Comparative analysis of the antimicrobial activity of larval secretions and excretions from Calliphora vicina and Sarconesiopsis magellanica (Diptera: Calliphoridae) / Análisis comparativo de la actividad antimicrobiana de secreciones y excreciones larvales de Calliphora vicina y Sarconesiopsis magellanica (Diptera: Calliphoridae)

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.

Análisis comparativo de la actividad antimicrobiana de secreciones y excreciones larvarias de Calliphora vicina y Sarconesiopsis magellanica (Diptera: Calliphoridae) / A comparative analysis of Calliphora vicina and Sarconesiopsis magellanica (Diptera: Calliphoridae) larval secretions and excretions antimicrobial activity

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.

Reduced levels of convalescent neutralizing antibodies against SARS-CoV-2 B.1+L249S+E484K lineage.

The E484K mutation at the SARS-CoV-2 Spike protein emerged independently in different variants around the world and has been widely associated with immune escape from neutralizing antibodies generated during previous infection or vaccination. In this work, the B.1 + L249S+E484K lineage was isolated along with A.1, B.1.420, and B.1.111 SARS-CoV-2 lineages without the E484K mutation and the neutralizing titer of convalescent sera was compared using microneutralization assays. While no significant differences in the neutralizing antibody titers were found between A.1 and B.lineages without the E484K mutation, the neutralizing titers against B.1 + L249S+E484K were 1.5, 1.9, 2.1, and 1.3-fold lower than against A.1, B.1.420, B.1.111-I, and B.1.111-II, respectively. However, molecular epidemiological data indicate that there is no increase in the transmissibility rate associated with this new lineage. This study supports the capability of new variants with the E484K mutation to be resistant to neutralization by humoral immunity, and therefore the need to intensify surveillance programs to determine if these lineages represent a risk for public health.

Risk factors for triatominae infestation in a municipality of Colombia.

BACKGROUND: Identifying risk factors for Triatominae infestation is essential for the development of vector control interventions. METHODS: To determine the intra- and peridomiciliary risk factors associated with triatomine infestation, a cross-sectional analytical study was carried out with random cluster sampling in two stages, which included the identification of risk factors by survey and direct observation, as well as the search and capture of triatomines. The detection of trypanosomes in triatomines was carried out by observing the rectal content and then by conventional polymerase chain reaction (PCR). RESULTS: In 21 of the 207 houses inspected, 13 specimens of R. colombiensis and 19 specimens of P. geniculatus were found. Entomological indices included: dispersion 36%, infestation 10%, infection 65%, colonization 4.7%, density 15%, and concentration 152%. An association was found between the presence of Triatominae and the existence of branches and fissures in the floors, as well as with the presence of accumulated objects and with knowledge about Chagas disease. The risk of having triatomines in urban homes is 5.7 times higher than the risk in rural areas [confidence interval (CI) 0.508-67.567]; 6.6 times in houses with cracked soil (CI 0.555-81.994), 6 times in houses located near caneys (CI 0.820-44.781), and 6.16 times with accumulated objects (CI 1.542-39.238). CONCLUSION: Chagas disease is a complex problem that requires control based on the vector's elimination or surveillance, which implies identifying species and their distribution, generating alerts, knowledge, and awareness in the population. It is necessary to intensify surveillance activities for the event, especially in changing aspects of Chagas diseases' transmission dynamics, such as urbanization and the type of housing associated with the vector's presence.

New Δ-tocotrienol derivatives from Colombian propolis.

Two new δ-tocotrienol derivatives with oxidized terminal chain: 5,6-dioxo-garcinoic acid (trans-13'-carboxy-5,6-dioxo-δ-tocotrienol) (2) and 5-hydroxy-8b-oxo garcinoic acid (trans-13'-carboxy-5-hydroxy-8b-oxo-δ-tocotrienol) (3), together with one known derivative garcinoic acid (trans-13'-carboxy-δ-tocotrienol) (1) were isolated from a Colombian propolis. Garcinoic acid was found as a propolis constituent for the first time. The isolated compounds and crude ethanolic extract demonstrated high antimicrobial activity against Staphylococcus aureus and Candida albicans (MICs range: 10-39 µg/ml) as well as promising antioxidant potential in DPPH assay. Compound 3 displayed highest radical scavenging activity, even higher than that of dl-α-tocopherol, used as a positive control.

Sarconesin II, a New Antimicrobial Peptide Isolated from Sarconesiopsis magellanica Excretions and Secretions.

Antibiotic resistance is at dangerous levels and increasing worldwide. The search for new antimicrobial drugs to counteract this problem is a priority for health institutions and organizations, both globally and in individual countries. Sarconesiopsis magellanica blowfly larval excretions and secretions (ES) are an important source for isolating antimicrobial peptides (AMPs). This study aims to identify and characterize a new S. magellanica AMP. RP-HPLC was used to fractionate ES, using C18 columns, and their antimicrobial activity was evaluated. The peptide sequence of the fraction collected at 43.7 min was determined by mass spectrometry (MS). Fluorescence and electronic microscopy were used to evaluate the mechanism of action. Toxicity was tested on HeLa cells and human erythrocytes; physicochemical properties were evaluated. The molecule in the ES was characterized as sarconesin II and it showed activity against Gram-negative (Escherichia coli MG1655, Pseudomonas aeruginosa ATCC 27853, P. aeruginosa PA14) and Gram-positive (Staphylococcus aureus ATCC 29213, Micrococcus luteus A270) bacteria. The lowest minimum inhibitory concentration obtained was 1.9 µM for M. luteus A270; the AMP had no toxicity in any cells tested here and its action in bacterial membrane and DNA was confirmed. Sarconesin II was documented as a conserved domain of the ATP synthase protein belonging to the Fli-1 superfamily. The data reported here indicated that peptides could be alternative therapeutic candidates for use in infections against Gram-negative and Gram-positive bacteria and eventually as a new resource of compounds for combating multidrug-resistant bacteria.

Sarconesin II, a new antimicrobial peptide isolated from Sarconesiopsis magellanica excretions and secretions

Antibiotic resistance is at dangerous levels and increasing worldwide. The search for new antimicrobial drugs to counteract this problem is a priority for health institutions and organizations, both globally and in individual countries. Sarconesiopsis magellanica blowfly larval excretions and secretions (ES) are an important source for isolating antimicrobial peptides (AMPs). This study aims to identify and characterize a new S. magellanica AMP. RP-HPLC was used to fractionate ES, using C18 columns, and their antimicrobial activity was evaluated. The peptide sequence of the fraction collected at 43.7 min was determined by mass spectrometry (MS). Fluorescence and electronic microscopy were used to evaluate the mechanism of action. Toxicity was tested on HeLa cells and human erythrocytes; physicochemical properties were evaluated. The molecule in the ES was characterized as sarconesin II and it showed activity against Gram-negative (Escherichia coli MG1655, Pseudomonas aeruginosa ATCC 27853, P. aeruginosa PA14) and Gram-positive (Staphylococcus aureus ATCC 29213, Micrococcus luteus A270) bacteria. The lowest minimum inhibitory concentration obtained was 1.9 µM for M. luteus A270; the AMP had no toxicity in any cells tested here and its action in bacterial membrane and DNA was confirmed. Sarconesin II was documented as a conserved domain of the ATP synthase protein belonging to the Fli-1 superfamily. The data reported here indicated that peptides could be alternative therapeutic candidates for use in infections against Gram-negative and Gram-positive bacteria and eventually as a new resource of compounds for combating multidrug-resistant bacteria.

Sarconesin II, a new antimicrobial peptide isolated from Sarconesiopsis magellanica excretions and secretions

Antibiotic resistance is at dangerous levels and increasing worldwide. The search for new antimicrobial drugs to counteract this problem is a priority for health institutions and organizations, both globally and in individual countries. Sarconesiopsis magellanica blowfly larval excretions and secretions (ES) are an important source for isolating antimicrobial peptides (AMPs). This study aims to identify and characterize a new S. magellanica AMP. RP-HPLC was used to fractionate ES, using C18 columns, and their antimicrobial activity was evaluated. The peptide sequence of the fraction collected at 43.7 min was determined by mass spectrometry (MS). Fluorescence and electronic microscopy were used to evaluate the mechanism of action. Toxicity was tested on HeLa cells and human erythrocytes; physicochemical properties were evaluated. The molecule in the ES was characterized as sarconesin II and it showed activity against Gram-negative (Escherichia coli MG1655, Pseudomonas aeruginosa ATCC 27853, P. aeruginosa PA14) and Gram-positive (Staphylococcus aureus ATCC 29213, Micrococcus luteus A270) bacteria. The lowest minimum inhibitory concentration obtained was 1.9 µM for M. luteus A270; the AMP had no toxicity in any cells tested here and its action in bacterial membrane and DNA was confirmed. Sarconesin II was documented as a conserved domain of the ATP synthase protein belonging to the Fli-1 superfamily. The data reported here indicated that peptides could be alternative therapeutic candidates for use in infections against Gram-negative and Gram-positive bacteria and eventually as a new resource of compounds for combating multidrug-resistant bacteria.

Trypanosoma cruzi infection in naturally infected dogs from an endemic region of Cundinamarca, Colombia.

The seropositivity and risk factors for Trypanosoma cruzi infection in dogs from a municipality of Cundinamarca, a central state of Colombia were studied. A total of 356 client-owned dogs from urban, peri-urban and rural areas of La Mesa municipality, (Cundinamarca, Colombia) were randomly selected. Blood samples were collected by venipuncture. Anti-T. cruzi antibodies were determined using the enzyme-linked immunosorbent assay (ELISA) method. Reactive ELISA sera were processed by indirect immunofluorescence to confirm the presence of anti-T. cruzi antibodies. Chi-square tests were conducted for statistical analysis. Serologic tests for T. cruzi infection showed a prevalence of 29.49% (105/356), the rural area show a highest T. cruzi infection pattern in comparison with the other zone locations. Two triatomine species were found through the study: Panstrongylus geniculatus (53.4%) and Rhodnius colombiensis (46.6%). The prevalence of positive vectors for parasite was of 52.1% (38/73). Additionally, a very close relation between triatomine bugs and dogs in the rural zone (1:3.1) was observed. These results are the first report of natural infection by T. cruzi in domestic dogs in La Mesa municipality. In conclusion, the presence of anti-T. cruzi antibodies in dogs in this area suggest vector transmission. There is a need for active surveillance programs throughout the La Mesa municipality and vector control strategies should also be implemented.

Pseudomonas aeruginosa: an emerging nosocomial trouble in veterinary / Pseudomonas aeruginosa: un problema nosocomial emergente en veterinaria

Objective. The goal of this study was to evaluate the susceptibility pattern of isolates P. aeruginosa from veterinary clinical centers in Bogotá, D.C., to some commonly used antibiotics in clinical. Materials and methods. Bacteriological standard protocols were used for the isolation and identification of bacterial strains. To evaluate the antimicrobial susceptibility of the isolates, to commonly used antibiotics, was performed the Kirby-Bauer agar-disk diffusion method on Mueller-Hinton agar. Results. A total of 160 samples was taken from clinical specimens and the environment in different veterinary clinics. Out of these samples, 89 (55.6%) were gram-negative strains, of which ten strains of P. aeruginosa were isolated (11.2%). All strains were resistant to Cefazolin, Lincomycin, Cephalothin, Ampicillin, Clindamycin, Sulfamethoxazole-Trimethoprim and Chloramphenicol while some isolates exhibited either resistance or an intermediate response to Amikacin (30%), Gentamicin (30%), Tobramycin (10%), Ciprofloxacin (20%), Ceftazidime (30%), Erythromycin (100%), Tetracycline (100%), Imipenem (10%), Meropenem (90%) and Bacitracin (90%). Conclusions. The results demonstrate that the acquired antimicrobial resistances of P. aeruginosa strains depend on antibiotic protocols applied. As observed in human hospitals, Pseudomonas aeruginosa is acting as one of the multidrug-resistant microorganisms of veterinary clinical relevance.

Objetivo. Evaluar el comportamiento a algunos antibióticos de uso común en clínica de cepas de Pseudomonas aeruginosa aisladas de centros clínicos veterinarios en Bogotá, D.C. Materiales y métodos. Un protocolo bacteriológico estándar se utilizó para el aislamiento e identificación de cepas bacterianas. Para evaluar la sensibilidad de los aislamientos bacterianos a diferentes antimicrobianos de uso clínico común, se empleó el método de difusión sobre agar Mueller-Hinton de Kirby-Bauer. Resultados. Un total de 160 muestras fueron tomadas a partir de muestras clínicas y del ambiente de diferentes clínicas veterinarias de la ciudad de Bogotá. De estas muestras, 89 (55.6%) fueron cepas bacterianas gram-negativas, de las que se aislaron 10 cepas de P. aeruginosa (11.2%). Todas las cepas de P. aeruginosa mostraron resistencia a la Cefazolina, Lincomicina, Cefalotina, Ampicilina, Clindamicina, Trimetoprim- Sulfametoxazol y Cloranfenicol; mientras que algunas de éstas, mostraron resistencia o una respuesta intermedia a Amikacina (30%), Gentamicina (30%), Tobramicina (10%), Ciprofloxacina (20%), Ceftazidima (30%), Eritromicina (100%), Tetraciclina (100%), Imipinem (10%), Meropenem (90%) y Bacitracina (90%). Conclusiones. Los resultados demuestran que la resistencia adquirida a los antimicrobianos en las cepas de P. aeruginosa aisladas de estos centros clínicos depende de los protocolos antibióticos aplicados. Al igual que sucede en los nosocomios Humanos, Pseudomonas aeruginasa se está comportando como uno de los microorganismos multirresistetes de relevancia clínica causante de infecciones nosocomiales veterinarias.