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Biomedical subjects

W R McCabe

Publications and source records attributed to W R McCabe.

At least 37 records · Page 2Linked to original sources
PubMed1985

A randomized study comparing a transparent polyurethane dressing to a dry gauze dressing for peripheral intravenous catheter sites.

We studied rates of peripheral intravenous (IV) catheter tip and insertion site colonization after randomly assigning patients to transparent polyurethane (TP) dressings (N = 316) or dry gauze (DG) dressings (N = 421). The study was conducted during both summer and fall seasons, in a facility which lacked air conditioning. All patients had a teflon plastic catheter inserted, maintained and cultured by a member of the IV therapy team; no antibiotic or antiseptic ointments were used. Colonization rates were higher in the summer than in the fall for both catheter tips (9.0% vs 3.5%, p = 0.005) and sites (21.6% vs 7.0%, p = 0.001). During the summer season, the rate of catheter tip colonization with TP dressings was nearly twice that of DG dressings (12.4% vs 6.8%, p = 0.04). Logistic regression analysis indicated that catheter tip colonization was associated with the summer season (odds ratio = 3.0, 95% CI 1.4-6.2) and TP dressings (odds ratio = 1.8, 95% CI 1.1-3.2), and that site colonization was associated with both summer (odds ratio = 4.0, 95% CI 2.2-7.1) and receipt of antibiotics (odds ratio = 1.9, 95% CI 1.1-3.2). Coagulase-negative staphylococci were isolated from 55.5% of the colonized catheter tips and insertion sites. The data suggest that bacterial colonization of peripheral IV catheters is increased in summer, and that use of TP dressings may increase both tip colonization and cost nearly twofold.

Bacterial Infections↗
PubMed1984

Mycobacterial cervical lymphadenopathy. Relation of etiologic agents to age.

Age-related differences in etiology were examined in 214 instances of mycobacterial cervical lymphadenopathy. In adults, Mycobacterium tuberculosis was isolated from 147 lymph nodes and "atypical" mycobacteria was isolated from seven nodes. In contrast, M tuberculosis was isolated from only five nodes from children while other mycobacteria were isolated from 55 nodes. Mycobacterium tuberculosis clearly preponderates as the cause of mycobacterial cervical adenitis in adults while other mycobacteria are the cause of most cervical adenitis in children. The preponderance of Mycobacterium avium-intracellulare in cervical adenitis in children contrasts with reports of Mycobacterium scrofulaceum as the most frequent causative agent in other geographic areas and may reflect either a change in causative agents or geographic differences. However, the finding of M tuberculosis in 8% of nodes indicates that other mycobacteria cannot be assumed to be the only cause of this disease in children.

Adult↗
PubMed1984

Contaminated medication nebulizers in mechanical ventilator circuits. Source of bacterial aerosols.

The contamination rates of medication nebulizers inserted into mechanical ventilator circuits were studied. Semiquantitative techniques were used to sample the reservoir fluid from in-line nebulizers during the first 24 hours after a circuit change. In the initial survey, high levels of contamination (organism concentrations above 10(3)/ml) were present in 13 (68 percent) of the 19 nebulizer reservoirs, and bacterial aerosols were produced by 10 (71 percent) of 14 nebulizers. Gram-negative bacilli were the predominant organisms isolated. Nebulizer contamination originated primarily from reflux of contaminated condensate in the ventilator circuit. When nebulizers were cleaned after each treatment, a reduced rate of contamination was found. Small bacterial aerosols (less than 3 microns in size) were produced in vitro after inoculation of nebulizers with gram-negative bacilli in concentrations isolated from in-use nebulizers. Contaminated in-line medication nebulizers generate small-particle bacterial aerosols that may increase the risk of ventilator-associated pneumonia and therefore should be cleaned or disinfected after each treatment rather than every 24 hours.

Aerosols↗
PubMed1984

Xanthogranulomatous pyelonephritis caused by methicillin-resistant Staphylococcus aureus.

Localized xanthogranulomatous pyelonephritis due to methicillin-resistant Staphylococcus aureus developed in a 41-year-old diabetic patient. She had recurrent bacteremia despite appropriate therapy with vancomycin. Nephrectomy was required for cure and clinical diagnosis. This report emphasizes differences in the clinical presentation and pathogenesis of xanthogranulomatous pyelonephritis caused by S. aureus. Compared with the common form of xanthogranulomatous pyelonephritis caused by gram-negative bacilli, the localized disease due to S. aureus probably results from hematogenous seeding and is not associated with nephrolithiasis or ureteral obstruction. Furthermore, this report indicates that xanthogranulomatous pyelonephritis may be caused by methicillin-resistant S. aureus, a rapidly emerging nosocomial pathogen.

Adult↗
PubMed1984

Pseudobacteremia traced to cross-contamination by an automated blood culture analyzer.

Twenty-three episodes of pseudobacteremia occurring over a seven-month period were traced to cross-contamination by the automated blood culture analyzer (BACTEC 460) used in the microbiology laboratory. An epidemiologic investigation of an unusual cluster of three patients with pseudobacteremia caused by oxacillin-resistant Staphylococcus aureus led to the identification of the problem. Mock trials of the blood culture procedure confirmed that the blood culture analyzer was the source of contamination. After the needle sterilizer was replaced by the manufacturer, the problem of cross-contamination abated. Contamination of sterile blood cultures by an instrument intended to identify bacteremia rapidly may lead to incorrect diagnosis, unnecessary administration of antibiotics and prolonged hospitalization. Because of the widespread use of automated blood culture analyzers in the US, physicians, microbiologists, and infection control personnel should be alert to the possibility of cross-contamination and the subtle way in which it may present.

Blood↗
PubMed1984

A clinical study of moxalactam in the treatment of infections due to gram-negative bacilli.

47 episodes of infection due to gram-negative bacilli in 44 patients were treated with moxalactam in an open clinical trial of efficacy and safety. These included 25 urinary tract infections, 8 cases of pneumonia, 2 cases of meningitis, 3 wound and skin infections and 1 case each of peritonitis and osteomyelitis. 17 episodes of gram-negative bacteremia, either associated with local infection or primary septicemia, were treated. Cure, as defined as satisfactory clinical response with eradication of the infecting organism and absence of relapse, occurred in 34/47 episodes (72%). Fatality was associated with 5/17 episodes of bacteremia, but rapid clearance of bacteremia occurred in all but one of the 12 survivors. The most significant complication of therapy was colonization and superinfection with moxalactam-resistant organisms. Fatal infection with moxalactam-resistant Serratia marcescens and Pseudomonas aeruginosa occurred in one case of pneumonia caused by S. marcescens initially sensitive to moxalactam. Significant adverse effects were primarily hematologic with prolongation of clotting times in 4 patients (associated with bleeding in 2), eosinophilia in 6 patients, and thrombocytosis in 4.

Adult↗
PubMed1984

Extrapulmonary tuberculosis revisited: a review of experience at Boston City and other hospitals.

During a 10-year period, 136 patients with extrapulmonary tuberculosis were seen at Boston City Hospital and other hospitals affiliated with Boston University School of Medicine. Review of these cases revealed that the prevalence of extrapulmonary tuberculosis was declining less rapidly than that of pulmonary disease. Extrapulmonary disease represented 4.5% of all new cases of active tuberculosis and tended to occur in older patients than in previous reports. Sites of involvement included lymph nodes, blood, genitourinary tract, bone and articular sites, the meninges, peritoneum, adrenal glands, pericardium, and miscellaneous sites, in this order. Diagnosis was confirmed by a variety of techniques whose relative merits are discussed. Overall, 14 deaths occurred among the 136 patients. One-half of the deaths resulted from causes other than tuberculosis and two patients died before diagnosis and initiation of therapy. Evaluation of the relative efficacy of therapeutic regimens was hampered by a high degree of recidivism in this population and the multitude of regimens utilized. These observations indicate that extrapulmonary tuberculosis still occurs with substantial frequency among patients seen in "inner-city" hospitals and that its recognition may be complicated by its occurrence in older patients with other medical conditions.

Adolescent↗
PubMed1983

Pathophysiology of bacteremia.

Despite the frequency and importance of both nosocomial and "community-acquired" bacteremia, definitive information concerning crucial pathophysiologic events in human bacteremia remains sparse. An extensive variety of clinical manifestations, such as fever, rigors, shock, altered circulatory dynamics, cutaneous manifestations changes in the coagulation, complement, and other mediator systems, and effects on the lungs, heart, kidney, liver, and other end organs, have been described, but it is difficult to determine the relative frequency of these events in bacteremia caused by different species. The extensive number of bacterial species capable of producing bacteremia and variations in the type of presentation, such as acute, asymptomatic, and chronic, even when bacteremia is produced by the same species, undoubtedly contribute to this difficulty and suggest that a variety of pathophysiologic mechanisms occur in various bacteremias. In contrast, the relative frequency of various manifestations and some pathophysiologic mechanisms have been better delineated in Gram-negative bacteremia. The development of bacteremia enhances the lethality of most types of localized infection and several studies have demonstrated a relation between the magnitude of bacteremia and the outcome of the disease. Among various pathophysiologic alterations, mechanisms involved in the production of fever have been delineated most clearly. Fever appears to reflect a "common pathway" with almost all infectious agents and results from release of endogenous pyrogen from phagocytic cells. Endogenous pyrogen regulates the thermostatic setting of the body through its effect on the anterior hypothalamus. Endogenous pyrogen seems identical with Interleukin 1 and exerts a variety of other biologic activities. An extensive number of bacterial components have been proposed as "effectors" and an equally large number of endogenous substances proposed as "mediators" of the pathophysiologic events in bacteremia. The importance of many of these effectors and mediators has been postulated largely on the basis of in vitro and animal studies. The lack of critical clinical studies hampers extrapolation of these experimental studies to human bacteremia. The development of more effective therapy for the complications of bacteremia, such as shock, will continue to be hampered until the mechanisms involved in the production of those pathophysiologic events that are crucial determinants of outcome have been delineated more precisely in human disease.

Bacterial Toxins↗
PubMed1983

Bacteremia due to Fusobacterium species.

Twenty-six patients were identified as having bacteremia with Fusobacterium species over a five-year period at Boston City Hospital. They represented 0.9 percent of bacteremic patients and were equally divided as to sex. Bacteremia with Fusobacterium occurred primarily in young adults and in patients over 60 years of age and was not observed in children. In 16 patients (62 percent), Fusobacterium was the only blood culture isolate. The most common primary foci of infection were the female genital tract, the upper respiratory tract, the oral cavity, and the lower respiratory tract. Five patients had primary foci of infection that were initially occult. Three of these patients were found to have unappreciated oral and pharyngeal lesions, and one had a liver abscess; no primary infection was established in the remaining patient. Shock related to bacteremia developed in six patients (23 percent), four of whom had Fusobacterium species as the only blood culture isolate. Death occurred in three patients (12 percent), all of whom were over 60 years old. Metastatic infection occurred in only one patient in whom hematogenous osteomyelitis developed. Postpartum fusobacterial bacteremia was uniformly benign. Evaluation of bacteremia with Fusobacterium species in nonpostpartum patients, without an overt focus of infection, should be directed to a search for occult abscess, especially of the upper respiratory tract and oral cavity.

Adolescent↗
PubMed1983

Vancomycin treatment of bacteremia caused by oxacillin-resistant Staphylococcus aureus: comparison with beta-lactam antibiotic treatment of bacteremia caused by oxacillin-sensitive Staphylococcus aureus.

The epidemiology and therapy of 29 episodes of bacteremia caused by oxacillin- and aminoglycoside-resistant Staphylococcus aureus (OARSA) were compared with 29 episodes of bacteremia due to oxacillin-sensitive S. aureus (OSSA) that occurred during a 36-month period. Patients with bacteremia due to OSSA were younger (P less than 0.05) and were admitted more frequently with acute traumatic injury (P less than 0.01). The overall survival rate one month after persistent bacteremia was 74% for patients with OARSA bacteremia treated with vancomycin compared with 70% for patients with OSSA bacteremia treated with a beta-lactam antibiotic. The results indicate that vancomycin is an effective antibiotic for the treatment of bacteremia caused by OARSA and suggest that its effectiveness is comparable to that of beta-lactam antibiotic treatment of bacteremia due to OSSA.

Anti-Bacterial Agents↗
PubMed1983

Immunization with rough mutants of Salmonella minnesota. IV. Protection by antisera to O and rough antigens against endotoxin.

The protection by antisera to O antigens and antigens (lipid A, the Re 595 mutant of Salmonella minnesota, and the J5 mutant of Escherichia coli) of the core portion of endotoxin against lethal challenge with lipopolysaccharide (LPS) was compared. Rabbits immunized with the Re mutant developed antibody that protected mice against challenge with S. minnesota or Salmonella typhosa LPS. Antisera to heterologous O antigen and lipid A were not protective, whereas homologous antisera and antiserum to the Re or J5 mutant protected against lethal challenge. On a volumetric basis, O-specific antiserum was consistently somewhat more protective than antiserum to the Re mutant, which was slightly more protective than antiserum to the J5 mutant. When comparisons were made using passive transfer to similar quantities of hemagglutinating or precipitating antibody, antiserum to the Re mutant was considerably more protective than O-specific antiserum. This greater protection is hypothesized to result from more effective masking of the toxic lipid A moiety by antibody to the rough mutants than by O-specific antibody.

Animals↗
PubMed1982

Contamination of mechanical ventilators with tubing changes every 24 or 48 hours.

We studied the contamination of ventilator circuits in order to assess the need for daily changes of tubing. Patients requiring continuous mechanical ventilation were randomly selected for tubing changes at 24 hours (Group 1) or at 48 hours (Group 2). Samples of inspiratory-phase gas from ventilators with standardized settings were cultured according to the tube-broth method of Edmondson and Sanford. The frequency of positive cultures from 128 ventilators in Group 1 (30 per cent) was not significantly different from that for 112 ventilators in Group 2 (32 per cent). Gram-negative bacteria were most frequently isolated from patient's sputum and ventilator inspiratory-phase gas, but no species predominated in either group of patients. Further studies performed with the Aerotest and Andersen air samplers confirmed that the levels of inspiratory-phase-gas contamination were low in both groups. In addition, quantitative analysis of colonization of the tubing demonstrated no significant increase in colonization between 24 and 48 hours. The absence of a significant difference in inspiratory-phase-gas contamination or tubing colonization suggests that ventilator tubing need be changed only every 48 hours.

Bacteria↗
PubMed1981

Meningitis caused by Acinetobacter calcoaceticus var anitratus. A specific hazard in neurosurgical patients.

Acinetobacter calcoaceticus var anitratus caused meningitis in five patients between 1968 and 1978 at two hospitals affiliated with Boston University School of Medicine. All patients had had head trauma or neurosurgical procedures prior to the development of meningitis. The course of the disease was relatively indolent in that fulminant disease did not occur even when initial therapy was inappropriate and bacteria persisted in CSF. All five patients survived. On Gram's stain of CSF, A calcoaceticus may be confused with meningococci, pneumococci, or Haemophilus influenzae and thus cause delay in appropriate diagnosis and therapy.

Acinetobacter Infections↗
PubMed1981

A large outbreak of infections caused by a strain of Staphylococcus aureus resistant of oxacillin and aminoglycosides.

An extensive outbreak of nosocomial infections caused by oxacillin- and aminoglycoside-resistant Staphylococcus aureus (OARSA) occurred over a 16 month period. A total of 349 isolates of OARSA were obtained from 174 patients. Colonization with OARSA was found in 92 patients. There was 120 infections in 82 patients; 50 were surgical wound infections, 13 were nonsurgical wound infections, six were pneumonias, 15 were urinary tract infections, 12 were intravenous site infections, and there were 19 episodes of bacteremia (seven transient, 12 persistent). In patients with persistent bacteremia, the mortality rate was 33 percent. In patients treated for persistent bacteremia with vancomycin, the survival rate was 80 percent. Infections were highly associated with the surgical intensive care unit, and 90 percent of the isolates of OARSA tested had the same phage-type. Elderly patients with significant underlying disease, a history of previous surgery or of prior antimicrobial therapy appeared to be at increased risk for OARSA infections. OARSA were resistant to multiple antibiotics besides oxacillin, but all isolates were sensitive to vancomycin and rifampin. Three surgical intensive care unit nurses were found to be nasal carriers of OARSA, and one nurse had dermatitis of both hands colonized with OARSA. Following the removal of these nurses from the surgical intensive care unit and the institution of strict infection control measures, the number of OARSA infections and colonizations decreased to less than one per month. OARSA produces serious nosocomial disease, and epidemiologic intervention was effective in controlling this outbreak.

Adult↗
PubMed1980

An outbreak of type 1 pneumococcal pneumonia in a men's shelter.

A striking increase in blood culture isolates of Streptococcus pneumonia capsular type 1 was noted at Boston City Hospital in early 1978. The increased incidence of type 1 pneumococcal bacteremia was due, at least in part, to an outbreak of disease among alcoholic, male clients of Boston's largest shelter. Residents of the shelter also were found to have a high rate of nose and throat carriage of type 1 pneumococci. This outbreak of bacteremic pneumococcal pneumonia is compared with endemic disease caused by other serotypes observed at Boston City Hospital during the same period and with previous studies of epidemic pneumococcal disease. Routine serotyping of pneumococcal isolates is important, especially in light of the emergence of pneumococci resistant to multiple antibiotics and of the renewed use of polysaccharide vaccines.

Alcoholism↗
PubMed1980

In vitro studies of moxalactam (LY127935), a new beta-lactam antibiotic with significant activity against gram-negative bacteria.

Moxalactam (LY127935) is a new beta-lactam antibiotic which is chemically related to the cephalosporins. The agent is highly active against the Enterobacteriaceae, with most organisms sensitive to 0.1 mcg/ml or less. It is also active at low concentration against gentamicin-resistant strains of Providencia and Serratia. Minimal inhibitory concentrations of moxalactam for Pseudomonas aeruginosa are approximately four-fold lower than those of carbenicillin for the same isolates. It is highly active against Hemophilus influenzae, including ampicillin-resistant strains, with all strains tested sensitive to 0.1 mcg/ml or less. The majority of strains of Neisseria gonorrheae and Neisseria meningitidis are sensitive to 0.1 mcg/ml or less. Moxalactam is more active against Bacteroides fragilis than cefoxitin. However, activity of moxalactam against gram-positive cocci was uniformly less than cephalothin and other cephalosporins tested. Little effect of inoculum size was observed with moxalactam except for particular strains of gram-negative bacilli. The drug was found to be 40-43% bound to human serum proteins.

Amikacin↗