Biomedical subjects
L C Preheim
Publications and source records attributed to L C Preheim.
Antigen detection in the diagnosis and in the prognostic assessment of bacterial pneumonias.
Sputum cultures are not helpful in the immediate management of patients with bacterial pneumonia. Sputum Gram stains may provide a presumptive identification of an etiologic agent; this procedure, however, is insensitive (approximately 50%). Consequently, during the last decade, other more sensitive and specific methods of providing a rapid etiologic diagnosis have been sought. This article discusses data on antigen detection in various body fluids by counterimmunoelectrophoresis and agglutination tests. Results from our own laboratory as well as those reported in the literature are presented. The best estimates of antigen detection rates, by the most sensitive assays, in pneumococcal pneumonia, are as follows: serum, 45%-80%; urine, 50%-64%; and sputum, 75%-100%. There is less information for Haemophilus, Klebsiella, and Pseudomonas pneumonias, but the diagnostic yield is approximately 50%-100%. Data will also be presented on the association between free and complexed antigens and morbidity and mortality in pneumococcal pneumonia. Indicators of morbidity discussed include disseminated intravascular coagulation, duration and severity of illness, and occurrence of nephritis.
Randomised comparison of ceftriaxone and cefamandole therapy in lower respiratory tract infections in an elderly population.
Patients with pneumonia or bronchitis were randomized to receive ceftriaxone or cefamandole. A total of 30 of 38 patients were evaluable, 16 in the ceftriaxone group (average age 66.3 years) and 14 in the cefamandole group (average age 69.4 years). All but one had underlying diseases. Patients usually received 1 g of ceftriaxone intravenously every 12 h (mean duration 8.7 days) or 1.5 g of cefamandole intravenously every 6 h (mean duration 8.2 days). Adverse experiences attributable to the drugs were confined to one episode of discomfort at the infusion site in each group. Bacteriological results with ceftriaxone were 83% cured, 11% superinfected after eradication of pretherapy isolate, and 6% failed. Bacteriological results with cefamandole were 76% cured, 24% failed. Clinical results with ceftriaxone were 38% cured, 56% improved, 6% failed. Clinical results with cefamandole were 57% cured, 21% improved, 21% failed. Emergence of a resistant Serratia marcescens was seen in a ceftriaxone-treated patient. Disc diffusion susceptibility testing identified six of the seven pretherapy nonfastidious Gram-negative isolates as susceptible; however, two of the six could not be eradicated with the assigned drug and another two were eradicated with ensuing super-infection with susceptible isolates of Pseudomonas aeruginosa. In contrast, MBCs were an accurate guide to clinical outcome with nonfastidious Gram-negative bacilli.
Relationships between alternative complement pathway activation, C-reactive protein, and pneumococcal infection.
In the absence of specific antibody, opsonization of Streptococcus pneumoniae may be mediated by the alternative complement pathway (AP) or by C-reactive protein (CRP) via C1 binding. To determine the role of these mechanisms in pneumococcal (PNC) disease, we studied 19 patients with differing severities of PNC infection. C4 and CRP levels and zymosan-induced consumption of 50% hemolytic complement (CH50) were measured in specimens obtained acutely and then weekly. In patients with complicated illness, the modified mean CH50 in acute sera was 178 +/- 57 U/ml, significantly lower than the mean CH50 of 331 +/- 80 U/ml in patients with uncomplicated illness (P less than 0.05). The values of the two groups on a given day approximated each other on days 7, 14, and 23. Consumption of complement by zymosan was also lower in acute sera of patients with complicated illness, with a mean value of 19 +/- 18 U/ml compared with 58 +/- 30 U/ml in those with uncomplicated illness (P less than 0.05). This difference was also seen on day 7 (P less than 0.05). Disease involving lower-numbered PNC serotypes (less than 10) correlated with reduced availability of AP factors in acute sera, independent of illness severity. Mean CRP levels were inversely related to zymosan-induced complement activation in patients with complicated illness. These data suggest that in vivo depletion of AP factors is significantly greater in patients with complicated illness and is associated with high CRP levels. CRP may enhance AP activation via C3 convertase generation and function with it as a preantibody host defense mechanism.
Imported malaria: problems with diagnosis and prevention.
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Complicated urinary tract infections.
The distinction between complicated and uncomplicated urinary tract infections is usually based on the presence or absence of some abnormality in the path of urine flow. Other differences include characteristic patient profiles, usual setting, likely pathogens and their antimicrobial susceptibility, and treatment options. Complicated infections are most common in older patients, usually men with prostatic enlargement. Gram-negative bacilli are the most frequent pathogens, but Escherichia coli plays a less dominant role. Isolates from patients with complicated infections are more likely to be resistant to older antibiotics, and therapy is usually parenteral. Many complicated urinary tract infections are hospital-acquired, and are often due to indwelling urinary catheters. Resistance to antimicrobials among isolates is common in this setting. Nosocomial urinary tract infections contribute substantially to morbidity, mortality, and health care costs. Numerous effective treatment options are available for uncomplicated infections. The types of patients, predisposing factors, and organisms limit antimicrobial choices for complicated infections. Although new antibiotics offer certain advantages, final therapeutic success usually depends on resolving the disorder that predisposes the patient to infection.
Randomized, double-blind comparison of ceftazidime and moxalactam in complicated urinary tract infections.
Sixty-seven patients with complicated urinary tract infections were randomized in double-blind fashion to ceftazidime or moxalactam (MOX). A total of 54 patients were evaluable, 27 in each group. Patients received 500 mg of antibiotic intravenously every 12 h, except for those with Pseudomonas aeruginosa randomized to MOX who received 2 g intravenously every 12 h. Toxic effects with ceftazidime were experienced by the following number of patients: pain with infusion, one; posttherapy diarrhea, one; liver function test elevations, two; and neutropenia, one. Toxic effects with MOX were experienced by the following number of patients: liver function test elevations, two; and prolonged prothrombin time, one. All resolved. At 1 week posttherapy, bacteriologic results were 74% cured, 11% relapsed, 15% reinfection with ceftazidime and 52% cured, 33% relapsed, and 19% reinfection with MOX. Ceftazidime was effective for infections caused by MOX-resistant P. aeruginosa. P. aeruginosa resistant to MOX and other beta-lactams was isolated from one patient after MOX therapy. Enterococcal reinfection was common in both groups.
Cellulitis associated with dermatophyte infection in the vein-donor-leg of a coronary artery bypass patient.
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Short-course chemotherapy for pulmonary infection due to Mycobacterium bovis.
Three residents of The Open Door Mission of Omaha developed pulmonary infections due to Mycobacterium bovis. All were alcoholics with malnutrition. The disease was most likely due to reactivation of a primary infection acquired at least 30 years earlier in the index case. Both of the secondary patients had been treated more than ten years previously for infections due to Mycobacterium tuberculosis. Supervised short-course chemotherapy was effective in treating the disease caused by Mycobacterium bovis.
Ceftriaxone therapy of serious bacterial infections in adults.
We evaluated the efficacy and safety of ceftriaxone in 50 adults with serious infections, usually giving 1 g every 12 h. Of the 35 patients who could be evaluated for clinical efficacy, 15 had failed on previous therapy, 15 had nosocomial infections, and all but 1 had underlying diseases. One patient had three sites of infection. Favorable responses were seen in 34 of 37 infections, including 11 of 13 respiratory tract infections, all 7 urinary tract infections, all 12 skin and soft tissue infections, 1 of 2 bone and joint infections, a catheter-related septicemia, a liver abscess, and an otitis media and externa. Favorable bacteriological responses were seen for 48 of 58 organisms. This included 6 of 7 Staphylococcus aureus strains, 14 of 16 other aerobic gram-positive cocci, 18 of 20 Enterobacteriaceae, 6 of 9 Pseudomonas aeruginosa, and 1 of 2 anaerobes. Peak plasma ceftriaxone levels on day 1 were 152 micrograms/ml by bioassay and 78 micrograms/ml by high-pressure liquid chromatography. Four of the 31 initial isolates of aerobic gram-negative rods developed resistance to ceftriaxone on disk diffusion testing. Diarrhea occurred in 3 of 50 patients. All three had received a higher than usual dose. Drug administration was stopped twice, once for a thrombocytopenia and once for a thrombocytopenia with leukopenia. Neither problem could be attributed exclusively to ceftriaxone. Other adverse reactions were eosinophilia, abdominal pain, inguinal candidiasis, and nonsuppurative phlebitis. Even among debilitated adults, ceftriaxone was safe and effective in a twice daily regimen.
Comparison of moxalactam and gentamicin in the treatment of complicated urinary tract infections.
Moxalactam and gentamicin were compared in a prospective, randomized study of 49 hospitalized patients with complicated urinary tract infections. Patients received parenteral moxalactam, 250 mg every 12 h, or gentamicin, 1 mg/kg every 8 h. The average duration of therapy (moxalactam, 7.5 days; gentamicin, 8.6 days) was similar for both groups. Sixty-two percent of patients treated with moxalactam and 57% of those receiving gentamicin were cured of their infection, as defined by a negative culture after therapy. No side effects required discontinuation of either drug. An enterococcus caused two superinfections and three reinfections in patients treated with moxalactam. Moxalactam resistance developed in Pseudomonas aeruginosa isolates from three patients treated with moxalactam. Moreover, two of these isolates showed decreased susceptibility to gentamicin, tobramycin, and amikacin. An additional 10 patients with gentamicin-resistant but moxalactam-susceptible isolates were treated with moxalactam. Forty percent of these patients were cured of their infections. Moxalactam appears to be a safe, effective drug for complicated urinary tract infections caused by susceptible bacteria, including those resistant to gentamicin. However, patients receiving moxalactam should be carefully monitored to detect enterococcal superinfections or development of resistance to moxalactam in isolates of P. aeruginosa.
Emergence of resistance to beta-lactam and aminoglycoside antibiotics during moxalactam therapy of Pseudomonas aeruginosa infections.
In four patients with Pseudomonas aeruginosa infections, the infecting strain developed resistance to moxalactam during therapy with this drug. In addition, P. aeruginosa isolates from two of these four patients showed increased resistance to aminoglycosides. Isolates from a third patient acquired cross-resistance to other antipseudomonal beta-lactams. In three of the cases, disk susceptibility tests failed to detect the resistance that was demonstrated in broth dilution assays. Isolate identities were confirmed by serotyping. No new plasmids were found by agarose gel electrophoresis. The mechanisms for this resistance did not involve enzymatic antibiotic degradation. These findings suggest that currently available expanded-spectrum cephalosporin derivatives should probably not be used alone for most serious infections due to P. aeruginosa. They also suggest that strains with multiple antibiotic resistance may become more prevalent in hospitals if these drugs are used extensively.
Plesiomonas shigelloides overgrowth in the small intestine.
An 83-year-old male presented with chronic diarrhea and protein malnutrition associated with Plesiomonas shigelloides overgrowth in the small intestine. This overgrowth was related to achlorhydria and small-bowel diverticula. Tests for heat-labile and heat-stable enterotoxin were negative on the P. shigelloides isolated from both the small bowel aspirate (3 x 10(8) bacteria per ml) and the patient's stool. The patient responded satisfactorily to tetracycline, to which this unusual isolate was susceptible in vitro. The ability to correctly identify and determine the antimicrobial susceptibility of P. shigelloides in the setting of small-bowel overgrowth will help determine appropriate therapy.