Examinando por Autor "Benavides, Julio"
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Ítem Fecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae in hospital and community settings in Chad(BioMed Central Ltd., 2019-11) Ouchar Mahamat, Oumar; Tidjani, Abdelsalam; Lounnas, Manon; Hide, Mallorie; Benavides, Julio; Somasse, Calèbe; Ouedraogo, Abdoul-Salam; Sanou, Soufiane; Carrière, Christian; Bañuls, Anne-Laure; Jean-Pierre, Hélène; Dumont, Yann; Godreuil, SylvainBackground: Fecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) remains poorly documented in Africa. The objective of this study was to determine the prevalence of ESBL-PE fecal carriage in Chad. Methods: In total, 200 fresh stool samples were collected from 100 healthy community volunteers and 100 hospitalized patients from January to March 2017. After screening using ESBL-selective agar plates and species identification by MALDI-TOF mass spectrometry, antibiotic susceptibility was tested using the disk diffusion method, and ESBL production confirmed with the double-disc synergy test. The different ESBL genes in potential ESBL-producing isolates were detected by PCR and double stranded DNA sequencing. Escherichia coli phylogenetic groups were determined using a PCR-based method. Results: ESBL-PE fecal carriage prevalence was 44.5% (51% among hospitalized patients vs 38% among healthy volunteers; p < 0.05). ESBL-producing isolates were mostly Escherichia coli (64/89) and Klebsiella pneumoniae (16/89). PCR and sequencing showed that 98.8% (87/89) of ESBL-PE harbored bla CTX-M genes: bla CTX-M-15 in 94.25% (82/87) and bla CTX-M-14 in 5.75% (5/87). Phylogroup determination by quadruplex PCR indicated that ESBL-producing E. coli isolates belonged to group A (n = 17; 27%), C (n = 17; 27%), B2 (n = 9; 14%), B1 (n = 8; 13%), D (n = 8; 13%), E (n = 1; 1.6%), and F (n = 1; 1.6%). The ST131 clone was identified in 100% (9/9) of E. coli B2 strains. Conclusions: The high fecal carriage rate of ESBL-PE associated with CTX-M-15 in hospital and community settings of Chad highlights the risk for resistance transmission between non-pathogenic and pathogenic bacteria. © 2019 The Author(s).Ítem Fecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae in hospital and community settings in Chad(BioMed Central Ltd., 2019-10-31) Ouchar Mahamat, Oumar; Tidjani, Abdelsalam; Lounnas, Manon; Hide, Mallorie; Benavides, Julio; Somasse, Calèbe; Ouedraogo, Abdoul-Salam; Sanou, Soufiane; Carrière, Christian; Bañuls, Anne-Laure; Jean-Pierre, Hélène; Dumont, YannBackground: Fecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) remains poorly documented in Africa. The objective of this study was to determine the prevalence of ESBL-PE fecal carriage in Chad. Methods: In total, 200 fresh stool samples were collected from 100 healthy community volunteers and 100 hospitalized patients from January to March 2017. After screening using ESBL-selective agar plates and species identification by MALDI-TOF mass spectrometry, antibiotic susceptibility was tested using the disk diffusion method, and ESBL production confirmed with the double-disc synergy test. The different ESBL genes in potential ESBL-producing isolates were detected by PCR and double stranded DNA sequencing. Escherichia coli phylogenetic groups were determined using a PCR-based method. Results: ESBL-PE fecal carriage prevalence was 44.5% (51% among hospitalized patients vs 38% among healthy volunteers; p < 0.05). ESBL-producing isolates were mostly Escherichia coli (64/89) and Klebsiella pneumoniae (16/89). PCR and sequencing showed that 98.8% (87/89) of ESBL-PE harbored bla CTX-M genes: bla CTX-M-15 in 94.25% (82/87) and bla CTX-M-14 in 5.75% (5/87). Phylogroup determination by quadruplex PCR indicated that ESBL-producing E. coli isolates belonged to group A (n = 17; 27%), C (n = 17; 27%), B2 (n = 9; 14%), B1 (n = 8; 13%), D (n = 8; 13%), E (n = 1; 1.6%), and F (n = 1; 1.6%). The ST131 clone was identified in 100% (9/9) of E. coli B2 strains. Conclusions: The high fecal carriage rate of ESBL-PE associated with CTX-M-15 in hospital and community settings of Chad highlights the risk for resistance transmission between non-pathogenic and pathogenic bacteria.Ítem High prevalence and characterization of extended-spectrum ß-lactamase producing Enterobacteriaceae in Chadian hospitals(BMC Infectious Diseases, 2019-02-28) Ouchar Mahamat, Oumar; Lounnas, Manon; Hide, Mallorie; Dumont, Yann; Tidjani, Abelsalam; Kamougam, Kadidja; Abderrahmane, Madina; Benavides, Julio; Solasso, Jérôme; Bañuls, Anne-Laure; Jean-Pierre, Hélène; Carrière, Christian; Godreuil, SylvainBackground: Extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-PE) represent a major problem in the management of nosocomial infections. However, ESBL-PE are not systematically monitored in African countries. The aim of this study was to determine ESBL-PE prevalence in patients from three hospitals in N'Djamena, the capital city of Chad, and to characterize the genetic origin of the observed resistance. Methods: From January to March 2017, 313 non-duplicate isolates were recovered from various clinical specimens obtained from 1713 patients in the three main hospitals of N'Djamena. Bacterial species were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Susceptibility to 28 antibiotics was tested using the disk diffusion method on Müller-Hinton agar, and ESBL production was confirmed with the double-disc synergy test. The most prevalent ESBL genes associated with the observed resistance were detected using multiplex PCR followed by double-stranded DNA sequencing. Results: Among the 313 isolates, 197 belonged to the Enterobacteriaceae family. The overall ESBL-PE prevalence was 47.72% (n = 94/197), with a higher rate among inpatients compared with outpatients (54.13% vs. 34.37%). ESBL-PE prevalence was highest in older patients (≥60 years of age). E. coli was the most common ESBL-producer organism (63.8%), followed by K. pneumoniae (21.2%). ESBL-PE were mainly found in urine samples (75%). The CTX-M-1 group was dominant (96.7% of the 94 ESBL-PE isolates, CTX-M-15 enzyme), followed by the CTX-M-9 group (4.1%). 86% of resistant isolates harbored more than one ESBL-encoding gene. ESBL production was also associated with the highest levels of resistance to non-β-lactam drugs. Conclusions: The prevalence of ESBL-PE harboring resistant genes encoding ESBLs of the CTX-M-1 group was high (48%) among clinical isolates of three main hospitals in Chad, suggesting an alarming spread of ESBL-PE among patients.Ítem Long-Term Interactions of Salmonella Enteritidis With a Lytic Phage for 21 Days in High Nutrients Media(Frontiers Media S.A., 2022-05) Barron Montenegro, Rocio; Rivera, Dácil; Serrano, María Jesus; García, Rodrigo; Álvarez, Diana M.; Benavides, Julio; Arredondo, Fernanda; Álvarez, Francisca P.; Bastías, Roberto; Ruiz, Soledad; Hamilton West, Christopher; Castro Nallar, Eduardo; Moreno Switt, Andrea I.Salmonella spp. is a relevant foodborne pathogen with worldwide distribution. To mitigate Salmonella infections, bacteriophages represent an alternative to antimicrobials and chemicals in food animals and food in general. Bacteriophages (phages) are viruses that infect bacteria, which interact constantly with their host. Importantly, the study of these interactions is crucial for the use of phages as a mitigation strategy. In this study, experimental coevolution of Salmonella Enteritidis (S. Enteritidis) and a lytic phage was conducted in tryptic soy broth for 21 days. Transfer to fresh media was conducted daily and every 24 hours, 2 mL of the sample was collected to quantify Salmonella OD600 and phage titter. Additionally, time-shift experiments were conducted on 20 colonies selected on days 1, 12, and 21 to evaluate the evolution of resistance to past (day 1), present (day 12), and future (day 21) phage populations. The behavior of the dynamics was modeled and simulated with mathematical mass-action models. Bacteria and phage from days 1 and 21 were sequenced to determine the emergence of mutations. We found that S. Enteritidis grew for 21 days in the presence and absence of the phage and developed resistance to the phage from day 1. Also, the phage was also able to survive in the media for 21 days, however, the phage titer decreased in approx. 3 logs PFU/mL. The stability of the lytic phage population was consistent with the leaky resistance model. The time-shift experiments showed resistance to phages from day 1 of at least 85% to the past, present, and future phages. Sequencing of S. Enteritidis showed mutations in genes involved in lipopolysaccharide biosynthesis genes rfbP and rfbN at day 21. The phage showed mutations in the tail phage proteins responsible for recognizing the cell surface receptors. These results suggest that interactions between bacteria and phage in a rich resource media generate a rapid resistance to the infective phage but a fraction of the population remains susceptible. Interactions between Salmonella and lytic phages are an important component for the rational use of phages to control this important foodborne pathogen. Copyright © 2022 Barron-Montenegro, Rivera, Serrano, García, Álvarez, Benavides, Arredondo, Álvarez, Bastías, Ruiz, Hamilton-West, Castro-Nallar and Moreno-Switt.Ítem Spread of NDM-5 and OXA-181 carbapenemase-producing Escherichia coli in Chad(Antimicrobial Agents and Chemotherapy, 2019) Mahamat, Oumar Ouchara; Lounnas, Manona; Hide, Mallorie; Tidjani, Abelsalam; Benavides, Julio; Diack, Abibatou; Somasse, Calèbe; Gamougam, Kadidjaf; Carrière, Christian; Decré, Dominique; Bañuls, Anne-Laure; Jean-Pierre, HélèneWe detected for the first time blaNDM-5 and blaOXA-181 in Escherichia coli isolates from hospitalized patients and healthy volunteers in Chad. These resistance genes were located on IncX3 and IncF plasmids. Despite the large diversity of E. coli clones, the identified resistant intestinal isolates belonged mainly to the same sequence type. Copyright © 2019 American Society for Microbiology. All Rights Reserved.