Posts filed under ‘Resistencia bacteriana’

Clinical review: new technologies for prevention of intravascular catheter-related infections.

Crit Care. 2004 Jun;8(3):157-62.

Cicalini S1, Palmieri F, Petrosillo N.

12nd Infectious Diseases Unit, Istituto Nazionale per le Malattie Infettive Lazzaro Spallanzani, IRCCS, Rome, Italy.


Intravascular catheters have become essential devices for the management of critically and chronically ill patients.

However, their use is often associated with serious infectious complications, mostly catheter-related bloodstream infection (CRBSI), resulting in significant morbidity, increased duration of hospitalization, and additional medical costs.

The majority of CRBSIs are associated with central venous catheters (CVCs), and the relative risk for CRBSI is significantly greater with CVCs than with peripheral venous catheters.

However, most CVC-related infections are preventable, and different measures have been implemented to reduce the risk for CRBSI, including maximal barrier precautions during catheter insertion, catheter site maintenance, and hub handling.

The focus of the present review is on new technologies for preventing infections that are directed at CVCs.

New preventive strategies that have been shown to be effective in reducing risk for CRBSI, including the use of catheters and dressings impregnated with antiseptics or antibiotics, the use of new hub models, and the use of antibiotic lock solutions, are briefly described.


April 17, 2014 at 8:42 am

Severe Staphylococcus aureus infection in three pediatric intensive care units: analysis of cases of necrotizing pneumonia.

Arch Argent Pediatr. 2014 Apr;112(2):163-168.

Article in English, Spanish

Taffarel P1, Bonetto G2, Penazzi M1, Jorro Barón F1, Saenz S2, Uranga M3, Mari E4, Pereda R5, Debaisi G1.

1Servicio de Terapia Intensiva, Hospital General de Niños Pedro de Elizalde.

2Servicio de Terapia Intensiva, Hospital de Niños de la Santísima Trinidad, Córdoba.

3Servicio de Infectología, Hospital del Niño de San Justo, San Justo.

4Servicio de Terapia Intensiva, Hospital del Niño de San Justo, San Justo.

5Servicio de Microbiología, Hospital General de Niños Pedro de Elizalde.


Staphylococcus aureus frequently affects human beings. Among clinical manifestations, necrotizing pneumonia is associated with a high mortality rate.

Our objective is to describe the progress of severe Staphylococcus aureus infections in three intensive care units and analyze cases ofnecrotizing pneumonia in the period ranging from January 2011 to March 2013.

Forty-three patients were studied, 76.7% had a community-acquired infection, and 31 had community-acquired methicillin-resistant Staphylococcus aureus.

The main reason for admission was respiratory failure. Bacteremia was confirmed in 55.8% of cases. Mechanical ventilation was required in 86% of admitted patients, while 27 patients developed septic shock.

The length of stay in the intensive care unit was 13 (5-25) days, and the mortality rate was 14%. Necrotizing pneumonia was observed in 51% of cases.

Conclusion. A high rate of community-acquired infection was identified. Necrotizing pneumonia was associated with a worse clinical course.



April 17, 2014 at 8:38 am

A systematic review of risk factors associated with surgical site infections among surgical patients.

PLoS One. 2013 Dec 18;8(12):e83743.

Korol E1, Johnston K1, Waser N1, Sifakis F2, Jafri HS2, Lo M2, Kyaw MH2.

1Oxford Outcomes, Vancouver, British Columbia, Canada.

2MedImmune, Gaithersburg, Maryland, United States of America.



Surgical site infection (SSI) complicates 2-5% of surgeries in the United States. Severity of SSI ranges from superficial skin infection to life-threatening conditions such as severe sepsis, and SSIs are responsible for increased morbidity, mortality, and economic burden associated with surgery. Staphylococcus aureus (S. aureus) is a commonly-isolated organism for SSI, and methicillin-resistant S. aureus SSI incidence is increasing globally.


The objective of this systematic review was to characterize risk factors for SSI within observational studies describing incidence of SSI in a real-world setting.


An initial search identified 328 titles published in 2002-2012; 57 were identified as relevant for data extraction. Extracted information included study design and methodology, reported cumulative incidence and post-surgical time until onset of SSI, and odds ratios and associated variability for all factors considered in univariate and/or multivariable analyses.


Median SSI incidence was 3.7%, ranging from 0.1% to 50.4%. Incidence of overall SSI and S. aureus SSI were both highest in tumor-related and transplant surgeries. Median time until SSI onset was 17.0 days, with longer time-to-onset for orthopedic and transplant surgeries. Risk factors consistently identified as associated with SSI included co-morbidities, advanced age, risk indices, patient frailty, and surgery complexity. Thirteen studies considered diabetes as a risk factor in multivariable analysis; 85% found a significant association with SSI, with odds ratios ranging from 1.5-24.3. Longer surgeries were associated with increased SSI risk, with a median odds ratio of 2.3 across 11 studies reporting significant results.


In a broad review of published literature, risk factors for SSI were characterized as describing reduced fitness, patient frailty, surgery duration, and complexity. Recognition of risk factors frequently associated with SSI allows for identification of such patients with the greatest need for optimal preventive measures to be identified and pre-treatment prior to surgery.




April 15, 2014 at 8:33 am

Assessment of prophylactic antibiotic use in patients with surgical site infections.

Hosp Pharm. 2013 Jul;48(7):560-7.

Goede WJ1, Lovely JK1, Thompson RL2, Cima RR3.

1Pharmacy Services.

2Division of Infectious Diseases.

3Division of Colon and Rectal Surgery, Mayo Clinic, Rochester, Minnesota. Corresponding author: Jenna K. Lovely, PharmD, Pharmacy Services, Mayo Clinic, 200 First Street SW, Rochester MN 55905; e-mail: .



Surgical site infections (SSIs) are the leading cause of hospital-acquired infections and are associated with substantial health care costs, with increased morbidity and death. The Surgical Care Improvement Project (SCIP) contains standards that are nationally reported with the aim of improving patient outcomes after surgery. Our institution’s standards for antimicrobial prophylaxis in the perioperative period are more stringent than these measures and may be considered “beyond SCIP.” The 4 elements of appropriate antimicrobial prophylaxis are timing, antibiotic selection, dosing, and intraoperative redosing.


To quantify antimicrobial SSI prophylaxis compliance in accordance with institutional standards and to identify potential opportunities for improvement.


Patients aged 18 years or older were included if they had an SSI between January 1, 2009, and June 30, 2010, according to the database maintained prospectively by the Infection Prevention and Control Unit. Adherence to our institution’s practice standards was assessed through analysis of antibiotics administered-timing in relation to the incision, closure, and tourniquet inflation times for the procedure and antibiotic selection, dose, and redosing.


Overall noncompliance with all 4 elements of antimicrobial prophylaxis was 75.4% among the 760 cases. Repeat dosing had the greatest noncompliance (45.1%); antibiotic selection had the lowest incidence of noncompliance (10.8%).


Noncompliance existed in each element of antimicrobial SSI prophylaxis, with antibiotic redosing leading in noncompliance. With the implementation of tools to assist the surgical team in following institutional standards, noncompliance will likely decline and additional research opportunities will exist.


April 13, 2014 at 10:31 am

Prospective Multicenter Study of Community-Associated Skin and Skin Structure Infections due to Methicillin-Resistant Staphylococcus aureus in Buenos Aires, Argentina

PLoS one PLoS One. 2013 Nov 20;8(11):e78303

López Furst MJ1, de Vedia L, Fernández S, Gardella N, Ganaha MC, Prieto S, Carbone E, Lista N, Rotryng F, Morera GI, Mollerach M, Stryjewski ME; Grupo de Estudio de Infecciones de Piel y Estructuras Relacionadas por Staphylococcus aureus meticilino-resistente de la Comunidad, Sociedad Argentina de Infectología.

Collaborators (66)

Fernández S, Gardella N, Mollerach M, Stryjewski ME, Yahni D, Carbone E, Nadal P, Salvador P, Targa L, Martinez JV, Cullen J, Iribas JL, Méndez E, Morera GI, Gelman LD, Tanco AJ, Costa R, Moyano M, Nicolás E, Fernández JA, Ameri D, Duarte A, Rolón MJ, Sisto A, Houssay B, Lopez V, Lopardo G, Tempelsman R, Ricci B, Sívori O, Muñiz FJ, de Vedia L, de Luján NS, Prieto S, Ruzo G, del Plata M, De Wouters L, Gordóvil M, Vallejos M, Santojanni F, Alfonso C, D’Alessandro DC, Scapellato PG, Burgos M, Gill D, Longo L, Rodríguez V, Alvarez S, Galia C, Rotryng F, Sarfield V, Pryluka D, Commisso MS, Ganaha MC, Gullo H, Fernandez G, Retes AM, Méndez J, Cantarella S, Gutiérrez M, Furst MJ, Landaburu MF, Puentes T, Torres C, Zarlenga L, Gentile J.

Unidad de Infectología, Sanatorio Municipal Dr. Julio Méndez, Ciudad Autónoma de Buenos Aires, Argentina.



Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is now the most common cause of skin and skin structure infections (SSSI) in several world regions. In Argentina prospective, multicenter clinical studies have only been conducted in pediatric populations.

Objective Primary

describe the prevalence, clinical and demographic characteristics of adult patients with community acquired SSSI due to MRSA; secondary: molecular evaluation of CA-MRSA strains. Patients with MRSA were compared to those without MRSA.

Materials and Methods

Prospective, observational, multicenter, epidemiologic study, with molecular analysis, conducted at 19 sites in Argentina (18 in Buenos Aires) between March 2010 and October 2011. Patients were included if they were 14 years, were diagnosed with SSSI, a culture was obtained, and there had no significant healthcare contact identified. A logistic regression model was used to identify factors associated with CA-MRSA. Pulse field types, SCCmec, and PVL status were also determined.


A total of 311 patients were included. CA-MRSA was isolated in 70% (218/311) of patients. Clinical variables independently associated with CA-MRSA were: presence of purulent lesion (OR 3.29; 95%CI 1.67, 6.49) and age ,50 years (OR 2.39; 95%CI 1.22, 4.70). The vast majority of CA-MRSA strains causing SSSI carried PVL genes (95%) and were SCCmec type IV. The sequence type CA-MRSA ST30 spa t019 was the predominant clone.


CA-MRSA is now the most common cause of SSSI in our adult patients without healthcare contact. ST30, SCCmec IV, PVL+, spa t019 is the predominant clone in Buenos Aires, Argentina.


April 9, 2014 at 8:30 am

Carbapenemase-producing bacteria in companion animals: a public health concern on the horizon

Journal of Antimicrobial Chemotherapy My 2014 V.69 N.5 P.1155-1157

Sam Abraham1,*, Hui San Wong1, John Turnidge2,3, James R. Johnson4 and Darren J. Trott1

1School of Animal and Veterinary Sciences, University of Adelaide, South Australia 5371, Australia

2Women’s and Children’s Hospital, Adelaide, South Australia 5006, Australia

3Departments of Pathology, Paediatrics and Molecular and Biomedical Sciences, University of Adelaide, Adelaide, South Australia, Australia

4Veterans Affairs Medical Center and University of Minnesota, Minneapolis, MN, USA

Clinical infections attributed to carbapenemase-producing bacteria are a pressing public health concern owing to limited therapeutic options and linked antimicrobial resistance.

In recent years, studies have reported the emergence and spread of carbapenemase-producing Enterobacteriaceae and their public health impact. This has been closely followed by the global dissemination of highly resistant and virulent zooanthroponotic extraintestinal pathogenic Escherichia coli (ExPEC) ST131 clones.

It has also been hypothesized that companion animals may act as a reservoir for Gram-negative multidrug-resistant pathogens in the community. Two recent reports have documented the emergence of carbapenemase-producing bacteria in companion animals.

This phenomenon is of great concern because of the close contact between humans and their pets, and the potential for cross-species transmission.

This scenario suggests a role for multifaceted control of Gram-negative multidrug-resistant infections in companion animals.

This short article addresses this issue and identifies steps that could facilitate this process.


April 8, 2014 at 1:57 pm

Effect of Surgical Safety checklist implementation on the occurrence of postoperative complications in orthopedic patients.

Isr Med Assoc J. 2014 Jan;16(1):20-5.

Boaz M1, Bermant A2, Ezri T3, Lakstein D2, Berlovitz Y4, Laniado I3, Feldbrin Z2.

1Epidemiology Research Unit, Wolfson Medical Center, Holon, Israel.

2Department of Orthopedics, Wolfson Medical Center, Holon, Israel.

3Department of Anesthesiology and Surgery, Wolfson Medical Center, Holon, Israel.

4Directorate, Wolfson Medical Center, Holon, Israel.



Surgical adverse events are errors that emerge during perioperative patient care. The World Health Organization recently published “Guidelines for Safe Surgery.”


To estimate the effect of implementation of a safety checklist in an orthopedic surgical department.


We conducted a single-center cross-sectional study to compare the incidence of complications prior to and following implementation of the Guidelines for Safe Surgery checklist. The medical records of all consecutive adult patients admitted to the orthopedics department at Wolfson Medical Center during the period 1 July 2008 to 1 January 2009 (control group) and from 1 January 2009 to 1 July 2009 (study group) were reviewed. The occurrences of all complications were compared between the two groups.


The records of 760 patients (380 in each group) hospitalized during this 12 month period were analyzed. Postoperative fever occurred in 5.3% versus 10.6% of patients with and without the checklist respectively (P = 0.008). Significantly more patients received only postoperative prophylactic antibiotics rather than both pre-and postoperative antibiotic treatment prior to implementation of the checklist (3.2% versus 0%, P = 0.004). In addition, a statistically non-significant 34% decrease in the rate of surgical wound infection was also detected in the checklist group. In a logistic regression model of postoperative fever, the checklist emerged as a significant independent predictor of this outcome: odds ratio 0.53, 95% confidence interval 0.29-0.96, P = 0.037.


A significant reduction in postoperative fever after the implementation of the surgical safety checklist occurred. It is possible that the improved usage of preoperative prophylactic antibiotics may explain the reduction in postoperative fever.


April 6, 2014 at 4:37 pm

Control strategies to prevent total hip replacement-related infections: a systematic review and mixed treatment comparison.

BMJ Open. 2014 Mar 6;4(3):e003978.

Zheng H1, Barnett AG, Merollini K, Sutton A, Cooper N, Berendt T, Wilson J, Graves N.

1Australian Centre for Health Services Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.



To synthesise the available evidence and estimate the comparative efficacy of control strategies to prevent total hip replacement (THR)-related surgical site infections (SSIs) using a mixed treatment comparison.


Systematic review and mixed treatment comparison.


Hospital and other healthcare settings.


Patients undergoing THR.


The number of THR-related SSIs occurring following the surgical operation.


12 studies involving 123 788 THRs and 9 infection control strategies were identified. The strategy of ‘systemic antibiotics+antibiotic-impregnated cement+conventional ventilation’ significantly reduced the risk of THR-related SSI compared with the referent strategy (no systemic antibiotics+plain cement+conventional ventilation), OR 0.13 (95% credible interval (CrI) 0.03-0.35), and had the highest probability (47-64%) and highest median rank of being the most effective strategy. There was some evidence to suggest that ‘systemic antibiotics+antibiotic-impregnated cement+laminar airflow’ could potentially increase infection risk compared with ‘systemic antibiotics+antibiotic-impregnated cement+conventional ventilation’, 1.96 (95% CrI 0.52-5.37). There was no high-quality evidence that antibiotic-impregnated cement without systemic antibiotic prophylaxis was effective in reducing infection compared with plain cement with systemic antibiotics, 1.28 (95% CrI 0.38-3.38).


We found no convincing evidence in favour of the use of laminar airflow over conventional ventilation for prevention of THR-related SSIs, yet laminar airflow is costly and widely used. Antibiotic-impregnated cement without systemic antibiotics may not be effective in reducing THR-related SSIs. The combination with the highest confidence for reducing SSIs was ‘systemic antibiotics+antibiotic-impregnated cement+conventional ventilation’. Our evidence synthesis underscores the need to review current guidelines based on the available evidence, and to conduct further high-quality double-blind randomised controlled trials to better inform the current clinical guidelines and practice for prevention of THR-related SSIs.



April 6, 2014 at 4:35 pm

Comparative activities of telavancin combined with nafcillin, imipenem, and gentamicin against Staphylococcus aureus.

Antimicrob Agents Chemother. 2013 Jun;57(6):2678-83.

Leonard SN1, Supple ME, Gandhi RG, Patel MD.

Author information

1Northeastern University, Bouvé College of Health Sciences, School of Pharmacy, Boston, Massachusetts, USA.


Beta-lactams enhance the killing activity of vancomycin. Due to structural and mechanistic similarities between vancomycin and telavancin, we investigated the activity of telavancin combined with nafcillin and imipenem compared to the known synergistic combination of telavancin and gentamicin.

Thirty strains of Staphylococcus aureus, 10 methicillin-susceptible S. aureus (MSSA), 10 methicillin-resistant S. aureus (MRSA), and 10 heterogeneously vancomycin-intermediate S. aureus (hVISA), were tested for synergy by time-kill methodology.

Six strains (2 each of MSSA, MRSA, and hVISA) were further evaluated in an in vitro pharmacokinetic/pharmacodynamic (PK/PD) model with simulated regimens of 10 mg/kg of body weight of telavancin once daily alone and combined with 2 g nafcillin every 4 h, 500 mg imipenem every 6 h, or 5 mg/kg gentamicin once daily over 72 h.

In the synergy test, 67% of strains displayed synergy with the combination of telavancin and gentamicin, 70% with telavancin and nafcillin, and 63% with telavancin and imipenem.

In the PK/PD model, the activities of all three combinations against MRSA and hVISA were superior to all individual drugs alone (P ≤ 0.002) and were similar to each other (P ≥ 0.187).

The activities of all three combinations against MSSA were generally similar to each other except for one strain where the combination of telavancin and imipenem was superior to all other regimens (P ≤ 0.011).

The activity of the combination of telavancin and beta-lactam agents was similar to that of telavancin and gentamicin against S. aureus, including resistant strains.

Because beta-lactam combinations are less likely to be nephrotoxic than telavancin plus gentamicin, these beta-lactam combinations may have clinical utility.


April 5, 2014 at 3:59 pm

In vitro and in vivo antibacterial activities of cranberry press cake extracts alone or in combination with β-lactams against Staphylococcus aureus.

BMC Complement Altern Med. 2013 Apr 27;13:90.

Diarra MS1, Block G, Rempel H, Oomah BD, Harrison J, McCallum J, Boulanger S, Brouillette É, Gattuso M, Malouin F.

1Pacific Agri-Food Research Center, Agriculture and Agri-Food Canada, Agassiz, BC V0M 1A0, Canada.



Cranberry fruits possess many biological activities partly due to their various phenolic compounds; however the underlying modes of action are poorly understood. We studied the effect of cranberry fruit extracts on the gene expression of Staphylococcus aureus to identify specific cellular processes involved in the antibacterial action.


Transcriptional profiles of four S. aureus strains grown in broth supplemented or not with 2 mg/ml of a commercial cranberry preparation (Nutricran®90) were compared using DNA arrays to reveal gene modulations serving as markers for biological activity. Ethanol extracted pressed cakes from fresh fruits also produced various fractions and their effects on marker genes were demonstrated by qPCR. Minimal inhibitory concentrations (MICs) of the most effective cranberry fraction (FC111) were determined against multiple S. aureus strains and drug interactions with β-lactam antibiotics were also evaluated. Incorporation assays with [(3)H]-radiolabeled precursors were performed to evaluate the effect of FC111 on DNA, RNA, peptidoglycan (PG) and protein biosynthesis.


Treatment of S. aureus with Nutricran®90 or FC111 revealed a transcriptional signature typical of PG-acting antibiotics (up-regulation of genes vraR/S, murZ, lytM, pbp2, sgtB, fmt). The effect of FC111 on PG was confirmed by the marked inhibition of incorporation of D-[(3)H]alanine. The combination of β-lactams and FC111 in checkerboard assays revealed a synergistic activity against S. aureus including strain MRSA COL, which showed a 512-fold drop of amoxicillin MIC in the presence of FC111 at MIC/8. Finally, a therapeutic proof of concept was established in a mouse mastitis model of infection. S. aureus-infected mammary glands were treated with amoxicillin, FC111 or a combination of both; only the combination significantly reduced bacterial counts from infected glands (P<0.05) compared to the untreated mice.


The cranberry fraction FC111 affects PG synthesis of S. aureus and acts in synergy with β-lactam antibiotics. Such a fraction easily obtained from poorly exploited press-cake residues, may find interesting applications in the agri-food sector and help reduce antibiotic usage in animal food production.


April 5, 2014 at 3:57 pm

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