Acta microbiologica Polonica最新文献

Siderophore activity as the feature of microorganisms enabling colonization of human body and the survival in inanimate environment was investigated in 108 strains of Staphylococcus cohnii; S. cohnii ssp. cohnii (50 strains) and S. cohnii ssp. urealyticus (58 strains). Strains were isolated from people, hospital and non-hospital environment. Highest siderophore activity was noted in strains S. cohnii ssp. urealyticus particularly from the inanimate environments origin. In 86% analyzed strains siderophores of hydroxamate class were detected. Larger amounts of these compounds were synthesized in strains S. cohnii ssp. urealyticus. Strains belonging to both subspecies from human origin showed lower activity of siderophores (total pool) and did not produce hydroxamate class chelators or produced very small amounts of these compounds.

Many different foodborne diseases have been described. For example, Shigella bacteria, hepatitis A virus and Norwalk virus were shown as a unwashed hands microorganisms, but pathogen Campylobacter and Escherichia coli were named as raw and undercooked meat and poultry or raw milk and untreated water born bacteria. However, two of them: Listeria monocytogenes and Yersinia enterocolitica are known as growing at refrigerator temperatures. Essential virulence determinants of Listeria monocytogenes pathogenicity are well known as a bacterial toxins. Basic molecular mechanisms of pathogenicity depending from these toxins were presented. It was shown that other bacterial toxins may act as very danger food poisoning substances. This is why elimination of pathogenic microorganisms from foods is an obvious solution in some food processes, however this approach is not practical or even desirable in many processes. Thus, risk assessment and microbial monitoring will continue to play important roles in ensuring food safety. Some technological advances have the capability of delivering detection systems that can not only monitor pathogenic microorganisms, but also entire microbial populations in the food matrix.

The distribution of different genotypes of Yersinia enterocolitica strains recovered from humans and from healthy pigs was investigated using PCR fingerprinting. The thirty six strains of Y. enterocolitica from humans, thirty five strains from pigs and Y. enterocolitica ATCC 9610 strain were included in this study. The tested strains of Y. enterocolitica belonged to O3 and O9 serogroups. The PCR fingerprinting using EAE5 primer (5' CTT AAT CTC AGT AAT GCT GGC CTT GG) made it possible to form five groups among the tested Y. enterocolitica strains. Two groups were very numerously represented by the tested strains. The thirty of Y. enterocolitica O3 strains from humans (thirty one of tested) and eighteen of Y. enterocolitica O3 strains from pigs (twenty of tested) belonged to one group. This group also included Y. enterocolitica ATCC9610 strain and four Y. enterocolitica O9 strains from pigs. All investigated Y. enterocolitica O9 strains from humans and the majority of Y. enterocolitica O9 strains isolated from pigs created a second, numerous group. The third genotype was created by two strains O9 from pigs, and the remaining two strains, isolated from pigs, belonging to O3 and O9 serogroups showed different binding patterns revealed by gel electrophoresis and created two other genotypes. The tested Y. enterocolitica strains which were isolated from humans formed only two groups but Y. enterocolitica strains isolated from pigs were found in five groups but such as the Y. enterocolitica strains from humans, the majority of strains from pigs were in first and second group. The Y. enterocolitica O3 strains regardless of their origin mostly represented the same PCR fingerprinting profile. The tested Y. enterocolitica O9 strains were more genetically diverse and represented four PCR fingerprinting profiles.

The aim of this study was to evaluate adherence of 83 strains of Pseudomonas aeruginosa isolated from humans and different animals to trypsin-treated buccal cells. We have demonstrated that Pseudomonas aeruginosa attached to trypsin-treated buccal cells in far greater numbers than to cells from controls (normal buccal epithelial cells). The mean number of bacteria adhering to trypsin-treated cells amounted 107.05 +/- 102.16 and to normal cells - 6.97 +/- 3.53. We conclude that exposure of cells to proteolytic enzymes increases Pseudomonas aeruginosa binding to buccal cells.

In this paper the ecological aspects of widespread antibiotic consumption are described. Many practitioners, veterinarians, breeders, farmers and analysts work on the assumption that a antibiotics undergo spontaneous degradation. It is well documented that the indiscriminate use of antibiotics has led to the water contamination, selection and dissemination of antibiotic-resistant organisms, alteration of fragile ecology of the microbial ecosystems. The damages caused by the overuse of antibiotics include hospital, waterborne and foodborne infections by resistant bacteria, enteropathy (irritable bowel syndrome, antibiotic-associated diarrhea etc.), drug hypersensitivity, biosphere alteration, human and animal growth promotion, destruction of fragile interspecific competition in microbial ecosystems etc. The consequences of heavy antibiotic use for public and environmental health are difficult to assess: utilization of antibiotics from the environment and reduction of irrational use is the highest priority issue. This purpose may be accomplished by bioremediation, use of probenecid for antibiotic dosage reduction and by adoption of hospital infections methodology for control resistance in natural ecosystems.

Phlebia radiata formed extracellular alpha-galactosidase when it was grown in a culture containing wheat bran or locus bean gum as a carbon source. Their activities were optimal at pH 5.0, and demonstrated the highest level of activity at 60 degrees C. Highly purified isoforms of alpha-galactosidase (AGaS-m1, AGaS-m2, AGaS-m3) isolated from the media with galactomannan and (AGaS-b1, AGaS-b2, AGaS-b3) from the media with wheat bran were obtained by means of the column chromatography on Q-Sepharose and chromatofosussing on Polybuffer Exchanger PBE-94.

The production of rifamycins B and SV using glucose as main C-source by Amycolatopsis mediterranei in batch and fed-batch culture was investigated. Fed-batch culture using glucose as mono feeding substrate either in the form of pulse addition, in case of shake flask, or with constant feeding rate, in bioreactor level, proved to be an alternative production system with a significant increase in both volumetric and specific antibiotic production. The maximal concentrations of about 1146 mg/l and 2500 mg/l of rifamycins B and SV, respectively, was obtained in fed-batch culture in bioreactor level under non-oxygen limitation. On the other hand, the rate of rifamycins production was increased from 6.58 to 12.13 mg/l x h for rifamycin B and from 9.47 to 31.83 mg/l x h for rifamycin SV on the bioprocess transfer and improvement from the conventional batch cultivation in shake flask to fed-batch cultivation in stirred tank bioreactor.

The introduction of real-time PCR technology has significantly improved and simplified the quantification of nucleic acids, and this technology has become an invaluable tool for many scientists working in different disciplines. Particularly in the field of molecular diagnostics and genotyping, real-time PCR-based assays have gained favour in the recent past. Rapid real-time PCR diagnosis can result in appropriate control measures and eradication procedures in a faster and more accurate way than traditional methods based on pathogen isolation. Real-time quantitative PCR represents a highly sensitive and powerful technique for the gel-free detection of nucleic acids. In this review, the main chemistries used for the detection of PCR product during real-time PCR, as well as advantages and limitations of real-time PCR will be depicted. Furthermore, the existing literature as it applies to plant pathogens detection in the routine and research laboratory will be reviewed in order to focus on one of the many areas in which the application of real-time PCR has provided significant methodological benefits.

Aminopeptidases are enzymes that release N-terminal amino residues from oligopeptides, polypeptides and proteins. The classification of aminopeptidases has often been based on mechanism of catalysis, structure of active site, substrate specificity kinetic and molecular properties. In terms of catalytic mechanism bacterial aminopeptidases can be divided into three main catalytic groups: metallo-, cysteine- and serine aminopeptidases. According to their substrate specificity the enzymes can be ordered into two sub-groups: having broad or narrow specificity. Almost half of the characterized aminopeptidases show a subunit structure. Enzymes having a quaternary structure are most often built of a combination of 2, 4, 6 subunits. Bacterial aminopeptidases may be localised in the cytoplasm, on membranes, associated with the envelope or secreted into the extracellular media. Regulation of the synthesis of aminopeptidases is assumed to take place mainly at the level of transcription. Most genes encoding the enzymes are monocistronic and contain a promotor characteristic for the genes transcribed by RNA polymerase associated with the factor sigma70. Aminopeptidases play an important role in the initial and final steps of protein turnover and they are involved in several specific regulatory functions.

A total of 391 respiratory isolates of Staphylococcus aureus in Sivas (Turkey) were studied between January 1999-2002. The organisms were cultured from the following specimens: throat (43%), sputum (28%), transtracheal/endotracheal aspirates (27%), and bronchial lavage (2%). The isolates were tested against 11 different antibiotics by a disk diffusion method or standardized microdilution technique. Methicillin-resistant isolates constituted 76.9% of all isolates. Most of the methicillin-resistant isolates (95.1%) were isolated from inpatients. The rate of methicillin-resistant isolates in throat, sputum, and tracheal aspirates was 17.2%, 60.1%, and 68.9%, respectively. The resistance of methicillin-resistant isolates in throat to teicoplanin was 3.4%. The methicillin-sensitive isolates were susceptible to most agents tested, while most methicillin-resistant isolates were resistant to these agents. Overall resistance to erythromycin was 61.9%, tetracycline 56.6%, gentamicin 50.7%, ofloxacin 42.0%, rifampin 40.8%, clindamycin 38.9%, chloramphenicol 19.0%, co-trimoxazole 10.2%, and vancomycin 0%.