293 research outputs found
Free-floating aggregate and single cell-initiated biofilms of Staphylococcus aureus
No full textPeriprosthetic joint infection (PJI) occurring after artificial joint replacement is a major clinical issue requiring multiple surgeries and antibiotic interventions. Staphylococcus aureus is the common bacteria responsible for PJI. Recent in vitro research has shown that staphylococcal strains rapidly form free-floating aggregates in the presence of synovial fluid (SF) with biofilm-like resistance to antimicrobial agents. However, the development of biofilms formed from these aggregates under shear have not been widely investigated. Thus, in this study, we examined the progression of attached biofilms from free-floating aggregates. Biofilms were grown for 24 hours in flow cells on titanium discs after inoculating with either pre-aggregated or single planktonic cells. Image analysis showed no significant difference between the biofilm formed from aggregates vs. the planktonic cells in terms of biomass, surface area, and thickness. Regarding antibiotic susceptibility there was 1 and 2 log reductions in biofilms formed from single cells and aggregates respectively when treated with vancomycin for 24 hours. Thus, this study demonstrates the formation of biofilm from free-floating aggregates follows a similar developmental time-period and shows similar antibiotic tolerance as more traditionally inoculated in vitro flow cell biofilms
The influence of patterned surface features on the accumulation of bovine synovial fluid induced aggregates of Staphylococcus aureus
No full textPeriprosthetic joint infection (PJI) after joint replacement is a major clinical issue requiring multiple surgeries and antibiotic interventions. Recent in vitro research has shown that PJI staphylococcal strains rapidly form antibiotic resistant free-floating aggregates in the presence of bovine synovial fluid (BSF). Staphylococcal aggregates are also present in human PJI joint fluid. However, the influence of surface roughness and fluid shear on the attachment and retention of such aggregates to surfaces is not known. Our aim was to assess how surface roughness and fluid shear stress influenced the attachment and retention of S. aureus BSF mediated aggregates on smooth and rough patterned titanium in flow cells compared to non-aggregated cells. S. aureus attachment of aggregates was significantly greater than single cells but was independent of surface roughness, however on the patterned surfaces aggregates preferentially accumulated in the grooves. Fibrous components in the BSF were also colocalized with the grooves. After a 24 hr attachment and incubation period different shear stresses were applied. There was significant detachment from flat surface at 1 mL/min (τw = 0.03 Pa) but minimal detachment from the patterned surfaces, even at flow rates as high as 13.9 mL/min (τw = 0.42 Pa). The retention of bacterial aggregates and biofilm by rough surfaces exposed to shear might be an important consideration of the colonization location on orthopedic implants which can have a wide range of roughness and surface features as well as influencing efficacy of shear-based debridement methods such as pulse lavage
Description of a new species of Anthocoris (Hemiptera: Heteroptera: Anthocoridae) from southern India, associated with striped mealybug on purple orchid tree
No full textYamada, Kazutaka, Ballal, Chandish R., Gupta, Tripti, Poorani, Janakiraman (2010): Description of a new species of Anthocoris (Hemiptera: Heteroptera: Anthocoridae) from southern India, associated with striped mealybug on purple orchid tree. Acta Entomologica Musei Nationalis Pragae (suppl.) 50 (2): 415-424, DOI: http://doi.org/10.5281/zenodo.446815
sj-xlsx-1-jtr-10.1177_00472875241228498 – Supplemental material for Airline Social Media Recovery Satisfaction: Has COVID Changed Everything?
No full textSupplemental material, sj-xlsx-1-jtr-10.1177_00472875241228498 for Airline Social Media Recovery Satisfaction: Has COVID Changed Everything? by Tripti Ghosh Sharma, Mahima Gupta, Vinu Cheruvil Thomas and Bharadhwaj Sivakumaran in Journal of Travel Research</p
Biotechnological Approaches in Coconut Processing
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Figs. 1–6 in Description of a new species of Anthocoris (Hemiptera: Heteroptera: Anthocoridae) from southern India, associated with striped mealybug on purple orchid tree
No full textFigs. 1–6. Anthocoris muraleedharani Yamada, sp. nov., paratypes, male (1–2, 5–6) and female (3–4). 1 – head and pronotum, dorsal view; 2–3 – antennae; 4 – left fore wing, dorsal view; 5 – ostiolar peritreme and evaporatorium, left lateroventral view; 6 – abdominal sterna II–III, ventral view. Scale bars = 0.5 mm for 1–4, 6; 0.1 mm for 5.Published as part of Yamada, Kazutaka, Ballal, Chandish R., Gupta, Tripti & Poorani, Janakiraman, 2010, Description of a new species of Anthocoris (Hemiptera: Heteroptera: Anthocoridae) from southern India, associated with striped mealybug on purple orchid tree, pp. 415-424 in Acta Entomologica Musei Nationalis Pragae (suppl.) 50 (2) on page 417, DOI: 10.5281/zenodo.446815
sj-pdf-1-vmj-10.1177_1358863X211033649 – Supplemental material for Exercise therapy referral and participation in patients with peripheral artery disease: Insights from the PORTRAIT registry
No full textSupplemental material, sj-pdf-1-vmj-10.1177_1358863X211033649 for Exercise therapy referral and participation in patients with peripheral artery disease: Insights from the PORTRAIT registry by Tripti Gupta, Patrick Manning, Dhaval Kolte, Kim G Smolderen, Nancy Stone, Jessica G Henry, Jingyan Wang, Kensey L Gosch, Christopher J White, John Spertus and J Dawn Abbott in Vascular Medicine</p
Staphylococcus aureus aggregates on orthopedic materials under varying levels of shear stress
No full textPeriprosthetic joint infection (PJI) occurring after artificial joint replacement is a major clinical issue requiring multiple surgeries and antibiotic interventions. Staphylococcus aureus is the bacterium most commonly responsible for PJI. Recent in vitro research has shown that staphylococcal strains rapidly form aggregates in the presence of synovial fluid (SF). We hypothesize that these aggregates provide early protection to bacteria entering the wound site, allowing them time to attach to the implant surface, leading to biofilm formation. Thus, understanding the attachment kinetics of these aggregates is critical in understanding their adhesion to various biomaterial surfaces. In this study, the number, size, and surface area coverage of aggregates as well as of single cells of S. aureus were quantified under various conditions on different orthopedic materials relevant to orthopedic surgery: stainless steel (316L), titanium (Ti), hydroxyapatite (HA), and polyethylene (PE). It was observed that, regardless of the material type, SF-induced aggregation resulted in reduced aggregate surface attachment and greater aggregate size than the single-cell populations under various shear stresses. Additionally, the surface area coverage of bacterial aggregates on PE was relatively high compared to that on other materials, which could potentially be due to the rougher surface of PE. Furthermore, increasing shear stress to 78 mPa decreased aggregate attachment to Ti and HA while increasing the aggregates' average size. Therefore, this study demonstrates that SF induced inhibition of aggregate attachment to all materials, suggesting that biofilm formation is initiated by lodging of aggregates on the surface features of implants and host tissues.</p
Killing of a multispecies biofilm using a gram-negative and gram-positive targeted antibiotic released from high purity calcium sulfate beads
No full textBackground: multispecies biofilm orthopedic infections are more challenging to treat than mono-species infections. In this in-vitro study, we aimed to determine if a multispecies biofilm, consisting of Gram positive and negative species with different antibiotic susceptibilities could be treated more effectively using high purity antibiotic-loaded calcium sulfate beads (HP-ALCSB) containing vancomycin (VAN) and tobramycin (TOB) in combination than alone. Methods: three sets of species pairs from bioluminescent strains of Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA) and clinical isolates, Enterococcus faecalis (EF) and Enterobacter cloacae were screened for compatibility. PA+EF developed intermixed biofilms with similar cell concentrations and so were grown on 316L stainless steel coupons for 72 h or as 24 h agar lawn biofilms and then treated with HP-ALCSBs with single or combination antibiotics and assessed by viable count or bioluminescence and light imaging to distinguish each species. Replica plating was used to assess viability. Results: the VAN+TOB bead significantly reduced the PA+EF biofilm CFU and reduced the concentration of surviving antibiotic tolerant variants by 50% compared to single antibiotics. Conclusion: the combination of Gram-negative and positive targeted antibiotics released from HP-ALCSBs may be more effective in treating multispecies biofilms than monotherapy alone
Mapping bacterial biofilm on features of orthopedic implants in vitro
No full textImplant-associated infection is a major complication of orthopedic surgery. One of the most common organisms identified in periprosthetic joint infections is Staphylococcus aureus, a biofilmforming pathogen. Orthopedic implants are composed of a variety of materials, such as titanium, polyethylene and stainless steel, which are at risk for colonization by bacterial biofilms. Little is known about how larger surface features of orthopedic hardware (such as ridges, holes, edges, etc.) influence biofilm formation and attachment. To study how biofilms might form on actual components, we submerged multiple orthopedic implants of various shapes, sizes, roughness and material type in brain heart infusion broth inoculated with Staphylococcus aureus SAP231, a bioluminescent USA300 strain. Implants were incubated for 72 h with daily media exchanges. After incubation, implants were imaged using an in vitro imaging system (IVIS) and the metabolic signal produced by biofilms was quantified by image analysis. Scanning electron microscopy was then used to image different areas of the implants to complement the IVIS imaging. Rough surfaces had the greatest luminescence compared to edges or smooth surfaces on a single implant and across all implants when the images were merged. The luminescence of edges was also significantly greater than smooth surfaces. These data suggest implant roughness, as well as large-scale surface features, may be at greater risk of biofilm colonization.</p
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