Decision Making in Fuzzy Discrete Event Systems1

The primary goal of the study presented in this paper is to develop a novel and comprehensive approach to decision making using fuzzy discrete event systems (FDES) and to apply such an approach to real-world problems. At the theoretical front, we develop a new control architecture of FDES as a way of decision making, which includes a FDES decision model, a fuzzy objective generator for generating optimal control objectives, and a control scheme using both disablement and enforcement. We develop an online approach to dealing with the optimal control problem efficiently. As an application, we apply the approach to HIV/AIDS treatment planning, a technical challenge since AIDS is one of the most complex diseases to treat. We build a FDES decision model for HIV/AIDS treatment based on expert's knowledge, treatment guidelines, clinic trials, patient database statistics, and other available information. Our preliminary retrospective evaluation shows that the approach is capable of generating optimal control objectives for real patients in our AIDS clinic database and is able to apply our online approach to deciding an optimal treatment regimen for each patient. In the process, we have developed methods to resolve the following two new theoretical issues that have not been addressed in the literature: (1) the optimal control problem has state dependent performance index and hence it is not monotonic, (2) the state space of a FDES is infinite.

Using an admissions exam to predict student success in an ADN program

Nursing faculty strive to admit students who are likely to successfully complete the nursing curriculum and pass NCLEX-RN. The high cost of academic preparation and the nursing shortage make this selection process even more critical. The authors discuss how one community college nursing program examined academic achievement measures to determine how well they predicted student success. Results provided faculty with useful data to improve the success and retention of nursing.

An overview of HIV infection and AIDS: etiology, pathogenesis, diagnosis, epidemiology, and occupational exposure

Thanks to a worldwide collaborative effort among health care providers, academia, governments, and industry, our knowledge base about infection caused by the human immunodeficiency virus (HIV) has expanded exponentially. During the past 2 decades, we have learned about its pathogenesis, virology, immunology, epidemiology and treatment. In the developed world, the approach to persons with HIV disease has evolved from palliative disease care to use of a chronic disease model, where survival is measured by decades, not months or years. More and more, clinical decision-making for HIV-infected patients is driven by comorbidities, including cardiothoracic disease. Thus, our clinically stable HIV population is increasingly accessing those health care services required by any maturing population, including the usual services of cardiothoracic surgeons. In this article, we review the basic facts of HIV disease, with an emphasis on occupational risks and infection control procedures.

Treatment of HIV disease in the new millennium

Highly active antiretroviral therapy (HAART), which typically consists of 3-drug combinations of antiretroviral agents, has decreased dramatically the incidence of AIDS and death among HIV-infected persons in the United States. HIV infection no longer is viewed as a death sentence. Complete suppression of viral replication through the use of HAART can reverse the immune deficits formerly thought to be inevitable. However, drug toxicity, cross-resistance, and less-than-perfect adherence to prescribed antiretroviral regimens make the medical management of the HIV-infected person complex. An overview of the current approach to antiretroviral therapy is presented in this article.

Recurrence of Mycobacterium avium infection in patients receiving highly active antiretroviral therapy and antimycobacterial agents

The known effects of highly active antiretroviral therapy (HAART) on opportunistic infections (OIs) range from immune restoration disease to remission of specific OIs. In the present study, Mycobacterium avium complex infection recurred in 3 patients receiving antimycobacterial therapy and HAART. At the time of the initial M. avium infection, the mean CD4 cell count was 22.3 cells/mm3, and the HIV viral load was 181,133 copies/mL. Relapse occurred a mean of 14. 3 months after the first episode; the mean follow-up CD4 cell count was 89/mm3 (mean elevation of 66 cells/mm3), and the HIV viral load was <400 copies/mL in each patient. M. avium was isolated from blood (1 patient), blood and lymph node (1), and small-bowel tissue (1). M. avium infection may recur as a generalized or focal disease in those who are receiving antimycobacterial agents but whose HAART-associated CD4 cell recovery, although significant, is not optimal.

Acetylator phenotype and genotype in patients infected with HIV: discordance between methods for phenotype determination and genotype

The acetylator phenotype and genotype of AIDS patients, with and without an acute illness, was compared with that of healthy control subjects (30 per group). Two probe drugs, caffeine and dapsone, were used to determine the phenotype in the acutely ill cohort. Polymerase chain reaction amplification and restriction fragment length polymorphism analysis served to distinguish between the 26 known NAT2 alleles and the 21 most common NAT1 alleles. The distribution (%) of slow:rapid acetylator phenotype seen among acutely ill AIDS patients differed with the probe substrate used: 70:30 with caffeine versus 53:47 with dapsone. Phenotype assignment differed considerably between the two methods and there were numerous discrepancies between phenotype and genotype. The NAT2 genotype distribution was 45:55 slow:rapid. Control subjects, phenotyped only with caffeine, were 67:33 slow:rapid versus 60:40 genotypically. Stable AIDS patients, phenotyped only with dapsone, were 55:45 slow:rapid versus 46:54 genotypically. Following resolution of their acute infections, 12 of the acutely ill subjects were rephenotyped with dapsone. Phenotype assignment remained unchanged in all cases. The distribution of NAT1 alleles was similar in all three groups. It is evident from the amount of discordance between caffeine phenotype and dapsone phenotype or genotype that caution should be exercised in the use of caffeine as a probe for NAT2 in acutely ill patients. It is also clear that meaningful study of the acetylation polymorphism requires both phenotypic and genotypic data.

Is hydroxylamine-induced cytotoxicity a valid marker for hypersensitivity reactions to sulfamethoxazole in human immunodeficiency virus-infected individuals?

Hypersensitivity (HS) reactions to sulfonamides and sulfones continue to limit their use in human immunodeficiency virus (HIV)-infected individuals. In vitro cytotoxicity of hydroxylamine metabolites toward peripheral blood mononuclear cells (PBMCs) has been proposed as a marker for these HS reactions. To test the validity of this in vitro system, we determined the selective susceptibility of PBMCs from HIV-infected patients to the cytotoxic effects of hydroxylamine metabolites of sulfamethoxazole (SMX) and dapsone (DDS). Concentration-cytotoxic response data were collected using PBMCs from 12 sulfa-HS (10 SMX-HS and 2 SMX/DDS-HS) and 10 sulfa-tolerant HIV-infected individuals. Although sulfamethoxazole hydroxylamine (SMX-NOH) and dapsone hydroxylamine (DDS-NOH) both caused concentration-dependent increases in cell death, DDS-NOH was significantly more potent in each subject (P <.0001). A comparison of a variety of mean data for sulfa-HS and -tolerant patient populations failed to demonstrate the increased susceptibility of PBMCs from HS patients, noted by others, to either SMX-NOH or DDS-NOH. Moreover, any trend toward an increased susceptibility of PBMCs from HS patients was eliminated when adjusted for control cell death. PBMCs from sulfa-HS patients showed significantly greater susceptibility to the stress of short term in vitro incubation (P <. 02). Mean (S.D.) vehicle control cell death values were 24.1% (7.6%) for HS patients and 17.1% (4.4%) for tolerant patients. No significant correlation was observed between hydroxylamine-induced or control cell death and any of the recorded clinical parameters. Although several potential reasons are proposed to explain the disparity with past investigations, the data suggest that in vitro cytotoxicity is not a valid marker for HS reactions in HIV-infected individuals using currently accepted experimental procedures.

Cutaneous infections due to Acanthamoeba in patients with acquired immunodeficiency syndrome

We report 2 cases of cutaneous Acanthamoeba infection in patients with acquired immunodeficiency syndrome. The disease, which manifests as subcutaneous nodules, mimics other more commonly encountered clinical entities. A high index of suspicion, familiarity with the clinical and histologic appearance of skin lesions, and communication between clinicians and pathologists are crucial for early diagnosis and treatment of this potentially fatal infection.

The impact of human immunodeficiency virus infection on drug-resistant tuberculosis

Infection with human immunodeficiency virus (HIV) has been associated with increased rates of single- and multidrug-resistant (MDR) tuberculosis in the New York City area. In order to examine the relationship of HIV infection to drug-resistant tuberculosis in other selected regions of the United States, we established a registry of cases of culture-proven tuberculosis. Data were collected from sites participating in an NIH-funded, community-based HIV clinical trials group. All cases of tuberculosis, regardless of HIV status, which occurred between January 1992 and June 1994 were recorded. Overall, 1,373 cases of tuberculosis were evaluated, including 425 from the New York City area, and 948 from seven other metropolitan areas. The overall prevalence of resistance to one or more drugs was 20.4%, and 5.6% of isolates were resistant to both isoniazid and rifampin (MDR). In the New York City area, HIV-infected patients were significantly more likely than persons not known to be HIV-infected, to have resistance to at least one drug (37% versus 19%) and MDR (19% versus 6%). In other geographic areas, overall drug resistance was 16%, and only 2.2% of isolates were MDR. In multiple logistic regression analyses, HIV infection was shown to be a risk factor for drug-resistant tuberculosis, independent of geographic location, history of prior therapy, age, and race. We concluded that HIV infection is associated with increased rates of resistance to antituberculosis drugs in both the New York City area and other geographic areas. MDR tuberculosis is occurring predominantly in the New York City area and is highly correlated with HIV infection.

Ophthalmologic manifestations of acquired immune deficiency syndrome-associated progressive multifocal leukoencephalopathy

PURPOSE

Progressive multifocal leukoencephalopathy (PML) is increasingly described as a late complication of the acquired immune deficiency syndrome (AIDS). The purpose of this study is to evaluate retrospectively the ophthalmologic, clinical, and investigational aspects of AIDS-associated PML.

METHODS

The authors evaluated ten patients in whom ophthalmologic manifestations developed in the course of AIDS-associated PML. Findings at clinical examination and their progression over time, neuroimaging correlates, the results of pathologic investigation, and visual outcomes were reviewed.

RESULTS

Progressive multifocal leukoencephalopathy was the AIDS-defining illness in six of ten patients. Homonymous visual field defects were the presenting symptom in three patients and detected in six patients overall. Occipital blindness developed in one patient. Cerebellar signs and brain stem nuclear and supranuclear palsies also were common. Confluent white matter lesions with increased intensity on T2-weighted magnetic resonance imaging were supratentorial in seven patients and infratentorial in three patients. With incomplete data, the median survival time was 3 months from PML onset. Histopathologic confirmation of PML diagnosis was available for nine of the ten patients.

CONCLUSIONS

The development of progressive retrochiasmal visual field defects, supranuclear and nuclear cranial nerve palsies, or nystagmus ataxia in the relatively young patient should alert the ophthalmologist to the possibility of PML, particularly in the presence of long-tract central nervous system signs or dementia. Progressive multifocal leukoencephalopathy will often be human immunodeficiency virus associated. Human immunodeficiency virus encephalopathy, cerebral toxoplasmosis, lymphoma, and infarction need to be discriminated. Effective therapy is required urgently for this devastating disease.

Response of CD4 lymphocytes and clinical consequences of treatment using ddI or ddC in patients with advanced HIV infection

The value of CD4 lymphocyte counts as a surrogate marker in persons with advanced human immunodeficiency virus infection during antiretroviral treatment was assessed using longitudinal models and data from the Terry Beirn Community Programs for Clinical Research on AIDS didanosine/zalcitabine trial of 467 HIV-infected patients. Patients with AIDS or two CD4 counts of < or = 300 who fulfilled specific criteria for zidovudine intolerance or failure were randomized to receive either 500 mg didanosine (ddl) daily or 2.25 mg zalcitabine (ddC) per day. Absolute CD4 counts were recorded at study entry and at as many as four visits. Patients were followed for clinical disease progression and survival. At 2 months, the difference in mean CD4 count from baseline was +15.4 cells/mm3 in the ddI group but -1.3 cells/mm3 in the ddC group. Patients assigned to ddI had a greater chance of a CD4 response at 2 months than those on ddC, yet only those in the ddC group with a response showed significant improvement in progression of disease or survival compared with ddC nonresponders, ddI responders, and ddI nonresponders (p = 0.03). We conclude that a CD4 response does not necessarily correlate with improved outcome and is therefore not a useful surrogate marker in these patients.

Frequencies of opportunistic diseases prior to death among HIV-infected persons. Community Programs for Clinical Research on AIDS

OBJECTIVES

To describe the complete history of major opportunistic events experienced by 1883 HIV-infected persons prior to and specifically within 6 months of death, and to determine whether the frequency of specific events varies according to demographic characteristics, risk behaviors or geographic location.

DESIGN

Descriptive case series.

METHODS

Of 6682 HIV-infected individuals enrolled in studies sponsored by the Community Programs for Clinical Research on AIDS between September 1990 and June 1994, 1883 died during follow-up. A complete history of AIDS-defining events was determined for these patients by combining medical history data obtained at the time of enrollment, new events that occurred during follow-up, and causes of death.

RESULTS

The most common opportunistic AIDS-defining events these 1883 patients experienced before death were Pneumocystis carinii pneumonia (PCP; 45%), Mycobacterium avium complex (MAC; 25%), wasting syndrome (25%), bacterial pneumonia (24%), cytomegalovirus (CMV) disease (23%) and candidiasis (esophageal or pulmonary; 22%). In addition, 47% of patients experienced two or three AIDS-defining events before death, and 22% experienced four or more events. In the 6 months prior to death, 22% of patients had PCP, 21% had MAC, and 20% had CMV disease. Significant sex and ethnic differences were found: bacterial pneumonia occurred more often before death in women compared with men; fewer blacks and Latinos than whites experienced Kaposi's sarcoma (KS); and fewer blacks than whites had CMV disease before death. The percentage of patients with KS and CMV also varied by risk behavior. The frequency of 10 opportunistic diseases varied by geographic region after adjustment for demographic characteristics and risk behavior. Of note, many more patients in northeastern USA had tuberculosis and fewer had MAC.

CONCLUSION

A large percentage of individuals with HIV infection experienced multiple AIDS-defining opportunistic diseases before death. PCP, MAC, wasting syndrome, bacterial pneumonia, CMV disease, and candidiasis (esophageal or pulmonary) account for a substantial proportion of morbidity associated with HIV infection. More diseases varied by geographic location than by demographic characteristics or risk behavior of patients. Continued research on the etiology and prevention of these diseases and how they relate to one another should be a high priority.

Bacteriology of sinusitis in human immunodeficiency virus-positive patients: implications for management

The bacteriology of sinusitis in human immunodeficiency virus (HIV)-infected patients has been only sporadically reported. In this study, we report the results of cultures taken from 12 HIV patients with refractory chronic sinusitis who underwent surgery. Nine of the 12 patients had positive cultures with 16 isolates and 5 patients having multiple isolates. Five of the 12 patients grew out atypical or opportunistic infections not responsive to standard medical therapy, including 3 patients with cytomegalovirus, 1 with Aspergillus fumigatus, and 1 with Mycobacterium kansasii. These results suggest the need for aggressive medical care for HIV-infected patients with sinusitis and early intervention for tissue cultures in patients who do not respond to standard antibiotic regimens.

Evaluation and treatment of HIV-related illnesses in the emergency department

Individuals infected with the human immunodeficiency virus (HIV) present frequently to emergency departments for treatment of complications. A working knowledge of the multisystem problems seen in HIV-infected patients is essential for the emergency physician. These problems are reviewed, with an emphasis on the respiratory, central nervous system, and gastrointestinal complications seen in patients with the acquired immune deficiency syndrome (AIDS). A practical approach is offered for management of febrile episodes and the other problems an emergency physician is likely to encounter.

A comparative trial of didanosine or zalcitabine after treatment with zidovudine in patients with human immunodeficiency virus infection. The Terry Beirn Community Programs for Clinical Research on AIDS

BACKGROUND

Both didanosine and zalcitabine are commonly used to treat patients with human immunodeficiency virus (HIV) infection who cannot tolerate zidovudine treatment or who have had disease progression despite it. The relative efficacy and safety of these second-line therapies are not well defined.

METHODS

In this multicenter, open-label trial we randomly assigned 467 patients who previously received zidovudine and had 300 or fewer CD4 cells per cubic millimeter or a diagnosis of the acquired immunodeficiency syndrome (AIDS) to treatment with either didanosine (500 mg per day) or zalcitabine (2.25 mg per day).

RESULTS

After a median follow-up of 16 months, disease progression or death occurred in 157 of 230 patients assigned to didanosine and 152 of 237 patients assigned to zalcitabine, for a relative risk of 0.93 for the zalcitabine group as compared with the didanosine group (P = 0.56), which decreased to 0.84 (P = 0.15) after adjustment for the CD4 count, Karnofsky score, and presence of AIDS at base line. There were 100 deaths in the didanosine group and 88 in the zalcitabine group, for a relative risk of 0.78 (P = 0.09) and an adjusted relative risk of 0.63 (P = 0.003). A majority of patients in each group (66 percent) had at least one adverse event during treatment (153 patients taking didanosine and 157 taking zalcitabine). Peripheral neuropathy and stomatitis occurred more often with zalcitabine and diarrhea and abdominal pain more frequently with didanosine.

CONCLUSIONS

For patients with HIV infection who have not responded to treatment with zidovudine, zalcitabine is at least as efficacious as didanosine in delaying disease progression and death.

Comparative analysis of three antifungal susceptibility test methods against prospectively collected Candida species

We performed antifungal susceptibility tests with cilofungin (LY121019), amphotericin B, and flucytosine against 38 strains of yeasts from patients with esophagitis or fungemia either before, during, or after treatment with cilofungin. Tests were performed using a macrobroth dilution method similar to that proposed by the National Committee for Clinical Laboratory Standards (M27-P) and two microbroth methods. For cilofungin and amphotericin B, minimum inhibitory concentrations from microbroth tests using Antibiotic Medium 3 (AM3) were systematically lower than results from the other two methods that utilized RPMI-1640 medium (RPMI). AM3 did not provide any greater degree of in vitro correlation with clinical results than did RPMI. We conclude that cilofungin and possibly other congeners of the echinocandin class of antifungal agents can effectively be studied using the proposed National Committee for Clinical Laboratory Standards method.

HIV testing in patients with tuberculosis. Physician response to national recommendations

The epidemic of human immunodeficiency virus (HIV) disease has contributed to the resurgence of tuberculosis in the United States. For clinical and public health reasons, the Advisory Council for the Elimination of Tuberculosis has recommended that all patients with tuberculosis be tested for HIV antibodies. We reviewed the medical records of all patients with tuberculosis in whom a diagnosis was made at a Detroit medical center from July 1, 1986 to June 30, 1990, before and after recommendations were issued. Of 195 patients, 69 (35.4%) were tested for HIV antibodies: 73.7% of 57 patients whose medical records documented risk behaviors for HIV infection, and 19.6% of 138 patients who denied high-risk behaviors or whose medical records contained no risk information (relative risk of testing among patients with documented risk factors compared with others, 3.8; 95% confidence interval, 2.6 to 5.5). Testing of patients who denied risk behaviors or had no information in their records increased from 14.9% in the first 12 months to 30.4% in the last (p = 0.08, test for trend). In this population, national recommendations appear to have stimulated HIV testing, although most patients still are not being tested.

Detection of Pneumocystis carinii in a rat model of infection by polymerase chain reaction

The polymerase chain reaction (PCR) was employed to detect Pneumocystis carinii in organs of infected rats. Using a pair of oligonucleotides designed to the dihydrofolate reductase (DHFR) gene of rat P. carinii, specific amplification of an expected 415 bp region of P. carinii DHFR DNA of this organism was achieved, while no amplification occurred with the human, Candida albicans, and Mycobacterium avium and tuberculosis DNAs. Using rat P. carinii isolated from in vitro cultures and infected lung homogenates, the minimum detection level by PCR on an ethidium bromide gel was about 200 organisms and by Southern analysis with radiolabelled DHFR probe the detection level improved to 20 organisms. This level of sensitivity is sufficient to detect P. carinii specific band on the gel in infected rat lung and other organs. This PCR technique is potentially useful for detecting P. carinii in bronchoalveolar lavage (BAL) fluids of AIDS patients and for quantifying the organisms in tissues and in in vitro cultures where a high background with conventional stains makes it harder to determine the number of organisms.

Fungemia caused by Candida species and Torulopsis glabrata in the hospitalized patient: frequency, characteristics, and evaluation of factors influencing outcome

We reviewed 135 cases of candidemia occurring between 1983 and 1986 to examine oncologic and nononcologic populations and assess factors for survival. Candida albicans was the most common species (51%); Candida tropicalis occurred most frequently in leukemia patients (57%), whereas Candida parapsilosis and Torulopsis glabrata were associated with solid tumors and nononcologic diseases. Risk factors identified were: preceding surgery, antibiotics, cannulas, and steroids in solid tumor and nononcologic diseases; and chemotherapy and neutropenia with hematologic malignancies. Even transient cannula-associated candidemia was not a benign process. Intravenous cannulas were common portals of entry (39%) in debilitated patients without cancer (59%) and were associated with high mortality (55%). Overall mortality was 59%, candidemia directly contributing to death in 75% of cases. In patients with candidemia, failure to initiate therapy with amphotericin B had a negative influence on outcome, whereas analysis of the entire group identified severity of underlying illness as the dominant cofactor influencing outcome.

Enhanced efficacy of nucleoside analogs and recombinant alpha interferon in weanling mice lethally infected with herpes simplex virus type 2

Weanling ICR Swiss mice were inoculated intranasally with a lethal dose of herpes simplex virus type 2, and treated with either vidarabine, vidarabine-5'-monophosphate, acyclovir or a hybrid recombinant human alpha interferon which is active in murine tissues. Treatment with antiviral drugs was initiated 2, 24, 48, 72 or 96 h following virus inoculation. Single drug treatment showed little effect on mortality, with only acyclovir showing some slight reduction. Four dual drug combinations (vidarabine/acyclovir; vidarabine/interferon; vidarabine 5'-monophosphate/acyclovir and vidarabine 5'-monophosphate/interferon) were all associated with marked reductions of mortality when treatment was begun at 2 h, and this beneficial effect increased further when therapy was delayed until 24 or 48 h following virus inoculation. However, the combination of acyclovir/interferon was consistently toxic to the mice, unless a reduction in dosages was employed. These results suggest that certain antiviral combinations might be useful for serious human infections caused by herpes simplex virus.

Comparison of the activity of antibiotic combinations in vitro with clinical outcome and resistance emergence in serious infection by Pseudomonas aeruginosa in non-neutropenic patients

Techniques for demonstrating synergy in vitro were compared in testing different beta-lactam-aminoglycoside combinations against 30 isolates of Pseudomonas aeruginosa. Poor concordance was noted among the results from chequerboard and 6 h and 24 h time-kill methods. Comparison of in-vitro synergy results with clinical outcome in 14 patients with pseudomonas infection showed that antagonism in the 24 h time-kill method was the most reliable prognostic indicator of clinical and bacteriological outcome. Although more than 70% of patients were cured clinically with cefsulodin or ticarcillin with tobramycin or amikacin, pseudomonas resistant to the beta-lactam emerged in 7 of 14 patients (50%); of those seven, three had poor clinical outcome. The rationale of adding aminoglycoside to beta-lactams against P. aeruginosa to prevent emergence of resistance needs closer examination.

Legionella feeleii-associated pneumonia in humans

Legionella feeleii has been implicated by serologic studies as the causative agent in an outbreak of Pontiac fever and has been recovered from an institutional water source. Pneumonia caused by this agent has not been described previously. The authors have isolated L. feeleii from two immunosuppressed patients with community-acquired pneumonia and from an institutional water source. One patient survived after treatment with erythromycin. The other patient was leukopenic and died of pneumonia. Isolates exhibited typical cultural and biochemical features of L. feeleii and reacted with L. feeleii serogroup 1 antiserum. L. feeleii serogroup 1 is now known to cause not only Pontiac fever but also pneumonia in humans.

Bacteremia in narcotic addicts at the Detroit Medical Center. II. Infectious endocarditis: a prospective comparative study

For one year all narcotic addicts admitted to the Detroit Medical Center with infectious endocarditis (74 cases) were compared with a control group of bacteremic addicts who had other infections (106 cases). Endocarditis was caused by Staphylococcus aureus (60.8% of cases), streptococci (16.2%), Pseudomonas aeruginosa (13.5%), mixed bacteria (8.1%), and Corynebacterium JK (1.4%). S. aureus endocarditis most frequently involved the tricuspid valve; streptococci infected left-sided valves significantly more often than other organisms (P = .001). Biventricular and multiple-valve infections were commonest in patients with pseudomonas endocarditis (P = .05). Two-dimensional echocardiography, when combined with an abnormal chest roentgenogram, was highly predictive of endocarditis. Bacteremia in the absence of endocarditis was associated with primary skin and soft tissue infection, mycotic aneurysm at the site of narcotic injection, septic arthritis, septic thrombophlebitis, pneumonia, osteomyelitis, mediastinal abscess, and unclassified infection. Polymicrobial bacteremia in the nonendocarditis group was associated with markedly increased morbidity. Mild hyponatremia occurred in 41% of all patients and was also associated with significantly increased morbidity. Analysis of the two groups disclosed similarities and differences with implications for the pathophysiology and treatment of addicts with bacteremic infection.

Bacteremia in narcotic addicts at the Detroit Medical Center. I. Microbiology, epidemiology, risk factors, and empiric therapy

The changing microbiology of bacteremia among narcotic addicts in Detroit raised concerns about current presumptive antimicrobial therapy. In a one-year study of incidence, microbiology, sites, and risk factors, 180 bacteremic addicts (15% of addict-related admissions) were followed prospectively. Cases of bacteremia were caused by methicillin-sensitive Staphylococcus aureus (33%), methicillin-resistant S. aureus (MRSA, 24%), streptococci (20%), mixed organisms (11%), Pseudomonas aeruginosa (9%), and miscellaneous other single organisms (3%). Endocarditis (41%) and abscess or cellulitis (34%) were usually found. Multivariate analysis of host factors and addiction habits yielded results predictive of bacterial species but not of infection sites. Previous hospitalization, long-term addiction, and nonprescribed antibiotic use were associated with MRSA acquisition (odds ratio, 8.6:1). All addicts with polymicrobial or P. aeruginosa bacteremia abused pentazocine and tripelennamine (P = .05). Many of the addicts with streptococcal bacteremia were women who did not abuse antibiotics (odds ratio, 20.7:1). Physicians inappropriately prescribed empiric antibiotics for 67 of 72 addicts with MRSA, P. aeruginosa, or polymicrobial infection. The results of regression analysis suggest that, guided by the patient's history, the physician can prescribe appropriate empiric antimicrobial therapy for bacteremia in the febrile addict in Detroit.

Comparative activities of combinations of acyclovir, vidarabine or its 5'-monophosphate, and cloned human interferons against herpes simplex virus type 2 in human and mouse fibroblast cultures

Human interferon-alpha A/D (Bgl), an alpha-hybrid cloned interferon, displays activity in both human and mouse cell lines. We measured the effects of this interferon in double and triple combinations with acyclovir, vidarabine or its 5'-monophosphate against herpes simplex virus type 2 in mouse and human fibroblasts. A 75% cytopathic effect reduction assay employing a modified checkerboard technique was used. Results in human fibroblasts were compared with those obtained when recombinant human interferon-alpha 2 was substituted for the hybrid. Combinations of the hybrid interferon and nucleoside antiviral agents evoked comparable synergistic isobolograms and fractional inhibitory concentration indices in human and mouse cells versus herpes simplex virus type 2. Similar interactions were found when human interferon-alpha 2 was substituted. Uninfected cells treated with the tested combinations showed no toxicity. These data suggest that combinations of recombinant human interferon-alpha A/D (Bgl) and nucleosides in mouse models of herpes infection deserve study.

Comparative activities of selected combinations of acyclovir, vidarabine, arabinosyl hypoxanthine, interferon, and polyriboinosinic acid-polyribocytidylic acid complex against herpes simplex virus type 2 in tissue culture and intravaginally inoculated mice

The effects of double and triple combinations of acyclovir (ACV), adenine arabinoside (ara-A), arabinosyl hypoxanthine, or interferon on herpes simplex virus type 2 in mouse embryo fibroblasts were measured. These in vitro data were compared with results obtained in mice infected intravaginally with herpes simplex virus type 2 and treated intraperitoneally with low- and high-dose combinations of ACV, ara-A, or polyriboinosinic-polyribocytidylic acid(poly-L-lysine)carboxymethylcellulose complex [poly IC(LC)], an interferon inducer. Although all double combinations and one triple combination evoked synergistic reactions in vitro, results did not necessarily predict in vivo observations. In vivo synergy was observed when combinations of ACV and ara-A and low doses of ara-A-ACV-poly IC(LC) were used. However, toxicity was seen with full-dose nucleoside-poly IC(LC) doublets. The full-dose ACV-ara-A combination completely prevented progression beyond vaginitis, with all animals surviving. The ara-A-ACV results observed in mice, together with in vivo data of others, suggest that this combination might prove clinically useful for certain herpes simplex virus type 2 infections.

Successful therapy for rhinocerebral mucormycosis with associated bilateral brain abscesses

A case of extensive rhinocerebral mucormycosis, with associated bilateral brain abscesses, occurred in a man with diabetes. A Rhizopus sp grew from the initial nasal biopsy specimens. Successful therapy consisted of correcting metabolic acidosis, using serial computed tomographic (CT) scans to follow the progressive course of brain involvement from cerebritis to encapsulated abscesses, and performing successive biopsies to determine the adequacy of treatment. On 18-month follow-up, the patient had returned to full-time employment with minimal neurologic impairment. With CT scanning and aggressive therapy, rhinocerebral mucormycosis with bilateral brain involvement can be cured.

Antibiotic resistance in anaerobic bacteria: molecular biology and clinical aspects

The patterns of antibiotic susceptibility among anaerobes isolated in the United States during the past 14 years were reviewed. Resistance to the tetracyclines, the penicillins, clindamycin, and other antibiotics has emerged among strains of Bacteroides, Clostridium, and anaerobic cocci. Genetic transfer of antibiotic resistance has been documented in anaerobic environments. Inter- and intrageneric transfer by conjugation and transformation has been described. Plasmids have been identified in anaerobes, and conjugal transfer of antibiotic resistance has been reported. The biochemical mechanisms of antibiotic resistance in anaerobes are similar to those described for aerobes. There are some differences in drug transport and inhibitory actions. Antibiotic resistant anaerobes have been isolated from patients participating in large comparative studies of anaerobic infections involving abdominal, pelvic, and pleuropulmonary sites, but instances in which treatment has failed as a result of resistance have not been found. Reports describing small numbers of patients or individual cases have documented the failure of therapy in clinical and laboratory infections caused by both sensitive or resistant anaerobic bacteria. Patterns of antibiotic susceptibility among clinically important anaerobes need to be monitored periodically in several geographic regions.

Topical polyriboinosinic-polyribocytidylic acid complex in the treatment of recurrent genital herpes

Polyriboinosinic-polyribocytidylic acid complexed with poly-l-lysine and carboxymethylcellulose [poly(ICLC)] is a potent interferon inducer when given parenterally to humans. Topical application in animal models has shown beneficial antiviral and clinical effects. In a randomized, double-blinded, placebo-controlled trial of topical poly(ICLC) in recurrent genital herpes simplex virus infection, five clinical and two virological parameters were followed. Fifty-seven men and women, with 78 recurrences of genital herpes, were stratified by sex. No clinical or antiviral differences between poly(ICLC) and placebo groups in either stratum were found. Further analysis of male subgroups by age and size of lesions showed no changes in the rapidity of healing or viral shedding.

Outbreak of pseudomonas paucimobilis in an intensive care facility

During a two-month period, six patients in an intensive care unit (ICU) were colonized or infected with Pseudomonas paucimobilis, a newly described bacterial species. To our knowledge, the epidemic organism has not been found previously in these units. The bacterium was usually recovered from the sputum of persons receiving ventilatory assistance and represented transient colonization. One patient had a symptomatic urinary tract infection. The outbreak was confined to two of the ICUs. Cultures of respiratory equipment were negative, but P paucimobilis was recovered from the ICU hot water line. Water bottles used for rinsing tracheal suction connecting tubing were found to contain P paucimobilis organisms. This resulted from refilling with tap water. No further cases were found during a 20-month follow-up period, when a uniform tracheal suctioning policy was developed.

Prevention of infection on the oncology unit

Various combinations of immune deficiency, tumor effect, surgery, ionizing radiation, chemotherapy, and neutropenia result in infection-prone states for hospitalized cancer patients. Recognition of nosocomial infection may be difficult, and fever may be the only finding. Pathogens may be exogenously acquired from the contaminated hospital environment. Transmission by contact with hospital personnel is the usual mode of exogenous acquisition of hospital bacteria, and handwashing is the most effective means of prevention. The utility of conventional protective isolation in prevention of exogenous transmission is in question. Inattention to infection control measures by nurses and physicians may result in higher infection rates and more serious types of infections. Endogenous infection by the patient's own bacteria and fungi also occurs in the cancer ward. Autoinfection is "amplified" by the use of cannulae, catheters, and other hospital devices. Meticulous nursing care, particularly in neutropenic persons, is important in reducing the incidence of endogenous spread of microbes. Exogenous and endogenous infections in neutropenic patients are reduced using laminar air flow rooms combined with prophylactic antibiotics. It is still not clear if these expensive measures are effective in prolonging survival of patients with acute leukemia.

Non-traumatic gram-negative bacillary meningitis in the Detroit Medical Center, 1964-1974; (with special mention of cases due to Escherichia coli)

Clinical and autopsy records of eight adults with non-traumatic gram-negative bacillary meningitis who were admitted to the hospitals of the Wayne State University--Detroit Medical Center during the years 1964 to 1974 were reviewed. There were five community-acquired cases, and five patients died. Escherichia coli was the causative enteric bacillus in six cases. Community-acquired infections were due to Esch. coli in four of the patients. Each of the patients with a community-acquired infection was a chronic alcoholic. Esch. coli bronchopneumonias, urinary infections, and bacteremias seeding the meninges were usual. Shunting contaminated portal venous blood through the liver in patients with Laennec's cirrhosis, or bypassing the liver with similar infected blood from a genitourinary source by way of Batson's perivertebral plexus draining into the cerebral dural sinuses may be important in the pathogenesis of these infrequent cases of nontraumatic gram-negative bacillary meningitis. Spontaneous gram-negative bacteremias, peritonitis, bronchopneumonias, and now "meningitis" may be a constellation of special complications of the alcoholic. Mortality among 25 patients with Esch. coli meningitis reported from 1922 to 1974 is approximately 50%, and has not changed appreciably during the antibiotic era. Mortality, however, is significantly higher in nosocomially acquired cases. Early and more recent cases have had bloody, xanthochromic pleocytoses indicative of leptomeningeal arterial and venous vasculitis, and far advanced disease. Since causative/enteric bacilli have been susceptible to antimicrobial agents employed, another mode of antibacterial administration, perhaps utilizing parenteral plus intraventricular dosing, particularly for patients acquiring their infections in the hospital, may be required.