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Objective:In the era of widespread resistance, there are 2 time points at which most empiric prescription errors occur among hospitalized adults: (1) upon admission (UA) when treating patients at risk of multidrug-resistant organisms (MDROs) and (2) during hospitalization, when treating patients at risk of extensively drug-resistant organisms (XDROs). These errors adversely influence patient outcomes and the hospital’s ecology.Design and setting:Retrospective cohort study, Shamir Medical Center, Israel, 2016.Patients:Adult patients (aged >18 years) hospitalized with sepsis.Methods:Logistic regressions were used to develop predictive models for (1) MDRO UA and (2) nosocomial XDRO. Their performances on the derivation data sets, and on 7 other validation data sets, were assessed using the area under the receiver operating characteristic curve (ROC AUC).Results:In total, 4,114 patients were included: 2,472 patients with sepsis UA and 1,642 with nosocomial sepsis. The MDRO UA score included 10 parameters, and with a cutoff of ≥22 points, it had an ROC AUC of 0.85. The nosocomial XDRO score included 7 parameters, and with a cutoff of ≥36 points, it had an ROC AUC of 0.87. The range of ROC AUCs for the validation data sets was 0.7–0.88 for the MDRO UA score and was 0.66–0.75 for nosocomial XDRO score. We created a free web calculator (https://assafharofe.azurewebsites.net).Conclusions:A simple electronic calculator could aid with empiric prescription during an encounter with a septic patient. Future implementation studies are needed to evaluate its utility in improving patient outcomes and in reducing overall resistances.

Introduction Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli infections have become endemic worldwide. We aimed to describe the molecular and clinical epidemiology of ESBL-producing E. coli infections during a period of rising global prevalence. Methods Three hundred sixty-nine consecutive ESBL-producing E. coli infections in Detroit from 2010–2011 were analyzed. Sequence typing (ST) and CH typing were performed. Clinical characteristics and outcomes were compared between patients infected with ST131 and non-ST131 isolates. Results Ninety-six percent of isolates were ST 131, and 78.6% of ST 131 isolates produced blaCTX-M-15. Median time to effective therapy was 48 h vs. 35 h (P = 0.38) in the ST131 vs. non-ST131 groups. Ninety-day mortality rates (8% vs. 8%, P = 1.0) were similar between the two groups. Conclusion blaCTX-M-15 ST131 E. coli predominated in Detroit during an early period of global ST131 dissemination. Patients with ST131 E. coli infections had similar clinical outcomes to those with non-ST131 E. coli infections. Electronic supplementary material The online version of this article (10.1007/s40121-020-00321-6) contains supplementary material, which is available to authorized users.

Hospital-acquired urinary tract infections (HAUTI) are common and most cases are related to catheters (CAUTI). HAUTI and CAUTI surveillance is mandatory in many countries as a measure to reduce the incidence of infections and appropriately direct the allocation of preventable resources. The surveillance criteria issued by the Israeli Ministry of Health (IMOH), differ somewhat from that of the U.S. Centers for Disease Control and Prevention (CDC). Our study aims were to query and quantify the impact of these differences. In a retrospective cohort study conducted at Shamir Medical Center, for calendar year 2017, the surveillance criteria of both IMOH and CDC were applied on 644 patient-unique adults with “positive” urine cultures (per similar definitions). The incidence of HAUTI per IMOH was significantly higher compared to CDC (1.24/1000 vs. 1.02/1000 patient-days, p = 0.02), with no impact on hospitalization’s outcomes. The agreement rate between methods was high for CAUTI (92%), but much lower for all HAUTI (83%). The major error rate, i.e., patients diagnosed with HAUTI per IMOH but had no UTI per CDC, was 31%. To conclude, in order for surveillance to reflect the relative situation and direct allocation of preventable resources based on scientific literature, the process should be uniform worldwide.

Aim: Recent guidelines recommended removing metronidazole as a therapeutic option for Clostridioides difficile infections (CDI). However, superiority of vancomycin over metronidazole in mild CDI is not established and use of vancomycin might lead to emergence of vancomycin-resistant enterococci (VRE). Patients & methods: A retrospective cohort study and efficacy analyses were conducted at Shamir Medical Center, Israel (2010–2015), among adults with acute CDI. Results: A total of 409 patients were enrolled. In multivariable analyses, metronidazole was noninferior to vancomycin for mild CDI, but vancomycin was an independent predictor for post-CDI VRE acquisition. Conclusion: A significant independent association was evident between treatment with vancomycin and, later, acquisition of VRE. In first episodes of mild acute CDI, metronidazole should be considered a valid therapeutic option.

Background Studying hospital outbreaks by using molecular tools, i.e. synthesizing the molecular epidemiology data to its appropriate clinical-epidemiologic context, is crucial in order to identify infection source, infer transmission dynamics, appropriately allocate prevention resources and implement control measures. Whole-genome sequencing (WGS) of pathogens has become the reference standard, as it is becoming more accessible and affordable. Consequently, sequencing of the full pathogen genome via WGS and major progress in fit-for-purpose genomic data analysis tools and interpretation is revolutionizing the field of outbreak investigations in hospitals. Metagenomics is an additional evolving field that might become commonly used in the future for outbreak investigations. Nevertheless, practitioners are frequently limited in terms of WGS or metagenomics, especially for local outbreak analyses, as a result of costs or logistical considerations, reduced or lack of locally available resources and/or expertise. As a result, traditional approaches, including pulsed-field gel electrophoresis, repetitive-element palindromic PCR and multilocus sequence typing, along with other typing methods, are still widely used. Aims To provide practitioners with evidenced-based action plans for usage of the various typing techniques in order to investigate the molecular epidemiology of nosocomial outbreaks, of clinically significant pathogens in acute-care hospitals. Sources PubMed search with relevant keywords along with personal collection of relevant publications. Content Representative case scenarios and critical review of the relevant scientific literature. Implications The review provides practical action plans to manage molecular epidemiologic investigations of outbreaks caused by clinically significant nosocomial pathogens, while prioritizing the use and timely integration of the various methodologies.

Background Consensus guidelines caution against colistin (COL) monotherapy due to efficacy and resistance development concerns. The COL + meropenem (MEM) combination often displays in vitro synergy against carbapenem-resistant (CR) Gram-negative bacilli (GNB). We recently completed a clinical trial comparing outcomes in patients receiving COL vs. COL + MEM. Herein we assess if, amongst patients receiving COL + MEM, outcomes differed as a function of the presence (or absence) of in vitro synergy against the index pathogen. Methods OVERCOME was an international, multicenter, randomized, double-blind, placebo-controlled study comparing COL + placebo and COL + MEM for the treatment of pneumonia and/or bloodstream infection (BSI) due to CR GNB. Baseline isolates were COL susceptible (MIC ≤ 2 mg/L) and underwent synergy testing to COL + MEM in 24-hour time kill experiments (TKE). Synergy was defined as a >2-log CFU/ml reduction with combination therapy compared to the most active single agent. Outcomes assessed included 28-day mortality, clinical failure, and the development of COL resistance (MIC ≥ 4 mg/L) for both the overall cohort and the subgroup with A. baumannii. Results Of the 211 patients who received COL + MEM in OVERCOME, 186 had baseline synergy testing performed and were eligible for this analysis. The median age of the cohort was 70 years, 35% were female, 48% were white, and 44% Asian. Sixty-eight percent were in the intensive care unit (ICU) at infection onset. A. baumannii was the most common pathogen (78%) and pneumonia was the most common infection (68%). Synergy was demonstrated in most isolates (76%). Baseline characteristics, clinical, and microbiological outcomes were similar amongst patients infected with isolates against which COL + MEM demonstrated synergy and those where no synergy was demonstrated (Table 1). In patients with A. baumannii infections, the presence of in vitro synergy was associated with a decrease in clinical failure (53% vs. 79%; p = 0.04). No significant impact of synergy on 28-day mortality or development of COL resistance was demonstrated (Table 2). Conclusion The presence of in vitro synergy via TKE was associated with a decrease in clinical failure in patients treated with COL + MEM for invasive infections due to CR A. baumannii. Disclosures Jason M Pogue, PharmD, BCPS, BCIDP, Merck (Consultant)QPex (Consultant)Shionogi (Consultant)Utility Therapeutics (Consultant)VenatoRX (Consultant) Michael J. Rybak, PharmD, MPH, PhD, Paratek Pharmaceuticals (Research Grant or Support) Emmanuel Roilides, MD, PhD, FIDSA, FAAM, FESCMID, Merck Sharp & Dohme Corp. (Consultant, Grant/Research Support) Matthew Sims, MD, PhD, Astra Zeneca (Independent Contractor)Diasorin Molecular (Independent Contractor)Epigenomics Inc (Independent Contractor)Finch (Independent Contractor)Genentech (Independent Contractor)Janssen Pharmaceuticals NV (Independent Contractor)Kinevant Sciences gmBH (Independent Contractor)Leonard-Meron Biosciences (Independent Contractor)Merck and Co (Independent Contractor)OpGen (Independent Contractor)Prenosis (Independent Contractor)Regeneron Pharmaceuticals Inc (Independent Contractor)Seres Therapeutics Inc (Independent Contractor)Shire (Independent Contractor)Summit Therapeutics (Independent Contractor)

In human medicine, infections caused by third-generation cephalosporin-resistant Enterobacterales (3GCRE) are associated with detrimental outcomes. In veterinary medicine, controlled epidemiological analyses are lacking. A matched case–case–control investigation (1:1:1 ratio) was conducted in a large veterinary hospital (2017–2019). In total, 29 infected horses and donkeys were matched to 29 animals with third-generation cephalosporin-susceptible Enterobacterales (3GCSE) infections, and 29 uninfected controls (overall n = 87). Despite multiple significant associations per bivariable analyses, the only independent predictor for 3GCRE infection was recent exposure to antibiotics (adjusted odds ratio (aOR) = 104, p &lt, 0.001), but this was also an independent predictor for 3GCSE infection (aOR = 22, p &lt, 0.001), though the correlation with 3GCRE was significantly stronger (aOR = 9.3, p = 0.04). In separated multivariable outcome models, 3GCRE infections were independently associated with reduced clinical cure rates (aOR = 6.84, p = 0.003) and with 90 days mortality (aOR = 3.6, p = 0.003). Klebsiella spp. were the most common 3GCRE (36%), and blaCTX-M-1 was the major β-lactamase (79%). Polyclonality and multiple sequence types were evident among all Enterobacterales (e.g., Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae). The study substantiates the significance of 3GCRE infections in equine medicine, and their independent detrimental impact on cure rates and mortality. Multiple Enterobacterales genera, subtypes, clones and mechanisms of resistance are prevalent among horses and donkeys with 3GCRE infections.

Background Risk factors and outcomes associated with carbapenem-resistant Enterobacteriaceae (CRE) acquisitions are derived primarily from cohorts consisting of carbapenemase-producing (CP) strains. Worldwide epidemiology of non-CP-CRE is evolving, but controlled epidemiological analyses are lacking. Methods A matched case-case-control investigation was conducted at Shamir (Assaf Harofeh) Medical Center, Israel, on November 2014–December 2016. Noncarbapenemase-producing CRE (as defined by the US Clinical and Laboratory Standards Institute Standards) carriers were matched to patients with non-CRE Enterobacterales and to uninfected controls (1:1:1 ratio). Matched and nonmatched multivariable regression models were constructed to analyze predictors for acquisition and the independent impact of carriage on multiple outcomes, respectively. Representative isolates were whole genome sequenced and analyzed for resistome and phylogeny. Results Noncarbapenemase-producing CRE carriers (n = 109) were matched to the 2 comparative groups (overall n = 327). Recent exposure to antibiotics (but not specifically to carbapenems), prior intensive care unit admission, and chronic skin ulcers were all independent predictors for non-CP-CRE acquisition. Acquisitions were almost exclusively associated with asymptomatic carriage (n = 104), and despite strong associations per univariable analyses, none were independently associated with worse outcomes. Genomic analyses of 13 representative isolates revealed polyclonality, confirmed the absence of carbapenemases, but confirmed the coexistence of multiple other genes contributing to carbapenem-resistance phenotype (multiple beta-lactamases and efflux pumps). Conclusions Noncarbapenemase-producing CRE acquisitions are primarily associated with asymptomatic carriage, specifically among prone populations with extensive recent exposures to antibiotics. The prevalent mode of acquisition is “emergence of resistance” (not “patient-to-patient transmission”), and therefore the role of stewardship interventions in reducing the spread of these therapeutically challenging pathogens should be further explored.

Objectives We aimed to compare the prevalence of asymptomatic coronavirus disease 19 (COVID-19) among clinical staff in designated COVID-19 units versus that among staff in similar units with no known or suspected COVID-19 patients. Methods We conducted a cross-sectional survey of healthcare workers (HCWs) in eight Israeli general hospitals. The survey involved a questionnaire and a PCR test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We surveyed HCWs in COVID-19 units and comparison units (internal medicine and cardiology) between 30th April and 7th May 2020. Results There were 522 participants: 291 from COVID-19 units and 231 from comparison units. Only one participant (0.2%, 95%CI: 0.005–1.1%)—an asymptomatic nurse on a COVID-19 unit—tested positive for SARS-CoV-2. In participating COVID-19 units there were two symptomatic HCWs with confirmed COVID-19 in the 2 weeks before the survey; both were infected by contact with a co-worker outside of the COVID-19 unit. Conclusions The low prevalence of asymptomatic COVID-19 among HCWs, coupled with an absence of symptomatic COVID-19 acquired during patient care, suggest that Israel's national guidelines for personal protective equipment, which are consistent with those of the World Health Organization, adequately protect HCWs.

Background Risk factors and outcomes associated with carbapenem-resistant Enterobacteriaceae (CRE) acquisitions are derived primarily from cohorts consisting of carbapenemase-producing (CP) strains. Worldwide epidemiology of non-CP-CRE is evolving, but controlled epidemiological analyses are lacking. Methods A matched case-case-control investigation was conducted at Shamir (Assaf Harofeh) Medical Center, Israel, on November 2014–December 2016. Noncarbapenemase-producing CRE (as defined by the US Clinical and Laboratory Standards Institute Standards) carriers were matched to patients with non-CRE Enterobacterales and to uninfected controls (1:1:1 ratio). Matched and nonmatched multivariable regression models were constructed to analyze predictors for acquisition and the independent impact of carriage on multiple outcomes, respectively. Representative isolates were whole genome sequenced and analyzed for resistome and phylogeny. Results Noncarbapenemase-producing CRE carriers (n = 109) were matched to the 2 comparative groups (overall n = 327). Recent exposure to antibiotics (but not specifically to carbapenems), prior intensive care unit admission, and chronic skin ulcers were all independent predictors for non-CP-CRE acquisition. Acquisitions were almost exclusively associated with asymptomatic carriage (n = 104), and despite strong associations per univariable analyses, none were independently associated with worse outcomes. Genomic analyses of 13 representative isolates revealed polyclonality, confirmed the absence of carbapenemases, but confirmed the coexistence of multiple other genes contributing to carbapenem-resistance phenotype (multiple beta-lactamases and efflux pumps). Conclusions Noncarbapenemase-producing CRE acquisitions are primarily associated with asymptomatic carriage, specifically among prone populations with extensive recent exposures to antibiotics. The prevalent mode of acquisition is “emergence of resistance” (not “patient-to-patient transmission”), and therefore the role of stewardship interventions in reducing the spread of these therapeutically challenging pathogens should be further explored., In case-case-control matched analyses, exposure to antibiotics was a modifiable independent predictor for non-CP-CRE acquisition, whereas genomic analyses revealed strains’ polyclonality. Therefore, the role of stewardship interventions in curbing the continued spread of non-CP-CRE in hospitals should be further explored.

Background Basins used for patient bathing have been shown to be contaminated with multidrug-resistant organisms (MDROs) and have prompted the evaluation of alternatives to soap and water bathing methods. Methods We conducted a prospective, randomized, open-label interventional crossover study to assess the impact of replacing traditional bath basins with prepackaged washcloths on the incidence of hospital-associated infections (HAIs), MDROs, and secondarily, rates of skin deterioration. Unit-wide use of disposable washcloths over an 8-month period was compared with an 8-month period of standard care using basins. Results A total of 2,637 patients were included from 2 medical-surgical units at a single tertiary medical center, contributing 16,034 patient days. During the study period, there were a total of 33 unit-acquired infections, the rates of which were not statistically different between study phases (incidence rate ratio, 1.05; 95% confidence interval [CI], 0.50-2.23; P = .88). However, occurrence of skin integrity deterioration was significantly less in the intervention group (odds ratio, 0.44; 95% CI, 0.22-0.88; P = .02). Conclusions Although we were unable to demonstrate a significant reduction in HAI or MDRO acquisition, we found a decrease in skin deterioration with the use of disposable washcloths and confirmed earlier findings of MDRO contamination of wash basins.

Background: Many septic patients are receiving empirical antipseudomonal (or Gram-negative non-glucose fermenting [GNNGF]) coverage on admission to acute care hospitals, despite the fact that the indications are not scientifically established. Overuse of antipseudomonals might contribute to the burden of resistance. Materials and methods: Retrospective observational analyses of the characteristics of septic adult patients who received empirical antipseudomonals, along with its impact on outcomes, were executed at Shamir Medical Center, Zerifin, Israel (08–12/2016). Proper empirical antipseudomonal usage was defined by the following: (1) if the patient received the agents as per Infectious Disease Society of America (IDSA) guidelines; (2) if the patient had a positive multidrug-resistant organism (MDRO) test on his or her admission score (https://assafharofe.azurewebsites.net); or (3) if a GNNGF was the eventual causative pathogen. Risk factors and outcomes were queried by logistic and Cox regression. Results: GNNGF was the causative pathogen in only 57 (3.7%) of 1536 patients with acute sepsis. There were 192 (13%) who received empirical antipseudomonals, of whom 161 (84%) were defined as proper. Patients who received empirical antipseudomonals were significantly older (P < 0.001), with higher indices of chronic and acute conditions, and higher rates of past MDRO carriage; 24 patients received empirical antipseudomonals only because of IDSA guidelines (15%), and that was an independent predictor for later acquisition (up to 90 days) of carbapenem-resistant A. baumannii (CRAB; odds ratio [aOR] = 7.1; P = 0.03). Conclusions: Improper empirical usage of antipseudomonals in acute care hospitals is common. Instituting empirical antipseudomonals solely due to IDSA guidelines was independently associated with later acquisition of CRAB. Empirical antipseudomonal usage should be based on scientifically established prediction tools and not on IDSA guidelines.

The global spread of carbapenem-resistant Enterobacteriaceae (CRE) has been fostered by the lack of preemptive screening of patients in healthcare facilities that could prevent patient-to-patient transmission. Outbreaks of CRE infections have led some institutions to implement rigorous screening programs, although controlled comparative data are frequently lacking. Resource limitations and uncertainty regarding the optimal approach has kept many facilities from enacting more active routine surveillance policies that could reduce the prevalence of CRE. The ideal population to target for screening, the frequency of testing, and the preferred test method are components of surveillance programs that remain open to debate. This review discusses the rationale for different screening policies in use and the performance characteristics of laboratory methods available to detect CRE carriage.

Carbapenems are considered the treatment of choice for Acinetobacter baumannii infections. Many facilities implement preventive measures toward only carbapenem-resistant A. baumannii (CRAB). However, the independent role of the carbapenem resistance determinant on patient outcomes remains controversial. In a 6-year analysis of adults with A. baumannii bloodstream infection (BSI), the outcomes of 149 CRAB isolates were compared to those of 91 patients with carbapenem-susceptible A. baumannii . In bivariable analyses, CRAB BSIs were significantly associated with worse outcomes and with a delay in the initiation of appropriate antimicrobial therapy (DAAT). However, in multivariable analyses, carbapenem resistance status was no longer associated with poor outcomes, while DAAT remained an independent predictor. The epidemiological significance of A. baumannii should not be determined by its resistance to carbapenems.

Background Health care–associated infection (HcAI) is a term frequently used to describe community-onset infections likely to be caused by multidrug-resistant organisms (MDROs). The most frequently used definition was developed at Duke University Medical Center in 2002 (Duke-2002). Although some professional societies have based management recommendations on Duke-2002 (or modifications thereof), neither Duke-2002 nor other variations have had their performance measured. Methods A case–control study was conducted at Assaf Harofeh Medical Center (AHMC) of consecutive adult bloodstream infections (BSIs). A multivariable model was used to develop a prediction score for HcAI, measured by the presence of MDRO infection on admission. The performances of this new score and previously developed definitions at predicting MDRO infection on admission were measured. Results Of the 504 BSI patients enrolled, 315 had a BSI on admission and 189 had a nosocomial BSI. Patients with MDRO-BSI on admission (n = 100) resembled patients with nosocomial infections (n = 189) in terms of epidemiological characteristics, illness acuity, and outcomes more than patients with non-MDRO-BSI on admission (n = 215). The performances of both the newly developed score and the Duke-2002 definition to predict MDRO infection on admission were suboptimal (area under the receiver operating characteric curve, 0.76 and 0.68, respectively). Conclusions Although the term HcAI is frequently used, its definition does not perform well at predicting MDRO infection present on admission to the hospital. A validated score that calculates the risk of MDRO infection on admission is still needed to guide daily practice and improve patient outcomes.

It is unknown as to whether other beta-lactams can be used for bloodstream infections (BSI) resulting from Pseudomonas aeruginosa (PA) which are non-susceptible to one or more carbapenem. We conducted a retrospective cohort study at the Assaf Harofeh Medical Center (AHMC) from January 2010 to August 2014. Adult patients with PA-BSI non-susceptible to a group 2 carbapenem but susceptible to ceftazidime or piperacillin (with or without tazobactam), were enrolled. We compared the outcomes of patients who received an appropriate beta-lactam antibiotic (“cases”) to those who received an appropriate non-beta-lactam antibiotic (“controls”). Whole genome sequencing was performed for one of the isolates. Twenty-six patients with PA-BSI met inclusion criteria: 18 received a beta-lactam and 8 a non-beta-lactam (three a fluoroquinolone, two colistin, one a fluoroquinolone and an aminoglycoside, one a fluoroquinolone and colistin, and one colistin and an aminoglycoside). All clinical outcomes were similar between the groups. There were large variations in the phenotypic susceptibilities of the strains. A detailed molecular investigation of one isolate revealed a strain that belonged to MLST-137, with the presence of multiple efflux pumps, OXA-50, and a chromosomally mediated Pseudomonas-derived cephalosporinase (PDC). The oprD gene was intact. Non-carbapenem-β-lactams may still be effective alternatives for short duration therapy (up to 14 days) for BSI caused by a carbapenem non-susceptible (but susceptible to ceftazidime, piperacillin, and/or piperacillin-tazobactam) PA strain. This observation requires further confirmatory analyses. Future molecular investigations should be performed, in order to further analyze additional potential mechanisms for this prevalent phenotype.

Aim: The transmission dynamics of Acinetobacter baumannii in endemic settings, and the relation between microbial properties and patients’ clinical outcomes, are yet obscure and hampered by insufficient metadata. Methods & Results: Of 20 consecutive patients with A. baumannii bloodstream infection that were thoroughly analyzed at a single center, at least one transmission opportunity was evident for 85% of patients. This implies that patient-to-patient transmission is the major mode of A. baumannii acquisitions in health facilities. Moreover, all patients who died immediately (

Identifying patients at risk for bloodstream infection (BSI) due to Acinetobacter baumannii - Acinetobacter calcoaceticus complex (ABC) and providing early appropriate therapy are critical for improving patient outcomes. A retrospective matched case-control study was conducted to investigate the risk factors for BSI due to ABC in patients admitted to the Detroit Medical Center (DMC) between January 2006 and April 2009. The cases were patients with BSI due to ABC; the controls were patients not infected with ABC. Potential risk factors were collected 30 days prior to the ABC-positive culture date for the cases and 30 days prior to admission for the controls. A total of 245 case patients were matched with 245 control patients. Independent risk factors associated with BSI due to ABC included a Charlson's comorbidity score of ≥3 (odds ratio [OR], 2.34; P = 0.001), a direct admission from another health care facility (OR, 4.63; P < 0.0001), a prior hospitalization (OR, 3.11; P < 0.0001), the presence of an indwelling central venous line (OR, 2.75; P = 0.011), the receipt of total parenteral nutrition (OR, 21.2; P < 0.0001), the prior receipt of β-lactams (OR, 3.58; P < 0.0001), the prior receipt of carbapenems (OR, 3.18; P = 0.006), and the prior receipt of chemotherapy (OR, 15.42; P < 0.0001). The median time from the ABC-positive culture date to the initiation of the appropriate antimicrobial therapy was 2 days (interquartile range [IQR], 1 to 3 days). The in-hospital mortality rate was significantly higher among case patients than among control patients (OR, 3.40; P < 0.0001). BSIs due to ABC are more common among critically ill and debilitated institutionalized patients, who are heavily exposed to health care settings and invasive devices.

Objective.To determine whether increases in contact isolation precautions are associated with decreased adherence to isolation practices among healthcare workers (HCWs).Design.Prospective cohort study from February 2009 to October 2009.Setting.Eleven teaching hospitals.Participants.HCWs.Methods.One thousand thirteen observations conducted on HCWs. Additional data included the number of persons in isolation, types of HCWs, and hospital-specific contact precaution practices. Main outcome measures included compliance with individual components of contact isolation precautions (hand hygiene before and after patient encounter, donning of gown and glove upon entering a patient room, and doffing upon exiting) and overall compliance (all 5 measures together) during varying burdens of isolation.Results.Compliance with hand hygiene was as follows: prior to donning gowns/gloves, 37.2%; gowning, 74.3%; gloving, 80.1%; doffing of gowns/gloves, 80.1%; after gown/glove removal, 61%. Compliance with all components was 28.9%. As the burden of isolation increased (20% or less to greater than 60%), a decrease in compliance with hand hygiene (43.6%—4.9%) and with all 5 components (31.5%—6.5%) was observed. In multivariable analysis, there was an increase in noncompliance with all 5 components of the contact isolation precautions bundle (odds ratio [OR], 6.6 [95% confidence interval (CI), 1.15-37.44];P= .03) and in noncompliance with hand hygiene prior to donning gowns and gloves (OR, 10.1 [95% CI, 1.84—55.54];P= .008) associated with increasing burden of isolation.Conclusions.As the proportion of patients in contact isolation increases, compliance with contact isolation precautions decreases. Placing 40% of patients under contact precautions represents a tipping point for noncompliance with contact isolation precautions measures.

Background Multi-drug-resistant organisms (MDRO) pose a growing burden, including in non-hospital settings. Delay in initiation of appropriate antimicrobial therapy (DAAT) upon admission to an acute care hospital is common and is associated with worse outcomes. The aim of this study was to develop a prediction score for MDRO infection upon admission, in order to improve patients’ outcomes and avoid misuse of broad-spectrum antimicrobials. Methods A retrospective case–control analysis was conducted at Assaf Harofeh Medical Center, Israel, comparing adult patients with MDRO infections diagnosed in the first 48 hours of hospitalization to patients presenting with non-MDRO sepsis (i.e., patients with microbiologically confirmed non-MDRO infection, or patients with non-microbiologically confirmed sepsis). MDROs were determined by clinical laboratory testing. Patients were identified over four consecutive months (August–December 2016). A multivariable logistic regression of predictors for MDRO infection upon admission was used to develop the prediction score. Results Ninety-five of 818 total patients (11.6%) had MDRO infection. The final score included 10 parameters: (1) home therapy (IV therapy, wound care, or specialized nursing care, 16 points), (2) routine (at least weekly) outpatient clinic visits in the past 3 months (15 points), (3) history (2 years) of past MDRO colonization (14 points), (4) any antibiotics in the preceding 3 months (12 points), (5) invasive procedure in the past 6 months (11 points), (6) elderly (≥65 years old, 10 points), (7) hemiplegia or paraplegia (8 points), (8) resident of long-term care facility (7 points), (9) severe sepsis (i.e., severe sepsis, septic shock, or multi-organ failure, 6 points), and (10) acute kidney injury (5 points). A cutoff of ≥24 points had a sensitivity of 90%, a specificity of 73% and an ROC AUC = 0.88 (figure). Conclusion This study presents the development of a new prediction score for MDRO infection upon admission, based on parameters that could easily be extracted at bedside for patients admitted with sepsis. A future prospective interventional study is needed in order to validate the score, captured at bedside electronically, in terms of improving patients’ outcomes. Disclosures All authors: No reported disclosures.

Background. Background The World Health Organization has declared carbapenem-resistant Enterobacteriaceae (CRE) as a worldwide public health threat. Analyzing the epidemiology of CRE was derived from cohorts consisting primarily of Klebsiella pneumoniae isolates. The second most frequent CRE is Enterobacter (CREn), but its molecular and clinical epidemiology differ from that of K. pneumoniae, and it has not been analyzed while implementing updated methodological tools and design. Methods A matched case-case–control investigation was conducted at Shamir (Assaf Harofeh) Medical Center, Israel, for calendar years 2007–2017. Each CREn case was matched to a carbapenem-susceptible Enterobacter (CSEn) case and to an uninfected control (1:1:1 ratio). Logistic and Cox regression-matched analyses were conducted in order to study predictors and outcomes of CREn colonization and/or infection, respectively. Results The study included 216 cases (72 in each group). Numerous predictors were significantly associated with CREn as per bivariable analyses, but the only independent significant predictors were: (1) recent (3 months) exposure to fluoroquinolones (aOR=2.94, P = 0.04), (2) intensive care unit stay in current hospitalization prior to culture (aOR=3.56, P = 0.003), and (3) a rapidly fatal McCabe score (aOR=0.471, P = 0.01). Patients with CREn suffered from significant delays in instituting appropriate antimicrobials (P = 0.03), and for those who survived the hospitalization, were more frequently discharged to a long-term care facility after being admitted to the index hospitalization from home (aOR=3.3, P = 0.02). Conclusion This case-case–control-matched investigation of CREn epidemiology, revealed a unique modifiable predictor, i.e., recent fluoroquinolone exposure, which could represent a target for stewardship intervention. The case-case–control-matched design allowed for the control of numerous confounders previously reported to be associated with CREn but may represent a risk factor for Enterobacter infection in general. As with other CRE, CREn carriers suffer from significant delays in initiation of appropriate antimicrobials and from worse outcomes. Disclosures All authors: No reported disclosures.

Background In the era of widespread resistance, there are two events in the course of a hospitalized septic patient where the majority of empiric prescription errors occur: (1) infections upon admission (UA) due to multi-drug-resistant organisms (MDRO) and (2) nosocomial infections due to extensively drug-resistant organisms (XDRO). These errors seriously impact patient outcomes and the ecological burden of resistance. Our objective was to develop a tool, to calculate the probability of MDRO UA, and nosocomial XDRO infections, in order to reduce delays in initiating appropriate therapy to the “right population,” i.e., with “resistant pathogens,” while avoiding overuse of broader (frequently more toxicת less efficacious) therapeutics to the “wrong population,” i.e., with “susceptible pathogens.” Methods Retrospective case–control analyses were conducted for septic adults at Shamir Medical Center, Israel (2016). Logistic regression was used to develop models of risk factors. All parameters incorporated into the models were readily accessible at the point of care. The performances of the development cohorts, and on 8 other validation cohorts, were assessed by the area under the receiver operating characteristic curve (ROC AUC). A web calculator (mobile modifiable) was generated. Results A total of 4,199 patients were enrolled: 2,472 with sepsis UA, and 1,727 with nosocomial sepsis. The “MDR UA score” included 10 parameters and with a cutoff of ≥22 points, had a ROC AUC of 0.85 (sensitivity 86%, NPV 98%). The “Nosocomial XDR score” included 7 parameters and with a cutoff of ≥36 points, had a ROC AUC of 0.88 (sensitivity 90%, NPV 96%). The median ROC AUC was 0.75 among the validation cohorts of the “MDR UA score,” and 0.66 among the “Nosocomial XDR score.” A free web tool was generated: https://assafharofe.azurewebsites.net/. Conclusion A simple electronic calculator was generated to aid in bedside empiric prescription practices. The tool is composed of two scores to assist in common scenarios where the majority of errors occur. Prospective interventional investigations, should trial the performances of this tool in improving patient outcomes and the ecological burden in the facility. Disclosures All authors: No reported disclosures.

Objectives To quantify the effect of nosocomial bloodstream infection (BSI) on older adults, including mortality, length of stay (LOS), and costs attributed to BSI. Design Retrospective cohort study. Setting Eight acute care hospitals (7 community hospitals and 1 tertiary university-affiliated facility) belonging to the Duke Infection Control Outreach Network (DICON) from the states of North Carolina and Virginia. Participants Elderly patients over 65 years of age. Measurements A multistate, multicenter, matched, retrospective cohort study was conducted from January 1994 through June 2002 in eight hospitals from the Southern-Central United States. Patients aged >65 years with nosocomial BSI were enrolled. Controls without bloodstream infection were matched to cases. Outcomes during the 90-day period following hospital discharge were evaluated to determine the association between BSI and mortality, hospital costs, and LOS. Results Eight-hundred thirty cases and 830 matched controls were identified, all with a mean age of 74.4 years. Among cases, 81% of BSIs were central line-associated and Staphylococcus aureus was the most common pathogen accounting for 34.6% of infections (2/3 were methicillin resistant). The mortality rate of cases was 49.4%, compared to 33.2% for controls (OR = 2.1, P

Acinetobacter baumannii has become a leading cause of bloodstream infections (BSI) in health care settings. Although the incidence of infection with carbapenem- and ampicillin-sulbactam-resistant (CASR) A. baumannii has increased, there is a scarcity of studies which investigate BSI caused by CASR A. baumannii . A retrospective cohort study was conducted on adult patients with BSI caused by A. baumannii and who were admitted to the Detroit Medical Center between January 2006 and April 2009. Medical records were queried for patients' demographics, antimicrobial exposures, comorbidities, hospital stay, and clinical outcomes. Bivariate analyses and logistic regression were employed in the study. Two hundred seventy-four patients with BSI caused by A. baumannii were included in the study: 68 (25%) caused by CASR A. baumannii and 206 (75%) caused by non-CASR A. baumannii . In multivariate analysis, factors associated with BSI caused by CASR A. baumannii included admission with a rapidly fatal condition (odds ratio [OR] = 2.83, 95% confidence interval [CI] = 1.27 to 6.32, P value = 0.01) and prior use of antimicrobials (OR = 2.83, 95% CI = 1.18 to 6.78, P value = 0.02). In-hospital mortality rates for BSI caused by CASR A. baumannii were significantly higher than those for non-CASR A. baumannii -induced BSI (43% versus 20%; OR = 3.0, 95% CI = 1.60 to 5.23, P value < 0.001). However, after adjusting for potential confounders, the association between BSI caused by CASR A. baumannii and increased risk of in-hospital mortality was not significant (OR = 1.15, 95% CI = 0.51 to 2.63, P value = 0.74). This study demonstrated that CASR A. baumannii had a distinct epidemiology compared to more susceptible A. baumannii strains; however, clinical outcomes were similar for the two groups. Admission with a rapidly fatal condition was an independent predictor for both CASR A. baumannii and in-hospital mortality.

A case-case-control study was conducted to identify independent risk factors for recovery of Escherichia coli strains producing CTX-M-type extended-spectrum β-lactamases (CTX-M E. coli ) within a large Southeastern Michigan medical center. Unique cases with isolation of ESBL-producing E. coli from February 2010 through July 2011 were analyzed by PCR for bla CTX-M , bla TEM , and bla SHV genes. Patients with CTX-M E. coli were compared to patients with E. coli strains not producing CTX-M-type ESBLs (non-CTX-M E. coli ) and uninfected controls. Of 575 patients with ESBL-producing E. coli , 491 (85.4%) isolates contained a CTX-M ESBL gene. A total of 319 (84.6%) patients with CTX-M E. coli (282 [74.8%] CTX-M-15 type) were compared to 58 (15.4%) non-CTX-M E. coli patients and to uninfected controls. Independent risk factors for CTX-M E. coli isolation compared to non-CTX-M E. coli included male gender, impaired consciousness, H2 blocker use, immunosuppression, and exposure to penicillins and/or trimethoprim-sulfamethoxazole. Compared to uninfected controls, independent risk factors for isolation of CTX-M E. coli included presence of a urinary catheter, previous urinary tract infection, exposure to oxyimino-cephalosporins, dependent functional status, non-home residence, and multiple comorbid conditions. Within 48 h of admission, community-acquired CTX-M E. coli ( n = 51 [16%]) and non-CTX-M E coli ( n = 11 [19%]) strains were isolated from patients with no recent health care contacts. CTX-M E. coli strains were more resistant to multiple antibiotics than non-CTX-M E. coli strains. CTX-M-encoding genes, especially bla CTX-M-15 type, represented the most common ESBL determinants from ESBL-producing E. coli , the majority of which were present upon admission. Septic patients with risk factors for isolation of CTX-M E. coli should be empirically treated with appropriate agents. Regional infection control efforts and judicious antibiotic use are needed to control the spread of these organisms.

Antimicrobial resistance is a continuing, growing, worldwide iatrogenic complication of modern medical care. Carbapenem resistance among certain pathogens poses a significant challenge. In order to reduce the spread of these nearly untreatable pathogens, preventative efforts should be directed at reducing patient-to-patient transmission and preventing the emergence of resistance among susceptible strains. One theoretical intervention to reduce the emergence of resistance is establishing and strictly adhering to an antimicrobial stewardship program. However, data pertaining to the direct effect of stewardship in curtailing carbapenem resistance among epidemiologically significant organisms are scarce. In this report, we review the potential biases associated with data interpretation in this research field, and we review the data pertaining to the impact of stewardship in curbing carbapenem resistance in three significant groups of pathogens: Pseudomonas aeruginosa, Enterobacteriaceae and Acinetobacter baumannii.

The prevalence of multidrug resistant Gram-negative organisms is increasing worldwide. The Infectious Diseases Society of America has previously singled out groups of pathogens with the highest threat, the majority of which are Gram-negative bacilli. These isolates are prevalent not only in intensive-care units of acute-care facilities, but are also found among residents of long-term care facilities with various levels of care, and occasionally among patients without exposure to healthcare systems. Advanced age is an independent predictor for carriage of many of these organisms, and elderly patients are subjected to worse outcomes following the acquisition of resistant Gram-negatives. Due to their frequent admissions and transfers across different healthcare facilities within a region, the elderly constitute important epidemiological reservoirs for these bacteria. Containing the acquisitions of resistant Gram-negatives among the elderly could be achieved through reduction of either 1) selective pressure (e.g. less antibiotics) or 2) colonization pressure (e.g. less exposure to resistant bacteria). This manuscript will review the present situation of multidrug resistant Gram-negative organisms, especially among the elderly, and the infection control interventions that might mitigate their further spread.

Although much is known about vancomycin-resistant (VR) Enterococcus faecium , little is known about the epidemiology of VR Enterococcus faecalis . The predilection of VR E. faecalis to transfer the vancomycin resistance determinant to Staphylococcus aureus is much greater than that of VR E. faecium . The epidemiology of VR E. faecalis has important implications regarding the emergence of vancomycin-resistant S. aureus (VRSA); 8 of 13 reported VRSA cases have been from Michigan. A retrospective case-case-control study was conducted at the Detroit Medical Center, located in southeastern Michigan. Unique patients with VR E. faecalis infection were matched to patients with strains of vancomycin-susceptible (VS) E. faecalis and to uninfected controls at a 1:1:1 ratio. Five hundred thirty-two VR E. faecalis cases were identified and were matched to 532 VS E. faecalis cases and 532 uninfected controls. The overall mean age of the study cohort ( n = 1,596) was 63.0 ± 17.4 years, and 747 (46.8%) individuals were male. Independent predictors for the isolation of VR E. faecalis (but not VS E. faecalis ) compared to uninfected controls were an age of ≥65 years, nonhome residence, diabetes mellitus, peripheral vascular disease, exposure to cephalosporins and fluoroquinolones in the prior 3 months, and immunosuppressive status. Invasive procedures and/or surgery, chronic skin ulcers, and indwelling devices were risk factors for both VR E. faecalis and VS E. faecalis isolation. Cephalosporin and fluoroquinolone exposures were unique, independent predictors for isolation of VR E. faecalis . A majority of case patients had VR E. faecalis present at the time of admission. Control of VR E. faecalis , and ultimately VRSA, will likely require regional efforts focusing on infection prevention and antimicrobial stewardship.

Background.Carbapenem-resistant Enterobacteriaceae (CRE) are rapidly emerging worldwide. Control group selection is critically important when analyzing predictors of antimicrobial resistance. Focusing on modifiable risk factors can optimize prevention and resource expenditures. To identify specific predictors of CRE, patients with CRE were compared with 3 control groups: (1) patients with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, (2) patients with non-ESBL-containing Enterobacteriaceae, and (3) uninfected controls.Design.Matched multivariable analyses.Patients and Setting.Patients possessing CRE that were isolated at Detroit Medical Center from September 1, 2008, to August 31, 2009.Methods.Patients were matched (1:1 ratio) to the 3 sets of controls. Matching parameters included (1) bacteria type, (2) hospital/ facility, (3) unit/clinic, (4) calendar year, and (5) time at risk (ie, from admission to culture). Matched multivariable analyses were conducted between uninfected controls and patients with CRE, ESBL, and non-ESBL Enterobacteriaceae. Models were also designed comparing patients with CRE to patients with ESBL, patients with non-ESBL Enterobacteriaceae, and all 3 non-CRE groups combined.Results.Ninety-one unique patients with CRE were identified, and 6 matched models were constructed. Recent (less than 3 months) exposure to antibiotics was the only parameter that was consistently associated with CRE, regardless of the group to which CRE was compared, and was not independently associated with isolation of ESBL or non-ESBL Enterobacteriaceae.Conclusions.Exposure to antibiotics within 3 months was an independent predictor that characterized patients with CRE isolation. As a result, antimicrobial stewardship efforts need to become a major focus of preventive Interventions. Regulatory focus regarding appropriate antimicrobial use might decrease the detrimental effects of antibiotic misuse and spread of CRE.

In published studies, cohorts of patients with bacteremia due to vancomycin-resistant Enterococcus (VRE) have predominantly been infected with Enterococcus faecium . Little is known about the epidemiology and outcomes associated with bacteremia due to VR Enterococcus faecalis . A retrospective study of isolates obtained from January 2008 to October 2010 was conducted at Detroit Medical Center (DMC). Unique patients with blood cultures positive for VRE were reviewed. Outcomes were analyzed using logistic regression. During the study period, 105 cases of bacteremia due to VR E. faecalis and 197 cases of bacteremia due to VR E. faecium were identified. The mean age in the study cohort was 61.5 ± 15 years; 162 subjects (53.6%) were male. After controlling for a propensity score, bacteremia due to VR E. faecalis was associated with >2-fold-lower in-hospital mortality than bacteremia due to VR E. faecium . Interestingly, bacteremia due to VR E. faecalis was associated with longer hospital stay after VRE isolation, although total length of stay was similar for groups with VR E. faecalis and VR E. faecium . Bacteremia due to VR E. faecalis was associated with a >2-fold-lower risk for mortality than bacteremia due to VR E. faecium , possibly due to the availability of β-lactam therapeutics for treatment of VR E. faecalis .

Ertapenem is active against extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae organisms but inactive against Pseudomonas aeruginosa and Acinetobacter baumannii . Due to a lack of therapeutic data for ertapenem in the treatment of ESBL bloodstream infections (BSIs), group 2 carbapenems (e.g., imipenem or meropenem) are often preferred for treatment of ESBL-producing Enterobacteriaceae , although their antipseudomonal activity is unnecessary. From 2005 to 2010, 261 patients with ESBL BSIs were analyzed. Outcomes were equivalent between patients treated with ertapenem and those treated with group 2 carbapenems (mortality rates of 6% and 18%, respectively; P = 0.18).

Summary Background Group B Streptococcus (GBS) is a known causative pathogen of neonatal sepsis, but the epidemiology in non-pregnant adults is less studied. Methods Retrospective case–control and cohort analyses of risk factors and outcomes of GBS infections among non-pregnant adults were conducted at the Detroit Medical Center from January 2005 to May 2010. Uninfected controls were matched to cases in a 3:1 ratio. Data were obtained from charts and pharmacy records. Identification of the bacteria and antimicrobial susceptibility testing were determined by MicroScan. Cox regression was used for matched multivariate analyses. Results Thirty-two patients with GBS infections were identified and were matched and compared to 96 controls. Compared to controls, patients with GBS infection were significantly younger. Immunosuppression, attributable mainly to neutropenia and recent use of glucocorticoids, was an independent predictor for GBS infection (odds ratio 2.7, p =0.03). Nine (28%) of the patients with GBS infection had bacteriological failure despite the administration of appropriate antimicrobial therapy. Of the 10 patients with bloodstream infections (BSI), three had endocarditis and four had central nervous system (CNS) infections. During the study period the incidence of infections decreased, but the rates of resistance to erythromycin and clindamycin increased. Conclusions GBS, previously considered a genitourinary pathogen, has emerged as a non-nosocomial opportunistic pathogen causing BSI, endocarditis, and CNS infections. Immunosuppression, particularly transient immunosuppressed states, was an independent predictor for GBS BSI. Resistance rates to macrolides and clindamycin continue to increase, and should be closely monitored.

Background. Colistin, originally abandoned due to high rates of nephrotoxicity, has been recently reintroduced due to activity against carbapenem-resistant Gram-negative organisms. Recent literature, largely obtained from outside the United States, suggests a lower rate of nephrotoxicity than historically reported. Methods. A retrospective cohort of all patients who received colistin for $48 hours at the Detroit Medical Center over a 5-year period was performed to determine the rate of colistin-associated nephrotoxicity as defined by the RIFLE criteria. Results. Fifty-four (43%) patients in the cohort developed nephrotoxicity. Patients who experienced nephrotoxicity after colistin administration were in the Risk (13%), Injury (17%), or Failure (13%) categories per RIFLE criteria. Patients who developed nephrotoxicity received significantly higher mean doses than those who did not (5.48 mg/kg per day vs 3.95 mg/kg per day; P , .001), and the toxicity occurred in a dose-dependent fashion. Independent predictors for nephrotoxicity were a colistin dose of $5.0 mg/kg per day of ideal body weight (odds ratio [OR], 23.41; 95% confidence interval [CI], 5.3‐103.55), receipt of concomitant rifampin (OR, 3.81; 95% CI, 1.42‐10.2), and coadministration of $3 concomitant nephrotoxins (OR, 6.80; 95% CI, 1.42‐32.49). Conclusions. In this retrospective cohort, nephrotoxicity (as defined by RIFLE criteria) occurred among 43% of treated patients in a dose-dependent manner. Higher colistin doses, similar to those commonly used in the United States, led to a relatively high rate of nephrotoxicity. These data raise important questions regarding the safe use of colistin in the treatment of multidrug-resistant pathogens.

Background The healthcare environment has been established as a reservoir for human pathogens and specifically multidrug-resistant organisms (MDRO). High touch surfaces and fomites in a patient’s room mediate transmission between infected and uninfected patients and personnel. Efforts to reduce hospital-associated infections due to MDROs often focus on room cleaning; however, adherence to and thoroughness of cleaning pose significant challenges. Methods A crossover trial was implemented in January 2016 (for 15 months) at Assaf Harofeh Medical Center (Israel) in four identical medical units. Single-use wipes (Clinell®; universal wipes and sporicidal wipes for rooms of patients with C. difficile), were compared with common practices which consisted of reusable cloths and bleach (1,000–5,000 ppm). Six-month cleaning and intervention periods were used on units in alternating sequences, separated by washout periods. Cleaning was monitored twice a week (bedrail, bedside table, clinical binder, call button, and lamp switch), by a fluorescent marker system (Clinell®). Comparisons used GEE with clustering for room. Staff were surveyed on intervention feasibility, acceptability, and satisfaction. Results Complete cleaning in all five test locations was found in 23% of 400 total assessments and was more common in the intervention group (34% vs. 12%; OR = 3.7; P < 0.001). Cleaning adherence was highest for the bed rail (71%) and lowest for the call button (38%). The use of wipes had the largest effect on adherence for the light switch (59% vs. 26%; OR = 4.2; P < 0.001). Intervention timing was not associated with overall adherence (P = 0.10). 94% of staff reported overall satisfaction of “very good” or “excellent,” and 90% of staff reported that use of the wipes shortened the cleaning process. Conclusion The use of cleaning wipes resulted in greater adherence to room cleaning and the method was reported to be acceptable to staff. Future aims of this large study (over 10,000 patients were enrolled and data collection not yet completed) are to determine the impact of this intervention on rates of hospital-acquired infections, MDRO acquisitions, and mortality. Disclosures E. T. Martin, Clinell: Grant Investigator, Research grant. D. Marchaim, Clinell: Grant Investigator, Grant recipient.

Background Intra-abdominal infections (IAI) constitute a common reason for hospitalization. However, there is lack of standardization in empiric management of (1) anaerobes, (2) enterococci, (3) fungi, and (4) multidrug-resistant organisms (MDRO). The recommendation is to institute empiric coverage for some of these organisms in “high-risk community-acquired” or in “healthcare-associated” infections (HCAI), but exact definitions are not provided. Methods Epidemiological study of IAI was conducted at Assaf Harofeh Medical Center (May–November 2013). Logistic and Cox regressions were used to analyze predictors and outcomes of IAI, respectively. The performances of established HCAI definitions to predict MDRO-IAI upon admission were calculated by receiver operating characteristic (ROC) curve analyses. Results After reviewing 8219 discharge notes, 253 consecutive patients were enrolled (43 [17%] children). There were 116 patients with appendicitis, 93 biliary infections, and 17 with diverticulitis. Cultures were obtained from 88 patients (35%), and 44 of them (50%) yielded a microbiologically confirmed IAI: 9% fungal, 11% enterococcal, 25% anaerobic, and 34% MDRO. Eighty percent of MDRO-IAIs were present upon admission, but the area under the ROC curve of predicting MDRO-IAI upon admission by the commonly used HCAI definitions were low (0.73 and 0.69). Independent predictors for MDRO-IAI were advanced age and active malignancy. Conclusions Multidrug-resistant organism-IAIs are common, and empiric broad-spectrum coverage is important among elderly patients with active malignancy, even if the infection onset was outside the hospital setting, regardless of current HCAI definitions. Outcomes analyses suggest that empiric regimens should routinely contain antianaerobes (except for biliary IAI); however, empiric antienterococcal or antifungals regimens are seldom needed.