Serum procalcitonin as a diagnostic biomarker in dogs with bacterial respiratory diseases.

BACKGROUND: Procalcitonin (PCT) is a useful biomarker in humans in the identification of bacterial respiratory infections. OBJECTIVES: The aim of this study was to investigate the utility of serum PCT measurements as a diagnostic biomarker in canine bacterial lower respiratory tract diseases. METHODS: PCT concentrations were measured in serum samples with an ELISA method previously validated for dogs. All dogs underwent thorough clinical examinations, and the diagnosis of respiratory disease was based on clinical and laboratory findings, diagnostic imaging, as well as cytology and bacterial culture of respiratory samples. PCT concentrations between different cohorts of dogs were compared with an ANOVA-model. RESULTS: Sixty-two privately owned dogs with respiratory diseases, 25 with bacterial pneumonia (BP), 17 with bacterial bronchitis caused by Bordetella bronchiseptica (BB), and 20 with chronic bronchitis (CB) as well as 44 healthy controls were included in the study. Serum PCT concentrations in dogs with bacterial respiratory diseases (BP mean 51.8 ng/L ± standard deviation [SD] 40.6 ng/L and BB mean 61.4 ng/L ± SD 35.3 ng/L) were not significantly different when compared with dogs with a non-bacterial respiratory disease (CB mean 89.7 ± SD 73.5 ng/L) or healthy dogs (mean 51.0 ng/L ± SD 37.5 ng/L, p > .05 in all comparisons). CONCLUSIONS: These results indicate that despite being a valuable diagnostic, prognostic, and follow-up marker in humans with pneumonia, serum PCT concentrations are not elevated in dogs with bacterial respiratory diseases and, therefore, cannot be used as a diagnostic biomarker in dogs.

The Utility of Acute-Phase Proteins in the Assessment of Treatment Response in Dogs With Bacterial Pneumonia.

BACKGROUND: Acute-phase proteins (APPs) are sensitive markers of inflammation, and serum C-reactive protein (CRP) recently has been shown to be a useful diagnostic marker in dogs with bacterial pneumonia (BP). In humans with community-acquired pneumonia, APPs also have great utility as follow-up markers aiding in the assessment of treatment response. OBJECTIVES: The aim of our study was to investigate the applicability of APPs as markers of treatment response in dogs with BP. ANIMALS: Nineteen dogs diagnosed with BP and 64 healthy dogs. METHODS: The study was conducted as a prospective longitudinal observational study. Serum CRP, serum amyloid A (SAA), and haptoglobin concentrations were followed during a natural course of BP. Normalization of serum CRP was used to guide the duration of antibiotic treatment (treatment was stopped 5-7 days after CRP normalized) in 8 of 17 dogs surviving to discharge; 9 of 17 dogs were treated according to conventional recommendations. RESULTS: All measured APPs initially were significantly increased, but the magnitude of increase was not correlated to disease severity. C-reactive protein and SAA concentrations decreased rapidly after initiation of antimicrobial treatment. When normalization of serum CRP was used to guide the duration of antibiotic treatment, treatment duration was significantly (P = .015) decreased without increasing the number of relapses. CONCLUSIONS AND CLINICAL IMPORTANCE: Serum CRP and SAA reflected the recovery process well and therefore may be used as markers of treatment response. According to the results, the normalization of serum CRP may be used to guide the duration of antibiotic treatment in dogs with BP.

Co-infections with respiratory viruses in dogs with bacterial pneumonia.

BACKGROUND: Bacterial pneumonia (BP) is an inflammation of the lower airways and lung parenchyma secondary to bacterial infection. The pathogenesis of BP in dogs is complex and the role of canine respiratory viruses has not been fully evaluated. OBJECTIVES: The aim of this study was to investigate the occurrence of viral co-infections in dogs with BP and to assess demographic or clinical variables as well as disease severity associated with viral co-infections. ANIMALS: Twenty household dogs with BP caused by opportunistic bacteria and 13 dogs with chronic (>30 days) tracheobronchitis caused by Bordetella bronchiseptica (BBTB). METHODS: Prospective cross-sectional observational study. Diagnosis was confirmed by clinical and laboratory findings, diagnostic imaging, and cytologic and microbiologic analysis of bronchoalveolar lavage or transtracheal wash fluid. Canine parainfluenza virus (CPIV), canine adenovirus, canine herpes virus, canine influenzavirus, canine distemper virus, canine respiratory coronavirus (CRCoV) and canine pneumovirus, as well as B. bronchiseptica and Mycoplasma spp. were analyzed in respiratory samples using PCR assays. RESULTS: CPIV was detected in 7/20 and CRCoV in 1/20 dogs with BP. Respiratory viruses were not detected in dogs with BBTB. There were no significant differences in clinical variables between BP dogs with and without a viral co-infection. CONCLUSION AND CLINICAL IMPORTANCE: Respiratory viruses were found frequently in dogs with BP and may therefore play an important role in the etiology and pathogenesis of BP. Clinical variables and disease severity did not differ between BP dogs with and without viral co-infection.

Serum C-reactive protein as a diagnostic biomarker in dogs with bacterial respiratory diseases.

BACKGROUND: C-reactive protein (CRP) is a major acute-phase protein in dogs. Serum concentrations are low in healthy animals, but increase rapidly after inflammatory stimuli. OBJECTIVE: The aim of the study was to investigate CRP concentrations in various respiratory diseases of dogs and to determine if CRP can be used as a biomarker in the diagnosis of bacterial respiratory diseases. ANIMALS: A total of 106 privately owned dogs with respiratory diseases (17 with bacterial tracheobronchitis [BTB], 20 with chronic bronchitis [CB], 20 with eosinophilic bronchopneumopathy [EBP], 12 with canine idiopathic pulmonary fibrosis [CIPF], 15 with cardiogenic pulmonary edema [CPE], and 22 with bacterial pneumonia [BP]) and 72 healthy controls. METHODS: The study was conducted as a prospective cross-sectional observational study. CRP was measured in serum samples. Diagnosis was confirmed by clinical and laboratory findings, diagnostic imaging, and selected diagnostic methods such as cytological and microbiological analysis of respiratory samples, echocardiography, and histopathology. RESULTS: Dogs with BP had significantly higher CRP concentrations (median, 121 mg/L; interquartile range, 68-178 mg/L) than dogs with BTB (23, 15-38, P = .0003), CB (13, 8-14, P < .0001), EBP (5, 5-15, P < .0001), CIPF (17, 10-20, P < .0001), or CPE (19, 13-32, P < .0001) and healthy controls (14, 8-20, P < .0001). Dogs with BTB had significantly higher CRP concentrations than dogs with CB (P = .001) or EBP (P < .0001) and healthy controls (P = .029). CONCLUSION AND CLINICAL IMPORTANCE: These results indicate that CRP has potential for use as an additional biomarker, especially in the diagnostics of BP.