NAME: Actinobacillus spp. and Aggregatibacter spp.
SYNONYM OR CROSS REFERENCE: Actinobacillus spp: Actinobacillus lignieresii, Actinobacillus ureae (formerly Pasteurella ureae), Actinobacillus hominis, Actinobacillus suis actinobacillosis (1-4); Aggregatibacter spp. (formerly Actinobacillus and Haemophilus species), Aggregatibacter actinomycetemcomitans (formerly Actinobacillus actinomycetcomitans), Aggregatibacter aphrophilus (formerly Haemophilus aphophilus) and Aggregatibacter segnis (formerly Haemophilus segnis) (4, 5)
CHARACTERISTICS: Actinobacillus and Aggregatibacter spp. both belong to the family Pasteurellaceae (1). They are facultative anaerobic, non-motile, non-spore-forming, coccoid to small gram negative rods (mean size 0.1 – 1.0 um) (1, 3). They have what is described as a Morse-code appearance and irregular staining (3). The colonies are translucent and 1-2 mm in diameter on blood agar (3). Growth requires enriched media and is improved by a 5 % - 10 % CO2 atmosphere (1). Aggregatibacter spp. are as for Actinobacillus, except that some strains may require V factor (that is, NAD or NADP) for growth but no strain in either genus requires X factor (heme).
PATHOGENICITY/TOXICITY: Aggregatibacter actinomycetemcomitans, Actinobacillus. ureae, and A. hominis exclusively colonize humans (1). The other Actinobacillus species colonize animals, which can act as a reservoir for opportunistic human infections. A. actinomycetemcomitans is part of the normal flora of the human oral cavity and is one of the major causes of endocarditis, soft tissue infections, abscess formation, and adult and juvenile periodontis (1, 3). A. ureae and A. hominis have primarily been found in the sputum and tracheal secretions in patients with chronic respiratory tract diseases or pneumonia, although systemic infections have been reported (1). It is assumed that they also colonize the respiratory tract of healthy individuals. A. lignieresii causes actinobacillosis, a granulomatous disease in cattle and sheep. A few human soft tissue infections, originating from contact with, or bites from, cattle or sheep have been reported. A. equuli and A. suis cause a variety of diseases in horses and pigs and human infection are mostly due to horse or pig bites. Both species have also been isolated from the human upper respiratory tract. A. pleuropneumoniae causes porcine pleuropneumonia, a highly contagious and often fatal respiratory disease of major economic importance to the pig industry (2). The disease, which occurs in pigs of all ages, is characterized by necrotizing, haemorrhagic bronchopneumonia and serofibrinous pleuritis.
EPIDEMIOLOGY: Worldwide distribution. Aggregatibacter actinomycetemcomitans is commonly found in Asian populations and several studies showed a clear predominance of serotype c in Japanese, Chinese, Vietnamese, and Korean individuals (6). Conversely, the JP2 clone of A. actinomycetemcomitans has enhanced virulence and causes significantly higher prevalence of aggressive periodontitis in adolescents whose descent can be traced back to the Mediterranean and Western parts of Africa(6).
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: Aggregatibacter actinomycetecmcomitans can be transmitted to humans from animal bites (sheep, pigs, horses, cattle) (1, 2, 6) or between humans via direct contact with human saliva (9, 10).
INCUBATION PERIOD: Unknown.
COMMUNICABILITY: Capable of transmission from person-to-person. Studies demonstrate that family members commonly harbour the same strain of A. actinomycetemcomitans (10).
ZOONOSIS: Capable of zoonosis. Actinobacillus or Aggregatibacter spp. can be transferred to humans by animal bites (1).
DRUG SUSCEPTIBILITY/RESISTANCE: Actinobacillus or Aggregatibacter strains are generally susceptible to a range of antibiotics, including cephalosporins, cefotaxime, cefazolin, doxycycline and aminoglycosides (1, 3).
DRUG RESISTANCE: Aggregatibacte. actinomycetemcomitans is resistant to penicillin and macrolides (1, 3). A. lignieresii is sensitive to chloramphenicol, chlortetracycline, oxytetracycline and streptomycin, and resistant to neomycin, novobiocin and oleandomycin (3).
SUSCEPTIBILITY TO DISINFECTANTS: Generally susceptible to glutaraldehyde, sodium hypochlorite, hydrogen peroxide and sulfathiazole (11, 12). A. pleuropneumoniae has been shown to also be susceptible to mercurochrome, high concentrations of iodine, and a quaternary ammonium compound formulation containing combinations of benzalkonium chloride, glutaraldehyde, glyoxal and formaldehyde (12).
PHYSICAL INACTIVATION: Heat at 121 °C for 15 minutes under pressure. Specific species may be heat inactivated at lower temperatures (3).
SURVIVAL OUTSIDE HOST: Survives less than 24 hours when dried on paper (3).
SURVEILLANCE: Monitor for symptoms. Infection can be confirmed by bacterial isolation on enriched growth media such as blood agar with appropriate supplements followed by morphological assessment and biochemical testing (i.e. PCR for surface polysaccharides, immunofluorescence) (1, 3).
Note: All diagnostic methods are not necessarily available in all countries.
LABORATORY ACQUIRED INFECTIONS: None reported to date.
SOURCES/SPECIMENS: Human and animal samples: tracheal secretions, bronchial washings and lavages, oral cavity samples (subgingival plaque samples, dental plaque samples), pus and exudates from lesions, blood, cerebrospinal fluid, respiratory tract samples (1, 3).
PRIMARY HAZARD: Accidental parenteral inoculation or mucous membrane exposure.
SPECIAL HAZARD: None.
RISK GROUP CLASSIFICATION: Risk group 2 (13). This risk group applies to the genus as a whole, and may not apply to every species within the genus.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures. These containment requirements apply to the Actinobacillus spp. as a whole, and may not apply to each species within the genus.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes (14).
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited (14). Additional precautions should be considered with work involving animals or large scale activities.
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover the spill with absorbent paper towel and apply suitable disinfectant, starting at the perimeter and working towards the centre; allow sufficient contact time before clean up (14, 15).
DISPOSAL: Decontaminate all wastes before disposal; steam sterilization, chemical disinfection, incineration (14).
STORAGE: In sealed containers that are appropriately labelled (14).
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: August 2010
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2010