The emergence of multi-drug-resistant bacteria causing healthcare-associated infections in COVID-19 patients: a retrospective multi-centre study.

INTRODUCTION: We evaluated the prevalence, aetiologies and antibiotic resistance patterns of bacterial infections in hospitalized patients with laboratory-confirmed SARS-CoV-2. We also investigated comorbidities, risk factors and the mortality rate in COVID-19 patients with bacterial infections. METHODS: This retrospective observational study evaluated medical records of 7249 randomly selected patients with COVID-19 admitted to three clinical centres between 1st January 2021 and 16th February 2022. A total of 6478 COVID-19 patients met the eligibility criteria for analysis. RESULTS: The mean age of the patients with SARS-CoV-2 and bacterial infections was 68.6 ± 15.5 years (range: 24-94 years). The majority of patients (68.7%) were older than 65 years. The prevalence of bacterial infections among hospitalized COVID-19 patients was 12.9%, most of them being hospital-acquired (11.5%). Bloodstream (37.7%) and respiratory tract infections (25.6%) were the most common bacterial infections. Klebsiella pneumoniae and Acinetobacter baumannii caused 25.2% and 23.6% of all bacterial infections, respectively. Carbapenem-resistance in Enterobacterales, A. baumannii and Pseudomonas aeruginosa were 71.3%, 93.8% and 69.1%, respectively. Age >60 years and infections caused by ≥3 pathogens were significantly more prevalent among deceased patients compared with survivors (P<0.05). Furthermore, 95% of patients who were intubated developed ventilator-associated pneumonia. The overall in-hospital mortality rate of patients with SARS-CoV-2 and bacterial infections was 51.6%, while 91.7% of patients who required invasive mechanical ventilation died. CONCLUSIONS: Our results reveal a striking association between healthcare-associated bacterial infections as an important complication of COVID-19 and fatal outcomes.

Structure and morphology of Mg-Al-Fe-mixed oxides derived from layered double hydroxides.

The influences of the nature and the extent of M(III) ion substitution on the structure, morphology and surface properties of layered double hydroxides, LDHs [Mg(1-x) M(III)(x)(OH)(2)](CO(3))(x/n).mH(2)O, M(III) being Al or/and Fe and x= M(III)/[(Mg+M(III)], and derived mixed oxides were investigated. Three series: Mg-Al, Mg-Al-Fe and Mg-Fe were synthesized using low supersaturation co-precipitation method at constant pH, with different Mg : Al : Fe ratio and x in the wide range from 0.15 to 0.7 in order to obtain complex, multi-phase systems with disordered structure, developed surface area, acid-base and redox properties favourable for catalytic application. The morphology of LDHs and their derived mixed oxides did not change considerably although pronounced changes in structural and surface properties occur by thermal decomposition. The increase in Al amount, as well as the deviation of M(III) content from the optimal range for the single LDH phase synthesis, causes the formation of smaller particles and decrease of mixed oxide crystallite size. The nature and amount of M(III) influence the development of surface area, after thermal treatment, depending mainly on the presence of smaller mesopores, not visible by scanning electron microscope. Although the particle size has no considerable influence on the value of the surface area, it was observed that the samples with smaller particles (Mg-Al and Mg-Al-Fe series) have also higher surface area compared with the samples with larger particles (Mg-Fe series).