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1. Genomic and Phylogenomic Characterization of Carbapenem-resistant Pseudomonas aeruginosa ‘High-risk’ Clone O4/ExoS+/ST654 Circulating in Chilean Hospitals

Author

Opazo-Capurro, Andrés, Aguilar-Vera, Omar Alejandro, González-Muñoz, Paulina, Amsteins-Romero, Luis, Quiroga, Monserrat, Encina, Antonia, Herrera-Chávez, Néstor, Quezada-Aguiluz, Mario, Aguayo-Reyes, Alejandro, Morales-León, Felipe, Illesca, Vijna, Vera, Rodrigo, Salgado, Fabiola, Suazo, Patricio, Fuenzalida, Luz María, Bello-Toledo, Helia, Castillo-Ramírez, Santiago, and González-Rocha, Gerardo

Published
2024
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5. Isolation and Characterization of Lytic Bacteriophages Capable of Infecting Diverse Multidrug-Resistant Strains of Pseudomonas aeruginosa : PaCCP1 and PaCCP2.

Author

Parra, Boris, Sandoval, Maximiliano, Arriagada, Vicente, Amsteins, Luis, Aguayo, Cristobal, Opazo-Capurro, Andrés, Dechesne, Arnaud, and González-Rocha, Gerardo

Subjects
SOFT tissue infections, SEWAGE disposal plants, DRUG resistance in microorganisms, PSEUDOMONAS aeruginosa, BACTERIAL diseases
Abstract

Background/Objectives: Antimicrobial resistance (AMR) is a major public health threat, which is exacerbated by the lack of new antibiotics and the emergence of multidrug-resistant (MDR) superbugs. Comprehensive efforts and alternative strategies to combat AMR are urgently needed to prevent social, medical, and economic consequences. Pseudomonas aeruginosa is a pathogen responsible for a wide range of infections, from soft tissue infections to life-threatening conditions such as bacteremia and pneumonia. Bacteriophages have been considered as a potential therapeutic option to treat bacterial infections. Our aim was to isolate phages able to infect MDR P. aeruginosa strains. Methods: We isolated two lytic phages, using the conventional double layer agar technique (DLA), from samples obtained from the influent of a wastewater treatment plant in Concepción, Chile. The phages, designated as PaCCP1 and PaCCP2, were observed by electron microscopy and their host range was determined against multiple P. aeruginosa strains using DLA. Moreover, their genomes were sequenced and analyzed. Results: Phage PaCCP1 is a member of the Septimatrevirus genus and phage PaCCP2 is a member of the Pbunavirus genus. Both phages are tailed and contain dsDNA. The genome of PaCCP1 is 43,176 bp in length with a GC content of 54.4%, encoding 59 ORFs, one of them being a tRNA gene. The genome of PaCCP2 is 66,333 bp in length with a GC content of 55.6%, encoding 102 non-tRNA ORFs. PaCCP1 is capable of infecting five strains of P. aeruginosa, whereas phage PaCCP2 is capable of infecting three strains of P. aeruginosa. Both phages do not contain bacterial virulence or AMR genes and contain three and six putative Anti-CRISPR proteins. Conclusions: Phages PaCCP1 and PaCCP2 show promise as effective treatments for MDR P. aeruginosa strains, offering a potential strategy for controlling this clinically important pathogen through phage therapy. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Co-Occurrence of Two Plasmids Encoding Transferable bla NDM-1 and tet (Y) Genes in Carbapenem-Resistant Acinetobacter bereziniae.

Author

Opazo-Capurro, Andrés, Xanthopoulou, Kyriaki, Arazo del Pino, Rocío, González-Muñoz, Paulina, Matus-Köhler, Maximiliano, Amsteins-Romero, Luis, Jerez-Olate, Christian, Hormazábal, Juan Carlos, Vera, Rodrigo, Aguilera, Felipe, Fuller, Sebastián, Higgins, Paul G., and González-Rocha, Gerardo

Subjects
HORIZONTAL gene transfer, WHOLE genome sequencing, COVID-19 pandemic, THIRD generation cephalosporins, CARBAPENEM-resistant bacteria, CARBAPENEMS
Abstract

Acinetobacter bereziniae has emerged as a significant human pathogen, acquiring multiple antibiotic resistance genes, including carbapenemases. This study focuses on characterizing the plasmids harboring the blaNDM-1 and tet(Y) genes in two carbapenem-resistant A. bereziniae isolates (UCO-553 and UCO-554) obtained in Chile during the COVID-19 pandemic. Methods: Antibiotic susceptibility testing was conducted on UCO-553 and UCO-554. Both isolates underwent whole-genome sequencing to ascertain their sequence type (ST), core genome multilocus sequence-typing (cgMLST) profile, antibiotic resistance genes, plasmids, and mobile genetic elements. Conjugation experiments were performed for both isolates. Results: Both isolates exhibited broad resistance, including resistance to carbapenems, third-generation cephalosporins, fluoroquinolones, tetracycline, cotrimoxazole, and aminoglycosides. Both isolates belong to sequence type STPAS1761, with a difference of 17 out of 2984 alleles. Each isolate carried a 47,274 bp plasmid with blaNDM-1 and aph(3′)-VI genes and two highly similar plasmids: a 35,184 bp plasmid with tet(Y), sul2, aph(6)-Id, and aph(3″)-Ib genes, and a 6078 bp plasmid containing the ant(2″)-Ia gene. Quinolone-resistance mutations were identified in the gyrA and parC genes of both isolates. Importantly, blaNDM-1 was located within a Tn125 transposon, and tet(Y) was embedded in a Tn5393 transposon. Conjugation experiments successfully transferred blaNDM-1 and tet(Y) into the A. baumannii ATCC 19606 strain, indicating the potential for horizontal gene transfer. Conclusions: This study highlights the critical role of plasmids in disseminating resistance genes in A. bereziniae and underscores the need for the continued genomic surveillance of this emerging pathogen. The findings emphasize the importance of monitoring A. bereziniae for its potential to cause difficult-to-treat infections and its capacity to spread resistance determinants against clinically significant antibiotics. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Community-acquired methicillin-resistant Staphylococcus aureus invasive infections: a case series from Central-South Chile

Author

Aguayo-Reyes, Alejandro, primary, Morales-León, Felipe, additional, Quezada-Aguiluz, Mario, additional, Quezada, Martha, additional, Mella, Sergio, additional, Riedel, Gisela, additional, Herrera-Chávez, Néstor, additional, Espine, Yohana, additional, González-Rocha, Gerardo, additional, and Opazo-Capurro, Andrés, additional

Published
2024
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11. Genomic and Phylogenomic Characterization of Carbapenem-resistant Pseudomonas aeruginosa‘High-risk’ Clone O4/ExoS+/ST654 Circulating in Chilean Hospitals

Author

Opazo-Capurro, Andrés, Aguilar-Vera, Omar Alejandro, González-Muñoz, Paulina, Amsteins-Romero, Luis, Quiroga, Monserrat, Encina, Antonia, Herrera-Chávez, Néstor, Quezada-Aguiluz, Mario, Aguayo-Reyes, Alejandro, Morales-León, Felipe, Illesca, Vijna, Vera, Rodrigo, Salgado, Fabiola, Suazo, Patricio, Fuenzalida, Luz María, Bello-Toledo, Helia, Castillo-Ramírez, Santiago, and González-Rocha, Gerardo

Abstract

•Pseudomonas aeruginosais the main cause of ventilator-associated pneumonia in Chile.•Carbapenem-resistant P. aeruginosais associated to specific ‘high-risk’ clones.•Predominance of the KPC-producing P. aeruginosa‘high-risk’ clone ST654 in Chile.•ST654 ‘high-risk’ lineage is undergoing a particular evolutionary process in Chile.•Most comprehensive genomic analysis of the P. aeruginosa‘high-risk’ clone ST654.

Published
2024
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13. Phenotypic and genotypic antimicrobial resistance in Escherichia coli strains isolated from household dogs in Chile

Author

Galarce, Nicolás, primary, Arriagada, Gabriel, additional, Sánchez, Fernando, additional, Escobar, Beatriz, additional, Miranda, Mauricio, additional, Matus, Sofía, additional, Vilches, Rocío, additional, Varela, Camila, additional, Zelaya, Carlos, additional, Peralta, Josefa, additional, Paredes-Osses, Esteban, additional, González-Rocha, Gerardo, additional, and Lapierre, Lisette, additional

Published
2023
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17. Molecular Characterization of the Convergent Carbapenem-Resistant and Hypervirulent Klebsiella pneumoniae Strain K1-ST23, Collected in Chile during the COVID-19 Pandemic

Author

Morales-León, Felipe, primary, Matus-Köhler, Maximiliano, additional, Araya-Vega, Pablo, additional, Aguilera, Felipe, additional, Torres, Ignacio, additional, Vera, Rodrigo, additional, Ibarra, Camila, additional, Venegas, Sebastián, additional, Bello-Toledo, Helia, additional, González-Rocha, Gerardo, additional, and Opazo-Capurro, Andrés, additional

Published
2023
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19. Isolation of an Extensively Drug-Resistant Pseudomonas aeruginosa exoS + /O4 Strain Belonging to the “High-Risk” Clone ST654 and Coproducer of NDM-1 and the Novel VIM-80

Author

Opazo-Capurro, Andrés, primary, Morales-León, Felipe, additional, Jerez, Christian, additional, Olivares-Pacheco, Jorge, additional, Alcalde-Rico, Manuel, additional, González-Muñoz, Paulina, additional, Bello-Toledo, Helia, additional, Cardenas-Arias, Adriana, additional, Esposito, Fernanda, additional, Lincopán, Nilton, additional, Illesca, Vijna, additional, and González-Rocha, Gerardo, additional

Published
2022
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20. Novel Megaplasmid Driving NDM-1-Mediated Carbapenem Resistance in Klebsiella pneumoniae ST1588 in South America

Author

Quezada-Aguiluz, Mario, primary, Opazo-Capurro, Andrés, additional, Lincopan, Nilton, additional, Esposito, Fernanda, additional, Fuga, Bruna, additional, Mella-Montecino, Sergio, additional, Riedel, Gisela, additional, Lima, Celia A., additional, Bello-Toledo, Helia, additional, Cifuentes, Marcela, additional, Silva-Ojeda, Francisco, additional, Barrera, Boris, additional, Hormazábal, Juan C., additional, and González-Rocha, Gerardo, additional

Published
2022
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21. Phenotypic and Genotypic Characterization of Macrolide, Lincosamide and Streptogramin B Resistance among Clinical Methicillin-Resistant Staphylococcus aureus Isolates in Chile

Author

Quezada-Aguiluz, Mario, primary, Aguayo-Reyes, Alejandro, additional, Carrasco, Cinthia, additional, Mejías, Daniela, additional, Saavedra, Pamela, additional, Mella-Montecinos, Sergio, additional, Opazo-Capurro, Andrés, additional, Bello-Toledo, Helia, additional, Munita, José M., additional, Hormazábal, Juan C., additional, and González-Rocha, Gerardo, additional

Published
2022
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24. Microbiota composition and susceptibility to florfenicol and oxytetracycline of bacterial isolates from mussels (Mytilus spp.) reared on different years and distance from salmon farms

Author

Ramírez, Carolina, primary, Gutiérrez, María Soledad, additional, Venegas, Lucas, additional, Sapag, Catalina, additional, Araya, Carolina, additional, Caruffo, Mario, additional, López, Paulina, additional, Reyes-Jara, Angélica, additional, Toro, Magaly, additional, González-Rocha, Gerardo, additional, Yáñez, José Manuel, additional, and Navarrete, Paola, additional

Published
2022
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28. In vitro antibacterial activity of endodontic bioceramic materials against dual and multispecies aerobic‐anaerobic biofilm models.

Author

Jerez‐Olate, Christian, Araya, Nancy, Alcántara, Raúl, Luengo, Luis, Bello‐Toledo, Helia, González‐Rocha, Gerardo, and Sánchez‐Sanhueza, Gabriela

Subjects
ANTIBACTERIAL agents, CALCIUM silicates, BIOFILMS, LASER microscopy, SCANNING electron microscopy, QUORUM sensing
Abstract

The aim of this in vitro study was to evaluate the antibacterial activity of calcium silicate repair cements and sealers against a dual‐species planktonic aerobic model with different aging times and the ability to inhibit the formation of a mature 21‐day‐old multispecies anaerobic biofilm. The antibacterial activity of ProRoot MTA, MTA Angelus, Biodentine, BioRoot RCS and TotalFill BC sealer against a dual‐species aerobic planktonic model, as well as measuring how materials were affected by aging, was evaluated using the Modified Direct Contact Test. Subsequently, the ability to inhibit the formation of a mature multispecies anaerobic biofilm was evaluated using scanning electron microscopy complemented with confocal laser scanning microscopy. Biodentine and BioRoot RCS had higher antibacterial action, and Biodentine was able to maintain its antibacterial action after a prolonged aging period in vitro. Calcium silicate repair cement MTA ProRoot and Biodentine had higher antibiofilm action. [ABSTRACT FROM AUTHOR]

Published
2022
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32. Isolation of Ciprofloxacin and Ceftazidime-Resistant Enterobacterales From Vegetables and River Water Is Strongly Associated With the Season and the Sample Type

Author

Díaz-Gavidia, Constanza, primary, Barría, Carla, additional, Rivas, Lina, additional, García, Patricia, additional, Alvarez, Francisca P., additional, González-Rocha, Gerardo, additional, Opazo-Capurro, Andrés, additional, Araos, Rafael, additional, Munita, José M., additional, Cortes, Sandra, additional, Olivares-Pacheco, Jorge, additional, Adell, Aiko D., additional, and Moreno-Switt, Andrea I., additional

Published
2021
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35. Antibiotic Resistance of Enterococcus faecalis from Persistent Endodontic Infections

Author

Seguel, Natalia, Quezada-Aguiluz, Mario, González-Rocha, Gerardo, Bello-Toledo, Helia, and Sánchez-Sanhueza, Gabriela

Subjects
antibiotic resistance, antibiotic resistance genes, E. faecalis, persistent endodontic lesions, lesiones endodóncicas persistentes, genes de resistencia a antibióticos, resistencia a antibióticos
Abstract

Enterococci are important nosocomial pathogens due to their intrinsic multiresistance and the acquisition of new antibiotic resistance genes (ARG). Enterococcus faecalis has been shown to be one of the main pathogens in persistent endodontic infections, therefore, the main objective of this study was to evaluate the phenotype and resistance genotype of strains of E. faecalis isolated from teeth with persistent endodontic lesions, to the most commonly prescribed antibiotics in dentistry. Thirteen strains of E. faecalis of different pulsotype were analyzed to evaluate the susceptibility to antibiotics, amoxicillin, amoxicillin/clavulanic acid, tetracycline, erythromycin and metronidazole, using the Epsilometer test (E- test) and the presence of beta-lactamases with nitrocefin test. Finally, the detection of ARG was performed with a molecular polymerase chain reaction (PCR) technique and confirmed by the sequencing of the amplification products. Fisher's exact test was used, using 95 % confidence. Regarding the phenotype of resistance, the evaluated strains, independent of the pulsotype, were totally resistant to the action of metronidazole. Antibiotics with higher minimum inhibitory concentration (MIC) after metronidazole include tetracycline and erythromycin. In contrast, lower MIC are applied to the combination of amoxicillin with clavulanic acid. The nitrocefin test was positive only in one strain. Genotypically, two genetically distant strains isolated from a single patient, presented a genotype of resistance to erythromycin, determined by the presence of the ermB gene. No statistically significant relationship was found between phenotypic resistance and the presence of ARG in relation to erythromycin (p> 0.05). It was concluded that isolates of E. faecalis from persistent endodontic infections showed phenotypes of resistance to several antimicrobial agents, all of which were susceptible to amoxicillin/clavulanic acid. Periodic evaluation of susceptibility to antibiotics is suggested as an important practice for the surveillance of antibiotic resistance in oral strains. RESUMEN: Los enterococos son importantes patógenos nosocomiales debido a su multi resistencia intrínseca y la adquisición de nuevos genes de resistencia a los antibióticos (ARG). Enterococcus faecalis es uno de los principales patógenos en infecciones endodónticas persistentes, por lo tanto, el objetivo principal de este estudio fue evaluar el fenotipo y el genotipo de resistencia de cepas de E. faecalis aisladas de dientes con lesiones endodóncicas persistentes, a los antibióticos comúnmente recetados en odontología. Se analizaron 13 cepas de E. faecalis de diferentes pulsotipos para evaluar la susceptibilidad a los antibióticos, amoxicilina, amoxicilina / ácido clavulánico, tetraciclina, eritromicina y metronidazol, utilizando la prueba de Epsilometría (E-test) y la presencia de beta-lactamasas con prueba de nitrocefina. Finalmente, la detección de ARG se realizó con una técnica molecular de reacción en cadena de la polimerasa (PCR) y se confirmó mediante la secuenciación de los productos de amplificación. Se utilizó la prueba exacta de Fisher, con un 95 % de confianza. En cuanto al fenotipo de resistencia, las cepas evaluadas, independientes del pulsotipo, fueron totalmente resistentes a la acción del metronidazol. Los antibióticos con los valores más altos de concentración mínima inibitoria (CMI) después del metronidazol incluyen tetraciclina y eritromicina. En contraste, las CMI mas bajas se aplican a la combinación de amoxicilina con ácido clavulánico. La prueba de nitrocefina fue positiva solo en una cepa. Genotípicamente, dos cepas distantes genéticamente, aisladas de un mismo paciente fueron positivas para el gen ermB. No se encontró una relación estadísticamente significativa entre la resistencia fenotípica y la presencia de ARG en relación con la eritromicina (p> 0,05). Se concluyó que los aislamientos de E. faecalis de infecciones endodónticas persistentes mostraron fenotipos de resistencia a varios agentes antimicrobianos, todos los cuales fueron susceptibles a amoxicilina / ácido clavulánico. Se sugiere una evaluación periódica de la susceptibilidad a los antibióticos como una práctica importante para la vigilancia de la resistencia a los antibióticos en las cepas orales.

Published
2020

36. Subcutaneous abscess caused by Trueperella pyogenes in a Southern pudu (Pudu puda)

Author

Llanos-Soto, Sebastián, González-Muñoz, Paulina, Opazo-Capurro, Alexis, González-Rocha, Gerardo, and González-Acuña, Daniel

Subjects
abscess, deer, Truepurella pyogenes, pudu
Abstract

A case of an abscess on the head of a captive Southern pudu (Pudu puda) caused by Trueperella pyogenes is described. A diagnosis was done based on bacterial culture and MALDI-TOF MS identification. Traumatic inoculation of the bacterium in the subcutaneous tissue is speculated.

Published
2020

38. Selective digestive decontamination with oral colistin plus gentamicin for persistent bacteraemia caused by non-carbapenemase-producing carbapenem-resistant Klebsiella pneumoniae in a neutropenic patient

Author

Spencer-Sandino, Maria, primary, Riquelme-Neira, Roberto, additional, Shropshire, William C, additional, Dinh, An Q, additional, González-Rocha, Gerardo, additional, González-Muñoz, Paulina, additional, Vera-Leiva, Alejandra, additional, Araos, Rafael, additional, Hanson, Blake, additional, Arias, Cesar A, additional, and Munita, José M, additional

Published
2021
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39. Phenotypic and Genotypic Characterization of Macrolide, Lincosamide and Streptogramin B Resistance among Clinical Methicillin-Resistant S taphylococcus aureus Isolates in Chile.

Author

Quezada-Aguiluz, Mario, Aguayo-Reyes, Alejandro, Carrasco, Cinthia, Mejías, Daniela, Saavedra, Pamela, Mella-Montecinos, Sergio, Opazo-Capurro, Andrés, Bello-Toledo, Helia, Munita, José M., Hormazábal, Juan C., and González-Rocha, Gerardo

Subjects
MICROCOCCACEAE, GENOTYPES, METHICILLIN-resistant staphylococcus aureus, PHENOTYPES, DAPTOMYCIN, AZITHROMYCIN
Abstract

Macrolides, lincosamides, and type B streptogramins (MLSB) are important therapeutic options to treat methicillin-resistant Staphylococcus aureus (MRSA) infections; however, resistance to these antibiotics has been emerging. In Chile, data on the MLSB resistance phenotypes are scarce in both community-(CA) and hospital-acquired (HA) MRSA isolates. Antimicrobial susceptibility to MLSB was determined for sixty-eight non-repetitive isolates of each HA-(32) and CA-MRSA (36). Detection of SCCmec elements, ermA, ermB, ermC, and msrA genes was performed by PCR. The predominant clones were SCCmec I-ST5 (HA-MRSA) and type IVc-ST8 (CA-MRSA). Most of the HA-MRSA isolates (97%) showed resistance to clindamycin, erythromycin, azithromycin, and clarithromycin. Among CA-MRSA isolates, 28% were resistant to erythromycin, azithromycin, and 25% to clarithromycin. All isolates were susceptible to linezolid, vancomycin, daptomycin and trimethoprim/sulfamethoxazole, and over 97% to rifampicin. The ermA gene was amplified in 88% of HA-MRSA and 17% of CA-MRSA isolates (p < 0.001). The ermC gene was detected in 6% of HA-SARM and none of CA-SARM isolates, whereas the msrA gene was only amplified in 22% of CA-MRSA (p < 0.005). Our results demonstrate the prevalence of the cMLSB resistance phenotype in all HA-MRSA isolates in Chile, with the ermA being the predominant gene identified among these isolates. [ABSTRACT FROM AUTHOR]

Published
2022
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40. Carbapenemasas en aislamientos de Pseudomonas aeruginosa resistentes a carbapenémicos aisladas en hospitales de Chile

Author

Costa, Jandira S. Tomás da, primary, Lima, Celia A., additional, Vera-Leiva, Alejandra, additional, San Martin Magdalena, Iván, additional, Bello-Toledo, Helia, additional, Domínguez Yévenes, Mariana, additional, Opazo-Capurro, Andrés, additional, Mella Montecinos, Sergio, additional, Quezada-Aguiluz, Mario, additional, and González-Rocha, Gerardo, additional

Published
2021
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45. Hypervirulent and hypermucoviscous extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Klebsiella variicola in Chile

Author

Morales-León, F., primary, Opazo-Capurro, A., additional, Caro, C., additional, Lincopan, N., additional, Cardenas-Arias, A., additional, Esposito, F., additional, Illesca, V., additional, Rioseco, M. L., additional, Domínguez-Yévenes, M., additional, Lima, C. A., additional, Bello-Toledo, H., additional, and González-Rocha, Gerardo, additional

Published
2020
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46. Statistical Optimisation of Phenol Degradation and Pathway Identification through Whole Genome Sequencing of the Cold-Adapted Antarctic Bacterium, Rhodococcus sp. Strain AQ5-07

Author

Lee, Gillian Li Yin, primary, Zakaria, Nur Nadhirah, additional, Convey, Peter, additional, Futamata, Hiroyuki, additional, Zulkharnain, Azham, additional, Suzuki, Kenshi, additional, Abdul Khalil, Khalilah, additional, Shaharuddin, Noor Azmi, additional, Alias, Siti Aisyah, additional, González-Rocha, Gerardo, additional, and Ahmad, Siti Aqlima, additional

Published
2020
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49. Biosurfactant Production and Growth Kinetics Studies of the Waste Canola Oil-Degrading Bacterium Rhodococcus erythropolis AQ5-07 from Antarctica

Author

Ibrahim, Salihu, primary, Abdul Khalil, Khalilah, additional, Zahri, Khadijah Nabilah Mohd, additional, Gomez-Fuentes, Claudio, additional, Convey, Peter, additional, Zulkharnain, Azham, additional, Sabri, Suriana, additional, Alias, Siti Aisyah, additional, González-Rocha, Gerardo, additional, and Ahmad, Siti Aqlima, additional

Published
2020
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