Magdalena Kawalec

Publications of Magdalena Kawalec

• The effect of an antibiotic policy on the control of vancomycin-resistant enterococci outbreak and on the resistance patterns of bacteria isolated from the blood of patients in a hematology unit.

  Authors: Tomasz Ozorowski, Magdalena Kawalec, Maria Zaleska, Lech Konopka, Waleria Hryniewicz

  Polskie archiwum medycyny wewnetrznej. 11/2009; 119(11):712-718.

  INTRODUCTION: Antibiotic resistance has become one of the main medical problems worldwide. This is mainly due to an overuse and misuse of antibiotics. OBJECTIVES: The aim of the study was to assessINTRODUCTION: Antibiotic resistance has become one of the main medical problems worldwide. This is mainly due to an overuse and misuse of antibiotics. OBJECTIVES: The aim of the study was to assess the effect of an antibiotic policy and enhanced infection control on the occurrence of epidemic strains of vancomycin-resistant enterococci (VRE) and resistance patterns of bacteria isolated from the blood of patients hospitalized in two departments of a hematology center in Poland. PATIENTS AND METHODS: Antibiotic use was calculated in daily defined doses (DDD) per 100 patient-days during the two 5-month periods, before and after the introduction of the policy. Infection control measures included a 1-week screening for VRE rectal carriage and contact isolation. RESULTS: Antibiotic consumption decreased from 82.1 to 57.3 DDD per 100 patient-days, mainly because of a decrease in the use of co-trimoxazole, other antimicrobials active against anaerobes, and cephalosporins. A significant change in antibiotic resistance patterns was observed and in vitro efficacy of antibiotics against bacteria isolated from the blood increased remarkably. We managed to eradicate the outbreak of VRE. CONCLUSIONS: The introduction of antibiotic policy and enhanced infection control measures may prove efficacious in VRE control.

• Clonal structure of Enterococcus faecalis isolated from Polish hospitals: characterization of epidemic clones.

  Authors: Magdalena Kawalec, Zbigniew Pietras, Emilia Daniłowicz, Aleksandra Jakubczak, Marek Gniadkowski, Waleria Hryniewicz, Rob J L Willems

  Journal of clinical microbiology. 02/2007; 45(1):147-53.

  To study the population structure of Enterococcus faecalis from Polish hospitals, 291 isolates were typed by pulsed-field gel electrophoresis and a novel multilocus sequence typing scheme (P.To study the population structure of Enterococcus faecalis from Polish hospitals, 291 isolates were typed by pulsed-field gel electrophoresis and a novel multilocus sequence typing scheme (P. Ruiz-Garbajosa et al., J. Clin. Microbiol. 44:2220-2228, 2006). The isolates originated from geographically widespread medical institutions and were recovered during a 10-year period (1996 to 2005) from different clinical sources. The analysis grouped the isolates into five epidemic and 71 sporadic clones. The importance of the previously identified global clonal complexes CC2 and CC9 was corroborated by our findings that two of the Polish epidemic clones, A and J, were classified into these clonal complexes (CCs). However, the two most predominant clones, C (ST40) and F (CC87), did not cluster in the aforementioned CCs and may represent novel epidemic CCs. These clones may have emerged in Central Europe. Clone F, carrying glycopeptide resistance determinants of VanA or VanB phenotypes, caused several outbreaks in hematology units and appeared to be the most prevalent clone in recent years in Poland. Antimicrobial susceptibility testing and additional tests for pathogenicity-related phenotypes (hemolysin and gelatinase production) and genes (asa1 and esp) were performed to further characterize these epidemic clones. Multidrug resistance, glycopeptide resistance, presence of asa1, and production of hemolysin appeared to be statistically significant features related to epidemicity. Production of gelatinase was significant for two of the epidemic clones, whereas presence of the esp gene was not specific for the epidemic clones.

• Molecular diversity of a putative virulence factor: purification and characterization of isoforms of an extracellular serine glutamyl endopeptidase of Enterococcus faecalis with different enzymatic activities.

  Authors: Magdalena Kawalec, Jan Potempa, Jonathan L Moon, James Travis, Barbara E Murray

  Journal of bacteriology. 02/2005; 187(1):266-75.

  A previously identified gene sprE of Enterococcus faecalis strain OG1 was shown to encode an extracellular serine protease that appears to belong to the glutamyl endopeptidase I staphylococcal group.A previously identified gene sprE of Enterococcus faecalis strain OG1 was shown to encode an extracellular serine protease that appears to belong to the glutamyl endopeptidase I staphylococcal group. A single form of SprE with a molecular mass of 25 kDa and a pH optimum between 7.0 and 7.5 was isolated from culture supernatant of wild-type E. faecalis strain OG1RF (TX4002); this form was apparently generated by cleavage of the Ser-1-Leu1 and Arg230-Leu231 peptide bonds of the secreted zymogen. In contrast, the culture supernatant of the gelatinase-null mutant, TX5264, with a nonpolar deletion of gelE which encodes the E. faecalis gelatinase, was found to contain several forms of SprE proteolytically processed on both the N and C termini; in addition to a full-length zymogen and a truncated zymogen, three mature forms of the SprE proteinase, Leu1-Ala237, Ser-1-Glu227, and Leu1-Glu227, were identified. As with the V8 proteinase of Staphylococcus aureus, the closest homologue of SprE, all of the active forms cleaved specifically Glu-Xaa peptide bonds but with substantially different efficiencies, while none was able to hydrolyze peptide bonds with Asp in the P1 position. The most active of all these enzyme forms against several substrates, including human fibrinogen and beta-chain insulin, was the Ser-1-Glu227 (-1S-SprE) isolated from TX5264; -1S-SprE, in contrast to other forms of SprE, was unstable at 37 degrees C, apparently due to autodegradation. In conclusion, our results demonstrate that sprE encodes a highly specific serine-type glutamyl endopeptidase, the maturation of which is dependent on the presence of gelatinase. In the absence of gelatinase activity, the aberrant processing of pro-SprE results in the appearance of a "superactive" form of the enzyme, -1S-SprE.

• An Enterococcus faecium secreted antigen, SagA, exhibits broad-spectrum binding to extracellular matrix proteins and appears essential for E. faecium growth.

  Authors: Fang Teng, Magdalena Kawalec, George M Weinstock, Waleria Hryniewicz, Barbara E Murray

  Infection and immunity. 10/2003; 71(9):5033-41.

  A gene encoding a major secreted antigen, SagA, was identified in Enterococcus faecium by screening an E. faecium genomic expression library with sera from patients with E. faecium-associatedA gene encoding a major secreted antigen, SagA, was identified in Enterococcus faecium by screening an E. faecium genomic expression library with sera from patients with E. faecium-associated endocarditis. Recombinant SagA protein showed broad-spectrum binding to extracellular matrix (ECM) proteins, including fibrinogen, collagen type I, collagen type IV, fibronectin, and laminin. A fibrinogen-binding protein, purified from culture supernatants of an E. faecium clinical isolate, was found to match the N-terminal sequence of the predicted SagA protein and to react with the anti-SagA antibody, confirming that it was the SagA protein; this protein appeared as an 80- to 90-kDa smear on a Western blot that was sensitive to proteinase K and resistant to periodate treatment and glycoprotein staining. When overexpressed in E. faecium and Escherichia coli, the native and recombinant SagA proteins formed stable oligomers, apparently via their C-terminal domains. The SagA protein is composed of three domains: (i) a putative coiled-coil N-terminal domain that shows homology to the N-terminal domain of Streptococcus mutans SagA protein (42% similarity), previously shown to be involved in cell wall integrity and cell shape maintenance, and to the P45 protein of Listeria monocytogenes (41% similarity); (ii) a central domain containing direct repeats; and (iii) a C-terminal domain that is similar to that found in various proteins, including P45 (50% similarity) and P60 (52% similarity) of L. monocytogenes. The P45 and P60 proteins both have cell wall hydrolase activity, and the latter has also been shown to be involved in virulence, whereas cell wall hydrolase activity was not detected for SagA protein. The E. faecium sagA gene, like the S. mutans homologue, is located in a cluster of genes encoding proteins that appear to be involved in cell wall metabolism and could not be disrupted unless it was first transcomplemented, suggesting that the sagA gene is essential for E. faecium growth and may be involved in cell wall metabolism. In conclusion, the extracelluar E. faecium SagA protein is apparently essential for growth, shows broad-spectrum binding to ECM proteins, forms oligomers, and is antigenic during infection.

• Susceptibility patterns of Enterococcus spp. isolated in Poland during 1996

  Authors: Waleria Hryniewicz, Tomasz Zarȩba, Magdalena Kawalec

  International Journal of Antimicrobial Agents.

  Susceptibility of Enterococcus spp. isolated from various clinical specimens to different antimicrobial agents was evaluated. Of the 346 enterococcal isolates obtained from four regional PolishSusceptibility of Enterococcus spp. isolated from various clinical specimens to different antimicrobial agents was evaluated. Of the 346 enterococcal isolates obtained from four regional Polish hospitals during 6 months of 1996, 261 (75.4%) were identified as Enterococcus faecalis, 75 (21.7%) as Enterococcus faecium and ten (2.9%) as other enterococcal species. High-level resistance to gentamicin was expressed by 33.4% of E. faecalis and 86.5% of E. faecium strains and corresponding streptomycin resistance by 43.9 and 82.4%, respectively. Over 80% of E. faecium isolates were resistant to ampicillin. None of the isolates was resistant to teicoplanin, however 7.9% of E. faecalis and 1.4% of E. faecium strains were moderately susceptible to vancomycin.