Antimicrobial use for asymptomatic bacteriuria-First, do no harm.

OBJECTIVE: Administration of antimicrobials to patients with asymptomatic bacteriuria (ASB) is a common error that can lead to worse outcomes. However, controlled analyses quantifying the commonality and impact of this practice are lacking. We analyzed the independent predictors for antimicrobials misuse in ASB and quantified the impact of this practice on clinical outcomes. DESIGN: Retrospective case-control and cohort analyses for calendar year 2017. SETTING: Tertiary-care, university-affiliated medical center. PATIENTS: The study included adult (>18 years) patients with positive urine culture. Pregnant women, renal transplant recipients, and patients who underwent urologic procedures were excluded. METHODS: ASB was determined according to US Centers for Disease Control and Prevention (CDC) criteria. Multivariable logistic regression models were constructed to analyze predictors and outcomes associated with antimicrobial use for patients with ASB. RESULTS: The study included 1,530 patient-unique positive urine cultures. Among these patients, 610 patients (40%) were determined to have ASB. Of the 696 isolates, 219 (36%) were multidrug-resistant organisms (MDROs). Also, 178 (29%) patients received antimicrobials specifically due to the ASB. Independent predictors for improper administration of antimicrobials were dependent functional status (adjusted odds ratio [aOR], 2.3; 95% CI, 1.4-3.6) and male sex (aOR, 2; 95% CI, 1.25-2.6). Use of antimicrobials was independently associated with re-hospitalizations (aOR, 1.7; 95% CI, 1.1-2.6) and later, acute Clostridioides difficile infections (CDI) in the following 90 days (aOR, 4.5; 95% CI, 2-10.6). CONCLUSIONS: ASB is a common condition, frequently resulting from an MDRO. Male sex and poor functional status were independent predictors for mistreatment, and this practice was independently associated with rehospitalizations and CDI in the following 90 days.

The impact of improper empirical usage of antipseudomonals on admission to an acute care hospital.

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 epidemiological impact and significance of carbapenem resistance in Pseudomonas aeruginosa bloodstream infections: a matched case-case-control analysis.

A case-case-control investigation (N = 255 patients) explored the epidemiology of carbapenem-resistant Pseudomonas aeruginosa (CRPA). Recent exposure to carbapenems and a rapidly fatal condition should prompt practitioners to shorten delays in initiating appropriate therapy, which can adversely impact CRPA outcomes, as opposed to the isolated impact of the carbapenem resistance determinant.

[THE EPIDEMIOLOGY OF CLOSTRIDIUM DIFFICILE INFECTIONS AND ASPECTS PERTAINING TO TREATMENT WITH VANCOMYCIN AT ASSAF HAROFEH MEDICAL CENTER].

BACKGROUND: The epidemiology of Clostridium difficile infections (CDI) have evolved dramatically in the past decade. Vancomycin is the treatment of choice for moderate to severe CDI. However, controlled comparative data pertaining to mild CDI is lacking. Furthermore, the potential impact of vancomycin treatment on subsequent vancomycin-resistant Enterococcus (VRE) isolation remains unknown. METHODS: A retrospective cohort analysis was executed at the Assaf Harofeh Medical Center, from 2013 to 2015. Adult patients (>18 years) with a first episode of acute CDI, determined per pre-established criteria, were enrolled. The efficacy of vancomycin vs. metronidazole among patients with mild CDI, and the independent association of oral vancomycin treatment during the acute CDI and later (up to 18 months) VRE isolation, was analyzed by logistic regression. RESULTS: A total of 260 patients with CDI were enrolled. The majority were elderly (75%), and 56% had moderate to severe disease. Among 75 patients with mild disease, no differences were observed in terms of clinical outcomes between vancomycin or metronidazole treatment. Metronidazole remained non-inferior even after incorporating a prediction score to control for confounders associated with being a "vancomycin case". In multivariable analysis, oral vancomycin treatment during the acute CDI was the strongest independent predictor for later isolation of VRE (aOR=74, p=0.004). CONCLUSIONS: Our study suggests that metronidazole should remain the recommended treatment of choice for mild CDI, due to clinical non-inferiority and an apparent association between vancomycin therapy and subsequent VRE isolation on an individual patient level analysis.

Therapeutic Management of Pseudomonas aeruginosa Bloodstream Infection Non-Susceptible to Carbapenems but Susceptible to "Old" Cephalosporins and/or to Penicillins.

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-ß-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.

Clinical and molecular epidemiology of Acinetobacter baumannii bloodstream infections in an endemic setting.

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 (<24 h of admission) were infected with a single clone (ST457; relative risk = 1.6; p = 0.05). CONCLUSION: This preliminary analysis should prompt further investigation by mapping genomic virulence determinants among A. baumannii ST457 lineage compared with other strains.