Daphne Ramos Delgado

Background: Pigs and cattle have been implicated as reservoirs of antimicrobial resistance genes (ARGs) that can spread to humans, and houseflies are considered potential carriers of bacteria with ARGs that could contribute to their spread to the environment, including food, animals, and humans. Methods: In this study, 107, 145, and 127 Escherichia coli strains were isolated from houseflies, pigs, and cattle, respectively, from a slaughterhouse in Lima, Peru. Antimicrobial susceptibility testing was performed using the Kirby–Bauer method, where thirteen antibiotics were used. Strains were also plated on CHROMagar COL-APSE agar, and colistin’s minimum inhibitory concentration (MIC) was determined. Colistin-resistant E. coli strains were subjected to whole genome sequencing. Results: 7.8% (8/107), 1.38% (2/145), and 0.79% (1/127) of E. coli strains isolated from houseflies, pigs, and cattle, respectively, were resistant to colistin (MIC ≥ 4 µg/mL). ARGs associated with resistance to more than 6 different antibiotic classes were identified, including tetracyclines, beta-lactams, fluoroquinolones, nitroimidazoles, trimethoprim and amphenicols. Conclusions: This study suggests that flies could contribute to the dissemination of ARG carrying bacteria and shows the potential risk of animals and meat production systems as reservoirs of ARG carrying bacteria.

This study evaluates the effects of dietary lipid levels on growth performance, hematological health, and muscle composition of juvenile Arapaima gigas. We tested five isonitrogenous diets (451.7 g kg⁻¹ of crude protein) with increasing lipid levels (6%, 10%, 14%, 18%, and 22%). A total of 600 juvenile A. gigas (80.0 ± 10.5 g; 21.8 ± 1.0 cm) were distributed into 20 tanks (500 L; n = 4; 30 fish per tank) in an indoor open system. The fish were fed to apparent satiety four times daily for 60 days. As dietary lipid levels increased, all growth parameters and lipid content in both the whole body and muscle declined. The diet containing 6% lipids resulted in the maximum final weight, weight gain, feed intake, and the lowest feed conversion rate. However, a maximum lipid level of up to 10.26%, with a gross energy-to-protein ratio of 10.15 kcal g⁻¹ in the diet, as determined through polynomial regression analysis, can be used for juvenile A. gigas without significantly affecting weight gain. Diets with high lipid content (18% and 22% lipids) resulted in the lowest survival rates, highest feed conversion rates, lowest condition factor, visible skeletal protrusions, scale depigmentation, and impaired blood biochemistry. The content of eicosapentaenoic acid, docosahexaenoic acid, n-3, and the n-3:n-6 ratio increased in the muscle lipid fraction (mg g⁻¹ of total lipids) in response to higher dietary lipid levels; however, this does not represent an overall improvement in the meat quality, since the total lipid content in the muscle (g of lipid per 100 g of muscle) was reduced due to impaired growth in fish fed high-lipid diets. Notably, the experimental diets also differed in fatty acid composition, which may have influenced some of the physiological and compositional responses observed. Diets with 6% lipids are recommended to provide optimal growth performance, and a maximum dietary lipid level of up to 10.26% is advised to ensure successful A. gigas farming without impairing weight gain.

El objetivo del estudio fue evaluar la actividad antimicrobiana del aceite esencial de orégano (Origanum vulgare) frente a Staphylococcus aureus ATCC 25923 en carne de pollo. Se determinó la concentración mínima inhibitoria (CMI) mediante el método de microdilución en pocillos y la concentración mínima bactericida (CMB) para determinar la supervivencia de las bacterias expuestas a diferentes concentraciones del aceite esencial. Además, se evaluó la capacidad del aceite esencial de orégano de inhibir el crecimiento de S. aureus en filetes de pollo. Se obtuvo una CMI de 0.5% y una CMB de 4%. Las concentraciones ≥1% de aceite esencial de orégano redujeron significativamente (pS. aureus en la carne de pollo, en niveles relacionados directamente con la concentración aplicada. Los resultados demostraron que el aceite de orégano posee un efecto antimicrobiano contra S. aureus ATCC 25923.

Peru is currently one of the world’s leading culinary destinations, whose world-renowned cuisine uses vegetables, mainly lettuce, as frequent ingredients. Vegetable consumption is promoted worldwide as a part of a healthy diet. However, vegetables, more frequently lettuce, have been implicated as a vehicle of infection for several foodborne parasites. This study aimed to determine the presence of potentially pathogenic parasites in lettuce marketed in the Central Andes of Peru. A total of 75 lettuce samples were collected from the two largest wholesale markets and the main open-air market in Jauja province, in the central Peruvian Andes. The province of provenance (coast vs. highlands), lettuce variety (“curly-leaf”, “iceberg”, and “butter”), and type of market were recorded. The samples were microscopically examined for detection of parasitic life forms using standard parasitological methods including direct slide smear, Lugol’s iodine staining, and Modified Ziehl–Neelsen staining. The overall positivity of parasitic contamination in lettuces was 45.3% (CI 95%: 34–56.6%). Cryptosporidium spp., Isospora belli, Giardia lamblia, Balantidium coli, and Entamoeba spp. were detected in twenty-six (34.7%), six (8%), four (5.3%), two (2.7%), and two (2.7%) lettuces, respectively. I. belli was found in a significantly (p < 0.01) lower proportion in the “butter” variety, and significantly (p < 0.05) higher contamination with G. lamblia was found in lettuce sold at the open-air market. B. coli, G. lamblia, and E. histolytica/E. dispar/E. moshkovskii were detected only in lettuce from the highlands (Tarma province). This study provides important data for health authorities to develop food safety programs. This information is also of interest to the international community because of the increased visibility that Peru has gained as a tourist destination.

El objetivo del estudio fue evaluar el efecto de la aplicación de oleorresina de Capsicum chinense sobre el crecimiento bacteriano en carne de res empacada al vacío y refrigerada. La oleorresina se extrajo con etanol y la capsaicina y dihidrocapsaicina se cuantificaron mediante HPLC con detector de arreglo de diodos. Se constituyeron dos grupos (G1 y G2) que consistían en cortes de carne (50 g): G1 con aplicación de 2.5 ml de la oleorresina en toda la superficie de cada corte, y G2 grupo control. Los cortes de carne fueron empacados al vacío y se almacenaron en refrigeración. Se retiraron tres muestras de cada grupo los días 0, 1, 15, 30, 45, 60, 75 y 90 de almacenamiento para medición de pH y para el recuento de aerobios mesófilos totales, aerobios psicrótrofos totales, bacterias ácido-lácticas y Brochothrix thermosphacta. El rendimiento de oleorresina fue 12.53 ± 0.30%. La concentración de capsaicina y dihidrocapsaicina en la oleorresina fue de 1.39 y 0.54 mg/g, respectivamente. El pH en G1 se mantuvo en niveles adecuados por más días y los recuentos bacterianos fueron menores que en G2-control. Bajo las condiciones de estudio, se determinó que la vida útil para G1 fue de 70 días, mientras que para G2 fue de 56 días. Se concluye que la oleorresina de Capsicum chinense aplicada a carne de res empacada al vacío y refrigerada prolonga su vida útil.

El objetivo del estudio fue determinar el periodo de retiro de enrofloxacina en cuyes (Cavia porcellus). Se utilizaron 51 cuyes (25 hembras y 26 machos) de la raza Perú de una granja ubicada en el distrito de Maranganí (Cusco, Perú). Para ello, se administró enrofloxacina al 10%, vía oral, a razón de 10 mg/kg (0.1 ml/kg PV) cada 24 horas por un periodo de 10 días. Inmediatamente después de la última administración del antibiótico (hora 0), tres cuyes fueron seleccionados en forma aleatoria y sacrificados cada dos horas hasta las 32 horas del retiro del fármaco, tomándose muestras del músculo diafragma. El análisis y cuantificación de los residuos del antibiótico en el diafragma se realizó empleando el kit comercial Max Signal® Enrofloxacin ELISA Kit. La concentración máxima de enrofloxacina (1425 ± 53.4 µg/kg) se determinó a las 12 horas del retiro, descendiendo hasta 80.8 ± 6 µg/kg a las 28 h, valor por debajo de 100 µg/kg considerado como límite máximo de referencia. Bajo las condiciones de este estudio, se sugiere un periodo de retiro de dos días para cuyes tratados con enrofloxacina.

El objetivo del estudio fue detectar genes de resistencia a β-lactámicos de espectro extendido (BLEE) procedentes de enterobacterias aisladas en muestras de carne de pollo obtenidas en mercados de abasto del distrito de Santiago de Surco, Lima, Perú. Se obtuvieron 34 muestras para el procedimiento microbiológico. El aislamiento se realizó utilizando agar EMB y TSA. Para la caracterización bioquímica de género y especie se utilizó el kit EnteroPluri-Test® Liofilchem. El análisis de susceptibilidad antimicrobiana se realizó con el método Kirby-Bauer como cribado y el método de Jarlier para la confirmación. Las enterobacterias confirmadas fueron evaluadas mediante diagnóstico molecular para genes de resistencia a β-lactámicos de espectro extendido. El PCR en punto final se utilizó para la amplificación de genes CTX-M-1, CTX-M-2 y CTX-M-9, y un PCR dúplex en punto final para la amplificación de genes TEM y SHV. Se identificaron 34 cepas de enterobacterias, siendo 20/34 sospechosas de producir enzimas BLEE bajo el método Kirby-Bauer, y 12/34 cepas confirmadas de producir BLEE bajo el método de Jarlier. Las enterobacterias fueron Salmonella choleraesuis (n=1), Escherichia coli (n=8), Serratia odorifera (n=1) y Klebsiella ozaenae (n=2). La identificación de cepas multidrogoresistentes (MDR) fue de 13/34, siendo E. coli (n=8), Klebsiella ozaenae (n=3), Serratia odorifera (n=1) y Salmonella choleraesuis (n=1). Todas (12/12) las cepas fenotípicamente resistentes para BLEE fueron positivas a la detección de genes BLEE. La mayor frecuencia correspondió al gen CTX-M-1 (12/12), seguido del gen TEM (10/12) y el gen CTX-M-9 (2/12). No se detectaron genes CTX-M-2 ni SHV_. Se concluye que la carne de pollo vendida por mercados de abasto del distrito de Santiago de Surco contiene enterobacterias (BLEE) con al menos un gen de resistencia.

The contamination of the surface water of lagoons is a common problem in developing countries, and can affect fishing activities. A case study was conducted on water quality and microbiological contamination of the fishing marketing chain in the Peruvian Amazon (Laguna de Yarinacocha). The microbiological, physical–chemical and parasitological parameters of the surface water were evaluated in three points of the lagoon near the landing stage; and microbiological parameters of facilities, handlers and three species of fish (Prochilodus nigricans, Mylossoma duriventre and Siluriforme spp.). In the water, there were coliform counts ≥ 23 (Most probable number—MPN)/100 mL, Escherichia coli ≥ 3.6 MPN/100 mL, and Pseudomona spp. up to 2.2 MPN/100 mL; high turbidity and variable amounts of parasites. In facilities and handlers, high levels of coliforms, mainly Escherichia coli, and Staphylococcus aureus and Escherichia coli, were found in M. duriventre meat. A poor quality of the surface water of the lagoon is concluded that compromises part of the fishing marketing chain, mainly facilities and manipulators. Furthermore, the levels of Staphylococcus aureus and Escherichia coli in fish meat show poor handling practices and possible risk of contamination by water sources.

The aim of this study was to determine the profile of antibiotic resistance of isolated Salmonella enterica strains during the slaughtering process of pigs in a slaughterhouse in Lima. Strains of Salmonella enterica (n=148) isolated from stool samples and mesenteric ganglia of pigs were used. The evaluation of antibiotic resistance was performed by the disc diffusion method (Kirby-Bauer). Thirteen antibiotics of frequent use in human medicine were considered, of which most of them are also used in pigs as prophylactic and growth promoters. All strains showed resistance to tetracycline and all showed sensitivity to ciprofloxacin. Likewise, all strains were resistant to at least one antibiotic.