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Biomedical subjects

R S Edson

Publications and source records attributed to R S Edson.

At least 37 records · Page 2Linked to original sources

Antimicrobial agents in urinary tract infections.

Urinary tract infections are commonly encountered in clinical practice and are usually readily treatable. Although many antimicrobial agents that have been available for some time remain effective in the eradication of bacteriuria, the recent introduction of the fluoroquinolone norfloxacin represents an important addition to the therapeutic armamentarium. The efficacy of single-dose therapy with antimicrobial agents such as trimethoprim-sulfamethoxazole or amoxicillin has been shown to be similar to that with conventional (7- to 10-day) treatment in women with uncomplicated lower urinary tract infections. The long-term administration of agents such as trimethoprim-sulfamethoxazole or nitrofurantoin in low doses is usually effective for suppression or prophylaxis of recurrent bacteriuria.

Acute Disease↗

Saksenaea vasiformis osteomyelitis.

A 24-year-old man sustained a crush injury to the tibia, which subsequently became infected with Saksenaea vasiformis. He was treated with debridement and a free myocutaneous flap, but amputation was necessary because of mycotic osteomyelitis. S. vasiformis was recovered and identified on the basis of its characteristic morphology on cornmeal agar.

Adult↗

Comparison of Du Pont Isolator and Roche Septi-Chek for detection of fungemia.

The rapid detection of fungemia in hospitalized patients is imperative, particularly for those who are immunocompromised. Our laboratory compared the Roche Septi-Chek with the Du Pont Isolator for the recovery of fungi from blood. Of 23,586 matched pairs of blood cultures, 199 were positive. The Isolator detected 178 (89.4%) and the Septi-Chek detected 119 (59.7%) of all positive isolates. The mean recovery time for the Isolator and Septi-Chek was 2.2 and 4.9 days, respectively. The Isolator detected fungemia earlier than the Septi-Chek did and was the only culture system positive in 83% of 53 patients, whereas the Septi-Chek system yielded the same results in only 13% of the patients. The Isolator provides a more rapid and sensitive method for the recovery of fungi from blood.

Blood↗

Polymicrobial cholangitis and Kaposi's sarcoma in blood product transfusion-related acquired immune deficiency syndrome.

Before presenting to the Mayo Clinic, a 24-year-old white woman had received 35 transfusions of blood products over a 72-hour period in February 1981. Two and one half years later, the diagnosis of polymicrobial cholangitis (Cryptosporidium, Candida albicans, and Klebsiella pneumoniae) was established. Further evaluation demonstrated profound helper T lymphocyte suppression, disseminated Mycobacterium avium-intracellular infection with mycobacteremia, and Kaposi's sarcoma of lymphoid tissue, confirming a diagnosis of acquired immune deficiency syndrome (AIDS). This case represents an unusual infectious complication of AIDS. Additionally, this is believed to be the first report of Kaposi's sarcoma occurring in a patient with AIDS associated with blood product transfusion.

Acquired Immunodeficiency Syndrome↗

Cytomegalovirus infection in patients undergoing noncardiac surgical procedures.

A search for records for CMV infection following transfusion related to noncardiac and nontransplant operations and trauma disclosed nine instances with CMV seroconversion. One patient had received only a single unit of blood. The most prominent feature was fever with a characteristic spiking plateau pattern, which began approximately three weeks after blood transfusion. Splenomegaly and atypical lymphocytosis were less common. The results of hepatic function tests showed slight abnormalities. Associated splenectomy did not result in a more severe manifestation of the CMV infection. The late postoperative fever in these patients led to an extensive and costly investigation before determination of antibody titers to CMV and confirmation of seroconversion. When faced with the constellation of symptoms, including a delayed (two to three weeks) spiking plateau postoperative fever, abnormal results of hepatic function test and lymphocytosis in patients having received blood transfusion, the clinician must give serious consideration to the possibility of CMV infection.

Adolescent↗

Trimethoprim/sulfamethoxazole-resistant Nocardia asteroides causing multiple hepatic abscesses. Successful treatment with ampicillin, amikacin, and limited computed tomography-guided needle aspiration.

Hepatic abscesses are rarely encountered in disseminated Nocardia infections. Sulfonamides alone or trimethoprim/sulfamethoxazole is often efficacious in treating infections caused by Nocardia asteroides. In vitro resistance of N. asteroides to trimethoprim/sulfamethoxazole is occasionally present. The patient described in this report had disseminated nocardiosis initially manifesting as multiple subcapsular hepatic abscesses. In vitro susceptibility studies demonstrated resistance to trimethoprim/sulfamethoxazole. Subsequent treatment with ampicillin and amikacin in conjunction with computed tomography-guided needle aspiration of several of the hepatic abscesses, surgical drainage of a right pleural empyema, and eventual discontinuation of use of corticosteroids resulted in cure of the infection.

Amikacin↗

Empiric therapy with moxalactam alone in patients with bacteremia.

Moxalactam was administered (20 mg/kg intravenously every 8 hours) as single-drug empiric antimicrobial therapy to 63 patients with bacteremia who were neither neutropenic nor immunosuppressed. Six patients (10%) had microorganisms that were susceptible to moxalactam and resistant to all other antimicrobial agents tested; two patients (3%) had microorganisms that were resistant to moxalactam and other agents tested. Of these 63 patients, 47 (75%) were cured with moxalactam therapy. Nine patients (14%) had breakthrough bacteremia while receiving other antimicrobial therapy and were cured subsequently with moxalactam therapy alone. The two major risk factors for failure of moxalactam therapy were polymicrobial bacteremia and an extrahepatic intra-abdominal source of infection; these two conditions frequently coexisted. Six of nine patients with polymicrobial bacteremia died. Superinfection (one pseudomonal, five enterococcal) was responsible for 6 of the 16 treatment failures. Enterococcal superinfection occurred exclusively among patients who had received relatively prolonged therapy with moxalactam for extrahepatic intra-abdominal infection, especially intraabdominal abscess. These five patients died, and postmortem examination showed that enterococcal superinfection was the major cause of death in all. Mild, reversible adverse reactions associated with use of moxalactam occurred in 14 of the 63 patients (22%). None had clinically overt bleeding. The use of moxalactam alone seems to be safe and effective and a cost-effective alternative empiric antimicrobial therapy for most patients with bacteremia who are not immunosuppressed or neutropenic and who are not at high risk of having Pseudomonas or polymicrobial bacteremia.

Abdomen↗

Clinical evaluation of the lysis-centrifugation blood culture system for the detection of fungemia and comparison with a conventional biphasic broth blood culture system.

In a comparative fungal blood culture study, a lysis-centrifugation system (Isolator; Du Pont Co., Wilmington, Del.) detected 89% of all episodes of fungemia; the lysis-centrifugation system detected fungemia exclusively or significantly earlier than did a biphasic brain heart infusion bottle system 83% of the time. The lysis-centrifugation system was particularly useful in the early detection of fungemia caused by Candida tropicalis and Candida glabrata. In 53% of the clinically significant episodes, the earlier detection was directly helpful in the management of patients with fungemia. High-magnitude candidemia (greater than 5 CFU/ml of blood) was significantly associated with the presence of an infected intravascular catheter and with Candida species other than Candida albicans. The lysis-centrifugation system was sensitive in the detection of fungemia during the monitoring of patients receiving antifungal agents or after removal of an infected intravascular catheter.

Candidiasis↗

Bactericidal and synergistic activity of moxalactam alone and in combination with gentamicin against Pseudomonas aeruginosa.

The bactericidal activity of moxalactam, alone and in combination with gentamicin, was studied with macrobroth two-dimensional checkerboard and killing curve techniques against gentamicin-resistant and -susceptible strains of Pseudomonas aeruginosa. Moxalactam was bactericidal at concentrations equal to or at least two to four times its inhibitory concentrations. Synergy at clinically applicable concentrations of moxalactam and gentamicin occurred with 6 of 14 gentamicin-resistant strains and 4 of 4 gentamicin-susceptible strains by the checkerboard technique and with 7 of 14 gentamicin-resistant strains by the killing curve technique. Synergy between moxalactam and gentamicin against gentamicin-resistant strains of P. aeruginosa is unpredictable and strain- and method-dependent.

Anti-Bacterial Agents↗

Trimethoprim-sulfamethoxazole.

The antimicrobial combination of trimethoprim and sulfamethoxazole is active in vitro against a variety of gram-positive and gram-negative bacteria. Clinically, it is useful for treatment and prophylaxis of various infections of the genitourinary tract and certain infections of the respiratory and gastrointestinal tracts. Trimethoprim-sulfamethoxazole by itself or in combination with other antimicrobial agents is effective for most Nocardia asteroides infections. It is the antimicrobial agent of choice for Pneumocystis carinii pneumonia. The drug is relatively nontoxic and available in oral and intravenous forms. The native compounds and the metabolites of trimethoprim and sulfamethoxazole are excreted primarily in the urine. When the creatinine clearance decreases to less than 30 ml/min, the dosage of trimethoprim-sulfamethoxazole should be adjusted.

Bacterial Infections↗

Metronidazole.

Metronidazole, a nitroimidazole derivative, is a unique antimicrobial agent that is active against both bacterial and parasitic organisms, although only the anaerobic members of these groups are susceptible. It has been used for the treatment of trichomoniasis for about 20 years and is also effective against amebiasis and giardiasis. More recently, metronidazole has emerged as a principal agent for the treatment of anaerobic bacterial infections. It is highly effective against all species of anaerobes except certain non-spore-forming gram-positive bacilli and cocci and is the only agent rapidly bactericidal against the Bacteroides fragilis group. Clinical studies have proved its efficacy in prophylaxis for elective colorectal surgical procedures and in the treatment of deep abdominal sepsis (usually in combination with another agent, such as an aminoglycoside). Metronidazole is the treatment of choice for nonspecific vaginitis that seems to be a mixed infection due to anaerobes and Gardnerella vaginalis. Adequate concentrations in the blood are produced after both oral and intravenous administration, and the side effects are infrequent and minimal.

Bacteroides Infections↗

Invasive disease caused by Trichosporon beigelii.

An immunocompromised patient had cellulitis that was unresponsive to conventional antimicrobial therapy. Skin biopsy specimens and fungal blood cultures revealed the offending organism as Trichosporon beigelii. Recognition of this opportunistic pathogen in immunocompromised patients is important.

Humans↗

The aminoglycosides. Streptomycin, kanamycin, gentamicin, tobramycin, amikacin, netilmicin, sisomicin.

Despite their toxicity, the aminoglycosides remain useful and are often the first choice in the treatment of serious infections due to gram-negative bacilli. Nephrotoxicity has restricted the indications for neomycin to topical and oral use. Emergence of resistant organisms has limited the use of streptomycin to a few specific conditions. Gentamicin, tobramycin, and amikacin are effective against a broad spectrum of gram-negative bacilli including Pseudomonas aeruginosa. Amikacin is the aminoglycoside of choice when gentamicin resistance is prevalent.

Amikacin↗

Antimicrobial agents in urinary tract infections.

Effective antimicrobial therapy for most urinary tract infections has been available since the sulfonamide era. Innovations in chemotherapy now include single-dose treatment of acute bacterial cystitis and acute urethral syndrome and effective suppression of recurrent bacteriuria with low-dose antimicrobial agents.

Acute Disease↗

Parenteral metronidazole: its use in serious anaerobic infections.

Within a few years of the introduction of oral metronidazole to treat parasitic infections, investigators began to notice its activity against anaerobic infections as well. Now a parenteral form of the drug is available for use in this expanded application. This article reviews the properties and activity of the drug and discusses its new indications.

Bacterial Infections↗

Gas-liquid chromatography of positive blood cultures for rapid presumptive diagnosis of anaerobic bacteremia.

Gas-liquid chromatographic analysis of volatile fatty acid patterns was performed when growth was initially detected in 87 positive blood cultures. Isovaleric acid, butyric acid, or both were found in 39 of 43 (90%) blood cultures that contained anaerobes but were absent in all 44 cultures that contained facultatively anaerobic or aerobic bacteria. The detection of isovaleric acid indicated the presence of Bacteroides fragilis, as this acid was found in 88% of unimicrobial and 75% of polymicrobial bacteremias due to B. fragilis. Butyric acid was detected most often in blood cultures which grew Fusobacterium spp. (three of three), Clostridium spp. (six of seven), or both (three of four).

Bacteroides Infections↗

Recent experience with antimicrobial susceptibility of anaerobic bacteria: increasing resistance to penicillin.

Results of antimicrobial susceptibility testing of anaerobes were reviewed for the last 5 years and compared with two previous surveys from this institution. Allowing for differences in methodology, there appears to be a striking increase in penicillin resistance by the "non-fragilis" Bacteroides. Penicillin concentrations of 50 microgram/ml were required to inhibit 70% of 43 strains tested. The clinical implications of this observation are not known, but isolated reports of therapeutic failure when penicillin was used against the non-fragilis Bacteroides have appeared. Penicillin resistance among Clostridium other than C. perfringens was also noted in the current study. Several strains of clindamycin-resistant Bacteroides fragilis have been observed during the last 2 years, and whether this represents a true increase in resistance will require close scrutiny of clindamycin susceptibility in the future. Future surveillance of antimicrobial susceptibility of anaerobic bacteria will be useful in the detection of any major changes in susceptibility profiles. This knowledge will potentially affect the choice of antimicrobial agent in patients with serious infections caused by anaerobes.

Anti-Bacterial Agents↗