Prediction of antifungal activity of gemini imidazolium compounds.

The progress of antimicrobial therapy contributes to the development of strains of fungi resistant to antimicrobial drugs. Since cationic surfactants have been described as good antifungals, we present a SAR study of a novel homologous series of 140 bis-quaternary imidazolium chlorides and analyze them with respect to their biological activity against Candida albicans as one of the major opportunistic pathogens causing a wide spectrum of diseases in human beings. We characterize a set of features of these compounds, concerning their structure, molecular descriptors, and surface active properties. SAR study was conducted with the help of the Dominance-Based Rough Set Approach (DRSA), which involves identification of relevant features and relevant combinations of features being in strong relationship with a high antifungal activity of the compounds. The SAR study shows, moreover, that the antifungal activity is dependent on the type of substituents and their position at the chloride moiety, as well as on the surface active properties of the compounds. We also show that molecular descriptors MlogP, HOMO-LUMO gap, total structure connectivity index, and Wiener index may be useful in prediction of antifungal activity of new chemical compounds.

Antimicrobial activity and SAR study of new gemini imidazolium-based chlorides.

A series of 70 new 3,3'(α,ω-dioxaalkyl)bis(1-alkylimidazolium) chlorides were synthesized. They were characterized with respect to surface active properties and antimicrobial activity against the following pathogens: Staphylococcus aureus, Enterococcus faecalis, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Candida krusei, and Candida albicans. In this article, besides description of the synthesis, we characterize a set of features of these compounds, concerning their structure (described by the length of the dioxaalkan spacer and the length of the alkyl substituent in the aromatic ring) and surface active properties (critical micelle concentration, value of surface tension at critical micelle concentration, value of surface excess, molecular area of a single particle, and free energy of adsorption of molecule). Then, we present a SAR study for Staphylococcus aureus, as one of the most widespread pathogenic strains, conducted with the help of the Dominance-based Rough Set Approach (DRSA), that involves identification of relevant features and relevant combinations of features being in strong relationship with a high antimicrobial activity of the compounds. The SAR study shows, moreover, that the antimicrobial activity is dependent on the type of substituents and their position at the chloride moiety, as well as on the surface active properties of the compounds.

[The evaluation of lipolytic activity of strains of Enterococcus faecium]. / Ocena aktywnosci lipolitycznej szczepów Enterococcus faecium.

INTRODUCTION: Little is known about the involvement of hydrolytic enzymes such as lipases as virulence factors in infections involving Enterococcus spp. METHODS: A total of 45 isolates of E. faecium were investigated. Lipolytic activity of enterococcal strains was determined by Tryptic Soy Agar containing Tween 20, Tween 40, Tween 60, Tween 80 and egg yolk. RESULTS: We detected that E. fecium strains produced lipases more frequently on Tween 20 agar (71.1% strains) than on Tween 40 agar, Tween 60 agar, Tween 80 agar, egg yolk agar (respectively 33.3%, 24.4%, 20.0%, 31.1%). Our results indicate that lipase may be a virulence factor in E. faecium. CONCLUSIONS: Studies suggest that source of isolation from clinical materials (blood, wound and fluid from the abdominal cavity) does not have an influence on the ability hydrolysis esters.

[High level of aminoglycoside resistance among Enterococcus faecalis and Enterococcus faecium strains]. / Opornosc na wysokie stezenia aminoglikozydów wsród szczepów Enterococcus faecalis i Enterococcus faecium wyosobnionych z materialu klinicznego.

Enterococcus sp. strains are believed as important reason of serious nosocomial infections currently. These infections are cured by using combination of beta-lactams and aminoglycosides for their treatment. Enterococcus sp. resistant to high-level doses of aminoglycosides, beta-lactams and vancomycin are responsible for therapeutic failure. The aim of our study was to evaluate the incidence of isolation and susceptibility to antibiotics of HLAR Enterococcus sp. strains isolated between 2007 and 2010 from the patients of University Hospital No. 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Torun. Amongst 6137 Enterococcus sp. strains 1124 (18,3%) presented HLAR phenotype; 53,1% of them was identified as E. faecalis and 46,9% as E. faecium. The highest percentage of all examined strains was isolated from the patients of different surgery clinics, Intensive Care Units, and Pediatrics, Hematology and Oncology Clinic. HLAR and HLSR phenotypes were noted in E. faecalis, for 45,7% and 27,5% strains, in E. faecium - 29,8% and 9,5%, respectively. HLGR phenotype was presented twice more often in E. faecium than E. faecalis. Highest percentages of E. faecium resistant to glycopeptides and rifampicin were observed when compared with E. faecalis. The highest percentages of strains intermediate, resistant to vancomycin and resistant to glycopeptides were noted for E. faecium strains with phenotypes HLAR, HLGR and HLSR.

[Incidence of alginate-coding gene in carbapenem-resistant Pseudomonas aeruginosa strains]. / Wystepowanie genu kodujacego alginian u szczepów Pseudomonas aeruginosa opornych na karbapenemy.

Pseudomonas aeruginosa rods are one of the most common isolated opportunistic nosocomial pathogens. Strains usually are capable to secret a capsule-like polysaccharide called alginate important for evasion of host defenses, especially during chronic pulmonary disease of patients with cystic fibrosis. Most genes for alginate biosynthesis and lysis are encoded by the operon. The aim of our study was to evaluate the incidence of algD sequence, generally use for alginate-coding gene detection, in 120 P. aeruginosa strains resistant to carbapenems. All isolates were obtained in the Department of Clinical Microbiology University Hospital no. 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Torun. Examined strains demonstrated resistance to carbenicillin (90,0%), ticarcillin (89,2%) and ticarcillin clavulanate (86,7%). All strains were susceptible to colistin. The majority of examined strains was susceptible to ceftazidime and cefepime (40,8% each) and norfloxacin (37,5%). Presence of algD gene - noted in 112 (93,3%) strains proves that not every strain is capable to produce alginate. It was also found out that differences in algD genes incidence in case of different clinical material that strains were isolated from were not statistically important.

[Salmonella spp. strains resistant to drugs]. / Szczepy Salmonella sp. oporne na leki przeciwbakteryjne.

The aim of the study was retrospective analysis of Salmonella spp. strains isolated from patients of State Infectious Diseases Observatory Hospital of T. Browicz in Bydgoszcz (SZAK) and University of dr. A. Jurasz in Bydgoszcz (SU CM UMK) in 2006-2009. The percentages of Salmonella spp. strains resistant to at least one drug were: 19,0% in 2006, 12,5% in 2007, 50,6% in 2008 and 43,8% in the first half of 2009 year. The highest number of Salmonella spp. strains resistant to drugs were isolated from stool (96,7%) and from patients of SZAK (83,3%). Among all isolated Salmonella spp. strains resistant to drugs the highest percentage were S. enterica serovar Enteritidis (56,7%). Among S. enterica bacilli predominated resitant phenotypes to ampicillin, amoxicillin, chloramphenicol and nalidixic acid. The increasing number of strains resistant to ciprofloxacin (0,0 - 26,7%) and high percentage of strains resistant to nalidixic acid (97,3%) were noted. Decreasing resistance to chloramphenicol was observed in our study (54,5 - 14,3%).

[Frequency of isolation and susceptibility to antibiotics of Escherichia coli strains isolated from blood]. / Czestosc izolacji i lekoopornsc szczepów Escherichia coli wyosobnionych z krwi.

The aim of our study was the analysis of Escherichia coli strains obtained from patients of University Hospital No 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Torun and State Infectious Diseases Observatory Hospital of T. Browicz in Bydgoszcz, between 2007 and 2010. Among all microorganisms isolated from blood was 8.7% E. coli strains and 45.1% of all rods from Enterobacteriaceae family. Number of E. coli isolations from positive blood samples was: 64 in 2007, 69 in 2008, 77 in 2009 and 26 in the first half of 2010 year. The highest percentage of E. coli strains were obtained from patients of the Transplantology and Surgery Clinic (16.1%), the Nephrology and Internal Diseases Clinic with the Dialysis Centre (14.0%), the Pediatric, Hematology and Oncology Clinic (13.6%) and the Anesthesiology and Intensive Care Clinic (13.6%). All analysed strains were susceptible to carbapenems, amikacin and tygecycline. The highest percentage of resistant strains were observed to ampicillin (70.7%), piperacillin (43.9%), tetracycline (42.8%) and doxycycline (38.8%). During four years of study 4 (6.3%), one, three and two E. coli strains with ESBL were isolated, respectively.

[Influence of ciprofloxacin on the ability of production of staphylococcin T in Staphylococcus cohnii (StT)]. / Wplyw ciprofloksacyny na zdolnosc wytwarzania stafylokokcyny T Staphylococcus cohnii (StT).

The aim of this study was to evaluate the influence of ciprofloxacin in a concentration of 0.25 microg/ml on the ability of synthesis of staphylococcin T (StT) Staphylococcus cohnii at 37 degrees C after 24 and 48 hours incubation. Ciprofloxacin in concentration of 0.25 microg/ml after 24 hours incubation inhibits antistaphylococcal activity StT produced by S. cohnii, while after 48 hour incubation, S. cohnii StT is excreted on the same level, in the presence and in the absence of ciprofloxacin.

[Vancomycin-resistant Enterococcus spp. strains]. / Enterococcus sp. oporne na wankomycyne.

The aim of our study was to evaluate a frequency of isolation and susceptibility to antibiotics of vancomycin-resistant enterococci isolated between 2005 and the first half of the 2009 from patients of University Hospital of Dr. A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruli. Study shows increasing frequency of VRE isolation from two in 2005, 8 in 2006, 30 in 2007 to 79 in 2008 and 40 in the first half of 2009 year. Among all isolated VRE strains E. faecium definitely predominated (75.0-90.0% in 2006-2009). The majority of strains were obtained from patients of the Pediatrics, Hematology and Oncology Clinic (43,4%) and Pediatric Surgery Clinic (41.5%). VRE strains were mainly isolated from digestive tract (79,9%). The isolates demonstrated frequently resistance to penicillin, ampicillin, ciprofloxacin, rifampicin and chloramphenicol. Percentage of VRE strain resistant to aminoglycosides decreased during the last four years of study. Over 56% of VRE isolates showed resistance to teicoplanin. Linezolid and quinupristin-dalfopristin were the only drugs presenting activity against isolated VRE strains.

[Influence of staphylococcin T on Enterococcus sp. growth]. / Oddzialywanie stafylokokcyny T na wzrost Enterococcus sp.

Bacteriocins are ribosomally synthesised, extracellular bacterial products. Generally, spectrum of inhibition is limited to the same or closely related species to bacteriocin producer. Staphylococcin T is produced by Staphylococcus cohnii strain. The present study concerns influence of StT to 267 Enterococcus sp. strains growth isolated between 2003 and 2006 in Department of Microbiology University Hospital of dr. A. Jurasz in Bydgoszcz. S. cohnii T antagonistic ability evaluated towards bacteries on Mueller-Hinton Agar (bio Mérieux) in aerobic conditions. After 24 and 48 hours tested enterococci suspensions were plated perpendiculary. Susceptibility to antibiotics was assessed by disc diffusion method according to the guideless of Clinical and Laboratory Standards Institute and National Reference Centre for Antimicrobial Susceptibility. Among Enterococcus sp. strains tested 7.1% were sensitive to StT. The highest percentage of sensitive enterococci isolated from wound swabs, urine, blood and pus. Enterococcus faecium strains dominated (63.2%) among enterococci sensitive to StT. Moderate inhibition degree on S. cohnii T bacteriocin action was observed in majority sensitive enterococci strains. Enterococcus sp. sensitive to StT strains were frequently multidrug resistant (68.4%). According to the study results and increasing resistance to antibiotics, StT could be an alternative agent used to treat infections caused by Enterococcus sp.