Disseminated Mycobacterium abscessus infection manifesting as fever of unknown origin and intra-abdominal lymphadenitis: case report and literature review.

Mycobacterium abscessus is a rapidly growing mycobacterium found in soil and water throughout the world. Disease in immunocompetent patients usually consists of localized skin and soft tissue infections. In contrast, disseminated disease is uncommon, usually presents with rash, and almost always occurs in an immunocompromised host. We describe an unusual case of disseminated M. abscessus infection manifesting as fever of unknown origin and intra-abdominal lymphadenitis, but without rash. Our patient responded well to amikacin and clarithromycin therapy. We also review the literature related to the diagnosis and management of this uncommon disease.

The aminoglycosides.

Despite the introduction of newer, less toxic antimicrobial agents, the aminoglycosides continue to serve a useful role in the treatment of serious enterococcal, mycobacterial, and gram-negative bacillary infections. Gentamicin, because of its low cost, remains the aminoglycoside of choice in hospitals with low levels of resistance among Enterobacteriaceae and Pseudomonas aeruginosa. Typically, it is administered in combination with beta-lactam antibiotics, but it may also be used as monotherapy for urinary tract infections or tularemia. Amikacin is useful against gentamicin-resistant gram-negative bacilli and also in the treatment of infections caused by susceptible Nocardia and nontuberculous mycobacteria. Streptomycin serves an important role in the treatment of multidrug-resistant tuberculosis and may be useful in the treatment of some gentamicin-resistant enterococcal infections. Despite an alarming increase in aminoglycoside-resistant enterococci, most institutions have noted little change in patterns of resistance among gram-negative bacilli. Although the development of newer, less toxic aminoglycosides is unlikely in the near future, single daily dosing regimens have been proposed as a convenient, cost-effective strategy. In selected patients, this novel approach seems to be as safe and effective as traditional, multidose regimens.

Localized soft-tissue infections with Mycobacterium avium/Mycobacterium intracellulare complex in immunocompetent patients: granulomatous tenosynovitis of the hand or wrist.

In immunocompetent patients, Mycobacterium avium/Mycobacterium intracellulare complex (MAC) has been associated with pulmonary infection in adults, cervical lymphadenitis in children, and disseminated infection in children and adults. MAC rarely has been recognized as a cause of localized soft-tissue infection in immunocompetent hosts. Six cases of granulomatous tenosynovitis due to MAC are reported; five cases occurred after local surgical procedures, trauma, or corticosteroid injection. In four cases, cure was achieved with combined medical and surgical intervention. In these six cases and 11 previously reported cases, both males and females were affected equally, usually in the fifth to seventh decades of life, and the distal upper extremity was predominantly involved. Surgical debridement with appropriate culture was critical for diagnosis and management. Antimycobacterial chemotherapy seemed to be a beneficial adjunctive measure in most cases but was clearly necessary for cure in only a few cases.

Coccidioidomycosis with necrotizing granulomatous conjunctivitis.

A patient with a steroid-resistant conjunctival nodule developed severe necrotizing granulomatous conjunctivitis during aggressive treatment with topical, subconjunctival, and systemic steroids. Culture of the tissue yielded Coccidioides immitis. A cavitary lesion was noted on a chest radiograph, and the same organism was recovered from a lung biopsy specimen. The granulomatous conjunctivitis was controlled only after aggressive debridement of the affected area and months of treatment with topical amphotericin B and oral fluconazole. A review of the literature suggests that subclinical ocular involvement from pulmonary coccidioidomycosis may be more common than generally believed. Conditions that blunt the host immune response may lead to a higher incidence of clinically significant ocular involvement.

Rhinoscleroma: a growing concern in the United States? Mayo Clinic experience.

Rhinoscleroma is a chronic, progressive, granulomatous infection of the upper airways caused by the bacterium Klebsiella rhinoscleromatis. Although most cases occur in developing countries, recent immigration patterns have led to an increasing number of patients with rhinoscleroma in the United States. Rhinoscleroma may mimic various inflammatory and neoplastic processes, including leprosy, paracoccidioidomycosis, sarcoidosis, basal cell carcinoma, and Wegener's granulomatosis. Current therapy consists of a combination of surgical débridement and prolonged antimicrobial therapy. Rhinoscleroma should be added to the list of opportunistic infections that can occur in patients with human immunodeficiency virus.

Trimethoprim-sulfamethoxazole.

The antimicrobial combination of trimethoprim and sulfamethoxazole is active in vitro against various gram-positive and gram-negative bacteria. Clinically, it is useful for prophylaxis and treatment of selected infections of the genitourinary, respiratory, and gastrointestinal tracts. Trimethoprim-sulfamethoxazole by itself or in combination with other antimicrobial agents is indicated for most Nocardia asteroides infections and is the antimicrobial agent of choice for Pneumocystis carinii pneumonia. The drug is relatively nontoxic in patients who do not have the acquired immunodeficiency syndrome (AIDS) and is available in both oral and intravenous forms. The native compounds and the metabolites of trimethoprim and sulfamethoxazole are excreted primarily in the urine. When the creatinine clearance is less than 30 ml/min, the dosage of trimethoprim-sulfamethoxazole should be adjusted.

Quantitative blood cultures in candidemia.

The relationship between quantitative data on peripheral blood cultures and source of infection was studied in 172 episodes of candidemia that occurred in 169 patients. Clinically, the source of candidemia was an intravascular device in 67 episodes, an extravascular source in 73 episodes, and endocarditis in 2 patients; no source was identified for the other 30 episodes. Colony counts were determined in peripheral blood specimens on the first day of candidemia by the lysis-centrifugation system. High-grade and low-grade candidemia were defined as 25 colony-forming units or more per 10 ml and 10 colony-forming units or fewer per 10 ml of blood, respectively. Of 48 episodes of high-grade candidemia, 43 (90%) were associated with an infected intravascular device; therefore, the presence of high-grade candidemia should prompt the removal of intravascular devices. In contrast, 92 of the 112 episodes of low-grade candidemia (82%) had an extravascular or an unidentified source of candidemia. In patients with infections associated with an intravascular device, colony counts declined significantly within 72 hours after removal of the device in the absence of antifungal therapy; failure to decline suggests an alternative source of persistent infection. Quantitative data from peripheral blood cultures may help distinguish intravascular from extravascular sources of candidemia and aid in assessing the response to the removal of infected intravascular devices.

The aminoglycosides.

Despite the introduction of newer, less toxic antimicrobial agents, the aminoglycosides continue to serve a useful role in the treatment of serious enterococcal and gram-negative bacillary infections. Gentamicin, because of its low cost, remains the aminoglycoside of choice in hospitals with low levels of resistance among Enterobacteriaceae and Pseudomonas aeruginosa. Amikacin is useful against gentamicin-resistant gram-negative bacilli and also in the treatment of infections caused by susceptible Nocardia and nontuberculous mycobacteria. An alarming increase in resistance to aminoglycosides among enterococci has been noted, despite little change in susceptibility patterns among gram-negative bacilli. Future efforts will need to be directed toward a better understanding of mechanisms of antimicrobial resistance and toward the prevention of aminoglycoside-induced toxicity.

Eikenella corrodens: an unusual cause of endocarditis in a patient with silent mitral valve prolapse.

A 69-year old man with clinically silent mitral valve prolapse developed infective endocarditis secondary to Eikenella corrodens after dental work. The patient required surgical removal of abscessed teeth and long-term antibiotic therapy. E. corrodens is a gram-negative coccobacillus which normally inhabits the oropharynx, gastrointestinal tract, and upper respiratory tract. The organism can cause cutaneous and abdominal abscesses, meningitis, osteomyelitis, and endocarditis. Patients with mitral valve prolapse and a pre-existent systolic murmur or Doppler echocardiographic evidence of mitral regurgitation should receive prophylactic antibiotics for any procedure associated with a bacteremia. An infection caused by E. corrodens should be considered in patients with fever after dental manipulation or in patients with "culture-negative" endocarditis.

Sporotrichosis.

Forty-nine patients with culture-proven sporotrichosis were treated between 1957 and 1986. Infections were lymphocutaneous in 36 patients, pulmonary in two, intraarticular in four, and involved multiple deep tissues in seven. Thirty-six infections involved an upper extremity. Five patients with deep infection had some evidence of being immunocompromised. Delay in diagnosis after presentation averaged 4 months overall and 25 months for those with deep infection. Ten of 12 joint infections resulted in significant functional impairment. Treatment with saturated potassium iodide solution was effective for lymphocutaneous infection. Four patients with infection of deeper tissues remain infected despite multiple operations and systemic courses of antifungal medication.

Chronic fatigue syndrome and the diagnostic utility of antibody to Epstein-Barr virus early antigen.

Antibody to Epstein-Barr virus (EBV) early antigen has been said to be the most specific indicator of symptomatic chronic EBV infection. We studied the clinical utility of this serologic test in the evaluation of patients with chronic fatigue. Thirty patients with chronic fatigue and highly elevated titers of antibody to early antigen (greater than or equal to 1:160) were compared with 30 age- and sex-matched controls with no antibody to early antigen. There were no significant differences noted between patients and controls at the initial evaluation (symptoms, physical examination, laboratory data). Follow-up information, available for 15 matched pairs, showed no differences in outcome between patients and controls. We conclude that the antibody to EBV early antigen is not helpful in the clinical evaluation of patients with chronic fatigue.

Symposium on antimicrobial agents. Metronidazole.

Metronidazole, a nitroimidazole derivative, is a unique antimicrobial agent that is active against both bacterial and parasitic organisms, although only the anaerobic members of these groups are susceptible. It has been used for the treatment of trichomoniasis for almost 30 years and is also effective in amebiasis and giardiasis. More recently, metronidazole has emerged as a principal agent for the treatment of anaerobic infections. It is highly effective against all species of anaerobes except certain non-spore-forming gram-positive bacilli and cocci and is the only agent rapidly bactericidal against the Bacteroides fragilis group. The hydroxy metabolite is 65% as effective as metronidazole and may play a major therapeutic role. Clinical studies have substantiated its efficacy for prophylaxis during elective colorectal surgical procedures and the treatment of deep abdominal sepsis (usually in combination with another agent such as an aminoglycoside). Metronidazole is the treatment of choice for bacterial vaginosis and seems to be as effective as vancomycin for treatment of Clostridium difficile-related diarrhea and colitis. Good blood levels are produced after both oral and intravenous administration, and side effects are infrequent and minimal. Metronidazole should not be taken during the first trimester of pregnancy because of concerns about mutagenicity. Tinidazole and ornidazole are recently developed nitroimidazole derivatives that have even greater antimicrobial activity than metronidazole.

Antimicrobial agents in urinary tract infections.

Urinary tract infections are commonly encountered in clinical practice and are usually readily treatable. Although many antimicrobial agents that have been available for some time remain effective in the eradication of bacteriuria, the recent introduction of the fluoroquinolone norfloxacin represents an important addition to the therapeutic armamentarium. The efficacy of single-dose therapy with antimicrobial agents such as trimethoprim-sulfamethoxazole or amoxicillin has been shown to be similar to that with conventional (7- to 10-day) treatment in women with uncomplicated lower urinary tract infections. The long-term administration of agents such as trimethoprim-sulfamethoxazole or nitrofurantoin in low doses is usually effective for suppression or prophylaxis of recurrent bacteriuria.

The aminoglycosides: streptomycin, kanamycin, gentamicin, tobramycin, amikacin, netilmicin, and sisomicin.

Despite the introduction of newer, less toxic antimicrobial agents, the aminoglycosides remain useful in the treatment of serious, hospital-acquired, gram-negative bacillary infections, especially those caused by Pseudomonas aeruginosa. Formidable nephrotoxicity and ototoxicity have limited the use of neomycin to topical or oral administration. Widespread antimicrobial resistance among Enterobacteriaceae has restricted the use of streptomycin and kanamycin to a few specific clinical situations. Gentamicin, tobramycin, and amikacin are active against a wide range of Enterobacteriaceae and many P. aeruginosa organisms. In medical centers where gentamicin resistance is prevalent, amikacin is the aminoglycoside of choice. Fortunately, amikacin resistance has not seemed to increase substantially, even in institutions where usage has been extensive for a long period. No new aminoglycoside has proved to be superior to amikacin.

Trimethoprim-sulfamethoxazole.

The antimicrobial combination of trimethoprim and sulfamethoxazole is active in vitro against a variety of gram-positive and gram-negative bacteria. Clinically, it is useful for treatment and prophylaxis of various infections of the genitourinary tract and certain infections of the respiratory and gastrointestinal tracts. Trimethoprim-sulfamethoxazole by itself or in combination with other antimicrobial agents is indicated for most Nocardia asteroides infections. It is the antimicrobial agent of choice for Pneumocystis carinii pneumonia. The drug is relatively nontoxic in patients who do not have acquired immunodeficiency syndrome (AIDS), and it is available in oral and intravenous forms. The native compounds and the metabolites of trimethoprim and sulfamethoxazole are excreted primarily in the urine. When the creatinine clearance decreases to less than 30 ml/min, the dosage of trimethoprim-sulfamethoxazole should be adjusted.

Comparison of Du Pont Isolator and Roche Septi-Chek for detection of fungemia.

The rapid detection of fungemia in hospitalized patients is imperative, particularly for those who are immunocompromised. Our laboratory compared the Roche Septi-Chek with the Du Pont Isolator for the recovery of fungi from blood. Of 23,586 matched pairs of blood cultures, 199 were positive. The Isolator detected 178 (89.4%) and the Septi-Chek detected 119 (59.7%) of all positive isolates. The mean recovery time for the Isolator and Septi-Chek was 2.2 and 4.9 days, respectively. The Isolator detected fungemia earlier than the Septi-Chek did and was the only culture system positive in 83% of 53 patients, whereas the Septi-Chek system yielded the same results in only 13% of the patients. The Isolator provides a more rapid and sensitive method for the recovery of fungi from blood.