Posts filed under ‘Infecciones relacionadas a prótesis’

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

Incidence and risk factors for infection in spine surgery: A prospective multicenter study of 1764 instrumented spinal procedures

American Journal of Infection Control January 2018 V.46 N.1 P.8-13

Wenfei Gu, Laiyong Tu, Zhiquan Liang, Zhenbin Wang, Kahaer Aikenmu, Ge Chu, Enfeng Zhang, Jiang Zhao


Surgical site infection (SSI) is a common complication in spinal surgery, imposing a high burden on patients and society. However, information about its characteristics and related risk factors is limited. We designed this prospective, multicenter study to address this issue.


From January 2015 through February 2016, a total of 1764 patients who had spinal trauma or degenerative spinal diseases were treated with instrumented surgeries and followed up for 1 year with complete data. Data on all patients were abstracted from electronic medical records, and SSIs were prospectively inspected and diagnosed by surgeons in our department. Any disagreement among them was settled by the leader of this study. SPSS 19.0 was used to perform the analyses.


A total of 58 patients (3.3%, 58 of 1764) developed SSI; 1.1% had deep SSI, and 2.2% had superficial SSI. Of these, 60.6% (21 of 33) had a polymicrobial cause. Most of them (51 of 58) occurred during hospitalization. The median occurrence time was 3 days after operation (range: 1–123 days). SSI significantly prolonged hospital stays, by 9.3 days on average. The univariate analysis revealed reason for surgery as the only significant risk factor. The multivariate analysis, however, revealed 8 significant risk factors, including higher BMI, surgical site (cervical), surgical approach (posterior), surgery performed in summer, reasons for surgery (degenerative disease), autograft for fusion and fixation, and higher preoperative platelet level.


Identification of these risk factors aids in stratifying preoperative risk to reduce SSI incidence. In addition, the results could be used in counseling patients and their families during the consent process.



October 2, 2018 at 3:36 pm

The Leukocyte Esterase Test Strip Is a Poor Rule-Out Test for Periprosthetic Joint Infection

Journal of Arthroplasty August 2018 V.33 N.8 P.2571–2574

Carl A. Deirmengian, Lihua Liang, John P. Rosenberger, Tony R. Joaquim, Martin R. Gould, Patrick A. Citrano, Keith W. Kardos


The urinary leukocyte esterase (LE) test strip has been suggested as a good screening test for periprosthetic joint infection (PJI). The purpose of this study is to compare the diagnostic profile of LE assays from different manufacturers and determine whether the LE test strip is a good rule-out test.


Synovial fluid samples (N = 344), sent to 1 laboratory for PJI testing, were used in this prospective study. Four different tests for synovial fluid LE were simultaneously evaluated for their performance in detecting white blood cell (WBC) positive samples (>3000 cells/µL).


Both neutrophil elastase immunoassays demonstrated greater sensitivity than urinary LE test strips (92.0% and 90.8% vs 72.4% and 80.3%; all P < 0.011). Fifty-three percent of false-negative urinary LE test strip results clearly missed the presence of elevated levels of synovial fluid LE. Invalid urinary LE test strip results were 4-fold more likely among WBC (+) compared with WBC (−) samples (27.0% vs 6.8%; P < 0.0001). The combined failure to detect an elevated WBC count, because of either false-negative or invalid results, was 47.1% and 41.4% for the Roche and Siemens test strips, respectively.


This study agrees with the existing literature demonstrating that the LE test strips are among the lowest sensitivity tests for PJI. The urinary LE tests strips should not be used to rule-out PJI, as they often fail to detect abundant levels of LE in synovial fluid. Instead, it is more appropriate to use the (++) LE test strip result as a secondary confirmatory rule-in test for PJI because of its high specificity.



September 29, 2018 at 10:36 am

The Role of One-Stage Exchange for Prosthetic Joint Infection.

Curr Rev Musculoskelet Med. July 9, 2018

Rowan FE1,2, Donaldson MJ3,4, Pietrzak JR3,4, Haddad FS3,4.

Author information

1 Department of Orthopaedic Surgery, University College London Hospital, 250 Euston Road, London, NW1 2PG, UK.

2 The Princess Grace Hospital, 42-52 Nottingham Place, Marylebone, London, W1U 5NY, UK.

3 Department of Orthopaedic Surgery, University College London Hospital, 250 Euston Road, London, NW1 2PG, UK.

4 The Princess Grace Hospital, 42-52 Nottingham Place, Marylebone, London, W1U 5NY, UK.



In an era of increasing numbers of hip and knee replacements, strategies to manage prosthetic joint infection (PJI) that are effective at infection control with good patient-reported outcomes and cost containment for health systems are needed. Interest in single-stage exchange for PJI is rising and we assess evidence from the last 5 years related to this treatment strategy.


Only five series for total knee replacement and ten series for total hip replacement have been reported in the last five years. More review articles and opinion pieces have been written. Reinfection rates in these recent studies range from 0 to 65%, but a meta-analysis and systematic review of all studies showed a reinfection rate of 7.6% (95% CI 3.4-13.1) and 8.8% (95% CI 7.2-10.6) for single-stage and two-stage revisions respectively. There is emerging evidence to support single-stage revision in the setting of significant bony deficiency and atypical PJIs such as fungal infections. Prospective randomised studies are recruiting and are necessary to guide the direction of single-stage revision selection criteria. The onus of surgical excellence in mechanical removal of implants, necrotic tissue, and biofilms lies with the arthroplasty surgeon and must remain the cornerstone of treatment. Single-stage revision may be considered the first-line treatment for all PJIs unless the organism is unknown, the patient is systemically septic, or there is a poor tissue envelope.


September 2, 2018 at 7:02 pm

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