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Infecting Organisms (infecting + organism)

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Medical Sciences100%

Selected Abstracts

Dysregulation of monocyte oxidative burst in streptococcal endocarditis

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2001
E. Presterl
Background Streptococcal subacute endocarditis is characterized by low-grade systemic inflammation. Although structural cardiac defects are pivotal, phagocytic cells, i.e. monocytes and neutrophils, are involved in the induction and the course of bacterial endocarditis. Decreased production of reactive oxygen metabolites was described in long-lasting infections. We hypothesized that the oxidative burst of phagocytes induced by the infecting organism is defective in patients with streptococcal endocarditis. Patients and methods The monocytes and neutrophils of 11 patients with streptococcal native valve endocarditis were challenged with the respective pathogens and two control streptococcal strains, and the oxidative burst was determined by fluorescence-activated cell sorter analysis. These experiments were done before any antibiotic therapy was administered, and repeated at least 12 months after recovery. Eight volunteers served as healthy controls. Results The monocyte response to the respective pathogens was decreased in the patient groups compared to the response to the control streptococci. After cure the monocyte response to the pathogens was not different to the response to the control strains. The monocyte response of the healthy volunteers did not show any differences between the patients' pathogens and the control strains. The neutrophil oxidative burst to the pathogens was similar to that to the control streptococci in both patient and the volunteer group. Conclusion The decreased response of patient monocytes to the pathogens may contribute to the low-grade inflammatory response and to the course of streptococcal endocarditis. [source]

Resistant Pathogens in Urinary Tract Infections

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 2002
Lindsay E. Nicolle MD
Antimicrobial susceptibility of bacteria causing urinary tract infection (UTI) has evolved over several decades as antimicrobial exposure has repeatedly been followed by emergence of resistance. Older populations in the community, long-term care facilities, or acute care facilities have an increased prevalence of resistant bacteria isolated from UTI. Resistant isolates are more frequent in long-term care populations than the community. Resistant isolates include common uropathogens, such as Escherichia coli or Proteus mirabilis, and organisms with higher levels of intrinsic resistance, such as Pseudomonas aeruginosa or Providencia stuartii. Isolation of resistant organisms is consistently associated with prior antimicrobial exposure and higher functional impairment. The increased likelihood of resistant bacteria makes it essential that a urine specimen for culture and susceptibility testing be obtained before instituting antimicrobial therapy. Therapy for the individual patient must be balanced with the possibility that antimicrobial use will promote further resistance. Antimicrobial therapy should be avoided unless there is a clear clinical indication. In particular, asymptomatic bacteriuria should not be treated with antimicrobials. Where symptoms are mild or equivocal, urine culture results should be obtained before initiating therapy. This permits selection of specific therapy for the infecting organism and avoids empiric, usually broad-spectrum, therapy. Where empirical therapy is necessary, prior infecting organisms should be isolated, and recent antimicrobial therapy, as well as regional or facility susceptibility patterns, should be considered in antimicrobial choice. Where empirical therapy is used, it should be reassessed 48 to 72 hours after initiation, once pretherapy cultures are available. [source]

Prevention and management of infections in patients without a spleen

CLINICAL MICROBIOLOGY AND INFECTION, Issue 12 2001
R. N. Davidson
Patients who lack a functioning spleen become vulnerable to sepsis caused by bacteria and, occasionally, protozoa. The risk is higher in children and in those who have had immunosuppressive treatment, and the risk remains lifelong. Overwhelming post-splenectomy infection (OPSI) occurs at an estimated incidence of 0.23,0.42% per year, with a lifetime risk of 5%. Episodes of OPSI are emergencies, requiring immediate parental antibiotics and intensive care; intravenous immunoglobulins may be useful. OPSI carries a mortality of 38,69%. Streptococcus pneumoniae is the commonest infecting organism, accounting for 50,90% of isolates from blood cultures in reported series; it is particularly common in children with sickle cell disease. Less commonly, the infecting organisms are other bacteria, Babesia or Ehrlichia. OPSI may be, to some extent, preventable by several interventions. These are surgical conservation of the spleen; immunization against S. pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis; prophylactic antibiotics; stand-by antibiotics; patient information sheets; and a medical alert bracelet. Asplenic patients living in malaria-endemic areas require optimal prophylaxis. The initial step in prevention of OPSI is the creation of an asplenia register, as many patients are not covered by these simple measures. [source]

Tinea faciei, an often deceptive facial eruption

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 6 2004
Richie L. Lin MD
Tinea faciei is a relatively uncommon superficial dermatophyte infection limited to the glabrous skin of the face. It is usually seen in pediatric patients. This fungus can be found worldwide, but has a predilection for tropical humid climates. Although the infecting organisms and treatments are the same as for other superficial fungal infections, it is frequently misdiagnosed clinically and histologically. [source]

Resistant Pathogens in Urinary Tract Infections

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 2002
Lindsay E. Nicolle MD
Antimicrobial susceptibility of bacteria causing urinary tract infection (UTI) has evolved over several decades as antimicrobial exposure has repeatedly been followed by emergence of resistance. Older populations in the community, long-term care facilities, or acute care facilities have an increased prevalence of resistant bacteria isolated from UTI. Resistant isolates are more frequent in long-term care populations than the community. Resistant isolates include common uropathogens, such as Escherichia coli or Proteus mirabilis, and organisms with higher levels of intrinsic resistance, such as Pseudomonas aeruginosa or Providencia stuartii. Isolation of resistant organisms is consistently associated with prior antimicrobial exposure and higher functional impairment. The increased likelihood of resistant bacteria makes it essential that a urine specimen for culture and susceptibility testing be obtained before instituting antimicrobial therapy. Therapy for the individual patient must be balanced with the possibility that antimicrobial use will promote further resistance. Antimicrobial therapy should be avoided unless there is a clear clinical indication. In particular, asymptomatic bacteriuria should not be treated with antimicrobials. Where symptoms are mild or equivocal, urine culture results should be obtained before initiating therapy. This permits selection of specific therapy for the infecting organism and avoids empiric, usually broad-spectrum, therapy. Where empirical therapy is necessary, prior infecting organisms should be isolated, and recent antimicrobial therapy, as well as regional or facility susceptibility patterns, should be considered in antimicrobial choice. Where empirical therapy is used, it should be reassessed 48 to 72 hours after initiation, once pretherapy cultures are available. [source]

The Prevotella intermedia group organisms in young children and their mothers as related to maternal periodontal status

JOURNAL OF PERIODONTAL RESEARCH, Issue 6 2000
Eija Könönen
Currently, the Prevotella intermedia group includes three biochemically and phylogenetically related species: Prevotella intermedia, Prevotella nigrescens, and the newly described Prevotella pallens. The two first-named species are mentioned with varying emphasis in connection with periodontal diseases, while such a connection of P. pallens is not known. Mothers serve as a plausible source of bacteria to their children, and conceivably, a mother with periodontitis as a recurrent reservoir of periodontally infecting organisms. In the present study, 23 mothers and their young children were examined for the presence of the P. intermedia group organisms in relation to maternal periodontal status (I: periodontal health, II: initial periodontitis, and III: advanced periodontitis). Species differentiation was based on established biochemical methods, electrophoretic mobility patterns, SDS-PAGE, and DNA hybridization. P. intermedia was not recovered from children but nearly exclusively from mothers in group III, thus confirming its association with periodontitis. P. nigrescens and P. pallens were frequently found in mothers and children. To determine bacterial transmission between a mother and her child, 72 isolates from 13 mother,child pairs were analyzed by arbitrarily primed PCR (AP-PCR). Similar AP-PCR types of P. nigrescens and/or P. pallens were recovered from 3/4 pairs in group I, 2/5 pairs in group II, and none in group III. Our results indicate that different species within the P. intermedia group have a different colonization pattern in childhood and that the periodontal status reflects qualitatively their presence in maternal saliva. Intra-familial transmission of P. nigrescens and P. pallens can occur in early childhood, however similar AP-PCR types were most obvious within periodontally healthy mother,child pairs. [source]

Prevention and management of infections in patients without a spleen

CLINICAL MICROBIOLOGY AND INFECTION, Issue 12 2001
R. N. Davidson
Patients who lack a functioning spleen become vulnerable to sepsis caused by bacteria and, occasionally, protozoa. The risk is higher in children and in those who have had immunosuppressive treatment, and the risk remains lifelong. Overwhelming post-splenectomy infection (OPSI) occurs at an estimated incidence of 0.23,0.42% per year, with a lifetime risk of 5%. Episodes of OPSI are emergencies, requiring immediate parental antibiotics and intensive care; intravenous immunoglobulins may be useful. OPSI carries a mortality of 38,69%. Streptococcus pneumoniae is the commonest infecting organism, accounting for 50,90% of isolates from blood cultures in reported series; it is particularly common in children with sickle cell disease. Less commonly, the infecting organisms are other bacteria, Babesia or Ehrlichia. OPSI may be, to some extent, preventable by several interventions. These are surgical conservation of the spleen; immunization against S. pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis; prophylactic antibiotics; stand-by antibiotics; patient information sheets; and a medical alert bracelet. Asplenic patients living in malaria-endemic areas require optimal prophylaxis. The initial step in prevention of OPSI is the creation of an asplenia register, as many patients are not covered by these simple measures. [source]