INEI http://sgc.anlis.gob.ar/handle/123456789/4 2026-05-13T19:47:36Z 2026-05-13T19:47:36Z Bustos, C P Gallardo.Mauro Julian Moroni, Miriam Ivanissevich, A Viñas, María R. Mesplet, María Chacana, Pablo http://sgc.anlis.gob.ar/handle/123456789/2743 2026-05-07T18:36:02Z 2026-04-01T00:00:00Z

Title: Equine Salmonella in Argentina: Genetic relatedness with humans and other animal species and first detection of serovar Freetown Authors: Bustos, C P; Gallardo.Mauro Julian; Moroni, Miriam; Ivanissevich, A; Viñas, María R.; Mesplet, María; Chacana, Pablo Abstract: Salmonellosis in horses can cause severe enteritis with diarrhea, fever, and colic, which is usually severe in foals and hospitalized or immunocompromised animals. Carrier horses may intermittently shed Salmonella, thereby acting as a source of infection for other animals and humans. The aim of this study was to investigate the occurrence and molecular subtyping of Salmonella spp. in horses from Argentina, focusing on potential zoonotic relevance. Only a single isolate (S. Newport) was obtained from fecal samples of 249 clinically healthy horses (2018-2022), indicating a very low carrier detection rate (0.4%). Additionally, 13 isolates from horses with clinical signs of salmonellosis (2006-2017) were analyzed, which comprised S. Typhimurium (n = 9), S. Newport (n = 2), S. Oranienburg (n = 1), and S. Freetown (n = 1). Pulsed-field gel electrophoresis (PFGE) revealed genetic diversity among Salmonella serovars, including clonal outbreaks of S. Typhimurium in a hospital. Comparative analyses using the National PulseNet database demonstrated that many equine isolates shared indistinguishable PFGE patterns with strains from human, bovine, porcine, caprine, and avian origin. Our results suggest the circulation of common Salmonella clones among several unrelated species and highlight that horses may act as potential reservoirs within a One Health framework. The identification of S. Freetown in equines, representing the first report in South America, further emphasizes the need to enhance the surveillance of the pathogen. Despite limitations due to sample size and underdiagnosis in veterinary settings, these findings support the inclusion of equine populations in epidemiological monitoring to improve the management of zoonotic risks associated with Salmonella.

2026-04-01T00:00:00Z Madariaga, María Julia Caraballo, Diego A Teijeiro, Maria Luisa Boeri, Eduardo Cadario, María Estela http://sgc.anlis.gob.ar/handle/123456789/2741 2026-05-07T18:35:33Z 2024-11-14T00:00:00Z

Title: Molecular Detection and Genotyping of Chlamydia psittaci in Birds in Buenos Aires City, Argentina Authors: Madariaga, María Julia; Caraballo, Diego A; Teijeiro, Maria Luisa; Boeri, Eduardo; Cadario, María Estela Abstract: Chlamydia psittaci is a bacterium that infects several species of birds and mammals. It is the causal agent of avian chlamydiosis and psittacosis in humans and it is globally distributed. Chlamydia psittaci is one of the main zoonotic pathogens transmitted by birds. In Argentina, there has been limited research on the prevalence and genetic variability of C. psittaci. The aim of this study was to detect and genotype C. psittaci using molecular techniques in birds living in Buenos Aires City, Argentina, during the period 2012–2015. A descriptive, observational, retrospective and cross-sectional study was carried out. A total of 983 bird samples submitted for diagnosis of avian chlamydiosis were analyzed. The frequency of C. psittaci was 12.54% and 7.89% in Psittaciformes and Columbiformes, respectively. A 348 bp region of the ompA gene was sequenced in positive samples. Molecular genotyping was performed through a Bayesian phylogenetic analysis. Of the 983 bird samples, 83 were positive for C. psittaci and 44 could be sequenced. The genotypes found were A, B, and E. Despite the high levels of host specificity, we found six psittacids with genotype B and one pigeon with genotype A, reflecting the affiliative interaction between Psittaciformes and Columbiformes. This study represents the first survey reporting the presence of C. psittaci in birds within the largest and most populous city in Argentina.

2024-11-14T00:00:00Z Mahadevan, Ramya Garcia, Estefany Sharma, Rajnikant Qiu, Hongqiang Elsheikh, Ahmed Parambi, Robert Saad Abboud, Cely Pasteran, Fernando Ramirez, Maria Soledad Kaye, Keith S Bonomo, Robert A Rao, Gauri G. http://sgc.anlis.gob.ar/handle/123456789/2737 2026-04-22T14:48:41Z 2025-12-19T00:00:00Z

Title: A mechanism-based pharmacokinetic/pharmacodynamic analysis of polymyxin B-based combination therapy against carbapenem-resistant Klebsiella pneumoniae isolates with diverse phenotypic and genotypic resistance mechanisms Authors: Mahadevan, Ramya; Garcia, Estefany; Sharma, Rajnikant; Qiu, Hongqiang; Elsheikh, Ahmed; Parambi, Robert; Saad Abboud, Cely; Pasteran, Fernando; Ramirez, Maria Soledad; Kaye, Keith S; Bonomo, Robert A; Rao, Gauri G. Abstract: Increased resistance to β-lactams/β-lactamase inhibitors by mutations in β-lactamase genes, porins, and efflux pumps complicates the management of carbapenem-resistant Klebsiella pneumoniae (CRKP). Polymyxin B (PMB)-based combination therapy is the best alternative treatment for middle and low-income countries that cannot access the latest medicines. It is crucial to know both phenotypic and genotypic characteristics of a pathogen to understand the killing effect of each drug and its combinations. Hence, our objective was to incorporate mechanistic insights gained from resistance mechanisms of each isolate to develop a mechanism-based pharmacokinetic/pharmacodynamic model. Six clinical CRKP isolates with diverse genotypic resistance expressing blaKPC, blaNDM, porin, and mgrB mutations were used for static concentration time kill (SCTK) assays to evaluate the rate and extent of killing by monotherapy, double and triple combinations using PMB (0.5-64 mg/L), meropenem (10-120 mg/L), and fosfomycin (75-500 mg/L). Isolate BRKP28 expressed non-functional MgrB (a regulatory protein) and high-level phenotypic resistance (PMB MIC: >128 mg/L). In line with the observed resistance, the model estimated that BRKP28 had a reduced maximum killing rate constant for PMB (3.61 h⁻¹) relative to other isolates. The mechanistic synergy of PMB, due to outer membrane disruption, was incorporated into three isolates with porin mutations. PMB demonstrated 83%-88% mechanistic synergy with meropenem and 81%-98% with fosfomycin. The model further estimated that a very low concentration of PMB (0.49-0.64 mg/L) was sufficient to achieve 50% of the maximum synergy. Simulations using population pharmacokinetic models showed that combination therapy of PMB (1 mg/kg q12h) and fosfomycin (8 g q8h) achieved >73% reduction in area under the bacterial load-versus-time curve across four isolates. The triple combination therapy achieved a 67.7% reduction in non-carbapenamase producing isolate. These findings demonstrates that a low PMB dosing regimen (1 mg/kg q12h) can produce synergistic effects in combination therapy and may be effective in managing infections caused by CRKP, including PMB resistant isolates. Description: Fil: Mahadevan, Ramya. Titus Family Department of Clinical Practice, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, California, USA. Fil: García, Estefany. Division of Pharmaceutics and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. Fil: Sharma, Rajnikant. Titus Family Department of Clinical Practice, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, California, USA. Fil: Qiu, Hongqiang. Division of Pharmaceutics and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Pharmacy, Fujian Medical University Union Hospital, Fuzhou, People's Republic of China; College of Pharmacy, Fujian Medical University, Fuzhou, People's Republic of China. Fil: Elsheikh, Ahmed. Division of Pharmaceutics and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. Fil: Parambi, Robert. Division of Pharmaceutics and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. Fil: Saad Abboud, Cely. Instituto Dante Pazzanese de Cardiologia, São Paulo, Brazil. Fil: Pasteran, Fernando. Antimicrobianos, Instituto Nacional de Enfermedades Infecciosas, Antimicrobial Service of the National Institute of Infectious Diseases (ANLIS Dr. Carlos G. Malbrán), Buenos Aires, Argentina. Fil: Ramirez, María Soledad. Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, California, USA. Fil: Kaye, Keith S. Division of Allergy, Immunology and Infectious Diseases, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA. Fil: Bonomo, Robert A. Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA; CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, Ohio, USA; Geriatric Research Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Education and Clinical Center, Cleveland, Ohio, USA; Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA; Departments of Pharmacology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA. Fil: Rao, Gauri G. Titus Family Department of Clinical Practice, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, California, USA; Division of Pharmaceutics and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

2025-12-19T00:00:00Z Balbuena, Juan Pablo Córdova, Ezequiel Mykietiuk, Analia Farina, Javier Gañete, Marcelo Scapellato, Pablo G. Lespada, María Inés Nannini, Esteban Contreras, Rosa Cunto, Eleonora Barcelona, Laura Pasteran, Fernando Salgueira, Claudia Hojman, Martin Blanco, Miriam Cox Fernandez, William E Lopez Alegre, Horacio Ezcurra, Cecilia Godoy, Dario Biglia, Maria A Lopez Furst, Maria J Mendez, Gustavo Aguirre Rios, Maria F Messina, Oscar Ciappina, Antonella Pálizas, Fernando Altclas, Javier Gaudenzi, Giuliano Cardone, Romina Sánchez-Cunto, Milagro Ruiz, Mariquena Perez,Gabriel Sanchez, Cesar Stryjewski,Martin E http://sgc.anlis.gob.ar/handle/123456789/2736 2026-04-16T16:52:04Z 2025-12-24T00:00:00Z

Title: Carbapenem-Resistant Gram-Negative Bacilli Bacteremia in Argentina (EMBARCAR): Findings From a Prospective, Multicenter Cohort Study Authors: Balbuena, Juan Pablo; Córdova, Ezequiel; Mykietiuk, Analia; Farina, Javier; Gañete, Marcelo; Scapellato, Pablo G.; Lespada, María Inés; Nannini, Esteban; Contreras, Rosa; Cunto, Eleonora; Barcelona, Laura; Pasteran, Fernando; Salgueira, Claudia; Hojman, Martin; Blanco, Miriam; Cox Fernandez, William E; Lopez Alegre, Horacio; Ezcurra, Cecilia; Godoy, Dario; Biglia, Maria A; Lopez Furst, Maria J; Mendez, Gustavo; Aguirre Rios, Maria F; Messina, Oscar; Ciappina, Antonella; Pálizas, Fernando; Altclas, Javier; Gaudenzi, Giuliano; Cardone, Romina; Sánchez-Cunto, Milagro; Ruiz, Mariquena; Perez,Gabriel; Sanchez, Cesar; Stryjewski,Martin E Abstract: Background: Bloodstream infections (BSIs) caused by carbapenem-resistant gram-negative bacilli (CR-GNB) are difficult-to-treat infections associated with high mortality. Outcomes of BSI due to CR-GNB may vary in different countries. Methods: Prospective observational, multicenter study, including consecutive hospitalized index patients aged ≥18 years, with a positive blood culture for CR-GNB, between July 2020 and March 2022 in Argentina. Among patients with Klebsiella pneumoniae BSIs, logistic regressions adjusted by propensity score (PS) were used to identify variables associated with 30-day mortality. Results: Overall, 466 patients with CR-GNB BSIs were included. The mean age was 56.7 (SD ±16) years and most patients (75%) were in critical care units. The median INCREMENT-CPE mortality score was 10 (IQR, 6-12). Most common micro-organisms were K pneumoniae (53%) and Acinetobacter baumannii (25%). Among Enterobacterales, resistance mechanisms included K pneumoniae carbapenemase (KPC) in 50%, metallo-beta-lactamase carbapenemase (MBL) in 48%, OXA carbapenemase in 6%, and a combination of carbapenemases in 5% of patients. Overall, 30-day mortality was 52%. Among patients with BSI due to K pneumoniae, the PS-adjusted multivariate analysis showed that an INCREMENT-CPE score ≥8 points (odds ratio [OR], 3.48; 95% CI, 1.53, 7.93) was associated with increased 30-day mortality. In contrast, the use of regimens including ceftazidime-avibactam alone or in combination with aztreonam was associated with decreased 30-day mortality (OR, .20; 95% CI, .09, .47). Conclusions: BSIs due to CR-GNB are associated with high mortality rates in Argentina. Among patients with CR-K pneumoniae bacteremia the use of ceftazidime-avibactam alone or in combination with aztreonam was associated with a reduction in mortality.

2025-12-24T00:00:00Z