Role of a two-component ResD-ResE system in regulating the expression of guanyl-specific ribonuclease genes in <Emphasis Type="Italic">Bacilli</Emphasis>

The role of the two-component ResD-ResE signal transduction system in regulating the expression of guanyl-specific ribonuclease genes in bacilli has been studied. Proteins with homologies to the ResD and ResE regulatory proteins of Bacillus subtilis have been found in all sequenced genomes of Bacillus. It has been shown using the B. subtilis strains defective in genes of these proteins that the ResD-ResE signal transduction system positively regulates the expression of ribonuclease genes of B. intermedius, B. pumilus, and B. thuringiensis in cells of B. subtilis. The data obtained in this work speak for the fact that regulatory system similar to the two-component ResD-ResE signal transduction system of B. subtilis also functions in other representatives of the Bacillus genus.     

A method for differentiation of <Emphasis Type="Italic">Bacillus anthracis</Emphasis> strains and phylogenetically related species based on determination of the structural differences between chromosomal genes for biosynthesis of flagellin and methionine

Nucleotide sequence analysis of several genes responsible for definitive properties of the anthrax pathogen—motility and penicillinase activity—determined a chromosomal locus promising for interspecies differentiation. We demonstrated that the fliC gene encoding flagellin synthesis contains an extended region distinguishing B. anthracis strains from the majority of nonpathogenic and opportunistic bacilli. A novel method for anthrax pathogen indication and identification based on determination of the differences in the fliC and hom2 chromosomal genes structure has been proposed. A total of 60 strains of different Bacillus spp. (B. anthracis, B. cereus, B. thuringiensis, B. mycoides, B. megaterium, B. subtilis, etc.) were tested using two chromosomal DNA targets. The algorithm developed in this work permits detection of the pathogenic microorganism and reliably differentiation of it from other Bacillus spp. representatives. The introduction of primers complementary to specific sequences of pXO1 and pXO2 plasmids into multiplex PCR makes it possible to obtain additional information on the proposed virulence of the isolate.     

Association study of <Emphasis Type="Italic">Demodex</Emphasis> bacteria and facial dermatoses based on DGGE technique

The role of bacteria is unclear in the facial skin lesions caused by Demodex. To shed some light on this issue, we conducted a case-control study comparing cases with facial dermatoses with controls with healthy skin using denaturing gradient gel electrophoresis (DGGE) technique. The bacterial diversity, composition, and principal component were analyzed for Demodex bacteria and the matched facial skin bacteria. The result of mite examination showed that all 33 cases were infected with Demodex folliculorum (D. f), whereas 16 out of the 30 controls were infected with D. f, and the remaining 14 controls were infected with Demodex brevis (D. b). The diversity analysis showed that only evenness index presented statistical difference between mite bacteria and matched skin bacteria in the cases. The composition analysis showed that the DGGE bands of cases and controls were assigned to 12 taxa of 4 phyla, including Proteobacteria (39.37–52.78%), Firmicutes (2.7–26.77%), Actinobacteria (0–5.71%), and Bacteroidetes (0–2.08%). In cases, the proportion of Staphylococcus in Firmicutes was significantly higher than that in D. f controls and D. b controls, while the proportion of Sphingomonas in Proteobacteria was significantly lower than that in D. f controls. The between-group analysis (BGA) showed that all the banding patterns clustered into three groups, namely, D. f cases, D. f controls, and D. b controls. Our study suggests that the bacteria in Demodex should come from the matched facial skin bacteria. Proteobacteria and Firmicutes are the two main taxa. The increase of Staphylococcus and decrease of Sphingomonas might be associated with the development of facial dermatoses.     

Cytotoxic and antimicrobial effects of biosynthesized ZnO nanoparticles using of <Emphasis Type="Italic">Chelidonium majus</Emphasis> extract

The basic goal of this study was to synthesize zinc oxide nanoparticles using the Chelidonium majus extract and asses their cytotoxic and antimicrobial properties. The synthesized ZnO NPs were characterized by UV-Vis, Scanning Electron Microscopy (SEM) with EDS profile, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). The aforementioned methods confirmed that the size of synthesized ZnO nanoparticles was at the range of 10 nm. The antimicrobial activity of ZnO nanoparticles synthesized using the Ch. majus extract was tested against standard strains of bacteria (Staphylococcus aureus NCTC 4163, Pseudomonas aeruginosa NCTC 6749, Escherichia coli ATCC 25922), yeast (Candida albicans ATCC 10231), filamentous fungi (molds: Aspergillus niger ATCC 16404, dermatophytes: Trichophyton rubrum ATCC 28188), clinical strains of bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus) and yeast (Candida albicans). The study showed that zinc oxide nanoparticles were excellent antimicrobial agents. What is more, biologically synthesized ZnO nanoparticles demonstrate high efficiency in treatment of human non-small cell lung cancer A549.     

Development of a method for identification and genotyping of <Emphasis Type="Italic">Pasteurella multocida</Emphasis> and <Emphasis Type="Italic">Mannheimia haemolytica</Emphasis> bacteria using polymerase chain reaction and phylogenetic analysis of bacterial cultures isolated from cattle

The results of developing the identification and genotyping method for the Pasteurella multocida bacteria of five capsule groups and the Mannheimia haemolytica A 1 bacteria, using the multiplex polymerase chain reaction (PCR) with the electrophoretic detection are reported. The diagnostic sensitivity of the developed method came to 10³ CFU/mL in the pure culture studies and 10⁵ CFU/g in the biological material studies. The analysis revealed 50% of P. multocida and 11.2% of M. haemolytica in all 260 tested samples of biological material from the infected animals. Circulation of bacteria of P. multocida capsule groups B and E among the susceptible animals was not determined. Group A bacteria were found in the majority of the samples; bacteria of group D were infrequently identified; in one case, group F bacteria were detected. The circulation of capsule group A P. multocida bacteria of two genetic types was determined using phylogenetic analysis.     

Related carbapenemase-producing <Emphasis Type="Italic">Klebsiella</Emphasis> isolates detected in both a hospital and associated aquatic environment in Sweden

Carbapenem antibiotics are one of the last-resort agents against multidrug-resistant (MDR) bacteria. The occurrence of carbapenemase-producing Enterobacteriaceae (CPE) in wastewater and aquatic environments is an indication of MDR bacteria in the community. This study evaluated CPE in aquatic environments and compared them to the local hospital isolates in Sweden. Phenotypic and genotypic analyses of antibiotic resistance of environmental and clinical CPE were performed. The relatedness of the isolates and possible clonal dissemination was evaluated using phylogenetic and phyloproteomic analysis. Klebsiella oxytoca carrying carbapenemase genes (bla_VIM-1, bla_IMP-29) were isolated from wastewater and the recipient river, while K. oxytoca (bla_VIM-1) and Klebsiella pneumoniae (bla_VIM-1, bla_OXA-48, bla_NDM-1, bla_KPC-3) were isolated from patients at the local clinics or hospital. The K. oxytoca classified as sequence type 172 (ST172) isolated from the river was genotypically related to two clinical isolates recovered from patients. The similarity between environmental and clinical isolates suggests the dispersion of bla_VIM-1 producing K. oxytoca ST172 from hospital to aquatic environment and the likelihood of its presence in the community. This is the first report of CPE in aquatic environments in Sweden; therefore, surveillance of aquatic and hospital environments for CPE in other urban areas is important to determine the major transfer routes in order to formulate strategies to prevent the spread of MDR bacteria.     

Citrulline ureidase gene diversity in the genus <Emphasis Type="Italic">Francisella</Emphasis>

This work describes the results of analysis in silico of the genetic diversity of the citrulline ureidase gene (ctu) in two species of bacteria of the genus Francisella: tularensis (ssp. tularensis, holarctica, mediasiatica, novicida) and philomiragia. The strains of the Central Asiatic subspecies possessing citrulline ureidase activity differ in the ctu gene from ssp. tularensis Schu by three nucleotide substitutions leading to two insignificant amino acid substitutions in the encoded polypeptide. In the strain of F. tularensis ssp. holarctica, the ctu gene encodes an inactive enzyme, which is probably due to amino acid substitutions 151Gly → Asp, 183Pro → Leu, and 222Asp → Asn. Except for the Japan biovar bacteria, all strains of the Holarctic subspecies contain two stop codons in the ctu gene. The bacteria of the novicida subspecies contain the ctu gene only in the strain 3523, whereas the other strains contain the FTN_0827 gene encoding the CN hydrolase, which probably provides the citrulline ureidase activity.     

A proposed new bacteriophage subfamily: “<Emphasis Type="Italic">Jerseyvirinae</Emphasis>”

Based on morphology and comparative nucleotide and protein sequence analysis, a new subfamily of the family Siphoviridae is proposed, named “Jerseyvirinae” and consisting of three genera, “Jerseylikevirus”, “Sp3unalikevirus” and “K1glikevirus”. To date, this subfamily consists of 18 phages for which the genomes have been sequenced. Salmonella phages Jersey, vB_SenS_AG11, vB_SenS-Ent1, vB_SenS-Ent2, vB_SenS-Ent3, FSL SP-101, SETP3, SETP7, SETP13, SE2, SS3e and wksl3 form the proposed genus “Jerseylikevirus”. The proposed genus “K1glikevirus” consists of Escherichia phages K1G, K1H, K1ind1, K1ind2 and K1ind3. The proposed genus “Sp3unalikevirus” contains one member so far. Jersey-like phages appear to be widely distributed, as the above phages were isolated in the UK, Canada, the USA and South Korea between 1970 and the present day. The distinguishing features of this subfamily include a distinct siphovirus morphotype, genomes of 40.7-43.6 kb (49.6-51.4 mol % G+C), a syntenic genome organisation, and a high degree of nucleotide sequence identity and shared proteins. All known members of the proposed subfamily are strictly lytic.     

Molecular evidence of <Emphasis Type="Italic">Chlamydiales</Emphasis> in ticks from wild and domestic hosts in Sardinia,Italy

Ticks are well known to be important vectors for a wide range of bacteria, viruses and protozoa affecting human and animal health. Ixodid ticks are widely distributed in Sardinia, and an increasing number of tick-borne bacteria have been documented in the island. A growing number of evidence are supporting the hypothesis of alternative transmission routes for chlamydial bacteria such as the involvement of vectors. This study was conducted to provide possible molecular detection of members belonging to the Chlamydiales order in Sardinian ticks and to update information concerning the presence of new ectoparasite-borne bacteria in ticks collected from domestic and wild hosts in a typical Mediterranean environment. A total of 378 ticks were individually screened with a pan-Chlamydiales specific primers targeting the 16S rRNA gene. Chlamydiales DNA was detected in 28% of the total ticks analyzed. The analyses of sequences highlighted that Rhipicephalus sanguineus sensu lato, Rhipicephalus bursa, Rhipicephalus annulatus, Haemaphysalis sulcata, Haemaphysalis punctata and Dermacentor marginatus ticks exhibited DNA of Chlamydiaceae and Parachlamydiaceae members. Our results revealed that DNA of zoonotic microorganisms such as C. psittaci, C. abortus and the emerging pathogen Parachlamydia acanthamoebae are present in Sardinian ticks. Since routes of Chlamydia transmission are yet to be fully defined, the role of ticks as possible vectors for Chlamydiales remains the most challenging and interesting question to be addressed in future research. Continued monitoring of these pathogens in tick vectors is needed to provide strategies for controlling of possible chlamydial infections and disease outbreaks in the island.     

Initial Host Response to Bacteria in the Murine Lung Differs Between <Emphasis Type="BoldItalic">Pseudomonas aeruginosa</Emphasis>, <Emphasis Type="BoldItalic">Staphylococcus aureus</Emphasis> and <Emphasis Type="BoldItalic">Streptococcus pneumoniae</Emphasis>

Phagocytosis of bacteria is an important process during early host defence. It has been directly observed only ex vivo or in vitro. Here, we report on the observation of phagocytosis under in vivo conditions by using intravital microscopy in the murine lung. Suspensions of fluorescently labelled Streptococcus pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa cells were each instilled intratracheally to anaesthetized mice. After thoracotomy, the alveolar surface was observed for 30 min. Alveolar phagocytes exhibiting ingested bacteria could be detected and counted. The highest numbers were found after the infection with P. aeruginosa. By using intravital microscopy, cellular host defence could be observed in living mice lungs. The initial phagocytic reaction crucially depends on the species of applied bacteria invading the lung.     

Novel diagnostic ELISA test for discrimination between infections with <Emphasis Type="Italic">Yersinia enterocolitica</Emphasis> and <Emphasis Type="Italic">Yersinia pseudotuberculosis</Emphasis>

Yersiniosis is a foodborne infection caused by Yersinia enterocolitica or Yersinia pseudotuberculosis. Although yersiniosis is most often self-limiting, some patients develop chronic infections, such as reactive arthritis, glomerulonephritis, or myocarditis, which require an antibiotic treatment. Whereas early infections can be diagnosed by direct detection of bacteria, chronic infections can only be identified by serological tests. At this point, a serological method for differentiation between infections with the two Yersinia species is important since antibiotic susceptibility of these bacteria is different. Traditional immunoassays do not distinguish between infections with Y. enterocolitica and Y. pseudotuberculosis. The only test that allows for this differentiation is Mikrogen’s strip test where discrimination between the two types of infection is based on two recombinant bacterial proteins, MyfA and PsaA (specific for Y. enterocolitica and Y. pseudotuberculosis, respectively). Here, we show that Y. enterocolitica and Y. pseudotuberculosis, cultured under the conditions that mimic the natural rout of infection, express surface antigens different from MyfA and PsaA that can also be used in a discrimination test. Further, we describe a new ELISA that is based on the whole bacteria and recombinant MyfA and PsaA as antigens, and that allows the differentiation between infections with Y. enterocolitica and Y. pseudotuberculosis and simultaneous detection of yersiniosis.     

Associations between common intestinal parasites and bacteria in humans as revealed by qPCR

Several studies have shown associations between groups of intestinal bacterial or specific ratios between bacterial groups and various disease traits. Meanwhile, little is known about interactions and associations between eukaryotic and prokaryotic microorganisms in the human gut. In this work, we set out to investigate potential associations between common single-celled parasites such as Blastocystis spp. and Dientamoeba fragilis and intestinal bacteria. Stool DNA from patients with intestinal symptoms were selected based on being Blastocystis spp.-positive (B+)/negative (B?) and D. fragilis-positive (D+)/negative (D?), and split into four groups of 21 samples (B+ D+, B+ D?, B? D+, and B? D?). Quantitative PCR targeting the six bacterial taxa Bacteroides, Prevotella, the butyrate-producing clostridial clusters IV and XIVa, the mucin-degrading Akkermansia muciniphila, and the indigenous group of Bifidobacterium was subsequently performed, and the relative abundance of these bacteria across the four groups was compared. The relative abundance of Bacteroides in B– D– samples was significantly higher compared with B+ D? and B+ D+ samples (P?<?0.05 and P?<?0.01, respectively), and this association was even more significant when comparing all parasite-positive samples with parasite-negative samples (P?<?0.001). Additionally, our data revealed that a low abundance of Prevotella and a higher abundance of Clostridial cluster XIVa was associated with parasite-negative samples (P?<?0.05 and P?<?0.01, respectively). Our data support the theory that Blastocystis alone or combined with D. fragilis is associated with gut microbiota characterized by low relative abundances of Bacteroides and Clostridial cluster XIVa and high levels of Prevotella.     

Isolation and characterization of a novel,T7-like phage against <Emphasis Type="Italic">Aeromonas veronii</Emphasis>

A virulent Aeromonas veronii biovar sobria and the corresponding novel, lytic bacteriophage (VTCCBPA5) were isolated from village pond water. The phage was found to belong to family Podoviridae. PCR analysis of major capsid protein gene confirmed its classification to T7-like genus. The protein profiling by SDS-PAGE indicated the major structural protein to be ~ 45 kDa. The phage (VTCCBPA5) is host specific and is stable over a range of pH (6–10) and temperatures (4–45 °C). On the basis of restriction endonuclease analysis combined with prediction mapping, it was observed to vary significantly from previously reported podophages of Aeromonas sp., viz. phiAS7 and Ahp1. The phylogenetic analysis on the basis of PCR-amplified segment of DNA polymerase gene of phage revealed it being an outgroup from podophages of Klebsiella sp. and Pseudomonas sp. though a small internal fragment (359 bp) showed the highest identity (77%) with Vibrio sp. phages. Thus, this is the first report of a novel Podoviridae phage against A. veronii. It expands the assemblage of podophages against Aeromonas sp. and BPA5 could be potentially useful in biocontrol of environmentally acquired Aeromonas veronii infections.     

Hematological and biochemical reference intervals for <Emphasis Type="Italic">Bothrops asper</Emphasis> and <Emphasis Type="Italic">Crotalus simus</Emphasis> (Serpentes: Viperidae), maintained in captivity for venom extraction

This study presents hematological and biochemical reference intervals (RIs) for two species of viper snakes (Bothrops asper and Crotalus simus), which are the first of their type particularly for these two species maintained in captivity and for extraction of venom purposes. A total of 77 snakes were used in developing the study; specifically 39 B. asper and 38 C. simus snakes. Blood samples were obtained by puncturing the caudal vein, and hematological tests were performed manually by two independent technicians. Plasma biochemistry parameters were determined by an automatized analyzer. There are hematological differences between wild-caught and captive B. asper in the percentage of heterophils (P?<?0.001), while in captive and wild-caught C. simus, the differences are found in the percentage of eosinophils, lymphocytes, and monocytes (P?<?0.001). Differences in glucose (P?=?0.012), uric acid (P?<?0.001), and cholinesterase (P?=?0.004) are found in captive and wild-caught B. asper. Differences in albumin (P?=?0.002), calcium (P?<?0.001), CK (P?=?0.04), and LDH (P?=?0.037) are found between captive and wild-caught C. simus. This study constitutes the first set of hematological and biochemical RIs for B. asper and C. simus maintained in captivity with the purpose of producing antivenom in Costa Rica. The establishment of comprehensive RIs for hematology and plasma biochemistry for these two species of snakes is useful for interpretation of blood test results, moreover, to serving as a reference for viper snakes used for research purposes.     

Immunogenicity of recombinant <Emphasis Type="Italic">Bacillus</Emphasis> strains with a cloned gene for synthesis of the protective antigen of <Emphasis Type="Italic">Bacillus anthracis</Emphasis>

A hybrid plasmid pUB110PA-1, which functions stably in cells of Bacillus strains and contains the gene for synthesis of the protective antigen of the anthrax microbe, Bacillus anthracis, has been constructed. Recombinant strains were obtained that surpass anthrax Bacillus cultures in the secretory synthesis of the protective antigen. Their immunologic effectiveness was assessed. A single immunization of guinea pigs with the recombinant strains in a dose of 5 × 10⁷ spores provides effective protection from infection by the anthrax pathogen. The immune response is characterized by high values of the immunity indices and titers of antibodies against the protective antigen. The recombinant strains do not possess residual virulence for guinea pigs and BALB/mice, in contrast to anthrax vaccine preparations.     

Antimicrobial effects of new designed 2-amino-tetrahydro-4<Emphasis Type="Italic">H</Emphasis>-chromene-3-carbonitrile derivatives against some pathogenic microbial strains

Chromenes, also called benzopyrane derivatives and chromene-4-one, are natural compounds which have several biological effects. The aims of the present study were to synthesize 2-amino-tetrahydro-4H-chromene-3-carbonitrile derivatives and to evaluate their antibacterial effects against selected bacterial strains. Nine 2-amino-tetrahydro-4H-chromene-3-carbonitrile derivatives were designed and synthesized. Each synthesized derivative was dissolved in dimethyl sulfoxide and diluted using distilled water. Then, serial dilutions of 64, 32, 16, 8, 4, 2, 1, 0.5, 0.25, and 0.125 μg/ml were prepared and added to the Mueller-Hinton agar medium. The minimum inhibitory concentration (MIC) of derivatives was determined against routine pathological strains of bacteria including Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Escherichia coli, Serratia marcescens, Pseudomonas aeruginosa, and Klebsiella pneumoniae on the basis of growth on the each plate. Only two compounds of 2-amino-5,6,6,1-tetrahydro-5-oxo-4-(3-pyridinyl)-4H-chromene-3-carbonitrile and 2-amino-5,6,6,1-tetrahydro-6,6-dimethyl-5-oxo-4-(3-pyridinyl)-4H-chromene-3-carbonitrile showed antibacterial activity especially against M. luteus and B. subtilis. Some of 2-amino-tetrahydro-4H-chromene-3-carbonitrile derivatives had stronger antibacterial effects which may be due to substituted pyridine ring. Therefore, these compounds are a candidate as the new choices of antibacterial drugs.     

Use of Andromas and Bruker MALDI-TOF MS in the identification of <Emphasis Type="Italic">Neisseria</Emphasis>

Through the past decade, MALDI-TOF MS has been recognized as a fast and robust tool for identification of most bacteria in clinical microbiology. However, the accuracy of this method to identify Neisseria species is still debated, and few data are available about commensal Neisseria species identification. In this study, we assessed two MALDI-TOF MS systems (Bruker Biotyper and Andromas) for the identification of 88, 18, and 29 isolates of Neisseria gonorrhoeae, Neisseria meningitidis, and commensal Neisseria species, respectively. All 88 isolates of N. gonorrhoeae were correctly identified using both systems, and most N. meningitidis and commensal Neisseria species were well identified: only 1/18 isolates of N. meningitidis was misidentified using Bruker Biotyper, and 1 isolate of Neisseria polysaccharea was misidentified as N. meningitidis using both systems. These results strengthen the possibility to use MALDI-TOF MS as a single method for Neisseria identification in routine, with excellent performance for N. gonorrhoeae identification. However, results should be interpreted prudently for N. meningitdis and commensal Neisseria species when isolated from genital and oropharyngeal samples where these both species can coexist.     

Reduction in fecal microbiota diversity and short-chain fatty acid producers in Methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> infected individuals as revealed by PacBio single molecule,real-time sequencing technology

Methicillin-resistant Staphylococcus aureus (MRSA) may cause potentially lethal infections. Increasing evidence suggests that the gut microbiota is associated with human health. Yet, whether patients with MRSA infections carry specific signatures in their fecal microbiota composition has not been determined. Thus, this study aimed to compare the fecal microbiota profile of MRSA-positive patients (n=15) with individuals without MRSA infection (n=15) by using the PacBio single molecule, real-time (SMRT) DNA sequencing system and real-time quantitative polymerase chain reaction (qPCR). Mann-Whitney tests and unweighted UniFrac principal coordinate analysis (PCoA) showed that the profile of fecal microbiota was apparently different between the two populations. Both the community richness and diversity were reduced in the MRSA-positive group (p<0.050). The genera Acinetobacter and Enterococcus were highly enriched in the MRSA-positive group, whereas less short-chain fatty acid (SCFA)-producing bacteria, including Butyricimonas, Faecalibacterium, Roseburia, Ruminococcus, Megamonas and Phascolarctobacterium, were detected in the MRSA-positive group. At species level, the species Acinetobacter baumannii and Bacteroides thetaiotaomicron were prevalent in the MRSA-positive group, whereas opposite trends were observed in 17 other species, such as Faecalibacterium prausnitzii, Lactobacillus rogosae, Megamonas rupellensis and Phascolarctobacterium faecium. Positive correlations were observed between Acinetobacter baumannii and erythrocyte sedimentation rate (ESR) (R=0.554, p=0.001), as well as hypersensitive C reactive protein (hsCRP) (R=0.406, p=0.026). Faecalibacterium prausnitzii was negatively associated with ESR (R=-0.545, p=0.002), hsCRP (R=-0.401, p=0.028) and total bile acids (TBA) (R=-0.364, p=0.048). In conclusion, the fecal microbiota structure was different between MRSA-positive and -negative patients. The increase in potential pathogens with the reduction of beneficial populations, such as SCFA-producing bacteria, in MRSA-positive patients may affect prognosis.     

Erratum to: Seasonal trend and clinical presentation of <Emphasis Type="Italic">Bacillus cereus</Emphasis> bloodstream infection: association with summer and indwelling catheter

Bacillus cereus, an opportunistic pathogen, can cause fatal infection. However, B. cereus bloodstream infections (BSIs) have not been well characterised. From 2008 to 2013, B. cereus isolates from all of the specimens and patients with B. cereus BSIs were identified. Environmental samples were collected to detect B. cereus contamination. We also characterised the clinical presentation of B. cereus BSI through analyses of risk factors for BSI and mortality. A total of 143 clinical B. cereus isolates was detected. Fifty-one patients with nosocomial infections were diagnosed as B. cereus BSI, and 37 had contaminated blood cultures. The number of B. cereus isolates and BSI patients was significantly greater from June to September than from January to April (3.4 vs. 1.0 per month and 1.4 vs. 0.2, respectively). All BSIs were nosocomial and related to central or peripheral vascular catheter. Urinary catheter [odds ratio (OR) 6.93, 95 % confidence interval (CI) 2.40–20.0] was the independent risk factor associated with BSI patients when compared to patients regarded as contaminated. In-hospital mortality among BSI patients was 20 % and was associated with urinary catheter (OR 12.3, 95 % CI 0.67–225, p=0.045) and higher Charlson index (OR 1.99, 95 % CI 1.26–3.12). The number of B. cereus isolates and BSI increased during summer. Inpatients with indwelling vascular or urinary catheters should be carefully monitored for potential B. cereus BSIs.     

Association of diverse bacterial communities in human bile samples with biliary tract disorders: a survey using culture and polymerase chain reaction-denaturing gradient gel electrophoresis methods

Bacterial infection is considered a predisposing factor for disorders of the biliary tract. This study aimed to determine the diversity of bacterial communities in bile samples and their involvement in the occurrence of biliary tract diseases. A total of 102 bile samples were collected during endoscopic retrograde cholangiopancreatography (ERCP). Characterization of bacteria was done using culture and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) methods. Antimicrobial susceptibility of the isolates was determined based on the Clinical and Laboratory Standards Institute (CLSI) guidelines and identity of the nucleotide sequences of differentiated bands from the DGGE gels was determined based on GenBank data. In total, 41.2 % (42/102) of the patients showed bacterial infection in their bile samples. This infection was detected in 21 % (4/19), 45.4 % (5/11), 53.5 % (15/28), and 54.5 % (24/44) of patients with common bile duct stone, microlithiasis, malignancy, and gallbladder stone, respectively. Escherichia coli showed a significant association with gallstones. Polymicrobial infection was detected in 48 % of the patients. While results of the culture method established coexistence of biofilm-forming bacteria (Pseudomonas aeruginosa, E. coli, Klebsiella pneumoniae, Enterococcus spp., and Acinetobacter spp.) in different combinations, the presence of Capnocytophaga spp., Lactococcus spp., Bacillus spp., Staphylococcus haemolyticus, Enterobacter or Citrobacter spp., Morganella spp., Salmonella spp., and Helicobacter pylori was also characterized in these samples by the PCR-DGGE method. Multidrug resistance phenotypes (87.5 %) and resistance to third- and fourth-generation cephalosporins and quinolones were common in these strains, which could evolve through their selection by bile components. Ability for biofilm formation seems to be a need for polymicrobial infection in this organ.