Colonization of methicillin-resistant Staphylococcus species in healthy and sick pets: prevalence and risk factors.

BACKGROUND: The characterization of staphylococcal species that colonize pets is important to maintain animal health and to minimize the risk of transmission to owners. Here, the prevalence of Staphylococcus spp. and methicillin resistance was investigated in canine and feline isolates, and risk factors of staphylococcal colonization were determined. Pets were examined and separated into four groups: (1) healthy dogs, (2) healthy cats, and (3) dogs and (4) cats with clinical signs of bacterial infections of skin, mucous membranes, or wounds. Specimens were collected by a veterinary physician from six anatomic sites (external ear canal, conjunctival sacs, nares, mouth, skin [groin], and anus). In total, 274 animals (cats n = 161, dogs n = 113) were enrolled. RESULTS: Staphylococcus species were highly diverse (23 species; 3 coagulase-positive and 20 coagulase-negative species), with the highest variety in healthy cats (19 species). The most frequent feline isolates were S. felis and S. epidermidis, while S. pseudintermedius was the most prevalent isolate in dogs. Risk factors of staphylococcal colonization included the presence of other animals in the same household, medical treatment within the last year, and a medical profession of at least one owner. Methicillin resistance was higher in coagulase-negative (17.86%) compared to coagulase-positive (1.95%) staphylococci. The highest prevalence of methicillin-resistant CoNS colonization was observed in animals kept in homes as the most common (dogs and cats). CONCLUSIONS: The association of methicillin-resistant CoNS colonization with animals most often chosen as pets, represents a high risk of transmission between them and owners. The importance of nosocomial transmission of CoNS was also confirmed. This information could guide clinical decisions during the treatment of veterinary bacterial infections. In conclusion, the epidemiologic characteristics of CoNS and their pathogenicity in pets and humans require further research.

The Phylogenetic Structure of Reptile, Avian and Uropathogenic Escherichia coli with Particular Reference to Extraintestinal Pathotypes.

The impact of the Gram-negative bacterium Escherichia coli (E. coli) on the microbiomic and pathogenic phenomena occurring in humans and other warm-blooded animals is relatively well-recognized. At the same time, there are scant data concerning the role of E. coli strains in the health and disease of cold-blooded animals. It is presently known that reptiles are common asymptomatic carriers of another human pathogen, Salmonella, which, when transferred to humans, may cause a disease referred to as reptile-associated salmonellosis (RAS). We therefore hypothesized that reptiles may also be carriers of specific E. coli strains (reptilian Escherichia coli, RepEC) which may differ in their genetic composition from the human uropathogenic strain (UPEC) and avian pathogenic E. coli (APEC). Therefore, we isolated RepECs (n = 24) from reptile feces and compared isolated strains' pathogenic potentials and phylogenic relations with the aforementioned UPEC (n = 24) and APEC (n = 24) strains. To this end, we conducted an array of molecular analyses, including determination of the phylogenetic groups of E. coli, virulence genotyping, Pulsed-Field Gel Electrophoresis-Restriction Analysis (RA-PFGE) and genetic population structure analysis using Multi-Locus Sequence Typing (MLST). The majority of the tested RepEC strains belonged to nonpathogenic phylogroups, with an important exception of one strain, which belonged to the pathogenic group B2, typical of extraintestinal pathogenic E. coli. This strain was part of the globally disseminated ST131 lineage. Unlike RepEC strains and in line with previous studies, a high percentage of UPEC strains belonged to the phylogroup B2, and the percentage distribution of phylogroups among the tested APEC strains was relatively homogenous, with most coming from the following nonpathogenic groups: C, A and B1. The RA-PFGE displayed a high genetic diversity among all the tested E. coli groups. In the case of RepEC strains, the frequency of occurrence of virulence genes (VGs) was lower than in the UPEC and APEC strains. The presented study is one of the first attempting to compare the phylogenetic structures of E. coli populations isolated from three groups of vertebrates: reptiles, birds and mammals (humans).

Cloacal Gram-Negative Microbiota in Free-Living Grass Snake Natrix natrix from Poland.

Reptiles appear to be an important vector for Gram-negative pathogens, therefore, they are epidemiologically relevant. However, the composition of reptilian microbiota has been poorly recognized so far. The majority of studies concern exotic reptiles as asymptomatic carriers of Salmonella serovars. Studies of other intestinal bacteria of reptiles are rare. Only recently, the microbiota of free-living European reptiles have been investigated, however, on the basis of small samples, mainly in protected areas. Here, we aim to investigate cloacal Gram-negative microbiota of free-living Natrix natrix. Snakes (N = 45) used in the study were collected in Kraków (Poland) and its vicinity. Nineteen species of Gram-negative bacteria were isolated. The most common species were: Aeromonas hydrophila, Morganella morganii, Proteus vulgaris, Salmonella spp. The bacteria prevalent in N. natrix cloacal swabs are likely to represent the natural intestinal Gram-negative microbiota of the examined snakes. Importantly, the identified bacteria are pathogenic to humans, which clearly highlights the epidemiological potential of free-living N. natrix. The risk of infection is high for immunocompromised humans, children (under 5 years old), elderly persons, and pregnant women. Our study provides the largest dataset on intestinal Gram-negative microbiota of wild snakes. The presence of multiple human pathogens determined by us calls for the necessity of further studies on reptile-transmitted bacteria in anthropogenic environments.

Molecular Routes to Specific Identification of the Lactobacillus Casei Group at the Species, Subspecies and Strain Level.

The genus Lactobacillus includes, among others, Lactobacillus casei, Lactobacillus paracasei and Lactobacillus rhamnosus, species that are collectively referred to as the Lactobacillus casei group. Many studies have shown that strains belonging to this group may decrease lactose intolerance, the effects of inflammatory bowel disease, diarrhea, constipation, food allergies and even colon cancer. Moreover, evidences exists of positive effects of these bacteria on mucosal immunity and blood cholesterol level. Because of their beneficial influence on human health, many of them are used as food additives and probiotic pharmaceuticals. It should be stressed that health-promoting properties are not attributed at the species level, but to specific strains. Therefore, procedures are necessary to allow specific identification at each phylogenetic level-genus, species and strain. In this paper we present a practical overview of molecular methods for the identification and differentiation of L. casei bacteria. The research included 30 bacterial strains belonging to three species: L.casei, L. paracasei and L. rhamnosus. Among the tested procedures were genus- and species-specific PCR, multiplex-PCR, Real-Time HRM analysis, RFLP-PCR, rep-PCR, RAPD-PCR, AFLP-PCR, and proteomic methods such as MALDI-TOF MS typing and SDS-PAGE fingerprinting. The obtained results showed that multiplex-PCR and MALDI-TOF MS turned out to be the most useful methods to identify the tested bacteria at the species level. At the strain level, the AFLP-PCR method showed the highest discriminatory power. We hope that the presented results will allow for the easy selection of an appropriate procedure, depending on the experiment conducted and the equipment capabilities of any given laboratory.

Comparison of the phylogenetic analysis of PFGE profiles and the characteristic of virulence genes in clinical and reptile associated Salmonella strains.

BACKGROUND: Salmonella is generally considered as a human pathogen causing typhoid fever and gastrointestinal infections called salmonellosis, with S. Enteritidis and S. Typhimurium strains as the main causative agents. Salmonella enterica strains have a wide host array including humans, birds, pigs, horses, dogs, cats, reptiles, amphibians and insects. Up to 90% of reptiles are the carriers of one or more serovars of Salmonella. Extraintestinal bacterial infections associated with reptiles pose serious health threat to humans. The import of exotic species of reptiles as pet animals to Europe correlates with the emergence of Salmonella serotypes, which not found previously in European countries. The presented study is a new report about Salmonella serotypes associated with exotic reptiles in Poland. The goal of this research was to examine the zoonotic potential of Salmonella strains isolated from reptiles by comparative analysis with S. Enteritidis strains occurring in human population and causing salmonellosis. RESULTS: The main findings of our work show that exotic reptiles are asymptomatic carriers of Salmonella serovars other than correlated with salmonellosis in humans (S. Enteritidis, S. Typhimurium). Among the isolated Salmonella strains we identified serovars that have not been reported earlier in Poland, for example belonging to subspecies diarizonae and salamae. Restriction analysis with Pulsed-field Gel Electrophoresis (PFGE), showed a great diversity among Salmonella strains isolated from reptiles. Almost all tested strains had distinct restriction patterns. While S. Enteritidis strains were quite homogeneous in term of phylogenetic relations. Most of the tested VGs were common for the two tested groups of Salmonella strains. CONCLUSIONS: The obtained results show that Salmonella strains isolated from reptiles share most of virulence genes with the S. Enteritidis strains and exhibit a greater phylogenetic diversity than the tested S. Enteritidis population.

Identification of Yersinia enterocolitica isolates from humans, pigs and wild boars by MALDI TOF MS.

BACKGROUND: Yersinia enterocolitica is widespread within the humans, pigs and wild boars. The low isolation rate of Y. enterocolitica from food or environmental and clinical samples may be caused by limited sensitivity of culture methods. The main goal of present study was identification of presumptive Y. enterocolitica isolates using MALDI TOF MS. The identification of isolates may be difficult due to variability of bacterial strains in terms of biochemical characteristics. This work emphasizes the necessity of use of multiple methods for zoonotic Y. enterocolitica identification. RESULTS: Identification of Y. enterocolitica isolates was based on MALDI TOF MS, and verified by VITEK® 2 Compact and PCR. There were no discrepancies in identification of all human' and pig' isolates using MALDI TOF MS and VITEK® 2 Compact. However three isolates from wild boars were not decisively confirmed as Y. enterocolitica. MALDI TOF MS has identified the wild boar' isolates designated as 3dz, 4dz, 8dz as Y. enterocolitica with a high score of matching with the reference spectra of MALDI Biotyper. In turn, VITEK® 2 Compact identified 3dz and 8dz as Y. kristensenii, and isolate 4dz as Y. enterocolitica. The PCR for Y. enterocolitica 16S rDNA for these three isolates was negative, but the 16S rDNA sequence analysis identified these isolates as Y. kristensenii (3dz, 4dz) and Y. pekkanenii (8dz). The wild boar' isolates 3dz, 4dz and 8dz could not be classified using biotyping. The main bioserotype present within pigs and human faeces was 4/O:3. It has been shown that Y. enterocolitica 1B/O:8 can be isolated from human faeces using ITC/CIN culturing. CONCLUSION: The results of our study indicate wild boars as a reservoir of new and atypical strains of Yersinia, for which protein and biochemical profiles are not included in the MALDI Biotyper or VITEK® 2 Compact databases. Pigs in the south-west Poland are the reservoir for pathogenic Y. enterocolitica strains. Four biochemical features included in VITEK® 2 Compact known to be common with Wauters scheme were shown to produce incompatible results, thus VITEK® 2 Compact cannot be applied in biotyping of Y. enterocolitica.

Re-classification within the serogroups O3 and O8 of Citrobacter strains.

BACKGROUND: Citrobacter strains are opportunistic pathogens often responsible for serious enteric as well as extra-intestinal diseases, and therefore the O-antigenic scheme, still in use in diagnostic identification, should be set for proper serotyping. The structures of more than 30 different Citrobacter O-antigens (O-polysaccharide chains of the lipopolysaccharides) of 43 Citrobacter O-serogroups have been elucidated so far. However, relationships between strains in several heterogeneous serogroups still need to be clarified by immunochemical studies. These include complex serogroups O3 and O8, represented by 20 and 7 strains, respectively, which are the subject of the present work. Earlier, the O-polysaccharide structures have been determined for Citrobacter O3 strain Be35/57 (PCM 1508) and Citrobacter O8 strain Be64/57 (PCM 1536). RESULTS: Serological studies (immunoblotting) carried out on Citrobacter lipopolysaccharides from different strains ascribed to serogroups O3 and O8 showed that each of these serogroups should be divided into non-cross-reacting subgroups. Based on the results of chemical analyses and 1H and 13C NMR spectroscopy the structure of Citrobacter O-antigens from strains PCM 1504 (O6) and PCM 1573 (O2) have been established. Chemical data combined with serological analyses showed that several Citrobacter strains should be reclassified into other serogroups. CONCLUSIONS: Immunochemical studies carried out on Citrobacter LPS, described in this paper, showed the expediency of reclassification of: 1) strains PCM 1504 and PCM 1573 from serogroups O6 and O2 to serogroups O3 and O8, respectively, 2) strains PCM 1503 and PCM 1505 from serogroups O3 and O8 to new serogroups O3a and O8a, respectively.

Elizabethkingia miricola as an opportunistic oral pathogen associated with superinfectious complications in humoral immunodeficiency: a case report.

BACKGROUND: Elizabethkingia miricola is a rare Gram-negative bacterium found in water and clinical specimens. Typical culturing methods often misidentify Elizabethkingia spp. as Flavobacterium or Chryseobacterium. Although diagnosis is based on culturing samples taken from sterile sites, such as blood, a proper identification of this bacterium requires an expertise that goes beyond the capabilities of a typical clinical laboratory. CASE PRESENTATION: A 35-year-old woman diagnosed with common variable immunodeficiency was admitted to our center. Previous treatment with antibiotics (amoxicillin plus clavulanate, first and third generation of cephalosporins, macrolides) and systemic corticosteroids (up to 120 mg/day of prednisolone) failed to arrest the spread of inflammation. Gingival recession was observed in her oral cavity, resulting in an apparent lengthening of her teeth. In addition to typical commensal bacteria, including streptococci and neisseriae, strains of Rothia mucilaginosa and Elizabethkingia miricola were identified upon a detailed microbiological examination using a MALDI-TOF MS Biotyper system. The presence of the latter strain correlated with severe periodontitis, lack of IgA in her saliva and serum, a very low IgG concentration (< 50 mg/dl), IgM-paraproteinemia, decreases in C3a and C5a and microvascular abnormality. High-dose immunoglobulin (to maintain IgG > 500 mg/dl) and targeted levofloxacin treatment resulted in immune system reconstitution, oral healing, and eradication of the Elizabethkingia infection. CONCLUSIONS: E. miricola rarely causes disease in healthy individuals. However, the overgrowth of commensal bacteria, lack of IgG/IgA, microvasculopathy and complement cascade activation in patients with humoral immunodeficiency may facilitate Elizabethkingia invasion. Overuse of antibiotics, particularly beta-lactams, may cause mucosal colonization by E. miricola, followed by its multiplication combined with periodontitis that prompts bacterial translocation. MALDI-TOF Biotyper analysis may become a method of choice for identification of Elizabethkingia infections.

Application of Routine Diagnostic Procedure, VITEK 2 Compact, MALDI-TOF MS, and PCR Assays in Identification Procedure of Bacterial Strain with Ambiguous Phenotype.

In diagnostic microbiology as well as in microbiological research, the identification of a microorganism is a crucial and decisive stage. A broad choice of methods is available, based on both phenotypic and molecular properties of microbes. The aim of this study was to compare the application of phenotypic and molecular tools in bacterial identification on the example of Gram-negative intestine rod with an ambiguous phenotype. Different methods of identification procedure, which based on various properties of bacteria, were applied, e.g., microscopic observation of single-bacterial cells, macroscopic observation of bacterial colonies morphology, the automated system of microorganism identification (biochemical tests), the mass spectrometry method (analysis of bacterial proteome), and genetic analysis with PCR reactions. The obtained results revealed discrepancies in the identification of the tested bacterial strain with an atypical phenotype: mucous morphology of colonies, not characteristic for either E. coli and Citrobacter spp., mass spectrometry analysis of proteome initially assigned the tested strain to Citrobacter genus (C. freundii) and biochemical profiles pointed to Escherichia coli. A decisive method in the current study was genetic analysis with PCR reactions which identified conserved genetic sequences highly specific to E. coli species in the genome of the tested strain.

Detection of ureolytic activity of bacterial strains isolated from entomopathogenic nematodes using infrared spectroscopy.

The pathogenicity of entomopathogenic nematodes (EPNs) depends directly on the presence of bacteria in the nematode digestive tracts. Based on 16S rRNA and MALDI-TOF analyses 20 isolated bacteria were assigned to 10 species with 10 isolates classified as Pseudomonas ssp. Six strains (30%) show ureolytic activity on Christensen medium. Spectroscopic analysis of the strains showed that the ureolytic activity is strongly correlated with the following wavenumbers: 935 cm(-1) in window W4, which carries information about the bacterial cell wall construction and 1158 cm(-1) in window W3 which corresponds to proteins in bacterial cell. A logistic regression model designed on the basis of the selected wavenumbers differentiates ureolytic from non-ureolytic bacterial strains with an accuracy of 100%. Spectroscopic studies and mathematical analyses made it possible to differentiate EPN-associated Pseudomonas sp. strains from clinical Pseudomonas aeruginosa PAO1. These results suggest, that infrared spectra of EPN-associated Pseudomonas sp. strains may reflect its adaptation to the host.

Application of the MALDI-TOF for identification of Clostridium perfringens strains.

INTRODUCTION: The anaerobic bacilli Closfridium perfringens are commonly found in soil and sewage and are also part of the gastrointestinal tract of humans and animals. Food poisoning caused by C. perfringens are regarded the most common diseases transmitted by contaminated food in the world. Bacteria of this species due to their pathogenic properties sustain the constant object of studies in order to elucidate mechanisms of toxinogenesis, to determine the roads of transmission and to develop better diagnostic tools. The objective of the study was to verify, the suitability of the MALDI-TOF method for the identification of C. perfringens species. METHODS: In order to identify anaerobic bacteria C. perfringens MALDI-TOF method, sequencing of 16S rRNA and detection of cpe and cpa gene by duplex PCR were used. RESULTS: MALDI-TOF confirmed C. perfringens identification in 39 isolates out of 41 archival isolates under study. The correctness of the results was verified by 16S rRNA sequencing and cpa gene detection. CONCLUSIONS: The study confirmed the usefulness of MALDI-TOF method in rapid identi- fication of anaerobic bacteria C. perfringens and thereby its applicability epidemiological investigations.

Antifungal Susceptibility of Saccharomyces cerevisiae Isolated from Clinical Specimens.

(1) Background: Despite being considered a non-pathogenic yeast, recently, a growing occurrence of Saccharomyces cerevisiae infections has been noted. There is little knowledge about the drug susceptibility of this species. Therefore, the objective of this research was to expand it and determine the drug susceptibility profile of a local collection of clinical isolates of this species. (2) Methods: This study contained 55 clinical isolates identified as Saccharomyces cerevisiae using the MALDI-TOF method. The susceptibility of Saccharomyces cerevisiae was tested to 10 antifungals (amphotericin B, flucytosine, fluconazole, voriconazole, posaconazole, micafungin, anidulafungin, caspofungin, and itraconazole) using MICRONAUT-AT tests and manogepix, a new drug, using the microdilution method according to EUCAST. (3) Results: Overall, most strains were classified as sensitive to amphotericin B and flucytosine (MIC ranges of ≤0.03-1 and ≤0.06-0.125, respectively) and also to echinocandins. However, five isolates expressed high MIC values for all of the tested azoles, indicating cross-resistance. The MIC range for manogepix was 0.001-0.125 mg/L, with an MIC50 of 0.03 mg/L and an MIC90 of 0.06 mg/L. (4) Conclusions: The occurrence of resistance to azoles may be a concerning problem and therefore should be investigated further. However, the new antifungal manogepix appears to be an interesting new therapeutic option for treating such infections.

Red foxes (Vulpes vulpes) as a specific and underappreciated reservoir of resistant and virulent coagulase-positive Staphylococcus spp. strains.

The aim of the study was to analyze the presence of coagulase-positive Staphylococcus in swabs collected from red foxes and to characterize the drug resistance and virulence of these bacteria. In total, 415 rectal and oral swabs were collected, and coagulase-positive strains of S. pseudintermedius (n = 104) and S. aureus (n = 27) were identified using multiplex-PCR and MALDI TOF MS. Subsequent analyses showed the highest phenotypic resistance of the strains to penicillin (16.8%) and tetracycline (30.5%) confirmed by the presence of the blaZ, tetM, and tetK genes. Slightly lower resistance to erythromycin (6.9%), clindamycin (9.2%), gentamicin, streptogramins, rifampicin, nitrofurantoin, and sulphamethoxazol/trimetophrim was exhibited by single strains. Several virulence genes in a few different combinations were detected in S. aureus; LukE-LukD, and seB were the most frequent genes (37%), LukE-LukD, seB, and seC were detected in 11% of the strains, and PVL, etA, etB, and tst genes were present in two or single strains. The results of our research have confirmed that the red fox is an underestimated reservoir of coagulase-positive Staphylococcus strains, with approximately 50% of carriers of at least one resistance gene. In turn, 88.8% of the S. aureus strains had one or more virulence genes; therefore, this species of wildlife animals should be monitored as part of epidemiological surveillance.

Virulence factors of Salmonella spp. isolated from free-living grass snakes Natrix natrix.

Salmonellosis associated with reptiles is a well-researched topic, particularly in China and the United States, but it occurs less frequently in Europe. The growth of the human population and changes in the environment could potentially increase the interaction between humans and free-living reptiles, which are an unidentified source of Salmonella species. In this study, we sought to explore this issue by comparing the microbiota of free-living European grass snakes, scientifically known as Natrix natrix, with that of captive banded water snakes, or Nerodia fasciata. We were able to isolate 27 strains of Salmonella species from cloacal swabs of 59 N. natrix and 3 strains from 10 N. fasciata. Our findings revealed that free-living snakes can carry strains of Salmonella species that are resistant to normal human serum (NHS). In contrast, all the Salmonella species strains isolated from N. fasciata were sensitive to the action of the NHS, further supporting our findings. We identified two serovars from N. natrix: Salmonella enterica subspecies diarizonae and S. enterica subspecies houtenae. Additionally, we identified three different virulotypes (VT) with invA, sipB, prgH, orgA, tolC, iroN, sitC, sifA, sopB, spiA, cdtB and msgA genes, and ß-galactosidase synthesised by 23 serovars. The identification of Salmonella species in terms of their VT is a relatively unknown aspect of their pathology. This can be specific to the serovar and pathovar and could be a result of adaptation to a new host or environment.

Detection and Level Evaluation of Antibodies Specific to Environmental Bacteriophage I11mO19 and Related Coliphages in Non-Immunized Human Sera.

Bacteriophages (phages) are viruses infecting bacteria. They are widely present in the environment, food, and normal microflora. The human microbiome is a mutually interdependent network of bacteria, bacteriophages, and human cells. The stability of these tri-kingdom interactions may be essential for maintaining immunologic and metabolic health. Phages, as with each other's antigens, may evoke an immune response during a human's lifetime and induce specific antibody generation. In this manuscript, we labeled these antibodies as naturally generated. Naturally generated antibodies may be one of the most important factors limiting the efficacy of phage therapy. Herein, we attempted to determine the physiological level of these antibodies specific to a population bacteriophage named I11mO19 in human sera, using an ELISA-based assay. First, we purified the phage particles and assessed the immunoreactivity of phage proteins. Then, affinity chromatography was performed on columns with immobilized phage proteins to obtain a fraction of human polyclonal anti-phage antibodies. These antibodies were used as a reference to elaborate an immunoenzymatic test that was used to determine the level of natural anti-phage antibodies. We estimated the average level of anti-I11mO19 phage antibodies at 190 µg per one milliliter of human serum. However, immunoblotting revealed that cross-reactivity occurs between some proteins of I11mO19 and two other coliphages: T4 and ΦK1E. The antigens probably share common epitopes, suggesting that the determined level of anti-I11mO19 phage might be overestimated and reflects a group of antibodies reactive to a broad range of other E. coli phages. Anti-I11mO19 antibodies did not react with Pseudomonas bacteriophage F8, confirming specificity to the coliphage group. In this work, we wanted to show whether it is possible to determine the presence and level of anti-phage antibodies in nontargeted-immunized sera, using an immunoenzymatic assay. The conclusion is that it is possible, and specific antibodies can be determined. However, the specificity refers to a broader coliphage group of phages, not only the single phage strain.

The challenges in the identification of Escherichia coli from environmental samples and their genetic characterization.

Escherichia coli bacteria are an essential indicator in evaluations of environmental pollution, which is why they must be correctly identified. This study aimed to determine the applicability of various methods for identifying E. coli strains in environmental samples. Bacterial strains preliminary selected on mFc and Chromocult media as E. coli were identified using MALDI Biotyper techniques, based on the presence of genes characteristic of E. coli (uidA, uspA, yaiO), as well as by 16S rRNA gene sequencing. The virulence and antibiotic resistance genes pattern of bacterial strains were also analyzed to investigate the prevalence of factors that may indicate adaptation to unsupportive environmental conditions and could have any significance in further identification of E. coli. Of the strains that had been initially identified as E. coli with culture-based methods, 36-81% were classified as E. coli with the use of selected techniques. The value of Cohen's kappa revealed the highest degree of agreement between the results of 16S rRNA gene sequencing, the results obtained in the MALDI Biotyper system, and the results of the analysis based on the presence of the yaiO gene. The results of this study could help in the selection of more accurate and reliable methods which can be used in a preliminary screening and more precise identification of E. coli isolated from environmental samples.

Staphylococcus borealis - A newly identified pathogen of bovine mammary glands.

Twelve Staphylococcus borealis strains, isolated in Canada and Poland from milk of cows with intramammary infections, were characterized phenotypically (biochemical reactions on ID 32 STAPH and Biolog Phenotype MicroArrays™ PM1 and PM2A, ability of biofilm production) and genotypically (random amplified polymorphic DNA). In addition, a genomic comparison was done with S. borealis strains of human and porcine origin using the multilocus sequence typing (MLST) technique. The bovine isolates showed a high degree of phenotypic and genotypic diversity, however, they could be differentiated from human strains by the negative test for urease (found in all but one bovine isolate examined with ID 32 STAPH) and positive reaction for D-galactose (on Biolog phenotype microarray PM1) and D-lactose (on both commercial systems). The MLST method, utilizing six concatenated genes of the total length of ∼2930 bp, revealed that bovine strains (irrespective of the country of origin) show a distinctly greater degree of mutual relationship than to the strains of human and porcine origin, suggesting that S. borealis has evolved independently in these hosts. In conclusion, bovine-specific S. borealis can be involved in intramammary infections in cattle.

Biological functions of sialic acid as a component of bacterial endotoxin.

Lipopolysaccharide (endotoxin, LPS) is an important Gram-negative bacteria antigen. LPS of some bacteria contains sialic acid (Neu5Ac) as a component of O-antigen (O-Ag), in this review we present an overview of bacteria in which the presence of Neu5Ac has been confirmed in their outer envelope and the possible ways that bacteria can acquire Neu5Ac. We explain the role of Neu5Ac in bacterial pathogenesis, and also involvement of Neu5Ac in bacterial evading the host innate immunity response and molecular mimicry phenomenon. We also highlight the role of sialic acid in the mechanism of bacterial resistance to action of serum complement. Despite a number of studies on involvement of Neu5Ac in bacterial pathogenesis many aspects of this phenomenon are still not understood.

Reptiles as a source of Salmonella O48--clinically important bacteria for children: the relationship between resistance to normal cord serum and outer membrane protein patterns.

Bacteria of the Salmonella O48 somatic antigen group are clinically important strains causing intestinal dysfunction and diarrhoea, especially in children. The susceptibility of Salmonella O48 strains containing sialic acid (N-acetylneuraminic acid (NeuAc)) in lipopolysaccharide (LPS) to the bactericidal action of normal cord serum (NCS) was determined. The authors' previous results published in Microbial Ecology in 2010 indicated that neither the presence of NeuAc in LPS nor the length of the O-specific part of LPS containing NeuAc plays a decisive role in determining bacterial resistance to the bactericidal activity of normal human serum (NHS), and that the presence of NeuAc in the LPS structure is not sufficient to block the activation of the alternative pathway of complement in NHS. The current results showed that the tested strains showed various sensitivities also to the bactericidal action of NCS. The authors postulate that the presence of certain outer membrane proteins (OMPs) are characteristic of the resistant and sensitive phenotypes of Salmonella O48 strains. To establish a possible relationship between resistance to NCS and OMPs band patterns, ten Salmonella O48 strains were studied as follows: susceptibility to the bactericidal effect of NCS, the mechanisms of NCS activation and OMP band patterns obtained by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.