Virulence potential of multidrug-resistant Acinetobacter baumannii isolates from COVID-19 patients on mechanical ventilation: The first report from Serbia

Abstract

Since the WHO declared the COVID-19 pandemic in March 2020, the disease has spread rapidly leading to overload of the health system and many of the patients infected with SARS-CoV-2 needed to be admitted to the intensive care unit (ICU). Around 10% of patients with the severe manifestation of COVID-19 need noninvasive or invasive mechanical ventilation, which represent a risk factor for Acinetobacter baumannii superinfection. The 64 A. baumannii isolates were recovered from COVID-19 patients admitted to ICU at General Hospital “Dr Laza K. Lazarević” Šabac, Serbia, during the period from December 2020 to February 2021. All patients required mechanical ventilation and mortality rate was 100%. The goal of this study was to evaluate antibiotic resistance profiles and virulence potential of A. baumannii isolates recovered from patients with severe form of COVID-19 who had a need for mechanical ventilation. All tested A. baumannii isolates (n = 64) were sensitive to colistin, while resistant to meropenem, imipenem, gentamicin, tobramycin, and levofloxacin according to the broth microdilution method and MDR phenotype was confirmed. In all tested isolates, representatives of international clone 2 (IC2) classified by multiplex PCR for clonal lineage identification, blaAmpC, blaOXA-51, and blaOXA-23 genes were present, as well as ISAba1 insertion sequence upstream of blaOXA-23. Clonal distribution of one dominant strain was found, but individual strains showed phenotypic differences in the level of antibiotic resistance, biofilm formation, and binding to mucin and motility. According to PFGE, four isolates were sequenced and antibiotic resistance genes as well as virulence factors genes were analyzed in these genomes. The results of this study represent the first report on virulence potential of MDR A. baumannii from hospital in Serbia.

The Impact of Acinetobacter baumannii Infections in COVID-19 Patients Admitted in Hospital Intensive Care Units

“…Despite identifying a predominant pulsotype through PFGE analysis, individual A. baumannii strains exhibited variations in antibiotic resistance, biofilm formation, binding to mucin, and motility, which may be due to horizontal gene transfer, mutations, or physiological adaptations. Hence, the study highlighted that A. baumannii isolates recovered from male patients display higher mucin adhesion ability than isolates originating from females, associated with increased bacterial virulence and poorer outcomes for affected patients [12]. In contrast, an Italian study involving 96 isolates and utilizing both short-and long-read sequencing technologies identified two endemic clones of multidrug-resistant A. baumannii responsible for a hospital outbreak during the initial wave of the COVID-19 pandemic.…”

“…Amongst the plethora of potential coinfections during the COVID-19 pandemic, the interest directed towards A. baumanii was due to the efficiency of the pathogen in avoiding antibiotic treatments coupled with the potential to take advantage of the already weakened immune system of the patients infected with the COVID-19 virus. A recent study conducted in a Serbian hospital aiming to assess the MDR profile and virulence potential of A. baumannii isolates from COVID-19 patients admitted to the ICU revealed an increased risk of developing MDR bacterial infections in patients on mechanical ventilation [12]. Therefore, antimicrobial stewardship programs are mandatory in this population.…”

Bacterial Infections in Intensive Care Units: Epidemiological and Microbiological Aspects

“…For instance, carbapenem-resistance A. baumannii (CRAB) predominates within ICUs, mostly due to blaOXA-23, blaOXA-66, and blaOXA-51 genes [ 21 ]. The mentioned resistance markers integrate an extended resistance profile, leading to the A. baumannii insertion into the alert microorganisms’ lists [ 26 ].…”