Infección nosocomial en las unidades de cuidados intensivos

Nosocomial infections (NI) still have a high incidence in intensive care units (ICUs), and are becoming one of the most important problems in these units. It is well known that these infections are a major cause of morbidity and mortality in critically ill patients, and are associated with increases in the length of stay and excessive hospital costs. Based on the data from the ENVIN-UCI study, the rates and aetiology of the main nosocomial infections have been described, and include ventilator-associated pneumonia, urinary tract infection, and both primary and catheter related bloodstream infections, as well as the incidence of multidrug-resistant bacteria. A literature review on the impact of different nosocomial infections in critically ill patients is also presented. Infection control programs such as zero bacteraemia and pneumonia have been also analysed, and show a significant decrease in NI rates in ICUs.     

Infecciones producidas por Clostridium difficile

The epidemiology of Clostridium difficile infections (CDIs) has dramatically changed over the last decade in both North America and Europe, and it has become more frequent, more severe, more refractory to standard therapy, and more likely to relapse. These changes have been associated with the emergence of a “hypervirulent” strain known as BI/NAP1/027 which has become endemic in some areas, although, other hypervirulent genotypes (e.g. PCR ribotype 078) have also been described. To reduce the incidence of CDIs, the diagnostic guidelines on diagnosis and treatment methods have been recently updated. The aim of this review is to highlight the recent epidemiological data on CDIs and to provide an overview of the pathogenicity of the infection, diagnostic approaches, old and new treatment options, and current knowledge of infection control measures.     

La infección neonatal tardía por Streptococcus agalactiae en el área de Barcelona (1996-2010)

Objetive

To study the characteristics and evolution of group B Streptococcus (GBS) late-onset diseases, over a period of 15 years in 8 hospitals the Barcelona area and analyze the possible impact of prophylactic measures for the prevention of early-onset neonatal infections.

Methods

Retrospective review of all patients diagnosed with late-onset neonatal disease due to GBS from 1996 to 2010.

Results

A total of 143 patients were diagnosed. Of these, 51 were born in others hospitals. The overalll incidence was 0.42 per 1000 live births, varying between 0.14‰ in the year 2000 and 0.80‰ in 2009. A slight but sustained tendency of increased risk was observed over the years, 6.9% in the overall disease (with no statistical significance). Sepsis/bacteremia was detected in 63.6% of the newborns, meningitis in 32.8%, and arthritis/osteomyelitis in 3.5%. In cases with known obstetrics dates, 53% of mothers had been colonized by GBS during pregnancy, 53.8% received intrapartum antibiotic prophylaxis, and 41.2% had some obstetric risk factors, particularly premature birth in 35.9%. There was a 2.8% mortality rate in the neonates, and predominant serotypes were III and Ia.

Conclusions

The incidence of GBS late-onset disease has not decreased despite the control practices of early-onset disease, and possibility of this appearing must be taken into account.     

Aumento significativo de la colonización por Staphylococcus aureus entre los estudiantes de medicina durante la realización de las prácticas en el hospital

Introduction

Staphylococcus aureus is a pathogen of major concern. The emergence of methicillin-resistant S. aureus (MRSA) has increasingly complicated the therapeutic approach of hospital-acquired infections. Surveillance of MRSA and control measures must be implemented in different healthcare settings, including screening programs for carriers. Our first aim was to determine the prevalence of methicillin-susceptible S. aureus (MSSA) and MRSA nasal carriage in medical students from the Clínico San Carlos Hospital (Madrid). As the MRSA carrier rate in healthcare workers is higher than in the general population, we hypothesised that carrier rate could be increased during their clinical practice in their last three years.

Methods

We performed an epidemiologic al study of the prevalence of S. aureus colonisation among a group of medical students, who were sampled in 2008 in their third-year, and in 2012 when this class was in its sixth year.

Results

We have found a significant increase in MSSA carriage, from 27% to 46%. There were no MRSA colonisations in the third-year, but one was found in the sixth-year group. The large majority of strains (89%) of strains were resistant to penicillin, and 27% to erythromycin and clindamycin. As 19 coagulase-negative Staphylococcus MR were also identified, a horizontal transfer of genes, such as mecA gene to S. aureus, could have occurred.

Conclusions

Medical students are both, at risk for acquiring, and a potential source of nosocomial pathogens, mainly MSSA. Therefore, they should take special care for hygienic precautions, such as frequent and proper hand washing, while working in the hospital.     

Diagnóstico microbiológico de las infecciones por Mycoplasma

The microbiological diagnosis of mycoplasma and ureaplasma infections has always been limited due to the fastidious growth of these microorganisms, as well as the lack of comercially prepared growth media, absence of rapid diagnostic procedures, and the clinical perception that these organisms are less significant in the infectious diseases setting. During the last few years, this situation has substantially improved due to the commercial availability of culture media, the development of rapid serological techniques, and, in particular, to the introduction of nucleic acid amplification assays, commercially available or “in-house” preparations. Despite the lack of proper standardisation and validation of the molecular and serological techniques, methodological advances have led to an increased detection of these microorganisms and, consequently, a greater appreciation of their clinical relevance.     

Factores asociados y análisis descriptivo de la endocarditis infecciosa adquirida en el entorno hospitalario de un centro terciario de referencia

Introduction and objectives

The primary aim of this study was to evaluate associated factors, clinical features and prognosis of healthcare-related infective endocarditis cases compared with community-acquired and intravenous drug user-related episodes. Changes in the distribution of healthcare-related infective endocarditis were also analysed over time in our setting.

Methods

A prospective, observational, comparative study was performed. We included all the cases of infective endocarditis from January 2003 to June 2010, which were then classified into 2 groups: group 1: community-acquired and intravenous drug user origin, and group 2: nosocomial and non-nosocomial healthcare-related cases. The episodes were classified into 2 periods: period I: January/2003-June/2006 and period II: July/2006-June 2010. Univariate and multivariate analyses were performed.

Results

A total of 212 cases were included (group 1: 138, group 2: 74). The variables of age (risk ratio 1.026; 95% CI, 1.003 to 1.049), Charlson index (risk radio 1.242; 95% CI, 1.067 to 1.445), and previous heart surgery (risk ratio 2.522; 95% CI, 1.353 to 4.701) were independently associated with healthcare-related infective endocarditis on multivariate analysis. A non-significant increase was observed in healthcare-related cases of infective endocarditis in period II (40/104; 38.4% vs. 34/108; 31.4%).

Conclusions

The recent increase in healthcare-related infective endocarditis seems to be associated with the use of invasive procedures in elderly patients with prosthetic cardiac valve, and those with a greater number of underlying diseases, especially patients with chronic renal failure on haemodialysis.     

Papel del ambiente hospitalario y los equipamientos en la transmisión de las infecciones nosocomiales

The hospital environment is both a reservoir and source of infection for the hospital patient. Several areas around the patient should be considered: air, toilet water coming into contact with the patient, staff and medical devices, food, surfaces, and instruments contacting the patient's skin and mucosa, and sterile solutions. There are pathogens classically associated with each mode of transmission and environmental reservoir, but multi-resistant microorganisms have also been recently been associated with environmental acquisition.     

Erradicación de un brote nosocomial de infecciones por Acinetobacter baumannii multirresistente tras el ajuste de cargas de trabajo y refuerzo de precauciones específicas

Introduction

During 2009, an outbreak of multidrug-resistant Acinetobacter baumannii (MDR A. baumannii) infections was detected in a 27-bed intensive care unit, resulting in 25 cases being infected.

Methods

A matched case-control study was conducted to identify risk factors for infection. The colonization pressure, or the proportion of other patients colonized by MDR A. baumannii, was estimated. TISS-28 and Omega scores of each patient were calculated to evaluate nursing work requirements. Conditional logistic regression analyses were carried out.

Results

Breakdowns in hand washing and glove use were observed. Infected patients (cases) were more likely than paired controls to have had longer exposure to invasive devices and antimicrobial treatment. The independent risk factors identified by the multivariate analysis were, mechanical ventilation [odds ratio (OR) = 1.03; 95% confidence interval (CI), 1.01-1.05; P = .01], and exposure to an infected or colonized patient [OR = 1.7; 95% CI, 1.1-2.6; P = .02). A combined infection control strategy was implemented, including strict compliance with isolation precautions, grouping of patients, reinforcing cleaning and disinfection of surfaces, and a decrease in work load. Subsequently, a sharp reduction in the incidence MDR A. baumannii infections was shown. Therapeutic activity scores were significantly higher for cases than for controls.

Conclusion

The results suggest patient-to-patient transmission of MDR A. baumannii. Reinforcement of specific procedures and work load adjustment were essential to eradicate this outbreak.     

Implantación electiva de stent recubierto en la coartación y recoartación en el joven y en el adulto

Introduction and objectives

Stent implantation is an effective therapy for aortic coarctation and recoarctation. However, in adolescents and adults, aortic wall rupture and dissection can occur, as well as aneurysms during follow-up. In order to reduce these complications, we electively implant covered stents.

Methods

Since 2005, we have performed the procedure using femoral access in 17 patients (2 adolescents and 15 adults), 16 electively and 1 as a rescue procedure. We used the Mullins technique in all cases, implanting a NuMED^® covered stent.

Results

Good stent apposition was achieved in all 17 procedures; 8 patients required a distal flare. Gradient was reduced from 40 (16) mmHg to 2 (2) mmHg (P<.001) and lumen diameter increased from 4 (2) mm to 19 (3) mm (P<.001). Two exceptional cases are discussed: one patient with aortic wall rupture who underwent a rescue procedure using a stent within a covered stent and another patient with total obstruction and intercostal aneurysm in whom the outcome was fatal at 48 h postprocedure (autopsy is shown). Four-year clinical follow-up included Doppler echocardiography; an additional imaging technique was required in 13 patients. All patients recovered well and there were no complications.

Conclusions

Covered stents are effective in treating coarctation and recoarctation in adolescents and adults, are the treatment of choice in patients with complex anatomy, and must be available in the operating room as a rescue device when implanting a conventional stent.Full English text available from:www.revespcardiol.org/en     

Viriasis nosocomiales. Virus de la hepatitis,herpesvirus y virus de la gripe

Viruses account for about 5% of all nosocomial infections. Viral cross-infection is most common in infants and children, but also occurs in other groups, including the elderly, institutionalized persons of all ages, immunecompromised hosts, and patients with underlying chronic pulmonary, renal, or cardiac disease. These infections are associated with extended length of hospital stay, as well as considerable morbidity and mortality. The new technology of rapid viral diagnosis allows a more timely and accurate recognition of viral infections, even in the smaller hospital with limited laboratory resources. Early recognition of viral diseases should, in turn, permit the introduction, and further evaluation of specific measures for their control. Influenza vaccination of health care workers is an important prevention strategy for nosocomial infection.     

Diagnóstico microbiológico de las infecciones por Chlamydia spp. y especies relacionadas

Until recently the number of completed genomes belonging to Chlamydia trachomatis was very low, despite its importance in Public Health. Now, there are currently sixty-six completed genomes of C. trachomatis sequenced in different parts of the world. This genomic revolution has helped in understanding its biology, as well as improved the sensitivity and specificity in the diagnosis, and the development of epidemiological tools, not only for in C. trachomatis, but also for related species such as C. pneumoniae and C. psittaci. The diagnosis based on cell culture, serology and microimmunofluorescence is gradually being replaced by molecular techniques based on PCR or real-time PCR. This is because these molecular tests do not have cross-reactions problems and the procedures are easily standardised between laboratories. Moreover, molecular epidemiology tools described recently, such as Multi-Locus Sequence Typing (MLST) and Variable Number Tandem Repeat (VNTR), have increased our knowledge on local and global epidemiology. This article focuses on the impact of the genomics advances achieved over the last few years as applied to the diagnosis, epidemiology and biology of the family Chlamydiaceae family and related species.     

Efectos protectores del aceite de Nigella sativa en la lesión pulmonar inducida por hiperoxia

Background

Oxygen-induced lung injury is believed to lead to the development of bronchopulmonary dysplasia in premature infants. We have evaluated the beneficial effects of Nigella sativa oil (NSO) on rats with hyperoxia-induced lung injury.

Methods

Thirty newborn Sprague-Dawley rats were randomly divided into 3 groups as hyperoxia (95% O₂), hyperoxia + NSO and control (21% O₂). Pups in the hyperoxia + NSO group were administered intraperitoneal NSO at a dose of 4 ml/kg daily during the study period. Histopathologic, immunochemical, and biochemical evaluations (superoxide dismutase [SOD], glutathione peroxidase [GSH-Px], malonaldehyde [MDA] and myeloperoxidase [MPO]) were performed.

Results

In the histopathologic and immunochemical evaluation, severity of lung damage was significantly lower in the hyperoxia + NOS group (P < .05). Tissue GSH-Px and SOD levels were significantly preserved, and MDA, MPO levels were significantly lower in the hyperoxia + NSO group (P < .05).

Conclusion

NSO significantly reduced the severity of lung damage due to hyperoxia.     

Colonización nasal por Staphylococcus aureus en estudiantes de medicina: importancia en la transmisión hospitalaria

Background

Staphylococcus aureus is the main pathogen causing nosocomial infections. Health professionals, including medical students, could be a source of transmission. The aims of the study were to determine the rate of nasal carriage of S. aureus susceptible and resistant to methicillin (MRSA) and evaluate the knowledge and adherence that students had about hand hygiene.

Methods

The study included medical students attached to the Hospital Universitario 12 de Octubre (Madrid, Spain). We collected samples from both nasal vestibules, and the antimicrobial susceptibility was determined on all isolates. Data collection was performed using a self-administered questionnaire that included risk factors for colonization, hygiene habits and knowledge of hand hygiene protocols.

Results

Of the 140 students included, 55 (39.3%) were colonized by S. aureus, and 3 (2,1%) by MRSA. The exposure to antibiotics in the last 3 months was lower in colonized students (12.3% vs. 25.9%, P = .03). Self-assessment showed that 56.4% of students almost never washed their hands before to attending to the first patient, and only 38.6% always washed after examining patients. More than a third (35.7%) ignored the hand hygiene protocol, and 38.6% had not received specific formation.

Conclusions

Medical students should be included in hospital infection control programs. Hand hygiene training should be given to students before they begin their practices in the hospital.     

Infecciones causadas por bacterias grampositivas multirresistentes (Staphylococcus aureus y Enterococcus spp.)

Methicillin -resistant Staphylocccus aureus (MRSA) and multirresistant entorococci are still problematic in nosocomial infections and new challenges have emerged for their containment. MRSA has increased the multiresistant profile; it has been described vancomycin and linezolid resistant isolates and isolates with decreased daptomycin susceptibility. Moreover, new clones (ST398) have emerged, initially associated with piggeries, and new mec variants (mecC) with livestock origin that escape to the detection with current molecular methods based on mecA gene have been detected. In enterococci, linzeolid resistant isolates and isolates with deceased susceptibility to daptomycin have been described. Moreover, ampicillin resistant Enterococcus faecium due to β-lactamase production has been recently found in Europe. Control of MRSA isolates and multiresistant enteroccocci should combined antibiotic stewardship strategies and epidemiological measures, including detection of colonized patients in order to reduce colonization pressure and their transmission.     

Infección nosocomial en el paciente receptor de un trasplante de órgano sólido o de precursores hematopoyéticos

Bacterial infections are the most common infections in solid organ transplant recipients. These infections occur mainly in the first month after transplantation and are hospital-acquired. Nosocomial infections cause significant morbidity and are the most common cause of mortality in this early period of transplantation. These infections are caused by multi-drug resistant (MDR) microorganisms, mainly Gram-negative enterobacteria, non-fermentative Gram-negative bacilli, enterococci, and staphylococci. The patients at risk of developing nosocomial bacterial infections are those previously colonized with MDR bacteria while on the transplant waiting list. Intravascular catheters, the urinary tract, the lungs, and surgical wounds are the most frequent sources of infection. Preventive measures are the same as those applied in non-immunocompromised, hospitalized patients except in patients at high risk for developing fungal infection. These patients need antifungal therapy during their hospitalization, and for preventing some bacterial infections in the early transplant period, patients need vaccinations on the waiting list according to the current recommendations. Although morbidity and mortality related to infectious diseases have decreased during the last few years in haematopoietic stem cell transplant recipients, they are still one of the most important complications in this population. Furthermore, as occurs in the general population, the incidence of nosocomial infections has increased during the different phases of transplantation. It is difficult to establish general preventive measures in these patients, as there are many risk factors conditioning these infections. Firstly, they undergo multiple antibiotic treatments and interventions; secondly, there is a wide variability in the degree of neutropenia and immunosuppression among patients, and finally they combine hospital and home stay during the transplant process. However, some simple measures could be implemented to improve the current situation.     

El laboratorio de Microbiología en la vigilancia y el control de las infecciones nosocomiales

The most relevant activities of clinical microbiologist and the laboratory in the surveillance and the control of nosocomial infections (NI) are mainly focused on the collection, analysis and management of the information obtained in the Microbiology Laboratory; the design, development and validation of microbiological techniques, particularly rapid tests for the early detection of nosocomial pathogens, especially those multi-drug resistant ones, and the study of the genetic relationship between them. It also assists in the design of specific programs for the prevention of the NI, and the evaluation of their impact, as well as taking part in educational and training programs on topics related to NI. The management of laboratory resources, and communications with hospital information systems is also important.     

Hipertensión arterial pulmonar en pacientes con infección por el virus de la inmunodeficiencia humana: situación actual

The increase in survival that has been achieved with the new treatments in the era of highly active antiretroviral therapy, has enabled clinicians and researchers to analyze issues that emerge in the long term in patients with HIV infection. Although the majority of cardiovascular complications have been widely described, the pathogenesis of pulmonary arterial hypertension is still poorly understood, and is one of the more complex and feared complications as it worsens the prognosis and quality of life of these patients