mean rates of IVD-related BSI were calculated from pooled data for each type of device and expressed as BSIs per 100 IVDs (%) and per 1000 IVD days. RESULTS Point incidence rates of IVD-related BSI were lowest with peripheral Intravenous catheters (0.1%, 0.5 per 1000 IVD-days) and midline catheters (0.4%, 0.2 per 1000 catheter-days). Far higher rates were seen with short-term noncuffed and nonmedicated central venous catheters (CVCs) (4.4%, 2.7 per 1000 catheter-days). Arterial catheters used for hemodynamic monitoring (0.8%, 1.7 per 1000 catheter-days) and peripherally inserted central catheters used in hospitalized patients (2.4%, 2.1 per 1000 catheter-days) posed risks approaching those seen with short-term conventional CVCs used in the Intensive care unit. Surgically implanted long-term central venous devices--cuffed and tunneled catheters (22.5%, 1.6 per 1000 IVD-days) and central venous ports (3.6%, 0.1 per 1000 IVD-days)--appear to have high rates of Infection when risk Is expressed as BSIs per 100 IVDs but actually pose much lower risk when rates are expressed per 1000 IVD-days. The use of cuffed and tunneled dual lumen CVCs rather than noncuffed, nontunneled catheters for temporary hemodlalysis and novel preventive technologies, such as CVCs with anti-infective surfaces, was associated with considerably lower rates of catheter-related BSI. CONCLUSIONS Expressing risk of IVD-related BSI per 1000 IVD-days rather than BSIs per 100 IVDs allows for more meaningful estimates of risk. These data, based on prospective studies In which every IVD in the study cohort was analyzed for evidence of infection by microbiologically based criteria, show that all types of IVDs pose a risk of IVD-related BSI and can be used for benchmarking rates of infection caused by the various types of IVDs In use at the present time. Since almost all the national effort and progress to date to reduce the risk of IVD-related Infection have focused on short-term noncuffed CVCs used in Intensive care units, Infection control programs must now strive to consistently apply essential control measures and preventive technologies with all types of IVDs.

The Safety and Efficacy of Daptomycin for the Treatment of Complicated Skin and Skin-Structure Infections

Daptomycin is the first available agent from a new class of antibiotics, the cyclic lipopeptides, that has activity against a broad range of gram-positive pathogens, including organisms that are resistant to methicillin, vancomycin, and other currently available agents. Daptomycin (4 mg/kg intravenously [iv] every 24 h for 7-14 days) was compared with conventional antibiotics (penicillinase-resistant penicillins [4-12 g iv per day] or vancomycin [1 g iv every 12 h]) in 2 randomized, international trials involving 1092 patients with complicated skin and skin-structure infections. Among 902 clinically evaluable patients, clinical success rates were 83.4% and 84.2% for the daptomycin- and comparator-treated groups, respectively (95% confidence interval, -4.0 to 5.6). Among patients successfully treated with iv daptomycin, 63% required only 4-7 days of therapy, compared with 33% of comparator-treated patients (P<.0001). The frequency and distribution of adverse events were similar among both treatment groups. Overall, the safety and efficacy of daptomycin were comparable with conventional therapy.

Infection Control in Intravenous Therapy

Abstract The intravenous infusion has become indispensable in modern medical therapy, but infection, especially infusion-associated septicemia, remains a life-threatening hazard. In 1970 to 1971 a ...

The pathogenesis and epidemiology of catheter-related infection with pulmonary artery Swan-Ganz catheters: A prospective study utilizing molecular subtyping

To delineate the pathogenesis and epidemiology of catheter-related infection with Swan-Ganz pulmonary artery (PA) catheters, a prospective clinical study of hospitalized adult medical and surgical patients was done. Role of catheter material was assessed by randomizing insertions to heparin-bonded PA catheters made of polyvinylchloride or polyurethane. Sources of infection and pathogenesis were studied by culturing skin, the introducer, the PA catheter tip, all hubs, infusate from each lumen, and the extravascular portion of the PA catheter beneath the external protective plastic sleeve. Concordance between isolates from sources and infected catheters was determined by speciation, antibiogram, and for coagulase-negative staphylococci, plasmid profile analysis. Risk factors for infection were determined by stepwise logistic regression. Overall, 65 (22%) of 297 Swan-Ganz catheters showed local infection of the introducer (58 catheters) or the intravascular portion of the PA catheter (20 catheters); only two catheters (0.7%) caused bacteremia. Eighty percent of infected Swan-Ganz catheters (the introducer or PA catheter) showed concordance with organisms cultured from skin of the insertion site, 17% with a contaminated hub and 18% with organisms contaminating the extravascular portion of the PA catheter beneath the sleeve. Isolates from infected PA catheters were most likely to show concordance with concomitantly infected introducers (71%). Cutaneous colonization of the insertion site with greater than 10(2) cfu/10 cm2 (relative risk [RR] 5.5; p less than 0.001), insertion into an internal jugular vein (RR 4.3; p less than 0.01), catheterization greater than 3 days (RR 3.1; p less than 0.01), and insertion in the operating room using less stringent barrier precautions (RR 2.1; p = 0.03) were each associated with a significantly increased risk of catheter-related infection. The risk of bacteremic infection with Swan-Ganz catheters is now low, in the range of 1%, with reasonable care. Swan-Ganz catheters are vulnerable to contamination from multiple sources, but the patients skin is the single most important source of organisms causing invasive infection, which in most cases involves the introducer rather than the PA catheter. Heavy colonization of the insertion site, percutaneous insertion in the internal jugular vein rather than subclavian vein, catheterization longer than 3 days, and insertion with less stringent barrier precautions significantly increase the risk of catheter-related infection. These findings hold promise for application to management of Swan-Ganz catheters and research in catheter design to reduce the risk of catheter-related infection.

An attachable silver-impregnated cuff for prevention of infection with central venous catheters: A prospective randomized multicenter trial

PURPOSE Percutaneously inserted central venous catheters are widely used. Catheter-related bacteremia or fungemia is the most frequent serious complication of these catheters. In an attempt to reduce the frequency of such infections, a subcutaneous cuff constructed of a biodegradable collagen matrix impregnated with bactericidal silver was developed. Our goal was to assess, in a multicenter clinical trial, the effectiveness of this cuff in preventing catheter-related infection. MATERIALS AND METHODS Central venous catheters needed for fluid or drug therapy, hemodynamic monitoring, or hyperalimentation in patients in three centers were randomly assigned to be inserted with or without the cuff. Patients and catheters in the two groups were comparable in terms of risk factors predisposing to infection, including colonization of skin about the insertion site. RESULTS The results with 234 catheters inserted into a new site showed that catheters inserted with the cuff were threefold less likely to be colonized on removal (more than 15 colony-forming units) than were control catheters (28.9 percent versus 9.1 percent, p = 0.002) and were nearly fourfold less likely to produce bacteremia (3.7 percent versus 1.0 percent). Adverse effects from the cuff were not seen. The cuff did not confer protection, however against infection with catheters inserted over a guidewire into old sites. Most of the catheter-related infections identified in this study, including four of the six bacteremias, appear to have been caused by microorganisms colonizing skin about the insertion site, affirming the pathogenetic basis for benefit seen with the cuff in this clinical trial; two may have derived from contamination of the catheter hub. CONCLUSION This novel, silver-impregnated, attachable cuff can substantially reduce the incidence of catheter-related infection with most percutaneously inserted central venous catheters, can extend the time catheters can be left in place safely, and can prove cost-beneficial.

Intravascular catheter-related infections: advances in diagnosis, prevention, and management

Indwelling vascular catheters are a leading source of bloodstream infections in critically ill patients and cancer patients. Because clinical diagnostic criteria are either insensitive or non-specific, such infections are often overdiagnosed, resulting in unnecessary and wasteful removal of the catheter. Catheter-sparing diagnostic methods, such as differential quantitative blood cultures and time to positivity have emerged as reliable diagnostic techniques. Novel preventive strategies include cutaneous antisepsis, maximum sterile barrier, use of antimicrobial catheters, and antimicrobial catheter lock solution. Management of catheter-related bloodstream infections involves deciding on catheter removal, antimicrobial catheter lock solution, and the type and duration of systemic antimicrobial therapy. Such decisions depend on the identity of the organism causing the bloodstream infection, the clinical and radiographical manifestations suggesting a complicated course, the underlying condition of the host (neutropenia, thrombocytopenia), and the availability of other vascular access sites.

Risk Factors for Infusion-related Phlebitis with Small Peripheral Venous Catheters: A Randomized Controlled Trial

OBJECTIVE To identify risk factors for infusion-related phlebitis with peripheral intravenous catheters. DESIGN A randomized trial of two catheter materials, with consideration of 21 potential risk factors. SETTING A university hospital. PATIENTS Hospitalized adults without granulocytopenia who received a peripheral intravenous catheter. INTERVENTIONS House officers or ward nurses inserted the catheters, and each insertion was randomized to a catheter made of tetrafluoroethylene-hexafluoropropylene (FEP-Teflon) or a novel polyetherurethane without leachable additives (PEU-Vialon). MEASUREMENTS Research nurses scored insertion sites each day for inflammation and cultured catheters at removal. RESULTS The Kaplan-Meier risk for phlebitis exceeded 50% by day 4 after catheterization. intravenous antibiotics (relative risk, 2.00), female sex (relative risk, 1.88), prolonged (greater than 48 hours) catheterization (relative risk, 1.79), and catheter material (PEU-Vialon: FEP-Teflon) (relative risk, 0.73) strongly predicted phlebitis in a Cox proportional hazards model (each, P less than 0.003). The best-fit model for severe phlebitis identified the same predictors plus catheter-related infection (relative risk, 6.19), phlebitis with a previous catheter (relative risk, 1.54), and anatomic site (hand: forearm, relative risk, 0.71; wrist:forearm, relative risk, 0.60). The low incidence of local catheter-related infection was comparable with the two catheter materials (5.4% [95% CI, 3.8% to 7.6%] and 6.9% [CI, 4.9% to 9.6%]); none of the 1054 catheters prospectively studied caused bacteremia. CONCLUSIONS Multiple factors, including the infusate and the duration of cannulation, contribute to the development of infusion-related phlebitis. The use of peripheral intravenous catheters made of PEU-Vialon appears to pose the same risk for catheter-related infection as the use of catheters made of FEP-Teflon, and PEU-Vialon can permit longer cannulation with less risk for phlebitis. The risk for catheter-related bacteremia with FEP-Teflon and PEU-Vialon catheters is sufficiently low that it no longer seems justifiable to recommend the use of small steel needles for most peripheral intravenous therapy.

Guidelines for the prevention of intravascular catheter-related infections.

BACKGROUND Although many catheter-related bloodstream infections (CRBSIs) are preventable, measures to reduce these infections are not uniformly implemented. OBJECTIVE To update an existing evidenced-based guideline that promotes strategies to prevent CRBSIs. DATA SOURCES The MEDLINE database, conference proceedings, and bibliographies of review articles and book chapters were searched for relevant articles. STUDIES INCLUDED Laboratory-based studies, controlled clinical trials, prospective interventional trials, and epidemiologic investigations. OUTCOME MEASURES Reduction in CRBSI, catheter colonization, or catheter-related infection. SYNTHESIS The recommended preventive strategies with the strongest supportive evidence are education and training of healthcare providers who insert and maintain catheters; maximal sterile barrier precautions during central venous catheter insertion; use of a 2% chlorhexidine preparation for skin antisepsis; no routine replacement of central venous catheters for prevention of infection; and use of antiseptic/antibiotic-impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies (ie, education and training, maximal sterile barrier precautions, and 2% chlorhexidine for skin antisepsis). CONCLUSION Successful implementation of these evidence-based interventions can reduce the risk for serious catheter-related infection.

Device-Associated Nosocomial Infections in 55 Intensive Care Units of 8 Developing Countries

Context We know little about medical deviceassociated infections in developing countries. Contribution Prospective surveillance of 21069 patients who were hospitalized in 55 intensive care units in 46 hospitals in Central and South America, India, Morocco, and Turkey showed high rates (22.5 infections per 1000 intensive care unit days) of device-associated infections. Infections included ventilator-associated pneumonia (24.1 cases/1000 ventilator days), central venous catheterrelated bloodstream infections (12.5 cases/1000 catheter days), and catheter-associated urinary tract infections (8.9 cases/1000 catheter days). Eighty-four percent of Staphylococcus aureus infections were caused by methicillin-resistant strains, 51% of Enterobacteriaceae isolates were ceftriaxone-resistant, and 59% of Pseudomonas aeruginosa isolates were fluoroquinolone-resistant. Implications Medical deviceassociated infections pose major risks in developing countries. The Editors Surveillance of health careassociated infections, especially in high-risk hospital settings, such as the intensive care unit (ICU) (1, 2), has become an integral feature of infection control and quality assurance in all U.S. hospitals. The Centers for Disease Control and Prevention (CDC) Study of the Efficacy of Nosocomial Infection Control (SENIC) Project (3) showed that surveillance can help prevent health careassociated infections. Standards for institutional surveillance have been adopted in the United States (1), the United Kingdom (4), Australia (5), Canada (6), and Germany (7). A growing body of literature has shown that health careassociated infections are a major cause of patient illness and death in developed countries (8, 9). Device-associated infections, particularly ventilator-associated pneumonia (1012), central venous catheter (CVC)associated bloodstream infections (1315), and catheter-associated urinary tract infections (16, 17), pose the greatest threat to patient safety in the ICU (18). Surveillance of health careassociated infection has been standardized by the CDCs National Nosocomial Infection Surveillance (NNIS) System by providing simple unambiguous definitions, especially for device-associated infections (1921). Targeted surveillance and calculation of device-associated infection rates per 1000 device days allows benchmarking with similar other hospitals and detection of unique institutional problems that need redress. Most published studies of ICU-acquired infections have come from hospitals in industrialized western countries (1, 8, 1019, 22, 23). Relatively few data have been reported from developing countries (9, 2427), especially rates of device-associated infections by using standardized definitions. We report the initial findings of an International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2002 through December 2005. The consortium was established by Dr. Rosenthal in 1998 when selected hospitals in Latin America began collecting surveillance data on health careassociated infections for inclusion in a regional database. Consortium hospitals provide general medical and surgical inpatient services to adults and children who require short-term care. All data from the participating hospitals were collected by using standardized NNIS System protocols and definitions (1921). The consortium has initially focused on surveillance and prevention of device-associated infections in adult and pediatric ICUs and high-risk nurseries. Methods Setting Most current participating hospitals and ICUs joined the consortium since 2002 after hearing Dr. Rosenthal (the INICC chairman) speak in their country or after learning about the INICC from its Web site (www.inicc.org), but some hospitals were actively solicited. Study data were collected between 2002 and 2005 in 55 ICUs in 46 hospitals from 8 developing countries: Argentina, Brazil, Colombia, India, Mexico, Morocco, Peru, and Turkey. The consortium requires each member hospital to have an infection control team, comprising a physician and an infection control practitioner, and a microbiology laboratory that can isolate and identify aerobic pathogens from clinical cultures and perform in vitro susceptibility testing by using standardized methods (28). The person responsible for surveillance in each institution must have had at least 3 years of infection control experience (Table 1). In most of the hospitals, the team had access to electronic patient data. Table 1. Features of the International Nosocomial Infection Control Consortium Hospitals and Intensive Care Units* The institutional review board at each hospital approved the study protocol. Patient confidentiality is protected by coding the recorded information, with patient identities available only to the individual hospitals infection control team. Infection Control Practices at the Study Sites Hand hygiene adherence varies in the different countries and ICUs, ranging from 20% to 70% (2932). A recent study in all participating ICUs found a 50% overall rate of hand hygiene adherence (32), similar to that of recent studies in the United States and Europe (33). Use of sterile dressings on CVC insertion sites also ranges widely (29, 34, 35). Open infusion systems (rigid or semirigid containers that must admit air to empty) rather than closed systems (fully collapsible containers that do not require any external vent to empty the solution; the container residue after administration does not exceed 5% of the nominal volume) or combinations of open and closed systems are universally used to deliver intravenous fluids and medications in the study hospitals (35). Surveillance and Case Report Forms Each center established an augmented infection control program, with the initial major emphasis on active surveillance of health careassociated infections and process surveillance of hand hygiene adherence and invasive device care. During the study, we determined the rates of ventilator-associated pneumonia, CVC-associated bloodstream infection, and catheter-associated urinary tract infection monthly by using current CDC NNIS System definitions (1921). Designated surveillance forms were used for all patients in the study ICUs, both patients with and those without health careassociated infection. The following data were to be recorded daily on the forms for each patient: temperature and blood pressure, invasive devices, all cultures done, imaging studies, and antibiotic use. Previous studies have shown that fever, hypotension, cultures, and initiation of antimicrobial therapy are powerful markers for the presence of a health careassociated infection (36). A mean average severity of illness score was also recorded for each patient at ICU admission by using the CDC NNIS System criteria (19). Points were totaled, with 1 point for surgical patients who require routine postoperative observation only, 2 points for physiologically stable nonsurgical patients who require overnight observation, 3 points for patients who need continuous nursing care and monitoring, 4 points for physiologically unstable patients who require intensive nursing and medical care and need frequent reassessment and adjustment of therapy, and 5 points for physiologically unstable patients who are in a coma or in shock and require cardiopulmonary resuscitation or intensive medical and nursing care with frequent reassessment. If a patient was determined to have acquired a health careassociated infection, the date of onset, site of infection, infecting microorganisms, and antimicrobial susceptibilities were also recorded. Definitions Ventilator-Associated Pneumonia Ventilator-associated pneumonia is indicated in a mechanically ventilated patient with a chest radiograph that shows new or progressive infiltrates, consolidation, cavitation, or pleural effusion. The patient must also have at least 1 of the following criteria: new onset of purulent sputum or change in character of sputum; organism cultured from blood; or isolation of an etiologic agent from a specimen obtained by tracheal aspirate, bronchial brushing or bronchoalveolar lavage, or biopsy. Laboratory-Confirmed CVC-Associated Bloodstream Infection Central venous catheterassociated bloodstream infection is laboratory-confirmed when a patient with a CVC has a recognized pathogen that is isolated from 1 or more percutaneous blood cultures after 48 hours of vascular catheterization and is not related to an infection at another site. The patient also has at least 1 of the following signs or symptoms: fever (temperature 38C), chills, or hypotension. With skin commensals (for example, diphtheroids, Bacillus spp., Propionibacterium spp., coagulase-negative staphylococci, or micrococci), the organism is cultured from 2 or more blood cultures. Clinically Suspected CVC-Associated Bloodstream Infection Central venous catheterassociated bloodstream infection is clinically suspected when a patient with a CVC has at least 1 of the following clinical signs with no other identified cause: fever (temperature 38C), hypotension (systolic blood pressure 90 mm Hg), or oliguria (urine output 20 mL/h) with blood cultures not obtained or no organisms recovered from blood cultures, infections not apparent at another site, and antimicrobial therapy instituted by the physician. Catheter-Associated Urinary Tract Infection For the diagnosis of catheter-associated urinary tract infection, the patient must meet 1 of 2 criteria. The first criterion is when a patient with a urinary catheter has 1 or more of the following symptoms with no other recognized cause: fever (temperature 38C), urgency, or suprapubic tenderness when the urine culture is positive for 105 colony-forming units per mL or more, with no more than 2 microorganisms isolated. The second criterion is when a patient with a urinary catheter has at least 2 of the following criteria with no other recognized cause: positive dipstick analysis for leukocyte esterase or nitr