Intraocular candidiasis in patients with candidemia. Clinical implications derived from a prospective multicenter study.

PURPOSE: Intraocular infection caused by Candida species can have devastating visual consequences. With the emergence of Candida as a major nosocomial pathogen, the authors investigated the prevalence of ocular lesions in patients with candidemia and evaluated risk factors for eye involvement. METHODS: This study is a prospective, multicentered, observational design. One hundred eighteen patients with candidemia were evaluated by the infectious disease service and received indirect ophthalmologic examination within 72 hours of a reported positive blood culture. Ocular findings were classified on the basis of objective, pre-determined criteria. Candida chorioretinitis was defined as the presence of focal, white, infiltrative chorioretinal lesions without vitreal involvement. Candida endophthalmitis was defined as chorioretinitis with extension into the vitreous or intravitreal "fluff balls." RESULTS: In contrast to previous studies of patients with candidemia citing prevalence rates of endophthalmitis approaching 40%, no patients were shown to have endophthalmitis. Candida chorioretinitis was seen in 9% of the patients, all of whom received antifungal agents. The observation that chorioretinitis never progressed to endophthalmitis suggests that systemic antifungal agents provided adequate ocular therapy. Risk factors for Candida chorioretinitis include fungemia with Candida albicans (versus nonalbicans species), multiple positive blood cultures, visual symptoms, and immunosuppression. Twenty percent of patients had nonspecific ocular lesions not directly related to infection. CONCLUSION: Patients with candidemia who have the risk factors noted above warrant formal ophthalmologic examination.

The efficacy of topical antibiotic prophylaxis for contaminated head and neck surgery.

This study was undertaken to determine the feasibility of using perioperative topical antibiotics in contaminated head and neck surgery and to standardize the culture methodology (both qualitative and quantitative) which could serve as bacteriologic endpoints for evaluation. Following preliminary studies to establish oral cavity indicator organisms and the impact of a single antibiotic mouthwash dose on oral microflora, 10 consecutive patients undergoing contaminated head and neck surgery were recruited into a clinical trial where clindamycin mouthwash and intraoperative irrigation containing clindamycin were used instead of traditional parenteral antibiotics. The bacteriologic efficacy of topical clindamycin was assessed by comparing the presence of four indicator microorganisms (two aerobic and two anaerobic) cultured from two oral cavity culture sites before and after antibiotic prophylaxis. The patients included in the study underwent total laryngectomy plus neck dissection(s) for laryngeal or hypopharyngeal carcinoma from 1991 to 1992 at a large university hospital specializing in head and neck cancer surgery. The main outcome measures used were the development of a postoperative wound infection and quantitative and qualitative bacteriology of the intraoperative neck wound and postoperative oral cavity. Two aerobic and two anaerobic organisms proved useful as a practical indicator for bacteriologic efficacy. Preoperative mouthwash resulted in a 99% reduction of both aerobic and anaerobic bacteria in intraoperatively cultured neck sites. Irrigation during surgery with the clindamycin solution further reduced the bacterial neck counts by an additional 90%. There was a consistent overgrowth of Hemophilus species on postoperative oral cavity cultures. No patient developed a postoperative wound infection. A topical prophylactic antibiotic alone was efficacious and safe for patients undergoing major contaminated head and neck surgery. Culture methods for assessment of bacteriologic efficacy were reproducible and cost-effective. This pilot study furnishes the ethical and scientific basis for large-scale prospective trials comparing topical versus parenteral antimicrobial agents.

Legionella pneumophila in residential water supplies: environmental surveillance with clinical assessment for Legionnaires' disease.

Although cases of community-acquired Legionnaires' disease have been epidemiologically linked to residential water supplies, the risk of acquiring Legionnaires' disease from exposure to Legionella pneumophila in residential water systems is uncertain. The residential water supplies of 218 members of the American Legion in six different geographical areas in Pittsburgh were cultured for L. pneumophila. Residents of the homes provided a recent medical history and a blood sample for detection of antibodies to legionella. A urine sample for legionella urinary antigen testing was also requested from individuals residing in legionella-positive homes and individuals with a positive antibody test. Six percent (14/218) of the homes yielded L. pneumophila (range within six areas 0-22%). Lower hot water tank temperature was significantly associated with legionella positivity (P less than 0.01). Analysis of water samples for mineral content showed no association between legionella positivity and concentrations of calcium and magnesium. Water samples from the area where 22% of the homes surveyed were positive for legionella had a higher iron content than water samples from the other areas tested. None of the individuals residing in legionella-positive homes showed elevated antibody titres to legionella or the presence of legionella antigen in urine. For the immunocompetent hosts, the risk of contracting Legionnaires' disease from exposure to contaminated household water supplies in the Pittsburgh area appears to be low.

Potable water as a cause of sporadic cases of community-acquired legionnaires' disease.

BACKGROUND: The environmental sources of sporadic, community-acquired legionnaires' disease are largely unknown, and culturing of water sources after identification of a case is currently not recommended. We conducted a prospective study of sporadic cases of community-acquired legionnaires' disease to determine whether the environmental reservoirs could be identified. METHODS: We cultured samples of potable water obtained from sources to which each of 20 patients with culture-confirmed, community-acquired legionnaires' disease had been exposed during the two weeks before the onset of symptoms. Monoclonal-antibody subtyping and restriction-endonuclease analysis were performed on the legionella isolates recovered from both the patients and the associated environmental cultures. RESULTS: For 8 of the 20 patients, isolates of Legionella pneumophila with identical subtypes were identified in cultures from both the patient and the potable water to which the patient had been exposed. The environmental reservoirs linked to the infections were the water supplies of two private residences, two nursing homes, two hospital outpatient clinics, and an industrial plant. CONCLUSIONS: Potable-water supplies that harbor L. pneumophila are an important source of community-acquired legionnaires' disease. Future studies should include attempts to identify the environmental sources of this infection.

Invasive aspergillosis in AIDS.

Invasive pulmonary aspergillosis was diagnosed in two patients with HIV infection, one with prolonged neutropenia and another receiving corticosteroid therapy. We found 17 additional cases in the literature. A known predisposing risk factor for invasive aspergillosis, eg, neutropenia, corticosteroid use, or intravenous drug abuse, was present in 79% of the cases. That the known immunologic defect of AIDS is not a major host defense against Aspergillus is supported by the empiric observation of the relative rarity of aspergillosis in patients with AIDS. The lung was the most common site of Aspergillus infection (75%), and transbronchial biopsy is diagnostically useful. Central nervous system involvement was seen in 55% and appears to be more frequent in HIV-infected patients than in other immunosuppressed patients with invasive aspergillosis. Prognosis is grim. Despite early institution of amphotericin B therapy in a few cases, the disease was uniformly fatal. Efficacy of therapy with amphotericin B plus rifampin or itraconazole remains to be evaluated. We conclude that aspergillosis is not an AIDS-related opportunistic infection.

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%.

Role of aerobic gram-negative rods, anaerobes, and fungi in wound infection after head and neck surgery: implications for antibiotic prophylaxis.

The prevention of wound infection after major contaminated head and neck surgery is a critical issue for the head and neck surgeon. The proper interpretation of cultures taken from wounds is uncertain. Multiple organisms are invariably isolated from this nonsterile site including indigenous aerobic and anaerobic flora, aerobic gram-negative rods, and fungi. We present evidence from controlled antibiotic trials that demonstrate the pathogenicity of oropharyngeal anaerobic flora. The presence of aerobic gram-negative rods and fungi generally represent colonization and antibiotic coverage need not routinely be directed at these organisms. On the other hand, the antibacterial spectrum of an agent used for head and neck would prophylaxis should include coverage for pathogenic oral flora, namely the gram-positive aerobic cocci (especially streptococci) and anaerobic bacteria.

Malignant external otitis in children.

Malignant external otitis in the pediatric population is primarily a disease of children with chronic illness or immunosuppression. The presence of severe, unrelenting otalgia, otorrhea with isolation of Pseudomonas aeruginosa, a markedly elevated erythrocyte sedimentation rate, and evidence of bone destruction on computed tomography scan should alert the clinician to the diagnosis. Unlike adults, children have a higher incidence of seventh nerve paralysis earlier in the course of the infection. They also manifest more frequent involvement of the middle ear with tympanic membrane destruction. The short interval between the onset of symptoms and facial nerve dysfunction highlights the necessity of prompt diagnosis and institution of anti-Pseudomonas therapy. Our review suggests that this destructive bacterial infection is an emerging clinical entity in children; 73% of the cases have been reported since 1980. Pediatricians should therefore be familiar with the clinical presentation of this treatable infection. Substantial morbidity could be alleviated by prompt diagnosis and early antibiotic treatment.

Legionnaires' disease in the work environment: implications for environmental health.

Legionnaires' disease is a severe pneumonia caused by the bacterium Legionella pneumophila. Outbreaks of Legionnaire's disease have occurred in hotels, hospitals, and homes but had not been reported yet in the work environment. The authors report the occurrence of Legionnaires' disease in three employees of two industrial plants. The potable water in the two plants contained high numbers of Legionella pneumophila. Monoclonal antibody subtyping of environmental and patient isolates of L. pneumophila implicated one of the plants as the source for the disease. L. pneumophila was eradicated from this plant using acidic and caustic scale removers, calcium hypochlorite, and a biocide. A systematic approach to Legionnaires' disease in the work environment, a problem which can be expected to be recognized with increasing frequency, is presented.

Bacteriologic analysis of wound infection following major head and neck surgery.

Wound infection was studied prospectively in 23 (6.5%) of 354 patients who participated in a series of antibiotic trials during major contaminated head and neck surgical procedures. Polymicrobial infection was identified in 22 (96%) of 23 cases. The most commonly encountered organisms were aerobic bacteria (91%), anaerobes (74%), and fungi (48%). All fungal infections resolved without systemic antifungal therapy. It was, therefore, concluded that the presence of fungus represented colonization. The primary treatment of an infected wound is surgical drainage accompanied by broad-spectrum antibiotic therapy to prevent sepsis. The value of postoperative wound cultures is unclear. The majority of patients who developed wound infection had a variety of organisms that appeared to be unrelated to the prophylactic antibiotic used, as well as to the particular surgery performed.

Simultaneous infection with Cryptococcus neoformans and Legionella pneumophila. In vivo expression of common defects in cell-mediated immunity.

We describe 3 patients with simultaneous infection by Cryptococcus neoformans and Legionella pneumophila. Legionnaires' disease (pneumonia) occurred shortly after onset of cryptococcal meningitis in a cardiac transplant patient receiving ciclosporin, a second patient with chronic lymphocytic leukemia and a third patient with Hodgkin's disease and autoimmune hemolytic anemia. Defects in cell-mediated immunity have been identified in patients with hematologic malignancies and in those who have received organ transplants. Clinical and experimental data suggest that the primary host defense mechanism against cryptococcal and Legionella infection involves cell-mediated immunity. Thus, the simultaneous occurrence of cryptococcal and L. pneumophila infection in these 3 patients supports experimental studies which have demonstrated common host defense mechanisms against both pathogens.

Infections caused by the Pittsburgh pneumonia agent.

Of the Legionellaceae family, Pittsburgh pneumonia agent (Tatlockia micdadei, Legionella micdadei) is second only to Legionella pneumophila in causing human pneumonia. In nosocomial infection, the patients tend to be immunosuppressed. The clinical presentation is nonspecific, although in immunosuppressed hosts the presentation may mimic that of pulmonary embolus (pleuritic chest pain, nonproductive cough, pleural-based densities on chest rontgenogram). The reservoir for the organism is water, and prevention of nosocomial infections can be accomplished by disinfection of the water supply. Diagnosis is best established by isolation of the organism from respiratory secretions by using selective, dye-containing buffered charcoal-yeast extract agar. The organisms can be acid-fast when clinical specimens are stained. Erythromycin is the antibiotic of choice, although tetracyclines, trimethoprim-sulfamethoxazole, and rifampin have also proved to be efficacious.

Susceptibility of 100 blood isolates of Pseudomonas aeruginosa to 19 antipseudomonal antibiotics: old and new.

The in vitro susceptibility of 19 antipseudomonal antibiotics, old and new, were tested against 100 blood isolates of Pseudomonas aeruginosa. The isolates were taken from consecutive bacteremic patients hospitalized in nine Pittsburgh hospitals from 1983 to 1984. Twelve percent of isolates tested were tobramycin-resistant. All of the tobramycin-resistant isolates were sensitive to apalcillin, azlocillin, aztreonam, cefsulodin, ceftazidime, ciprofloxicin, and imipenem. Two isolates were resistant in vitro to all beta-lactam antibiotics tested, but sensitive to all aminoglycosides. One hundred percent of isolates tested were susceptible to imipenem, whereas, 98% were susceptible to apalcillin and cefsulodin. The lowest MIC90 was 2 mg/L for ciprofloxicin. Tolerance of P. aeruginosa (MIC90/MBC90 ratio greater than 32) was not observed for any antimicrobial agent.

Legionella species as hospital-acquired respiratory pathogens.

Nosocomial pneumonia caused by legionella is an increasingly recognized entity. Legionella sp responsible for documented nosocomial disease include Legionella pneumophila, Tatlockia micdadei, Legionella bozemanii, Legionella dumoffi and Legionella oakridgensis. The clinical presentation is nonspecific although diarrhea occurs frequently. Hyponatremia occurs significantly more frequently in legionnaires' disease than pneumonias caused by other agents. Chest roentgenographic findings are nonspecific, although cavitation can be seen in immunosuppressed patients. Laboratory methods require the use of direct fluorescent antibody (DFA) stains, culture using selective media, serologic testing, and detection of antigen in urine. The DFA test is not sensitive; however, it does correlate with the severity of disease. Culture from sputa is now feasible. Bronchoalveolar lavage is a promising technique for obtaining specimens. The ideal specimen for culture is that obtained by transtracheal aspiration, which bypasses oropharyngeal contamination. Combination therapy of erythromycin and rifampin is recommended for selected patients. Because the source of the organism is the hospital water distribution system, we recommend routine environmental surveillance, especially in hospitals in which organ transplants are performed. The role of cooling towers as a vector for dissemination of the organism is disputed. Disinfection of the water supply can be accomplished by using heat eradication. Chlorination has generally proven unsatisfactory because of organism persistence as well as corrosive damage to the plumbing system from the chlorine. Both physician awareness and availability of specialized laboratory testing are necessary for the detection of cases.