The role of antimicrobial stewardship programs in the control of bacterial resistance                     

JUAN PASQUAU, SVETLANA SADYRBAEVA, SAMANTHA E. DE JESÚS, CARMEN HIDALGO-TENORIO          

In order to improve infection prognosis and reduce the existing microbial resistance problem (a challenge similar to that of climate change), a higher implication of the Administration, an increased level of social awareness and the development of specific corporate networks, including the pharmaceutical industry, is needed. However, we must first consolidate Antimicrobial Stewardship Programmes with experts who seek to improve antibiotic therapy effectivity in severe infections and to reduce global antibiotic exposure.

Rev Esp Quimioter 2016; 29(Suppl. 1):47-51 [pdf]

Prosthetic joint infection in patients with hip fracture. Differences from infection of elective prosthesis                     

JOSÉ Mª BARBERO, EDUARDO MONTERO, ALFONSO VALLÉS, MIGUEL ÁNGEL PLASENCIA, JUAN ROMANYK, JOAQUÍN LÓPEZ          

Introduction. Most publications about prosthetic joint infections (PJI) are referred to elective prosthesis and they exclude arthroplasties due to hip fracture.
Methods. We conducted a descriptive study about prosthetic joint infections after joint fracture in Alcalá de Henares Hospital (Madrid) between 2009 and 2014 and we compared with elective prosthetic infections in the same period.
Results. There were 30 PJI after hip fracture and 14 elective PJI. The incidence of infection was 4.7% in arthroplasties due to hip fracture from 1.3% in elective prosthesis (RR 3.8, p=0.005). The PJI after fracture affected older patients (82.5 years vs 71.5, p=0.006), with greater comorbidity (5.4 vs 3.6, p=0.003), higher anesthetic risk (ASA>2 70% vs 21.4%, p=0.004) and higher incidence of dementia (50% vs 0%, p=0.02). Staphylococcus aureus was the most common causative agent in both groups, but there was higher incidence of Gram negative-cases in PJI after fracture group (43.3% vs 21.4%, p no significance) and cefazolin-resistance (63.3% vs 28.6%, p=0.03). In logistic regression analysis the treatment had less chance of success in PJI after fracture than elective PJI (33.3% vs 78.6%, OR 0.09, p=0.06).
Conclusions. The PJI after fracture are more frequent than elective PJI, affect older patients, with poor general condition, are produced by more resistant bacteria and have worst evolution than EPJI.

Rev Esp Quimioter 2016; 29(5):273-277 [pdf]

About microbiological methods for detection of oxacillin resistance in coagulase-negative staphylococci                     

MIGUEL FAJARDO, ROCÍO HIDALGO, JORGE GAITÁN, ROSA SÁNCHEZ-SILOS, PALOMA MARTÍN-CORDERO          

Introduction. Coagulase-negative staphylococci (CoNS) take part of the human skin and mucous membranes, but they are also involving in infections with the increasing use of prosthetic, indwelling devices or intravascular catheter-related bacteraemia. They are more resistance than Staphylococcus aureus against a wide range of antimicrobial agents, and it have been observed an increase in morbidity and mortality of patients with incorrect treatment.
Material and methods. To analyze the results obtained by different commercial techniques: two automatic microdilution systems (MicroScan and Vitek2 Compact), PBP2a agglutiation test, with and without 1 μg oxacillin disk induction, and detection of mecA gene by nucleic acids amplification techniques, for the diagnosis of methicillin resistance staphylococci in 170 strains of CoNS isolated from blood cultures.
Results. One hundred and seventy methicillin resistance staphylococci were detected by MicroScan, 167 strains by Vitek 2 Compact, 115 strains were PBP2a positive without oxacillin induction and 168 after oxacillin induction. Finally, 167 strains were mecA gene positive detected by nucleic acids amplification techniques.
Conclusions. It is necessary to do oxacillin induction before PBP2a test to avoid false negatives. There are a great variability in the phenotypic expression of methicillin resistance in CoNS.

Rev Esp Quimioter 2016; 29(5):244-248 [pdf]

Epidemiology of the infection by resistant Gram-positive microorganisms                    

EMILIA CERCENADO          

Resistance among Gram-positive microorganisms to classical and new antimicrobials is a therapeutic threat. In Spain, methicillin resistance among Staphylococcus aureus (25-30%) and coagulase-negative staphylococci (50-60%) seems to have stabilized in the last decade. Among enterococci, vancomycin resistance is less than 5%. Both linezolid and daptomycin, in general, show good activity against these microorganisms. However, the resistance rates of Staphylococcus epidermidis to linezolid (20.9%), and of Enterococcus faecium to daptomycin (10.5%) in isolates from intensive care units are a worrying.

Rev Esp Quimioter 2016; 29(Suppl. 1):6-9 [pdf]

Directed therapeutic approach to Staphylococcus aureus infections. Clinical aspects of prescription                     

FRANCISCO CARMONA-TORRE, MARTA RUA, JOSÉ LUIS DEL POZO          

 

Infections caused by Staphylococcus aureus have had classically an important impact in morbidity and mortality in the nosocomial and community scene. The description of methicillin resistance among nosocomial isolates of S. aureus and his widespread diffusion has become methicillin-resistant S. aureus (MRSA) in one of the most common causes of bacterial nosocomial infections. In the last years MRSA strains have also emergence in the community. This together with a progressive increase in resistance to antibiotics used classically has become vancomycin in the treatment of choice in most cases according to clinical guidelines.
As a result, a progressive rise in the minimum inhibitory concentration (MIC) to vancomycin has been reported. In this context strains with intermediate susceptibility to vancomycin (MIC 8-4 mg/L) and heteroresistance have been noted. These strains are associated with a higher risk of treatment failure when using vancomycin.
Among isolates of S. aureus susceptible to vancomycin there has been described stains with elevated MICs (≥1.5 mg/L). It is controversial if the presence of these strains has an impact on clinical outcome if treatment with vancomycin or β-lactams is prescribed.
The development of new antibiotics with activity against MRSA and exploring synergies offer a promising alternative to treatment with vancomycin.

Rev Esp Quimioter 2016; 29(Suppl. 1):15-20 [pdf]