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.

Feeding on soybean crops changed gut bacteria diversity of the southern green stinkbug (Nezara viridula) and reduced negative effects of some associated bacteria.

Background: The southern green stinkbug (Nezara viridula) is a mayor pest of soybean. However, the mechanism underlying stinkbug resistance to soybean defenses is yet ignored. Although gut bacteria could play an essential role in tolerating plant defenses, most studies testing questions related to insect-plant-bacteria interactions have been performed in laboratory condition.

Molecular characterization and antimicrobial resistance profiles of Salmonella Heidelberg isolates from poultry.

In the last 10 years, Salmonella Heidelberg has been extensively isolated from poultry in several countries. In this context, molecular characterization is essential to understand whether the strains have entered the farms from a single or several sources. Thus, the aim of this study was to determine the genetic relationship and antimicrobial susceptibility of S.

Phenotypic Detection of Plasmid-Mediated Colistin Resistance in .

The aim of this work was to evaluate an easy-to-perform assay based upon inhibition of mobile colistin resistance (MCR) activity by EDTA. We included 92 nonrelated isolates of (74 , 17 , and 1 ). Our proposed method is based on a modification of the colistin agar-spot screening test (CAST), a plate containing 3 μg/ml colistin, by adding an extra plate of colistin agar-spot supplemented with EDTA (eCAST).

Simultaneous Carriage of and Other Antimicrobial Resistance Determinants in From Poultry.

The use of antimicrobial growth promoters (AGPs) in sub-therapeutic doses for long periods promotes the selection of resistant microorganisms and the subsequent risk of spreading this resistance to the human population and the environment. Global concern about antimicrobial resistance development and transference of resistance genes from animal to human has been rising. The goal of our research was to evaluate the susceptibility pattern to different classes of antimicrobials of colistin-resistant from poultry production systems that use AGPs, and characterize the resistance determinants associated to transferable platforms.

Characterized non-transient microbiota from stinkbug (Nezara viridula) midgut deactivates soybean chemical defenses.

The Southern green stinkbug (N. viridula) feeds on developing soybean seeds in spite of their strong defenses against herbivory, making this pest one of the most harmful to soybean crops. To test the hypothesis that midgut bacterial community allows stinkbugs to tolerate chemical defenses of soybean developing seeds, we identified and characterized midgut microbiota of stinkbugs collected from soybean crops, different secondary plant hosts or insects at diapause on Eucalyptus trees.

First survey on antibiotic resistance markers in Enterobacteriaceae in Cochabamba, Bolivia.

A molecular survey was conducted in Cochabamba, Bolivia, to characterize the mechanism involved in the resistance to clinically relevant antibiotics. Extended Spectrum β-lactamase encoding genes and plasmid-mediated quinolone resistance (PMQR) markers were investigated in a total of 101 oxyimino-cephalosporin-resistant enterobacteria recovered from different health centers during four months (2012-2013). CTX-M enzymes were detected in all isolates, being the CTX-M-1 group the most prevalent (88.

Antibiotic resistance and integrons in Shiga toxin-producing Escherichia coli (STEC).

Shiga toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis (HC) and hemolytic-uremic syndrome in humans (HUS). Cattle are the main reservoir of STEC and transmission to humans occurs through contaminated food and water. Antibiotics are used in pig production systems to combat disease and improve productivity and play a key role in the dissemination of antibiotic resistance genes to the bacteria.

β-lactamases produced by amoxicillin-clavulanate-resistant enterobacteria isolated in Buenos Aires, Argentina: a new blaTEM gene.

Resistance to β-lactam/β-lactamase inhibitors in enterobacteria is a growing problem that has not been intensively studied in Argentina. In the present work, 54/843 enterobacteria collected in a teaching hospital of Buenos Aires city were ampicillin-sulbactam-resistant isolates remaining susceptible to second- and third-generation cephalosporins. The enzymatic mechanisms present in the isolates, which were also amoxicillin-clavulanic acid (AMC)-resistant (18/54) were herein analyzed.

First isolate of KPC-2-producing Klebsiella pneumonaie sequence type 23 from the Americas.

KPC-2-producing Klebsiella pneumoniae isolates mainly correspond to clonal complex 258 (CC258); however, we describe KPC-2-producing K. pneumoniae isolates belonging to invasive sequence type 23 (ST23). KPC-2 has scarcely been reported to occur in ST23, and this report describes the first isolation of this pathogen in the Americas.

First detection of CMY-2 plasmid mediated β-lactamase in Salmonella Heidelberg in South America.

Salmonella enterica serovar Heidelberg ranks among the most prevalent causes of human salmonellosis in the United States and Canada, although it has been infrequently reported in South American and European countries. Most Salmonella infections are self-limiting; however, some invasive infections require antimicrobial therapy. In this work we characterized an oxyimino-cephalosporin resistant S.

[Two multidrug-resistant Salmonella infantis isolates behave like hypo-invasive strains but have high intracellular proliferation].

In this work, plasmid-encoded virulence factors in two Salmonella Infantis isolates carrying multiresistance plasmids were investigated. In addition, their invasion and proliferative ability in non-phagocytic cells was studied. None of them showed the typical determinants of virulence plasmids (spy operon).

β-lactamase-mediated resistance: a biochemical, epidemiological and genetic overview.

Early after the introduction of the first (narrow spectrum) penicillins into clinical use, penicillinase-producing staphylococci replaced (worldwide) the previously susceptible microorganisms. Similarly, the extensive use of broad-spectrum, orally administered β- lactams (like ampicillin, amoxicillin or cefalexin) provided a favorable scenario for the selection of gram-negative microorganisms producing broad spectrum β-lactamases almost 45 years ago. These microorganisms could be controlled by the introduction of the so called "extended spectrum cephalosporins".

First human isolate of Salmonella enterica serotype Enteritidis harboring blaCTX-M-14 in South America.

We studied a clinical isolate of Salmonella enterica serotype Enteritidis showing resistance to oxyiminocephalosporins. PCR analysis confirmed the presence of bla(CTX-M-14) linked to IS903 in a 95-kb IncI1 conjugative plasmid. Such a plasmid is maintained on account of the presence of a pndAC addiction system.

Identification of the full set of Listeria monocytogenes penicillin-binding proteins and characterization of PBPD2 (Lmo2812).

Background: Bacterial penicillin-binding proteins (PBPs) can be visualized by their ability to bind radiolabeled or fluorescent β-lactam derivatives both whole cells and membrane/cell enriched fractions. Analysis of the Listeria monocytogenes genome sequence predicted ten genes coding for putative PBPs, but not all of their products have been detected in studies using radiolabeled antibiotics, thus hindering their characterization. Here we report the positive identification of the full set of L.

[Comparison of three microbiological methods for detection of expanded-spectrum betalactamases in Enterobacteriaceae isolated in Santa Fe (Argentina)].

Introduction: Expanded-spectrum betalactamases (ESBLs) are the main source of resistance to oxyimino cephalosporins and monobactams in Enterobacteriaceae. Most of them derive from TEM or SHV, however the incidence of other families like CTX-M, OXA and PER has increased. In Argentina, the most frequent ESBL in Enterobacteriaceae is CTX-M-2.

Transcriptional analysis of the bla(CTX-M-2) gene in Salmonella enterica serovar Infantis.

Transcriptional organization of bla(CTX-M-2) present in a multiresistance plasmid of Salmonella enterica serovar Infantis suggests the presence of more than one promoter involved in the expression of the beta-lactamase gene. At least two bla(CTX-M-2)-specific mRNAs (near to 1 kb and 5 kb) were evidenced. Two +1 signals were detected at -22 bp and -59 bp of bla(CTX-M-2) defining two putative promoters.

Genetic and phenotypic characterization of resistance to macrolides in Streptococcus pyogenes from Argentina.

Five hundred and seventy-eight strains of group A streptococci (GAS) isolated mostly from paediatric pharyngeal swabs were tested to evaluate their susceptibility to erythromycin. Resistant strains were then tested for their MICs to erythromycin and clindamycin, their phenotype of resistance to macrolides-lincosamides-streptogramin (MLS(B)) and for the presence of macrolide resistance genes. The rate of resistance to erythromycin was 8.