Association between Pseudomonas aeruginosa virulence factors, carbapenem resistance mechanisms and clinical course of disease

[...]. The aim of the study: The aim of the study is to evaluate the change of carbapenem resistance level of P. aeruginosa strains and the impact of virulence factors and carbapenem resistance mechanisms on clinical course of infection. The objectives of the study: 1. To evaluate the change of antimicrobial resistance level of P. aeruginosa strains isolated from respiratory tract samples, during 2003, 2008, 2011 years. 2. To identify the risk factors for developing infectious process caused by carbapenem-resistant P. aeruginosa strains. 3. To determine the risk factors for carbapenem resistance mechanisms in P. aeruginosa strains. 4. To evaluate the correlation of virulence factors: carbapenem resistance, MBL production, biofilm production, serogroup prevalence, resistance to bactericidal serum activity of P. aeruginosa strains, isolated from different clinical samples and clinical course of infectious disease. [...]

Associations between <i>β</i>-Lactamase Types of <i>Acinetobacter baumannii</i> and Antimicrobial Resistance

Background and objective: Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen that not only possesses intrinsic resistance to many classes of antibiotics, but is also capable of rapidly developing antimicrobial resistance during treatment. The aim of this study was to determine the characteristics of resistance of A. baumannii strains to β-lactams and other tested antibiotics, to evaluate the associations between the phenotypes of resistance to β-lactams and other tested antibiotics, and to evaluate the changes in antibiotic resistance of A. baumannii strains over 5 years by comparing the periods of 2016–2017 and 2020–2021. Materials and methods: A total of 233 A. baumannii strains were isolated from different clinical specimens of patients treated at the Hospital of Lithuanian University of Health Sciences in 2016–2017 (n = 130) and 2021–2022 (n = 103). All clinical cultures positive for A. baumannii were analyzed. The type of β-lactamase was detected by phenotypic methods using ESBL plus AmpC screen disk tests and the combination meropenem disk test. Results: In both periods, all A. baumannii strains were resistant to ciprofloxacin; resistance to carbapenems, piperacillin/tazobactam, gentamicin, and tobramycin was noted in more than 80% of strains. A comparison of two periods showed that the percentages of A. baumannii strains producing two or three types of β-lactamases were significantly greater in 2021–2022 than in 2016–2017 (94.2% and 5.8% vs. 17.7% and 2.3%, respectively, p β-lactamases were more often resistant to tigecycline, tetracycline, and doxycycline than strains producing one type of β-lactamase (p Conclusions: The frequency of isolation of A. baumannii strains producing two different types of β-lactamases (AmpC plus KPC, AmpC plus ESBL, or ESBL plus KPC) or three types of β-lactamases (AmpC, KPC, and ESBL) and the resistance rates to ampicillin/sulbactam, tigecycline, tetracycline, and doxycycline were significantly greater in 2020–2021 as compared with 2016–2017. The production of two or three types of β-lactamases by A. baumannii strains was associated with higher resistance rates to tetracyclines

Pseudomonas aeruginosa bacteremia: Associations with a source of infection and antibiotic resistance

Aim of the study. To determine the associations between the source of infection and antibiotic resistance in patients with Pseudomonas aeruginosa bacteremia. Material and methods. A retrospective analysis of 50 patients with Pseudomonas aeruginosa bacteremia was carried out. If sepsis was suspected, blood culture was incubated in an automatic system BACTEC 9240. Then bacteria were identified, and their antibiotic resistance was estimated by disc diffusion method. If Pseudomonas aeruginosa strains were resistant to three or more antibiotics, they were considered as multidrug-resistant.Results. The origin of bacteremia was confirmed in 33 (66%) patients. Lower respiratory tract was the predominant source of Pseudomonas aeruginosa bacteremia (81.8%, n=27) as compared with infection of wound (39.4%, n=13), urinary tract (15.2%, n=5), and drain or cerebrospinal fluid (9.1%, n=3) (P&lt;0.05). Eighteen percent (n=9) of strains, which caused bacteremia, were resistant to ceftazidime; 38% (n=19), to piperacillin; 22% (n=11), to imipenem; 26% (n=13), to meropenem; 24% (n=12), to ciprofloxacin; 40% (n=20), to gentamicin; and only 8% (n=4), to amikacin. Multidrug-resistant Pseudomonas aeruginosa strains were more frequently isolated if a source of infection was wound comparing to a source of other localization (61.5%, n=8 and 20.0%, n=4, respectively; P&lt;0.05). Resistance of Pseudomonas aeruginosa strains to imipenem was associated with resistance to ciprofloxacin (13.2%, n=5 and 50.0%, n=6, retrospectively; P&lt;0.05), but resistance to meropenem – both to ciprofloxacin and amikacin. Conclusions. The predominant source of Pseudomonas aeruginosa bacteremia was lower respiratory tract, and multidrug-resistant strains caused bacteremia more frequently if a source infection was wound. Pseudomonas aeruginosa resistance to carbapenems was associated with resistance to ciprofloxacin and resistance to meropenem – also to amikacin. Resistance of strains to ceftazidime and piperacillin was associated with resistance to gentamicin

Candidemia in an intensive care unit

Candidemia is becoming more actual because of better survival of even critically ill patients, wide use of antimicrobials, and increased numbers of invasive procedures and manipulations. Diagnosis of candidemia remains complicated, and costs of treatment and mortality rates are increasing. Objective. To evaluate the pathogens of candidemia, risk factors and their influence on outcome. Material and methods. Data of 41 patients with positive blood culture for Candida spp., who were treated in the intensive care units at the Hospital of Kaunas University of Medicine, were analyzed retrospectively. Results. Candidemia was caused by Candida albicans (C. albicans) in 48.8% (n=20) of patients and by non-albicans Candida in 51.2% (n=21) of patients. The main cause of candidemia was C. albicans in 2004 (83.3%, n=5), but in 2005 (63.6%, n=7), in 2006 (57.1%, n=4), and in 2007 (52.9%, n=9), the main cause was non-albicans Candida spp. The number of candidemia cases caused by C. albicans was decreased in 2005, 2006, and 2007 as compared with 2004, and the number of candidemia caused by non-albicans Candida spp. was decreased, respectively (P<0.05). More than 65% (n=34) of patients had severe disease (P<0.05). Lethal outcome was recorded in 58.5% of patients with candidemia. Mechanical ventilation was used in 76.9% (n=20) and urinary bladder catheter in 72.1% (n=19) of non-survivors and in 23.1% (n=6) and 26.9% (n=7) of survivors, respectively (P<0.05). Conclusions. There is an increase in the prevalence of candidemia in the intensive care units during the 4-year period; half of candidemia cases were caused by non-albicans Candida spp., and patients with candidemia caused by non-albicans Candida spp. are at higher risk of mortality.[...]

Changes in Antibiotic Resistance Level of Nosocomial Pseudomonas Aeruginosa Isolates in the Largest University Hospital of Lithuania

The aim was to estimate changes in the resistance rates of Pseudomonas aeruginosa (P. aeruginosa) strains isolated from patients treated in intensive care units of the largest university hospital. Materials and Methods. Isolates were identified with the Phoenix ID system (Becton Dickinson, USA). The minimum inhibitory concentration (MIC) of ceftazidime, ciprofloxacin, and amikacin were determined by the E-test and evaluated following the recommendations of the Clinical Laboratory Standards Institute. Results. In 2003, the proportion of P. aeruginosa strains resistant to piperacillin was greatest followed by strains resistant gentamicin and ciprofloxacin. In 2008, the resistance rates markedly changed being the highest to ciprofloxacin. An increase in the resistance rates to ciprofloxacin (+24%, P&lt;0.001) and ceftazidime (+8.3%, P&lt;0.05) was documented. In 2003, there were 66.7% of P. aeruginosa strains sensitive to all antibiotics tested, and this percentage decreased to 47.5% in 2008 (P&lt;0.05). During the study, a significant increase in the median MICs for ciprofloxacin and amikacin was observed (P&lt;0.001); however, no significant change was documented for ceftazidime. Conclusions. P. aeruginosa remains an important nosocomial pathogen with relatively high overall resistance to antimicrobial agents, and the resistance level is increasing

Ventilator-Associated Pneumonia due to Drug-Resistant Acinetobacter baumannii: Risk Factors and Mortality Relation with Resistance Profiles, and Independent Predictors of In-Hospital Mortality

A. baumannii; Mortality; Ventilator-associated pneumonia (VAP)A. baumannii; Mortalitat; Pneumònia associada a la ventilació mecànicaA. baumannii; Mortalidad; Neumonía asociada a la ventilación mecánicaBackground and objectives: High mortality and healthcare costs area associated with ventilator-associated pneumonia (VAP) due to Acinetobacter baumannii (A. baumannii). The data concerning the link between multidrug-resistance of A. baumannii strains and outcomes remains controversial. Therefore, we aimed to identify the relation of risk factors for ventilator-associated pneumonia (VAP) and mortality with the drug resistance profiles of Acinetobacter baumannii (A. baumannii) and independent predictors of in-hospital mortality. Methods: A retrospective ongoing cohort study of 60 patients that were treated for VAP due to drug-resistant A. baumannii in medical-surgical intensive care units (ICU) over a two-year period was conducted. Results: The proportions of multidrug-resistant (MDR), extensively drug-resistant (XDR), and potentially pandrug-resistant (pPDR) A. baumannii were 13.3%, 68.3%, and 18.3%, respectively. The SAPS II scores on ICU admission were 42.6, 48.7, and 49 (p = 0.048); hospital length of stay (LOS) prior to ICU was 0, one, and two days (p = 0.036), prior to mechanical ventilation (MV)-0, 0, and three days (p = 0.013), and carbapenem use prior to VAP-50%, 29.3%, and 18.2% (p = 0.036), respectively. The overall in-hospital mortality rate was 63.3%. In MDR, XDR, and pPDR A. baumannii VAP groups, it was 62.5%, 61.3%, and 72.7% (p = 0.772), respectively. Binary logistic regression analysis showed that female gender (95% OR 5.26; CI: 1.21⁻22.83), SOFA score on ICU admission (95% OR 1.28; CI: 1.06⁻1.53), and RBC transfusion (95% OR 5.98; CI: 1.41⁻25.27) were all independent predictors of in-hospital mortality. Conclusions: The VAP risk factors: higher SAPS II score, increased hospital LOS prior to ICU, and MV were related to the higher resistance profile of A. baumannii. Carbapenem use was found to be associated with the risk of MDR A. baumannii VAP. Mortality due to drug-resistant A. baumannii VAP was high, but it was not associated with the A. baumannii resistance profile. Female gender, SOFA score, and RBC transfusion were found to be independent predictors of in-hospital mortality

Characteristics of Carbapenem-Resistant Pseudomonas aeruginosa Strains in Patients with Ventilator-Associated Pneumonia in Intensive Care Units

The aim of this study was to determine the characteristics of carbapenem-resistant Pseudomonas aeruginosa (P. aeruginosa) strains and 5-year changes in resistance in a tertiary university hospital. Material and Methods. The study included 90 and 101 randomly selected P. aeruginosa strains serotyped in 2003 and 2008, respectively. The standardized disk diffusion test and E-test were used to determine resistance to antibiotics. P. aeruginosa strains were considered to have high-level resistance if a minimum inhibitory concentration (MIC) for imipenem or meropenem was &gt;32 μg/mL. To identify serogroups, sera containing specific antibodies against O group antigens of P. aeruginosa were used. P. aeruginosa isolates resistant to imipenem or/and meropenem were screened for metallo-β-lactamase (MBL) production by using the MBL E-test. Results. Comparison of the changes in resistance of P. aeruginosa strains to carbapenems within the 5-year period revealed that the level of resistance to imipenem increased. In 2003, 53.3% of P. aeruginosa strains were found to be highly resistant to imipenem, while in 2008, this percentage increased to 87.8% (P=0.01). The prevalence of MBL-producing strains increased from 15.8% in 2003 to 61.9% in 2008 (P&lt;0.001). In 2003 and 2008, carbapenem-resistant P. aeruginosa strains were more often resistant to ciprofloxacin and gentamicin than carbapenem-sensitive strains. In 2008, carbapenem- resistant strains additionally were more often resistant to ceftazidime, cefepime, aztreonam, piperacillin, and amikacin than carbapenem-sensitive strains. MBL-producing P. aeruginosa strains belonged more often to the O:11 serogroup than MBL-non-producing strains (51.7% vs. 34.3%, P&lt;0.05). A greater percentage of non-MBL-producing strains had low MICs against ciprofloxacin and amikacin as compared with MBL-producing strains. Conclusions. The results of our study emphasize the need to restrict the spread of O:11 serogroup P. aeruginosa strains and usage of carbapenems to treat infections with P. aeruginosa in the intensive care units of our hospita

Ventilator-associated pneumonia due to drug-resistant Acinetobacter baumannii: risk factors and mortality relation with resistance profiles, and independent predictors of in-hospital mortality

Background and objectives: High mortality and healthcare costs area associated with ventilator-associated pneumonia (VAP) due to Acinetobacter baumannii (A. baumannii). The data concerning the link between multidrug-resistance of A. baumannii strains and outcomes remains controversial. Therefore, we aimed to identify the relation of risk factors for ventilator-associated pneumonia (VAP) and mortality with the drug resistance profiles of Acinetobacter baumannii (A. baumannii) and independent predictors of in-hospital mortality. Methods: A retrospective ongoing cohort study of 60 patients that were treated for VAP due to drug-resistant A. baumannii in medical-surgical intensive care units (ICU) over a two-year period was conducted. Results: The proportions of multidrug-resistant (MDR), extensively drug-resistant (XDR), and potentially pandrug-resistant (pPDR) A. baumannii were 13.3%, 68.3%, and 18.3%, respectively. The SAPS II scores on ICU admission were 42.6, 48.7, and 49 (p=0.048); hospital length of stay (LOS) prior to ICU was 0, one, and two days (p=0.036), prior to mechanical ventilation (MV)–0, 0, and three days (p=0.013), and carbapenem use prior to VAP—50%, 29.3%, and 18.2% (p=0.036), respectively. The overall in-hospital mortality rate was 63.3%. In MDR, XDR, and pPDR A. baumannii VAP groups, it was 62.5%, 61.3%, and 72.7% (p=0.772), respectively. Binary logistic regression analysis showed that female gender (95% OR 5.26; CI: 1.21–22.83), SOFA score on ICU admission (95% OR 1.28; CI: 1.06–1.53), and RBC transfusion (95% OR 5.98; CI: 1.41–25.27) were all independent predictors of in-hospital mortality. Conclusions: The VAP risk factors: higher SAPS II score, increased hospital LOS prior to ICU, and MV were related to the higher resistance profile of A. baumannii. Carbapenem use was found to be associated with the risk of MDR A. baumannii VAP. [...]

SARS-CoV-2 Seroprevalence in Healthcare Workers of Kaunas Hospitals during the First Wave of the COVID-19 Pandemic

Background and objective: Serologic testing is a useful additional method for the diagnosis of COVID-19. It is also used for population-based seroepidemiological studies. The objective of the study was to determine SARS-CoV-2 seroprevalence in healthcare workers of Kaunas hospitals and to compare two methods for specific SARS-CoV-2 antibody testing. Materials and Methods: A total of 432 healthcare workers in Kaunas hospitals were enrolled in this study. Each participant filled a questionnaire including questions about their demographics, contact with suspected or confirmed COVID-19, acute respiratory symptoms, and whether they contacted their general practitioner, could not come to work, or had to be hospitalized. Capillary blood was used to test for SARS-CoV-2 specific immunoglobulin G (IgG) and immunoglobulin M (IgM) a lateral flow immunoassay. Serum samples were used to test for specific IgG and IgA class immunoglobulins using semiquantitative enzyme-linked immunosorbent assay (ELISA) method. Results: 24.77% of study participants had direct contact with a suspected or confirmed case of COVID-19. A total of 64.81% of studied individuals had at least one symptom representing acute respiratory infection, compatible with COVID-19. Lateral flow immunoassay detected SARS-CoV-2 specific IgG class immunoglobulins in 1.16% of the tested group. Fever, cough, dyspnea, nausea, diarrhea, headache, conjunctivitis, muscle pain, and loss of smell and taste predominated in the anti-SARS-CoV-2 IgG-positive group. Using ELISA, specific IgG were detected in 1.32% of the tested samples. Diarrhea, loss of appetite, and loss of smell and taste sensations were the most predominant symptoms in anti-SARS-CoV-2 IgG-positive group. The positive percent agreement of the two testing methods was 50%, and negative percent agreement was 99.66%. Conclusions: 1.16% of tested healthcare workers of Kaunas hospitals were anti-SARS-CoV-2 IgG-positive. The negative percent agreement of the lateral flow immunoassay and ELISA exceeded 99%

SARS-CoV-2 Seroprevalence in Healthcare Workers of Kaunas Hospitals during the First Wave of the COVID-19 Pandemic

Background and objective: Serologic testing is a useful additional method for the diagnosis of COVID-19. It is also used for population-based seroepidemiological studies. The objective of the study was to determine SARS-CoV-2 seroprevalence in healthcare workers of Kaunas hospitals and to compare two methods for specific SARS-CoV-2 antibody testing. Materials and Methods: A total of 432 healthcare workers in Kaunas hospitals were enrolled in this study. Each participant filled a questionnaire including questions about their demographics, contact with suspected or confirmed COVID-19, acute respiratory symptoms, and whether they contacted their general practitioner, could not come to work, or had to be hospitalized. Capillary blood was used to test for SARS-CoV-2 specific immunoglobulin G (IgG) and immunoglobulin M (IgM) a lateral flow immunoassay. Serum samples were used to test for specific IgG and IgA class immunoglobulins using semiquantitative enzyme-linked immunosorbent assay (ELISA) method. Results: 24.77% of study participants had direct contact with a suspected or confirmed case of COVID-19. A total of 64.81% of studied individuals had at least one symptom representing acute respiratory infection, compatible with COVID-19. Lateral flow immunoassay detected SARS-CoV-2 specific IgG class immunoglobulins in 1.16% of the tested group. Fever, cough, dyspnea, nausea, diarrhea, headache, conjunctivitis, muscle pain, and loss of smell and taste predominated in the anti-SARS-CoV-2 IgG-positive group. Using ELISA, specific IgG were detected in 1.32% of the tested samples. Diarrhea, loss of appetite, and loss of smell and taste sensations were the most predominant symptoms in anti-SARS-CoV-2 IgG-positive group. The positive percent agreement of the two testing methods was 50%, and negative percent agreement was 99.66%. Conclusions: 1.16% of tested healthcare workers of Kaunas hospitals were anti-SARS-CoV-2 IgG-positive. The negative percent agreement of the lateral flow immunoassay and ELISA exceeded 99%