João Pedro Rueda Furlan

Presence of β-Lactamases Encoding Genes in Soil Samples from Different Origins

The functional classification of β-lactamases is done through assessing their ability to hydrolyze specific β-lactams and its inactivation by inhibitors. This study investigated the β-lactamases encoding genes present in soil samples from different origins (landfill, preservation area, and soil from a farm). Genes codifying for ESBL enzymes blaSHV, blaTEM-116 and blaOXA-1 were found in all analyzed samples. Gene for ESBL blaCTX-M-14 was detected in the landfill and farm soil samples, but they were not found in the preservation area, while blaOXA-48-like was present just in the soil from the landfill. The gene for the MBL blaVIM was found in the soil sample from a farm. The results indicate that blaSHV, blaTEM-116, and blaOXA-1 genes are scattered in soils with and without potential contaminants; however, genes blaCTX-M-14, blaOXA-48, and blaVIM were detected just in polluted areas.

Mutations in NalC induce MexAB-OprM overexpression resulting in high level of aztreonam resistance in environmental isolates of Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen with high resistance to a wide variety of antimicrobials. The multidrug resistance pump MexAB-OprM promotes the efflux of various antibiotics, mostly when mutations accumulate in the transcriptional regulators MexR, NalC and NalD, thereby causing MexAB-OprM overexpression. In this work, a characterization of 50 P. aeruginosa isolates obtained from Brazilian agricultural soils to determine the reasons of their resistance to aztreonam was done. The majority of the isolates showed higher aztreonam resistance than wild-type strain by MIC method. DNA sequence analysis of mexR, nalC and nalD genes from 13 of these isolates showed the amino acid substitution in NalC for all tested isolates, just one mutation was detected in MexR and none in NalD. Furthermore, an increase in the level of mexA expression by real-time RT-PCR analysis in eight isolates harboring mutations in NalC was found. Although there was not a relationship between MIC of aztreonam and the level of mexA expression, on the other hand, the results presented here suggest that novel mutations in NalC, including Arg97-Gly and Ala186-Thr, are related to MexAB-OprM overexpression causing aztreonam resistance in P. aeruginosa environmental isolates.

Importance of Sequencing To Determine Functional bla(TEM) Variants

According to Jacoby and Bush, TEM-116 extended-spectrum beta-lactamase is now a naturally occurring enzyme ([1][1]). In 2005, Chiang and collaborators described the possibility of commercial Taq polymerase contamination with bla TEM-1 gene ([2][2]). One year later, Song et al. demonstrated the

Spread of multidrug-resistant high-risk Klebsiella pneumoniae clones in a tertiary hospital from southern Brazil

Klebsiella pneumoniae is among the most important pathogens found in hospitals. The emergence of multiple antibiotic resistant K. pneumoniae associated with its virulence factors is a worldwide concern and its early identification is crucial, especially for controlling the spread of emerging clones. This article reports a high prevalence of multiresistant K. pneumoniae in a university hospital in southern Brazil, harboring several virulence and β-lactamase encoding genes, including pandrug-resistant high-risk international clones belonging to the clonal group 258 (ST11, ST15, ST101, ST258, ST340 and ST874).

Detection of blaNDM-1 in Stenotrophomonas maltophilia isolated from Brazilian soil

This study reports the presence of the bla NDM-1 gene in an isolate of Stenotrophomonas maltophilia obtained from a Brazilian soil, inside an IncA/C plasmid with ~ 45 Kb. To the best of our knowledge, this is the second report in the world and the first in Brazil of NDM-producing bacterium isolated from soil.

Detection of β-lactamase encoding genes in feces, soil and water from a Brazilian pig farm

Abstractβ-lactam antibiotics are widely used for the treatment of different types of infections worldwide and the resistance to these antibiotics has grown sharply, which is of great concern. Resistance to β-lactams in gram-negative bacteria is mainly due to the production of β-lactamases, which are classified according to their functional activities. The aim of this study was to verify the presence of β-lactamases encoding genes in feces, soil, and water from a Brazilian pig farm. Different β-lactamases encoding genes were found, including blaCTX-M-Gp1, blaCTX-M-Gp9, blaSHV, blaOXA-1-like, blaGES, and blaVEB. The blaSHV and blaCTX-M-Gp1 genes have been detected in all types of samples, indicating the spread of β-lactam resistant bacteria among farm pigs and the environment around them. These results indicate that β-lactamase encoding genes belonging to the cloxacillinase, ESBL, and carbapenemase and they have high potential to spread in different sources, due to the fact that genes are closely related to mobile genetic elements, especially plasmids.

High-level of resistance to β-lactam and presence of β-lactamases encoding genes in Ochrobactrum sp. and Achromobacter sp. isolated from soil

OBJECTIVES Bacteria belonging to the genera Ochrobactrum and Achromobacter are bacteria considered opportunistic, causing infections mainly in immunocompromised patients. β-lactamases are the main cause of resistance to β-lactam antibiotics. This study aimed to investigate the antimicrobial resistance profile and the presence of β-lactamases encoding genes in Ochrobactrum sp. and Achromobacter sp. isolated from Brazilian soils. METHODS Soil samples from the five regions of Brazil were collected for the isolation of bacteria, which were identified molecularly and then, the minimum inhibitory concentration and detection of β-lactamases encoding genes were performed. RESULTS High-level of resistance to β-lactam antibiotics and different β-lactamases encoding genes were found (blaCTX-M-Gp1, blaSHV, blaOXA-1-like and blaKPC), including the first report of the presence of blaKPC in bacteria belonging to the genera Ochrobactrum and Achromobacter. CONCLUSION The results showed that the bacteria from this study, belonging to genera Ochrobactrum and Achromobacter isolated from soil, harbor different β-lactamases encoding genes and can act as a reservoir of these genes.

Detection of bla PER on an IncA/C Plasmid in Stenotrophomonas maltophilia Isolated from Brazilian Soil

This study reports the presence of the blaPER, sul1 and sul2 genes and class 1 integron inside an IncA/C plasmid with ~ 30 Kb in an isolate of Stenotrophomonas maltophilia. PER-producing Stenotrophomonas maltophilia was obtained from a soil sample cultivated with corn in Maringá City, Paraná State, Brazil. To the best of our knowledge, this is the first report in the world of blaPER gene in a bacterium isolated from soil and in a Stenotrophomonas maltophilia.

A Fatal Bacteremia Caused by Hypermucousviscous KPC-2 Producing Extensively Drug-Resistant K64-ST11 Klebsiella pneumoniae in Brazil

We report a fatal bacteremia caused by Klebsiella pneumoniae in a 60–70-year-old patient from Brazil. The genomic analysis of three isolates (from blood culture, nasal and anal swabs) showed that the bacteremia was caused by a KPC-2 producing extensively drug-resistant K64-ST11 hypermucousviscous K. pneumoniae (hmKP) harboring several virulence and antimicrobial resistance genes. Although the isolates did not present virulence markers associated with hypervirulent K. pneumoniae (hvKP), they showed invasion and toxicity to epithelial Hep-2 cells; resistance to cell microbicidal mechanisms; and blood and human serum survival, evidencing their pathogenic potential. This study highlights the risk of infection caused by hmKp strains not characterized as hvKP as well as the clinical implications and difficulty of treatment, especially in elderly or immunocompromised patients.

Detection of virulence and β-lactamase encoding genes in Enterobacter aerogenes and Enterobacter cloacae clinical isolates from Brazil

Enterobacter cloacae and E. aerogenes have been increasingly reported as important opportunistic pathogens. In this study, a high prevalence of multi-drug resistant isolates from Brazil, harboring several β-lactamase encoding genes was found. Several virulence genes were observed in E. aerogenes, contrasting with the E. cloacae isolates which presented none.