PubMed Health⌕ Search

Biomedical subjects

A Młynarczyk

Publications and source records attributed to A Młynarczyk.

At least 19 recordsLinked to original sources
PubMed2001

[Antibiotic resistance of Staphylococcus aureus strains isolated in two different Warsaw hospitals].

S. aureus strains isolated in the same period from different specimens obtained from patients of two different hospitals were compared. The significant differences were observed in the frequency of resistance determinants between strains of these hospitals. The most important was the difference in the prevalence of MRSA. In the first hospital the percentage of MRSA was 40% whereas in the second one only 20%. The resistance to the other antibiotics was also compared, and independently from the compared group: MRSA, MSSA or all, the prevalence of resistance determinants was higher in the first hospital than in the second. Although the frequencies of MRSA in both investigated hospitals were relatively high comparing to the other European countries and in the first hospital even alarming, isolated MRSA strains are less resistant to other antibiotics than MRSA in other countries.

Cross Infection↗
PubMed2000

[Use of PCR for evaluating detection of coa and nuc genes in methicillin-resistant, coagulase-negative strains of Staphylococcus aureus (MRSA-CN)].

Strains showing a negative reaction in tube test for coagulase constitute 10 to 20% of all Staphylococcus aureus isolated from patients of Hospital of Infant Jesus in Warsaw. Most of them are MRSA. In 42 MRSA strains showing negative reaction for coagulase, the presence of coagulase (coa) and nuclease (nucA) genes was checked. Determination of whole cell DNA with PCR reaction was performed. The obtained results revealed that all 42 strains possessed gene nucA, but only 39 strains possessed the coa gene.

Bacterial Proteins↗
PubMed2000

[Characteristics of the MRSA clone with reduced susceptibility to vancomycin].

The MIC of vancomycin was determined for all S. aureus strains isolated during 1997 in one hospital. MIC values for most isolates were in the range of 0.5-2 mg/l. In 18 strains, MIC was = 6 mg/L. All these strains were MRSA. Recently described VISA strains possessed MIC values for vancomycin equal or higher than 8 mg/l and such strains were not detected in the investigated group. Although strains with MIC = 6 mg/l are not VISA, but they are candidate for reduced vancomycin susceptibility, e.g. during therapy in compromised patients. Analysis of DNA of these strains by pulsed-field gel electrophoresis (PFGE) revealed that 15 of them shared a significant similarity, allowing to place them in the same group. The comparison data of phage patterns as well as antibiotic resistance patterns strongly suggest that all these strains were derivatives of a single clone.

DNA, Bacterial↗
PubMed1999

[Genetic transfer of methycilline resistance in Staphylococus epidermidis and Staphylococcus aureus strains in mixed cultures].

In mixed cultures of staphylococci a transfer of the resistance to methicillin and penicillinase plasmids as well as tetracycline and chloramphenicol plasmids was investigated. It was shown that the resistance to methicillin was transferred in mixed cultures from one strain of S. aureus to another and from S. epidermidis to S. aureus. In both cases transfer of methicillin resistance required, the presence of penicillinase plasmid in recipient or donor strain. In the case of other markers transmission was independent. Moreover it was shown that the transfer of resistance genes in mixed cultures was mediated by bacteriophage of the serologic group A.

Chloramphenicol↗
PubMed1999

[Use of pulse-field electrophoresis for intraspecies differentiation of methycillin-resistant, coagulase-negative strains of Staphylococcus aureus (MRSA-CN)].

Strains showing a negative reaction in tube test for coagulase accounted 10 to 20% of all Staphylococcus aureus isolated from patients of PSK No. 1 in Warsaw. They are MRSA as well as MSSA strains. 37 coagulase-negative isolates of MRSA were examined using the method depending on digestion of whole cell DNA with SmaI enzyme and electrophoretic separation of the obtained fragments in the pulsed field (PFGE). It was shown that majority of the strains (26 from 37) had individual, unique patterns of bands. However, the two groups of strains were also observed showing a great similarity. The larger group contained 8 strains which were obtained from patients from different wards and the smaller group contained 3 strains obtained from patients from one hospital ward. The obtained results showed that among coagulase-negative MRSA strains are not only sporadic strains but also strains with probably epidemic properties, derived from different clones.

Coagulase↗
PubMed1999

[Characteristics of penicillinase plasmids from Staphylococcus aureus strains].

Penicillinase plasmids are present in most MRSA strains. They are very varying in their genotype and phenotype they confer. Penicillinase plasmids were transduced from 80 hospital MRSA strains to NCTC 8325 and the phenotype as well as the incompatibility group of plasmid were determined. Resistance to cadmium (high and low level), resistance to organic and nonorganic mercury compounds, arsenate/arsenite/antimonium resistance, resistance to bismuth and hypersensitivity to bismuth, resistance to macrolides as well as beta-lactamase production and its inductibility were checked. Among the examined strains 20 different phenotypes of penicillinase plasmids were found. Patterns of penicillinase plasmids were compared to DNA patterns of the investigated strains after digestion with SmaI and separation in pulsed field electrophoresis (PFGE). It was shown that strains with the same PFGE pattern often differ in the type of their penicillinase plasmid. Determining of penicillinase plasmid phenotype could be useful in differentiating S. aureus strains sharing the same pattern of PFGE.

Drug Resistance, Microbial↗
PubMed1999

[Localization of genes conferring resistance to selected groups of antibiotics in methicillin-resistant strains of Staphylococcus aureus].

Localization of genes conferring resistance to MLS, tetracyclines, chloramphenicol, gentamycin and neomycin in 80 MRSA strains isolated from hospital specimens was determined. The obtained results were compared to DNA patterns of the examined strains after digestion with SmaI and separation in pulsed field electrophoresis (PFGE). It was shown that genes of resistance to MLS (ErmI+) in the case of 13 strains were located on chromosome and in the case of 37 strains on plasmids (16 strains had ErmI+ and 21 strains had ErmI-). Genes determining resistance to tetracyclines were localised on chromosome in the case of 39 (23 strains possessed TetK, 11 strains had TetM and 5 strains possessed both TetK and TetM determinants) and in the case of 32 strains on plasmids. Chloramphenicol resistance genes were localised on plasmids in all 30 resistant strains. Genes conferring resistance to gentamycin were present in 31 of the investigated strains on chromosome and in two strains on plasmids. Neomycin resistance genes were plasmid in 34 strains. It was shown that the localization of the resistance genes and the PFGE patterns of the investigated strains were highly correlated.

Drug Resistance, Microbial↗
PubMed1999

[Sensitivity to vancomycin and teicoplanin of coagulase-negative staphylococci isolated from clinical specimens].

The frequency of resistance and elevated resistance to teicoplanin and vancomycin among 689 strains of coagulase-negative staphylococci isolated in one year from clinical specimens was determined. Using ATB.STAPH test, a resistance was shown mainly among strains of S. epidermidis and S. haemolyticus. The elevated resistance to teicoplanin was much more frequently observed than to vancomycin. About 27% of isolated strains of S. haemolyticus and 6.8% of S. epidermidis were classified as resistant. Among other species only single strains were recognised as resistant: one strain of S. xylosus, one of S. cohni and one of S. intermedius. 94.7% of S. epidermidis and 100% of S. haemolyticus strains classified as resistant to teicoplanin in ATB showed MIC values 14 mg/l. Moreover it was shown that 26.3% of these strains of S. epidermidis and 33.3% of S. haemolyticus had MBC of teicoplanin values equal to or higher than 32 mg/l.

Coagulase↗
PubMed1998

Coagulase-negative variants of methicillin-resistant Staphylococcus aureus subsp. aureus strains isolated from hospital specimens.

At the Department of Clinical Bacteriology of Medical University of Warsaw, S. aureus strains displaying negative reactions in the coagulase tube-test were isolated with a relatively high frequency from clinical specimens. As many as seventeen of such strains all from different patients were isolated during 1994 among MRSA strains. Despite coagulase negativity all strains were positive in tests for clumping factor (CF), protein A and thermonuclease. Biochemical characteristics, phage patterns and antibiotic resistance characteristics of these strains were tested. Most of the coagulase-negative strains possessed a heterogenous type of methicillin resistance. Apart from methicillin most of them were resistant to many other antimicrobials. All were resistant to gentamicin, tetracyclines and macrolide-lincosamide-streptogramine B. An occurrence of coagulase-negative S. aureus strains may lead to problems in their identification and the necessity of an application of other methods like CF, protein A or biochemical reactions.

Bacterial Typing Techniques↗
PubMed1998

The genome of Staphylococcus aureus: a review.

The genome of Staphylococcus aureus consists of a single circular chromosome (2.7-2.8 mbp) plus an assortment of extrachromosomal accessory genetic elements: conjugative and nonconjugative plasmids, mobile elements (IS, Tn, Hi), prophages and other variable elements. Plasmids (1-60 kbp) are classified into 4 classes and there are 15 known incompatibility groups. Mobile elements of the genome (0.8-18 kbp) appear in the chromosome or in plasmids of classes II and III. Prophages (45-60 kbp) are integrated in the bacterial chromosome, and they are UV- or mitomycin-inducible. Temperate bacteriophages of S. aureus are members of the Siphoviridae and the serological groups A, B and F occur most frequently. In the paper presented, the characteristics of chromosome, plasmids, transposons and other genetic elements of S. aureus genome are given and an alphabetical list of known genes of this species is included.

Bacterial Proteins↗
PubMed1997

[Lysogenic conversion as a factor influencing tolerance to vancomycin in Staphylococcus aureus].

The standard, non-lysogenic, bacteriophage-free S. aureus NCTC 8325-4 strain was lysogenized with 15 different, obtained in our laboratory staphylokinase-converting bacteriophages belonging to serological groups A, B and F. MIC and MBC of vancomycin as well as the ratio of MBC to MIC were evaluated for all 15 lysogenic derivatives. The obtained results were compared with those for maternal strain. In the case of eight strains the ratio MBC/MIC showed the presence of tolerance to vancomycin (MBC/MIC > or = 32). Four of the vancomycin-tolerant derivatives were lysogenized with bacteriophages belonging to the serological group A, two were members of group B and two belonged to group F.

Anti-Bacterial Agents↗
PubMed1997

[Selected properties of Staphylococcus aureus strains using phenotype to show a lack of coagulase synthesis].

Eighteen of S. aureus strains isolated from clinical specimens and showing negative reaction for coagulase in conventional tube test were characterized by using five different methods: ID32 Staph, API Staph, Gpl-15, STAPH-ZYM (Rosco) and classical tube methods. The membership of all examined strains to S. aureus subsp. aureus was confirmed. None of the strains produced detectable amounts of coagulase but all of them produced protein A and clumping factor. All of them were typable with phages of the III lytic group and 11 of them possessed phage pattern characteristic of the 83A complex. All the investigated hospital strains were resistant to methicillin. Five showed homogenous and 13 heterogenous type of methicillin resistance. Moreover, all of them were resistant to tetracycline, gentamicin, tobramycin and kanamycin and to MLS group of antibiotics.

Agglutination Tests↗
PubMed1996

Epidemiology of methicillin-resistant Staphylococcus aureus in a Warsaw hospital.

Methicillin-resistant Staphylococcus aureus (MRSA) isolates were collected during two eight-month periods in 1991 and 1994, respectively. In order to study the epidemiology, all 74 strains were characterized by phage-typing, antibiotic resistance patterns and DNA-restriction map after cleavage with SmaI enzyme, and pulsed-filed gel electrophoresis (PFGE). These investigations confirmed that MRSA in the hospital, 1991 and 1994, was not due to the spread of one or two clones, but by the simultaneous occurrence of a few well characterized strains and sporadic, occurring strains of different phage-types. Some of these might have developed from the more commonly occurring strains. Isolates from 1994 were more resistant to antibiotics in vitro, than the 1991 isolates. The typing results also indicated that whilst most of the MRSA strains in 1994 were different compared with those of 1991, some of the strains might have been present in both years. The PFGE-typing was more discriminatory and gave a higher typability than the phage-typing, especially among the multiply resistant isolates of MRSA from 1994. Among the less resistant strains the phage-typability was high and with only few exceptions, there was a good correlation between PFGE-type and phage-type.

Cross Infection↗
PubMed1995

[Evaluation of susceptibility of methicillin resistant Staphylococcus aureus strains to vancomycin].

Susceptibility to vancomycin and teicoplanin was studied in the most frequently isolated Staphylococcus species isolated in the State Hospital Clinic Nr 1 in Warsaw in 1994. No strains resistant to vancomycin were found in two Staphylococci most frequently isolated from clinical material: S. aureus and S. epidermidis. Occurrence of this resistance is very rare and is restricted only to coagulase-negative Staphylococci such as S. xylosus, S. capitis, S. lentus and S. cohni. Resistance to teicoplanin was observed more often (1.4% in S. aureus and from 11.8% to 39.3% in 9 species of coagulase-negative Staphylococci). For the majority of methicillin-susceptible clinical strains (80%), the MBC value did not exceed 4.0 mcg/ml of vancomycin while for almost half of the strains in the population of methicillin-resistant strains MBC values ranged from 32.0 to 128 mcg/ml of vancomycin. Moreover, vancomycin-tolerant strains were found eight times more often in the studied MRSA (26.7%) population than in MSSA strains (3.3%).

Anti-Bacterial Agents↗
PubMed1995

[Bacteriophages of serologic group B converting synthesis of fibrinolysin in S. aureus].

On the basis of the length of tail, two morphological types of S. aureus bacteriophages of the serogroup B converting fibrinolysine were shown. The properties of the 22 S. aureus bacteriophages of the serologic group B were investigated. All of the investigated bacteriophages were classified as the morphological group II of the family Styloviridae on the basis of electron microscope analysis. The size of capsids of the examined bacteriophages was 53.85 +/- 1.05 nm and the tail length varied from 135.4 nm to 170.5 nm. All of them had the tail terminated in the basal plate. The lytic properties of the investigated bacteriophages were not identical. 7 of them showed features of lytic group I and 15 of lytic group III. The members of lytic group III had apparently a longer tail than bacteriophages of lytic group I.

Fibrinolysin↗
PubMed1995

[Bacteriophages of serologic group F converting synthesis of fibrinolysin and beta toxin in S. aureus].

The properties of the 18 S. aureus bacteriophages of the serogroup F were investigated. The chosen bacteriophages were able to convert production of fibrinolysine inhibited synthesis of beta toxin. All of the investigated bacteriophages were classified as morphological group II of the family Styloviridae on the basis of the electron microscope analysis. The size of capsids of the examined bacteriophages was 54.10 +/- 0.80 nm and the tail length was from 206.1 nm to 311.9 nm. Most of them (15 bacteriophages) had the tail terminated in the basal plate. The lytic properties of the investigated bacteriophages were not identical. 11 of them showed features of lytic group III and 7 of lytic group V (miscellaneous).

Enterotoxins↗
PubMed1993

Phage-related conversion of enterotoxin A, staphylokinase and beta-toxin in Staphylococcus aureus.

The conversion of enterotoxin A, staphylokinase and beta-toxin in Staphylococcus aureus is related with lysogeny stage. Bacteriophages able to convert enterotoxin A were used for lysogenization of the standard NCTC 8325-4 strain. Lysogenic, enterotoxigenic derivatives of this strain were characterized. The conversion of enterotoxin A was obtained in 7 examined derivatives, the conversion of enterotoxin A and staphylokinase at the same time was obtained in one case and the loss of beta hemolysin production ability was observed in all of 8 examined derivatives of the NCTC 8325-4 standard strain.

Bacterial Toxins↗