Risk Factors for Extended-Spectrum ß-lactamase-Producing Enterobacterales Bloodstream Infection Among Solid-Organ Transplant Recipients.

BACKGROUND: Approximately 40% of all Enterobacterales (EB) bloodstream infections (BSIs) among solid organ transplant recipients (SOTRs) are due to extended-spectrum ß-lactamase (ESBL)-producing organisms, but risk factors for such infections remain ill defined in this population. We sought to determine the risk factors for ESBL-EB BSIs among SOTRs. METHODS: A multicenter case-control study was performed. All SOTRs with an EB BSI at the Hospital of the University of Pennsylvania and University of Maryland Medical Center between 1 January 2007 and 30 June 2018 and at The Johns Hopkins Hospital between 1 January 2005 and 31 December 2015 were included. Cases were those with an ESBL-EB BSI. Controls were those with a non-ESBL-EB BSI. Multivariable logistic regression was performed to determine risk factors for ESBL-EB BSI. RESULTS: There were 988 episodes of EB BSI, of which 395 (40%) were due to an ESBL-EB. On multivariable analysis, the independent risk factors for ESBL-EB BSI included: ESBL-EB on prior culture (aOR, 12.75; 95% CI, 3.23-50.33; P < .001), a corticosteroid-containing immunosuppression regimen (aOR 1.30; 95% CI 1.03-1.65; P = .030), acute rejection treated with corticosteroids (aOR 1.18; 95% CI 1.16-1.19; P < .001), and exposure to third-generation cephalosporins (aOR 1.95; 95% CI 1.48-2.57; P < .001), echinocandins (aOR 1.61; 95% CI 1.08-2.40; P = .020), and trimethoprim-sulfamethoxazole (aOR 1.35; 95% CI 1.10-1.64; P = .003). CONCLUSIONS: We identified several novel risk factors that are uniquely important to the SOTR population, including exposure to trimethoprim-sulfamethoxazole and corticosteroid-containing immunosuppressive regimens. Further studies exploring these associations and testing interventions aimed at these modifiable risk factors among SOTRs are needed.

A Multicenter Evaluation of Probiotic Use for the Primary Prevention of Clostridioides difficile Infection.

BACKGROUND: Primary prevention of Clostridioides difficile infection (CDI) is a priority for hospitals. Probiotics have the potential to interfere with colonization and CDI. In this study, we evaluated the impact of a computerized clinical decision support (CCDS) tool to prescribe probiotics for primary prevention of CDI among adult hospitalized patients. METHODS: A CCDS tool was implemented into the electronic medical record at 4 hospitals to prompt prescription of a probiotic preparation at the time of antibiotic prescription in high-risk patients in May 2019. Interrupted time series using segmented regression analysis was conducted to evaluate hospital-wide CDI incidence for the year pre- and post-CCDS implementation. In addition, multivariable logistic regression was used to evaluate CDI incidence in patients who qualified for probiotics in the pre- vs post-intervention periods, adjusting for potential confounders. To adjust for potential differences in patients who received probiotics in the post-intervention period, propensity score-matched pairs were developed to evaluate CDI risk by receipt of probiotics. RESULTS: Quarterly CDI incidence increased over time post-intervention relative to baseline trends (slope change, 1.4; 95% confidence interval [CI], .9-1.9). The odds ratio (OR) of CDI was 1.41 in eligible patients post-intervention compared with pre-intervention (adjusted OR, 1.41; 95% CI, 1.11-1.79). Propensity score-matched analysis showed that patients who received probiotics did not have lower rates of CDI compared with those who did not receive probiotics (OR, 1.46; 95% CI, .87-2.45). CONCLUSIONS: Use of probiotics for primary prevention of CDI among adult inpatients receiving antibiotics is not supported.

Clinical prediction tool for extended-spectrum beta-lactamase-producing enterobacterales as the etiology of a bloodstream infection in solid organ transplant recipients.

BACKGROUND: Multidrug-resistant Gram-negative bacterial infections are increasingly common among solid organ transplant (SOT) recipients, leading to challenges in the selection of empiric antimicrobial therapy. We sought to develop a clinical tool to predict which SOT recipients are at high risk for extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (EB) bloodstream infection (BSI). METHODS: A multicenter case-control study was performed. The source population included SOT recipients with an EB BSI between 2005 and 2018. Cases were those with ESBL-EB BSI; controls were those with non-ESBL EB BSI. The population was subdivided into derivation and validation cohorts based on study site. The predictive tool was developed in the derivation cohort through iterative multivariable logistic regression analyses that maximized the area under the receiver-operating curve (AUC). External validity was assessed using the validation cohort. RESULTS: A total of 897 SOT recipients with an EB BSI were included, of which 539 were assigned to the derivation cohort (135, 25% ESBL-EB) and 358 to the validation cohort (221, 62% ESBL-EB). Using multivariable analyses, the most parsimonious model that was predictive of ESBL-EB BSI consisted of 10 variables, which fell into four clinical categories: prior colonization or infection with EB organisms, recent antimicrobial exposures, severity of preceding illness, and immunosuppressive regimen. This model achieved an AUC of 0.81 in the derivation cohort and 0.68 in the validation cohort. CONCLUSIONS: Though further refinements are needed in additional populations, this tool shows promise for guiding empiric therapy for SOT recipients with EB BSI.

Impact of a Prescriber-driven Antibiotic Time-out on Antibiotic Use in Hospitalized Patients.

A multicenter quasi-experimental study of a provider-driven antibiotic "time-out" in 3470 antibiotic courses showed no difference in antibiotic use before and after implementation, but did show a decrease in inappropriate therapy (45% vs 31%, P < .05). Single time-outs without input from antibiotic stewardship teams are insufficient to optimize prescribing.

Patient-to-Patient Transmission of Acinetobacter baumannii Gastrointestinal Colonization in the Intensive Care Unit.

Acinetobacter baumannii is an important nosocomial pathogen. The objective of this study was to determine the proportion of A. baumannii infections due to patient-to-patient transmission by analyzing the molecular epidemiology of patients who acquired A. baumannii, using perianal surveillance cultures in a large 2-year intensive care unit (ICU) population. The design was a prospective cohort study. Patients who were admitted to the medical and surgical intensive care units at the University of Maryland Medical Center from 2011 to 2013 underwent admission, weekly, and discharge perianal culture collection. Using multilocus sequence typing (MLST) with subsequent pulsed-field gel electrophoresis (PFGE) for increased discrimination, combined with hospital overlap, the number of patients that acquired A. baumannii due to patient-to-patient transmission was determined. Our cohort consisted of 3,452 patients. In total, 196 cohort patients were colonized with A. baumannii; 130 patients were positive at ICU admission, and 66 patients acquired A. baumannii during their stay. Among the 196 A. baumannii patient isolates, there were 91 unique MLST types. Among the 66 patients who acquired A. baumannii, 31 (50%) were considered genetically related by MLST and/or PFGE type, and 11 (17%) were considered patient-to-patient transmission by genetic relatedness and overlapping hospital stay. Our data show that, of those cases of A. baumannii acquisition, at least 17% were cases of patient-to-patient transmission.

Pharmacodynamic Target Attainment for Cefepime, Meropenem, and Piperacillin-Tazobactam Using a Pharmacokinetic/Pharmacodynamic-Based Dosing Calculator in Critically Ill Patients.

This was a prospective study to determine if pharmacokinetic/pharmacodynamic (PK/PD)-based antibiotic dosing software aids in achieving concentration targets in critically ill patients receiving cefepime (n = 10), meropenem (n = 20), or piperacillin-tazobactam (n = 19). Antibiotic calculator doses targeting a >90% probability of target attainment (PTA) differed from package insert doses for 22.4% (11/49) of patients. Target attainment was achieved for 98% of patients (48/49). A PK/PD-based antibiotic dosing calculator provides beta-lactam doses with a high PTA in critically ill patients.

Risk Factors and Outcomes Associated with Multidrug-Resistant Acinetobacter baumannii upon Intensive Care Unit Admission.

Multidrug-resistant (MDR) Acinetobacter baumannii, associated with broad-spectrum antibiotic use, is an important nosocomial pathogen associated with morbidity and mortality. This study aimed to investigate the prevalence of MDR A. baumannii perirectal colonization among adult patients upon admission to the intensive care unit (ICU) over a 5-year period and to identify risk factors and outcomes associated with colonization. A retrospective cohort analysis of patients admitted to the medical intensive care unit (MICU) and surgical intensive care unit (SICU) at the University of Maryland Medical Center from May 2005 to September 2009 was performed using perirectal surveillance cultures on admission. Poisson and logistic models were performed to identify associated risk factors and outcomes. Four percent of the cohort were positive for MDR A. baumannii at ICU admission. Among patients admitted to the MICU, those positive for MDR A. baumannii at admission were more likely to be older, to have received antibiotics before ICU admission, and to have shorter length of stay in the hospital prior to ICU admission. Among patients admitted to the SICU, those colonized were more likely to have at least one previous admission to our hospital. Patients positive for MDR A. baumannii at ICU admission were 15.2 times more likely to develop a subsequent positive clinical culture for A. baumannii and 1.4 times more likely to die during the current hospitalization. Risk factors associated with MDR A. baumannii colonization differ by ICU type. Colonization acts as a marker of disease severity and of risk of developing a subsequent Acinetobacter infection and of dying during hospitalization. Therefore, active surveillance could guide empirical antibiotic selection and inform infection control practices.

Carbapenem MICs in Escherichia coli and Klebsiella Species Producing Extended-Spectrum ß-Lactamases in Critical Care Patients from 2001 to 2009.

Extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae strains are increasing in prevalence worldwide. Carbapenem antibiotics are used as a first line of therapy against ESBL-producing Enterobacteriaceae We examined a cohort of critical care patients for gastrointestinal colonization with carbapenem-resistant ESBL-producing strains (CR-ESBL strains). We cultured samples from this cohort of patients for ESBL-producing Klebsiella spp. and Escherichia coli and then tested the first isolate from each patient for susceptibility to imipenem, doripenem, meropenem, and ertapenem. Multilocus sequence typing was performed on isolates that produced an ESBL and that were carbapenem resistant. Among all patients admitted to an intensive care unit (ICU), 4% were positive for an ESBL-producing isolate and 0.64% were positive for a CR-ESBL strain on surveillance culture. Among the first ESBL-producing E. coli and Klebsiella isolates from the patients' surveillance cultures, 11.2% were carbapenem resistant. Sequence type 14 (ST14), ST15, ST42, and ST258 were the dominant sequence types detected in this cohort of patients, with ST15 and ST258 steadily increasing in prevalence from 2006 to 2009. Patients colonized by a CR-ESBL strain were significantly more likely to receive antipseudomonal and anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) therapy prior to ICU admission than patients colonized by carbapenem-susceptible ESBL-producing strains. They were also significantly more likely to have received a cephalosporin or a carbapenem antibiotic than patients colonized by carbapenem-susceptible ESBL-producing strains. In conclusion, in a cohort of patients residing in intensive care units within the United States, we found that 10% of the isolates were resistant to at least one carbapenem antibiotic. The continued emergence of carbapenem-resistant ESBL-producing strains is of significant concern, as infections due to these organisms are notoriously difficult to treat.

Factors Leading to Transmission Risk of Acinetobacter baumannii.

OBJECTIVES: To identify patient and healthcare worker factors associated with transmission risk of Acinetobacter baumannii during patient care. DESIGN: Prospective cohort study. SETTING: ICUs at a tertiary care medical center. PATIENTS: Adult ICU patients known to be infected or colonized with A. baumannii. MEASUREMENTS AND MAIN RESULTS: Cultures of skin, respiratory tract, and the perianal area were obtained from participants and evaluated for the presence of A. baumannii. Healthcare worker-patient interactions were observed (up to five interactions/patient) and activities were recorded. Healthcare worker hands/gloves were sampled at room exit (prior to hand hygiene or glove removal) and then evaluated for the presence of A. baumannii. Two hundred fifty-four healthcare worker-patient interactions were observed among 52 patients; A. baumannii was identified from healthcare worker hands or gloves in 77 (30%) interactions. In multivariate analysis, multidrug-resistant A. baumannii (odds ratio, 4.78; 95% CI, 2.14-18.45) and specific healthcare worker activities (touching the bed rail [odds ratio, 2.19; 95% CI, 1.00-4.82], performing a wound dressing [odds ratio, 8.35; 95% CI, 2.07-33.63] and interacting with the endotracheal tube or tracheotomy site [odds ratio, 5.15; 95% CI, 2.10-12.60]), were associated with hand/glove contamination. CONCLUSIONS: Healthcare worker hands/gloves are frequently contaminated with A. baumannii after patient care. Patient-level factors were not associated with an increased transmission risk; however, having multidrug-resistant-A. baumannii and specific healthcare worker activities led to an increased contamination risk. Our findings reveal a potential selective advantage possessed by multidrug-resistant-A. baumannii in this environment and suggest possible areas for future research.

Advancing interprofessional patient safety education for medical, nursing, and pharmacy learners during clinical rotations.

Clinical errors are common and can lead to adverse events and patient death. Health professionals must work within interprofessional teams to provide safe and effective care to patients, yet current curricula is lacking with regards to interprofessional education and patient safety. We describe the development and implementation of an interprofessional course aimed at medical, nursing, and pharmacy learners during their clinical training at a large academic medical centre. The course objectives were based on core competencies for interprofessional education and patient safety. The course was offered as recurring three 1-hour sessions, including case-based discussions and a mock root cause analysis. Forty-three students attended at least one session over a 7-month period. We performed a cross-sectional survey of participants to assess readiness for interprofessional learning and a before and after comparison of patient safety knowledge. All students reported a high level of readiness for interprofessional learning, indicating an interest in interprofessional opportunities. In general, understanding and knowledge of the four competency domains in patient safety was low before the course and 100% of students reported an increase in knowledge in these domains after participating in the course.

Alcohol-based decontamination of gloved hands: A randomized controlled trial.

OBJECTIVE: The gold standard for hand hygiene (HH) while wearing gloves requires removing gloves, performing HH, and donning new gloves between WHO moments. The novel strategy of applying alcohol-based hand rub (ABHR) directly to gloved hands might be effective and efficient. DESIGN: A mixed-method, multicenter, 3-arm, randomized trial. SETTING: Adult and pediatric medical-surgical, intermediate, and intensive care units at 4 hospitals. PARTICIPANTS: Healthcare personnel (HCP). INTERVENTIONS: HCP were randomized to 3 groups: ABHR applied directly to gloved hands, the current standard, or usual care. METHODS: Gloved hands were sampled via direct imprint. Gold-standard and usual-care arms were compared with the ABHR intervention. RESULTS: Bacteria were identified on gloved hands after 432 (67.4%) of 641 observations in the gold-standard arm versus 548 (82.8%) of 662 observations in the intervention arm (P < .01). HH required a mean of 14 seconds in the intervention and a mean of 28.7 seconds in the gold-standard arm (P < .01). Bacteria were identified on gloved hands after 133 (98.5%) of 135 observations in the usual-care arm versus 173 (76.6%) of 226 observations in the intervention arm (P < .01). Of 331 gloves tested 6 (1.8%) were found to have microperforations; all were identified in the intervention arm [6 (2.9%) of 205]. CONCLUSIONS: Compared with usual care, contamination of gloved hands was significantly reduced by applying ABHR directly to gloved hands but statistically higher than the gold standard. Given time savings and microbiological benefit over usual care and lack of feasibility of adhering to the gold standard, the Centers for Disease Control and Prevention and the World Health Organization should consider advising HCP to decontaminate gloved hands with ABHR when HH moments arise during single-patient encounters.Trial Registration: NCT03445676.

Factors associated with patient-to-healthcare personnel (HCP) and HCP-to-subsequent patient transmission of methicillin-resistant Staphylococcus aureus.

BACKGROUND: Transient acquisition of methicillin-resistant Staphylococcus aureus (MRSA) on healthcare personnel (HCP) gloves and gowns following patient care has been examined. However, the potential for transmission to the subsequent patient has not been studied. We explored the frequency of MRSA transmission from patient to HCP, and then in separate encounters from contaminated HCP gloves and gowns to a subsequent simulated patient as well as the factors associated with these 2 transmission pathways. METHODS: We conducted a prospective cohort study with 2 parts. In objective 1, we studied MRSA transmission from random MRSA-positive patients to HCP gloves and gowns after specific routine patient care activities. In objective 2, we simulated subsequent transmission from random HCP gloves and gowns without hand hygiene to the next patient using a manikin proxy. RESULTS: For the first objective, among 98 MRSA-positive patients with 333 randomly selected individual patient-HCP interactions, HCP gloves or gowns were contaminated in 54 interactions (16.2%). In a multivariable analysis, performing endotracheal tube care had the greatest odds of glove or gown contamination (OR, 4.06; 95% CI, 1.3-12.6 relative to physical examination). For the second objective, after 147 simulated HCP-patient interactions, the subsequent transmission of MRSA to the manikin proxy occurred 15 times (10.2%). CONCLUSION: After caring for a patient with MRSA, contamination of HCP gloves and gown and transmission to subsequent patients following HCP-patient interactions occurs frequently if contact precautions are not used. Proper infection control practices, including the use of gloves and gown, can prevent this potential subsequent transmission.

Infection prevention in the cancer center.

Cancer patients are frequently immunosuppressed and at risk for a wide range of opportunistic and healthcare-associated infections. A good infection prevention program is extremely important to reduce risk of infection. This review focuses on infection prevention measures specific to patients, healthcare personnel, and visitors in the cancer center.

Molecular concordance of methicillin-resistant Staphylococcus aureus isolates from healthcare workers and patients.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a significant nosocomial pathogen in the ICU. MRSA contamination of healthcare personnel (HCP) gloves and gowns after providing care to patients with MRSA occurs at a rate of 14%-16% in the ICU setting. Little is known about whether the MRSA isolates identified on HCP gown and gloves following patient care activities are the same as MRSA isolates identified as colonizing or infecting the patient. METHODS: From a multisite cohort of 388 independent patient MRSA isolates and their corresponding HCP gown and glove isolates, we selected 91 isolates pairs using a probability to proportion size (PPS) sampling method. To determine whether the patient and HCP gown or gloves isolates were genetically similar, we used 5 comparative genomic typing methods: phylogenetic analysis, spa typing, multilocus sequence typing (MLST), large-scale BLAST score ratio (LSBSR), and single-nucleotide variant (SNV) analysis. RESULTS: We identified that 56 (61.5%) of isolate pairs were genetically similar at least by 4 of the methods. Comparably, the spa typing and the LSBSR analyses revealed that >75% of the examined isolate pairs were concordant, with the thresholds established for each analysis. CONCLUSIONS: Many of the patient MRSA isolates were genetically similar to those on the HCP gown or gloves following a patient care activity. This finding indicates that the patient is often the primary source of the MRSA isolates transmitted to the HCP, which can potentially be spread to other patients or hospital settings through HCP vectors. These results have important implications because they provide additional evidence for hospitals considering ending the use of contact precautions (gloves and gowns) for MRSA patients.

Clinical Outcomes and Risk Factors for Carbapenem-resistant Enterobacterales Bloodstream Infection in Solid Organ Transplant Recipients.

BACKGROUND: The clinical outcomes associated with, and risk factors for, carbapenem-resistant Enterobacterales (CRE) bloodstream infections (BSIs) in solid organ transplant (SOT) recipients remain ill-defined. METHODS: A multicenter retrospective cohort study was performed, including SOT recipients with an Enterobacterales BSI between 2005 and 2018. Exposed subjects were those with a CRE BSI. Unexposed subjects were those with a non-CRE BSI. A multivariable survival analysis was performed to determine the association between CRE BSI and risk of all-cause mortality within 60 d. Multivariable logistic regression analysis was performed to determine independent risk factors for CRE BSI. RESULTS: Of 897 cases of Enterobacterales BSI in SOT recipients, 70 (8%) were due to CRE. On multivariable analysis, CRE BSI was associated with a significantly increased hazard of all-cause mortality (adjusted hazard ratio, 2.85; 95% confidence interval [CI], 1.68-4.84; P < 0.001). Independent risk factors for CRE BSI included prior CRE colonization or infection (adjusted odds ratio [aOR] 9.86; 95% CI, 4.88-19.93; P < 0.001)' liver transplantation (aOR, 2.64; 95% CI, 1.23-5.65; P = 0.012)' lung transplantation (aOR, 3.76; 95% CI, 1.40-10.09; P = 0.009)' and exposure to a third-generation cephalosporin (aOR, 2.21; 95% CI, 1.17-4.17; P = 0.015) or carbapenem (aOR, 2.80; 95% CI, 1.54-5.10; P = 0.001) in the prior 6 months. CONCLUSIONS: CRE BSI is associated with significantly worse outcomes than more antibiotic-susceptible Enterobacterales BSI in SOT recipients.

Direct Gloving vs Hand Hygiene Before Donning Gloves in Adherence to Hospital Infection Control Practices: A Cluster Randomized Clinical Trial.

Importance: Current guidelines require hand hygiene before donning nonsterile gloves, but evidence to support this requirement is lacking. Objective: To evaluate the effectiveness of a direct-gloving policy on adherence to infection prevention practices in a hospital setting. Design, Setting, and Participants: This mixed-method, multicenter, cluster randomized clinical trial was conducted at 4 academic centers in Baltimore, Maryland, or Iowa City, Iowa, from January 1, 2016, to November 30, 2017. Data analysis was completed April 25, 2019. Participants were 3790 health care personnel (HCP) across 13 hospital units. Intervention: Hospital units were randomly assigned to direct gloving, with hand hygiene not required before donning gloves (intervention), or to usual care (hand hygiene before donning nonsterile gloves). Main Outcomes and Measures: The primary outcome was adherence to the expected practice at room entry and exit. A random sample of HCPs' gloved hands were imprinted on agar plates at entry to contact precautions rooms. The intention-to-treat approach was followed, and all analyses were conducted at the level of the participating unit. Primary and secondary outcomes between treatment groups were assessed using generalized estimating equations with an unstructured working correlation matrix to adjust for clustering; multivariate analysis using generalized estimating equations was conducted to adjust for covariates, including baseline adherence. Results: In total, 13 hospital units participated in the trial, and 3790 HCP were observed. Adherence to expected practice was greater in the 6 units with the direct-gloving intervention than in the 7 usual care units (1297 of 1491 [87%] vs 954 of 2299 [41%]; P < .001) even when controlling for baseline hand hygiene rates, unit type, and universal gloving policies (risk ratio [RR], 1.76; 95% CI, 1.58-1.97). Glove use on entry to contact precautions rooms was also higher in the direct-gloving units (1297 of 1491 [87%] vs 1530 of 2299 [67%]; P = .008. The intervention had no effect on hand hygiene adherence measured at entry to non-contact precautions rooms (951 of 1315 [72%] for usual care vs 1111 of 1688 [66%] for direct gloving; RR, 1.00 [95% CI, 0.91-1.10]) or at room exit (1587 of 1897 [84%] for usual care vs 1525 of 1785 [85%] for direct gloving; RR, 0.98 [95% CI, 0.91-1.07]). The intervention was associated with increased total bacteria colony counts (adjusted incidence RR, 7.13; 95% CI, 3.95-12.85) and greater detection of pathogenic bacteria (adjusted incidence RR, 10.18; 95% CI, 2.13-44.94) on gloves in the emergency department and reduced colony counts in pediatrics units (adjusted incidence RR, 0.34; 95% CI, 0.19-0.63), with no change in either total colony count (RR, 0.87 [95% CI, 0.60 to 1.25] for adult intensive care unit; RR, 0.59 [95% CI, 0.31-1.10] for hemodialysis unit) or presence of pathogenic bacteria (RR, 0.93 [95% CI, 0.40-2.14] for adult intensive care unit; RR, 0.55 [95% CI, 0.15-2.04] for hemodialysis unit) in the other units. Conclusions and Relevance: Current guidelines require hand hygiene before donning nonsterile gloves, but evidence to support this requirement is lacking. The findings from this cluster randomized clinical trial indicate that a direct-gloving strategy without prior hand hygiene should be considered by health care facilities. Trial Registration: ClinicalTrials.gov Identifier: NCT03119389.

Comparison of swab and sponge methodologies for identification of Acinetobacter baumannii from the hospital environment.

The ideal sampling method for identification of Acinetobacter baumannii from the health care environment is unknown. In this study, we sampled 145 surfaces in the rooms of patients with known A. baumannii colonization/infection, comparing two methods: swab and sponge. The sensitivity of the swab method was 87%, while the sensitivity of the sponge method was 75%. Given the comparable results, use of the cheaper and less laborious swab technique is acceptable and may be preferable.

Transfer of multidrug-resistant bacteria to healthcare workers' gloves and gowns after patient contact increases with environmental contamination.

OBJECTIVE: To assess the role of environmental contamination in the transmission of multidrug-resistant bacteria to healthcare workers' clothing. DESIGN: Prospective cohort. SETTING: Six intensive care units at a tertiary care hospital. SUBJECTS: Healthcare workers including registered nurses, patient care technicians, respiratory therapists, occupational/physical therapists, and physicians. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: One hundred twenty of 585 (20.5%) healthcare worker/patient interactions resulted in contamination of healthcare workers' gloves or gowns. Multidrug-resistant Acinetobacter baumannii contamination occurred most frequently, 55 of 167 observations (32.9%; 95% confidence interval [CI] 25.8% to 40.0%), followed by multidrug-resistant Pseudomonas aeruginosa, 15 of 86 (17.4%; 95% CI 9.4% to 25.4%), vancomycin-resistant Enterococcus, 25 of 180 (13.9%, 95% CI 8.9, 18.9%) and methicillin-resistant Staphylococcus aureus, 21 of 152 (13.8%; 95% CI 8.3% to 19.2%). Independent risk factors associated with healthcare worker contamination with multidrug-resistant bacteria were positive environmental cultures (odds ratio [OR] 4.2; 95% CI 2.7-6.5), duration in room for >5 mins (OR 2.0; 95% CI 1.2-3.4), performing physical examinations (OR 1.7; 95% CI 1.1-2.8), and contact with the ventilator (OR 1.8; 95% CI, 1.1-2.8). Pulsed field gel electrophoresis determined that 91% of healthcare worker isolates were related to an environmental or patient isolate. CONCLUSIONS: The contamination of healthcare workers' protective clothing during routine care of patients with multidrug-resistant organisms is most frequent with A. baumannii. Environmental contamination was the major determinant of transmission to healthcare workers' gloves or gowns. Compliance with contact precautions and more aggressive environmental cleaning may decrease transmission.

Genomic comparison of multi-drug resistant invasive and colonizing Acinetobacter baumannii isolated from diverse human body sites reveals genomic plasticity.

BACKGROUND: Acinetobacter baumannii has recently emerged as a significant global pathogen, with a surprisingly rapid acquisition of antibiotic resistance and spread within hospitals and health care institutions. This study examines the genomic content of three A. baumannii strains isolated from distinct body sites. Isolates from blood, peri-anal, and wound sources were examined in an attempt to identify genetic features that could be correlated to each isolation source. RESULTS: Pulsed-field gel electrophoresis, multi-locus sequence typing and antibiotic resistance profiles demonstrated genotypic and phenotypic variation. Each isolate was sequenced to high-quality draft status, which allowed for comparative genomic analyses with existing A. baumannii genomes. A high resolution, whole genome alignment method detailed the phylogenetic relationships of sequenced A. baumannii and found no correlation between phylogeny and body site of isolation. This method identified genomic regions unique to both those isolates found on the surface of the skin or in wounds, termed colonization isolates, and those identified from body fluids, termed invasive isolates; these regions may play a role in the pathogenesis and spread of this important pathogen. A PCR-based screen of 74 A. baumanii isolates demonstrated that these unique genes are not exclusive to either phenotype or isolation source; however, a conserved genomic region exclusive to all sequenced A. baumannii was identified and verified. CONCLUSIONS: The results of the comparative genome analysis and PCR assay show that A. baumannii is a diverse and genomically variable pathogen that appears to have the potential to cause a range of human disease regardless of the isolation source.

Increased mortality with accessory gene regulator (agr) dysfunction in Staphylococcus aureus among bacteremic patients.

Accessory gene regulator (agr) dysfunction in Staphylococcus aureus has been associated with a longer duration of bacteremia. We aimed to assess the independent association between agr dysfunction in S. aureus bacteremia and 30-day in-hospital mortality. This retrospective cohort study included all adult inpatients with S. aureus bacteremia admitted between 1 January 2003 and 30 June 2007. Severity of illness prior to culture collection was measured using the modified acute physiology score (APS). agr dysfunction in S. aureus was identified semiquantitatively by using a δ-hemolysin production assay. Cox proportional hazard models were used to measure the association between agr dysfunction and 30-day in-hospital mortality, statistically adjusting for patient and pathogen characteristics. Among 814 patient admissions complicated by S. aureus bacteremia, 181 (22%) patients were infected with S. aureus isolates with agr dysfunction. Overall, 18% of patients with agr dysfunction in S. aureus died, compared to 12% of those with functional agr in S. aureus (P = 0.03). There was a trend toward higher mortality among patients with S. aureus with agr dysfunction (adjusted hazard ratio [HR], 1.34; 95% confidence interval [CI], 0.87 to 2.06). Among patients with the highest APS (scores of >28), agr dysfunction in S. aureus was significantly associated with mortality (adjusted HR, 1.82; 95% CI, 1.03 to 3.21). This is the first study to demonstrate an independent association between agr dysfunction and mortality among severely ill patients. The δ-hemolysin assay examining agr function may be a simple and inexpensive approach to predicting patient outcomes and potentially optimizing antibiotic therapy.