Antimicrobial resistance and genetic diversity of Klebsiella pneumoniae strains from different clinical sources in horses

Introduction

Klebsiella pneumoniae is a major cause of infections and reproductive disorders among horses, ranked in recent French studies as the sixth most frequently isolated bacterial pathogen in equine clinical samples. The proportion of multidrug-resistant (MDR) K. pneumoniae is therefore significant in a context where MDR K. pneumoniae strains are considered a major global concern by the World Health Organization.

Methods

In this study, we used a genomic approach to characterize a population of 119 equine K. pneumoniae strains collected by two laboratories specialized in animal health in Normandy (France). We describe the main antibiotic resistance profiles and acquired resistance genes, and specify the proportion of virulence-encoding genes carried by these strains. The originality of our panel of strains lies in the broad collection period covered, ranging from 1996 to 2020, and the variety of sample sources: necropsies, suspected bacterial infections (e.g., genital, wound, allantochorion, and umbilical artery samples), and contagious equine metritis analyses.

Results

Our results reveal a remarkable level of genomic diversity among the strains studied and we report the presence of 39% MDR and 9% hypervirulent strains (including 5% that are both MDR and hypervirulent).

Discussion

These findings clearly emphasize the importance of improving the surveillance of K. pneumoniae in routine equine diagnostic tests to detect high-risk MDR-hypervirulent Klebsiella pneumoniae strains. The circulation of these worrisome strains reveals that they are not being detected by the simple K1, K2, and K5 serotype approach currently implemented in the French horse-breeding sector.

Early detection of plasma d-lactate: Toward a new highly-specific biomarker of bacteraemia?

Background

Bloodstream infections are a leading cause of mortality. Their detection relies on blood cultures (BCs) but time to positivity is often between tens of hours and days. d-lactate is a metabolite widely produced by bacteria but very few in human. We aimed to evaluate d-lactate, d-lactate/l-lactate ratio and d-lactate/total lactate ratio in plasma as potential early biomarkers of bacteraemia on a strictly biological standpoint.

Methods

A total of 228 plasma specimens were collected from patients who had confirmed bacteraemia (n = 131) and healthy outpatients (n = 97). Specific l-lactate and d-lactate analyses were performed using enzymatic assays and analytical performances of d-lactate, d-lactate/total lactate and d-lactate/l-lactate ratios for the diagnosis of bacteraemia were assessed.

Results

A preliminary in vitro study confirmed that all strains of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus were able to produce d-lactate at significant levels. In patients, plasma d-lactate level was the most specific biomarker predicting a bacteraemia profile with a specificity and predictive positive value of 100% using a cut-off of 131 μmol.L^-1. However, sensitivity and negative predictive value were rather low, estimated at 31% and 52%, respectively. d-lactate displayed an Area Under Receiver Operating Characteristic (AUROC) curve of 0.696 with a P value < 0.0001. There was no difference of d-lactate levels between BCs bottles positive for Gram-positive or Gram-negative bacteria (p = 0.55).

Conclusion

d-lactate shows promise as a specific early biomarker of bacterial metabolism. The development of rapid automated assays could raise clinical applications for infectious diseases diagnosis including early bacteraemia prediction.

A 10-year microbiological study of Pseudomonas aeruginosa strains revealed the circulation of populations resistant to both carbapenems and quaternary ammonium compounds

Pseudomonas aeruginosa is one of the leading causes of healthcare-associated infections. For this study, the susceptibility profiles to antipseudomonal antibiotics and a quaternary ammonium compound, didecyldimethylammonium chloride (DDAC), widely used as a disinfectant, were established for 180 selected human and environmental hospital strains isolated between 2011 and 2020. Furthermore, a genomic study determined resistome and clonal putative relatedness for 77 of them. During the ten-year study period, it was estimated that 9.5% of patients' strains were resistant to carbapenems, 11.9% were multidrug-resistant (MDR), and 0.7% were extensively drug-resistant (XDR). Decreased susceptibility (DS) to DDAC was observed for 28.0% of strains, a phenotype significantly associated with MDR/XDR profiles and from hospital environmental samples (p < 0.0001). According to genomic analyses, the P. aeruginosa population unsusceptible to carbapenems and/or to DDAC was diverse but mainly belonged to top ten high-risk clones described worldwide by del Barrio-Tofiño et al. The carbapenem resistance appeared mainly due to the production of the VIM-2 carbapenemase (39.3%) and DS to DDAC mediated by MexAB-OprM pump efflux overexpression. This study highlights the diversity of MDR/XDR populations of P. aeruginosa which are unsusceptible to compounds that are widely used in medicine and hospital disinfection and are probably distributed in hospitals worldwide.

[Management of orbital cavernous hemangioma - evaluation of surgical approaches: report of 43 cases]

Cavernous hemangioma is the most frequent benign orbital tumor in adults. The purpose of this study was to examine its clinical features, to define surgical indications, and to determine the roles of the various surgical approaches praticed in ophthalmology: transconjunctival (increasingly utilized), anterior transcutaneous, and lateral orbitotomy. The records of all patients treated for orbital cavernous hemangioma (OCH) since 2004 at the Fondation Rothschild (Paris, France) were retrospectively reviewed. Forty-three patients were treated for orbital cavernous hemangioma. Fifty-eight percent were women, mean age 50.2; 79 % of the tumors were intraconal. Among those patients, 36 underwent surgical removal, 5 were followed periodically, and 2 were lost to follow-up. The main surgical indications were: optic nerve compression (26 patients), proptosis (24 patients) and diplopia (3 patients). Transconjunctival, anterior transcutaneous and Kronlein approaches were used in 16, 12 and 4 patients respectively. Four patients had intrapalpebral hemangiomas easily reached transcutaneously. Two patients demonstrated transient partial 3rd nerve palsy (one with the lateral orbitotomy approach and one with the transconjunctival approach), one patient with the lateral orbitotomy approach developed a palsy of the superior branch of the 3rd nerve, and one patient with the transcutaneous anterior approach developed mydriasis. Surgical excision of OCH's is required in the presence of clinical complications. The transconjunctival approach is a safe technique which can lead to complete resection of the tumor in most cases.

[Multiple involvements of LRP-1 receptor in tumor progression]

Extensive proteolytic remodeling processes constitute a critical step during tumor progression. The endocytic receptor low-density lipoprotein receptor-related protein-1 (LRP-1), by its function in the clearance of multiple extracellular proteases involved in metastatic spreading, has long been considered as a putative tumor suppressor. Moreover, the receptor is likely to control the peritumoral microenvironment by internalization of growth factors and matricial proteins and could therefore participate to the control of signaling events involved in survival and proliferation of cancer cells. Nevertheless, recent data lead to reconsider the initially attributed antitumor properties of LRP-1. A more complex model seems to emerge in which LRP-1 could constitute a sensor of pericellular environment and regulate the membrane proteome dynamics. By its control of focal adhesions composition and turn-over, regulation of the cytoskeleton organization and integrin endocytic recycling, LRP-1 appears as a crucial actor of the epithelial-mesenchymal transition, thereby reinforcing the aggressive phenotype of malignant cells. LRP-1 partitioning into rafts and association with tissue-type and tumor grade specific intracellular scaffold proteins appear crucial to determine its function in tumor progression. Those emerging aspects present numerous promising perspectives in oncology and allow envisaging the development of innovative strategies of control of tumor progression through the targeting of LRP-1.

Possibility of selecting racehorses on jumping ability based on their steeplechase race results in France, the United Kingdom and Ireland

The aim of this study was to detect Thoroughbred mare families and sire lines, in France, in the United Kingdom and Ireland, whose offspring may be successful in steeplechase races and can be recommended therefore for sport horse breeding. Race results were collected from all steeplechase races in these countries between 1998 and 2003, which contained the results of 17,355 horses from 12,861 dams and 2452 sires. In France, non-Thoroughbred horses were also included in the analysis because they race and mate together with Thoroughbreds. Performance was measured with two criteria: earnings and ranks after mathematical transformation. The effects of year, sex, age and race were considered as fixed, animal, permanent environment and maternal environment as random. Precorrection for the effect of race was done to avoid computational difficulties. Maternal environmental components for ranks were 0.02 in France and zero in the United Kingdom and Ireland. Estimated heritabilities for the ranking criteria were 0.18 (repeatability 0.33) in France and 0.06 (repeatability 0.19) in the United Kingdom and Ireland. The high genetic correlation between the two criteria of measurement (0.94 and 0.97 respectively) gives the opportunity to choose the most suitable criteria for breeding value estimation. The ranking value, after statistical normalization has a great advantage for comparison between the countries.

Early evaluation of dressage ability in different breeds

Dressage is one of the Olympic equestrian sports practiced in several countries using different horse breeds. Specific characteristics of the walk, trot and canter are required for dressage. It has been assumed that some of these traits could be selected for genetically and contribute to dressage performance. The purpose of this study was to compare the walk, trot and conformation characteristics in young horses of different breeds used for dressage. A total of 142 horses age 3 years were classified into 3 groups of breeds (German, French and Spanish saddle horses) and tested using the same procedure. The skeletal conformation measurements were made by image analysis. Gait variables of the walk and trot were measured by the accelerometric gait analysis system Equimetrix. Discriminant analysis could explain the variability between the groups by taking into account the walk (P<0.0003), trot (P<0.0001) and conformation variables (P<0.0001). Many gait and conformation variables were significantly different between the breeds. In summary, the German horses had gait characteristics more adapted for dressage competition, and the results of this group could be used as a reference for early evaluation in dressage. Purebred Spanish horses could be considered as a reference for collected gaits used for farm work and old academic dressage. The gait and conformation tests could be applied in a breeding or crossing plan to detect more accurately young horses with good dressage ability.

Mutations in the agouti (ASIP), the extension (MC1R), and the brown (TYRP1) loci and their association to coat color phenotypes in horses (Equus caballus)

Coat color genetics, when successfully adapted and applied to different mammalian species, provides a good demonstration of the powerful concept of comparative genetics. Using cross-species techniques, we have cloned, sequenced, and characterized equine melanocortin-1-receptor (MC1R) and agouti-signaling-protein (ASIP), and completed a partial sequence of tyrosinase-related protein 1 (TYRP1). The coding sequences and parts of the flanking regions of those genes were systematically analyzed in 40 horses and mutations typed in a total of 120 horses. Our panel represented 22 different horse breeds, including 11 different coat colors of Equus caballus. The comparison of a 1721-bp genomic fragment of MC1R among the 11 coat color phenotypes revealed no sequence difference apart from the known chestnut allele (C901T). In particular, no dominant black (ED) mutation was found. In a 4994-bp genomic fragment covering the three putative exons, two introns and parts of the 5'- and 3'-UTRs of ASIP, two intronic base substitutions (SNP-A845G and C2374A), a point mutation in the 3'-UTRs (A4734G), and an 11-bp deletion in exon 2 (ADEx2) were detected. The deletion was found to be homozygous and completely associated with horse recessive black coat color (Aa/Aa) in 24 black horses out of 9 different breeds from our panel. The frameshift initiated by ADEx2 is believed to alter the regular coding sequence, acting as a loss-of-function ASIP mutation. In TYRP1 a base substitution was detected in exon 2 (C189T), causing a threonine to methionine change of yet unknown function, and an SNP (A1188G) was found in intron 2.

Heritability of percentage of fast myosin heavy chains in skeletal muscles and relationship with performance

The purpose of this study was to determine the percentage of fast myosin heavy chains (fast MHCs = MHC 2A + 2B) in 2 propelling muscles to estimate the heritability and to identify any relationship with performance. The gluteus medius and the biceps femoris muscles were biopsied in 100 related French Anglo-Arabian horses. The percentages of slow and fast myosin heavy chains were measured using an ELISA technique. The heritability (s.e.) of the fast MHCs percentage was estimated at 13% (0.1) using a restricted maximum likelihood resolution of a mixed animal model. There were significant (P < 0.05) correlations between the performance level and the fast MHCs percentage of the gluteus medius and biceps femoris muscles: 0.47 and 0.34 respectively. An analysis of variance revealed a significant (P < 0.05) effect of performance level in gallop racing and show jumping on the fast MHCs percentage of the gluteus medius muscle. The good performers in gallop racing (75.5 > 69.6% fast MHCs) and show jumping (74.1 > 67.8% fast MHCs) had a higher percentage of fast MHCs in the gluteus medius than poor performers (P < 0.05). This muscular analysis could be one of the interesting physiological traits to measure for early selection of gallop racing and show jumping horses.

[Anaesthesia and post-operative care in diabetic patients. Constant rate insulin infusion throughout surgery (author's transl)]

In 10 diabetic patients about to undergo surgical procedures requiring prolonged fasting, a constant rate infusion of glucose (200 g/24 hours) and insulin (2 units/hour) was set up on the morning of the operation. Seven of these patients were insulin-dependent. Throughout the pre-, per- and post-operative periods blood glucose levels were monitored and kept between 0,9 and 1,75 g/l through adjustment of insulin dosage by half units/hour. Treatment lasted from 2 to 7 days. The highest mean doses of insulin were given, and the greatest disparity of results was observed, during the first 24 hours following surgery. Insulin requirements were thereafter stable. This technique simplifies anaesthesia and post-operative care in diabetic patients. The operation time does not need to be precisely determined, small doses of insulin are easily adjusted, insulin therapy is safely and regularly maintained before, during and after surgery, and return to the initial maintenance dosage is facilitated by the disappearance of residual insulin within 3 to 5 minutes from the end of the infusion period.