Salmonella antibiotic therapy

Pneumogstis carini pneumonia (PCP), the most common of the opportunistic infections, occurs in more than 80% of AIDS patients (13). Toxoplasmosis, a proto2oan infection of the central nervous system, is activated in AIDS patients when the 004 count drops and severe impairment of ceU-mediated immunity occurs. Typically, patients have a mass lesion(s) in the brain. These mass lesions usually respond well to therapy and can disappear completely. Fungal infections, such as CTyptococcalmeningitis, are extremely common in AIDS patients, and Histop/asma capsulatum appears when ceU-mediated immunity has been destroyed by the HIV vims, leading to widespread infection of the lungs, Hver, spleen, lymph nodes, and bone marrow. AIDS patients are particularly susceptible to bacteremia caused by nontyphoidal strains of Salmonella. Bacteremia may be cleared by using antibiotic therapy. 

Patients with complicated typhoid fever (i.e., metastatic foci, ileal perforation, etc.) should receive parenteral therapy with ciprofloxacin 400 mg twice daily or ceftriaxone 2000 mg once daily. Antimicrobial therapy can be completed with an oral agent after initial control of the symptoms of typhoid fever. In persons with AIDS and a first episode of Salmonella bacteremia, a longer duration of antibiotic therapy (1-2 weeks of parenteral therapy followed by 4 weeks of oral fluoroquinolone) is recommended to prevent relapse of bacteremia. 

HOST FACTORS A critical determinant of antibiotic efficacy is the status of the host humoral and cellular defense mechanisms. In the immunocompetent host, merely halting the multiplication of the microorganism with a bacteriostatic agent frequently is sufficient to cure the infection. If host defenses are impaired, bacteriostatic activity may be inadequate and a bactericidal agent is required for cure. Examples where this applies include bacterial endocarditis, bacterial meningitis, and disseminated bacterial infections in nentropenic patients. Patients with HIV-1 infection and acquired immunodeficiency syndrome have impaired cellular immune responses. Therapy for opportunistic infection therefore often is snppressive bnt not cnrative disseminated infections with Salmonella or atypical mycobacteria typically require prolonged antibiotic therapy to prevent relapse. 

Infection risk A brain abscess due to Salmonella heidelberg was successfully treated with craniotomy and drainage followed by antibiotic therapy in a 50-year-old woman with myasthenia gravis who had taken azathioprine 200mg/day for more than 10 years [166 ]. 

Salmonella gastroenteritis is usually self-limited, and antibiotics have no proven value. Patients respond well to ORT. Symptoms typically diminish in 3 to 7 days without sequelae. Antibiotic use may result in a higher rate of chronic carriage and relapse. Antimicrobial use should be limited to preemptive therapy among patients at higher risk for extraintestinal spread or invasive disease (Table 73-3). Antimotility agents should not be used. 

Jason Kindrachuk is a postdoctoral fellow at the University of British Columbia (UBC) in the laboratory of Professor R. E. W. Hancock. Jason received his Ph.D. from the University of Saskatchewan in 2007 where his research focused on host and pathogen sensory systems. During his study he specially focused on TLR-9 receptor—ligand interactions and the interactions between host defense peptides and the PhoPQ two-component sensory system of Salmonella typhimurium. In 2008 Jason received the Canadian Cystic Fibrosis Foundation Kin Canada Fellowship for his research in the area of alternative therapies for treatment of antibiotic- and multidrug-resistant bacteria. Currently his research is focused on the investigation of structure-activity relationships amongst natural and synthetic host defense peptides from the perspective of associated immunomodulatory activities and as well as vaccine formulation strategies. 

Typhoid fever caused by Salmonella typhi or S. paratyphi is an important and prevalent cause of continuous fever without localizing symptoms in the tropics. The diagnosis can be confirmed with a bloodculture. Response on therapy is often seen only after 3 days when the fever subsides. Chloramphenicol-resistant Salmonella typhi was first described in Vietnam in 1973. Its prevalence reached 95% in the 1970s and then decreased to 54% in the 1980s after cotrimoxazole became the treatment of choice. In the mid-1993, there was a dramatic increase in the number of strains of S. typhi, isolated in the hospital and from patients in the outbreaks, which are resistant to the three first-line antibiotics chloramphenicol, cotrimoxazol and ampicillin. This indicated that there was an urgent need for effective antibiotics for the treatment of typhoid fever. 

TMP-SMX is also used in the treatment of infection caused by ampicillin-resistant Shigella spp. and for antibiotic-resistant Salmonella spp.. The combination is also effective for covering the carrier state of Salmonella typhi, the agent of typhoid fever, and other Salmonella spp.. Successful treatment of traveler s diarrhea due to susceptible E. coli is another advantage of the use of this combination. The combination is not indicated in the therapy of enterohemorrhagic E. coli strains such as 0157 H7 because of the risk of developing hemolytic-uremic syndrome associated with the release of the cytotoxic enterotoxin by the drugs. 

Most cases of non-typhoid, salmonella infections are self-limited and do not require antimicrobial therapy. Oral electtolyte and glucose solution per os is the mainstay of management for dehydration. Oral antibiotics are indicated in protracted... 

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