In vitro activities of omadacycline, eravacycline, cefiderocol, apramycin, and comparator antibiotics against Acinetobacter baumannii causing bloodstream infections in Greece, 2020-2021: a multicenter study.

Resistance of Acinetobacter baumannii to multiple clinically important antimicrobials has increased to very high rates in Greece, rendering most of them obsolete. The aim of this study was to determine the molecular epidemiology and susceptibilities of A. baumannii isolates collected from different hospitals across Greece. Single-patient A. baumannii strains isolated from blood cultures (n = 271), from 19 hospitals, in a 6-month period (November 2020-April 2021) were subjected to minimum inhibitory concentration determination and molecular testing for carbapenemase, 16S rRNA methyltransferase and mcr gene detection and epidemiological evaluation. 98.9% of all isolates produced carbapenemase OXA-23. The vast majority (91.8%) of OXA-23 producers harbored the armA and were assigned mainly (94.3%) to sequence group G1, corresponding to IC II. Apramycin (EBL-1003) was the most active agent inhibiting 100% of the isolates at ≤16 mg/L, followed by cefiderocol which was active against at least 86% of them. Minocycline, colistin and ampicillin-sulbactam exhibited only sparse activity (S <19%), while eravacycline was 8- and 2-fold more active than minocycline and tigecycline respectively, by comparison of their MIC50/90 values. OXA-23-ArmA producing A. baumannii of international clone II appears to be the prevailing epidemiological type of this organism in Greece. Cefiderocol could provide a useful alternative for difficult to treat Gram-negative infections, while apramycin (EBL-1003), the structurally unique aminoglycoside currently in clinical development, may represent a highly promising agent against multi-drug resistant A. baumanni infections, due to its high susceptibility rates and low toxicity.

Serum Proteome Signatures of Anti-SARS-CoV-2 Vaccinated Healthcare Workers in Greece Associated with Their Prior Infection Status.

Over the course of the pandemic, proteomics, being in the frontline of anti-COVID-19 research, has massively contributed to the investigation of molecular pathogenic properties of the virus. However, data on the proteome on anti-SARS-CoV-2 vaccinated individuals remain scarce. This study aimed to identify the serum proteome characteristics of anti-SARS-CoV-2 vaccinated individuals who had previously contracted the virus and comparatively assess them against those of virus-naïve vaccine recipients. Blood samples of n = 252 individuals, out of whom n = 35 had been previously infected, were collected in the "G. Gennimatas" General Hospital of Thessaloniki, from 4 January 2021 to 31 August 2021. All participants received the BNT162b2 mRNA COVID-19 vaccine (Pfizer/BioNTech). A label-free quantitative proteomics LC-MS/MS approach was undertaken, and the identified proteins were analyzed using the GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes) databases as well as processed by bioinformatics tools. Titers of total RBD-specific IgGs against SARS-CoV-2 were also determined using the SARS-CoV-2 IgG II Quant assay. A total of 47 proteins were significantly differentially expressed, the majority of which were down-regulated in sera of previously infected patients compared to virus-naïve controls. Several pathways were affected supporting the crucial role of the humoral immune response in the protection against SARS-CoV-2 infection provided by COVID-19 vaccination. Overall, our comprehensive proteome profiling analysis contributes novel knowledge of the mechanisms of immune response induced by anti-SARS-CoV-2 vaccination and identified protein signatures reflecting the immune status of vaccine recipients.

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.

The role of the sequential organ failure assessment score in evaluating the outcome in dogs with parvoviral enteritis.

SCIENTIFIC BACKGROUND: The aim of this prospective study was to assess whether the Sequential Organ Failure Assessment (SOFA) score could be indicative of outcome (survival to discharge) in dogs with parvoviral enteritis. METHODS: In 35 naturally infected dogs, the SOFA score and clinical score were calculated and the presence of systemic inflammatory response syndrome was verified on admission and during the first four days of hospitalization. RESULTS: 26 dogs survived, and out of the 9 non-survivors, 6 dogs had positive blood cultures. Mean SOFA scores and clinical scores between survivors and non-survivors and between septic and non-septic dogs on admission and on each hospitalization day were significantly different. Trends in SOFA score indicated that in non-survivors and septic dogs there was an increase in SOFA score during the first four days of hospitalization and a decrease occurred in survivors and non-septic dogs. The area under the curve (ROC curve analysis) for SOFA score predicting the outcome was 0.797 and predicting sepsis was 0.834. The best cut-off point of SOFA score for predicting the final outcome was 3.5 and the best cut-off of SOFA score for predicting sepsis was also 3.5. CONCLUSIONS: Either single values or trends in SOFA score can assist in suspecting sepsis and reaching prognosis in parvoviral enteritis.

Significant Increase in Antibody Titers after the 3rd Booster Dose of the Pfizer-BioNTech mRNA COVID-19 Vaccine in Healthcare Workers in Greece.

The aim of our study was to assess the immunogenicity of the third dose of the BNT162b2 mRNA COVID-19 vaccine (Comirnaty) in a cohort of 129 health-care workers in Greece whose anti-S1 RBD IgG titers were monitored over the course of nine months. Titers were measured for each participant just before the third dose (nine months after the second dose) and also one month after the third dose. Of the 129 participants, 19 had been previously infected before starting the vaccination scheme. The SARS-CoV-2 IgG II Quant assay on the Architect System was employed to longitudinally assess the titers of IgG against the receptor-binding domain of the S1 subunit of the spike protein (anti-S1 RBD). Boosters raised Geometric Mean Concentrations (GMCs) by a factor of approximately 47 relative to levels at 9 months and by a factor of approximately 23 relative to levels at 6 months. The immune response one month after the third dose was significantly higher than the response achieved one month after the second dose (p = 0.008). In conclusion, our findings verify the potent immunogenicity elicited by the third dose in all age and prior COVID-19 status groups, suggesting that the timely administration of the third (booster) dose maximizes the immunogenic potential of the vaccine.

Antibody titers after a third dose of the SARS-CoV-2 BNT162b2 vaccine in immunocompromised adults in Greece: Is a fourth dose necessary?

Real-world data suggest that protection against COVID-19 declines a few months after vaccination, particularly in the elderly and immunocompromised individuals. Our study aimed to analyze the humoral response induced by a third supplemental dose of BNT162b2 vaccine in a mixed group of immunocompromised individuals by determining anti-spike (anti-S) IgG antibody titers at baseline (pre-third vaccine dose) and 4 weeks after the dose. Serum samples were obtained from a total group of 85 immunocompromised individuals (history of cancer: n = 20, lymphoma: n = 4, leukemia: n = 3, transplant recipients: n = 4, autoimmune disease: n = 42, inflammatory disease: n = 6, autoimmune diabetes type 1: n = 6) all of whom had previously received a two-dose schedule of the vaccine. The average number of days between second and third dose was 139.6145 (±41.39071). The overall IgG GMCs 4 weeks postvaccination were increased by more than 35 times (fold change = 35.30, p < 0.001). Fold changes were not significantly correlated with underlying condition, age, sex nor with days between second and third dose. Considering the predominance of omicron variants in the current period and the results of studies showing a decrease in the effectiveness of the third dose after 10 weeks we highly recommend a fourth dose to this vulnerable population group.

Immunogenicity of the BNT162b2 mRNA Covid-19 vaccine in elderly people over 85 years of age in Greece: the GREVAXIMO study.

BACKGROUND: Elderly people aged over 85 years were among the first groups to receive the BNT162b2 mRNA Covid-19 vaccine in Greece according to the national priority assignment policy. AIM: The aim of this study was to provide useful insight into the antibody generation taking place post-immunization in elderly individuals aged over 85. METHODS: In the first phase of our study, antibody levels were monitored in a total of 400 participants, while our final sample consisted of 297 subjects. Humoral immune responses were recorded in 69.75% (95% CI 65.25-74.25) of vaccinees post-first dose and in 98.99% (95% CI 97.85-100) post-second dose. RESULTS: Overall, a remarkable 40-fold change in IgG levels was observed between the two doses. Subjects displaying low antibody levels after the first dose had significantly higher IgG fold changes than vaccinees whose initial antibody levels were high. CONCLUSION: Taken together, our findings highlighted the high fold change (41.18) recorded in the titers of neutralizing antibodies after the second dose suggesting the need for its timely administration to elderly individuals.

Immunogenicity after the first dose of the BNT162b2 mRNA Covid-19 vaccine: real-world evidence from Greek healthcare workers.

Real-world data regarding the effectiveness, safety and immunogenicity of the Pfizer-BioNTech BNT162b2 mRNA vaccine are accumulating in the literature, suggesting that this vaccine generates high titres of S1-binding IgG antibodies that exhibit potent virus neutralization capacity. This is the first phase IV immunogenicity study to recruit a large number of Greek healthcare workers (n=425) including 63 previously-infected subjects. We measured titres of neutralizing IgGs against the receptor-binding domain of the S1 subunit of the spike protein of SARS-CoV-2 14 days post-immunization with the first dose, employing the SARS-CoV-2 IgG II Quant assay. A total of 92.24 % of our study cohort received a positive assay outcome and titres varied with age. Post-hoc analysis revealed that although titres did not significantly differ among participants aged 20-49 years, a significant decline was marked in the age group of 50-59 years, which was further accentuated in subjects aged over 60. Antibody titres escalated significantly among the previously-infected, indicating the potential booster effect of the first dose in that group.

Second dose of the BNT162b2 mRNA vaccine: Value of timely administration but questionable necessity among the seropositive.

This study monitored titers of neutralizing IgG against the receptor-binding domain of the SARS-CoV-2 S1 subunit 14 days post-injection of each dose of the BNT162b2 mRNA Covid-19 vaccine in 401 Greek healthcare workers aged 20-67. After the first dose, titers varied upon age and history of infection, being lower in the 50+ age group and significantly higher among the seropositive. After the second dose, immunogenicity was significantly boosted in the age 50+ and SARS-CoV-2-naïve individuals, indicating the effectuality of its timely administration, yet questioning its value among the seropositive.

Is intestinal stasis sufficient by itself in promoting enterocolitis in a non-genetic rat model of Hirschsprung's disease?

BACKGROUND: Hirschsprung's disease-associated enterocolitis (HE) is a life-threatening septic complication of Hirschsprung's disease (HD), leading to bacterial translocation (BT) and sepsis. Many factors, such as intestinal stasis, HD-related inherited immune disorders and abnormal mucosal secretion have been implicated in its pathogenesis. OBJECTIVES: To investigate the effect of intestinal stasis as an independent factor in the pathogenesis of HE intestinal lesions and its systematic effects. MATERIAL AND METHODS: The rectal ganglion cells of 46 Wistar rats were chemically ablated through local benzalkonium chloride (BAC) injection, in order to create a HD model (megacolon rats) that does not carry the possible genetic burden of HD. The animals were sacrificed either on the 20th or 25th day after ablation and were examined for histopathological changes on the wall of the small intestine, presence of bacterial translocation in body organs, body biometrics, and white blood cell count (WBC) and hemoglobin concentration. The results were compared to control animals. RESULTS: In the megacolon rats, severe damage on the small intestine as well as BT proportional to the extent of the intestinal damage and to the time elapsed after ablation was observed. Significant effects on the WBCs, hemoglobin concentration and biometric parameters were also observed. CONCLUSIONS: In megacolon rats, intestinal stasis can lead by itself to a full-blown HE. The HE lesions that promote BT are present even in regions distant from the aganglionic bowel and are proportional to the time elapsed under the influence of intestinal stasis. Systematic effects such as growth retardation are also produced.

The clinical significance of carbapenem-resistant Klebsiella pneumoniae rectal colonization in critically ill patients: from colonization to bloodstream infection.

PURPOSE: To highlight the clinical significance of carbapenem-resistant Klebsiella pneumoniae (CRKP) rectal colonization by examining the risk factors for CRKP rectal colonization and subsequent bloodstream infection (BSI) in critically ill patients. METHODOLOGY: Prospective study of CRKP rectal colonization in an intensive care unit (ICU) during a 39-month period. CRKP strains isolated from both the blood cultures and corresponding rectal specimens (n=96) of patients were screened by PCR for the presence of antibiotic resistance-associated genes. Molecular analyses were conducted to investigate the clonal relatedness of CRKP strains from the rectal and blood specimens. RESULTS: Among the 498 patients, 226 were rectally colonized by CRKP, 48 of whom developed a CRKP BSI. The median time from hospital admission to the detection of CRKP rectal colonization was 8 days, while the median time from colonization to BSI was 4 days. The duration of ICU stay, patient/nurse ratio and prior use of antianaerobic antimicrobials were associated with CRKP rectal colonization. No specific factor was associated with BSIs in the colonized patients. The blaKPC-2 gene was detected in all 96 strains, which were all classified as sequence type ST-258. Representative pairs (n=48) of CRKP strains colonizing and infecting the same patient shared the same pulsotype. CONCLUSION: Our results indicate that hospitalized patients become infected with their colonizing strains, supporting the strong association between colonization and BSI. Limiting antianaerobic antimicrobial administration, reducing the duration of ICU stay and maintaining a low patient/nurse ratio are possible strategies to restrict rectal CRKP colonization in ICUs.

Nonunion Humerous Fracture Infection Caused by Rhizobium radiobacter in a 24-Year-Old Healthy Patient: A Rare Case Report.

Although Rhizobium radiobacter is a pathogen commonly found in soil and plants, human disease caused by the Rhizobium genus is rare and cited in immunocompromised patients and in those who carry foreign plastic bodies such as catheters. We present a case of a 24-year-old woman with an adequate immune system who underwent surgery for an open fracture of the right tibia and humerus due to a car accident. One year later, she was readmitted to the hospital, due to a nonunion of the humeral fracture for surgical debridement and revision of the internal fixation with iliac crest autograft. Rhizobium radiobacter was isolated from the nonunion site, and the patient was treated with intramuscular administration of amikacin for 3 weeks followed by doxycycline per os for 8 weeks. After 3 months, the patient showed complete remission of the infection, substantial improvement, and union on the X-ray images. This is the first case of Rhizobium radiobacter infection in a patient with an adequate immune system that did not carry any foreign body and probably was initially infected due to open wound exposure to soil. Treatment of R. radiobacter infections should be individualised according to the antimicrobial susceptibility test for a successful infection management.

Low-dose hydrocortisone prolongs survival in a lethal sepsis model in adrenalectomized rats.

BACKGROUND: Controversial clinical findings of low-dose hydrocortisone supplementation in septic shock led us to investigate the impact of administration in lethal septic shock in adrenalectomized rats. MATERIALS AND METHODS: After preliminary experiments, to define the intravenous dose of hydrocortisone delivered in bilaterally adrenalectomized rats with serum cortisol level similar to sham rats, survival experiments were run in 75 rats after intraperitoneal challenge with Escherichia coli. Rats were treated with placebo, ertapenem, hydrocortisone, and a combination. Sacrifice experiments were run to measure gene transcripts in whole blood and in the liver and to assess cytokine stimulation of splenocytes and tissue overgrowth. RESULTS: The combination of hydrocortisone and ertapenem was superior to any single treatment and mandatory to achieve survival benefit. Splenocytes from infected rats had decreased production of tumor necrosis factor-alpha (TNFα); this was reversed with hydrocortisone treatment. Hydrocortisone increased the expression of TNF, Il1r2, and Hdac4 and decreased that of Dnmt3a. Bacterial burden of E. coli in kidney was decreased after hydrocortisone treatment. CONCLUSIONS: Low dose of hydrocortisone is a mandatory adjunctive to antimicrobial therapy in a rat model of septic shock after bilateral adrenalectomy. The mechanism of action is related to reversal of sepsis-induced immunosuppression through interaction with histone deacetylases and de novo DNA methyltransferases.

A Rare Case of Disseminated Pyogenic Gonococcal Infection in an Immunocompetent Woman.

We present a case of previously healthy, immunocompetent, 41-year-old woman who developed systemic inflammatory response syndrome secondary to Neisseria gonorrhoeae bacteremia. Clinical course was complicated by the simultaneous formation of multiple muscular abscesses, epidural abscess, and septic spondylodiscitis. The patient responded well to prolonged ceftriaxone treatment and was released 10 weeks after initial admission. Spinal lesions and/or pyomyositis individually constitute rare complications of disseminated gonococcal infection. This case, combining both manifestations, is to our knowledge unique. Apropos, diversity of the clinical presentation, and therapeutic challenges for this historical disease are discussed for the practicing physician.

Nationwide surveillance of resistance rates of Staphylococcus aureus clinical isolates from Greek hospitals, 2012-2013.

Purpose To evaluate the in vitro efficacy of several anti-staphylococcal agents against a nationwide collection of contemporary Staphylococcus aureus clinical isolates from several healthcare centres in Greece. Methods Thirty hospitals throughout Greece (18 in Attica) provided all clinical isolates of S.aureus from April 2012 to May 2013 to a central lab to be re-submitted to susceptibility testing. The MICs were evaluated by Vitek® 2 with the exception of ceftaroline (OXOID M.I.C. Evaluator™). Vancomycin and daptomycin MICs were also evaluated by Etest®. Heterogeneously vancomycin-intermediate strains (hVISA) were detected by the Etest® GRD. VISA phenotype was confirmed by PAP-AUC. Results A total of 1005 isolates (39% MRSA) were studied. Susceptibility rates were: erythromycin 66.5%, clindamycin 79.2%, SXT 98.9%, rifampicin 97.3%, fusidic acid 67%, moxifloxacin 78.8%, vancomycin 99.9%, ceftaroline 92.9% and linezolid, tigecycline and daptomycin 100%. For mupirocin, high level resistance could be excluded for 98.9% of isolates. Vancomycin Etest® MIC50/90 were 1.5/1.5 mg/L, 58.5% of isolates exhibited a MIC > 1 and 8.7% a MIC of 2 mg/L, while Vitek® MIC50/90 were 1/1 and 3.1% showed MIC > 1 mg/L. One VISA strain was detected. Among the selected 175 isolates that were screened for hVISA phenotype, six (3.4%) were positive. In 315 bloodstream isolates, 64.1% had a vancomycin Etest® MIC > 1 mg/L. Conclusions This multi-centre surveillance study revealed that a significant percentage of contemporary S.aureus isolates from Greek patients have a vancomycin MIC (> 1 mg/L) that may compromise the clinical efficacy of the drug for the treatment of serious infections. The in vitro activity of SXT, rifampicin, mupirocin, linezolid, tigecycline, daptomycin and ceftaroline remains excellent.

CO(2) pneumoperitoneum prolongs survival in an animal model of peritonitis compared to laparotomy.

BACKGROUND: The advantages of laparoscopic surgery have been well documented. However, the impact of pneumoperitoneum on sepsis sequelae is still equivocal. This study aimed to evaluate the effect of CO(2) pneumoperitoneum, applied under different pressures and exposure times, on sepsis cascade and mortality. MATERIAL AND METHODS: In 42 New Zealand rabbits, peritonitis was induced by the cecum ligation and puncture model. After 12 h, the animals were randomized in seven groups: a control group, four groups with pneumoperitoneum (10-15 mmHg for 60-180 min), and two groups with laparotomy (for 60 and 180 min). Blood samples were collected before cecum ligation and puncture, 12 h later and 1, 3, and 6 h after pneumoperitoneum desufflation or abdominal trauma closure to evaluate bacteremia, endotoxemia, white blood cells count, C-reactive protein, and procalcitonin levels. Furthermore, the mortality time was recorded in all animals. RESULTS: Bacteremia and endotoxemia were induced in all groups. Endotoxemia levels were significantly more elevated in the group where pneumoperitoneum was performed under 15 mmHg for 180 min compared with all other groups at 1 and 3 h after pneumoperitoneum desufflation (P < 0.05), except when compared with the group where pneumoperitoneum was performed under 10 mmHg for 180 min. White blood cell and C-reactive protein levels showed similar trends for all groups. However, serum procalcitonin reached statistically higher levels (P < 0.05) in groups with laparotomy compared with groups with pneumoperitoneum and with the control group at 6 h. Survival was lower in the laparotomy groups compared with the pneumoperitoneum groups and with the control group (P < 0.05). CONCLUSIONS: In the presence of peritonitis, CO(2) pneumoperitoneum applied in clinically standard pressures, even for extended time intervals, reduces the severity of sepsis and prolongs survival.

Functional MRI predicts memory performance after right mesiotemporal epilepsy surgery.

PURPOSE: Anterior temporal lobe resection (ATR) is a treatment option in drug-resistant epilepsy. An important risk of ATR is loss of memory because mesiotemporal structures contribute substantially to memory function. We investigated whether memory-activated functional MRI (fMRI) can predict postoperative memory loss after anterior temporal lobectomy in right-sided medial temporal lobe epilepsy (MTLE). METHODS: We included 16 patients (10 women) aged 16-54 years. The mean age at epilepsy onset was 12.5 years (range, 1-26 years). The patients' mean Wechsler IQ score was 95.2 (range, 62-125). The activation condition of fMRI consisted of retrieval from long-term memory induced by self-paced performance of an imaginative walk. All but one patient had left-sided speech dominance according to speech-activated fMRI. Outside the scanner, we evaluated the pre- and postoperative visual memory retention by using Rey Visual Design Learning Test. RESULTS: We found a correlation between the preoperative asymmetry index of memory-fMRI and the change between pre- and postsurgical measures of memory retention. Reduced activation of the mesiotemporal region ipsilateral to the epileptogenic region correlated with a favorable memory outcome after right-sided ATR. CONCLUSIONS: In light of the postoperative results, the theoretical implication of our study is that fMRI based on a simple introspective retrieval task measures memory functions. The main clinical implication of our study is that memory-fMRI might replace the invasive Wada test in MTLE by using a simple fMRI paradigm. Predictive power, however, will be studied in larger patient samples. Other studies are required for left-sided MTLE and neocortical epilepsies to assess the clinical usefulness of memory-fMRI.