Bacterial Community- and Hospital-Acquired Pneumonia in Patients with Critical COVID-19-A Prospective Monocentric Cohort Study.

The impact of bacterial pneumonia on patients with COVID-19 infection remains unclear. This prospective observational monocentric cohort study aims to determine the incidence of bacterial community- and hospital-acquired pneumonia (CAP and HAP) and its effect on mortality in critically ill COVID-19 patients admitted to the intensive care unit (ICU) at University Hospital Olomouc between 1 November 2020 and 31 December 2022. The secondary objectives of this study include identifying the bacterial etiology of CAP and HAP and exploring the capabilities of diagnostic tools, with a focus on inflammatory biomarkers. Data were collected from the electronic information hospital system, encompassing biomarkers, microbiological findings, and daily visit records, and subsequently evaluated by ICU physicians and clinical microbiologists. Out of 171 patients suffering from critical COVID-19, 46 (27%) had CAP, while 78 (46%) developed HAP. Critically ill COVID-19 patients who experienced bacterial CAP and HAP exhibited higher mortality compared to COVID-19 patients without any bacterial infection, with rates of 38% and 56% versus 11%, respectively. In CAP, the most frequent causative agents were chlamydophila and mycoplasma; Enterobacterales, which were multidrug-resistant in 71% of cases; Gram-negative non-fermenting rods; and Staphylococcus aureus. Notably, no strains of Streptococcus pneumoniae were detected, and only a single strain each of Haemophilus influenzae and Moraxella catarrhalis was isolated. The most frequent etiologic agents causing HAP were Enterobacterales and Gram-negative non-fermenting rods. Based on the presented results, commonly used biochemical markers demonstrated poor predictive and diagnostic accuracy. To confirm the diagnosis of bacterial CAP in our patient cohort, it was necessary to assess the initial values of inflammatory markers (particularly procalcitonin), consider clinical signs indicative of bacterial infection, and/or rely on positive microbiological findings. For HAP diagnostics, it was appropriate to conduct regular detailed clinical examinations (with a focus on evaluating respiratory functions) and closely monitor the dynamics of inflammatory markers (preferably Interleukin-6).

Lipophosphonoxins-A Novel Group of Broad Spectrum Antibacterial Compounds.

Lipophosphonoxins (LPPOs) represent a new group of membrane-targeting antibiotics. Three generations of LPPOs have been described: First-generation LPPOs, second-generation LPPOs, and LEGO-LPPOs. All three generations have a similar mode of bactericidal action of targeting and disrupting the bacterial cytoplasmic membrane of prokaryotic cells, with limited effect on eukaryotic cells. First-generation LPPOs showed excellent bactericidal activity against Gram-positive species, including multiresistant strains. Second-generation LPPOs broaden the antibiotic effect also against Gram-negative bacteria. However, both first- and second-generation LPPOs lose their antibacterial activity in the presence of serum albumin. LEGO-LPPOs were found to be active against both Gram-positive and Gram-negative bacteria, have better selectivity as compared to first- and second-generation resistance to LEGO-LPPOs was also not observed, and are active even in the presence of serum albumin. Second-generation LPPOs have been studied as antimicrobial additives in bone cement and as nanofiber dressing components in the treatment of wound infections in mice. Second-generation LPPOs and LEGO-LPPOs were also tested to treat ex vivo simulated endodontic infections in dental root canals. The results of all these studies were encouraging and suggested further investigation of LPPOs in these indications. This paper aims to review and compile published data on LPPOs.

Analysis of BlaEC family class C beta-lactamase.

Recent years have witnessed an increased prevalence of intrinsic and acquired beta-lactamase-producing bacteria, severely limiting human and veterinary medicine therapeutic options. The present study aimed to design specific oligonucleotides for rapid PCR detection of the cephalosporinase-encoding gene blaEC (BlaEC family class C beta-lactamase). A total of three primers were designed to detect 2281 variants of the blaEC gene and two sets of primer pairs were also tested against DNA from 11 strains. The study indicates that the proposed primers should be able to detect 100% of all described blaEC genes in different bacterial strains and monitor their spread. After comparing the amino acid sequences, a phylogenetic tree was created based on the presence of conserved amino acids and homologous motifs. More than 24 760 mutations in BlaEC enzymes have been identified. The mutations involving 371 amino acid positions and these hotspots can change the structure and activity of the monitored enzymes. We predicted several BlaEC enzymes with a broadened substrate activity against higher-generation cephalosporins.

[Resistance of bacterial pathogens isolated from the lower respiratory tract and their clonality in intensive care patients in a post-COVID-19 period].

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.

[Pseudomonas aeruginosa virulence factors as a therapeutic target in multidrug-resistant strains].

Pseudomonas aeruginosa (PSAE) is known for its ability to form biofilm and produce other virulence factors associated with a resistant phenotype. Multidrug-resistant (MDR) PSAE strains represent a serious problem in healthcare and are the focus of an increasing number of studies dealing with the therapy of infections caused by these bacteria. Nowadays, a number of studies focus on the presence of virulence factors rather than on the mechanisms of resistance to the antibiotics used, as it is the study of virulence factors that makes it possible to expand the possibilities of effective and efficient therapy. This review describes the virulence factors produced by the one of the five PSAE secretion systems that have the potential to become targets for so-called antivirulence therapy, have been described. These are mainly alkaline protease, elastase B, exotoxins A, S and Y and pyocyanin. In addition to specific virulence factors, recent studies have focused on the components of the PSAE secretion systems that mediate the transport of toxins and lytic enzymes out of the bacterial cell. Inhibition of specific molecules for type 2 and 3 secretion systems may prevent secretion of virulence factors into the extracellular space and host cells, which would have a significant impact on reducing PSAE virulence.

Analysis of Bacterial Pathogens Causing Complicating HAP in Patients with Secondary Peritonitis.

BACKGROUND: Diffuse peritonitis is an acute abdominal condition characterized by high mortality. The main treatment modality is surgery, requiring a subsequent prolonged hospital stay. These patients are, among other things, at risk of developing hospital-acquired pneumonia (HAP), which considerably worsens their treatment outcomes. This study aimed to extend the existing knowledge by providing more detailed microbiological characteristics of complicating HAP in patients with secondary peritonitis, including the identification of isolated bacterial pathogens and their potential sources. METHODS: The 2015-2019 retrospective study comprised all patients with an intraoperatively confirmed diagnosis of secondary diffuse peritonitis who were classified in accordance with the quick Sepsis Related Organ Failure Assessment scoring system. RESULTS: HAP developed in 15% of patients. The 90-day mortality rates were 53% and 24% in patients with and without HAP; respectively. The most frequent pathogens responsible for HAP were Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae complex and Enterococcus faecalis. Multidrug resistance to antibiotics was found in 38% of bacterial pathogens. Clonal spread of these bacterial pathogens among patients was not detected. Rather, the endogenous characteristic of HAP was confirmed. CONCLUSIONS: The initial antibiotic therapy of complicating HAP in patients with secondary peritonitis must be effective mainly against enterobacteria, including strains with the production of ESBL and AmpC beta-lactamases, Pseudomonas aeruginosa and Enterococcus faecalis. The study further highlighted the importance of monitoring the respiratory tract bacterial microflora in patients with secondary peritonitis. The results should be used for initial antibiotic treatment of complicating HAP instances.

Clinical microbiology and its role in current medicine.

The characteristics of current clinical microbiology and its role in modern medicine are presented. The article defines the main objectives of microbiological examination, principles of antibiotic and diagnostic stewardship. The main emphasis is placed on the correct interpretation of microbiological results.

Infectious complications of induction treatment for acute myeloid leukaemia using the "7 + 3" protocol without antibiotic prophylaxis - 15 years of experience of one clinical site.

BACKGROUND: Infectious complications during induction chemotherapy of acute myeloid leukaemia are very common. Prophylactic use of antibiotics however is an ongoing challenge in this situation due to bacterial multi-drug resistance. The aim of this study was to provide a comprehensive overview of the incidence of infectious complications in patients with AML undergoing induction therapy using the "7+3" protocol without routine antibiotic prophylaxis at one clinical site providing specialised haematological care in the Czech Republic, over a period of 15 years. The study also evaluates the aetiological spectrum of causative agents and the development of antibiotic resistance in the context of the use of the various classes of antibiotics. The analysis includes evaluation of the importance of risk factors for infectious complications and their impact on treatment of the underlying disease. The data are compared with published figures for similar cohorts of patients. PATIENTS AND METHODS: This study presents a retrospective analysis of infectious complications in 242 patients with acute myeloid leukaemia undergoing the first cycle of induction therapy without routine antibiotic prophylaxis in one clinical site in Czech Republic during years 2006-2020. RESULTS: A total of 363 febrile episodes (FE) were recorded. At least 1 FE during the induction was detected in 229 (94.6%) patients. Clinically defined infection was the cause in 96 (26.4%) FEs and blood stream infection in 69 (19.0%) FEs. Both complications occurred simultaneously in 29 (8.0%) FEs. 169 (46.6%) FEs were evaluated as fever of unknown origin (FUO). The achievement of complete remission had a significant effect on the duration of the FE (6 vs. 9 days, P=0.0005) and on the overall survival duration (79.3 vs. 6.5 months, P<0.0001). Patients diagnosed with infection or FUO at diagnosis were significantly more likely to suffer from colonisation by multi-drug resistant bacterial strains at discharge (29.2% vs. 16.3%, P=0.022). This group of patients used antibiotic therapy for a significantly longer time (35 vs. 23 days, P<0.0001). Infection was a contributing cause of death in 18 (7.4%) patients. Mortality was significantly related to the failure to achieve complete remission (P<0.0001). CONCLUSION: Infectious mortality during induction treatment without routine antibiotic prophylaxis was comparable to the published cohorts with prophylaxis. Regular microbiology surveillance with adequate initial antibiotic treatment can compensate routine antibiotic prophylaxis with slower development of antibiotic resistance.

[Impact of the COVID-19 pandemic on antimicrobial resistance].

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.

[Digitalization in clinical microbiology].

Reflections on digitalization in clinical microbiology are presented. The advantages and limitations of digital processing of microbiological data for individuals and the human population are considered.

Breakthrough COVID-19 in Vaccinated Patients with Haematologic Malignancies-The First Single-Centre Experience from the Czech Republic.

Vaccination is an important tool in the fight against the COVID-19 pandemic in patients with haematologic malignancies. The paper provides an analysis of the course of breakthrough SARS-CoV-2 infection in a group of vaccinated patients with haematological malignancy and a comparison with a historical cohort of 96 non-vaccinated patients with haematologic malignancies and bone marrow failure syndromes (two patients) in the treatment of COVID-19. A severe or critical course of COVID-19 was significantly less frequent in the group of vaccinated patients (10.2% vs. 31.4%, p = 0.003). The need for hospitalisation due to COVID-19 was significantly lower in vaccinated patients (27.1% vs. 72.6%, p < 0.0001) and the duration of hospitalisation was significantly shorter (10 vs. 14 days, p = 0.045). Vaccinated patients were insignificantly less likely to require oxygen therapy during infection. COVID-19 mortality was significantly higher in non-vaccinated patients (15.6% vs. 5.1%, p = 0.047). The paper demonstrated a significant positive effect of vaccination against COVID-19 on a less severe clinical course of infection, lower need for hospitalisation and mortality. However, the results need to be evaluated even in the context of new antivirals and monoclonal antibodies against SARS-CoV-2 or virus mutations with different biological behaviour.

LEGO-Lipophosphonoxins: A Novel Approach in Designing Membrane Targeting Antimicrobials.

The alarming rise of bacterial antibiotic resistance requires the development of new compounds. Such compounds, lipophosphonoxins (LPPOs), were previously reported to be active against numerous bacterial species, but serum albumins abolished their activity. Here we describe the synthesis and evaluation of novel antibacterial compounds termed LEGO-LPPOs, loosely based on LPPOs, consisting of a central linker module with two attached connector modules on either side. The connector modules are then decorated with polar and hydrophobic modules. We performed an extensive structure-activity relationship study by varying the length of the linker and hydrophobic modules. The best compounds were active against both Gram-negative and Gram-positive species including multiresistant strains and persisters. LEGO-LPPOs act by first depleting the membrane potential and then creating pores in the cytoplasmic membrane. Importantly, their efficacy is not affected by the presence of serum albumins. Low cytotoxicity and low propensity for resistance development demonstrate their potential for therapeutic use.

Bacterial Resistance to Antibiotics and Clonal Spread in COVID-19-Positive Patients on a Tertiary Hospital Intensive Care Unit, Czech Republic.

This observational retrospective study aimed to analyze whether/how the spectrum of bacterial pathogens and their resistance to antibiotics changed during the worst part of the COVID-19 pandemic (1 November 2020 to 30 April 2021) among intensive care patients in University Hospital Olomouc, Czech Republic, as compared with the pre-pandemic period (1 November 2018 to 30 April 2019). A total of 789 clinically important bacterial isolates from 189 patients were cultured during the pre-COVID-19 period. The most frequent etiologic agents causing nosocomial infections were strains of Klebsiella pneumoniae (17%), Pseudomonas aeruginosa (11%), Escherichia coli (10%), coagulase-negative staphylococci (9%), Burkholderia multivorans (8%), Enterococcus faecium (6%), Enterococcus faecalis (5%), Proteus mirabilis (5%) and Staphylococcus aureus (5%). Over the comparable COVID-19 period, a total of 1500 bacterial isolates from 372 SARS-CoV-2-positive patients were assessed. While the percentage of etiological agents causing nosocomial infections increased in Enterococcus faecium (from 6% to 19%, p < 0.0001), Klebsiella variicola (from 1% to 6%, p = 0.0004) and Serratia marcescens (from 1% to 8%, p < 0.0001), there were significant decreases in Escherichia coli (from 10% to 3%, p < 0.0001), Proteus mirabilis (from 5% to 2%, p = 0.004) and Staphylococcus aureus (from 5% to 2%, p = 0.004). The study demonstrated that the changes in bacterial resistance to antibiotics are ambiguous. An increase in the frequency of ESBL-positive strains of some species (Serratia marcescens and Enterobacter cloacae) was confirmed; on the other hand, resistance decreased (Escherichia coli, Acinetobacter baumannii) or the proportion of resistant strains remained unchanged over both periods (Klebsiella pneumoniae, Enterococcus faecium). Changes in pathogen distribution and resistance were caused partly due to antibiotic selection pressure (cefotaxime consumption increased significantly in the COVID-19 period), but mainly due to clonal spread of identical bacterial isolates from patient to patient, which was confirmed by the pulse field gel electrophoresis methodology. In addition to the above shown results, the importance of infection prevention and control in healthcare facilities is discussed, not only for dealing with SARS-CoV-2 but also for limiting the spread of bacteria.

Bacterial Infections, Antimicrobial Resistance and Antibiotic Therapy.

Bacterial infections have been, and are very likely to continue to be, among the most serious problems in medicine [...].

Pulmonary Complications after COVID-19.

Coronavirus disease 2019 (COVID-19) is a threat to patients not only because of its acute course, but also because of various complications occurring in the following period, that is, more than 28 days after the onset of acute infection. The present study identified a total of 121 patients hospitalized 29 or more days after the first positive result of a PCR test for SARS-CoV-2, of whom 98 patients were included in the study. Patients were divided into two groups by the time interval between the positive COVID-19 test result and hospitalization date. The time intervals were week 5-11 in an ongoing-COVID group (57.1% of patients) and 12 or more weeks in a post-COVID-group (42.9%). The most frequent reason for hospitalization was respiratory tract infection (58.2%). Pneumonia accounted for 77.2% of these cases. Other reasons for hospitalization were interstitial lung disease (22.4%), pulmonary embolism (8.2%), and sarcoidosis (6.1%). The study group was further divided according to the causes of hospitalization into subgroups with infections and other causes. In the group with infectious diseases, there was a shorter time period between PCR positivity and hospitalization and there were significantly more frequent non-respiratory complications. In the entire sample, the in-hospital mortality was 5.1%.

Restoration of antibacterial activity of inactive antibiotics via combined treatment with a cyanographene/Ag nanohybrid.

The number of antibiotic-resistant bacterial strains is increasing due to the excessive and inappropriate use of antibiotics, which are therefore becoming ineffective. Here, we report an effective way of enhancing and restoring the antibacterial activity of inactive antibiotics by applying them together with a cyanographene/Ag nanohybrid, a nanomaterial that is applied for the first time for restoring the antibacterial activity of antibiotics. The cyanographene/Ag nanohybrid was synthesized by chemical reduction of a precursor material in which silver cations are coordinated on a cyanographene sheet. The antibacterial efficiency of the combined treatment was evaluated by determining fractional inhibitory concentrations (FIC) for antibiotics with different modes of action (gentamicin, ceftazidime, ciprofloxacin, and colistin) against the strains Escherichia coli, Pseudomonas aeruginosa, and Enterobacter kobei with different resistance mechanisms. Synergistic and partial synergistic effects against multiresistant strains were demonstrated for all of these antibiotics except ciprofloxacin, which exhibited an additive effect. The lowest average FICs equal to 0.29 and 0.39 were obtained for colistin against E. kobei and for gentamicin against E. coli, respectively. More importantly, we have experimentally confirmed for the first time, that interaction between the antibiotic's mode of action and the mechanism of bacterial resistance strongly influenced the combined treatment's efficacy.

Seroprevalence of Measles Antibodies in the Population of the Olomouc Region, Czech Republic-Comparison of the Results of Four Laboratories.

OBJECTIVES: Although the incidence of measles has decreased globally since the introduction of regular vaccination, its frequency has increased again in recent years. The study is focused on data from the Olomouc Region in the Czech Republic analyzed in four laboratories. The obtained results were compared with already published data. METHODS: The data were provided by individual laboratories in an anonymized form-age at the time of the examination, sex, and result of test. Samples were collected between June 2018 and September 2019 and evaluated on the scale positive-borderline-negative. RESULTS: A total of 7962 sera samples were evaluated using three different methods-two types of ELISA tests and CLIA. Positive result was issued in a total of 62.6 percent of samples, but the results of individual laboratories varied widely from 55.5 to 70.8 percent. However, the same trend with the highest levels of antibodies in people born before beginning of vaccination was observed. CONCLUSIONS: Data show significantly different results depending on the individual laboratories and the detection kits used. The underestimation of the proportion of positive results can cause problems in selecting individuals for revaccination with a live vaccine, which may fail in weakly positive individuals.

Ex Vivo Effect of Novel Lipophosphonoxins on Root Canal Biofilm Produced by Enterococcus faecalis: Pilot Study.

(1) Background: The root canal system has complex anatomical and histological features that make it impossible to completely remove all bacteria by mechanical means only; they must be supplemented with disinfectant irrigation. Current disinfectants are unable to eliminate certain microorganisms that persist in the root canal, resulting in treatment failure. At the Institute of Organic Chemistry and Biochemistry, Prague, novel substances with the bactericidal effect, termed lipophosphonoxins (LPPOs), have been discovered. The aim of this pilot study was to investigate the ex vivo effects of second- and third-generation LPPOs on Enterococcus faecalis and compare them with 5% sodium hypochlorite (NaOCl), 0.12% chlorhexidine digluconate, and 17% ethylenediaminetetraacetic acid (EDTA). (2) Methods: The root canal's dentin was used as a carrier for biofilm formation in the extracted human mature mandibular premolars. The samples were filled with cultivation broth and 0.25% glucose with tested solutions. In control samples, only fresh cultivation broth (negative control) and cultivation broth with bacterial suspension (growth control) were used. Each sample was inoculated with E. faecalis CCM4224 except for the negative control, and cultivation was performed. To determine the number of planktonic cells, the sample content was inoculated on blood agar. To evaluate biofilm formation inhibition, samples were placed in tubes with BHI. (3) Results: LPPOs exhibited a reduction in biofilm growth and bacteria comparable to NaOCl, and they were superior to other tested disinfectants. (4) Conclusions: The study results suggest the effect of lipophosphonoxins on E. faecalis CCM 4224 reduces planktonic bacterial cells and inhibits formation of biofilm in root canal samples.

Prevalence of Vancomycin-Resistant Enterococci and Antimicrobial Residues in Wastewater and Surface Water.

Due to the extensive use of antimicrobial agents in human and veterinary medicine, residues of various antimicrobials get into wastewater and, subsequently, surface water. On the one hand, a combination of processes in wastewater treatment plants aims to eliminate chemical and biological pollutants; on the other hand, this environment may create conditions suitable for the horizontal transfer of resistance genes and potential selection of antibiotic-resistant bacteria. Wastewater and surface water samples (Morava River) were analyzed to determine the concentrations of 10 antibiotics and identify those exceeding so-called predicted no-effect environmental concentrations (PNECs). This study revealed that residues of five of the tested antimicrobials, namely ampicillin, clindamycin, tetracycline, tigecycline and vancomycin, in wastewater samples exceeded the PNEC. Vancomycin concentrations were analyzed with respect to the detected strains of vancomycin-resistant enterococci (VRE), in which the presence of resistance genes, virulence factors and potential relationship were analyzed. VRE were detected in 16 wastewater samples (11%) and two surface water samples (6%). The PNEC of vancomycin was exceed in 16% of the samples. Since the detected VRE did not correlate with the vancomycin concentrations, no direct relationship was confirmed between the residues of this antimicrobials and the presence of the resistant strains.

Clostridioides difficile and Vancomycin-Resistant Enterococci in COVID-19 Patients with Severe Pneumonia.

Broad-spectrum antibiotics administered to patients with severe COVID-19 pneumonia pose a risk of infection caused by Clostridioides difficile. This risk is reduced mainly by strict hygiene measures and early de-escalation of antibiotic therapy. Recently, oral vancomycin prophylaxis (OVP) has also been discussed. This retrospective study aimed to assess the prevalence of C. difficile in critical COVID-19 patients staying in an intensive care unit of a tertiary hospital department of anesthesiology, resuscitation, and intensive care from November 2020 to May 2021 and the rates of vancomycin-resistant enterococci (VRE) after the introduction of OVP and to compare the data with those from controls in the pre-pandemic period (November 2018 to May 2019). During the COVID-19 pandemic, there was a significant increase in toxigenic C. difficile rates to 12.4% of patients, as compared with 1.6% in controls. The peak rates were noted in February 2021 (25% of patients), immediately followed by initiation of OVP, changes to hygiene precautions, and more rapid de-escalation of antibiotic therapy. Subsequently, toxigenic C. difficile detection rates started to fall. There was a nonsignificant increase in VRE detected in non-gastrointestinal tract samples to 8.9% in the COVID-19 group, as compared to 5.3% in the control group. Molecular analysis confirmed mainly clonal spread of VRE.