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

Beta-lactam antibiotics share the structural feature of a beta-lactam ring. This feature is responsible for inhibition of bacterial cell wall synthesis. The target molecules are peptidoglycan cross-linking enzymes (e.g. transpeptidases and carboxypeptidases) which can bind beta-lactam antibiotics (penicillin binding proteins, PBP). Bacterial cell death is initiated by beta-lactam antibiotic-triggered release of autolytic enzymes. In contrast to gram-positive bacteria (absence of an outer membrane) the antibiotic has to penetrate through porins of the outer membrane of gram-negative bacteria before touching PBP's. Bacterial resistance to beta-lactam antibiotics includes modification of porins (permeability barrier) and of targets (low affinity of PBP's for the drug), production of inactivating enzymes (beta-lactamases) and inhibition of release of autolytic enzymes. Moreover, bacteria have developed sophisticated genetic mechanisms to adapt to treatments with novel beta-lactam antibiotics. To allow successful antibiotic treatment of bacterial infection in the future, knowledge about antibiotic resistance mechanisms is required.
Infection 1993
PMID:[Mechanisms of resistance to beta-lactam antibiotics]. 831 92

We evaluated the efficacy and safety of a new oral fluoroquinolone, ofloxacin (200 mg twice daily), as antibacterial prophylaxis after BMT in a non-comparative prospective study of patients nursed in either LAF plastic isolators or HEPA filtered single rooms. Of the 101 evaluable patients who were neutropenic (< 500 x 10(6)/l) for a median duration of 20 days, 92 (91%) had febrile episodes of varying length and causes. Infections were documented in 34 patients, of whom 14 had proven bacterial infection (13 with bacteremia and one with pneumonia). Mortality rate within 6 weeks after transplant was 6%. Only one patient died from bacterial infection. Univariate analysis using an array of potentially prognostic factors including the type of isolation was not helpful in identifying significant variables for predicting the development of documented infection. Tolerance was excellent. Oral ofloxacin was associated with a relatively low incidence of documented bacterial infection and related mortality, although it did not obviate the need for frequent empiric antimicrobial therapy due to a high incidence of febrile episodes.
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PMID:Single-drug oral antibacterial prophylaxis with ofloxacin in BMT recipients. 837 36

Infections caused by Mycobacterium avium, the most common form of diseminated bacterial disease in AIDS patients, are difficult to treat because of their resistance to many antimycobacterial drugs. The results of the present study show that recombinant migration inhibitory factor, a 12-kDa molecule recently isolated by COS-1 cell expression screening of cDNA from a human T-cell hybridoma, has potent inhibitory activity on the growth of a panel of clinical isolates of M. avium within both bone-marrow-derived murine macrophages and cultured human blood monocytes. These cells cultured in recombinant migration inhibitory factor exhibit various signs of activation, including cell division, morphological changes such as evidence of substantial phagolysosomal fusion, and enhanced secretion of tumor necrosis factor.
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PMID:Inhibition of growth of Mycobacterium avium in murine and human mononuclear phagocytes by migration inhibitory factor. 816 87

Infection and refractoriness to platelet transfusion, as complications in hematopoietic malignancy therapy, were investigated. The Hanshin Study Group of Hematopoietic Disorders and Infection treated with 3,346 cases of bacterial infection (7.8% sepsis, 71% sepsis suspected, 13.7% respiratory infection) during the past 13 years. A total of 688 strains were detected as causative organisms, 59.2% being gram-negative bacilli and 40.3% gram-positive bacteria. Comparison of the detection rates obtained 10 years ago and those obtained in the last three years showed a decrease from 73.8% to 46.8% for gram-negative bacilli and an increase from 25.1% to 53.2% for gram-positive bacteria. Twenty-eight antibiotics administered singly and nine combinations of two drugs administered concomitantly were assessed. Efficacy rates were 43.9% to 67.2% for single-drug administration and 35.2% to 64.2% for concomitant administration. Notably, some combinations were less effective than single-drug administration. Of 153 cases of fungal infection seen in the last three years, 80% were caused by the genus Candida. Two antifungal drugs were used, with efficacy rates ranging from 45.5% to 70.0%. In 150 patients undergoing frequent transfusion, anti-HLA alloantibody was measured. The positive rate was 32.9%. In 76 subjects receiving leukocyte-depleted platelet transfusion using a polyester filter, a decreased alloantibody positive rate of 17.1% was obtained.
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PMID:[Complications and management of hematopoietic malignancy therapy]. 847 74

The incidence of oral alpha-streptococcus with inhibitory activity against group A streptococcus, as a defense mechanism against bacterial infection in the oral cavity, was investigated in pediatric individuals with tonsillitis. Infection by group A streptococcus appeared to be common in children, because the detection rate of inhibitory alpha-streptococcus in healthy children as well as pediatric patients with tonsillitis was lower than in adults and elderly patients. In particular, the detection rate of these strains was predominantly low in patients with beta-streptococcus. Among pediatric patients scheduled for tonsillectomy, the detection rate of inhibitory alpha-streptococcus was low preoperatively. However, the rate was markedly increased after surgery. The high postoperative detection rate of these strains reflected the decreased incidence of group A streptococcal infection. The results of this investigation of bacterial interference between oral alpha-streptococcus and group A streptococcus suggested that surgical treatment is a more effective approach for improving the oral bacterial flora in children with recurrent tonsillitis.
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PMID:Investigation of oral alpha-streptococcus showing inhibitory activity against pathogens in children with tonsillitis. 855 81

The Fc gammaR receptors for IgG, Fc gammaRI, Fc gammaRII and Fc gammaRIII were measured on neutrophils and monocytes from 36 patients suspected of systemic infection. These results were compared with 30 blood donor controls to assess the level of expression as an early indicator of bacterial infection. Fc gammaRI expression on neutrophils was found to be significantly increased from patients with systemic or localised infections, when compared to non-infected patient group, i.e., patients with no cultural evidence of bacterial infections, (p=0.02, p=0.04) or normal controls (p<0.0001, p=0.0005). Fc gammaRI expression on monocytes was also significantly increased in both of the infected groups compared to normal controls (p<0.0001, p=0.001); however, no significant difference could be seen when compared with the non-infected patients. Fc gammaRIII was found to be significantly increased on a subset of monocytes in patients with systemic or localised infections compared to the non-infected group (p=0.009, p=0.006) and compared to the normal controls (p=0.009, p=0.003). Infections caused by gram-negative bacilli induced a higher Fc gammaR response than infection with either streptococci or staphylococci. These data suggest that the measurement of Fc gammaRI on neutrophils and Fc gammaRIII on monocytes may be a useful rapid indicator of bacterial infection.
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PMID:Increased expression of Fc gamma receptors on neutrophils and monocytes may reflect ongoing bacterial infection. 864 75

Myxoma virus is a pathogenic poxvirus that induces a lethal myxomatosis disease profile in European rabbits, which is characterized by fulminating lesions at the primary site of inoculation, rapid dissemination to secondary internal organs and peripheral external sites, and supervening gram-negative bacterial infection. Here we describe the role of a novel myxoma virus protein encoded by the M-T5 open reading frame during pathogenesis. The myxoma virus M-T5 protein possesses no significant sequence homology to nonviral proteins but is a member of a larger poxviral superfamily designated host range proteins. An M-T5- mutant virus was constructed by disruption of both copies of the M-T5 gene followed by insertion of the selectable marker p7.5Ecogpt. Although the M-T5- deletion mutant replicated with wild-type kinetics in rabbit fibroblasts, infection of a rabbit CD4+ T-cell line (RL5) with the myxoma virus M-T5- mutant virus resulted in the rapid and complete cessation of both host and viral protein synthesis, accompanied by the manifestation of all the classical features of programmed cell death. Infection of primary rabbit peripheral mononuclear cells with the myxoma virus M-T5-mutant virus resulted in the apoptotic death of nonadherent lymphocytes but not adherent monocytes. Within the European rabbit, disruption of the M-T5 open reading frame caused a dramatic attenuation of the rapidly lethal myxomatosis infection, and none of the infected rabbits displayed any of the characteristic features of myxomatosis. The two most significant histological observations in rabbits infected with the M-T5-mutant virus were (i) the lack of progression of the infection past the primary site of inoculation, coupled with the establishment of a rapid and effective inflammatory reaction, and (ii) the inability of the virus to initiate a cellular reaction within secondary immune organs. We conclude that M-T5 functions as a critical virulence factor by allowing productive infection of immune cells such as peripheral lymphocytes, thus facilitating virus dissemination to secondary tissue sites via the lymphatic channels.
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PMID:Disruption of M-T5, a novel myxoma virus gene member of poxvirus host range superfamily, results in dramatic attenuation of myxomatosis in infected European rabbits. 867 63

Infections in immunocompromised patients with cancer are common and the primary risk factor is neutropenia, usually induced by chemotherapeutic agents. The spectrum of bacterial infection is shifting from gram-negative to gram-positive. The array of fungal infections in cancer patients is expanding to include organisms previously unknown as invasive human pathogens. New species are being defined to explain extant pathologies, and free living algae are now emerging as pathogens in immunocompromised patients. Physicians must remain alert to these emerging pathogens and to the need to evaluate optimal treatments for the usual and unusual infections in neutropenic and other compromised patients with cancer and allied diseases.
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PMID:New and unusual infections in neutropenic patients. 874 54

Infection is usually considered the main cause of acute exacerbation in chronic obstructive pulmonary disease (COPD). However, uncertainty persists concerning the exact role of bacterial and viral infection in this setting because of the confusing and conflicting data on the role of tracheobronchial microflora and the usefulness of antibiotics in treating this disease. Most COPD patients have evidence of lower respiratory tract chronic bacterial colonization during remission periods as well as during acute exacerbations. This is evidenced by using microbiological analysis of secretions, which reflect all the respiratory tract (sputum), the lower respiratory tract (transtracheal aspiration), or the distal respiratory tract (protected specimen brush). Potentially pathogenic organisms can be recovered from the respiratory tract secretions of virtually all patients with COPD at some time during the course of their disease. Absence of difference in isolation of potentially pathogenic organisms between remission periods and acute exacerbations suggests that bacterial infection is probably not the predominant cause of acute exacerbations in COPD. In contrast, data indicate that the association between viral infections and acute exacerbations is clearer than that with bacteria, affecting probably more than 20% of cases. The role of antibiotic therapy in acute exacerbations of COPD remains controversial. (1) Clearly, antibiotic therapy is urgently required in COPD patients with pneumonia. (2) Review of the conflicting results of studies evaluating the role of antibiotic therapy for preventing acute exacerbations suggests that there is no clear-cut rationale for prophylactic treatment of infection for all patients with COPD; it seems, however, that such treatment may be of some use in highly selected patients, such as those with many exacerbations in the winter. (3) Similarly, data are conflicting concerning the curative use of antibiotic therapy, with some studies suggesting acceleration of recovery, prevention of acute deterioration, and longer period of freedom from recurrent exacerbations; conversely many patients recover from exacerbations without resorting to an antibiotic. Unfortunately, no clear data identify patients who could benefit from antibiotic treatment, probably justifying most clinicians' choice to treat acute exacerbations as infectious events.
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PMID:Severe exacerbations of COPD patients: the role of pulmonary infections. 877 80

Infection with Mycobacterium avium complex (MAC) may cause a serious disseminated bacterial infection in up to 40% of patients with advanced HIV infection. Disseminated MAC has a negative impact on quality of life and contributes significantly to morbidity and mortality. Prompt diagnosis and aggressive treatment can diminish those effects. Disseminated disease can be prevented in many patients with the use of rifabutin prophylaxis. Nurses play an important role in evaluating symptoms and educating patients about the prevention and treatment of disseminated MAC.
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PMID:Mycobacterium avium complex infection in AIDS: clinical features, treatment, and prevention. 878 15


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