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.

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.

Fifty one episodes of bacteremia due to Enterobacter spp. appearing within 7 years among 12 301 admissions in a single cancer institution were studied for risk factors, clinical presentation and outcome. Fifteen episodes were due to Enterobacter aerogenes, 23 due to E. cloacae and 13 due to E. agglomerans. The proportion of bacteremia due to Enterobacter spp. among Gram-negative bacteremias was 10.1% and infection associated mortality was 13.8%. The incidence in 1989-1995 varied from 3.7 to 8.7% and was relatively stable. Most common risk factors were: solid tumors as underlying disease, central venous catheter insertion, prior surgery and prior chemotherapy within 48 h. Neutropenia and urinary catheters were not at high risk in either one of the patients subgroups. Comparing two subgroups of 51 bacteremias, monomicrobial and polymicrobial (when Enterobacter spp. was isolated from blood culture with other microorganism), previous chemotherapy, vascular catheter insertion and prior endoscopy were more frequently associated with polymicrobial Enterobacter spp. bacteremia. There was also differences in infection associated mortality: bacteremias due to Enterobacter spp. only had significantly lower mortality in comparison to polymicrobial Enterobacter spp. bacteremias (3.3 vs. 29.3%; P<0.02). Susceptibility of Enterobacter spp. strains isolated from 51 episodes was stable and showed only two episodes due to quinolone-resistant strains, both in 1992 despite of the use of ofloxacin in prophylaxis of neutropenic patients since 1990 in our institute. Ninety-two to 94% of all strains were susceptible to aminoglycosides, 96-98% to ofloxacin and ciprofloxacin, respectively and 94.9% to meropenem but only 75.5% to ceftazidime.

The resistance pattern of 2 816 isolates from 17 631 blood cultures and the etiology of isolates causing bacteremia and fungemia among 14 591 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%).

One hundred and twenty-three breakthrough bacteraemias (BB) were defined during a 5-year period in a National Cancer Centre, among 9986 admissions and a total of 979 bacteraemic episodes analysed, Of 123 bacteraemias in 103 patients, 77 were polymicrobial and 116 of the 323 organisms isolated were resistant to currently administered antimicrobial agents, Sixty-seven of the bacteraemic episodes were catheter-associated, as confirmed by the isolation of the same organisms from both blood and catheter tip. The strains isolated most frequently were coagulase-negative staphylococci (30.5%), corynebacteria (10%), Pseudomonas aeruginosa (10%), Enterococcus faecalis (9%) and viridans streptococci (8.5%), Gram-positive aerobes accounted for two-thirds of all micro-organisms isolated during breakthrough bacteraemic and fungaemic episodes, Polymicrobial episodes were associated more frequently with vascular catheters and neutropenia, and had a less favourable outcome than monomicrobial infections, Relapse was associated more frequently with catheter-related episodes, but the overall mortality, rate was similar and independent of catheter insertion, Breakthrough bacteraemic and fungaemic episodes were associated more frequently with acute leukaemia, Catheter removal, as an independent variable, and modification of antimicrobial therapy were essential for better outcome.

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%).

Fifty cancer patients with funguria of >105 CFU/ml, dysuria and leukocyturia were retrospectively analyzed for etiology, risk factors and outcome. In 72% of casesCandida albicans and in 28% non-albicansCandida spp. (Candida krusei, Candida tropicalis) and non-Candida spp. yeasts (Blastoschizomyces capitatus) were isolated.Torulopsis glabrata was not found among these patients. The most frequent risk factors were: antibiotic therapy with more than one antibiotic agent (96%), concomitant fungal infection in other localizations than the urinary tract (36%), colonization with the same species (48%), catheterization with urinary catheter or nephrostomy (46%), prophylaxis with quinolones (50%) and previous therapy with corticosteroids (72%). Structural or anatomic malformations of the urinary tract (26%), neutropenia (28%), antifungal prophylaxis with azoles (22%), and diabetes mellitus (12%) were less frequently seen. Thirty of 36 patients treated with systemic antifungals were cured and six were not.

One hundred twenty three breakthrough bacteraemias (BB) during 5 years in a National Cancer Institute, among 9986 admissions and 979 bacteraemic episodes were analysed. 123 BB were caused by 323 microbes, only 116 were resistant (31.5%) to currently administered antimicrobials. Sixty seven of 123 bacteraemic episodes were catheter associated confirmed by isolation of the same organisms from the blood and catheter tip. 77/123 BE were polymicrobial. The most frequently isolated strains were coagulase negative staphylococci (30.5%), Corynebacteria (10%), Ps. aeruginosa (10%), Str. faecalis (9%) and Viridans streptococci (8.5%). Gram-positive aerobes accounted for two-thirds of all organisms isolated during breakthrough bacteraemic and fungaemic episodes. Mixed polymicrobial breakthrough bacteraemic and fungaemic episodes were more frequently associated with vascular catheter insertion and neutropenia, and had a less favourable outcome in comparison to monomicrobial infections. The relapse was associated more frequently with catheter related bacteraemic and fungaemic episodes, but the overall mortality rate was similar independently from catheter insertion. Breakthrough bacteraemic and fungaemic episodes were associated more frequently with acute leukaemia. Polymicrobial breakthrough bacteraemic and fungaemic episodes were associated more frequently in neutropenic episodes and in venous catheters. Regarding the outcome, an extraction of the catheter with no dependence on variable and modification of antimicrobial therapy were essential for the improvement in the prognosis. (Tab. 5, Ref. 20.).

Thirty one bacteremic episodes (BE) in 31 patients due to anaerobic bacteremia (AB) in 979 BE among 9986 admissions at a 360 beds National Cancer Institute within last 6 years were analyzed for time distribution, risk factors, clinical presentation and outcome. Overall incidence of AB was 3.6%, but the proportion to other groups of microorganisms is decreasing. 73% were Bacteroides fragilis, 10.8% Peptostreptococci and Propionibacteria and 5.4% Clostridia. The most common risk factor for AB was prior surgery, solid tumor as underlying disease, prophylaxis with quinolones and previous therapy with third generation cephalosporines. 48.4% of AB were polymicrobial. Infected wound was the most common source of infection in 38.7% of our cancer patients. Six patients (19.4%) presented septic shock, and 45.2% died, but only in 22.6% death was related to bacteremia. Comparing the groups of AB due to B. fragilis (BF) to non-Bacteroides spp. (NB)AB, infection-associated mortality was higher in BFAB in comparison to NBAB. Other risk factors such as hematologic malignancies, previous prophylaxis with quinolones, prior surgery and prior therapy with broad spectrum antimicrobials, were more frequently associated with BFAB.

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).

The authors analyzed 27 breakthrough bacteremias occurring during ofloxacin prophylaxis in afebrile neutropenia over 7 years in 9989 admissions and 979 bacteremic and fungemic episodes in a National Cancer Center in Bratislava, Slovak Republic. The most frequently isolated organisms in breakthrough bacteremias were gram-positive (71.3%), mainly coagulase-negative staphylococci (41.3%), enterococci (9.2%) and Corynebacteria (9.2%), followed by gram-negative rods - Pseudomonas aeruginosa (13.2%) and Stenotrophomonas maltophilia (9.2%). The outcome of breakthrough bacteremias during ofloxacin prophylaxis was not associated with the underlying disease, neutropenia, catheter insertion or resistance, but only with multiple risk factors. A higher failure rate was observed in those patients having a catheter infected with a resistant organism and during neutropenia. No patients with Hickman catheter were included in the study. Patients with mixed breakthrough bacteremia due to gram-negative and gram-positive organisms had higher failure rates than those with monomicrobial bacteremia. Catheter extraction and rapid institution of intravenous antibiotics in combination should be administered in breakthrough bacteremia.

The development of antimicrobial resistance in main pathogens of respiratory system infections (S. pneumoniae, H. Influenzae, B. catarrhalis) reduces the range of unprotected penicillins indications. The inhibitors of beta-lactamase rendered back the original spectrum of antimicrobial activity to aminopenicillins and ureidopenicillins, and withheld them within the most frequently used armamentarium of antimicrobial drugs for the therapy of more severe infections. The prescription of penicillins is ruled according to the localization of infection, most frequent pathogens and by the epidemiologic situation. A combined antibiotic therapy is indicated in severe infections. An important indication area is the prophylactic administration of penicillins in recurring tonsilopharyngitis, recurring otitis media and eradication of meningococcal carriership. (Tab. 1, Ref. 3.).

Ninety nine patients with 101 bacteraemic episodes due to Ps. aeruginosa (PA) within 6 years were divided into two groups according to their resistance to imipenem-91 due to imipenem sensitive (ISPA) and 10 due to resistant (IRPA). Risk factors, the clinical course and the outcome were evaluated and compared. Acute leukaemia, prolonged neutropenia, previous therapy with amikacin, third generation of cephalosporins, imipenem and prophylaxis by quinolones were significantly more frequently associated with IRPA. Imipenem resistant PA bacteraemia were associated with higher incidence of septic shock (40% vs 19.8%, p < 0.02) and death (33.3%) than ISPA bacteraemias. Since 1992, when first IRPA appeared, the incidence of imipenem resistance increased tenfold, and in 1994, up to 10% of PA causing bloodstream infections in cancer patients in our center were imipenem resistant. (Tab. 3, Ref. 8.).

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%).

137 patients with febrile neutropenia after cytotoxic therapy not responding to ceftazidime plus or ceftriaxone plus netilmicin in received additionally to the previous combination either vancomycin alone or combined with another anti-gram-negative compound: imipenem in those treated prophylactically with ofloxacin and ciprofloxacin in those without prophylaxis. The addition of vancomycin to the previously ineffective combination of a third generation cephalosporin plus aminoglycoside, and replacement of ceftriaxone plus netilmicin with ceftazidime plus amikacin plus vancomycin or with ceftazidime plus vancomycin seems to be less effective (71.8-75 vs. 87.5-90.9%, p < 0.02) and more toxic (20.5-7.2 vs. 0-5%, p < 0.0005) than vancomycin in combination with a different anti-gram-negative compound as previously used: imipenem or ciprofloxacin.