Biomedical subjects
Publications and source records attributed to F Tecson-Tumang.
The monocyte plays a key role in the pathophysiology of AIDS and ARC. This preliminary report adds insight into monocyte activation associated with HIV seroconversion, by comparing recalcification times in healthy controls and HIV-positive patients.
During the first twelve months after ciprofloxacin was introduced for clinical use at our institution, 65 new patients were found to be either infected or colonized by methicillin-resistant Staphylococcus aureus (MRSA) which were also ciprofloxacin resistant (CR-MRSA). Only 18 of these patients (28%) had been previously exposed to this antibiotic. Nine (50%) of the 18 patients had received ciprofloxacin for treatment for a pathogen other than MRSA. Although the initial cases of colonization or infection with CR-MRSA can be directly related to ciprofloxacin use, many of the subsequent cases of colonization and infection were not the consequence of ciprofloxacin therapy but rather hospital transmission of existing CR-MRSA.
We describe an AIDS patient who had a recurrence of Pseudomonas meningitis to illustrate three points. First, the use of sulfamethoxazole-trimethoprim in AIDS patients for prophylaxis of Pneumocystis carinii pneumonia may cause the various body sites to be colonized with resistant species such as P aeruginosa. Second, Pseudomonas meningitis can recur in a patient with AIDS after a month of appropriate therapy. Finally, imipenem is a poor choice for Pseudomonas meningitis, even when alternative therapies appear much less attractive. High doses of imipenem should not be used for fear of seizures, and lower doses only produce resistant organisms in the CSF.
Thirty patients were treated for colonization or for skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus. Three treatment regimens were evaluated, each progressively more aggressive. Our regimen was 750 mg of ciprofloxacin twice daily for 5 days, the second regimen was 750 mg of ciprofloxacin twice daily for 10 to 14 days, and the final regimen was 750 mg of ciprofloxacin twice daily plus 300 mg of rifampin twice daily for 21 days. It appears that ciprofloxacin alone produced an initial eradication rate in at least one site in 50% of the patients, regardless of whether the treatment was for 5 or up to 14 days. All of the patients with eradication became recolonized within 1 week posttherapy. When rifampin was combined with ciprofloxacin, the eradication rate was 100% when the isolates were susceptible to both agents, and these patients remained free of methicillin-resistant S. aureus at 1-week and 1-month follow-ups.
In the past, vancomycin has been reported to cause renal failure during intravenous administration; however, more recently, such renal toxicity is alleged not to occur because of increased purity of the vancomycin preparations. In this study, 23 patients were prospectively examined during intravenous vancomycin administration for changes in renal function. Vancomycin was administered for an average of 15 days. The blood urea nitrogen (BUN) changes averaged +1.7 mg/dl and the creatinine changes averaged +0.06 mg/dl. Since the accuracy of the serum creatinine determination was +/- 0.3 mg/dl, clinically significant deterioration of renal function occurred in 4 patients or 17%. Even among these 4 patients with documented worsening of renal function, we suspect that deterioration was related to the infection being treated. With close monitoring of dosing, the propensity of vancomycin to cause nephrotoxicity may be less than once thought.
Eubacterium is a commensal of the human gastrointestinal tract. In rare instances this organism can become blood-borne. Nine cases of bacteremia were described and eight cases were found in the medical literature. Thirteen of the 17 cases (76%) had active gastrointestinal disease leading to the Eubacterium bacteremia. It is suggested that recovery of Eubacterium in blood culture should alert the clinician to the possibility of active gastrointestinal disease including occult neoplasms.
Twenty-seven isolates of Staphylococcus aureus were found to be resistant to methicillin, nafcillin, tobramycin, gentamicin, amikacin, cefoxitin, clindamycin, erythromycin and chloramphenicol by disc diffusion testing and tube dilution studies; they were sensitive to cefamandole, cephalothin and vancomycin by disc testing. A discrepancy between minimum inhibitory and bactericidal concentrations was noted for the cephalosporins which was not appreciated on disc testing. All isolates were very sensitive to rifampin (minimum bactericidal concentration 0.3 mg/l). All isolates were susceptible to phage type 83A. A subpopulation of variant small-colony forms of Staphylococcus aureus was recovered when superinhibitory amounts of aminoglycosides and methicillin were used. The variant Staphylococcus aureus strains retained the same antibiotic susceptibility patterns and phage type as their parent strain of Staphylococcus aureus. Further studies are in progress concerning these isolates and their impact on the hospital flora at our institution.
A case of purulent meningitis in an adult caused by Streptococcus MG-intermedius, also known as Streptococcus milleri, is described. The intriguing taxonomical history of this organism and its association with mycoplasma pneumoniae pulmonary infections is reviewed. The incidence of central nervous system infections due to this organism is also discussed.
The effect of vegetation size upon the concentration of antibiotic within various points of a fibrin-clot heart valve vegetation such as ones found in bacterial endocarditis was examined. A mathematical model based upon Fick's second law of diffusion was developed and solved on a PDP-II computer. The antibiotic was assumed to have a half-life of 30 min and intermittently injected intravenously every 4 h. After 5 simulated antibiotic doses, peak and trough levels of the antibiotic near the center of the vegetations of sizes 0.5, 1.0, 2.0 cm were, respectively, 37 and 3%, 22 and 15%, and 18 and 18% of the free serum antibiotic concentration. This model can be used to estimate antibiotic levels in different areas of a valvular vegetation.
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.
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.