Use of MALDI-TOF for identification and surveillance of gram-negative bacteria in captive wild psittacines

Microbiological studies of the sanitary and health status of psittacine birds that will be reintroduced is important in evaluating whether these animals act as carriers of pathogenic agents to other animals and humans. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a faster and more accurate method to identify bacteria than conventional microbiology methods. The aim of this study was to evaluate the health status of psittacines housed in captivity, by assessment of Gram-negative bacteria from fecal microbiota through MALDI- TOF MS identification. The results indicate high frequency of Gram-negative bacteria in feces (96.5%), especially from the Enterobacteriaceae family (88.7%). The most prevalent bacteria were Escherichia coli (39.0%), Proteus vulgaris (12.2%), Klebsiella spp. (12.1%) and Raoultella ornithinolytica (8.7%). Proteus hauseri, Citrobacter spp., Morganella morgannii, Providencia rettgeri, Enterobacter spp. and Escherichia hermannii were isolated with lower frequency. . All these agents are potentially pathogenic for parrots and can cause systemic infections in other animals and humans. These findings reinforce that MALDI- TOF MS proved to be a rapid and accurate method of identification of the microorganism and evaluation of the health status of psittacines, providing relevant data to assist decision-making regarding the sanitary protocols in wildlife centers, and possible future reintroduction of wild birds.

Taxonomic characteristics of micro-organisms isolated from the Baikal seal

The relevance of the ecological problem of the mass death of the Baikal seal (Pusa sibirica Gm.) forces researchers to establish causes of this phenomenon. The article presents the results of microbiological studies of swabs isolated from the nasal, oral cavities and rectum. The taxonomic characteristics of microorganisms and their virulence were studied. 14 Baikal seals found in the nerpinaria of Listvyanka were tudied. It was established that in the seal there are the following microorganisms: Clostridium perfringens, Escherichia coli, Enterococcus faecalis, Staphylococcus warneri, Pseudomona aeruginosa, Staphylococcus epidermidis, Staphylococcus aureus, Proteus hauseri, Proteus vulgaris bellisella, Proteus migarisella, rabitemorganii, Psychrobactersanguinis, Enterobacter cloacae. When studying the virulence of microorganisms, it was found that 58% of the strains do not cause the death of laboratory animals, they are mainly the representatives of opportunistic microflora. 42% of the strain were pathogenic, of which two strains of Plesi omonas shigelloides and 42 strains of Clostridium perfringens were identified.

Chemical composition of hyssop cv. 'Domaći ljubičasti' essential oil and its antimicrobial activity

Hyssop (Hyssopus officinalis L., Lamiaceae) is a perennial shrub or subshrub violet-blue flowers in verticillasters and spicy taste with a pungent flavour. Besides being used as a culinary herb for flavouring and food preservation, this plant is also an ornamental, bee attracting plant and a traditional remedy for respiratory diseases and digestive disturbances. Hyssop is an essential oil-bearing plant, and its essential oil (Hyssopi aetheroleum) is used in the pharmaceutical, perfume and cosmetics industries as well as in aromatherapy. The objective of this study was to determine the chemical composition of essential oil of hyssop CV. "Domaći ljubičasti", grown in Serbia, and investigate its antimicrobial activity against 16 bacteria, mainly pathogens in the food industry. A total of 61 compounds were detected in the hyssop essential oil. The bicyclic monoterpene ketones CIS-pinocamphone (43.8%) and trans-pinocamphone (18.3%) were the most abundant, comprising 62.1%, followed by b-pinene (6.3%) and pinocarvone (6.1%). Hyssop essential oil expressed antibacterial activity against: Staphylococcus aureus, Escherichia coli, Bacillus cereus, Proteus hauseri, Listeria monocytogenes, Rhodococcus equi, Listeria ivanovii, Salmonella Enteritidis, Enterococcus faecalis, Listeria innocua and Bacillus spizizenii. Hyssop essential oil did not express antibacterial activity against Pseudomonas aeruginosa, Salmonella Typhimurium, Klebsiella aerogenes and Staphylococcus epidermidis. Results of this study show that hyssop essential oil has potential for using as natural supplement for control of foodborne diseases of microbiological origin, as well as flavor compositions (herbaceous, camphor-like odour with warm and spicy undernotes), especially for meat products, sauces, soups and seasonings.

The Biotechnological Potential of Pediococcus spp. Isolated from Kombucha Microbial Consortium

In the past decade, the probiotic market has grown rapidly, both for foods and supplements intended to enhance wellness in healthy individuals. Different lactic acid bacteria (LAB), especially Lactobacillus spp., of different origins have already been used to develop commercial probiotic products. Nowadays, LAB new alternative sources, such as non-dairy fermented food products, are being exploited. One such source is Kombucha, a fermented low-alcohol beverage made of tea leaves. In this regard, we tested seven Pediococcus spp. strains isolated from a local industrial Kombucha for their biotechnological potential. Two, out of the seven isolates, identified as Pediococcus pentosaceus (L3) and Pediococcus acidiliactici (L5), were selected as successful candidates for the food industry, due to their probiotic and technological properties. In regard to their resistance in the gastro-intestinal tract, both selected strains were tolerant to a pH of 3.5, presence of 0.3% pepsin, and 0.5% bile salt concentration. On the antagonistic side, the fresh suspension of selected isolates had high inhibitory activity against pathogenic bacteria, such as Salmonella enterica Typhimurium, Listeria monocytogenes, Listeria ivanovii, Bacillus cereus, Proteus hauseri, and methicillin resistant Staphylococcus aureus. In addition, moderate to high inhibitory activity was noticed against foodborne molds (e.g., Penicillium expansum and Penicillium digitatum). These safety issues were supported by their negative hemolytic activity and good antioxidant potential (56–58%). Selected isolates were sensitive to ampicillin, penicillin, erythromycin, and lincomycin, while a broad range of other antibiotics were not effective inhibitors. On the technological side, both strains tolerated 5% NaCl and, during the freeze-drying process, had a good survival rate (86–92%). The selected Pediococcus strains have proven properties to be used for further development of functional products.

Isolation, Identification, and Antibiotics Susceptibility Determination of Proteus Species Obtained from Various Clinical Specimens in Erbil City

Fifty-two Proteus isolates, (47) Proteus mirabilis, (4) Proteus vulgaris, and (1) Proteus hauseri are being isolated from (200) clinical specimens taken from patients admitted to different hospitals in Erbil city/Kurdistan region of Iraq. Specimens were of urine, wounds swabs, burn swabs, vaginal swabs, ear swabs, eye swabs, and sputum. All isolates were identified depending on cultural, morphological, biochemical characteristics, and confirmatory VITEK 2 system. Furthermore, VITEK 2 (antibiotic susceptibility testing) panel was used to determine the antibiotic susceptibility of Proteus isolates, and the results showed that all isolates were entirely resistant to tetracycline and tigecycline (100%), but sensitive to meropenem. Furthermore, the present study reported a case of rare Proteus species – P. hauseri – isolated from a patient with urinary tract infection in Erbil City which characterized by no swarming on blood agar.

Synergistic Effects of Anionic/Cationic Dendrimers and Levofloxacin on Antibacterial Activities

Despite the numerous studies on dendrimers for biomedical applications, the antibacterial activity of anionic phosphorus dendrimers has not been explored. In our research, we evaluated the antibacterial activity of modified polycationic and polyanionic dendrimers in combination with levofloxacin (LVFX) against Gram-negative (Escherichia coli ATCC 25922, Proteus hauseri ATCC 15442) and Gram-positive (Staphylococcus aureus ATCC 6538) bacteria. In the case of Gram-negative bacteria, we concluded that a combination of dendrimers and antibiotic gave satisfactory results due to a synergistic effect. The use of fluoroquinolone antibiotics, such as LVFX, not only caused resistance in disease-causing microorganisms but also increased environmental pollution. Therefore, reduction of drug dosage is of general interest.

Microbial Biosynthesis of Antibacterial Chrysoeriol in Recombinant Escherichia coli and Bioactivity Assessment

Various flavonoid derivatives including methoxylated flavones display remarkable biological activities. Chrysoeriol is a methoxylated flavone of great scientific interest because of its promising anti-microbial activities against various Gram-negative and Gram-positive bacteria. Sustainable production of such compounds is therefore of pronounced interest to biotechnologists in the pharmaceutical and nutraceutical industries. Here, we used a sugar O-methyltransferase enzyme from a spinosyn biosynthesis gene cluster of Saccharopolyspora spinosa to regioselectively produce chrysoeriol (15% conversion of luteolin; 30 µM) in a microbial host. The biosynthesized chrysoeriol was structurally characterized using high-resolution mass spectrometry and various nuclear magnetic resonance analyses. Moreover, the molecule was investigated against 17 superbugs, including thirteen Gram-positive and four Gram-negative pathogens, for anti-microbial effects. Chrysoeriol exhibited antimicrobial activity against nine pathogens in a disc diffusion assay at the concentration of 40 µg per disc. It has minimum inhibitory concentration (MIC) values of 1.25 µg/mL against a methicillin-resistant Staphylococcus aureus 3640 (MRSA) for which the parent luteolin has an MIC value of sixteen-fold higher concentration (i.e., 20 µg/mL). Similarly, chrysoeriol showed better anti-microbial activity (~1.7-fold lower MIC value) than luteolin against Proteus hauseri, a Gram-negative pathogen. In contrast, a luteolin 4′-O-methylated derivative, diosmetin, did not exhibit any anti-microbial activities against any tested pathogen.

Kinetic study of Reactive Black 5 degradation by Fe2+/S2O82− process via interactive model-based response surface methodology

This study aimed to kinetically discover optimal conditions on characteristics of Reactive Black 5 decolorization/degradation via ferrous (Fe2+)-activated potassium persulfate (PS). Monod-like kinetics and interactive model-based response surface methodology (RSM) were applied to fitting and predict optimize treatment. Biodegradability of the intermediates was also tested by shaking culture with two species (Proteus hauseri ZMd44 and Shewanella sp. WLP72). Results showed that the optimal degradation efficiency was predicted (through RSM) as pH 3.72, (PS) = 0.39 mM, and (Fe2+) = 0.29 mM. The transformation products (dl-4-hydroxymandelic acid, benzoic acid, benzene, formic acid, oxalic acid and acetic acid) were less toxic than the original dye solution. According to those results, clean-up of dye pollutants by the Fe2+/S2O82− process is feasible as a pre-processing for the biodegradation, and the predicted optimal conditions are meaningful for further industry utilization.