A systematic review and meta-analyses of the association between 4 mycoplasma species and lower respiratory tract disease in dogs

BACKGROUND

The pathogenic role of mycoplasmas in the lower respiratory tract (LRT) of dogs is debated, because mycoplasmas can be isolated from both healthy and sick dogs.

OBJECTIVES

To critically assess available data from controlled observational studies on the role of 4 mycoplasma species in LRT disease of dogs.

DESIGN

Systematic review and meta-analyses.

METHODS

Seven electronic databases were searched for relevant publications. Risk of bias was assessed by the Newcastle-Ottawa Scale. Meta-analyses, stratified by mycoplasmal species, were performed using a random effects Bayesian model with noninformative priors to estimate pooled odds ratios (ORs) and 95% confidence intervals (CIs) for the association between Mycoplasma cynos, Mycoplasma canis, Mycoplasma spumans, and Mycoplasma edwardii and LRT disease in dogs.

RESULTS

Five studies were included from 1201 references identified. All studies dealt with M. cynos, whereas 3 dealt with the other mycoplasma species. A significant association was found between M. cynos and LRT disease (Bayesian OR, 3.60; CI, 1.31-10.29). Conversely, M. canis, M. spumans, and M. edwardii were not significantly associated with LRT signs (Bayesian OR, 1.06; CI, 0.10-14.63; Bayesian OR, 3.40; CI, 0.16-54.27; and Bayesian OR, 1.04; CI, 0.05-23.54, respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Results support a pathogenic role of M. cynos and a commensal role of M. canis and M. edwardii in LRT in dogs. Although the association was not significant based on the CI, the point estimate of the Bayesian OR was relatively high for M. spumans, making its role less clear. Mycoplasma cynos-specific polymerase chain reaction should be considered on samples from dogs with LRT.

A novel quantitative polymerase chain reaction to monitor urinary tract mycoplasma infection in a dog

The aim of the study was to develop a quantitative real-time PCR assay for diagnosis and monitoring of mycoplasma urinary tract infections (UTI) in a dog. An English Cocker Spaniel dog with the history of urinary tract infection was physically examined and laboratory findings identified chronic renal insufficiency and urinary tract infection. Attempts to culture organisms from pyuric urine failed, and empirical antibiotic therapy did not resolve the pyuria. A mycoplasma species most closely resembling Ureaplasma canigenitalium was identified in urine samples by conventional PCR and sequencing. A quantitative PCR method was developed to monitor and finally verify successful treatment. This novel approach to monitoring mycoplasma urinary tract infections is conceptually simple, and provides rapid results. It may have wider application in monitoring treatment efficacy for infections with other Mycoplasma spp. as well as additional organisms that are difficult to culture. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we highlight two different findings, detection of Ureaplasma canigenitalium in a dog with chronic urinary tract infection and development of a quantitative real-time PCR test to track treatment results in an infected dog. This report is the first report of detection of U. canigenitalium in one dog in Australia. This novel qPCR method for monitoring mycoplasma urinary tract infections is conceptually simple and provides results fast. It will have wider applications in monitoring treatment efficacy for infections with mycoplasmas and mycoplasma-like organisms that are difficult to culture, and provides a sensitive guide to treatment progress.

Detection of specific bacterial agents by quantitative PCR assays in the bronchoalveolar lavage fluid of dogs with eosinophilic bronchopneumopathy vs. dogs with chronic bronchitis and healthy dogs

In humans, Mycoplasma pneumoniae and Bordetella pertussis infections are suggested to trigger or exacerbate asthma. Whether Mycoplasma or Bordetella are associated with chronic inflammatory bronchial diseases in dogs has not been investigated. The aim of this study was to assess detection rates of Mycoplasma canis (M. canis), M. cynos and Bordetella bronchiseptica (Bb), in dogs with eosinophilic bronchopneumopathy (EBP) and chronic bronchitis (CB), compared with healthy dogs. Specific quantitative PCR (qPCR) analysis for M. canis, M. cynos and Bb were retrospectively performed on bronchoalveolar lavage fluid (BALF) collected from 24 dogs with EBP, 21 dogs with CB and 15 healthy dogs. Possible associations between qPCR results and age, BALF cytology or clinical severity scores (CSS) in dogs with EBP were investigated. There was no difference in M. canis, M. cynos and Bb detection rates in dogs with EBP (n=6, n=2 and n=6, respectively) and dogs with CB (n=2, n=2 and n=2, respectively) compared with control dogs (n=4, n=2 and n=2, respectively). In dogs with EBP, the proportion that were qPCR-positive for Bb was higher in dogs with higher CSS (P=0.014) and BALF from Bb-positive dogs had higher percentage of neutrophils (P<0.001). Among dogs that were qPCR-positive for Bb, moderate to high loads were only detected in dogs with EBP. M. canis and M. cynos detection was not associated with EBP or CB; higher Bb loads were only present in dogs with EBP and high CSS. A possible cause and effect relationship between Bb infection or load and EBP remains unclear and requires further investigation.

Quantitative PCR and Cytology of Bronchoalveolar Lavage Fluid in Dogs with Bordetella bronchiseptica Infection

Background

The use of quantitative PCR (qPCR) for detection of Bordetella bronchiseptica in bronchoalveolar lavage fluid (BALF) and demonstration of bacteria adhering to ciliated epithelial cells in BALF or bronchial brushing fluid (BBF) has not been assessed in a series of affected dogs. Coinfections can worsen the clinical severity in bordetellosis, but the specific association with Mycoplasma cynos has not been evaluated.

Objectives

To assess the utility of culture, qPCR and cytologic examination of cytospin preparations in the diagnosis of bordetellosis in dogs and the influence of coinfection by M. cynos on disease severity.

Animals

Twenty‐four referred dogs with B. bronchiseptica infection and 10 healthy dogs.

Methods

Retrospective case series. qPCR (B. bronchiseptica and M. cynos) and culture results from BALF were recorded. Cytospin preparations from BALF and BBF were reviewed. qPCR on BALF from 10 healthy dogs were used as negative control.

Results

The BALF culture and qPCR detected B. bronchiseptica in 14/24 and 18/18 dogs, respectively. Coccobacilli were found adhering to ciliated epithelial cells in 20 of the 21 BALF cytologic preparations where epithelial cells were found, and 2/3 BBF cytologic preparations. Quantitative PCR detected a low level of B. bronchiseptica in one healthy dog. The frequency of detection of M. cynos was not significantly different in B. bronchiseptica (9/17 dogs) compared with healthy dogs (2/10 dogs) (P = .09).

Conclusion and Clinical Importance

Quantitative PCR detection of B. bronchiseptica in BALF appears to be a useful diagnostic tool. Cytologic examination of BALF or BBF, when positive, allows a rapid and reliable diagnosis.

Antimicrobial use Guidelines for Treatment of Respiratory Tract Disease in Dogs and Cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases

Respiratory tract disease can be associated with primary or secondary bacterial infections in dogs and cats and is a common reason for use and potential misuse, improper use, and overuse of antimicrobials. There is a lack of comprehensive treatment guidelines such as those that are available for human medicine. Accordingly, the International Society for Companion Animal Infectious Diseases convened a Working Group of clinical microbiologists, pharmacologists, and internists to share experiences, examine scientific data, review clinical trials, and develop these guidelines to assist veterinarians in making antimicrobial treatment choices for use in the management of bacterial respiratory diseases in dogs and cats.