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Featured researches published by P. Koren.


Scandinavian Journal of Infectious Diseases | 1997

Viridans Streptococcal Bacteraemia Due to Penicillin-Resistant and Penicillin-Sensitive Streptococci: Analysis of Risk Factors and Outcome in 60 Patients from a Single Cancer Centre Before and After Penicillin is Used for Prophylaxis

S. Spanik; J. Trupl; A. Kunova; Rudolf Botek; Dagmar Sorkovska; E. Grey; Mariana Studena; J. Lacka; E. Oravcova; Adriana Krchnakova; Viera Rusnakova; Juraj Svec; Iveta Krupova; S. Grausova; Katarina Stopkova; P. Koren; V. Krcmery

60 patients with 60 viridans streptococcal bacteraemic episodes (42 due to penicillin-sensitive and 18 due to penicillin-resistant viridans streptococci) were analysed in a population of 12,185 admissions and 1,380 bacteraemic episodes during a 7-year period in a National Cancer Institute. The incidence of viridans streptococci among bacteraemias decreased from 11.5% in 1989 to 2.5% in 1995 after penicillin was introduced for prophylaxis of febrile neutropenia in acute leukaemia in 1993. However, the proportion of penicillin-resistant viridans streptococcal bacteraemias increased from 0 in 1989 and 1990 before any prophylaxis was given, to 12.9-16.7% after quinolones were used for prophylaxis in 1991 and 1992, and to 44.4-81.8% in 1993-1995 after penicillin was added to the quinolones. Mortality rate was higher in the subgroup of penicillin-resistant viridans streptococcal bacteraemias (p < 0.05). Statistically significant risk factors in patients with penicillin-resistant (compared with penicillin-sensitive) viridans streptococcal bacteraemia were: acute leukaemia (p < 0.03), high doses of cytarabine (p < 0.05), mucocutaneous lesions (p < 0.004), breakthrough bacteraemia during prophylaxis with ofloxacine plus penicillin (p < 0.001). Multiple logistic regression analysis showed that only acute leukaemia (OR 2.05, CI 0.85-1.85, p < 0.00452) and penicillin-resistance (OR 0.71, CI 0.103-4.887, p < 0.0209) were significant independent predictors of inferior outcome. Breakthrough bacteraemia during empiric therapy with vancomycine occurred in 5 of 116 patients treated with vancomycine, and during therapy with ampicillin plus gentamicin in 6 patients of 18 treated.


Diagnostic Microbiology and Infectious Disease | 1998

Etiology and Risk Factors of 180 Cases of Native Valve Endocarditis: Report from a 5-Year National Prospective Survey in Slovak Republic

V. Hricak; Juraj Kovacik; Peter Marx; Eva Schramekova; V. Fischer; Dana Vitekova; Tibor Sedlak; Ivan Duris; Jan Samudovsky; Maria Semanova; Milan Kovac; Tibor Duris; Oto Herman; Maria Cernoskova; Jan Sefara; Maria Kojsova; Dagmar Baranikova; Michael Ayazi; Jan Dacok; Marian Mraz; Stanislav Krizan; Jan Danaj; Anna Margareta Sulcava; Dagmar Neuschlova; Vladimir Milovsky; P. Koren; V. Krcmery

Risk factors, etiology, and outcome of 180 cases of infective endocarditis (IE) in the Slovak Republic for 5 years were prospectively studied in a national survey. According to the Duke Endocarditis Service Criteria (1994), 169 cases were considered definitive and 21 possible/probable. The aortic valve was infected in 46.7%, mitral in 47.2%, and tricuspidal/pulmonary in 6.1% of cases. The majority of endocarditis cases was caused by Staphylococcus aureus and coagulase-negative staphylococci (CNS) (33.3%); only 12.2% were due to viridans streptococci; 11.7% were due to Enterococcus faecalis; 6.1% due to Haemophilus spp.; 10.1% due to other organisms; and 26.7% were culture negative. Single positive cultures of CNS were not considered clinically significant. More than 25% of 180 patients were older than 60 years. Rheumatic fever was a risk factor in 35.5%, dental surgery in 20.5%, prior cardiosurgery in 7.8%, and neoplasia in 6.7%. All patients were treated with antimicrobials (average length of therapy was 29.5 days) and 33.3% of patients also had surgery (valvular prosthesis replacement). Forty (22.2%) died, and 140 (77.8%) survived at day 60 after the diagnosis of endocarditis was made. All 40 deaths were attributable to infection. Univariate analysis comparing deaths and survivors did not show significant differences in most of the recorded risk factors between both groups, except age > 60 (40.0% versus 21.4%, p < 0.05), staphylococcal etiology (55.0% versus 27.1%, p < 0.04), and antibiotic therapy < 21 days (without surgery) (65.0% versus 3.6%, p < 0.01). These risk factors were significantly more frequently associated with deaths. Viridans streptococcal IE and surgical therapy in addition to antibiotics were associated with lower mortality in comparison to staphylococcal endocarditis (p < 0.045) or to cases treated with antibiotics only (p < 0.05). In comparison to other nationally based surveys in Europe (Greece, Croatia, France), the percentage of culture-negative endocarditis and spectrum of pathogens differed significantly.


Scandinavian Journal of Infectious Diseases | 1997

Fungemia in cancer patients undergoing chemotherapy versus surgery: risk factors, etiology and outcome.

K. Kralovicová; S. Spanik; E. Oravcova; M. Mrazova; E. Morova; V. Gulikova; E. Kukuckova; P. Koren; P. Pichna; J. Nogova; A. Kunova; J. Trupl; V. Krcmery

26 patients with fungemia and cancer treated with chemotherapy (group A) were compared to 25 patients with fungemia and cancer treated with surgery (group B), to assess differences in etiology, risk factors and outcome. Candida albicans was responsible for 42% of fungemias in group A, and for 92% of fungemias in group B (p < 0.005). Breakthrough fungemia occurring during antifungal prophylaxis appeared in 46.6% of group A vs 12% of group B (p < 0.02). There was significant difference in outcome between the groups: 20% of patients after surgery vs 7.7% of those after chemotherapy died from fungemia (p < 0.04). Most common risk factors recorded in both groups were catheter insertion and previous therapy with broad spectrum antibiotics.


Supportive Care in Cancer | 1997

Analysis of 553 episodes of monomicrobial bacteraemia in cancer patients: any association between risk factors and outcome to particular pathogen?

S. Spanik; E. Kukuckova; P. Pichna; S. Grausova; I. Krupova; V. Rusnakova; K. Kralovicova; Adriana Krchnakova; M. Mrazova; J. Lacka; P. Koren; K. Stopkova; J. Nogova; A. Demitrovicova; L. Helpianska; V. Krcmery

Abstract Relationships between aetiology, various risk factors (such as neutropenia, catheter insertion, endoscopy, therapy with corticosteroids, therapeutic use of antimicrobials, antibiotic prophylaxis, source of infection), symptomatology and outcome were studied in 553 monomicrobial bacteraemic episodes in cancer patients observed within 7 years at the National Cancer Institute of the Slovak Republic. The ratio of gram-positive to gram-negative bacteraemia was 1:1 (43.5% vs 43.8%), and yeasts caused 7.2% of monomicrobial episodes. The highest mortality was associated with Pseudomonas aeruginosa (19.2%), non-albicans Candida yeasts (25%) and Bacteroides fragilis (22.6%). Independent risk factors for particular pathogens were investigated by a computerized logistic regression model. The only independent risk factor for staphylococcal and enterococcal bacteraemia was vascular catheter insertion (OR=1.95 and 2.05, CI=95%, P=0.035 and 0.044, respectively). However, there were no independent specific risk significant factors for viridans streptococcal bacteraemia and bacteraemia due to Enterobacteriaceae or Ps. aeruginosa. Neutropenia was found to be an independent predictor for development of Acinetobacter spp. bacteraemia (OR=3.84, CI=95%, P=0.044). Prior therapy with third-generation cephalosporines was a predictive, independent risk factor for the development of fungaemia (OR=1.99, CI=95%, P=0.028) but not of enterococcal bacteraemia. We also did not observe any association between prior therapy with imipenem and Stenotrophomonas maltophilia bacteraemias. Multivariate analysis confirmed that fungaemia may be independently associated with higher mortality than bacteraemia caused by Enterobacteriaceae and staphylococci. However, the mortality of fungaemia was statistically no different from that of Ps. aeruginosa, Stenotrophomonas spp. and viridans streptococci bacteraemias.


International Journal of Infectious Diseases | 2002

Bacteremias caused by Escherichia coli in cancer patients — analysis of 65 episodes

V. Krcmery; S. Spanik; M. Mrazova; J. Trupl; S. Grausova; E. Grey; E. Kukuckova; Margita Sulcova; Iveta Krupova; P. Koren

OBJECTIVES The aims of this study were to evaluate risk factors, clinical presentation, outcome and antimicrobial susceptibility in patients with Escherichia coli bacteremia occurring over seven years in a single cancer hospital. METHODS Sixty five episodes of bacteremia from E. coli appearing over seven years from 12,301 admissions in a single cancer institution were retrospectively analyzed. RESULTS The proportion of bacteremia caused by E. coli among Gram-negative bacteremia was 20.8% (the second most common organism after Pseudomonas aeruginosa), and infection-associated mortality was 17%. The incidence in 1989-1995 varied from 14.3 to 24.7%. The most common risk factors were: solid tumors as the underlying disease (70.7%); central venous catheter insertion (32.3%); prior surgery (46.2%), and prior chemotherapy within 48 h (44.4%). Neutropenia and urinary catheters did not place patients at high risk in any of the subgroups. When we compared the two subgroups of 61 cases of bacteremia - monomicrobial and polymicrobial (when E. coli was isolated from blood culture with another microorganism) - we found that acute leukemia and breakthrough (recurrence while receiving antibiotics) bacteremia were more frequently associated with polymicrobial E. coli bacteremia. There was also a difference in infection-associated mortality: monomicrobial bacteremia due to E. coli only had a significantly lower mortality in comparison with polymicrobial E. coli bacteremia (8.9 vs 35.0%, respectively; P<0.03). CONCLUSION The susceptibility of 115 E. coli strains isolated from 65 episodes of bacteremia was stable. Only two episodes caused by quinolone-resistant strains occurred, both in 1995, after six years of using ofloxacin for prophylaxis in neutropenic patients in our hospital. We found that 85.2-91.3% of all strains were susceptible to aminoglycosides, 97.8% to quinolones, and 90-100% to third generation cephalosporins and imipenems. The patients most commonly infected had solid tumors and the mortality was only 17%.


Acta Oncologica | 1997

Resistance Pattern of 2 816 Isolates Isolated from 17 631 Blood Cultures and Etiology of Bacteremia and Fungemia in a Single Cancer Institution

J. Trupl; A. Kunova; E. Oravcova; Peter Pichňa; E. Kukuckova; S. Grausova; E. Grey; S. Spanik; Andrea Demitrovióvá; K. Kralovicova; J. Lacka; Iveta Krupova; Juraj Svec; P. Koren; Vladimir Krčéry

The resistance pattern of 2816 isolates from 17631 blood cultures and the etiology of isolates causing bacteremia and fungemia among 14591 admissions were investigated in an 80-bed single cancer institute during seven years (1990-1996) under the same empiric therapeutic antibiotic policy but with different prophylactic strategies. No change was found in the proportion of Gram-positive versus Gram-negative bacteria isolated from bacteremias (70% vs. 30%) during the past seven years. Furthermore, the proportion of coagulase-negative staphylococci and enterococci was about the same before and after the introduction of ofloxacin in prophylaxis. However, the proportion of Pseudomonas aeruginosa and Stenotrophomonas maltophilia causing bacteremia increased. There was no increase in Candida krusei and Candida glabrata after the introduction of fluconazole into our prophylactic regimen in 1992. Penicillin-resistance in viridans streptococci increased after penicillin was introduced into prophylaxis in acute leukemia in 1993. Until 1995 no quinolone-resistant Enterobacteriaceae were observed. Susceptibility to quinolones did not significantly change within the past seven years in Enterobacteriaceae after their introduction to prophylaxis in 1991, but Pseudomonas aeruginosa decreased from 90 to 58.2%. Glycopeptide resistance in enterococci and staphylococci was minimal in the observed period (0.9-4.3%).


Supportive Care in Cancer | 1997

Postoperative bacteremia in cancer patients with solid tumors undergoing surgery: risk factors, etiology and outcome in 276 patients

S. Spanik; K. Stopkova; S. Grausova; P. Koren; J. Sepesi; V. Krcmery

Dear Editor, Ranchere et al., in one of the last issues of Supportive Care in Cancer [3], reported on 33 cancer patients who had undergone surgery and had bacteremia and compared them with 22 patients who were treated by chemotherapy only. They did not find a higher number of infections in the group receiving chemotherapy plus surgery. Chemotherapy did not seem to increase the incidence of infection [3]. We would like to add some more data to this interesting paper from our own experience on 48 patients with bacteremia after oncologic surgery. We have compared two groups of patients with solid tumors: 48 with postoperative bacteremia appearing 5 days after surgery only, and a control group of 172 patients treated with chemotherapy only. Patients treated with both surgery and chemotherapy were excluded. Both groups were selected during the last 7 years, 1989–1995, from among those treated at a single institution (National Cancer Institute) with similar antibiotic and prophylactic policies and were compared with the help of T-tests and Fisher’s exact T-test. P-values under ~0.05 were considered statistically significant. There was no difference between the two groups (48 treated with surgery only versus 172 with chemotherapy only) in underlying disease, localization of solid tumors, and some risk factors, such as diabetes mellitus, prior endoscopy, monomicrobial or polymicrobial bacteremia or total number of positive blood cultures (Table 1).


Supportive Care in Cancer | 1996

Staphylococcal bacteremia in cancer patients: Risk factors and outcome in 134 episodes prior to and after introduction of quinolones into infection prevention in neutropenia

E. Kukuckova; S. Spanik; I. Ilavska; L Helpianska; E Oravcova; J Lacka; I. Krupova; S. Grausova; P. Koren; I Bezakova; E Grey; M Balaz; M. Studena; A. Kunova; K Torfs; J. Trupl; S Korec; K. Stopkova; Krcmery

A total of 134 episodes of staphylococcal bacteremia (SBE) appearing among 9987 admissions, and 979 episodes of bacteremia in cancer patients within 5 years, were analyzed for risk factors, clinical course and outcome; 64 were monomicrobial and 70 polymicrobial. The most frequent risk factors were acute leukemia, catheter insertion, long-lasting neutropenia, and prior prophylaxis with quinolones. There was no significant difference between polymicrobial and monomicrobial SBE in risk factors. The two groups differed only in the source of bacteremia (gastrointestinal and respiratory-tract infections were more common in monomicrobial SBE) and etiology —Staphylococcus aureus appeared more frequently in monomicrobial than in polymicrobial bacteremia (20.3% compared to 4.3%,P<0.05). More complications (14.3%) such as abscesses, endocarditis, etc. appeared in the group of polymicrobial SBE (P < 0.05). No difference was observed in clinical course and outcome between monomicrobial and polymicrobial SBE. The incidence of SBE has increased since 1991, when quinolones were first used in prophylaxis in afebrile neutropenia at our center; however, the infection-associated mortality in monomicrobial SBE was low (4.3%).


Chemotherapy | 1996

Ofloxacin Once Daily versus Twice Daily in Community-Acquired Pneumonia and Acute Exacerbation of Chronic Bronchitis

Rayman J; M. Krchnavý; P. Balcior; J. Duchoň; J. Fortuník; L. Faith; Manduchova H; L. Drgona; P. Koren; Kraszko I; V. Krcmery

Eighty-two patients with community-acquired pneumonia (CAP) or acute exacerbation (AE) of chronic bronchitis were randomized to receive ofloxacin (OFL) 400 mg twice daily (39 patients) versus 400 mg once daily (43 patients) orally. Cure rates showed no statistically significant difference (90.1 vs. 94.6%), but more patients receiving 800 mg/day had side effects. Thus, the once daily administration of OFL is equally effective and safer than 400 mg twice daily to treat CAP or AE chronic obstructive pulmonary disease, especially in countries with higher pneumococcal and Haemophilus influenzae resistance in community practice.


International Journal of Antimicrobial Agents | 1996

Polymicrobial bacteremia in cancer patients : analysis of risk factors, etiology and outcome in 214 episodes

I. Ilavska; P. Pichna; K. Stopkova; S. Grausova; I. Krupova; E. Oravcova; P. Koren; J. Lacka; M. Studena; S. Spanik; A. Kunova; J. Trupl; V. Krcmery

Two hundred and fourteen episodes of polymicrobial bacteremia in 182 cancer patients in a period of 6 years in a 360-bed National Cancer Institute were analyzed for etiology, risk factors and outcome. Variables were compared with 187 episodes of monomicrobial bacteremias in 147 cancer patients to find statistical significance among risk factors, etiology and outcome. Urinary catheters and breakthrough bacteremia were the only risk factors associated with polymicrobial in comparison to monomicrobial bacteremia (P < 0.05). Concerning etiology, Enterococcus faecalis, Candida spp., Acinetobacter calcoaceticus and Stenotrophomonas maltophilia were more commonly isolated in polymicrobial than in monomicrobial bacteremic episodes. Polymicrobial bacteremia presented more frequently with septic shock (22.9% vs. 9.0%, P < 0.05) and/or organ complications (25.2% vs. 11.8%, P < 0.05). However, mortality due to bacteremia did not significantly differ between polymicrobial and monomicrobial, but when polymicrobial bacteremia with and without coagulase negative staphylococci were compared, mortality in polymicrobial bacteremia without staphylococci was higher (10% vs. 4.7%, P < 0.04).

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J. Trupl

University of Trnava

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J. Lacka

University of Trnava

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