Multiresistant Microorganisms Research Articles

Gram-Negative Bacteria and Antibiotic Resistances Isolated from Endotracheal Aspirate Samples of Patients Hospitalized in the Intensive Care Unit: 3-Years Retrospective Analysis

Intensive care units (ICUs) are the most frequent department where hospital-acquired infections caused by multi-resistant microorganisms. Ventilator-associated pneumonia (VAP) is one of the most common serious infections in intensive care units with high mortality rate. In this study, it was aimed to determine the microorganisms and their antibiotic resistance rates of endotracheal aspirate (ETA) samples taken from patients who applied mechanical ventilation in our hospital's ICU. Gram negative microorganisms isolated from ETA samples sent from patients hospitalized at ICU between January 2016 and December 2018 were included in this study. For identification of the growing strains, matrix-mediated laser desorption ionization-flight time mass spectrometry (MALDI-TOF) (VITEK-MS, bioMérieux, France), VITEK 2 automated system (bioMérieux, France) were used to determine antibiotic susceptibility. The antibiotic susceptibility of the strains was evaluated according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. A total of 385 Gram negative microorganisms were isolated from ETA specimens with significant growth over the three-year period. When analyzing the distribution of microorganisms, A. baumannii (34.2%) was in the first place, followed by P. aeruginosa and K. pneumoniae. There was no significant difference in bacterial distribution in the three-year period. A. baumannii strains showed high levels of carbapenem resistance (94%), while the most effective antibiotics were colistin and tigecycline. Carbapenem and colistin resistance in P. aeruginosa strains were determined as 27% and 6.5%, respectively. Tigecycline was found to be the most effective antibiotic with 8% resistance rate in K. pneumoniae isolates. The high carbapenem resistance seen in A. baumannii strains isolated in our study is remarkable. Increased colistin resistance in K. pneumoniae shows that the last line drugs are also in danger. It is thought that following the antimicrobial resistance patterns of the ICU regularly, updating the treatment protocols in this direction and applying the infection control measures carefully will contribute to both the success of the treatment and the reduction of the resistance rates. Keywords: Endotracheal aspirate, intensive care units, antibiotic resistance. Special Issue of Health Sciences DOI: 10.7176/JSTR/6-03-31

Polyplexes System to Enhance the LL-37 Antimicrobial Peptide Expression in Human Skin Cells.

Inefficient autologous tissue recovery in diverse skin injuries increases the susceptibility of patients to infections caused by multiresistant microorganisms, resulting in a high mortality rate. Nonviral transfection is an attractive alternative for these patients, where genetically modified cells incorporated into skin substitutes could release additional antimicrobial agents into the native skin. In this work, we have modulated the conditions of using a nonviral system for transfection of primary human keratinocytes and fibroblasts, consisting of a polymer/plasmid DNA (pDNA) complex called polyplex and its effects on the expression of LL-37 antimicrobial peptide. Linear and branched polyethylenimine (PEI) polymers in different weight concentrations were varied for evaluating the formation and colloidal characteristics of the polyplexes. The PEI/pDNA polyplexes with 19 nitrogen/phosphate ratio are nanometric particles (400 and 250 nm with linear and branched PEI, respectively) exhibiting positive surface (+30 ± 2 mV). Both kinds of polyplexes allowed the expression of a reporter gene and increased the human cathelicidin antimicrobial peptide gene expression in transfected keratinocytes and fibroblasts; however, greater cytotoxicity was observed when polyplexes formed with branched PEI were used. Moreover, cell culture supernatants from transfected cells with linear PEI/pDNA polyplexes showed enhanced antimicrobial activity (decrease of bacterial growth in 95.8%) against a Staphylococcus aureus strain in vitro. The study of the PEI/pDNA polyplexes formation allowed us to develop an improved transfection strategy of skin cells, promoting the production of LL-37 antimicrobial peptide. In the future, this strategy could be used for the construction of skin substitutes to prevent, reduce, or eliminate bacterial infections. Impact statement The results of this study contribute to the understanding of the polyplexes system in the genetic modification of skin cells and its effects on the expression of the LL-37 antimicrobial peptide. In the future, three-dimensional skin substitutes built with these cells could be an efficient way to decrease bacterial growth and prevent the infections in skin wounds.

QuEChER method for air microbiological monitoring in hospital environments

Nosocomial pathogens have become a priority issue for public health, since they are responsible for increased morbidity and mortality in hospitalized patients and the development of multi-resistant microorganisms, as well. Recent studies found strong evidence that airborne transmission plays a key role in many nosocomial infections. Thus, we aim to develop a QuEChER methodology for the characterization of airborne microbial levels, analyzing potential variables that modify the air microbiological load. Particulate matter levels and suspended and settled bioaerosols were determined simultaneously employing optical sensors, Harvard impactors and settle plates, respectively. Environmental variables were also measured at different sites during different working shifts and seasons. We found a straightforward relationship between airborne particles, air exchange rates, and people influx. Levels of suspended microorganisms were related to fine particulate matter concentration, CO2 and ambient temperature. A positive linear relationship (R2 = 0.9356) was also found between fine particulate matter and CO2 levels and air microbial load. The QuEChER methodology is an effective methodology that could be used to improve the surveillance of nosocomial pathogens in developing countries hospitals where air quality is scarcely controlled.

Antibiotic Potential and Chemical Composition of the Essential Oil of Piper caldense C. DC. (Piperaceae)

Infections by multiresistant microorganisms have led to a continuous investigation of substances acting as modifiers of this resistance. By following this approach, the chemical composition of the essential oil from Piper caldense leaf and its antimicrobial potential were investigated. The antimicrobial activity was determined by broth microdilution method providing values for minimum inhibitory concentration (MIC), IC50, and minimum fungicidal concentration (MFC). The essential oil was tested as a modulator for several antibiotics, and its effect on the morphology of Candida albicans (CA) strains was also investigated. The chemical characterization revealed an oil composed mainly of sesquiterpenes. Among them are caryophyllene oxide (13.9%), spathulenol (9.1%), δ-cadinene (7.6%) and bicyclogermacrene (6.7%) with the highest concentrations. The essential oil showed very low activity against the strains of CA with the lowest values for IC50 and MFC of 1790 μg/mL and 8192 μg/mL, respectively. The essential oil modulated the activity of fluconazole against CA URM 4387 strain, which was demonstrated by the lower IC50 obtained, 2.7 μg/mL, whereas fluconazole itself presented an IC50 of 7.76 μg/mL. No modulating effect was observed in the MFC bioassays. The effect on fungal morphology was observed for both CA INCQS 40006 and URM 4387 strains. The hyphae projection was completely inhibited at 4096 μg/mL and 2048 μg/mL, respectively. Thus, the oil has potential as an adjuvant in antimicrobial formulations.

Nuevos antibióticos en la era de la multiresistencia: revisión sobre ceftolozano/tazobactam y ceftazidima/avibactam

In recent years, new antimicrobials have been developed to combat infections caused by multidrug-resistant microorganism (MDR), including combinations between β-lactam agents (BL) and β-lactamase inhibitors (IBL). Two new combinations of BL / IBL are available in our country: ceftolozano / tazobactam (C / T) and ceftazidime / avibactam (CAZ / AVI). The addition of tazobactam to ceftolozano increases in vitro activity against microorganisms producing extended spectrum BL (ESBL), so the combination has a potent intrinsic activity against P. aeruginosa. For its part, CAZ / AVI retains the characteristics that define the activity profile of ceftazidime, to which with the addition of avibactam it presents a potent inhibitory activity against ESBL and carbapenemases (KPC, β-lactamases of class C and some of class D). A review of the published evidence is presented below. Based on this, and considering the current situation of increasing rates of antimicrobial resistance, particularly in Gram-negative bacilli, we consider that the use of C/T or CAZ/AVI is an excellent alternative for the management of serious infections caused by multi-resistant microorganisms. However, its use empirically is not recommended, except in specific and strictly selected situations, and in the context of a program for the rational use of antibiotics, under the control of the responsible infectious disease team.

Prevalence of Klebsiella pneumoniae carbapenemase - and New Delhi metallo-beta-lactamase-positive K. pneumoniae in Sergipe, Brazil, and combination therapy as a potential treatment option.

INTRODUCTION:Carbapenem-resistant Klebsiella pneumoniae infection lacks treatment options and is associated with prolonged hospital stays and high mortality rates. The production of carbapenemases is one of the most important factors responsible for this multi-resistance phenomenon.METHODS:In the present study, we analyzed the presence of genes encoding carbapenemases in K. pneumoniae isolates circulating in one of the public hospitals in the city of Aracaju, Sergipe, Brazil. We also determined the best combination of drugs that display in vitro antimicrobial synergy. First, 147 carbapenem-resistant K. pneumoniae isolates were validated for the presence of blaKPC, bla GES, bla NDM, bla SPM, bla IMP, bla VIM, and bla OXA-48 genes using multiplex polymerase chain reaction. Thereafter, using two isolates (97 and 102), the role of double and triple combinational drug therapy as a treatment option was analyzed.RESULTS:Seventy-four (50.3%) isolates were positive for bla NDM, eight (5.4%) for bla KPC, and one (1.2%) for both bla NDM and bla KPC. In the synergy tests, double combinations were better than triple combinations. Polymyxin B and amikacin for isolate 97 and polymyxin B coupled with meropenem for isolate 102 showed the best response.CONCLUSIONS:Clinicians in normal practice use multiple drugs to treat infections caused by multi-resistant microorganism; however, in most cases, the benefit of the combinations is unknown. In vitro synergistic tests, such as those described herein, are important as they might help select an appropriate multi-drug antibiotic therapy and a correct dosage, ultimately reducing toxicities and the development of antibiotic resistance.

Efecto antibacteriano del extracto metanólico de Salix babylonica sobre bacterias de importancia en salud pública

The excessive use of antibiotics, has generated resistance of microorganisms to these, have been searched effectives alternatives for treating diseases caused by resistant or multiresistant microorganism, within of these alternatives are plants, which by its content of secondary compounds have antibacterial activity. The aim on the present experiment was characterize and determine the antibacterial activity of methanolic extract of Salix babylonica (SB) against important bacteria in public health. To obtain extract, the maceration technique was used, qualitative and quantitative (gas chromatography) chemical characterization was carried. For antibacterial activity, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) was determined, the characterization of the extract allowed the identification of phenolic compounds, coumarins, lactones, flavonols, quinones, saponins, triterpenes and steroidal compounds, also Thymol (0.5319 mg/mL) and Carvacrol (0.4158 mg/mL). The extract showed the best activity against Bacillus. subtilis (MIC: 12.5 mg/mL and WBC: 25 mg/mL), Listeria. monocytogenes and Staphylococcus. aureus (MIC: 25 mg/mL and MBC: 50 mg/mL). It is concluded that the methanolic extract of SB can be an alternative for the treatment of diseases produced by resistant or multiresistant bacteria to antibiotics.

Adecuación del uso de antibióticos de “Categoría Especial” en el Servicio de Urgencias de un hospital de tercer nivel

RESUMENObjetivoAnalizar la adecuación de las prescripciones de antibióticos de categoría especial (ATB de CE) en el Servicio de Urgencias Hospitalario (SUH) de un centro urbano de tercer nivel.Material y métodosSe seleccionó una muestra aleatoria de 100 pacientes diferentes a los que se les inició un ATB de CE en Urgencias durante el año 2018. El equipo investigador revisó la historia clínica del episodio de urgencias y de ingreso. Se determinó mediante regresión logística los factores independientes asociados con el grado de adecuación del tratamiento.ResultadosSe analizaron 97 prescripciones de las cuales 66 (68%) cumplían los criterios de prescripción adecuada. El grado de adecuación fue del 70% si la infección estaba relacionada con la asistencia sanitaria y del 75% si el paciente tenía factores de riesgo de infección por microorganismos multirresistentes (MMR). El porcentaje de adecuación fue mayor en los casos en los que se especificó el foco de la infección (72%) y la gravedad del episodio (73%). Las variables independientes que se asociaron a una prescripción adecuada fueron: la presencia de factores de riesgo de infección por MMR (OR: 2,35 IC 95%: 1,65 – 3,17 p: 0,01), el especificar el foco de la infección (OR: 3,79 IC 95%: 1,72 – 4,22 p: 0,02) y señalar la gravedad del episodio (OR: 3,09 IC 95%: 1,12 – 3,09 p: 0,03).ConclusionesLa prescripción de los ATB de CE en el SUH es adecuada en la medida que se tenga en cuenta el ámbito de adquisición de la infección, los factores de riesgo de MMR, el foco de infección y la gravedad del cuadro clínico.

Cost-effectiveness of antimicrobial treatment for inpatients with carbapenem-resistant Klebsiella pneumoniae infection: a systematic review of economic evidence.

The objective of this review was to evaluate the cost-effectiveness of antimicrobial therapy for patients with carbapenem-resistant Klebsiella pneumoniae infection. Among the main multi-resistant microorganisms, carbapenem-resistant K. pneumoniae is responsible for the mortality of 40% of patients following 30 days of infection. Treatment for carbapenem-resistant K. pneumoniae infection entails the use of high-cost antimicrobials. Inappropriate use of antimicrobials can increase the cost of treatment fourfold. This review aimed to evaluate the cost-effectiveness of antimicrobial therapy treatment for patients with carbapenem-resistant K. pneumoniae infection to better inform decision making in hospital services. The review included studies on participants 18 years or over with carbapenem-resistant K. pneumoniae infection who had undergone antimicrobial therapy in hospital and acute care services. Studies that compared the cost-effectiveness of different antimicrobial therapy for carbapenem-resistant K. pneumoniae infection were included. Outcome measures were cost per unit of effect expressed in clinical outcome units; this included cost per avoided death, cost per prevention of sepsis and cost per duration of stay. Economic studies with a cost-effectiveness design were considered, as well as modeling studies. A three-step search strategy was utilized to locate studies published in English, Spanish or Portuguese, with no date restrictions. Two independent reviewers screened titles and abstracts and the full texts of potentially relevant studies for eligibility. Methodological quality was assessed by two independent reviewers using the JBI critical appraisal checklist for economic evaluations. Data were extracted from included studies using the standardized JBI data extraction tool. Data were synthesized using narrative, tables and the JBI Dominance Ranking Matrix. This review identified eight studies that evaluated the cost-effectiveness of different treatments for carbapenem-resistant K. pneumoniae infection. The results of this study demonstrated that there was no gold standard treatment for carbapenem-resistant K. pneumoniae infection, hence treatment was generally directed by colonization pressure and resistance profiles. Furthermore, due to the moderate quality and limited number of studies, there was high uncertainty of the values of the cost-effectiveness ratio. Ofloxacin appears to be the most cost-effective treatment; however, conclusions are limited due to the small number and low quality of studies.

Analysis of the predictive value of preventive isolation criteria in the intensive care unit

To assess the diagnostic accuracy of the criteria used to detect patients carrying multiresistant microorganisms (MRMs). A prospective observational study was carried out from May 2014 to May 2015. Polyvalent Intensive Care Unit. 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"). 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. 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). The only criterion independently associated with the ability to detect patients with MRMs upon admission to the ICU was the existence of "previous MRM".

Antibacterial PLA Fibers Containing Thiazolium Groups as Wound Dressing Materials.

The development of inherent antimicrobial polymeric fibers can contribute to overcoming the increasing problem of infectious diseases and multiresistant microorganisms. Here, we propose the preparation of poly(lactic acid) (PLA) based electrospun fibers blended with poly[2-(4-methylthiazol-5-yl)ethyl methacrylate] (PMTA), which quaternized have proven broad spectrum antimicrobial activity either in solution or solid state. We have demonstrated that quaternized PLA/PMTA fiber mats have a remarkable antibacterial activity against S. aureus. As determined by scanning electron microscopy and Raman spectroscopy, quaternized PMTA segregates toward the outmost surface of PLA/PMTA fiber leaving the thiazolium group widely available onto the fiber surfaces, facilitating the bacteria killing by contact mode.

Chemical Composition and Antimicrobial Effectiveness of Ocimum gratissimum L. Essential Oil Against Multidrug-Resistant Isolates of Staphylococcus aureus and Escherichia coli.

The study investigated the antimicrobial activity of the essential oil extract of Ocimum gratissimum L. (EOOG) against multiresistant microorganisms in planktonic and biofilm form. Hydrodistillation was used to obtain the EOOG, and the analysis of chemical composition was done by gas chromatography coupled with mass spectrometry (GC/MS) and flame ionization detection (GC/FID). EOOG biological activity was verified against isolates of Staphylococcus aureus and Escherichia coli, using four strains for each species. The antibacterial action of EOOG was determined by disk diffusion, microdilution (MIC/MBC), growth curve under sub-MIC exposure, and the combinatorial activity with ciprofloxacin (CIP) and oxacillin (OXA) were determined by checkerboard assay. The EOOG antibiofilm action was performed against the established biofilm and analyzed by crystal violet, colony-forming unit count, and SEM analyses. EOOG yielded 1.66% w/w, with eugenol as the major component (74.83%). The MIC was 1000 µg/mL for the most tested strains. The growth curve showed a lag phase delay for both species, mainly S. aureus, and reduced the growth level of E. coli by half. The combination of EOOG with OXA and CIP led to an additive action for S. aureus. A significant reduction in biofilm biomass and cell viability was verified for S. aureus and E. coli. In conclusion, EOOG has relevant potential as a natural alternative to treat infections caused by multiresistant strains.

High Phenotypic and Genotypic Diversity of Enterococcus faecium from Clinical and Commensal Isolates in Third Level Hospital.

Background: The use of antimicrobials and myeloablative chemotherapy regimens has promoted multiresistant microorganisms to emerge as nosocomial pathogens, such as vancomycin-resistant Enterococcus faecium (VREfm). We described a polyclonal outbreak of bloodstream infection caused by Efm in a hemato-oncological ward in Mexico. Our aim was to describe the clonal complex (CC) of the Efm strains isolated in the outbreak in comparison with commensal and environmental isolates. Methodology: Sixty Efm clinical, environmental, and commensal strains were included. We constructed a cladogram and a phylogenetic tree using Vitek and Multilocus sequence typing data, respectively. Results: We reported 20 new sequence types (ST), among which 17/43 clinical isolates belonged to CC17. The predominant ST in the clinical strains were ST757, ST1304, ST412, and ST770. Neither environmental nor commensal isolates belonged to CC17. The phylogeny of our collection shows that the majority of the clinical isolates were different from the environmental and commensal isolates, and only a small group of clinical isolates was closely related with environmental and commensal isolates. The cladogram revealed a similar segregation to that of the phylogeny. Conclusions: We found a high diversity among clinical, environmental, and commensal strains in a group of samples in a single hospital. Highest diversity was found between commensal and environmental isolates.

Atividade antibacteriana do óleo essencial de Melaleuca alternifolia frente a isolados multirresistentes produtores de ESBL e KPC causadores de infecções hospitalares

A produção de β-lactamases por bactérias Gram-negativas é a principal forma de resistência aos antimicrobianos, com destaque para as β-lactamases de amplo espectro (ESBL) e de carbapenemases (KPC). Como forma de controle dos microrganismos multirresistentes, os metabólitos secundários vegetais são objeto de estudo para o desenvolvimento de novos medicamentos. O óleo essencial de Melaleuca alternifolia (OTT) possui efeito antifúngico, anti-inflamatório e antimicrobiano, este último atribuído principalmente aos terpenos presentes na sua composição. Este trabalho objetivou determinar o potencial antimicrobiano de emulsões de OTT frente a isolados de Escherichia coli e Klebsiella pneumoniae multirresistentes produtores de ESBL e carbapenemases responsáveis por infecções hospitalares. A atividade antibacteriana das emulsões do óleo essencial foi determinada através da concentração inibitória mínima (CIM), pelos métodos de macrodiluição em tubos, Spot-on-the-lawn, difusão por poços em ágar e disco-difusão. As concentrações que inibiram o crescimento bacteriano variaram entre 0,25% a 1,5% para as diferentes metodologias aplicadas. As emulsões do óleo essencial de Melaleuca alternifolia inibiram o crescimento das bactérias multirresistentes, conforme observado no método da macrodiluição em tubo e Spot-on-the-lawn. A cepa hospitalar de Escherichia coli produtora de ESBL mostrou-se a cepa mais sensível, o que permite descrever o potencial antibacteriano do óleo, que deverá ser avaliado em estudos futuros como agente de controle.

Health inequities in the diagnosis and outcome of sepsis in Argentina: a prospective cohort study

BackgroundSocioeconomic variables impact health outcomes but have rarely been evaluated in critical illness. Low- and middle-income countries bear the highest burden of sepsis and also have significant health inequities. In Argentina, public hospitals serve the poorest segment of the population, while private institutions serve patients with health coverage. Our objective was to analyze differences in mortality between public and private hospitals, using Sepsis-3 definitions.MethodsThis is a multicenter, prospective cohort study including patients with sepsis admitted to 49 Argentine ICUs lasting 3 months, beginning on July 1, 2016. Epidemiological, clinical, and socioeconomic status variables and hospital characteristics were compared between patients admitted to both types of institutions.ResultsOf the 809 patients included, 367 (45%) and 442 (55%) were admitted to public and private hospitals, respectively. Those in public institutions were younger (56 ± 18 vs. 64 ± 18; p < 0.01), with more comorbidities (Charlson score 2 [0–4] vs. 1 [0–3]; p < 0.01), fewer education years (7 [7–12] vs. 12 [10–16]; p < 0.01), more frequently unemployed/informally employed (30% vs. 7%; p < 0.01), had similar previous self-rated health status (70 [50–90] vs. 70 [50–90] points; p = 0.30), longer pre-admission symptoms (48 [24–96] vs. 24 [12–48] h; p < 0.01), had been previously evaluated more frequently in any healthcare venue (28 vs. 20%; p < 0.01), and had higher APACHE II, SOFA, lactate levels, and mechanical ventilation utilization. ICU admission as septic shock was more frequent in patients admitted to public hospitals (47 vs. 35%; p < 0.01), as were infections caused by multiresistant microorganisms. Sepsis management in the ICU showed no differences. Twenty-eight-day mortality was higher in public hospitals (42% vs. 24%; p < 0.01) as was hospital mortality (47% vs. 30%; p < 0.01). Admission to a public hospital was an independent predictor of mortality together with comorbidities, lactate, SOFA, and mechanical ventilation; in an alternative prediction model, it acted as a correlate of pre-hospital symptom duration and infections caused by multiresistant microorganisms.ConclusionsPatients in public hospitals belonged to a socially disadvantaged group and were sicker at admission, had septic shock more frequently, and had higher mortality. Unawareness of disease severity and delays in the health system might be associated with late admission. This marked difference in outcome between patients served by public and private institutions constitutes a state of health inequity.

Biosynthetic Potential of Actinomycetes from Helianthemum stevenii Rupr. Ex Juz. &amp; Pozd. Rhizosphere

Background. Today the actual problems of humanity are the high frequency of the emergence of new multi-resistant pathogenic microorganisms, lack of food and pollution, especially agro-ecosystems. Screening of new natural products and introducing them in medicine, veterinary medicine, agriculture, etc. is one of the approaches to solving these problems. Objects of particular interest are actinomycetes – record holders in the production of biologically active compounds. Objective. The purpose of the paper is evaluation of the biosynthetic properties of actinomycetes from the rhizosphere of the endemic Helianthemum stevenii Rupr. Ex Juz & Pozd. from Crimean peninsula. Methods. Samples of the H. stevenii Rupr. Ex Juz & Pozd. rhizosphere were taken on the southern slopes of the Nikita Range (Crimean Peninsula). Actinomycetes were isolated by direct sowing of the washed rhizosphere, aqua solution of phenol treatment of the roots, or by heating them at 100 °C within 60 minutes and sowing on the nutrient medium. Antibacterial and anti-candidiasis activities were studied by culturing the actinomycetes strains by a prick on the oat medium and pouring the 0.7% agar with a certain test culture. Antifungal properties were studied by putting the agar block with a 5-day fungal culture on cups with 3-day cultures of actinomycetes and subsequent incubation for 4 days. An activity index (AI) was determined by the ratio of the diameter zone of the inhibit growth test-cultures to the diameter of the actinomycetes colonies. Phytostimulants and enzymatic properties were studied by commonly accepted methods. Results. 107 actinomycetes strains from H. stevenii Rupr. Ex Juz. & Pozd. rhizosphere were isolated. 23.2% of isolates inhibited growth of one or more typical microbial test cultures which are capable of causing a disease in humans. 8.4% of the actinomycetes strains were antagonists of S. аureus , the less actinomycetes strains inhibited gram-negative test cultures. AI of these strains was no more than 3. 80.1% of isolates were antagonists of at least one strain of the phytopathogenic bacteria. AI of these strains was from 1.2 to 13. Antifungal activity was in the 15.9% of isolates and their AI was no more than 3. 17.8 of actinomycetes strains were capable of producing indole-3-acetic acid, 10.3% – siderophores and 14.2% – phosphate solubilizers. A significant proportion of actinomycetes strains was capable of producing hydrolytic enzymes: amylases, lipases, pectinases and proteases. 29.9% of isolates can discolour Azure B and 8.4% are potentially laccase producers. Conclusions. The ability of actinomycetes strains from H. stevenii Rupr. Ex Juz. & Pozd. rhizosphere to produce antimicrobial compounds, enzymes and plants growth promoting (PGP) compounds was evaluated. Actinomycetes strains with wide range and specific inhibit certain pathogenic strain were selected as well as strains that specifically inhibit the growth of a particular strain of pathogenic microorganisms. A number of phytopathogenic bacteria antagonists tend to phytostimulation. The producers of hydrolases and oxidoreductase were isolated.

NASAL COLONIZATION BY GRAM-NEGATIVE BACTERIA IN DENTAL SURGEONS: INTERFACES BETWEEN PREVENTION AND CONTROL MEASURES

The work conditions of dental surgeons (DS), associated with low compliance to precautionary standards, often lead to the colonization and dissemination of infectious agents. To assess the epidemiological and microbiological aspects of nasal colonization by Gram-negative bacteria in DS while teaching (dentistry teachers). The data were collected by application of a questionnaire and a nasal swab. The biochemical identification, the susceptibility profile and the detection of β-lactamases were carried out in Vitek 2 compact®. 41 (77.3%) DS participated in the study, nine of them (22.0%) presented nasal colonization by Enterobacteriaceae, the participants were predominantly men (27/65.9%), over 50 years of age (24/58.5%). All ofthem confirmed using procedure gloves and a surgical mask while attending patients, with frequent (95.5%) hand washing although a statistical difference was found regarding personal habits (p=0.03). Enterobacter aerogenes (60.0%) was the most prevalent species, followed by Citrobacter koseri (20.0%). The intrinsic production of AmpC β-lactamase by E. aerogenes species, which is multiresistant to antimicrobials, was present in the nasal cavity of 14.6% of the DS. There were high levels of nasal colonization by Enterobacteriaceae in teaching DS (22.0%), 14.6% had been colonized by multiresistant microorganisms and the results wereassociated with inadequate personal habits.

Perfil de sensibilidade a antimicrobianos de bactérias patogênicas humanas isoladas de leite cru

A presença de bactérias no leite cru, associada ao possível uso indiscriminado de antimicrobianos no gado leiteiro, pode influenciar no surgimento de bactérias resistentes. O perfil de sensibilidade a antimicrobianos de seis cepas bacterianas patogênicas, isoladas de leite cru do estado do Maranhão (Acinetobacter septicus, Hafnia alvei, Lactococcus garvieae, Staphylococcus epidermidis, Pantoea spp. e Klebsiella spp.), foi avaliado neste estudo por meio do teste de antibiograma por difusão de disco em Ágar Müeller Hinton, e para a interpretação das categorias de sensibilidade foram utilizados os critérios previamente estabelecidos. O antimicrobiano com menor eficiência foi a lincomicina, onde 83,33 % das cepas apresentaram resistência. A gentamicina e a tetraciclina apresentaram 100% de eficiência frente os isolados deste estudo. Klebsiella spp. destacara-se por apresentar resistência &gt;50% aos antimicrobianos testados. No entanto, observou-se multirresistência em 50% dos isolados: Hafnia alvei, Pantoea spp. e Klebsiella spp. Os resultados verificados demonstram a multirresistência de patógenos de grande importância para a saúde pública, e o leite cru como uma possível fonte de veiculação desses micro-organismos multirresistentes.

A comprehensive characterization of polyphenols by LC-ESI–QTOF-MS from Melipona quadrifasciata anthidioides geopropolis and their antibacterial, antioxidant and antiproliferative effects

The geopropolis is a unique type of propolis produced by some stingless bee species. This product is known in folk medicine for its pharmacological properties, mainly antimicrobial and antioxidant, but there are few scientific studies that prove these properties. The objective of this study was to evaluate the phenolic composition and the antimicrobial, antioxidant and antiproliferative activities of Melipona quadrifasciata geopropolis. The phenolic characterization of the geopropolis ethanolic extract was evaluated by LC-ESI-QTOF-MS. The antimicrobial activity was carried out against Gram-positive (including multiresistant microorganisms), negative and yeast. The synergistic effect was evaluated in association with Sulfamethoxazole + Trimethoprim. DPPH, ABTS, FRAP, ORAC and HPLC on-line were used to evaluate the antioxidant activity. Antiproliferative activity was assessed by the sulforhodamine B assay. Flavonoids and phenolic acids were identified in the extract, which showed promising antimicrobial activity, partially synergistic effect and antioxidant activity.

Infections related to healthcare in patients hospitalized in a Urology service: Resistance patterns and adequacy of empirical antibiotic treatment as a prognostic factor

ObjectivesTo evaluate the suitability of empirical antibiotic therapy in HAIs and the antibiotic resistance patterns of the responsible microorganisms, as well as the incidence of mortality and risk factors involved. MethodA prospective observational study was carried out on patients of both sexes older than 16years, admitted by any urological process during a period of 4years. The incidence and characteristics of HAIs, as well as the causative organism and its resistance, the initial empirical antibiotic therapy and its modification, if required, and mortality rates are analyzed. ResultsOut of 6546 patients, 6.3% suffered HAIs, 70.5% corresponding to urinary tract infection and 22.1% to infection of the surgical wound. E.coli, Enterococcus spp., Klebsiella spp. y P.aeruginosa were the most frequently implicated (25.1%, 17.5%, 13.5% and 12.3%, respectively). E.coli and Klebsiella spp. were producers of extended-spectrum beta-lactamases (ESBL) in 24.7% and 47.8%, respectively. 4.3% of Klebsiella and 33.3% of Pseudomonas were carbapenems-resistant. The overall resistance to quinolones was approximately 50%. The most commonly used antibiotics for empirical therapy were cephalosporins of 3rd and 4th generation (33.6%) and carbapenems (28.2%). An overall rate of adequacy of empirical antibiotic therapy of 82.9% was obtained. The mortality rate in patients with HAIs was 2.2%, compared with 0.3% in patients without infection. In a multivariate analysis, the variables associated with the highest mortality risk were the isolation of ESBL-producing enterobacteria and the inadequate empirical antibiotic treatment. ConclusionsThe selection of empirical antibiotic therapy was quite accurate. An increase in HAIs by multiresistant microorganisms, such as ESBL Enterobacteria or multiresistant P.aeruginosa is being observed. The mortality risk increases with inadequate initial empirical antibiotic therapy or when the responsible microorganism is an ESBL enterobacteria.