Significance of Screening Tests and the Incidence of New Delhi Metallo-beta-lactamase-Producing Gram-negative Bacilli in the Surgery and Transplantation Wards of a Warsaw Medical Center During the Period From April 2014 to May 2017.

BACKGROUND: The first New Delhi metallo-beta-lactamase (NDM)-producing bacteria were isolated in 2008 in the world, and in 2011 in Poland. Due to the high clonal diversity (17 types) of their blaNDM gene, encoded on (Tn125-like) mobile genetic elements, these strains usually exhibit resistance to nearly all available antibiotics, which is particularly dangerous for organ transplant recipients. PURPOSE: To assess of the prevalence of Gram-negative NDM-positive bacilli in surgery/transplantation wards of a teaching hospital in Warsaw and to ascertain the significance of screening tests on the rates and nature of colonization. MATERIALS AND METHODS: The evaluated strains were isolated from 30 patients (between April 2014 and May 2017). The species were identified with VITEK-MS, antibiotic susceptibility was determined with VITEK 2, disk-diffusion, and/or E-test methods, according to EUCAST guidelines. The presence of the blaNDM-1 gene was confirmed using the polymerase chain reaction technique. RESULTS AND CONCLUSIONS: There were 77 blaNDM-1-positive Klebsiella pneumoniae strains isolated from 30 patients. Cultures from individual patients, mainly from rectal swabs (53.9%) and urine samples (39.8%), yielded 1-11 isolates. Fifteen patients were already colonized on admission, and the other 15 developed a symptomatic infection. In total, 24 (80%) patients were carriers, and their colonizations persisted for <1-20 months. Most isolates were susceptible only to colistin, gentamicin, amikacin, tigecycline, and/or sulfamethoxazole/trimethoprim. Gastrointestinal-tract-colonizing K pneumoniae are the main reservoir of the blaNDM-1 gene. Following the introduction of on-admission mandatory screening for carbapenem-resistant strains, the rates of NDM-producing K pneumoniae isolation increased (7.5-fold), while the rates of isolation from patients with symptomatic infections considerably decreased (2.8-fold).

Surgical site infections in liver recipients in the early posttransplantation period: etiological agents and susceptibility profiles.

OBJECTIVE: This study evaluated the frequency of microbial isolates and their susceptibility profiles from cultures at the surgical site of 83 liver recipients in the early posttransplantation period. PATIENTS AND METHODS: We prospectively collected microbiologic culture data on 83 adult patients undergoing orthotopic liver transplantation (OLT) using standard procedures and commercially available tests. Susceptibility of the strains to antibacterial agents was performed by the Clinical and Laboratory Standards Institute (CLSI) guidelines. RESULTS: All patients were followed prospectively for the first 4 weeks after surgery. Among 284 microbial isolates from clinical surgical site samples in 80 liver recipients, cultures were positive in 110 samples. The most commonly isolated species were: Gram-positive cocci (n = 222 isolates, 78%) with dominance of methicillin-resistant coagulase-negative staphylococci (MRCNS; 42%) and high-level aminoglycoside-resistant enterococci (HLAR strains; 24.3%). Gram-negative bacteria were identified in 21.5% of positive cultures, including 30 strains (24%) from the Enterobacteriaceae family, with 13.3% of extended spectrum beta-lactamase producers [ESBL(+)]. Significant differences (P = .0012) were observed during the analysis of changes in the occurrence of Gram-positive bacteria isolated from the surgical site in the first week versus the second to the end of the fourth week. CONCLUSION: Gram-positive bacteria predominated as 78% of isolates.

Bacteria isolated from bile samples of liver recipients in the early period after transplantation: epidemiology and susceptibility of the bacterial strains.

OBJECTIVE: We estimated the frequency and susceptibility to antibacterial agents of bacterial isolates from bile samples obtained from 83 liver recipients in the early period after transplantation. PATIENTS AND METHODS: We prospectively collected data on 83 adult patients undergoing orthotopic liver transplantation (OLT), including bile samples taken during the first 30 days after OLT from adult liver recipients suspected to have bile infections. The isolation/identification of cultured bacteria was performed according to standard microbiological procedures and commercially available tests. Susceptibility of the strains to antibacterial agents was determined according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. RESULTS: Among 210 bile samples obtained from 79 liver recipients, bacterial cultures were positive in 110 samples from 59 (75%) recipients yielding 156 bacterial strains. The most commonly isolated species were as follows: gram-positive cocci (109 isolates) with dominance of coagulase-negative staphylococci (52%) and enterococci (36%); and gram-negative bacteria, 21 strains from the Enterobacteriaceae family and 14 of non-fermenting rods. We identified some multidrug-resistant (MDR) bacterial strains. In the first week after OLT, we investigated samples from 59 patients, yielding 36 bacterial strains. From the second to the end of the fourth week after OLT, 120 bacterial strains were isolated from 65 recipients. CONCLUSION: Gram-positive bacteria comprised 68.5%. The dominance of MDR gram-positive bacteria may be related to selection by perioperative antibiotic prophylaxis.

Detection of Clostridium difficile in stool samples from patients in the early period after liver transplantation.

OBJECTIVE: We examined the frequency of detection of Clostridium difficile (CD) toxins compared with the recovery of C. difficile in stool specimen cultures among orthotopic liver transplant (OLT) patients with nosocomial diarrhea in the early period. MATERIALS AND METHODS: The study included stool samples obtained during the first 30 days after OLT in adults who were suspected of CD-associated diseases. The identification of cultured CD strains was performed by standard microbiological methods. The presence of CD toxins was assayed using a commercial immunoassay. RESULTS: All patients were followed prospectively for CD infections from the date of OLT for the first 4 weeks after surgery. Among 54 samples, 16.7% were culture-positive for CD. CD toxins were tested on 54 samples, yielding 63% toxin-positive samples and 30% toxin- and culture-negative results. In the first week after OLT, samples from 19 patients were subjected to CD investigation. Among 19 samples positive for toxin, 52.6% of all samples were culture-negative. We analyzed 35 samples from the second to the fourth week after OLT in 31 recipients. Among 35 samples, 68.6% and 25.7% were positive for CD toxin and for culture, while 20% of samples were negative for toxin and culture. CONCLUSION: In our study, 63% of samples were toxin-positive with 16.7% yielding growth of CD and 30% being negative for toxins and cultures.

Etiological agents of bacteremia in the early period after liver transplantation.

Bacteremia is one of the major infections in orthotopic liver transplantation (OLT). The study of 83 adults who underwent OLT from 2001 to 2004, included patients followed prospectively from the day of transplantation to 4 weeks after the procedure by bacteriological cultures. The microorganisms were investigated according to standard National Committee for Clinical Laboratory Standards (NCCLS) procedures. Blood samples were examined in 59 recipients (71.1%) before and in 76 patients (91.6%) during the month after transplantation. Among 249 investigated samples, 96 were positive, as cultured from 19 recipients before OLT and 48 patients afterward. The most common were Gram-positive cocci (n = 71) and coagulase-negative staphylococci (n = 52), including methicillin-resistant coagulase-negative staphylococci (MRCNS). Enterococcus spp. occurred in 9 isolates (high-level aminoglycoside-resistant enterococci [HLAR] strains were cultured). We cultured the Enterobacteriaceae family (n = 16 isolates) and (n = 15 isolates), Gram-negative nonfermenting rods some of which were extended spectrum beta-lactamase producing [ESBL(+)] strains. The predominance of Gram-positive cocci was caused by CNS, and the use of prophylaxis to reduce Gram-negative bacteria. The increased rate of isolation of bacteria with multidrug resistance (MDR) to antimicrobial agents may be due to their frequent use for prophylaxis of bacterial infections in OLT. These MDR bacterial strains caused severe BSI after OLT.

Clinical glycopeptide-resistant enterococci isolated from patients after solid organ transplantation.

The aim of this study was to confirm the identification and resistance to vancomycin and teicoplanin of nosocomial enterococcal strains using molecular biology methods. Glycopeptide-resistant enterococci (GRE) strains were isolated from clinical specimens of hospitalized patients. Bacterial identification was performed in an automatic ATB Expression system (bioMérieux SA). Susceptibility to glycopeptides was determined by the disc diffusion method and Etest (AB BIODISK, Sweden). We performed polymerase chain reactions (PCR) for Enterococcus faecium and E. faecalis identification and van genes detection. Fifteen GRE strains were cultured over 2 years (2003-2004). Fourteen isolates were highly resistant to vancomycin (MIC range, 128->256 mg/L) and teicoplanin (MIC range, 32->256 mg/L). Twelve strains harbored van A gene (Van A phenotype). Seven isolates were identified as E. faecium and seven as E. faecalis by the multiplex-PCR method. One strain-E. casseliflavus-showed low resistance to vancomycin (MIC 8 mg/L) with retained susceptibility to teicoplanin (MIC 4 mg/L). It harbored the van C2/C3 gene and was identified as the Van C2/C3 phenotype. GRE strains were more often isolated from hospitalized patients in Poland. Constant monitoring by reliable microbiological methods has become necessary to prevent the spread of these strains in the hospital environment.

Drug Susceptibility Assessment in Stenotrophomonas Maltophilia Strains Isolated From the Blood of Organ Transplantation Recipients in a Warsaw Teaching Hospital During 2011 to 2014.

BACKGROUND: Blood infections with multidrug-resistant Gram-negative carbapenem-resistant bacilli are particularly dangerous and challenging to treat in organ transplant recipients. Resistance to carbapenems may be acquired, for example, in Enterobacteriaceae, Pseudomonas, or Acinetobacter spp. or innate, for example, in Stenotrophomonas maltophilia. The purpose of this study was to analyze blood infections caused by S maltophilia in organ transplant recipients and to compare drug susceptibility of these bacteria and the same species isolated from the blood of other inpatients. METHODS: A total of 26 S maltophilia strains isolated from blood samples of 26 patients (including 14 liver or kidney transplant recipients) hospitalized during 2011 to 2014 were evaluated in this study. Antibiotic susceptibility was determined via E-test and disk diffusion methods. RESULTS: Stenotrophomonas maltophilia strains isolated from blood exhibited sensitivity to trimethoprim/sulfamethoxazole (100%), levofloxacin (96.2%), ciprofloxacin (92.3%), ticarcillin/clavulanic acid (80.8%), and ceftazidime (53.9%). CONCLUSIONS: Because appropriate antibiotic therapy in the case of S maltophilia differs from the standard empirical therapy administered in the case of most other Gram-negative bacilli, early identification of this pathogen is of particular significance. The use of antibiotics to which this pathogen is sensitive eliminates the infection and helps avoid graft loss.

[Occurrence of extended spectrum beta-lactamases (ESBL) and inducible beta-lactamases (IBL) in clinical strains of gram-negative rods]. / Wystepowanie beta-laktamaz o rozszerzonym spektrum substratowym (ESBL) i beta-laktamaz indukowanych (IBL) u klinicznych szczepów paleczek Gram-ujemnych.

This study was undertaken to check the situation concerning the occurrence of Gram-negative rods producing extended-spectrum beta-lactamases (ESBL) and inducible beta-lactamases (IBL) in clinical specimens from patients hospitalized in National Clinical Hospital No. 1 in Warsaw. Such determinations were not performed in this hospital so far. During three months (April-June, 1997) 200 strains of Gram-negative rods were cultured. The strains were identified in automatic ATB system using strips with biochemical tests: ID 32 E for enteric rods and ID 32 GN for non-fermenting rods. ESBL-producing strains were detected with double disc diffusion test according to Jarlier et al. (1988). Clavulanate was applied as the inhibitor of beta-lactamases (AMO/CLAV disc). Inducible beta-lactamases were determined using double disc method according to Sanders and Sanders (1979). Cefoxitin was the inductor of these beta-lactamases. 82 strains (41% of all strains) belonging to Enterobacteriaceae family, 92 strains (46%) of Pseudomonadaceae rods and 26 strains (13%) of other Gram-negative rods were isolated. 30 ESBL-producing strains (15% of all strains) and 45 strains (22.5%) with IBL activity were detected. The obtained results confirm the necessity of continuous and reliable monitoring of ESBL--and IBL--producing strains among Gram-negative rods isolated from clinical materials. The aims of such procedure are the control and prevention of their dissemination within a hospital as well as the avoidance of therapeutic failures.

[Susceptibility of clinical strains of gram-positive bacteria to selected beta-lactam antibiotics]. / Wrazliwosc klinicznych szczepów bakterii gram-dodatnich na wybrane antybiotyki beta-laktamowe.

The aim of the study was to determine the activity of four beta-lactam antibiotics against nosocomial strains of Gram-positive bacteria. Two antibiotics combined with beta-lactamase inhibitors: timentin (TIC/CLAV) and tazocin (PIP/TZB) and two carbapenems: imipenem and meropenem were applied. The clinical strains were isolated from patients hospitalized in surgical ward of the National Clinical Hospital No 1 in Warsaw. The strains were identified in the automatic ATB system using ID 32 STAPH, API STREP, API CORYNE and API 20 A strips. The susceptibility of isolates to antibacterial agents was determined in the automatic ATB system using ATB STAPH, ATB STREP and ATB ANA strips. The susceptibility of strains to timentin, tazocin, imipenem and meropenem was tested with disc diffusion method. 111 strains of Gram-positive bacteria were cultured. Staphylococci (49) and enterococci (44) dominated among isolated strains. 33 Staphylococcus spp. strains were identified as methicillin-resistant. The obtained results indicate a significant role of Gram-positive cocci (staphylococci and enterococci) in the aetiology of nosocomial infections. Antibiotics combined with beta-lactamase inhibitors and carbapenems demonstrate broad antibacterial spectrum against clinical strains of Gram-positive bacteria except E. faecium strains.

[Susceptibility of clinical strains of gram-negative rods to selected beta-lactam antibiotics]. / Wrazliwosc klinicznych szczepów paleczek gram-ujemnych na wybrane antybiotyki beta-laktamowe.

The aim of the study was to determine the activity of four beta-lactam antibiotics against nosocomial strains of gram-negative bacilli. Two antibiotics combined with beta-lactamase inhibitors: timentin (TIC/CLAV) and tazocin (PIP/TZB) and two carbapenems: imipenem and meropenem were applied. The clinical strains were isolated from patients hospitalized in the following wards: surgery and intensive care unit of State Clinical Hospital No 1 in Warsaw. The strains were identified in the automatic ATB system using ID 32 E and ID 32 GN strips. The susceptibility of isolates to antibacterial agents was determined in the automatic ATB system using ATB G- and ATB PSE strips. The susceptibility of the strains to imipenem, meropenem, timentin and tazocin was tested by disc-diffusion method. 157 strains of gram-negative bacilli were cultured. 100 strains were isolated from patients hospitalized in surgical ward and 57 strains from patients hospitalized in ICU. Nonfermenting rods dominated among isolated strains-91. The results obtained indicate that multiresistant gram-negative rods causing serious therapeutic problems are often isolated from clinical specimens. The contribution of nonfermenting rods, especially Pseudomonas spp. and Acinetobacter spp. to the etiology of infections in hospitalized patients has increased. Infections caused by these strains are difficult to cure. Tazocin and carbapenems (imipenem and meropenem) are highly active in vitro against the examined strains of gram-negative bacilli.

[Drug resistance of 100 clinical strains of Enterococcus spp]. / Lekowrazliwosc 100 klinicznych szczepów Enterococcus spp.

The aim of this study was to evaluate the drug susceptibility of 100 Enterococcus spp. strains isolated from patients hospitalized in State Clinical Hospital No 1 in Warsaw. All strains were identified (API 20 STREP) and their susceptibility to antibiotics was tested (ATB STREP) in automatic ATB system. Additionally, PYRase activity, beta-lactamase production (in nitrocefin test), MICs for vancomycin and teicoplanin (E test), HLAR--high level aminoglycoside resistance and susceptibility to vancomycin, teicoplanin, piperacillin and piperacillin/tazobactam (disc diffusion method) were determined. E. faecalis ATCC 29212 was used as the control strain. Fifty E. faecalis, 45 E. faecium, 2 E. casseliflavus, 2 E. durans and 1 E. avium strain were cultured. All strains were PYRase-positive and beta-lactamase-negative. Ten isolates demonstrated intermediate susceptibility to vancomycin (6--E. faecalis and 4--E. faecium). One E. faecalis strain was intermediately susceptible to both glycopeptides. One E. casseliflavus strain showed low-level resistance to vancomycin, but this strain was susceptible to teicoplanin--phenotype Van C. HLAR strains were found among 31 E. faecalis and 40 E. faecium strains. 48 E. faecalis strains were susceptible to piperacillin and 49 to piperacillin/tazobactam. Whereas, 41 E. faecium were resistant to both these drugs. Thirty six per cent of isolates were resistant to penicillin and ampicillin, 73% to erythromycin, 87% to tetracycline, 89% to lincomycin and 56% to nitrofurantoin. Some discrepancies were noticed between the results of different methods applied for susceptibility testing--ATB system, E test and disc diffusion. These discrepancies concerned HLAR detection and susceptibility to glycopeptides determination. The best methods were: disc-diffusion for HLAR detection and E test for determination of resistance to vancomycin and teicoplanin. Increasing resistance to antimicrobial agents is observed in clinical Enterococcus spp. isolates cultured in our laboratory, especially in E. faecium strains. It is necessary to control the dissemination of multiresistant Enterococcus spp. strains in hospital wards.

[Drug resistance in nosocomial strains of staphylococci to methicillin]. / Lekowrazliwosc szpitalnych szczepów gronkowców metycylinoopornych.

The aim of the present study was the analysis of drug susceptibility of MRSA and MRCNS strains isolated from patients hospitalized in 14 wards of the State Clinical Hospital No 1 in Warsaw. The strains were identified (ID 32 STAPH), and their susceptibility to antimicrobial agents (ATB STAPH) was determined in ATB system (bioMérieux, France). Four methods were applied to confirm the resistance to methicillin: ATB-plus system, disc-diffusion method (Oxa 1 microgram, Oxoid, U.K.), Crystal MRSA ID (Becton Dickinson-BBL, USA) and agar screen test in TSA medium (Difco, USA) with methicillin (25 mg/l, Sigma, USA). 108 Staphylococcus spp. strains were found in 300 clinical specimens. 56 strains were methicillin-resistant (52%). Among methicillin-resistant strains 13 MRSA, 28 MRSE and 15 of other species were found. All MRSA strains were susceptible to vancomycin, teicoplanin and fusidic acid. MRCNS were susceptible first of all to vancomycin (43/43), minocycline (42/43) and pristinamycin (42/43). On the basis of the obtained results it can be stated that methicillin-resistant staphylococci occur in hospital wards. The greatest number of methicillin-resistant strains was cultured from patients hospitalized in surgery wards (32), methicillin-resistant strains much more frequently occur among coagulase-negative staphylococci, especially in Staphylococcus epidermis. Glycopeptide antibiotics are most active against isolated MRSA strains. The most active therapeutic agent against MRCNS is vancomycin.

[Comparison of several methods for detection of methicillin resistance in clinical strains of Staphylococcus sp]. / Porównanie kilku metod oznaczania opornosci na metycyline klinicznych szczepów Staphylococcus sp.

108 Staphylococcus spp. strains from 300 clinical specimens from hospitalized patients were isolated. Identification and drug resistance were determined using automated ATB system. 37 S. aureus strains, 44 S. epidermides strains and 27 strains of other coagulase-negative staphylococci were cultured. Sensitivity to methicillin of S. aureus was determined with four methods: ATB system, disc-diffusion (Oxa 1 microgram), Crystal MRSA ID System and agar screen test in TSA medium with methicillin (25 micrograms/ml). 13 S. aureus strains (about 1/3 of strains) were methicillin-resistant (MRSA). Complete conformity of the results was obtained with Crystal MRSA ID, disc-diffusion and agar screen tests. In the case of three S. aureus strains the results of determination in ATB system were not consistent with the results obtained with the use of the methods mentioned above. Susceptibility to methicillin of 71 coagulase-negative strains (CNS) was determined using two methods at first: ATB and disc-diffusion. In the case of 25 methicillin-resistant strains identical results were obtained. For 20 coagulase-negative strains non-conformity with the results of these two methods was observed. As the decisive method, the agar screen test (TSA-MET) was applied. 18 of these 20 CNS strains were categorized as methicillin-resistant. Finally, 43 MRCNS (i.e. 60%) were detected among 71 coagulase-negative strains. The results of methicillin resistance determination of staphylococci in an automated system should be confirmed with a second test such as agar screen, disc-diffusion or Crystal MRSA ID System (in the case of S. aureus).

[Use of the Etest method for antimicrobial susceptibility testing of obligate anaerobes]. / Zastosowanie metody Etest do oznaczania lekowrazliwosci bakterii beztlenowych.

The aim of this study was to evaluate Etest usefulness for antimicrobial susceptibility testing of obligate anaerobes and to compare the activity of five antibacterial drugs against clinical strains of anaerobes. One hundred strains of obligate anaerobes were tested: 2 reference strains (B. fragilis ATCC 25285 and B. thetaiotaomicron ATCC 29741) and 98 clinical strains isolated from patients of the Infant Jesus Clinical Hospital--Center for Trauma Treatment in Warsaw during the last three years (1997-1999). Strains of seven genera of obligate nonsporeforming anaerobes (Bacteroides, Prevotella, Porphyromonas, Fusobacterium, Peptostreptococcus, Propionibacterium and Actinomyces) and strains of two sporeforming species (C. perfringens and C. difficile) were examined. The MIC values were determined by the gradient diffusion method Etest (AB BIODISK, Sweden). Wilkins-Chalgren solid medium supplemented with 5% of sheep blood was used. Test plates were incubated at 35 degrees C for 48 hours in glove-box (85% N2, 10% H2, 5% CO2). The MIC values for each strain and antimicrobial agent, and the MIC ranges for bacteria of the same species were established. Ten strains resistant to clindamycin, ten resistant to piperacillin, and ten resistant to imipenem were detected. Seven strains were resistant to metronidazole and two strains to piperacillin combined with tazobactam. Tazobactam restored the susceptibility of eight strains to piperacillin. Obtained results confirm that Etest method is useful for antimicrobial susceptibility testing of obligate anaerobes. Older (clindamycin and metronidazole) and newer (piperacillin, piperacillin/tazobactam and imipenem) antimicrobial agents revealed high and comparable activity against clinical strains of obligate anaerobes. The percentage of strains susceptible to tested antimicrobials was > or = 90. These antimicrobials may be still useful in the empiric treatment of infections caused by medically important anaerobes.

[Evaluation of drug sensitivity and biochemical properties of coagulase-negative S. aureus strains isolated from clinical specimens]. / Ocena wrazliwosci na leki i cech biochemicznych u koagulazo-ujemnych szczepów S. aureus izolowanych z materialów klinicznych.

20-25% of strains isolated in our hospital in 1991 from clinical specimens and identified as S. aureus were coagulase-negative. These strains were characterized in respect of biochemical properties and resistance to antibacterial drugs. It was shown that the investigated group of strains displayed high drug resistance and particularly high percent of strains were resistant to methicillin (60%). 100% strains were resistant to penicillin and tetracyclines and most of them were resistant to aminocyclitol antibiotics. Coagulase-negative strains, in comparison with coagulase-positive, less frequently produced hemolysins and more frequently staphylokinase.

[Bacteriophages of serologic group A converting synthesis of staphylokinase and beta toxin in S. aureus]. / Bakteriofagi grupy serologicznej A konwertujace synteze stafylokinazy i toksyny beta u S. aureus.

The properties of the eight S. aureus bacteriophages of the serogroup A converting staphylokinase production were investigated. Three of them were able to a double conversion: production of the staphylokinase and inhibition of beta toxin synthesis. All of the investigated bacteriophages were classified as the I morphological group of the Styloviridae on the basis of the electron microscope analysis. The size of capsids of the examined bacteriophages was 77 +/- 2.8 nm x 43.1 +/- 1.9 nm and the tail length was 272.7 +/- 12.7 nm. Most of them (6 bacteriophages) had the tail terminated in the basal plate. The lytic properties of the investigated bacteriophages were not identical. Seven of them showed features of the III and one of the V (miscellaneous) lytic group.

[Production of staphylokinase and hemolysin by coagulase-negative staphylococcus]. / Wytwarzanie stafylokinazy i hemolizyn przez gronkowce koagulazo-ujemne.

The ability to staphylokinase production by the representative of the six of fifteen investigated species of staphylococci was detected: S. epidermidis, S. lentus, S. sciuri, S. lugdunensis, S. xylosus and S. hominis. The frequency of occurrence of this feature was different among the investigated species. Relatively, the least frequently this feature was observed with S. epidermis (2.3%) and S. xylosus (8.3%) strains. This property most frequently occurred among S. lentus--all the examined strains of this species produced staphylokinase. The hemolysins synthesis was shown among 13 of 15 investigated coagulase-negative species of staphylococci. The only two species of the examined representatives did not produce any hemolysin: S. hyicus and S. schleiferi. Complete correlation between staphylokinase synthesis and the absence of beta-hemolysin production was observed among strains: S. lugdunensis and S. lentus as with the lysogenic S. aureus strains with the double converting phages.

[Microflora of periodontal pockets in advanced periodontitis]. / Mikroflora kieszonek dziaslowych w zaawansowanym zapaleniu przyzebia.

The aim of study was the evaluation of periodontal pockets microflora in patients with advanced periodontitis. From each subject 16-20 samples were taken using paper points. Pooled sample after 60 s. mixing was serially diluted in reduced BHI. For total cell counts and for the isolation of black pigmented anaerobes Brucella agar supplemented with 5% sheep blood, hemin, menadione, with and without Kanamycin-Vancomycin mixture and BM agar plates were used. For isolation of A. actinomycetemcomitans TSBV agar plates were used. Cultures were incubated in anaerobic chamber at 37 degrees C for 7 days and TSBV agar plates in an atmosphere of 95% air-5% CO2 at 37 degrees C for 5 days. Microorganisms were identified by Gram staining, colony morphology, fluorescence in UV-light, haemagglutination of 3% sheep erythrocytes, fermentation of sugars, production of indole, urease (API 20A), specific enzymes (Rapid ID 32A). Twenty seven subjects with clinically recognized periodontitis were examined. Microorganisms important in periodontitis were isolated from periodontal pockets of almost all examined subjects. The number of bacteria obtained from the sample of one patient ranged from 1 x 10(4) CFU/ml to 3,6 x 10(6) CFU/ml. Porphyromonas gingivalis was identified in the samples taken from 17 patients, Prevotella intermedia-19, Actinobacillus actinomycetemcomitans -11, Fusobacterium nucleatum-9, Peptostreptococcus spp.-22.

[Beta-lactamases with a wide substrate spectrum in gram negative strictly anaerobic rods]. / Beta-laktamazy o rozszerzonym spektrum substratowym u Gram-ujemnych paleczek rosnacych w warunkach bezwzglednie beztlenowych.

This study was performed to determine the susceptibility of the clinical strains of Gram-negative strictly anaerobic rods to newer beta-lactam antibiotics. Also, the trial was undertaken to detect strains producing extended-spectrum beta-lactamases (ESBLs) and inducible beta-lactamases (IBLs) among Bacteroides spp. and Prevotella spp. rods isolated from hospitalized patients. One hundred strains of Gram-negative, obligatory anaerobic rods were applied in the study. The strains were identified in automatic ATB system using API 20 A strips. beta-lactamase-positive strains were determined with disc nitrocefin test. ESBL-producing strains were detected with double disc test according to Jarlier et al. (1988). Clavulanate was applied as the inhibitor of these beta-lactamases (AMO/CLAV disc). ESBL-positive strains were confirmed with the use of E test (TZ/TZL strip). Inducible beta-lactamases were determined by double disc method according to Sanders and Sanders (1979). Cefoxitin was the inducer of these beta-lactamases (FOX disc). Among 93 Bacteroides spp. strains and 7 Prevotella spp. strains, 91 strains (91%) produced beta-lactamases. Two ESBL-producing strains (2%) were detected. Strains producing inducible beta-lactamases (IBL) were not found. A high activity of the examined beta-lactam antibiotics against strains of Gram-negative anaerobes was found. The majority of strains were susceptible to piperacillin (95%), piperacillin combined with tazobactam (99%), ticarcillin combined with clavulanic acid (99%), meropenem (97%) and imipenem (99%). The obtained results indicate the necessity of ESBL determination among strains of the genus Bacteroides, isolated from clinical specimens. Newer beta-lactam antibiotics, especially penicillins in combination with beta-lactamase inhibitors and carbapenems, are useful in empiric therapy of infections caused by Bacteroides spp. and Prevotella spp. anaerobic rods.

[Etiologic agents of fungemia in hospitalized patients]. / Etiologiczne czynniki fungemii u hospitalizowanych pacjentów.

The aim of performed examinations was the analysis of fungi as etiological agents of blood infections in patients hospitalized in surgical wards, internal medicine wards and intensive care units of the Medical Academy Central Clinical Hospital in Warsaw. Blood samples from patients hospitalized in 1997 were examined. Peripheral blood samples were incubated in BacT/Alert system (Organon Teknika, USA). Positive blood samples were inoculated on Sabouraud medium with chloramphenicol (bioMerieux, France or Oxoid, England). The time of cultivation was from 48 hours to 7 days at 30 degrees C. Fungal strains were identified by standard mycological procedures with the use of chromogenic medium BBL CHROMagar Candida (Becton Dickinson, USA) and biochemical test ID 32 C (bioMerieux, France). Susceptibility of strains to antifungal agents was determined by ATB FUNGUS method (bioMerieux, France). The total number of positive blood cultures in 1997 was 1380. Forty-two fungal strains were isolated from blood samples (3%). Strains belonged to the following species: C. albicans (17 isolates), C. parapsilosis (15), C. glabrata (3), melibiosica (2), C. pelliculosa (2), C. guilliermondii (1), C. tropicalis (1) and T. beigelii (1). Among fungi cultured from patients hospitalized in operative wards dominated C. parapsilosis (11) and C. albicans (10) strains, whereas from patients hospitalized in conservative wards most often C. albicans (6) strains were isolated. Candida strains were mostly susceptible to antifungal agents tested. It was interesting to culture Trichosporon beigelii (T. cutaneum) strain as an etiological agent of fungemia. This strain was multidrug-resistant.