Aims: The present study was conducted to investigate the mechanism of carbapenem resistance and the molecular epidemiology of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates collected from two nearby hospitals in Tehran, Iran. Methods and Results: A total of 180 CRAB isolates were studied. Antimicrobial susceptibility testing was performed using disk diffusion and Epsilometer tests. The detection of OXA-23, -24 and -58 was implemented for all isolates using polymerase chain reaction. Subsequently, isolates harbouring OXA-24 and -58 were investigated for the presence of resistance determinants of Ambler class A, metallo-b-lactamases (MBLs), and carbapenem-hydrolysing class D b-lactamases, ISAba1, and the genetic relatedness between them was analysed using pulsed-field gel electrophoresis (PFGE). All isolates were found to be resistant to imipenem with a MIC of ≥8 µg ml À1 and were susceptible to colistin with a MIC of ≤1Á5 µg ml À1 . Sixty percent of the isolates had OXA-23. OXA-24 and -58 were detected in 31 of 180 CRAB isolates. These chosen isolates were devoid of MBLs and bla SHV , bla CTX-M , bla VEB ESBL genes. The PER determinant was detected in 38% of isolates as the most common extended spectrum b-lactamases (ESBLs). Of these isolates, 51Á6% had OXA-23, and ISAba1 was found to be upstream of OXA-23 and OXA-51 in 16 and 8 isolates, respectively. The band patterns produced by PFGE showed nine clonal pulsotypes distributed between the two hospitals. Conclusion: The findings showed that the refractory CRAB isolates were transmitted intra-and inter-hospital, particularly in the ICU due to shortcomings in infection control surveillance. Significance and Impact of the Study: Carbapenem resistance is a substantial threat in the treatment of infections caused by A. baumannii due to limitations in the therapeutic options.

The purpose of this study was to compare the effectiveness of Atazanavir/Ritonavir/Dolutegravir/Hydroxychloroquine and Lopinavir/Ritonavir/Hydroxychloroquine treatment regimens in COVID‐19 patients based on clinical and laboratory parameters. We prospectively evaluated the clinical and laboratory outcomes of 62 moderate to severe COVID‐19 patients during a 10‐day treatment plan. Patients were randomly assigned to either KH (receiving Lopinavir/Ritonavir [Kaletra] plus Hydroxychloroquine) or ADH (receiving Atazanavir/Ritonavir, Dolutegravir, and Hydroxychloroquine) groups. During this period, clinical and laboratory parameters and outcomes such as intensive care unit (ICU) admission or mortality rate were recorded. Compared to the KH group, after the treatment period, patients in the ADH group had higher activated partial thromboplastin time (aPTT) (12, [95% confidence interval [CI]: 6.97, 17.06), p = <0.01), international normalized ratio (INR) (0.17, [95% CI: 0.07, 0.27), p = <0.01) and lower C‐reactive protein (CRP) (−14.29, (95% CI: −26.87, −1.71), p = 0.03) and potassium (−0.53, (95% CI: −1.03, −0.03), p = 0.04) values. Moreover, a higher number of patients in the KH group needed invasive ventilation (6 (20%) vs. 1 (3.1%), p = 0.05) and antibiotic administration (27 (90%) vs. 21(65.6), p = 0.02) during hospitalization while patients in the ADH group needed more corticosteroid administration (9 (28.1%) vs. 2 (6.7%), p = 0.03). There was no difference in mortality rate, ICU admission rate, and hospitalization period between the study groups. Our results suggest that the Atazanavir/Dolutegravir treatment regimen may result in a less severe disease course compared to the Lopinavir/Ritonavir treatment regimen and can be considered as an alternative treatment option beside standard care. However, to confirm our results, larger‐scale studies are recommended.

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Background: It is unclear which the material is a better choice for post and core rehabilitation systems in endodontically treated teeth. This study aimed to compare the fracture resistance of three different postcore systems. Materials and Methods: In this in vitro study, 33 extracted premolars were treated endodontically and divided into three groups, namely (A) the prefabricated fiberglass postcomposite core, (B) the Ni-Cr cast postcore, and (C) the polyetheretherketone (PEEK) postcore groups. After postcementation, the core was restored with Ni-Cr crown. By a universal testing machine, the fracture resistance of the posts was assessed. Furthermore, types of fractures were determined with radiography and confirmed objectively by cutting the acryl resin boxes. The data of the fracture resistance were analyzed using the one-way ANOVA and Tukey test, and the data of the fracture pattern were analyzed using Fisher's exact test ( P < 0.05). Results: The fracture resistance was significantly higher in Group B (Ni-Cr) than in Group C (PEEK) ( P = 0.001) and Group A (fiberglass) ( P < 0.001). Moreover, the fracture resistance was higher in Group C (PEEK) than in Group A (fiberglass) but was not statistically significant ( P = 0.405). The fracture pattern was different in all the groups based on the types of fracture ( P = 0.009) and the repairability of fracture ( P = 0.036). Conclusion: The present study showed that the fracture resistance was significantly higher in the Ni-Cr post than in the fiberglass and PEEK posts. Further, the fracture mode was more repairable in teeth restored with the PEEK post, as compared to the other posts.