Streptococcus spp. isolated from bovine mastitis: Antimicrobial sensitivity studies and disagreement evaluation between routine phenotypic diagnosis and molecular identification.

Bovine mastitis poses a significant threat to global dairy production, resulting in substantial losses in milk production. Streptococcus bacteria, particularly Streptococcus uberis, Streptococcus agalactiae, and Streptococcus dysgalactiae, are commonly implicated in this condition. An accurate diagnosis is crucial for implementing effective treatment and minimizing its impact on production. This study examined 115 Streptococcus strains isolated from bovine mastitis cases in Uruguay using PCR for species identification. Additionally, the resistance to tetracycline, erythromycin, and penicillin was assessed in 81 of the bacterial strains under study. Significant disparities between phenotypic and genotypic detection were evident across all three species, with only 31% of strains identified phenotypically aligning with PCR results. Phenotypic prevalence indicated S. dysgalactiae as the most prevalent (44.35%), followed by S. uberis (24.34%) and S. agalactiae (6.09%). However, the genotypic identification revealed S. uberis as the most prevalent, followed by S. dysgalactiae, while S. agalactiae remained the least prevalent. The high sensitivity and speed of PCR suggest its potential routine implementation for diagnosing bovine mastitis caused by Streptococcus in any laboratory. Although, penicillin resistance was practically nonexistent, tetracycline and erythromycin exhibit higher resistance levels across all three species studied. In conclusion, the study underlines the importance of early diagnosis, highlights variations in bacterial prevalence, and proposes PCR as a valuable diagnostic tool for Streptococcus species responsible for bovine mastitis.

Anaerobic digestates in agricultural soils: A systematic review of their effects on antibiotic resistance genes.

Tackling the dissemination of antibiotic resistance is one of the main global challenges. Manures from animal production are a recognized source of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) requiring appropriate treatment methods. One of the main approaches for manure treatment is anaerobic digestion (AD). Meta-analyses have demonstrated that AD can significantly reduce the load of ARGs. However, antibiotics, ARGs and MGEs still remain in the final product (digestate). A sustainable agricultural use of digestates under the One Health framework requires wide assessments of their effects in the soil resistome. The objective of this review was to present the state of the art of digestate effects on ARGs of agricultural soils, focusing exclusively on digestates from animal manures. A systematic review was conducted. The examination of the resulting literature indicated that although temporal decays are observed for a variety of ARGs in single-application and repeated-applications experiments, for certain ARGs the pre-treatment or control levels are not restored. However, the low number of studies and the heterogeneous experimental conditions preclude a clear understanding of the fate of ARGs in soil and their risk for agroecosystems. The inclusion of multiple MGEs and the assessment of the long-term influence of digestates on soil properties and microbial communities could be keystones for a better understanding of the risks associated with digestate-induced changes in the soil resistome.

Characterization and antimicrobial susceptibility of coagulase-positive Staphylococcus isolated in a veterinary teaching hospital in Chile.

There is limited information about the prevalence and antimicrobial susceptibility of coagulase-positive Staphylococcus (CoPS) strains in veterinary settings in Chile. The aim of this observational study was to identify and characterize CoPS strains from dogs, owners, veterinary professionals and surfaces in a veterinary teaching hospital at Universidad de Chile to determine the presence of methicillin-resistant strains and evaluate the genetic relationship among the strains. Veterinarians (n=24), surfaces (n=10), and healthy dogs (n=40) and their respective owners (n=40) were sampled for CoPS. Isolates were identified by PCR and antimicrobial susceptibility was assessed by the disk diffusion method and MIC. The presence of the mecA gene was evaluated by PCR, and the genetic relationship among the strains was established by PFGE. A total of 45 CoPS strains were obtained, eight from veterinary professionals, three from hospital surfaces, eight from owners and 26 from dogs. Nine of the strains were resistant to methicillin (20%), and all of them carried the mecA gene. A high percentage of the strains was resistant to clindamycin (33.3%). Additionally, the isolated CoPS showed high genetic diversity. This study suggests that veterinarians are in high risk of harboring methicillin-resistant CoPS (25% versus 2.5% from owners) and our results provide evidence that clindamycin could not be an empiric alternative for CoPS in the analyzed hospital. This is the first report of methicillin-resistant CoPS in veterinary settings in Chile, considering humans, pets and surfaces.

Estrategias de protección antimicrobiana en el cuidado de heridas: evidencia para el uso de apósitos recubiertos con DACC.

BACKGROUND: Antimicrobial resistance (AMR) is one of the most serious health threats globally. The development of new antimicrobials is not keeping pace with the evolution of resistant microorganisms, and novel ways of tackling this problem are required. One of such initiatives has been the development of antimicrobial stewardship programmes (AMS). The use of wound dressings that employ a physical sequestration and retention approach to reduce bacterial burden offers a novel approach to support AMS. Bacterial-binding by dressings and their physical removal can minimise their damage and prevent the release of harmful endotoxins. OBJECTIVE: To highlight AMS to promote the correct use of antimicrobials and to investigate how dialkylcarbamyl chloride (DACC)-coated dressings can support AMS. METHOD: MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar were searched to identify articles relating to AMS, and the use of wound dressings in the prevention and treatment of wound infections. The evidence supporting alternative wound dressings that can reduce bioburden and prevent wound infection in a way that does not kill or damage the microorganisms were reviewed. RESULTS: The evidence demonstrated that using bacterial-binding wound dressings that act in a physical manner (eg, DACC-coated dressings) to preventing infection in both acute and hard-to-heal wounds does not exacerbate AMR and supports AMS. CONCLUSION: Some wound dressings work via a mechanism that promotes the binding and physical sequestration and removal of intact microorganisms from the wound bed (eg, a wound dressing that uses DACC technology to prevent/reduce infection). They provide a valuable tool that aligns with the requirements of AMS by effectively reducing wound bioburden without inducing/selecting for resistant bacteria.

ANTECEDENTES: Normalmente, las infecciones son tratadas con antimicrobianos (antibióticos, antisépticos, etc.). La resistencia antimicrobiana (AMR, por sus siglas en inglés) se ha convertido en una de las amenazas del siglo XXI más graves para la salud mundial. Las heridas pueden ser una fuente de infección al permitir la entrada libre de microorganismos dentro del cuerpo, incluyendo bacterias resistentes a antimicrobianos. El desarrollo de nuevos antimicrobianos (especialmente, antibióticos) no está siguiendo el ritmo de la evolución de microorganismos resistentes y de formas novedosas de abordar este problema con la urgencia que demanda. Una de estas iniciativas ha sido el desarrollo de programas de protección antimicrobiana (AMS, por sus siglas en inglés), que brindan capacitación a los trabajadores del área de la salud y controlan la prescripción, enfocándose en los antimicrobianos para reducir la probabilidad de que se produzca AMR. El uso de apósitos para herida que utilizan el aislamiento físico y el abordaje de retención, en vez de agentes antimicrobianos, para reducir la carga bacteriana ofrecen un abordaje novedoso para apoyar a los AMS. La fijación bacteriana por los apósitos y su retiro físico, en lugar de la muerte activa, minimiza su daño y, además, previene la liberación de endotoxinas dañinas. OBJETIVO: Resaltar los AMS para la promoción del uso correcto de antimicrobianos e investigar cómo los apósitos recubiertos con cloruro de dialquilcarbamilo (DACC) pueden ayudar a cubrir las metas de los AMS. MÉTODO: Se realizaron búsquedas en las bases de datos de revisiones sistemáticas, Medline, Cochrane y Google Scholar con el fin de identificar artículos publicados que describan los datos relacionados con los AMS, y el uso de una gran variedad de apósitos para heridas para la prevención y/o tratamiento de infecciones de la herida. La evidencia que respalda a los apósitos para heridas alternativos que pueden reducir la biocarga y prevenir y/o tratar la infección de heridas de forma tal que no maten ni dañen a los microorganismos (por ejemplo, fijándose activamente y retirando intactos a los microorganismos de las heridas) fue posteriormente revisada de forma oral. CONCLUSIÓN: Algunos apósitos para heridas actúan a través de mecanismos que promueven la fijación y absorción física, aislamiento y retiro de microorganismos intactos de la base de la herida (por ejemplo, un apósito para heridas que utiliza la tecnología DACC para prevenir/reducir la infección). Esta es una herramienta valiosa que cumple con los requisitos del AMS (por ejemplo, reducción del uso de antimicrobianos en esquemas de tratamiento de heridas) al reducir la biocarga de la herida sin inducir/seleccionar bacterias resistentes.

Virulence genes and antimicrobial susceptibility in Salmonellaenterica serotypes isolated from swine production in Argentina.

Salmonella is a worldwide-distributed pathogen that affects both humans and animals and is usually associated with intensive animal production such as poultry and swine. This bacterium carries different virulence genes, whose expression favors its interaction with the host and may influence the course of the infection. Extended usage of antibiotics for metaphylaxis or prophylaxis and as growth promoters favors the emergence of multiresistant Salmonella strains. The aim of this work was to assess the association between the presence of virulence-associated genes and the antimicrobial resistance phenotype in Salmonella isolates obtained from swine intensive and backyard farms in Argentina during 2012-2018. A total of 59 Salmonella strains belonging to several serotypes were studied. All the strains carried the sopB and ssaQ genes, whereas more than 90% of the isolates carried the mgtC, avrA, and siiD genes. Some isolates also carried the bcfC, sodC1, gipA, sopE1 and spvC genes; however, their presence varied among them. Susceptibility to the antibiotics tested was diverse. Isolates from intensive farms were resistant to a larger number of antimicrobials than those from backyard farms and some of the strains showed high virulence potential and extensive antimicrobial resistance profiles. Continuous surveillance is essential to detect the emergence of strains that may represent a significant risk not only for animal production but also for the human population.

Antimicrobial resistance. Its importance and efforts to control it.

The World Health Organization estimates that bacterial resistance will cause 10 million deaths by 2050. As part of the Global Action Plan on Antimicrobial Resistance, it proposed networks of specialized laboratories in order to preserve strains and optimize the use of antimicrobials. That is the case of the Latin American Surveillance Network of Antimicrobials Resistance. In a 2019 study, the main bacteria of the ESKAPE group (which are highly resistant to the most widely used antibiotics) that cause infections in Mexican Hospitals were identified to be multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL)-producing Klebsiella spp., ESBL-producing Enterobacter spp., Acinetobacter baumannii, MDR Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. With information on drug resistance, regimens are recommended to treat infection caused by Helicobacter pylori, a pathogen related to the development of cancer and whose prevalence in the adult population of Latin America is estimated to range between 60 and 70 %.

La Organización Mundial de la Salud estima que en 2050 la resistencia bacteriana ocasionará 10 millones de muertes. Como parte del Plan de Acción Mundial sobre la Resistencia a los Antimicrobianos propuso redes de laboratorios especializados, para conservar cepas y optimizar el uso de los antimicrobianos. En un estudio de 2019 se identificó que las principales bacterias del grupo ESKAPE (con alta resistencia a los antibióticos más usados) que causan infecciones en hospitales de México son Klebsiella spp. resistentes a múltiples fármacos (MDR) y productoras de betalactamasa de espectro extendido (BLEE), Enterobacter spp. BLEE, Acinetobacter baumannii, Pseudomonas aeruginosa MDR, Staphylococcus aureus meticilinorresistente y Enterococcus faecium resistente a vancomicina. Con la información de resistencia a los fármacos se recomiendan esquemas para tratar la infección causada por Helicobacter pylori, relacionado con el desarrollo de cáncer y cuya prevalencia en la población adulta de Latinoamérica se estima es de entre 60 y 70 %.

Clinical and microbiological characteristics of community-acquired pneumonia associated with Streptococcus pneumoniae in adult patients in Mexico.

The aim of this study was to assess the risk factors and clinical and microbiological characteristics of community-acquired pneumonia (CAP) in adult patients in Mexico. Streptococcus pneumoniae classified as the causative agent of CAP in adult patients and patients with invasive S. pneumoniae isolates presented to three tertiary teaching hospitals during the 15-year study period were selected. Serotyping and susceptibility testing were performed for all included isolates. Clinical and demographic data were recorded. A total of 96 patients infected with S. pneumoniae (71 with CAP, 25 with invasive disease) were included. The CAP group involved more males (74.6%) than the invasive disease group (p=0.03). Head trauma was more common in the CAP group (21.1%) than in the invasive disease group (4.0%; p=0.03). The most prevalent serotype was 19A, followed by serotypes 3 and 23F. After the introduction of the heptavalent conjugated pneumococcal vaccine (PCV7), the prevalence of included serotypes declined significantly; no such change was found after the introduction of the PCV13 vaccine, including in the prevalence of serotype 19A. Susceptibility to all antimicrobials tested except vancomycin declined over the study period. In conclusion, head trauma was the most common comorbidity in the CAP group. The most prevalent serotype was 19A. Decreased susceptibility to most antimicrobials tested was observed.

[Antibiotic susceptibility of Staphylococcus aureus and Streptococcus pneumoniae in healthy carrier individuals in primary care in Barcelona area]. / Sensibilidad antibiótica de Staphylococcus aureus y Streptococcus pneumoniae en personas portadoras nasales sanas en atención primaria en el área de Barcelona.

INTRODUCTION: The information available on antibiotic resistance patterns are generally based on specimens from hospitalised individuals. This study was aimed at evaluating the antibiotic resistance rate of nasal carriage strains of Staphylococcus aureus and Streptococcus pneumoniae in healthy individuals, in accordance with age and gender, attended in Primary Care Centres (PCC). DESIGN: Cross-sectional study. SETTING: Seven PCC in the Barcelona area. PARTICIPANTS: Healthy nasal carriers aged 4years or more who did not present with any sign of infectious disease, and had not taken any antibiotic or had been hospitalised in the previous 3months. MAIN MEASUREMENTS: A total of 3,969 nasal swabs valid for identification were collected between 2010 and 2011 and were sent to one central microbiological laboratory for isolation of both pathogens. Resistance to common antibiotics was determined on the basis of the current European Committee on Antimicrobial Susceptibility Testing guidelines on cut-off points. RESULTS: The prevalence of methicillin-resistant S.aureus was 1.3% (95%CI: 0.5-2.1%), with resistance rates of 87.1% to phenoxymethylpenicillin and 11.6% to azithromycin, with no significant differences with age and gender. A total of 2.4% (95CI%: 0.1-4.7%) of the pneumococcal strains were highly resistant to both phenoxymethylpenicillin and macrolides, whereas the highest resistance rates were to cefaclor (53.3%), followed by tetracycline (20%) and cefuroxime (12.1%). CONCLUSIONS: These pathogens have lower resistance rates in the community than in the hospital setting. Primary Care physicians must be more aware of the current antimicrobial resistance, in order to ensure prudent use of antibiotics.

Patterns of infections, aetiological agents and antimicrobial resistance at a tertiary care hospital in northern Tanzania.

OBJECTIVE: To determine the causative agents of infections and their antimicrobial susceptibility at a tertiary care hospital in Moshi, Tanzania, to guide optimal treatment. METHODS: A total of 590 specimens (stool (56), sputum (122), blood (126) and wound swabs (286)) were collected from 575 patients admitted in the medical and surgical departments. The bacterial species were determined by conventional methods, and disc diffusion was used to determine the antimicrobial susceptibility pattern of the bacterial isolates. RESULTS: A total of 249 (42.2%) specimens were culture-positive yielding a total of 377 isolates. A wide range of bacteria was isolated, the most predominant being Gram-negative bacteria: Proteus spp. (n = 48, 12.7%), Escherichia coli (n = 44, 11.7%), Pseudomonas spp. (n = 40, 10.6%) and Klebsiella spp (n = 38, 10.1%). Wound infections were characterised by multiple isolates (n = 293, 77.7%), with the most frequent being Proteus spp. (n = 44, 15%), Pseudomonas (n = 37, 12.6%), Staphylococcus (n = 29, 9.9%) and Klebsiella spp. (n = 28, 9.6%). All Staphylococcus aureus tested were resistant to penicillin (n = 22, 100%) and susceptible to vancomycin. Significant resistance to cephalosporins such as cefazolin (n = 62, 72.9%), ceftriaxone (n = 44, 51.8%) and ceftazidime (n = 40, 37.4%) was observed in Gram-negative bacteria, as well as resistance to cefoxitin (n = 6, 27.3%) in S. aureus. CONCLUSION: The study has revealed a wide range of causative agents, with an alarming rate of resistance to the commonly used antimicrobial agents. Furthermore, the bacterial spectrum differs from those often observed in high-income countries. This highlights the imperative of regular generation of data on aetiological agents and their antimicrobial susceptibility patterns especially in infectious disease endemic settings. The key steps would be to ensure the diagnostic capacity at a sufficient number of sites and implement structures to routinely exchange, compare, analyse and report data. Sentinel sites (hospitals) across the country (and region) should report on a representative subset of bacterial species and their susceptibility to drugs at least annually. A central organising body should collate the data and report to relevant national and international stakeholders.

[Antimicrobial resistance and molecular epidemiology of Staphylococcus pseudintermedius strains isolated from dog clinical samples]. / Resistencia antimicrobiana y epidemiología molecular de aislamientos de Staphylococcus pseudintermedius de muestras clínicas de caninos.

Twenty-eight strains isolated from dog clinical samples identified as Staphylococcus pseudintermedius by mass spectrometry (MALDI-TOF) were studied to assess antimicrobial susceptibility by the diffusion method and clonal relationship by pulsed field gel electrophoresis (PFGE). Methicillin resistance (3/28 isolates; 10,7%) was evaluated by mecA PCR. Fifteen strains (53.6%) were resistant to at least one of the antibiotics tested, and eleven of them (39.3%) showed multiple resistance (3 or more antimicrobial families). Eleven isolates (39.3%) were resistant to erythromycin due to the presence of ribosomal methylase ermB, whereas clindamycin inducible resistance was not detected. Twenty-seven (27) clonal types were differentiated by PFGE, suggesting high clonal diversity. We emphasize that the finding of multiresistant S. psedintermedius strains is an emerging problem to be considered in veterinary diagnostic laboratory treatment of canine infections and in public health settings.

Carbapenemase-producing Enterobacteriaceae: the end of the antibiotic era?

Infections produced by carbapenemase-producing Enterobacteriaceae (CPE) are increasing worldwide. Therapeutic options are scarce because many of these bacteria are resistant to other antimicrobial groups. Furthermore, the dissemination of some carbapenemases and CPE is occurring rapidly. Health care authorities should be aware of the relevance of this problem, and coordinated surveillance and control strategies at all levels of the health system should be undertaken. The Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC) and The Spanish Network for Research on Infectious Diseases (REIPI, Institute of Health Carlos III, Ministry of Health, Spain) has selected a panel of Spanish experts on infections caused by CPE from the areas of clinical microbiology, infectious diseases and public health to review and discuss the most controversial issues regarding this increasing threat.

[Importance of quality control for the detection of ß-lactam antibiotic resistance in Enterobacteriaceae]. / Importancia de los controles de calidad para la detección de la resistencia a antibióticos ß-lactámicos en enterobacterias.

ß-lactam antimicrobial agents are frequently used to treat infections caused by Enterobacteriaceae. The main mechanism of resistance to these antibiotics is the production of certain enzymes, collectively named ß-lactamases. Due to their substrate profile and their epidemiological implications, the most clinically important ß-lactamases are extended-spectrum ß-lactamases, class C ß-lactamases and carbapenemases. Phenotypic detection of these enzymes may be complicated and is based on the use of specific inhibitors of each ß-lactamase and on the loss of activity on some ß-lactam indicators. Various international committees postulate that it is no longer necessary to interpret the susceptibility results or determine the mechanism of resistance. Several critics disagree, however, and consider that susceptibility results should be interpreted until more data are available on the clinical efficacy of treatment with ß-lactams. Given these methodological difficulties and constant changes in the interpretation criteria, we consider that training and external quality controls are essential to keep updated in this field. For learning purposes, these external quality controls should always be accompanied by a review of the results and methodology used, and the analysis of errors. In this paper we review and contextualize all the aspects related to the detection and interpretation of these ß-lactamases.

[Preventive measures for avoiding transmission of microorganisms between hospitalised patients. Hand hygiene]. / Medidas de prevención de la transmisión de microorganismos entre pacientes hospitalizados. Higiene de manos.

Health-care associated infections are an important public health problem worldwide. The rates of health-care associated infections are indicators of the quality of health care. The infection control activities related to prevention of transmission of hospital microorganisms can be grouped in 4 mayor areas: standard precautions, specific precautions (including isolation if appropriate), environmental cleaning and disinfection, and surveillance activities (including providing infection rates and monitoring procedures). Hand hygiene and the correct use of gloves are the most important measures to prevent health-care associated infections and to avoid the dissemination of multidrug-resistant microorganisms. Continuous educational activities aimed at improving adherence to hand hygiene are needed. Periodical assessment of adherence to hand hygiene recommendations with feed-back have been shown to provide sustained improvement. Several complementary activities are being evaluated, including skin decolonization prior to certain surgeries, a package of measures in patients with central venous catheters or mechanical ventilation, and universal body hygiene with chlorhexidine. The present area of discussion concerns in which situations and in which groups would such measures be effective and efficient.

Empiric treatment vs susceptibility-guided treatment for eradicating H. pylori: Is it possible to change that paradigm using modern molecular methods?

Helicobacter pylori (H. pylori) infection is the most widespread infectious-contagious disease worldwide, reaching a prevalence of 50-80% in developing countries. Chronic infection is considered the main cause of chronic gastritis and has been related to other diseases, such as peptic ulcer, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. The most common treatment is with eradication regimens that utilize three or four drugs, including a proton pump inhibitor (PPI) and the antibiotics, clarithromycin and amoxycillin or metronidazole. Empiric antibiotic use for eradicating the bacterium has led to a growing resistance to those drugs, reducing regimen efficacy and increasing costs for both the patient and the healthcare sector. In such a context, the development of noninvasive next-generation molecular methods holds the promise of revolutionizing the treatment of H. pylori. The genotypic and phenotypic detection of the resistance of the bacterium to antibiotics enables personalized treatment regimens to be provided, reducing costs and implementing an antibiotic stewardship program. The aims of the present narrative review were to analyze and compare the traditional and next-generation methods for diagnosing H. pylori, explain the different factors associated with eradication failure, and emphasize the impact of the increasing antibiotic resistance on the reversal and prevention of H. pylori-associated diseases.

Prevalence and impact of antimicrobial resistance in gastrointestinal infections: A review.

Antimicrobial resistance has become a worldwide problem due to its excessive increase in recent years. The aim of the present review was to bring together data from different articles describing the levels of antimicrobial resistance in the most common gastrointestinal infections reported across the globe. The literature search was carried out in Google Scholar, Medline, Embase, and Pubmed, with the terms "antimicrobial resistance", "resistance in gastrointestinal disorders", and "resistance in amoebiasis", in Spanish and English. Mexican treatment guidelines and consensuses from 2017 to the present were utilized. Publications from the last ten years were chosen to describe the level of resistance. They had adequate sample sizes, the Material and Methods sections were precise, and they included multicenter studies, national and international consensuses, meta-analyses, systematic reviews, and extensive texts. The final number of articles was 51. The microorganisms that demonstrated the highest percentage of resistance were Helicobacter pylori (metronidazole 50%-80%, clarithromycin 20%-40%, and levofloxacin 30%-35%), Clostridioides difficile (clindamycin 8.3%-100%, cephalosporines 51%), Campylobacter jejuni and Campylobacter coli (fluoroquinolones 85%), Escherichia coli (ampicillin 76.5%), Entamoeba histolytica (metronidazole 50%), and bacterial peritonitis (third-generation cephalosporines 40%, methicillin 85%). Antimicrobial resistance is reaching elevated percentages, making it necessary to evaluate the situation of each patient, to successfully treat gastrointestinal infections.

[Analysis of the predictive value of preventive isolation criteria in the intensive care unit]. / Análisis del valor predictivo de los criterios de aislamiento preventivo en una unidad de cuidados intensivos.

OBJECTIVE: To assess the diagnostic accuracy of the criteria used to detect patients carrying multiresistant microorganisms (MRMs). DESIGN: A prospective observational study was carried out from May 2014 to May 2015. SETTING: Polyvalent Intensive Care Unit. PATIENTS: A cohort of consecutively admitted patients meeting the following criteria for preventive isolation according to the "Zero Resistance" project: hospital length of stay>4 days in the last three months ("hospital"); antibiotherapy during one week in the last month ("antibiotic"); institutionalized patients or recurrent contact with healthcare ("institution or care"); MRM carrier in the last 6 months ("previous MRM"). VARIABLES: Demographic data, culture results and isolation time. A multivariate analysis was performed using multiple logistic regression between each of the risk factors and patient MRM carrier status. RESULTS: During the study period, 575 patients were admitted, of which 28% met the isolation criteria (162). Fifty-one (31%) were MRM carriers. Of the patients who did not meet the criteria, 29 (7%) were carriers. In the multivariate analysis, the only variable independently associated to carrier status was "previous MRM", with OR=12.14 (95%CI 4.24-34.77). CONCLUSIONS: The only criterion independently associated with the ability to detect patients with MRMs upon admission to the ICU was the existence of "previous MRM".

[Etiological profile and antimicrobial sensitivity in 1740 urinary infections of the community in the city of Córdoba, Argentina.] / Perfil etiológico y sensibilidad antimicrobiana en 1740 infecciones urinarias de la comunidad en la ciudad de Córdoba, Argentina.

INTRODUCTION: Urinary tract infections (Uti) are one of the most common infections that affec thumans throughout their lives and are a common healthproblem both at the community and at the nosocomial level. Knowing microbiological characteristics, sensitivity profile and risk factors allow to optimize the management of Utis minimizing the increase of antibiotic resistance (AR) and establishing early treatments to reduce the morbidity and severity of infection. This study aims to establish which microorganisms are responsible for urinary tract infections in our community and determine their AR. PATIENTS AND METHODS: An observational, descriptive, cross-sectional, retrospective study of all patients with the first episode of UTI recorded at the Sanatorio Allende in the city of Cordoba, Argentina, who were requested to under go urine culture (URC), from January 2016 to December 2017. RESULTS: 3636 positive URC were analyzed, of which1740 met the inclusion criteria. Of the total analyzed 90.2 % (n=1570) were female. The average age was 37.8 years (SD=15.2). Escherichia coli was the microorganism most frequently isolated in 80.3% followed by S. saprophyticus in 8.0%. The age group of 18-30 years (40.1%) showed the highest proportion of microorganisms, where we observed the highest prevalence of E. coli and S. saprophyticus. The following acquired resistances were obtained from the total isolations: 47.6% of the microorganisms were resistant to ampicillin, 29.6% to cotrimoxazole, 15.2% to ciprofloxacin, 4.6% to first generation of cephalosporins, 3.4% to cefixime, 2.3% to amoxicillin-clavulanic, 1,2% to gentamicin and 1% to nitrofurantoin. CONCLUSION: E. Coli was the most prevalent pathogenin our environment, with high rates of resistance to ampicillin, fluoroquinolones and trimethoprim-sulfamethoxazole, confirming the need for periodic studiesto determine the most optimal empirical antibiotic treatment.

INTRODUCCIÓN: Las infecciones del tracto urinario (ITU) son una de las infecciones más comunes que afectan al ser humano a lo largo de su vida y constituyen un problema de salud frecuente tanto en el ámbito comunitario como nosocomial. El conocimiento de las características microbiológicas, perfil de sensibilidad y factores de riesgo permiten optimizar el manejo de las ITU minimizando el incremento de resistencia antibiótica (RA), estableciendo tratamientos precoces para reducir la morbilidad y la gravedad de la infección. Este estudio tiene como objetivo establecer cuáles son los microorganismos responsables de las infecciones urinarias de la comunidad en nuestro medio y determinar su RA.PACIENTES Y MÉTODOS: Estudio observacional, descriptivo, transversal, retrospectivo de todos los pacientes con primer episodio de ITU registrado en el Sanatorio Allende de la ciudad de Córdoba, Argentina a los cuales se les solicitó urocultivo (URC), desde enero de 2016 a diciembre 2017.RESULTADOS: Se analizaron 3636 URC positivos de los cuales 1740 cumplieron con los criterios de inclusión. Del total analizado 90,2% (n=1570) fueron de sexo femenino. El promedio de edad fue 37,8 años (DE=15,2).Escherichia coli fue el microorganismo aislado en mayor frecuencia en un 80,3% seguido de S. saprophyticus en un 8,0 %. El grupo etario de 18-30 años (40,1%) demostró la mayor proporción de microorganismos, en donde observamos mayor prevalencia de E. coli y S. saprophyticus. Del total de aislamientos se obtuvieron las siguientes resistencias adquiridas: 47,6% de los microorganismos fueron resistentes a ampicilina, 29,6% a cotrimoxazol, 15,2% a ciprofloxacina, 4,6% a cefalosporinas de 1° generación, 3,4% a cefixima, 2,3% a amoxicilina-clavulánico, 1,2% a gentamicina y 1% anitrofurantoína.CONCLUSIÓN: E. Coli fue el patógeno más frecuente en nuestro entorno, con altas tasas de resistencia a ampicilina, fluoroquinolonas y TMS, confirmando la necesidad de estudios periódicos para determinar el tratamiento antibiótico empírico más óptimo.

Evolution of the antimicrobial resistance rates in clinical isolates of Pseudomonas aeruginosa causing invasive infections in the south of Spain. / Evolución de la resistencia antimicrobiana en aislados clínicos de Pseudomonas aeruginosa productores de infecciones invasivas en el sur de España.

INTRODUCTION: The aim of this study was to determine the antimicrobial resistance rates and their evolution in clinical isolates of Pseudomonas aeruginosa causing invasive infections in the south of Spain between 2012 and 2017. METHODS: Retrospective study consisting of the collection of microbiological data from 20 hospitals (14 from Andalucía, 5 from Extremadura and 1 from Ceuta) between 2012 and 2017. The main variables studied were the antimicrobial susceptibility testing system used, interpretation criteria (CLSI or EUCAST) and the rate or percentage of resistant isolates. RESULTS: The most widely used antimicrobial susceptibility testing system was MicroScan (58%). The global resistance rates varied between 25% (ciprofloxacin) and 4% (colistin) using EUCAST, and between 19% (ciprofloxacin and imipenem) and 3% (amikacin) using CLSI. The antimicrobial resistance rates were relatively stable throughout the period 2012-2017. 14% of isolates were MDR and 7% were XDR. Respiratory isolates were more resistant, particularly to ciprofloxacin and colistin, than isolates from urine or blood. CONCLUSIONS: The antimicrobial resistance rates in P. aeruginosa are not particularly high in the south of Spain. The highest resistance rates were observed with ciprofloxacin, piperacillin/tazobactam and meropenem, whereas the more active antimicrobials were colistin, tobramycin and amikacin. The highest resistance rates were seen in respiratory isolates. In general, the resistance rates remained stable during the study period for most of the antimicrobials studied.

Microbiology of Hafnia alvei. / Microbiología de Hafnia alvei.

Hafnia alvei is a Gram-negative facultatively anaerobic bacillus that constitutes part of the human gut flora. Until recently, H. alvei strains could be mistakenly identified by conventional methods, miniaturisation or automatic systems as members of the Serratia, Escherichia, Citrobacter, Yokenella, Obesumbacterium or Salmonella genera. Consequently, molecular techniques were required for their definitive identification in the clinical laboratory. In addition, a new Hafnia species, H. paralvei, has recently appeared, which undoubtedly includes many of the strains reported in the literature as H. alvei. Alrhough H. alvei isolation from human clinical specimens remains uncommon, the development of drug resistance due to this species is emerging and it is likely that this organism will gain increasing importance in the future. Moreover, although H. alvei shares some virulence mechanisms with other Gram-negative enteropathogens, little is known about the factors that contribute to its pathogenesis in humans. The present article reviews the current identification methods, antimicrobial resistance and virulence factors of this bacterium.

Pharmacokinetic/pharmacodynamic analysis as a tool for surveillance of the activity of antimicrobials against Pseudomonas aeruginosa strains isolated in critically ill patients.

INTRODUCTION: To evaluate the changes in the susceptibility of Pseudomonas aeruginosa over time (2000-2017) against antimicrobials used in an intensive care unit of a Spanish tertiary hospital, and to compare them with the antimicrobial activity considering theoretical pharmacokinetic/pharmacodynamic (PK/PD) criteria. The influence of the method for handling duplicate isolates to quantify susceptibility rates was also evaluated. METHODS: The susceptibility was studied considering the Clinical and Laboratory Standards Institute (CLSI) breakpoints. Monte Carlo simulations were conducted to calculate the cumulative fraction of response (CFR). Linear regression analysis was applied to determine the trends in susceptibility and in the CFR. RESULTS: A significant decrease in the susceptibility to gentamicin and imipenem was observed, and more recently the highest percentages of susceptible strains were found for amikacin, cephalosporins and piperacillin/tazobactam (>80%). The probability of success of an empiric treatment or CFR for most of the evaluated antimicrobials was lower than 70% during the last two-year period. Only meropenem provided high probabilities (>90%) to achieve the PK/PD target. Cephalosporins provided moderate probabilities (>80%) although for ceftazidime, the highest dose (2g/8h) was required. Moreover, a significant decrease in the CFR trend for ciprofloxacin, imipenem and levofloxacin was observed. CONCLUSIONS: Both susceptibility rates and CFR values have to be considered together to optimize the antimicrobial dose regimen for clinical making-decisions. They are complementary tools and, they should be used jointly in surveillance programmes. In fact, susceptibility data are not always useful to detect changes in the CFR. No relevant differences were observed among the methods for handling repeated isolates.