E Rozynek

Children's Memorial Health Institute, Warszawa, Masovian Voivodeship, Poland

Are you E Rozynek?

Claim your profile

Publications (35)45.73 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Campylobacter spp. is an important cause of gastroenteritis in humans throughout the world. However, sources of these infections are often difficult to identify. Therefore, this study aimed at analyzing the genetic relatedness of Campylobacter isolates from environmental and food samples as well as stool specimens of diarrheal patients obtained in a single geographic region in Poland. Only a few Campylobacter jejuni isolates (4/18, 22%) could be assigned to one cluster, whereas the majority were unrelated. In contrast, the majority of Campylobacter coli strains (25/35, 71%) belonged to three pulsed-field gel electrophoresis (PFGE) clusters containing isolates of various origins (i.e., water samples, chicken carcasses, and humans). Isolates belonging to the clusters showed also similar antibiotic resistance patterns and similar genotypes with respect to the occurrence of the virB11 and iam genes. This suggests that Campylobacter strains may circulate between humans, poultry, and recreational water sources in the rural region in central Poland.
    No preview · Article · Dec 2009 · Foodborne Pathogens and Disease
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study analysed the pattern of antibiotic resistance in 251 Campylobacter strains isolated from symptomatic children hospitalized in 4 large paediatric hospitals in Poland from 2000 through 2007. The highest resistance was found for ciprofloxacin (49.5% for C. jejuni and 51.3% for C. coli), followed by tetracycline (17.5% and 18.0%, respectively), and ampicillin (13.2% and 10.2%, respectively). Almost all isolates were susceptible to macrolides. As much as 22.6% of C. jejuni and 25.6% of C. coli were resistant to more than one class of antimicrobial agents. Multidrug resistance (defined as resistance to at least two classes of antimicrobials) rose significantly from 5.1% in 2000-2003 to 34.6% in 2004-2007.
    Full-text · Article · Jan 2009 · Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate IL-18 mRNA expression in the gastric mucosa in Helicobacter pylori-infected children and its association with macrophage infiltration, IL-8, and IL-1 beta mRNA expression. From 39 children, blood samples were taken for IL-1 beta gene polymorphism analysis and antral biopsies were obtained for histology (including macrophage immunostaining), culture and semiquantitative analysis of IL-18, IL-8, IL-1 beta, and CD14 mRNA expression by reverse transcription-PCR (RT-PCR). RT-PCR was used for H. pylori ureA and cagA mRNA detection in gastric tissue. H. pylori-infected patients had significantly higher IL-18, IL-8, and IL-1 beta transcript levels and macrophage numbers in the antral mucosa than H. pylori-negative children. IL-1 beta-511/31 gene polymorphism had no impact on gastric IL-1 beta mRNA levels. IL-18 mRNA expression correlated with mRNA expression of IL-8 and IL-1 beta, and transcript levels of all three cytokines were associated with macrophage infiltration and CD14 mRNA expression in the gastric tissue. Significant correlation was also observed between macrophage numbers and histological parameters of gastritis. These results suggest that interleukin(IL)-18 and macrophages may have an important function in gastric inflammatory response to H. pylori infection in children. IL-18, and possibly CD14 receptor signalling pathway, may be involved in macrophage activation and subsequent IL-8 and IL-1 beta release.
    No preview · Article · May 2008 · European Journal of Gastroenterology & Hepatology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Campylobacter-associated gastroenteritis remains an important cause of morbidity worldwide, and some evidence suggests that poultry is an important source of this foodborne infection in humans. This study was conducted to analyze the prevalence and genetic background of resistance of 149 Campylobacter jejuni and 54 Campylobacter coli strains isolated from broiler chicken carcasses and from stool samples of infected children in Poland from 2003 through 2005. Nearly all isolates were susceptible to macrolides and aminoglycosides. The highest resistance in both human and chicken strains was observed for ciprofloxacin (more than 40%), followed by ampicillin (13 to 21%), and tetracycline (8 to 29%). Resistance to ampicillin and tetracycline rose significantly between 2003 and 2005. Slight differences in resistance between human and chicken isolates indicate that although chicken meat is not the only source of Campylobacter infection in our population, it can be involved in the transmission of drug-resistant Campylobacter strains to humans.
    Preview · Article · Apr 2008 · Journal of food protection
  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: The most recent Polish guidelines on the management of the Helicobacter pylori (H. pylori) infection were published in 2004. Due to a progressive understanding the epidemiology of H. pylori infection, a better understanding of the relationship between the microorganism and its host, the critical need for evaluating the effect of H. pylori infection on diseases outside the digestive tract, and the constant need to evaluate changes in its susceptibility to antibacterial treatment; it is necessary to perform regular updates of the H. pylori treatment guidelines. In Poland, the percentage of the infected adult population is very high and amounts to more than 84%. The H. pylori resistance to medicines is one of the main factors affecting the effectiveness of the eradication treatment. The studies that have been carried out in Poland, in the recent years show strong resistance of the H. pylori strains to clarithromycin (CL) and metronidazole (MTZ) and full sensitivity to amoxicillin (AMX), ciprofloxacin, and tetracycline. The total sensitivity to CL is 28%, whereas the primary and secondary sensitivity - 22% and 54%, respectively. The primary sensitivity to CL is much higher with respect to the strains isolated from children (28%) than those isolated from adults (15%) and it is diversified in various geographical regions (0-33%). The total of 46% H. pylori strains is resistant to MTZ, with the primary and secondary resistance of 41% and 68%, respectively. As much as 20% strains are resistant to CL and MTZ simultaneously. In 2005, the European Helicobacter pylori Study Group developed updated guidelines (Maastricht III) that were published in 2007. The current study includes the revised guidelines on the treatment of H. pylori in Poland, in children and adults recommended by the Polish Society of Gastroenterology. The tests recommended in the diagnosis of H. pylori infection: If it is planned to perform an endoscopy, a biopsy of the mucous membrane for rapid urease test or histological examination should be taken. In other group of patients by means of non-invasive tests, quantitative evaluation of the H. pylori-specific IgG antibodies, 13C-urea breath test ( 13C-UBT), and Helicobacter pylori stool antigen test (SAT) should be performed. Indications for the eradicative treatment of H. pylori infection in adults: 1. active or previous stomach or duodenal ulcer (in case of a bleeding ulcer, the eradication is possible after stopping the bleeding), 2. peptic ulcer operation, 3. gastritis (exacerbated by aphthae), 4. preneoplastic changes (atrophic inflammation, metaplasia, dysplasia), 5. gastric resection due to premature cancer, 6. gastric cancer in the family (up to the second degree of consanguinity), 7. adenomatous and hyperplastic polyps in the stomach (after removing them), 8. gastric MALT lymphoma, 9. Ménétrier's disease, 10. functional dyspepsia, 11. long-term NSAID treatment, 12. anaemia due to iron deficiency for unknown reasons, 13. idiopathic thrombocytopenia, 14. at patient's request (after consulting a doctor). Indications not recommended for the eradication treatment: 1. patients without any clinical symptoms (and with no risk factors of gastric cancer), 2. GERD treatment (except for patients with a projected long-term proton pump inhibitor (PPI) treatment), 3. superficial, chronic gastritis, 4. diseases outside the digestive tract (except for the idiopathic thrombocytopenia and anaemia due to iron deficiency for unknown reasons). The lines of treatment: The first-line treatment: PPI, AMX, MTZ or PPI, (traditional dosage), CL, MTZ or PPI, AMX, CL twice a day for 10 to 14 days. The second-line treatment: PPI, AMX, MTZ, tetracycline or PPI, AMX, MTZ, bismuth salts (if available). The treatment may be prolonged to 14 days if the previous treatment was 10 day-long. The third-line treatment: (a) sensitivity evaluation of the isolated strains to antibiotics recommended for eradication treatment (AMX, MTZ, CL, tetracycline), (b) possible introduction of levofloxacin (if available) along with AMX, (c) adding a probiotic (if it has not been applied before), (d) extension of treatment to 14 days (if the previous treatment periods were shorter). Indications for the treatment of H. pylori in children: 1. active or previous stomach or duodenal ulcer, 2. chronic gastritis irrespective of how advanced, 3. long-term NSAID treatment and immunosuppressive treatment, 4. anaemia due to iron deficiency, 5. idiopathic thrombocytopenia. Treatment of children: Therapies follow as in adults. Dosage depends on the child's body weight: omeprazole: 1 mg/kg of body weight per 24 h, maximum 20 mg/24 h twice-daily, AMX: 40-60 mg/kg of body weight per 24 h, maximum 1000 mg twice a day, CL: 15 mg/kg of body weight per 24 h, maximum 500 mg twice a day; MTZ: 20 mg/kg of body weight per 24 h, bismuth citrate: 8 mg/kg of body weight per 24 h, maximum 240 mg twice a day. The effectiveness evaluation of the H. pylori eradication treatment: Follow-up tests for the evaluation of the eradication are performed not sooner than 4 weeks, preferably 6-8 weeks after the completion of the treatment. Non-invasive tests should be performed, except for the blood H. pylori antibody test, since a successful eradication may keep their titre increased for many months or even years. The breath test of high sensitivity and specificity is recommended as the best choice of follow-up tests. Another alternative is the evaluation of the Helicobacter pylori stool antigen test with the use of monoclonal antibodies. However, this test is less sensitive in comparison with the breath test.
    No preview · Article · Jan 2008 · Gastroenterologia Polska

  • No preview · Article · Mar 2007 · International Journal of Antimicrobial Agents
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: An association between Helicobacter infection and autoimmune hepatitis (AIH) in children was investigated. The prevalence of antibodies to H. pylori did not differ between the AIH and the control group, (22% versus 14%), and antibodies to non-gastric Helicobacter were not detected in either group. H. pylori DNA was found in two AIH liver tissues, but Helicobacter was not cultured from any sample.
    Preview · Article · Feb 2006 · Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists
  • [Show abstract] [Hide abstract]
    ABSTRACT: The resistance of Helicobacter pylori to antimicrobials, known to be increasing in many countries, is an important factor compromising the efficacy of eradication therapy. Therefore, our study aimed at analysing the current susceptibility status of H. pylori in Poland. A total of 337 H. pylori isolates were cultured from children (N=179) and adults (N=158) from various regions of the country from January 2001 to December 2004. All strains were susceptible to amoxicillin and tetracycline. The overall resistance to clarithromycin (CL) was 28%, but there were significant differences between the centres (ranging from 0% to 33%) and between child and adult isolates (28% versus 15%, respectively; P=0.01) for primary a resistance. Altogether, 46% of H. pylori isolates were resistant to metronidazole (MTZ) and 20% of isolates were simultaneously resistant to CL and MTZ.
    No preview · Article · Oct 2005 · International Journal of Antimicrobial Agents
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The pathogenicity of thermotolerant Campylobacter species, common food-borne pathogens, depends on certain factors unevenly distributed among strains of different origin. The prevalence of such markers has never been examined in a population of Polish Campylobacter strains of human and poultry origin. Therefore, we analysed the presence of the cadF, cdtA, cdtB and cdtC genes and the iam sequence in Campylobacter jejuni (n = 115) and Campylobacter coli (n = 57) isolates from children with diarrhoea and from chicken carcasses. The cadF gene was present in nearly 100% of Campylobacter isolates tested, regardless of their origin or species. In contrast, the iam region was found in 83.3% and 100% of C. coli isolates from children and chickens, respectively, but in only 1.6% and 54.7%, respectively, of C. jejuni isolates. Similarly, the detection rates of cdt genes varied between human and chicken isolates. All three cdt genes were found in nearly all C. jejuni isolates from both children and chickens, but in only 5.6% of human C. coli isolates as compared to 87.2% of chicken C. coli isolates. This different distribution of genetic markers between human and chicken isolates indicates that some Campylobacter infections in children may have additional sources other than contaminated chicken meat.
    Preview · Article · Aug 2005 · Journal of Medical Microbiology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Previously found DNA sequence (iam), correlated with the invasiveness of Campylobacter strains, became a starting point for present investigation. Main goal of this study was to isolate number of Campylobacter strains from chicken carcasses, to determine their taxonomic position and to establish the presence of iam sequence in their genoms. It was found, that invasion associated marker is present in all Campylobacter coli strains and in majority but not all Campylobacter jejuni. This may confirm the idea that the marker is not only responsible for diarrhea in humans but also may be important in the colonization of chicken guts.
    No preview · Article · Feb 2004 · Roczniki Państwowego Zakładu Higieny
  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: Presence of anti-Helicobacter pylori(H. pylori) antibodies in the serum is a marker of persisting response to H. pylori infection but it is not indicative of active infection. Aim: The aim of the study was to assess the occurrence of active Helicobacter pylori infection in the group of H. pylori-seropositive children. Material and methods: The study comprised 96 children aged between 5 and 19 years with serum IgG anti-H. pylori antibodies. Gastrofiberoscopy was performed in all children and presence of H. pylori in the gastric mucosa was determined by three methods: the urea test (UT), histological examination of the mucosal biopsy specimens using Giemsa stain and in bacteriological cultures of the tissue specimens. Results: As a result of the performed studies we found: positive UT in 58 (60.4%) children, spiral forms of H. pylori on histological examination in 53(55.2%) and positive microbiological cultures in 57 (59.4%) of the study children. Conclusions: 1. Active Helicobacter pylori infection was found in more than a half of children with serum IgG anti-H. pylori antibodies, which required eradicative treatment. 2. Diagnostic effectiveness of the applied methods is similar for each of them. 3. Urease test and histologic examination together are clinical methods in diagnosis H. pylori.
    No preview · Article · Jan 2003
  • [Show abstract] [Hide abstract]
    ABSTRACT: To assess the relationship between density determined by quantitative culture, status, and gastric histology in children. Children with clinical symptoms indicating pathology in the upper gastrointestinal tract were referred for endoscopy. From each child blood was taken for serology, and antral biopsies were obtained for quantitative culture of and histology. Histological assessment was performed according to the updated Sydney System. The status of cultured was determined by polymerase chain reaction (PCR) and serum IgG response to CagA by western blotting. Adequate antral biopsies were obtained from 41 children with positive cultures. CagA IgG antibodies were found in 27 patients (66%), 25 of whom were also positive by the PCR. Two children infected with + strains as determined by the PCR were CagA seronegative. Infection with + strains was associated with significantly higher activity of inflammation and denser bacterial colonization in the antrum compared to negative strains. No correlation was observed between the density of colonization and chronic antral inflammation. This study shows that infection of children with + strains of is associated with enhanced activity of antral inflammation and higher density of colonization. There is a good correlation between serum western blot and bacterial PCR positivity in determining status and a positive relationship between histology and quantitative culture in assessing density in paediatric patients.
    No preview · Article · Jan 2003 · European Journal of Gastroenterology & Hepatology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the primary, secondary and combined resistance to five antimicrobial agents of 2340 Helicobacter pylori isolates from 19 centers in 10 countries in eastern Europe. Data were available for centers in Bulgaria, Croatia, the Czech Republic, Estonia, Greece, Lithuania, Poland, Russia, Slovenia and Turkey. Susceptibility was tested by agar dilution (seven countries), E test (five countries) and disk diffusion (three countries) methods. Resistance breakpoints (mg/L) were: metronidazole 8, clarithromycin 1, amoxicillin 0.5, tetracycline 4, and ciprofloxacin 1 or 4 in most centers. Primary and post-treatment resistance was assessed in 2003 and 337 isolates respectively. Results for 282 children and 201 adults were compared. Primary resistance rates since 1998 were: metronidazole 37.9%, clarithromycin 9.5%, amoxicillin 0.9%, tetracycline 1.9%, ciprofloxacin 3.9%, and both metronidazole and clarithromycin 6.1%. Isolates from centers in Slovenia and Lithuania exhibited low resistance rates. Since 1998, amoxicillin resistance has been detected in the southeastern region. From 1996, metronidazole resistance increased significantly from 30.5% to 36.4%, while clarithromycin resistance increased slightly from 8.9% to 10.6%. In centers in Greece, Poland, and Bulgaria, the mean metronidazole resistance was slightly higher in adults than in children (39% versus 31.2%, P > 0.05); this trend was not found for clarithromycin or amoxicillin (P > 0.20). Post-treatment resistance rates exhibited wide variations. In eastern Europe, primary H. pylori resistance to metronidazole is considerable, and that to clarithromycin is similar to or slightly higher than that in western Europe. Resistance to amoxicillin, ciprofloxacin and tetracycline was detected in several centers. Primary and post-treatment resistance rates vary greatly between centers.
    Full-text · Article · Jul 2002 · Clinical Microbiology and Infection
  • [Show abstract] [Hide abstract]
    ABSTRACT: Helicobacter pylori resistance to antimicrobial agents is an important factor compromising the efficacy of treatment. Therefore the aims of our study were: to determine the prevalence of H. pylori resistance to clarithromycin, metronidazole, amoxycillin and tetracycline in children prior to eradication therapy, to compare different methods of susceptibility testing and to detect mutations responsible for clarithromycin resistance. During 1996-2000, 259 H. pylori strains were isolated from antral gastric biopsies. Susceptibility to antimicrobials was determined by the agar dilution method and the Etest. Mutations in the 23S rRNA gene associated with clarithromycin resistance were analysed by PCR-RFLP and direct sequencing. Overall, ninety-six strains (37%) were resistant to metronidazole, 50 strains (19.3%) were resistant to clarithromycin, and 20 strains (7.7%) were simultaneously resistant to both drugs. All cultured isolates were sensitive to amoxycillin and only one isolate (0.4%) was resistant to tetracycline. The agar dilution method and the Etest showed a perfect category correlation for clarithromycin and 4% discrepancies for metronidazole. Primary resistance to clarithromycin was mainly associated with an A2143G mutation in the 23S rRNA gene of H. pylori. The study highlights the high prevalence of H. pylori primary resistance to clarithromycin in Polish children, which implies a need for pretreatment susceptibility testing.
    No preview · Article · Feb 2002 · Acta microbiologica Polonica
  • [Show abstract] [Hide abstract]
    ABSTRACT: Helicobacter pylori resistance to clarithromycin is an important factor in the failure of eradication therapy. The resistance results from point mutations in the 23S rRNA gene of H. pylori. The prevalence of primary resistance of H. pylori to clarithromycin in children and mutations associated with resistance were studied and it was found that 23.5% (23/98) of H. pylori strains isolated in our hospital during 1998-2000 were resistant to clarithromycin. The primary resistance was mainly caused by an A2143G mutation, but the isolates with an A2142G mutation had higher MICs for clarithromycin compared with those with an A2143G mutation: median MIC 256 versus 16 mg/l. Comparison of our data with previous results showed that the prevalence of H. pylori resistance to clarithromycin in children has increased in Poland over the last three years, however the difference was not significant (23.5 vs. 17%, P=0.22).
    No preview · Article · Nov 2001 · International Journal of Antimicrobial Agents
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Three Campylobacter jejuni 72Dz/92 genes (cjaA (ompH1), cjaC (hisJ) and cjaD (omp18)) encoding immunodominant proteins are considered to be potential chicken vaccine candidates. The presence and conservation of cjaA, cjaC and cjaD genes among different Campylobacter clinical isolates were determined. The genes were detected in thirty Campylobacter strains using hybridization as well as Western blot analysis. However, PCR products of the predicted size were amplified only from ten out of thirty examined strains regardless of the employed primer pair. The nucleotide sequence of the C. jejuni 72Dz/92 genes was compared with the nucleotide sequences of their homologs cloned from other Campylobacter strains as well as with the whole genome sequence of C. jejuni NCTC 11168. The examined sequences revealed 0 to 16% divergence. Strain-dependent levels of divergence were observed. The polymorphism detected in cjaC was mainly within the 5' region of the gene, while the nucleotide substitutions in cjaA and cjaD are distributed uniformly along the whole genes. Most of the observed nucleotide substitutions occurred at the third base of the codons. This observation is consistent with the results of Western blot experiments.
    Full-text · Article · May 2000 · FEMS Microbiology Letters
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Infection and associated disease caused by Helicobacter pylori are common in Poland, as in much of Eastern Europe, although the genotypes of strains have not been much studied, especially in terms of traits that might be important in disease. This study developed a sensitive and efficient polymerase chain reaction (PCR) test for the presence of H. pylori in gastric biopsy samples with ureA gene-specific primers and primers for the virulence-associated cag pathogenicity island (PAI). These tests were used with biopsy samples from 246 symptomatic children (age range 1-17 years) and 82 adults (age range 18-53 years) in Warsaw. An assessment was also made of the success of metronidazole-based therapy intended to eradicate infection. H. pylori was detected by ureA-specific PCR in 83 (76.9%) children and in 41 (87.2%) adults with histologically proven gastritis, and in 28.4% and 29.2%, respectively, of the 38 children and 7 adults with little or no evidence of gastritis. In general, H. pylori was detected more often by PCR than by culture (70.3% compared with 52.8% in children and 62.8% compared with 38.6% in adults), although in several cases a negative PCR was associated with a positive culture result. The rate of H. pylori infection increased with age from 5.4% in children up to 5 years old to 29.2% to age 10 and 65.4% to age 18. The tests detected the cagPAI in 97 (75%) and 44 (85%) of the H. pylori-infected children and adults, respectively. Some H. pylori-infected patients with a ureA+ PCR result contained the 'empty site' of the cagPAI and only four patients were infected with mixed cag+ cag- strains. PCR with cagPAI and 'empty site' of the cagPAI represents a novel tool for fast screening of mixed cag+ cag- infection. These results confirm and further illustrate that direct PCR of biopsy specimens can be useful for detection of infection and genotyping of resident strains, and that H. pylori infection is very common among children as well as adults in Poland. They also show that Polish strains vary with regard to the presence or absence of the cagPAI, and suggest that the proportion of strains that are cag+ is higher in Poland than in Western European countries, which may reflect the relatively higher risk of infection in this society.
    Full-text · Article · May 1999 · Journal of Medical Microbiology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Here we have studied the genetic diversity of Helicobacter pylori strains recovered from 64 individual patients, 5 family members and 13 unsuccessfully treated patients. The recovered bacteria were finger-printed by the PCR-RFLP and RAPD methods and virulence associated loci (cagPAI, vacA) were PCR studied. Unique differentiation of every independently isolated strain from not-related persons was possible by RAPD technique. In PCR-RFLP technique several profile groups (7 and 15) for particular endonuclease tested were found. Eleven patients carried strains of the same gene profile (PCR-RFLP) and the same overall genotype (RAPD) before and after therapy. In the family studies, essentially the same strain was found in different relatives in three cases, and different strains were found in the other two cases. Island of cagPAI was present in 79% of all strains tested, half and one-fifth of all strains tested presented, s1am2 and s1m1 alleles of vacA gene, respectively. Independently from identity or diversity of pre- and post-treatment strains and strains recovered from the family members we have been observed identical cagPAI/vacA genotypes. These results suggest that H. pylori infections in Poland can be mixed, although just one strain may often predominate, and that inter-family transmission may be significant even in this high risk society. The genetic feature of virulence-associated loci are similar to those seen elsewhere in Europe, although strains that carry the cagPAI and the potentially more toxigenic alleles of the vacA gene are more common. RAPD technique is proven as most differentiating, however PCR-RFLP allows for easy recognition of mixed infection with two or more different strains. Molecular typing study in case of children therapy may allow reduce rate of relapses by reduction of possible transmission from family source.
    Full-text · Article · Feb 1999 · Acta microbiologica Polonica

  • No preview · Article · Jan 1998 · European Journal of Clinical Microbiology

  • No preview · Article · Nov 1997 · European Journal of Clinical Microbiology

Publication Stats

405 Citations
45.73 Total Impact Points

Institutions

  • 1996-2009
    • Children's Memorial Health Institute
      • Department of Medical Genetics
      Warszawa, Masovian Voivodeship, Poland
  • 1996-2000
    • Centro Nacional De Investigaciones En Salud Materno Infantil (Cenismi)
      Santo Domingo Pueblo, New Mexico, United States
  • 1997
    • University of Warsaw
      • Institute of Microbiology
      Warsaw, Masovian Voivodeship, Poland