The Impact of Multidrug-Resistant Acinetobacter baumannii Infection in Critically Ill Patients with or without COVID-19 Infection

Impact of COVID-19 on epidemiology and mortality risk factors in patients with carbapenem-resistant Acinetobacter baumannii bloodstream infections in a tertiary care hospital in Thailand

OBJECTIVE

To investigate the epidemiology of Acinetobacter baumannii isolates and bloodstream infections (BSIs) during the COVID-19 pandemic.

METHODS

A. baumannii isolated from clinical specimens were identified between 2019 and 2023. The quarterly incidence of carbapenem-resistant A. baumannii (CRAB) was described. Hospital-wide carbapenem consumption was quantified as defined daily doses (DDD). Risk factors for CRAB acquisition and 30-day all-cause mortality in CRAB BSIs were determined.

RESULTS

A total of 400 new CRAB cases were identified. The incidence of total CRAB clinical isolates fluctuated (P = 0.68), while the incidence of CRAB BSIs increased (P = 0.04). No correlation was found between CRAB incidence and hospital-wide carbapenem consumption (P = 0.93). There were 75 CRAB BSI cases and 47 non-carbapenem-resistant A. baumannii (NCRAB) BSI cases. Prior antibiotic exposure (aOR 8.67; P < 0.001) and presence of multidrug-resistant organisms (MDROs) within 90 days (aOR 4.63; P = 0.02) were significantly associated with CRAB BSI acquisition. CRAB BSIs had higher 30-day mortality (66.67%) than NCRAB BSIs (25.53%) (aHR 0.83, 95% CI 0.26-2.59; P=0.74). Pitt bacteremia score (aHR 1.20; P = 0.01) and recent COVID-19 infection (aHR 2.86; P = 0.03) were independent predictors of mortality in CRAB BSIs.

CONCLUSIONS

The incidence of total CRAB clinical isolates fluctuated, while the incidence of CRAB BSIs significantly increased. Previous antimicrobial exposure and presence of MDROs within 90 days were risk factors for CRAB. Pitt bacteremia score and recent COVID-19 infection were linked to higher CRAB BSI mortality.

Phenotypical and Molecular Characterization of Acinetobacter baumannii Isolated from Hospitalized Patients During the COVID-19 Pandemic in Brazil

The goal of the present study was to analyze Acinetobacter baumannii strains isolated from hospitalized patients in the period of the COVID-19 pandemic by phenotypic and molecular methods and evaluate their antimicrobial resistance patterns and biofilm production. Forty-seven strains were isolated in 2021-2022 from a hospital in Brazil, and were identified by VITEK®2, MALDI-TOF/MS (VITEK MS® and MALDI Biotyper®), and 16S rRNA sequencing. Fourier-transform infrared (FTIR) spectroscopy was applied for typing and antimicrobial susceptibility testing (AST). In addition, biofilm formation and disinfectant tolerance tests were used. All methods accurately identified all the A. baumannii strains. FTIR typing identified 23 different profiles and 11 clusters, as well as differentiated between the strains from patients with and without COVID-19. Most strains exhibited resistance to the drugs tested, 91.5% of the strains were classified as XDR, 6.4% of the strains were MDR and only 1 strain was classified as non-MDR. Over half of the strains (n = 27, 57.4%) produced biofilms on polystyrene. Sodium hypochlorite (1.0%/15 min) was the best option for effective disinfection. Overall, this study will lay the foundation for further research on effective cleaning protocols for the eradication of A. baumannii biofilms, as well as the use of FTIR for pathogen surveillance in healthcare settings.

Iron-dependent mechanisms in Acinetobacter baumannii: pathogenicity and resistance

Acinetobacter baumannii is a Gram-negative opportunistic pathogen that poses a significant challenge in healthcare settings, particularly in ICUs, due to its MDR and high mortality rates, especially among critically ill coronavirus disease 2019 patients. Iron is crucial for the survival, growth and pathogenicity of A. baumannii, and the bacterium has developed multiple iron acquisition systems, including siderophore production, haem uptake and TonB-dependent transport mechanisms, to adapt to the iron-limited environment within the host. Although specific studies on A. baumannii are limited, mechanisms from other bacterial species suggest that similar iron acquisition strategies may play a key role in its virulence. Therapeutic approaches targeting these iron-dependent systems, such as the siderophore-conjugated cephalosporin cefiderocol, have shown potential in overcoming MDR A. baumannii infections. Additionally, strategies such as synthetic siderophores, TonB receptor inhibitors and iron chelators are under investigation to enhance treatment outcomes. Future research should prioritize validating these mechanisms in A. baumannii, advancing clinical trials for these therapies and exploring combination treatments to mitigate resistance and improve clinical outcomes in severely affected patients.

Unveiling the impact: COVID-19's influence on bacterial resistance in the Kingdom of Bahrain

BACKGROUND

Antibiotic resistance is a growing global health threat, and understanding local trends in bacterial isolates and their susceptibility patterns is crucial for effective infection control and antimicrobial stewardship. The coronavirus disease 2019 (COVID-19) pandemic has introduced additional complexities, potentially influencing these patterns.

AIM

To analyze trends in bacterial isolates and their antibiotic susceptibility patterns at Salmaniya Medical Complex from 2018 to 2023, with a specific focus on the impact of the COVID-19 pandemic on these trends.

METHODS

A retrospective analysis of microbiological data was conducted, covering the period from 2018 to 2023. The study included key bacterial pathogens such as Escherichia coli (E. coli), Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus, among others. The antibiotic susceptibility profiles of these isolates were assessed using standard laboratory methods. To contextualize the findings, the findings were compared with similar studies from other regions, including China, India, Romania, Saudi Arabia, the United Arab Emirates, Malaysia, and United States.

RESULTS

The study revealed fluctuating trends in the prevalence of bacterial isolates, with notable changes during the COVID-19 pandemic. For example, a significant increase in the prevalence of Staphylococcus aureus was observed during the pandemic years, while the prevalence of E. coli showed a more variable pattern. Antibiotic resistance rates varied among the different pathogens, with a concerning rise in resistance to commonly used antibiotics, particularly among Klebsiella pneumoniae and E. coli. Additionally, the study identified an alarming increase in the prevalence of multidrug-resistant (MDR) strains, especially within Klebsiella pneumoniae and E. coli isolates. The impact of the COVID-19 pandemic on these trends was evident, with shifts in the frequency, resistance patterns, and the emergence of MDR bacteria among several key pathogens.

CONCLUSION

This study highlights the dynamic nature of bacterial isolates and their antibiotic susceptibility patterns at Salmaniya Medical Complex, particularly in the context of the COVID-19 pandemic. The findings underscore the need for continuous monitoring and effective anti-microbial stewardship programs to combat the evolving threat of antibiotic resistance. Further research and policy initiatives are required to address the identified challenges and improve patient outcomes in the face of these ongoing challenges.

Colistin Treatment Outcomes in Gram-Negative Bacterial Infections in the Northeast of Romania: A Decade of Change Through Pandemic Challenges

Background: The rise in multidrug-resistant (MDR) Gram-negative bacteria (GNB) poses a critical threat to global health, exacerbated by the increased use of antibiotics during the SARS-CoV-2 pandemic. Colistin, often considered a last-resort antibiotic, has seen heightened usage, raising concerns about resistance and clinical outcomes. This study investigates the evolution of colistin resistance in GNB during the SARS-CoV-2 pandemic, with a focus on clinical outcomes in colistin-treated patients. Methods: Conducted in "Saint Spiridon" Hospital, Iasi, Romania, the study assesses antibiotic usage, trend in GNB resistance to colistin, and mortality rates across distinct pandemic phases (pre-pandemic, Delta, Omicron, and post-pandemic). A retrospective longitudinal analysis spanning 2011 to 2023 was performed. Statistical models were employed to analyze mortality risk and assess the pandemic's impact on antimicrobial dynamics. Results: Colistin usage increased significantly during the pandemic, with the highest doses recorded during the Omicron phase. Resistance to colistin, particularly among A. baumannii and K. pneumoniae, was associated with increased mortality rates. The statistical model demonstrated robust predictive accuracy for mortality across the pandemic phases, with an AUC of 0.866 in the post-pandemic period. The findings underscore the critical role of A. baumannii as a driver of adverse outcomes, with co-infections significantly linked to systemic infections and higher mortality. Conclusions: The study highlights the evolving trends in colistin therapy and resistance, emphasizing the pandemic's impact on antimicrobial stewardship and the persistent challenges posed by MDR pathogens. We emphasize the need for antimicrobial resistance surveillance, including the monitoring of colistin resistance, which is considered a last-resort antibiotic.

Risk factors for bloodstream infection in COVID-19 patients in intensive care units: a systematic review and meta-analysis

BACKGROUND

Risk factors for bloodstream infection in patients with COVID-19 in the intensive care unit (ICU) remain unclear. The purpose of this systematic review was to study the risk factors for BSI in patients admitted to ICUs for COVID-19.

METHODS

A systematic search was performed on PubMed, EMBASE, Cochrane Library, and Web of Science up to July 2024. Data were reported as combined odds ratio (OR) for categorical variables and weighted mean difference (WMD) for continuous variables.

RESULTS

6914 studies were retrieved, of which 55 were included in the meta-analysis. Men (OR = 1.28, 95% CI: 1.10-1.50, P = 0.006), high SAPS II score (WMD = 6.43, 95% CI: 0.23-12.63, P = 0.042), diabetes (OR = 1.34, 95% CI: 1.04-1.73, P = 0.022), tracheal intubation (OR = 8.68, 95% CI: 4.68-16.08, P < 0.001), mechanical ventilation (OR = 22.00, 95% CI: 3.77-128.328, P < 0.001), ECMO (OR = 2.70, 95% CI: 1.17-6.26, P = 0.020), central venous cannulation (OR = 9.33, 95% CI: 3.06-28.43, P < 0.001), prolonged ICU stay (WMD = 10.37, 95% CI: 9.29-11.44, P < 0.001), methylprednisolone use (OR = 2.24, 95% CI: 1.24-4.04, P = 0.008), and the combination of methylprednisolone and Tocilizumab (OR = 4.54, 95% CI: 1.09-18.88, P = 0.037) were risk factors for ICU-BSI in COVID-19 patients.

CONCLUSION

We identified 10 risk factors for ICU-BSI in COVID-19 patients. In future studies, these factors can be combined to establish a more comprehensive and accurate prediction model for ICU-BSI in COVID-19 patients. Targeted measures can be taken earlier to control BSI.

Bloodstream Infection in the Intensive Care Unit: Evolving Epidemiology and Microbiology

Bloodstream infections (BSIs) arising in the intensive care unit (ICUs) present a significant challenge and we completed a narrative review of the emerging literature on this issue. Multiple reports document that these infections are associated with substantial morbidity and mortality. Also, they can be caused by a variety of pathogens. Generally classified as either community or hospital in onset, or as either primary or secondary in origin, the microbiology of ICU BSIs varies across the globe. Gram-positive pathogens predominate in certain regions such as the United States while Gram-negative organisms occur more frequently in Europe, Asia, and Latin America. The incidence of ICU BSIs climbed during the recent pandemic. BSIs complicating the care of persons suffering from Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection significantly heighten the risk for death compared to patients who develop ICU BSIs but who are not infected with SARS-CoV-2. Furthermore, rates of antimicrobial resistance are generally increasing in ICU BSIs. This fact complicates attempts to ensure that the patient receives initially appropriate antimicrobial therapy and is of particular concern in Methicillin-resistant Staphylococcus aureus, Carbapenem-resistant Enterobacterales, and Acinetobacter baumannii. Fortunately, with respect to clinical application, preventive measures exist, and recent analyses suggest that increased collaboration between infectious disease specialists and intensivists can improve patient outcomes.

Clinical impact of COVID-19 in patients with carbapenem-resistant Acinetobacter baumannii bacteraemia

The aim of this study was to evaluate the impact of coronavirus disease 2019 (COVID-19) on treatment outcomes in critically ill patients with carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infection (BSI). This single-centre, retrospective cohort study was conducted in a 1,048-bed university-affiliated tertiary hospital in the Republic of Korea from January 2021 to March 2022. The study participants included consecutive hospitalised adult patients (aged ≥18 years) in the intensive care unit with CRAB monomicrobial BSI. During the study period, a total of 70 patients were included in our study, and 24 (34.3%) were diagnosed with COVID-19. The 28-day mortality rate was 64.3%. In the multivariate Cox proportional hazard regression analysis, diagnosis of COVID-19 (hazard ratio (HR), 2.91; 95% confidence interval (CI): 1.45-5.87), neutropenia (HR, 2.76; 95% CI: 1.04-7.29), Pitt bacteraemia score (per point; HR, 1.30; 95% CI: 1.19-1.41), and appropriate definite antibiotic therapy (HR, 0.31; 95% CI: 0.15-0.62) were independent predictors of 28-day mortality in patients with CRAB BSI. In conclusion, our findings suggested that COVID-19 has a negative prognostic impact on patients with CRAB BSI. Further study is needed to investigate the specific mechanisms of how COVID-19 worsens the prognosis of CRAB infection.

Acinetobacter baumannii Bloodstream Infections in the COVID-19 Era: A Comparative Analysis between COVID-19 and Non-COVID-19 Critically Ill Patients

The coronavirus disease (COVID-19) pandemic increased the incidence of severe infections caused by multidrug-resistant (MDR) pathogens among critically ill patients, such as Acinetobacter baumannii (AB), whose bloodstream infections (BSIs) have been associated with significant mortality. Whether there is any difference in outcome between COVID-19 and non-COVID-19 patients with AB BSI still remains unknown. We conducted a retrospective study comparing clinical characteristics and outcomes of COVID-19 versus non-COVID-19 critically ill patients with AB BSI. Overall, 133 patients with AB BSI (102 COVID-19, 31 non-COVID-19) were studied. The 28-day mortality rate was high and did not differ significantly (69.6% COVID-19 vs. 61.3% non-COVID-19, p = 0.275). Patients with septic shock had a higher mortality rate irrespective of their status with the majority of deaths occurring during the first 7 days. COVID-19 patients were more likely to have ventilator-associated pneumonia (VAP) as the source of BSI (55.8% vs. 22.3%, respectively, p = 0.0001) and were more likely to develop acute respiratory distress syndrome (ARDS) (78.4% vs. 48.4%, respectively, p = 0.001), sepsis (86.3% vs. 67.7%, respectively, p = 0.03), and septic shock (88.3% vs. 58.1%, respectively, p = 0.007) compared to the non-COVID-19 patient group. In conclusion, COVID-19 patients with A. baumannii BSI have a high rate of mortality and more often develop septic shock, while VAP is the main origin of their BSI.

Phenotypic and Molecular Characteristics of Carbapenem-Resistant Acinetobacter baumannii Isolates from Bulgarian Intensive Care Unit Patients

Carbapenem-resistant Acinetobacter baumannii (CRAB) is designated as an urgent public health threat, both due to its remarkable multidrug resistance and propensity for clonal spread. This study aimed to explore the phenotypic and molecular characteristics of antimicrobial resistance in CRAB isolates (n = 73) from intensive care unit (ICU) patients in two university hospitals in Bulgaria (2018–2019). The methodology included antimicrobial susceptibility testing, PCR, whole-genome sequencing (WGS), and phylogenomic analysis. The resistance rates were as follows: imipenem, 100%; meropenem, 100%; amikacin, 98.6%; gentamicin, 89%; tobramycin, 86.3%; levofloxacin, 100%; trimethoprim–sulfamethoxazole, 75.3%; tigecycline, 86.3%; colistin, 0%; and ampicillin–sulbactam, 13.7%. All isolates harbored blaOXA-51-like genes. The frequencies of distribution of other antimicrobial resistance genes (ARGs) were: blaOXA-23-like, 98.6%; blaOXA-24/40-like, 2.7%; armA, 86.3%; and sul1, 75.3%. The WGS of selected extensively drug-resistant A. baumannii (XDR-AB) isolates (n = 3) revealed the presence of OXA-23 and OXA-66 carbapenem-hydrolyzing class D β-lactamases in all isolates, and OXA-72 carbapenemase in one of them. Various insertion sequencies, such as ISAba24, ISAba31, ISAba125, ISVsa3, IS17, and IS6100, were also detected, providing increased ability for horizontal transfer of ARGs. The isolates belonged to the widespread high-risk sequence types ST2 (n = 2) and ST636 (n = 1) (Pasteur scheme). Our results show the presence of XDR-AB isolates, carrying a variety of ARGs, in Bulgarian ICU settings, which highlights the crucial need for nationwide surveillance, especially in the conditions of extensive antibiotic usage during COVID-19.