An individual-based model of transmission of resistant bacteria in a veterinary teaching hospital

An agent-based model on antimicrobial de-escalation in intensive care units: Implications on clinical trial design

Antimicrobial de-escalation refers to reducing the spectrum of antibiotics used in treating bacterial infections. This strategy is widely recommended in many antimicrobial stewardship programs and is believed to reduce patients' exposure to broad-spectrum antibiotics and prevent resistance. However, the ecological benefits of de-escalation have not been universally observed in clinical studies. This paper conducts computer simulations to assess the ecological effects of de-escalation on the resistance prevalence of Pseudomonas aeruginosa-a frequent pathogen causing nosocomial infections. Synthetic data produced by the models are then used to estimate the sample size and study period needed to observe the predicted effects in clinical trials. Our results show that de-escalation can reduce colonization and infections caused by bacterial strains resistant to the empiric antibiotic, limit the use of broad-spectrum antibiotics, and avoid inappropriate empiric therapies. Further, we show that de-escalation could reduce the overall super-infection incidence, and this benefit becomes more evident under good compliance with hand hygiene protocols among health care workers. Finally, we find that any clinical study aiming to observe the essential effects of de-escalation should involve at least ten arms and last for four years-a size never attained in prior studies. This study explains the controversial findings of de-escalation in previous clinical studies and illustrates how mathematical models can inform outcome expectations and guide the design of clinical studies.

Inflammatory, Mechanical and Infectious Complications Associated with Peripheral Intravenous Catheters in Dogs and Cats: A Risk Factor Analysis

The placement of peripheral intravenous catheters (PIVC) is potentially associated with complications that negatively impact healthcare. Our study investigated factors associated with the occurrence of PIVC-related complications in dogs and cats at a Veterinary Teaching Hospital. The second aim was to determine the prevalence of PIVC bacterial colonization. A total of 76 dogs and 40 cats with PIVCs were evaluated for the occurrence of phlebitis and mechanical complications. The devices were removed when they ceased to be functional or when complications occurred, and the content was submitted for bacterial cultures and antimicrobial susceptibility tests. Both multivariable linear regression models and ROC analysis were employed. Complications were recorded in 46.6% of cases, and 20.7% of catheters yielded a positive culture. Among the isolates, 45% were classified as multi-resistant. In dogs, a ≥36-h indwelling time was associated with an increased risk of complications. Male cats seem more prone to developing complications, while the insertion of PIVCs under sedation may represent a protective factor in this species. In conclusion, PIVC-associated complications were frequently observed, and the high rate of positive culture for PIVCs, together with the presence of multi-resistant isolates, is a cause of concern in a hospital setting.

Investigation of the environmental presence of multidrug-resistant bacteria at small animal hospitals in Hungary

Multidrug-resistant bacteria can cause severe nosocomial infections in both human and veterinary clinics. The aim of this study was to investigate the presence and antibiotic susceptibility of Enterococcus, Staphylococcus and Pseudomonas strains at four small animal clinics of Hungary in 2018, as these bacteria can reliably represent the level of antimicrobial resistance in the investigated environment. A total of 177 Staphylococcus colonies were found, including 22 Staphylococcus pseudintermedius and 13 Staphylococcus aureus. As regards enterococci, 9 Enterococcus faecium, 2 E. faecalis and further 286 Enterococcus strains were isolated. The number of Pseudomonas aeruginosa isolates (n = 34) was considered too low for relevant susceptibility testing. Among staphylococci, the highest resistance was found to sulphamethoxazole (82.9%), penicillin (65.7%) and erythromycin (54.3%), while in the case of enterococci, resistance to norfloxacin and rifampicin was the most common, with 25.5% of the strains being resistant to both antibiotics. Ten methicillin-resistant S. pseudintermedius (MRSP) and six vancomycin-resistant Enterococcus (VRE) strains could be identified. Only 5.7% of the Staphylococcus isolates were susceptible to all tested agents, while this ratio was 36.2% among enterococci. The results of this study have revealed a high prevalence of antibiotic-resistant bacteria in Hungarian small animal clinics, which highlights the importance of regular disinfection processes and stringent hygiene measures in veterinary clinics.

Evaluation of the Resistance Profile of Bacteria Obtained From Infected Sites of Dogs in a Veterinary Teaching Hospital in Brazil: A Retrospective Study

The aim of this study was to evaluate the prevalence and antimicrobial resistance profile of bacterial species isolated from infected sites of canines. All samples were collected from canine patients who received clinical or surgical care at the veterinary teaching hospital between March 2016 and November 2017. The samples were analyzed in a private pathology laboratory. A descriptive analysis of 295 antimicrobial susceptibility test reports was performed. Staphylococcus spp. (104/295 [35.25%]), Escherichia coli (100/295 [33.90%]), Proteus spp. (44/295 [14.92%]), Pseudomonas spp. (25/295 [8.47%]), and Klebsiella spp. (20/295 [6.78%]) were more frequently isolated, and a high incidence of multidrug resistance was observed (69,83% [206/295]). Methicillin-resistant Staphylococcus spp. accounted for 33% (33/100) of the Staphylococcus strains. Enterobacteriaceae cefotaxime resistance constituted 22.82 ± 4.49% and Enterobacteriaceae imipenem resistance constituted 5% (1/20) for Klebsiella spp., 5% (5/100) for E coli, and 6.82% (3/44) for Proteus spp. Pseudomonas spp. strains accounted for 8% (2/25) of imipenem resistance and 45.45% (10/22) of polymyxin B resistance. Our findings revealed a high rate of multidrug-resistant bacteria involvement in the infectious process of dogs. From the perspective of the One Health scenario, our results showed alarming data, given the high risk of resistant-strain dissemination between animals, owners, and healthcare professionals. There is an urgent need for strategies to control and prevent the evolution of new multidrug-resistant bacteria in veterinary hospitals. It is also crucial to understand and emphasize the role of veterinary professionals in this public health battle.

A survey of within-host and between-hosts modelling for antibiotic resistance

Antibiotic resistance is a global public health problem which has the attention of many stakeholders including clinicians, the pharmaceutical industry, researchers and policy makers. Despite the existence of many studies, control of resistance transmission has become a rather daunting task as the mechanisms underlying resistance evolution and development are not fully known. Here, we discuss the mechanisms underlying antibiotic resistance development, explore some treatment strategies used in the fight against antibiotic resistance and consider recent findings on collateral susceptibilities amongst antibiotic classes. Mathematical models have proved valuable for unravelling complex mechanisms in biology and such models have been used in the quest of understanding the development and spread of antibiotic resistance. While assessing the importance of such mathematical models, previous systematic reviews were interested in investigating whether these models follow good modelling practice. We focus on theoretical approaches used for resistance modelling considering both within and between host models as well as some pharmacodynamic and pharmakokinetic approaches and further examine the interaction between drugs and host immune response during treatment with antibiotics. Finally, we provide an outlook for future research aimed at modelling approaches for combating antibiotic resistance.

Treatment of a femoral septic nonunion in a dog with interlocking nail stabilization associated to corticospongious bone autograft and greater omentum flap: case report

ABSTRACT Chronic septic bone nonunion requires a well-designed therapeutic planning, demanding a multimodal treatment to achieve bone consolidation and elimination of infection. A successful case of an association of the major omentum flap with surgical stabilization with an interlocking nail for treatment of a femoral septic nonunion in dog is reported. The patient had partial functional return of the limb 30 days after surgery, negative bacterial culture with radiographic signs of bone healing and total functional return of the limb at 90th days after the surgical procedure.

Aislamiento e identificación de bacterias con potencial nosocomial procedentes de ambientes y superficies de una clínica veterinaria Universitaria del Área Metropolitana del Valle de Aburrá, Antioquia-Colombia

Introducción: las infecciones nosocomiales son aquellas adquiridas por los pacientes durante la hospitalización. Son de gran importancia en medicina humana pero aún se desconoce cuál es su papel en medicina veterinaria.Objetivo: identificar la presencia de bacterias asociadas a infecciones hospitalarias en ambientes y superficies en una clínica veterinaria.Materiales y métodos: se realizaron dos muestreos, se determinó a través de sedimentación y torunda la presencia de bacterias en el ambiente y las superficies de las 8 unidades de la clínica veterinaria. La presencia de nosocomiales se determinó por el crecimiento y purificación en medios diferenciales, la identificación se hizo por descripción macroscópica de las colonias y tinción de Gram y posteriormente se realizó una caracterización bioquímicamente por medio del API20E y API50 CH/E y un antibiograma en las cepas relacionadas con resistencia a antibióticos.Resultados: se obtuvo 95 aislados y se logró determinar la presencia de 28 agentes potencialmente nosocomiales, donde se destaca la presencia de Pseudomonas aeruginosa, Proteus sp. y Staphylococcus sp. microorganismos relacionados con infecciones asociadas a hospitales veterinarios.Conclusiones: se realiza la primera aproximación a este tipo de infecciones en hospitales veterinarios en Antioquia, y se evidencia la circulación en ambiente y superficies de potenciales bacterias nosocomiales en la clínica veterinaria.

Types of Wounds and the Prevalence of Bacterial Contamination of Wounds in the Clinical Practice of Small Animals

Skin wounds are a common presentation in small animal practice. The successful management of wound healing in dogs and cats requires knowledge of the physiology of the wound healing process and the application of an appropriate therapeutic intervention. Many wounds are colonised by bacteria or show signs of clinical infection. Infections can delay wound healing, impair cosmetic outcome and increase healthcare costs. Because of a lack of papers giving an overall prevalence of bacteria in different types of wounds, 45 samples were taken from patients treated at the Small Animals Clinic, Section of Surgery, Orthopaedics, Roentgenology and Reproduction of the University of Veterinary Medicine and Pharmacy in Košice during the years 2017 — 2018 to determine the types of wounds and the prevalence of bacterial contamination of the wounds. Samples were obtained by using cotton-tipped swabs and then cultivated on Sabouraud’s plates in the Institute of Microbiology and Gnotobiology of the University. All 45 animals used in this research were first subjected to an anatomical and clinical exam to determine the patient’s health condition and the status of the wounds. Of these 45 samples, 9 were negative. Of the remaining 36 samples, 12 were cultivated and tested to give only the genera of the bacteria present, whilst 24 were tested more extensively for a specific diagnosis of the species. The most common wound was due to a bite from another animal; these made up 12 out of the 45 cases (26.67 %). There were 10 cases of dehiscence of old wounds (22.22 %), whereas there were only 2 cases of surgical wound complications (4.44 %). There were 5 puncture wounds or fistulas (11.11 %), 4 lacerations (8.88 %), 1 degloving injury (2.22 %), 1 seroma (2.22 %), 1 foreign body (2.22 %), 1 crushing injury (2.22 %), 1 case of contusion and necrosis (2.22 %), 1 cases of dermatitis with resulting pruritic lesions (2.22 %), and 1 cutting injury from a tight wire collar (2.22 %). Five cases (11.11 %) were wounds of unknown aetiology. The most commonly found bacteria was Staphylococcus intermedius, which was found in 14 out of the 45 wounds (31.11 %). From this study it appears that the first consideration for treatment of infected wounds should be a treatment plan which will have a high efficacy against Staphylococcus spp. However, despite the high prevalence of Staphylococcus spp., our results revealed that they are not present all of the time.

Send more data: a systematic review of mathematical models of antimicrobial resistance

Background

Antimicrobial resistance is a global health problem that demands all possible means to control it. Mathematical modelling is a valuable tool for understanding the mechanisms of AMR development and spread, and can help us to investigate and propose novel control strategies. However, it is of vital importance that mathematical models have a broad utility, which can be assured if good modelling practice is followed.

Objective

The objective of this study was to provide a comprehensive systematic review of published models of AMR development and spread. Furthermore, the study aimed to identify gaps in the knowledge required to develop useful models.

Methods

The review comprised a comprehensive literature search with 38 selected studies. Information was extracted from the selected papers using an adaptation of previously published frameworks, and was evaluated using the TRACE good modelling practice guidelines.

Results

None of the selected papers fulfilled the TRACE guidelines. We recommend that future mathematical models should: a) model the biological processes mechanistically, b) incorporate uncertainty and variability in the system using stochastic modelling, c) include a sensitivity analysis and model external and internal validation.

Conclusion

Many mathematical models of AMR development and spread exist. There is still a lack of knowledge about antimicrobial resistance, which restricts the development of useful mathematical models.

Application of dynamic modelling techniques to the problem of antibacterial use and resistance: a scoping review

Selective pressure exerted by the widespread use of antibacterial drugs is accelerating the development of resistant bacterial populations. The purpose of this scoping review was to summarise the range of studies that use dynamic models to analyse the problem of bacterial resistance in relation to antibacterial use in human and animal populations. A comprehensive search of the peer-reviewed literature was performed and non-duplicate articles (n = 1486) were screened in several stages. Charting questions were used to extract information from the articles included in the final subset (n = 81). Most studies (86%) represent the system of interest with an aggregate model; individual-based models are constructed in only seven articles. There are few examples of inter-host models outside of human healthcare (41%) and community settings (38%). Resistance is modelled for a non-specific bacterial organism and/or antibiotic in 40% and 74% of the included articles, respectively. Interventions with implications for antibacterial use were investigated in 67 articles and included changes to total antibiotic consumption, strategies for drug management and shifts in category/class use. The quality of documentation related to model assumptions and uncertainty varies considerably across this subset of articles. There is substantial room to improve the transparency of reporting in the antibacterial resistance modelling literature as is recommended by best practice guidelines.