LSD1 Regulates Neurogenesis in Human Neural Stem Cells Through the Repression of Human-Enriched Extracellular Matrix and Cell Adhesion Genes.

Neurogenesis begins with neural stem cells undergoing symmetric proliferative divisions to expand and then switching to asymmetric differentiative divisions to generate neurons in the developing brain. Chromatin regulation plays a critical role in this switch. Histone lysine-specific demethylase LSD1 demethylates H3K4me1/2 and H3K9me1/2 but the mechanisms of its global regulatory functions in human neuronal development remain unclear. We performed genome-wide ChIP-seq of LSD1 occupancy, RNA-seq, and Histone ChIP-seq upon LSD1 inhibition to identify its repressive role in human neural stem cells. Novel downstream effectors of LSD1 were identified, including the Notch signaling pathway genes and human-neural progenitor-enriched extracellular matrix (ECM) pathway/cell adhesion genes, which were upregulated upon LSD1 inhibition. LSD1 inhibition led to decreased neurogenesis, and overexpression of downstream effectors mimicked this effect. Histone ChIP-seq analysis revealed that active and enhancer markers H3K4me2, H3K4me1, and H3K9me1 were upregulated upon LSD1 inhibition, while the repressive H3K9me2 mark remained mostly unchanged. Our work identifies the human-neural progenitor-enriched ECM pathway/cell adhesion genes and Notch signaling pathway genes as novel downstream effectors of LSD1, regulating neuronal differentiation in human neural stem cells.

Biofilm-producing ability of methicillin-resistant Staphylococcus aureus clinically isolated in China.

BACKGROUND: Staphylococcus aureus, a commensal bacterium, colonizes the skin and mucous membranes of approximately 30% of the human population. Apart from conventional resistance mechanisms, one of the pathogenic features of S. aureus is its ability to survive in a biofilm state on both biotic and abiotic surfaces. Due to this characteristic, S. aureus is a major cause of human infections, with Methicillin-Resistant Staphylococcus aureus (MRSA) being a significant contributor to both community-acquired and hospital-acquired infections. RESULTS: Analyzing non-repetitive clinical isolates of MRSA collected from seven provinces and cities in China between 2014 and 2020, it was observed that 53.2% of the MRSA isolates exhibited varying degrees of ability to produce biofilm. The biofilm positivity rate was notably high in MRSA isolates from Guangdong, Jiangxi, and Hubei. The predominant MRSA strains collected in this study were of sequence types ST59, ST5, and ST239, with the biofilm-producing capability mainly distributed among moderate and weak biofilm producers within these ST types. Notably, certain sequence types, such as ST88, exhibited a high prevalence of strong biofilm-producing strains. The study found that SCCmec IV was the predominant type among biofilm-positive MRSA, followed by SCCmec II. Comparing strains with weak and strong biofilm production capabilities, the positive rates of the sdrD and sdrE were higher in strong biofilm producers. The genetic determinants ebp, icaA, icaB, icaC, icaD, icaR, and sdrE were associated with strong biofilm production in MRSA. Additionally, biofilm-negative MRSA isolates showed higher sensitivity rates to cefalotin (94.8%), daptomycin (94.5%), mupirocin (86.5%), teicoplanin (94.5%), fusidic acid (81.0%), and dalbavancin (94.5%) compared to biofilm-positive MRSA isolates. The biofilm positivity rate was consistently above 50% in all collected specimen types. CONCLUSIONS: MRSA strains with biofilm production capability warrant increased vigilance.

Adhesion mechanism and biofilm formation of Escherichia coli O157:H7 in infected cucumber (Cucumis sativus L.).

Cucumber is usually eaten as a raw vegetable and easily contaminated by pathogenic microorganisms; the contamination process includes colonization, proliferation, and biofilm formation. In this study, plate counting was used to determine the stage of E. coli O157:H7 colonization/proliferation in cucumber epidermis and fruit. Expression of E. coli genes associated with adhesion, movement and oxidative stress response during colonization and proliferation in cucumber was evaluated with fluorescence real-time quantitative PCR. Scanning electron microscopy imaging was used to observe biofilm formation over time in different cucumber tissues at 4 °C and 25 °C. During colonization (at 0-45 and 0-30 min in epidermis and fruit, respectively), escV, fliC, espA, escN, espF, espG, espZ, nleA, tir, and ycbR genes were upregulated. The escC was downregulated, while map and espH expression did not vary. During proliferation (after 45 and 30 min in epidermis and fruit, respectively), fliC was downregulated, whereas the outer membrane protein intimin gene and oxidative stress genes rpoS and sodB were upregulated. During storage, 25 °C was more favorable for biofilm formation than 4 °C. The ability of biofilm formation on the vascular system was the strongest, and the biofilm on epidermis sloughed off earlier than that on other tissues. Clarifying the process of E. coli O157:H7 contaminating cucumbers provided useful information for the development of prevention and control methods of fresh-cut cucumber.

Virulence genes of Escherichia coli in diarrheic and healthy calves.

Escherichia coli ETEC, EPEC, NTEC and STEC/EHEC pathotypes are often isolated from bovine feces. The objective of this study was to detect 21 E. coli virulence genes in feces from 252 dairy calves in Uruguay (149 with neonatal diarrhea - NCD - and 103 asymptomatic). Genes iucD, f17A, afa8E, papC, clpG and f17G(II) were the most prevalent (81.3%; 48.4%; 37.3%; 35.7%; 34.1%; 31.3%, respectively). Genes eae, stx1and stx2 were poorly represented; 13/252 animals harbored one or a combination of these genes. The prevalence of the cnf gene was 4.4%, while that of cdt-IV and cdt-III genes was 24.2% and 12.7% respectively. This study reports updated data about the virulence profiles of E. coli in dairy calves in Uruguay. A large number of adhesins and toxin genes were detected. Our results demonstrate that E. coli from bovine feces has diarrheagenic and extraintestinal profiles although other NCD risks factors may contribute to the disease outcome.

Novel Avian Pathogenic Escherichia coli Genes Responsible for Adhesion to Chicken and Human Cell Lines.

Avian pathogenic Escherichia coli (APEC) is a major bacterial pathogen of commercial poultry contributing to extensive economic losses and contamination of the food chain. One of the initial steps in bacterial infection and successful colonization of the host is adhesion to the host cells. A random transposon mutant library (n = 1,300) of APEC IMT 5155 was screened phenotypically for adhesion to chicken (CHIC-8E11) and human (LoVo) intestinal epithelial cell lines. The detection and quantification of adherent bacteria were performed by a modified APEC-specific antibody staining assay using fluorescence microscopy coupled to automated VideoScan technology. Eleven mutants were found to have significantly altered adhesion to the cell lines examined. Mutated genes in these 11 "adhesion-altered mutants" were identified by arbitrary PCR and DNA sequencing. The genes were amplified from wild-type APEC IMT 5155, cloned, and transformed into the respective adhesion-altered mutants, and complementation was determined in adhesion assays. Here, we report contributions of the fdtA, rluD, yjhB, ecpR, and fdeC genes of APEC in adhesion to chicken and human intestinal cell lines. Identification of the roles of these genes in APEC pathogenesis will contribute to prevention and control of APEC infections.IMPORTANCE Avian pathogenic E. coli is not only pathogenic for commercial poultry but can also cause foodborne infections in humans utilizing the same attachment and virulence mechanisms. Our aim was to identify genes of avian pathogenic E. coli involved in adhesion to chicken and human cells in order to understand the colonization and pathogenesis of these bacteria. In contrast to the recent studies based on genotypic and bioinformatics data, we have used a combination of phenotypic and genotypic approaches for identification of novel genes contributing to adhesion in chicken and human cell lines. Identification of adhesion factors remains important, as antibodies elicited against such factors have shown potential to block colonization and ultimately prevent disease as prophylactic vaccines. Therefore, the data will augment the understanding of disease pathogenesis and ultimately in designing strategies against the infections.

Diversity of probiotic adhesion genes in the gastrointestinal tract of goats.

Gastrointestinal (GI) microflora is an important system in the host, as it has both pathogenic and probiotic bacteria. Most of the studies were focused on the human gut microflora and the available information on the intestinal microflora of goats was limited. This urged the need to inspect the impacts of the goat's gut microflora. Metagenomic investigation of probiotic bacteria in the GI tract of goat is one of the challenging streams because of the less available data of the uncultivable bacteria. In our report, comparative analysis of metagenomic and enrichment samples of goat intestinal content was done and this approach will be helpful in analyzing the identification of uncultivable and cultivable probiotic bacteria. This study mainly focused on three key probiotic adhesion genes, such as EF-Tu, mapA, and mub. The GI of four different goats were investigated for these genes. The data from this study showed that there is a wide diversity of these genes among goat intestinal samples.

Altered expression of cell adhesion genes and hybrid male sterility between subspecies of Drosophila pseudoobscura.

Drosophila pseudoobscura pseudoobscura and Drosophila pseudoobscura bogotana are two closely related subspecies with incomplete reproductive isolation. A genome-wide comparison of expression in hybrids relative to parental subspecies has been previously used to identify genes with significant changes in expression uniquely associated with the sterile condition. The misexpression (i.e., gene expression beyond levels found in parentals) of such genes could be directly linked to the onset of sterility or could alternatively be caused by incompatibilities in a hybrid genome without a direct link to sterility. Cell adhesion was previously found to be one of the largest gene ontologies with changes in expression linked to sterility. Here we used gene expression assays in fertile backcross male progeny, along with introgression progeny in which we swap a major hybrid male sterility (HMS) allele, to generate fertile and sterile males genotypically similar to F1 sterile hybrids. We identify a cell adhesion gene (GA10921) whose change in expression is directly linked to sterility and modulated by a previously characterized HMS protein. GA10921 adds to our rather limited knowledge of changes in gene expression associated with HMS, and to the identification of gene interacting partners linked to HMS.

Molecular Typing and Virulence Gene Profiles of Enterotoxin Gene Cluster (egc)-Positive Staphylococcus aureus Isolates Obtained from Various Food and Clinical Specimens.

The enterotoxin gene cluster (egc) has been proposed to contribute to the Staphylococcus aureus colonization, which highlights the need to evaluate genetic diversity and virulence gene profiles of the egc-positive population. Here, a total of 43 egc-positive isolates (16.2%) were identified from 266 S. aureus isolates that were obtained from various food and clinical specimens in Shanghai. Seven different egc profiles were found based on the polymerase chain reaction (PCR) result for egc genes. Then, these 43 egc-positive isolates were further typed by multilocus sequence typing, pulsed-field gel electrophoresis (PFGE), multiple-locus variable-number tandem-repeat analysis (MLVA), and accessory gene regulatory (agr) typing. It showed that the 43 egc-positive isolates displayed 17 sequence types, 28 PFGE patterns, 29 MLVA types, and 4 agr types, respectively. Among them, the dominant clonal lineage was CC5-agr II (48.84%). Thirty toxin and 20 adhesion-associated genes were detected by PCR in egc-positive isolates. Notably, invasive toxin genes showed a high prevalence, such as 76.7% for Panton-Valentine leukocidin encoding genes, 27.9% for sec, and 23.3% for tsst-1. Most of the examined adhesion-associated genes were found to be conserved (76.7-100%), whereas the fnbB gene was only found in 8 (18.6%) isolates. In addition, 33 toxin gene profiles and 13 adhesion gene profiles were identified, respectively. Our results imply that isolates belonging to the same clonal lineage harbored similar adhesion gene profiles but diverse toxin gene profiles. Overall, the high prevalence of invasive virulence genes increases the potential risk of egc-positive isolates in S. aureus infection.

Dentin tubule invasion by Enterococcus faecalis under stress conditions ex vivo.

Enterococcus faecalis is the species most frequently isolated from failed endodontic treatments because it can survive under stress conditions imposed by root canal treatment. The objective of this study was to determine the ability of E. faecalis to invade dentine tubules under alkaline and energy-starvation stress and to explore the potential mechanisms. Roots from single-rooted human teeth were infected with E. faecalis under alkaline and energy-starvation stress conditions. After 4 wk of culture, samples were processed to establish the tubule-penetration distance. In addition, the hydrophobicity of E. faecalis cells under these conditions was analysed and the expression of genes involved in adhesion was quantified by real-time quantitative PCR. Culture of E. faecalis under alkaline and energy-starvation stress conditions resulted in a marked reduction of tubule-penetration distance, a significant increase in hydrophobicity of the bacterial surface, and marked down-regulation of most adhesin genes compared with E. faecalis cultured in tryptic soy broth. The results indicate that the dentine tubule invasion ability of E. faecalis was markedly decreased under alkaline and glucose-starvation stress conditions, possibly because of the increase of hydrophobicity and down-regulation of some adhesion genes.

Addition of lime juice and NaCl to minced seafood may stimulate the expression of Listeria monocytogenes virulence, adhesion, and stress response genes.

Listeria monocytogenes is a ubiquitous opportunistic bacterium responsible for deadly listeriosis outbreaks. This pathogen has been recognized as a significant food-borne pathogen in seafood products. The present study aimed to investigate the transcript levels of virulence, adhesion, and stress response genes of L. monocytogenes upon exposure to sublethal levels of lime juice and NaCl in shrimp matrix. For this purpose, minced and broth shrimp samples (control, 2% NaCl, 5% NaCl, 25 µL/mL lime, and 50 µL/mL lime, as well as 2% NaCl+25 µL/mL lime) were inoculated with approximately 107 CFU/g or ml of L. monocytogenes, and subsequently, the samples were stored at 12°C or 37°C. For the minced samples, the transcription of one stress-related (sigB), two adhesion (imo1634 and imo1847), and four virulence (hly, prf, intA, and plc) genes was assessed by RT-qPCR after different storage times (0 and 48 h). Results showed that the transcript levels of sigB, imo1847, and imo1634 genes increased with increasing storage temperatures of shrimp broth (12°C to 37°C). At the beginning, the transcription of the studied genes decreased in all treatments of minced shrimp; however, after 48 h of storage at 12°C, the transcript levels of hly, prf, imo1847, imo1634, and intA genes were significantly upregulated up to 0.5-9 log2 fold-change in all treatments compared to the control group (p < .05). These results highlight that the survived L. monocytogenes after exposure to moderate salt content or lime juice could represent enhanced virulence and adhesion capabilities, posing a significant public health risk.

Antibiotics Resistance and Adhesive Properties of Clinical Staphylococcus aureus Isolated from Wound Infections.

Staphylococcus aureus (S. aureus) is a ubiquitous pathogen responsible for several severe infections. This study aimed to investigate the adhesive properties and antibiotic resistance among clinical S. aureus isolated from Hail Hospital Province, Kingdom of Saudi Arabia (KSA), using molecular approaches. This study was conducted according to the ethical committee at Hail's guidelines on twenty-four S. aureus isolates. A polymerase chain reaction (PCR) was performed to identify genes encoding the ß-lactamase resistance (blaZ), methicillin resistance (mecA), fluoroquinolone resistance (norA), nitric oxide reductase (norB), fibronectin (fnbA and fnbB), clumping factor (clfA) and intracellular adhesion factors (icaA and icaD). This qualitative study tested adhesion based on exopolysaccharide production on Congo red agar (CRA) medium and biofilm formation on polystyrene by S. aureus strains. Among 24 isolates, the cna and blaz were the most prevalent (70.8%), followed by norB (54.1%), clfA (50.0%), norA (41.6%), mecA and fnbB (37.5%) and fnbA (33.3%). The presence of icaA/icaD genes was demonstrated in almost all tested strains in comparison to the reference strain, S. aureus ATCC 43300. The phenotypic study of adhesion showed that all tested strains had moderate biofilm-forming capacity on polystyrene and represented different morphotypes on a CRA medium. Five strains among the twenty-four harbored the four genes of resistance to antibiotics (mecA, norA, norB and blaz). Considering the genes of adhesion (cna, clfA, fnbA and fnbB), these genes were present in 25% of the tested isolates. Regarding the adhesive properties, the clinical isolates of S. aureus formed biofilm on polystyrene, and only one strain (S17) produced exopolysaccharides on Congo red agar. All these results contribute to an understanding that the pathogenesis of clinical S. aureus isolates is due to their antibiotic resistance and adhesion to medical material.

Molecular Characterization of Community- and Hospital- Acquired Methicillin-Resistant Staphylococcus aureus Isolates during COVID-19 Pandemic.

Methicillin-resistant Staphylococcus aureus (MRSA) is a drug-resistant superbug that causes various types of community- and hospital-acquired infectious diseases. The current study was aimed to see the genetic characteristics and gene expression of MRSA isolates of nosocomial origin. A total of 221 MRSA isolates were identified from 2965 clinical samples. To identify the bacterial isolates, the clinical samples were inoculated on blood agar media plates first and incubated at 37 °C for 18-24 h. For further identification, the Gram staining and various biochemical tests were performed once the colonies appeared on the inoculated agar plates. The phenotypic identification of antibiotic susceptibility patterns was carried out using Kirby-Bauer disk diffusion method by following the Clinical and Laboratory Standards Institute (CLSI) 2019 guidelines. The biofilm-producing potentials of MRSA were checked quantitatively using a spectrophotometric assay. All strains were characterized genotypically by SCCmec and agr typing using the specific gene primers. Furthermore, a total of twelve adhesion genes were amplified in all MRSA isolates. MRSA was a frequently isolated pathogen (44% community acquired (CA)-MRSA and 56% hospital acquired (HA)-MRSA), respectively. Most of the MRSA isolates were weak biofilm producers (78%), followed by moderate (25%) and strong (7%) biofilm producers, respectively. Prominent adhesion genes were clfB (100%), icaAD (91%), fib (91%), sdrC (91%) followed by eno (89%), fnbA (77%), sdrE (67%), icaBC (65%), clfA (65%), fnbB (57%), sdrD (57%), and cna (48%), respectively. The results of the current study will help to understand and manage the spectrum of biofilm-producing MRSA-associated hospital-acquired infections and to provide potential molecular candidates for the identification of biofilm-producing MRSA.

Multi-omics analysis reveals focal adhesion characteristic associated tumor immune microenvironment in colon adenocarcinoma.

Colon adenocarcinoma (COAD) is one of the most frequent malignant lesions of the digestive system in humans, with an insidious onset. At the time of diagnosis, most of them have developed to the middle and late stages, and cancer cells have metastasized, and the prognosis is poor. Treatment options for progressive COAD are limited, and despite the promise of immunotherapy, immunotherapy response rates are low. The assembly and disaggregation of focal adhesion are critical for the directional migration of tumor cells to different sites, and it is unclear whether focal adhesion-related genes are involved in the development and prognosis of colon adenocarcinoma. This study aimed to investigate the role of focal adhesion genes in the occurrence and prognosis of COAD. We obtained datasets of COAD patients, including RNA-sequencing data and clinical information, from the TCGA and GEO databases (GSE17538 and GSE39582). Through CNMF clustering, two molecular subtypes with different expression patterns of focal adhesion genes were identified, and it was found that the molecular subtype with low expression of focal adhesion genes had better prognosis. Then the prediction signature was constructed by LASSO-Cox regression model, and the receiver operating characteristic (ROC) curve showed that the 4-gene signature had a good prediction effect on COAD 1-, 2-, and 3-year OS. Gene function enrichment analysis showed that the high-risk group was mainly enriched in immune and adhesion-related signaling pathways, suggesting that focal adhesion genes may affect the development and prognosis of COAD by regulating the immune microenvironment and tumor metastasis. The interaction between focal adhesion genes and immunity during the occurrence of COAD may help improve the response rate of immunotherapy, which also provides new ideas for the molecular mechanism and targeted therapy in COAD.

Association between Presence of RmpA, MrkA and MrkD Genes and Antibiotic Resistance in Clinical Klebsiella pneumoniae Isolates from Hospitals in Tehran, Iran.

BACKGROUND: Klebsiella pneumoniae is an opportunistic pathogen causing nosocomial infection in human. This study aimed to investigate the relationship between the presence of genes involved in biofilm formation in K. pneumoniae isolated from patients and the presence of antibiotic resistance genes. METHODS: Biochemical tests were used for the identification of K. pneumonia isolated from urine samples referred to hospitals in Tehran, Iran, from Sep 2018 to Jan 2020. The antibiotic resistance pattern was performed and biofilm formation was assessed phenotypically. Finally, ß-lactamase genes and adhesion genes were detected by the PCR method. RESULTS: We collected 457 K. pneumoniae isolates from hospitals in Tehran, Iran. 110 isolates were resistant to imipenem. Fifty isolates were positive for metallo-ß-lactamases that thirty-nine isolates (35.45%) has blaKPC gene, 18 isolates (16.36%) had blaVIM-1 gene and 9 isolates (8.18%) had blaIMP-1 gene detected by PCR. Sixty isolates (54.54%) had strong biofilm, 35 isolates (31.81%) had moderate biofilm and 15 isolates (13.63%) had weak biofilm. The presence of adhesion genes in K. pneumoniae isolates significantly correlated with resistance genes (P<0.001). CONCLUSION: It is clear antibacterial resistance has been significant association with biofilm formation in K. pneumoniae isolates. Therefore, understanding resistance pattern and mechanisms leading to biofilm formation can facilitate efficient treatment of infections caused by K. pneumoniae.

The Role of Subinhibitory Concentrations of Daptomycin and Tigecycline in Modulating Virulence in Staphylococcus aureus.

Staphylococcus aureus (S. aureus) infections are notoriously complicated by the ability of the organism to grow in biofilms and are difficult to eradicate with antimicrobial therapy. The purpose of the current study was to clarify the influence of sub-inhibitory concentrations (sub-MICs) of daptomycin and tigecycline antibiotics on biofilm adhesion factors and exoproteins expressions by S. aureus clinical isolates. Six clinical isolates representing positive biofilm S. aureus clones (3 methicillin-sensitive S. aureus (MSSA) and 3 methicillin-resistant S. aureus (MRSA)) were grown with sub-MICs (0.5 MIC) of two antibiotics (daptomycin and tigecycline) for 12 h of incubation. RNA extracted from culture pellets was used via relative quantitative real-time-PCR (qRT-PCR) to determine expression of specific adhesion (fnbA, fnbB, clfA, clfB, fib, ebps, cna, eno) and biofilm (icaADBC) genes. To examine the effect of sub-MIC of these antibiotics on the expression of extracellular proteins, samples from the culture supernatants of six isolates were collected after 12 h of treatment with or without tigecycline in order to profile protein production via 2D gel sodium dodecyl sulfate-polyacrylamide gel electrophoresis (2D gel-SDS-PAGE). Sub-MIC treatment of all clinical MRSA and MSSA strains with daptomycin or tigecycline dramatically induced or suppressed fnbA, fnbB, clfA, clfB, fib, ebps, cna, eno, and icaADBC gene expression. Furthermore, sub-MIC use of tigecycline significantly reduced the total number of separated protein spots across all the isolates, as well as decreasing production of certain individual proteins. Collectively, this study showed very different responses in terms of both gene expression and protein secretion across the various isolates. In addition, our results suggest that sub-MIC usage of daptomycin and tigecycline could signal virulence induction by S. aureus via the regulation of biofilm adhesion factor genes and exoproteins. If translating findings to the clinical treatment of S. aureus, the therapeutic regimen should be adapted depending on antibiotic, the virulence factor and strain type.

Biofilm formation and prevalence of adhesion genes among Staphylococcus aureus isolates from different food sources.

To assess biofilm formation ability and identify differences in the prevalence of genes involved in biofilm formation among Staphylococcus aureus strains isolated from different food samples, the ability of biofilm formation among 97 S. aureus strains was evaluated using a colorimetric microtiter plate assay. Thirteen genes encoding microbial surface components recognizing adhesive matrix molecules, and the intracellular adhesion genes were detected by PCR using specific primers. Approximately 72% of the isolates produced biofilms. Among these isolates, 54.64% were weak biofilm producers, while 14.43% and 3.09% produced moderate and strong biofilms, respectively. The icaADBC, clfA/B, cidA, and fib genes were detected in all the S. aureus strains, whereas the bap gene was not present in any of the strains. The occurrence of other adhesin genes varied greatly between biofilm-producing and nonbiofilm-producing strains. However, a significant difference was observed between these two groups with respect to the fnbpB, cna, ebps, and sdrC genes. No obvious evidence was found to support the link between PFGE strain typing and the capacity for biofilm formation. Considerable variation in biofilm formation ability was observed among S. aureus strains isolated from food samples. The prevalence of adhesin-encoding genes also varied greatly within strains. This study highlights the importance of biofilm formation and the adhesins of S. aureus strains in food samples.

Phenotypic and Molecular Detection of Biofilm Formation in Staphylococcus aureus Isolated from Different Sources in Algeria.

Staphylococcus aureus is an opportunistic bacterium causing a wide variety of diseases. Biofilm formation of Staphylococcus aureus is of primary public and animal health concern. The purposes of the present study were to investigate the ability of Staphylococcus aureus isolated from animals, humans, and food samples to form biofilms and to screen for the presence of biofilm-associated and regulatory genes. In total, 55 Staphylococcus aureus isolated from sheep mastitis cases (n = 28), humans (n = 19), and from food matrices (n = 8) were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The ability of Staphylococcus aureus for slime production and biofilm formation was determined quantitatively. A DNA microarray examination was performed to detect adhesion genes (icaACD and biofilm-associated protein gene (bap)), genes encoding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs), regulatory genes (accessory gene regulator (agr) and staphylococcal accessory regulator (sarA)), and the staphylococcal cassette chromosome mec elements (SCCmec). Out of 55 Staphylococcus aureus isolates, 39 (71.0%) and 23 (41.8%) were producing slime and biofilm, respectively. All Staphylococcus aureus strains isolated from food showed biofilm formation ability. 52.6% of the Staphylococcus aureus strains isolated from sheep with mastitis, and 17.9% of isolates from humans, were able to form a biofilm. Microarray analysis typed the Staphylococcus aureus into 15 clonal complexes. Among all Staphylococcus aureus isolates, four of the human isolates (21.1%) harbored the mecA gene (SCCmec type IV) typed into 2 clonal complexes (CC22-MRSA-IV and CC80-MRSA-IV) and were considered as methicillin-resistant, while two of them were slime-producing. None of the isolates from sheep with mastitis harbored the cna gene which is associated with biofilm production. The fnbB gene was found in 100%, 60% and 40% of biofilm-producing Staphylococcus aureus isolated from food, humans, and sheep with mastitis, respectively. Three agr groups were present and agr group III was predominant with 43.6%, followed by agr group I (38.2%), and agr group II (18.2%). This study revealed the capacity of Staphylococcus aureus isolates to form biofilms and highlighted the genetic background displayed by Staphylococcus aureus isolates from different sources in Algeria.

Diverse Profiles of Biofilm and Adhesion Genes in Staphylococcus Aureus Food Strains Isolated from Sushi and Sashimi.

Staphylococcus aureus is able to form multilayer biofilms embedded within a glycocalyx or slime layer. Biofilm formation poses food contamination risks and can subsequently increase the risk of food poisoning. Identification of food-related S. aureus strains will provide additional data on staphylococcal food poisoning involved in biofilm formation. A total of 52 S. aureus strains isolated from sushi and sashimi was investigated to study their ability for biofilm formation using crystal violet staining. The presence of accessory gene regulator (agr) groups and 15 adhesion genes was screened and their associations in biofilm formation were studied. All 52 S. aureus strains showed biofilm production on the tested hydrophobic surface with 44% (23/52) strains classified as strong, 33% (17/52) as moderate, and 23% (12/52) as weak biofilm producers. The frequency of agr-positive strains was 71% (agr group 1 = 21 strains; agr group 2 = 2 strains; agr group 3 = 12 strains; agr group 4 = 2 strains) whereas agr-negative strains were 29% (15/52). Twelve adhesion genes were detected and 98% of the S. aureus strains carried at least one adhesion gene. The ebps was significantly (p < .05) associated with strong biofilm producing strains. In addition, eno, clfA, icaAD, sasG, fnbB, cna, and sasC were significantly higher in the agr-positive group compared to the agr-negative group. The results of this study suggest that the presence of ebps, eno, clfA, icaAD, sasG, fnbB, cna, and sasC may play an important role in enhancing the stage of biofilm-related infections and warrants further investigation. PRACTICAL APPLICATION: This work contributes to the knowledge on the biofilm formation and the distribution of agr groups in S. aureus strains as well as microbial surface components in recognizing adherence matrix molecules of organisms isolated from ready-to-eat sushi and sashimi. The findings provide valuable information to further study the roles of specific genes in causing biofilm-related infections.

Proteomic and genetics insights on the response of the bacteriocinogenic Lactobacillus sakei CRL1862 during biofilm formation on stainless steel surface at 10°C.

Some lactic acid bacteria have the ability to form biofilms on food-industry surfaces and this property could be used to control food pathogens colonization. Lactobacillus sakei CR1862 was selected considering its bacteriocinogenic nature and ability to adhere to abiotic surfaces at low temperatures. In this study, the proteome of L. sakei CRL1862 grown either under biofilm on stainless steel surface and planktonic modes of growth at 10°C, was investigated. Using two-dimensional gel electrophoresis, 29 out of 43 statistically significant spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Ten proteins resulted up-regulated whereas 16 were down-regulated during biofilm formation. Differentially expressed proteins were found to belong to carbohydrate, nucleotide, aminoacid and lipid metabolisms as well as translation, peptide hydrolysis, cell envelope/cell wall biosynthesis, adaption to atypical conditions and protein secretion. Some proteins related to carbohydrate and nucleotide metabolisms, translation and peptide degradation were overexpressed whereas those associated to stress conditions were synthesized in lower amounts. It seems that conditions for biofilm development would not imply a stressful environment for L. sakei CRL1862 cells, directing its growth strategy towards glycolytic flux regulation and reinforcing protein synthesis. In addition, L. sakei CRL1862 showed to harbor nine out of ten assayed genes involved in biofilm formation and protein anchoring. By applying qRT-PCR analysis, four of these genes showed to be up regulated, srtA2 being the most remarkable. The results of this study contribute to the knowledge of the physiology of L. sakei CRL1862 growing in biofilm on a characteristic food contact surface. The use of this strain as green biocide preventing L. monocytogenes post-processing contamination on industrial surfaces may be considered.

What exists beyond cagA and vacA? Helicobacter pylori genes in gastric diseases.

Helicobacter pylori (H. pylori) infection is present in more than half the world's population and has been associated with several gastric disorders, such as gastritis, peptic ulceration, and gastric adenocarcinoma. The clinical outcome of this infection depends on host and bacterial factors where H. pylori virulence genes seem to play a relevant role. Studies of cagA and vacA genes established that they were determining factors in gastric pathogenesis. However, there are gastric cancer cases that are cagA-negative. Several other virulence genes have been searched for, but these genes remain less well known that cagA and vacA. Thus, this review aimed to establish which genes have been suggested as potentially relevant virulence factors for H. pylori-associated gastrointestinal diseases. We focused on the cag-pathogenicity island, genes with adherence and motility functions, and iceA based on the relevance shown in several studies in the literature.