[Evaluation of selected properties of morphological variants of Acinetobacter baumannii complex]. / Ocena wybranych wlasciwosci morfologicznych wariantów paleczek Acinetobacter baumannii complex.

INTRODUCTION: The ability of growth of Acinetobacter baumannii as morphology colony variants have been observed. However, the importance of this phenomenon for its biology is not known. The aim of this study was to evaluate some properties of light and dark morphology colony variants. METHODS: Fifty two isolates were identified by MALDI TOF MS method (MALDI Biotyper, BRUKER). It was evaluated the adhesion to polystyrene and extracellular mucus production of morphology colony variants and its susceptibility to imipenem and meropenem by agar dilution method. RESULTS: Forty eight (92.3%) out of the 52 morphotypes Acinetobacter sp. were identified as A. baumannii, two (5.8%) as A. genomospecies 3, one as the A. calcoaceticus. Sixteen (61.0%) pairs of isolates showed differences in the similarity of the spectra to the spectra of reference strains in the MALDI-TOF MS method. Adhesion to polystyrene was observed in all dark and 92.3% light morphotypes. Extracellular slime was produced by 15 (57.7%) dark morphotypes, and 7 (26.9%) of clear. The differences in susceptibility to imipenem occurred in two (7.7%), and meropenem in three (11.5%) pairs of morphotypes. CONCLUSIONS: The results show diversity of biological properties of morphology colony variants of A. baumannii complex. Differences in the level of adhesion to polystyrene and slime production may indicate the importance of morphological differentiation in virulence of A. baumannii complex.

[Adhesion and slime production by wild and clinical strains of Acinetobacter baumannii]. / Adhezja oraz wytwarzanie sluzu zewnatrzkomórkowego przez dzikie i kliniczne szczepy paleczek Acinetobacter baumannii.

INTRODUCTION: Adhesion of bacteria to the surface plays a key role in the development of infection, and is the first stage of biofilm formation. The ability of A. baumannii strains to adhesion and forming biofilms on abiotic surfaces, as well as eucaryotic cells was described.A. baumannii is also capable of secretion of the exopolysaccharide (EPS) - a substance that allows the binding of bacterial cells to the surface, and with each other. The aim of this study was to evaluate the ability of biofilm formation and slime production by wild-type and clinical strains of A. baumannii. METHODS: We examinated 51 strains ofA. baumannii, including 14 isolated from lower respiratory tract, 17 from wound swabs and 20 from the soil. Adhesion to polystyrene was evaluated by modified Christensen methods and slime production by Ishiguro method. RESULTS: Adhesion to polystyrene was observed in 51,0% of strains, including 70,0% of wild-type and 38,7% of clinical strains (64,7% strains from wound swabs and one strain from lower respiratory tract). Slime production was found in 31,4% of strains, of which the largest (42.9%) group strains were isolated from lower respiratory tract. There was no correlation between production of extracellular slime, and the adhesion of strains to polystyrene. CONCLUSIONS: Different levels of expression of virulence factors in A. baumannii strains isolated from different origin indicates their importance in the colonisation ecological niches and the development of infections at various sites.

[Antibiotic sensitivity of beta-hemolytic streptococci isolated from throat swabs and purulent material]. / Lekowrazliwosc paciorkowców beta-hemolizujacych izolowanych z wymazów z gardla i materialu ropnego.

The aim of this study was to evaluate the prevalence and susceptibility of beta-hemolytic streptococci isolated from throat swabs (142--29.9%) and purulent material (333--70.1%) taken from patients treated at University Hospital dr. A. Jurasz in Bydgoszcz Collegium Medicum. L. Rydygier in Bydgoszcz, Nicolaus Copernicus University in Torun in 2005-2009. Of the 475 tested strains, 156 (32.8%) were identified as S. pyogenes. This species accounted for 38.8% of strains isolated from purulent material and 19.0% of swabs from the throat. Among the strains isolated from throat swabs of 62 (43.7%) were identified as Streptococcus group C. Only 5.1% strains were identified as Streptococcus group F. All strains of beta-hemolytic streptococci were susceptible to ampicillin or penicillin, fluoroquinolones, vancomycin and linezolid. Erythromycin-susceptible strains was 83.8%, and 89.1% for clindamycin. A total of 51.3% of erythromycin resistance strains had the cMLS(B) phenotype (63.3% for strains from throat swabs and 46.3% of the purulent materials). Sensitivity to tetracycline was characterized by 51.2% of strains of beta-hemolytic streptococci. The percentage of strains susceptible to this antibiotic among isolates from throat swabs was 63.1%, and purulent material--48.0%. The lowest percentage of strains susceptible to tetracycline (14.1%) were found among S. agalactiae and Streptococcus group G (33.6%) strains. During the study time, saw an increase in the percentage of strains susceptible to tetracycline and erythromycin.

[Carbapenem-resistant Acinetobacter baumannii strains]. / Szczepy acinetobacter baumannii oporne na karbapenemy.

A. baumannii rods are opportunistic pathogens responsible generally for nosocomial infections. Resistance to carbapenems, observed among them, is a serious threat due to ability to be transmitted between bacterial species. The aim of our study was to evaluate the frequency of isolation and susceptibility to antibiotics of resistant to imipenem and/or meropenem A. baumannii strains isolated between 2007 and 2009 from patients of University Hospital of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Torun. Study shows increasing frequency of isolation that type of strains from 4 in 2007 to 95 in 2008 and 67 in 2009. Percentage of imipenem-resistant isolates raised to 27.6% in 2008 and 31.0% in 2009. Meropenem-resistant A. baumannii isolates frequency changed from 2.1% in 2007 to 31.2% and 34.6%, in 2008 and 2009, respectively. The majority of strains were obtained from patients of the Intensive Care Units and surgery clinics. Examined A. baumannii strains were generally isolated from bronchoalveolar lavage (25.3%) and wound (18.1%) or throat (12.0%) swabs samples. The isolates demonstrated full resistance to norfloxacin, ciprofloxacin, and chloramphenicol. Ampicillin/sulbactam (24.8%), tobramycin (8.1%) and colistin (1.5%) presented the highest in vitro activity against isolated strains.

[Evaluation of occurrence of Alcaligenes faecalis in clinical samples of patients of the university hospital in Bydgoszcz]. / Udzial paleczek Alcaligenes faecalis w zakazeniach pacjentów szpitala uniwersyteckiego w Bydgoszczy.

Alcaligenes faecalis is an aerobic Gram-negative, non-fermentative rod. It's saprophyte of water and soil. It may be recovered from wet places of hospital environment. It is considered as an opportunistic pathogen. The aim of this review was evaluation of occurrence in clinical samples and susceptibility to antibiotics of 72 A. faecalis strains isolated in years 2003-2008. Over 30% of strains were isolated from patients in surgical ward, 19.6% from patients in outpatient clinic and almost 14% from patients in Department of Dermatology. 70.8% of strains were isolated from purulent material samples, whereas from urine--16.7% of strains. Nearly 88% out of examined strains were grown in mixed culture together with one (26.4%), two (32.0%), three (23.6%) or four (5.6%) microorganisms. All out of strains were sensitive to piperacyline, piperacyline/tazobactam and carbapenems. Sensitivity to aztreonam was observed at 22.2% of strains and to co-trimoxazole at 57.1% of strains.

The influence of staphylococcin T (StT) on the mouse fibroblasts (3T3) viability, an in vitro experiment.

Staphylococcin T (StT) is a bacteriocin, which can serve as an antibiotic. The influence of StT on the mammalian cells viability should be examined before its possible applications. The aim of this work was to study the influence of StT on mouse fibroblasts viability in vitro. StT was delivered as a deposit in agar. 3T3 fibroblasts were used in viability tests. Cells were incubated with StT for 24 and 48 h. In the first controls, cells grew without the agar block, in the second controls, the agar block contained no StT. Trypan blue exclusion test was performed. Growth inhibition of sensitive strain SAU-209P was observed after 24 h incubation with cell culture medium containing StT. Antimicrobial activity of StT in culture medium was confirmed even after 2 months. The viability of 3T3 cells in the second control group was 50% lower than in the first and 25% higher than in StT treated group during the first day. It was noticed mechanical damage of growing cells caused by agar blocks. The number of cells cultured with StT was similar to that of second control group after 2 days. There were no changes in morphology of cells in all groups. It follows that StT had unimportant influence on the fibroblasts (3T3) viability in culture. StT may be considered for future animal trails.

[Hydrolytic and haemolytic activity of Klebsiella pneumoniae and Klebsiella oxytoca]. / Hydrolityczna i hemolitycznaaktywnosc paleczek Klebsiella pneumoniae i Klebsiella oxytoca.

Hydrolytic enzymes and haemolysins are important extracellular substances produced by many bacteria. We investigated 57 K. pneumoniae strains and 40 K. oxytoca strains isolated from clinical materials. We estimated the ability to produce: proteases hydrolyzing milk powder, caseinase, gelatinase, elastase, lecithinase, lipases, DNase and haemolysins on human, sheep and horse erythrocytes on TSA medium with or without 5% Egg Yolk. We detected that K. oxytoca strains produced proteases hydrolyzing milk powder (37.5%), caseinase (15.0%) and gelatinase (17.5%) more frequently than K. pneumoniae strains (respectively 21.0%, 5.3%, 8.9%). None of the analysed Klebsiella spp. strains produced elastase. Only K. pneumoniae strains produced lecithinase (5.3%). Lipases hydrolyzing Tween were produced from 3.5% (for Tween 60 and 80) to 7.0% (for Tween 20). Among K. oxytoca strains only one (2.5%) hydrolyzing Tween 20. DNase was produced by 38.6% of K. pneumoniae strains and by 27.5% K. oxytoca strains. Haemolytic properties on human erythrocytes were detected in 5.3% K. pneumoniae strains on TSA medium and 29,8% on medium with Egg Yolk. In K. oxytoca strains haemolytic properties on human erythrocytes were detected only on medium with Egg Yolk (12.5%). Haemolytic properties on sheep erythrocytes were detected respectively in 21.0% and 22.8% K. pneumoniae strains and in 7.5% K. oxytoca strains on each medium. Haemolytic properties on horse erythrocytes were detected respectively in 33.4% and 52.6% K. pneumoniae strains and in 15.0% and 20.0% K. oxytoca strains.