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Biomedical subjects

W T Siebert

Publications and source records attributed to W T Siebert.

10 recordsLinked to original sources
PubMed1979

Synergy of vancomycin plus cefazolin or cephalothin against methicillin-resistance Staphylococcus epidermidis.

The in vitro activity of cephalothin, cefazolin, and vancomycin against 25 isolates of methicillin-resistant Staphylococcus epidermidis was determined by means of a broth dilution technique with two sizes of inoculum. The size of the inoculum had a marked effect on the minimal inhibitory concentrations and the minimal bactericidal concentrations of all three antibiotics. With a small inoculum, 100% of the isolates were inhibited by 3.12 micrograms of vancomycin/ml, 76% by 12.5 micrograms of cephalothin/ml, and 64% by 12.5 micrograms of cefazolin/ml. With a large inoculum 100% of the isolates were inhibited by 200 micrograms of vancomycin/ml, 40% by 12.5 micrograms of cephalothin/ml, and 12% by 12.5 micrograms of cefazolin/ml. As determined by a tube dilution checkerboard technique for both sizes of inoculum, the combination of vancomycin plus cephalothin was synergistic against methicillin-resistant S. epidermidis in 45 of 50 cases, and the combination of vancomycin plus cefazolin was synergistic in 39 or 50 cases. These data from in vitro studies suggest that these antibiotic combinations should be evaluated clinically in patients with severe infections caused by methicillin-resistant S. epidermidis.

Cefazolin↗
PubMed1978

Methicillin-resistant Staphylococcus epidermidis.

Staphylococcus epidermidis is frequently associated with infection of prosthetic heart valves, prosthetic orthopedic devices, and neurosurgical shunts. Penicillinase-resistant semisynthetic penicillins, such as methicillin, have been the therapeutic and prophylactic agents of choice for S epidermidis infection. However, more S epidermidis isolates are now resistant to methicillin and other penicillins. In our laboratory 41% of S epidermidis isolates were resistant to methici-lin. All of the methicillin-susceptible isolates and 82% of the methicillin-resistant isoates were susceptible to cephalothin. Cephalothin should replace methicillin as the prophylactic and therapeutic agent of choice in institutions with a high percentage of methicillin-resistant S epidermidis.

Cephalothin↗
PubMed1978

Prosthetic valve endocarditis.

PVE is increasingly frequent and often lethal. The classic features of infective endocarditis may be absent early in the course of the illess. Therefore, patients with prosthetic heart valves and fever must be considered candidates for this infection until another cause for the fever can be established. Five to six blood cultures will document the persistent bacteremia of PVE in most cases. Treatment consists of parenteral penicillins for sensitive organisms plus valvular re-replacement for intractable heart failure mechanical malfunction of the valve, persistent sepsis, or multiple major emboli. In spite of aggressive therapy, the mortality remains high. Therefore, appropriate prophylaxis is warranted in patients with prosthetic valves who must undergo procedures that might lead to bacteremia.

Anti-Bacterial Agents↗
PubMed1977

Resistance to gentamicin: a growing concern.

Gentaminic was introduced in 1969 as a broad-spectrum aminoglycoside effective in vitro against a majority of aerobic gram-negative bacilli. In recent years gentamicin-resistant clinical isolates have become more prevalent. In our laboratory in 1975, 32% of Pseudomonas sp and 44% of indole-negative Proteus sp isolates were resistant to gentamicin. Resistance to tobramycin is also increasing; 24% of Escherichia coli and 28% of indole-negative Proteus sp isolates were found to be tobramycin-resistant. In addition, isolation of previously uncommon gentamicin-resistant species, ie, Proteus rettgeri and other indole-positive Proteus sp, from clinical specimens has increased dramatically in the past five years. This increase in gentamicin and tobramycin-resistant gram-negative bacilli serves as a constant stimulus for the development of new antimicrobial agents.

Drug Resistance, Microbial↗
PubMed1976

Chronic consumption coagulopathy accompanying abdominal aortic aneurysm.

Each of two patients harboring a stable abdominal aortic aneurysm manifested severe recurrent bleeding consequent to chronic consumption coagulopathy (CCC). Both underwent successful aneurysmectomy, but in only one patient did bleeding cease and depressed clotting factors return to normal activity. In the other patient, subsequent observations suggested that his coagulopathy actually resulted from occult pancreatic carcinoma. We propose here criteria for establishing stable aneurysm as the cause of CCC and demonstrate the efficacy of heparin in reversing the coagulation defect prior to surgical intervention. These cases also illustrate that the discovery of CCC accompanying stable aneurysm may signal the presence of another underlying disorder.

Aged↗
PubMed1976

Comparison of thrombophlebitis associated with three cephalosporin antibiotics.

A double-blind study with volunteers was performed to determine the incidence and severity of thrombophlebitis associated with cephalothin, cephapirin, cefamandole, and a water control. Although there were no statistical differences in the incidence of thrombophlebitis, cephalothin resulted in significantly more severe thrombophlebitis compared with the other agents.

Cephalosporins↗
PubMed1975

Antimicrobial susceptibility of clinical isolates of gram-negative bacilli.

No one can doubt the increased incidence of gram-negative bacillary infections and the importance of an awareness of this increase. Today's hospital, where one finds aggressive surgery, patients with multiple indwelling polyethylene lines and Foley catheters, and widespread use of prophylactic antibiotics, serves as a haven for resistant gram-negative bacilli. Twenty-five strains of Escherichia coli, Klebsiella sp, Enterobacter sp, Pseudomonas sp, indole-negative Proteus sp, indole-positive Proteus sp, and Serratia sp from hospitalized patients were tested for susceptibility to eight commonly used antibiotics using an inocula replicating method. Gentamicin proved to be the most effective antibiotic against the majority; most strains were inhibited by 3.12mug/ml or less. Other antibiotics, although not so active against all species, were effective against selected species.

Administration, Oral↗
PubMedDate not supplied

Combined effects of ticarcillin and cefazolin on blood coagulation and platelet function.

Combined intravenous infusions of ticarcillin and cefazolin given to normal volunteers resulted in a functional platelet defect which appeared to be determined primarily by the dose and duration of treatment with the penicillin component. No effect on soluble blood coagulation factors was evident. Acute administration of corticosteroids did not influence the prolonged bleeding times induced by extended ticarcillin infusions.

Blood Coagulation↗