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Biomedical subjects

R R Muder

Publications and source records attributed to R R Muder.

At least 73 records · Page 4Linked to original sources
PubMed1989

Antibiotic therapy for Pseudomonas aeruginosa bacteremia: outcome correlations in a prospective study of 200 patients.

PURPOSE AND PATIENTS AND METHODS: We performed a prospective clinical study of 200 consecutive patients with Pseudomonas aeruginosa bacteremias to analyze in vitro susceptibility and synergistic testing of antibiotics the patients received and clinical parameters to assess their relationship to survival. RESULTS: No significant correlation between in vitro susceptibility testing (minimal inhibitory concentrations/minimal bactericidal concentrations) and outcome could be demonstrated. Similarly, improved outcome could not be demonstrated for patients receiving antibiotic combinations that were synergistic in vitro (either time-kill or checker-board) versus those combinations that were not. There was also no correlation between results obtained by time-kill curve and checkerboard synergistic testing, i.e., combinations found to be synergistic by one method were not necessarily synergistic by the other method. Clinical parameters associated with improved survival were a urinary portal of entry and absence of neutropenia. Conversely, survival was significantly decreased when the portal was the respiratory tract. The mortality rate between patients receiving combination therapy (27%) and monotherapy (47%) was significant (p less than 0.02); this significant relationship held true for most subgroups including malignancy, nosocomial infection, and infection site. CONCLUSION: Increasing effort should be placed on ensuring timely administration of combination therapy to patients with P. aeruginosa bacteremia since the use of combination therapy was even more important in determining outcome than was underlying disease.

Adolescent↗
PubMed1989

Pseudomonas aeruginosa infections associated with use of povidone-iodine in patients receiving continuous ambulatory peritoneal dialysis.

Fifteen episodes of infection due to Pseudomonas aeruginosa, including peritonitis and catheter site infections, occurred in nine patients receiving continuous ambulatory peritoneal dialysis over a 27-month period. Eight episodes were associated with catheter loss. Occurrence of P aeruginosa infection was significantly associated with use of povidone-iodine solution to cleanse the catheter site. There was no association with use of povidone-iodine solution to disinfect tubing connections, use of other skin care products or exposure to other environmental sources of P aeruginosa. Cultures of available povidone-iodine products were negative. Local irritation and alteration in skin flora caused by antiseptic solution or low-level contamination of povidone-iodine solution are potential mechanisms of infection.

Catheters, Indwelling↗
PubMed1989

Community-acquired Legionnaires' disease.

Legionellae are ubiquitous aquatic organisms. They are unique among the agents commonly responsible for bacterial pneumonia in humans in that they are not part of the normal human flora but are acquired from environmental sources. Prospective studies have shown that legionellae consistently rank among the top three bacteria as etiologic agents of community-acquired pneumonia. The clinical presentation of Legionnaires' disease is not distinguishable from that of other bacterial pneumonias. Culture of respiratory secretions using selective media, combined with one or more rapid diagnostic methods (direct fluorescent antibody staining, radiolabelled DNA probe, or urinary antigen detection) provides a specific diagnosis in the vast majority of cases. Sporadic cases have been linked to legionella colonization of water systems in homes and the work setting. Antibiotics commonly used in the therapy of community-acquired pneumonias, such as beta-lactam agents, are ineffective. Specific therapy with erythromycin reduces mortality to less than 10%.

Anti-Bacterial Agents↗
PubMed1988

Staphylococcal carriage and infection in myasthenia gravis patients receiving therapeutic apheresis.

Populations exposed to repetitive needle puncture (such as hemodialysis patients, insulin-dependent diabetics, and parenteral drug abusers) are at increased risk for nasal carriage of Staphylococcus aureus. These groups appear to have increased susceptibility to serious staphylococcal infection as well. We performed a microbiologic survey on a group of patients receiving regular, long-term therapeutic apheresis for myasthenia gravis (MG), and compared the rate of nasal staphylococcal carriage with that found in control groups of MG patients not receiving apheresis and ambulatory general medical patients without known risk factors for staphylococcal carriage. Medical records were reviewed for episodes of significant staphylococcal infection occurring since commencement of apheresis. Nasal S. aureus carriage was found in 9/29 (31%) apheresis patients, 8/30 (27%) MG controls, and 8/30 (27%) general medical controls. No significant difference in frequency of apheresis was noted between carriers and noncarriers. A single episode of S. aureus bacteremia occurred in 95 patient-years of apheresis therapy. We conclude that therapeutic apheresis for MG does not increase the risk of staphylococcal carriage, and that serious infection is infrequent.

Adolescent↗
PubMed1988

Occult endemic tuberculosis in a chronic care facility.

During the course of a tuberculosis skin testing program at a chronic care Veterans Administration Medical Center, we uncovered evidence of occult transmission of endemic tuberculosis. Skin test conversion of eight patients (one of whom had unsuspected progressive primary tuberculosis) and two employees was ultimately traced to a patient in whom tuberculosis was first diagnosed at autopsy three years earlier. Identification of employee skin test conversions was a key factor in recognizing and terminating disease transmission. Throughout the institution, 33% of patients were tuberculin-positive; 10.8% demonstrated the booster phenomenon after initial negative skin tests. Prevalence of tuberculin positivity among employees was 28%. Twelve percent of initially tuberculin-negative employees converted during employment. Our experience documents the value of tuberculin testing of both patients and staff in a chronic care environment, and the necessity of vigorous investigation of skin test conversions.

Adult↗
PubMed1987

The radiologic manifestations of Legionella pneumonia.

A number of radiologic features on chest X-ray may aid in diagnosis and management of the patient with legionella infection. The infiltrates in legionnaires' disease frequently progress despite initiation of appropriate antibiotic therapy. Pleural effusion is common and occasionally seen even in the absence of lung field infiltrates. Pleural-based infiltrates associated with pleuritic pain may mimic pulmonary embolism. Circumscribed peripheral densities are commonly seen in immunosuppressed patients. Cavitation is also a prominent feature in this patient group and may develop during clinical improvement. Radiographic severity does not correlate with clinical outcome. Resolution of infiltrates may be slow, and the tendency for delayed clearing should be considered before initiating further invasive diagnostic investigation. Infections due to Tatlockia (Legionella) micdadei and Legionella bozemanii are more commonly reported in immunocompromised hosts; the radiographic manifestations are similar to those seen in Legionella pneumophila infection in the immunosuppressed.

Adult↗
PubMed1987

Infections caused by Pseudomonas maltophilia. Expanding clinical spectrum.

Pseudomonas maltophilia (Xanthomonas maltophilia) is a frequently isolated commensal that is gaining increasing recognition as an opportunistic pathogen in debilitated hosts. We report three unusual infections due to P maltophilia that illustrate the ability of the organism to cause life-threatening illness. We describe a case of postoperative meningitis, a case of recurrent bacteremia complicated by ecthyma gangrenosum, and a case of native valve endocarditis in a drug addict. Because of frequent isolation from noninfected sites, the pathogenic potential of P maltophilia may be overlooked. The notable resistance of this organism is commonly used beta-lactam and aminoglycoside antibiotics may complicate therapy.

Aged↗
PubMed1986

Significance of isolation of Aspergillus from the respiratory tract in diagnosis of invasive pulmonary aspergillosis. Results from a three-year prospective study.

The isolation of Aspergillus species from respiratory secretions has been regarded as being of limited usefulness in the antemortem diagnosis of invasive pulmonary aspergillosis. One hundred and eight consecutive patients were evaluated in whom Aspergillus species were isolated from respiratory secretions. Invasive aspergillosis was not demonstrated in non-immunosuppressed patients or in patients with solid tumors in the absence of neutropenia. Lung tissue was examined in 17 patients with leukemia and/or neutropenia; all had invasive aspergillosis. Tissue examination was not performed in 20 neutropenic patients; of 17 not receiving antifungal therapy, 16 died. Multivariate statistical analysis showed that neutropenia and absence of cigarette smoking were significant predictors of invasive aspergillosis in patients with respiratory tract cultures yielding Aspergillus. All cases of invasive aspergillosis were associated with A. fumigatus or A. flavus. The isolation of A. fumigatus or A. flavus from the respiratory tract of a patient with leukemia and/or neutropenia is highly predictive of invasive infection. Empiric amphotericin B therapy, without the necessity for tissue diagnosis, should be considered in this patient subgroup.

Adolescent↗
PubMed1985

Tatlockia micdadei (Pittsburgh pneumonia agent) growth kinetics may explain its infrequent isolation from water and the low prevalence of Pittsburgh pneumonia.

Sediment and indigenous microflora taken from water distribution systems has been shown to promote the survival of Legionella pneumophila. The effect of sediment and indigenous microflora on Tatlockia micdadei (Pittsburgh pneumonia agent, PPA) was evaluated by growth curve experiments. Symbiosis between PPA and environmental bacteria was demonstrated by satellitism experiments. Unlike L. pneumophila, the concentration of PPA remained stationary in test tube suspensions containing both microflora and sediment. The difference in the ecology between the two organisms may explain the infrequent environmental recovery of PPA and, ultimately, the epidemiologic differences between Legionnaires disease and Pittsburgh pneumonia.

Bacteria↗
PubMed1985

Isolation of Legionella pneumophila from blood with the BACTEC system: a prospective study yielding positive results.

In a prospective study of 16 patients with Legionnaires disease confirmed by cultural isolation of Legionella pneumophila from the respiratory tract, 38% (6 of 16) had positive blood cultures. Daily subcultures were made onto buffered charcoal-yeast extract plates from 6B aerobic and 7C anaerobic BACTEC blood culture bottles (Johnston Laboratories, Inc., Towson, Md.). Isolation of L. pneumophila was achieved from both aerobic and anaerobic bottles. L. pneumophila growth indices failed to exceed the BACTEC threshold limits; thus, the organism would have been overlooked despite its presence in the blood culture bottles. Bacteremic patients had statistically significant higher quantities of L. pneumophila isolated from sputum and visualized on direct fluorescent antibody stains. Thus, the potential exists for improved diagnosis of Legionella infection by a relatively noninvasive procedure (blood culture) with an instrument already in use in many hospital laboratories.

Aerobiosis↗
PubMed1984

Efficacy of two third-generation cephalosporins in prophylaxis for head and neck surgery.

Optimal antimicrobial prophylaxis during head and neck surgery is as yet unclear. The semisynthetic third-generation cephalosporin antibiotics would appear to have potential usefulness because of their broad antibacterial spectrum, favorable pharmacokinetic properties, and record of safety. Eighty patients were prospectively randomized into this placebo-controlled, double-blind study to receive either placebo, cefoperazone sodium, or cefotaxime sodium preoperatively and for 24 hours postoperatively. Infection rates were 78% for the placebo group and 10% for the group receiving the cephalosporin antibiotics. Infections were polymicrobial. Anaerobic bacteria constituted 42% of the pathogens isolated. Wound and serum antibiotic concentrations exceeded the minimal inhibitory concentration of the bacterial flora. This study establishes the necessity of antimicrobial prophylaxis for contaminated oncologic procedures of the head and neck. Our experience indicates that cefoperazone and cefotaxime are particularly useful.

Bacteria↗
PubMed1984

Penetration of cefoperazone into surgical wound drainage in patients undergoing head and neck surgery.

Cefoperazone penetration into skeletal muscle and wound drainage in patients undergoing major surgery of the head and neck was measured by high-pressure liquid chromatography. Cefoperazone (2 g) was infused over 30 min before surgery and every 8 h for three postoperative doses. Simultaneous samples of serum and sternomastoid muscle were collected in 18 patients at 135 to 480 min after infusion. Mean cefoperazone concentrations in muscle tissue were 17.1% of those in simultaneously collected serum. Steady-state wound drainage concentrations after the fourth dose of cefoperazone averaged 55.2 micrograms/ml at 1 to 2 h and 62.1 micrograms/ml at 2 to 3 h. Simultaneous steady-state serum and wound fluid samples were obtained at regular intervals in six patients. In all patients, the peak level in wound fluid exceeded 25 micrograms/ml. Thus, cefoperazone reaches interstitial fluid concentration in soft tissue that exceeds the MICs required to inhibit the usual pathogens found at the site of wound infection after head and neck surgery.

Cefoperazone↗
PubMed1984

Pneumonia caused by Pittsburgh pneumonia agent: radiologic manifestations.

Using an objective scoring system, chest radiographs were reviewed in 23 cases of pneumonia due to the Pittsburgh pneumonia agent (PPA, Tatlockia micdadei, Legionella micdadei), including six cases of pneumonia with simultaneous isolation of PPA and L pneumophila (Legionnaires' disease). Infiltrates were typically segmental to lobar; nodular infiltrates were noted in three cases. Spread to additional lobes after presentation occurred in four of 17 PPA infections. Pneumonia caused by both PPA and L pneumophila was unusually severe, with involvement of all lobes occurring in four of six cases, compared with one of 17 cases of PPA infection (p less than 0.02). Radiographic severity did not correlate with underlying disease, immune status, or outcome. The majority of patients receiving erythromycin demonstrated objective radiologic improvement. In a patient population that included nonimmunosuppressed patients, nodule formation and rapid radiologic progression were not found to be characteristic of PPA pneumonia.

Aged↗
PubMed1984

Addition of rifampin to ticarcillin-tobramycin combination for the treatment of Pseudomonas aeruginosa infections: assessment in a neutropenic mouse model.

The efficacy of ticarcillin (100 mg/kg), tobramycin (1 mg/kg), and rifampin (43 and 7.2 mg/kg) individually and in combination was assessed in neutropenic mice infected with an LD90 of one of four Pseudomonas aeruginosa isolates. The study end point was survival at 120 hours after infection. Treatment with the triple combination, ticarcillin plus tobramycin plus rifampin (43 mg/kg), was significantly superior to the double combination of ticarcillin plus tobramycin (p less than 0.01). Although treatment with rifampin (43 mg/kg) alone yielded results similar to treatment with the triple combination in mice infected with three of the four isolates, rifampin-resistant mutants (minimal inhibitory concentration greater than 1000 micrograms/ml) of P. aeruginosa were frequently isolated from surviving mice (26% of mice sampled). In contrast, in mice treated with the triple combination, rarely were rifampin-resistant mutants isolated (3% of mice sampled). Rifampin alone was active against P. aeruginosa isolates only when peak serum concentrations of rifampin exceeded the rifampin minimal bactericidal concentration of the infecting isolate. The addition of rifampin to a "standard" therapy of antipseudomonal penicillin plus aminoglycoside may be useful in the treatment of serious P. aeruginosa infection.

Animals↗
PubMed1983

Legionellaceae in the hospital water-supply. Epidemiological link with disease and evaluation of a method for control of nosocomial legionnaires' disease and Pittsburgh pneumonia.

An epidemiological link was found between contamination of a hospital water-supply by Legionella pneumophila and by Pittsburgh pneumonia agent (PPA) and subsequent cases of nosocomial legionnaires' disease and Pittsburgh pneumonia. The extent of L pneumophila isolation from the water-supply paralleled the occurrence of disease. Whenever L pneumophila was isolated from more than 30% of ten selected water sites, nosocomial legionellosis occurred. The temperature of the hot water tanks was raised to 60-77 degrees C for 72 h, and water outlets were flushed for 30 min with hot water. A decline in numbers of L pneumophila and PPA in the water-supply was followed by a fall in the incidence of legionnaires' disease and Pittsburgh pneumonia. In addition, intermittent raising of the temperature in the hot water system decreased both the number of months in which disease occurred and the proportion of nosocomial pneumonias caused by these organisms.

Cross Infection↗
PubMed1983

Nosocomial Legionnaires' disease uncovered in a prospective pneumonia study.

Most hospitals have yet to record a case of nosocomial legionnaires' disease; the importance of isolation of Legionella pneumophila in the water system of such an institution is unclear. We undertook a prospective pneumonia study in tandem at a veterans hospital where legionnaires' disease was known to be endemic and a community teaching hospital where legionnaires' disease had never been documented. Legionella serological tests were performed on all patients with pneumonia; selective culture media and direct fluorescent antibody testing for Legionella were made readily available. Simultaneous environmental surveys for Legionella were performed. At the community hospital, we discovered that 64% of sites in the water distribution system yielded L pneumophila and that 14.3% of nosocomial pneumonias were legionnaires' disease. The epidemiologic implications of these findings are discussed. Options concerning case detection and eradication measures in the face of hospital water contamination with L pneumophila are presented.

Adult↗
PubMed1983

Myelopathy after herpes zoster.

A 73-year-old woman with a remote history of carcinoma of the ovary had herpes zoster involving several lumbosacral dermatomes. There subsequently developed a progressive myelopathy with normal myelographic findings and CSF pleocytosis. Vidarabine (15 mg/kg/day) was given for ten days. No further progression occurred. The syndrome of progressive myelopathy following herpes zoster is rare; direct viral invasion of the cord with subsequent necrosis appears to be the pathogenic mechanism. Antiviral therapy may have halted progression, but it did not lead to recovery of function.

Aged↗