Trial of Vancomycin and Cefazolin as Surgical Prophylaxis in Arthroplasty.

BACKGROUND: The addition of vancomycin to beta-lactam prophylaxis in arthroplasty may reduce surgical-site infections; however, the efficacy and safety are unclear. METHODS: In this multicenter, double-blind, superiority, placebo-controlled trial, we randomly assigned adult patients without known methicillin-resistant Staphylococcus aureus (MRSA) colonization who were undergoing arthroplasty to receive 1.5 g of vancomycin or normal saline placebo, in addition to cefazolin prophylaxis. The primary outcome was surgical-site infection within 90 days after surgery. RESULTS: A total of 4239 patients underwent randomization. Among 4113 patients in the modified intention-to-treat population (2233 undergoing knee arthroplasty, 1850 undergoing hip arthroplasty, and 30 undergoing shoulder arthroplasty), surgical-site infections occurred in 91 of 2044 patients (4.5%) in the vancomycin group and in 72 of 2069 patients (3.5%) in the placebo group (relative risk, 1.28; 95% confidence interval [CI], 0.94 to 1.73; P = 0.11). Among patients undergoing knee arthroplasty, surgical-site infections occurred in 63 of 1109 patients (5.7%) in the vancomyin group and in 42 of 1124 patients (3.7%) in the placebo group (relative risk, 1.52; 95% CI, 1.04 to 2.23). Among patients undergoing hip arthroplasty, surgical-site infections occurred in 28 of 920 patients (3.0%) in the vancomyin group and in 29 of 930 patients (3.1%) in the placebo group (relative risk, 0.98; 95% CI, 0.59 to 1.63). Adverse events occurred in 35 of 2010 patients (1.7%) in the vancomycin group and in 35 of 2030 patients (1.7%) in the placebo group, including hypersensitivity reactions in 24 of 2010 patients (1.2%) and 11 of 2030 patients (0.5%), respectively (relative risk, 2.20; 95% CI, 1.08 to 4.49), and acute kidney injury in 42 of 2010 patients (2.1%) and 74 of 2030 patients (3.6%), respectively (relative risk, 0.57; 95% CI, 0.39 to 0.83). CONCLUSIONS: The addition of vancomycin to cefazolin prophylaxis was not superior to placebo for the prevention of surgical-site infections in arthroplasty among patients without known MRSA colonization. (Funded by the Australian National Health and Medical Research Council; Australian New Zealand Clinical Trials Registry number, ACTRN12618000642280.).

Plasma and tissue concentrations of 2 g prophylactic cefazolin prior to lower extremity surgery.

Surgical site infections (SSIs) are among the most clinically relevant complications and the use of prophylactic cefazolin is common practice. However, the knowledge about the pharmacological aspects of prophylactic cefazolin in the lower extremities remains limited. In this prospective cohort, a sub-study of the WIFI-2 randomized controlled trial, adults between 18 and 75 years of age who were scheduled for implant removal below the level of the knee and randomized for cefazolin, was included. A maximum of two venous plasma, target-site plasma, and target-site tissue samples were taken during surgery. The primary outcomes were the cefazolin concentrations in venous plasma, target-site plasma, and target-site tissue. A total of 27 patients [median (interquartile range) age, 42 (29-59) years; 17 (63%) male] with 138 samples were included in the study. A minimum of 6 weeks follow-up was available for all patients. The mean (SD) venous plasma, target-site plasma, and target-site tissue concentrations were 36 (13) µg/mL, 29 (13) µg/mL, and 28 (13) µg/g, respectively, and the cefazolin concentrations between the different locations of surgery did not differ significantly in both target-site plasma and target-site tissue (P = 0.822 and P = 0.840). In conclusion, 2 g of prophylactic cefazolin demonstrates adequacy in maintaining coverage for a duration of at least 80 minutes of surgery below the level of the knee, significantly surpassing the MIC90 required to combat the most prevalent microorganisms. This study represents the first of its kind to assess cefazolin concentrations in the lower extremities by examining both plasma and tissue samples in this magnitude.

Genomic investigation and clinical correlates of the in vitro ß-lactam: NaHCO3 responsiveness phenotype among methicillin-resistant Staphylococcus aureus isolates from a randomized clinical trial.

NaHCO3 responsiveness is a novel phenotype where some methicillin-resistant Staphylococcus aureus (MRSA) isolates exhibit significantly lower minimal inhibitory concentrations (MIC) to oxacillin and/or cefazolin in the presence of NaHCO3. NaHCO3 responsiveness correlated with treatment response to ß-lactams in an endocarditis animal model. We investigated whether treatment of NaHCO3-responsive strains with ß-lactams was associated with faster clearance of bacteremia. The CAMERA2 trial (Combination Antibiotics for Methicillin-Resistant Staphylococcus aureus) randomly assigned participants with MRSA bloodstream infections to standard therapy, or to standard therapy plus an anti-staphylococcal ß-lactam (combination therapy). For 117 CAMERA2 MRSA isolates, we determined by broth microdilution the MIC of cefazolin and oxacillin, with and without 44 mM of NaHCO3. Isolates exhibiting ≥4-fold decrease in the MIC to cefazolin or oxacillin in the presence of NaHCO3 were considered "NaHCO3-responsive" to that agent. We compared the rate of persistent bacteremia among participants who had infections caused by NaHCO3-responsive and non-responsive strains, and that were assigned to combination treatment with a ß-lactam. Thirty-one percent (36/117) and 25% (21/85) of MRSA isolates were NaHCO3-responsive to cefazolin and oxacillin, respectively. The NaHCO3-responsive phenotype was significantly associated with sequence type 93, SCCmec type IVa, and mecA alleles with substitutions in positions -7 and -38 in the regulatory region. Among participants treated with a ß-lactam, there was no association between the NaHCO3-responsive phenotype and persistent bacteremia (cefazolin, P = 0.82; oxacillin, P = 0.81). In patients from a randomized clinical trial with MRSA bloodstream infection, isolates with an in vitro ß-lactam-NaHCO3-responsive phenotype were associated with distinctive genetic signatures, but not with a shorter duration of bacteremia among those treated with a ß-lactam.

Population pharmacokinetics and pharmacodynamic target attainment analysis of cefazolin using total and unbound serum concentration in patients with prostatectomy or nephrectomy.

The aim of this study was to analyze the population pharmacokinetics of total and unbound concentrations of prophylactic cefazolin (CFZ) in patients with prostatectomy or nephrectomy. We also aimed to calculate a pharmacodynamics target unbound concentration that exceeded the minimum inhibitory concentration (MIC), to design an effective dosing regimen. Briefly, 614 total concentration and 610 unbound concentration samples from 152 individuals were evaluated, using a nonlinear mixed-effects model. The obtained pharmacodynamics index target value reflected the probability of maintaining CFZ unbound trough concentrations exceeding MIC90, 0.5 mg/L, and MIC50, and 1.0 mg/L, to account for methicillin-susceptible Staphylococcus aureus (MSSA) or Escherichia coli. Population pharmacokinetics were estimated using a two-compartment model with nonlinear protein binding. Unbound systemic clearance (CL) was significantly associated with creatinine clearance, while the maximum protein-binding constant was significantly associated with albumin levels. The probability of achieving an unbound concentration exceeding the MIC50 for E. coli or MIC90 for MSSA in a patient with normal renal function following a 1 g CFZ infusion over 15 min was above 90% at 3 h after the initial dose. Our findings indicated that population pharmacokinetic parameters are useful for determining unbound CFZ pharmacokinetics and evaluating intraoperative CFZ redosing intervals.

Antimicrobial Prophylaxis With Ampicillin-sulbactam Compared With Cefazolin for Esophagectomy: Nationwide Inpatient Database Study in Japan.

OBJECTIVE: To assess the effect of antimicrobial prophylaxis with ampicillin-sulbactam (ABPC/SBT) compared with cefazolin (CEZ) on the short-term outcomes after esophagectomy. BACKGROUND: CEZ is widely used for antimicrobial prophylaxis in esophagectomy without procedure-specific evidence, whereas ABPC/SBT is preferred in some hospitals to target both aerobic and anaerobic oral bacteria. METHODS: Data of patients who underwent esophagectomy for cancer between July 2010 and March 2019 were extracted from a nationwide Japanese inpatient database. Overlap propensity score weighting was conducted to compare the short-term outcomes [including surgical site infection (SSI), anastomotic leakage, and respiratory failure] between antimicrobial prophylaxis with CEZ and ABPC/SBT after adjusting for potential confounders. Sensitivity analyses were also performed using propensity score matching and instrumental variable analyses. RESULTS: Among 17,772 eligible patients, 16,077 (90.5%) and 1695 (9.5%) patients were administered CEZ and ABPC/SBT, respectively. SSI, anastomotic leakage, and respiratory failure occurred in 2971 (16.7%), 2604 (14.7%), and 2754 patients (15.5%), respectively. After overlap weighting, ABPC/SBT was significantly associated with a reduction in SSI [odds ratio 0.51 (95% CI: 0.43-0.60)], anastomotic leakage [0.51 (0.43-0.61)], and respiratory failure [0.66 (0.57-0.77)]. ABPC/SBT was also associated with reduced respiratory complications, postoperative length of stay, and total hospitalization costs. The proportion of Clostridioides difficile colitis and noninfectious complications did not differ between the groups. Propensity score matching and instrumental variable analyses demonstrated equivalent results. CONCLUSIONS: The administration of ABPC/SBT as antimicrobial prophylaxis for esophagectomy was associated with better short-term postoperative outcomes compared with CEZ.

Cefazolin as a predictor of urinary cephalosporin activity in indicated Enterobacterales.

Traditionally, cephalothin susceptibility results were used to predict the susceptibility of additional cephalosporins; however, in 2013-2014, the Clinical and Laboratory Standards Institute (CLSI) revisited this practice and determined that cefazolin is a more accurate proxy than cephalothin for uncomplicated urinary tract infections (uUTIs). Therefore, a cefazolin surrogacy breakpoint was established to predict the susceptibility of seven oral cephalosporins for Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis in the context of uUTIs. Clinical microbiology laboratories face several operational challenges when implementing the cefazolin surrogacy breakpoint, which may lead to confusion for the best path forward. Here, we review the historical context and data behind the surrogacy breakpoints, review PK/PD profiles for oral cephalosporins, discuss challenges in deploying the breakpoint, and highlight the limited clinical outcome data in this space.

Comparing cefazolin/ metronidazole, piperacillin-tazobactam, or c efoxitin as surgical antibiotic prophylaxis in patients undergoing pancreaticoduodenectomy: A retrospective cohort study.

BACKGROUND: Preoperative antibiotic options for pancreaticoduodenectomy (PD) include cefoxitin (CX), piperacillin-tazobactam (PT), or combined cefazolin and metronidazole (CM). Recent studies suggest the superiority of PT over CX, but evidence for CM is unclear. OBJECTIVE: To explore the impact of preoperative antibiotic selection (CM vs. PT and CX vs. PT) on the development of surgical site infections (SSI). METHODS: Consecutive adult patients at one institution who underwent PD from November 2017 to December 2021 and received either CM, PT, or CX preoperatively, were included. The primary outcome was SSI. Secondary outcomes included postoperative infections and clinically significant postoperative pancreatic fistula (POPF). Logistic regression models were used. RESULTS: Among 127 patients included in the study, PT, CM, and CX were administered in 46 (36.2%), 44 (34.6%), and 37 (29.4%) patients, respectively. There were 32 (27.1%) SSI, 20 (36.1%) infections, and 21 (22.9%) POPF events. PT use was associated with reduced risk of SSI compared to CX (OR: 0.32, 95% CI: 0.11-0.89, p = 0.03), but there was no difference as compared to CM (OR: 0.75, 95% CI: 0.27-2.13, p = 0.59). There were no differences in secondary outcomes. CONCLUSION: PT reduced SSI rates compared to CX but was no different to CM among patients undergoing PD at our center.

Flucloxacillin and cefazolin for treatment of Staphylococcus aureus bloodstream infection.

PURPOSE: Antistaphylococcal penicillins and cefazolin have been used as first line therapy in Methicillin-susceptible Staphylococcus aureus bloodstream infection. While efficacy of both regimens seems to be similar, the compounds may differ with regard to tolerability. This study aims to describe the clinical use of cefazolin and flucloxacillin, focussing on discontinuation or change of anti-infective agent due to adverse events. METHODS: This observational prospective study was conducted at two German tertiary care centres with an internal recommendation of flucloxacillin for MSSA-BSI in one, and of cefazolin in the other centre. Adverse events were registered weekly under treatment and at a 90-day follow-up. Descriptive analysis was complemented by a propensity score analysis comparing adverse events (stratified rank-based test applied to the sum of Common Terminology Criteria for adverse events ratings per patient). RESULTS: Of 71 patients included, therapy was initiated with flucloxacillin in 56 (79%), and with cefazolin in 15 (21%). The propensity score analysis indicates a statistically significant difference concerning the severity of adverse events between the treatment groups in favour of cefazolin (p = 0.019). Adverse events led to discontinuation of flucloxacillin in 7 individuals (13% of all patients receiving flucloxacillin). Clinical outcome was not different among treatment groups. CONCLUSION: Using cefazolin rather than flucloxacillin as a first line agent for treatment of MSSA-BSI is supported by these clinical data.

Intraperitoneal vancomycin plus levofloxacin for the treatment of peritoneal dialysis-related peritonitis in patients with no response to cefazolin plus ceftazidime.

INTRODUCTION: Peritoneal dialysis-related peritonitis (PDRP) should be treated as soon as possible by an empirical regimen without waiting for effluent bacterial culture results. We retrospectively investigated patients treated with vancomycin plus levofloxacin as a treatment regimen if there was no response to cefazolin plus ceftazidime. MATERIALS AND METHODS: We collected records of adult patients with PDRP from January 1, 2013, to November 30, 2020. The characteristics of episodes of PDRP with no response to cefazolin plus ceftazidime treated by intraperitoneal (IP) injection of vancomycin plus levofloxacin were analyzed. RESULTS: 118 episodes of PDRP were recorded, among which 115 episodes were treated with IP antibiotics. 93 episodes were treated with cefazolin plus ceftazidime. In 38 episodes, treatment was switched to IP injection of vancomycin plus levofloxacin if there was no response to cefazolin plus ceftazidime. 26/38 (68.4%) episodes were cured by vancomycin plus levofloxacin. Fever, diabetes, fasting glucose, a decrease in effluent leukocytes on day 3 and day 5, and Charlson Comorbidity Index (CCI) scores were significantly different between uncured and cured episodes. No variable was associated with treatment failure after multiple logistic regression. Fever, diabetes, a decrease in effluent leukocytes on day 3, and CCI score were associated with treatment failure after univariable logistic regression. CONCLUSION: Vancomycin plus levofloxacin may be effective if patients are not responsive to cefazolin plus ceftazidime.

Prolonged efficacy of cefazolin in intraosseous regional prophylaxis for total knee arthroplasty: a rabbit model study.

BACKGROUND: A novel approach known as intraosseous regional administration (IORA) has emerged as a technique for delivering prophylactic antibiotics, and it results in higher tissue concentrations around the knee. It is hypothesized that IORA of cefazolin for antibiotic prophylaxis during total knee arthroplasty will result in sustained effective levels for a longer duration. The aim of the current study was to investigate temporal changes in peri-knee cefazolin blood concentrations after IORA of cefazolin. METHODS: Twelve rabbits were randomly divided into two groups, with six rabbits in each group. In control group a single intravenous bolus injection of cefazolin (10 mL, 100 mg) was administered into the marginal ear vein. In experimental groupexperimental group the same dose of cefazolin was injected into the left tibial marrow cavity after tourniquet inflation at the base of the left thigh. Blood samples were collected periodically at different timepoints, and cefazolin concentrations were determined. RESULTS: The intraosseous treatment resulted in significant differences in plasma cefazolin concentrations at all timepoints. Experimental group exhibited higher plasma cefazolin concentrations than control group. CONCLUSIONS: Cefazolin in intraosseous regional prophylaxis exhibits effectiveness in intraoperative antibiotic prophylaxis by maintaining concentrations above the minimum inhibitory concentration for extended durations, rather than relying solely on high concentrations.

Comparison of the effect between cefazolin/cefuroxime and broad-spectrum antibiotics in preventing post-operative pulmonary infections for smoking patients receiving video-assisted thoracoscopic lung surgery: a propensity score-matched retrospective cohort study.

BACKGROUND: The selection of prophylactic antibiotics for preventing post-operative pulmonary infections in smoking patients undergoing video-assisted thoracoscopic lung surgery (VATLS) is not clear. METHODS: In this retrospective cohort study, the outcomes of 572 smoking patients undergoing VATLS with prophylactic cefazolin/cefuroxime or other antibiotics were analyzed. Patients were classified as cefazolin/cefuroxime group and the control group. A 1:1 propensity score matching was also performed. RESULTS: The primary outcome of the incidence of post-operative pulmonary infection did not differ significantly between the two groups (23.7% vs 30.5%, RR = 0.777, 95%CI 0.564 ~ 1.070 p = 0.113). Similarly, secondary outcomes including the incidence of post-operative fever, the white blood cell count and neutrophils on the 3rd day after the surgery, and time for blood routine test recovery were all found without significant difference between the two groups. In the multivariate logistic regression model, no association was found between prophylactic use of cefazolin/cefuroxime and post-operative pulmonary infections after controlling other possible confounding factors (OR = 0.685, 95%CI 0.441 ~ 1.065, p = 0.093). CONCLUSIONS: Prophylactic use of cefazolin/cefuroxime was not associated with more adverse clinical outcomes among smoking populations undergoing VATLS when compared with broad-spectrum antibiotics and the two drugs are still feasible for peri-operative prophylactic use for smoking population before the surgery.

Non-cefazolin antibiotic prophylaxis is associated with higher rates of elbow periprosthetic joint infection.

BACKGROUND: Periprosthetic joint infection (PJI) is a common source of failure following elbow arthroplasty. Perioperative prophylactic antibiotics are considered standard of care. However, there are no data regarding the comparative efficacy of various antibiotics in the prevention of PJI for elbow arthroplasty. Previous studies in shoulder, hip, and knee arthroplasty have demonstrated higher rates of PJI with administration of non-cefazolin antibiotics. The elbow has higher rates of PJI than other joints. Therefore, this study evaluated whether perioperative antibiotic choice affects rates of PJI in elbow arthroplasty. MATERIALS AND METHODS: A single-institution, prospectively collected total joint registry database was queried to identify patients who underwent primary elbow arthroplasty between 2003 and 2021. Elbows with known infection prior to arthroplasty (25) and procedures with incomplete perioperative antibiotic data (7) were excluded, for a final sample size of 603 total elbow arthroplasties and 19 distal humerus hemiarthroplasties. Cefazolin was administered in 561 elbows (90%) and non-cefazolin antibiotics including vancomycin (32 elbows, 5%), clindamycin (27 elbows, 4%), and piperacillin/tazobactam (2 elbows, 0.3%) were administered in the remaining 61 elbows (10%). Univariate and multivariate analyses were conducted to determine the association between the antibiotic administered and the development of PJI. Infection-free survivorship was estimated using the Kaplan-Meier method. RESULTS: Deep infection occurred in 47 elbows (7.5%), and 16 elbows (2.5%) were diagnosed with superficial infections. Univariate analysis demonstrated that patients receiving non-cefazolin alternatives were at significantly higher risk for any infection (hazard ratio [HR] 2.6, 95% confidence interval [CI] 1.4-5.0; P < .01) and deep infection (HR 2.7, 95% CI 1.3-5.5; P < .01) compared with cefazolin administration. Multivariable analysis, controlling for several independent predictors of PJI (tobacco use, male sex, surgical indication other than osteoarthritis, and American Society of Anesthesiologists score), showed that non-cefazolin administration had a higher risk for any infection (HR 2.8, 95% CI 1.4-5.3; P < .01) and deep infection (HR 2.9, 95% CI 1.3-6.3; P < .01). Survivorship free of infection was significantly higher at all time points for the cefazolin cohort. DISCUSSION: In primary elbow arthroplasty, cefazolin administration was associated with significantly lower rates of PJI compared to non-cefazolin antibiotics, even in patients with a greater number of prior surgeries, which is known to increase the risk of PJI. For patients with penicillin or cephalosporin allergies, preoperative allergy testing or a cefazolin test dose should be considered before administering non-cefazolin alternatives.

Effect of prophylactic use of cefazolin in caesarean section on postoperative infection: A meta-analysis.

Caesarean section rate is increasing and postoperative wound infection is a major health-threatening complication after caesarean section (CS). The aim of this study was to evaluate the efficacy of Cefazolin at different time for post-caesarean delivery. The aim of this study was to compare the use of Cefazolin at different times on infections after CS. The time of antibiotic use in CS can be divided into two groups: before skin incision (SI) and after cord clamping (CC). In this study, 268 relevant articles were found in the database, and finally, 10 articles were analysed. This study included a total of 5256 cases of caesarean section. The data on wound infections, endometritis, urinary tract infections and fever were analysed. Perform an analysis of the data using RevMan 5.3. The results showed that cefazolin before SI reduced wound infection compared to after CC (odds ratio [OR], 0.51; 95% CI: 0.37-0.69; p < 0.0001). Cefazolin prophylactically used before SI reduce endometritis after CS compared to after CC (OR, 0.52; 95% CI: 0.35-0.77; p = 0.001). There was no significant difference in urinary tract infections after CS between cefazolin prophylactically used before SI and after CC (OR, 0.80; 95% CI: 0.50-11.28; p = 0.35). There was no significant difference in fever after CS between the prophylactic use of cefazolin before SI and after CC (OR, 0.60; 95% CI: 0.26-11.43; p = 0.225). Cefazolin before SI reduces wound infection and endometritis after CS.

Adherence to Antimicrobial Prophylaxis Guidelines for Elective Surgeries Across 825 US Hospitals, 2019-2020.

BACKGROUND: There are limited US data assessing adherence to surgical antimicrobial prophylaxis guidelines, particularly across a large, nationwide sample. Moreover, commonly prescribed inappropriate antimicrobial prophylaxis regimens remain unknown, hindering improvement initiatives. METHODS: We conducted a retrospective cohort study of adults who underwent elective craniotomy, hip replacement, knee replacement, spinal procedure, or hernia repair in 2019-2020 at hospitals in the PINC AI (Premier) Healthcare Database. We evaluated adherence of prophylaxis regimens, with respect to antimicrobial agents endorsed in the American Society of Health-System Pharmacist guidelines, accounting for patient antibiotic allergy and methicillin-resistant Staphylococcus aureus colonization status. We used multivariable logistic regression with random effects by hospital to evaluate associations between patient, procedural, and hospital characteristics and guideline adherence. RESULTS: Across 825 hospitals and 521 091 inpatient elective surgeries, 308 760 (59%) were adherent to prophylaxis guidelines. In adjusted analysis, adherence varied significantly by US Census division (adjusted OR [aOR] range: .61-1.61) and was significantly lower in 2020 compared with 2019 (aOR: .92; 95% CI: .91-.94; P < .001). The most common reason for nonadherence was unnecessary vancomycin use. In a post hoc analysis, controlling for patient age, comorbidities, other nephrotoxic agent use, and patient and procedure characteristics, patients receiving cefazolin plus vancomycin had 19% higher odds of acute kidney injury (AKI) compared with patients receiving cefazolin alone (aOR: 1.19; 95% CI: 1.11-1.27; P < .001). CONCLUSIONS: Adherence to antimicrobial prophylaxis guidelines remains suboptimal, largely driven by unnecessary vancomycin use, which may increase the risk of AKI. Adherence decreased in the first year of the COVID-19 pandemic.

Retrospective Evaluation of the Association of Oxacillin MIC on Acute Treatment Outcomes with Cefazolin and Antistaphylococcal Penicillins in Methicillin-Susceptible Staphylococcus aureus Bacteremia.

Antistaphylococcal penicillins (ASP) and cefazolin are first-line treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. Borderline oxacillin resistance (i.e., oxacillin MICs 1-8 µg/mL) is observed in strains hyperproducing beta-lactamases. This mechanism is also behind the proposed inoculum effect. Minimal data exists on the comparative efficacy of cefazolin or ASP in qualitatively susceptible strains that demonstrate MICs of oxacillin of 1 to 2 µg/mL compared to strains with MIC of oxacillin < 1 µg/mL. We performed a retrospective cohort study of acute treatment outcomes in adult patients with community-acquired MSSA bacteremia treated with cefazolin or ASP, stratified by oxacillin MIC. The primary outcome was a composite of all-cause mortality during the index inpatient admission, failure to clear blood cultures within 72 h after initiating definitive therapy, and change in therapy due to perceived lack of efficacy. A total of 402 patients were included in this study, including 226 isolates with an oxacillin MIC ≥ 1 µg/mL and 176 isolates with an MIC < 1 µg/mL. There were no differences in the rate of the primary outcome occurrence between patients with an oxacillin MIC ≥ 1 µg/mL and an MIC < 1 µg/mL (16.4% versus 15.9%, P = 0.90). There was no difference in the primary outcome between high versus low oxacillin MIC groups among those who received ASP (22.9% versus 24.1%, P = 0.86) or cefazolin (10.3% versus 11.9%, P = 0.86). In our cohort of patients with MSSA bacteremia, oxacillin MIC (i.e., ≥ 1 versus < 1 µg/mL) was not associated with acute treatment outcomes, regardless of the beta-lactam selected as definitive therapy.

Using antibiotics wisely.

PURPOSE OF REVIEW: This review will describe role of shorter antibiotic therapies, early switch from intravenous to oral therapy, and artificial intelligence in infectious diseases. RECENT FINDINGS: There is evidence that shorter courses of antibiotics are noninferior to standard durations of therapy. This has been demonstrated with Enterobacterales bacteremia that can be treated with 7 days of therapy, community acquired pneumonia with 3 days and ventilator associated pneumonia with just 7 days of antibiotic therapy. The conversion from intravenous to oral therapy in treating bacteremia, endocarditis and bone and joint infections is safe and effective and reduces line complications and costs. Also, for clean surgical procedures only one dose of antibiotic is needed, but it should be the most effective antibiotic which is cefazolin. This means avoiding clindamycin, removing penicillin allergies where possible for improved outcomes. Finally, the role of artificial intelligence to incorporate into using antibiotics wisely is rapidly emerging but is still in early stages. SUMMARY: In using antibiotics wisely, targeting such as durations of therapy and conversion from intravenous antibiotic therapy to oral are low hanging fruit. The future of artificial intelligence could automate a lot of this work and is exciting but needs to be proven. VIDEO ABSTRACT: http://links.lww.com/COID/A50.

Post-treatment outcomes of ceftriaxone versus antistaphylococcal penicillins or cefazolin for definitive therapy of methicillin-susceptible Staphylococcus aureus bacteremia.

Methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia is associated with poor outcomes. Ceftriaxone offers logistical advantages over other standard therapies, though in vitro studies have questioned its efficacy and clinical studies of ceftriaxone in MSSA bacteremia are conflicting.We performed a multicenter, retrospective cohort study of adult patients who received ceftriaxone, cefazolin, or antistaphylococcal penicillins as definitive therapy for MSSA bacteremia from 2018 to 2019. Definitive therapy was defined as the antibiotic used in the outpatient setting. Patients were excluded if they received less than 7 days of outpatient therapy. Follow-up started on the date of definitive therapy completion. The primary outcome was 90-day treatment failure, defined as a composite of mortality and microbiologic recurrence. This was analyzed with multivariable Cox regression. A total of 223 patients were included, 37 (16.6%) of whom received ceftriaxone. The most common ceftriaxone dose was 2 g daily (83.8%). The most common primary site of infection was skin/soft tissue (37.2%), unknown (21.1%), and catheter-related (15.2%). Twenty-six (11.7%) developed infective endocarditis. Median total duration of treatment was 31.0 days, and median outpatient duration was 24.0 days. Twenty-six (11.7%) developed 90-day treatment failure. After adjusting for Charlson comorbidity index, duration of therapy, and use of transesophageal echocardiography, definitive treatment with ceftriaxone was associated with treatment failure (hazard ratio 2.66, 95% confidence interval 1.15-6.12; p=0.022). Among patients with MSSA bacteremia, definitive treatment with ceftriaxone was associated with a higher risk of treatment failure within 90 days as compared to cefazolin or antistaphylococcal penicillins.

Comparison of Cefazolin and Ceftriaxone as Antimicrobial Prophylaxis in Pancreatoduodenectomy with Preoperative Drainage: Incidence of Surgical Site Infection and Susceptibility of Bacteria in Bile.

BACKGROUND: The optimal perioperative antimicrobial agent for preventing surgical site infection (SSI) in pancreatoduodenectomy (PD) with preoperative biliary drainage (PBD) remains unclear. METHODS: We retrospectively reviewed 288 patients who underwent PD after PBD between 2010 and 2020 at our institution. Patients were classified into two groups according to the perioperative antimicrobial agent used (cefazoline [CEZ] group [n = 108] and ceftriaxone [CTRX] group [n = 180]). The incidence of SSI, type of bacteria in intraoperative bile culture (IBC), and antimicrobial susceptibility to prophylactic antimicrobial agents were analyzed. RESULTS: The incidence of incisional SSI was significantly lower in the CTRX group than in the CEZ group (18% vs. 31%, P = 0.021), whereas the incidence of organ/space SSI in the two groups did not differ to a statistically significant extent (35% vs. 44%, P = 0.133). Gram-negative rod (GNR) bacteria in the IBC showed better antimicrobial susceptibility in the CTRX group than in the CEZ group. In multivariate analysis, antimicrobial resistance due to GNR was a significant risk factor for incisional SSI (odds ratio, 3.50; P < 0.001). CONCLUSIONS: CTRX had better antimicrobial coverage than CEZ for GNR cultured from intraoperative bile samples. In addition, CTRX provides better antimicrobial prophylaxis than CEZ against superficial SSI in patients with PD after PBD. TRIAL REGISTRATION NUMBER: This study was not a clinical trial and had no registration numbers.

MIC Discrepancies between Parenteral and Oral Anti-Staphylococcal Beta-Lactams among MSSA.

INTRODUCTION: Recent evidence has shown that oral antibiotic therapy is not inferior to IV antibiotic therapy in the treatment of complicated Staphylococcus aureus infections. Therefore, oral antibiotic therapy is now frequently prescribed in clinical practice due to cost benefit, ease of administration, decreased complication rate, and lack of need for IV access. In vitro susceptibility testing for ß-lactam oral antibiotics is not routinely performed as the guidelines provided by the Clinical and Laboratory Standards Institute (CLSI) recommend using oxacillin and cefoxitin as surrogate markers. Hence, oral antibiotic susceptibilities for cephalexin and dicloxacillin are not reported and implied based on oxacillin and cefoxitin. The objective of the current study was to determine whether susceptibilities among S. aureus isolates are predictable when comparing commonly used IV and oral beta-lactams. METHODS: Cefazolin, cephalexin, dicloxacillin, and oxacillin broth microdilution minimum inhibitory concentrations (MICs) were determined for 100 clinical isolates of methicillin-sensitive S. aureus by broth microdilution following CLSI guidelines. RESULTS: Among these isolates, median MICs for cephalexin were eight-fold higher than cefazolin MICs and median MICs for dicloxacillin were four-fold less than oxacillin MICs. Ten percent of more strains studied had a major or very major error in its susceptibility reporting when cephalexin was compared to its surrogate marker oxacillin. DISCUSSIONS/CONCLUSIONS: The variations in MICs observed compounded with the dosing and pharmacokinetic differences of oral versus IV ß-lactam suggests that establishing breakpoints for oral ß-lactam antibiotics is necessary to ensure adequate therapy is selected for the treatment of complex S. aureus infections.

Metronidazole for Prevention of Pelvic Cellulitis and Abscess after Laparoscopic Hysterectomy: A Triple-blinded, Randomized, Placebo-controlled Clinical Trial.

STUDY OBJECTIVE: To determine whether a postoperative 5-day treatment schedule with vaginal metronidazole added to conventional antibiotic prophylaxis with 2 g cefazolin modifies the risk of pelvic cellulitis (PC) and pelvic abscess (PA) after total laparoscopic hysterectomy (TLH). DESIGN: A randomized, controlled, triple-blind, multicenter clinical trial. SETTING: Two centers dedicated to minimally invasive gynecologic surgery in Colombia. PATIENTS: A total of 574 patients were taken to TLH because of benign diseases. INTERVENTION: Patients taken to TLH were divided into 2 groups (treatment group, cefazolin 2 g intravenous single dose before surgery + metronidazole vaginal ovules for 5 days postoperatively, control group: cefazolin 2 g intravenous single dose + placebo vaginal ovules for 5 days postoperatively). MEASUREMENTS AND MAIN RESULTS: The absolute frequency (AF) of PC and PA and their relationship with the presence of bacterial vaginosis (BV) were measured. There was no difference in AF of PC (AF, 2/285 [0.7%] vs 5/284 [1.7%] in the treatment and placebo groups, respectively; risk ratio, 1.75; 95% confidence interval, 0.54-5.65; p = .261), nor for PA (AF, 0/285 [0%] vs 2/289 [0.7%]; p = .159, in the treatment and placebo groups, respectively). The incidence of BV was higher in the metronidazole group than the placebo group (42.5% vs 33.4%, p = .026). CONCLUSION: The use of vaginal metronidazole ovules during the first 5 days in postoperative TLH added to conventional cefazolin prophylaxis does not prevent the development of PC or PA, regardless of the patient's diagnosis of BV.