Anatomical Characteristics Contributing to Patellar Dislocations Following MPFL Reconstruction: A Dynamic Simulation Study.

Pathologic anatomy is a primary factor contributing to redislocation of the patella following reconstruction of the medial patellofemoral ligament (MPFL). A pivot landing was simulated following MPFL reconstruction, with the hypothesis that position of the tibial tuberosity, depth of the trochlear groove, and height of the patella are correlated with lateral patellar maltracking. Thirteen dynamic simulation models represented subjects being treated for recurrent patellar instability. Simplified Hertzian contact governed patellofemoral and tibiofemoral joint reaction forces. Pivot landing was represented with and without an MPFL graft in place. Measurements related to patellar height (Caton-Deschamps index), trochlear groove depth (lateral trochlear inclination), and position of the tibial tuberosity (lateral tibial tuberosity to posterior cruciate attachment distance, or lateral TT-PCL distance) were measured from the models and correlated with patellar lateral shift with the knee extended (5 deg of flexion) and flexed (40 deg). The patella dislocated for all models without an MPFL graft and for two models with a graft represented. With an MPFL graft represented, patellar lateral shift was correlated with Caton-Deschamps index (r2 > 0.35, p < 0.03) and lateral trochlear inclination (r2 ≥ 0.45, p < 0.02) at both 5 deg and 40 deg of flexion. For a simulated pivot landing with an MPFL graft in place, lateral patellar tracking was associated with a high patella (alta) and shallow trochlear groove. The study emphasizes the importance of simulating activities that place the patella at risk of dislocation when evaluating patellar stability.

Comparative macrolide use in humans and animals: should macrolides be moved off the World Health Organisation's critically important antimicrobial list?

Macrolide antibiotics are categorized by the WHO as Highest Priority, Critically Important Antimicrobials due to their recommendation as treatment for severe cases of campylobacteriosis in humans; a self-limiting, rarely life-threatening, zoonotic foodborne infection. Low rates of macrolide resistance in Campylobacter jejuni and the availability of alternative treatments have prompted some regulatory schemes to assign macrolides to a lower importance category. Apart from rare, specific infections, macrolides largely play a supportive role to other drug classes in human medicine. By contrast, although the advent of alternative control methods has seen significant reductions in macrolide use in intensive livestock, they still have a crucial role in the treatment/control of respiratory infections and liver abscesses in cattle. Whilst acknowledging that ongoing surveillance is required to reduce the spread of recently emerged, transferable macrolide resistance among Campylobacter, this article recommends that macrolides should be moved to the WHO Highly Important category.

Current and future perspectives on the categorization of antimicrobials used in veterinary medicine.

The emergence of antimicrobial resistance in human and veterinary bacterial pathogens has led to concerns regarding the use of antimicrobials in veterinary medicine. Consequently, regulatory agencies have developed procedures for assessing the risk associated with the use of a specific antimicrobial as part of the drug approval process. Due consideration for the importance (priority categorization) of the antimicrobial to human medicine is part of this risk assessment process. Additionally, nongovernmental organizations have developed antimicrobial categorization schemes to protect the use and effectiveness of these medicines. However, the goals and methods of the various categorization schemes vary, resulting in final categorizations that are different. Although harmonizing these schemes would bring clarity to antimicrobial resistance discussions and policy, it has the disadvantage of not accounting for regional antimicrobial resistance and use, potentially removing effective medicines from clinical use in situations where they are wholly appropriate. Antimicrobials should be classified in a One Health manner, where both physician and veterinarian share the responsibility for antimicrobial use. The purpose of this article is to summarize current antimicrobial categorization schemes using illustrative examples to highlight differences and provide perspectives on the impact of the current schemes and future directions.

Plasmid-located extended-spectrum ß-lactamase gene blaROB-2 in Mannheimia haemolytica.

OBJECTIVES: To identify and analyse the first ESBL gene from Mannheimia haemolytica. METHODS: Susceptibility testing was performed according to CLSI. Plasmids were extracted via alkaline lysis and transferred by electrotransformation. The sequence was determined by WGS and confirmed by Sanger sequencing. RESULTS: The M. haemolytica strain 48 showed high cephalosporin MICs. A single plasmid, designated pKKM48, with a size of 4323 bp, was isolated. Plasmid pKKM48 harboured a novel blaROB gene, tentatively designated blaROB-2, and was transferred to Pasteurella multocida B130 and to Escherichia coli JM107. PCR assays and susceptibility testing confirmed the presence and activity of the blaROB-2 gene in the P. multocida and in the E. coli recipient carrying plasmid pKKM48. The transformants had high MICs of all ß-lactam antibiotics. An ESBL phenotype was seen in the E. coli transformant when applying the CLSI double-disc confirmatory test for E. coli. The blaROB-2 gene from plasmid pKKM48 differed in three positions from blaROB-1, resulting in two amino acid exchanges and one additional amino acid in the deduced ß-lactamase protein. In addition to blaROB-2, pKKM48 harboured mob genes and showed high similarity to other plasmids from Pasteurellaceae. CONCLUSIONS: This study described the first ESBL gene in Pasteurellaceae, which may limit the therapeutic options for veterinarians. The transferability to Enterobacteriaceae with the functional activity of the gene in the new host underlines the possibility of the spread of this gene across species or genus boundaries.

Applying definitions for multidrug resistance, extensive drug resistance and pandrug resistance to clinically significant livestock and companion animal bacterial pathogens.

Standardized definitions for MDR are currently not available in veterinary medicine despite numerous reports indicating that antimicrobial resistance may be increasing among clinically significant bacteria in livestock and companion animals. As such, assessments of MDR presented in veterinary scientific reports are inconsistent. Herein, we apply previously standardized definitions for MDR, XDR and pandrug resistance (PDR) used in human medicine to animal pathogens and veterinary antimicrobial agents in which MDR is defined as an isolate that is not susceptible to at least one agent in at least three antimicrobial classes, XDR is defined as an isolate that is not susceptible to at least one agent in all but one or two available classes and PDR is defined as an isolate that is not susceptible to all agents in all available classes. These definitions may be applied to antimicrobial agents used to treat bovine respiratory disease (BRD) caused by Mannheimia haemolytica, Pasteurella multocida and Histophilus somni and swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, P. multocida and Streptococcus suis, as well as antimicrobial agents used to treat canine skin and soft tissue infections (SSTIs) caused by Staphylococcus and Streptococcus species. Application of these definitions in veterinary medicine should be considered static, whereas the classification of a particular resistance phenotype as MDR, XDR or PDR could change over time as more veterinary-specific clinical breakpoints or antimicrobial classes and/or agents become available in the future.

Review on Abyssomicins: Inhibitors of the Chorismate Pathway and Folate Biosynthesis.

Antifolates targeting folate biosynthesis within the shikimate-chorismate-folate metabolic pathway are ideal and selective antimicrobials, since higher eukaryotes lack this pathway and rely on an exogenous source of folate. Resistance to the available antifolates, inhibiting the folate pathway, underlines the need for novel antibiotic scaffolds and molecular targets. While para-aminobenzoic acid synthesis within the chorismate pathway constitutes a novel molecular target for antifolates, abyssomicins are its first known natural inhibitors. This review describes the abyssomicin family, a novel spirotetronate polyketide Class I antimicrobial. It summarizes synthetic and biological studies, structural, biosynthetic, and biological properties of the abyssomicin family members. This paper aims to explain their molecular target, mechanism of action, structure⁻activity relationship, and to explore their biological and pharmacological potential. Thirty-two natural abyssomicins and numerous synthetic analogues have been reported. The biological activity of abyssomicins includes their antimicrobial activity against Gram-positive bacteria and mycobacteria, antitumor properties, latent human immunodeficiency virus (HIV) reactivator, anti-HIV and HIV replication inducer properties. Their antimalarial properties have not been explored yet. Future analoging programs using the structure⁻activity relationship data and synthetic approaches may provide a novel abyssomicin structure that is active and devoid of cytotoxicity. Abyssomicin J and atrop-o-benzyl-desmethylabyssomicin C constitute promising candidates for such programs.

In Vitro ADME Properties of Two Novel Antimicrobial Peptoid-Based Compounds as Potential Agents against Canine Pyoderma.

Antimicrobial peptides (AMPs) hold promise as the next generation of antimicrobial agents, but often suffer from rapid degradation in vivo. Modifying AMPs with non-proteinogenic residues such as peptoids (oligomers of N-alkylglycines) provides the potential to improve stability. We have identified two novel peptoid-based compounds, B1 and D2, which are effective against the canine skin pathogen Staphylococcus pseudintermedius, the main cause of antibiotic use in companion animals. We report on their potential to treat infections topically by characterizing their release from formulation and in vitro ADME properties. In vitro ADME assays included skin penetration profiles, stability to proteases and liver microsomes, and plasma protein binding. Both B1 and D2 were resistant to proteases and >98% bound to plasma proteins. While half-lives in liver microsomes for both were >2 h, peptoid D2 showed higher stability to plasma proteases than the peptide-peptoid hybrid B1 (>2 versus 0.5 h). Both compounds were suitable for administration in an oil-in-water cream formulation (50% release in 8 h), and displayed no skin permeation, in the absence or presence of skin permeability modifiers. Our results indicate that these peptoid-based drugs may be suitable as antimicrobials for local treatment of canine superficial pyoderma and that they can overcome the inherent limitations of stability encountered in peptides.

Evaluation of Veterinary-Specific Interpretive Criteria for Susceptibility Testing of Streptococcus equi Subspecies with Trimethoprim-Sulfamethoxazole and Trimethoprim-Sulfadiazine.

Antimicrobial susceptibility test results for trimethoprim-sulfadiazine with Streptococcus equi subspecies are interpreted based on human data for trimethoprim-sulfamethoxazole. The veterinary-specific data generated in this study support a single breakpoint for testing trimethoprim-sulfamethoxazole and/or trimethoprim-sulfadiazine with S. equi This study indicates trimethoprim-sulfamethoxazole as an acceptable surrogate for trimethoprim-sulfadiazine with S. equi.

Analysis and comparative genomics of ICEMh1, a novel integrative and conjugative element (ICE) of Mannheimia haemolytica.

OBJECTIVES: The aim of this study was to identify and analyse the first integrative and conjugative element (ICE) from Mannheimia haemolytica, the major bacterial component of the bovine respiratory disease (BRD) complex. METHODS: The novel ICEMh1 was discovered in the whole-genome sequence of M. haemolytica 42548 by sequence analysis and comparative genomics. Transfer of ICEMh1 was confirmed by conjugation into Pasteurella multocida recipient cells. RESULTS: ICEMh1 has a size of 92,345 bp and harbours 107 genes. It integrates into a chromosomal tRNA(Leu) copy. Within two resistance gene regions of ∼ 7.4 and 3.3 kb, ICEMh1 harbours five genes, which confer resistance to streptomycin (strA and strB), kanamycin/neomycin (aphA1), tetracycline [tetR-tet(H)] and sulphonamides (sul2). ICEMh1 is related to the recently described ICEPmu1 and both ICEs seem to have evolved from a common ancestor. A region of ICEMh1 that is absent in ICEPmu1 was found in putative ICE regions of other M. haemolytica genomes, suggesting a recombination event between two ICEs. ICEMh1 transfers to P. multocida by conjugation, in which it also uses a tRNA(Leu) as the integration site. PCR assays and susceptibility testing confirmed the presence and activity of the ICEMh1-associated resistance genes in the P. multocida recipient. CONCLUSIONS: These findings showed that ICEs, with structurally variable resistance gene regions, are present in BRD-associated Pasteurellaceae, can easily spread across genus borders and enable the acquisition of multidrug resistance via a single horizontal gene transfer event. This poses a threat to efficient antimicrobial chemotherapy of BRD-associated bacterial pathogens.

Antibacterial activity of novel bacterial topoisomerase inhibitors against key veterinary pathogens.

Multidrug-resistant bacteria infect companion animals and livestock in addition to their devastating impact on human health. Novel Bacterial Topoisomerase Inhibitors (NBTIs) with excellent activity against Gram-positive bacteria have previously been identified as promising new antibacterial agents. Herein, we evaluate the antibacterial activity of these NBTIs against a variety of important veterinary pathogens and demonstrate outstanding in vitro activity, especially against staphylococci.

Effectiveness of Transitional Care Program among High-Risk Discharged Patients: A Quasi-Experimental Study on Saving Costs, Post-Discharge Readmissions and Emergency Department Visits.

Transitional care programs (TCPs), where hospital care team members repeatedly follow up with discharged patients, aim to reduce post-discharge hospital or emergency department (ED) utilization and healthcare costs. We examined the effectiveness of TCPs at reducing healthcare costs, hospital readmissions, and ED visits. Centers for Medicare and Medicaid Services Bundled Payments for Care Improvement (BPCI) program adjudicated claims files and electronic health records from Greenville Memorial Hospital, Greenville, SC, were accessed. Data on post-discharge 30- and 90-day ED visits and readmissions, total costs, and episodes with costs over BPCI target prices were extracted from November 2017 to July 2020 and compared between the "TCP-Graduates" (N = 85) and "Did Not Graduate" (DNG) (N = 1310) groups. As compared to the DNG group, the TCP-Graduates group had significantly fewer 30-day (7.1% vs. 14.9%, p = 0.046) and 90-day (15.5% vs. 26.3%, p = 0.025) readmissions, episodes with total costs over target prices (25.9% vs. 36.6%, p = 0.031), and lower total cost/episode (USD 22,439 vs. USD 28,633, p = 0.018), but differences in 30-day (9.4% vs. 11.2%, p = 0.607) and 90-day (20.0% vs. 21.9%, p = 0.680) ED visits were not significant. TCP was associated with reduced post-discharge hospital readmissions, total care costs, and episodes exceeding target prices. Further studies with rigorous designs and individual-level data should test these findings.

Standardized methods and quality control limits for agar and broth microdilution susceptibility testing of Mycoplasma pneumoniae, Mycoplasma hominis, and Ureaplasma urealyticum.

An international multilaboratory collaborative study was conducted to develop standard media and consensus methods for the performance and quality control of antimicrobial susceptibility testing of Mycoplasma pneumoniae, Mycoplasma hominis, and Ureaplasma urealyticum using broth microdilution and agar dilution techniques. A reference strain from the American Type Culture Collection was designated for each species, which was to be used for quality control purposes. Repeat testing of replicate samples of each reference strain by participating laboratories utilizing both methods and different lots of media enabled a 3- to 4-dilution MIC range to be established for drugs in several different classes, including tetracyclines, macrolides, ketolides, lincosamides, and fluoroquinolones. This represents the first multilaboratory collaboration to standardize susceptibility testing methods and to designate quality control parameters to ensure accurate and reliable assay results for mycoplasmas and ureaplasmas that infect humans.

ICEPmu1, an integrative conjugative element (ICE) of Pasteurella multocida: structure and transfer.

BACKGROUND: Integrative and conjugative elements (ICEs) have not been detected in Pasteurella multocida. In this study the multiresistance ICEPmu1 from bovine P. multocida was analysed for its core genes and its ability to conjugatively transfer into strains of the same and different genera. METHODS: ICEPmu1 was identified during whole genome sequencing. Coding sequences were predicted by bioinformatic tools and manually curated using the annotation software ERGO. Conjugation into P. multocida, Mannheimia haemolytica and Escherichia coli recipients was performed by mating assays. The presence of ICEPmu1 and its circular intermediate in the recipient strains was confirmed by PCR and sequence analysis. Integration sites were sequenced. Susceptibility testing of the ICEPmu1-carrying recipients was conducted by broth microdilution. RESULTS: The 82 214 bp ICEPmu1 harbours 88 genes. The core genes of ICEPmu1, which are involved in excision/integration and conjugative transfer, resemble those found in a 66 641 bp ICE from Histophilus somni. ICEPmu1 integrates into a tRNA(Leu) and is flanked by 13 bp direct repeats. It is able to conjugatively transfer to P. multocida, M. haemolytica and E. coli, where it also uses a tRNA(Leu) for integration and produces closely related 13 bp direct repeats. PCR assays and susceptibility testing confirmed the presence and the functional activity of the ICEPmu1-associated resistance genes in the recipient strains. CONCLUSIONS: The observation that the multiresistance ICEPmu1 is present in a bovine P. multocida and can easily spread across strain and genus boundaries underlines the risk of a rapid dissemination of multiple resistance genes, which will distinctly decrease the therapeutic options.

ICEPmu1, an integrative conjugative element (ICE) of Pasteurella multocida: analysis of the regions that comprise 12 antimicrobial resistance genes.

BACKGROUND: In recent years, multiresistant Pasteurella multocida isolates from bovine respiratory tract infections have been identified. These isolates have exhibited resistance to most classes of antimicrobial agents commonly used in veterinary medicine, the genetic basis of which, however, is largely unknown. METHODS: Genomic DNA of a representative P. multocida isolate was subjected to whole genome sequencing. Genes have been predicted by the YACOP program, compared with the SWISSProt/EMBL databases and manually curated using the annotation software ERGO. Susceptibility testing was performed by broth microdilution according to CLSI recommendations. RESULTS: The analysis of one representative P. multocida isolate identified an 82 kb integrative and conjugative element (ICE) integrated into the chromosomal DNA. This ICE, designated ICEPmu1, harboured 11 resistance genes, which confer resistance to streptomycin/spectinomycin (aadA25), streptomycin (strA and strB), gentamicin (aadB), kanamycin/neomycin (aphA1), tetracycline [tetR-tet(H)], chloramphenicol/florfenicol (floR), sulphonamides (sul2), tilmicosin/clindamycin [erm(42)] or tilmicosin/tulathromycin [msr(E)-mph(E)]. In addition, a complete bla(OXA-2) gene was detected, which, however, appeared to be functionally inactive in P. multocida. These resistance genes were organized in two regions of approximately 15.7 and 9.8 kb. Based on the sequences obtained, it is likely that plasmids, gene cassettes and insertion sequences have played a role in the development of the two resistance gene regions within this ICE. CONCLUSIONS: The observation that 12 resistance genes, organized in two resistance gene regions, represent part of an ICE in P. multocida underlines the risk of simultaneous acquisition of multiple resistance genes via a single horizontal gene transfer event.

Molecular basis of macrolide, triamilide, and lincosamide resistance in Pasteurella multocida from bovine respiratory disease.

The mechanism of macrolide-triamilide resistance in Pasteurella multocida has been unknown. During whole-genome sequencing of a multiresistant bovine P. multocida isolate, three new resistance genes, the rRNA methylase gene erm(42), the macrolide transporter gene msr(E), and the macrolide phosphotransferase gene mph(E), were detected. The three genes were PCR amplified, cloned into suitable plasmid vectors, and shown to confer either macrolide-lincosamide resistance [erm(42)] or macrolide-triamilide resistance [msr(E)-mph(E)] in macrolide-susceptible Escherichia coli and P. multocida hosts.

Potential Benefits of Limited Clinical and Radiographic Follow-up After Surgical Treatment of Ankle Fractures.

INTRODUCTION: Ankle fractures are one of the most prevalent musculoskeletal injuries, with a significant number requiring surgical treatment. Postoperative complications requiring additional interventions frequently occur during the early postoperative period. We hypothesize that there is a limited need for routine clinical and radiographic follow-up once the fracture is deemed healed. METHODS: IRB approval was obtained at four academic trauma centers. A retrospective chart review was done to identify adults with healed unimalleolar and bimalleolar ankle fractures treated surgically with at least 12 months of follow-up. Based on postoperative radiographs, changes in fracture alignment and implant position from radiographic union to final follow-up were documented. The average reimbursement for a final follow-up clinic visit and a set of ankle radiographs were estimated. RESULTS: A total of 140 patients met inclusion criteria. The mean age at injury was 49.5 years, and 67.9% of patients were female. The mean time to healing was 82.2 days (±33.5 days). After radiographic healing, one patient had radiographic changes but was asymptomatic and full weight bearing at their final follow-up. On average, our institution was reimbursed $46 to $49 for a follow-up clinic visit and $364 to $497 for a set of ankle radiographs. CONCLUSION: Given the average time to healing, there is limited utility in routine radiographic and clinical follow-up beyond 16 weeks in asymptomatic patients. In our series, this would result in a savings of $950 to $1,200 per patient. However, after ankle fractures were deemed healed, 0.7% patients had radiographic evidence of a change in implant position. Documenting this change did not modify the immediate course of fracture treatment. Surgeons will need to balance the need for routine follow-up with the potential economic benefits in reducing costs to the healthcare system.

Correlation between hemolytic activity, cytotoxicity and systemic in vivo toxicity of synthetic antimicrobial peptides.

The use of non-standard toxicity models is a hurdle in the early development of antimicrobial peptides towards clinical applications. Herein we report an extensive in vitro and in vivo toxicity study of a library of 24 peptide-based antimicrobials with narrow spectrum activity towards veterinary pathogens. The haemolytic activity of the compounds was evaluated against four different species and the relative sensitivity against the compounds was highest for canine erythrocytes, intermediate for rat and human cells and lowest for bovine cells. Selected peptides were additionally evaluated against HeLa, HaCaT and HepG2 cells which showed increased stability towards the peptides. Therapeutic indexes of 50-500 suggest significant cellular selectivity in comparison to bacterial cells. Three peptides were administered to rats in intravenous acute dose toxicity studies up to 2-8 × MIC. None of the injected compounds induced any systemic toxic effects in vivo at the concentrations employed illustrating that the correlation between the different assays is not obvious. This work sheds light on the in vitro and in vivo toxicity of this class of promising compounds and provides insights into the relationship between the different toxicity models often employed in different manners to evaluate the toxicity of novel bioactive compounds in general.

Active beta-catenin signaling is an inhibitory pathway for human immunodeficiency virus replication in peripheral blood mononuclear cells.

The Wnt/beta-catenin pathway is involved in cell functions governing development and disease. In modeling postentry restriction of human immunodeficiency virus (HIV) replication in astrocytes, we reported that part of this natural resistance to productive replication of HIV in astrocytes involved expression of proteins of the Wnt/beta-catenin signaling pathway. We determined here whether induction of beta-catenin signaling in peripheral blood mononuclear cells (PBMCs) can modulate HIV replication. Given that lithium is an inducer of beta-catenin signaling, we used it as a tool to determine the impact of beta-catenin signaling on HIV replication in PBMCs. We demonstrated that lithium inhibited the replication of T-tropic and primary isolates of HIV by >90% and did so in noncytotoxic/noncytostatic concentrations and in a beta-catenin-dependent manner. Specifically, inhibiting beta-catenin signaling by transfection of dominant-negative mutant constructs to either T-cell factor 4, the downstream effector of Wnt signaling, or beta-catenin, the central mediator of this pathway, abrogated the ability of lithium to inhibit HIV replication. Moreover, when Wnt/beta-catenin signaling was inhibited, the level of HIV replication was enhanced by fourfold. To confirm the in vivo relevance of the beta-catenin pathway in repressing HIV replication, we evaluated HIV-positive antiretroviral therapy-naive patients who were on lithium therapy. These patients demonstrated a reduction in viral load, which increased as the dose of lithium was reduced. Collectively, these data indicate that beta-catenin signaling is an intrinsic molecular pathway restricting HIV replication in PBMCs.