Ceftriaxone once daily for four weeks compared with ceftriaxone plus gentamicin once daily for two weeks for treatment of endocarditis due to penicillin-susceptible streptococci. Endocarditis Treatment Consortium Group.

This randomized, multicenter, open-label study compared the efficacy and safety of monotherapy with 2 g of intravenous ceftriaxone once daily for 4 weeks with those of combination therapy with 2 g of intravenous ceftriaxone and 3 mg of intravenous gentamicin/kg once daily for 2 weeks as therapy for endocarditis due to penicillin-susceptible streptococci. Sixty-one patients were enrolled in the study. Clinical cure was observed for 51 evaluable patients both at termination of therapy and at the 3-month follow-up: 25 (96.2%) of 26 monotherapy recipients and 24 (96%) of 25 combination therapy recipients. Of the 23 patients in each treatment group who were microbiologically evaluable, 22 (95.7%) in each group were considered cured. No patient had evidence of relapse. Fourteen patients (27.5%) required cardiac surgery after initiation of treatment, including five monotherapy recipients and nine combination therapy recipients. Adverse effects were minimal in both treatment groups. We conclude that 2 g of ceftriaxone once daily for 4 weeks and 2 g of ceftriaxone in combination with 3 mg of gentamicin/kg once daily for 2 weeks are both effective and safe for the treatment of streptococcal endocarditis.

Viridans streptococcal endocarditis: clinical, microbiological, and echocardiographic correlations.

Infections caused by species within the viridans streptococci have been associated with different clinical characteristics. We studied 36 patients with viridans streptococcal endocarditis. Complications were seen in 10 (32%) of 31 patients with native valve endocarditis and four (80%) of five with prosthetic valve endocarditis and included death in two, valve replacement in six, persistent infection in three, emboli in two, and congestive heart failure in nine. Two-dimensional echocardiograms demonstrated vegetations in 26 (72%) of 36, flail mitral valves in seven, disruption of aortic valve prosthesis in one, and perivalvular abscesses in three (two Streptococcus sanguis I and one Streptococcus intermedius I). All twelve patients with native valve endocarditis who suffered complications had vegetations detected by two-dimensional echocardiography, whereas seven patients with native valve endocarditis without vegetations, as detected by two-dimensional echocardiography, had no complications (P = .03). We found no significant correlation between streptococcal species and clinical outcome. To confirm our identifications, we sent 16 identical viridans streptococcal endocarditis isolates to five institutions; only three of 16 were identified as the same species by all five institutions. We conclude that viridans streptococcal endocarditis can be associated with a virulent clinical course and that there is marked variability in species designations of individual strains by different laboratories.

Cutaneous infection at dog bite wounds associated with fulminant DF-2 septicemia.

Severe DF-2 sepsis with disseminated intravascular coagulopathy developed following dog bites in two patients who had undergone prior splenectomy. Eschariform lesions developed at the site of the animal bite in both patients. DF-2 is an unusual animal-borne slow-growing gram-negative rod that can cause fulminant sepsis in splenectomized patients. Splenectomized patients should be aware of the hazards from a dog bite. The presence of eschariform lesions in such patients should provide a clinical clue to the presence of DF-2 infection.

Two coagulase-variant forms of Staphylococcus aureus isolated from blood cultures.

Two coagulase-variant forms of Staphylococcus aureus were isolated from blood cultures of a patient with infective endocarditis. The coagulase-positive isolate was hemolytic, whereas the coagulase-negative isolate was nonhemolytic. All other properties examined were identical in both strains. Since coagulase-negative S. aureus strains have been isolated from clinical specimens, laboratories should consider using a combination of other biological properties along with coagulase production for the identification of S. aureus.

Humoral reactions in human endocarditis due to Streptococcus bovis: evidence for a common S bovis antigen.

Humoral reactions to native culture filtrates of Streptococcus bovis were studied in patients with endocarditis by means of two-dimensional crossed immunoelectrophoresis. Serum from patients with S bovis endocarditis produced eight different precipitin arcs. Lex antigen cross-reacted with sera from patients with viridans streptococcal endocarditis, and TA antigen cross-reacted with ribitol teichoic acid-positive sera from patients with Staphylococcus aureus bacteremia. One antigen, common (c), was immunoreactive with all 10 sera from S bovis-infected patients. Antibody to this antigen was not found in sera from 77 patients with gram-positive bacteremia or in 29 other control sera. Common (c) antigen was found in all strains of S bovis isolated from patients. Rabbits immunized with formalinized S bovis cells of human origin also produced antibody to common (c) antigen. Common (c) may be an important antigen of S bovis and may in fact define this organism serologically.

Morphologic and clinical observations in human infection with Babesia microti.

On admission to the hospital, a splenectomized man was found to have 85% of his erythrocytes parasitized by Babesia microti. His extensive parasitemia allowed for direct study of the morphology and ultrastructure of this organism as it appears in human infection; the need for animal inoculation and rescue techniques was thus eliminated. Positive characteristics (other than the tetrad form) that are diagnostic for babesiosis were identified. By transmission and scanning electron microscopy, parasite-induced changes in the erythrocyte membrane were observed; these alterations may explain the hemolysis seen in babesiosis. Factors that may have allowed the patient to sustain such high-level parasitemia are considered. The experience with this patient confirms that exchange transfusion is a reliable, rapid method for reduction of the parasite load in serious infection with B microti.

Human babesiosis. Clinical and therapeutic considerations.

During a two-month period, six patients from eastern Long Island were identified as having Babesia microti infection. Diagnosis was based on characteristic blood smears, hamster inoculation, or both. Symptom duration ranged from 19 to 24 days in five patients. The sixth patient, who had previously undergone splenectomy, had a more severe and prolonged illness. No specific therapy was administered to five patients. The patient who had had a splenectomy was treated with chloroquine, quinine, pentamidine, and exchange transfusions. There were no deaths. It appears that most cases of human B microti infection can be effectively managed with symptomatic and supportive care.

Blastomycosis.

Blastomycosis is the infection caused by the dimorphic fungus Blastomyces dermatitidis. The fungus was believed to be limited in distribution to North America but is found in Africa and northern South America, too. The exact natural habitat of B. dermatitidis is still uncertain with only rare reported isolation of the fungus from the environment. The inability to recover the organism from nature along with the absence of both a reliable skin test antigen and a sensitive serological test have significantly restricted our understanding of the epidemiology and the full clinical spectrum of blastomycosis. An accidental laboratory infection and several common source epidemics have enabled us to recognize that blastomycosis may be a self-limited pulmonary infection. Endogenous reactivation and opportunistic infections have been newly appreciated as clinical presentations of blastomycosis. This report will review blastomycosis with particular emphasis on these recent developments.

Cure of Haemophilus parainfluenzae endocarditis with chloramphenicol.

Haemophilus parainfluenzae is an increasingly reported cause of infective endocarditis. In vitro studies have shown this organism to bae almost universally sensitive to chloramphenicol. However, therapy for H parainfluenzae endocarditis with chloramphenicol as a single agent has been disappointing. This has been attributed to the bacteriostatic activity of chloramphenicol, whereas bactericidal agents are essential for cure of infective endocarditis. We successfully treated a patient with H parainfluenzae endocarditis with chloramphenicol alone after in vitro testing showed chloramphenicol to be bactericidal against the organism. When it is documented that chloramphenicol has bactericidal activity against the causative organism, it alone can be effective therapy for H parainfluenzae endocarditis.

Rocky Mountain spotted fever: diagnostic dilemma of the atypical presentation.

Two patients with Rocky Mountain spotted fever presented with atypical manifestations which led to a delay in diagnosis and treatment. Such clinical manifestations occurring in endemic areas during warm months should not eliminate consideration of the proper diagnosis. If RMSF cannot be ruled out, therapeutic regimens should include appropriate antimicrobial coverage.

Antibiotic-resistant Staphylococcus epidermidis in patients undergoing cardiac surgery.

Staphylococcus epidermidis isolates containing subpopulations resistant to 100 microgram of methicillin per ml were found on the chests of only 3 of 80 (4%) patients before cardiac surgery, whereas these highly resistant staphylococci were isolated from the chest wounds of 43 of 80 (54%) patients 5 days postoperatively. The percentage of patients colonized with methicillin-resistant S. epidermidis increased with time postoperatively. Methicillin-resistant postoperative isolates also contained organisms resistant to other antibiotics frequently used during these patients' hospitalizations. The percentages of patients with organisms resistant to various antibiotics were: nafcillin (100%), penicillin (100%), cephalothin (93%), cefamandole (80%), streptomycin (67%), and gentamicin (20%). Preoperative methicillin-susceptible isolates were generally susceptible to other antibiotics. Two patients with S. epidermidis prosthetic valve endocariditis caused by multiple antibiotic-resistant isolates were among the study patients. Antibiotic susceptibility patterns of each isolate from these two patients were identical to those of postoperative chest isolates from the same patient.

Prognostic value of teichoic acid antibodies in Staphylococcus aureus bacteremia: a reassessment.

Teichoic acid antibodies were measured in serum using counter immunoelectrophoresis and immunodiffusion technics with a partially purified antigen. Immunodiffusion titers of greather than or equal to 1:4 were obtained in 15/16 patients with S aureus endocarditis but in only two of 122 noninfected individuals and in no patients with endocarditis caused by other gram-positive bacteria. These same elevated titers of antibody were noted in seven of 23 patients with nonendocarditis S aureus infections. These seven patients all had either prolonged, untreated staphylococcal bacteremia or a primary site of infection which was not promptly eradicated. Six of these seven patients responded to four weeks or less of antimicrobial therapy without developing any complications. The development of high titers of teichoic acid antibodies during the course of S aureus bacteremia could not be reliably used to determine the appropriate duration of antistaphylococcal treatment.

Rifampin therapy of Staphylococcus epidermidis. Use in infections from indwelling artificial devices.

Rifampin was added to existing antibiotic regimens in two patients with Staphylococcus epidermidis infections; one patient had prosthetic valve endocarditis and the other had an infection of a CSF shunt. The addition of rifampin increased serum or CSF bactericidal titers 16-fold or greater and was correlated with a favorable clinical response. The results of tests for tube-dilution antibiotic susceptibility showed rifampin to be the most active of all antibiotics tested against the patients' organisms. The combinations of gentamicin sulfate, nafcillin sodium, or vancomycin hydrochloride with rifampin prevented the emergence of rifampin resistance in vitro and promoted enhanced killing when compared with either antibiotic alone.