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Biomedical subjects

R H Eng

Publications and source records attributed to R H Eng.

105 records · Page 6Linked to original sources

Infections caused by Actinomyces viscosus.

Two cases of Actinomyces viscosus infection of the lungs were seen in nonimmunosuppressed patients. One patient had a peripheral actinomycotic lung mass resembling a tumor. Both patients responded to a long course of penicillin therapy. Reports of A. viscosus infections are rare, although the organism colonizes the mouths of most adult humans. Only ten cases have previously been described. There is no characteristic of A. viscosus infection that can distinguish it from Actinomyces israelii or Actinomyces bovis infections. The illness usually manifests as a chronic disease weeks to months before the diagnosis, which can only be made by identification of the organism from a clinical specimen uncontaminated by sputum or mouth flora. Ignorance of the biochemical reactions and growth characteristics of this organism have in the past hindered its isolation and identification. At least three weeks of antibiotic therapy using agents to which A. viscosus is sensitive in vitro are required for cure.

Actinomyces↗

Serum levels of arabinitol in the detection of invasive candidiasis in animals and humans.

Arabinitol is a pentitol generated in large quantitites by several species of Candida, including Candida albicans. The level of arabinitol in the sera of infected animals and humans was determined by gas-liquid chromatography of an acetone extract of the serum. Experimentally infected mice with pyelonephritis due to C. albicans had elevated levels of arabinitol; rabbits with pyelonephritis did not have elevated levels, nor did rabbits with catheter-induce cystitis, but rabbits with endocarditis developed elevated levels of arabinitol shortly before death. A prospective study in patients clinically suspected of having invasive candidiasis failed to show elevated levels of arabinitol in most. Mice and patients not colonized or infected with yeasts but with renal failure had high serum levels of arabinitol. The data indicate that an elevated level of arabinitol in the serum of a patient without renal disease is suggestive of invasive candidiasis, but normal serum levels do not contradict the diagnosis.

Adult↗

Susceptibility of zygomycetes to amphotericin B, miconazole, and ketoconazole.

Susceptibility to amphotericin B, miconazole, and ketoconazole was determined for 25 clinical isolates of zygomycetes in yeast nitrogen base broth and human serum. In yeast nitrogen base broth, 7 of 25 isolates were susceptible to an imidazole or amphotericin B. In serum, all were resistant to the imidazoles and inhibited by amphotericin B, the current drug of choice for infections caused by zygomycetes.

Amphotericin B↗

Serum cryptococcal antigen determination in the presence of rheumatoid factor.

Sera from nine patients with cryptococcal infections and from four with rheumatoid arthritis and positive rheumatoid factor were examined for the presence of cryptococcal capsular antigen by the latex agglutination method. Ethylenediaminetetraacetic acid-heat treatment of the sera before testing possibly increased sensitivity as compared with the untreated sera, and the interfering rheumatoid factor activity was eliminated.

Antigens, Fungal↗

Blunt trauma and liver abscess.

Three cases of pyogenic liver abscess following blunt trauma to the torso are described. The association between blunt trauma with liver contusion and the development of bacterial pyogenic liver abscess is explored. Reported series of liver abscess are reviewed. It is suggested that physicians look for the development of liver abscess in patients who have had major blunt trauma to the torso. Physicians should also inquire about blunt trauma in patients with documented pyogenic liver abscesses.

Abdominal Injuries↗

Bactericidal screening test for late complement component deficiencies or defects.

Congenital complement deficiency has been described in disseminated Neisseria infections. Its occurrences in humans with other kinds of infections have not been described. In the past, CH50 determinations have been used to detect these deficiencies, but this procedure is time consuming and cumbersome. A method of determining the presence of late component deficiencies or defects is described which is easy and inexpensive to perform. An agar pour plate with a serum-sensitive Escherichia coli strain is made, and 2.5-mm wells are put in the agar. Unknown fresh sera are used to fill the wells. An absence of a zone of bacterial growth inhibition around the well after incubation at 37 degrees C overnight indicates a late component defect or deficiency in the test serum. By applying this assay to 35 selected patients, four deficient patients were identified. One had a congenital C5 deficiency and three had C6 deficidencies. It is suggested that the assay be used as a screening test to study the relationship between congenital complement deficiencies and various kinds of infections, especially those caused by organisms which are partially serum sensitive.

Bacteriological Techniques↗

Clindamycin for colonization and infection by methicillin-resistant Staphylococcus aureus.

Effective antimicrobial therapy for infection or colonization by methicillin-resistant Staphylococcus aureus (MRSA) is very limited. In some institutions, the majority of strains remain susceptible to clindamycin in vitro. We report five patients with colonization or infection of varying severity caused by MRSA who had the organism successfully eradicated by clindamycin. In one patient who had an MRSA infection that persisted during vancomycin therapy clindamycin therapy was able to finally eradicate the organism. Clindamycin should be seriously considered as alternative therapy for colonization or infection by MRSA.

Aged↗

Vitamin K supplementation during prophylactic use of cefoperazone in urologic surgery.

Cefoperazone, an antibiotic commonly used for prophylaxis of infection, has been associated with hypoprothrombinemia and bleeding. To reduce the risk of bleeding, co-administration of vitamin K has been advised. We reassessed the need for vitamin K use in a retrospective analysis of 50 patients undergoing urologic procedures and who had received cefoperazone for three days to prevent infection. Eleven of 50 patients were given vitamin K because of liver or renal disease. Prothrombin time was not elevated in any of the 50 patients analyzed. We conclude that routine use of vitamin K with cefoperazone for perioperative prophylaxis of infection may be unwarranted in patients without identified risk for bleeding.

Aged↗

Effect of antibiotics on endotoxin release from gram-negative bacteria.

Antibiotics may inhibit bacterial growth or may kill bacteria by inhibiting cell wall synthesis or protein synthesis. The amount of endotoxin released during antibiotic action has been found to be clinically important. Nine antibiotics, representing seven classes, were studied for the amounts of endotoxin released during their action on susceptible strains of Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomonas aeruginosa. Staphylococcus aureus, which produces no endotoxin, was used as a control organism. Aztreonam induced the highest release of endotoxin, whereas other antibiotics such as imipenem and the quinolones induced the lowest release of endotoxin. Although the quantities of endotoxin released are not easily explained from the established mechanisms of antibiotic action, our findings may have implications for therapy of the acutely ill, septic patient in whom release of large quantities of endotoxin may be catastrophic.

Anti-Bacterial Agents↗

Penetration of newer cephalosporins into cerebrospinal fluid.

A review of the world literature on the penetration (ratio of concentrations of cerebrospinal fluid to concentrations of serum) and attainable antibiotic concentrations in the cerebrospinal fluid in humans for cefuroxime, cefoxitin, cefotaxime, ceftizoxime, cefmenoxime, cefamandole, cefoperazone, moxalactam, ceftazidime, and ceftriaxone indicates that, with the exceptions of cefamandole and cefoperazone, all agents appear equivalent. We conclude that the choice of cephalosporin for the treatment of acute bacterial meningitis should depend mainly on the potency of the agent for the specific meningeal pathogens in question. For the treatment of common meningeal pathogens (Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis) and for gram-negative bacilli, mainly Escherichia coli and Klebsiella (excluding Pseudomonas aeruginosa), the cefotaxime-ceftriaxone group of cephalosporins has accrued the most clinical experience and the most pharmacokinetic data, while for P. aeruginosa the major interest has centered on ceftazidime.

Animals↗

Antibiotic killing of bacteria: comparison of bacteria on surfaces and in liquid, growing and nongrowing.

The minimum inhibitory concentrations of antibiotics for bacterial pathogens are derived from broth suspensions (broth dilution) and from nutrient surfaces (agar dilution). These concentrations may not apply when bacteria are on a nonnutrient surface such as in a foreign body infection. We compared bacteria (Staphylococcus epidermidis and Escherichia coli) broth suspension MBCs with MBCs of the same bacteria when on a nonnutrient surface in broth the growing and nongrowing phases. Bacteria growing on cotton surfaces were much less susceptible to antibiotic killing than when freely suspended in the liquid nutrient. These results alone, independent of host factors, would explain the failure of antibiotics to eradicate infections involving bacteria on foreign body surfaces. The resistance of bacteria to antibiotic killing is not caused by a lack of antibiotic penetration to the site of the bacteria, but by an altered state of the bacteria when they are associated with a surface.

Anti-Bacterial Agents↗