Biomedical subjects

R R Muder

Publications and source records attributed to R R Muder.

At least 55 records · Page 3Linked to original sources

PubMed1992

Staphylococcus epidermidis bacteremia from transfusion of contaminated platelets: application of bacterial DNA analysis.

Septicemia is a rare complication of platelet transfusion. A case is reported of transfusion-associated septicemia in a 66-year-old man who received a 10-unit pool of platelets. During transfusion, he experienced rigors, wheezing, dyspnea, and fever. A total of four blood cultures drawn 10 and 36 hours after discontinuation of the transfusion grew Staphylococcus epidermidis. Culture of the residual platelet pool yielded S. epidermidis with a colony count of 10(5) organisms per mL. Strain identity of all four blood isolates and the platelet pool isolate was confirmed by gel electrophoresis of EcoRI and HindIII restriction digests of whole-cell DNA. There have been 31 prior reported cases of platelet transfusion-associated septicemia, of which 9 have been caused by coagulase-negative staphylococci. Systemic reactions to platelet transfusions should prompt consideration of transfusion-associated bacteremia as the cause.

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PubMed1992

Molecular epidemiology of endemic ciprofloxacin-susceptible and -resistant Enterobacteriaceae.

OBJECTIVES: To elucidate the epidemiology of widespread ciprofloxacin resistance in our Veterans Affairs medical center using whole cell DNA analysis. DESIGN: In vitro study of ciprofloxacin resistant and susceptible Enterobacteriaceae isolated during the course of a clinical epidemiologic study of quinolone resistance. SETTING: Veterans Affairs Medical Center with acute care and long-term care divisions. RESULTS: We examined 40 ciprofloxacin-resistant strains of Serratia marcescens, Proteus mirabilis, and Providencia stuartii using restriction endonuclease analysis of whole cell DNA and compared them with concomitantly isolated ciprofloxacin sensitive strains. We sought to determine whether resistant strains were identical to susceptible strains, indicating in vivo emergence of resistant strains from susceptible strains, and whether resistant strains were shared among patients. All 26 ciprofloxacin-resistant S marcescens isolates shared a single ecoRI restriction pattern. Multiple patterns were seen in the ciprofloxacin-susceptible S marcescens isolates; however, several isolates had a pattern matching that of the resistant isolates. Similar results were seen among the P mirabilis isolates. Three different ecoRI patterns were found among the ciprofloxacin-resistant P stuartii isolates; none matched those found among the susceptible isolates. The frequency of spontaneous emergence of ciprofloxacin resistance in susceptible S marcescens strains with restriction pattern matching that of the resistant strains was significantly higher than that of nonmatching strains. CONCLUSIONS: Ciprofloxacin-resistant strains of Enterobacteriaceae became widespread within a short period of time. Resistant strains of S marcescens and P mirabilis arose from endemic susceptible strains. The resistant strain of S marcescens appeared to arise from a susceptible strain with a relatively high frequency of spontaneous ciprofloxacin resistance.

Case-Control Studies↗

PubMed1992

Group A streptococcal meningitis.

Meningitis due to group A streptococci occurs uncommonly. We report two cases, one in a patient with otitis media and the other in a patient with bullous pemphigoid. Nineteen cases in the English-language literature from the past decade plus our two cases are reviewed. In 17 patients, an associated illness was present, most often otitis media or pharyngitis. When performed, gram staining of the cerebrospinal fluid and cultures of blood usually yielded organisms. Cerebrospinal fluid was acellular in two patients. Of 21 patients, 20 survived. Antibiotic therapy, which consisted of penicillin for most patients, was effective. Ceftriaxone may be an alternative agent. Neurologic sequelae occurred more often in children than in adults.

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PubMed1992

Bacteremia in a long-term-care facility: a five-year prospective study of 163 consecutive episodes.

The clinical features, microbiological characteristics, and outcomes of 163 episodes of bacteremia occurring at a long-term-care facility were evaluated. The rate of nosocomial bacteremia increased from 0.20 to 0.36 cases/1,000 patient-days from 1985 to 1989; there was a parallel increase in the rate of all nosocomial infections combined. Bacteremia was documented in 6.5% of all hospital-acquired infections. The majority of isolates were gram-negative, and Providencia stuartii was the most common gram-negative species. Staphylococcus aureus was the most frequent isolate; one-third of S. aureus strains were resistant to methicillin. Bacteremia was polymicrobial in 36 episodes (22%), 14 of which involved an enterococcal species. Portals of entry included the urinary tract (55%), the respiratory tract (11%), and soft tissue (9%). Overall mortality was 21.5%. Death was significantly associated with residence on the intermediate-care unit, the presence of a respiratory infection, a change in mental status, and relatively recent admission. Optimal management of bacterial infection in a long-term-care setting requires the availability of blood culture results. Initial decisions about antibiotic therapy should be made in light of the likelihood of infection with multiresistant organisms and of polymicrobial infection.

Adult↗

PubMed1992

Entering first-year residents' experiences and knowledge of infection control of hepatitis B and HIV, at five university-affiliated hospitals.

In 1990, the authors surveyed 149 entering first-year residents at five university-affiliated hospitals concerning the residents' experiences and knowledge of infection control. Sixty residents (40%) had experienced a needlestick injury during medical school, but only 35 of these residents (58%) had reported the mishap. One hundred thirty-nine residents (93%) had received the hepatitis B vaccine. Of those 60 who had experienced a needlestick injury, 57 (95%) had received the vaccine. Of the 149 residents, 111 (74%) reported having received instructions in universal precautions, as advocated by the Centers for Disease Control. There was a trend for residents who had received the vaccine also to have been instructed in universal precautions. Regarding the residents' knowledge of infection control, there was no statistically significant difference between the responses of those who had been instructed in universal precautions and those who had not. The authors conclude that students are at risk for needlestick injuries; however, underreporting is frequent.

Educational Measurement↗

PubMed1992

Prospective observational study of Klebsiella bacteremia in 230 patients: outcome for antibiotic combinations versus monotherapy.

Combination antimicrobial agent therapy has been advocated for treatment of gram-negative bacteremia, including that caused by Klebsiella spp. We performed a prospective, observational, 10-hospital collaborative study to evaluate the efficacy of antibiotic combination therapy versus that of monotherapy for 230 consecutive patients with Klebsiella bacteremia. The species involved were K. pneumoniae (82%), K. oxytoca (15%), and K. ozaenae (0.4%). Of the bacteremias, 26% were polymicrobial in nature. A total of 53% of cases were nosocomial infections. The most common portals were the urinary tract (28%), biliary tract (12%), lung (10%), and abdomen (9%). Some 49 and 51% of the patients had received monotherapy and antibiotic combination therapy (beta-lactam plus aminoglycoside), respectively; 14-day mortalities in the two groups were 20 and 18%, respectively. However, for the subgroup of patients who experienced hypotension within 72 h prior to or on the day of the positive blood culture, those patients who received combination therapy experienced significantly lower mortality (24%) than did those who received monotherapy (50%). We conclude that monotherapy with an antibiotic that is active in vitro against Klebsiella (beta-lactam or aminoglycoside) is sufficient therapy for less severely ill patients (immunocompetent, urinary tract portal, mentally alert, normal vital signs). On the other hand, for severely ill patients who experience hypotension, antibiotic combination therapy with a beta-lactam and an aminoglycoside agent is preferred.

Adolescent↗

PubMed1992

Addition of rifampin to combination antibiotic therapy for Pseudomonas aeruginosa bacteremia: prospective trial using the Zelen protocol.

A multicenter, prospective randomized trial was conducted to determine if the addition of rifampin to a combination therapy of an antipseudomonal beta-lactam agent and aminoglycoside improves the outcome of patients with Pseudomonas aeruginosa bacteremia. The Zelen protocol for randomized-consent design was used. Consent was sought only from patients randomized to the experimental therapy (rifampin+). If the experimental therapy was refused, the patient would then receive the standard combination therapy (control); however, when outcome was evaluated, all patients randomized to the rifampin+ group, including those that declined rifampin, were compared with the control group. One hundred twenty-one consecutive hospitalized patients with positive blood cultures for P. aeruginosa were enrolled. Entry was stratified for prior use of empiric antipseudomonal antibiotics, neutropenia, severity of illness, and presence of pneumonia. Fifty-eight patients were randomized to receive rifampin (600 mg orally every 8 h for the first 72 h and then every 12 h for a total of 10 days) plus a beta-lactam agent plus an aminoglycoside. Sixty-three received the standard therapy of a beta-lactam plus an aminoglycoside agent (control). Bacteriologic cure occurred significantly more frequently in patients randomized to the rifampin+ regimen. Breakthrough or relapsing bacteremias occurred in 2% of the three-drug (rifampin+) group, compared with 14% for the two-drug (standard therapy) group. Despite this favorable trend in bacteriological response, no significant differences in survival were seen for the two treatment groups. Rifamycin derivatives warrant further clinical study as antipseudomonal agents. The Zelen protocol appears well suited for comparative trials of antimicrobial agents.

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PubMed1992

Isolation of Legionella pneumophila serogroup 5 from empyema following esophageal perforation. Source of the organism and mode of transmission.

A patient undergoing esophageal dilatation for carcinoma of the esophagus suffered esophageal perforation and development of an empyema. Culture of pleural fluid yielded multiple organisms, including Legionella pneumophila serogroup 5. Epidemiologic investigation showed that the source of L pneumophila was a tap used by the nursing personnel to fill patients' water pitchers. Whole-cell restriction endonuclease analysis of DNA from the clinical and environmental isolates of L pneumophila serogroup 5 yielded identical patterns. Our findings suggest that L pneumophila was acquired by the patient at least 12 h prior to the procedure causing the esophageal perforation and empyema, suggesting that the organism can persist in an infectious form in the upper aerodigestive tract.

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PubMed1991

Methicillin-resistant staphylococcal colonization and infection in a long-term care facility.

OBJECTIVE: To determine the natural history of colonization by methicillin-resistant Staphylococcus aureus (MRSA) among patients in a long-term care facility. We specifically sought to determine if MRSA colonization was predictive of subsequent infection. DESIGN: Cohort study. SETTING: Long-term Veterans Affairs Medical Center. PATIENTS: A total of 197 patients residing on two units were followed with regular surveillance cultures of the anterior nares. MAIN OUTCOME MEASUREMENT: The development of staphylococcal infection. RESULTS: Thirty-two patients were persistent carriers of MRSA and 44 were persistent carriers of methicillin-susceptible strains (MSSA). Twenty-five percent of MRSA carriers had an episode of staphylococcal infection compared with 4% of MSSA carriers and 4.5% of non-carriers (P less than 0.01; relative risk 3.8; 95% CI, 2.0 to 6.4). The rate of development of infection among MRSA carriers was 15% for every 100 days of carriage. Using logistic regression analysis, persistent MRSA carriage was the most significant predictor of infection (P less than 0.001; odds ratio, 3.7). Seventy-three percent of all MRSA infections occurred among MRSA carriers. Isolates of MRSA from 7 patients were typed. Colonizing and infecting strains had the same phage type in all 7 patients and the same pattern of plasmid EcoRI restriction endonuclease fragments in 5 patients. CONCLUSIONS: Colonization of the anterior nares by MRSA predicts the development of staphylococcal infection in long-term care patients; most infections arise from endogenously carried strains. Colonization by MRSA indicates a significantly greater risk for infection than does colonization by MSSA. The results offer a theoretic rationale for reduction in MRSA infections by interventions aimed at eliminating the carrier state.

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PubMed1991

Prevalence of nosocomial infection in long-term-care Veterans Administration medical centers.

Prevention and control of nosocomial infections are major goals of institutional risk-management programs. However, variations in criteria and denominator parameters make comparison of rates across settings difficult. This study addressed those problems by reporting criteria used to identify infections and applying the same denominator across long-term-care facilities. Findings demonstrated a 9.8% prevalence rate for nosocomial infections in four long-term-care VA facilities. Most of the identified infections were consistent with Centers for Disease Control definitions of nosocomial infections. The most frequent indicators of nosocomial infections that did not fully meet those definitions were (1) documented symptoms, (2) antibiotic therapy, and (3) physician diagnosis.

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PubMed1991

Klebsiella pneumonia in the modern era: clinicoradiographic correlations.

A classic clinical and radiographic picture of Klebsiella pneumonia has emerged in the literature. Patients are typically male, older than 48 years, and have a history of chronic alcoholism. The majority of these pneumonias are community acquired. Bulging interlobar fissures and cavitation are radiographic findings said to be distinctive for Klebsiella pneumonia. We prospectively studied 15 cases of bacteremically proven Klebsiella pneumonia and found clinical and radiographic features strikingly different from those described in the literature. Immunosuppression (from corticosteroids, cytotoxic chemotherapy, neutropenia, hematologic malignancy, and transplantation) now rivals alcoholism as the primary risk factor. Cases tended to be nosocomial rather than community acquired. Neither bulging interlobar fissure nor cavitation was seen in any case. The right upper lobe was involved in 11 of our 15 cases. Pneumonia due to Klebsiella oxytoca was more likely to be isolated from patients with bilateral infiltrates, while Klebsiella pneumoniae was more likely in patients with unilateral infiltrates.

Alcoholism↗

PubMed1991

Association with prior fluoroquinolone therapy of widespread ciprofloxacin resistance among gram-negative isolates in a Veterans Affairs medical center.

We performed a case-control study of risk factors for the acquisition of ciprofloxacin-resistant gram-negative isolates in a Veterans Affairs medical center. Sixty-five patients with resistant isolates and 50 control patients were identified. Prior fluoroquinolone use was significantly more frequent among patients with resistant isolates than it was among controls (58 versus 20%; P = 0.0001). The association with prior quinolone use was stronger in the long-term-care division (81 versus 32%; P = 0.0005) than it was in the acute-care division (29 versus 0%; P = 0.015). On multivariate analysis, prior receipt of a fluoroquinolone was the single most significant risk factor for isolation of a ciprofloxacin-resistant gram-negative organism (P = 0.0001).

Anti-Infective Agents↗

PubMed1990

Antibody response to pneumococcal polysaccharide vaccine in myasthenia gravis: effect of therapeutic plasmapheresis.

The removal of specific antibody in experimental animals has been reported to result in a subsequent increase in antibody to levels equal to (rebound) or exceeding those existing prior to removal (overshoot). Anecdotal reports suggest that rebound antibody synthesis after plasmapheresis may occur in humans with autoimmune disorders. We measured the antibody response to 12 pneumococcal polysaccharide antigens in patients with myasthenia gravis (MG) receiving a variety of therapies in order to determine whether the T-cell-independent IgG response to these antigens was augmented by plasmapheresis. MG patients receiving no immunotherapy or receiving prednisone had pre- and post-immunization titers similar to those of control patients. MG patients receiving prednisone and chronic plasmapheresis had higher pre-immunization titers than did other patient groups and had significantly higher post-immunization titers against multiple pneumococcal serogroups. Aggregate post-immunization geometric mean titers were more than three-fold higher in the plasmapheresis group as compared with other MG treatment groups. Enhancement of antibody response by plasmapheresis was abolished by the concomitant administration of azathioprine. Antibody rebound and overshoot after antibody removal may have important implications for the therapy of immune disorders by plasmapheresis.

Adult↗

PubMed1990

New and emerging etiologies for community-acquired pneumonia with implications for therapy. A prospective multicenter study of 359 cases.

Three hundred fifty-nine consecutive patients with community-acquired pneumonia admitted to university, community, and VA hospitals underwent a standardized evaluation, including specialized tests for Legionella spp. and Chlamydia pneumoniae (TWAR). The most common underlying illnesses were immunosuppression (36.3%), chronic obstructive pulmonary disease (32.4%), and malignancy (28.4%). The most frequent etiologic agents were Streptococcus pneumoniae (15.3%) and Hemophilus influenzae (10.9%). Surprisingly, Legionella spp. and C. pneumoniae were the third and fourth most frequent etiologies at 6.7% and 6.1%, respectively. Aerobic gram-negative pneumonias were relatively uncommon causes of pneumonia despite the fact that empiric broad-spectrum combination antibiotic therapy is so often directed at this subgroup. In 32.9%, the etiology was undetermined. Antibiotic administration before admission was significantly associated with undetermined etiology (p = 0.0003). There were no distinctive clinical features found to be diagnostic for any etiologic agent, although high fever occurred more frequently in Legionnaires' disease. Clinical manifestations for C. pneumoniae were generally mild, although 38% of patients had mental status changes. Mortality was highest for Staphylococcus aureus (50%) and lowest for C. pneumoniae (4.5%) and Mycoplasma pneumoniae (0%). We document that specialized laboratory testing for C. pneumoniae and Legionella spp. should be more widely used rather than reserved for cases not responding to standard therapy. Furthermore, realization that C. pneumoniae and Legionella spp. are common etiologies for community-acquired pneumonia should affect empiric antibiotic prescription.

Adolescent↗

PubMed1990

Multiple-dose pharmacokinetics of concurrent oral ciprofloxacin and rifampin therapy in elderly patients.

The purpose of this clinical study was to investigate the influence of concomitant drug therapy with ciprofloxacin and rifampin on the individual pharmacokinetic profile of each agent in elderly patients. Twelve nursing home patients (age, 74 +/- 7 years), colonized with methicillin-resistant Staphylococcus aureus, were randomized to receive 14-day therapy with oral ciprofloxacin (750 mg every 12 h) (group A; n = 6) or ciprofloxacin (750 mg every 12 h) and oral rifampin (300 mg every 12 h) (group B; n = 6). Serial blood samples were obtained from 0 to 12 h following ciprofloxacin doses 1 and 13 and from 0 to 36 h after the last ciprofloxacin dose. No significant differences (P greater than 0.05) were found between or within groups in any pharmacokinetic parameter. The mean ciprofloxacin oral clearance values were 0.35 +/- 0.06, 0.41 +/- 0.15, and 0.38 +/- 0.11 liter/h per kg for doses 1, 13, and 28, respectively, in group A patients. The mean oral clearance values in group B patients for the respective doses were 0.53 +/- 0.36, 0.32 +/- 0.13, and 0.36 +/- 0.17 liter/h per kg. Likewise, no significant differences (P greater than 0.05) in rifampin pharmacokinetic parameters were found when compared with historical controls. These data suggest that ciprofloxacin and rifampin may be given concomitantly in standard clinical dosing regimens. The combination results in therapeutic levels of both drugs and appears to be safe for administration to elderly nursing home patients.

Administration, Oral↗

PubMed1990

Fever, pulmonary infiltrates, and pleural effusion following acyclovir therapy for herpes zoster ophthalmicus.

A 71-year-old man presented with herpes zoster ophthalmicus and ocular involvement. Following the institution of intravenous therapy with acyclovir, the patient developed fever, hemoptysis, and a pleural friction rub. A ventilation-perfusion lung scan showed no defects; roentgenograms showed bilateral infiltrates and a left-sided pleural effusion. The fever abated promptly following discontinuation of acyclovir, and radiographic abnormalities resolved over ten days. No other anti-infective therapy was given. To our knowledge, the syndrome of fever, pulmonary infiltrates, and pleural effusion following use of acyclovir has not been previously reported.

Acyclovir↗

PubMed1990

Conjunctivitis associated with methicillin-resistant Staphylococcus aureus in a long-term-care facility.

PURPOSE: To determine the clinical characteristics of conjunctivitis associated with methicillin-resistant Staphylococcus aureus (MRSA) in a long-term-care facility. PATIENTS AND METHODS: We followed 20 episodes of MRSA-associated conjunctivitis in 19 patients occurring over a three-year period in a 432-bed long-term-care facility. RESULTS: The clinical picture was that of a purulent conjunctivitis from which MRSA was isolated on culture. Seventeen patients had severe, pre-existing neurologic impairment. Nine were colonized by MRSA before the onset of conjunctivitis. Seven of eight patients treated with oral ciprofloxacin and all eight patients treated with topical vancomycin showed clinical resolution of conjunctivitis. Persistence of MRSA colonization at a variety of anatomic sites was noted after therapy following 14 episodes. CONCLUSION: MRSA-associated conjunctivitis in our long-term-care facility was notable for its occurrence in patients with severe neurologic disease. Both oral ciprofloxacin and topical vancomycin therapy were associated with clinical resolution. Since MRSA is endemic in many long-term-care facilities, it is likely that MRSA-associated conjunctivitis will be increasingly recognized.

Adult↗

PubMed1989

Efficacy of oral ciprofloxacin plus rifampin for treatment of malignant external otitis.

Malignant external otitis is an invasive pseudomonal infection characteristically afflicting the elderly patient with diabetes mellitus. Therapy has traditionally consisted of the long-term administration of combination parenteral antibiotics, but morbidity and mortality remain substantial despite this therapy. We treated 11 consecutive patients with the oral combination of ciprofloxacin (750 mg twice daily) and rifampin (600 mg twice daily) for 6 to 12 weeks (mean, 8 weeks). Pseudomonas aeruginosa was isolated from ear canal or mastoid, and bone destruction was documented by computed tomography in all patients. Seven patients (64%) had ear irrigation before onset of the infection. Ten patients fulfilled the criteria of both clinical and bacteriologic cure. No serious adverse reaction to either antibiotic was observed. Otalgia and otorrhea responded at a mean of 6 and 4 days, respectively, following the initiation of therapy. The erythrocyte sedimentation rate fell from a mean pretherapy value of 81 mm/h (range, 41 to 138 mm/h) to 18 mm/h (range, 3 to 45 mm/h) after the completion of antibiotic therapy. Minimum inhibitory and bactericidal concentrations established that all organisms were sensitive to ciprofloxacin. Time-kill curve and checkerboard assays failed to demonstrate either synergy or antagonism between ciprofloxacin and rifampin. Serum inhibitory and bactericidal titers showed minimal increase in inhibition and killing of the bacteria with the addition of rifampin. Rifampin did not alter the pharmacokinetics of ciprofloxacin. The successful use of oral antibiotics for this difficult infection may be a major advance. Reduction in antibiotic costs and hospitalization and convenience of oral administration were of notable benefit.

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