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Biomedical subjects

J J Rahal

Publications and source records attributed to J J Rahal.

At least 19 recordsLinked to original sources

Effect of a beta-lactamase inhibitor, tazobactam, on growth and penicillin-binding proteins of Borrelia burgdorferi.

The effects of tazobactam, a relatively new beta-lactamase inhibitor, were investigated on growth and penicillin-binding proteins (PBPs) of Borrellia burgdorferi. A previous communication from our group demonstrated several proteins capable of binding labelled penicillin in this organism. Of these proteins, 94-kDa and 57-kDa PBPs possessed the highest affinity for penicillin and were assumed to be essential proteins involved in cell-wall synthesis. In these experiments, tazobactam was used in competition binding experiments as well as on whole spirochetes. Only the 94-kDa and 57-kDa PBPs were affected by increasing amounts of tazobactam during competition-binding experiments and growth of B. burgdorferi was also inhibited. These results may explain the in vitro activity of beta-lactamase inhibitors in general and suggest a utility for these compounds when examining PBPs with hydrolysing activity and/or organisms with beta-lactamases.

Bacterial Proteins

Role of candida in pathogenesis of antibiotic-associated diarrhoea in elderly inpatients.

The part that candida plays in antibiotic-associated diarrhoea was investigated in 24 elderly inpatients (mean age 74 years) who tested negative for Clostridium difficile toxin and other intestinal pathogens. 7 had intestinal overgrowth of Candida species (greater than or equal to 10(5) cfu/ml). None of the 24 matched, antibiotic-treated controls without diarrhoea had candida overgrowth. All 5 patients with diarrhoea and candida overgrowth treated with oral nystatin responded with resolution of diarrhoea and lowering of faecal counts to less than 10(4) cfu/ml within 7 days of start of antifungal therapy despite continuation of antibacterial therapy. In the other 2 patients with candida overgrowth, the diarrhoea subsided spontaneously and faecal candida counts returned to normal (less than 10(4) cfu/ml) after antibacterial agents were withdrawn. In patients without candida overgrowth, diarrhoea persisted until antibiotics were withdrawn, at a mean of 16 days after study entry.

Aged

Penicillin-binding proteins in Borrelia burgdorferi.

Penicillin-binding proteins were identified in Borrelia burgdorferi membranes. A 94-kilodalton penicillin-binding protein was the first to be labeled with tritiated penicillin and was the first band to disappear in a competition experiment. Its binding ability was destroyed when membranes were preboiled. In addition, several of these penicillin-binding proteins comigrated with bands previously identified as surface proteins.

Bacterial Proteins

Association of teichoic acid antibody with metastatic sequelae of catheter-associated Staphylococcus aureus bacteremia: a failure of the two-week antibiotic treatment.

A patient with Staphylococcus aureus bacteremia associated with an infected intravenous catheter was treated with oxacillin for two weeks. During that period all blood cultures were sterile, he rapidly became afebrile, and there were no signs of endocarditis or metastatic abscesses. However, serum antibodies against staphylococcal teichoic acid, initially undetectable by the agar gel immunodiffusion technic, became positive during the second week of treatment. Three weeks after discharge, the patient was readmitted to the hospital because of back pain and weakness in the lower extremities. Vertebral osteomyelitis and a spinal epidural abscess caused by Staph. aureus of the same phage type as the bacteremic isolate were demonstrated. This case illustrates the importance of careful follow-up of patients with Staph. aureus bacteremia and the potential value of serial measurement of teichoic acid antibodies in detecting clinically inapparent complications of infection.

Abscess

Bactericidal and bacteriostatic action of chloramphenicol against memingeal pathogens.

The bacteriostatic and bactericidal effects of chloramphenicol, ampicillin, tetracycline, and sulfisoxazole were compared against several potential meningeal pathogens. Chloramphenicol is bactericidal at clinically achievable concentrations against Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis. It is bacteriostatic against gram-negative bacilli of the family Enterobacteriaceae and against Staphylococcus aureus. Chloramphenicol has proven highly efficacious in the treatment of bacterial meningitis caused by those organisms against which it is bactericidal at low concentrations. Because leukocytic phagocytosis in the subarachnoid space is inefficient, we propose that bactericidal activity in cerebrospinal fluid is important for optimal therapy of bacterial meningitis. Chloramphenicol does not provide such activity in meningitis caused by enteric gram-negative bacilli.

Ampicillin

Antibiotics: how to use them in 1977-1978. Cases 21, 22, and 23.

Self-assessment case studies illustrating prudent selection of antimicrobial agents in septic shock following urinary catheterization, bacteremia and skin lesions in an immunocompromised patient, and endocarditis in a patient with a prosthetic heart valve.

Adult

Hepatitis associated with high-dose oxacillin therapy.

A prospective survey of liver function during oxacillin sodium therapy revealed five cases of drug-related abnormalities among 41 patients. In each instance, the serum transaminase level was increased from normal to greater than 100 units. The serum alkaline phosphatase level was mildly elevated and bilirubin levels remained normal. All of the patients were asymptomatic. Hepatic dysfunction was reversible on withdrawal of oxacillin therapy and substitution of a cephalosporin or clindamycin. The observed abnormalities in liver function were associated with a daily oxacillin sodium dose of greater than or equal to 12 gm as well as with heroin addiction and staphylococcal endocarditis.

Adult