[Identification and antibiotic susceptibility of Aeromonas spp. in a University Hospital in the city of Buenos Aires].

Aeromonas spp. are opportunistic pathogens that cause both intra- and extraintestinal infections. The objective of this work was the phenotypic and genotypic characterization of a collection of Aeromonas strains, in addition to determining their sensitivity to different antimicrobials.

[Atypical non-Typhi Salmonella enterica bacteremia, lactose-positive, lysine decarboxylase-negative].

We describe here the first isolation in Argentina of a lactose-fermenting and lysine decarboxylase-negative non-Typhi Salmonella enterica from a blood culture of a patient with systemic lupus erythematosus. The microorganism was identified as S. enterica (score: 2.

NDM-5-producing Klebsiella pneumoniae ST258 in a university hospital in Argentina.

Background: A drastic increase in carbapenem resistance among Klebsiella pneumoniae isolates occurred during the period 2019-22. Three epidemiological changes could be evidenced: (i) NDM became the predominant carbapenemase; (ii) NDM-5 replaced NDM-1; and (iii) the emergence of NDM-producing K. pneumoniae ST258 (NDM-KpST258).

First report of abdominal sepsis caused by a recently described species: Chimaeribacter arupi.

We present a case of a 34-year-old patient with abdominal sepsis caused by an infrequent species: Chimaeribacter arupi. Genomic analysis confirmed the identification which is difficult to achieve by other methods so far. To our knowledge, this represents the first case of infection by this species reported in Argentina.

spp: the emergence of a new genus of healthcare-associated Enterobacterales encoding carbapenemases in Argentina: a case series.

Members of the genus (order ) are isolated from the natural environment and clinical settings. Identification of strains based on biochemical characteristics is complicated due to taxonomic confusion, and they are often misidentified by automated identification systems in laboratories. In this study we describe the first three clinical cases associated with spp.

MALDI-TOF MS-Based KPC Direct Detection from Patients' Positive Blood Culture Bottles, Short-Term Cultures, and Colonies at the Hospital.

Carbapenemase resistance in is a global public health problem and rapid and effective methods for detecting these resistance mechanisms are needed urgently. Our aim was to evaluate the performance of a MALDI-TOF MS-based " carbapenemase" (KPC) detection protocol from patients' positive blood cultures, short-term cultures, and colonies in healthcare settings. Bacterial identification and KPC detection were achieved after protein extraction with organic solvents and target spot loading with suitable organic matrices.

Interspecies interactions in mixed-species biofilms formed by and gram-negative bacteria isolated from polymicrobial diabetic foot ulcers.

Diabetic foot ulcers (DFU) are exacerbated by bacterial colonisation. Here, a high prevalence of was observed in DFU patients from an Argentinean hospital. was frequently co-isolated with , , and .

First nosocomial outbreak of SME-4-producing Serratia marcescens in South America.

Carbapenemase-producing-Serratia marcescens isolates, although infrequent, are considered important nosocomial pathogens due to their intrinsic resistance to polymyxins, which limits therapeutic options. We describe a nosocomial outbreak of SME-4-producing S. marcescens in Buenos Aires city which, in our knowledge, represents the first one in South America.

Discrimination of the chemotherapy resistance status of human leukemia and glioblastoma cell lines by MALDI-TOF-MS profiling.

Chemotherapy mistreatment is partially due to a lack of rapid and reliable tools to discriminate between sensitive and resistant phenotypes. In many cases, the resistance mechanism is not fully understood, contributing to the diagnostic tools' absence. This work aims to determine the capacity of MALDI-TOF-MS profiling to discriminate between chemotherapy-resistant and sensitive phenotypes in leukemia and glioblastoma cells.

Corynebacterium guaraldiae sp. nov.: a new species of Corynebacterium from human infections.

Non-diphtheria Corynebacterium species (NDC) belonging to the human skin and mucosa microbiota are frequently neglected as contaminants. However, reports of human infections by Corynebacterium spp. have increased considerably in recent years.

[Actinomyces europaeus (Gleimia europaea) associated with brain abscess: A report of three cases].

A brain abscess is a focal infection characterized by a collection of pus in the brain parenchyma. It is a life-threatening condition that should be diagnosed and treated as soon as possible. We report here three cases of patients with otogenic brain abscesses of polymicrobial origin that had in common the isolation of Actinomyces europaeus, which has not been previously described in this location.

[Vibrio vulnificus infection of the skin and soft parts. Communication of a case diagnosed in Argentina].

Vibrio vulnificus is one of the most virulent Vibrio species known. It is a bacterium with universal distribution. The first case registered in Uruguay occurred in 2001 and, since then, several infections have occurred per year.

Peptidome profiling for the immunological stratification in sepsis: a proof of concept study.

Sepsis has been called the graveyard of pharmaceutical companies due to the numerous failed clinical trials. The lack of tools to monitor the immunological status in sepsis constrains the development of therapies. Here, we evaluated a test based on whole plasma peptidome acquired by MALDI-TOF-mass spectrometer and machine-learning algorithms to discriminate two lipopolysaccharide-(LPS) induced murine models emulating the pro- and anti-inflammatory/immunosuppression environments that can be found during sepsis.

[Description of a case of abdominal sepsis due to Desulfovibrio desulfuricans].

Desulfovibrio spp. are strict anaerobes that are ubiquitous in nature. They can reside in the human or animal gastrointestinal tract and, as they are also environmental bacteria, may be present in soil and water.

[Empyema necessitatis caused by Campylobacterrectus. Rapid identification by MALDI-TOF MS].

Empyema necessitatis (EN) is a very rare complication of a pleural empyema, in which the infection extends to adjacent soft tissues. Anaerobic bacteria are very rare etiologic agents of EN, which occurs in the course of chronic infections. We present the first case of empyema necessitatis caused by Campylobacter rectus.

Characterisation of blaharbouring plasmids recovered from Pseudomonas aeruginosa ST654 and ST235 high-risk clones.

Objective: The main objectives were to describe two bla plasmids recovered from Pseudomonas aeruginosa isolates belonging to the ST654 and ST235 high-risk clones, and to compare with complete sequences of bla harbouring plasmids available in public databases.

Methods: Antimicrobial susceptibility was determined according to CLSI (Clinical and Laboratory Standards Institute) guidelines. Genomes were sequenced using an Illumina MiSeq platform, and bla plasmid sequences were achieved using MinION platform.

Molecular and Phenotypic Characterization of a Multidrug-Resistant Coproducing OXA-232 and MCR1.1 in Argentina.

The spread of arbapenem-resistant Enterobacterales has raised concern in clinical settings due to the limited therapeutic options available. OXA-48-like enzymes are still sporadic in South America. The aim of this study was to characterize a multidrug-resistant isolate from a hospitalized patient in Buenos Aires city.

[Dolosigranulum pigrum in corneal abscess].

Dolosigranulum pigrum is a gram-positive, facultatively anaerobic coccus, which is part of the oral and upper respiratory tract microbiota. Although reports of infections by this microorganism are scarce, it has been associated with a wide spectrum of infectious diseases. The case of an elderly man with a lower corneal abscess, in which Dolosigranulum pigrum was isolated, is described.

Growth conditions affect biofilms of producing mastitis: Contribution of MALDI-TOF-MS to strain characterization.

Bovine mastitis is a disease of dairy cattle prevalent throughout the world that causes alterations in the quality and composition of milk, compromising technological performance. is one of the most important pathogens that produce clinical, subclinical, and chronic mastitis. Biofilms are considered a virulence factor necessary for the survival of in the mammary gland.

synergistic activity of aztreonam (AZT) plus novel and old β-lactamase inhibitor combinations against metallo-β-lactamase-producing AZT-resistant .

The emergence of metallo-β-lactamase (MBL)-producing , mainly New Delhi metallo-β-lactamase (NDM), represents a clinical threat due to the limited therapeutic alternatives. Aztreonam (AZT) is stable to MBLs, but most MBL-producing isolates usually co-harbour other β-lactamases that confer resistance to AZT and, consequently, its use is restricted in these isolates. We compared the ability of sulbactam (SUL), tazobactam (TAZ), clavulanic acid (CLA) and avibactam (AVI) to restore the AZT activity in MBL-producing AZT-resistant isolates.

Infections due to Vagococcus spp. Microbiological and clinical aspects and literature review.

Introduction: An increase in recent years in the isolation of Vagococcus spp. is suggestive of emerging infection by this pathogen in our hospital.

Methods: Prospective, descriptive study.

- a rare species isolated from a urine sample.

spp. are Gram-positive rods that are recognized to cause opportunistic diseases under certain predisposing clinical conditions. Some species have been described in urinary tract infections.

Role of Tonsillar Chronic Inflammation and Commensal Bacteria in the Pathogenesis of Pediatric OSA.

Immune responses at the boundary between the host and the world beyond are complex and mucosal tissue homeostasis relies on them. Obstructive sleep apnea (OSA) is a syndrome suffered by children with hypertrophied tonsils. We have previously demonstrated that these tonsils present a defective regulatory B cell (Breg) compartment.