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Water-filled sinkholes known locally as cenotes, found on the Yucatán Peninsula, have remarkable biodiversity. The primary objective of this study was to explore the biotechnological potential of Gram-positive cultivable bacteria obtained from sediment samples collected at the coastal cenote Pol-Ac in Yucatán, Mexico. Specifically, the investigation aimed to assess production of hydrolytic enzymes and antimicrobial compounds. 16 S rRNA gene sequencing led to the identification of 49 Gram-positive bacterial isolates belonging to the phyla Bacillota (n = 29) and Actinomycetota (n = 20) divided into the common genera Bacillus and Streptomyces, as well as the genera Virgibacillus, Halobacillus, Metabacillus, Solibacillus, Neobacillus, Rossellomorea, Nocardiopsis and Corynebacterium. With growth at 55ºC, 21 of the 49 strains were classified as moderately thermotolerant. All strains were classified as halotolerant and 24 were dependent on marine water for growth. Screening for six extracellular hydrolytic enzymes revealed gelatinase, amylase, lipase, cellulase, protease and chitinase activities in 93.9%, 67.3%, 63.3%, 59.2%, 59.2% and 38.8%, of isolated strains, respectively. The genes for polyketide synthases type I, were detected in 24 of the strains. Of 18 strains that achieved > 25% inhibition of growth in the bacterial pathogen Staphylococcus aureus ATCC 6538, 4 also inhibited growth in Escherichia coli ATCC 35,218. Isolates Streptomyces sp. NCA_378 and Bacillus sp. NCA_374 demonstrated 50-75% growth inhibition against at least one of the two pathogens tested, along with significant enzymatic activity across all six extracellular enzymes. This is the first comprehensive report on the biotechnological potential of Gram-positive bacteria isolated from sediments in the cenotes of the Yucatán Peninsula.

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Staphylococcus aureus infections are a severe health problem due to the high mortality rate. Conventional treatment of these infections is via the administration of antibiotics. However, its indiscriminate use can select resistant microorganisms. Thus, it is necessary to develop alternatives for antibiotic therapy. Antimicrobial Photodynamic Therapy (aPDT), a therapeutic method that associates a photosensitizer (PS), a light source with adequate wavelength to the PS, interacts with molecular oxygen generating reactive oxygen species responsible for cell inactivation, is a viable alternative. This work aimed to analyze, in vitro and in vivo, the action of aPDT with PS Photodithazine® (PDZ) on the methicillin-resistant S. aureus (MRSA) strain. In the in vitro method, the S. aureus biofilm was incubated with PDZ at 50 and 75 µg.mL-1 for 15 min, adopting the light dose of 25, 50, and 100 J/cm2. In addition, PS interaction, formation of reactive oxygen species (ROS), bacterial metabolism, adhesion, bacterial viability, and biofilm structure were evaluated by scanning electron microscopy. Subsequently, the strain was inoculated into models of Galleria mellonella, and the survival curve, health scale, blood cell analysis, and CFU/mL of S. aureus in the hemolymph were analyzed after aPDT. In the in vitro results, bacterial reduction was observed in the different PDZ concentrations, highlighting the parameters of 75 µg.mL-1 of PDZ and 100 J/cm2. As for in vivo results, aPDT increased survival and stimulated the immune system of G. mellonella infected by S. aureus. aPDT proved effective in both models, demonstrating its potential as an alternative therapy in treating MRSA bacterial infections.

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Otitis media with effusion (OME) is a type of otitis media (OM) characterized by the presence of fluid behind intact tympanic membrane and is one of the most common diseases of early childhood. It is an infectious disease associated with the presence of many pathogenic bacteria in the middle ear of affected individuals. This study was aimed to determine the prevalence of Gram-positive bacteria from the middle ear of OME patients in the population of Southern Punjab, Pakistan. The incidence of OME under comprehensive healthcare setting was investigated in patients who consulted at the department of ear, throat and nose, Bahawal Victoria Hospital (BVH), Bahawalpur, from December, 2019 to May, 2021. Ear swabs were taken from affected and normal individuals. After culturing bacteria from the ear swabs, microscopic analysis and biochemical tests were performed to characterize the cultured Gram-positive bacteria. Out of 352 patients examined, 109 (30.9%) patients had OME. Age of the participants ranged from 14 to 50 years; individuals between the ages of 14 and 22 years had the highest infection rates, while individuals between 40 and 50 years had the lowest rate of infection. Tympanic membrane perforation, fever, cough, sore throat, ear pain and hearing problem showed association with symptoms of OME. Microscopic analysis and biochemical characterization showed the presence of streptococci and staphylococci in all the studied samples. The most frequently isolated bacteria were Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus with percentage of 53.3%, 20% and 13.3% respectively. Enterococcus faecalis (6.6%) and Staphylococcus epidermidis (6.6%) were also identified in the studied samples. This study will help in the better medical administration of OME affected individuals.

A otite média com efusão (OME) é um tipo de otite média (OM) caracterizada pela presença de líquido atrás da membrana timpânica intacta e é uma das doenças mais comuns durante a primeira infância. Trata-se de uma doença infecciosa associada à presença de muitas bactérias patogênicas na orelha média dos indivíduos afetados. Este estudo teve como objetivo determinar a prevalência de bactérias Gram-positivas do ouvido médio de pacientes com OME na população do sul de Punjab, Paquistão. A incidência de OME em ambiente de saúde abrangente foi investigada em pacientes que consultaram no departamento de ouvido, garganta e nariz, Hospital Bahawal Victoria (BVH), Bahawalpur, de dezembro de 2019 a maio de 2021. Cotonetes de orelha foram coletados de indivíduos afetados e normais. Após a cultura das bactérias dos swabs auriculares, análises microscópicas e testes bioquímicos foram realizados para caracterizar as bactérias Gram-positivas cultivadas. Dos 352 pacientes examinados, 109 (30,9%) apresentavam OME. A idade dos participantes variou de 14 a 50 anos; indivíduos entre 14 e 22 anos apresentaram as maiores taxas de infecção, enquanto indivíduos entre 40 e 50 anos apresentaram as menores taxas de infecção. Perfuração da membrana timpânica, febre, tosse, dor de garganta, dor de ouvido e problema de audição apresentaram associação com sintomas de OME. A análise microscópica e a caracterização bioquímica mostraram a presença de estreptococos e estafilococos em todas as amostras estudadas. As bactérias isoladas com maior frequência foram Streptococcus pneumoniae, Streptococcus pyogenes e Staphylococcus aureus com percentuais de 53,3%, 20% e 13,3%, respectivamente. Enterococcus faecalis (6,6%) e Staphylococcus epidermidis (6,6%) também foram identificados nas amostras estudadas. Este estudo ajudará na melhor administração médica de indivíduos afetados por OME.

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Anti-microbial peptides play a vital role in the defense mechanisms of various organisms performing functions that range from the elimination of microorganisms, through diverse mechanisms, to the modulation of the immune response, providing protection to the host. Among these peptides, cathelicidins, a well-studied family of anti-microbial peptides, are found in various animal species, including reptiles. Due to the rise in anti-microbial resistance, these compounds have been suggested as potential candidates for developing new drugs. In this study, we identified and characterized a cathelicidin-like peptide called Aquiluscidin (Aq-CATH) from transcripts obtained from the skin and oral mucosa of the Querétaro's dark rattlesnake, Crotalus aquilus. The cDNA was cloned, sequenced, and yielded a 566-base-pair sequence. Using bioinformatics, we predicted that the peptide precursor contains a signal peptide, a 101-amino-acid conserved cathelin domain, an anionic region, and a 34-amino-acid mature peptide in the C-terminal region. Aq-CATH and a derived 23-amino-acid peptide (Vcn-23) were synthesized, and their anti-microbial activity was evaluated against various species of bacteria in in vitro assays. The minimal inhibitory concentrations against bacteria ranged from 2 to 8 µg/mL for both peptides. Furthermore, at concentrations of up to 50 µM, they exhibited no significant hemolytic activity (<2.3% and <1.2% for Aquiluscidin and Vcn-23, respectively) against rat erythrocytes and displayed no significant cytotoxic activity at low concentrations (>65% cell viability at 25 µM). Finally, this study represents the first identification of an antimicrobial peptide in Crotalus aquilus, which belongs to the cathelicidin family and exhibits the characteristic features of these peptides. Both Aq-CATH and its derived molecule, Vcn-23, displayed remarkable inhibitory activity against all tested bacteria, highlighting their potential as promising candidates for further antimicrobial research.

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Bacterial resistance to multiple drugs is a worldwide problem that afflicts public health. Various studies have shown that silver nanoparticles are good bactericidal agents against bacteria due to the adherence and penetration of the external bacterial membrane, preventing different vital functions and subsequently bacterial cell death. A systematic review of ScienceDirect, PubMed, and EBSCOhost was conducted to synthesize the literature evidence on the association between the bactericidal property of silver nanoparticles on both resistant Gram-positive and Gram-negative bacteria. Eligible studies were original, comparative observational studies that reported results on drug-resistant bacteria. Two independent reviewers extracted the relevant information. Out of the initial 1 420, 142 studies met the inclusion criteria and were included to form the basis of the analysis. Full-text screening led to the selection of 6 articles for review. The results of this systematic review showed that silver nanoparticles act primarily as bacteriostatic agents and subsequently as bactericides, both in Gram-positive and Gram-negative drug-resistant bacteria.

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This manuscript presents the first report on antimicrobial photo-inactivation in vitro using tetra-cationic porphyrins with peripheral platinum(II) bipyridyl complexes against Gram-positive bacteria. Two isomeric tetra-cationic porphyrins (3TPyP and 4TPyP) were tested against clinically important bacterial species. The antimicrobial activity assays were performed at specific photosensitizer (PS) concentrations under dark and white-light LED irradiation conditions for 120 min. The porphyrin 3-PtTPyP was the most efficient PS against the bacteria tested, inhibiting bacterial growth in just 15 min and 30 min at low concentrations (3.75 and 0.45 µM). The minimal inhibitory concentration of the porphyrin increased in the presence of reactive oxygen species scavengers, indicating that singlet oxygen and radical species likely participated in the photo-oxidation mechanism. In addition, the checkerboard assay that tests the association of compounds, showed a synergistic effect, suggesting a potentiation of the antibacterial effect when porphyrin was tested in combination with ciprofloxacin and vancomycin. Thus, tetra-cationic porphyrins containing platinum(II) complexes are promising agents for microbial photo-inactivation as an alternative therapy against infections.

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Se presenta el caso de un paciente joven inmunocompetente, con antecedente de tuberculosis pulmonar, que acude al hospital por un cuadro clínico subagudo de fiebre persistente, baja de peso, disnea y abolición del murmullo vesicular. La tomografía de tórax mostró un extenso empiema en hemitórax izquierdo. Se le toman muestras para detección de gérmenes comunes y se le colocan un tubo de drenaje torácico y se inicia antibioticoterapia. La prueba de MALDI-TOF MS identificó a Parvimonas micra, una bacteria anaerobia, comensal de la flora oral, asociado a periodontitis severa, escasamente reportado en empiema pleural, especialmente, en personas inmunocompetentes. En la evaluación odontológica se realizó el diagnóstico de gingivitis y pericoronaritis de la tercera molar. El paciente evolucionó favorablemente. Se sugiere que, en casos de empiemas pleurales subagudos o crónicos, se debe considerar, además de las micobacterias, como agente etiológico al Parvimonas micra, y optar por exámenes como MALDI-TOF MS o secuenciamiento del 16S rRNA, colocación de tubo de tórax, cobertura antibiótica empírica y evaluación odontológica.

We present the case of a young immunocompetent patient, with a history of pulmonary tuberculosis, who attended the hospital with a subacute clinical picture of persistent fever, weight loss, dyspnea and abolition of vesicular murmur. Chest CT scan showed an extensive empyema in the left hemithorax. Samples were taken for detection of common germs. Then, a chest drainage tube was placed and antibiotic therapy started. The MALDI-TOF MS test identified Parvimonas micra, an anaerobic bacterium, commensal to the oral flora, associated with severe periodontitis, but rarely reported in cases of pleural empyema, especially in immunocompetent patients. Gingivitis and pericoronaritis of the third molar were diagnosed during oral evaluation. The patient progressed favorably. Parvimonas micra should be considered as a possible etiological agent in cases of subacute or chronic pleural empyema, in addition to mycobacteria. Tests such as MALDI-TOF MS or 16S rRNA sequencing, chest tube placement, empirical antibiotic coverage and an adequate oral evaluation should be considered in these cases.

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Microorganisms such as Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus are frequently isolated in samples of urinary, blood, intestinal, and respiratory infections, among others. These bacteria are also associated with microbial biofilm formation. E. coli, P. aeruginosa, and S. aureus biofilm infections are particularly hard to manage and often associated with nosocomial problems. This study investigated the influence of different culture media on E. coli, P. aeruginosa, and S. aureus biofilm formation. Bacterial performance was evaluated in brain heart infusion broth, Mueller-Hinton broth, or tryptic soy broth, with or without supplementing with different glucose levels (1-5%). The study quantified biofilm biomass and the count of viable biofilm colonies. This is the first study that compares the biofilm formation of E. coli, P. aeruginosa and S. aureus in polystyrene using different culture media and with different glucose concentrations. The most robust growth of E. coli, P. aeruginosa, and S. aureus occurred in brain heart infusion broth supplemented with 5% glucose, Mueller-Hinton broth without glucose, and tryptic soy broth with 2% glucose, respectively. Our data demonstrate that behavioral and morphological characteristics of each bacterium require a specific broth to enhance the growth of these microorganisms. These findings will contribute to future tests for therapeutic alternatives with anti-biofilm potential.

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Introducción. El 65 % de las infecciones humanas son producidas por bacterias o levaduras, cuya capacidad de formar biopelículas las hace más resistentes a los antimicrobianos y antifúngicos. Objetivo. Determinar la capacidad de formación de biopelículas en aislamientos bacterianos y fúngicos por medio de los métodos cuantitativo de microtitulación con cristal violeta y cualitativo de cultivo en agar con rojo Congo. Materiales y métodos. Con el método cuantitativo, se utilizaron los medios de cultivo infusión cerebro-corazón, tripticasa de soya y Müeller-Hinton para aislamientos bacterianos; para levaduras, se usaron caldo infusión cerebro-corazón y Sabouraud dextrosa. Para el método cualitativo de cultivo en agar, se utilizaron los mismos medios de cultivo más una solución con 3 % de rojo Congo y 10 % de dextrosa. Cómo método de referencia, se utilizó la propuesta de Stepanovic et al. Resultados. Se evaluaron 103 aislamientos bacterianos y 108 de levaduras. No es recomendable sustituir el caldo infusión cerebro-corazón por los caldos tripticasa de soya y Müeller-Hinton en el método cuantitativo, para evaluar la formación de biopelículas en los aislamientos bacterianos. El medio Sabouraud dextrosa, en caldo y agar, puede sustituir al de infusión de cerebro-corazón para evaluar la formación de biopelículas en levaduras, tanto por el método cuantitativo como por el cualitativo. Conclusión. El estudio de las biopelículas en el laboratorio de microbiología, a partir del método cualitativo de cultivo en agar con rojo Congo, es un procedimiento sencillo, rápido y de bajo costo, que proporciona información útil para el diagnóstico y la terapéutica de infecciones persistentes causadas por bacterias y levaduras.

Introduction. Sixty-five percent of human infections are caused by bacteria or yeasts able to form biofilms. This feature makes them more resistant to antimicrobials and antifungals. Objective. To determine biofilm formation capacity of bacterial and fungal isolates by quantitative crystal violet microtiter and qualitative Congo red agar methods. Materials and methods. Brain-heart infusion, trypticase soy broth and Müeller-Hinton culture media were used in bacterial isolates for the quantitative method; brain-heart infusion broth and Sabouraud dextrose were used for yeasts. The same culture media plus 3% Congo red and 10% dextrose were used to apply the qualitative method in agar. The proposal by Stepanovic, et al. was used as a reference method. Results. We evaluated 103 bacterial isolates and 108 yeasts isolates. We did not recommend substitute brain-heart infusion broth for trypticase soy and Müeller-Hinton broths for biofilm formation assessment in bacterial isolates using the quantitative method. Sabouraud dextrose medium, both broth and agar, can replace brain-heart infusion to assess biofilm formation in yeasts, quantitatively and qualitatively. Conclusion. The study of biofilms in the microbiology laboratory, using Congo red agar qualitative method, is a simple, fast, and inexpensive procedure that provides precise information for the diagnosis and treatment of persistent infections caused by bacteria and yeasts.

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Enterococci are major, recalcitrant nosocomial pathogens with a wide repertoire of intrinsic and acquired resistance determinants and the potential of developing resistance to all clinically available antimicrobials. As such, multidrug-resistant enterococci are considered a serious public health threat. Due to limited treatment options and rapid emergence of resistance to all novel agents, the clinical microbiology laboratory plays a critical role in deploying accurate, reproducible, and feasible antimicrobial susceptibility testing methods to guide appropriate treatment of patients with deep-seated enterococcal infections. In this review, we provide an overview of the advantages and disadvantages of existing manual and automated methods that test susceptibility of Enterococcus faecium and Enterococcus faecalis to ß-lactams, aminoglycosides, vancomycin, lipoglycopeptides, oxazolidinones, novel tetracycline-derivatives, and daptomycin. We also identify unique problems and gaps with the performance and clinical utility of antimicrobial susceptibility testing for enterococci, provide recommendations for clinical laboratories to circumvent select problems, and address potential future innovations that can bridge major gaps in susceptibility testing.

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Homeopathy is a therapy that uses medications prepared with infinitesimal and dynamized dilutions. Current studies demonstrate in vitro activity of homeopathy on gram-positive bacteria such as Staphylococcus aureusand Streptococcus pyogenes. Among bacterial infections, urinary tract infection (UTI) is frequent, leads to later consequences and the main causal agent is Escherichia coli(E. coli). In other publications, it has been reported inactivity of homeopathy on E. colicultures. Due to the divergence in the literature, the objective of this study was to evaluate gram-negative bacteria growth under homeopathy treatment. Methods:The medicines Atropabelladona, Cantharis, Staphysagria,and Colibacillinumwere tested at 6CH, 12CH and 30CH inE. coliATCC 25922 and EPEC (Enteropathogenic Escherichia coli) ATCC 43887. Two hundred and fifty microliters of the medicines in alcohol 30% were incubated at 37ºC with 3 mL of Müller Hinton broth (MH), 10 µL of cultures at 0.5 Macfarland and subsequent dilution at 1/10. Bacterial growth was evaluated in a spectrophotometer at 600nm, in the periods of 6, 12,and 20 hours of incubation. Resultsand Discussion:The results showed no inhibition of bacterial growth under the studied conditions. These data corroborate with studies already published that indicate the absence of action of homeopathy on E. colicultures. Considering other studies, it can be suggested that homeopathic medicines have direct activity on the growth of Gram-positive and not Gram-negative bacteria. Evaluating the two bacterial groups, it is possible to assume that the difference in homeopathy activity could be linked to differences in the bacterial wall structure. This hypothesis should be evaluated by other tests with the same bacterialstrains. Conclusion:The homeopathic medicines tested have no direct activity on Gram-negative bacteria cultures.

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Introduction: The growing resistance to antibiotics worldwide represents a global threat to public health. The larval excretions and secretions derived from necrophagous flies from the Calliphoridae family could represent a promising source for counteracting their effects. Objective: To compare the antimicrobial activity of Calliphora vicina and Sarconesiopsis magellanica (Diptera: Calliphoridae) native excretions and secretions and those weighing more than 10 kDa and less. Materials and methods: We used the turbidimetry technique for the bioassay; we determined the minimum inhibitory concentration (MIC) for excretions and secretions weighing less than 10 kDa. Results: Calliphora vicina and S. magellanica native excretions and secretions and those weighing less than 10 kDa exhibited potent antibacterial activity against three Staphylococcus aureus strains and four Gram-negative bacteria; those weighing less than 10 kDa were more effective than the native ones in the two species of flies evaluated here. Furthermore, excretions and secretions weighing less than 10 kDa had the same effectiveness, except in the MIC trials where S. magellanica excretions and secretions weighing less than 10 kDa were more potent against all the bacteria evaluated, except for S. aureus ATCC 25923. Excretions and secretions weighing more than 10 kDa did not inhibit bacterial growth. Conclusions: These results potentially validate these substances as an important source for isolating and characterizing antimicrobial agents.

Introducción. La creciente resistencia bacteriana a los antibióticos representa una amenaza mundial de salud pública. Las excreciones y secreciones larvarias derivadas de moscas necrófagas de la familia Calliphoridae podrían configurar una fuente promisoria para contrarrestar sus efectos. Objetivo. Comparar la actividad antimicrobiana de las excreciones y secreciones larvarias nativas, y de las mayores y menores de 10 kDa de Calliphora vicina y Sarconesiopsis magellanica (Diptera: Calliphoridae). Materiales y métodos. El bioensayo se hizo a partir de la técnica de turbidimetría y en el caso de las excreciones y secreciones menores de 10 kDa se determinó la concentración inhibitoria mínima (CIM). Resultados. Las excreciones y secreciones nativas y las menores de 10 kDa de C. vicina y S. magellanica, evidenciaron una potente actividad antibacteriana contra tres cepas de Staphylococcus aureus y cuatro bacterias Gram negativas, siendo las menores de 10 kDa más efectivas que las nativas en las dos especies de moscas evaluadas. Además, las menores de 10 kDa presentaron la misma efectividad, aunque en las pruebas de CIM se observó que las de S. magellanica fueron más potentes en todas las bacterias evaluadas, excepto contra la cepa de S. aureus ATCC 25923. Las mayores de 10 kDa no inhibieron el crecimiento bacteriano. Conclusión. Los resultados validaron, en general, que estas sustancias son fuente importante para el aislamiento y la caracterización de agentes antimicrobianos.

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Introducción. La creciente resistencia bacteriana a los antibióticos representa una amenaza mundial de salud pública. Las excreciones y secreciones larvarias derivadas de moscas necrófagas de la familia Calliphoridae podrían configurar una fuente promisoria para contrarrestar sus efectos. Objetivo. Comparar la actividad antimicrobiana de las excreciones y secreciones larvarias nativas, y de las mayores y menores de 10 kDa de Calliphora vicina y Sarconesiopsis magellanica (Diptera: Calliphoridae). Materiales y métodos. El bioensayo se hizo a partir de la técnica de turbidimetría y en el caso de las excreciones y secreciones menores de 10 kDa se determinó la concentración inhibitoria mínima (CIM). Resultados. Las excreciones y secreciones nativas y las menores de 10 kDa de C. vicina y S. magellanica, evidenciaron una potente actividad antibacteriana contra tres cepas de Staphylococcus aureus y cuatro bacterias Gram negativas, siendo las menores de 10 kDa más efectivas que las nativas en las dos especies de moscas evaluadas. Además, las menores de 10 kDa presentaron la misma efectividad, aunque en las pruebas de CIM se observó que las de S. magellanica fueron más potentes en todas las bacterias evaluadas, excepto contra la cepa de S. aureus ATCC 25923. Las mayores de 10 kDa no inhibieron el crecimiento bacteriano. Conclusión. Los resultados validaron, en general, que estas sustancias son fuente importante para el aislamiento y la caracterización de agentes antimicrobianos.

Introduction: The growing resistance to antibiotics worldwide represents a global threat to public health. The larval excretions and secretions derived from necrophagous flies from the Calliphoridae family could represent a promising source for counteracting their effects. Objective: To compare the antimicrobial activity of Calliphora vicina and Sarconesiopsis magellanica (Diptera: Calliphoridae) native excretions and secretions and those weighing more than 10 kDa and less. Materials and methods: We used the turbidimetry technique for the bioassay; we determined the minimum inhibitory concentration (MIC) for excretions and secretions weighing less than 10 kDa. Results: Calliphora vicina and S. magellanica native excretions and secretions and those weighing less than 10 kDa exhibited potent antibacterial activity against three Staphylococcus aureus strains and four Gram-negative bacteria; those weighing less than 10 kDa were more effective than the native ones in the two species of flies evaluated here. Furthermore, excretions and secretions weighing less than 10 kDa had the same effectiveness, except in the MIC trials where S. magellanica excretions and secretions weighing less than 10 kDa were more potent against all the bacteria evaluated, except for S. aureus ATCC 25923. Excretions and secretions weighing more than 10 kDa did not inhibit bacterial growth. Conclusions: These results potentially validate these substances as an important source for isolating and characterizing antimicrobial agents.

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Introduction. Sixty-five percent of human infections are caused by bacteria or yeasts able to form biofilms. This feature makes them more resistant to antimicrobials and antifungals. Objective. To determine biofilm formation capacity of bacterial and fungal isolates by quantitative crystal violet microtiter and qualitative Congo red agar methods. Materials and methods. Brain-heart infusion, trypticase soy broth and Müeller­Hinton culture media were used in bacterial isolates for the quantitative method; brain-heart infusion broth and Sabouraud dextrose were used for yeasts. The same culture media plus 3% Congo red and 10% dextrose were used to apply the qualitative method in agar. The proposal by Stepanovic, et al. was used as a reference method. Results. We evaluated 103 bacterial isolates and 108 yeasts isolates. We did not recommend substitute brain-heart infusion broth for trypticase soy and Müeller-Hinton broths for biofilm formation assessment in bacterial isolates using the quantitative method. Sabouraud dextrose medium, both broth and agar, can replace brain-heart infusion to assess biofilm formation in yeasts, quantitatively and qualitatively. Conclusion. The study of biofilms in the microbiology laboratory, using Congo red agar qualitative method, is a simple, fast, and inexpensive procedure that provides precise information for the diagnosis and treatment of persistent infections caused by bacteria and yeasts.

Introducción. El 65 % de las infecciones humanas son producidas por bacterias o levaduras, cuya capacidad de formar biopelículas las hace más resistentes a los antimicrobianos y antifúngicos. Objetivo. Determinar la capacidad de formación de biopelículas en aislamientos bacterianos y fúngicos por medio de los métodos cuantitativo de microtitulación con cristal violeta y cualitativo de cultivo en agar con rojo Congo. Materiales y métodos. Con el método cuantitativo, se utilizaron los medios de cultivo infusión cerebro-corazón, tripticasa de soya y Müeller-Hinton para aislamientos bacterianos; para levaduras, se usaron caldo infusión cerebro-corazón y Sabouraud dextrosa. Para el método cualitativo de cultivo en agar, se utilizaron los mismos medios de cultivo más una solución con 3 % de rojo Congo y 10 % de dextrosa. Cómo método de referencia, se utilizó la propuesta de Stepanovic et al. Resultados. Se evaluaron 103 aislamientos bacterianos y 108 de levaduras. No es recomendable sustituir el caldo infusión cerebro-corazón por los caldos tripticasa de soya y Müeller-Hinton en el método cuantitativo, para evaluar la formación de biopelículas en los aislamientos bacterianos. El medio Sabouraud dextrosa, en caldo y agar, puede sustituir al de infusión de cerebro-corazón para evaluar la formación de biopelículas en levaduras, tanto por el método cuantitativo como por el cualitativo. Conclusión. El estudio de las biopelículas en el laboratorio de microbiología, a partir del método cualitativo de cultivo en agar con rojo Congo, es un procedimiento sencillo, rápido y de bajo costo, que proporciona información útil para el diagnóstico y la terapéutica de infecciones persistentes causadas por bacterias y levaduras.

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Bacillus clausii is a gram-positive rod used as a probiotic to treat diarrhea and the side effects of antibiotics such as pseudomembranous colitis. We report a case of B. clausii bacteremia in a non-immunocompromised patient with active peptic ulcer disease and acute diarrhea. The probiotic was administered during the patient´s hospitalization due to diarrhea of infectious origin. B. clausii was identified in the bloodstream of the patient through Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) days after her discharge. Given the wide use of probiotics, we alert clinicians to consider this microorganism as a causative agent when signs of systemic infection, metabolic compromise, and hemodynamic instability establish after its administration and no pathogens have been identified that could explain the clinical course.

Bacillus clausii es un bacilo grampositivo que se utiliza como probiótico para tratar la diarrea y los efectos secundarios de los antibióticos como la colitis pseudomembranosa. Presentamos un caso de bacteriemia por B. clausii en un paciente no inmunodeprimido con enfermedad ulcerosa péptica activa y diarrea aguda. El probiótico se administró durante la hospitalización del paciente por diarrea de origen infeccioso. B. clausii se identificó en el torrente sanguíneo de la paciente a través del tiempo de vuelo por ionización por desorción láser asistida por matriz (MALDI-TOF) días después de su alta. Dado el amplio uso de probióticos, alertamos a los médicos para que consideren este microorganismo como agente causal cuando se establezcan signos de infección sistémica, compromiso metabólico e inestabilidad hemodinámica después de su administración y no se hayan identificado patógenos que puedan explicar el curso clínico.

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Abstract | Bacillus clausii is a gram-positive rod used as a probiotic to treat diarrhea and the side effects of antibiotics such as pseudomembranous colitis. We report a case of B. clausii bacteremia in a non-immunocompromised patient with active peptic ulcer disease and acute diarrhea. The probiotic was administered during the patient's hospitalization due to diarrhea of infectious origin. B. clausii was identified in the bloodstream of the patient through Matrix- Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) days after her discharge. Given the wide use of probiotics, we alert clinicians to consider this microorganism as a causative agent when signs of systemic infection, metabolic compromise, and hemodynamic instability establish after its administration and no pathogens have been identified that could explain the clinical course.

Resumen | Bacillus clausii es un bacilo Gram positivo usado como probiótico para tratar la diarrea y efectos adversos de los antibióticos, como la colitis pseudomembranosa. Se reporta un caso de bacteriemia por B. clausii en una paciente inmunocompetente con enfermedad ulcerosa péptica activa y diarrea aguda. El probiótico le fue administrado durante la hospitalización debido al origen infeccioso de la diarrea. B. clausii se identificó en el torrente sanguíneo de la paciente, utilizando espectrometría de desorción/ionización mediante láser asistido por matriz (Matrix-Assisted Laser Desorption/Ionization, MALDI), acoplada a un detector de iones (Time of Flight, TOF) (MALDI-TOF), días después de haber sido dada de alta. Dado el amplio uso de los probióticos, alertamos a los clínicos para que consideren este microorganismo como agente causal cuando se detecten signos de infección sistémica, compromiso metabólico, e inestabilidad hemodinámica tras su administración, y no se haya identificado ningún patógeno que pueda explicar el cuadro clínico.

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Abstract Streptococcus constellatus is a member of the group now called Streptococcus anginosus. This microorganism is part of the normal oropharyngeal, gastrointestinal and genitourinary microbiota. However, it may cause serious infections such as pharyngitis, bacteremia and invasive pyogenic infections in immunocompromised patients. We report the first case in Colombia of an adult male with no relevant medical history and with an unusual presentation of infection by S. constellatus and whose laboratory results showed an important systemic inflammatory response and radiographic evidence of abdominal involvement with poor response to medical and surgical management. Since there are few reports in international medical journals about intra-abdominal infection by S. constellatus and taking into consideration the need of a multidisciplinary intervention, this report may be of interest for both clinical and surgical practitioners.

Resumen Streptococcus constellatus es un miembro del grupo ahora llamado Streptococcus anginosus. Este microorganismo es parte de la microbiota orofaríngea, gastrointestinal y genitourinaria normal. Sin embargo, puede causar infecciones graves como faringitis, bacteriemia e infecciones piógenas invasivas en pacientes inmunocomprometidos. Presentamos el primer caso en Colombia de un hombre adulto sin antecedentes médicos relevantes y con una presentación inusual de infección por S. constellatus, dada por una gran respuesta inflamatoria sistémica y evidencia radiográfica de afectación abdominal con mala respuesta al tratamiento médico y quirúrgico. Dado que hay pocos informes en revistas médicas internacionales sobre la infección intraabdominal por S. constellatus y teniendo en cuenta la necesidad de intervenciones multidisciplinarias, este reporte puede ser de interés tanto para los médicos clínicos como para los quirúrgicos.

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Introducción: La identificación de los principales factores clínico-epidemiológicos que determinan causas de mortalidad en pacientes hospitalizados es una necesidad apremiante, principalmente cuando los esfuerzos realizados en la actualidad no permiten asumir acciones fundamentadas en la identificación de las causas de dicho evento. Objetivo: Establecer cuáles son los factores pronósticos de mortalidad por agente infeccioso en un hospital de alta complejidad de la ciudad de Cartagena- Colombia. Material y Métodos: Se realizó un estudio de casos y controles retrospectivo, con muestra proyectada de 86 casos y 258 controles, en una relación 1:3, que cumplieron con los criterios de elegibilidad respectivos y en los que realizaron análisis bivariados y posteriormente un análisis multivariado que incluyó métodos de regresión logística binaria. Resultados: El riesgo de mortalidad en el análisis multivariado está determinado por variables como sexo masculino (ORa 1,695 IC 95 por ciento: 1,005-2,856); Cáncer (ORa 2,389 IC 95 por ciento 1,230-4,642); inmunosupresión (ORa 3,211 IC 95 por ciento 1,004-10,26); Ventilación mecánica (ORa 2,541 IC 95 por ciento 1,128-5,722); Estancia en la UCI (ORa 2,331 IC 95 por ciento1,227-4,425) e Infección por bacterias productoras de carbapenemasas (ORa 4,778 IC95 por ciento 1,313-17,38). Conclusiones: En pacientes masculinos con cáncer o cualquier otra forma de inmunosupresión, en los que se requiera el uso del ventilador mecánico o estancia en la unidad de cuidado intensivo y que además desarrollen infecciones por bacterias productoras de carbapenemasas existe mayor riesgo de muerte por agente infeccioso(AU)

Introduction: The identification of the main epidemiological clinical factors that determine the causes of mortality in hospitalized patients is a pressing need, mainly when the efforts made at present do not allow us to take actions based on the identification of the causes of the aforementioned event. Objective: To identify the prognostic factors for mortality caused by infectious agents in a high complexity hospital in the city of Cartagena, Colombia. Material and Methods: A retrospective case-control study was conducted in 86 cases and 258 control samples that met the eligibility criteria, at the 1: 3 ratio. Bivariate analyses and a subsequent multivariate analysis that included binary logistic regression methods were also performed. Results: In the multivariate analysis, the risk of mortality is determined by variables such as male sex (ORa 1,695 95 percent CI: 1.005-2.856); cancer (ORa 2,389 95 percent CI 1,230-4,642); immunosuppression (ORa 3.211 95 percent CI 1.004-10.26); mechanical ventilation (ORa 2.541 95 percent CI 1.128-5.722); stay in the ICU (ORa 2,331 95 percent CI 1,227-4,425) and infection caused by carbapenemase-producing bacteria (ORa 4,778 95 percent CI 1,313-17.38). Conclusions: Male patients with cancer or any other form of immunosuppression who require the use of a mechanical ventilator or admission to the intensive care unit who also develop infections caused by carbapenemase-producing bacteria, are at greater risk of death from an infectious agent(AU)

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Antimicrobial resistance (AR) is a problem that threatens the search for adequate safe and effective antibiotic therapy against multi-resistant bacteria like methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococci (VRE) and Clostridium difficile, among others. Daptomycin is the treatment of choice for some infections caused by Gram-positive bacteria, indicated most of the time in patients with special clinical conditions where its high pharmacokinetic variability (PK) does not allow adequate plasma concentrations to be reached. The objective of this review is to describe the data available about the type of therapeutic drug monitoring (TDM) method used and described so far in hospitalized patients with daptomycin and to describe its impact on therapeutic success, suppression of bacterial resistance, and control of side effects. The need to create worldwide strategies for the appropriate use of antibiotics is clear, and one of these is the performance of therapeutic drug monitoring (TDM). TDM helps to achieve a dose adjustment and obtain a favorable clinical outcome for patients by measuring plasma concentrations of an administered drug, making a rational interpretation guided by a predefined concentration range, and, thus, adjusting dosages individually.

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Bacillus spp. have great agricultural potential as a plant growth promoter and biocontrol agent. However, little is known concerning the bacterial molecular basis for the improvement of plant fitness. Thus, it is highly desirable to develop techniques that can contribute to the elucidation of the genetic basis for the mechanisms involved in beneficial bacterium-plant interactions. In this context, CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 is a powerful tool based on programmable molecular scissors that perform precise incisions in any DNA sequence. CRISPR-Cas9 can alter gene sequences and constitutes a cutting-edge tool to elucidate the role and function of bacterial genes associated with the benefits of plant interactions. The method described here uses a feasible CRISPR-Cas9 system in a double plasmid, one plasmid harboring the Cas9 endonuclease and the other the sgRNA, to promote gene knockout/editing in the Bacillus genus. This approach favors high efficiency in generating mutants for one or more genes in continuous or multiplex editing. Additionally, due to its universality, it can be applied to genera other than Bacillus.

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