In vitro biodegradation testing of Mg-alloy EZK400 and manufacturing of implant prototypes using PM (powder metallurgy) methods

The study is focussing towards Metal Injection Moulding (MIM) of Mg-alloys for biomedical implant applications. Especially the influence of the sintering processing necessary for the consolidation of the finished part is in focus of this study. In doing so, the chosen high strength EZK400 Mg-alloy powder material was sintered using different sintering support bottom plate materials to evaluate the possibility of iron impurity pick up during sintering. It can be shown that iron pick up took place from the steel bottom plate into the specimen. Despite the fact that a separating boron nitrite (BN) barrier layer was used and the Mg-Fe phase diagram is not predicting any significant solubility to each other. As a result of this study a new bottom plate material not harming the sintering and the biodegradation performance of the as sintered material, namely a carbon plate material, was found.

Urinary tract infections in the early posttransplant period after liver transplantation: etiologic agents and their susceptibility

BACKGROUND

We performed an analysis of etiologic agents for urinary tract infections in the early posttransplant period after orthotopic liver transplantation (OLT) in adult recipients.

PATIENTS AND METHODS

The study covered the first 4 weeks after OLT of 190 patients from September 2001 to the end of 2007. Immunosuppression consisted of steroids and tacrolimus. Antimicrobial prophylaxis was piperacillin/tazobactam, fluconazole, and SBD. Urine samples were cultured to identify microorganisms in accord with standard microbiological procedures and to test susceptibility using Clinical Laboratory and Standards Institute guidelines.

RESULTS

Urine specimens (n=539) examined from 185 recipients (97.4%) showed 210 microbial strains. The most common were Gram-negative (n=131; 62.4%) with predominance of Escherichia coli (28.2%), Enterobacter cloacae (19.1%), and Acinetobacter baumannii (11.4%). Extended-spectrum β- lactamases (ESBL(+)) strains were isolated in 38.5% of cases. Gram-positive bacteria comprised 28.6% (n=60): The most common strains were enterococci (85% including HLAR 80.4% and VRE 17.6%] and staphylococci 11.8% [MRSA/MRCNS; 100%]. There were 19 (9%) fungal strains.

CONCLUSIONS

In general, the identification in urine samples of multi-drug-resistant bacterial and fungal strains in patients after OLT such as ESBL(+) 38.5%; HLAR 80.4%; VRE 17.6%; and MRSA/MRCNS 100% requires better infection control.

[Frequency of detection of human herpesvirus type 6 DNA in patients of Public Independent Central Hospital in Warsaw in years 2003-2007]

Human herpesvirus 6 (HHV-6) has been recognized as a potential significant pathogen in haemopoietic stem cell transplant recipients. Different clinical manifestations have been described including fever, skin rash, bone marrow suppression and encephalitis. The aim of the study was to show frequency of presence of human herpesvirus type 6 DNA in patients of Public Independent Central Clinical Hospital in Warsaw in years 2003-2007. 1357 clinical samples taken from 71 a group of adult recipients of allogeneic HSCT were tested for the presence of HHV-6 DNA using the quantitative in-house real-time PCR assay. Positive results were obtained in 12.5% of all examinations made during described period and also in 35.2% of investigated patients. All of them developed fever of unknown origin, and over 50% had GvHD features. Nine individuals from this group died during detectable HHV-6 viremia.

Prevalence of human herpesvirus 6 antibodies and DNA in allogeneic stem cell transplant patients: two-year single centre experience

Introduction:

Human herpesvirus 6 (HHV-6) has been recognized as a potentially significant pathogen in hemopoietic stem cell transplant (HSCT) recipients. Different clinical manifestations have been described, including fever, skin rash, bone marrow suppression, and encephalitis.

Materials and Methods:

A retrospective review of a group of 26 adult recipients of allogeneic HSCTs was conducted. Serum samples taken before transplant were examined for the presence of specific anti-HHV-6 IgM and IgG antibodies. After transplantation, quantitative real-time PCR was used to determine viral load in plasma samples from days 0–80 post-transplant.

Results:

HHV-6 DNA was detected in plasma samples in 8 (30%) of the 26 recipients between days 18 and 40 after transplantation. All of them developed fever of unknown origin and over 50% had graft-versus-host disease features. Three individuals from this group died during detectable HHV-6 viremia. Another two recipients showed a single positive PCR result at a later time. Infection with HHV-6 was thus confirmed in 10 (38.5%) of the 26 graft recipients.

Conclusions:

There is a high frequency of detectable HHV-6 viral load in stem cell transplant recipients in Poland. Further investigation to monitor HHV-6 reactivation in graft recipients will be important to improve outcome for these patients.

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.

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.

[Real-time PCR as an efficient tool for investigating the presence of human herpesvirus 6 DNA]

Human herpesvirus 6 (HHV-6) is a beta-herpesvirus widely spread within a population and has been recognized as a potential significant pathogen in immunocompromised patients. Different clinical manifestations have been described including fever, skin rash, pneumonia, graft rejection and encephalitis. The goal of the study was development of real-time PCR assay for detection of human herpesvirus type 6 DNA in clinical samples, using primers targeting a conserved region of the viral DNA polymerase gene and a specific TaqMan hydrolyzing probe. The analytical sensitivity of assay was tested using serial dilutions of HHV-6 DNA in range between 10(0) and 10(-6). Thirty plasma samples taken from a group of adult recipients of allogeneic HSCT were tested for the presence of HHV-6 DNA in the LightCycler system. For comparison commercial quantitative MutaREAL HHV-6 kit (ALPCO) was used, according to the manufacturer's instructions. Both LightCycler assays, including in-house real-time PCR, detected HHV-6 DNA in 13 specimens. The conclusion is that developed TaqMan-based probes real-time PCR test is very reliable and valuable for detection of low-copy viremia in plasma samples. The high level of sensitivity and accuracy provided by the LightCycler instrument is favorable for the use of this method in the detection of HHV-6 DNA in clinical specimens.

Introgression mapping of genes for winter hardiness and frost tolerance transferred from Festuca arundinacea into Lolium multiflorum

Genes for winter hardiness and frost tolerance were introgressed from Festuca arundinacea into winter-sensitive Lolium multiflorum. Two partly fertile, pentaploid (2n = 5x = 35) F(1) hybrids F. arundinacea (2n = 6x = 42) x L. multiflorum (2n = 4x = 28) were generated and backcrossed twice onto L. multiflorum (2x). The backcross 1 (BC(1)) and backcross 2 (BC(2)) plants were preselected for high vigor and good fertility, and subsequently, a total of 83 BC(2) plants were selected for winter hardiness after 2 Polish winters and by simulated freezing tests. Genomic in situ hybridization (GISH) was performed on 6 winter-hardy plants selected after the first winter and shown to be significantly (P < 0.05) more frost tolerant than the L. multiflorum control. Among the analyzed BC(2) winter survivors, only diploid (2n = 2x = 14) plants were found. Five plants carried 13 intact L. multiflorum chromosomes and 1 L. multiflorum chromosome with a single introgressed F. arundinacea terminal chromosome segment. The sixth BC(2) winter survivor appeared to be Lolium without any Festuca introgression capable of detection by GISH. A combined GISH and fluorescence in situ hybridization analysis with rDNA probes of the most winter-hardy (after 2 winters) and frost-tolerant BC(2) plant revealed the location of an F. arundinacea introgression on the nonsatellite arm of L. multiflorum chromosome 2, the same chromosome location reported previously as a site for frost tolerance genes in the diploid and winter-hardy species Festuca pratensis.

Clostridium difficile and enterotoxigenic Bacteroides fragilis strains isolated from patients with antibiotic associated diarrhoea

From the fecal samples of 332 patients with a clinical diagnosis of antibiotic associated diarrhoea (AAD), 131 Clostridium difficile strains were isolated. For detection of toxin A in the isolated strains the enzymatic immunoassay was used. The cytopathic effect was determined on McCoy cell line. PCR was used for the detection of non-repeating and repeating sequences of toxin A gene and non-repeating sequences of toxin B gene. One hundred and six isolated C. difficile strains were TcdA(+)TcdB(+), 10 strains TcdA(-)TcB(+) and 15 were non-toxigenic TcdA(-)TcdB(-). Out of the same fecal samples 50 Bacteroides fragilis strains were isolated. All B. fragilis strains were tested in PCR reaction for fragilysine gene detection (bft). In 9 strains (18%) this gene was detected and the strains could be assumed as enterotoxigenic Bacteroides fragilis (ETBF). In 4 fecal samples toxigenic C. difficile (TcdA(+)TcdB(+)) was found simultaneously with ETBF. One sample contained C. difficile (TcdA(-)TcdB(+)) and ETBF. Out of 4 fecal samples only ETBF was isolated. The cytotoxicity of ETBF strains was tested on HT29/C1 human colon carcinoma cell line. The cytotoxicity titer in the range of 20 and 80 was observed.

Emergence and spread of carbapenem-resistant strains of Acinetobacter baumannii in a tertiary-care hospital in Poland

This study analysed the occurrence of carbapenem resistance among Acinetobacter baumannii isolates from a tertiary-care hospital in Poland, together with the molecular epidemiology of these isolates and the risk-factors for their acquisition and possible nosocomial spread. The medical charts of 21 patients with Acinetobacter infection or colonisation revealed that A. baumannii isolates were obtained most frequently from intensive care unit and surgical patients (particularly those receiving transplantation surgery). First isolation occurred, on average, on day 21 following admission (range 5-45 days). Infection with Acinetobacter contributed directly to the death of seven patients. Several patients were infected with more than one strain, and molecular typing revealed the co-circulation of three predominant clones, of which two belonged to the Acinetobacter lineages designated as European clones I and II. All three clones encoded an OXA-51-type carbapenemase, but were negative for carbapenemases belonging to the OXA-23, OXA-24 and OXA-58 families. The OXA-51 gene was found in both resistant and susceptible isolates, and was not associated directly with carbapenem resistance. Etests with imipenem and imipenem plus EDTA indicated production of a metallo-beta-lactamase (MBL) in carbapenem-resistant isolates. PCRs for IMP-type MBLs were negative, but PCR using consensus primers for VIM-type MBLs were positive for carbapenem-resistant isolates belonging to the European clone II lineage. The occurrence of a VIM-type MBL in association with one of the epidemic lineages of A. baumannii is a cause for concern. Further studies are needed to evaluate possible inter-hospital spread of resistant A. baumannii strains in Poland.

[Survey of susceptibility of clinical Clostridium diffiicile strains isolated from patients hospitalised in different departments of paediatric hospital to antimicrobial agents]

This study was performed to determine the susceptibility of 50 C. difficile strains isolated from faecal samples of children suspected to antibiotic associated diarrhea (AAD) to antimicrobial agents: metronidazole, vancomycin, erythromycin, clindamycin, ciprofloxacin, moxifloksacin, gatifloksacin and imipenem. The all C. difficile strains were sensitived to metronidazole and vancomycin. Twenty six per cent of strains were resistant to erythromycin and clindamycin (MLS(B) type resistance). Resitance to ciprofloxacin, moxifloxacin, gatifloxacin and imipenem was detected in 98%, 8%, 8% and 30% of C. difficile strains, respectively.

[Antibmicrobial susceptibility of Serratia marcescens isolated from hospitalized patients in 2003 - 2005]

500 strains of Serratia marcescens isolated in 2003-2005 were examined for drug susceptibility. By using several phenotypic methods it was shown that 67.6% of these strains produced ESBLs. Strains ESBL(-) and ESBL(+) were compared, paying special attention to their susceptibility to various antibiotics. It was revealed that strains ESBL(+) were much more resistant to majority of the investigated drugs. The biggest differences were in the case of amikacin and gentamicin, sensitive about 50% of ESBL(-) and 10% of ESBL(+), ciprofloxacin, sensitive 42% of ESBL(-) and 6.3% of ESBL(+) and trimethoprim/ sulphametoxazole, sensitive 45.8% of ESBL(-) and 9.4% of ESBL(+). Strains ESBL(-) retained a high susceptibility to ceftazidime (68.9%) and cefepime (71%). All strains ESBL(-) as well as ESBL(+) were susceptible to imipenem and meropenem. 78.9% of ESBL(-) and 67.3% of investigated ESBL(+) were susceptible to piperacillin/ tazobactam.

[Frequency of identification of cytomegalovirus DNA in patient of Public Independent Central Hospital in Warsaw in years 2002-2006]

OBJECTIVE

The present study shows frequency of presence of cytomegalovirus DNA in patients of Public Independent Central Clinical Hospital in Warsaw in years 2002-2006.

MATERIALS AND METHODS

2486 clinical samples taken from 604 patients in years 2002-2006 were tested for the presence of HHV-5 DNA using the qualitative in-house PCR method and quantitative real-time PCR assay.

RESULTS

Positive results were obtained in 5,3% of all examinations made during described period. All of positive samples came from Department of Hematology, Oncology and Internal Medicine patients--most of them was after stem cell transplantation.

CONCLUSIONS

These findings underline the value of PCR methods used in current diagnostics procedures. The high level of sensitivity and rapidity provided by this assays is favorable for the use in the detection fo HHV-5 DNA in clinical specimens.

[Estimation of activity of pharmakopeal disinfectants and antiseptics against Gram-negative and Gram-positive bacteria isolated from clinical specimens, drugs and environment]

The MIC of nine different disinfectants and antiseptics were determined for the Gram-negative and Gram-positive bacteria. Strains originated from clinical specimens, drugs and environment. A sensitivity was determined against chlorhexidinum digluconate (Gram-negative: 0,625-80 mg/L, Gram-positive: 0,3-10 mg/L), benzalconium chloride (Gram-negative: 2,5-1280 mg/L, Gram-positive: 1,25-20 mg/L), salicilic acid (Gram-negative and Gram-positive: 400-1600 mg/L), benzoic acid (Gram-negative: 800-1600 mg/L, Gram-positive: 400-1 600 mg/L), boric acid (Gram-negative: 800-12 800 mg/L, Gram-positive: 1 600-6400 mg/L), chloramine B (Gram-negative: 1600-6400 mg/L, Gram-positive:800- 6400 mg/L), jodine (Gram-negative: 200-1600 mg/L, Gram-positive: 200-1600 mg/L), etacridine lactate (Gram-negative: 40 do > 20480 mg/L, Gram-positive: 40-1280 mg/L) and resorcine (Gram-negative: 1600-6400 mg/L, Gram-positive: 800-6400 mg/L). Diversified values of MIC for different strains were obtained, especially in the case of benzalconium chloride, etacridine lactate, chlorhexidinum digluconate, boric acid and iodine. Strains isolated from environment were usually more susceptible to examined compounds than clinical strains. The biggest diversification of sensitivity was observed among strains originated from drugs where besides sensitive appeared strains characterizing by very high MIC values of some substances, eg. boric acid.

[The correlation between phenotypes and genotypes of macrolides, lincosamides and streptogramins B resistance in Staphylococcus aureus]

For 31 clinical strains of S. aureus the correlation between phenotype and genotype of resistance to macrolides, lincosamides and streptogramins B (MLSB) was established.. Phenotypes were determined on the basis of: susceptibility to erythromycin and clindamycin and the ability to an induction of the resistance (phenotypes S, susceptible; R , constitutive resistant, D, resistant after induction with erythromycin, D+, resistant after induction with erythromycin and with a presence of the small colonies inside inhibition zone between erythromycin and clindamycin discs), and on the basis of the resistance to spectinomycin (spR, resistant, spS, susceptible). Among examined S. aureus strains eight phenotypes of resistance to MLSB were recognized (the corresponding genotypes are given in brackets). Six phenotypes were typical: SspS (lack of MLS-B resistance genes), NEGspS (msrA/B, 1 strain), D+spS (ermCi, 4 strains),. DspR (ermAi, 11 strains and ermAi + msrA/B, 2 strains), RspR (ermAc, 4 strains and ermA + msrA/B,1 strain and ermA + ermC, 1 strain) and RspS (ermCc, 6 strains and ermB, 1 strain). Two rare phenotypes in two single strains were observed: SspR (ermAi, the strain with altered inducibility, inductor other than erythromycin) and DspS (ermAi, presumably mutation or lack of spc in Tn554).

Successful eradication of methicillin-resistant Staphylococcus aureus (MRSA) intestinal carrier status in a healthcare worker--case report

We describe bacteriophage therapy in the case of a healthcare worker whose gastrointestinal tract was colonized by methicillin-resistant Staphylococcus aureus (MRSA) with subsequent urinary tract infection caused by the same pathogen. Oral treatment with anti-MRSA phages resulted in eradication of the carrier status.

[Metallo-beta-lactamase-producing gram-negative rods isolated from inpatients and outpatients, detected using Etest MBL]

The aim of presented study was to detect MBL-positive strains in a group of clinical carbapenem-resistant strains isolated from inpatients and outpatients during last four years. From the beginning of November 2001 to the end of October 2005, one hundred and four strains resistant to carbapenem antibiotics--imipenem and meropenem were cultured from clinical samples obtained from patients of the Infant Jesus Clinical Hospital Centre for Trauma Treatment in Warsaw and from patients of outpatient clinics. Strains were identified and their susceptibility to antibacterial agents was determined in the automatic ATB Expression system (bioMérieux). Resistance to imipenem and meropenem was confirmed with a disc diffusion method. Production of metallo-beta-lactamases (MBL) was examined with the use of Etest MBL (AB Biodisk, Sweden), and extended-spectrum beta-lactamases (ESBL) by means of following procedures: DDST and / or DD (four variants) (Oxoid Ltd., England). MBL-positive strains (36) were cultured in cases of infections in adult patients (35 strains) and in a child (1 strain). Majority of strains belonged to the species P. aeruginosa (27), several strains - to the species P. putida (6) and remaining strains--to P. stutzeri, A. xylosoxidans, and E. cloacae (1 strain of each species). Four strains were producers of MBL-type and ESBL-type beta-lactamases. According to our knowledge and accessible literature described strains (except one paediatric strain) are the first MBL-positive strains isolated from adult hospitalized patients and adult ambulatory patients in Poland. Additionally, MBL-positive E. cloacae strain is probably the first MBL producer isolated in Poland, which belongs to the group of enteric rods. MBL-producing strains of Gram-negative rods, detected by phenotypic Etest MBL method, will be verified with genetic procedures.

[High effectiveness of the method with cefpirome in detection of extended-spectrum beta-lactamases in different species of gram-negative bacilli]

Gram-negative bacilli were examined for ESBL production by using four methods: double-disc synergy diffusion test (DDST), and three tests of combined discs with cefpodoxime, ceftazidime and cefotaxime alone and the same cephalosporins with clavulanic acid. Strains determined as ESBL-negative with all these tests were examined by using fifth method with cefpirome. 47,5% from 178 negative in other methods strains, appeared ESBL-positive in this test. The examined strains belonged to 16 different species. Most of them were Enterobacter cloaceae, Serratia marcescens, Pseudomonas aeruginosa and Acinetobacter baumanii. It seems that the combined discs method with cefpirome may be usefull for phenotypic detection of ESBL producing bacteria also in the case of strains where ESBL production is camouflaged with derepressed chromosomal AmpC beta-lactamases.

[The molecular characteristic of Staphylococcus aureus and Staphylococcus epidermidis strains isolated from clinical sources]

The aim of study was the molecular characteristic of S. aureus and S. epidermidis isolates obtained from skin surface, wounds, deep tissues of hospitalized patients and from skin surface of non-hospitalized patients. Genes encoding virulence factors were examined using PCR reaction and specific primers. Genes encoding adhesinsfnbA and cna and gene eta for epidermolytic toxin were mostly present in S. aureus isolates coming from wounds and deep tissues compared to these from skin surface. Gene atlE encoding autolysin of S. epidermidis was detected in all studied isolates, whereas gene icaAB was present in almost all isolates. Comparison of results obtained by PCR and conventional method of the resistance to methicillin estimation showed discrepances suggesting the need for using of both methods in some clinically difficult cases of S. aureus infection.

[The resistance to glycopeptide antibiotics among strains of Enterococcus sp. isolated in 1998-2005 from patients of one of the university hospitals in Warsaw]

Infections due to vancomycin resistant enterococci (VRE) constitute a serious therapeutic problem in some cases. Up to date there is only poor knowledge about the frequency of isolation of VRE inthe Polish hospitals. The aim of our investigations was to compare the number and the assortment of VRE isolated during eight years (1998-2005) in the one big clinical hospital in Warsaw. All resistant strains were checked for possessing the vanA or van B ligase genes in the PCR reaction. The identification of the strains was proven by PCR with using of the ddl primers. The significant increase in the number of VRE was observed in the 2005 compared with recent years. All strains isolated in recent years possessed vanA ligase genes. Although among all enterococci E. faecalis made majority (over 70%), among VRE predominated E. faecium.

[Influence of selected Lactobacillus sp. on Clostridium difficile strains with different toxigenicity profile]

This study was performed for determination of antagonistic activity of Lactobacillus spp. (L. plantarum 2017405, L. rhamnosus GG, L. acidophilus DSM 21007 and L. fernmentumn 353) on Clostridiunl difficile strains belonging to different toxigenicity profiles. Forty strains C. difficile isolated from patients suffering from antibiotic associated diarrhea (AAD) were used. Among C. difficile strains 13 produced toxin A and B (A+B+CDT-), 14 produced only toxin B (AB'CDT), 9 produced toxins A and B and possessing of binary toxin genes (A+B+CDT-) and 4 were non-toxigenic (A-B-CDT-). We did not observe relationship between degree of antagonistic activity Lactobacillus spp. and profile of toxigenicity of C. difficile strains.

Enzymatic Variability of Candida krusei Isolates in a Course of Fungal Infection in a Liver Transplant Recipient

Transplant recipients are at high risk of fungal infections. The main site of fungal infections in patients undergoing liver transplantation is the abdominal cavity. One factor determining the pathogenicity of fungi is their ability to secrete hydrolytic enzymes. The aim of this study was to assess the enzymatic activity of Candida krusei, which caused an infection in a liver transplant recipient. The clinical specimens included swabs of throat, nose, and two drains, as well as bile, stool, and abdominal cavity aspirate. The yeast-like fungi isolated were identified by an ID 32 C test (bioMérieux) and their enzymatic activity assayed with the use of an API-ZYM test. Two biotypes of C. krusei were identified, depending on the source of the clinical specimen. The C. krusei isolates cultured from a throat swab, a nasal swab, and one of the drains secreted esterase lipase C8 (enzyme IV) and valine arylamidase (enzyme VII), in contrast to those isolated from the bile, abdominal cavity fluid, another drain, and stool. Characterization of two biotypes of C. krusei isolates cultured from different clinical samples from several infection sites indicated an ability of C. krusei to adapt to variable environmental conditions.

[The frequency of the occurrence of genes ermA, ermB, ermC and msrA/B among methicillin-resistant Staphylococcus aureus strains resistant to erythromycin]

The group of 50 clinical MRSA strains resistant to MLS-B was examined for the presence of ermA, ermB, ermC, msrA/B genes by using PCR. Gene ermA was found in 43 strains (86%). 20 of ermA strains demonstrated inducible whereas 23 constitutive type of expression. The gene ermC was present in 15 of examined MRSA strains (30%). The expression of the gene was inducible in the case of 9 and constitutive in the case of 6 of the strains. The msrA/B gene was present in the case of 5 strains (10%). The ermB gene was not detected among the investigated strains.

[MIC and MBC of quinupristin/dalfopristin of erythromycin-resistant MRSA strains isolated from clinical specimens]

The MICs and MBCs of quinupristin/dalfopristin were determined for 22 clinical strains MRSA with inducible type of resistance to MLS-B and for 15 of their derivatives with constitutive resistance to MLS-B. For MRSA strains with inducible resistance to MLS-B the obtained results for quinupristin/ dalfopristin were: MIC50 = 0.25, MIC90 = 0.5, MBC50 = 1.0 and MBC90 = 1.0. Mutants of the same strains characterized with the following values for quinopristin/dalfopristin: MIC50 = 0.5, MIC90 = 1.5, MBC50 = 4.0 and MTC90 = 8.0.

[Sensitivity of Staphylococcus aureus strains isolated from the patients of the SP ZOZ Hospital in Nidzica to bacteriocidal agents]

The aim of this study was to evaluate a frequency of isolation and antimicrobial susceptibility testing of Staphylococcus aureus strains isolated from clinical specimens obtained from patients hospitalized in different hospital wards (SP ZOZ) in Nidzica from 01. 09. 2000 to 31. 12. 2003. During over three years 716 Staphylococcus aureus strains were cultured out of 15517 clinical specimens supplied to the Bacteriological Laboratory of SP ZOZ in Nidzica. S. aureus strains were isolated from 4.6% of examined samples. Samples were collected from patients hospitalized in all wards (five wards). Analysis of susceptibility to antimicrobial agents of identified S. aureus strains was performed. Seventy strains (9.8%) were metihicillin-resistant (MRSA). One hundred twenty four strains (17.3%) revealed inducible resistance to macrolides, linkosamides and streptogramins B (MLS, mechanism). The greatest activity in vitro against clinical S. aureus strains showed glycopeptide antibiotic--vancomycin (100% of susceptible strains). Clinical S. aureus strains isolated from patients of hospital in Nidzica are in the majority susceptible to antibiotics/chemotherapeutics, except of penicillin. Percentage of methicillin-resistant strains (MRSA) is not high (<10). Nevertheless, constant monitoring of a drug susceptibility of nosocomial S. aureus strains is important, considering the necessity of control of current epidemiological and therapeutic situation.

Cytotoxic, antiviral (in-vitro and in-vivo), immunomodulatory activity and influence on mitotic divisions of three taxol derivatives: 10-deacetyl-baccatin III, methyl (N-benzoyl-(2'R,3'S)-3'-phenylisoserinate) and N-benzoyl-(2'R,3'S)-3'-phenylisoserine

The aim of this study was to evaluate cytotoxic, antiviral (in-vitro and in-vivo) and immunomodulatory activity, as well as the influence on mitotic division, of three taxol derivatives representing modified parts of its molecule: 10-deacetyl-baccatin III, methyl (N-benzoyl-(2'R,3'S)-3'-phenylisoserinate) and N-benzoyl(2'R,3'S)-3'-phenylisoserine. The cytotoxicity of the compounds, assessed by the formazane method, was relatively low, with a 50% cytotoxic concentration (CC50)>500 microg mL-1. Moreover, all tested compounds inhibited Herpes simplex type 1 virus (HSV-1) replication in non-cytotoxic concentrations in-vitro. Selectivity indices were in the range 9.5-46.7. Anti-HSV-1 activity of the compounds may be associated with their influence on mitotic division. All of the compounds decreased the number of cell divisions. Mitotic indices ranged from 40/1000 (4.0%) to 62/1000 (6.2%). One compound, 10-deacetyl-baccatin III, influenced the growth of tumours induced in mice by infection with Moloney murine sarcoma virus. The effect of the tested compounds on T lymphocyte proliferation was evaluated by measurement of the activity of tritiated thymidine incorporated into DNA of dividing cells. One compound, methyl (N-benzoyl-(2'R,3'S)-3'-phenylisoserinate), inhibited T lymphocyte proliferation. This paper demonstrates that modified parts of the taxol molecule possess various types of biological activity in-vitro and in-vivo. Further experiments, focused on revealing their mechanisms of action, are necessary.

Immunomodulatory activity and influence on mitotic divisions of N-benzoylphenylisoserinates of Lactarius sesquiterpenoid alcohols in vitro

Six N-benzoylphenylisoserinates of Lactarius sesquiterpenoid alcohols, which previously showed antiviral activities, were tested for their biological properties. Their influence on the mitotic division of the cells and on selected immunological parameters, e. g., T and B lymphocyte proliferation and synthesis of the cytokines: interleukin 2 (IL-2), tumour necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) was assessed in vitro. All of the tested compounds significantly decreased the number of cell divisions. It appears that their influence on cellular divisions may be associated with anti-HSV activity. Moreover, one compound - isolactarorufin 8-epi-[N-benzoyl-(2' R,3' S)-3'-phenylisoserinate] significantly inhibited T lymphocyte proliferation and the synthesis of all tested cytokines.

Infection by a Dimorphic Fungus Sporothrix schenckii in an Immunocompromised Patient

Infections caused by dimorphic fungi, rarely observed in a temperate climate, may cause chronic infections in immunocompromised patients. We describe a case of sporotrichosis in a 50-year-old woman, who underwent mastectomy due to breast carcinoma, followed by radiation and chemotherapy. She developed skin lesions, localized along the lymphatics. Discharge samples repeatedly yielded a characteristic growth of the dimorphic fungus Sporothrix schenckii. The isolate was resistant to all commonly used antifungal agents, except for itraconazole. Therapy with this antifungal agent resulted in disappearance of the clinical symptoms.

[The combined effect of methicillin and teicoplanin against Staphylococcus aureus strains investigated in vitro]

The synergy or antagonism between teicoplanin and methicillin against the methicillin-resistant strains of Staphylococcus aureus with decreased susceptibility to vancomycin was studied using agar dilution and E-tests. The investigated strains were GISA and h-GISA isolated in our laboratory as well as standard. In the used range of concentrations, a synergy was shown in the case of two strains and an antagonism was shown in the case of other two strains. For the most strains the tested combination of antibiotics showed indifference. The antagonistic effect was observed in the case of the standard strain Mu3 and the one from eight strains h-GISA isolated in our laboratory.

[Antiviral and cytotoxic activities of new derivatives of natural sesquiterpenes and taxol]

Common occurrences of serious viral infections and a small number of available antiviral chemotherapeutics necessitate research for new, biologically active substances, which might be of use as antiviral drugs. Natural compounds, e.g., derived from plants and fungi, which show significant and various biological activities, may be a source of potential drugs. Sesquiterpenes, as well as taxol, and their derivatives, may serve as an example. The aim of the present study was to investigate the antiviral, antibacterial and cytotoxic properties of 7 new compounds: derivatives of sesquiterpenes of Lactarius mushroom origin and taxol--N-benzoylphenylisoserinates of sesquiterpenoid alcohols. The cytotoxicity of the tested compounds against Vero, RD, LLC-MK2 and A549 cell lines were assessed using the formazan method. All compounds showed a lower cytotoxicity than taxol. Their antiviral activity in vitro was evaluated by assessing the reduction of virus titre in cells subjected to the compounds in comparison to the cells, which were not subjected to them. It was found that out of 7 investigated compounds 3 exhibited antiviral activity. These compounds inhibited replication of HSV-1 virus in Vero cells. It appears therefore that further investigation of these groups of compounds and their derivatives is justified because they may constitute a potential source of chemotherapeutics.

[Role of obligate anaerobes in infections in hospitalized patients and therapeutic options]

Monitoring of prevalence and antibiotic susceptibility of strictly anaerobic bacteria, causing infections in hospitalized patients, constitutes a part of a program for prudent use of antibiotics. The aim of the study was to assess prevalence of strictly anaerobic bacteria in patients hospitalized in a tertiary care hospital in 2001-2002 with reference to empiric antibiotic therapy. The most common gram-positive bacteria were Clostridium difficile--27.7%, Peptostreptococcus spp. and Peptoniphilus asaccharolyticus--21.9% and Actinomyces spp.--11.1%. There was an increase in the number of stool samples positive for C. difficile toxins A and B from 39.4% in 2001 to 59.0% in 2002. The results of susceptibility testing of gram-positive isolates showed the highest percentages of strains susceptible to piperacilin/tazobactam--99.6%, ticarcillin/clavulanate--98.5%, imipenem--98.5%, amoxicillin/clavulanate--97.4% and piperacillin--97.4%. The most prevalent gram-negative anaerobes were strains of Bacteroides spp.--43.1%, Prevotella spp.--35.8% and Fusobacterium spp.--11.0%. All tested strains of gram-negative bacteria were susceptible to metronidazole, piperacilin/tazobactam, ticarcillin/clavulanate and imipenem. In the analyzed population beta-lactam antibiotics with beta-lactamase inhibitors, carbapenems and metronidazole may be used in empiric therapy of infections caused by strictly anaerobic bacteria.

Bacteriological urinalysis in patients after renal transplantation

The study consisted of microbiological urinalysis performed in 269 patients after renal transplantation who remained under medical care at the Outpatient Service of the Transplantation Institute in Warsaw. The patients enrolled into the study had undergone renal transplantation 6 to 72 months before urine samples were collected. 304 urinalysis were performed. In the group of 269 patients, 42 individuals had bacteria in their urine what was confirmed in 47 urine cultures. Cases of bacteriuria were divided into 5 groups: 5 cases of symptomatic urinary tract infection (5 individuals--2% of all studied patients), 27 cases of asymptomatic bacteriuria in 22 individuals (8% of all studied patients), 5 cases of insignificant bacteriuria in 5 patients (2%), 10 cases of involuntary urine contamination in 10 cases (4%). Eventually, urinary tract infection (UTI) was established in 27 patients (5 cases of symptomatic UTI and 22 cases of asymptomatic UTI) what makes out for 10% of all studied patients. In cases where urinalysis showed significant bacteriuria, following pathogens were detected in urine cultures: Escherichia coli: 22 strains, Enterococcus faecalis--4 strains, Enterobacter cloacae--2 strains and 1 strains of Ralstonia picketii, Streptococcus uberis, Pseudomonas aeruginosa and Proteus mirabilis. Over 90% of Gram-negative bacteria were susceptible to ceftriaxone and ceftazidime, as well as to amikacin and aztreonam which are the drugs usually administered intravenously in hospitalized patients. The only drug of similar efficacy, which could be administered orally in outpatients was fosfomycin.

[Application of four variants of the diagnostic disc test (CD01, CD02, CD03, CD04) for detection of ESBL-positive strains of gram-negative rods]

The aim of this study was to evaluate the usefulness of four variants of the diagnostic disc test (DD) to detect extended-spectrum beta-lactamases (ESBLs) in nosocomial strains of gram-negative rods. Also, the diagnostic disc test (DD) was compared with the double-disc synergy test (DDST) for the effectivity of ESBLs identification. A total number of 111 ESBL-positive (DDST-positive) strains of gram-negative rods isolated from hospitalized patients in 2004 was examined. Ninety nine strains belonged to enteric rods (89.2%) and twelve strains--to nonfermentative rods (10.8%). Two reference strains: E. coli ATCC 25922 (ESBL-negative one) and K. pneumoniae ATCC 700603 (ESBL-positive one) were included in the study. Four variants of the diagnostic disc test (DD, Oxoid Ltd, UK) were applied for ESBLs detection: CPD/CD01, CAZ/CD02, CTX/CD03 and CPO/CD04. All examined strains (111) were DDST-positive. Positive results in the DD test (Oxoid Ltd) were as follows: CPD/CD01--59 strains (53.2%), CAZ/CD02--80 strains (72.1%), CTX/CD03--92 strains (82.9%) and CPO/CD04--110 strains (99.1%). Discs containing cefpirome (CPO) and cefpirome with clavulanic acid (CD04) were the best set for detection of ESBLs in our collection of clinical gram-negative rods. Results of this variant of the DD test were the most consistent with the results of the DDST. Application of several disc diffusion methods to detect ESBL producers increases the probability of proper identification of these strains.

[Comparison of frequency and susceptibility to antimicrobials of bacterial strains of the family Enterobacteriaceae isolated from patients hospitalised in intensive care units]

The aim of the study was estimation of frequency and susceptibility to antimicrobial agents of gram-negative rods isolated from clinical specimens obtained from patients requiring intensive care, with emphasis on profile of the unit. The analysis comprised strains of gram-negative rods isolated from patients of two intensive care units (ICUs) of a tertiary care hospital (1200 beds). Identification of cultured isolates was done using automated VITEK and API systems (bioMerieux, France). Susceptibility to antimicrobial agents was tested by a disk-diffusion method according to the NCCLS recommendations. In total the analysis comprised 722 strains of gram-negative rods. In blood cultures predominated strains of Enterobacter spp. (42.5%) and Klebsiella pneumoniae (37.5%). In cultures of clinical specimens other than blood 41.6% comprised strains of Klebsiella pneumoniae, 14.8% Escherichia coli and 14.4% Proteus mirabilis. Frequency of multi-drug resistant strains of bacteria of the family Enterobacteriaceae was much higher among blood isolates in comparison to strains cultured from other clinical specimens. There was a relatively high percentage of strains of Enterobacteriaceae susceptible to piperacillin and tazobactam (69.0%) and ceftazidime (54.6%).

CONCLUSIONS

1. All strains were susceptible to carbapenems. 2. There was a relatively high percentage of strains of gram-negative rods susceptible to piperacillin/tazobactam and ceftazidime. 3. Bacteria isolated from blood cultures were characterised by a much higher percentage of resistant strains in comparison to other specimens. 4. Longer stay in ICU promoted selection of strains resistant to antimicrobials.

[Contribution of Pseudomonas Aeruginosa strains to infections in patients of specialistic outpatients clinics of the SP ZOZ in Nidzica]

The aim of this study was to examine a frequency of isolation and analysis of drug susceptibility o P. aeruginosa strains cultured from clinical specimens obtained from patients treated in specialistic outpatient clinics of the Samodzielny Publiczny Zespół Opieki Zdrowotnej (SP ZOZ) in Nidzica durin 40 months (01. 09. 2000 - 31. 12. 2003). Ninety six P. aeruginosa strains were cultured out of 829 clinical samples collected from ambulatory patients and processed in the Bacteriological Laboratory of SP ZOZ in Nidzica during over three years. P. aeruginosa strains were isolated from 11.6% of examined specimens. The greatest number of strains (49.0%) were cultured from urine samples obtained from children. Identification of strains was performed using biochemical tests (Becton Dickinson, Emapol, bio-Merieux). Susceptibility of strains to antimicrobial agents was determined with disc diffusion method according to NCCLS recommendations. Special tests were applied to detect extended-spectrum beta-lactamases (ESBL). The most active in vitro against isolated P. aeruginosa strains was a carbapenem - imipenem. All strains were susceptible to this antibiotic. Ciprofloxacin (94.8% of susceptible strains), ceftazidime (89.6%), gentamicin (86.5%), piperacillin (84.4%) and aztreonam (76.0%) were active against the majority of P. aeruginosa strains isolated from ambulatory patients. Six strains (6.25% of all strains) producing extended--spectrum beta--lactamases (ESBL) were detected. It is alarming, that the majority of P. aeruginosa strains from outpatients were cultured out of pediatric samples (61.5%). Because of an increase in resistance and appearance of new mechanisms of resistance to antibiotics/chemotherapeutics in P. aeruginosa strains, it is necessary to monitor a drug susceptibility of these strains causing infections in ambulatory patients.

[Profile of toxigenicity of Clostridium difficile strains isolated from paediatric patients with clinical diagnosis of antibiotic associated diarrhea (AAD)]

This study was performed to determine profile of toxigenicity of 18 Clostridium difficile strains isolated from paeditric patients suffering from antibiotic associated diarrhea (AAD). Toxigenicity of C. difficile strains was tested for detection toxin A and toxin B by phenotypic methods and for detection of the tcdA and tcdB genes using of PCR. Changes in the repeating regions of the tcdA genes were detected with the NK9/NKV011 primer pairs. For detection of binary toxin (CDT) cdtA and cdtB genes, cdtApos/cdtArev i cdtBpos/cdtBrev two pair primers in PCR was used. Among C. difficile strains was detected three profiles of toxigenicity: C. difficile strains possesing of tcdA and tcdB genes but not possesing cdtA and cdtB genes of binary toxin (A+B+CDT-), strains possesing tcdA and tcdB and cdtA and cdtB genes (A+B+CDT+), strains with deletion of toxin A gene (A-B+CDT-). This is the first report on the occurence of binary positive C. difficile strains isolated from paediatric patients.

[Strains of genus Salmonella isolated from extraintestinal infections]

Every year in Poland from tens to more than hundred bacteriologically verified extraintestinal infections caused by Salmonella species have been registered. These unusually located infections have substantially heavy course and in many cases hospitalisation and antibiotic therapy have to be involved. Cases of extraintestinal infections with these Gram-negative rods, which were described in the literature, concerned: pneumonias, lung abscesses and thoracic empyemas, and infections of: blood, bones and joints, wounds, fistulas and urinary tract. The aim of this study was to set extraintestinal Salmonella infections and to analyze a susceptibility of isolated strains to antimicrobial agents. Between 01.07.2002 and 31.12.2004 (30 months) 13 strains of Salmonella genus have been isolated, including 11 S. enteritidis and 2 S. Hadar. In general, with one exception, isolated strains were susceptible to tested antibiotics/chemotherapeutics. ESBL - positive strains were not detected. The tendency of Salmonella strains to cause extraintestinal infections has been noticed. The problem is still escalating, especially in group of patients chronically treated, with immunodeficiency and immunosuppression, after complicated medical procedures, also in the group of small children and aged persons. Therefore, it is necessary to evaluate a susceptibility to antibiotics/chemotherapeutics of every strain from confirmed case of Salmonella extraintestinal infection and it is important to apply a guided therapy.

Detection of Clostridium difficile and its toxin A (TcdA) in stool specimens from hospitalised patients

The study has been carried out to determine the frequency of C. difficile recovery in stool cultures and the rate of C. difficile toxin A detection in faecal specimens of patients with nosocomial diarrhoea. Clinical specimens comprised 4414 stool samples collected from 1998 to 2002 from adult patients hospitalised in different wards of a university-affiliated hospital (1200 beds) and suspected of C. difficile-associated disease (CDAD). There have been 1308 (29.6%) specimens positive for C. difficile culture (15.1% in 1998, 29.5% in 1999, 33.8% in 2000, 31.2% in 2001 and 32.0% in 2002). The highest number of C. difficile strains was cultured from stool samples of patients hospitalised in the haematology/oncology ward (51.1% of all isolates), neurology (8.3%), nephrology (8.0%), gastrointestinal surgery (7.0%) and neurosurgery (6.2%) wards. The testing for C. difficile toxin A yielded 847 (19.2%) positive samples and 3567 (80.8%) toxin A-negative results. The percentage of C. difficile toxin A-positive samples was 29.4% in 1998, 17.5% in 1999, 23.2% in 2000, 17.1% in 2001 and 15.0% in 2002. In the analysed period we observed an increase in the number of stool specimens tested for C. difficile and an increase in the number of C. difficile culture-positive samples. A decrease in the number of C. difficile toxin A-positive samples was noted in the last 2 years of the study. This phenomenon may be due to an improved antibiotic policy of the hospital.