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W Hryniewicz

Publications and source records attributed to W Hryniewicz.

At least 55 records · Page 3Linked to original sources
PubMed1998

Susceptibility patterns of Enterococcus spp. isolated in Poland during 1996.

Susceptibility of Enterococcus spp. isolated from various clinical specimens to different antimicrobial agents was evaluated. Of the 346 enterococcal isolates obtained from four regional Polish hospitals during 6 months of 1996, 261 (75.4%) were identified as Enterococcus faecalis, 75 (21.7%) as Enterococcus faecium and ten (2.9%) as other enterococcal species. High-level resistance to gentamicin was expressed by 33.4% of E. faecalis and 86.5% of E. faecium strains and corresponding streptomycin resistance by 43.9 and 82.4%, respectively. Over 80% of E. faecium isolates were resistant to ampicillin. None of the isolates was resistant to teicoplanin, however 7.9% of E. fecalis and 1.4% of E. faecium strains were moderately susceptible to vancomycin.

Anti-Bacterial Agents↗
PubMed1998

Comparison of genetic characteristics of MRSA strains present in a Warsaw hospital in 1992 and 1996.

Nine isolates of methicillin-resistant Staphylococcus aureus (MRSA) collected in a Warsaw hospital in 1996 were typed by phenotypic (resistograms) and genotypic (PFGE and plasmid restriction analysis-REAP) methods. Twenty-four (MRSA) strains collected in this hospital during a period of the same duration in 1992 and typed earlier using resistograms and PFGE were also typed by REAP. Comparison of typing results obtained for isolates from 1992 and 1996 showed that strains characterised by PFGE patterns of two distinct types described as specific of the two clonally related groups of Polish MRSA in a multicentre study in 1992 are continuously present in the hospital. However, MRSA strains representing PFGE patterns not observed before were also found within the collection from 1996. REAP typing has proved to have a discriminatory power similar to that of PFGE analysis. Nevertheless, due to the lack of plasmids or difficulties in plasmid DNA isolation in 3 out of 33 studied strains, the typability of REAP turned out to be lower than that of PFGE.

Anti-Bacterial Agents↗
PubMed1998

Recombinational exchanges at the capsular polysaccharide biosynthetic locus lead to frequent serotype changes among natural isolates of Streptococcus pneumoniae.

Serotype 19F variants of the major Spanish multiresistant serotype 23F clone of Streptococcus pneumoniae have been proposed to have arisen by recombinational exchanges at the capsular biosynthetic locus. Members of the Spanish multiresistant serotype 23F clone and the serotype 19F variants were confirmed to be essentially identical in overall genotype, as they were indistinguishable by REP-PCR, and had identical sequences at three polymorphic housekeeping genes. Eight serotype 19F variants were studied and all had large recombinational replacements at the capsular biosynthetic locus. In all cases, one of the recombinational cross-over points appeared to be upstream of dexB, which flanks one end of the capsular locus, and in six of the variants the other cross-over point was downstream of aliA, which flanks the other end of the locus. In two strains a recombinational cross-over point between the introduced serotype 19F capsular region and that of the Spanish serotype 23F clone could be clearly identified, within cpsN in one strain and within cpsM in the other. The differences in the recombinational junctions and sequence polymorphisms within the introduced capsular genes, suggested that the eight serotype 19F variants emerged on at least four separate occasions. Changes in capsular type by recombination may therefore be relatively frequent in pneumococci and this has implications for the long-term efficacy of conjugate pneumococcal vaccines that will protect against only a limited number of serotypes.

Base Sequence↗
PubMed1998

Susceptibility testing of Klebsiella spp.--an international collaborative study in quality assessment.

In order to compare the prevalence of antibiotic resistance in different geographical areas, it is necessary to ensure agreement between laboratories on the assignment of strains to 'susceptible' and 'resistant' categories. An international quality assessment was performed to investigate the performance of susceptibility testing of Klebsiella spp. Ninety-five strains of klebsiellae were selected from clinical isolates at the London Hospital Medical College (LHMC). These included strains with a diversity of susceptibility profiles to amoxycillin/clavulanate, piperacillin, ceftazidime, cefuroxime, ciprofloxacin, gentamicin and trimethoprim. The strains were sent to 13 participating laboratories in Europe and the USA and laboratories were asked to test the susceptibility of these strains to these antibiotics by their usual methods. They were also asked to provide details of the method used to test susceptibility. Several different standard recommended testing methods were used. Reporting of susceptibilities was generally accurate, but a number of anomalies were noted. Discrepancies of reporting between the LHMC and the participating laboratories was more marked for resistant strains, particularly in the detection of resistance to cefuroxime and ciprofloxacin, as well as the assignment of susceptibility and resistance to piperacillin and amoxycillin/clavulanate. Some discrepancies could be attributed to the use of different breakpoints, leading to differing assignment of susceptibility. Methodological variations including disc content, inoculum and failure to measure and interpret zone sizes consistently also led to anomalies. This quality assessment programme has helped to identify problems in susceptibility testing which should be investigated further.

Anti-Bacterial Agents↗
PubMed1998

Outbreak of ceftazidime-resistant Klebsiella pneumoniae in a pediatric hospital in Warsaw, Poland: clonal spread of the TEM-47 extended-spectrum beta-lactamase (ESBL)-producing strain and transfer of a plasmid carrying the SHV-5-like ESBL-encoding gene.

In 1996 a large, 300-bed pediatric hospital in Warsaw, Poland, started a program of monitoring infections caused by extended-spectrum beta-lactamase (ESBL)-producing microorganisms. Over the first 3-month period eight Klebsiella pneumoniae isolates were identified as being resistant to ceftazidime. Six of these were found to produce the TEM-47 ESBL, which we first described in a K. pneumoniae strain recovered a year before in a pediatric hospital in Lódź, Poland, which is 140 km from Warsaw. Typing results revealed a very close relatedness among all these isolates, which suggested that the clonal outbreak in Warsaw was caused by a strain possibly imported from Lódź. The remaining two isolates expressed the SHV-5-like ESBL, which resulted from the horizontal transfer of a plasmid carrying the blaSHV gene between nonrelated strains. The data presented here exemplify the complexity of the epidemiological situation concerning ESBL producers typical for large Polish hospitals, in which no ESBL-monitoring programs were in place prior to 1995.

Ceftazidime↗
PubMed1998

Ceftazidime-resistant Enterobacteriaceae isolates from three Polish hospitals: identification of three novel TEM- and SHV-5-type extended-spectrum beta-lactamases.

Twelve ceftazidime-resistant isolates of the family Enterobacteriaceae (11 Klebsiella pneumoniae isolates and 1 Escherichia coli isolate) were collected in 1995 from three Polish hospitals located in different cities. All were identified as producers of extended-spectrum beta-lactamases (ESBLs). Detailed analysis of their beta-lactamase contents revealed that six of them expressed SHV-5-like ESBLs. The remaining six were found to produce three different TEM enzymes, each characterized by a pI value of 6.0 and specified by new combinations of amino acid substitutions. The amino acid substitutions compared to the TEM-1 beta-lactamase sequence were Gly238Ser, Glu240Lys, and Thr265Met for TEM-47; Leu21Phe, Gly238Ser, Glu240Lys, and Thr265Met for TEM-48; and Leu21Phe, Gly238Ser, Glu240Lys, Thr265Met, and Ser268Gly for TEM-49. The new TEM beta-lactamases, TEM-47, TEM-48, and TEM-49, belong to a subfamily of TEM-2-related enzymes. Genes coding for TEM-47 and TEM-49 could have originated from the TEM-48-encoding sequence by various single genetic events. The new TEM derivatives probably document the already advanced microevolution of ESBLs ongoing in Polish hospitals, in a majority of which no monitoring of ESBL producers was performed before 1996.

Bacterial Proteins↗
PubMed1998

Clonal distribution of methicillin-resistant Staphylococcus aureus in Poland.

We report on a study of 158 methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates obtained from 1990 to 1996 in 18 different hospitals in Poland. All isolates were recovered from infection and carriage sites of patients, carriage sites of health care personnel, and hospital environment samples. Fifty-seven MRSA strains described here were studied previously and these were divided into two different clusters according to the degree of heterogeneity of methicillin resistance expression. The aim of this study was to extend the correlation between the two clusters and identify the clonal identities among all isolates by a combination of different methodologies: (i) analysis of mecA polymorphs and Tn554 insertion patterns and (ii) determination of pulsed-field gel electrophoresis patterns of chromosomal SmaI digests. Ninety-seven of 158 strains showed a heterogeneous expression of resistance to methicillin. Among these, 75 (77.3%) were ClaI-mecA type I, ClaI-Tn554 type NH (NH, no homology with transposon Tn554), and pulsed-field gel electrophoresis (PFGE) pattern A (I::NH::A); 10 isolates were III::B::M (10.3%); and the remaining clones included a few or single isolates. The isolates with homogeneous expression of resistance to methicillin (n = 61) were predominantly ClaI-mecA type III (49 of 61 [80.3%]) but had great variability in their ClaI-Tn554 and PFGE patterns. This study confirmed the existence of two main clusters of MRSA in Poland.

Bacterial Typing Techniques↗
PubMed1998

[Susceptibility of Pseudomonas aeruginosa isolated from hospital infections to antibiotics].

A total of 674 clinical isolates of Pseudomonas aeruginosa were collected from 30 different hospitals located in 26 cities of Poland. These were 12 big regional hospitals, 7 large teaching hospitals, 4 specialised hospitals curing patients from the whole country, 6 small local hospitals and one regional paediatric hospital. The majority of strains were collected from patients hospitalised at ICUs (25.7%), surgical (21.7%), and internal medicine wards (9.9%). The isolates were recovered from different types of infections, mostly from respiratory tract infections (33.7%), wound infections (22.3%), and urinary tract infections (22.0%). All the isolates were subjected to antimicrobial susceptibility testing by MIC values evaluation. MICs of 13 different antibiotics (beta-lactams, aminoglycosides, chinolones) were determined by the agar dilution method. The general level of resistance of P.aeruginosa observed in the study was high, especially when compared to results of surveys obtained in other countries. Out of the antimicrobials used the highest activity in vitro was observed with meropenem, imipenem, piperacillin--tazobactam and ceftazidime. The high in vitro activity of ceftazidime was striking considering the long time of the use of this antibiotic in Polish hospitals. The highest levels of resistance were observed to some of the aminoglycosides. Populations of strains isolated in different wards or hospitals of different size were characterised by different susceptibility patterns.

Anti-Bacterial Agents↗
PubMed1998

[The use of molecular biology in the modeling of Pseudomonas aeruginosa strains recovered from nosocomial infections].

Different methods of molecular typing (ribotyping, genomic DNA RFLP and RAPD) were tested on Pseudomonas aeruginosa strains isolated in Polish hospitals in order to elaborate a reliable typing scheme for epidemiological investigations. The combined RAPD analysis with the use of two different primers, RAPD-4 and RAPD-7, was found to have the highest discriminatory power which considering also the easiness and low time-consumption has suggested its high usefulness in studies of outbreaks caused by P. aeruginosa. Ribotyping was shown to be the least discriminatory, however, especially with the use of the PvuII restriction enzyme, this method can be very useful in revealing the genetic structure of P. aeruginosa populations persisting in hospital environments over longer periods. Clonal relations within populations of strains isolated in four different hospitals were revealed. In two of the hospitals P. aeruginosa populations demonstrated a very high diversity which suggested that infections had been caused by strains of different origins, probably introduced from other environments. P. aeruginosa strains from two remaining hospitals were found to form some clonally related clusters what revealed that in these hospitals epidemic strains of this microorganism have been circulating for prolonged periods and infecting predisposed patients.

Bacterial Typing Techniques↗
PubMed1997

Binding of extracellular matrix proteins by enterococci.

Forty-four enterococcal strains isolated from human clinical specimens were investigated for binding of 125I-labeled fibronectin, vitronectin, thrombospondin, lactoferrin, and collagen type I and IV, and for cell surface hydrophobicity. Most strains expressed low binding of iodine-labeled human fibronectin, collagen I and IV, and higher binding of human vitronectin, human lactoferrin, and human thrombospondin. Bacteria grown in Todd-Hewitt broth exhibited increased binding to vitronectin and thrombospondin. In particle agglutination assays (PAA), Enterococcus faecalis strains reacted strongly with coated latex beads in contrast to E. faecium strains, which generally did not react. The ability of enterococci to bind ECM proteins was affected by heating and proteolytic digestion, suggesting that some protein-binding components become surface exposed after treatment with proteases. The binding of 125I-labeled proteins to E. faecalis strain E70 was inhibited when cells were preincubated with unlabeled proteins. Preincubating cells with sulfated polymers such as dextran sulfate (Mr 5000 and 8000), pentosan sulfate and heparin decreased binding of vitronectin, lactoferrin, and thrombospondin. The binding of lactoferrin and thrombospondin was also decreased when bacteria were preincubated with galactose, fucose, and mannosamine, but not with mannose. All of 30 E. faecalis strains expressed pronounced surface hydrophobicity, but 10 of 14 E. faecium strains showed hydrophilic cell surface.

Ammonium Sulfate↗
PubMed1997

Simultaneous persistence of methicillin-resistant and methicillin-susceptible clones of Staphylococcus aureus in a neonatal ward of a Warsaw hospital.

Fifty-seven methicillin-resistant Staphylococcus aureus (MRSA) isolates from babies (N = 31), carriers amongst health care workers (N = 16; 10% of all staff members) and the environment (N = 10); 39 MSSA isolates, from babies (N = 18), health care workers (N = 5) and environment (N = 16) were analysed. The strains were from the neonatal ward of a teaching hospital in Warsaw and were collected over a period of 16 months (1993/1994). The isolates were characterized by phage-typing, arbitrary-primed polymerase chain reaction (AP PCR), DNA repeat polymorphism within the protein A gene and the resistance pattern to antimicrobial agents. The presence of the mecA gene was determined by PCR. MRSA were classified as heterogeneously resistant to methicillin, susceptible to other antimicrobial agents and, except for three isolates, appeared to be genotypically almost identical. The first example of mupirocin resistant MRSA in Poland was documented. Amongst MSSA isolates, increased variability was seen, however, the persistence of one predominate clone of MSSA was shown. In this particular hospital environment, several different strains of both MRSA and MSSA were capable of maintaining persistent colonization.

Bacteriophage Typing↗
PubMed1996

Carriage of antibiotic-resistant Streptococcus pneumoniae by children in eastern and central Europe--a multicenter study with use of standardized methods.

With use of standardized techniques, a study of nasopharyngeal pneumococcal carriage in children in six Central and Eastern European cities was undertaken during the winter of 1993-1994. Nasopharyngeal swab specimens were collected from 954 children (predominantly under the age of 5 years) who were hospitalized or attending outpatient clinics or day-care centers. Susceptibility of isolates was determined by disk diffusion (on Mueller-Hinton agar with 5% sheep blood). Disks containing 1 micrograms of oxacillin were used to screen for susceptibility to penicillin G. Pneumococci were recovered from 258 (27.0%) of the 954 children. A variety of strains were recovered, and most penicillin-resistant strains were ŕesistant to multiple agents. Minimum inhibitory concentrations of penicillin for selected resistant strains were 0.125-8 micrograms/mL. Resistance to penicillin was common in strains from Bulgaria, Romania, and Slovakia. Resistance to erythromycin and chloramphenicol occurred in Bulgarian and Romanian strains. Strains from Poland were all susceptible to penicillin, but many were resistant to tetracycline. Resistance to trimethoprim-sulfamethoxazole was common in Bulgarian, Romanian, and Slovak strains. Czech and Russian strains were predominantly susceptible to antibiotics. Most resistant strains were of serotypes 6, 14, 19, and 23.

Carrier State↗
PubMed1996

Susceptibility testing of Haemophilus influenzae--an international collaborative study in quality assessment.

In order to compare the prevalence of antibiotic resistance in different geographical areas, it is necessary to ensure that agreement is achieved between laboratories on the assignment of strains to 'susceptible' and 'resistant' categories. An international quality assessment study, involving 15 laboratories in eight countries, was performed to investigate the standard of performance of the susceptibility testing of Haemophilus influenzae. One hundred and fifty strains of H. influenzae were distributed from the London Hospital Medical College (LHMC) to all laboratories who were asked to test the susceptibility of the strains to ampicillin, chloramphenicol, tetracycline, trimethoprim, cephalosporins and ciprofloxacin. Laboratories were also asked to provide the details of methodology to test the susceptibility. Significant discrepancy between the LHMC and the participating laboratories appeared in the detection of resistance to ampicillin (especially beta-lactamase-negative strains resistant to ampicillin) as well as the assignment of susceptibility and resistance to chloramphenicol, tetracycline and trimethoprim. Often these reflected the use of inappropriate breakpoints which led to erroneous assignment of susceptibility. Other variations including disc content, medium and supplement, inoculum as well as failure to measure zone sizes properly also led to some repeating anomalies.

Ampicillin↗
PubMed1996

Apoptosis of monocytes and prolonged survival of granulocytes as a result of phagocytosis of bacteria.

Monocytes and granulocytes were incubated with suspensions of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, or Salmonella enteritidis and, after being washed free of bacteria, cultured for up to 48 h. Every few hours, samples of cultured cells were taken for DNA isolation. Monocytes which phagocytosed bacteria showed features of apoptotic cells, as determined by light microscopy and DNA fragmentation detected by gel electrophoresis. The phenomenon was observed 2 to 4 h after phagocytosis, in contrast, control monocytes did not show signs of apoptosis until 48 h of culture. Intact control granulocytes spontaneously became apoptotic after 12 h of culture. In contrast, degradation of DNA in cells exposed to bacteria was delayed by 12 to 24 h. In conclusion, our observation suggests that granulocytes and monocytes react differently to phagocytosis of bacteria.

Apoptosis↗
PubMed1996

Phenotyping methods in epidemiological analysis of epidemic Staphylococcus aureus strains.

One hundred and fifty hospital Staphylococcus aureus strains isolated on Polish hospitals during an outbreaks were used to evaluate usefulness of S. aureus phenotyping methods. According to the expression of resistance to methicillin (a marker of resistance to all beta-lactam antibiotics) all strains were classified as homogeneously of heterogeneously resistant to methicillin (methicillin resistant S. aureus--MRSA) and as susceptible to this antibiotic (methicillin-susceptible S. aureus--MSSA). All strains were analysed according to the resistance patterns to fifteen antistaphylococcal drugs, results of crystal violet test, phage patterns and results of biochemical fingerprinting by PhenePlate (PhP) System (BioSys inova). All MSSA analysed were resistant to penicillin and 22% to tetracycline, and only occasionally resistant to other antimicrobials. They showed sensitive to phages of all international and additional lytic groups. Heterogeneous MRSA were widely susceptible to almost all antimicrobials except tetracycline and were lysed by phages of Ist, IIIrd international groups and additional phages. All these strains produced penicillinases. Homogeneous MRSA were multi-drug resistant and were not typable by phages of Ist and IInd lytic groups and weakly typable by phages of IIIrd and additional groups. PhP Systems divided all used strains into 13 common (with two dominating) and 50 single strain PhP-types. The combination of various phenotyping methods may be useful in epidemiological investigation of hospitals.

Anti-Bacterial Agents↗
PubMed1994

Characterization of two different clusters of clonally related methicillin-resistant Staphylococcus aureus strains by conventional and molecular typing.

The DNA fragments of 28 distinct isolates of methicillin-resistant Staphylococcus aureus (MRSA) originating from different hospitals in Warsaw and Lodz, were studied. They were obtained by cleavage with restriction endonuclease SmaI and subsequently analysed by pulsed-field electrophoresis. Sixteen different patterns were seen and clusters of related strains were clearly distinguishable. Minor differences in fragment patterns within these clusters and among epidemiologically related strains, revealed genomic rearrangements in the course of clonal dissemination of particular strains. The isolates were also checked for the expression of methicillin resistance. Isolates with heterogenous and homogeneous phenotypes, fell into clearly distinct clusters and thus formed two clonally related MRSA strains. Differences were also seen with phage and biochemical typing, and antimicrobial resistance patterns.

Bacterial Typing Techniques↗