Bacterial Coverage Research Articles

Durable Antimicrobial Microstructure Surface (DAMS) Enabled by 3D-Printing and ZnO Nanoflowers.

A. Numerous studies have been trying to create nanomaterials based antimicrobial surfaces to combat the growing bacterial infection problems. Mechanical durability has become one of the major challenges to applying those surfaces in real life. In this study, we demonstrate the Durable Antimicrobial Microstructures Surface (DAMS) consisting of DLP 3D printed microstructures and zinc oxide (ZnO) nanoflowers. The microstructures serve as a protection armor for the nanoflowers during abrasion. The antimicrobial ability was tested by immersing in 2E8 CFU/mL Escherichia coli ( E. coli ) suspension and then evaluated using electron microscopy. Compared to the bare control, our results show that the DAMS reduces bacterial coverage by more than 90% after 12 hrs of incubation and approximately 50% after 48 hrs of incubation before abrasion. Importantly, bacterial coverage is reduced by approximately 50% after 2 min of abrasion with a tribometer, and DAMS remains effective even after 6 min of abrasion. These findings highlight the potential of DAMS as an affordable, scalable, and durable antimicrobial surface for various biomedical applications.

Responsive antibacterial surface based on looped poly(methacrylic acid)

The adhesion of bacteria to surfaces poses a significant challenge to public health and many industries, making the development of antibacterial surfaces an urgent issue. In this work, α,ω-bisthiol poly(methacrylic acid) (HS-PMAA-SH) was synthesized and grafted in loop conformation onto a substrate primed with polydopamine, in conjunction with Ag NPs prepared in-situ to create a pH responsive composite surface with synergistic fouling-resistant and bacterial killing and releasing capabilities. A monofunctional analogue of half the chain length, PMAA-SH, was also synthesized and used to construct the composite surface with the PMAA in linear conformation for comparison. Quartz crystal microbalance with dissipation experiments revealed that PMAA loops allowed much less protein to adsorb than their linear analogues. Confocal laser scanning microscopy results showed that both composite surfaces were effective in killing the bacteria attached due to the presence of Ag NPs, and exhibited good initial resistance to bacterial adhesion and ability to release the killed bacteria under mild conditions due to the PMAA component; the composite surface conjugated with PMAA-loop was superior to the one with PMAA-linear, presenting lower initial bacterial adhesion and higher release rates, maintaining a low bacterial coverage even after five resist/kill/release cycles. The research opens a new avenue for antibacterial surfaces that integrate fouling-resistance, bacterial killing and release functions.

Differences in microorganisms causing infection after cranial and spinal surgeries.

The primary aim of this retrospective study was to assess differences in the pathogens causing surgical site infections (SSIs) following craniectomies/craniotomies and open spinal surgery. The secondary aim was to assess differences in rates of SSI among these operative procedures. ANOVA tests with Bonferroni correction and incidence risk ratios (RRs) were used to identify differences in pathogens by surgical site and procedure using retrospective, de-identified records of 19,993 postneurosurgical patients treated between 2007 and 2020. The overall infection rates for craniotomy/craniectomy, laminectomy, and fusion were 2.1%, 1.1%, and 1.5%, respectively, and overall infection rates for cervical, thoracic, and lumbar spine surgery were 0.3%, 1.6%, and 1.9%, respectively. Craniotomy/craniectomy was more likely to result in an SSI than spine surgery (RR 1.8, 95% CI 1.4-2.2, p < 0.0001). Cutibacterium acnes (RR 24.2, 95% CI 7.3-80.0, p < 0.0001); coagulase-negative staphylococci (CoNS) (methicillin-susceptible CoNS: RR 2.9, 95% CI 1.6-5.4, p = 0.0006; methicillin-resistant CoNS: RR 5.6, 95% CI 1.4-22.3, p = 0.02); Klebsiella aerogenes (RR 6.5, 95% CI 1.7-25.1, p = 0.0003); Serratia marcescens (RR 2.4, 95% CI 1.1-7.1, p = 0.01); Enterobacter cloacae (RR 3.1, 95% CI 1.2-8.1, p = 0.02); and Candida albicans (RR 3.9, 95% CI 1.2-12.3, p = 0.02) were more commonly associated with craniotomy/craniectomy cases than fusion or laminectomy SSIs. Pseudomonas aeruginosa was more commonly associated with fusion SSIs than craniotomy SSIs (RR 4.4, 95% CI 1.3-14.8, p = 0.02), whereas Escherichia coli was nonsignificantly associated with fusion SSIs compared to craniotomy SSIs (RR 4.1, 95% CI 0.9-18.1, p = 0.06). Infections with E. coli and P. aeruginosa occurred primarily in the lumbar spine (p = 0.0003 and p = 0.0001, respectively). SSIs due to typical gastrointestinal or genitourinary gram-negative bacteria occur most commonly following lumbar surgery, particularly fusion, and are likely to be due to contamination of the surgical bed with microbial flora in the perianal area and genitourinary tract. Cutibacterium acnes in the skin flora of the head and neck increases risk of infection due to this microbe following surgical interventions in these body sites. The types of gram-negative bacteria associated with craniotomy/craniectomy SSIs suggest potential environmental sources of these pathogens. Based on the authors' findings, neurosurgeons should consider using a two-step skin preparation with benzoyl peroxide, in addition to a standard antiseptic such as alcoholic chlorhexidine for cranial, cervical, and upper thoracic surgeries. Additionally, broader gram-negative bacterial coverage, such as use of a third-generation cephalosporin, should be considered for lumbar/lumbosacral fusion surgical antibiotic prophylaxis.

Metal doped silica nanohybrids with extensive bacterial coverage for antibacterial applications exhibit synergistic activity

Nanotechnology has triumphantly overcome several barriers that have formed in modern life. Bacterial infections are a critical public health issue. They emphasized the failure of conventional treatments, high mortality and morbidity rates, antibiotic resistance, and other factors leading to the development of novel and affordable antibacterial medications. In this study, three types of metals (Ag, Cu, and Co) were doped separately into a silanol network in silica nanoparticles. The synthesized monometallic nanohybrids were combined in equal proportions to formulate bi and trimetallic nanohybrids. They were characterized structurally and morphologically. Fourier transform infrared (FTIR) and Raman spectroscopy studies were used to investigate the formation of the bonds and the pertinent peak positions. X-ray diffractograms (XRD) validated the crystalline structures of the metal nanohybrids. X-ray photoelectron spectroscopic study (XPS) confirmed the successful addition of metals to the silanol network. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images were used to characterize the morphology of nanohybrids and demonstrate their dimensions are on the nanoscale. The fraction of each metal doped in the silanol network was determined using energy dispersive spectroscopy (EDS) and atomic absorption spectrometry (AAS). To assess activity and confirm antibacterial synergy, the antibacterial activity of all synthesized nanohybrids was examined. The minimum inhibitory concentration-MIC (Ranged from 12.25 to 1560.00 μg/mL), minimum bactericidal concentration-MBC (Ranged from 197.00 to 3125.00 μg/mL), IC50 values (Ranged from 30.56 to 1683.00 μg/mL-) and fractional inhibitory concentration index (FICI) were determined and compared. Well diffusion assay was conducted against both ATCC cultures and clinical samples of gram-positive bacteria; Staphylococcus aureus (ATCC 25923), Streptococcus pneumoniae (ATCC 49619), MRSA (ATCC 33591) and gram-negative bacteria; Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC BAA 1706) and Pseudomonas aeruginosa (ATCC 27853). The highest synergistic radical scavenging performance of trimetallic nanohybrid (90.67 ± 0.095 %) was established by the DPPH (2,2 diphenyl-1-picrylhydrazil) experiment. Finally, when compared to monometallic nanohybrids, it was demonstrated that the synthesized multimetallic nanohybrids have a substantial potential as an emerging and cost-effective antibacterial agent.

Fabrication of robust, durable and integrated Janus coating for corrosion and fouling protection in marine environment

Janus membranes with different valuable characteristics and integrated structures have attracted a great interest of researches in order to achieve important breakthroughs in the related fields. However, the application of Janus membranes for development of anticorrosion coatings on metallic structures has been limited, which is due to weak interfacial bonding within the Janus structure and its vulnerability to damage. To address the aforementioned drawbacks, a novel strategy based on multifunction Janus membranes is presented. In this research, the steel is coated with polyurethane, followed by electrospinning a coating composed of polyurethane nanofibers with kaolin nanoparticles, and finally coated with epoxy resin containing modified ZnO to obtain the Janus membrane. The interface of the Janus membrane is accompanied by covalent bonds, leading to 10-fold enhancement in interface adhesion compared to the resin coating. The obtained Janus coating has a top surface that is superhydrophobic and a bottom surface that is hydrophilic, with excellent antiwetting and antibacterial properties. Moreover, the Janus coating shows outstanding barrier properties and the corresponding impedance modulus is maintained about 109 Ω•cm2 after 75 immersion days. Notably, the coating surface has retained superhydrophobicity after abrasion test with 600-grit sandpaper under a load of 1000 g for 60 m distance. The antibacterial tests have shown the Janus coating could decrease the bacterial coverage on the surface by 25 %. This study has revealed the potential of the Janus electrofibrous membrane as directly coatings on the metallic substrates for the first time, and in this way, multifunction coating with corrosion and fouling protection performances has been achieved.

Removal effect of disinfection factors in low concentration on Pseudomonas aeruginosa biofilm

Experimental model of Pseudomonas aeruginosa biofilm was established in vitro by using biofilm reactor. The aim of this study was evaluating the removal effect of two kinds of water flowing through bactericide resin on Pseudomonas aeruginosa biofilm, and exploring the effectiveness of continuous treatment with low concentration disinfection factor on dental unit waterlines. The experimental group selected 1-2 mg/L iodinated resin (IR) filtered water and bromined hydantoin resin (BHR) filtered water with the control group selecting the sterile distilled water. Biofilms were treated by using the immersion method for 3, 7, 10, 20, and 40 days. Total viable count (TVC) and laser confocal microscopy method (CLSM) were selected to evaluate the biofilm removal effect. The result of TVC showed that in group IR, the bacterial clearance after the treatment of 3, 7, 10, and 20 days was lower than 99.9% and unqualified. The bacterial clearance after the treatment of 40 days was 99.9%,which is qualified. In group BHR, it was lower than 99.9% and unqualified after the treatment of 3, 7, and 10 days. It was and 99.99%, 100.00% after the treatment of 20, 40 days, respectively. The result of CLSM showed that before treatment, Pseudomonas aeruginosa biofilm showed a sheet and mass distribution. The bacterial coverage was 19.24%±1.97%. The proportion of viable bacteria was 93.91%±1.39%, and the biofilm matrix coverage was 17.69%±1.11%. After 20 days of treatment, the biofilm was decreased in the IR group, with the biofilm bacterial coverage reducing to 6.77%±1.61%, the proportion of live bacteria reducing to 54.85%±5.65%, and the biofilm matrix coverage reducing to 2.41%±0.85%.There was significant difference from the pre-treatment and the control (F=359.996,P<0.001). No biofilm-like structure was found in the BHR group. After 40 days of treatment, there was still a small amount of biofilm matrix residue in the IR group, with no bacterial coverage observed. The biofilm matrix coverage was 0.67%±0.47% (F=1 021.373,P<0.001). No biofilm-like structure was found in the BHR group. In conclusion, the continuous application of BHR filter water has more advantages in killing microorganisms in biofilms, removing live and dead bacteria and biofilm matrix in biofilms. Treatment water containing corresponding low concentration disinfection factors can play an important role in the field of biofilm control in dental unit waterlines.

Self-Cross-Linkable Maleic Anhydride Terpolymer Coating with Inherent High Antimicrobial Activity and Low Cytotoxicity.

Developing coating materials with low cytotoxicity and high antimicrobial activity has been recognized as an effective way to prevent medical device-associated infections. In this study, a maleic anhydride terpolymer (PPTM) is synthesized and covalently attached to silicone rubber (SR) surface. The formed coating can be further cross-linked (SPM) through the self-condensation of pendent siloxane groups of terpolymer. No crack or delamination of SPM was observed after 500 cycles of bending and 7 day immersion in deionized water. The sliding friction force of a catheter was reduced by 50% after coating with SPM. The SPM coating without adding any extra antibacterial reagents can kill 99.99% of Staphylococcus aureus and Escherichia coli and also significantly reduce bacterial coverage, while the coating displayed no antimicrobial activity when maleic anhydride groups of SPM were aminated or hydrolyzed. The results of the repeated disinfection tests showed that the SR coated with SPM could maintain 87.3% bactericidal activity within 5 cycles. Furthermore, the SPM coating only imparted slight toxic effect (>85% viability) on L929 cells after 36 h of coculture, which is superior to the coating of aminated SPM conjugated with the antimicrobial peptide E6. The terpolymer containing maleic anhydride units have great potential as a flexible and durable coating against implant infections.

A New In Vitro Blood Flow Model for The Realistic Evaluation of Antimicrobial Surfaces.

Device-associated bloodstream infections can cause serious medical problems and cost-intensive post-infection management, defining a need for more effective antimicrobial coatings. Newly developed coatings often show reduced bacterial colonization and high hemocompatibility in established in vitro tests, but fail in animal studies or clinical trials. The poor predictive power of these models is attributed to inadequate representation of in vivo conditions. Here, we present a new single-pass blood flow model, with simultaneous incubation of the test surface with bacteria and freshly-drawn human blood. The flow model is validated by comparative analysis of a recently developed set of anti-adhesive and contact-killing polymer coatings, and the corresponding uncoated polycarbonate surfaces. The results confirm the model's ability to differentiate the antimicrobial activities of the studied surfaces. Blood activation data correlate with bacterial surface coverage: low bacterial adhesion is associated with low inflammation and hemostasis. Shear stress correlates inversely with bacterial colonization, especially on anti-adhesive surfaces. The introduced model is concluded to enable the evaluation of novel antimicrobial materials under in vivo-like conditions, capturing interactions between bacteria and biomaterials surfaces in the presence of key components of the ex vivo host response. This article is protected by copyright. All rights reserved.

Enhancing the Hydrophobicity and Antibacterial Properties of SiCN-Coated Surfaces with Quaternization to Address Peri-Implantitis.

Peri-implantitis is a major cause of dental implant failure. This disease is an inflammation of the tissues surrounding the implant, and, while the cause is multi-factorial, bacteria is the main culprit in initiating an inflammatory reaction. Dental implants with silicon carbonitride (SiCN) coatings have several potential advantages over traditional titanium implants, but their antibacterial efficiency has not yet been evaluated. The purpose of this study was to determine the anti-bacterial potential of SiCN by modifying the surface of SiCN-coated implants to have a positive charge on the nitrogen atoms through the quaternization of the surface atoms. The changes in surface chemistry were confirmed using contact angle measurement and XPS analysis. The modified SiCN surfaces were inoculated with Streptococcus mutans (S. mutans) and compared with a silicon control. The cultured bacterial colonies for the experimental group were 80% less than the control silicon surface. Fluorescent microscopy with live bacteria staining demonstrated significantly reduced bacterial coverage after 3 and 7 days of incubation. Scanning electron microscopy (SEM) was used to visualize the coated surfaces after bacterial inoculation, and the mechanism for the antibacterial properties of the quaternized SiCN was confirmed by observing ruptured bacteria membrane along the surface.

Minimizing bacterial adhesion on membrane: Multiscale characterization of surface modifications

The control of biofouling is required to improve membrane performance for water filtration. In this context, developing bioinspired approaches to modify membranes and give them antifouling properties is an interesting alternative. In this study, we elaborated new anti-biofouling membranes by coating them with vanillin, a natural bioactive molecule acting as a Quorum Sensing Inhibitor (QSI). The adsorption of vanillin by filtration was optimized to obtain homogeneous surface modifications. The modified membranes were then characterized in terms of physical-chemical properties: the results showed that they were more hydrophobic and exhibited a 14% decrease in pure water flux. Then, their anti-fouling properties were evaluated using complementary multiscale characterization methodologies: AFM single-cell experiments showed that vanillin adsorption had an effect on both the probability of bacterial cells to adhere to the surface, and on the force of adhesion. Direct EFM and SEM observation and adhesion assays further confirmed the effect of vanillin-modified membranes at the population-scale which showed a decrease in the bacterial coverage rate up to 50%. Altogether, it confirms the multifunctionality of vanillin-coated membranes against biofouling: reduction of bacterial initial adhesion by changing the membranes surface properties and reduction of biofilm formation by quorum sensing inhibition.

Antibiotic administration and wound complications after obstetric anal sphincter injuries.

Obstetric anal sphincter injuries (OASIS) are associated with both short-term and long-term maternal morbidity. Antibiotic administration has been shown to decrease wound complications after OASIS. However, the rate of antibiotic administration in a contemporary obstetric population is not known. To describe the rate of antibiotic administration with OASIS, to characterize factors associated with antibiotic administration on the day of delivery among women with OASIS, and to determine whether there was an association with reduced wound complications. Retrospective cohort study of women with a singleton vaginal birth complicated by OASIS between 2016 and 2021 in a single healthcare system. Any antibiotic administration on the day of delivery was collected. Wound complications (determined by ICD-10 codes) occurring within the first six months postpartum were available for patients delivering at tertiary care centers. Multivariable logistic regression analysis was used to identify factors associated with antibiotic administration and the association between antibiotics and wound complications. During the study period, 1,550 women met inclusion criteria, of whom 855 (55.2%) received antibiotics. Antibiotic administration was higher at tertiary care vs community-based hospitals (68.7 vs 26.8%, p<0.001). In the adjusted analysis, antibiotic administration was higher among women with a fourth-degree laceration (adjusted odds ratio 2.72, 95% CI 1.69-4.37) and lower among women of Asian or Pacific Islander heritage (aOR 0.88, 95% CI 0.80-0.97). At tertiary care hospitals, forty-three women (4.1%) had a wound complication, with more than 80% presenting within the first two weeks postpartum. Antibiotic use was associated with reduced rates of wound complications (aOR 0.34, 95% CI 0.13-0.91). All patients received a regimen with gram positive coverage; there was no association between type of antibiotic regimen administered and wound complication. Any antibiotic administration on the day of delivery is associated with a decreased rate of wound complications after OASIS. However, only about half of women with OASIS received antibiotics. Optimizing antibiotic administration may help to reduce the risk of complications in this population.

Insulated Interlaced Surface Electrodes for Bacterial Inactivation and Detachment.

Effective and stable antibiofouling surfaces and interfaces have long been of research interest. In this study, we designed, fabricated, and evaluated a surface coated with insulated interlaced electrodes for bacterial fouling reduction. The electrodes were printed Ag filaments of 100 μm width and 400 μm spacing over an area of 2 × 2 cm2. The insulating Ag electrode coating material was polydimethylsiloxane (PDMS) or thermoplastic polyurethane (TPU) with a thickness of 10 to 40 μm. To evaluate the antibiofouling potential, E. coli inactivation after 2 min contact with the electrified surface and P. fluorescens detachment after 15 and 40 h growth were examined. The extent of bacterial inactivation was related to the insulating material, coating thickness, and applied voltage (magnitude and AC vs DC). A high bacterial inactivation (>98%) was achieved after only 2 min of treatment at 50 V AC and 10 kHz using a 10 μm TPU coating. P. fluorescens detachment after 15 and 40 h incubation in the absence of applied potential was completed with simultaneous cross-flow rinsing and AC application. Higher AC voltages and longer cross-flow rinsing times resulted in greater bacterial detachment with bacterial coverage able to be reduced to <1% after only 2 min of rinsing at 50 V AC and 10 kHz. Theoretical electric field analysis indicated that at 10 V the field strength penetrating the aqueous solution is nonuniform (∼16,000-20,000 V m-1 for the 20 μm TPU) and suggests that dielectrophoresis plays a key role in bacterial detachment. The bacterial inactivation and detachment trends observed in this study indicate that this technique has merit for future antibiofouling surface development.

Bacteria commonly associated with central nervous system catheter infections elicit distinct CSF proteome signatures.

Cerebrospinal fluid (CSF) shunt infection is a common and devastating complication of the treatment of hydrocephalus. Timely and accurate diagnosis is essential as these infections can lead to long-term neurologic consequences including seizures, decreased intelligence quotient (IQ) and impaired school performance in children. Currently the diagnosis of shunt infection relies on bacterial culture; however, culture is not always accurate since these infections are frequently caused by bacteria capable of forming biofilms, such as Staphylococcus epidermidis, Cutibacterium acnes, and Pseudomonas aeruginosa resulting in few planktonic bacteria detectable in the CSF. Therefore, there is a critical need to identify a new rapid, and accurate method for diagnosis of CSF shunt infection with broad bacterial species coverage to improve the long-term outcomes of children suffering from these infections. To investigate potential biomarkers that would discriminate S. epidermidis, C. acnes and P. aeruginosa central nervous system (CNS) catheter infection we leveraged our previously published rat model of CNS catheter infection to perform serial CSF sampling to characterize the CSF proteome during these infections compared to sterile catheter placement. P. aeruginosa infection demonstrated a far greater number of differentially expressed proteins when compared to S. epidermidis and C. acnes infection and sterile catheters, and these changes persisted throughout the 56-day time course. S. epidermidis demonstrated an intermediate number of differentially expressed proteins, primarily at early time points that dissipated over the course of infection. C. acnes induced the least amount of change in the CSF proteome when compared to the other pathogens. Despite the differences in the CSF proteome with each organism compared to sterile injury, several proteins were common across all bacterial species, especially at day 5 post-infection, which are candidate diagnostic biomarkers.

LATE HAEMOPHILLUS ENDOCARDITIS AFTER SEPTAL CLOSURE BY AMPLATZER

Abstract Introduction Atrial septal defects are the second most frequent congenital heart diseases and their treatment of choice is the percutaneous approach. Complications associated are infrequent and are mainly related with the puncture. Other complications such as embolism or endocarditis are uncommon. Clinical case A 17-year-old woman whose only medical history of interest was an ostium secundum-type atrial septal defect that was treated percutaneously implanting a 24-mm Amplatzer septal occlude. 15 months after the procedure she came to the emergency room presenting 40°C fever and a headache. Physical examination and tests results were normal, being discharged with antibiotic treatment. She returned 24 hours later due to persistence of the same symptoms. An echocardiogram was performed, revealing an endocarditic growth and uncomplete endothelization of the amplatzer. Following 10 days of antibiogram-guided therapy with good response, she underwent surgery. The device was extracted and the defect closed. PCR was positive for H. Parainfluenzae. The patient was discharged on the 7th day with antibiotic therapy. Discussion This case is relevant due to the late presentation of IE, incomplete endothelization and to being caused by infrequent IE germ source with a negative blood culture. Despite the low prevalence of these complications, it is necessary to rule them out through imaging tests as well as microbiological tests. Appropriate length of bacterial coverage usually extends from 6 months to 1 year after implantation. Documented cases of prosthetic IE related to incorrect endothelial coverage can lead to reassessing the time period during which prophylaxis should be maintained.

Microbial DNA extraction of high-host content and low biomass samples: Optimized protocol for nasopharynx metagenomic studies.

Low microbial biomass and high human DNA content in nasopharyngeal aspirate samples hinder comprehensive characterization of microbiota and resistome. We obtained samples from premature infants, a group with increased risk of developing respiratory disorders and infections, and consequently frequent exposure to antibiotics. Our aim was to devise an optimal protocol for handling nasopharyngeal aspirate samples from premature infants, focusing on host DNA depletion and microbiome and resistome characterization. Three depletion and three DNA extraction protocols were compared, using RT-PCR and whole metagenome sequencing to determine the efficiency of human DNA removal, taxonomic profiling and assignment of antibiotic resistance genes. Protocols were tested using mock communities, as well as pooled and individual patient samples. The only extraction protocol to retrieve the expected DNA yield from mock community samples was based on a lytic method to improve Gram positive recovery (MasterPure™). Host DNA content in non-depleted aliquots from pooled patient samples was 99%. Only samples depleted with MolYsis™ showed satisfactory, but varied reduction in host DNA content, in both pooled and individual patient samples, allowing for microbiome and resistome characterisation (host DNA content from 15% to 98%). Other depletion protocols either retrieved too low total DNA yields, preventing further analysis, or failed to reduce host DNA content. By using Mol_MasterPure protocol on aliquots from pooled patient samples, we increased the number of bacterial reads by 7.6 to 1,725.8-fold compared to non-depleted reference samples. PCR results were indicative of achieved microbial enrichment. Individual patient samples processed with Mol_MasterPure protocol varied greatly in total DNA yield, host DNA content (from 40% to 98%), species and antibiotic resistance gene richness. Despite high human DNA and low microbial biomass content in nasopharynx aspirates of preterm infants, we were able to reduce host DNA content to levels compatible with downstream shotgun metagenomic analysis, including bacterial species identification and coverage of antibiotic resistance genes. Whole metagenomic sequencing of microbes colonizing the nasopharynx may contribute to explaining the possible role of airway microbiota in respiratory conditions and reveal carriage of antibiotic resistance genes.

1229. Evaluation of Colorectal and Hip/Knee Arthroplasty Surgical Site Infections at Ocean University Medical Center

Abstract Background A surgical site infection (SSI) is defined as an infection that occurs up to 30 days after surgery without an implant (or within one year if an implant is placed). The infection also must appear to be related to surgery. In 2021, there were 19 SSIs reported at Ocean University Medical Center (OUMC). These SSIs were associated with colorectal and hip/knee arthroplasty cases. The primary objective of this study is to evaluate appropriate preoperative antibiotic administration based on the type of surgical procedure. Some secondary objectives include the number of preoperative antibiotics administered and the appropriate timing of preoperative antibiotic administration. Methods A retrospective observational evaluation was conducted on patients identified to have a SSIs from January 1, 2021, to December 31, 2021. Appropriate preoperative antibiotics were defined as the administration of guideline-recommended antibiotics for the given procedure. Appropriate timing of antibiotics was defined as antibiotics administered within guideline-recommended time frames prior to procedure start time. Descriptive statistics were used to analyze the results. Results Of the 19 infections, ten were associated with colorectal procedures, and nine were associated with hip/knee arthroplasty procedures. Patients received preoperative antibiotics in 89% of the surgeries (17 of 19). We found that 71% (12 of 17) of patients received appropriate antibiotics determined by the surgical procedure. Of the five inappropriate antibiotic selection instances, two lacked appropriate bacterial coverage, while the other three covered the suspected pathogens but were not guideline-recommended agents. The timing of preoperative antibiotics was found to be appropriate in 76% of all surgeries. When assessing the overall compliance with antibiotic selection and timing, 58% (11 of 19) of cases followed all guideline recommendations. Conclusion This study has identified areas of improvement regarding the antimicrobial selection and timing, documentation process of administration, and the use of order sets to combat inappropriate prescribing of surgical antimicrobial prophylaxis. Educational materials and in-services have been provided at OUMC. Disclosures All Authors: No reported disclosures.

Biofilm Control in Flow-Through Systems Using Polyvalent Phages Delivered by Peptide-Modified M13 Coliphages with Enhanced Polysaccharide Affinity.

Eradication of biofilms that may harbor pathogens in water distribution systems is an elusive goal due to limited penetration of residual disinfectants. Here, we explore the use of engineered filamentous coliphage M13 for enhanced biofilm affinity and precise delivery of lytic polyvalent phages (i.e., broad-host-range phages lysing multiple host strains after infection). To promote biofilm attachment, we modified the M13 major coat protein (pVIII) by inserting a peptide sequence with high affinity for Pseudomonas aeruginosa (P. aeruginosa) extracellular polysaccharides (commonly present on the surface of biofilms in natural and engineered systems). Additionally, we engineered the M13 tail fiber protein (pIII) to contain a peptide sequence capable of binding a specific polyvalent lytic phage. The modified M13 had 102- and 5-fold higher affinity for P. aeruginosa-dominated mixed-species biofilms than wildtype M13 and unconjugated polyvalent phage, respectively. When applied to a simulated water distribution system, the resulting phage conjugates achieved targeted phage delivery to the biofilm and were more effective than polyvalent phages alone in reducing live bacterial biomass (84 vs 34%) and biofilm surface coverage (81 vs 22%). Biofilm regrowth was also mitigated as high phage concentrations induced residual bacteria to downregulate genes associated with quorum sensing and extracellular polymeric substance secretion. Overall, we demonstrate that engineered M13 can enable more accurate delivery of polyvalent phages to biofilms in flow-through systems for enhanced biofilm control.

Review on Population Pharmacokinetics of Amikacin in Paediatrics

Amikacin is an aminoglycoside antibiotic with a broad-spectrum bacterial coverage that is frequently utilized both as monotherapy and in combination with other antibiotics for severe bacterial infections in the paediatric population. The narrow therapeutic index of the drug and high inter-individual variabilities in drug exposure results in either drug toxicity or subtherapeutic concentrations. Thus, therapeutic drug monitoring and population pharmacokinetics are pivotal to facilitate the optimal dosage regimens in paediatrics and negate the adverse outcomes. The therapeutic goal is to maintain the target peak and trough concentrations within 30-40mg/l and &lt;5 mg/l respectively. This review aimed to summarize population pharmacokinetic considerations and the pharmacokinetic parameters of amikacin across the paediatric population.

A high-throughput integrated biofilm-on-a-chip platform for the investigation of combinatory physicochemical responses to chemical and fluid shear stress.

Physicochemical conditions play a key role in the development of biofilm removal strategies. This study presents an integrated, double-layer, high-throughput microfluidic chip for real-time screening of the combined effect of antibiotic concentration and fluid shear stress (FSS) on biofilms. Biofilms of Escherichia coli LF82 and Pseudomonas aeruginosa were tested against gentamicin and streptomycin to examine the time dependent effects of concentration and FSS on the integrity of the biofilm. A MatLab image analysis method was developed to measure the bacterial surface coverage and total fluorescent intensity of the biofilms before and after each treatment. The chip consists of two layers. The top layer contains the concentration gradient generator (CGG) capable of diluting the input drug linearly into four concentrations. The bottom layer contains four expanding FSS chambers imposing three different FSSs on cultured biofilms. As a result, 12 combinatorial states of concentration and FSS can be investigated on the biofilm simultaneously. Our proof-of-concept study revealed that the reduction of E. coli biofilms was directly dependent upon both antibacterial dose and shear intensity, whereas the P. aeruginosa biofilms were not impacted as significantly. This confirmed that the effectiveness of biofilm removal is dependent on bacterial species and the environment. Our experimental system could be used to investigate the physicochemical responses of other biofilms or to assess the effectiveness of biofilm removal methods.

Self-Patterned Nanoscale Topography of Thin Copolymer Films Prepared by Evaporative Assembly-Resist Early-Stage Bacterial Adhesion.

Biofilm formation on the surfaces of indwelling medical devices has become a growing health threat due to the development of antimicrobial resistance to infection-causing bacteria. For example, ventilator-associated pneumonia caused by Pseudomonas and Staphylococci species has become a significant concern in treatment of patients during COVID-19 pandemic. Nanostructured surfaces with antifouling activity are of interest as a promising strategy to prevent bacterial adhesion without triggering drug resistance. In this study, we report a facile evaporative approach to prepare block copolymer film coatings with nanoscale topography that resist bacterial adhesion. The initial attachment of the target bacterium Pseudomonas aeruginosa PAO1 to copolymer films as well as homopolymer films was evaluated by fluorescence microscopy. Significant reduction in bacterial adhesion (93-99% less) and area coverage (>92% less) on the copolymer films was observed compared with that on the control and homopolymer films [poly(methacrylic acid) (PMAA)─only 40 and 23% less, respectively]. The surfaces of poly(styrene)-PMAA copolymer films with patterned nanoscale topography that contains sharp peaks ranging from 20 to 80 nm spaced at 30-50 nm were confirmed by atomic force microscopy and the corresponding surface morphology analysis. Investigation of the surface wettability and surface potential of polymer films assists in understanding the effect of surface properties on the bacterial attachment. Comparison of bacterial growth studies in polymer solutions with the growth studies on coatings highlights the importance of physical nanostructure in resisting bacterial adhesion, as opposed to chemical characteristics of the copolymers. Such self-patterned antifouling surface coatings, produced with a straightforward and energy-efficient approach, could provide a convenient and effective method to resist bacterial fouling on the surface of medical devices and reduce device-associated infections.