Virulence and its relationship with antibiotic resistance

Pathogenic islands: Certain DNA blocks inserted into the chromosome of most cram negative bacteria originated in pathogens found in plants. Virulence-antibiotic interactions: During the invasive phase, the bacterial cell covers itself with adhesins which facilitate its adherence to tissues . The bacterial cell produces a fibronectin which protects its defense syst ems. Antibiotics favor bacterial resistance by increasing the expression of surface adhesins and fibronectin production. Penicillin resistant pneumococci: Experimental models have demonstrated tha t mortality in mice and host resistance to pneumococcal infection are relat ed to the type of capsule and not to antibiotic resistance. Quorum sensing: The bacterial inoculum regulates the production of virulenc e factors in vivo via quorum sensing. This regulation can play an important role in Pseudomonas aeruginosa infections. Acinetobacter baumanni virulence: Long poorly understood, factors favoring A. baumanni virulence appear to result from bacterial production of IROMPs in the extracellular growth medium in response to iron depletion during the exponential growth phase. Presse Med 1998; 27:S31-3 (C) 1998 Masson, Paris .