Dogs can detect an odor profile associated with Staphylococcus aureus biofilms in cultures and biological samples

Introduction

The study investigated the utilization of odor detection dogs to identify the odor profile of Staphylococcus aureus (S. aureus) biofilms in pure in vitro samples and in in vivo biosamples from animals and humans with S. aureus periprosthetic joint infection (PJI). Biofilms form when bacterial communities aggregate on orthopedic implants leading to recalcitrant infections that are difficult to treat. Identifying PJI biofilm infections is challenging, and traditional microbiological cultures may yield negative results even in the presence of clinical signs.

Methods

Dogs were trained on pure in vitro S. aureus biofilms and tested on lacrimal fluid samples from an in vivo animal model (rabbits) and human patients with confirmed S. aureus PJI.

Results

The results demonstrated that dogs achieved a high degree of sensitivity and specificity in detecting the odor profile associated with S. aureus biofilms in rabbit samples. Preliminary results suggest that dogs can recognize S. aureus volatile organic compounds (VOCs) in human lacrimal fluid samples.

Discussion

Training odor detection dogs on in vitro S. aureus, may provide an alternative to obtaining clinical samples for training and mitigates biosecurity hazards. The findings hold promise for culture-independent diagnostics, enabling early disease detection, and improved antimicrobial stewardship. In conclusion, this research demonstrates that dogs trained on in vitro S. aureus samples can identify the consistent VOC profile of PJI S. aureus biofilm infections. The study opens avenues for further investigations into a retained VOC profile of S. aureus biofilm infection. These advancements could revolutionize infectious disease diagnosis and treatment, leading to better patient outcomes and addressing the global challenge of antimicrobial resistance.

Retrospective evaluation and review of approaches for nonspecific lameness in dogs presented to an emergency service (2013-2014): 134 cases

OBJECTIVE

This retrospective study aimed to characterize and evaluate the emergency approach, diagnosis, management, treatment, and follow-up of nonspecific canine lameness cases.

DESIGN

Retrospective case series from September 25, 2013 to September 25, 2014.

SETTING

The study was conducted at an urban university teaching hospital.

ANIMALS

A consecutive sample of dogs presenting to the emergency service with nonspecific lameness in the designated timeframe was used to identify 134 cases. Owners were contacted to participate in the follow-up survey; dogs that died prior to data collection were excluded from the survey. Medical records were reviewed for lameness localization, etiology of lameness, diagnostics obtained, medications prescribed, and owner recommendations.

INTERVENTIONS

Based on review of the medical records, the lameness localization, presumptive source of lameness (joint, soft tissue, neurological, or bone), diagnostics obtained, medications prescribed, and owner recommendations were recorded. Survey data included duration of lameness, perceived response to treatment, and activity level.

MEASUREMENTS AND MAIN RESULTS

Definitive diagnoses were not assigned in 88.8% of lameness cases. A presumptive diagnosis of soft tissue injury was assigned in 45.3% of cases. Single limb lameness was more prevalent than multiple limb lameness. Owners whose dogs were treated with medication were significantly more likely to report that the lameness resolved (P = 0.049). Dogs with injury localized to ≥1 of the joints were significantly less likely to have resolution of lameness (P = 0.037). Treatment recommendations were predominantly pain control and activity restriction.

CONCLUSIONS

Nonspecific lameness represents approximately 4% of canine urban emergency cases. Highlighting the points of clinical care considerations in understanding the etiology of lameness in dogs represents an opportunity for improved patient care and growth in emergency referral and follow-up.

Rehabilitation to Return-to-Work for Working Dogs

This article highlights the differences between working dog careers, unique protocols associated with health care of a working dog and provides a practical guide to creating and managing a return-to-work program. The rehabilitative approach to a working dog consists of four distinct sequential phases: activity restriction, rehabilitation, return-to-work, and maintenance. The timeline through each phase is dependent on the degree of injury, treatment intervention, prior health status of the dog, and compliance of the handler. Return-to-work for a working dog is considered a success if the dog can perform all career-related activities safely and proficiently.

Canine Mobility Maintenance and Promotion of a Healthy Lifestyle

This article highlights the recommendations and considerations for maintaining a healthy canine lifestyle. A key component of a healthy lifestyle is the enhancement and optimization of mobility. Mobility is essential in maintaining a high quality of life and involves the interplay of a dog's structure, posture, body condition score, physical exercise, and a healthy human-animal bond throughout a dog's lifetime.

The Penn Vet Working Dog Center Fit to Work Program: A Formalized Method for Assessing and Developing Foundational Canine Physical Fitness

Fit to Work is a formalized working dog foundational physical fitness assessment and development program. The Penn Vet Working Dog Center developed this program to address the needs of working dog handlers, trainers, and programs for simple, effective, and efficient methods to develop and assess working dog physical fitness. Fit to Work focuses on the foundational fitness modalities of strength, stability, mobility, and proprioception. The Penn Vet Working Dog Center piloted and refined this program over 3 months in a closed population of 31 working dogs in training. Fit to Work consists of posture development and maintenance, warm-up and cool-down routines, training exercises, and assessment methods. To simplify implementation for dogs and personnel, the foundational training program incorporates a discrete number of exercises, standardized progression steps, defined criteria for progression, and a reduced emphasis on learned behaviors. Fit to Work also enables safe and progressive assessment of foundational fitness through a tiered and inexpensive process. Future research will focus on validation of training and assessment methods, development of assessment standards, and correlation of physical fitness with operational performance.

Working Dogs Drinking a Nutrient-Enriched Water Maintain Cooler Body Temperature and Improved Pulse Rate Recovery After Exercise

Exercise-related physiological changes were evaluated in hydrated, exercise-conditioned working dogs with free access to tap water (TW) with or without a nutrient-enriched water supplement (NW). Physiological samples and measures were collected before and after work-related field tasks in a warm and moderately humid ambient environment. In a cross-over design study, 12 dogs (age range 8-23 months) were evaluated on 3 separate occasions within each period with exercise bouts up to 30 min, on days -4, 3, and 11. Dogs were offered either ad libitum TW or portion-controlled NW daily plus ad libitum TW. Prior to and serially after exercise, pulse rate (PR), core (BT_core) and ear (BT_ear) temperature were recorded. Urine was collected first thing in the morning, whereas blood samples collected and body weight (BW) recorded pre- and immediately post exercise. Ambient temperature was above 21.7°C (71°F) and relative humidity ranged from 36 to 76%. Activity parameters, AM urine measures, post-exercise percent change of BW, resting PR and resting BT_core did not differ between treatment groups on any exercise day. At the completion of exercise, mean BT_core for all dogs ranged from 104.8 to 105.6°F. Immediate post-exercise BT_ear was always lower compared to BT_core and means ranged from 103.3 to 104.0°F. The effect of time was highly significant (P < 0.001) for both BT measures with both BT_core and BT_ear recovering to resting levels by 60 min post exercise. PR and several blood values showed a significant main effect of time. Over the recovery period, dogs in the NW group had lower mean BT_ear and PR by 0.6°F and 3.4 bpm, respectively. Daily ingestion of a NW in combination with free access to TW can reduce the post-exercise-related BT_core and BT_ear hyperthermia, and improve pulse rate recovery following exercise in this population of working dogs undergoing 30 min bout of exercise.

Environmental and Physiological Factors Associated With Stamina in Dogs Exercising in High Ambient Temperatures

This IACUC approved study was performed to evaluate the environmental, physiological, and hematological components that contribute to stamina following successive bouts of exercise that included searching (5-min), agility (5-min), and ball retrieve (<10-min). Regularly exercised dogs (N = 12) were evaluated on five separate occasions. The population consisted of eight males and four females ranging in age from 8 to 23 months, which included six Labrador retrievers, three German shepherds, and one each English springer spaniel, German wirehaired pointer, and Dutch shepherd. The exercise period was up to 30 min with 5 min of intermittent rest between the exercise bouts or until a designated trainer determined that the dog appeared fatigued (e.g., curled tongue while panting, seeking shade, or voluntary reluctance to retrieve). At the end of the exercise period, pulse rate (PR), core temperature, blood lactate, and venous blood gas were collected. The median outdoor temperature was 28.9°C (84°F) (IQR; 27.2–30°C/81–86°F) and median humidity was 47% (IQR; 40–57%). Median duration of exercise was 27 min (IQR; 25–29). No dog showed signs of heat stress that required medical intervention. The components used to measure stamina in this study were total activity, post-exercise core body temperature (CBT), and increase in CBT. When controlling for breed, total activity, as measured by omnidirectional accelerometer device, could be predicted from a linear combination of the independent variables: pre-exercise activity (p = 0.008), post-exercise activity (p < 0.001), outdoor temperature (p = 0.005), reduction in base excess in extracellular fluid compartment (BEecf) (p = 0.044), and decrease in TCO₂ (p = 0.005). When controlling for breed and sex, increase in CBT could be predicted from a linear combination of the independent variables: study day (p = 0.005), increase in PR (p < 0.001), increase in lactate (p = 0.001), reduction in BEecf (p = 0.031), increase in glucose (p = 0.044), increase in hematocrit (p = 0.032), and increase in hemoglobin (p = 0.038). This study suggests that the influence of outdoor temperature, pre- and post-exercise activity, and the metabolic parameters are important components of stamina associated with exertion.

RESULTADOS DE TESTES DE CULTURA E ANTIBIOGRAMA EM SEIS CASOS DE ÚLCERA CORNEANA EM EQUINOS

A ulceração corneana é uma desordemimportante nos olhos eqüinos, podendo levará cegueira se não tratada adequadamente. Esteestudo retrospectivo tem por objetivo mostrar a importânciado conhecimento da microbiota comensalde olhos eqüinos, para que, em caso de ulceraçãocorneana, o tratamento seja empregado de formarápida, enquanto aguardam-se resultados dos testesde cultura e antibiograma para possível ajuste na terapia.

Intramolecular Friedel-Crafts-type reactions involving N-acyliminium ions derived from glycine templates

Enantiomerically pure 4-substituted 2-aralkyl-2,4-dihydro-1H-pyrazino[2,1-b]quinazoline-3,6-diones (1b-m) in which the alkyl chain is (CH(2))(n), n = 1-3, behave as glycine templates giving by treatment with [hydroxy(tosyloxy)iodo]benzene in ethyl acetate cis-1-tosyloxy derivatives. When these compounds contain electron-rich aryl substituents with n = 2, they spontaneously cyclize through intramolecular Friedel-Crafts-type diastereoselective reactions to give penta- or hexacyclic compounds. Otherwise, they give by solvolysis cis-1-alkoxy derivatives, which in a second step, may be cyclized in acid if n = 2, 3. All these reactions must occur through N-acyliminium species in S(N)1-like mechanisms. 1-Alkoxy-2-arylmethyl derivatives are reluctant to cyclize, giving trans-1-hydroxy compounds as the only isolated reaction products.

Molecular bureaucracy: who controls the delays? Transient times in branched pathways and their control

Analysis of metabolic control has until now been mainly confined to systems at steady state. This includes studies of the control of "transition time", which is actually a steady-state transit time that does not refer to the transient state. In this paper we examine the control of the transition state of a metabolic pathway in the approach to a stable steady state, showing that the time needed to attain it can be decreased or increased in different branches. Our analysis only applies to branched pathways, and we discuss why similar deviations cannot occur in unbranched pathways. In systems with several branches the acceleration of some branches during the transient phase, so that they reach their steady states more quickly, occurs at the expense of others, which are thus delayed. We present theorems that describe properties of the transient variables and their control.

Synthesis and antitumour activity of fluorinated 1-aza and 1,8-diazaanthraquinones

A series of 3-fluoro-1-aza- and 1,8-diazaanthraquinones, structurally related to the antitumour antibiotic diazaquinomycin A, have been prepared by Diels-Alder reactions of 2-fluoro-2-propenal N, N-dimethylhydrazone and the corresponding quinones. These compounds showed potent in vitro activity against different tumour cell lines. They also showed some selectivity towards rapid-growth tumours when compared to other non-fluorinated analogues. In contrast with diazaquinomycin A, the azaanthraquinones studied here have not shown significant activity as thymidylate synthase inhibitors. Some compounds showed a high activity as inhibitors of protein, DNA and RNA biosynthesis.

Cerebrospinal fluid beta 2-microglobulin in neonates with central nervous system infections

Beta 2-microglobulin (beta 2m) determination in CSF of 72 neonates who underwent a spinal tap as part of a sepsis or meningo-encephalitis workup was performed to evaluate the usefulness of this test in the diagnosis of CNS infections. Beta 2m was measured by enzyme immunoassay. Sixty neonates had sterile culture and normal neurological status at discharge. Twelve infants had CNS infections: 8 bacterial meningitis, 3 TORCH infections (T = toxoplasmosis, O = others, R = rubella, C = cytomegalovirus and H = herpes simplex) and 1 viral meningitis. Neonates with CNS infection exhibited significantly higher CSF beta 2m levels compared to neonates with sterile culture (6.24 +/- 2.66 vs 1.74 +/- 0.5 mg/l; P < 0.0001). CSF beta 2m levels did not correlate with the white cell count, total protein concentration or glucose level in CSF. When serum and CSF levels were measured simultaneously, the CSF beta 2m level was significantly higher than the corresponding serum level in patients with CNS infection (6.98 +/- 2.5 vs 3.2 +/- 0.25 mg/l; P < 0.01). Sensitivity, specificity, and predictive values were estimated for different cut-off points. The best operational diagnostic cut-off value was 2.25 mg/l. Receiver operating characteristic curve analysis showed an appropriate trade-off between specificity and sensitivity and indicated that CSF beta 2m was accurate in distinguishing between neonates with and without CNS infection. Conclusion. CSF beta 2m may be a useful ancillary tool in neonates when CNS infection is suspected.