Gram-negative bacteria pathogenic

Leucocidins kill leucocytes and are produced by many strains of streptococci, most strains of Staphylococcus aureus and likewise most strains of pathogenic Gram-negative bacteria, isolated from sites of infection. 

Intra-abdominal operations involve a diverse flora with the potential for polymicrobial SSIs. Escherichia coli make up a large portion of bowel flora and are frequently isolated as pathogens according to the NNIS.5 Other enteric gram-negative bacteria, as well as anaerobes (especially Bacteroides spp.), may be encountered during intra-abdominal operations. 

Rifaximin, a virtually nonabsorbed antibiotic, is a semisynthetic rifamycin derivative, with a broad antimicrobial spectrum that includes most Gram-positive and Gram-negative bacteria, both aerobes and anaerobes [1, 2], Unlike systemically available antibiotics, this antimicrobial allows localized targeting (e.g. enteric or cutaneous) of pathogens and is associated with a minimal risk of systemic toxicity or side effects [3, 4], Provided that nonabsorbed antibiotics are as effective as systemically absorbed drugs for the target illness, their safety and toler-... 

Many bacteria secrete a wide range of proteins including pathogenic factors such as toxins. They must pass through both the outer and inner membranes. There are various mechanisms for protein secretion. Among them, three pathways are conserved in many species of gram-negative bacteria (Salmond and Reeves, 1993 Nunn, 1999). 

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