Pathogenesis of infections due to coagulase-negative staphylococci.

Institute of Medical Microbiology, University of Münster Hospital and Clinics, Münster, Germany.
The Lancet Infectious Diseases (Impact Factor: 19.45). 12/2002; 2(11):677-85. DOI: 10.1016/S1473-3099(02)00438-3
Source: PubMed

ABSTRACT As a group, the coagulase-negative staphylococci (CoNS) are among the most frequently isolated bacteria in the clinical microbiology laboratory and are becoming increasingly important, especially as causes of hospital-acquired infections. These bacteria are normal inhabitants of human skin and mucous membranes and, therefore, one of the major challenges of daily diagnostic work is to distinguish clinically significant CoNS from contaminant strains. This overview addresses current knowledge of the pathogenesis of infections due to CoNS and particularly focuses on virulence factors of the species Staphylococcus epidermidis. S epidermidis has been identified as a major cause of nosocomial infections, especially in patients with predisposing factors such as indwelling or implanted foreign polymer bodies. Most important in the pathogenesis of foreign-body-associated infections is the ability of these bacteria to colonise the polymer surface by the formation of a thick, multilayered biofilm. Biofilm formation takes place in two phases. The first phase involves the attachment of the bacteria to polymer surfaces that may be either unmodified or coated with host extracellular matrix proteins. In the second phase, the bacteria proliferate and accumulate into multilayered cell clusters that are embedded in an extracellular material. The bacterial factors involved in both phases of biofilm formation are discussed in this review. In addition, the most important aspects of the pathogenic potential of S saprophyticus, S lugdunensis, and S schleiferi are described, although, compared with S epidermidis, much less is known in these species concerning their virulence factors.

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    ABSTRACT: Background: Staphylococci bacteria cause different diseases, varies from mild skin infections to serious bacteremia. Also they are a major cause of nosocomial and community-acquired infections globally. Staphylococcus aureus and Staphylococcus epidermidis are the two important opportunistic pathogens of the staphylococci that both can cause bacteremia. Objectives: The aim of the present study was to investigate the prevalence and antibiotic resistance pattern of S. aureus and S. epidermidis among blood culture of patients of Ghaem Educational, Research and Treatment Center, Mashhad, Iran, during 6 years (2006 - 2011). Patients and Methods: In this retrospective study, hospital medical records of 28000 patients referred to Ghaem Educational, Research and Treatment Center, Mashhad, Iran, who were suspicious of blood infections during 6 years (2005-2011), were extracted. The patient’s blood culture with staphylococcal growth and their antibiogram results during 2006 - 2011 were collected and studied. Results: Staphylococcus spp. were isolated from 600 (2.14%) out of 28000 blood cultures. Furthermore, 420 (70%), 170 (28.3%) and 10 (1.7%) out of 600 bacterial isolates identified as S. epidermidis, S. aureus and other Staphylococcus spp., respectively. Ampicillin, amoxicillin, cefixime, ceftazidime, penicillin, oxacillin, nalidixic acid and cephepime were the most antibiotics that the isolates were resistant against. Also vancommycin and chloramphenicol were the most effective antibiotics against S. epidermidis and S. aureus, respectively. Conclusions: Prevalence of Staphylococcal bacteremia caused by S. epidermidis is fairly high comparing to S. aureus among patients referred to Ghaem Educational, Research and Treatment Center, Mashhad, Iran. Also the resistance rate of Staphylococcus spp. isolated from blood against commonly used antibiotic is high, but there are some highly sensitive antibiotic against the infection.
  • 01/2010; 4(1):81-82. DOI:10.1093/ndtplus/sfq185
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    ABSTRACT: It is uncertain whether an initial inappropriate empirical antibiotic treatment of coagulase-negative staphylococci (CoNS) bacteremia adversely affects the outcome. A retrospective cohort study of CoNS bacteremia was performed at the Dongguk University Ilsan Hospital during a 3-year period. During the study period, 109 patients with CoNS bacteremia were enrolled. The median age of the patients was 72 years and most (96 %, 105/109) had one or more comorbid diseases. Among the participants, 29 % (32/109) received an appropriate empirical antimicrobial therapy. The 30-day mortality was 24 % (26/109) and CoNS bacteremia-related mortality was 14 % (15/109). There was no difference in the CoNS bacteremia-related mortality between the group with an inappropriate empirical treatment (13 %, 10/77) and that with an appropriate treatment (16 %, 5/32) (p = 0.46). In the multivariate analysis using the Cox regression analysis method, Pitt bacteremia scores [hazard ratio (HR) 1.48; 95 % confidence interval (CI) 1.09-2.01; p = 0.01] and retention of eradicable focus (HR 5.0; 95 % CI 1.39-17.9; p = 0.01) were found to be associated with CoNS bacteremia-related mortality. The results suggest that inappropriate empirical therapy might not necessarily be associated with the 30-day mortality or CoNS bacteremia-related mortality. Conversely, Pitt bacteremia scores and retention of eradicable focus were associated with poor outcomes.
    European Journal of Clinical Microbiology 04/2015; DOI:10.1007/s10096-015-2364-3 · 2.54 Impact Factor


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