Background The aim of this study was to compare the safety and effectiveness of ceftazidime-avibactam (CAZ-AVI) to colistin-based regimen in the treatment of infections caused by carbapenem-resistant Enterobacterales (CRE). Methods This was a retrospective, multicenter, observational cohort study of inpatients who received either CAZ-AVI or intravenous colistin for treatment of infections due to CRE. The study was conducted in 5 tertiary care hospitals in Saudi Arabia. Main study outcomes included in-hospital mortality, clinical cure at end of treatment, and acute kidney injury (AKI). Univariate analysis and multivariate logistic regression model were conducted to assess the independent impact of CAZ-AVI on the clinical outcome. Results A total of 230 patients were included in this study: 149 patients received CAZ-AVI and 81 patients received colistin-based regimen. Clinical cure (71% vs 52%; P = 0.004; OR, 2.29; 95% CI, 1.31–4.01) was significantly more common in patients who received CAZ-AVI. After adjusting the difference between the two groups, treatment with CAZ-AVI is independently associated with clinical cure (adjusted OR, 2.75; 95% CI, 1.28–5.91). In-hospital mortality (35% vs 44%; P = 0.156; OR, 0.67; 95% CI, 0.39–1.16) was lower in patients who received CAZ-AVI but the difference was not significant. AKI (15% vs 33%; P = 0.002; OR, 0.37; 95% CI, 0.19–0.69) was significantly less common in patients who received CAZ-AVI. Conclusion CAZ-AVI is associated with higher rate of clinical cure and lower rate of AKI compared to colistin. Our findings support the preferential use of CAZ-AVI over colistin-based regimen for treating these infections.

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The outcome of transplant recipients is variable depending on the study population, vaccination status and COVID-19 variants. Our aim was to study the impact of Omicron subvariants on the mortality of transplant recipients. We reviewed the results of SARS-CoV-2 whole genome sequence of random isolates collected from 29 December 2021 until 17 May 2022 in King Faisal Specialist Hospital and Research center, Jeddah (KFSHRC-J), Saudi Arabia performed as hospital genomic surveillance program for COVID-19 variants. We included 25 transplant patients infected with confirmed Omicron variants.17 (68%) and 8 (32%) patients had Omicron BA.1 and BA.2, respectively. 12 (68%) patients had renal transplants. Only 36% of patients received three doses of COVID-19 vaccines. 23 (92%) patients required hospitalization. 20 (80%) patients survived and 6 (25%) required intensive care unit (ICU) admission. Among ICU patients, 66.7% were more than 50 years, 50% had two to three comorbidities and 5 out of 6 (83%) died. The mortality of transplant patients infected with Omicron variants in our cohort was higher than other centers as a limited number of patients received booster vaccines. Optimizing booster vaccination is the most efficient method to improve the mortality of COVID-19 in transplant recipients recognizing the inefficacy of monoclonal antibodies in the presence of SARS-CoV-2 emerging variants. We did not show a difference in mortality in transplant patients infected with Omicron BA.1 and BA.2 knowing the limitation of our sample size.

Background Owing to the excellent safety and efficacy profile of the tenofovir alafenamide (TAF) over tenofovir disoproxil fumarate (TDF), it is the preferred prodrug of tenofovir (TFV) implicated in the management of people living with HIV (PLWH). PLWH are more susceptible to having tuberculosis (TB) and therefore, rifampicin (RIF) use as a key component of antituberculosis therapy is frequently indicated. However, since TAF is a substrate for drug transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) and RIF being an inducer for these transporters, the concomitant use of RIF and TAF is not recommended. The magnitude of this drug-drug interaction in PLWH is not known. Hence, the objective of this study was to Methods We retrospectively reviewed the charts of PLWH (≥ 18 years old) seen in our center and who received the TAF-containing regimens and RIF together for ≥ 4 weeks. Demographic data were described using descriptive statistics. We defined the clinical impact as the following: 1- maintaining viral suppression (< 20 copies/mL) for those with suppressed viral load at baseline, 2- the attainment of the viral load suppression (< 20 copies/mL) for those with unsuppressed viral load at baseline. The clinical impact was assessed from the RIF initiation to the end of the therapy. Results A total of 6 PLWH were identified, 5 (83.3%) of them were males. The median (IQR) age was 41.5 years old (49.25 to 36). All patients received dolutegravir 50 mg twice daily (DTG) plus the combination of TAF 25 mg and emtricitabine 200 mg (FTC) once daily as their antiretroviral regimen. Pulmonary tuberculosis was the indication for RIF in all the cases. The RIF dose of 600 mg was the most frequently prescribed (83.3%). The mean (±SD) duration of RIF-TAF co-administration was 30 weeks (2.8). Four patients had suppressed viral load levels at baseline, which was maintained throughout the course of TB treatment. Two patients had unsuppressed viral load levels at baseline and attained viral load suppression throughout the treatment course. Conclusion This case series study demonstrated the possibility of RIF-TAF co-administration, without attenuation the efficacy of TAF, however further work on a large sample is needed to confirm our findings. Disclosures All Authors: No reported disclosures.