Other aero-anaerobic gram-negative bacilli


Bacteria cited herein are present in the oral flora of animals and can be found in wounds or when consecutive septicemia bites. These are small Gram-negative bacilli, motionless, giving small colonies that grow slowly on blood agar or chocolate agar incubated in an atmosphere enriched in CO ^.

Not yet classified accurately, the bacilli are appointed by the CDC as: EF Group 4 (eugonic ferment); Group M 5;Group II; (Related to Flavobacterium) and DF Group 2 (dysgonic ferment, now classified as Capnocytophaga canimorsus). The characters that distinguish P. multocida are presented in the table below.

Streptobacillus moniliformis:

This bacterium has no taxonomic relationship with Pasteurella. This is because the infection generally follows a bite as we situate here.


Gram-negative bacillus, forming long, flexuous filaments, but also giving coccobacillary forms. In older cultures the few days Gram stain can be positive.

The culture is done in aero-anaerobic, it is favored by a CO2-enriched atmosphere. This germ requires blood, serum or ascites. The colonies develop in 2 to 5 days.

Sodium sulfate polyethanol (SPS), anticoagulant used in blood culture bottles, has an inhibitory effect. It is necessary in case of suspicion of infection with S. moniliformis use blood culture bottles containing citrate as anticoagulant.


Commensal of the oral cavity of rodents.


– Sepsis occurring 3 to 5 days after a rat bite. Joint effusions are common and allow the isolation of the germ. These septicemia may be complicated by endocarditis, pericarditis, cerebral abscess.

– The rodent droppings may be contaminants and not preceded bite infections have been described.


S. moniliformis is sensitive to most antibiotics including penicillin G to which this organism is very sensitive.


Common characters

Gram-negative bacilli, motionless, oxidase positive, catalase positive, growing on blood agar giving small colonies, are not developing or poorly MacConkey agar. The LOC is negative.

Other aero-anaerobic gram-negative bacilli


The bacillus of cat scratch disease was described in 1988 and assigned to the genus Afipia (the AFIP acronym for Armed Forces Institute of Pathology in Washington, DC, USA where the first strain was isolated). These are Gram-negative bacilli, oxidase positive, mobile, growing on BCYE agar (see Legionella) and nutrient broth at 25 and 30 ° C, but not on Mac Conkey. The colonies are greyish, shiny, convex, with sharp edges. The character is urease positive, but hemolysis, indole production, SH2, hydrolysis of gelatin and esculin is negative; there is no oxidation of the glucose, lactose, maltose and sucrose.

The species felis Afipia is responsible for cat scratch disease was isolated from an affected individual ganglion. A.felis is resistant to many antibiotics and is sensitive to aminoglycosides, imipenem and ceftriaxone. The other species of the genus, A. clevelandensis, A. broomae and A. genospecies 1,2 and 3 are not associated with cat scratch disease and have been isolated from wounds, sputum, synovial fluid, pleural fluid, bronchial lavage fluid and water.