Despite the rise and impact of methicillin-resistant Staphylococcus aureus, methicillin-susceptible S. aureus (MSSA) continues to contribute to the overall burden of S. aureus infections, representing Ն50% of clinical S. aureus strains (1-3) with known appreciable mortality outcomes (4, 5). Prevailing evidence supports the use of semisynthetic penicillins, such as oxacillin or nafcillin, or the first-generation cephalosporin cefazolin in preference to vancomycin as optimal therapy for MSSA bloodstream infections (BSI) (6-11). Moreover, an early switch from vancomycin to either nafcillin or cefazolin with definitive MSSA identification was associated with a 69% risk reduction in 30-day in-hospital mortality in a recent retrospective cohort study (11).Cefazolin offers a convenient dosing scheme with a favorable adverse event profile, allowing many institutions to consider its use in the management of MSSA infections (12). However, deepseated infections with a high burden of S. aureus have been shown to overproduce certain types of ␤-lactamases, rendering cefazolin inactive and thus resulting in possible treatment failure (13-15). Furthermore, current practice guidelines, such as those for infective endocarditis, suggest reserving the use of cefazolin for patients with nonanaphylactoid-type penicillin allergies (7). As a result, clinician preference for either nafcillin or oxacillin for more severe or deep-seated MSSA infection has evolved in practice, while the use of cefazolin in this setting remains controversial (12,16,17). The purpose of this study was to evaluate and compare treatment outcomes using cefazolin or oxacillin for MSSA BSI, including deep-seated sources of infection.(Portions of this paper were presented as a poster at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy, 5 to 9 September 2014, Washington, DC.) MATERIALS AND METHODS Study design.From January 2010 to April 2013, a retrospective cohort study was conducted at Rush University Medical Center (RUMC) and Northwestern Memorial Hospital (NMH), two tertiary care academic medical centers in Chicago, IL. The study methods were reviewed and approved by the institutional review boards at RUMC, NMH, and Midwestern University. Adult patients who received in-hospital definitive treatment with cefazolin or oxacillin within 48 h of finalized blood cultures with MSSA were eligible for inclusion in the study. Patients were included only once, and only the first (index) in-hospital admission during the study period was evaluated. The index blood culture was the first blood culture growing MSSA during the index admission. Patients were excluded if they (i) were Ͻ18 years of age, (ii) received antibiotics other than cefazolin or oxacillin for definitive treatment of an MSSA BSI, (iii) received Ն5 days of an empirical antibiotic agent active against MSSA prior to definitive treatment with cefazolin or oxacillin, (iv) had a docu-

Antibiotics contained in ABLC are systemically absorbed, though at low levels, and have been associated with systemic toxicities. Antibiotics to which a patient has had a potentially life-threatening reaction should not be used in ABLC. Particular attention should be paid to an individual's antibiotic allergy history prior to implantation of any ABLC.

Adverse effects of linezolid are typically limited to diarrhea, nausea, and headache when shorter durations are used; however, as extended durations of linezolid therapy are increasingly more common, additional monitoring parameters should be considered in these patients. We describe a unique case of hypoglycemia, lactic acidosis, and pancreatitis related to an extended duration of linezolid therapy. A 52-year-old woman presented with altered mental status, abdominal pain, and hypotension following six weeks of linezolid and ertapenem therapy. Laboratory data revealed an initial blood glucose of 40 mg/dL and metabolic acidosis secondary to lactic acidosis. Finally, her abdominal pain on admission was likely related to an enlarged pancreas noted on computed tomography of her abdomen. Due to suspected linezolid toxicity, the patient received two intermittent hemodialysis sessions to remove linezolid and correct the metabolic acidosis. Given limited data on long-term monitoring of patients receiving extended durations of linezolid therapy, we suggest periodic monitoring of lactate, arterial blood gas, and blood glucose. If patients present with this triad of symptoms secondary to linezolid therapy, adverse effects should be treated with dextrose and intravenous thiamine while reserving hemodialysis for those with metabolic acidosis refractory to thiamine.

Purpose To elucidate the considerations pharmacists have when using concomitant vancomycin and piperacillin/tazobactam (VPT) and strategies implemented across hospitals in response to published data on this phenomenon. Methods A survey of pharmacist members of the infectious diseases and critical care (CC) practice and research networks of the American College of Clinical Pharmacy was conducted. Participants were grouped based on their belief (yes or no) in the association between VPT and acute kidney injury (AKI) and queried regarding AKI with VPT, antimicrobial stewardship practices, and demographics. Descriptive statistics were performed. Between‐group responses were compared using χ2 or Fisher's exact tests. Results There were 238 responses. Most (88.7%) respondents believed combination VPT is associated with greater expected odds of AKI development than vancomycin monotherapy or with cefepime. Nonbelievers more commonly practiced in CC or emergency medicine (P = .006) and less frequently recommended the combination in patients already experiencing AKI (64% vs 7.4%, P < .001) and in patients with chronic kidney disease class III or IV (56.9% vs 3.7%, P < .001). Opinions varied regarding risk factors for and odds of AKI development in specific scenarios. Respondents who believed combination VPT is associated with greater odds of AKI development more frequently provided formal (18% vs 0, P = .01) and informal (73% vs 33.3%, P < .001) education on potential AKI from combination VPT and discouraged empiric combination VPT in favor of other combination(s) (40.8% vs 14.8%, P = .01). Other AMS strategies were used to a similar extent regardless of belief in the association of VPT with AKI. Conclusion Most respondents, particularly those practicing in CC and emergency medicine, believe combination VPT is associated with AKI development. These beliefs have affected antimicrobial recommendations and educational efforts. The impact of these beliefs on patient outcomes and health care expenditures requires further investigation.

Objective: To develop a regional antibiogram within the Chicagoland metropolitan area and to compare regional susceptibilities against individual hospitals within the area and national surveillance data. Design: Multicenter retrospective analysis of antimicrobial susceptibility data from 2017 and comparison to local institutions and national surveillance data. Setting and participants: The analysis included 51 hospitals from the Chicago–Naperville–Elgin Metropolitan Statistical Area within the state of Illinois. Overall, 18 individual collaborator hospitals provided antibiograms for analysis, and data from 33 hospitals were provided in aggregate by the Becton Dickinson Insights Research Database. Methods: All available antibiogram data from calendar year 2017 were combined to generate the regional antibiogram. The final Chicagoland antibiogram was then compared internally to collaborators and externally to national surveillance data to assess its applicability and utility. Results: In total, 167,394 gram-positive, gram-negative, fungal, and mycobacterial isolates were collated to create a composite regional antibiogram. The regional data represented the local institutions well, with 96% of the collaborating institutions falling within ±2 standard deviations of the regional mean. The regional antibiogram was able to include 4–5-fold more gram-positive and -negative species with ≥30 isolates than the median reported by local institutions. Against national surveillance data, 18.6% of assessed pathogen–antibiotic combinations crossed prespecified clinical thresholds for disparity in susceptibility rates, with notable trends for resistant gram-positive and gram-negative bacteria. Conclusions: Developing an accurate, reliable regional antibiogram is feasible, even in one of the largest metropolitan areas in the United States. The biogram is useful in assessing susceptibilities to less commonly encountered organisms and providing clinicians a more accurate representation of local antimicrobial resistance rates compared to national surveillance databases.