Posts filed under ‘Infecciones cardio-vasculares’

Should Acute Q-Fever Patients be Screened for Valvulopathy to Prevent Endocarditis?

Clinical Infectious Diseases August 1, 2018 V.67 N.3 P.360-366

Marit M A de Lange; Laura E V Gijsen; Cornelia C H Wielders; Wim van der Hoek; Arko Scheepmaker

We found no difference in occurrence of chronic Q-fever between patients with or without a newly detected valvulopathy at time of acute Q-fever diagnosis. Thus, universal screening is not justified and would lead to unnecessary and undesirable long-term antibiotic use.




November 4, 2018 at 8:29 am

Understanding the Mechanism of Bacterial Biofilms Resistance to Antimicrobial Agents.

Open Microbiol J. 2017 Apr 28;11:53-62.

Singh S1, Singh SK2, Chowdhury I3, Singh R2.

1 Department of Kriya Sharir, Institute of Medical Sciences, Banaras Hindu University, Varanasi- 221 005 UP India.

2 Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA.

3 Department of Obstetrics and Gynecology; Morehouse School of Medicine, Atlanta, GA, USA.


A biofilm is a group of microorganisms, that causes health problems for the patients with indwelling medical devices via attachment of cells to the surface matrix. It increases the resistance of a microorganism for antimicrobial agents and developed the human infection. Current strategies are removed or prevent the microbial colonies from the medical devices, which are attached to the surfaces. This will improve the clinical outcomes in favor of the patients suffering from serious infectious diseases. Moreover, the identification and inhibition of genes, which have the major role in biofilm formation, could be the effective approach for health care systems. In a current review article, we are highlighting the biofilm matrix and molecular mechanism of antimicrobial resistance in bacterial biofilms.



October 14, 2018 at 10:44 am

Biofilms: survival mechanisms of clinically relevant microorganisms.

Clinical Microbiology Reviews April 2002 V.15 N.2 P.167-93.

Donlan RM1, Costerton JW.

1 Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.


Though biofilms were first described by Antonie van Leeuwenhoek, the theory describing the biofilm process was not developed until 1978. We now understand that biofilms are universal, occurring in aquatic and industrial water systems as well as a large number of environments and medical devices relevant for public health. Using tools such as the scanning electron microscope and, more recently, the confocal laser scanning microscope, biofilm researchers now understand that biofilms are not unstructured, homogeneous deposits of cells and accumulated slime, but complex communities of surface-associated cells enclosed in a polymer matrix containing open water channels. Further studies have shown that the biofilm phenotype can be described in terms of the genes expressed by biofilm-associated cells. Microorganisms growing in a biofilm are highly resistant to antimicrobial agents by one or more mechanisms. Biofilm-associated microorganisms have been shown to be associated with several human diseases, such as native valve endocarditis and cystic fibrosis, and to colonize a wide variety of medical devices. Though epidemiologic evidence points to biofilms as a source of several infectious diseases, the exact mechanisms by which biofilm-associated microorganisms elicit disease are poorly understood. Detachment of cells or cell aggregates, production of endotoxin, increased resistance to the host immune system, and provision of a niche for the generation of resistant organisms are all biofilm processes which could initiate the disease process. Effective strategies to prevent or control biofilms on medical devices must take into consideration the unique and tenacious nature of biofilms. Current intervention strategies are designed to prevent initial device colonization, minimize microbial cell attachment to the device, penetrate the biofilm matrix and kill the associated cells, or remove the device from the patient. In the future, treatments may be based on inhibition of genes involved in cell attachment and biofilm formation.


October 14, 2018 at 10:41 am

Biofilm formation: a clinically relevant microbiological process.

Clinical Infectious Disseases October 15, 2001 V.33 N.8 P.1387-92.

Donlan RM1.

1 Biofilm Laboratory, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.


Microorganisms universally attach to surfaces and produce extracellular polysaccharides, resulting in the formation of a biofilm. Biofilms pose a serious problem for public health because of the increased resistance of biofilm-associated organisms to antimicrobial agents and the potential for these organisms to cause infections in patients with indwelling medical devices. An appreciation of the role of biofilms in infection should enhance the clinical decision-making process.




October 14, 2018 at 10:39 am

Bacterial biofilms: resistance to antimicrobial agents.

Journal of Antimicrobial & Chemotherapy June 1996 V.37 N.6 P.1047-50.

Gander S1.

1 Department of Microbiology, Nottingham City Hospital, UK.



October 14, 2018 at 10:36 am

Risk of Infective Endocarditis After Invasive Dental Treatments: A Case-Only Study.

Circulation April 19, 2018 V.138 N.4 P.356-363   

Chen TT1, Yeh YC2, Chien KL3, Lai MS1, Tu YK4.



Invasive dental treatments (IDTs) can yield temporary bacteremia and has therefore been considered a potential risk factor of infective endocarditis (IE). It is hypothesized that, through the trauma caused by IDTs, bacteria gain entry to the bloodstream and may attach to abnormal heart valves or damaged heart tissue, giving rise to IE. However, the association between IDTs and IE remains controversial. The aim of this study is to estimate the association between IDTs and IE.


The data in this study were obtained from the Health Insurance Database in Taiwan. We selected two case-only study designs, case-crossover and self-controlled case series, to analyze the data. The advantage of these methods is that confounding factors which do not vary with time are adjusted for implicitly. In the case-crossover design, conditional logistic regression model with exposure to IDTs was used to estimate the risks of IE following an IDT with 4, 8, 12, and 16 weeks delay, respectively. In the self-controlled case series design, conditional Poisson regression model was used to estimate the risk of IE for the risk periods of 1-4, 5-8, 9-12, and 13-16 weeks following an IDT.


In total, 9120 and 8181 IE patients were included in case-crossover design and self-controlled case series design, respectively. In case-crossover design, 277 cases and 249 controls received IDTs during the exposure period, and the odds ratio was 1.12 (95% Confidence Interval (CI): 0.94-1.34) for 4 weeks. In self-controlled case series design, we observed that 407 IE occurred during the first four weeks after IDTs, and the age-adjusted incidence rate ratio was 1.14 (95% CI: 1.02-1.26) for 1-4 weeks after IDTs.


In both study designs, we did not observe a clinically larger risk for IE in the short periods after IDTs. We also found no association between IDTs and IE among high-risk patients. Therefore, antibiotic prophylaxis for prevention of IE is not required for the Taiwanese population.




October 5, 2018 at 1:40 pm

Criteria for Identifying Patients With Staphylococcus aureus Bacteremia Who Are at Low Risk of Endocarditis: A Systematic Review

Open Forum Infectious Diseases Octoboer 1, 2017 V.4 N.4

This systematic review examines the methods and results of recent studies reporting clinical criteria able to identify patients with Staphylococcus aureus bacteremia who are at very low risk of endocarditis.

We searched PubMed, EMBASE, and the Cochrane Collaboration CENTRAL database for articles published after March 1994 using a combination of MeSH and free text search terms for S. aureus AND bacteremia AND endocarditis.

Studies were included if they presented a combination of clinical and microbiological criteria with a negative likelihood ratio of ≤0.20 for endocarditis.

We found 8 studies employing various criteria and reference standards whose criteria were associated with negative likelihood ratios between 0.00 and 0.19 (corresponding to 0%–5% risk of endocarditis at 20% background prevalence). The benefit of echocardiography for patients fulfilling these criteria is uncertain.



September 29, 2018 at 2:48 pm

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