Diatomite Dynamic Membrane Fouling Behaviour during Dewatering of Chlorella pyrenoidosa in Aquaculture Wastewater

Combined microalgal and membrane filtration could effectively treat aquaculture wastewater; however, the membrane fouling induced by extracellular organic matter (EOM) during the dewatering process is an issue. This study investigated diatomite dynamic membrane (DDM) fouling behaviour during the dewatering of Chlorella pyrenoidosa under the influence of copper ions. The results indicate that copper ion heavy metals in aquaculture wastewater significantly affected purification and algae dewatering by DDM. Aquaculture wastewater with a high copper concentration (1 and 0.5 mg/L) could induce serious DDM fluxes and cake layer filtration resistance (Rc), whereas fewer filtration fluxes were induced when aquaculture wastewater had a low copper concentration, particularly that of 0.1 mg/L, at which the Rc was lowest and the concentration effect was highest. Macromolecular organics of EOM, such as biopolymers, polysaccharides, and proteins, were responsible for DDM fouling and accumulated mostly in the slime layer, whereas only a small amount of them accumulated in the diatomite layer. The DDM rejected more protein-like organics of EOM in the slime layer when dewatering algae at low copper concentrations (<0.1 mg/L); however, when using the DDM to dewater algae at high copper concentrations, more polysaccharides of EOM were rejected (0.5 < Cu2+ < 5 mg/L). This result has significant ramifications for aquaculture wastewater treatment as well as algae separation and concentration by the DDM.

814. Successful Treatment of Cutibacterium acnes (CA) Prosthetic Device Infection (PDI) with Oral Linezolid and Rifampin (LR)

Background CA PDI is increasingly recognized. CA is felt to create a slime layer that makes infection more likely and treatment more difficult in this setting. Traditional management has included prosthetic device explantation (PDE), prolonged antibiotic treatment, and delayed reimplantation. Recent interest in the use of oral treatment regimens and single stage procedures with long duration antibiotic therapy led us to treat a series of patients with oral treatment and retained prosthesis after debridement. We report those results. Methods Sequential patients with CA PDI treated with oral therapy were identified. All patients underwent debridement of the tissue, exchange of components and/or reimplantation of the prosthetic device. Only patients with exchanges were included. PDE was excluded. MIC testing for CA isolates was obtained when possible. Initial treatment was recorded at time of surgery. LR was the treatment of choice unless toxicity developed. A minimum of a 3-month follow-up post treatment was required to be included. 6 and 12 month follow up were obtained for all patients but 1 at this time. Results 10 patients were treated (Table 1). Shoulder joint infections were most common. All patients were treated with LR. All completed a minimum of 42 days of treatment (Table 2). The medication was well tolerated. The most common adverse events were nausea. 9/10 patients with 12 month follow up had no evidence of relapse. 1/10 had no relapse at 3 months. Typical for CA infection laboratory markers for infection were not markedly elevated. Notably thrombocytopenia did not occur (Table 3). Table 1. Distribution of Prosthetic Device Infections Table 2. Duration of Treatment Table 3. Selected Laboratory Results Conclusion We demonstrated the ability to successfully treat 10/10 patients with CA PDI without explantation using prolonged oral treatment with LR after debridement. This combination should be considered a treatment option and explored further as a low cost, well tolerated, high value treatment approach to this difficult infection. Disclosures Ronald G. Nahass, MD, Abbvie (Grant/Research Support, Speaker’s Bureau)Alkermes (Grant/Research Support)Gilead (Grant/Research Support, Speaker’s Bureau)Merck (Grant/Research Support, Speaker’s Bureau) Kathleen H. Seneca, MSN, Abbvie (Research Grant or Support)Alkermes (Research Grant or Support)Gilead (Speaker’s Bureau)

Optimum cultural conditions to achieve the best biofilm formation and high level icaA transcription by Staphylococcus aureus

Background The aim of this study was to investigate the influences of different broth culture media supplemented with glucose, on the biofilm formation and ica expression of Staphylococcus aureus. The phenotypic ability to adhere to a polystyrene surface and to produce slime layer were evaluated using microtiter plate test (MtP) and Congo red tube test, respectively. Using PCR, the presence of ica locus in S. aureus strains was confirmed and subsequently, quantitative real-time RT-PCR was performed to investigate transcription of icaA in various media including Tryptic soy broth (TSB), Brain-heart infusion broth (BHIB), (Nutrient broth) NB and (Muller-Hinton broth) MHB contained 0, 0.25, 0.5, 1 and 2% glucose. Results Our results showed that although all of the studied strains adhered to the wells of polystyrene microtiter plates, the optimum rate of biofilm formation was observed for TSB medium contained 1% glucose, but biofilm formation was not significantly different in NB, MHB and BHIB media. Supplementation of all media with 1% glucose led to the highest production of biofilm formation and in all of media transcription of icaA was increased with glucose addition to one present. Conclusions The results of the present study indicated that TSB medium supplemented with 1% glucose was the most appropriate medium for evaluation of biofilm formation by S. aureus isolates.

Oryzicola mucosus gen. nov., sp. nov., a Novel Slime Producing Bacterium Belonging to the Family Phyllobacteriaceae Isolated From the Rhizosphere of Rice Plants

A novel Gram-stain negative, asporogenous, slimy, rod-shaped, non-motile bacterium was isolated from the root samples collected from rice field located in Ilsan, South Korea. Phylogenetic analysis of the 16S rRNA sequence of the bacterium revealed a close proximity to Tianweitania sediminis Z8T (96.5%) followed by genera Mesorhizobium (96.4-95.6%), Aquabacterium (95.9-95.7%), Rhizobium (95.8%) and Ochrobactrum (95.6%). Strain ROOL2T produced white slime on R2A agar plates and grew optimally at 30℃ in the presence of 1-6% (w/v) NaCl and at pH 7.5. The major respiratory quinone was ubiquinone-10 and the major cellular fatty acids were C18 :1ω7c, summed feature 4 (comprising iso-C17:1 I and/or anteiso-C17:1 B) and summed feature 8 (comprising C18:1ω6c and/or C18:1ω7c). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmethylethanolamine, phosphatidylglycerol, one unidentified aminolipid and two unidentified lipids. The assembled draft genome of strain ROOL2T had 28 contigs with N50 values of 656,326 nt, total length of 4,894,583 bp and a DNA G+C content of 61.5%. The average amino acid identity (AAI) values of strain ROOL2T against the genomes of related members belonging to the same family were below 68%, is below the suggested threshold for genera boundaries. The ANI and dDDH values between the strain ROOL2T and the type strains of phylogenetically related species were 61.8-76.3% and 19.4-21.1%, respectively. Strain ROOL2T only produced carotenoid-type pigment when grown on LB agar but doesn’t produced slime material, in opposite they produced slime materials on R2A and doesn’t produces carotenoid-type pigments. The slime layer protects its inhabitants from environmental dangers such as desiccation and antibiotics. Strain ROOL2T produced indole acetic acid (IAA) in the presence of tryptophan. Bacterial IAA is a crucial phytohormone in plant growth and development. Striking gene clusters for indole-3-glycerol phosphatase and tryptophan synthase were found in the genome of strain ROOL2T. The genotypic and phenotypic characteristics indicated that strain ROOL2T represents a novel genus belonging the family Phyllobacteriaceae, for which the name Oryzicola mucosus gen. nov., sp. nov. is proposed. The type strain is ROOL2T (KCTC 82711T = NBRC 114717T).

The deleterious relationship of Pseudomonas aeruginosa and Induced Membranes in infected non-union treatment

The Masquelet technique was originally described for the treatment of an infected non-union with an extensive bone defect where a staged protocol was needed to first eliminate an infection then secondarily bone graft a defect. Though this is a versatile technique, certain limitations/ complications must be recognized. The study was done between 2012 to 2019 at SRIHER university. 19 patients in whom the Masquelet technique has failed is taken into study. 17 male and two females, with a mean age of 31 years (range of 13 yrs. – 51 yrs.) with a mean follow up of 12 months. The 19 patients who presented with Pseudomonas aeruginosa infected non-union of the tibia and femur with bone defects underwent the Masquelet technique. All patients failed to form adequate induced membrane at the non-union site. Infected non-union with a bone defect is difficult to treat. Bone defects of 2cms can be treated by cancellous bone grafting. Defects more than 4-5cms will require specialized reconstructive procedures to prevent amputation. The two common techniques used are Ilizarov technique with bone transport and bone graft into an induced membrane as described by Masquelet. This study shows a high failure rate of the Masquelet technique with Pseudomonas infection. The most difficult issue faced by the surgeon in treating P. aeruginosa is its ability to develop resistance to multiple classes of antibiotics during the course of treating the patient. Masquelet technique is used extensively for the treatment of infective non-union. Pseudomonas secretes a slime layer that may lead to a weak or deficient formation of the induced membrane. And the elution of antibiotics may not be adequate for intramedullary osteomyelitis with pseudomonas growth. This limits the Masquelet technique in the management of infected non-union with pseudomonas infection.

Detection of icaA Gene Expression in Clinical Biofilm-Producing Staphylococcus Aureus Isolates

The pathogenicity resulting from Staphylococcus aureus infection has remarkable importance as one of the community-associated bacterial infections, due to the virulent ability of these bacteria to produce biofilms. This study was designed to detect biofilm production in clinical isolates from samples of wounds and urinary tract infections. The expression levels of the icaA gene that is responsible of slime layer production in biofilms was compared in isolates with different biofilm producing capabilities. Fifty seven samples that included 32 samples from urine and 25 samples from wounds were collected from Alwasti Hospital, Al-Kindi Teaching Hospital, and Alzahraa Clinic, Baghdad, Iraq. The bacteria was identified according to biochemical tests, API20 strip test, and PCR assay. The results of 16S rRNA PCR detection revealed that nine isolates were identified as S. aureus. The biofilm assay showed that 46.15% of the isolates were strong biofilm producers, 46.15% had moderate ability to produce biofilm, and 7.70% were weak producers. Quantitative PCR assay was carried out on three isolates with different biofilm-producing abilities. The results demonstrated that the strong biofilm-producing isolates had significantly higher (P ≤0.01) gene expression level (6.508) compared with the moderate (1.624) and the weak (1.231) isolates.

Staphylococcal slime layers and biofilm from different origins

ABSTRACT: The genus Staphylococcus comprises some of the most important pathogenic bacteria for both humans and animals. It is responsible for bovine mastitis and canine otitis, besides being present in the microbiota of animals and as a contaminant in food. Its pathogenesis is related to the formation of capsule and biofilm, which contribute to its infectivity. The objective of this study was to observe the production of slime layer and formation of biofilm, which are related to the resistance to antimicrobial agents and presence of icaA and icaD genes, in 41 isolates of Staphylococcus spp. from different origins, provided by the Universidade Federal de Pelotas (UFPEL), Laboratório Regional de Diagnóstico (LRD). Strains of Staphylococcus spp. were cultivated in Congo red agar for capsule detection. Biofilm formation was detected using the 96-well microplate testing. Antimicrobial susceptibility testing was performed using the plate diffusion method. Part of the analyzed samples produced slime layer (36.6%) and formed biofilm (17.1%). However, six of those that formed biofilms were susceptible to the eight antibiotics tested in the antibiogram. In tests to determine the minimum bactericidal and inhibitory concentrations, gentamicin resistance of biofilm-forming strains was greater than that of non-forming strains. Ampicillin was the least effective antimicrobial drug (51%), followed by tetracycline (71%), neomycin (73%), and erythromycin (73%). Some isolates presented the icaA (6) and icaD (11) genes. Therefore, we suggested that the origin of an isolate can determine its expression of virulence factor and resistance to certain antibiotics.

Isolation and Identification of Methicillin Resistance Staphylococcus aureus and Detection their Ability to the Production of Virulence Factors

* Objectives: Isolation and Identification of S.aureus and study their susceptibility to the production of virulence factors. * Methods: A total of 50 clinical specimens of Staphylococcus aureus isolates were collected in AL- Najaf AL-Asharaf governorate during the period of (10/10/2013-20/1/2014) by the cultural characteristic colonies, microscopic for cells, biochemical tests, antibiotics susceptibility test to Staphylococcus aureus using an antibiotic diffusion disc assay, in addition to studying the virulence factors produced from S.aureus . * Results: The results show that the Staphylococcus aureus resistant to methicillin formed 70% and 30% of isolates were sensitive to the same antibiotics. Tested 10 isolates to methicillin-resistant for their efficiency in forming the highest inhibitory areas for testing their sensitivity to other antibiotics used, the results show S.aureus resistant to penicillin about 100%, while there is no resistance to CO-Trimethoprim because it was sensitive completely 100%. The susceptibility investigated of Staphylococcus aureus resistance methicillin isolates to the production of biofilm and slime layer with using both tube method and growth on Congo red agar respectively. Ten isolates of S.aureus were tested based on resistance to methicillin and their high susceptibility to the production of the biofilm and the slime layer. * Conclusion: So we conclude, they have Staphylococcus aureus is highly resistant to β- Lactam antibiotics and the CO-trimethoprim is the most effective in the inhibiting growth of this bacteria. In addition to its ability to produce virulence factors. The increase cause bacterial resistance to our local isolates may be due to the frequent use of antibiotics, which allowed for increased bacterial resistance to various antibiotics.

Evidence-Based Decision Making to Underpin the Thresholds in New Zealand's Craft Risk Management Standard: Biofouling on Vessels Arriving to New Zealand

Vessel biofouling is a significant pathway for the introduction of nonindigenous marine species (NIMS). New Zealand is the first nation to regulate the vessel biofouling pathway, with controls scheduled to come into force in May 2018. The Craft Risk Management Standard (CRMS): Biofouling on Vessels Arriving to New Zealand specifies the hull fouling thresholds that vessels must meet; and here, we present the evidence-based decisions that underpin these thresholds.Under the CRMS, a vessel must arrive in New Zealand with a “clean hull,” the thresholds for which are governed by the intended duration of a vessel's stay in New Zealand. For example, long-stay (≥21 days) vessels must meet a more stringent standard of hull cleanliness due to the increased likelihood of release and establishment of NIMS. While setting a clean hull threshold at “slime layer only” can be tractable when vessels operate within the specifications of antifouling coatings, incidental amounts of macrofouling can establish even under the best management practices. Because of such instances, the thresholds within the CRMS were designed to allow for the presence of some macrofouling species, albeit with restrictions to minimize biosecurity risk. These thresholds are intended to limit species richness and to prevent successful reproduction and settlement of the allowed taxonomic groups while considering the practicality and feasibility of implementation.The difficulties of managing biofouling on different areas of the hull are acknowledged within these thresholds. For example, a greater tolerance of macrofouling has been allowed for niche areas due to the difficulties in preventing biofouling on these areas.