Prevalencia de infecciones de piel y tejidos blandos producidas por Staphylococcus aureus resistente a Meticilina Comunitario en Madrid

Introduction

Since it was first described in the 1990s, Methicillin-Resistant Staphylococcus aureus infection among people with no contact with a hospital setting or with no traditional risk factors, has spread worldwide and is now an important epidemiological and public health problem.

Methods

The present prospective and observational study was carried out from April to November 2010. All adult patients with community-acquired suppurative skin and soft tissue infection (SSTI) attending the Emergency Department were enrolled. Clinical, microbiological and epidemiological features of the infection were assessed.

Results

A total of 59 samples were collected from 59 patients and CA-MRSA was isolated in 13 of them. Prevalence of CA-MRSA in patients with suppurative SSTI seen in the emergency department was 22.03%, and was 33.3% in patients with staphylococcal infection. Is worth noting the greater presence of necrosis detected in CA-MRSA lesions. Only 3 patients required hospital admission. Eleven of the 13 strains were Panton-Valentine leucocidin producers, and 5 were resistant to non-betalactam antibiotics. CA MRSA infection is still more frequent in the immigrant population.

Conclusion

Data on CA-MRSA prevalence in Spain are sparse. This study aims to emphasise the current importance of this emergent pathogen in our area. About one third of suppurative staphylococcal SSTI presenting in our emergency department are caused by this agent, confirming a rapid spread in our country. Some clinical features, such as the high presence of necrosis, are closely related to CA-MRSA.     

Caracterización de cepas de Staphylococcus epidermidis y S. haemolyticus resistentes a meticilina y linezolid en un hospital español

Introduction

Linezolid resistance is mainly due to mutations in the 23S rRNA target. The aim of this study was to characterize linezolid and methicillin resistant Staphylococcus epidermidis (SE-LM^R) and S. haemolyticus (SH-LM^R) strains detected in a Spanish hospital.

Methods

SE-LM^R and SH-LM^R strains obtained in the period June 2009-August 2011 in a second level hospital were recorded along with the epidemiological characteristics of the patients. These strains were typed, and their resistance, phenotype, genotype and the factors determining their virulence were analysed.

Results

Linezolid resistance was explained by the presence of G2603T mutation (23S rRNA) and aminoacid changes in L3 and L4 ribosomal proteins. The 25 SE-LM^R strains belonged to sequence type ST2, presented SCCmec type III, and two different PFGE patterns. The two SH-LM^R strains showed non-typeable SCCmec. SE-LM^R strains harboured the resistance genes aac(6’)-aph(2”), and dfrS1. SH-LM^R strains contained these genes and the gene erm(C). No lincomycin resistance mechanism was identified in SE-LM^R strains regardless of showing lincomycin resistance and diminished susceptibility to clindamycin.

Conclusions

Linezolid resistance is of concern in hospitals, and requires continued vigilance. Several linezolid resistance mechanisms (mutation in 23S RNAr and amino acid changes in L3 and L4) were identified in this study.     

Infecciones de piel y partes blandas en pacientes hospitalizados: factores epidemiológicos,microbiológicos,clínicos y pronósticos

Introduction

Skin and soft-tissue infections (SSTIs) are a frequent cause of consultation in emergence services, and complicated cases require hospitalization. However there are few data in our setting about the clinical characteristics of these infections.

Material and methods

A retrospective review of hospital admitted patients with a diagnosis of folliculitis, cellulitis, erysipelas, abscesses, hidradenitis, furuncle, impetigo, fasciitis and Fournier's gangrene. Cases were extracted from the data base of diagnostic codes of the Archive and Clinical Documentation Department of Son Llàtzer Hospital from January 2002 to November 2011.

Results

We studied 996 episodes in 841 hospitalized patients with any diagnosis of SSTIs. Cellulitis/erysipelas (66.7%) was the most frequently diagnosed condition, with 77% of all SSTIs being community acquired, and the majority of patients had comorbidities, mainly diabetes (33%) and heart failure (17.7%). The most frequent isolated microorganism was S. aureus (35.1%), in 19 (12.9%) cases with methicillin-resistance (MRSA), 84.2% of them were nosocomial or health care acquired. Monotherapy with aminopenicillin with clavulanic acid was the empiric treatment most frequently used (35.5%). New antibiotics for Gram-positive cocci (linezolid, daptomycin, and tigecycline) were used in patients with comorbidities that presented more complications (P < .001) and more risk of mortality (P = .001). During admission 10.9% of patients died, but only in 2.7% of them mortality was related to the SSTIs.

Conclusions

SSTIs attended most frequently in hospitalized patients are mainly cellulitis/erysipela, the majority community acquired. MRSA infections are mainly health care related. Use of new antibiotic for Gram-positive cocci was limited.     

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 neonatales por Staphylococcus aureus de inicio en la comunidad

Introduction

Staphylococcus aureus is a major cause of neonatal community-onset infections. The emergence of methicillin-resistant S. aureus infections in this age group has been reported in USA in the last few years; however there are no studies in Spain. The aim of this study is to describe the epidemiological, clinical and microbiological characteristics of S. aureus community-onset infections in neonates.

Methods

We prospectively reviewed the S. aureus infections in neonates over a three year period (2007-2009) in the Pediatric Emergency Department of Hospital 12 de Octubre in Madrid (Spain).

Results

We recorded 30 cases of neonatal S. aureus community-onset infections. Only one isolated (3.3%) was resistant to methicillin, and two (6.7%) were PVL(+).

Conclusions

Despite the emergence of MRSA outside the hospital in pediatric population in Spain, CA-MRSA and SA PVL(+) infections are not frequent in neonates.     

Características clínicas y pronóstico de la neumonía adquirida en la comunidad causada por Staphylococcus aureus resistente a la meticilina

Introduction

The aim of this study is to describe the epidemiological and clinical features, treatment and prognosis of community-acquired pneumonia (CAP) caused by methicillin-resistant Staphylococcus aureus (MRSA) in two different geographic regions where community-acquired MRSA (CA-MRSA) infections have different frequencies.

Methods

Observational study of patients admitted to two hospitals (one in Argentina, the other in Spain) between March 2008 and June 2012.

Results

We documented 16 cases of CAP caused by MRSA. MRSA accounted for 15 of 547 (2.7%) cases of CAP in Hospital Rodolfo Rossi and 1 of 1258 (0,08%) cases at the Hospital Universitari de Bellvitge (P ≤ .001). Most patients were young and previously healthy. Multilobar infiltrates, cavitation and skin and soft tissue involvement were frequent. All patients had positive blood cultures. Five patients required admission to the intensive care unit. Early mortality (≤ 48 hours) was 19%, and overall mortality (≤ 30 days) was 25%.

Conclusion

CAP caused by MRSA causes high morbidity and mortality rates. It should be suspected in areas with a high prevalence of CA-MRSA infections, and especially in young and healthy patients who present with multilobar pneumonia with cavitation. Mortality is mainly related to septic shock and respiratory failure and occurs early in most cases.     

Staphylococcus aureus resistente a la meticilina y a descolonizadores habituales con reservorio en un trabajador sanitario en un hospital de tercer nivel

Background

Methicillin-resistant Staphylococcus aureus (MRSA) has become an important hospital-acquired pathogen, with transfer of the organism from a carrier or infected patient to uninfected patients by the hands or clothing of staff as the main mode of transmission.

Methods

Investigation of a cluster of new cases of MRSA resistant to mupirocin and fusidic acid, using epidemiological and microbiological resources.

Results

From September 2010 to February 2012, sixteen patients had at least one culture positive for MRSA resistant to mupirocin and fusidic acid. Some not apparently related cases and outbreaks appeared. By analysing cultures taken from patients and staff using pulsed-field gel electrophoresis, it was demonstrated that most likely this situation was started by an auxiliary nurse who was a carrier of the MRSA. Healthcare worker decontamination using oral antibiotic therapy was unsuccessful. Eventually, the situation was controlled by placing the carrier in a different job, with no further cases to date (September, 2012).

Conclusion

This report illustrates the risk of nosocomial transmission linked to care delivered by healthcare workers.     

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.     

Significado clínico del aislamiento de Staphylococcus aureus en muestras de orina

Introduction

To evaluate the clinical significance of the isolation of Staphylococcus aureus in urine samples.

Methods

A retrospective study was performed on adult patients identified from a microbiology database in a 200-bed general hospital between the years 2000 and 2009. The demographic data, comorbidities, and risk factors, were reviewed, particularly those associated with the concomitant isolation of S. aureus in blood cultures.

Results

The frequency of S. aureus found in urine samples was 0.63%. A total of 43 patients (mean age 68.7 years [SD ± 16], and 58.1% males) were identified in the database. A Charlson comorbidity index > 3 was observed in 20.9%. Concurrent bacteremia was seen in 48.8%. Two groups of patients were distinguished: with concomitant bacteremia (n = 21) or without (n = 22). Intervention in the urinary tract significantly predicted (P = .00004) bacteriuria without bacteremia (81.8%), compared to bacteremia cases (19%). The attributable mortality was 47.6% in patients with bacteremia compared to non-bacteremia (no deaths), even though the appropriate antibiotic treatment was more frequent among patients with bacteremia (92% and 60%, respectively).

Conclusion

The presence of S. aureus in urine was accompanied by bacteremia in half of the cases, but in patients without previous urinary tract intervention such a possibility increased to 81%. Concomitant bacteremia predicts a worse prognosis even with appropriate treatment.     

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.     

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.     

Estandarización de la técnica Dot-ELISA para la detección de anticuerpos anti-Trypanosoma cruzi y su comparación con ELISA y Western blot

Introduction

Chagas disease is considered endemic of Latin America. Because of migration of people from this region to non-endemic areas, such as the United States, Canada and Europe, it has become a major health problem. There are parasitology and serology tests for its diagnosis, but only the latter are useful during the chronic phase. Most of these tests require expensive equipment, which make them also inaccessible for laboratories in endemic areas. In the present work we standardize Dot-ELISA as a diagnostic test for Trypanosoma cruzi infection, since it is an easy, inexpensive and an accessible test.

Methods

A total of 360 samples were tested: 96 sera from Chagas patients and 153 from healthy people; 40 blood samples spots collected and eluted from filter paper were also tested, as well as 71 serum samples of patients with non-related infections. Sensitivity, specificity and kappa index of Dot-ELISA test were calculated, in order to determine a correlation value of this technique compared to ELISA and Western blot that are already being used for diagnosis.

Results

Dot-ELISA obtained 97% sensitivity and 89% specificity, since it showed cross-reaction mainly with Leishmania spp., and a kappa index of 0,79.

Conclusions

Dot-ELISA results correlate well with other tests that are already being used for diagnosis of Chagas disease. As it is easy and inexpensive, it may be useful as an additional diagnostic test or for field studies.     

Caracterización molecular de aislados humanos de Cryptosporidium spp. procedentes de 2 diferentes localizaciones de España

Molecular PCR based diagnostic techniques have enabled us to distinguish between the different, morphologically identical, Cryptosporidium species that can infect humans. Of the 23 recognized species in the genus, at least 9 are able to infect humans. As the intensity of the clinical manifestations, pathogenicity, excretion of oocysts, and incidence, are different between this species, molecular studies are crucial for a better understanding of the epidemiology of human cryptosporidiosis.     

Prevalencia del determinante de resistencia plasmídica a quinolonas aac(6’)-Ib-cr en cepas de Escherichia coli y Klebsiella pneumoniae productoras de BLEE aisladas en diez hospitales de Chile

Introduction

The frequency of aac(6′)-Ib-cr gene in ESBL-producing strains of Klebsiella pneumoniae and Escherichia coli is unknown, in Chile.

Methodology

The aac(6′)-Ib and aac(6’)-Ib-cr genes were investigated using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), and sequencing, in strains isolated from 10 Chilean hospitals between 2008-2009.

Results

The aac(6’)-Ib-cr gene was detected in 54% of K. pneumoniae and 74% of E. coli strains. The CIM₅₀ of CIP was higher among strains harboring aac(6’)-Ib-cr, 8 times higher in K. pneumoniae and 4 times higher in E. coli. Moreover, both aac(6’)-Ib and aac(6’)-Ib-cr were simultaneously found in 13 K. pneumoniae and 3 E. coli isolates.

Conclusion

This is the first report of aac(6’)-Ib-cr in ESBL-producing strains of K. pneumoniae and E. coli isolated from in-patients in Chilean hospitals located along an area of more than 2,800 Km.     

Resistencia a antibióticos y factores de virulencia en aislados clínicos de Salmonella enterica

Introduction

The increase of Salmonella enterica isolates multi-resistant to different antibiotics, including β-lactams and fluoroquinolones, is a problem of clinical importance. The dissemination of Salmonella Typhimurium resistant to ampicillin (AMP)-chloramphenicol (CHL)-streptomycin (STR)-sulphonamides and (SUL)-tetracycline (TET), that harbour the Salmonella Genomic Island type 1 (SGI1), and the acquisition of transferable genetic material have favoured the multi-resistance in this genus.

Methods

A total of 114 clinical S. enterica isolates were studied (period 2009-2010). The susceptibility to 20 antibiotics was determined by disc diffusion and microdilution. The antimicrobial resistance mechanisms and the integrons were analysed by PCR, and sequencing in the AMP^R isolates. In all the bla_PSE-1-positive isolates, the clonal relationship was determined by PFGE, as well as the presence of SGI1 and 29 virulence genes by PCR.

Results

Eighteen different serotypes were found among the 114 isolates studied, Typhimurium (61%) and Enteritidis (16%) being the most prevalent. High percentages of resistance to SUL (68%), TET (58%), AMP (55%) and STR (46%) were observed. The great majority (92%) of 63 AMP^R isolates were multi-resistant, with the AMP-STR-TET-SUL phenotype (19 isolates) being the most frequent one and associated with the bla_TEM-1b + strA-strB + tet(B) + sul2 genotype. Class 1 integrons (7 different structures) were observed in 48% AMP^R isolates, highlighting the bla_OXA-1 + aadA1 structure (8 isolates), one empty integron and non-classical integrons (5 isolates). The bla_PSE-1 gene was detected inside the classical SGI1 structure in 13 clonally-related isolates that showed the same virulence profile.

Conclusions

The high percentage of multi-resistant S. enterica isolates, especially associated to S. Typhimurium, to the AMP, STR, TET and SUL phenotype, and to the bla_TEM-1b + strA-strB + tet(B) + sul2 genotype, shows an important risk of possible failures in the treatment of serious infections caused by this serotype.