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Biomedical subjects

D R Schaberg

Publications and source records attributed to D R Schaberg.

At least 37 records · Page 2Linked to original sources
PubMed1990

Neisseria mucosa endocarditis.

A case of Neisseria mucosa tricuspid valve endocarditis in an intravenous drug abuser is described. The patient was treated initially with intravenous penicillin G followed by oral penicillin VK but relapsed. He was cured after 4 weeks of combined therapy with penicillin G and gentamicin. In vitro synergy studies performed on the patient's and two other isolates revealed synergy in all three. Thus, combination therapy is recommended for treatment of recalcitrant cases of bacterial endocarditis caused by N. mucosa.

Adult↗
PubMed1990

Efficacy of ampicillin versus trimethoprim-sulfamethoxazole in a mouse model of lethal enterococcal peritonitis.

Lethal enterococcal peritonitis in mice was used to compare trimethoprim-sulfamethoxazole (TMP-SMX) therapy with ampicillin therapy. Peritoneal fluid showed a 10(3)-CFU decrease in enterococci with ampicillin compared with TMP-SMX. Mortality of the untreated mice was 100%, compared with 40% for ampicillin and 95% for TMP-SMX, despite adequately measured levels in serum and peritoneal fluid.

Ampicillin↗
PubMed1990

Increasing resistance of Staphylococcus aureus to ciprofloxacin.

We demonstrated the marked emergence of resistance to ciprofloxacin among Staphylococcus arueus strains isolated at the Ann Arbor Veterans Administration Medical Center. All S. aureus isolates tested from 1984 to 1985 were susceptible, whereas 55.1% of methicillin-resistant and 2.5% of methicillin-susceptible strains from 1989 had high-level resistance to ciprofloxacin.

Ciprofloxacin↗
PubMed1990

Artery, periarterial adipose tissue, and blood microbiology during vascular reconstructive surgery: perioperative and early postoperative observations.

The presence and clinical significance of bacteria in the arterial wall, periarterial adipose tissue, and blood samples acquired during elective vascular operations were assessed in this study. Specimens were obtained from a random series of 84 patients (56 men, 28 women) undergoing 75 primary and 9 secondary arterial reconstructions. Operations performed most frequently included abdominal aortic aneurysmectomy (42), aortofemoral bypass reconstruction (15), and lower extremity bypass surgery for occlusive disease (7). Perioperative antibiotics were administered to all but one patient. A sample of artery, adjacent adipose tissue, and blood were obtained for microbial analysis during the vascular anastomosis or arteriotomy. This yielded a total of 152 artery, 139 adipose tissue, and 129 blood samples for study. Each specimen was divided and placed in blood agar plates, thioglycolate broth, and brain-heart infusion broth. Tissues yielding growth of the same organism(s) in two or more different media were considered positive for the presence of bacteria. Bacteria were present in at least one of the three tissues studied in 32/84 patients (38%). The frequency of positive cultures in primary (29/75, 39%) and secondary procedures (3/9, 33%) were similar. One positive culture site occurred in 26/32 (81%) patients, two positive culture sites existed in 5/32 (16%) patients, and three positive sites were found in 1/22 (3%) patients. Eighteen individual artery (18/152, 12%) and 19 adipose tissue samples (19/139, 14%) harbored bacteria, whereas only two blood cultures were positive (2/129, 2%). Organisms identified included coagulase-negative staphylococci (71%), gamma-streptococci (7%), diphtheroids (7%), Micrococcus (5%), alpha-streptococci (5%), Staphylococcus aureus (2%), and Pseudomonas picketti (2%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1988

Enterococcal infections: an increasing problem in hospitalized patients.

We studied 157 episodes of infection or colonization with enterococci in 122 patients over a six-month period. One hundred twelve episodes (71.3%) occurred in patients over age 60 years. The most common sites for isolation of enterococci were the urinary tract, and bone and soft tissue. Nosocomial acquisition of enterococci occurred in 74.7% of all infections, and an additional 21% of episodes occurred in patients who had been transferred from another hospital or were regularly seen in the clinic. The overall mortality was 19.6%; 71.4% of those with bacteremia died. Enterococci appear to be significant pathogens, especially in older men in veterans' acute care hospitals and nursing home care units.

Aged↗
PubMed1988

Epidemiology of Clostridium difficile colonization in newborns: results using a bacteriophage and bacteriocin typing system.

We used a typing system based on bacteriophage and bacteriocin susceptibility to study the epidemiology of Clostridium difficile colonization of newborn infants. C. difficile was found in the stools of 30 (16.0%) of 187 infants who were screened. Increased length of stay in the nursery (P less than .001) and delivery by cesarian section (P less than .001) were associated with higher rates of colonization. The isolates initially detected from the environment and the infants were strain B1811-1700. Strain B1537/Cld7 became the predominant isolate obtained from the infants; positive cultures were also obtained from the environment and the hands of personnel who worked in the nursery and had strain B1537/Cld7. Our results suggest that the infants acquired C. difficile through transfer from the hands of hospital staff.

Bacterial Proteins↗
PubMed1988

Enterococcal superinfection in patients treated with ciprofloxacin.

Two patients developed serious enterococcal superinfection following therapy with intravenous ciprofloxacin. The strains causing bacteraemia were susceptible to low concentrations of ciprofloxacin when tested at a standard inoculum. However, at an inoculum of 1 X 10(7) cfu/ml they were resistant to high concentrations of ciprofloxacin. Our data suggest that ciprofloxacin should not be used to treat patients with serious enterococcal infection and that patients treated with ciprofloxacin should be monitored carefully for the development of enterococcal superinfection.

Adult↗
PubMed1988

Acquisition of Clostridium difficile from the hospital environment.

An outbreak of antibiotic-associated colitis that occurred on a ward of a Michigan hospital during February-April, 1984, was studied by bacteriophage-bacteriocin typing. Stools from the seven involved patients yielded Clostridium difficile isolates of types B1537 or Cld7;B1537. C. difficile was recovered from 31.4% of environmental cultures obtained on the ward, and the majority of isolates were types B1537 or Cld7;B1537. When the ward was disinfected with unbuffered hypochlorite (500 parts per million (ppm) available chlorine), surface contamination decreased to 21% of initial levels and the outbreak subsequently ended. Phosphate buffered hypochlorite (1,600 ppm available chlorine, pH 7.6) was even more effective; its use resulted in a 98% reduction in surface contamination. These findings suggest that environmental contamination with C. difficile is important in the epidemiology of antibiotic-associated colitis, and that hypochlorite is effective in eliminating C. difficile from the hospital environment.

Clostridium↗
PubMed1988

The pathogenesis of spinal epidural abscess: microangiographic studies in an experimental model.

An experimental model of spinal epidural abscess was developed in rabbits by injecting Staphylococcus aureus into the posterior thoracolumbar epidural space. This model has been shown to reproduce the neurological, bacteriological, and radiological aspects of the human disease. In this study, the effect of the infectious epidural mass on the vasculature of the spinal cord in paraplegic rabbits was studied using microangiographic techniques. The normal vascular anatomy of the rabbit spinal cord was defined in control experiments. Vascular proliferation was demonstrated in the epidural space surrounding the abscesses. Anterior and paired posterior spinal arteries remained patent in paraplegic rabbits with mild or moderate spinal cord compression and in some cases of severe compression. In animals with severe compression, the anterior epidural venous plexus remained patent, but the dorsal spinal vein was occluded. Occlusion of perforating arteries occurred only with extreme spinal cord compression. These data indicate that the initial neurological deficit associated with experimental spinal epidural abscess is not due to vascular thrombosis.

Abscess↗
PubMed1987

Fever in hospitalized patients. With special reference to the medical service.

Fever (oral temperature of 38 degrees C or more on two or more consecutive days) during the hospital stay of 4,065 patients admitted to Grady Memorial Hospital during an 11-week period was studied. At least one episode of fever occurred in 1,194 patients (29 percent). Rates of fever were highest on medical and surgical services. Review of 341 episodes of fever in 302 patients on the medical service identified a single potential cause in 56 percent. Multiple factors were present in 26 percent, and no potential causes were found in 18 percent. Of 390 factors identified, 44 percent were community-acquired infections, 9 percent were nosocomial infections, 20 percent possibly involved infection, and 26 percent were noninfectious processes. Fever is a frequent finding in hospitalized patients. Both infectious and noninfectious processes play important roles. Determining the cause of fever is complicated by the multiplicity of possible causes.

Cross Infection↗
PubMed1987

High-level aminoglycoside-resistant enterococci. Colonization of nursing home and acute care hospital patients.

Enterococci with high-level resistance (HLR) to gentamicin sulfate and other aminoglycosides have emerged as pathogens in recent years. More than half of all current isolates of enterococci at the Ann Arbor (Mich) Veterans Administration (VA) Medical Center are HLR strains. We determined the rate of colonization with HLR enterococci in patients in the acute care hospital, the attached nursing home, and a private nursing home. We also studied the factors related to colonization and the molecular relatedness of strains of HLR enterococci in these settings. In the VA facilities, 47.4% of patients in the nursing home and 36.1% of patients in the acute care hospital were colonized, compared with a 4.3% colonization rate in the private nursing home. Intravenous or Foley catheters and bedridden status were associated with colonization in the acute care setting; the need for advanced nursing care and prior antibiotic therapy were associated with colonization in the nursing home. Environmental surfaces were contaminated with HLR enterococci in both VA settings. Plasmid analysis of HLR strains revealed identity between both patient and environmental strains in the nursing home care unit and the acute care hospital. Nursing home patients, with their high rate of colonization with HLR enterococci and their frequent movement into the acute care hospital, may play a role as a reservoir for subsequent transmission of HLR enterococci.

Cross Infection↗
PubMed1987

The emergence of resistance to ciprofloxacin during treatment of experimental Staphylococcus aureus endocarditis.

The efficacy of ciprofloxacin was compared with that of vancomycin in the rabbit model of methicillin-susceptible Staphylococcus aureus endocarditis. Animals were treated with ciprofloxacin, 25 mg/kg iv every 8 h or vancomycin, 17.5 mg/kg iv every 6 h, for 3, 6, or 9 days. Both drugs were found to be equally effective in the therapy of this infection, but the degree of reduction in bacterial counts was less than expected on the basis of previous studies. Additionally, resistance to ciprofloxacin in the test strain of S. aureus was seen to emerge in 12.5% of animals that received the drug. This raises concern about the use of ciprofloxacin as a single agent in the therapy of humans with serious systemic S. aureus infections.

Animals↗
PubMed1987

Staphylococcus aureus meningitis: a broad-based epidemiologic study.

In an effort to ascertain important epidemiologic and prognostic risk factors, we analyzed 33 cases of Staphylococcus aureus meningitis occurring over an 8-year period (1976 to 1984). Staphylococcus aureus caused 6% of all bacterial meningitis at our University Hospital. Fifty percent of cases were pediatric and included 7 newborn infants, of whom 71% were either premature or had low birth weight. Major underlying diseases were: central nervous system (CNS) disorders (55%), endocarditis (21%, predominantly intravenous drug abusers), other sites of infection (27%), and prematurity (24%). Fifty-seven percent of patients were bacteremic and 41% of those had concomitant bacteriuria. Hypoglycorrhachia was present in 27% of cases, positive cerebrospinal fluid (CSF) Gram stain in 20%, disseminated intravascular coagulation (DIC) in 19%, and methicillin-resistant organisms in 18%. Cerebrospinal fluid cultures remained positive for a protracted period (mean, 6.7 days) regardless of the presence or absence of a CNS shunt. Overall mortality was 21%. Favorable outcomes were associated with the eventual presence of sterile CSF (15.4% vs. 100% mortality) and the removal of foreign bodies (10% vs. 67% mortality). Mortality was also associated (p less than 0.5) with the presence of diabetes mellitus, age greater than 60, obtundation or coma on presentation, bacteremia, or DIC. Cure correlated (p less than .05) with CNS shunt-associated infections, age less than 1, normal neurologic examinations on presentation, or the absence of DIC or bacteremia.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1987

Bordetella bronchiseptica pneumonia in a patient with chronic lymphocytic leukemia.

This case report describes two episodes of pneumonia caused by Bordetella bronchiseptica in a patient with chronic lymphocytic leukemia. There was discrepancy between the in vitro sensitivity testing of the organism and subsequent clinical response to several antimicrobial agents. Human infection with B bronchiseptica is almost always associated with severe underlying disease and contact with an appropriate animal reservoir.

Aged↗
PubMed1987

Ciprofloxacin versus vancomycin in the therapy of experimental methicillin-resistant Staphylococcus aureus endocarditis.

We compared the efficacy of ciprofloxacin with that of vancomycin by using the rabbit model of methicillin-resistant Staphylococcus aureus endocarditis. Endocarditis was treated with ciprofloxacin (25 mg/kg [body weight] intravenously every 8 h) or vancomycin (17.5 mg/kg intravenously every 6 h) for 3 days. Vancomycin and ciprofloxacin were equally efficacious in clearing bacteremia. Both reduced vegetation bacterial counts by 5 log10 CFU/g and renal and splenic bacterial counts by more than 3 log10 CFU/g as compared with untreated control rabbits after 26 h of infection (P less than 0.001). Both antimicrobial agents were able to eradicate the infectious process in an equivalent proportion of animals. No methicillin-resistant S. aureus that was recovered from ciprofloxacin-treated rabbits developed resistance to ciprofloxacin during therapy. Peak concentrations of ciprofloxacin in the sera of rabbits with endocarditis were significantly higher than those predicted by single-dose studies in uninfected rabbits. This finding was likely due to changes in the pharmacokinetics of the drug with multiple dosing and in infected versus uninfected rabbits. This study demonstrated that intravenously administered ciprofloxacin is as efficacious as vancomycin is in an in vivo model of a serious systemic methicillin-resistant S. aureus infection.

Animals↗
PubMed1987

Altered pharmacokinetic disposition of ciprofloxacin and vancomycin after single and multiple doses in rabbits.

The pharmacokinetic disposition of vancomycin and ciprofloxacin was assessed in rabbits before the efficacy of these compounds in experimental staphylococcal endocarditis was compared. Ciprofloxacin was given in single intravenous bolus doses of 25 and 35 mg/kg and also in a multiple-dose regimen of 35 mg/kg every 6 h. Vancomycin was given in a similar manner in single doses of 17.5 and 25 mg/kg and in a multiple-dose regimen of 17.5 mg/kg every 6 h. Serum was sampled frequently after injections and analyzed by microbiologic assay for drug concentration. The pharmacokinetic parameters of clearance and steady-state volume of distribution were calculated by compartment-independent methods. These studies revealed that clearance of ciprofloxacin was reduced significantly after multiple doses (7.42 +/- 0.85 [standard deviation] versus 6.09 +/- 0.71 liters/h, P less than 0.01). Although the half-life and volume of distribution increased after multiple dosing, the differences were not statistically significant. The disposition of vancomycin following single doses was significantly altered after the 25-mg/kg dose compared with the 17.5-mg/kg dose. Half-life, clearance, and volume of distribution changed from 1.27 +/- 0.2 to 1.60 +/- 0.21 h (P less than 0.05), 0.54 +/- 0.05 to 0.39 +/- 0.04 liters/h (P less than 0.01), and 0.37 +/- 0.04 to 0.31 +/- 0.03 liters/kg (P less than 0.05), respectively. The disposition of ciprofloxacin was not altered with increases in dose size, and the disposition of vancomycin was not altered after multiple doses. If such alterations in the pharmacokinetic disposition of antimicrobial agents are unanticipated, the higher and more prolonged than expected serum concentrations may have an effect on the outcome of experimental infections.

Animals↗