Christian Vinueza-Burgos

From a One Health perspective, it is essential to monitor different ecological niches to identify circulating antimicrobial resistance mechanisms. Wildlife, especially birds, are considered sentinels for the identification of antimicrobial resistance genes in the environment. Thus, the aim of this study was to detect extended spectrum β-lactamases genes in Escherichia coli and Enterobacter spp. isolated from cloacal swabs of Darwin's finches (Geospiza spp.) on Santa Cruz Island in the Galapagos. A phenotypic profile of ampicillin resistance was identified in 50% (68/136) of E. coli isolates and 85.9% (177/206) in Enterobacter spp. The most prevalent gene was blaTEM, identified in E. coli (23.5%; 16/68) and Enterobacter spp. (3.9%; 7/177). The blaTEM-1B allele was observed in all E. coli isolates (100%; 16/16) and in 4 Enterobacter spp. isolates (57.1%; 4/7). Additionally, the blaTEM-116 was only identified in Enterobacter spp. (42.8%; 3/7). Furthermore, the blaSHV-148 allele was identified in one E. coli isolate. Meanwhile, Enterobacter spp. presented the blaSHV-1 (75%; 3/4) and blaSHV-11 (25%; 1/4) alleles. The blaCMY-72 and blaCTX-M genes were only observed in Enterobacter spp. isolates. The isolates with highest resistance rates were identified in the agricultural area of the Island, which may be associated with the use of antimicrobials in animal production as well as its possible presence in manure. Finally, we determined the occurrence of β-lactamase genes in Darwin finches at Santa Cruz Island for the first time. The determination of antimicrobial resistance in wild birds would allow a better understanding of AMR phenomena at the Galapagos ecosystem.

La laringotraqueítis infecciosa aviar (ILT) es una enfermedad producida por el Gallid alphaherpesvirus 1 (GaHV-1) que se transmite a través de secreciones respiratorias o fómites de aves infectadas de forma natural o por el uso de vacunas vivas originadas en embrión de pollo (CEO). El objetivo de esta investigación fue detectar molecularmente el GaHV-1 en granjas de gallinas ponedoras localizadas en la provincia de Tungurahua, Ecuador. Se trabajó con hisopados laringotraqueales y muestras de tráqueas de 47 granjas y una vacuna recombinante de uso comercial con la glicoproteína B del GaHV-1. Se encontró que 3 granjas fueron positivas a GaHV-1 al amplificarse segmentos de los genes ICP4 y timidina kinasa (TK) del virus. Por otro lado, la vacuna recombinante analizada resultó negativa a la amplificación de los genes mencionados. La amplificación de los genes ICP4 y TK en las muestras de campo demostró la presencia del GaHV-1 en la provincia, pero se descartó la posibilidad de que se trate de virus vacunal derivado del uso de la vacuna recombinante autorizada para ser usada en la zona de estudio. Dado que las aves no presentaron signos clínicos relacionados con ILT se determinó que no se podría hablar de un brote de la enfermedad, pero se requiere un estudio molecular de secuenciación de genoma completo para obtener resultados concluyentes. No obstante, debería evitarse la utilización de vacunas tipo CEO en los calendarios vacunales en la provincia de Tungurahua y continuar sólo con el uso de las vacunas vectorizadas autorizadas por el ente de control nacional.

Thermotolerant Campylobacter is an important zoonotic pathogen known for causing gastroenteritis in humans, with poultry as its primary reservoir. A total of 468 samples were collected, of which 335 were chicken carcass samples (representing the food component), and 133 were chicken caeca samples (representing the animal component). These samples underwent culture, with colonies examined under a microscope. Species identification was achieved through multiplex PCR. Additionally, antimicrobial susceptibility profiles were determined using the Kirby-Bauer method, testing for sensitivity to gentamicin, ciprofloxacin, tetracycline, and erythromycin. Additionally, 55 C. jejuni (62.5%) and 33 C. coli (37.5%) isolates were selected for whole genome sequencing (WGS). A High prevalence of Campylobacter was observed, with rates of 95.5% (n = 127, CI_95%: 92.5% - 98.5%) in the animal component and 72.5% (n = 243, CI_95%: 69.9% - 75.1%) in the food component. Specifically, C. jejuni was detected in 33.1% (n = 42) of poultry farms and 38.3% (n = 93) of chicken carcasses, while C. coli was found in 64.6% (n = 82) of poultry farms and 60.5% (n = 147) of chicken carcasses. Antimicrobials with the highest rates of resistance (67%-100%) were ciprofloxacin and tetracycline, in both animal and food component isolates. Erythromycin resistance was notable, ranging from 22% to 33%, with only two C. jejuni isolates from retail were resistant to gentamicin. Furthermore, multidrug resistance was identified in 23% (20 isolates) of the Campylobacter isolates. Genetic analysis revealed the presence of fourteen resistance genes in both C. jejuni and C. coli isolates, including tet(O), bla_OXA-460, bla_OXA-184, bla_OXA-489, bla_OXA-193, bla_OXA-784, bla_OXA-603, aph(3’)-IIIa, aad9, aph(2’’)-If, aadE-Cc, sat4, and ant(6)-Ia. Additionally, twenty-five plasmids were detected in the 88 Campylobacter isolates examined. Interestingly, most isolates also harbored genes encoding putative virulence factors associated with pathogenicity, invasion, adherence, and production of cytolethal distending toxin (cdt): cheV, cheA, cheW, cheY, flaA, flgR, flaC, flaD, flgB, flgC, ciaB, ciaC. The WGS analysis showed the presence of several cgSTs in both animal and food components, with nine of them widely disseminated between components. Moreover, C. coli and C. jejuni isolates from different sources presented less than 11 single nucleotide polymorphisms (SNPs), suggesting clonality (16 isolates). Further analysis using SNP tree demonstrated widespread distribution of certain C. jejuni and C. coli clones across multiple farms and retail stores. This study presents, for the first-time, insights into the clonality, plasmid diversity, virulence, and antimicrobial resistance (AMR) of thermotolerant Campylobacter strains originating from the Ecuadorian poultry industry. The identification of AMR genes associated with the main antibiotics used in the treatment of campylobacteriosis in humans, highlights the importance of the prudent use of antimicrobials in the poultry industry. Additionally, this research remarks the need for regional studies to understand the epidemiology of this pathogen.

La bacteria Escherichia coli causa la colibacilosis en animales de granja que actúan como reservorios de cepas patógenas. La resistencia antimicrobiana de E. coli productor de betalactamasas de espectro extendido [BLEE] es un grave problema de salud pública y se puede atribuir a factores relacionados con el consumo de alimentos y el contacto con animales domésticos. El objetivo de este estudio fue determinar la presencia y patrones de resistencia antimicrobiana de E. coli BLEE aislado en muestras fecales provenientes de bovinos productores de leche de la provincia de Pichincha. Se analizaron un total 182 muestras de heces de bovinos: 112 muestras de bovinos faenados en el Camal Metropolitano de la provincia de Pichincha y 70 muestras de la colección de la Unidad de Investigación de Enfermedades Transmitidas por Alimentos y Resistencias a los Antimicrobianos [UNIETAR], se realizó el aislamiento de E. coli BLEE, la identificación bioquímica y pruebas de resistencia a los principales antibióticos utilizados. Se logró identificar 93 muestras positivas a E. coli BLEE (51 %), el análisis fenotípico reveló que los antibióticos amoxicilina más ácido clavulánico, cefepime, ceftazidima, ciprofloxacina, amikacina y tetraciclina presentaron porcentajes de resistencia mayores al 80 %. Además, se observó una baja resistencia a la nitrofurantoína, cefoxitin y ertapenem, mientras que ningún aislado fue resistente a la tigeciclina. El 100 % de los aislados presentaron fenotipos de multirresistencia y el patrón más frecuente estuvo compuesto por 7 familias de antibióticos. En conclusión, estos resultados sugieren que E. coli originaria de bovinos lecheros podría ser un reservorio de genes BLEE.

Background Salmonella enterica are bacteria that include more than 2,500 serovars. Most of these serovars have been linked to human foodborne illnesses, mainly related to poultry and pigs. Thus, these animals are considered the reservoirs of many Salmonella serovars and strains related to antibiotic resistance. This study aimed to determine the prevalence, serovars, β-lactam resistance genes, and the risk factors associated with Salmonella enterica in pork commercialized in open markets of Quito city. Methods For this, 165 pork meat samples were taken from municipal markets in three areas in the city. These samples were microbiologically processed following the ISO 6579-2014 standardized method. The polymerase chain reaction (PCR) test was used to identify Salmonella serotyping and resistance genes. Strains not identified by PCR were typed by the Kauffman White Le Minor scheme. A multivariate analysis was performed to identify risk factors associated with the presence of the microorganism. Results Salmonella prevalence in pork was 9.1%. Identified serovars were 4, [5], 12: i:- (53.3%), Infantis (33.3%), and Derby (13.4%). Furthermore, the β-lactam resistance genes bla CTX-M-65 could be identified in three S. infantis isolates. Multivariate analysis showed that temperature (above 8°C) and cutting surfaces (wood) presented significant association values. Conclusions In conclusion, pork in traditional markets of Quito is contaminated with Salmonella enterica, whose main serovars pose a public health concern, and shows beta-lactam resistance.

Background Salmonella enterica are bacteria that include more than 2,500 serovars. Most of these serovars have been linked to human foodborne illnesses, mainly related to poultry and pigs. Thus, these animals are considered the reservoirs of many Salmonella serovars and strains related to antibiotic resistance. This study aimed to determine the prevalence, serovars, β-lactam resistance genes, and the risk factors associated with Salmonella enterica in pork commercialized in open markets of Quito city. Methods For this, 165 pork meat samples were taken from municipal markets in three areas in the city. These samples were microbiologically processed following the ISO 6579-2014 standardized method. The polymerase chain reaction (PCR) test was used to identify Salmonella serotyping and resistance genes. Strains not identified by PCR were typed by the Kauffman White Le Minor scheme. A multivariate analysis was performed to identify risk factors associated with the presence of the microorganism. Results Salmonella prevalence in pork was 9.1%. Identified serovars were 4, [5], 12: i:- (53.3%), Infantis (33.3%), and Derby (13.4%). Furthermore, the β-lactam resistance genes bla CTX-M-65 could be identified in three S. infantis isolates. Multivariate analysis showed that temperature (above 8°C) and cutting surfaces (wood) presented significant association values. Conclusions In conclusion, pork in traditional markets of Quito is contaminated with Salmonella enterica, whose main serovars pose a public health concern, and shows beta-lactam resistance.

Background: Salmonella enterica are bacteria that include more than 2,500 serovars. Most of these serovars have been linked to human foodborne illnesses, mainly related to poultry and pigs. Thus, these animals are considered the reservoirs of many Salmonella serovars and strains related to antibiotic resistance. This study aimed to determine the prevalence, serovars, β-lactam resistance genes, and the risk factors associated with Salmonella enterica in pork commercialized in open markets of Quito city. Methods: For this, 165 pork meat samples were taken from municipal markets in three areas in the city. These samples were microbiologically processed following the ISO 6579-2014 standardized method. The polymerase chain reaction (PCR) test was used to identify Salmonella serotyping and resistance genes. Strains not identified by PCR were typed by the Kauffman White Le Minor scheme. A multivariate analysis was performed to identify risk factors associated with the presence of the microorganism. Results: Salmonella prevalence in pork was 9.1%. Identified serovars were 4, [5], 12: i:- (53.3%), Infantis (33.3%), and Derby (13.4%). Furthermore, the β-lactam resistance genes bla CTX-M-65 could be identified in three S. infantis isolates. Multivariate analysis showed that temperature (above 8°C) and cutting surfaces (wood) presented significant association values. Conclusions: This research represents the first report of several epidemiological aspects of Salmonella in pork in Ecuador.