Bacterial diseases

From Dog

The vast majority of non-traumatic diseases in dogs are caused by bacteria or their secondary involvement in the disease process.

Three broad groups of bacteria exist, defined by their ability to uptake Gram stain, which defines the presence of a peptidoglycan cell wall. This is important, primarily, with choice of antimicrobial therapy.

  • Gram-positive bacteria - peptidoglycan cell wall
  • Gram-negative bacteria - lipopolysaccharide membrane
  • Proteobacteria are all Gram-negative, with an outer membrane mainly composed of lipopolysaccharides. Many move about using flagella, but some are nonmotile or rely on bacterial gliding. The last include the myxobacteria, a unique group of bacteria that can aggregate to form multicellular fruiting bodies. There is also a wide variety in the types of metabolism. Most members are facultatively or obligately anaerobic, chemoautotrophs, and heterotrophic, but there are numerous exceptions[1].
  • Alphaproteobacteria - includes Wolbachia spp, Bartonella spp, Rickettsia spp, Brucella spp, Ehrlichia spp and Anaplasma spp[2]. These are obligate intracellular endosymbionts living within nematodes. The bacterial infection is passed from worm to worm transovarially; the organisms are in ovarian cells and hypodermal tissues of free-lving and parasitic nematodes. In free-living hosts, they are responsible for nitrogen fixation.

Bacteria, in general, can cause varying ranges of illness in dog from mild dermatitis to sepsis and death.

Appropriate antimicrobial therapy should be based on isolation and culture and sensitivity of causative bacteria.

Bacterial resistance, especially to pathogenic Salmonella spp, methicillin-resistant Staphylococcus aureus and extended spectrum β-lactamase-producing E. coli mirrors the growing bacterial resistance in human microbiology[3].

Common bacterial diseases in dogs include:

Species Classification Location in dogs Disease
Acinetobacter baumannii Gram -ve, aerobic proteobacteria GI tract diarrhea, endocarditis, zoonotic
Actinobacillus spp Gram -ve, anaerobic oropharynx gingivitis
Actinomyces spp Gram +ve, aerobic/anaerobic GI tract systemic infections
Aggregatibacter actinomycetemcomitans Gram -ve, anaerobic oropharynx gingivitis, bite wounds
Alcaligenes faecalis Gram -ve, aerobic proteobacteria reproductive/urinary tracts otitis externa, cystitis, nosocomial infections
Anaerobiospirillum spp Gram -ve, anaerobic GI tract ulcerative colitis
Anaplasma spp Gram -ve, proteobacteria blood anemia, tick-borne fever
Arcanobacterium spp Gram +ve, aerobic skin otitis externa
Arcobacter spp Gram -ve, microaerophilic GI tract nonpathogenic, zoonotic
Bacteroides spp Gram -ve, aerobic GI tract bacteremia
Bartonella spp Gram -ve, anaerobic proteobacteria blood systemic disease
Bifidobacterium spp Gram +ve, anaerobic GI tract preventative probiotic
Bordetella bronchiseptica Gram -ve, proteobacteria respiratory tract kennel cough
Borrelia burgdorferi Gram -ve, spirochaete blood anemia, tick-borne fever
Brachyspira spp Gram -ve, anaerobic spirochaete GI tract nonpathogenic
Brucella canis Gram -ve anaerobic proteobacteria blood
Burkholderia pseudomellei Gram -ve proteobacteria skin, GI & respiratory tract melioidosis
Comamonas testosteroni Gram -ve, anaerobic proteobacteria endosymbiont of Spirocerca lupi nonpathogenic
Campylobacter spp Gram -ve, microaerophilic GI tract secondary diarrhea
Capnocytophaga canimorsus Gram -ve, anaerobic oropharynx zoonotic (bite wounds to humans)
Chlamydophila spp Gram -ve, aerobic skin, respiratory tract conjunctivitis and, rarely, pneumonia
Chromobacterium violaceum Gram -ve anaerobic proteobacteria skin pneumonia, zoonotic
Citrobacter spp Gram -ve, aerobic GI tract, reproductive tract cystitis
Clostridium spp Gram +ve, anaerobic GI tract, skin diarrhea, tetanus
Corynebacterium spp Gram +ve, aerobic/anaerobic skin, GI, urinary and reproductive tracts cystitis, abscess
Coxiella burnetti Gram -ve, anaerobic respiratory tract zoonotic (Q fever)
Desulfomicrobium orale Gram -ve, anaerobic proteobacteria oropharynx periodontitis
Ehrlichia spp Gram -ve proteobacteria blood anemia
Eikenella corrodens Gram -ve, anaerobic oropharynx gingivitis
Enterobacter spp Gram -ve, anaerobic proteobacteria respiratory & urinary tract cystitis
Enterococcus spp Gram +ve, anaerobic gastrointestinal tract diarrhea, periodontitis, peritonitis, cystitis
Erysipelothrix rhusiopathiae Gram +ve, microaerophilic gastrointestinal tract septic arthritis
Escherichia spp Gram -ve, anaerobic GI, reproductive, urinary tracts diarrhea, pyometra, peritonitis, pneumonia
Flexispira spp Gram -ve, microaerophilic spirochaete GI tract gastritis
Francisella tularensis Gram -ve, aerobic oropharynx tularemia
Fusobacterium spp Gram -ve, anaerobic skin, GI tract periodontitis, cellulitis and pyothorax
Granulicatella spp Gram +ve, aerobic saliva nonpathogenic
Haemophilus spp Gram -ve, aerobic/anaerobic proteobacteria GI & respiratory tract cystitis, meningitis
Helicobacter spp Gram -ve, microaerophilic proteobacteria GI tract gastritis
Klebsiella spp Gram -ve proteobacteria respiratory tract pneumonia
Leptospira spp Gram -ve, aerobic spirochaete GI & urinary tract, blood leptospirosis, cystitis
Listeria monocytogenes Gram +ve, anaerobic GI tract tonsillitis, diarrhea
Mycobacterium spp Gram +ve, aerobic skin, GI & respiratory tract leprosy and TB
Mycoplasma spp Gram -ve, aerobic respiratory tract pneumonia, pyothorax
Neisseriaceae spp Gram -ve, aerobic proteobacteria respiratory tract pneumonia
Nocardia spp Gram +ve, aerobic oropharynx, wounds, respiratory tract granuloma, pneumonia, pyothorax
Odoribacter denticanis Gram -ve, anaerobic GI tract periodontitis
Pasteurella multocida Gram -ve, anaerobic skin zoonotic bite wounds
Peptostreptococcus spp Gram +ve, anaerobic skin, GI and genitourinary tracts pyothorax
Porphyromonas gingivalis Gram -ve, anaerobic GI tract periodontitis
Prevotella melaninogenicus Gram -ve, anaerobic GI tract bite-wound related osteomyelitis, gingivitis
Propionibacterium spp Gram +ve anaerobic skin pyothorax
Providencia stuartii Gram -ve, aerobic skin, urinary tract dermatitis, cystitis
Proteus spp Gram -ve, anaerobic proteobacteria skin, cystitis, paronychia and various other skin diseases
Pseudomonas spp Gram -ve, aerobic proteobacteria skin, GI and respiratory tracts pneumonia
Rhodococcus spp Gram +ve, aerobic skin, respiratory tract pyothorax, cellulitis and pyogranulomas
Rickettsia spp Gram -ve, anaerobic proteobacteria blood tick-borne fever
Salmonella spp Gram -ve, anaerobic proteobacteria GI tract food spoilage diarrhoea
Serratia marcescens Gram -ve, aerobic skin endocarditis, nosocomial infection
Shigella spp Gram -ve, anaerobic proteobacteria GI tract rare cause of diarrhoea
Staphylococcus spp Gram +ve, aerobic skin, GI & respiratory tract superficial and systemic infections
Stenotrophomonas maltophilia Gram -ve, aerobic proteobacteria skin, GI tract nosocomial infection, cystitis
Streptobacillus moniliformis Gram -ve, anaerobic oral cavity zoonotic, rat-bite fever
Streptococcus spp Gram +ve, aerobic skin, GI & respiratory tract superficial and systemic diseases
Tannerella forsythia Gram -ve, anaerobic oropharynx periodontitis, bite wounds
Treponema denticola Gram -ve, aerobic spirochaete GI tract periodontitis, zoonotic bite wounds
Trueperella pyogenes Gram +ve, anaerobic skin cystitis
Wolbachia spp Gram -ve anaerobic proteobacteria endosymbiont within D. immitis nonpathogenic
Yersinia pestis Gram -ve, anaerobic GI tract plague


  1. Wikipedia
  2. Bowman DD (2011) Introduction to the alpha-proteobacteria: Wolbachia and Bartonella, Rickettsia, Brucella, Ehrlichia, and Anaplasma. Top Companion Anim Med 26(4):173-177
  3. Murphy C et al (2009) Occurrence of antimicrobial resistant bacteria in healthy dogs and cats presented to private veterinary hospitals in southern Ontario: A preliminary study. Can Vet J 50(10):1047-1053