Showing papers in "Clinical Infectious Diseases in 1992"

Toxoplasmic Encephalitis in AIDS

Abstract: Involvement of the central nervous system (CNS) is common in patients with advanced disease due to human immunodeficiency virus (HIV). Symptoms range from lethargy and apathy to coma, incoordination and ataxia to hemiparesis, loss of memory to severe dementia, and focal to major motor seizures. Involvement may be closely associated with HIV infection per se, as in the AIDS dementia complex, but is frequently caused by opportunistic pathogens such as Toxoplasma gondii and Cryptococcus neoformans or malignancies such as primary lymphoma of the CNS. The clinical presentations of attendant and direct CNS involvement are remarkably non-specific and overlapping, yet a correct diagnosis is critical to successful intervention. Toxoplasmic encephalitis is one of the most common and most treatable causes of AIDS-associated pathology of the CNS. A great deal has been learned in the last 10 years about its unique presentation in the HIV-infected patient with advanced disease. Drs. Benjamin J. Luft of the State University of New York at Stony Brook and Jack S. Remington of the Stanford University School of Medicine and Palo Alto Medical Foundation's Research Institute have studied T. gondii for many years and are two of the leading experts in the field. This commentary comprises an update of their initial review (J Infect Dis 1988;157:1-6) and a presentation of the current approaches to diagnosing and managing toxoplasmic encephalitis in HIV-infected patients.

Antimicrobial Resistance in Streptococcus pneumoniae: An Overview

Abstract: Clinical resistance to penicillin in Streptococcus pneumoniae was first reported by researchers in Boston in 1965; subsequently, this phenomenon was reported from Australia (1967) and South Africa (1977). Since these early reports, penicillin resistance has been encountered with increasing frequency in strains of S. pneumoniae from around the world. In South Africa strains resistant to penicillin and chloramphenicol as well as multiresistant strains have been isolated. Similar patterns of resistance have been reported from Spain. Preliminary evidence points to a high prevalence of resistant pneumococci in Hungary, other countries of Eastern Europe, and some countries in other areas of Europe, notably France. In the United States most reports of resistant pneumococci come from Alaska and the South, but resistance is increasing in other states and in Canada. Pneumococcal resistance has also been described in Zambia, Japan, Malaysia, Pakistan, Bangladesh, Chile, and Brazil; information from other African, Asian, and South American countries is not available. The rising prevalence of penicillin-resistant pneumococci worldwide mandates selective susceptibility testing and epidemiological investigations during outbreaks.

Candidemia in a Tertiary Care Hospital: Epidemiology, Risk Factors, and Predictors of Mortality

Abstract: Demographic information, risk factors, therapy, and outcome for all patients who had candidemia at Barnes Hospital, St. Louis, between 1 September 1988 and 1 September 1989 were retrospectively reviewed. One hundred six candidemic patients were identified, representing 0.5% of all medical and surgical discharges and 0.33% of total patient discharges. These percentages represent a 20-fold increase in the incidence of candidemia at our hospital in comparison with that during 1976-1979. Candida albicans was the most frequently isolated species (63%), followed by Candida tropicalis (17%), Candida glabrata (13%), Candida parapsilosis (6.5%), and Candida krusei (0.9%). Overall mortality was 57%, and 14 (23%) of 60 deaths occurred within 48 hours of the detection of candidemia. Mortality was associated with higher APACHE II scores (25 for nonsurvivors vs. 16 for survivors; P = .0001), the presence of a rapidly fatal underlying illness (P = .0009), and sustained positivity of blood cultures (P = .02). In cases of sustained candidemia, the isolation of non-albicans Candida species also correlated with increased mortality (8 of 8 vs. 10 of 21; P = .005). Thirty candidemic patients (28%) did not receive any antifungal therapy, and 19 (63%) of these untreated patients died. Eleven untreated patients (37%) survived without sequelae. There has been a marked increase in the incidence of candidemia in our institution that is associated with a high overall mortality. Candidemia lasting less than 24 hours was associated with a lower mortality than was that of longer duration. Severity of illness and duration of candidemia should be used as stratifying factors in prospective studies to determine optimum therapy.

Invasive Group A Streptococcus Infections

Abstract: The late 1980s have witnessed the emergence of severe group A streptococcus (GAS) infection; shock, bacteremia, and acute respiratory distress syndrome are common features, and death has been associated with this infection in 30% of patients. Such infections have now been described in all parts of the United States, Europe, and Australia and have occurred predominantly in otherwise healthy adolescents and adults. The characteristic clinical and laboratory features of the streptococcal toxic shock syndrome include deep-seated infection associated with shock and multiorgan failure. Strains of GAS isolated from patients with invasive disease have been predominantly M types 1 and 3, which produce pyrogenic exotoxin A or B or both. In this report, the clinical and demographic features of streptococcal bacteremia, myositis, and necrotizing fasciitis will be presented and compared with those of streptococcal toxic shock syndrome. Current concepts of the pathogenesis of invasive streptococcal infection will also be presented in terms of the interaction between virulence factors of GAS and host defense mechanisms. Finally, new concepts for future treatment of serious streptococcal infections will be proposed.

Emergence of Enterococcus as a Significant Pathogen

Abstract: Enterococci are components of the normal bowel flora of humans and other animals. They are often found as part of a mixed flora in intraabdominal and pelvic infections, but their role in these settings has been difficult to assess; early studies suggested that they were not important pathogens under these circumstances. Indeed, it was thought that treatments eliminating most of the other organisms from these sites of mixed infection would often lead to "spontaneous" eradication of the enterococcal component as well. As a result, the enterococci were generally considered harmless commensals. Recent studies, however, have documented the pathogenic potential of these organisms and in fact have shown convincingly that they are significant nosocomial pathogens. Enterococci are also capable of causing a variety of community-acquired infections.

Infections Caused by Streptococcus pneumoniae: Clinical Spectrum, Pathogenesis, Immunity, and Treatment

Abstract: Virtually every attempt to rank bacterial causes of community-acquired pneumonia in adults has placed Streptococcus pneumoniae at the top of the list, although the actual proportion of cases of pneumonia proven to be caused by this organism has varied from 15% to 76% in representative series. In the absence of an epidemic of meningocococcal disease, S. pneumoniae is also the most common cause of bacterial meningitis in adults and the second most common in young children, ranking behind Haemophilus influenzae type b. Blood cultures are positive in 15%-30% of cases of pneumococcal pneumonia, depending upon the population under study and, to a lesser extent, the serotype. Bacteremia-so-called primary bacteremia-may occur without an apparent source; when the disease is associated with an acute, nonspecific febrile illness in young children, harmful consequences may result if antibiotic therapy is not given. Pneumococcal empyema, endocarditis, and pericarditis occur, albeit much less commonly now than in former years. Septic arthritis, osteomyelitis, and peritonitis are seen only infrequently. Other syndromes of serious infection, such as brain abscess, pyomyositis, and peritonitis, are rare. Among less serious disease states, such as otitis media or acute sinusitis, S. pneumoniae remains the most commonly isolated bacterial pathogen when carefully aspirated material is cultured.

Infectious complications of indwelling vascular catheters.

Abstract: Vascular catheters are the most frequently used indwelling medical devices and' have become necessary tools for the successful treatment of patients with chronic or critical illness. It is estimated that vascular catheters are inserted in more than 20 million patients who are admitted to hospitals in the United States each year [1]. Several complications, however, prevent the prolonged maintenance of vascular catheters. Infection is one of the leading complications, and catheter-related septicemia represents the most frequent lifethreatening complication of vascular catheters [2-4].

Evaluation of new anti-infective drugs for the treatment of urinary tract infection. Infectious Diseases Society of America and the Food and Drug Administration.

Abstract: The term urinary tract infection (UTI) encompasses a broad range of clinical entities that share one characteristic: a positive urine culture. Clinical manifestations and responses to therapy are diverse even when comparable numbers of a particular bacterial species are identified on urine culture. These guidelines include discussion of acute uncomplicated cystitis, acute uncomplicated pyelonephritis, and complicated infections of the urinary tract. It is proposed that the finding of > or = 10(3) cfu/mL of urine defines significant bacteriuria in acute uncomplicated cystitis, > or = 10(4) cfu/mL in acute uncomplicated pyelonephritis and UTI in men, and > or = 10(5) cfu/mL in complicated UTI. The preferred clinical study design is prospective, randomized, and controlled with an active agent. Ideally, treatment with antimicrobial agents should eradicate the infecting organism, bring about the resolution of clinical signs and symptoms, have few adverse effects, and prevent reinfection.

Opportunistic Mycoses in the Immunocompromised Host: Experience at a Cancer Center and Review

Abstract: The field of opportunistic mycoses in the patient with cancer is rapidly changing Not only are fungal infections increasing in frequency in this patient population, but these infections are occurring earlier during the course of cytotoxic chemotherapy, and newer fungi are increasingly recognized as potentially lethal pathogens Candidiasis remains the most commonly encountered infection The spectrum of disease includes candidemia and acute and chronic disseminated candidiasis Pulmonary aspergillosis and disseminated aspergillosis are common and remain relatively resistant to therapy Disseminated fusariosis and trichosporosis are almost always fatal in the setting of persistent profound neutropenia Therapy for these mycoses relies on the use of amphotericin B and 5-fluorocytosine Newer antifungal agents, such as fluconazole and itraconazole, appear to exhibit good activity against a variety of fungi Newer approaches need to be tested for the treatment of the more-resistant mycoses and may include the use of maximally tolerated doses of antifungal agents, colony-stimulating factors, and combination therapy

Infections caused by Chlamydia pneumoniae strain TWAR.

Abstract: Chlamli'ldia pneuonwniae (TWAR) is a new species that causes acute infection of the respiratory tract. Pneumonia and bronchitis are the most commonly recognized diseases caused by TWAR infection. While TWAR pneumonia is usually relatively mild, the recovery period may be long. The elderly have the highest incidence of TWAR pneumonia, which may be severe if associated with underlying disease or complications. C. pneunloniae has been associated with atherosclerotic cardiovascular disease (including coronary artery disease) both by seroepidemiological studies and by demonstration of the organism in atheroma. The prototype isolate of C. pneumoniae, TW183, was obtained from a child's conjunctiva in 1965. The first isolate from acute respiratory disease, designated AR-39, was obtained in 1983. The strain name TWAR came from the labo-

Bite Wounds and Infection

Abstract: One of every two Americans will be bitten by an animal or by another person at some point. Bites account for approximately 1% of all visits to emergency rooms; injuries inflicted by dogs are most common. The bacteria involved in infection of bite wounds include Pasteurella multocida, Staphylococcus aureus, Staphylococcus intermedius, alpha-hemolytic streptococci, Capnocytophaga canimorsus, and other members of the oral flora. Anaerobic bacteria are present in approximately one-third of bite wounds and are associated with the formation of abscesses and with relatively serious infections. P. multocida is found in infections of cat bites more than 50% of the time. The bacteriology of bite wounds inflicted by exotic animals reflects the animals' oral flora. Bites inflicted by humans are often more serious than those inflicted by animals. Infections of human bites are associated with alpha-hemolytic streptococci, S. aureus, Eikenella corrodens, Haemophilus species, and (in more than 50% of cases) anaerobic bacteria. The principles of management of bite wounds are discussed.

Septicemia and Shock Syndrome Due to Viridans Streptococci: A Case-Control Study of Predisposing Factors

Abstract: Between 1972 and 1989, the incidence of viridans streptococcal bacteremia at the University of Texas M D Anderson Cancer Center in Houston increased from one case per 10,000 admissions to 47 cases per 10,000 admissions (P less than 0001) A shock syndrome characterized by hypotension, rash, palmar desquamation, adult respiratory distress syndrome, and occasionally death developed in 26% of cases of streptococcal septicemia but in only 4% of cases of septicemia involving other gram-positive bacteria (P = 0005) The risk of streptococcal infection increased with the prophylactic administration of trimethoprim-sulfamethoxazole or a fluoroquinolone (P less than 0001) and with profound neutropenia (P less than 0001) Treatment of chemotherapy-induced gastritis with antacids or with histamine type 2 (H2) antagonists was associated with a sevenfold increase in risk (P less than 001), while sucralfate therapy did not increase risk (P = 65) Streptococcal infection may result from gastric overgrowth of organisms resistant to trimethoprim-sulfamethoxazole in an antacid- or H2 antagonist-induced alkaline environment, with the gastrointestinal tract ulceration caused by antineoplastic therapy providing a convenient portal of entry In patients receiving chemotherapy, replacement of antacids or H2 antagonists by an acid-sparing regimen should be considered to preserve the natural acidic barrier to infection

Antibiotic-Associated Diarrhea

Abstract: A 53-year-old woman reports severe watery diarrhea with cramps. She is in her 7th day of a 10-day course of cefixime, prescribed for bronchitis. How should she be evaluated and treated?

Candida parapsilosis: epidemiology, pathogenicity, clinical manifestations, and antimicrobial susceptibility.

Abstract: Early reports associated Candida parapsilosis with endocarditis in intravenous narcotic addicts. More recently, this species has emerged as an important nosocomial pathogen, with clinical manifestations including fungemia, endocarditis, endophthalmitis, septic arthritis, and peritonitis, all of which usually occur in association with invasive procedures or prosthetic devices. Outbreaks of C. parapsilosis infections have been caused by contamination of hyperalimentation solutions, intravascular pressure monitoring devices, and ophthalmic irrigating solution. Experimental studies have generally shown that C. parapsilosis is less virulent than Candida albicans or Candida tropicalis. However, characteristics of C. parapsilosis that may relate to its increasing occurrence in nosocomial settings include frequent colonization of the skin, particularly the subungual space, and an ability to proliferate in glucose-containing solutions, with a resultant increase in adherence to synthetic materials. Recently developed molecular techniques may facilitate the continued exploration of the epidemiology and pathogenesis of C. parapsilosis infections.

Mycobacterial Diseases Other Than Tuberculosis

Abstract: The incidence of tuberculosis in the United States declined steadily until 1985, while at the same time, for at least the past 15 years, the frequency of disease attributable to other mycobacteria increased both in actual numbers and in the proportion of the total burden of mycobacterioses. Chronic pulmonary disease, lymphadenitis in children, skin and soft-tissue involvement, and infections of the skeletal system were predominant, and the principal etiologic agents were Mycobacterium avium/Mycobacterium intracellulare complex. Mycobacterium kansasii, Mycobacterium marinum, Mycobacterium fortuitum/Mycobacterium chelonae complex, and Mycobacterium scrofulaceum. Since 1986 disseminated disease has become not only more common, especially in association with opportunistic infections in patients with AIDS, but also attributable in part to the growing population of patients who are immunocompromised because of malignancy, receipt of an organ transplant, and administration of steroids. Treatment of these patients has been difficult because of the frequency of severe underlying conditions and the natural resistance of most of the nontuberculous mycobacteria to the presently available drugs.

beta-Lactam resistance in gram-negative bacteria: global trends and clinical impact.

Abstract: Microbial drug resistance is an inescapable consequence of the utilization of antimicrobial agents in a given environment. Nowhere is the importance of resistance more evident than among agents of the beta-lactam family. Trends toward increased resistance can be seen among fastidious gram-negative bacteria like Haemophilus influenzae, where ampicillin resistance varies from 1% to 64% globally. For Escherichia coli, ampicillin resistance has risen to > or = 50% in high-risk populations, and resistance to third-generation cephalosporins is now being seen in certain areas. Inducible beta-lactamases have been responsible for increasing multiple beta-lactam resistance among certain Enterobacteriaceae and Pseudomonas aeruginosa, and this has been associated with increased use of newer cephalosporins. Xanthomonas maltophilia with its two inducible beta-lactamases is becoming an increasingly important nosocomial pathogen, especially in areas of heavy imipenem utilization. Only through the recognition of factors associated with increasing resistance and the mechanisms responsible can strategies be designed for minimizing beta-lactam resistance.

Vascular catheter-associated fungemia in patients with cancer: analysis of 155 episodes.

Abstract: We reviewed all 155 episodes of central venous catheter-associated fungemia among inpatients at the National Cancer Institute during a 10-year period. Candida species accounted for 98% of episodes. Fungemia was documented by culture of blood drawn through catheters in 50% of cases and by culture of both catheter-drawn and peripheral blood in 39%; mortality and the rate of dissemination were similar for these two groups. Four management strategies were used: catheter removal, antifungal therapy (with amphotericin B), both, or neither; indications for the use of both modes of treatment included fever, neutropenia, long-term indwelling catheterization, positive cultures of both catheter-drawn and peripheral blood, isolation of Candida tropicalis, and fungal isolation from two or more blood cultures. Disseminated fungal infection was documented in 82% of cases with these features but also in 35% of the less severe cases treated only with catheter removal. In addition, nine (82%) of 11 cases managed only with antifungal therapy had a negative outcome (either death from disseminated infection or the recurrence of fevers and/or fungemia), a finding suggesting that intravascular catheters should be removed in fungemia. Virtually all cases of catheter-associated fungemia in patients with cancer are clinically significant and require prompt therapy with amphotericin B.

Pyomyositis in North America: Case Reports and Review

Abstract: We report two cases and review the characteristics of pyomyositis. The courses of patients who presented with pyomyositis at the Maricopa Medical Center (Phoenix) are detailed. Ninety-eight reported cases over the last 20 years in North America, found through a MEDLINE search, are summarized. Infection with the human immunodeficiency virus (HIV) may predispose the patient to pyomyositis. The onset is usually insidious with progression to large purulent collections and significant morbidity. The diagnosis is frequently suggested by findings of imaging studies. Staphylococcus aureus is responsible for most cases in tropical areas but is less frequently associated with cases in North America. Since infection with HIV predisposes patients to bacterial infections, pyomyositis will occur more frequently in this patient population. Increased awareness of the disease will improve management. Following aspiration or surgical drainage, therapy with broad-spectrum empirical antibiotics may be considered initially in the treatment of pyomyositis.

Persistent Infection with Chlamydia pneumoniae following Acute Respiratory Illness

Abstract: Chlamydia pneumoniae is emerging as a significant cause of respiratory disease, including pneumonia and bronchitis, in humans. In this recently completed study of infection due to C. pneumoniae in patients presenting with pneumonia to SUNY Health Science Center at Brooklyn, we identified two individuals for whom cultures were positive on multiple occasions over a 1-year period. To determine the frequency of persistent respiratory infection with C. pneumoniae, follow-up specimens were obtained from nine individuals with culture-documented C. pneumoniae infection. Five of these individuals had persistent infection: four had a flulike illness characterized by pharyngitis, and one had bronchitis with prominent bronchospasm. All five individuals appeared to have acute C. pneumoniae infection as determined by results of serologic tests (titers of IgM antibody for all individuals were greater than or equal to 1:16). For three patients, cultures remained positive for 11 months despite therapy with 10- to 21-day courses of tetracycline or doxycycline. These observations suggest that persistent infection with C. pneumoniae may follow acute infection and may persist for many months. Infection with C. pneumoniae may be very difficult to eradicate with use of currently available antibiotics even if there is a clinical response to therapy.

Epidemiology of Poliomyelitis in the United States One Decade after the Last Reported Case of Indigenous Wild Virus-Associated Disease

Abstract: Poliomyelitis caused by wild poliovirus has been virtually nonexistent in the United States since 1980, and vaccine-associated paralytic poliomyelitis (VAPP) has emerged as the predominant form of the disease. We reviewed national surveillance data on poliomyelitis for 1960-1989 to assess the changing risks of wild-virus, vaccine-associated, and imported paralytic disease; we also sought to characterize the epidemiology of poliomyelitis for the period 1980-1989. The risk of VAPP has remained exceedingly low but stable since the mid-1960s, with approximately 1 case occurring per 2.5 million doses of oral poliovirus vaccine (OPV) distributed during 1980-1989. Since 1980 no indigenous cases of wild-virus disease, 80 cases of VAPP, and five cases of imported disease have been reported in the United States. Three distinct groups are at risk of vaccine-associated disease: recipients of OPV (usually infants receiving their first dose), persons in contact with OPV recipients (mostly unvaccinated or inadequately vaccinated adults), and immunologically abnormal individuals. Overall, 93% of cases in OPV recipients and 76% of vaccine-associated cases have been related to administration of the first or second dose of OPV. Our findings suggest that adoption of a sequential vaccination schedule (inactivated poliovirus vaccine followed by OPV) would be effective in decreasing the risk of VAPP while retaining the proven public health benefits of OPV.

Cytomegalovirus Infection in Patients with AIDS

Abstract: Advances in the field of antiviral therapy are now occurring with increasing frequency and rapidity and often generate varying degrees of confusion among those of us whose practices are focused primarily on therapy with antibacterial agents. How to treat cytomegalovirus infections in patients infected with the human immunodeficiency virus constitutes one of the best examples of the quandaries engendered by these advances, and the topic is reviewed in this first AIDS Commentary update. Given the U.S. Food and Drug Administration's recent approval of foscarnet, this discussion is very timely; it is particularly relevant for clinicians to be made aware of current lines of thought regarding induction versus maintenance therapy, the benefits of efficacy versus adverse effects of drug-related toxicity, and the interactions between antiretroviral drugs and ganciclovir or foscarnet. Dr. W. Lawrence Drew's career in this area has been long-standing and productive, and he is one of the leading experts in the field. In this update he addresses these perplexing issues.

Trends in Antimicrobial Resistance of Clinical Isolates of Streptococcus pneumoniae in Bellvitge Hospital, Barcelona, Spain (1979–1990)

Abstract: From January 1979 to December 1990 we studied the susceptibility of 1,492 pneumococcal strains isolated from adult patients in Bellvitge Hospital, Barcelona, Spain, to nine antimicrobial agents. Among clinically significant pneumococci, the incidence of penicillin-resistant strains increased from 4.3% in 1979 to 40% in 1990, and that of erythromycin-resistant strains also rose from 0% in 1979 to 9.4% in 1990. On the other hand, the incidence of strains resistant to tetracycline decreased from 76.1% to 37.6%, as did that of chloramphenicol-resistant strains, from 56.5% to 29.4%. The incidence of co-trimoxazole-resistant strains was about 40% throughout the study. Even more alarming was the finding that about 70% of penicillin-resistant strains showed multiple resistance to non-beta-lactam antibiotics. All pneumococci were susceptible to vancomycin, and all but six were susceptible to rifampin. We observed that isolates from cerebrospinal fluid and the respiratory tract were significantly more resistant to penicillin than were isolates from blood. The majority of strains (95%) belonged to serogroups or serotypes included in the 23-valent pneumococcal vaccine and 77.6% of penicillin-resistant strains belonged to groups 23, 6, 9, and 19.

Epidemiological Features of Pertussis in the United States, 1980–1989

Abstract: From 1980 through 1989, 27,826 cases of pertussis were reported to the Centers for Disease Control, for an average annual crude incidence of 1.2 cases/100,000 population. The incidence of reported disease increased in all age groups during this period, but the increase was disproportionately large among adolescents and adults. Infants between 1 and 2 months of age were at highest risk for pertussis (average annual incidence, 62.8/100,000). Infants less than 2 months of age had the highest reported rates of pertussis-associated hospitalization (82%), pneumonia (25%), seizures (4%), encephalopathy (1%), and death (1%). Rates of complication were generally higher among unvaccinated children than among those who had received three or more doses of diphtheria-tetanus-pertussis vaccine; 64% of children 3 months to 4 years of age who had reported cases of pertussis had not been immunized appropriately for their age. Whereas control of pertussis in the United States may be further improved through increased levels of diphtheria-tetanus-pertussis vaccination among eligible infants and children, the use of acellular vaccines in adolescents and adults may also be needed to reduce the burden of pertussis in very young infants.

Pathogenesis and Treatment of Recurrent Vulvovaginal Candidiasis

Abstract: In contrast to women who experience infrequent episodes of candidal vaginitis, patients with chronic and recurrent candidal vaginitis rarely have recognizable precipitating or causal factors. Analysis of vaginal yeast isolated from women with recurrent candidal vaginitis uncommonly reveals a higher percentage of non-albicans Candida species. There is no indication that resistance to azoles is a causal factor, and no other fungal virulence factors have been identified to explain the repeated attacks. Strain typing of sequential clinical isolates by means of molecular techniques indicate a pattern of relapse due to persistent yeast in the vagina rather than frequent vaginal reinfection. Attempts to reduce the number of attacks by treating sexual partners and suppressing a gastrointestinal tract focus have failed. Recent immunological studies suggest the possibility that an acquired Candida antigen-specific immunological deficiency results in uncontrolled vaginal Candida proliferation and hence repeated clinically evident attacks. Although no definitive cure for recurrent candidal vaginitis exists, numerous therapeutic maintenance regimens with azoles are available that effectively control symptomatic infection.

A Search for Bordetella pertussis Infection in University Students

Abstract: University students with persistent cough of greater than or equal to 6 days' duration were evaluated for evidence of infection with Bordetella pertussis. Of 130 students studied during a 30-month period, 34 (26%) were found to have evidence of recent infections with B. pertussis. Infection was identified by direct fluorescent antibody assay of a nasopharyngeal specimen in one student and serologically in 33 additional subjects. B. pertussis was not recovered on culture of nasopharyngeal specimens from any subjects. Students with B. pertussis infection were identified in seven of the eight 3-month periods in which students were enrolled during the 30-month investigation, suggesting an endemic rather than epidemic pattern of infection in this university population. Illnesses of students with pertussis were similar to the illnesses of students without pertussis. The findings in this study suggest that adult populations in which endemic illness occurs at a relatively constant rate may be the reservoirs for pertussis outbreaks in susceptible children. Immunization programs in the future will need to employ booster doses for adults if complete control of B. pertussis infection is our goal.

Antimicrobial Treatment of Orthopedic Implant-related Infections with Rifampin Combinations

Abstract: The purpose of this prospective clinical study is to evaluate the role of combination chemotherapy with rifampin in the treatment of orthopedic device-related infections in which the implant could not be removed. Eleven patients with orthopedic implant-related infections due to staphylococci or streptococci were treated with the implant in situ. Each antimicrobial regimen included rifampin in combination with a beta-lactam antibiotic or ciprofloxacin. The median duration of treatment with rifampin was 86 days (range, 15-336 days) with a median follow-up of greater than 24 months after cessation of therapy. Treatment was successful for 82% of patients. Failures were associated with documented inappropriate treatment. These preliminary clinical data are supported by data from in vitro studies and animal experiments. Combination therapy with rifampin, in particular rifampin and a quinolone, should be considered for patients with orthopedic implant-related infections if the implant cannot be removed.

Helicobacter pylori: its role in disease.

Abstract: Since its discovery in 1982, Helicobacter (formerly Campylobacter) pylori has been shown to be an important pathogen of humans. This bacterium colonizes the stomach for years or decades, not days or weeks, as we usually expect for bacterial pathogens. Unlike Mycobacteriuini tuberculosis, which persists in infected hosts for extended periods but is mostly in a dormant or latent state, H. pylori causes continuous inflammation. It is this longevity and persistent lowgrade gastric inflammation that suggest that H. pylori should be considered the prototypic "slow" bacterium. In this review, I will provide a brief overview of the microbiology, epidemiology, and pathogenesis of H. pylori infection, topics that have been recently reviewed elsewhere [1, 2]. Subsequently, I will outline the relationship of this organism to peptic ulcer disease and gastric cancer, two important clinical consequences of infection, and then concentrate on a clinical approach to H. pylori infection.

Azole Antifungal Agents

Abstract: The discovery of the antifungal activity of azole compounds represented an important therapeutic advance. Miconazole, ketoconazole, and fluconazole are currently commercially available, and itraconazole has undergone extensive clinical evaluation. Because of its limited activity and toxicity, miconazole has been replaced by newer agents. Ketoconazole has proven useful in therapy for superficial infections and invasive infections caused by the pathogenic fungi. Among its disadvantages are limited absorption in the absence of gastric acid and its potential for drug-drug interactions. Fluconazole is the only azole available as oral and intravenous preparations. Unlike other azoles, it is only minimally metabolized in the liver and largely excreted in the urine as active drug. It is more effective than ketoconazole against superficial candidal infections and is the drug of choice for maintenance therapy for cryptococcal meningitis in patients infected with human immunodeficiency virus. An advantage of itraconazole is its activity against aspergillosis. It is also active against many infections caused by pathogenic fungi. Other azole compounds are at varying stages of preclinical and clinical investigation.

Meningococcal Meningitis in Sub-Saharan Africa: A Model for the Epidemic Process

Abstract: Epidemic group A meningococcal meningitis follows a unique and distinctive pattern in sub-Saharan Africa. Advances in molecular and field epidemiology have begun to elucidate the mechanisms of meningococcal meningitis epidemics. Epidemics result from a complex combination of host, organism, and environmental risk factors. Recent studies suggest that "antigenic shifts" in group A meningococcal clones may trigger an outbreak of disease by suddenly decreasing herd immunity within a population. Although the introduction of new group A meningococcal strains into a susceptible population contributes to the likelihood of an epidemic, the presence of additional environmental factors, such as low humidity and coincident respiratory tract infections, are also necessary for an epidemic to occur. Despite the unique behavior of group A meningococcal disease in sub-Saharan Africa, the application of similar methods of epidemiological analysis may be useful for determining epidemic processes for other diseases.

Optimal Duration of Therapy for Catheter-Related Staphylococcus aureus Bacteremia: A Study of 55 Cases and Review

Abstract: Over the last two decades, the optimal duration of therapy for catheter-related Staphylococcus aureus bacteremia has become the subject of controversy. A review of the literature revealed an occasional association between relapse of the infection and a short course of therapy (less than 10 days of iv antibiotic therapy). From records kept between 1983 and 1989 at the University of Florida's affiliated hospitals, we identified 55 patients with catheter-related S. aureus bacteremia. Nine patients (16%) developed acute early complications (e.g., endocarditis or osteomyelitis) while receiving antibiotics. The results of multivariate analysis showed that an early complicated course was characterized by fever and/or bacteremia that persisted for greater than 3 days after catheter removal (P = .02). The remaining 46 patients were followed up for at least 3 months. During follow-up, three of the 18 patients treated for less than 10 days with iv antibiotics developed relapsing septicemia, whereas none of the 28 patients treated for a longer period developed this condition (P = .05). Fever and/or bacteremia that persists for greater than 3 days after catheter removal and initiation of antibiotic therapy suggests an acutely complicated course requiring prolonged treatment. The duration of iv antibiotic therapy in uncomplicated cases should not be less than 10 days but need not be greater than 2 weeks.