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Biomedical subjects

L M Baddour

Publications and source records attributed to L M Baddour.

86 records · Page 5Linked to original sources
PubMed1984

Disseminated histoplasmosis associated with the acquired immune deficiency syndrome.

Disseminated histoplasmosis developed in a previously healthy man as the initial manifestation of the acquired immune deficiency syndrome. Following apparently successful therapy with intravenous amphotericin B, he presented two months later with a subacute pneumonitis syndrome diagnosed by bronchoscopy as Pneumocystis carinii pneumonia. He showed response to intravenous trimethoprim/sulfamethoxazole with resolution of his symptoms and clearing of chest radiographic findings. While he was receiving antibiotics, oral candidiasis developed and has persisted for more than two months despite topical therapy and discontinuation of all antibiotics.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Production of experimental endocarditis by coagulase-negative staphylococci: variability in species virulence.

The abilities of 11 coagulase-negative staphylococcal isolates of human origin to establish infective endocarditis in a rat model were compared. Seven of the strains were Staphylococcus epidermidis, the species most commonly causing endocarditis in humans. The other four strains were Staphylococcus hominis, an infrequent cause of endocarditis. Four of the seven strains of S. epidermidis and two of the four strains of S. hominis elaborated surface slime. With an inoculum of 10(7) colony-forming units, endocarditis was established in all of 77 rats injected with S. epidermidis but in only five (12.5%) of 40 animals injected with S. hominis (P less than .001). Strains of S. epidermidis were significantly more resistant to phagocytic killing in vitro than were strains of S. hominis. These data indicate that there are major differences in the virulence of various species of coagulase-negative staphylococci, both in vivo and in vitro, and that these differences are reflected in the observed incidence of disease caused in humans by the respective species.

Animals↗
PubMed1982

Recurrent cellulitis after saphenous venectomy for coronary bypass surgery.

We describe a previously unreported complication of coronary artery bypass grafting, recurrent cellulitis. Five patients had 20 episodes of acute cellulitis, each occurring in the lower extremity in which saphenous venectomy had been done. The cases were striking because the patients presented with high fever and considerable systemic toxicity. The appearance of the lesions, presence in one case of obvious associated lymphangitis, and prompt response in three instances to therapy with penicillin alone all suggest group A streptococcal infection. In one case, a beta-hemolytic, bacitracin-susceptible Streptococcus strain was isolated from the lesion. The pathogenesis of this syndrome remains obscure but, based on our understanding of postsurgical erysipelas, this cellulitis likely results from the interplay of several factors, including local compromise of lymphatic drainage, direct bacterial invasion, and acquired hypersensitivity to streptococcal exotoxins.

Adult↗
PubMedDate not supplied

Antimicrobial prophylaxis of experimental endocarditis caused by Staphylococcus epidermidis.

Using two different strains of Staphylococcus epidermidis in a rat model of experimental endocarditis, we examined the prophylactic efficacy of cefamandole (200 mg/kg/dose), cefazolin (200 mg/kg/dose), nafcillin (200 mg/kg/dose), and vancomycin (20 mg/kg/dose). In vitro susceptibility testing demonstrated that both test strains were resistant to methicillin and cefazolin and susceptible to cefamandole and vancomycin. A 10(6) cfu inoculum was used for both strains, an inoculum which produced endocardial infections in greater than 90% of rats. Initial doses of each antibiotic were given 45 min to 1 h prior to bacterial challenge and were followed by six additional doses of each antibiotic administered subcutaneously every 6 h. The efficacy rates of cefamandole (84.0%) and cefazolin (70.8%) were exactly the same for rats infected with either S. epidermidis strain. Similar efficacy rates were seen in rats infected with either strain and treated with vancomycin (94.4% and 86.7%). Unlike the other three drugs, the efficacy of nafcillin was quite different in rats challenged with the two strains (62.5% and 38.5%, p = 0.19). It appears that cefamandole and cefazolin may have considerable prophylactic efficacy against certain infecting strains of methicillin-resistant, coagulase-negative staphylococci when relatively large doses of cephalosporins are administered subcutaneously in this animal model.

Animals↗
PubMedDate not supplied

Staphylococcus aureus and other bacteremias in hemodialysis patients: antibiotic therapy and surgical removal of access site.

BACKGROUND: Bacteremia is commonplace in patients undergoing hemodialysis since the vascular access site is a ready source of infection. Mortality is notably high. However, uncertainties exist with respect to therapy including indications for surgical removal of vascular access site and duration of therapy. We therefore conducted a large-scale collaborative study of bacteremia in hemodialysis patients in six US academic medical centers to define the epidemiology of such infections and to address issues of management. PATIENTS AND METHODS: We conducted a prospective observational study over 2 years. Severity of illness at onset of bacteremia was defined by objective criteria. Patients were followed for 90 days to assess late complications including endocarditis and mortality. Univariate and multivariate analyses were used to assess risk factors for mortality. RESULTS: Patients experiencing 127 consecutive episodes of bacteremia were enrolled. The most common cause of bacteremia was Staphylococcus aureus (31%), followed by aerobic gram-negative bacilli (28%) and coagulase-negative staphylococci (13%). Polymicrobial bacteremia occurred in 6% of patients. The most frequent focus of infection was the access site for hemodialysis, although urinary tract, gastrointestinal tract and lung were also implicated. Aerobic gram-negative bacilli and enterococci usually originated from the urinary tract. S. aureus was significantly more likely to cause infection of the access site than other bacteria (p = 0.0001). S. aureus endocarditis was diagnosed in two patients who were receiving antibiotic therapy for S. aureus bacteremia. Removal of the infected access site (shunt, fistula, catheter) was performed for 86% of the patients (95% of the intravenous catheters and 80% of the arteriovenous fistulas/shunts). Overall mortality was 33% at 90 days and was significantly associated with severity of illness at onset of antibiotic therapy and age >60 years. Mortality was not significantly different in patients undergoing surgical removal of infected access site versus those treated with antibiotics alone. CONCLUSION: When S. aureus was isolated from the blood, the access site was the most frequent source. Surgical removal of the access site did not have a notable impact on mortality. Until a randomized trial proves otherwise, it appears that surgical removal of the access site can be individualized. Selected patients who are less severely ill (based on objective criteria) can maintain their hemodialysis access site and be treated with 2 weeks of antibiotic therapy.

Abscess↗
PubMedDate not supplied

Twelve-year review of recurrent native-valve infective endocarditis: a disease of the modern antibiotic era.

Recurrent cases of native-valve endocarditis have been seen for only the past four decades. In a review of the English-language literature over the past 12 years, 281 cases of recurrent infective endocarditis were found. Males were more than three times more commonly identified than females. Intravenous drug use was a designated risk factor for endocarditis in 43% of patients. Compared with patients with other risk factors for endocarditis, patients with intravenous drug use were significantly more likely (P less than .005) to suffer a recurrent bout of native-valve endocarditis within 12 months after the primary (or previous) episode. A greater variety of organisms were isolated from patients with recurrent endocarditis than from those with primary endocarditis. Valvular involvement was evenly distributed among the aortic, mitral, and tricuspid valves for both primary and recurrent episodes of infection. While complications of recurrent native-valve endocarditis were relatively common, the mortality rate associated with the recurrences was less than 30%.

Endocarditis↗
PubMedDate not supplied

Pathogenesis of experimental endocarditis.

Numerous important observations concerning the pathogenesis of infective endocarditis have been made over the past 18 years. Many of these observations have been obtained with animal models of endocarditis in which an indwelling catheter has been used to produce predisposing endocardial lesions for subsequent infection. Unlike several previously used animal models, the catheter-induced endocarditis models have many characteristics similar to infective endocarditis in humans. Key findings regarding microbial adherence and persistence and the host response to endocardial infection have led to a better appreciation of the complex issues operative in the pathogenesis of endocarditis.

Animals↗
PubMedDate not supplied

Polymicrobial infective endocarditis in the 1980s.

Clinical experience over the past decade suggests that the number of cases of polymicrobial infective endocarditis has greatly increased. We found 101 reports of cases of polymicrobial endocardial infection in a review of the English-language literature published in the 1980s. The mean patient age, 36.5 years, reflected a relatively young population, with men outnumbering women almost 2:1. Seventy-one patients were intravenous drug users; only three described recent invasive medical procedures. More than one-half of the patients had infections of the tricuspid valve, and 31 patients developed septic pulmonary emboli. The mean age of patients who died was significantly (P = .004) greater than that of those who survived. In comparison with patients who were infected with three or more organisms, those who were infected with two pathogens were almost twice (38.3% vs. 20.8%) as likely to die of their infections. These differences in mortality reflected the relative paucity of endocardial infections involving the left heart in patients with polymicrobial infections caused by three or more organisms (compared with those infected with two pathogens, P = .0032) and the variability in virulence among infecting agents.

Adult↗
PubMedDate not supplied

Infective endocarditis complicating mitral valve prolapse: epidemiologic, clinical, and microbiologic aspects.

Cases of infective endocarditis superimposed upon prolapsing mitral valves were first described two decades ago. In the intervening years 72 reports in the English-language literature have described 267 such cases. Men predominated numerically in cases occurring after the age of 40 years and in surgical and autopsy series. In cases with auscultatory abnormalities documented before the onset of infective endocarditis, murmurs-and not merely isolated systolic clicks--were usually present. Complications of infective endocarditis were relatively common, and at least 42 patients required valve replacement in the acute phase of illness or during convalescence. Although viridans streptococci were the most frequent etiologic agents (46% of cases), deaths occurred primarily among patients infected with other organisms and among those over 40 years of age. Mitral valve prolapse is increasingly being recognized as a precursor of infective endocarditis because of its high prevalence in the general population and the wider availability of echocardiographic diagnostic techniques. The risk/benefit and cost/benefit ratios for endocarditis prophylaxis in patients with prolapsing mitral valves remain controversial.

Adolescent↗
PubMedDate not supplied

Prosthetic valve endocarditis due to small-colony staphylococcal variants.

Although Staphylococcus epidermidis is a major cause of prosthetic valve endocarditis, little is known about the pathogenesis of this disease. In one case described herein, small-colony variant forms of S. epidermidis were isolated from clinical specimens obtained from a patient with prosthetic valve endocarditis. Data from the rat model of experimental endocarditis provide further evidence that small-colony variants may be operative in the production of prosthetic valve infection. Moreover, a review of the literature indicates that small-colony variants could account for the subtle clinical course after prolonged dormant infection that characterizes S. epidermidis prosthetic valve endocarditis. It is therefore hypothesized that small-colony variants of S. epidermidis may play a role in the pathogenesis of prosthetic valve endocarditis.

Animals↗
PubMedDate not supplied

Risk factors for hepatitis B virus infection in black female attendees of a sexually transmitted disease clinic.

Although recent data have supported the role of heterosexual activity in the transmission of hepatitis B virus infection in women, studies generating these data have enrolled few black women. We therefore examined black female participants attending our local health department's sexually transmitted disease clinic for the treatment of presumed uncomplicated gonorrhea in serologic and risk-factor surveys of hepatitis B virus infection. Twenty-four (17.6%) of 136 subjects tested had evidence of prior hepatitis B infection. Serologic evidence of hepatitis B infection was significantly associated with three different barometers of sexual activity that included: (1) years of sexual activity (P less than 0.005); (2) history of sexually transmitted disease (P less than 0.02); and (3) number of lifetime heterosexual partners (P less than 0.001). These data provide further support that the quantity of sexual exposure seems to be an important risk factor for hepatitis B infection in heterosexually active females.

Black People↗
PubMedDate not supplied

Evaluation of treatment with single-dose ampicillin/sulbactam with probenecid or ceftriaxone in patients with uncomplicated gonorrhea.

This study compared ampicillin/sulbactam plus probenecid with ceftriaxone for treatment of uncomplicated gonorrhea. Of the 297 men and women who were enrolled and randomized to receive either ampicillin/sulbactam (1.0 g/0.5 g) with probenecid (1 g) or ceftriaxone (0.25 g), 274 patients were evaluable. Both ampicillin/sulbactam and ceftriaxone were administered by intramuscular injections. Patients were gonococcal contacts, had positive culture results for Neisseria gonorrhoeae, or had clinical evidence of gonorrhea. Specimens for gonococcal cultures were collected from the cervix (female patients), urethra, rectum, and pharynx at pretreatment and test-of-cure visits. The presence of N. gonorrhoeae and a test-of-cure visit were required for drug efficacy analysis. Of the 274 evaluable patients, 195 (71.2%) had positive culture results for N. gonorrhoeae. Cure was achieved in 93 (94.9%) of 98 patients receiving ampicillin/sulbactam with probenecid and in 96 (99.0%) of 97 patients receiving ceftriaxone. Penicillinase-producing N. gonorrhoeae strains were found in 21 (10.8%) patients; these were eradicated by either ampicillin/sulbactam with probenecid (N = 9) or ceftriaxone (N = 12). Overall, the two drug regimens were very well tolerated and no serious adverse effects were noted. Ampicillin/sulbactam with probenecid may be useful as single-dose therapy in patients with uncomplicated genitorectal gonorrhea.

Adolescent↗