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Query: UMLS:C0004623 (bacterial infection)
 15,226 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We prospectively studied features of pyogenic bacterial pneumonia in 263 consecutive human immunodeficiency virus-infected inpatients over a 6-month study period. Risk factors for bacterial pneumonia were examined by a case-control study that included 33 cases who presented with at least one episode of bacterial pneumonia and 80 controls without bacterial pneumonia. The estimated cumulative incidence of bacterial pneumonia per year was 12.5 cases per 100 inpatients (95% confidence interval [CI], 8.8-17.2). The 38 episodes of bacterial pneumonia that occurred in the 33 inpatients were mainly unilateral, but 32 episodes were patchy lobar or diffuse infiltrates. Microbiological etiologies were obtained in 33 of the 38 episodes of bacterial pneumonia. Thirty-seven pathogens were identified, including Streptococcus pneumoniae (16, of which 12 had a decreased susceptibility to penicillin), Haemophilus influenzae (6), and Pseudomonas aeruginosa (6). The risk factors for bacterial pneumonia that were identified after logistic regression included prior sinusitis within 1 month before admission (odds ratio [OR], 3.2; 95% CI, 1.1-9.1) and prior bacterial infection of the lower respiratory tract within 6 months before admission (OR, 3.1; 95% CI, 1.1-8.3).
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PMID:Pyogenic bacterial pneumonia in human immunodeficiency virus-infected inpatients: a clinical, radiological, microbiological, and epidemiological study. 1006 68

Periapical inflammatory responses occur as a consequence of bacterial infection of the dental pulp, as a result of caries, trauma, or iatrogenic insult. Periapical inflammation stimulates the formation of granulomas and cysts, with the destruction of bone. These inflammatory responses are complex and consist of diverse elements. Immediate-type responses--including vasodilatation, increased vascular permeability, and leukocyte extravasation--are mediated by endogenous mediators, including prostanoids, kinins, and neuropeptides. Non-specific immune responses--including polymorphonuclear leukocyte and monocyte migration and activation, and cytokine production--are elicited in response to bacteria and their products. Interleukin-1 and prostaglandins in particular have been implicated as central mediators of periapical bone resorption. Chronic periapical inflammation further involves specific T- and B-cell-mediated anti-bacterial responses, and activates a network of regulatory cytokines which are produced by Th1- and Th2-type T-lymphocytes. Various naturally occurring and genetically engineered models of immunodeficiency are beginning to help elucidate those components of the immune system which protect the pulpal/periapical complex. Both specific and non-specific responses interface with and are regulated by the neural system. The modulation of these responses by immune response modifies, cytokine antagonists, and other novel therapeutic agents is discussed. As an experimental model, periapical inflammation has many advantages which permit it to be used in studies of microbial ecology and pathogenesis, host response, neuroimmunology, and bone resorption and regeneration.
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PMID:Periapical inflammatory responses and their modulation. 982 24

Neutropenia and impairment of neutrophil function are commonly observed in patients with human immunodeficiency virus (HIV) infections. The HIV regulatory protein Tat is known to exert immunosuppressive effects. Alcohol is known also to be an immunosuppressive factor, and as alcohol abuse is common among HIV infected hosts, both factors may interact in an additive or synergistic fashion to further impair the host defenses of these patients. In order to test this possibility, endotoxin-induced neutrophil beta2-integrins CD11b and CD18 expression, phagocytosis, and hydrogen peroxide generation were examined in normal and HIV-1 Tat-transgenic mice in the absence and presence of ethanol intoxication. Acute ethanol intoxication was induced in mice (body weight of 25+/-1 g) by an intraperitoneal (ip) injection of ethanol (3 g/kg, 20% in normal saline). Thirty min later, the animals were given an ip injection of endotoxin (20 microg in 0.2 ml of saline/mouse). Vehicle-treated controls received an ip injection of saline without ethanol or endotoxin. Two hr after endotoxin administration, the animals were killed to determine neutrophil functions with flow cytometry. The baseline expression of CD11b and CD18 was similar in normal nontransgenic and Tat-transgenic mice. Endotoxin administration significantly up-regulated CD11b and CD18 expression in normal mice. This up-regulation was suppressed in Tat-transgenic mice. Ethanol intoxication inhibited endotoxin-induced CD11b and CD18 expression in normal mice and totally abolished endotoxin-induced CD11b and CD18 expression in Tat-transgenic mice. Neutrophil phagocytic activity in normal and Tat-transgenic mice was similar. Ethanol intoxication produced a similar inhibition of phagocytosis in both study groups. Endotoxin suppressed phagocytosis in normal mice, and this suppression was more pronounced in Tat-transgenic mice. Spontaneous and phorbol myristate acetate (PMA)-stimulated hydrogen peroxide generation by circulating neutrophils (PMNs) were similar in normal and Tat-transgenic mice. Neither ethanol nor endotoxin affected hydrogen peroxide generation by PMNs. These data show that both Tat and alcohol significantly impair PMN function, and this may be a mechanism leading to the increased susceptibility of the HIV-infected host to bacterial infection.
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PMID:The human immunodeficiency virus type I Tat protein potentiates ethanol-induced neutrophil functional impairment in transgenic mice. 988 49

To study the influence of human immunodeficiency virus (HIV) infection on phagocytosis of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by polymorphonuclear neutrophils (PMN) from HIV-infected patients in vitro. PMN were isolated from the blood of 25 HIV-infected patients (group 1: CD subset4 </= 250/microL: 14 patients, group 2: CD subset4 >250/microL: 11 patients ) by Percoll density gradient and incubated with E. coli and S. aureus. Subculture technique was used to determine PMN function at 0, 0.5, 1, 2, 4, 6, and 24 hours. Controls were run with PMN from healthy volunteers. Phagocytosis of E.coli and S.aureus by PMN of HIV-infected patients was significantly lower in group 1 (p <0.05). Reduced phagocytosis of E. coli and S. aureus was found in HIV-infected patients with low CD subset4-cell counts. Our findings may contribute to increased susceptibility to bacterial infection in HIV-infected patients with low CD subset4-cell counts.
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PMID:Phagocytosis of Escherichia coli and Staphylococcus aureus by neutrophils of human immunodeficiency virus-infected patients. 988 73

Arterial aneurysms have only recently been associated with the human immunodeficiency virus (HIV). The clinical and pathological features of 10 HIV-positive patients with arterial aneurysms were retrospectively evaluated. These aneurysms were unusual in that they affected young black patients, occurred in atypical sites, and tended toward multiplicity. Surgery was performed in eight patients. Acute and chronic inflammatory changes were revealed by means of histologic examination of the aneurysm walls, with occlusion of the vasa vasora by inflammatory infiltrate or edema being a prominent feature. Culture of the aneurysm wall or thrombus yielded positive results in two patients. The association between HIV and aneurysms may be coincidental, caused by direct viral action or by bacterial infection resulting from immunosuppression. Implications for therapy are discussed, and the need for further study is highlighted.
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PMID:Arterial aneurysms in patients infected with human immunodeficiency virus: a distinct clinicopathology entity? 1019 86

Bacterial infections are a major cause of morbidity and mortality in persons with human immunodeficiency virus (HIV) infection, particularly women. We performed a cross-sectional analysis of a history of bacterial infections among 1,310 women with or at risk for HIV infection. HIV-seropositive women were significantly more likely than seronegative women to report recent and lifetime histories of bacterial infection, even after history of injection drug use since 1977 was adjusted for; this included recent pneumonia (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.5-6.6), sinusitis (OR, 1.4; 95% CI, 1.0-2.0), and urinary tract infection (OR, 1.5; 95% CI, 1.1-2.1). Compared with HIV-negative women, women with CD4 cell counts of <200 were about eight times more likely to report recent pneumonia (OR, 7.8; 95% CI, 3.4-17.7); those with CD4 cell counts of 200-500 were almost three times more likely to do so (OR, 2.6; CI, 1.2-5.7). Logistic regression analysis revealed that only CD4 cell category and a recent history of smoking had a significant relationship to self-reported pneumonia.
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PMID:Self-reported bacterial infections among women with or at risk for human immunodeficiency virus infection. 1053 Apr 55

The authors report a case and treatment of multiple brain abscesses located in the cerebrum and cerebellum combined with subdural empyema. In conjunction with the case report, the authors review the literature on the pathogenesis of brain abscesses and discuss therapeutic strategies concerning the topic. In the case presented, the primary infection persisted in the lung causing subclinical bronchitis. The hemoculture showed evidence of Streptococcus mitis infection. Although the etiological role of this bacterium in meningitis is known, it rarely causes bacterial meningitis without underlying predisposing factors. In their case, the patient was free of the most common predisposing factors such as congenital heart disease or immunodeficiency. Following the 2 month period of latency, a rapid onset of the symptoms of intracranial inflammation could be observed: fever, headache, meningeal symptoms, focal neurological symptoms and coma. They were not able to identify any bacteria in the cerebrospinal fluid; the Streptocossus mitis could be cultivated only from the haemoculture. The cytological analysis of the cerebrospinal fluid showed typical signs of bacterial infection and the cranial Computed Tomography revealed multiple cerebral abscesses. Neurosurgical intervention was not recommended because of the number, localization and size of the focal lesions. The therapy consisted of intravenous administration of 24 x 10(6) IU/die Penicillin and 4 g/die ceftriaxon. For supportive therapy, Mannitol B, 3 mg/die clonazepam and 300 mg/die phenytoin were administered. Corticosteroids were not used during the course of therapy. Two years later the 55 year old female is symptom free and doing well.
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PMID:[Non-invasive management of multiple brain abscesses. Case report and review of the literature]. 1053 93

The number of people infected with human immunodeficiency virus (HIV) is gradually increasing in Japan, and the morbidity rate from tuberculosis in the Japanese people is high. Accordingly, the number of cases with both infections is considered to increase in the future. Our hospital has already encountered 22 cases of HIV associated tuberculosis. HIV infects mainly CD4-positive cells. The extreme decrease in the cell count results in serious cellular immunological disorder. CD4-positive cell disorder induces disorders of B lymphocytes, cytotoxic T cells, natural killer cells, and macrophage functions. These destructive conditions show the state of immunodeficiency including macrophage that are most important for defense of acid-fast bacterial infection. Migration and activation of macrophages with cytokines derived from T cells are impaired to induce the following phenomena: hypoplasia of granuloma, failure of tubercle bacillus sppression, the spread to regional lymph nodes (hilar or mediastinal lymph nodes), and hematogenous dissemination. On this occasion, caseous necrosis and cavitation are unlikely to occur, and false-negative tuberculin reaction is often observed. The incidence of severe cases, which include miliary tuberculosis, tuberculous meningitis, etc., and extrapulmonary tuberculosis, are high among acquired immunodeficiency syndrome (AIDS)-associated tuberculosis cases. HIV-infected tuberculosis cases are generally regarded as endogenous exacerbation, but they include primary infection and reinfection as well. Even during the treatment for drug-sensitive strains particularly, some cases may have reinfection with multidrug-resistant bacteria, suggesting that caution should be taken against this point. Conversely, the association of tuberculosis is a factor for the poor prognosis of HIV infection, since it facilitates the development of HIV infection. If the bacteria belong to a drug-sensitive strain, the infection with them responds well to antituberculous drugs, the same as in tuberculosis cases without HIV infection, showing a favorable prognosis. However, the mortality rate of infection with multidrug-resistant tuberculosis is extremely high.
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PMID:[Factors for the onset of and the exacerbation of tuberculosis. 5. The infection and prognosis of tuberculosis among patients with immunodeficiency, especially HIV-infected patients]. 1056 37

Neutropenia frequently complicates infection due to human immunodeficiency virus (HIV). The etiology of neutropenia in this setting includes bone marrow infection or infiltration, myelosuppressive therapies, the presence of antibodies to HIV, and accelerated apoptosis. Protection against microbial invaders by neutrophils is further compromised by impaired chemotaxis and phagocytosis, production of toxic oxygen species, and expression of cellular adhesion molecules. Neutropenia is a significant risk factor for bacterial infection in HIV-infected patients. Endogenous cytokines, such as granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor, regulate neutrophil count and function. Treatment with recombinant human methionyl G-CSF (filgrastim) has lessened neutropenia in patients with HIV infection. Clinical trials have shown that the incidence of bacterial infections and the number of consequent days of hospitalization for HIV-infected patients receiving filgrastim therapy are lower. Filgrastim treatment also allows administration of larger doses of myelosuppressive agents.
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PMID:Neutropenia, neutrophil dysfunction, and bacterial infection in patients with human immunodeficiency virus disease: the role of granulocyte colony-stimulating factor. 1067 24

Mycobacterium avium is the most frequent cause of disseminated bacterial infection in patients with human immunodeficiency virus type 1 infection and in rhesus macaques with simian immunodeficiency virus (SIV) infection. This animal model of AIDS was used to test the hypothesis that this frequent association is the result of reciprocal enhancement of replication of both microorganisms. The replication of M. avium and SIV was analyzed in lymphatic tissues obtained from rhesus macaques experimentally inoculated with SIVmac who developed or remained free of overt M. avium infection. In situ hybridization, quantitative image analysis, and staining of M. avium and of macrophages were used to assess the effects of coinfection on the replication of SIV and M. avium in vivo. There was no correlation between virus load and M. avium load in coinfected lymph nodes, and, with one exception, there was no evidence that M. avium coinfection of macrophages increased SIV replication.
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PMID:Quantitative image analysis of simian immunodeficiency virus replication in macrophages coinfected with Mycobacterium avium complex. 1072 May 6


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