Browsing by Author "Riquelme-Neira, Roberto"

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    Antibiotic Consumption During the Coronavirus Disease 2019 Pandemic and Emergence of Carbapenemase-Producing Klebsiella pneumoniae Lineages Among Inpatients in a Chilean Hospital: A Time-Series Study and Phylogenomic Analysis
    (2023) Allel, Kasim; Peters, Anne; Conejeros, Jose; Martinez, Jose R. W.; Spencer-Sandino, Maria; Riquelme-Neira, Roberto; Rivas, Lina; Rojas, Pamela; Orellana Chea, Cristian; Garcia, Patricia; Araos, Rafael; McGovern, Olivia; Patel, Twisha S.; Arias, Cesar A.; Lessa, Fernanda C.; Undurraga, Eduardo A.; Munita, Jose M.
    The increased usage of carbapenems and broad-spectrum & beta;-lactams during the COVID-19 pandemic was associated with a higher prevalence of carbapenemase-producing Klebsiella pneumoniae in a public hospital in Chile. We observed emergence and spread of bla(NDM) ST45 during the pandemic.
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    Dynamics of the MRSA Population in a Chilean Hospital: a Phylogenomic Analysis (2000-2016)
    (2023) Martinez, Jose R. W.; Planet, Paul J.; Spencer-Sandino, Maria; Rivas, Lina; Diaz, Lorena; Moustafa, Ahmed M.; Quesille-Villalobos, Ana; Riquelme-Neira, Roberto; Alcalde-Rico, Manuel; Hanson, Blake; Carvajal, Lina P.; Rincon, Sandra; Reyes, Jinnethe; Lam, Marusella; Calderon, Juan F.; Araos, Rafael; Garcia, Patricia; Arias, Cesar A.; Munita, Jose M.
    Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health pathogen that disseminates through the emergence of successful dominant clones in specific geographic regions. Knowledge of the dissemination and molecular epidemiology of MRSA in Latin America is scarce and is largely based on small studies or more limited typing techniques that lack the resolution to represent an accurate description of the genomic landscape.
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    Geographic divergence of methicillin-resistant Staphylococcus aureus ST5-SCCmecI in the aftermath of a major earthquake and tsunami: impact of a plasmid harboring heavy metal resistance genes
    (2025) Martínez, José R. W.; Alcalde-Rico, Manuel; Jara-Videla, Estefanía; Reyes, Jinnethe; Carvajal, Lina P.; Sandra Rincon; Ríos, Rafael; Diaz, Lorena; Quesille-Villalobos, Ana; Riquelme-Neira, Roberto; Rivas, Lina; Moustafa, Ahmed M.; Blake, Hanson; Undurraga, Eduardo A.; Olivares-Pacheco, Jorge; García Cañete, Patricia; Araos, Rafael; Planet, Paul J.; Arias, César A.; Munita, José M.
    Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health menace. The global spread of MRSA is characterized by successive waves of epidemic clones dominating specific geographical regions. The acquisition of genes encoding resistance to heavy metals (HMRGs) is thought to be a key feature in the geographic divergence of MRSA. However, the cause-effect relationship between the presence of HMRGs and the divergence of MRSA clones remains to be clarified. In this study, we assessed the role that HMRGs may have played in the evolutionary divergence of the MRSA ST5-SCCmecI lineage in Latin America. We conducted a genomic characterization of 113 MRSA clinical isolates from six Latin American healthcare centers, including 53 isolates collected from two cities in Chile (Santiago and Concepción). We found a plasmid (pSCL4752) harboring arsenic, cadmium, and mercury resistance genes in 65% (n = 71) of the ST5-SCCmecI isolates. We also observed a geographic divergence associated with the presence of pSCL4752 in Chilean isolates, with a higher frequency in isolates from Concepción (88%) compared to Santiago (29%). Interestingly, a molecular clock analysis revealed that this divergence occurred in the aftermath of an 8.8 Mw earthquake and tsunami that struck the Concepción area in 2010. Moreover, our results demonstrate that the carriage of pSCL4752 can be beneficial or detrimental for ST5-SCCmecI isolates, depending on the environmental availability of these heavy metals. Our results suggest that the divergence of the ST5-SCCmecI MRSA lineage in Latin America could have been fostered by environmental disasters and influenced by the presence/absence of HMRGs harbored in a plasmi.
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    Heavy Metal Pollution From a Major Earthquake and Tsunami in Chile Is Associated With Geographic Divergence of Clinical Isolates of Methicillin-Resistant Staphylococcus aureus in Latin America
    Martínez, José R.W.; Alcalde-Rico, Manuel; Jara-Videla, Estefanía; Ríos, Rafael; Moustafa, Ahmed M.; Blake, Hanson; Rivas, Lina; Carvajal, Lina P.; Rincon, Sandra; Díaz, Lorena; Jinnethe Reyes, Jinnethe; Quesille-Villalobos, Ana; Riquelme-Neira, Roberto; Undurraga, Eduardo A.; Olivares-Pacheco, Jorge; García Cañeta, Patricia del Carmen; Araos, Rafael; Planet, Paul J.; Arias, César A.; Munita, José M.
    Methicillin-resistant Staphylococcus aureus (MRSA) is a priority pathogen listed by the World Health Organization. The global spread of MRSA is characterized by successive waves of epidemic clones that predominate in specific geographical regions. The acquisition of genes encoding resistance to heavy-metals is thought to be a key feature in the divergence and geographical spread of MRSA. Increasing evidence suggests that extreme natural events, such as earthquakes and tsunamis, could release heavy-metals into the environment. However, the impact of environmental exposition to heavy-metals on the divergence and spread of MRSA clones has been insufficiently explored. We assess the association between a major earthquake and tsunami in an industrialized port in southern Chile and MRSA clone divergence in Latin America. We performed a phylogenomic reconstruction of 113 MRSA clinical isolates from seven Latin American healthcare centers, including 25 isolates collected in a geographic area affected by an earthquake and tsunami that led to high levels of heavy-metal environmental contamination. We found a divergence event strongly associated with the presence of a plasmid harboring heavy-metal resistance genes in the isolates obtained in the area where the earthquake and tsunami occurred. Moreover, clinical isolates carrying this plasmid showed increased tolerance to mercury, arsenic, and cadmium. We also observed a physiological burden in the plasmid-carrying isolates in absence of heavy-metals. Our results are the first evidence that suggests that heavy-metal contamination, in the aftermath of an environmental disaster, appears to be a key evolutionary event for the spread and dissemination of MRSA in Latin America.
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    Role of the multi-drug efflux systems on the baseline susceptibility to ceftazidime/avibactam and ceftolozane/tazobactam in clinical isolates of non-carbapenemase-producing carbapenem-resistant Pseudomonas aeruginosa
    (2022) Jose Contreras-Gomez, Maria; Martinez, Jose R. W.; Rivas, Lina; Riquelme-Neira, Roberto; Ugalde, Juan A.; Wozniak, Aniela; Garcia, Patricia; Munita, Jose M.; Olivares-Pacheco, Jorge; Alcalde-Rico, Manuel
    Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is one of the pathogens that urgently needs new drugs and new alternatives for its control. The primary strategy to combat this bacterium is combining treatments of beta-lactam with a beta-lactamase inhibitor. The most used combinations against P. aeruginosa are ceftazidime/avibactam (CZA) and ceftolozane/tazobactam (C/T). Although mechanisms leading to CZA and C/T resistance have already been described, among which are the resistance-nodulation-division (RND) efflux pumps, the role that these extrusion systems may play in CZA, and C/T baseline susceptibility of clinical isolates remains unknown. For this purpose, 161 isolates of non-carbapenemase-producing (Non-CP) CRPA were selected, and susceptibility tests to CZA and C/T were performed in the presence and absence of the RND efflux pumps inhibitor, Phenylalanine-arginine beta-naphthylamide (PA beta N). In the absence of PA beta N, C/T showed markedly higher activity against Non-CP-CRPA isolates than observed for CZA. These results were even more evident in isolates classified as extremely-drug resistant (XDR) or with difficult-to-treat resistance (DTR), where CZA decreased its activity up to 55.2% and 20.0%, respectively, whereas C/T did it up to 82.8% (XDR), and 73.3% (DTR). The presence of PA beta N showed an increase in both CZA (37.6%) and C/T (44.6%) activity, and 25.5% of Non-CP-CRPA isolates increased their susceptibility to these two combined antibiotics. However, statistical analysis showed that only the C/T susceptibility of Non-CP-CRPA isolates was significantly increased. Although the contribution of RND activity to CZA and C/T baseline susceptibility was generally low (two-fold decrease of minimal inhibitory concentrations [MIC]), a more evident contribution was observed in a non-minor proportion of the Non-CP-CRPA isolates affected by PA beta N [CZA: 25.4% (15/59); C/T: 30% (21/70)]. These isolates presented significantly higher MIC values for C/T. Therefore, we conclude that RND efflux pumps are participating in the phenomenon of baseline susceptibility to CZA and, even more, to C/T. However, the genomic diversity of clinical isolates is so great that deeper analyzes are necessary to determine which elements are directly involved in this phenomenon.
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    Widespread Environmental Presence of Multidrug-Resistant Salmonella in an Equine Veterinary Hospital That Received Local and International Horses
    (2020) Soza-Ossandon, Paula; Rivera, Dacil; Tardone, Rodolfo; Riquelme-Neira, Roberto; Garcia, Patricia; Hamilton-West, Christopher; Adell, Aiko D.; Gonzalez-Rocha, Gerardo; Moreno-Switt, Andrea, I
    Salmonella entericais a highly infectious microorganism responsible for many outbreaks reported in equine hospitals. Outbreaks are characterized by high morbidity and mortality rates, nosocomial transmission to other patients, zoonotic transmission to hospital personnel, and even closure of facilities. In this study, 545 samples (environmental and hospitalized patients) were collected monthly during a 1-year period from human and animal contact surfaces in an equine hospital that received local and international horses. A total of 22Salmonellaisolates were obtained from human contact surfaces (e.g., offices and pharmacy) and animal contact surfaces (e.g., stalls, surgery room, and waterers), and one isolate from a horse. Molecular serotyping revealed 18 isolates asSalmonellaTyphimurium and three asSalmonellaInfantis. Nineteen isolates were resistant to at least one antimicrobial class, and only two isolates were susceptible to all antimicrobials tested. In addition, we identified nine multidrug-resistant (MDR) isolates inS. Typhimurium, which displayed resistance to up to eight antimicrobials (i.e., amoxicillin/clavulanate, ampicillin, ciprofloxacin, chloramphenicol, streptomycin, gentamicin, trimethoprim/sulfamethoxazole, and tetracycline). Pulsed-field gel electrophoresis (PFGE) revealed the presence of three PFGE patterns permanently present in the environment of the hospital during our study. The persistent environmental presence of MDRSalmonellaisolates, along with the fact that local and international horses are attended in this hospital, highlights the importance of improving biosecurity programs to prevent disease in horses and the hospital personnel and also for the global dissemination and acquisition of MDRSalmonella.