One-pot rapid visual detection of E. coli O157:H7 by label-free AuNP-based plasmonic-aptasensor in water sample.

Access to clean water for irrigation and drinking has long been a global concern. The need for fast, precise, and cost-effective methods to detect harmful bacteria like Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is high due to the potential for severe infectious diseases. Fortunately, recent research has led to developing and utilizing rapid bacterial detection methods. The creation of an aptamer-based biosensor (aptasensor) for the detection of E. coli O157:H7 using label-free aptamers and gold nanoparticles (AuNPs) is described in this study. The specific aptamers that can detect target bacteria are adsorbed on the surface of unmodified AuNPs to form the aptasensor. The detection is performed by target bacterium-induced aptasensor aggregation, which is associated with a red-to-purple color change under high-salt circumstances. We devised a quick and easy method for detecting bacteria using an anti-E. coli O157:H7 aptamer without the need for specialized equipment or pretreatment processes like cell lysis. The aptasensor could identify target bacteria with only as few as 250 colony-forming units (CFU)/ml in 15 min or less, and its specificity based on our test was 100%. This method not only provides a fast direct preparation process but also exhibits remarkable proficiency in promptly identifying the intended target with a heightened level of sensitivity and specificity. Therefore, it can serve as an intelligent tool for monitoring water reservoirs and preventing the transmission of infectious diseases associated with EHEC.

Influence of menthol on biofilm formation, ergosterol content, and cell surface hydrophobicity of Candida glabrata.

Resistance to synthetic antifungals has become one of the leading public health challenges around the world. Accordingly, novel antifungal products like naturally occurring molecules can be one of the potential ways to reach efficient curative approaches to control candidiasis. This work evaluated the effect of menthol on cell surface hydrophobicity (CSH), biofilm formation, growth, and ergosterol content of Candida glabrata, a yeast with a high resistance against antifungal agents. Disc diffusion method (susceptibility to synthetic antifungals), broth micro-dilution method (Susceptibility to menthol), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction assay (biofilm formation), High-performance liquid chromatography (HPLC) technique (ergosterol content), and adherence to n-hexadecane (CSH) were employed to determine the influence of menthol against C. glabrata isolates. The minimum inhibitory concentration (MIC) range of menthol versus C. glabrata was 1250-5000 µg/mL (mean ± SD: 3375 ± 1375 µg/mL). The mean rate of C. glabrata biofilm formation was decreased up to 97.67%, 81.15%, 71.21%, 63.72%, 47.53%, 26.31%, and 0.051% at 625, 1250, 2500, 5000, 10 000, 20 000, and 40 000 µg/mL concentrations, respectively. The percentages of CSH were significant in groups treated with MIC/2 (17.51 ± 5.52%) and MIC/4 (26 ± 5.87%) concentrations of menthol. Also, the percentage changes in membrane ergosterol were 15.97%, 45.34%, and 73.40% at 0.125, 0.25, and 0.5 mg/mL concentrations of menthol, respectively, in comparison with untreated control. The results showed the menthol impact versus sessile and planktonic C. glabrata cells, and the interference with ergosterol content, CSH, and biofilm formation, which made it a potent natural antifungal.

Antimicrobial susceptibility, virulence genes and genomic characterization of Trueperella pyogenes isolated from abscesses in dairy cattle.

Trueperella pyogenes is an opportunistic animal pathogen mainly associated with various suppurative infections in wild and domestic animals. Limited studies have investigated the pathogenesis of diseases caused by this pathogen. The main objective of the current study was to investigate the prevalence, phenotypic properties, virulence genotypes, antimicrobial susceptibility and genetic characterization of T. pyogenes isolated from abscess lesions in different tissues of on-farm dairy cattle. The study was performed on 150 postpartum cattle with clinical abscess symptoms on 22 farms around Tehran, Iran. Classical and disk diffusion methods are used for phenotypic characterization and antibiotic susceptibility. Detection of virulence factor encoding genes and genomic characterization of the isolates also are carried out by conventional PCR and BOX-PCR assays, respectively. Sixty-eight T. pyogenes strains (45.3%) were isolated, 12 were identified as pure cultures and the other 56 strains were isolated from mixed cultures. Seven distinct biotypes were identified among the T. pyogenes isolates. The isolates were mostly resistance to trimethoprim-sulfamethoxazole (70.6%), erythromycin (36.7%), tetracycline (26.5%) and tylosin (23.5%) antibiotics. Also, the genes plo, nanH, nanP and fimA were detected in all isolates. Forty-two isolates (61.7%) carried all virulence factor genes detected in this study. Three isolates only carried plo, nanH, nanP and fimA genes were identified as the least frequent genotype. All sixty-eight isolates and the reference strain were categorized into seven main clusters (A-G). A strong association was observed between virulence factor encoding genes, pathogenicity and biochemical biotypes in some specific clonal relationships.

Morganella Morganii Infection in Hirudo Medicinalis (Iran): A Case Report.

Medicinal leeches (Hirudo medicinalis) are used in surgical and non-surgical manners. Morganella morganii is an opportunistic and zoonotic pathogenic bacterium causing serious clinical complications. In this study, we isolated, discovered and characterized M. morganii-infected H. medicinalis. We detected and identified M. morganii in all inflamed and swollen Hirudo medicinalis samples. The 16S rRNA sequence of the isolates confirmed all strains of M. morganii. All strains were sensitive to Ceftriaxone, Ceftiofur, Danofloxacin, Ciprofloxacin, Enrofloxacin, Oxytetracycline, and Meropenem and were resistant to Erythromycin, Amoxicillin, Ampicillin, Cefazolin, Colistin, Penicillin G, and Lincomycin. This pathogenic bacterium is a zoonotic pathogen, and monitoring the prevalence rate of this bacteria is strongly necessary for leeches used in human medical treatment and care. Finally, all infected leeches were treated successfully in this case report study.

Expression of virulence factor genes in co-infections with Trueperella pyogenes isolates and other bacterial pathogens; an in vivo study.

Trueperella pyogenes is an opportunistic bacterial pathogen causing several infectious diseases, including metritis, mastitis and abscesses in domestic animals such as dairy cattle. Several virulence proteins are released by T. pyogenes strains contributing to the pathogenic and causing disease potential of this pathogen. So far, many aspects of T. pyogenes pathogenesis are unknown. In this study, expression levels of plo, fimA, nanH and cbpA genes encoding pyolysin, fimbriae, neuraminidase and collagen-binding protein, respectively in T. pyogenes isolated from totally 15 metritis, mastitis and cutaneous abscesses convenience samples in response to co-culture with other pathogens including E. coli, St. dysgalactiae, S. aureus, F. necrophorum and L. plantarum strains in mice study model have been investigated. We found that expression levels of plo, fimA, nanH and cbpA genes in T. pyogenes isolates in response to co-culture with F. necrophorum and E. coli were significantly increased; however, no significant changes was seen in the level of expression of these genes in the isolates in response to co-culture with St. dysgalactiae and S. aureus. Notably, expression of all virulence factor genes was suppressed in T. pyogenes in response to co-culture with L. plantarum. We observed that L. plantarum might be used to prevent infectious diseases caused by T. pyogenes.

Genetic characterization and phylogenetic of Anaplasma capra in Persian onagers (Equus hemionus onager).

Anaplasma spp. are among the most recognized arthropod-borne infectious agents. Although the novel A. capra has been isolated from wildlife, livestock, and hard ticks from many parts of the world, there is no report regarding the identification of this pathogen from equines and little is known about the epidemiology of A. capra in Equidae. In this study, A. capra was identified in two out of ten blood specimens of wild onagers (Equus hemionus onager) during a routine health check-up in Semnan, Iran by light microscopy and molecular analyses while other pathogens were not detected. First, inclusions on RBC's were observed in two blood smears by light microscopy. Then, the blood specimens of both animals were analyzed by realtime-PCR for Anaplasma, Ehrlichia, and Theileria infections. A 1400 bp sequence of 16S rRNA belonging to Anaplasmataceae and 874 bp fragment for groEL gene for A. capra were amplified in Anaplasma positive samples and sequenced. Preliminary BLAST analysis of sequenced fragments showed high homology to A. capra strains in GenBank database. Finally, nested PCR and restriction enzyme fragment length polymorphism techniques confirmed the pathogen as A. capra. To the best of our knowledge, this study has reported the occurrence of A. capra in wild onagers for the first time and suggests that equines could be infected with this pathogen and act as reservoirs for A. capra.

Oral Abscess Caused by Chryseobacterium indologenes in Ball Python (Python regius); A Case Report.

Chryseobacterium indologenes is an opportunistic pathogen isolated from human infections and, rarely, from some aquatic animals. A 3-year-old male ball python (Python regius) was admitted to the veterinary clinic by a pet owner because of acute respiratory and swallowing failure. During physical examinations, oral secretions and abscesses were observed in the mouth cavity and throat of the animal. After microbiological analysis including isolation, identification, and 16s rRNA sequencing, C. indologenes was detected as the main cause of the oral abscess in this case. Phylogenetic relatedness analysis showed a close relationship between this isolate and other strains isolated from human infections. Antimicrobial susceptibility testing revealed that the isolate was multi-drug resistant. However, it was very sensitive to minocycline, ceftazidime, and tetracycline. The patient was treated by antibiotic therapy and completely recovered after two weeks. To the best of our knowledge, this is the first incidence of C. indologenes in an oral abscess in a ball python. As a result we would consider this organism as an opportunistic animal pathogen with zoonotic potentiality.

Genetic diversity and antifungal susceptibility of Candida albicans isolates from Iranian HIV-infected patients with oral candidiasis.

OBJECTIVE: The objectives of this study were to investigate the antifungal susceptibility and genetic diversity of Candida albicans isolated from HIV+ patients with oropharyngeal candidiasis. A total of 50 C. albicans isolates were cultured on Sabouraud glucose agar containing chloramophenicol. The antifungal susceptibility of the isolates against fluconazole, clotrimazole, nystatin, amphotericin B, ketoconazole and flucytosine was assessed using disc diffusion method. The genetic diversity of C. albicans isolates was determined using random amplified polymorphic DNA marker. RESULTS: The inhibition zones ranged from 4 ± 1.8 to 40 ± 3.8 mm for fluconazole, 7 ± 1.0 to 37 ± 1.8 mm for ketoconazole, 14 ± 0.8 to24 ± 0.8 mm for amphotericin B, 25 ± 0.0 to 33 ± 0.0 mm for nystatin and 7 ± 4.2 to 40 ± 0.0 mm for clotrimazole. At 90% similarity, three distinct groups were observed. The smallest cluster composed of 3 isolates, whereas the largest one composed of 17 isolates. 32% (16/50), 28% (14/50) and 14% (7/50) were resistant to fluconazole, ketoconazole and clotrimazole, respectively.

Fabrication of chitosan-polyethylene glycol nanocomposite films containing ZIF-8 nanoparticles for application as wound dressing materials.

Biocompatible nanocomposite films based on chitosan (CS) and polyethylene glycol (PEG) polymers containing cephalexin (CFX) antibiotic drug and zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) were designed and fabricated to develop wound dressing materials capable of controlled drug release. Swelling experiment was performed in three acidic, neutral, and alkaline solutions. The tensile strength test reflected that upon increasing the NPs loading within the films, the tensile strength was enhanced but the elongation at break was diminished. The release of the CFX was intensively increased within approximately 3, 8, and 10 h (burst release) in acidic, neutral, and alkaline media, respectively while after that the CFX was smoothly released over time (sustained release). The antibacterial activities of all films were examined against Gram-positive (S. aureus, B. cereus) and Gram-negative (E. coli, P. aeruginosa, and Acinetobacter) bacteria frequently found in the infected wounds. Moreover, the MTT assay revealed that all films had high cell viabilities towards the L929 fibroblast cells confirming these nanocomposites could be used as favorable wound dressing materials. Finally, the film containing 4% ZIF-8 NPs (film 5) was chosen as the best sample due to it revealed appropriate mechanical properties, swelling, drug release and cell viability among all samples examined.

Repetitive sequences based on genotyping of Candida albicans isolates obtained from Iranian patients with human immunodeficiency virus.

OBJECTIVES: Candidiasis infection caused by Candida albicans has been known as a major problem in patients with immune disorders. The objective of this study was to genotype the C. albicans isolates obtained from oral cavity of patients with positive human immunodeficiency virus (HIV(+)) with or/and without oropharyngeal candidiasis (OPC). MATERIALS AND METHODS: A total of 100 C. albicans isolates from Iranian HIV(+)patients were genotyped using specific PCR primers of the 25S rDNA and RPS genes. RESULTS: The frequencies of genotypes A, B and C which were achieved using 25S rDNA , were 66, 24 and 10 percent, respectively. In addition, genotypes D and E were not found in this study. Each C. albicans genotype was further classified into four subtypes (types 2, 3, 2/3 and 3/4) by PCR amplification targeting RPS sequence. CONCLUSION: In general, genotype A3 constituted the majority of understudy clinical isolates obtained from oral cavity of Iranian HIV(+) patients.

Genetic characterization of Escherichia coli O157:H7 strains isolated from the one-humped camel (Camelus dromedarius) by using microarray DNA technology.

From the Camelidae family members, several serotypes of Escherichia coli (E. coli) have recently been isolated from diarrhoeic and non-diarrhoeic faecal samples. To date Shiga toxin-producing E. coli (STEC) strains have never been typed in one-humped camel (Camelus dromedarius). In the present study, two E. coli O157:H7 strains isolated from sick dromedaries were investigated. Virulence gene profiles were determined using a custom E. coli virulence DNA microarray, composed of 70-mer oligonucleotide probes targeting 264 virulence or related genes of known E. coli pathotypes. Both strains displayed positive hybridization signals for the Locus of enterocyte effacement (LEE) gene probes (ler, eae, espA, espB, tir genes), two Shiga toxin probes (stx1 and stx2), the O157 O-antigen specific probe, various virulence plasmid (pO157) probes like katP in addition to other accessory virulence genes characterized in STEC.