Biomedical subjects

E M Szewczyk

Publications and source records attributed to E M Szewczyk.

5 recordsLinked to original sources

PubMed2004

Plasmids of Staphylococcus cohnii isolated from the intensive-care unit.

Numerous isolates of both subspecies of Staphylococcus cohnii were found in the environment of the intensive-care unit of a pediatric hospital. These isolates carried in their cells many plasmids, up to fourteen, of a wide range of sizes (< 2 to > 56 kb). Striking was the occurrence of large plasmids not very common in staphylococci. These were present in > 80% of S. cohnii isolates. Fifty-two different plasmid profiles were found in 79 investigated isolates belonging to S. cohnii ssp. cohnii and S. cohnii ssp. urealyticus. Isolates similar in plasmid profiles were grouped in antibiotic-resistance clusters established for 9 antibiotics (gentamicin, ciprofloxacin, clindamycin, erythromycin, tetracycline, chloramphenicol, mupirocin, trimethoprim-sulfamethoxazole, vancomycin) using the method of unweighted pair group mathematical averages (UPGMA). Many isolates were multiresistant to antibiotics and produced bacteriocins.

Anti-Bacterial Agents↗

PubMed2002

Evaluation of selected features of Staphylococcus cohnii enabling colonization of humans.

Based on iron utilization, sensitivity to skin fatty acids, lipolytic and proteolytic activity the potential abilities of Staphylococcus cohnii strains to colonize humans were evaluated. The investigation included 60 strains that belong to both subspecies, viz. S. cohnii ssp. cohnii and S. cohnii ssp. urealyticus. Strains were isolated from different sources of the Intensive Care Unit and from non-hospital environment. Most of the strains were multiple antibiotic-resistant. Strains of both subspecies revealed a relatively low iron requirement. These strains were capable of utilizing iron bound in oxo acids and from host iron-binding proteins. S. cohnii ssp. urealyticus were more effective in iron uptake than S. cohnii ssp. cohnii. All investigated strains revealed sensitivity to skin fatty acids, but S. cohnii ssp. urealyticus strains were more resistant. Special features of strains of this subspecies promote colonization of humans.

Anti-Bacterial Agents↗

PubMed2000

Predominant staphylococci in the intensive care unit of a paediatric hospital.

Coagulase-negative staphylococci cause a significant number of infections, especially in immunocompromised patients, including premature neonates. Nosocomial strains present in the environment create a special risk.We studied staphylococci isolated from the intensive care unit of a paediatric teaching hospital over the period of six months in 1997. Biotyping and species identification were performed; resistance to methicillin and other beta-lactam antibiotics and patterns of resistance to antimicrobial agents were determined. Staphylococcus cohnii was the predominant species of 147 isolates of staphylococci recovered from the ward environment. Strains were resistant to several antibiotics and 97% were resistant to methicillin. In isolates from infants (72) methicillin-resistant strains of Staphylococcus epidermidis were predominant. Susceptibility to beta-lactams (penicillin, amoxycillin, amoxycillin-clavulanic acid and cephalosporins: cephalothin, cefuroxime and cefotaxime) showed differences between the two species. Some S. cohnii were susceptible to penicillin and amoxycillin despite methicillin-resistance. S. epidermidis were relatively susceptible to amoxycillin-clavulanic acid and cephalosporins. All strains investigated were susceptible to vancomycin, but nearly 30% demonstrated high-level resistance to mupirocin. The search for strains of the same origin showed clones belonging to S. epidermidis, S. hominis and S. saprophyticus but not S. cohnii.A large number of multiresistant, phenotypically different S. cohnii strains surviving in the ward environment may provide a reservoir of antimicrobial resistance genes.

Bacterial Typing Techniques↗

PubMed2000

Staphylococcus cohnii--resident of hospital environment: cell-surface features and resistance to antibiotics.

Staphylococcus cohnii strains dominated in the environment of investigated hospitals. We isolated 420 strains of the species mainly from hospitals environments, but also from infants--Intensive Care Units patients, its medical staff and non-hospital environments. S. cohnii subspecies cohnii was seen to dominate (361 strains). Seventy seven percent of these strains expressed cell-surface hydrofobicity, most of them were slime producers (61%) and this feature was correlated with their methicillin resistance. Among S. cohnii ssp. cohnii strains isolated from ICU environment 90% were resistant to methicillin, 43% expressed high-level resistance to mupirocin and high percentages were resistant to many other antibiotics. These strains may constitute a dangerous reservoir of resistance genes in a hospital.

Drug Resistance, Microbial↗

PubMed1992

Poly-beta-hydroxybutyrate in staphylococci.

Staphylococci--chemoorganotrophic bacteria whose main habitats are human and animal organisms--can accumulate poly-beta-hydroxybutyrate (PHB) in their cells. The polymer is metabolized in endogenous turnovers preceding degradation of aminoacids, proteins and RNA. PHB depolymerase was not found in staphylococci but beta-hydroxybutyrate dehydrogenase was estimated, purified and characterized.

Hydrogen-Ion Concentration↗