Methicillin-resistant Staphylococcus aureus transmission and hospital-acquired bacteremia in a neonatal intensive care unit in Greece.

BACKGROUND: Staphylococcus aureus is a common pathogen causing hospital acquired infections (HAIs) in neonates. In this study, the epidemiology of methicillin-resistant S. aureus (MRSA) colonization and infections in a 30-bed, level III university-affiliated neonatal intensive care unit (NICU) located in a children's hospital was retrospectively investigated for the period 2014-2018. METHODS: Genes encoding Panton-Valentine Leukocidin (lukS/lukF-PV, PVL), toxic shock syndrome toxin (tst), exfoliative toxins (eta, etb), and the resistance genes mecA, mecC and fusB, were defined in 46 representative strains by PCRs. Relatedness of strains was assessed by MLST. RESULTS: Of 1538 neonates, 77 (5%) had a positive culture for MRSA (23/77 were NICU-acquired and 54/77 imported cases). Four MRSA bacteremias occurred. Most isolates were multi-resistant. One major clone was identified, ST225, among 40 tested neonatal strains (23/40, 58%). Of these, 14/23 were imported from the same maternity hospital (MH). Another clone, ST217, was predominant (4/6) among health care workers (HCWs), found colonized. Four isolates classified as ST80 were PVL-positive. Additional four strains carried tst (10%), belonging to ST30 and ST225 (two strains each), and two etb. The implicated MH was notified for the problem, decolonization treatment was successfully performed in HCWs and neonates. Strengthening of infection control measures with emphasis on hand hygiene was applied. CONCLUSIONS: Uncovering reservoirs for on-going MRSA transmission in NICUs has proved challenging. Well known nosocomial MRSA clones are being constantly introduced and transmitted via MHs and HCWs. Effective infection prevention and control requires constant vigilance.

Emergence of a mupirocin-resistant, methicillin-susceptible Staphylococcus aureus clone associated with skin and soft tissue infections in Greece.

BACKGROUND: Staphylococcus aureus causes various infections, including skin and soft tissue infections (SSTIs). In this study, methicillin-susceptible S. aureus (MSSA) from SSTIs among patients in three tertiary-care hospitals in Greece were studied in terms of antimicrobial resistance, clonal distribution, toxin and adhesin genes carriage. RESULTS: During a five-year period (2014-2018), 6145 S. aureus were recovered from 13,244 patients with SSTIs and tested for antimicrobial susceptibility. MSSA were 4806 (78.21 %) including 1484 isolates with mupirocin minimum inhibitory concentration (MIC) > 64 mg/L (30.88 %). Two hundred and sixty representative mupirocin-resistant MSSA were analyzed for genes encoding Panton-Valentine leukocidin (PVL, lukS/lukF-PV), exfoliative toxins (eta, etb), adhesin FnbA (fnbA) and resistance genes mupA (high-level resistance to mupirocin), fusB (fusidic acid), aminoglycosides' modifying enzymes, ermA, ermC and msrA (macrolides/lincosamides) by PCRs. Strains were classified into clones by PFGE and MLST. All mupirocin-resistant MSSA were penicillin-resistant; 92.7 % expressed resistance to fusidic acid and 88.9 % to tobramycin. All 260 molecularly analyzed isolates were mupA-positive; all fusidic acid-resistant (241/260) carried fusB whereas, the tobramycin-resistant ones (230), ant(4')-Ia. The majority carried eta (93.85 %), etb (98.08 %) and fnbA (88.85 %). PFGE typing revealed a mostly unvarying population; 260 MSSA were grouped into three types. One major eta/etb-positive clone comprising of 258/260 strains (99.2 %), PFGE type 1, was classified as ST121, including nine strains co-carrying PVL. Another PVL-positive strain was identified as ST1, and one toxins-negative as ST21. CONCLUSIONS: A mupirocin-resistant MSSA clone, ST121, carrying resistance, exfoliative toxins and adhesin genes, was spread and predominated in SSTIs from patients in Greece during the five-year studied period.

In vitro activity of ceftazidime/avibactam against isolates of carbapenem-non-susceptible Enterobacteriaceae collected during the INFORM global surveillance programme (2015-17).

OBJECTIVES: To report data for ceftazidime/avibactam and comparators against meropenem-non-susceptible Enterobacteriaceae collected globally (excluding centres in the USA) from 2015 to 2017 as part of the International Network For Optimal Resistance Monitoring (INFORM) surveillance programme. METHODS: MICs and susceptibility were determined using EUCAST broth microdilution methodology and EUCAST breakpoints. Isolates were screened to detect genes encoding ß-lactamases using multiplex PCR assays. MBL-positive isolates were those in which one or more of the IMP, VIM and/or NDM genes were detected. RESULTS: A total of 1460 meropenem-non-susceptible isolates were collected and, of the agents on the panel, susceptibility was highest to ceftazidime/avibactam, colistin and tigecycline [73.0%, 77.0% (1081/1403) and 78.1%, respectively]. Ceftazidime/avibactam was not active against MBL-positive isolates (n=367); these isolates showed the highest rates of susceptibility to colistin (92.1%, 303/329), tigecycline (71.9%) and amikacin (46.6%). A total of 394 isolates were resistant to ceftazidime/avibactam and, of the 369 isolates that were screened, 98.4% were found to carry a gene encoding an MBL enzyme. Among isolates that were identified as carbapenemase positive and MBL negative (n=910), susceptibility was highest to ceftazidime/avibactam (99.8%). Susceptibility was also highest to ceftazidime/avibactam among isolates that were carbapenemase negative and MBL negative (94/98, 95.9%). CONCLUSIONS: These data highlight the need for continued surveillance of antimicrobial activity as well as the need for new antimicrobials to treat infections caused by meropenem-non-susceptible Enterobacteriaceae, for which the options are extremely limited.

Molecular characteristics and predictors of mortality among Gram-positive bacteria isolated from bloodstream infections in critically ill patients during a 5-year period (2012-2016).

To identify the molecular characteristics of Gram-positive cocci isolated from blood cultures and clinical outcome among critically ill patients. This retrospective study was conducted in the general intensive care unit of the University General Hospital of Patras, Greece, during a 5-year period (2012-2016). All adult patients with a Gram-positive BSI were included. PCR was applied to identify mecA gene (staphylococci); vanA, vanB, and vanC genes (enterococci). Linezolid-resistant S. epidermidis, MRSA, and VRE were further typed by multilocus sequence typing. Mutations in region V of 23S rDNA and ribosomal protein L4were investigated by PCR and sequencing analysis. The presence of the cfr gene was tested by PCR. In total, 141 Gram-positive BSIs were included. Coagulase-negative staphylococci predominated (n = 69; 65 methicillin-resistant, 23 linezolid-resistant carrying both C2534T and T2504A mutations and belonging to the ST22 clone), followed by enterococci (n = 46; 11 vancomycin-resistant carrying vanA gene, classified into four clones), S. aureus (n = 22; 10 methicillin-resistant, classified into three clones) and streptococci (n = 4). The most common type of infection was catheter-related (66; 46.8%), followed by primary BSI (28; 19.9%). Overall 14-day fatality was 24.8%. Multivariate analysis revealed septic shock as independent predictor of fatality, while appropriate empiric antimicrobial treatment and catheter-related BSI were identified as a predictor of good prognosis. Even though most of Gram-positive cocci were multidrug-resistant, fatality rate was low, associated with catheter-related BSIs. Among CNS, LR isolates represented one-third of BSIs due to the dissemination of ST22 S. epidermidis propagated by utilization of linezolid.

Fatality of Staphylococcus aureus infections in a Greek university hospital: role of inappropriate empiric treatment, methicillin resistance, and toxin genes' presence.

The aim of the present study was to identify predictors of fatality among patients with S. aureus infections requiring hospitalization. Cases hospitalized with S. aureus infections at the University General Hospital of Patras, Greece, during a 4-year period (2013-2016) were studied. mecA, lukS/lukF-PV (Panton-Valentine leukocidin, PVL), tst (toxic shock syndrome toxin), fnbA (fibronectin-binding protein A), eta, and etb (epidermolytic toxins) genes' carriage was detected by PCR in 149 selected patients. Among 464 patients, 346 were included (118 with missing data). Primary bacteremia predominated (44.2%), followed by lower respiratory tract infections (13.6%), deep seated infections (9.8%), osteoarticular (9.5%), and catheter-related bloodstream infections (6.1%). Methicillin-resistant S. aureus (MRSA) represented 33.8% of infections and were less likely to receive appropriate empiric treatment (79.5% versus 97.4%; P < 0.001). Thirty-day fatality was 14.5%. Multivariate analysis revealed that development of septic shock, Charlson Comorbidity Index, lower respiratory tract infection, bacteremia (primary or secondary), MRSA, and CRP was significantly associated with fatality. Appropriate empiric treatment was a predictor of good prognosis. Thirty-two out of 149 S. aureus (21.5%) carried lukS/lukF-PV genes, whereas, 14 (9.4%), 133 (78.7%), four (2.7%), and one (0.7%) carried tst, fnbA, eta, and etb genes, respectively. No difference was found among toxin genes' presence and mortality. PVL was significantly more frequently found among MRSA as compared to MSSA (45.1% versus 9.2%; P < 0.001). MRSA represented one third of the infections requiring hospitalization and were independently associated with fatality, probably since were more likely to receive inappropriate antibiotic treatment as compared to MSSA.

Reversal of carbapenemase-producing Klebsiella pneumoniae epidemiology from blaKPC- to blaVIM-harbouring isolates in a Greek ICU after introduction of ceftazidime/avibactam.

OBJECTIVES: Our aim was to determine the epidemiology of bloodstream infections (BSIs) by carbapenemase-producing Klebsiella pneumoniae (CP-Kp) after the introduction of ceftazidime/avibactam in January 2018 among ICU patients. PATIENTS AND METHODS: All patients hospitalized at the ICU of the University General Hospital of Patras, Greece with CP-Kp BSI during 2015-18 were included. MICs of meropenem, fosfomycin, tigecycline and ceftazidime/avibactam (only for isolates from 2018) were determined by Etest, whereas for colistin, the broth microdilution method was applied. All isolates were tested by PCR for the presence of blaKPC, blaVIM, blaNDM and blaOXA-48 genes. RESULTS: Among 170 BSIs due to CP-Kp (2015-18), 132 (78%) were caused by isolates carrying blaKPC (4 ceftazidime/avibactam-resistant), 17 blaVIM (10%), 16 blaNDM (9%) and 5 carrying both blaKPC and blaVIM (3%). From 2015 to 2017 (125 BSIs), KPC-producing strains (110; 88%) predominated, followed by NDM-producing strains (15; 12%), whereas no VIM-producing strain was isolated. Among the 45 BSIs in 2018, 22 (49%) were due to isolates carrying blaKPC (4 ceftazidime/avibactam resistant), followed by 17 (38%) carrying blaVIM, 5 (11%) carrying both blaKPC and blaVIM, and 1 isolate carrying blaNDM (2%). MBLs were more frequent in 2018 compared with 2015-17 (51% versus 12%; P < 0.001). Multivariate analysis found that prior administration of ceftazidime/avibactam (P = 0.014; OR 16.7, 95% CI 1.8-158.6) was independently associated with the development of BSI due to ceftazidime/avibactam-resistant isolates. CONCLUSIONS: Widespread ceftazidime/avibactam use may lead to a change in the palette of carbapenemases by replacing KPC with MBL-producing isolates.

Increasing incidence of candidaemia and shifting epidemiology in favor of Candida non-albicans in a 9-year period (2009-2017) in a university Greek hospital.

PURPOSE: The aim of the present study was to analyze candidaemia's epidemiology (incidence, species distribution, and susceptibility rates) and antifungal consumption during a 9-year period. METHODS: All candidaemias recorded at The University General Hospital of Patras, Greece, between 2009 and 2017 were included. Candida isolates were identified using the germ tube test, API 20C AUX System, and/or Vitek-2 YST card. Antifungal susceptibility was determined by the gradient method according to CLSI. RESULTS: During the study period, 505 episodes of candidaemia were observed with an overall incidence of 1.5 episodes per 1000 hospital admissions (1.1 episodes in 2009 to 1.9 in 2017: P 0.038, r 0.694). C. albicans was the leading cause (200 cases; 39.6%), followed by C. parapsilosis (185; 36.6%), C. glabrata (56; 11.1%), C. tropicalis (50; 9.9%), C. krusei (8; 0.2%), C. lusitaniae (5; < 0.1%), and C. guilliermondii (1; < 0.1%). Overall resistance to fluconazole, voriconazole, anidulafungin, caspofungin, and micafungin (according to CLSI) were 11.6%, 4.1%, 2.0%, 6.0%, and 0.8%, respectively. The overall consumption of antifungal drugs was stable, with a significant reduction of fluconazole's use in favor of echinocandins. CONCLUSIONS: An increase in the incidence of candidaemia and a predominance of Candida non-albicans due to decreasing use of fluconazole in favor of more potent antifungals, such as echinocandins, are reported in this study.

European external quality assessments for identification, molecular typing and characterization of Staphylococcus aureus.

Objectives: We present the results of two European external quality assessments (EQAs) conducted in 2014 and 2016 under the auspices of the Study Group on Staphylococci and Staphylococcal Infections of ESCMID. The objective was to assess the performance of participating centres in characterizing Staphylococcus aureus using their standard in-house phenotypic and genotypic protocols. Methods: A total of 11 well-characterized blindly coded S. aureus (n = 9), Staphylococcus argenteus (n = 1) and Staphylococcus capitis (n = 1) strains were distributed to participants for analysis. Species identification, MIC determination, antimicrobial susceptibility testing, antimicrobial resistance and toxin gene detection and molecular typing including spa typing, SCCmec typing and MLST were performed. Results: Thirteen laboratories from 12 European countries participated in one EQA or both EQAs. Despite considerable diversity in the methods employed, good concordance (90%-100%) with expected results was obtained. Discrepancies were observed for: (i) identification of the S. argenteus strain; (ii) phenotypic detection of low-level resistance to oxacillin in the mecC-positive strain; (iii) phenotypic detection of the inducible MLSB strain; and (iv) WGS-based detection of some resistance and toxin genes. Conclusions: Overall, good concordance (90%-100%) with expected results was observed. In some instances, the accurate detection of resistance and toxin genes from WGS data proved problematic, highlighting the need for validated and internationally agreed-on bioinformatics pipelines before such techniques are implemented routinely by microbiology laboratories. We strongly recommend all national reference laboratories and laboratories acting as referral centres to participate in such EQA initiatives.

Expression of α-Defensins, CD20+ B-lymphocytes, and Intraepithelial CD3+ T-lymphocytes in the Intestinal Mucosa of Patients with Liver Cirrhosis: Emerging Mediators of Intestinal Barrier Function.

AIM: The present study investigates the role of innate and adaptive immune system of intestinal mucosal barrier function in cirrhosis. METHODS: Forty patients with decompensated (n = 40, group A), 27 with compensated cirrhosis (n = 27, group B), and 27 controls (n = 27, group C) were subjected to duodenal biopsy. Expression of α-defensins 5 and 6 at the intestinal crypts was evaluated by immunohistochemistry and immunofluorescence. Serum endotoxin, intestinal T-intraepithelial, and lamina propria B-lymphocytes were quantified. RESULTS: Cirrhotic patients presented higher endotoxin concentrations (p < 0.0001) and diminished HD5 and HD6 expression compared to healthy controls (p = 0.000287, p = 0.000314, respectively). The diminished HD5 and HD6 expressions were also apparent among the decompensated patients compared to compensated group (p = 0.025, p = 0.041, respectively). HD5 and HD6 expressions were correlated with endotoxin levels (r = -0.790, p < 0.0001, r = - 0.777, p < 0.0001, respectively). Although intraepithelial T-lymphocytes were decreased in group A compared to group C (p = 0.002), no notable alterations between groups B and C were observed. The B-lymphocytic infiltrate did not differ among the investigated groups. CONCLUSIONS: These data demonstrate that decreased expression of antimicrobial peptides may be considered as a potential pathophysiological mechanism of intestinal barrier dysfunction in liver cirrhosis, while remodeling of gut-associated lymphoid tissue as an acquired immune response to bio-pathogens remains an open field to illuminate.

Emergence of a Staphylococcus aureus Clone Resistant to Mupirocin and Fusidic Acid Carrying Exotoxin Genes and Causing Mainly Skin Infections.

Skin and soft tissue infections (SSTIs) caused by mupirocin-resistant Staphylococcus aureus strains have recently increased in number in our settings. We sought to evaluate the characteristics of these cases over a 43-month period. Data for all community-acquired staphylococcal infections caused by mupirocin-resistant strains were retrospectively reviewed. Genes encoding products producing high-level resistance (HLR) to mupirocin (mupA), fusidic acid resistance (fusB), resistance to macrolides and lincosamides (ermC and ermA), Panton-Valentine leukocidin (PVL) (lukS/lukF-PV), exfoliative toxins (eta and etb), and fibronectin binding protein A (fnbA) were investigated by PCRs in 102 selected preserved strains. Genotyping was performed by SCCmec and agr typing, whereas clonality was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). A total of 437 cases among 2,137 staphylococcal infections were recorded in 2013 to 2016; they were all SSTIs with the exception of 1 case of primary bacteremia. Impetigo was the predominant clinical entity (371 cases [84.9%]), followed by staphylococcal scalded skin syndrome (21 cases [4.8%]), and there were no abscesses. The number of infections detected annually increased during the study years. All except 3 isolates were methicillin susceptible. The rates of HLR to mupirocin and constitutive resistance to clindamycin were 99% and 20.1%, respectively. Among the 102 tested strains, 100 (98%) were mupA positive and 97 (95%) were fusB positive, 26/27 clindamycin-resistant strains (96.3%) were ermA positive, 83 strains (81.4%) were lukS/lukF positive, 95 (93%) carried both eta and etb genes, and 99 (97%) were fnbA positive. Genotyping of methicillin-sensitive S. aureus (MSSA) strains revealed that 96/99 (96.7%) belonged to one main pulsotype, pulsotype 1, classified as sequence type 121 (ST121). The emergence of a single MSSA clone (ST121) causing impetigo was documented. Resistance to topical antimicrobials and a rich toxinogenic profile confer to this clone adaptability for spread in the community.

Risk factors and predictors of mortality of candidaemia among critically ill patients: role of antifungal prophylaxis in its development and in selection of non-albicans species.

PURPOSE: The aim of the present study is to identify risk factors for development and predictors of mortality of candidaemia among critically ill patients. METHODS: A 1:7 case-control study was conducted during a 4-year period (2012-2015) in a Greek Intensive Care Unit (ICU). Candidaemia was confirmed by positive blood cultures. All yeasts were identified using API 20C AUX System or Vitek 2 Advanced Expert System. Epidemiologic data were collected from the ICU computerized database and patients' chart reviews. RESULTS: Fifty-three patients developed candidaemia with non-albicans species being the predominant ones (33 patients, 62.3%). Multivariate analysis found that prior emergency surgery, malignancy, hospitalization during summer months, prior septic shock by KPC-producing Klebsiella pneumoniae and number of antibiotics administered were independently associated with candidaemia, while, prior administration of azole was a protective factor. Non-albicans candidaemia was associated with number of antibiotics administered and prior administration of echinocandin. Mortality of 14 days was 28.3% (15 patients) and was associated with SOFA score upon infection onset and septic shock, while, appropriate empirical antifungal treatment was associated with better survival. CONCLUSIONS: Prophylactic azole administration prevents development of candidaemia, while, echinocandin administration predisposes to non-albicans candidaemia. Empirical administration of an appropriate antifungal agent is associated with better survival.

Early KPC-Producing Klebsiella pneumoniae Bacteremia among Intensive Care Unit Patients Non-Colonized upon Admission.

Among 140 patients colonized by KPC-producing Klebsiella pneumoniae (KPC-Kp) between fourth and seventh day of Intensive Care Unit stay, 24 developed bacteraemia immediately after colonization. Colistin-resistance of the colonizing isolate was the factor significantly associated with early KPC-Kp bacteraemia (P < 0.001; OR 6.6, 95% CI 2.4-18.4), a worrisome finding since infections by colistin-resistant isolates is associated with increased mortality due to limited remaining therapeutic options.

Trends of Bloodstream Infections in a University Greek Hospital during a Three-Year Period: Incidence of Multidrug-Resistant Bacteria and Seasonality in Gram-negative Predominance.

The aim of the study was to assess the epidemiology, the incidence of multidrug-resistant bacteria and bloodstream infections' (BSIs) seasonality in a university hospital. This retrospective study was carried out in the University General Hospital of Patras, Greece, during 2011-13 y. Blood cultures from patients with clinical presentation suggestive of bloodstream infection were performed by the BacT/ALERT System. Isolates were identified by Vitek 2 Advanced Expert System. Antibiotic susceptibility testing was performed by the disk diffusion method and E-test. Resistance genes (mecA in staphylococci; vanA/vanB/vanC in enterococci; blaKPC/blaVIM/blaNDM in Klebsiella spp.) were detected by PCR. In total, 4607 (9.7%) blood cultures were positive from 47451 sets sent to Department of Microbiology, representing 1732 BSIs. Gram-negative bacteria (52.3%) were the most commonly isolated, followed by Gram-positive (39.5%), fungi (6.6%) and anaerobes bacteria (1.8%). The highest contamination rate was observed among Gram-positive bacteria (42.3%). Among 330 CNS and 150 Staphylococcus aureus, 281 (85.2%) and 60 (40.0%) were mecA-positive, respectively. From 113 enterococci, eight were vanA, two vanB and two vanC-positives. Of the total 207 carbapenem-resistant Klebsiella pneumoniae (73.4%), 202 carried blaKPC, four blaKPC and blaVIM and one blaVIM. A significant increase in monthly BSIs' incidence was shown (R2: 0.449), which may be attributed to a rise of Gram-positive BSIs (R2: 0.337). Gram-positive BSIs were less frequent in spring (P < 0.001), summer (P < 0.001), and autumn (P < 0.001), as compared to winter months, while Gram-negative bacteria (P < 0.001) and fungi (P < 0.001) were more frequent in summer months. BSIs due to methicillin resistant S. aureus and carbapenem-resistant Gram-negative bacteria increased during the study period. The increasing incidence of BSIs can be attributed to an increase of Gram-positive BSI incidence, even though Gram-negative bacteria remained the predominant ones. Seasonality may play a role in the predominance of Gram-negative's BSI.

Daptomycin Liposomes Exhibit Enhanced Activity against Staphylococci Biofilms Compared to Free Drug.

The purpose of the present study was to investigate the anti-staphylococcal activity of liposomal daptomycin against four biofilm-producing S. aureus and S. epidermidis clinical strains, three of which are methicillin-resistant. Neutral and negatively charged daptomycin-loaded liposomes were prepared using three methods, namely, thin-film hydration (TFH), a dehydration-rehydration vesicle (DRV) method, and microfluidic mixing (MM); moreover, they were characterized for drug encapsulation (EE%), size distribution, zeta-potential, vesicle stability, drug release, and drug integrity. Interestingly, whilst drug loading in THF and DRV nanosized (by extrusion) vesicles was around 30-35, very low loading (~4%) was possible in MM vesicles, requiring further explanatory investigations. Liposomal encapsulation protected daptomycin from degradation and preserved its bioactivity. Biofilm mass (crystal violet, CV), biofilm viability (MTT), and growth curve (GC) assays evaluated the antimicrobial activity of neutral and negatively charged daptomycin-liposomes towards planktonic bacteria and biofilms. Neutral liposomes exhibited dramatically enhanced inhibition of bacterial growth (compared to the free drug) for all species studied, while negatively charged liposomes were totally inactive. Biofilm prevention and treatment studies revealed high antibiofilm activity of liposomal daptomycin. Neutral liposomes were more active for prevention and negative charge ones for treating established biofilms. Planktonic bacteria as well as the matured biofilms of low daptomycin-susceptible, methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE) strains were almost completely eradicated by liposomal-daptomycin, indicating the need for their further exploration as antimicrobial therapeutics.

Spread of multidrug-resistant Pseudomonas aeruginosa clones in a university hospital.

An outbreak of multidrug-resistant Pseudomonas aeruginosa (MDRPA) infections in a university hospital is described. Phenotypic and genotypic analysis of 240 isolates revealed that 152 patients, mainly in the intensive care unit (ICU), were colonized or infected with MDRPA, the majority with O11. All metallo-ß-lactamase (MBL)-positive isolates carried the bla(VIM-2) or bla(VIM-1) gene. One or more type III secretion system toxin genes were detected in most isolates. Five dominant pulsed-field gel electrophoresis (PFGE) types were characterized, associated with ST235, ST111, ST253, ST309, and ST639.

Factors influencing linezolid-nonsusceptible coagulase-negative staphylococci dissemination among patients in the intensive care unit: a retrospective cohort study.

BACKGROUND: The aim of the present study was to identify risk factors for linezolid-nonsusceptible coagulase-negative staphylococci (CNS) dissemination in the intensive care unit. METHODS: Among the 246 patients included, 33 revealed a linezolid-nonsusceptible CNS-positive culture specimen, 68 were positive for linezolid-susceptible CNS and 145 served as controls. Isolates were characterized by phenotypic and genotypic methods to species level, susceptibility to antistaphylococcal agents and clones. RESULTS: Among the 33 linezolid-nonsusceptible CNS patients, 29 revealed Staphylococcus epidermidis and 4 Staphylococcus capitis. All S. epidermidis strains belonged to the ST22 clone (by multilocus sequence typing), 26 carried both C2534T and T2504A and 3 strains were C2543T mutations. S. capitis strains were stratified as a common pulsed-field gel electrophoresis type and carried the G2576T mutation. Risk factors for linezolid-nonsusceptible CNS isolation were linezolid administration and mean number of linezolid-nonsusceptible CNS-positive patients in nearby beds per day. CONCLUSIONS: These results reinforce the aspect of rational antibiotic usage, but also highlight the need for strict infection control measures to prevent the dissemination of linezolid-nonsusceptible CNS.

Altered intestinal tight junctions' expression in patients with liver cirrhosis: a pathogenetic mechanism of intestinal hyperpermeability.

BACKGROUND: Increased intestinal permeability in cirrhosis exerts a pivotal role in the pathogenesis of spontaneous bacterial peritonitis and other complications of cirrhosis through promotion of systemic endotoxemia. This study was designed to investigate whether the expression of tight junction (TJ) proteins, which regulate gut paracellular permeability, is altered in the intestinal mucosa of patients with liver cirrhosis and study its potential association with the stage of liver disease and the development of systemic endotoxemia. DESIGN: Twenty-four patients with cirrhosis at a decompensated (n = 12, group A) or compensated condition (n = 12, group B) and 12 healthy controls (group C) were subjected to duodenal biopsy. The expression of the TJ proteins occludin and claudin-1 in the intestinal epithelium was evaluated by immunohistochemistry. Plasma endotoxin concentrations were also determined. RESULTS: Patients with cirrhosis presented significantly higher serum endotoxin concentrations as compared to healthy controls (P < 0·001), whilst endotoxemia was higher in decompensated disease (P < 0·05 vs. compensated cirrhosis). Patients with decompensated and compensated cirrhosis presented significantly reduced expression of occludin and claudin-1 as compared to controls (P < 0·01, respectively). These alterations were significantly more pronounced in decompensated patients as compared to compensated (P < 0·05). Regarding occludin, in patients with cirrhosis, a specific pattern of expression in the intestinal epithelium was observed, with a gradually increasing loss of expression from crypt to tip of the villi. Occludin and claudin-1 expression were inversely correlated with Child-Pugh score (P < 0·001), the grade of oesophageal varices (P < 0·01) and endotoxin concentrations (P < 0·001). CONCLUSIONS: This study demonstrates for the first time that human liver cirrhosis induces significant alterations in enterocytes' TJs. These changes might represent an important cellular mechanism for intestinal barrier dysfunction and hyperpermeability in patients with liver cirrhosis.

Predominance of community-associated, methicillin-susceptible Staphylococcus aureus infections among hospitalized children and adolescents.

Introduction. Staphylococcus aureus infections cause significant morbidity and mortality in children and adolescents.Gap Statement. There is limited data on the characteristics of S. aureus infections requiring hospitalization in childhood.Aim.To investigate the molecular epidemiology and antibiotic resistance of S. aureus clinical isolates from children and adolescents.Methodology.All S. aureus isolates recovered from patients aged <18 years, admitted to a referral hospital, with culture-proven invasive or non-invasive infections during the 4 year period 2015 to 2018 were analysed for antimicrobial resistance, virulence genes, PFGE and multilocus sequence typing (MLST). Cases were assigned to community-associated, community-onset healthcare-associated or hospital-associated infections based on epidemiological case definitions.Results.Among 139 S. aureus infections, 88.5 % (123/139) were caused by methicillin-susceptible isolates (MSSA) and 73.4 % (102/139) were classified as community-associated infections. tst and lukS/lukF-PV genes were more common among MRSA as compared to MSSA isolates (tst, p 0.04; lukS/lukF-PV, p 0.007). Invasive disease was noted in 22/139 patients (15.8 %). Staphylococcal scalded skin syndrome caused by fusidic-resistant MSSA increased over time (22.8 % in 2017-2018 vs 8.3 % in 2015-2016, OR 3.24; 95 % CI 1.10-8.36; P 0.03). By PFGE genotyping, 22 pulsotypes were identified. A total of five sequence types (STs) were identified among 58 isolates analysed by MLST. More than one third of MSSA isolates (40/123, 32.5 %) and 13/23 (56.5 %) of SSSS isolates belonged to pulsotype 1, classified as sequence type 121 (ST121). MRSA isolates were equally distributed to pulsotypes A (ST30), B (ST239), C (ST80), H (ST225). ST121 isolates carried fnbA (40/40), eta/etb genes (29/40), exhibited high resistance to fusidic acid and were increasingly resistant to mupirocin.Conclusion.In our population, community-associated MSSA was the predominant cause of S. aureus infections characterized by polyclonality, increasing resistance to fusidic acid and mupirocin. PFGE type 1 ST121 clone, harboured exfoliative toxin genes and was associated with rising trends of SSSS.

Clonal dissemination and resistance genes among Stenotrophomonas maltophilia in a Greek University Hospital during a four-year period.

Treatment of Stenotrophomonas maltophilia infections comprises of sulfamethoxazole/tripethoprim (SXT) or fluoroquinolones. We investigated antimicrobial resistance, presence of resistance genes (sul1, smqnr) and clonal dissemination in S. maltophilia from a university hospital. Among 62 isolates, 45 (73%) represented infection. Two isolates (3%) were resistant to SXT and three (5%) to levofloxacin. Twenty-nine isolates (47%), including two out of three levofloxacin-resistant, carried smqnr. Resistance of S. maltophilia was low and was not associated with sul1 or smqnr carriage. Although high degree of genetic diversity was identified (29 pulsotypes), 22/62 (35.5%) strains were classified into four clones; clone b was associated with bacteraemias.

Persistent Coagulase-Negative Staphylococcal Bacteremia in Neonates: Clinical, Microbiological Characteristics and Changes within a Decade.

Atypical outbreaks of persistent coagulase-negative staphylococci (CoNS) bacteremias, defined as three or more consecutive positive blood cultures with the same CoNS species, at least 48 h apart, have been reported in neonatal intensive-care units (NICUs). Our aim was to describe the profile of these cases in our NICU over a two-year period with the objective of assessing possible changes within a decade. Demographics, clinical and microbiological data were recorded for all CoNS bacteremias in our tertiary NICU during 2016-2017 and compared with the results of the same study in 2006-2007. Fifty-six cases of CoNS sepsis were recorded. Fourteen (25%) of them were persistent. There were no significant differences in demographic and clinical characteristics between cases with persistent vs. non-persistent bacteremia. Staphylococcus epidermidis was the most common species. In logistic regression analysis, biofilm production (ß = 2.464, p = 0.04) was the most significant determinant for the development of persistent CoNS bacteremia. Our isolates were less likely to produce biofilm and carry ica operon as compared to those of 2006-2007. The cases of persistent CoNS sepsis have decreased within a decade, which could be attributed to the implementation of intensive infection control practices. Biofilm production remains the most important risk factor.