Gonzalo Bearman

Time to Blood Culture Positivity as a Predictor of Clinical Outcome of Staphylococcus aureus Bloodstream Infection

ABSTRACT Few studies have assessed the time to blood culture positivity as a predictor of clinical outcome in bloodstream infections (BSIs). The purpose of this study was to evaluate the time to positivity (TTP) of blood cultures in patients with Staphylococcus aureus BSIs and to assess its impact on clinical outcome. We performed a historical cohort study with 91 adult patients with S. aureus BSIs. TTP was defined as the time between the start of incubation and the time that the automated alert signal indicating growth in the culture bottle sounded. Patients with BSIs and TTPs of culture of ≤12 h (n = 44) and >12 h (n = 47) were compared. Septic shock occurred in 13.6% of patients with TTPs of ≤12 h and in 8.5% of patients with TTP of >12 h (P = 0.51). A central venous catheter source was more common with a BSI TTP of ≤12 h (P = 0.010). Univariate analysis revealed that a Charlson score of ≥3, the failure of at least one organ (respiratory, cardiovascular, renal, hematologic, or hepatic), infection with methicillin-resistant S. aureus, and TTPs of ≤12 h were associated with death. Age, gender, an APACHE II score of ≥20 at BSI onset, inadequate empirical antibiotic therapy, hospital-acquired bacteremia, and endocarditis were not associated with mortality. Multivariate analysis revealed that independent predictors of hospital mortality were a Charlson score of ≥3 (odds ratio [OR], 14.4; 95% confidence interval [CI], 2.24 to 92.55), infection with methicillin-resistant S. aureus (OR, 9.3; 95% CI, 1.45 to 59.23), and TTPs of ≤12 h (OR, 6.9; 95% CI, 1.07 to 44.66). In this historical cohort study of BSIs due to S. aureus, a TTP of ≤12 h was a predictor of the clinical outcome.

Hospital-acquired Clostridium difficile-associated disease in the intensive care unit setting: epidemiology, clinical course and outcome

BackgroundClostridium difficile-associated disease (CDAD) is a serious nosocomial infection, however few studies have assessed CDAD outcome in the intensive care unit (ICU). We evaluated the epidemiology, clinical course and outcome of hospital-acquired CDAD in the critical care setting.MethodsWe performed a historical cohort study on 58 adults with a positive C. difficile cytotoxin assay result occurring in intensive care units.ResultsSixty-two percent of patients had concurrent infections, 50% of which were bloodstream infections. The most frequently prescribed antimicrobials prior to CDAD were anti-anaerobic agents (60.3%). Septic shock occurred in 32.8% of CDAD patients. The in-hospital mortality was 27.6%. Univariate analysis revealed that SOFA score, at least one organ failure and age were predictors of mortality. Charlson score ≥3, gender, concurrent infection, and number of days with diarrhea before a positive C. difficile toxin assay were not significant predictors of mortality on univariate analysis. Independent predictors for death were SOFA score at infection onset (per 1-point increment, OR 1.40; CI95 1.13–1.75) and age (per 1-year increment, OR 1.10; CI95 1.02–1.19).ConclusionIn ICU patients with CDAD, advanced age and increased severity of illness at the onset of infection, as measured by the SOFA score, are independent predictors of death.

Screening for MRSA: A Flawed Hospital Infection Control Intervention

Focusing hospital resources on a single antibiotic-resistant pathogen as a sole approach to infection control is inherently flawed. We applied attributable mortality principles to a basic model of bloodstream infections to outline the argument. Screening for methicillin-resistant Staphylococcus aureus alone made sense in the 1980s, but the ongoing emergence of vancomycin-resistant enterococci and antibiotic-resistant strains of gram-negative rods and Candida species, as well as the recognition of the value of team-based infection control programs, support a population-based approach.

Bacteremia due to Clostridium difficile - review of the literature.

Extracolonic Clostridium difficile infections have been infrequently reported. Extracolonic manifestations of C. difficile include bacteremia, intra-abdominal abscess, osteomyelitis, visceral abscess, empyema, reactive arthritis, and small bowel disease with formation of pseudomembranes on ileal mucosa. Most cases of extracolonic C. difficile have been preceded by gastrointestinal disease, either C. difficile colitis or surgical and anatomical disruption of the colon. Bacteremia due to C. difficile has previously been described in 14 patients with underlying gastrointestinal processes. We report a unique case of monomicrobial C. difficile bacteremia in a young woman with an underlying hematologic malignancy. The patient lacked gastrointestinal symptoms or radiologic findings suggestive of colitis or ongoing gastrointestinal pathology.

Reconsidering contact precautions for endemic methicillin-resistant staphylococcus aureus and vancomycin-resistant enterococcus

BACKGROUND Whether contact precautions (CP) are required to control the endemic transmission of methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) in acute care hospitals is controversial in light of improvements in hand hygiene, MRSA decolonization, environmental cleaning and disinfection, fomite elimination, and chlorhexidine bathing. OBJECTIVE To provide a framework for decision making around use of CP for endemic MRSA and VRE based on a summary of evidence related to use of CP, including impact on patients and patient care processes, and current practices in use of CP for MRSA and VRE in US hospitals. DESIGN A literature review, a survey of Society for Healthcare Epidemiology of America Research Network members on use of CP, and a detailed examination of the experience of a convenience sample of hospitals not using CP for MRSA or VRE. PARTICIPANTS Hospital epidemiologists and infection prevention experts. RESULTS No high quality data support or reject use of CP for endemic MRSA or VRE. Our survey found more than 90% of responding hospitals currently use CP for MRSA and VRE, but approximately 60% are interested in using CP in a different manner. More than 30 US hospitals do not use CP for control of endemic MRSA or VRE. CONCLUSIONS Higher quality research on the benefits and harms of CP in the control of endemic MRSA and VRE is needed. Until more definitive data are available, the use of CP for endemic MRSA or VRE in acute care hospitals should be guided by local needs and resources.

Accuracy of Screening for Inhalational Anthrax after a Bioterrorist Attack

Context In the event of a bioterrorist attack, it may be difficult to distinguish inhalational anthrax from viral respiratory tract disease. Contribution This synthesis compares reported symptoms of 28 patients with inhalational anthrax and 4694 patients with viral respiratory tract illnesses. Fever and cough were common in both infections. Mental confusion or loss of consciousness, shortness of breath, and nausea and vomiting more often indicated anthrax, whereas sore throat and runny nose more often indicated viral infection. Implications Several symptoms, including neurologic and gastrointestinal symptoms and shortness of breath, may help distinguish inhalational anthrax from respiratory viral illness. The Editors The 2001 anthrax attacks in the United States, in which 11 people developed the inhalational form of the disease and 5 died, exposed a weakness in the U.S. medical response to bioterrorism (1). Despite heroic efforts on behalf of the victims, physicians were largely unprepared to recognize the early symptoms and signs of this extremely rare and rapidly progressive infection in ambulatory patients (2). Initially, 4 of the 11 patients were sent home after being seen as outpatients or in an emergency department with diagnoses that included viral syndrome, bronchitis, and gastroenteritis (3, 4). Physicians first considered a diagnosis of anthrax in 2 of these patients (both postal workers) on their second visits to the emergency department and then only after hearing media reports of illness among other postal employees (3). Inhalation of anthrax spores leads to clinical disease from elaboration of two toxins, a calmodulin-dependent adenylate cyclase known as edema factor and a zinc metalloproteinase called lethal factor, by phagocytosed bacteria in the mediastinal lymph nodes and bloodstream (5). Classic pathologic findings include hemorrhagic mediastinitis and hemorrhagic meningitis; primary anthrax pneumonia is rare (6, 7). Without prompt treatment, death occurs rapidly from a combination of shock and respiratory compromise. Anthrax has been classified by the U.S. Centers for Disease Control and Prevention as one of six category A bioterrorist agents posing the greatest risk to civilian populations (8). A large-scale anthrax attack has the potential to cause casualties on a scale that would quickly overwhelm local and regional health care treatment capacity (6). The emergency response to such an attack would probably include the establishment of multiple mass prophylaxis centers physically distinct from hospital emergency departments (to prevent overcrowding and potential contamination) for rapid dispensing of prophylactic antibiotics to exposed populations and for identifying individuals suspected of having inhalational anthrax (9). Presumptive cases would be transferred to established or temporary medical care facilities for rapid definitive testing and initiation of combination antimicrobial treatment, which may improve outcomes (10-12). Efficient management of this limited medical care capacity is an important secondary goal of outpatient triage during a bioterrorism response (13, 14). Screening and triage protocols used in these settings would need to rely on presenting symptoms and signs because laboratory or radiographic testing will probably not be feasible in high-volume mass prophylaxis centers (15). We sought to establish an evidence base for developing a screening protocol for inhalational anthrax. The utility of such a protocol, which improves both case detection and case exclusion, would also extend beyond the immediate mass prophylaxis setting because large numbers of individuals outside the exposure zone will probably seek reassurance from health care providers for symptomatic illnesses in the aftermath of a major attack. Providing scientific evidence on which to base these discussions may decrease postattack anxiety and inappropriate utilization of health care resources (16). Methods Clinical data on the 11 inhalational anthrax cases of 2001 are now widely available (3, 4, 17-20). Because of the small number of cases in the contemporary attack, we performed a systematic literature review to identify additional original case reports of inhalational anthrax in the English-language medical literature. We searched two computerized databases (MEDLINE and Web of Science) for adult human case reports of anthrax infection between 1960 and 2000 using the keywords anthrax and case report. This yielded 44 references; 4 contained sufficient clinical data on inhalational anthrax to permit comparison with the 11 contemporary cases (21-24). Tracing bibliographies of these articles and a recent review article (25) produced an additional 7 articles that were appropriate for inclusion, for a total of 11 reports on 17 cases (26-32). Two of the cases involved patients from outside of the United States (22, 24). We interpreted lack of mention of a specific symptom or abnormal sign in these reports as indicating the absence of that finding from the patients clinical presentation. We compared proportions of symptoms and signs in historical and contemporary cases using the Fisher exact test; clinical features that had consistent prevalence rates in earlier and contemporary cases were candidates for comparison with viral respiratory tract disease. Viral respiratory tract infections, such as with influenza, respiratory syncytial virus (RSV), parainfluenza, and rhinoviruses or coronaviruses, are appropriate comparison conditions for this study because of their prevalence and potential similarity to inhalational anthrax (15, 33). We searched MEDLINE for descriptive epidemiologic reports of presenting clinical features of laboratory-confirmed influenza and noninfluenza viral respiratory illnesses in ambulatory adults; we found five published studies that met the search criteria (34-38). We did not include studies that describe samples of mixed influenza and noninfluenza cases (39-42) or that present data already reported in these five studies (43). We did not compare anthrax cases with asymptomatic persons (because they would not present a screening dilemma) or with acutely ill patients (because they would probably not participate in mass screening). Since there are no reports of inhalational anthrax in pediatric patients, we limited our comparison sample to adult patients. Finally, we also compared anthrax cases to ambulatory patients with community-acquired pneumonia to highlight the difficulty of distinguishing these two conditions (44). We calculated positive likelihood ratios with 95% CIs for the presence of selected signs and symptoms in inhalational anthrax versus influenza, influenza-like illness, and ambulatory community-acquired pneumonia. The positive likelihood ratio is defined here as the prevalence of a symptom or sign among inhalational anthrax cases divided by the prevalence of the same symptom or sign in the influenza, influenza-like illness, or pneumonia comparison groups. The positive likelihood ratio is the multiplicative factor that increases or decreases the odds of having inhalational anthrax as opposed to one of these comparison diseases, given the presence of a clinical finding (45). Therefore, the post-test probability of having inhalational anthrax is influenced by both the magnitude of the positive likelihood ratio and the pretest probability of having the disease (46). In the appropriate clinical setting (that is, when the pretest probability of having the target disease is not zero), likelihood ratios greater than 3 or less than 0.3 are considered clinically important (47). The general approach used heredeveloping diagnostic algorithms for rare diagnoses by using likelihood ratios and by establishing hypothetical comparison groups populated by common medical conditionshas been previously described (46, 48, 49). The study sponsors had no role in the design, conduct, and reporting of the data or in the decision to submit the manuscript for publication. Results Presenting symptoms and signs and radiographic results for the 11 deliberately infected contemporary cases and 17 occupationally or environmentally infected historical cases were similar, although contemporary patients reported significantly more fever/chills and fatigue or malaise (Table 1). All but 1 of the 28 patients (including 100% of the contemporary patients) had fever, chills, or cough on presentation. (The single exception was a patient who presented with impending shock, which limited the ability to record a complete history.) Other symptoms that affected more than half of all patients included dyspnea (68%), chest discomfort or pain (61%), and nausea or vomiting (61%). More than half of current case-patients and 43% of the combined sample presented with neurologic symptoms other than headache, including confusion, blurred vision, and dizziness. Only a few patients with inhalational anthrax reported sore throat (18%) or rhinorrhea (14%). Table 1. Summary of Symptoms and Signs at Initial Presentation: Historical versus Contemporary Patients with Inhalational Anthrax Eighty-one percent of patients presented with abnormalities on lung auscultation, including rales or rhonchi (65%) and dullness or decreased breath sounds (58%). Respiratory symptoms often did not match findings on lung physical examination. Four of the five patients with no respiratory symptoms had positive findings (rales), whereas 8 of the 23 patients with respiratory symptoms had no abnormality on lung examination. Outcomes differed significantly between historical and contemporary patients: 16 of the 17 historical patients died compared with only 5 of the 11 contemporary patients. The presenting clinical features of the 28 patients can be divided into nine symptom complexes involving respiratory; gastrointestinal; ear, nose, and throat; and nonheadache neurologic problems (Figure 1). The single most common presentation was a combination of respirato

Healthcare Personnel Attire in Non-Operating-Room Settings

Healthcare personnel (HCP) attire is an aspect of the medical profession steeped in culture and tradition. The role of attire in cross-transmission remains poorly established, and until more definitive information exists priority should be placed on evidence-based measures to prevent healthcare-associated infections (HAIs). This article aims to provide general guidance to the medical community regarding HCP attire outside the operating room. In addition to the initial guidance statement, the article has 3 major components: (1) a review and interpretation of the medical literature regarding (a) perceptions of HCP attire (from both HCP and patients) and (b) evidence for contamination of attire and its potential contribution to cross-transmission; (2) a review of hospital policies related to HCP attire, as submitted by members of the Society for Healthcare Epidemiology of America (SHEA) Guidelines Committee; and (3) a survey of SHEA and SHEA Research Network members that assessed both institutional HCP attire policies and perceptions of HCP attire in the cross-transmission of pathogens. Recommendations for HCP attire should attempt to balance professional appearance, comfort, and practicality with the potential role of apparel in the cross-transmission of pathogens. Although the optimal choice of HCP attire for inpatient care remains undefined, we provide recommendations on the use of white coats, neckties, footwear, the bare-below-the-elbows strategy, and laundering. Institutions considering these optional measures should introduce them with a well-organized communication and education effort directed at both HCP and patients. Appropriately designed studies are needed to better define the relationship between HCP attire and HAIs.

A crossover trial of antimicrobial scrubs to reduce methicillin-resistant Staphylococcus aureus burden on healthcare worker apparel.

BACKGROUND The impact of antimicrobial scrubs on healthcare worker (HCW) bacterial burden is unknown. Objective. To determine the effectiveness of antimicrobial scrubs on hand and apparel bacterial burden. DESIGN Prospective, crossover trial. SETTING AND PARTICIPANTS Thirty HCWs randomized to study versus control scrubs in an intensive care unit. METHODS Weekly microbiology samples were obtained from scrub abdominal area, cargo pocket, and hands. Mean log colony-forming unit (CFU) counts were calculated. Compliance with hand hygiene practices was measured. Apparel and hand mean log CFU counts were compared. RESULTS Adherence measures were 78% (910/1,173) for hand hygiene and 82% (223/273) for scrubs. Culture compliance was 67% (306/460). No differences were observed in bacterial hand burden or in HCWs with unique positive scrub cultures. No difference in vancomycin-resistant enterococci (VRE) and gram-negative rod (GNR) burden was observed. A difference in mean log methicillin-resistant Staphylococcus aureus (MRSA) CFU count was found between study and control scrubs for leg cargo pocket (mean log CFUs, 11.84 control scrub vs 6.71 study scrub; [Formula: see text]), abdominal area (mean log CFUs, 11.35 control scrub vs 7.54 study scrub; [Formula: see text]), leg cargo pocket at the beginning of shift (mean log CFUs, 11.96 control scrub vs 4.87 study scrub; [Formula: see text]), and abdominal area pocket at the end of shift (mean log CFUs, 12.14 control scrubs vs 8.22 study scrub; [Formula: see text]). CONCLUSIONS Study scrubs were associated with a 4-7 mean log reduction in MRSA burden but not VRE or GNRs. A prospective trial is needed to measure the impact of antimicrobial impregnated apparel on MRSA transmission rates.

Successful use of alcohol sensor technology to monitor and report hand hygiene compliance.

Nearly two million healthcare-associated infections are estimated to occur annually in the USA, accounting for nearly 100 000 deaths.1 Many of these infections are suspected to be due to poor compliance with hand hygiene and The Joint Commission has included improvement of compliance with hand hygiene in its National Patient Safety Goals since 2004, and has mandated that hospitals measure compliance rates. However, producing valid performance data remains a challenge.2

Mandatory public reporting in the USA: an example to follow?

Increasingly states in the USA are enacting laws mandating reporting and disclosure of hospital-acquired infections (HAIs). The rapid development of legislation has occurred in response to increased coverage of HAIs in the mainstream media coupled with active involvement of consumer advocacy organizations. The transformation of healthcare in the USA into a commodity has fostered a strong role for consumer advocacy to which state legislative bodies have shown willingness to respond.