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Staphylococcus aureus colonizes the mucous membrane of the nasal vestibule of a significant number of healthy people. These microorgan-isms are opportunistic pathogens, that in favorable conditions, may cause infections of various course, location or manifestation. Second-ary infections emerge in cases when other risk factors contribute to such a change. One of the diseases during which S. aureus changes its saprophytic character to a pathogenic one is atopic dermatitis (AD), an allergic skin condition of a chronic and recurrent nature. Patients with AD are highly predisposed to secondary staphylococcal infections due to active S. aureus colonization of the stratum corneum, dam-age of the skin barrier or a defective immune response. Microorganisms present in skin lesions destroy the tissue by secreting enzymes and toxins, and additionally stimulate secondary allergic reactions. The toxins secreted by strains of S. aureus also act as superantigens and penetrate the skin barrier contributing to a chronic inflammation of the atopic skin lesions. The S. aureus species also releases proinflam-matory proteins, including enzymes that cause tissue damage. When initiating treatment it is particularly important to properly assess that the onset of the secondary bacterial infection is caused by S. aureus and thus justifying the inclusion of antibiotic therapy. Depending on the severity and extent of the staphylococcal infection, topical antibiotics are used, usually mupirocin or fusidic acid, or general antibiotic treatment is introduced. Another therapeutic strategy without antibiotics has given a positive effect in patients.
Fluorescein efflux from S. Cerevisiae cells was measured to study the peculiarities of fluorescein transport system, which is important for yeast resistance to certain drugs and weak organic acid preservatives. Glucose-independent and glucose-stimulated fluorescein effluxes were characterized using iodoacetate, cyanide and orthovanadate, inhibitors of glycolysis, electron transport chain, and ATPases, respectively. It is supposed that in glucose-free medium fluorescein extrusion is ATP-dependent and the energy for this efflux is mainly provided by respiration. In glucose-containing medium, glycolysis plays a critical role for extrusion of fluorescein. The results indicate that acetic acid inhibits the fluorescein efflux from yeast cells. The inhibition constant of glucose-stimulated fluorescein efflux is significantly lower in parental strain than in two mutants defective in PDR12 (ABC-transporter Pdr12p) or WAR1 (transcription factor of Pdr12p). It can be suggested that the membrane protein Pdr12 is involved in fluorescein extrusion from the yeast cells, but component(s) other than Pdr12p is (are) also important.
Through a CAMP test, we first observed a Staphylococcus delphini strain (ATCC 49172) to release (β-haemolysin. Production of the latter in this coagulase-positive species of the 'Staphylococcus intermedius Group', in fact, has been labeled to be undetermined, thus far. Of course, a wider number of strains have to be investigated in order to define whether this property is constitutive (like in Staphylococcus (pseud)intermedius), or strain-dependent (like in Staphylococcus aureus), and which clinical impact it has; nevertheless, we can state that S. delphini ATCC 49172 indeed produces this toxin.
We have reported a bacterial infection in a dog with progressive dysplasia of the hips. Orthopedic surgery was performed. Seven weeks prior to the surgery, the patient was bitten by another dog. The postimplantation wound exuded for four days after the surgery. Microbiological analysis performed by standard identification techniques showed the presence of Staphylococcus intermedins, but an additional molecular analysis indicated S. pseudintermedius. This was followed by an evaluation of antibiotic susceptibility of the strain which showed cefoxitin, ciprofloxacin, clindamycin, trimethoprim/sulfamethoxazole, doksycycline, erythromycin, and gentamicin resistance. Minimal inhibitory concentration (MIC) values for selected antibiotics were reported. Resistance for cefoxitin indicates that methicillin resistant S. pseudintermedius (MRSP) strains were present in individual macroorganisms, but they can expand and persist the colonization of other hosts.
To determine the staphylococcal colonization pattern in healthy and diseased dogs, living in two particular environments, a number of microbiological samples were taken. Overall, twenty dogs, either healthy or with infected skin lesions, were examined. In each case bacterial swabs were collected from the nasal mucosa, ear, perineum, lumbo-sacralis triangle, and from the infection sites if such were present. A total number of 104 isolates representing different staphylococcal species were isolated and identified using routine biochemical methods applied in diagnostic laboratories. Among 17 isolated staphylococcal species, Staphylococcus intermedius was the most common species isolated from both healthy or diseased dogs living either in animal shelter or household environments. The pattern of Staphylococcus sp. colonization differs considerably for animals living in the two tested habitats. In particular, S. aureus MRSA and MSSA isolates were detected only in infected skin lesion samples from animals that dwelled in the animal shelter. As could be expected, S. intermedius was found to be a predominant causative agent in canine skin infections. In our study, we demonstrated that S. intermedius in its carrier-state, inhabits mainly the mucosal membrane of the nasal vestibule. It was also found in the samples taken from the skin, the lumbo-sacralis triangle and perineum, but was rarely isolated from the ears.
Staphylococcus aureus is a common human and livestock opportunistic pathogen, and there is evidence of animal to human transmission.This paper aimed to recognize properties of the isolates from collections of human and livestock S. aureus strains and to estimate compat-ibility of results based on phenotypic tests, microarrays and the spa typing methods. The second goal was to study differences between human and animal isolates in terms of specificity of their hosts and the strain transmission among various hosts. Most strains showed multi-susceptible profiles and produced enzymes on a high level, and they were phenotypically and genetically similar. However, in contrast to the Polish bovine mastitis strains, the Slovakian strains were multi-resistant. In this research, the strains showed significant differences in terms of their phenotypic manifestations and the presence of hemolysins genes; however, other enzyme-encoding genes correlated to a higher extent with the microarrays results. Interestingly, there was a lack of enterotoxin genes in human Poultry-like protein A+ strains in comparison to other human strains. Our study showed that differences between virulence profiles of the human and animal strains cor-related with their origin rather than their hosts, and any trait allowed clearly distinguishing between them based on the microarray results.
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