Revisiting typing systems for group B prophages: an application in prophage detection and classification in group B isolates from Argentina.

Group B (GBS) causes severe infections in neonates and adults with comorbidities. Prophages have been reported to contribute to GBS evolution and pathogenicity. However, no studies are available to date on the presence and diversity of prophages in GBS isolates from humans in South America.

Genetic and Phenotypic Changes Related to the Development of -Independent Oxacillin Non-Susceptibility in ST8 Recovered after Antibiotic Therapy in a Patient with Bacteremia.

The -independent oxacillin non-susceptible (MIONSA) strains represent a great clinical challenge, as they are not easily detected and can lead to treatment failure. However, the responsible molecular mechanisms are still very little understood. Here, we studied four clinical ST8-MSSA- isolates recovered during the course of antibiotic treatment from a patient suffering successive episodes of bacteremia.

The Changing Epidemiology and Antimicrobial Susceptibility of Isolated from Blood Cultures in a University Hospital from Argentina.

bacteremia (SAB) is one of the most common serious bacterial infections worldwide. In this study, we demonstrated changes in SAB epidemiology in an Argentinean University Hospital during an 8-year period (2009-2016). A total of 326 clinical isolates were recovered in three periods: P1: 2009-2010, P2: 2012-2014, and P3: 2015-2016.

Genomic epidemiology of isolated from bloodstream infections in South America during 2019 supports regional surveillance.

remains one of the leading causes of infections worldwide and a common cause of bacteraemia. However, studies documenting the epidemiology of in South America using genomics are scarce. We hereby report on the largest genomic epidemiology study to date of both methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) in South America, conducted by the StaphNET-SA network.

[Primary pneumococcal peritonitis in a pediatric hospital from Argentina].

Pneumococcal peritonitis represents a small subset of patients suffering from invasive pneumococcal disease (IPD). We describe 5 cases of primary peritonitis documented in the pediatric hospital over 15 years (2005-2020) of IPD surveillance. The patients, 3girls and 2boys with a mean age of 5 years, experienced peritoneal signs and symptoms; 3of them suffered from nephrotic syndrome.

Comparative Genomics Identifies Novel Genetic Changes Associated with Oxacillin, Vancomycin and Daptomycin Susceptibility in ST100 Methicillin-Resistant .

Infections due to vancomycin-intermediate (VISA) and heterogeneous VISA (hVISA) represent a serious concern due to their association with vancomycin treatment failure. However, the underlying molecular mechanism responsible for the hVISA/VISA phenotype is complex and not yet fully understood. We have previously characterized two ST100-MRSA-hVISA clinical isolates recovered before and after 40 days of vancomycin treatment (D1 and D2, respectively) and two in vitro VISA derivatives (D23C9 and D2P11), selected independently from D2 in the presence of vancomycin.

Antimicrobial resistance studies in staphylococci and streptococci isolated from cows with mastitis in Argentina.

Background: and are the main cause of clinical mastitis in dairy cattle in Argentina, whereas coagulase-negative staphylococci (CNS) and environmental streptococci are the main cause of subclinical mastitis. Bacteria isolated from infected animals show increasing antimicrobial resistance.

Objectives: This study aims to determine the antimicrobial resistance of staphylococci and streptococci isolated from milk with mastitis, and to genotypically characterize the methicillin-resistant (MR) staphylococci.

Beta-lactam antibiotics and viridans group streptococci.

The aim of this review is to present an update on the susceptibility of viridans group streptococci (VGS) to β-lactam antimicrobials, with emphasis on the Argentinean scenario. VGS are a heterogeneous group including five groups of species, each one exhibiting peculiar susceptibility patterns to penicillin (PEN). Species of the Streptococcus mitis group are frequently nonsusceptible to PEN.

Epidemiology of Invasive Infections Caused by in Argentina.

In recent years, an increase in the number of cases of invasive infections due to (group B [GBS]) in adults has been reported. During 2014 and 2015, a multicentric, observational, and prospective study, including 40 health centers, was developed to describe the phenotypic and genotypic characteristics of GBS isolates circulating in Argentina and to analyze the clinical and demographic characteristics of patients with invasive infections. We recovered 162 invasive (GBSi) isolates from adult patients ( = 130, 80.

Resistance to β-lactams in Streptococcus pneumoniae.

Streptococcus pneumoniae is an important causal agent of pneumonia, meningitis, sepsis, bacteremia, and otitis media. Penicillin resistance rates in S. pneumoniae have remained stable in Argentina in the last years.

Genomic Epidemiology of CC30 Methicillin-Resistant Staphylococcus aureus Strains from Argentina Reveals Four Major Clades with Distinctive Genetic Features.

clonal complex 30 (CC30) has given rise to epidemics worldwide and is one of the most prevalent lineages in Argentina, represented by sequence type 30 methicillin-resistant SCC type IV (ST30-MRSA-IV). ST30-MRSA-IV has displaced previous prevalent clones in the country and demonstrated increased virulence. Despite the burden of infections caused by ST30-MRSA-IV both in hospitals and in communities in Argentina, no detailed genome-based characterization of this clone is available to date.

Comparative genomics of ST5 and ST30 methicillin-resistant sequential isolates recovered from paediatric patients with cystic fibrosis.

chronic airway infection in patients with cystic fibrosis (CF) allows this pathogen to adapt over time in response to different selection pressures. We have previously shown that the main sequence types related to community-acquired methicillin-resistant (MRSA) infections in Argentina - ST5 and ST30 - are also frequently isolated from the sputum of patients with CF, but in these patients they usually display multi-drug antimicrobial resistance. In this study, we sequenced the genomes of MRSA from four paediatric CF patients with the goal of identifying mutations among sequential isolates, especially those possibly related to antimicrobial resistance and virulence, which might contribute to the adaptation of the pathogen in the airways of patients with CF.

Genetic changes associated with tigecycline resistance in Staphylococcus aureus in vitro-selected mutants belonging to different lineages.

Tigecycline (TGC) resistance remains rare in Staphylococcus aureus worldwide. In this study, 12 TGC-resistant S. aureus mutants (TRSAm) were obtained displaying an increase in efflux activity.

[Pneumococcal osteoarticular infections in children admitted to a Pediatric Reference Hospital from Misiones, Argentina. Thirteen years of surveillance].

Streptococcus pneumoniae is a rare cause of osteoarticular infections. We describe 5documented cases that occurred in 2005, 2009, 2011, 2015 and 2017 in patients admitted to the Pediatric Provincial Reference Hospital of Misiones. These cases corresponded to a 4-year-old boy and 4 girls aged 11, 10, 6 years and 4 months with a diagnosis of osteomyelitis of the scapula and humerus, arthritis of the hip, ankle and osteomyelitis of the distal fibula.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) clones from Paraguayan children.

Introduction: Staphylococcus aureus is considered one of the most important human pathogens, and its levels of resistance to methicillin have increased even in strains isolated from people without nosocomial risk factors. Molecular analysis is essential for understanding the patterns of dissemination. The objective of this study was to identify community-acquired methicillin-resistant S.

Argentinian multicenter study on urinary tract infections due to Streptococcus agalactiae in adult patients.

Introduction: Streptococcus agalactiae (group B streptococcus, GBS) is a recognized urinary pathogen both in males and pregnant or non-pregnant women. Data regarding GBS serotypes recovered from urinary tract infections (UTIs) are scarce. The aim of this study was to describe the clinical and microbiological characteristics of UTIs caused by GBS in adult patients in Argentina.

[Neisseria meningitidis isolated from patients in men who have sex with men].

During the periods 2000-2004 and 2014-2015, Neisseria meningitidis was investigated in men who have sex with men, 1143 and 544 respectively, who consulted in the sexually-transmitted disease program. Prevalence, serogroup distribution and susceptibility to antibiotics were determined. Pharyngeal, rectal and urethral swabs were cultivated on selective Thayer-Martin modified medium.

Fluoroquinolone-Resistant Invasive Isolates Recovered in Argentina.

or group B (GBS) is an important pathogen in neonates and nonpregnant individuals. Epidemiological studies of GBS resistance to fluoroquinolones (FQs) in Latin America are scarce. This study aimed to determine the local prevalence of FQ resistance in the frame of a national, prospective multicenter study of invasive GBS infections and to investigate mechanisms of resistance, serotype distribution, and clonal relationships among resistant isolates.

First isolation of a methicillin-resistant from bovine mastitis in Argentina.

This research communication describes the first isolation of a methicillin-resistant (MRSA) from cow's mastitic milk in Argentina. Bovine mastitis causes important economic losses in the dairy industry and the most commonly isolated bacteria from bovine mastitis are . The A gene present in MRSA bacteria confers resistance to almost all -lactam antibiotics, the most frequent drugs used in bovine mastitis therapy.

[Susceptibility of Streptococcus pyogenes isolated from invasive infections to trimethoprim-sulfamethoxazole].

It is erroneously believed that group A streptococci (GAS) are universally resistant to trimethoprim-sulfamethoxazole (TMS). This is mainly because media commonly used for in vitro determination of susceptibility to antibiotics contain thymidine, a nucleoside that antagonizes the antibiotic effect of TMS. The objective of this work was to determine EGA sensitivity to TMS in the presence and absence of thymidine.

Resistance to β-lactams in enterococci.

Enterococci are intrinsically resistant to several antimicrobial classes and show a great ability to acquire new mechanisms of resistance. Resistance to β-lactam antibiotics is a major concern because these drugs either alone or in combination are commonly used for the treatment of enterococcal infections. Ampicillin resistance, which is rare in Enterococcus faecalis, occurs in most of the hospital-associated Enterococcus faecium isolates.

TNFR1 Signaling Contributes to T Cell Anergy During Sepsis.

Early research on sepsis has focused on the initial hyper-inflammatory, cytokine mediated phase of the disorder whereas the events that govern the concomitant and subsequent anti-inflammatory compensatory response are not completely understood. In this context, the putative participation of TNFR1-mediated signaling in the immunosuppressive phase of sepsis has not been elucidated. The aim of this study was to determine the role of TNFR1 in directing the immune dysfunction during sepsis and the potential contribution of MDSC to this process.

Susceptibility to β-lactams in β-hemolytic streptococci.

Group A (GAS), B (GBS), C (GCS) and G (GGS) β-hemolytic streptococci are important human pathogens. They cause infections of different severity and frequency. Nowadays, after 70 years of use, penicillin is still universally active against GAS, GCS and GGS.

Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Cystic Fibrosis Patients from Argentina.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization in cystic fibrosis (CF) patients is an increasing problem in many countries. In our Respiratory Center at the Hospital de Niños "Dr. Ricardo Gutiérrez", Buenos Aires, Argentina, the prevalence has climbed from 23% in 1995 up to 32% in 2011.

High virulence of methicillin resistant Staphylococcus aureus ST30-SCCmecIVc-spat019, the dominant community-associated clone in Argentina.

Community-acquired methicillin resistant Staphylococcus aureus emerged as a worldwide health problem in the last few years. In Argentina, it is found in 70% of skin and skin structure infections in previously healthy adult patients and causes severe invasive diseases. The ST30-SCCmecIVc-spat019 clone is predominant in adult infections and has displaced the previously prevalent ST5-SCCmecIVa-spat311 clone in community settings.