Basal plasma concentrations of routine variables and packed cell volume in clinically healthy adult small-sized dogs: effect of breed, body weight, age, and gender, and establishment of reference intervals.

BACKGROUND: Plasma variables may be affected by breed or body weight (BW). Small-sized dogs are very common, but no specific reference intervals (RI) are used. OBJECTIVES: The primary objective of this prospective study was to assess the potential effect of breed, BW, age, and sex on routine plasma analytes and packed cell volume (PCV) in small-sized dogs. A secondary objective was to establish RI in this small-sized population. METHODS: Blood was sampled under standardized conditions from healthy dogs. PCV and 15 routine plasma variables were measured at the same laboratory. Effects of breed, BW, age, and sex were tested using a general linear model. The procedure recommended by the Clinical and Laboratory Standards Institute was used to establish RI. RESULTS: In this study, 154 healthy dogs from 7 breeds were prospectively included. Although a significant effect of breed, BW, sex, or age was evidenced for most variables (except plasma sodium, phosphates, and triglycerides), it was considered as clinically irrelevant. More strikingly, the percentage of values in the reference sample group under the lower limit of the laboratory's RI ranged from 3.8% to 76.6% for 9 variables, and those higher than the upper limit of the laboratory's RI ranged from 4.5% to 9.7% for 7 variables. For example, the RI for creatinine in small-sized dogs was 45-90 µmol/L (vs 54-144 µmol/L for the general dog population). CONCLUSION: Specific RI should be considered for PCV and selected plasma variables in small-sized dogs.

High prevalence of blaCTX-M-1/IncI1/ST3 and blaCMY-2/IncI1/ST2 plasmids in healthy urban dogs in France.

In the community, close contacts between humans and dogs may promote the transfer of extended-spectrum beta-lactamase/plasmidic AmpC cephalosporinase (ESBL/pAmpC) genes. Large-scale prevalence studies on ESBL/pAmpC carriage in dogs are rare, and data on ESBL/pAmpC plasmids are even more limited. Here, a considerable rate of 18.5% ESBL/pAmpC carriers was found among 368 unrelated healthy dogs in Paris, France. This prevalence is much higher than the one found in healthy humans in the same city (6%) but close to that recently reported in dogs in China (24.5%). All isolates were identified as Escherichia coli, except one Salmonella enterica and one Klebsiella pneumoniae isolate. The sequence type 131 (ST131) clone was rare (2/73 isolates). Interestingly, two plasmids (blaCTX-M-1/IncI1/ST3 and blaCMY-2/IncI1/ST2) were unexpectedly highly predominant, raising the question of their successful spread. Considering that CTX-M-1 was recently found to be equally as abundant as CTX-M-15 in healthy Parisian subjects, the question of dogs being a CTX-M-1 reservoir for humans is open. Such a high prevalence of the blaCMY-2/IncI1/ST2 plasmid may result from the use of cephalexin in veterinary medicine, as previously demonstrated experimentally. In all, our study points out healthy urban dogs as a potential source of ESBL/pAmpC genes that can further disseminate to the human community.

Risk factors for urinary tract infection with multiple drug-resistant Escherichia coli in cats.

The emergence of multiple drug-resistant (MDR) bacteria is a growing public health problem. The objective of this retrospective study was to identify risk factors associated with MDR Escherichia coli infection of the urinary tract in cats. All cats presenting with an E coli urinary infection between March 2010 and December 2012 were included and divided into two groups: an MDR group and a non-MDR group. The effects of different variables on the occurrence of an MDR E coli infection were evaluated: age, sex, additional diseases, number of antibiotics and number of days of hospitalisation. Fifty-two cats were identified (10 MDR and 42 non-MDR). The number of antibiotic groups used within the last 3 months was associated with an increased risk of MDR E coli urinary infection (P = 0.007). The association of the number of days of hospitalisation within the last 3 months and the increased risk of MDR E coli urinary infection did not reach significance (P = 0.090). This study provides evidence that systematic urinary culture with antibiotic sensitivity testing should be recommended when treating urinary tract infections if antibiotics have been prescribed within the past 3 months. Moreover, the selection of MDR bacteria through antibiotic use should be considered as a potential risk associated with treatment.

Characterisation of clinical canine meticillin-resistant and meticillin-susceptible Staphylococcus pseudintermedius in France.

Staphylococcus pseudintermedius is a frequent pathogen in dogs. The emergence of meticillin-resistant S. pseudintermedius (MRSP), which is concomitantly resistant to nearly all veterinary licensed antibiotics used for systemic treatment in dogs, is a major problem for veterinarians. In France, 16.9% (41/243) of the S. pseudintermedius collected in 2010 were MRSP. They mainly belonged to the multiresistant MLST sequence type ST71, spa type t02, SCCmec type II-III (ST71-t02-II-III) European clone. Moreover, we also report the emergence of multiresistant meticillin-susceptible S. pseudintermedius isolates presenting atypical and/or new spa types. This study highlights the need for surveillance, optimised treatment guidelines and new therapeutic alternatives.

Is it possible to use expired tubes for routine biochemical analysis in dogs?

BACKGROUND: Expired collection tubes may be used inadvertently and resampling is not always possible. To date, studies have not been conducted in veterinary medicine to determine whether or not biochemical measurements obtained from specimens collected into expired tubes are accurate enough for clinical decision-making. OBJECTIVES: The aims of this preliminary study were to assess the impact of measuring routine plasma biochemical analytes in canine specimens collected in expired tubes and to investigate the relationship between post-expiration time and the magnitude of errors. METHODS: Blood specimens were collected from 61 dogs and aliquoted equally into tubes containing lithium heparin and gel. One tube was within the expiration date, and the other tube was up to 11 months post-expiration. Plasma was separated within 1 hour of specimen collection, and concentrations of urea, creatinine, total protein, albumin, total bilirubin, cholesterol, triglycerides, magnesium, calcium, phosphates, sodium, potassium, chloride, total CO(2), and fructosamine and activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase (ALP), γ-glutamyltransferase, lactate dehydrogenase, creatine kinase, amylase, and lipase were analyzed immediately and results compared. RESULTS: For most analytes there was no significant difference between results from specimens collected in non-expired and expired tubes. For ALP and lipase activities and fructosamine and total CO(2) concentrations, significant differences were found, and results obtained for fructosamine and total CO(2) from specimens in expired tubes may have led to erroneous interpretations. The effect of time since expiration was constant over time. CONCLUSIONS: When specimens are processed within 1 hour of collection, results of routine biochemical measurements of blood collected in lithium heparin tubes remain clinically valid for up to 11 months after expiration of tubes for the majority of analytes, except for ALP, lipase, fructosamine, and total CO(2).

A USA300 variant and other human-related methicillin-resistant Staphylococcus aureus strains infecting cats and dogs in France.

OBJECTIVES: To characterize methicillin-resistant Staphylococcus aureus (MRSA) clinical strains from cats and dogs in France, and to compare the clones identified with the distribution of French human MRSA. METHODS: Susceptibilities to antimicrobials were assessed by disc diffusion. Resistance and virulence genes were screened using a microarray-based assay. Isolates were additionally characterized by SmaI macrorestriction analysis and spa typing. RESULTS: From 2006 to 2010, the proportion of MRSA infections in pets in France was low (1.8%), but most isolates (87.0%, 20/23) belonged to human clones. The most common clones were the Lyon clone (69.6%, 16/23), the livestock-associated CC398 (13.0%, 3/23) and the Geraldine clone (8.7%, 2/23). Interestingly, we report the first USA300 clone infecting a European dog, which was probably imported by a US patient. CONCLUSIONS: Over a 5 year period, the proportion of MRSA infections in pets appears low (<2%) in France, but the distribution of the clones mostly mirrors the epidemiology of human invasive clones. These data highlight the role of pets as both victims and reservoirs of endemic, epidemic and/or invasive MRSA.

Anaplasmosis in two dogs in France and molecular and phylogenetic characterization of Anaplasma phagocytophilum.

Two dogs in France were diagnosed with Anaplasma phagocytophilum infection by real-time PCR. The most remarkable hematologic and biochemical findings were severe thrombocytopenia, mild neutrophilia, morulae in neutrophils, and increased serum concentration of the α2-globulin fraction detected by agarose gel electrophoresis of serum proteins. Using sequencing of the partial 16S rRNA and ankA genes, molecular characterization of the A. phagocytophilum strains showed that the organisms from both dogs were identical to the European strains isolated from horses and people. Based on phylogenetic analysis, the ankA gene was more discriminating than the 16S rRNA gene in distinguishing the majority of European and American strains of A. phagocytophilum infecting people and animals. Three isolates of A. phagocytophilum, 1 from Spain (cow) and 2 from Norway (sheep and deer), were external to the European and American clades.

Ralstonia pickettii-induced ataxia in immunodeficient mice.

We report here the characterization of an asymmetric ataxia syndrome (head tilt and circling, with death in the most severe cases) demonstrated by profoundly immunodeficient mice housed at the Institut Curie SPF facility. The immune system of the affected mice had been genetically modified so that they were deficient in both B and T cells. Extensive bacteriologic, parasitic, serologic, and histopathologic analysis of the affected animals and their healthy controls led us to identify Ralstonia pickettii as the causative agent of the ataxic syndrome. The outbreak was managed through a test-and-cull process. Even though they also carried Ralstonia pickettii, immunocompetent mice that were kept in the same facility, did not show any of the signs that were expressed by their immunodeficient counterparts. This case highlights the difficulty of maintaining immunocompetent and immunodeficient mice in the same microbiologic unit and the importance of enlarging the spectrum of health monitoring to opportunistic agents when investigating clinical cases in populations of immunocompromised rodents.

Effect of repeated freeze-thaw cycles on routine plasma biochemical constituents in canine plasma.

BACKGROUND: The effect of repeated freeze-thaw cycles on plasma constituents has not been assessed in dogs, although such a procedure is not uncommon to use in routine laboratory practice. OBJECTIVE: To assess the effect of freeze-thaw cycles on routine plasma constituents in healthy dogs. METHODS: Six healthy adult dogs were used. Blood was sampled and placed in heparinized tubes. After centrifugation, plasma was separated into 5 aliquots. One aliquot was considered as the reference aliquot and used immediately for the assay of all of the biochemical constituents. All of the other aliquots were stored at 20 degrees C. Three aliquots underwent 1, 2, or 3 freeze-thaw cycles during a 1- to 3-day period. The last aliquot remained at 20 degrees C throughout the study and was thawed on the third day. The following biochemical constituents were assayed: glucose, urea, creatinine, total proteins, sodium, potassium, chloride, calcium, phosphates, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), and alkaline phosphatase (ALP). RESULTS: No clinically relevant change was observed between the different aliquots for all of the constituents. CONCLUSION: Repeated freeze-thaw cycles do not cause changes in the biochemical constituents studied in canine plasma.

In vitro antimicrobial activity of orbifloxacin against Staphylococcus intermedius isolates from canine skin and ear infections.

The objective of the study was to evaluate the in vitro activity of orbifloxacin against Staphylococcus intermedius strains isolated in France from canine skin and ear infections. The minimum inhibitory concentrations (MICs) of orbifloxacin against 240 field S. intermedius isolates (69 skin and 171 ear isolates) ranged from 0.016 to 8 mg l(-1), with MIC50 and MIC90 equal to 0.5 and 1 mg l(-1), respectively. Only one strain, a pyoderma isolate was resistant (MIC=8 mg l(-1)). Orbifloxacin was tested at different concentrations for killing rate against five isolates obtained from pyoderma cases and against a reference strain (Staphylococcus aureus ATCC 29213). Orbifloxacin expressed a concentration-dependent bactericidal activity against the S. aureus reference strain, but a time-dependent bactericidal activity against S. intermedius. Orbifloxacin induced bactericidal effect against the S. intermedius strains tested with concentrations equal to or two times MIC.