The efficacy of a non-leaching antibacterial central venous catheter - a prospective, randomized, double-blind study.

BACKGROUND: Antimicrobial coatings of central venous catheters (CVC) have the potential to reduce the risk of infectious complications. The aim of this study was to examine the efficacy of a catheter with a non-leaching antimicrobial coating against catheter colonization and bloodstream infections (BSI). METHODS: The study was conducted in two centers using a prospective, randomized, double-blind and controlled design (680 intensive care patients; a protective CVC (Certofix® protect) or a standard CVC (Certofix®). Primary objectives were the rates of catheter colonization and BSI in the two groups. Other baseline demographics, APACHE II score, insertion site, location of CVC placement (ICU or theatre), indwelling time and length of ICU stay were comparable for both groups. RESULTS: While the rate of catheter colonization between the coated and uncoated CVC (17.4% vs. 18.7%, P=0.7477) and the rate of microbiologically confirmed catheter associated infections were similar (1.4% vs. 1.9%, P=0.7521), the coated CVC showed a significantly lower incidence of BSI (2.0% vs. 6.5%, P=0.0081) and a significantly lower mean incidence of BSI per 1000 catheter days (3.2 vs. 8.3, P=0.0356). CONCLUSION: The non-leaching antibacterial coating of the protective catheter was effective in reducing the incidence of BSI but not the rate of catheter colonization. However, the incidence of BSI is a better surrogate marker for the risk of developing clinical signs of infection suggesting that use of the non-leaching protective catheter is effective in this regard. Trial number: ClinicalTrials.gov (ID: NCT00555282), https://clinicaltrials.gov/show/NCT00555282.

Escherichia coli isolates from patients with inflammatory bowel disease: ExPEC virulence- and colicin-determinants are more frequent compared to healthy controls.

A set of 178 Escherichia coli isolates taken from patients with inflammatory bowel disease (IBD) was analyzed for bacteriocin production and tested for the prevalence of 30 bacteriocin and 22 virulence factor determinants. Additionally, E. coli phylogenetic groups were also determined. Pulsed-field gel electrophoresis (PFGE) was used for exclusion of clonal character of isolates. Results were compared to data from a previously published analysis of 1283 fecal commensal E. coli isolates. The frequency of bacteriocinogenic isolates (66.9%) was significantly higher in IBD E. coli compared to fecal commensal E. coli isolates (54.2%, p < 0.01). In the group of IBD E. coli isolates, a higher prevalence of determinants for group B colicins (i.e., colicins B, D, Ia, Ib, M, and 5/10) (p < 0.01), including a higher prevalence of the colicin B determinant (p < 0.01) was found. Virulence factor determinants encoding fimbriae (fimA, 91.0%; pap, 27.5%), cytotoxic necrotizing factor (cnf1, 11.2%), aerobactin synthesis (aer, 43.3%), and the locus associated with invasivity (ial, 9.0%) were more prevalent in IBD E. coli (p < 0.05 for all five determinants). E. coli isolates from IBD mucosal biopsies were more frequently bacteriocinogenic (84.6%, p < 0.01) compared to fecal IBD isolates and fecal commensal E. coli. PFGE analysis revealed clusters specific for IBD E. coli isolates (n = 11), for fecal isolates (n = 13), and clusters containing both IBD and fecal isolates (n = 10). ExPEC (Extraintestinal Pathogenic E. coli) virulence and colicin determinants appear to be important characteristics of IBD E. coli isolates, especially the E. coli isolates obtained directly from biopsy samples.

Human Escherichia coli isolates from hemocultures: Septicemia linked to urogenital tract infections is caused by isolates harboring more virulence genes than bacteraemia linked to other conditions.

Escherichia coli is the most common cause of bloodstream infections and community-acquired sepsis. The main aim of this study was to determine virulence characteristics of E. coli isolates from hemocultures of patients with a primary disease of urogenital tract, digestive system, a neoplastic blood disease, or other conditions. Results from a set of 314 E. coli isolates from hemocultures were compared to data from a previously published analysis of 1283 fecal commensal E. coli isolates. Genetic profiling of the 314 E. coli isolates involved determination of phylogenetic group (A, B1, B2, D, C, E, and F), identification of 21 virulence factors, as well as 30 bacteriocin-encoding determinants. Pulsed-field gel electrophoresis was used to analyze clonal character of the hemoculture-derived isolates. The E. coli isolates from hemocultures belonged mainly to phylogenetic groups B2 (59.9%) and D (21.0%), and less frequently to phylogroups A (10.2%) and B1 (5.7%). Commonly detected virulence factors included adhesins (fimA 92.0%, pap 47.1%, and sfa 26.8%), and iron-uptake encoding genes (fyuA 87.9%, fepC 79.6%, aer 70.7%, iucC 68.2%, and ireA 13.7%), followed by colibactin (pks island 31.5%), and cytotoxic necrotizing factor (cnf1 11.1%). A higher frequency of microcin producers (and microcin M determinant) and a lower frequency of colicin Ib and microcin B17 was found in hemoculture-derived isolates compared to commensal fecal isolates. E. coli isolates from hemocultures harbored more virulence genes compared to fecal E. coli isolates. In addition, hemoculture E. coli isolates from patients with primary diagnosis related to urogenital tract were clearly different and more virulence genes were detected in these isolates compared to both fecal isolates and hemoculture-derived isolates from patients with blood and gastrointestinal diseases.

Human extraintestinal pathogenic Escherichia coli strains differ in prevalence of virulence factors, phylogroups, and bacteriocin determinants.

BACKGROUND: The study used a set of 407 human extraintestinal pathogenic E. coli strains (ExPEC) isolated from (1) skin and soft tissue infections, (2) respiratory infections, (3) intra-abdominal infections, and (4) genital smears. The set was tested for bacteriocin production, for prevalence of bacteriocin and virulence determinants, and for phylogenetic typing. Results obtained from the group of ExPEC strains were compared to data from our previously published analyses of 1283 fecal commensal E. coli strains. RESULTS: The frequency of bacteriocinogeny was significantly higher in the set of ExPEC strains (63.1 %), compared to fecal E. coli (54.2 %; p < 0.01). Microcin producers and microcin determinants dominated in ExPEC strains, while colicin producers and colicin determinants were more frequent in fecal E. coli (p < 0.01). Higher production of microcin M and lower production of microcin B17, colicin Ib, and Js was detected in the set of ExPEC strains. ExPEC strains had a significantly higher prevalence of phylogenetic group B2 (52.6 %) compared to fecal E. coli strains (38.3 %; p < 0.01). CONCLUSIONS: Human ExPEC strains were shown to differ from human fecal strains in a number of parameters including bacteriocin production, prevalence of several bacteriocin and virulence determinants, and prevalence of phylogenetic groups. Differences in these parameters were also identified within subgroups of ExPEC strains of diverse origin. While some microcin determinants (mM, mH47) were associated with virulent strains, other bacteriocin types (mB17, Ib, and Js) were associated with fecal flora.

Epidemiology of hospital-acquired pneumonia: Results of a Central European multicenter, prospective, observational study compared with data from the European region.

BACKGROUND: Hospital-acquired pneumonia (HAP) is associated with high mortality. In Central Europe, there is a dearth of information on the prevalence and treatment of HAP. This project was aimed at collecting multicenter epidemiological data on patients with HAP in the Czech Republic and comparing them with supraregional data. METHODS: This prospective, multicenter, observational study processed data from a database supported by a Czech Ministry of Health grant project. Included were all consecutive patients aged 18 and over who were admitted to participating intensive care units (ICUs) between 1 May 2013 and 31 December 2014 and met the inclusion criterion of having HAP. The primary endpoint was to analyze the relationships between 30-day mortality (during the stay in or after discharge from ICUs) and the microbiological etiological agent and adequacy of initial empirical antibiotic therapy in HAP patients. RESULTS: The group dataset contained data on 330 enrolled patients. The final validated dataset involved 214 patients, 168 males (78.5%) and 46 females (21.5%), from whom 278 valid lower airway samples were obtained. The mean patient age was 59.9 years. The mean APACHE II score at admission was 21. Community-acquired pneumonia was identified in 13 patients and HAP in 201 patients, of whom 26 (12.1%) had early-onset and 175 (81.8%) had late-onset HAP. Twenty-two bacterial species were identified as etiologic agents but only six of them exceeded a frequency of detection of 5% (Klebsiella pneumoniae 20.4%, Pseudomonas aeruginosa 20.0%, Escherichia coli 10.8%, Enterobacter spp. 8.1%, Staphylococcus aureus 6.2% and Burkholderia cepacia complex 5.8%). Patients infected with Staphylococcus aureus had significantly higher rates of early-onset HAP than those with other etiologic agents. The overall 30-day mortality rate for HAP was 29.9%, with 19.2% mortality for early-onset HAP and 31.4% mortality for late-onset HAP. Patients with late-onset HAP receiving adequate initial empirical antibiotic therapy had statistically significantly lower 30-day mortality than those receiving inadequate initial antibiotic therapy (23.8% vs 42.9%). Patients with ventilator-associated pneumonia (VAP) had significantly higher mortality than those who developed HAP with no association with mechanical ventilation (34.6% vs 12.7%). Patients having VAP treated with adequate initial antibiotic therapy had lower 30-day mortality than those receiving inadequate therapy (27.2% vs 44.8%). CONCLUSIONS: The present study was the first to collect multicenter data on the epidemiology of HAP in the Central European Region, with respect to the incidence of etiologic agents causing HAP. It was concerned with relationships between 30-day patient mortality and the type of HAP, etiologic agent and adequacy of initial empirical antibiotic therapy.

Microcin determinants are associated with B2 phylogroup of human fecal Escherichia coli isolates.

Escherichia coli strains are classified into four main phylogenetic groups (A, B1, B2, and D) and strains of these phylogroups differ in a number of characteristics. This study tested whether human fecal E. coli isolates belonging to different phylogroups differ in prevalence of bacteriocinogenic isolates and prevalence of individual bacteriocinogenic determinants. A set of 1283 fecal E. coli isolates from patients with different diseases was tested for the presence of DNA regions allowing classification into E. coli phylogroups and for the ability to produce bacteriocins (23 colicins and 7 microcins). Of the isolates tested, the most common was phylogroup B2 (38.3%) followed by phylogroups A (28.3%), D (26.3%) and B1 (7.2%). Altogether, 695 bacteriocin producers were identified representing 54.2% of all tested isolates. The highest prevalence of bacteriocin producers was found in group B2 (60.3%) and the lowest in group B1 (44.6%). Determinants encoding colicins E1, Ia, and microcin mV were most common in phylogroup A, determinants encoding microcins mM and mH47 were most common in phylogroup B2, and determinant encoding mB17 was most common in phylogroup D. The highest prevalence of bacteriocinogeny was found in phylogroup B2, suggesting that bacteriocinogeny and especially the synthesis of microcins was associated with virulent and resident E. coli strains.

Determinants encoding fimbriae type 1 in fecal Escherichia coli are associated with increased frequency of bacteriocinogeny.

BACKGROUND: To screen whether E. coli strains encoding type 1 fimbriae, isolated from fecal microflora, produce bacteriocins more often relative to fimA-negative E. coli strains of similar origin. METHODS: PCR assays were used to detect presence of genes encoding 30 bacteriocin determinants (23 colicin- and 7 microcin-encoding genes) and 18 virulence determinants in 579 E. coli strains of human and animal origin isolated from hospitals and animal facilities in the Czech and Slovak Republic. E. coli strains were also classified into phylogroups (A, B1, B2 and D). RESULTS: fimA-negative E. coli strains (defined as those possessing none of the 18 tested virulence determinants) were compared to fimA-positive E. coli strains (possessing fimA as the only detected virulence determinant). Strains with identified bacteriocin genes were more commonly found among fimA-positive E. coli strains (35.6%) compared to fimA-negative E. coli strains (21.9%, p<0.01) and this was true for both colicin and microcin determinants (p=0.02 and p<0.01, respectively). In addition, an increased number of strains encoding colicin E1 were found among fimA-positive E. coli strains (p<0.01). CONCLUSIONS: fimA-positive E. coli strains produced bacteriocins (colicins and microcins) more often compared to fimA-negative strains of similar origin. Since type 1 fimbriae of E. coli have been shown to mediate adhesion to epithelial host cells and help colonize the intestines, bacteriocin synthesis appears to be an additional feature of colonizing E. coli strains.

Bacteriocin-encoding genes and ExPEC virulence determinants are associated in human fecal Escherichia coli strains.

BACKGROUND: A set of 1181 E. coli strains of human fecal origin isolated in the South Moravia region of the Czech Republic was collected during the years 2007-2010. Altogether, 17 virulence determinants and 31 bacteriocin-encoding genes were tested in each of them. RESULTS: The occurrence of bacteriocin-encoding genes was found to be positively correlated with the occurrence of E. coli virulence factors. Based on the presence of virulence factors and their combinations, E. coli strains were classified as non-pathogenic E. coli (n = 399), diarrhea-associated E. coli (n = 179) and ExPEC strains (n = 603). Non-pathogenic and diarrhea-associated E. coli strains had a low frequency of bacteriocinogeny (32.6% and 36.9%, respectively). ExPEC strains encoding S-fimbriae (sfa), P-fimbriae (pap) and having genes for aerobactin biosynthesis (aer, iucC), α-hemolysis (α-hly) and cytotoxic necrosis factor (cnf1) were often bacteriocinogenic (73.8%), had a high prevalence of bacteriocin multi-producers and showed a higher frequency of genes encoding microcins H47, M, V, B17 and colicins E1, Ia and S4. CONCLUSIONS: The occurrence of bacteriocin-encoding genes and ExPEC virulence determinants correlate positively in E. coli strains of human fecal origin. Bacteriocin synthesis appears to modulate the ability of E. coli strains to reside in the human intestine and/or the virulence of the corresponding strains.

Unique activity spectrum of colicin FY: all 110 characterized Yersinia enterocolitica isolates were colicin FY susceptible.

Colicin FY is a plasmid encoded toxin that recognizes a yersinia-specific outer membrane protein (YiuR) as a receptor molecule. We have previously shown that the activity spectrum of colicin FY comprises strains of the genus Yersinia. In this study, we analyzed the activity of colicin FY against 110 Yersinia enterocolitica isolates differing in geographical origin and source. All isolates were characterized through analysis of 16S rRNA genes, serotyping, biotyping, restriction profiling of genomic DNA, detection of virulence markers and susceptibility to antibiotics. This confirmed the broad variability of the collection, in which all 110 Y. enterocolitica isolates, representing 77 various strains, were inhibited by colicin FY. Although isolates showed variable levels of susceptibility to colicin FY, it was not associated with any strain characteristic. The universal susceptibility of Y. enterocolitica strains to colicin FY together with the absence of activity towards strains outside the Yersinia genus suggests potential therapeutic applications for colicin FY.

Dissemination of IncFII(K)-type plasmids in multiresistant CTX-M-15-producing Enterobacteriaceae isolates from children in hospital paediatric oncology wards.

In this study, extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae isolates in children with malignancies hospitalised at a paediatric oncology department in the Czech Republic were investigated. From June 2009 to January 2010, a total of 50 ESBL-producing faecal isolates of Enterobacteriaceae were obtained from 28 patients. These isolates were characterised with regard to ESBL enzymes, plasmid-mediated quinolone resistance genes, multilocus sequence typing (MLST) and plasmids conferring resistance to cephalosporins and fluoroquinolones. ESBL-producing isolates included Klebsiella pneumoniae (n=36), Escherichia coli (n=7), Klebsiella oxytoca (n=3), Enterobacter cloacae (n=2) and Citrobacter freundii (n=2). Klebsiella pneumoniae isolates belonged to 7 MLST types, including sequence types ST280, ST321, ST323 and ST416 as well as the novel types ST626, ST627 and ST628. The multiresistant epidemic clone E. coli B2-O25b-ST131 was detected in one patient. The gene bla(CTX-M-15) was found on large conjugative IncFII(K) plasmids along with bla(TEM-1), bla(OXA-1), qnrB1, aac(6')-Ib-cr, strA, sul2, aac(3')-II and tet(A) genes in most isolates. Dissemination of IncFII(K) plasmids among various Enterobacteriaceae isolates was considered an important aspect of nosocomial colonisation in the wards by Enterobacteriaceae species producing ESBLs. This is the first study documenting multiple antibiotic resistance elements, including qnr genes, in IncFII(K) plasmids in various bacterial species isolated in a single hospital department. The results highlight the evolution of IncFII(K) plasmids into new variants containing novel antibiotic resistance elements and their important role in spreading ESBL-producing bacteria among hospitalised patients.

[The disease caused by Clostridium difficile in geriatric patients]. / Onemocnení vyvolané Clostridium difficile u geriatrických nemocných.

BACKGROUND: The disease caused by the bacterium Clostridium difficile/Clostridium difficile associated disease/diarrhoea (CDAD) is becoming a serious problem especially in geriatric patients, who are now relatively often treated by broad-spectrum antibiotics. The goal of our study was to evaluate the occurrence of the risk factors and to evaluate the complex of relations and coherence which lead to the CDAD disease in a selected group of seniors treated at our institution. MATERIAL AND METHODS: The retrospective study evaluated a group of 67 patients with diagnosed CDAD, who were hospitalized at the clinic of internal medicine, geriatrics and practical medicine, Faculty of Medicine and Faculty Hospital in Brno from January 2007 till October 2010. In the study 46 women (68.7%) and 21 men (31.3%) were included of the average age 78.8 +/- 10.3 years (56 till 96 years). The decisive moment in the diagnosis of CDAD was the discovery of enterotoxines A and B in faeces of the patients. RESULTS: The mean time of hospitalization of the patients suffering from CDAD was significantly higher (p = 0.01) in comparison with the control patients (24.63 +/- 16.34 vs. 11.5 +/- 10.7 days). Polymorbidity was also high in those patients. On average, each patient was ill with 11.3 diseases. The most frequent diseases were: high blood pressure (76.1% of the patients), ischemic heart disease 68.7% and the third most frequent diagnosis was the cerebrovascular disease 50.7%. We found that only 13 patients (19.4%) did not take the antibiotics at all, further 54 patients (80.6%) used one or more antibiotics. From the cohort of 67 patients 12 died (17.9%), the section was done in 7 patients, and colitis pseudomembranosa was proved in 3 of them. In 8 cases relapse of the colitis was proved. CONCLUSIONS: The infection of the clostridium is a very serious disease which increases the morbidity and mortality in geriatric patients. Besides the demands on the diagnostics and therapy, it influences also the duration of the hospitalization.

Bacteriocin synthesis in uropathogenic and commensal Escherichia coli: colicin E1 is a potential virulence factor.

BACKGROUND: Bacteriocin production is an important characteristic of E. coli strains of human origin. To date, 26 colicin and 9 microcin types have been analyzed on a molecular level allowing molecular detection of the corresponding genes. The production incidence of 29 bacteriocin types and E. coli phylogroups were tested in a set of 361 E. coli strains isolated from human urinary tract infections (UTI) and in 411 control strains isolated from feces of patients without bacterial gut infection. RESULTS: Production of 17 and 20 individual bacteriocin types was found in the UTI and control strains, respectively. Microcin H47 encoding determinants were found more often among UTI strains compared to controls (37.9% and 27.0% respectively, p = 0.02) and strains producing microcin H47 belonged predominantly to phylogroup B2 when compared to other bacteriocin producers (67.4% and 36.7%, respectively; p < 0.0001). Producers of 3 or more identified bacteriocin types were more common in the UTI group (20.0% compared to 12.4% in controls, p = 0.03). In the UTI strains, there was a markedly higher number of those producing colicin E1 compared to controls (22.1% to 10.2%, respectively, p = 0.0008). Moreover, colicin E1 production was more common in the UTI bacteriocinogenic strains with multi-producer capabilities. As shown by Southern blotting, pColE1 DNA was not recognized by the ColIa probe and vice versa suggesting that pColE1 was independently associated with pColIa in UTI strains. CONCLUSION: E. coli strains isolated from human urinary tract infections showed increased incidence of microcin H47 and colicin E1 production, respectively. Moreover, colicin E1 itself appears to be a potentially important virulence factor of certain uropathogenic E. coli strains.

Identification of lactic acid bacteria isolated from human blood cultures.

Fifteen lactic acid bacterial strains were isolated from blood cultures from 15 different patients in the Faculty Hospital in Brno, Czech Republic. All strains were identified using biochemical tests and repetitive PCR using the (GTG)5 primer. Doubtful identification results were confirmed by whole-cell protein analysis. The strains were assigned to the genera Lactobacillus (eight strains representing seven species), Leuconostoc (six strains representing four species) and Weissella (one strain). Antibiotic susceptibility testing was performed using the E-test and revealed high-level resistance to cotrimoxazol, metronidazole, vancomycin and teicoplanin, but nearly all strains were susceptible to erythromycin, clindamycin, ampicillin and penicillin.