Human disease, bacterial pathogens

Antibiotics have been used for the treatment of infectious diseases and for a number of non-human applications (agriculture, animal husbandry, and aquaculture) during the past 70 years (Levy and Marshall 2004). Prior to the introduction of antibiotics, natural populations of human/animal bacterial pathogens or commensal bacteria were susceptible to antibiotics (Hughes and Datta 1983). Immediately after the entry of antibiotics in the treatment of infectious diseases, the appearance of antibiotic-resistant bacteria was observed. Today, the overwhelming majority of enterobacteria are resistant to sulfonamides, the first antibacterial chemotherapeutics introduced in clinical practice in 1937. Additionally, a high proportion of bacteria are resistant to a broad range of penicillins, streptomycin, chloramphenicol, and tetracyclines. 

V. Nizet, Antimicrobial Peptide Resistance in Human Bacterial Pathogens. In Antimicrobial Peptides in Human Health and Disease] R. L. Gallo, Ed. Horizon Bioscience Norfolk, VA, 2005 pp 277-304. 

Salmonella enterica (S. enterica) is a rod-shaped Gram-negative facultative anaerobe and a prominent enteric bacterial pathogen capable of causing food- and water-related diseases. Several serovars of S. enterica are associated with human infection. The principle clinical diseases associated with Salmonella infection are typhoid fever and gastroenteritis. S. enterica serovars Typhi S. Typhi) and Paratyphi (,S. Paratyphi) are pathogenically exclusive for humans and are known to cause typhoid or enteric fever (Ohl and Miller, 2001). Typhoid fever is a systemic infection characterized by the development of fever, abdominal pain, enterocolitis, and occasionally, a maculopapular rash. The hallmark feature of typhoid fever is the presence of mononuclear cell infiltration and hypertrophy of the intestinal Peyer s patches and mesenteric lymphoidal tissue (Kraus et al., 1999 Ohl and Miller, 2001). There are approximately 20 million cases of typhoid fever worldwide each year, and this acute and often life-threatening infection is responsible for over 200,000 deaths annually (Crump et al., 2004). 

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