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Copyright of Klinická Mikrobiologie a Infekční Lékařství is the property of TRIOS, spol. sr.o. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Anaesthesiology & Intensive Medicine / Anesteziologie a Intenzivní Medicína is the property of Czech Medical Association of JE Purkyne and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: The period of the COVID-19 pandemic had a significant impact on the healthcare system, including its effect on compliance with the established procedures of a rational antibiotic policy, especially in the context of nosocomial pneumonia, where it was very difficult to distinguish a possible bacterial superinfection from a severe inflammatory reaction caused by the SARS-CoV-2 virus. The aim of the present study was to analyze the antimicrobial resistance of bacterial pathogens isolated from the lower respiratory tract and their clonality in intensive care patients in 2022 and to compare it with the previous COVID-19 period., Material and Methods: Bacterial strains isolated from the lower respiratory tract (LRT) of patients hospitalized at the Department of Anaesthesiology, Resuscitation and Intensive Care, Olomouc University Hospital (DARIC) over a three-year period (January 1, 2020 - December 31, 2022) were included in the study. The susceptibility to antibiotics was determined by the standard microdilution method according to the EUCAST criteria, and selected isolates were compared using pulsed-field gel electrophoresis (PFGE)., Results: The resistance of the most common bacterial pathogens isolated from the LRT of patients hospitalized at DARIC did not change significantly during the COVID-19 (2020-2021) and post-COVID-19 (2022) periods, with the exception of Serratia marcescens and Enterococcus faecium species. These two showed an increase in the number of strains during the COVID-19 pandemic, as well as a significant increase in the proportion of resistant strains. In the case of Serratia marcescens, there was a subsequent decrease in the number of isolates and their resistance in 2022. For Enterococcus faecium, the total number of isolates also decreased significantly, but the frequency of vancomycin-resistant isolates (VRE) continued to increase. During the COVID-19 pandemic, increased VRE detection can be linked to proven clonal spread, but significant clonality was no longer confirmed in 2022. Comparison of similarity by PFGE in other bacterial species also did not reveal significant horizontal transmission between patients in the post-COVID-19 period, as most isolates (85%) showed a unique restriction profile., Conclusions: The results indicate that the frequency and antimicrobial resistance of the majority of the most common bacterial pathogens from the LRT of patients hospitalized at DARIC in the post-pandemic period remain comparable to the time before and during the COVID-19 pandemic outbreak. An exception is Enterococcus faecium, which showed an increase in vancomycin resistance in both the COVID-19 and the post-COVID-19 periods.

Objectives: The COVID-19 pandemic has had a major impact on the healthcare system, which has been forced to manage large numbers of patients, including those with respiratory insufficiency and in need of oxygen therapy. Due to concerns about bacterial co-infection, antibiotic therapy was administered to many patients. The aim of the present study was to compare antimicrobial resistance in intensive care patients in the pre-pandemic and pandemic periods., Material and Methods: Patients hospitalized at the Department of Anesthesiology, Resuscitation and Intensive Care Medicine of the University Hospital Olomouc in the pre-COVID-19 period (2018-2019) and during the pandemic (2020-2021) were enrolled in the study. Clinical samples from the lower respiratory tract were routinely collected twice a week, with one strain of a given species first isolated from each patient being included in the study., Results: While several bacterial species (Escherichia coli, Proteus mirabilis and Haemophilus influenzae) were found to occur less frequently, an increased occurrence was documented for Enterococcus faecium, Serratia marcescens and Klebsiella variicola. Overall, however, it can be concluded that there was no major change in the frequency of bacterial pathogens isolated from the lower respiratory tract during the COVID-19 period. Similarly, with only a few exceptions, antimicrobial resistance did not change significantly. More significant increases in resistance to piperacillin/tazobactam, cefotaxime, ciprofloxacin and gentamicin have been demonstrated for Serratia marcescens. However, a decrease in the resistance of Pseudomonas aeruginosa and Burkholderia cepacia complex to meropenem was also observed., Conclusions: There was no significant change in the frequency of bacterial pathogens and their resistance to antibiotics during the COVID-19 pandemic. However, there was an increase or decrease in the percentage of some species and in their resistance.

Aim: The study aimed to characterize enterococcal infections at the University Hospital Olomouc and to define antibiotic treatment options., Material and Methods: The data was obtained from the ENVIS LIMS laboratory information system. Between 1 January 2015 and 31 December 2019, clinically relevant enterococci in the hospital and their resistance to antibiotics were retrospectively evaluated. Until mid-2016, criteria defined by Facklam and Collins and biochemical properties determined with the Encoccus test were used for identification. Subsequently, all enterococci were identified using the MALDI-TOF MS system. The susceptibility to antibiotics was determined using a standard microdilution method according to the EUCAST criteria., Results: A total of 8 239 clinically relevant enterococci were isolated over the 5-year period. The most frequently isolated species were Enterococcus faecalis and Enterococcus faecium, which accounted for more than 90% in the period 2017-2019. Enterococci were most frequently isolated from urine (35 %), surgical wounds (17 %) and urethral/vaginal swabs (17 %). Clinically relevant enterococci were most commonly isolated from patients with oncological diagnoses (22%), those with urinary and genital diseases (15%) and respiratory diseases (9%). Enterococcus faecalis strains showed very low resistance to the antibiotics tested. Enterococcus faecium was shown to have 24 % proportion of vancomycin-resistant strains (VRE)., Conclusion: Primary antibiotics suitable for treating infections with the etiological role of Enterococcus faecalis include aminopenicillins, in case of severe infections in combination with aminoglycosides, in particular gentamicin. For Enterococcus faecium strains, glycopeptides must be chosen. To treat VRE, linezolid or tigecycline are indicated.

Background: Important hospital-acquired infections include pneumonia, mainly because of the increasing resistance of bacterial pathogens to antimicrobials and the associated potential failure of antibiotic therapy. The present study aimed at determining the most frequent etiological agents of hospital-acquired pneumonia (HAP) and assessing the relationship between 30-day mortality and adequacy of antibiotic therapy. Based on the obtained information, optimal patterns of antibiotic therapy were to be defined, including a pharmacoeconomic perspective., Methods: In patients with clinically confirmed HAP, bacterial etiological agents were identified, their susceptibility to antimicrobials was determined and statistical methods were used to assess the relationship between adequacy of antibiotic therapy and 30-day mortality., Results: The study comprised 68 patients with clinically confirmed HAP. The most common etiological agents were strains of Pseudomonas aeruginosa (30.8 %), Klebsiella pneumoniae (23.1 %) and Burkholderia cepacia complex (15.4 %). Gram-negative bacteria accounted for 86.5 % of all bacterial pathogens. The overall mortality reached 42.5 %. In the subgroup of patients with inadequate antibiotic therapy, 30-day mortality was significantly higher (83.3 %) than in the subgroup with adequate therapy (30.0 %; p = 0.002). The risk for 30-day mortality was 2.78 times higher in case of inadequate antibiotic therapy (95%CI: 1.52-5.07). The proportion of Pseudomonas aeruginosa strains was significantly higher in the subgroup of patients with inadequate antibiotic therapy than in those with adequate therapy (67 % vs. 27 %; p = 0.032)., Conclusion: Results of the present study suggest a significant relationship between mortality of patients with HAP and ineffective antibiotic therapy due to resistance of the bacterial pathogen. Thus, it is clear that initial antibiotic therapy must be based on qualified assumption of sufficient activity against the most common bacterial pathogens and results of surveillance of bacterial resistance in the relevant epidemiological unit. At the same time, however, it must be stressed that it is impossible to cover all potential variants of the etiological agents and their resistance phenotypes.

Introduction: The objectives were to assess the prevalence of etiologic agents of hospital-acquired pneumonia (HAP) in patients staying in four big hospitals in the Czech Republic and requiring artificial ventilation. The resistance of the isolated pathogens to antibiotics was determined and initial antibiotic therapy was discussed., Methods: Included in the study were 155 patients with HAP staying from May 1, 2013 to January 31, 2014 in the Departments of Anesthesiology and Critical Care in the following four centers: Thomayer Hospital Prague, University Hospital Brno, University Hospital Hradec Králové and University Hospital Olomouc. From these patients, endotracheal secretion samples were processed using standard microbiology methods. In identified bacterial strains, susceptibility to antibiotics was tested with the microdilution method according to the EUCAST recommendations. Production of ESBL and AmpC beta-lactamases was detected by disk diffusion tests specific for the particular enzymes. ESBL- and AmpC-positive isolates were subjected to basic genetic analysis., Results: Over the study period, a total of 266 isolates were obtained from 140 patients, with 15 patients having negative culture result. Late-onset pneumonia was present in 72 %. Gram-negative bacteria were most prevalent (81 %), namely Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli. Phenotypic tests for production of broad spectrum beta-lactamases were positive in 37 % of Enterobacteriaceae. Genes for CTX-M, SHV, TEM beta-lactamases or CIT and DHA types of AmpC enzymes were detected. No carbapenemase-producing bacteria, methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci were detected., Conclusion: The study showed that HAP in the Czech Republic was mostly of Gram-negative etiology. Variable antibiotic susceptibility in the two most frequent etiological agents (Pseudomonas aeruginosa and Klebsiella pneumoniae) resulted in severe therapeutic difficulties. A total of 49 % of patients received inadequate therapy. This fact suggests the impact of antibiotic resistance on intensive care patients´ survival or death. Our study confirmed that one in three patients dies because of HAP.

Objective: Recently, there has been a renaissance of the use of the antibiotic colistin resulting from increasing resistance of bacterial pathogens, particularly in intensive care patients. The study aimed at assessing the impact of colistin consumption on the prevalence of colistin-resistant bacteria in the University Hospital Olomouc (UHO)., Methods: A laboratory database was retrospectively searched to identify all clinically significant colistin-resistant bacterial strains isolated between 2007 and 2011. These data were compared with colistin consumption over the same period and the results were statistically processed., Results: Over the study period, a total of 6 338 clinically significant colistin-resistant strains were detected in the UHO (Acinetobacter spp., Burkholderia cepacia complex, Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella spp., Morganella morganii, Proteus spp., Providencia spp., Pseudomonas spp., Serratia marcesces and Stenotrophomonas maltophilia). Over the same period, the consumption of colistin increased nearly 10-fold. With the increasing colistin consumption, the numbers of colistin-resistant strains of Pseudomonas aeruginosa and Acinetobacter spp. decreased over that period of time. By contrast, there was an increase in the rates of naturally Burkholderia cepacia complex strains naturally resistant to colistin. An alarming finding is that the prevalence of colistin-resistant strains of Klebsiella pneumoniae increased in the last years of the study period, especially in intensive care patients., Conclusions: In the UHO, higher consumption of colistin was accompanied by increased numbers of colistin-resistant strains. There was a marked increase of Burkholderia cepacia complex strains and, recently, a statistically insignificant but alarming increase in colistin-resistant Klebsiella pneumoniae strains.

As a result of high resistance of bacterial pathogens to broad-spectrum penicillins and cephalosporins, carbapenems have been increa-singly used recently. The presented study aimed at analyzing the association between carbapenem consumption and resistance of selected Gramnegative pathogens to meropenem. Using linear regression analysis, a statistically significant association was found between carbapenem consumption and resistance of Pseudomonas aeruginosa.

Objective: The study aimed at determining the presence of qnr genes in ESBL-positive strains of Klebsiella pneumoniae isolated from clinical material obtained from patients hospitalized in several intensive care units in the University Hospital Olomouc., Material and Methods: The study comprised 100 ESBL-producing Klebsiella pneumoniae isolates from clinical samples obtained from patients hospitalized between 1 January 2008 and 31 January 2011. blaTEM, blaSHV, blaCTX-M and qnr genes were detected by polymerase chain reaction (PCR). To compare the similarity or identity of the isolates, pulsed-field gel electrophoresis (PFGE) of DNA fragments was used., Results and Conclusion: The blaSHV gene was detected in 99 from 100 isolates of Klebsiella pneumoniae, which is in accordance with the published data that suppose the chromosomal position of the blaSHV-1 gene in this species. The blaCTX-M gene was detected in 77 isolates. The qnr genes were revealed in 56 isolates and majority (76.8 %) of these qnr-positive bacteria carried also the genes encoding the beta-lactamases CTX-M and TEM. In all cases, the qnrB variant was detected. Plasmids from nine different incompatibility groups were identified, in most cases from the IncFII group (52 isolates). Antibiotic susceptibility tests revealed high frequency of resistance not only to beta-lactams, but also to aminoglycosides, tetracycline and sulfamethoxazole/trimethoprim. PFGE detected 65 different strains and several groups of isolates with the same restriction profile. Although the clinical significance of the qnr genes is not well established, their presence in ESBL-positive Enterobacteriaceae is not negligible and it should be kept in mind.

Objectives: Carbapenems are the drugs of choice for the treatment of serious infections caused by ESBL- and AmpC-positive Enterobacteriaceae. An increasing trend of resistance to these antibiotics has been observed recently. The aim of the study was to determine resistance to carbapenems in clinical isolates of the Enterobacteriaceae family and its mechanism., Methods: Between 1 April 2009 and 31 August 2010, Enterobacteriaceae were isolated from clinical samples obtained from patients hospitalized in the University Hospital Olomouc, Czech Republic (1,406 beds incl. 155 ICU beds). The strains were identified using the standard microbiological methods and their susceptibility to antibiotics was determined by the microdilution method. The identification of the isolates with the minimum inhibitory concentration (MIC) of meropenem of 2 mg/L or more was confirmed by the Phoenix automated system (Becton Dickinson). The MIC of meropenem was verified by the E-test and also Phoenix automated system. The isolates were tested for carbapenemase production using the modified Hodge test, a combined test with 3-aminophenylboronic acid (3-APB) and EDTA, the CD-test for serine carbapenemases and modified DDST (mDDST) for metallo-beta-lactamases (MBL). ESBL and AmpC production was determined by the mDDST and modified AmpC test, respectively. Genes encoding production of serine carbapenemases, MBL, bla(OXA-23), bla(OXA-48), ESBL and AmpC enzymes were detected with a set of primers that amplify specific segments of individual beta-lactamases. TEM- and SHV-positive PCR products were characterized by restriction analysis., Results: From a total of 12,605 Enterobacteriaceae, 9 strains were isolates with the MIC of meropenem of 2 mg/L or more. Seven isolates were classified as Klebsiella pneumoniae and two as Enterobacter cloacae. The MIC of meropenem for these strains ranged from 2 mg/L to 16 mg/L. The modified Hodge test, the combined test with 3-APB and EDTA, CD-test, mDDST for MBL and a series of PCR analyses did not detect production of class A carbapenemases, MBL, OXA-23 or OXA-48 enzymes in any of the tested strains. In 6 Klebsiella pneumoniae strains and 1 Enterobacter cloacae strain, the mDDST test and genetic analysis revealed ESBL production (CTX-M and SHV types), and in 2 strains, AmpC production was detected (DHA and EBC types)., Conclusion: The prevalence of the Enterobacteriaceae with the MIC of meropenem ≥ 2 mg/L in the University Hospital Olomouc was 0.07 %. None of the strains produced either serine carbapenemases or MBL. Borderline resistance of the strains to carbapenems was determined by the ESBL and AmpC production with another associated mechanism of resistance.