Decrease In Bacterial Burden Research Articles

Postsurgical Carprofen Does Not Substantially Decrease Bacterial Growth in a Minipig Model of Staphylococcus aureus Deep Surgical Wound Infection

The use of analgesia in bacterial challenge models has been met with some controversy in the literature. Several publications suggest that the use of analgesics in infection models can interfere with the host immune response, change microenvironments subsequently altering bacterial pathogenesis, and directly act as an antimicrobial as was reported with opioids such as morphine. Any such interactions would compromise the experimental results, deterring researchers from the use of analgesia. Herein, we address the possible effect of analgesics on bacterial colonization in a Staphylococcus aureus surgical site infection model in Göttingen minipigs. Retrospectively, an expanded analgesia protocol (buprenorphine presurgery and carprofen postsurgery) was compared with a standard analgesia protocol using buprenorphine alone just before surgery. When examined statistically, the expanded analgesia protocol group was noninferior to the standard analgesia protocol group indicating there was no substantial decrease in bacterial burden when an expanded analgesia protocol was administered. Our results highlight the importance of studying the use of analgesia in all animal models of infection to determine if the analgesics will affect experimental outcomes.

Discovery of 2,9-diaryl-6-carbamoylpurines as a novel class of antitubercular agents

A series of novel 9-alkyl/aryl-2-aryl-6-carbamoylpurines were synthesized, and their activity against Mycobacterium tuberculosis strain H37Rv was assessed. The SAR analysis on the first set of derivatives, with an alkyl or aryl unit at N-9 and a phenolic unit at C-2, showed that the activity depends on the purine ring substituents at N-9 and C-2. A phenyl group at N-9 combined with a 3-hydroxyphenyl or 4-hydroxyphenyl at C-2 improve the activity. The most active compound of this set has a phenyl group at N-9 and a 4-hydroxyphenyl group at C-2, displaying an IC90 = 1.2 μg/mL and a selectivity index higher than 25.5. This compound served as a Hit to design the second set of derivatives. A phenyl group at N-9 was maintained, and the group at C-2 was diversified. The SAR analysis showed that the aryl unit at C-2 must have an oxygen or nitrogen atom bonded in the para position. A proton, a small alkyl or a substituted aryl group may also be bonded to the oxygen. The compound with the 4-methoxyphenyl group at C-2, 1Bd, exhibits the highest activity with an IC90 < 0.19 μg/mL. This compound is highly potent against M. tuberculosis strain H37Rv and non-toxic for VERO mammalian cells with an SI > 153.8. Compound 1Bd was also non-cytotoxic against primary macrophage cultures at IC90, 2xIC90, and 10xIC90 and significantly reduced the bacterial load in M. tuberculosis-infected macrophages at the same concentrations. Compound 1Bd showed a favorable pharmacokinetic profile when administered orally, with major lung and liver accumulation. In vivo antimycobacterial efficacy of 1Bd was tested at 25 mg/kg. At the tested regimen, a decrease in bacterial burden was observed in the liver. Optimization of the treatment regimen should be performed to fully potentiate the in vivo efficacy of our lead molecule, particularly in the lung, the main target organ of M. tuberculosis.

Clofazimine nanoclusters show high efficacy in experimental TB with amelioration in paradoxical lung inflammation

The rise of tuberculosis (TB) superbugs has impeded efforts to control this infectious ailment, and new treatment options are few. Paradoxical Inflammation (PI) is another major problem associated with current anti-TB therapy, which can complicate the treatment and leads to clinical worsening of disease despite a decrease in bacterial burden in the lungs. TB infection is generally accompanied by an intense local inflammatory response which may be critical to TB pathogenesis. Clofazimine (CLF), a second-line anti-TB drug, delineated potential anti-mycobacterial effects in-vitro and in-vivo and also demonstrated anti-inflammatory potential in in-vitro experiments. However, clinical implications may be restricted owing to poor solubility and low bioavailability rendering a suboptimal drug concentration in the target organ. To unravel these issues, nanocrystals of CLF (CLF-NC) were prepared using a microfluidizer® technology, which was further processed into micro-sized CLF nano-clusters (CLF-NCLs) by spray drying technique. This particle engineering offers combined advantages of micron- and nano-scale particles where micron-size (∼5 μm) promise optimum aerodynamic parameters for the finest lung deposition, and nano-scale dimensions (∼600 nm) improve the dissolution profile of apparently insoluble clofazimine. An inhalable formulation was evaluated against virulent mycobacterium tuberculosis in in-vitro studies and in mice infected with aerosol TB infection. CLF-NCLs resulted in the significant killing of virulent TB bacteria with a MIC value of ∼0.62 μg/mL, as demonstrated by Resazurin microtiter assay (REMA). In TB-infected mice, inhaled doses of CLF-NCLs equivalent to ∼300 μg and ∼ 600 μg of CLF administered on every alternate day over 30 days significantly reduced the number of bacteria in the lung. With an inhaled dose of ∼600 μg/mice, reduction of mycobacterial colony forming units (CFU) was achieved by ∼1.95 Log10CFU times compared to CLF administered via oral gavage (∼1.18 Log10CFU). Lung histology scoring showed improved pathogenesis and inflammation in infected animals after 30 days of inhalation dosing of CLF-NCLs. The levels of pro-inflammatory mediators, including cytokines, TNF-α & IL-6, and MMP-2 in bronchoalveolar lavage fluid (BAL-F) and lung tissue homogenates, were attenuated after inhalation treatment. These pre-clinical data suggest inhalable CLF-NCLs are well tolerated, show significant anti-TB activity and apparently able to tackle the challenge of paradoxical chronic lung inflammation in murine TB model.

Comparison of the effects of negative pressure wound therapy and negative pressure wound therapy with instillation on wound healing in a porcine model.

Negative pressure wound therapy with instillation (NPWTi) is a novel method based on standard negative pressure wound therapy (NPWT). This study aimed to compare the effects of standard NPWT and NPWTi on bioburden and wound healing in a Staphylococcus aureus (S.aureus) infected porcine model. Green fluorescent protein-labeled S.aureus infected wounds were created on the back of porcine. Wounds were treated with NPWT or NPWT with instillation (saline). The tissue specimens were harvested on days 0 (12 h after bacterial inoculation), 2, 4, 6, and 8 at the center of wound beds. Viable bacterial counts, laser scanning confocal microscopy, PCR, western blot, and histological analysis were performed to assess virulence and wound healing. The bacterial count in the NPWTi group was lower than that of the NPWT group and the difference was statistically significant on day 2, day 4, day 6, and day 8 (P < 0.05). The expression levels of agrA, Eap, Spa, and Hla genes of the NPWTi group were significantly lower than that of the NPWT group on day 8 (P < 0.05). The bacterial invasion depth of the NPWTi group was significantly lower than that of the NPWT group on day 2, day 4, day 6, and day 8 (P < 0.05). Though the NPWTi group showed a significantly increased expression of bFGF and VEGF than that of the NPWT group in the early time (P < 0.05), NPWTi cannot lead to better histologic parameters than the NPWT group (P > 0.05). Our results demonstrated that NPWTi induced a better decrease in bacterial burden and virulence compared with standard NPWT. These advantages did not result in better histologic parameters on the porcine wound model.

Is Instillational Topical Negative Pressure Wound Therapy in Peri-Prosthetic Infections of the Breast Effective? A Pilot Study.

Peri-prosthetic breast infections pose a risk of severe complications after breast implant surgery. The need to remove the breast implant, control the infection and perform additional surgical procedures are the consequences. Reimplantation of an alloplastic implant is only appropriate after an infection-free interval. In this retrospective cohort study, we investigated the effectiveness of negative pressure wound treatment with instillation and dwell time (NPWTi-d) on peri-prosthetic breast infections in combination with implant removal and antibiotic therapy. Twelve patients treated with NPWTi-d due to breast implant infection were included in the study. The bacterial burden was analyzed using wound swabs before and after NPWTi-d. Additionally, laboratory values were determined before NPWTi-d and immediately before wound closure. A total of 13 peri-prosthetic breast infections in 12 patients were treated using implant removal and NPWTi-d. In 76.9% (n = 10) of the cases, the patients had undergone alloplastic breast reconstruction following cancer-related mastectomy, whereas 23.1% (n = 3) of the patients had undergone breast augmentation for cosmetic reasons. The bacterial burden in the breast pocket decreased statistically significant after implant removal and NPWTi-d. No shift from Gram-positive to Gram-negative bacteria was observed. Inflammatory markers rapidly decreased following treatment. NPWTi-d had a positive impact on the healing process after peri-prosthetic breast infections, leading to a decrease in bacterial burden within the wounds and contributing to uneventful healing. Therefore, secondary reimplantation of breast prostheses might be positively influenced when compared to conventional implant removal and simple secondary closure. Further studies are required to conclusively establish the beneficial long-term effects of using NPWTi-d for the treatment of peri-prosthetic breast infections.

Effect of SARs-CoV-2 pandemic on infection prevention behaviors and bacterial burden of high touch surfaces in a medical/surgical setting

This study aimed to determine the longitudinal efficacy of ultraviolet germicidal disinfection (UV-C) in a non-terminal disinfection context. Moreover, factors influencing enhanced infection prevention behaviors during the SARS-CoV-2 pandemic were evaluated. Sixty nursing staff from three medical/surgical wards in a large military hospital were recruited for a survey and microbiological sampling of high-touch surfaces (stethoscope, personal electronic device, common access card, and hospital ID badge) and portable medical equipment (wheelchairs and mobile commodes). Surveys included hand hygiene estimates, frequency/method of cleaning items of interest, perception of UV-C, and factors influencing the use of enhanced disinfection tools. Surveys and microbiological samples were performed prior to and after the installation of a rapid, automated ultraviolet disinfection enclosure for staff use. Both time points preceded the SARS-CoV-2 pandemic in the United States. A final survey/sampling time point was carried out eight months after the declaration of the COVID-19 pandemic. Participants’ hand hygiene frequency did not increase throughout the study, with > 80% reporting a minimum of 4 hand hygiene events per patient hour. The cleaning frequency of high-touch surfaces (non-clinical) but not portable medical equipment increased after installation of a UV-C disinfection tool and was sustained eight months into the COVID-19 pandemic. While a modest decrease in bacterial burden was observed after UV-C intervention, a more significant reduction was observed across all surfaces during pandemic time sampling, though no detectable decrease in pathogenic contamination was observed at either time point. Motivators of UV-C use included fear of SARS-CoV-2 contamination and transmission, ease of device use, and access to rapid, automated disinfection tools while deterrents reported included technical concerns, lack of time, and preference for other disinfection methods. Automated, rapid-cycle UV-C disinfection can be efficacious for high-touch surfaces not currently governed by infection prevention and control guidelines. The introduction of enhanced disinfection tools like UV-C can enhance the overall cleaning frequency and is correlated with mild decreases in bacterial burden of high-touch surfaces, this is enhanced during periods of heightened infection threat. Evidence from this study offers insights into the factors which prompt healthcare workers to internalize/dismiss enhanced infection prevention procedures.

Inhibition of Granuloma Triglyceride Synthesis Imparts Control of Mycobacterium tuberculosis Through Curtailed Inflammatory Responses.

Lipid metabolism plays a complex and dynamic role in host-pathogen interaction during Mycobacterium tuberculosis infection. While bacterial lipid metabolism is key to the success of the pathogen, the host also offers a lipid rich environment in the form of necrotic caseous granulomas, making this association beneficial for the pathogen. Accumulation of the neutral lipid triglyceride, as lipid droplets within the cellular cuff of necrotic granulomas, is a peculiar feature of pulmonary tuberculosis. The role of triglyceride synthesis in the TB granuloma and its impact on the disease outcome has not been studied in detail. Here, we identified diacylglycerol O-acyltransferase 1 (DGAT1) to be essential for accumulation of triglyceride in necrotic TB granulomas using the C3HeB/FeJ murine model of infection. Treatment of infected mice with a pharmacological inhibitor of DGAT1 (T863) led to reduction in granuloma triglyceride levels and bacterial burden. A decrease in bacterial burden was associated with reduced neutrophil infiltration and degranulation, and a reduction in several pro-inflammatory cytokines including IL1β, TNFα, IL6, and IFNβ. Triglyceride lowering impacted eicosanoid production through both metabolic re-routing and via transcriptional control. Our data suggests that manipulation of lipid droplet homeostasis may offer a means for host directed therapy in Tuberculosis.

Replication Dynamics for Six Gram-Negative Bacterial Species during Bloodstream Infection.

ABSTRACTBloodstream infections (BSI) are a major public health burden due to high mortality rates and the cost of treatment. The impact of BSI is further compounded by a rise in antibiotic resistance among Gram-negative species associated with these infections. Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, Enterobacter hormaechei, Citrobacter freundii, and Acinetobacter baumannii are all common causes of BSI, which can be recapitulated in a murine model. The objective of this study was to characterize infection kinetics and bacterial replication rates during bacteremia for these six pathogens to gain a better understanding of bacterial physiology during infection. Temporal observations of bacterial burdens of the tested species demonstrated varied abilities to establish colonization in the spleen, liver, or kidney. K. pneumoniae and S. marcescens expanded rapidly in the liver and kidney, respectively. Other organisms, such as C. freundii and E. hormaechei, were steadily cleared from all three target organs throughout the infection. In situ replication rates measured by whole-genome sequencing of bacterial DNA recovered from murine spleens demonstrated that each species was capable of sustained replication at 24 h postinfection, and several species demonstrated <60-min generation times. The relatively short generation times observed in the spleen were in contrast to an overall decrease in bacterial burden for some species, suggesting that the rate of immune-mediated clearance exceeded replication. Furthermore, bacterial generation times measured in the murine spleen approximated those measured during growth in human serum cultures. Together, these findings provide insight into the infection kinetics of six medically important species during bacteremia.

Selective Activation of MST1/2 Kinases by Retinoid Agonist Adapalene Abrogates AURKA-Regulated Septic Arthritis.

Septic arthritis is a chronic inflammatory disorder caused by Staphylococcus aureus invasion of host synovium, which often progresses to impairment of joint functions. Although it is known that disease progression is intricately dependent on dysregulated inflammation of the knee joint, identification of molecular events mediating such imbalance during S. aureus-induced septic arthritis still requires detailed investigation. In this article, we report that Aurora kinase A (AURKA) responsive WNT signaling activates S. aureus infection-triggered septic arthritis, which results in inflammation of the synovium. In this context, treatment with adapalene, a synthetic retinoid derivative, in a mouse model for septic arthritis shows significant reduction of proinflammatory mediators with a simultaneous decrease in bacterial burden and prevents cartilage loss. Mechanistically, adapalene treatment inhibits WNT signaling with concomitant activation of HIPPO signaling, generating alternatively activated macrophages. Collectively, we establish adapalene as a promising strategy to suppress S. aureus-induced irreversible joint damage.

A listeriolysin O subunit vaccine is protective against Listeria monocytogenes

Listeria monocytogenes is a facultative intracellular pathogen responsible for the life-threatening disease listeriosis. The pore-forming toxin listeriolysin O (LLO) is a critical virulence factor that plays a major role in the L. monocytogenes intracellular lifecycle and is indispensable for pathogenesis. LLO is also a dominant antigen for T cells involved in sterilizing immunity and it was proposed that LLO acts as a T cell adjuvant. In this work, we generated a novel full-length LLO toxoid (LLOT) in which the cholesterol-recognition motif, a threonine-leucine pair located at the tip of the LLO C-terminal domain, was substituted with two glycine residues. We showed that LLOT lost its ability to bind cholesterol and to form pores. Importantly, LLOT retained binding to the surface of epithelial cells and macrophages, suggesting that it could efficiently be captured by antigen-presenting cells. We then determined if LLOT can be used as an antigen and adjuvant to protect mice from L. monocytogenes infection. Mice were immunized with LLOT alone or together with cholera toxin or Alum as adjuvants. We found that mice immunized with LLOT alone or in combination with the Th2-inducing adjuvant Alum were not protected against L. monocytogenes. On the other hand, mice immunized with LLOT along with the experimental adjuvant cholera toxin, were protected against L. monocytogenes, as evidenced by a significant decrease in bacterial burden in the liver and spleen three days post-infection. This immunization regimen elicited mixed Th1, Th2, and Th17 responses, as well as the generation of LLO-neutralizing antibodies. Further, we identified T cells as being required for immunization-induced reductions in bacterial burden, whereas B cells were dispensable in our model of non-pregnant young mice. Overall, this work establishes that LLOT is a promising vaccine antigen for the induction of protective immunity against L. monocytogenes by subunit vaccines containing Th1-driving adjuvants.

Migratory memory CD4 T cells surveilling the lower reproductive tract direct rapid clearance of Chlamydia muridarum following vaginal challenge

Abstract Despite their importance for immunity against sexually transmitted infections, the regulation and function of CD4 T cells in the female reproductive tract (FRT) remains poorly defined. Here we show that across human, non-human primate, and mouse species the FRT memory CD4 T cell pool consists of distinct subsets corresponding to migratory (TMM) and resident (TRM) memory T cells. TMM in the FRT exhibit broad expression of trafficking molecules, restricted distribution to discreet areas of the FRT, and differential responses to local infection. To investigate the contribution of TMM to protective immunity in the FRT, we constructed an influenza virus (HK/x-31) expressing an immunodominant CD4 T cell epitope from the Chlamydia muridarum probable outer membrane protein (PmpG-1303–311). C57Bl/6 mice were infected intranasally with x31-PmpG1 to generate PmpG1-specific CD4 TMM and investigate their ability to surveil distant mucosal tissues. PmpG1-specific CD4 T cells were found restricted into the lower, but not upper, FRT and expressed chemokine receptors and adhesion molecules consistent with TMM. Vaginal challenge of x31-PmpG1 memory mice with C. muridarum showed a significant decrease in bacterial burden at 14 days post-infection (dpi), when bacterial clearance was first detectable in naïve control mice. Notably, x31-PmpG1 memory mice treated with FTY720 during the initial stages of C. muridarum challenge failed to limit bacterial growth, suggesting this effect was due in part to TMM localization to the FRT. These data show that vaccinating at distant mucosal sites can generate surveilling CD4 TMM cells that are distinct from classical central, effector and resident memory CD4 T cells, and can protect against pathogens in the FRT.

Abstract 2: Heat Generating Nanocomposite To Reduce Infection

Purpose: To evaluate the combination of mild hyperthermia plus antibiotics for reducing Stapylococcus aureus biofilms associated with silicone materials. Methods: The additive effect of non-ablative hyperthermia with antibiotics was explored in a mouse model. Small disks of silicone with [4,4-bis(2-ethylhexyl)cyclopenta[2,1-b;3,4-b’]dithiophene-2,6-diyl-alt-2,1,3-benzoselenadiazole-4,7-diyl] (PCPDTBSe) nanoparticles were inoculated with Xen29 S. aureus biofilms. These disks were implanted in the flanks of hairless, immunocompetent Crl:SKH1-hrBR mice, with each mouse receiving with 1 silicone disk on the left flank and 1 nanocomposite disk on the right flank. After 24 hours, the mice were imaged using IVIS to evaluate the infection using the bioluminescent signature from the Xen 29. Mice were treated with either 200µL 2mg/mL Gentamicin orIP Saline, with or without laser (3W, CW, 800nm, 25s) applied directly over the flank 1 hour afterinjection. Mice were imaged using IVIS 24 hours after treatment. The disks and surrounding infected tissue were extracted and homogenized. The homogenate was diluted and plated in triplicate to calculate the CFU /g per disk. The change in IVIS luminescence before and after treatment was compared. A total of 14 mice were implanted and treated. 2 mice received treatment of IP Gentamicin only, 4 mice received IP saline and laser therapy, and 8 mice received IP Gentamicin and laser therapy. Results: Only mice treated with Gentamicin and laser therapy demonstrated a decrease in luminescence on IVIS after treatment, representing a decrease in bacterial burden. These mice also demonstrated the greatest percent decrease (-65.8%) of CFU/g on the nanocomposite disk relative to the silicone disk. This was also the only treatment group which saw a significant decrease in bacterial burden on the nanocomposite disk relative to the silicone disk. Conclusion: Mice treated with the combined Gentamicin and laser therapy had the largest percent reduction in biofilm burden on the BSe-Si disk relative to the Si disk. This supports the hypothesis that joint heat and antibiotic therapy can be effective at reducing biofilms in vivo. Ultimately, this technology may have clinical utility towards treating biofilms on indwelling medical devices, mitigating a major burden of disease.

Abstract 110: Testing The Effect Of A Novel Hydrogen Sulfide Releasing Peptide On Infected Burn Wounds

Purpose: To evaluate the antimicrobial effects of an H2S releasing dipeptide on Staphylococcus aureus. Methods: An H2S releasing peptide hydrogel (S-FE) was synthesized and characterized by standard methodology prior to beginning studies with S. aureus. A control peptide that does not release H2S (C-FE) was also developed. The gels were evaluated against two variants of S. aureus, Xen29, which is bioluminescent and UAMS-1, which is known to form robust biofilms. Cysteine was used as the trigger for release of the H2S from the S-FE. Thus, the first experiment evaluated the effect of increasing concentrations of cysteine on the growth of S. aureus. Secondly, the effect the peptide gels on planktonic S. aureus was evaluated with using optical absorption of the culture, complemented by serial dilution and enumeration of the colony forming units (CFUs). The gels were then evaluated against developing or established biofilms to evaluate the potential for the H2S gels to be bacteriocidal or bacteriostatic. Biofilm mass was quantified using crystal violet assay, and bacterial viability was determined by in vivo imaging and CFU enumeration. An ex vivo porcine skin model was then used to evaluate the potential for the peptide gels to disrupt S. aureus biofilms in burns, and this was then translated into an in vivo porcine burn model to evaluate the safety of the peptides gels and reduction of bacterial burden compared to silver sulfadiazine. The impact of H2S on blood perfusion and wound healing were evaluated using laser Doppler scanning of the burns and histopathological imaging. Results: Both the S-FE and C-FE peptide hydrogels exhibited reduction in S. aureus in planktonic or biofilm form, Indicating an antimicrobial effect of the peptide itself. H2S-releasing S-FE gel which had a better antimicrobial effect in general, suggesting the inhibitory effects of H2S gas. The S-FE and C-FE dipeptide gels suppressed the bacterial ability to grow biofilm. Moreover, the S-FE had a significant antimicrobial effect on an established biofilm compared to C-Fe and a bacterial only group which could indicate the gas ability to infiltrate the biofilm to impact the bacteria directly. The impact of the gels in infected ex vivo porcine skin shows a significant decrease in bacterial burden determined by reductions in both CFUs and photon count emitted from the bioluminescent bacteria. An antimicrobial effect was noticed with the S-FE group compared to the other groups as the infection was cleared before day 14 compared to its control which persisted to day 21. There was no clear acceleration of wound healing with any of the treatments. There were no negative impacts of the dipeptide hydrogels on the health of the animals. Conclusion: The S-FE and C-FE inhibited bacterial growth, thereby limiting biofilm formation or disrupting established biofilms, and S-FE showed better effects than C-FE. These antimicrobial H2S-releasing dipeptide hydrogels provide a promising new approach to treat wound infections.

IL-17 Promotes Pseudomonas aeruginosa Keratitis in C57BL/6 Mouse Corneas.

The aim of this study was to elucidate the expression and functions of IL-17 in C57BL/6 mouse corneas in response to Pseudomonas aeruginosa infection. We found that P. aeruginosa infection induced and increased signaling of IL-23/23R/17/17R in mouse corneas. Targeting IL-17A or the IL-17A-specific receptor IL-17RA/IL-17RC with neutralizing Abs resulted in a significant decrease in the severity of P. aeruginosa keratitis, including a decrease in bacterial burden and polymorphonuclear leukocyte infiltration. IL-17A-signaling blockade also significantly reduced the expression of the proinflammatory cytokines L-1β, IL-24, and MMP-13 and increased the expression of the anti-inflammatory cytokine IL-1RA in mouse corneal epithelium. The presence of mouse IL-17A exacerbated P. aeruginosa-mediated tissue destruction. A cytokine protein array revealed that the expression of osteoprotegerin (OPG) was regulated by IL-17A, and OPG neutralization also resulted in a decrease in the severity of P. aeruginosa keratitis. Although both IL-17 and OPG affected the balanced expression of IL-1β and IL-1RA, only IL-17 inhibited the expression of TH2 cytokines. Taken together, our results revealed that IL-17A, along with its downstream factor OPG, plays a detrimental role in the pathogenesis of P. aeruginosa keratitis. Targeting IL-17A and/or the OPG/RANKL/RANK/TRAIL system is a potential therapeutic strategy in controlling the outcome of P. aeruginosa keratitis, which was demonstrated by concurrent topical application of IL-17A-neutralizing Ab and ciprofloxacin in B6 mice.

Antibodies against the DNABII protein integration host factor (IHF) inhibit sinus implant biofilms.

Chronic rhinosinusitis is a common, costly condition often treated with endoscopic sinus surgery and intraoperative placement of intranasal sinus implant materials. Whereas these materials aid in postoperative healing, they also support bacterial biofilm formation and thus contribute to negative outcomes. This study examined pretreatment of sinus implant materials with antibody against an essential bacterial biofilm structural component, the DNABII family of DNA-binding proteins, as a strategy to prevent biofilm formation. Sinus implant materials were equilibrated in immunoglobulin G (IgG)-enriched antiserum against the DNABII protein integration host factor (IHF), individually or in combination with amoxicillin-clavulanate prior to inoculation with nontypeable Haemophilus influenzae (NTHI), a predominant pathogen of chronic rhinosinusitis. After 16 hours, the bacterial burden was quantitated and compared to pretreatment with saline, IgG-enriched naive serum, or amoxicillin-clavulanate alone. NTHI readily formed biofilms on all three materials in vitro. However, pretreatment of each material with IgG-enriched anti-IHF resulted in a significant decrease in bacterial burden compared to controls (P ≤ 0.05). Moreover, a significant and synergistic outcome was achieved with a cocktail of anti-IHF plus amoxicillin-clavulanate (P ≤ 0.05) with complete inhibition of NTHI biofilm formation on all three materials. Biofilm formation was well supported in vitro on three sinus implant materials that vary in composition and resorption characteristics; however, pretreatment of each with DNABII protein targeted antibodies in combination with a previously ineffective antibiotic was highly effective to prevent the formation NTHI biofilms. These data demonstrate the potential for clinical utility of pretreatment of sinus implant and additional surgical materials with anti-DNABII antibodies. NA Laryngoscope, 130:1364-1371, 2020.

Atopobium and Fusobacterium as novel candidates for sarcoidosis-associated microbiota.

Sarcoidosis is a granulomatous disease that mainly affects the lung. A role of microbial factors in disease pathogenesis is assumed, but has not been investigated systematically in a large cohort.This cross-sectional study compared the lung microbiota of 71 patients with sarcoidosis, 15 patients with idiopathic pulmonary fibrosis (non-infectious controls) and 10 healthy controls (HCs). Next-generation sequencing of 16S DNA was used on bronchoalveolar lavage samples to characterise the microbial composition, which was analysed for diversity and indicator species. Host genotypes for 13 known sarcoidosis risk variants were determined and correlated with microbial parameters.The microbial composition differed significantly between sarcoidosis and HC samples (redundancy analysis ANOVA, p=0.025) and between radiographic Scadding types. Atopobium spp. was detected in 68% of sarcoidosis samples, but not in HC samples. Fusobacterium spp. was significantly more abundant in sarcoidosis samples compared with those from HCs. Mycobacteria were found in two of 71 sarcoidosis samples. Host-genotype analysis revealed an association of the rs2076530 (BTNL2) risk allele with a decrease in bacterial burden (p=0.002).Our results indicate Scadding type-dependent microbiota in sarcoidosis BAL samples. Atopobium spp. and Fusobacterium spp. were identified as sarcoidosis-associated bacteria, which may enable new insights into the pathogenesis and treatment of the disease.

Efficacy of Telavancin Alone and in Combination with Ampicillin in a Rat Model of Enterococcus faecalis Endocarditis.

We first assessed telavancin (TLV) pharmacokinetics in rats after a single subcutaneous dose of 35 mg/kg of body weight. The pharmacokinetic data were used to predict a TLV dose that simulates human exposure, and the efficacy of TLV was then evaluated using a TLV dose of 21 mg/kg every 12 h against Enterococcus faecalis OG1RF (TLV MIC of 0.06 μg/ml) in a rat endocarditis model with an indwelling catheter. Therapy was given for 3 days with TLV, daptomycin (DAP), or ampicillin (AMP) monotherapy and with combinations of TLV plus AMP, AMP plus gentamicin (GEN), and AMP plus ceftriaxone (CRO); rats were sacrificed 24 h after the last dose. Antibiotics were given to simulate clinically relevant concentrations or as used in other studies. TLV treatment resulted in a significant decrease in bacterial burden (CFU per gram) in vegetations from 6.0 log10 at time 0 to 3.1 log10 after 3 days of therapy. Bacterial burdens in vegetations were also significantly lower in the TLV-treated rats than in the AMP (P = 0.0009)- and AMP-plus-GEN (P = 0.035)-treated rats but were not significantly different from that of the AMP-plus-CRO-treated rats. Bacterial burdens from vegetations in TLV monotherapy and TLV-plus-AMP-and-DAP groups were similar to each other (P ≥ 0.05). Our data suggest that further study of TLV as a therapeutic alternative for deep-seated infections caused by vancomycin-susceptible E. faecalis is warranted.

LB-S&T-35 SIDEROPHORE VACCINE CONJUGATES PROTECT AGAINST UROPATHOGENIC ESCHERICHIA COLI IN A MURINE MODEL OF URINARY TRACT INFECTION

You have accessJournal of UrologyLate-Breaking S&T Poster1 Apr 2016LB-S&T-35 SIDEROPHORE VACCINE CONJUGATES PROTECT AGAINST UROPATHOGENIC ESCHERICHIA COLI IN A MURINE MODEL OF URINARY TRACT INFECTION Laura Mike, Sara Smith, Christopher Sumner, and Harry Mobley Laura MikeLaura Mike More articles by this author , Sara SmithSara Smith More articles by this author , Christopher SumnerChristopher Sumner More articles by this author , and Harry MobleyHarry Mobley More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.03.116AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Uropathogenic Escherichia coli (UPEC) is the primary etiological agent of uncomplicated urinary tract infections (UTIs). Over half of all women will experience a UTI in their lifetime and one in forty women suffers recurrent UTIs. The repeated administration of antibiotics to treat recurrent UTIs has resulted in a steady increase in antibiotic resistance among UPEC isolates. The objective of this study was to identify novel vaccine strategies for the prevention of UTIs. Bacteria-derived siderophores, which are secreted small molecules used for iron acquisition, were targeted for use in our UTI vaccine. Specifically, the two siderophores aerobactin (Aebt) and yersiniabactin (Ybt) were selected due to their proven role in bacterial virulence, their association with pathogenic E. coli strains, their surface exposed nature, and the protection their cognate outer membrane protein receptors provide against experimental UTI. METHODS Aebt and Ybt were conjugated to immunogenic cationized bovine serum albumin (cBSA). Mice were intranasally vaccinated with cBSA, cBSA conjugated to Aebt (cBSA-Aebt), cBSA conjugated to Ybt (cBSA-Ybt), or a mixture of the two antigen conjugates. After the initial vaccination, mice were boosted once a week for two weeks. Mice were then intraurethrally challenged with UPEC. Bacterial burdens in the urine, bladder, and kidneys were quantified after 48 hours of infection. RESULTS Vaccination with cBSA-Aebt, cBSA-Ybt, or the 1:1 mixture of the two cBSA-conjugates resulted in a ten-fold decrease in bacterial burdens in the urine compared to mice vaccinated with cBSA alone. Mice vaccinated with cBSA-Ybt had a ten-fold decrease in bacterial burden in the kidneys. Combining the two vaccine conjugates resulted in a 100-fold decrease in bacterial burden in the kidneys. Further studies revealed that vaccination with these cBSA-siderophore conjugates stimulates an adaptive immune response that recognizes the bacterial siderophores. CONCLUSIONS The data presented here identify the potential use of bacterial siderophores in a UTI vaccine. This is the first evidence that bacteria-specific small molecules can be formulated into a protective vaccine and represent untapped resources as antigens in other bacterial diseases. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e351 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Laura Mike More articles by this author Sara Smith More articles by this author Christopher Sumner More articles by this author Harry Mobley More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Comparison of the early host immune response to two widely diverse virulent strains of Burkholderia pseudomallei that cause acute or chronic infections in BALB/c mice

Burkholderia pseudomallei is the etiologic agent of melioidosis, which is endemic in Southeast Asia and Northern Australia. We previously found by the intraperitoneal (IP) route that we could discern differences in virulence in mice amongst different strains of B. pseudomallei. We report an early immune response study comparing two strains in our collection which represent the least, B. pseudomallei 1106a, and one of the most, HBPUB10134a, virulent strains in BALB/c mice. B. pseudomallei HBPUB10134a infected mouse spleens contained a 2–3 log higher bacterial burden than mice infected with B. pseudomallei 1106a 3 days post-infection (PI). More and higher amounts of inflammatory cytokines/chemokines were detected in sera and spleen extracts from B. pseudomallei HBPUB10134a than B. pseudomallei 1106a infected mice. The most prominent were IFNγ, IL-1α, IL-1β, IL-6, IL-10, IP-10, and MIG. After 7 days PI, there was a decrease in bacterial burden in spleens from 1106a infected mice and a decrease in cytokines/chemokines in sera and spleen extracts from both sets of mice. By day 14 PI we saw an increase in monocytes/macrophages, NK cells, and granulocytes in spleens from both sets of mice. No B. pseudomallei HBPUB10134a infected mice survived after this time. In summary, B. pseudomallei HBPUB10134a was more virulent and induced host innate immune responses typical of a more acute-type infection than did B. pseudomallei 1106a which produced a more chronic infection in mice.

Zinc Chelation by a Small-Molecule Adjuvant Potentiates Meropenem Activity in Vivo against NDM-1-Producing Klebsiella pneumoniae.

The widespread emergence of antibiotic drug resistance has resulted in a worldwide healthcare crisis. In particular, the extensive use of β-lactams, a highly effective class of antibiotics, has been a driver for pervasive β-lactam resistance. Among the most important resistance determinants are the metallo-β-lactamases (MBL), which are zinc-requiring enzymes that inactivate nearly all classes of β-lactams, including the last-resort carbapenem antibiotics. The urgent need for new compounds targeting MBL resistance mechanisms has been widely acknowledged; however, the development of certain types of compounds-namely metal chelators-is actively avoided due to host toxicity concerns. The work herein reports the identification of a series of zinc-selective spiro-indoline-thiadiazole analogues that, in vitro, potentiate β-lactam antibiotics against an MBL-carrying pathogen by withholding zinc availability. This study demonstrates the ability of one such analogue to inhibit NDM-1 in vitro and, using a mouse model of infection, shows that combination treatment of the respective analogue with meropenem results in a significant decrease in bacterial burden in contrast to animals that received antibiotic treatment alone. These results support the therapeutic potential of these chelators in overcoming antibiotic resistance.