Pasteurella spp. (Pasteurella multocida subsp. multocida and other species) - Culture; Molecular diagnosis (PCR).

Information 28-02-2015.

Pasteurella multocida is a Gram - negative, small, motionless cocobacillus that usually shows bipolar staining with some stains (Giemsa or their equivalents, methylene blue). It can be seen isolated, in pairs or short chains. Lacks nutritional needs, is well developed at 37 ° C on blood agar 5% chocolate agar, Mueller-Hinton agar, heart infusion agar-brain (BHI), but that does not grow on MacConkey medium. Aerobic-anaerobic facultative, catalase +, oxidase +, indole + ODC +, ferments glucose, sucrose and maltose. Usually a commensal to be accompanied by other bacteria, and also accompanied by other bacteria infections known a selective culture medium incorporating any antimicrobial as vancomycin, clindamycin, gentamicin, neomycin, kanamycin or amikacin may be used. Classical microbiological methods, for easy isolation, resort to perform an enrichment culture in broth for 4 hours, and then inoculate a mouse intraperitoneally, and when the mouse died (when there was Pasteurella in the sample), taking blood heart and proceed to plating. The identification problem is differentiated from other bacteria of the same family (Pasteurellaceae) as are other species of Pasteurella, Haemophilus spp., Mannheimia spp., Actinobacillus spp., Avibacterium spp., Etc. They can differentiate several capsular types (5 types) as its antigenicity. Capsule Type A is composed of hyaluronic acid; type B arabinose, mannose and galactose; Heparin type D; type E is characterized its component; and F type chondroitin. 16 also differentiated serovars lipopolysaccharide (LPS). The combination of both types, capsular and lipopolysaccharide can speak of types A 1, A 2, A 3, etc. The frequency with which it is present in colonization and infection accompanied by other bacteria, detection by amplification of 16S rRNA gene or its gene encoding the toxin is very useful. Furthermore , this same method can differentiate it from other species of Pasteurella, or other species from other genera of the same family Pasteurellaceae.
Pasteurella multocida has the following virulence factors: capsule (types A to F); fimbriae adhesion receptors N-acetyl-D-glucosamine; -OMP- outer membrane protein which is hemoglobin binding protein (HgbA) with three different types (I, II and III); lipopolysaccharide serotypes 16; one dermonecrotic exotoxin (DNT); a chelating iron siderophore (multocidina); several extracellular enzymes (lipase, hyaluronidase); and plasmids antibiotic resistance and production of toxin.
Pasteurellaceae within the family, which has been introduced taxonomic changes have changed some species to other genres, Pasteurella not only gender, but also in other genera of the same family, as indicated below:
Pasteurella haemolytica -> Mannheimia haemolytica.
Pasteurella trehalosi -> Bibersteinia trehalosi.
Pasteurella gallinarum -> Avibacterium gallinarum.
Pasteurella avium -> Avibacterium avium.
Pasteurella ureae -> Actinobacillus ureae.
Pasteurella anatis -> Gallibacterium anatis.
Actinobacillus actinomycetemcomitans -> Aggegatibacterium actinomycetemcomitans.
Haemophilus aphrophilus -> Agregatibacterium aphrophilus.
Haemophilus plauropneumoniae -> Actinobacillus pleuropneumoniae.
Mannheimia succiciproducens -> Basfia succiniproducens.
Haemophilus paragallinarum -> Avibacterium paragallinarum.
Haemoiphilus somnus -> H. somni.
P. aerogenes, P. bettyae, P. caballi, P. canis, P. dagmatis, P. multocida subsp: the following species of Pasteurella are currently supported. multocida, P. multocida subsp. gallicida, P. multocida subsp. septica, P. tigris, P. pneumotropica, P. stomatis, P. testudinis.
Pasteurella multocida, usually exists as a commensal in the upper respiratory tract of many domestic animals such as chickens, pets, primarily cats and dogs, and also in wild animals. Human infections are usually related to the bite, scratch or lick, but can also occur without contact with animals have. Infections from animals are frequently caused by cats after (60-80%), followed by dogs (50%) lesions. Infections with animal bites typically polymicrobial, so must be treated empirically with broad spectrum antimicrobials, both gram - negative aerobic and anaerobic. Infections usually cause inflammation of rapidly progressive soft tissue infections can remember beta-hemolytic Streptococcus pyogenes. Deep soft tissue infections, expressed as tenosynovitis, septic arthritis and osteomyelitis can occur. Sometimes more serious infections such as endocarditis or meningitis, which when they occur in children Haemophilus influenzae suggest or Neisseria meningitidis occur.
Persons at risk of being colonized by Pasteurella multocida, or infections have it are: pet owners, veterinarians, farmers, handlers livestock and meat food handlers.
The main types of infections that occur are:
Local infections: most of the time (60-80%), caused by scratch or bite of a cat, and other injuries caused by dogs. Local infection is characterized by rapid onset of erythema, warmth, induration, and often purulent drainage. The most common complication is the formation of an abscess, tenosynovitis, septic arthritis and the next joint to the bite or scratch. It can occur by direct inoculation osteomyelitis or extent of cellulite contiguous fingers after cat bites.
Respiratory infections: most often find a commensal in patients with underlying pulmonary disease but may cause serious infections such as pneumonia, empyema or lung abscess. Most settlements are related to regular contact or exposure to animals. It can cause upper respiratory infections, including sinusitis, otitis media, mastoiditis, epiglottitis, pharyngitis and Ludwig 's angina. In rare cases it can cause lower respiratory infections such as pneumonia, tracheobronchitis, lung abscess and empyema, generally in patients with underlying pulmonary disease, including chronic obstructive pulmonary disease.
Cardiovascular described cases of prosthetic valve endocarditis, pericarditis, mycotic aneurysms, vascular graft infections, infections of central venous catheters, bacteremia, sepsis, and septic shock and disseminated intravascular coagulation. The existence of diabetes may be a predisposing factor for bacteremia.
Central nervous system: rare cause of meningitis, subdural empyema, brain abscess. Meningitis have been linked to licking cats and bites on the face of the elderly.
Gastrointestinal disturbances : rarely have been described cases appendicitis, hepatosplenic abscesses, spontaneous bacterial peritonitis and.
Eyepieces: periocular abscess, conjunctivitis, corneal ulcers and endophthalmitis.
Genitourinary: pyelonephritis, renal abscess, epididymitis, cervicitis.
In animals can cause endemic diseases or epizootic in a large number of species of domestic and wild animals, including birds. It is a common commensal or opportunistic upper respiratory tract of farm animals, domestic or wild, as chickens, turkeys, wild fowl, cattle, pigs, rabbits, dogs and cats or other felines. It produces mild or asymptomatic infections or upper respiratory inflammatory pneumonic acute infections or scattered, often fatal. Transmission between animals occurs by direct contact through nasal secretions. The prior existence of other pathogens or coinfection with other respiratory pathogens such as Mannheimia haemolytica or Bordetella pertussis, or mycoplasma respiratory virus promotes their infection. It has been associated with atrophic rhinitis corresponding to a syndrome, mild or severe, with sneezing, mucous secretion, moderate rhinitis, mild pneumonia, fever upper respiratory disease (rhinitis) and respiratory infections lower (pneumonia) which may progress to septicemia ( haemorrhagic septicemia) and / or atrophic rhinitis.
antimicrobial treatment

Most infections respond to treatment with amoxicillin, amoxicillin-clavulanate, minocycline, trimethoprim-sulfamethoxazole or fluoroquinolone. Pasteurella multocida is resistant isoxazolilpenicilinas (cloxacillin), first generation cephalosporins (cephalexin, cefaclor, cefadroxil), lincosamides (clindamycin), macrolides (erythromycin), aminoglycosides (gentamicin, amikacin), and glycopeptides (vancomycin).

Described strains producing beta-lactamases. For severe infections, ampicillin-sulbactam, piperacillin-tazobactam, cefoxitin, or carbapenem it is recommended, since in infections bites should cover gram - positive bacteria, Gram - negative and anaerobic. Tigecycline also has excellent activity. If there is only Pasteurella multocida, it may be treated with penicillin G intravenously. Once you have improved it can be administered an oral penicillin (penicillin V). In allergic penicillin tetracycline (minocycline, doxycycline), a fluoroquinolone (ciprofloxacin, levofloxacin), trimethoprim-sulfametoixazol, or azithromycin is recommended.

By frequent associations with other bacteria, some of the following associations are recommended: amoxicillin-clavulanate; Doxycycline with metronidazole (in allergic penicillins); fluoroquinolone associated clindamycin, trimethoprim-sulfamethoxazole or, in pregnant or ceftriaxone.

microbiological diagnosis

  • Microscopic examination: Gram stain and Giemsa exudates purulent, sputum, cerebrospinal fluid can detect the presence of small coccobacilli pleomorphic, gramnegative. Some bacteria such as Haemophilus spp., Moraxella spp., Acinetobacter spp and., May have similar morphologies. With Giemsa (or their equivalents as Wright or Wayson) or methylene blue, you can best express the bipolar staining. In some strains can be demonstrated in the capsule staining.

  • Cropping infections animal bites typically polymicrobial, with aerobic and anaerobic bacteria. Can be found several subspecies of Pasteurella; Pasteurella multocida subsp. multocida, Pasteurella multocida subsp. tank, Pasteurella stomatis, dagmatis Pasteurella, Pasteurella canis or. Other related bacteria including animal bites Capnocytophaga canimorsus (which can cause fulminant sepsis and meningitis), and Capnocytophaga cynodegmi (moderate local inflammation). With cat bites found Francisella tularensis and Bartonella henselae and cowpoxvirus.

  • Antimicrobial sensitivity: high sensitivity to penicillins and cephalosporins, tetracyclines, fluoroquinolones and. Penicillins resistant strains have been isolated from respiratory infections.

Tests in IVAMI:

  • Microscopic examination by Giemsa or Gram.
  • Growing samples from respiratory secretion (preferred) or other mucosal colonization to detect in humans or animals, or purulent samples infected lesions.
  • Antimicrobial susceptibility: susceptibility testing antimicrobial usual.
  • Molecular diagnosis (PCR): this test provides the advantage of detecting its presence without identification in cultures typically polymicrobial.

Recommended sample:

  • Exudates skin infectious lesions: Swab sterile dacron / rayon shank aluminum or plastic impregnated with injury or aspirate the lesion dispensing a preferably sterile tube sealing, polypropylene to prevent breakage during transportation to the laboratory) .
  • Samples of animals: respiratory swab taken swab.
  • Upper respiratory disease: exudate sample taken swab.
  • Arthritis (synovial fluid): depositing 1 to 2 mL of liquid sample in a tube or in a sterile container, preferably polypropylene to prevent breakage, containing 3 mL of a universal transport medium.
  • Deep breathing exudates deposited in sealed, sterile container polypropylene preferable to avoid breakage during transport to the laboratory.
  • Central nervous system: cerebrospinal fluid sample, 2 mL in sterile polypropylene vial.
  • Other signs: According presentation.

Preservation and shipment of sample:

Refrigerated (preferred) for less than 2 days.
Frozen: over 2 days.

Cost of the test: