Enormous rise in Acinetobacter bloodstream infection cases in initial two years of COVID-19

By Pooja Toshniwal PahariaNov 21 2022Reviewed by Aimee Molineux

In a recent study published in Eurosurveillance, researchers investigated Acinetobacter species bloodstream infection (BSI) case counts from a subset of laboratory data continuously reported during the initial two years of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections from 2020 to 2021.

Studies have reported poor outcomes of Acinetobacter BSIs, particularly among ICU (intensive care unit)-admitted individuals. The bacterial organism has intrinsic resistance to several antimicrobial agents, and additionally, acquired resisting abilities may further complicate treatment regimens among vulnerable individuals.

Recently published EARS-Net (European antimicrobial resistance surveillance network) data showed a significant rise in Acinetobacter BSIs among EU/ EUA (European Union/European economic area) nations between 2017 and 2021. A major fraction of the increase was found to occur in the 2020 to 2021 period, the initial years of the SARS-CoV-2 pandemic.

About the study

In the present study, researchers evaluated the increase in Acinetobacter BSIs during the initial two years of coronavirus disease 2019 (COVID-19) between 2020 and 2021.

The data analyzed in the present study originated from qualitative regular AST (antimicrobial susceptibility testing) reports of blood samples obtained by locally based laboratories in the national-level networks of EU/EEA nations. The laboratory testing results documented yearly by national-level centers to ECDC (European centre for disease prevention and control), following the EARS-Net documentation protocols, were analyzed. Only the initial isolate of every individual per year per bacterium was included in the Ears-Net data.

All European Union nations, Norway and Iceland have submitted information to the EARS-Net system each year between 2017 and 2021; however, for the present analysis, the dataset was limited to Acinetobacter BSIs data from laboratories (255 out of 826 clinical laboratories) that documented results of carbapenem (meropenem and/or imipenem) susceptibility testing for Acinetobacter species each year between 2017 and 2021.

Data were restricted to reduce bias from annual variations in hospital affiliations, number, and reporting type of laboratories since all nations could not distinguish between clinical laboratories with no documented cases and laboratories with no such cases.

Data from the UK (United Kingdom) was not included since the nation had withdrawn from the EU in 2020. Additionally, data from France was not included since only a few clinical laboratories were identifiable continuously after the reorganization of national-level surveillance in 2020. The percentages of Acinetobacter resistance varied considerably between the EU/EEA nations. Therefore, the nations were grouped based on average percentages of their national yearly carbapenem resistance reported during the 2018 to 2019 period. Poisson regression modeling was used to assess the differences in BSI counts and carbapenem resistance percentages between 2020 to 2021 and 2018 to 2019.

Results

Group 1 nations (n=13) had less than 10% resistance to carbapenem and included the Netherlands, Belgium, Austria, Estonia, Denmark, Germany, Iceland, Finland, Luxembourg, Ireland, Norway, Sweden, and Malta. Group 2 nations (n=3) had resistance to carbapenem between 10% and 50% and included Slovenia, Czechia, and Portugal. Group 3 nations (n=12) had equal to or greater than 50% resistance to carbapenem and included Croatia, Bulgaria, Greece, Cyprus, Italy, Hungary, Lithuania, Latvia, Romania, Poland, Spain, and Slovakia.

Further, the units were grouped based on the ward types as ‘ICU’ (including pediatric and adult ICU units), ‘not ICU’ (including ward types other than ICUs), and ‘unknown’ (data on the type of ward was unavailable). In total, Acinetobacter species BSIs documented between 2020 and 2021 rose by 57% compared to the period between 2018 and 2019. The increase was largely due to BSIs by Acinetobacter species resistant to carbapenem, with case counts rising by 114% and the percentage of resistance to carbapenem rising from 48% between 2018 and 2019 to 66% between 2020 and 2021.

The increase in BSIs caused by Acinetobacter species resistant to carbapenem was observed to be greater in ICU-admitted individuals (144%) than non-ICU-admitted individuals (41%). The slight increase in BSIs caused by Acinetobacter species susceptible to carbapenem BSIs during 2020 and 2021 in comparison to the period between 2018 and 2019 did not show statistical significance.

The increase (116%, n=5,472)) in Acinetobacter species BSI cases between 2020 and 2021 was most prominent among Group 3 nations, compared to 2,529 cases documented in the 2018 to 2019 period. Among Group 2 nations, a similar increase (109%) was observed. However, with lesser reported cases per nation, Group 1 nations documented only 52 cases between 2020 and 2021, with no significant difference in case counts documented between 2018 and 2019 (n=54).

Conclusions

Overall, the study findings showed an enormous increase in BSIs caused by Acinetobacter species resistant to carbapenem among EU/EEA nations during the initial two years of the COVID-19 pandemic, a challenging period for health authorities across the globe. The findings showed that controlling the further spread of Acinetobacter was most challenging for Group 3 nations where carbapenem-resistant Acinetobacter species were prevalent in the pre-pandemic period.

The patterns of Acinetobacter species BSI observed among EU/EEA nations have raised global concerns since carbapenem resistance has caused a considerable disease burden among vulnerable and hospitalized individuals. Therefore, continued surveillance efforts are required to monitor alterations in carbapenem resistance and Acinetobacter BSI development.