Clostridioides difficile infection epidemiology during the COVID-19 pandemic in Greece.

Aim: The aim was to highlight the incidence and epidemiology of C. difficile infections (CDI) in a tertiary Greek hospital during the COVID-19 pandemic. Methods: A single-center prospective observational cohort study was conducted (October 2021 until April 2022). 125 C. difficile isolates were cultured from hospitalized patients stool samples and screened by PCR for toxin A (tcdA), toxin B (tcdB), binary toxin (cdtA and cdtB) genes and the regulating gene of tcdC. Results: The incidence of CDI increased to 13.1 infections per 10,000 bed days. The most common PCR ribotypes identified included hypervirulent RT027-related RT181 (73.6%), presumably hypervirulent RT126 (8.0%) and toxin A negative RT017 (7.2%). Conclusion: Although the incidence of CDI increased significantly, the CDI epidemiology remained stable.

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Pan-Genome Plasticity and Virulence Factors: A Natural Treasure Trove for Acinetobacter baumannii.

Acinetobacter baumannii is a Gram-negative pathogen responsible for a variety of community- and hospital-acquired infections. It is recognized as a life-threatening pathogen among hospitalized individuals and, in particular, immunocompromised patients in many countries. A. baumannii, as a member of the ESKAPE group, encompasses high genomic plasticity and simultaneously is predisposed to receive and exchange the mobile genetic elements (MGEs) through horizontal genetic transfer (HGT). Indeed, A. baumannii is a treasure trove that contains a high number of virulence factors. In accordance with these unique pathogenic characteristics of A. baumannii, the authors aim to discuss the natural treasure trove of pan-genome and virulence factors pertaining to this bacterial monster and try to highlight the reasons why this bacterium is a great concern in the global public health system.

Infection control measures against multidrug-resistant Gram-negative bacteria in children and neonates.

The increase in infections caused by multidrug-resistant (MDR) Gram-negative bacteria in neonatal and pediatric intensive care units over recent years is alarming. MDR Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii have constituted the main causes of the MDR Gram-negative bacteria problem. The implementation of infection control measures such as hand hygiene, cohorting of patients, contact precautions, active surveillance and environmental cleaning could diminish their spread. Recently, water safety has been identified as a major component of infection control policies. The aim of the current review is to highlight the effectiveness of these infection control measures in managing outbreaks caused by MDR Gram-negative bacteria in neonatal and pediatric intensive care units and highlight future perspectives on the topic.

Efficacy of antimicrobials or placebo compared to amoxicillin-clavulanate in children with acute otitis media: a systematic review.

BACKGROUND: Acute otitis media (AOM) is the inflammation of the middle ear. It constitutes one of the most frequent infections which affects children and usually occurs between 6 to 24 months of age. AOM can emerge due to viruses and/or bacteria. The aim of the current systematic review is to assess in children between 6 months and 12 years of age with AOM, the efficacy of any antimicrobial agent or placebo compared with amoxicillinclavulanate, to measure the resolution of AOM or symptoms. METHODS: The medical databases PubMed (MEDLINE) and Web of Science were used. Data extraction and analysis were performed by two independent reviewers. Eligibility criteria were set, and only randomised control trials (RCTs) were included. Critical appraisal of the eligible studies was performed. Pooled analysis was conducted using the Review Manager v. 5.4.1 software (RevMan). RESULTS: Twelve RCTs were totally included. Three (25.0%) RCTs studied the impact of azithromycin, two (16.7%) investigated the impact of cefdinir, two (16.7%) investigated placebo, three (25.0%) studied quinolones, one (8.3%) investigated cefaclor and one (8.3%) studied penicillin V, compared to amoxicillin-clavulanate. In five (41.7%) RCTs, amoxicillin-clavulanate proved to be superior to azithromycin, cefdinir, placebo, cefaclor and penicillin V, while in seven (58.3%) RCTs its efficacy was comparable with other antimicrobials or placebo. The rates of AOM relapse after treatment with amoxicillin-clavulanate were comparable to those of other antimicrobials or placebo. However, amoxicillin-clavulanate was more effective in eradicating Streptococcus pneumoniae from the culture, when compared to cefdinir. The results of the meta-analysis were not evaluated due to substantial heterogeneity between studies. CONCLUSIONS: Amoxicillin-clavulanate should be the treatment of choice for children between 6 months and 12 years of age with AOM.

Implication of COVID-19 pandemic on the incidence of Clostridioides difficile infection in a Greek tertiary hospital.

Introduction. C. difficile infection (CDI) represents an important global threat. In the COVID-19 era, the multifactorial nature of CDI has emerged.Hypothesis - Aim. The aim was to assess the impact of COVID-19 pandemic on the incidence of CDI in a Greek hospital.Methodology. A retrospective study was performed throughout a 51 month period (January 2018 to March 2022), divided into two periods: pre-pandemic (January 2018 to February 2020) and COVID-19 pandemic (March 2020 to March 2022). The effects of the pandemic compared to the pre-pandemic period on the incidence of CDI [expressed as infections per 10 000 bed days (IBD)] were studied using interrupted time-series analysis.Results. Throughout the study, there was an increase in the monthly CDI incidence from 0.00 to 11.77 IBD (P<0.001). Interrupted time-series disclosed an increase in CDI incidence during the pre-pandemic period from 0.00 to 3.36 IBD (P<0.001). During the COVID-19 pandemic period the linear trend for monthly CDI rose from 2.65 to 13.93 IBD (P<0.001). The increase rate was higher during the COVID-19 pandemic period (r2 = +0.47) compared to the pre-pandemic period (r1 = +0.16).Conclusion. A significant increase of CDI incidence was observed, with the rate of the rise being more intense during the COVID-19 pandemic.

Efficacy and safety of ceftazidime-avibactam compared to other antimicrobials for the treatment of infections caused by carbapenem-resistant Klebsiella pneumoniae strains, a systematic review and meta-analysis.

INTRODUCTION: Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are a significant public health issue. CRKP infections can increase the mortality of severely ill hospitalised patients and elevate the financial burden of their hospitalisation globally. Colistin and tigecycline are the main antimicrobials which have been widely used for the treatment of CRKP infections. However, novel antimicrobials have been recently launched. Ceftazidime-avibactam (CAZ-AVI) seems one of the most efficient ones. AIM: The aim of the current systematic literature review and meta-analysis is to assess the efficacy and safety of CAZ-AVI compared to other antimicrobials in adult patients (aged >18) with CRKP infection. METHODS: All data were retrieved using PubMed/Medline, the Web of Science and Cochrane library. The main outcome was the effective treatment of CRKP infection or the microbiological eradication of CRKP in the culture of biological samples. Secondary outcomes included the impact on 28- or 30-day mortality and adverse effects, if available. Pooled analysis was conducted using Review Manager v. 5.4.1 software (RevMan). The level of statistical significance was set at p < 0.05. RESULTS: CAZ-AVI was proved more effective than other antimicrobials against CRKP infections and CRKP bloodstream infections (p < 0.00001 and p < 0.0001, respectively). Patients in the CAZ-AVI arm displayed statistically lower 28- and 30-day mortality rates (p = 0.002 and p < 0.00001, respectively). Concerning the microbiological eradication, no meta-analysis was feasible due to high heterogeneity. CONCLUSION: The promotion of CAZ-AVI for treating CRKP infections over other antimicrobials seems favourable. However, there is a long way ahead to reveal additional scientific findings to further strengthen this statement.

Carbapenem-Resistant Klebsiella pneumoniae: Virulence Factors, Molecular Epidemiology and Latest Updates in Treatment Options.

Klebsiella pneumoniae is a Gram-negative opportunistic pathogen responsible for a variety of community and hospital infections. Infections caused by carbapenem-resistant K. pneumoniae (CRKP) constitute a major threat for public health and are strongly associated with high rates of mortality, especially in immunocompromised and critically ill patients. Adhesive fimbriae, capsule, lipopolysaccharide (LPS), and siderophores or iron carriers constitute the main virulence factors which contribute to the pathogenicity of K. pneumoniae. Colistin and tigecycline constitute some of the last resorts for the treatment of CRKP infections. Carbapenemase production, especially K. pneumoniae carbapenemase (KPC) and metallo-ß-lactamase (MBL), constitutes the basic molecular mechanism of CRKP emergence. Knowledge of the mechanism of CRKP appearance is crucial, as it can determine the selection of the most suitable antimicrobial agent among those most recently launched. Plazomicin, eravacycline, cefiderocol, temocillin, ceftolozane-tazobactam, imipenem-cilastatin/relebactam, meropenem-vaborbactam, ceftazidime-avibactam and aztreonam-avibactam constitute potent alternatives for treating CRKP infections. The aim of the current review is to highlight the virulence factors and molecular pathogenesis of CRKP and provide recent updates on the molecular epidemiology and antimicrobial treatment options.

Spa diversity and genetic characterization of t127 methicillin-resistant Staphylococcus aureus in a tertiary Greek hospital.

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) causes severe community and hospital acquired infections. Identification of staphylococcal cassette chromosome mec (SCCmec), multilocus-sequence typing, and sequencing of S. aureus protein A (spa) gene are used for MRSA typing. The aim was to investigate the spa types of MRSA isolates in a tertiary hospital in Greece and analyse the whole genome sequences of two t127 MRSA isolates. Methods: Totally, 39 MRSA isolates collected from July 2019 to June 2020 in "Georgios Gennimatas" General Hospital of Thessaloniki, Greece, were included in the study. Identification and antimicrobial susceptibility testing were performed using VITEK II automated system, and spa typing was performed. A minimum spanning tree was used to display the spa type frequencies and the genetic distances among them. Two t127-MRSA isolates (IM-MRSA and PD-MRSA) were selected for WGS. Results: Six isolates (15.4%) were resistant to mupirocin, 18 (46.2%) to fusidic acid, three (7.7%) to vancomycin and two (5.1%) to teicoplanin. Twenty-two different spa types were detected, with t002, t003, and t422 being the most frequent (5/39, 12.8% each), followed by t1994 (4/39, 10.3%). The isolates presented high genetic diversity and, taking into account the time between hospital admission and sampling, intrahospital spread did not occur. Even the two t127 isolates were assigned to different sequence types, ST9-XII-t127 and ST1-IVa-t127. Plasmids and genes conferring antimicrobial resistance and virulence were also identified. Conclusions: Various spa types were identified and together with the information about the time between hospital admission and sampling supports polyclonal MRSA spread in the hospital excluding a nosocomial infection. WGS provides a more detailed analysis distinguishing even the isolates belonging to the same spa type.

Genetic characterization of livestock-associated methicillin-resistant Staphylococcus aureus isolated in Greece.

The interest in livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) strains is increasing due to their wide distribution and transmission even in persons without previous contact with livestock, and these strains pose a public health threat. The aim of the study was the genetic characterization of the whole genome of two epidemiologically unrelated t034 LA-MRSA strains previously isolated from the nasal cavities of a goat and a farmer in Greece. Both strains were assigned to the ST398-Vc-t034 type and they were carrying a single transposon identical to Tn6133. They harbored genes conferring resistance to several antibiotics (aminoglycosides, ß-lactams, macrolides, streptogramin B, tetracycline, and trimethoprim), and genes associated with virulence (enterotoxins, γ-hemolysins, and aureolysin). The present study can serve as baseline for further LA-MRSA epidemiological and evolutionary studies in Greece, while awareness and increased surveillance are needed to avoid their spread.

Genetic characterization of two methicillin-resistant Staphylococcus aureus spa type t127 strains isolated from workers in the dairy production chain in Greece.

Methicillin-resistant Staphylococcus aureus (MRSA) constitutes a constant threat for the public health. Aim of the present study was to analyse the whole genome sequences of two MRSA strains belonging to Staphylococcus protein A (spa) type t127 isolated from humans working in two distantly located dairy production farms in Greece.MRSA strains were isolated from the nasal cavity of a food handler in a milk industry in Epirus, northwestern Greece (E-MRSA), and a person working in a cattle farm in Thrace, northeastern Greece (T-MRSA). Whole genome sequences taken using next generation sequencing were analysed for resistance and virulence genes applying various bioinformatic tools.Both isolates were assigned to ST1-IVa-t127 type, and they were transferring genes conferring resistance to tetracycline, ß-lactams, and aminoglycosides; T-MRSA was carrying additional genes leading to macrolide, lincosamide and streptogramin B (MLSB) resistance. Both isolates were carrying three plasmid replicon types, rep5, rep7 and rep16, while T-MRSA harboured also rep10 and rep15. E-MRSA carried scn and sak genes which were absent from T-MRSA.In conclusion, the genetic characterization of two unrelated ST1-IVa-t127 MRSA strains isolated from humans in close contact with livestock in Greece can be used as basis for further epidemiological and evolutionary studies.

Forecasting models of infections due to carbapenem-resistant Gram-negative bacteria in an intensive care unit in an endemic area.

OBJECTIVES: The aim of this study was to forecast the monthly incidence rates of infections [infections/1000 bed-days (IBD)] due to carbapenem-resistant Klebsiella pneumoniae (CRKP), carbapenem-resistant Pseudomonas aeruginosa (CRPA), carbapenem-resistant Acinetobacter baumannii (CRAB) and total carbapenem-resistant Gram-negative bacteria (CRGNB) in an endemic intensive care unit (ICU) during the subsequent year (December 2016-December 2017) following the observational period. METHODS: A 52-month observational period (August 2012-November 2016) was used. Two forecasting models, including a simple seasonal model for CRGNB, CRKP and CRPA and Winters' additive model for CRAB infections, were applied. RESULTS: The models predicted the highest infection rates for CRKP, CRAB and CRGNB in January and September 2017 (23.8/23.4, 24.6/28.5 and 46.8/46.7 IBD, respectively) and for CRPA in February and March 2017 (8.3 and 7.9, respectively). The highest observed rates for CRKP, CRAB and CRGNB were indeed in January and September 2017 (25.6/19.0, 34.2/23.8 and 59.8/42.8 IBD, respectively); and for CRPA in February and March of the same year (15.2 and 12.7, respectively). The increased rates may be associated with personnel's annual work programme and behavioural factors. CONCLUSION: Forecasting models in endemic ICUs may assist in implementation strategies for infection control measures.

Effects of an Active Surveillance Program and Enhanced Infection Control Measures on Carbapenem-Resistant Gram-Negative Bacterial Carriage and Infections in Pediatric Intensive Care.

We evaluated the effects of enhanced infection control measures (ICMs) on carriage and infections of carbapenem-resistant Gram-negative bacteria (CRGNB) in a pediatric intensive care unit. We conducted a quasi-experimental study, including patients with infections of CRGNB retrospectively for 13 months and those participating in an active surveillance program prospectively for 22 months. Active surveillance (weekly rectal swabs) was implemented during a 63-week subperiod with standard ICMs and a subsequent 27-week subperiod with enhanced ICMs (intensified ICMs supplemented with audits and feedback). Prevalence, colonization pressure, incidence, and infections of CRGNB and compliance with ICMs and enhanced ICMs were recorded. Evaluation of results was performed using time series (TS) and interrupted TS. Compliance with hand hygiene improved during the second subperiod of active surveillance compared with the first; prevalence, colonization pressure, and incidence of CRGNB decreased significantly. The linear trend of centered moving average for carbapenem-resistant Klebsiella pneumoniae (CRKP) decreased from 1.2 to 0.1 infections/1,000 bed-days (IBD) (p = 0.046), while it remained unchanged for carbapenem-resistant Acinetobacter baumannii (CRAB) and increased for carbapenem-resistant Pseudomonas aeruginosa (CRPA) from 0.0 to 2.1 IBD (p < 0.001). Enhanced ICMs can reduce CRKP infections in endemic units, in contrast to CRPA and CRAB infections, which are more difficult to eradicate.

Polyclonal predominance of concurrently producing OXA-23 and OXA-58 carbapenem-resistant Acinetobacter baumannii strains in a pediatric intensive care unit.

We report a predominance (64.7%) of polyclonal carbapenem-resistant Acinetobacter baumannii (CRAB) strains concurrently producing OXA-23 and OXA-58 carbapenemases in a pediatric intensive care unit in an endemic area. This is the first report of emergence of such double-OXA CRAB strains in a single unit worldwide.

Comparison of semiquantitative and differential time to positivity methods for the diagnosis of central line-associated bloodstream infections in an intensive care unit.

INTRODUCTION: Central line-associated bloodstream infections (CLABSIs) adversely affect patients' hospitalization. AIM: We compared semiquantitative roll plate (SQRP) and differential time to positivity (DTP) culture methods in diagnosing CLABSIs. METHODOLOGY: A retrospective study was conducted in an intensive care unit (ICU) from January 2013 to August 2014. All ICU patients with suspected CLABSIs were included. Blood cultures were taken, while central venous catheter (CVC) tips were cultured using the roll-tip method. DTP was considered positive if CVC lumen blood cultures became positive at least 2 h prior to concurrently drawn peripheral blood cultures with an identical micro-organism. SQRP method was considered positive when ≥15 c.f.u. of a micro-organism identical to that of blood cultures grew. Measures of diagnostic accuracy were calculated. RESULTS: SQRP displayed high sensitivity (94.7 %), while DTP showed high specificity (82.5 %). SQRP combined with DTP displayed 100  % sensitivity and negative predictive value. CONCLUSION: SQRP and DTP methods should be evaluated in combination.

Respiratory Syncytial Virus in Greece, 2016-2018.

Human respiratory syncytial virus (RSV) is the leading cause of acute bronchiolitis in infants and young children. Children under the age of 2 years, hospitalized for bronchiolitis in the pediatric clinic of a tertiary hospital in northern Greece, were tested for RSV infection during two RSV seasons (2016-2017 and 2017-2018). RSV was detected in 37 of 71 (52.1%) patients, most of them younger than 6 months. Both RSV subtypes were detected - RSV-A (54.1%) and RSV-B (45.9%) - with predominance of RSV-A during the 2016-2017 and RSV-B during the 2017-2018 season. RSV-A and RSV-B sequences clustered within the ON1 and BA genotypes, respectively. Compared to the prototype strains, several amino acid substitutions were observed in the duplication region of the G gene. The study provides a first insight into the molecular epidemiology of RSV in Greece.

Molecular Epidemiology of Endemic Carbapenem-Resistant Gram-Negative Bacteria in an Intensive Care Unit.

The molecular epidemiology of endemic carbapenem-resistant Klebsiella pneumoniae (CRKP), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and carbapenem-resistant Acinetobacter baumannii (CRAB) in an intensive care unit located in an endemic area with high rates of resistance was investigated. A CRPA strain producing VIM and KPC concurrently was detected for the first time in an endemic area. CRKP strains producing K. pneumoniae carbapenemase predominated and were mainly assigned to the "hyperepidemic Greek clone." Predominant OXA-23-like producing CRAB strains were assigned to multiple pulsotypes.

Molecular epidemiology of Dobrava-Belgrade virus in Greece.

In order to gain an insight into the genetic relatedness of the Dobrava-Belgrade virus (DOBV) in Greece, a phylogenetic analysis was performed based on all currently available DOBV sequences obtained from hospitalized cases with hemorrhagic fever with renal syndrome (HFRS). Most cases occurred in northwestern and north central part of the country. Two sequence datasets consisted of 41 S and 12 M partial DOBV RNA segment sequences were analyzed. All DOBV strains belong to Dobrava genotype which is associated with the rodent Apodemus flavicollis. In both phylogenetic trees (S and M segments), two main clusters of Greek strains could be distinguished. Phylogenetic analysis showed a spatial rather than temporal relation of the strains, since their genetic clustering was highly associated with the geographic distribution of the cases. Besides previous characterized endemic foci, novel ones have been identified, expanding our knowledge on the epidemiology of HFRS in Greece.

Crimean-Congo Hemorrhagic Fever: Tick-Host-Virus Interactions.

Crimean-Congo hemorrhagic fever virus (CCHFV) is transmitted to humans by bite of infected ticks or by direct contact with blood or tissues of viremic patients or animals. It causes to humans a severe disease with fatality up to 30%. The current knowledge about the vector-host-CCHFV interactions is very limited due to the high-level containment required for CCHFV studies. Among ticks, Hyalomma spp. are considered the most competent virus vectors. CCHFV evades the tick immune response, and following its replication in the lining of the tick's midgut, it is disseminated by the hemolymph in the salivary glands and reproductive organs. The introduction of salivary gland secretions into the host cells is the major route via which CCHFV enters the host. Following an initial amplification at the site of inoculation, the virus is spread to the target organs. Apoptosis is induced via both intrinsic and extrinsic pathways. Genetic factors and immune status of the host may affect the release of cytokines which play a major role in disease progression and outcome. It is expected that the use of new technology of metabolomics, transcriptomics and proteomics will lead to improved understanding of CCHFV-host interactions and identify potential targets for blocking the CCHFV transmission.

Impaired glucose metabolism and bronchial hyperresponsiveness in obese prepubertal asthmatic children.

INTRODUCTION: The prevalence of asthma and obesity has risen in parallel over the last decades, but the exact mechanisms linking these two diseases still remain unclear. The aim of the present study was to investigate the associations between bronchial hyperresponsiveness (BHR), impaired glucose metabolism, obesity, and asthma in prepubertal children. METHODS: A total of 71 prepubertal children were included in the study and divided in four groups according to the presence of asthma and their Body Mass Index (BMI): Group 1-Healthy Controls (HC), Group 2-Non Obese Asthmatics (NOA), Group 3-Obese Non Asthmatics (ONA), Group 4-Obese Asthmatics (OA) Αll children underwent spirometry and bronchial hyperresponsiveness testing by using the cumulative Provoking Dose of mannitol (PD15, primary study variable); homeostasis model assessment-estimated insulin resistance (HOMA-IR) index was calculated in order to evaluate insulin resistance. Obese children also underwent an oral glucose tolerance testing (OGTT). RESULTS: A statistically significant difference in bronchial hyperreactivity (mean ± SD) was detected in the group of obese asthmatic children who had lower values ​​of PD15 , (174.16 ± 126.42) as compared to normal weight asthmatic children (453.93 ± 110.27), (P < 0.001). Moreover, obese asthmatic children with confirmed insulin resistance (HOMA-IR ≥2.5), had significantly lower PD15 values (89.05 ± 42.75) as ​​compared to those with HOMA-IR <2.5 (259.27 ± 125.75), (P = 0.006). Finally, obese asthmatic children with impaired OGTT had likewise significantly lower PD15 (81.02 ± 42.16) measurements as compared to children with normal OGTT (267.3 ± 112.62), (P = 0.001). CONCLUSION: Our findings suggest that obesity per se does not correlate to airway hyperreactivity unless it is accompanied by glucose intolerance and insulin resistance. Pediatr Pulmonol. 2017;52:160-166. © 2016 Wiley Periodicals, Inc.

Immune response in Dobrava-Belgrade virus infections.

Dobrava-Belgrade virus (DOBV) is a hantavirus that causes a disease in humans known as hemorrhagic fever with renal syndrome. Hallmarks of hantaviral infections are increased vascular permeability due to dysregulation of the endothelial cell barrier and acute thrombocytopenia. In order to gain insight into the immune response in DOBV infections, the serum levels of 27 cytokines in 24 hospitalized Greek HFRS patients were evaluated. Compared to the control group, significantly higher IL-1ra, IL-6, IL-8, IL-9, IL-10, GM-CSF, IP-10, MIP-1b, TNF-α and VEGF levels were found in severe cases, while in non-severe cases, IL-13 and TNF-α levels were significantly higher (p < 0.05). In all groups, IP-10 was increased and RANTES was decreased. Significant and time- (after onset of illness) dependent differences among fatal, severe and non-severe cases were seen. VEGF was positively associated with disease severity. A strong immune response was seen during the first week of illness, especially in severe cases, while the response in non-severe cases was weaker and delayed. The Th1 response was strong in non-severe cases and weak in the fatal case, while a mixed Th1/Th2 immune response was seen in the survivors of severe disease.