Selection of KPC-2-producing Providencia stuartii during treatment for septicemia

fosA11, a novel chromosomal-encoded fosfomycin resistance gene identified in Providencia rettgeri

This study investigated resistance genes corresponding to the fosfomycin resistance phenotype in clinical isolate Providencia rettgeri W986, as well as characterizing the enzymatic activity of FosA11 and the genetic environment. Antimicrobial susceptibility testing was performed using the agar microdilution method based on the Clinical and Laboratory Standards Institute guidelines. The whole genomic sequence of Providencia rettgeri W986 was obtained using Illumina sequencing and the PacBio platform. The fosA-11 gene was amplified by PCR and cloned into the pUCP20 vector. The recombinant strain pCold1-fosA11-BL21 was expressed to extract the target protein, and absorbance photometry was applied for enzymatic parameter determination. Minimal inhibitory concentration (MIC) tests showed that W986 conferred fosfomycin resistance and was inhibited by phosphonoformate, thereby indicating the presence of a FosA protein. A novel resistance gene designated as fosA11 was identified by whole-genome sequencing and bioinformatics analysis, and it shared 54.41%-64.23% amino acid identity with known FosA proteins. Cloning fosA11 into Escherichia coli obtained a significant increase (32-fold) in the MIC with fosfomycin. Determination of the enzyme kinetics showed that FosA11 had a high catalytic effect on fosfomycin, with Km = 18 ± 4 and Kcat = 56.1 ± 3.2. We also found that fosA11 was located on the chromosome, but the difference in the GC content between the chromosome and fosA11 was dubious, and thus further investigation is required. In this study, we identified and characterized a novel fosfomycin inactivation enzyme called FosA11. The origin and prevalence of the fosA11 gene in other bacteria require further investigation.IMPORTANCEFosfomycin is an effective antimicrobial agent against Enterobacterales strains. However, the resistance rate of fosfomycin is increasing year by year. Therefore, it is necessary to study the deep molecular mechanism of bacterial resistance to fosfomycin. We identified a novel chromosomal fosfomycin glutathione S-transferase, FosA11 from Providencia rettgeri, which shares a very low identity (54.41%-64.23%) with the previously known FosA and exhibits highly efficient catalytic ability against fosfomycin. Analysis of the genetic context and origin of fosA11 displays that the gene and its surrounding environments are widely conserved in Providencia and no mobile elements are discovered, implying that FosA11 may be broadly important in the natural resistance to fosfomycin of Providencia species.

Epidemiology and characterization of Providencia stuartii isolated from hospitalized patients in southern Brazil: a possible emerging pathogen

This study aimed to characterize the virulence factors and antimicrobial resistance of Providencia stuartii , an opportunistic pathogen that causes human infections. We examined 45 isolates of P. stuartii both genotypically and phenotypically by studying their adherence to HeLa cells, biofilm formation, cytotoxicity and antimicrobial resistance, and analysed their genomes for putative virulence and resistance genes. This study found that most isolates possessed multiple virulence genes, including fimA, mrkA, fptA, iutA, ireA and hlyA, and were cytotoxic to Vero cells. All the isolates were resistant to amoxicillin plus clavulanic acid, levofloxacin and sulfamethoxazole plus trimethoprim, and most were resistant to ceftriaxone and cefepime. All isolates harboured extended-spectrum beta-lactamase coding genes such as bla CTX-M-2 and 23/45(51.11 %) of them also harboured bla CTX-M-9. The gene KPC-2 (carbapenemase) was detected in 8/45(17.77 %) isolates. This study also found clonality among the isolates, indicating the possible spread of the pathogen among patients at the hospital. These results have significant clinical and epidemiological implications and emphasize the importance of a continued understanding of the virulence and antimicrobial resistance of this pathogen for the prevention and treatment of future infections.

Investigation of factors related to biofilm formation in Providencia stuartii

Providencia stuartii is one of the Enterobacteriaceae species of medical importance commonly associated with urinary infections, which can also cause other ones, including uncommon ones, such as liver abscess and septic vasculitis. This bacterium stands out in the expression of intrinsic and acquired resistance to antimicrobials. Besides, it uses mechanisms such as biofilm for its persistence in biotic and abiotic environments. This study investigated the cellular hydrophobicity profile of clinical isolates of P. stuartii. It also analyzed genes related to the fimbrial adhesin in this species comparing with other reports described for other bacteria from Enterobacteriaceae family. The investigated isolates to form biofilm and had a practically hydrophilic cell surface profile. However, fimH and mrkD genes were not found in P. stuartii, unlike observed in other species of Enterobacteriaceae. These results show that P. stuartii has specificities regarding its potential for biofilm formation, which makes it difficult to destabilize the infectious process and increases the permanence of this pathogen in hospital units.

First report of the aac(6')-Ib-cr gene in Providencia stuartii isolates in Brazil

INTRODUCTION

The aac(6')-Ib-cr and bla KPC genes are spreading among Enterobacteriaceae species, including Providencia stuartii, in some countries of world.

METHODS

These genes were investigated in 28 P. stuartii isolates from a public hospital in Recife, Pernambuco, Brazil, by PCR and sequencing.

RESULTS

The aac(6')-Ib-cr gene was detected in 16 resistant isolates, and the bla KPC gene was seen in 14.

CONCLUSIONS

The presence of these genes in P. stuartii multi- and extensively drug-resistant isolates indicates that the resistance arsenal of this species is increasing, thus limiting the therapeutic options.

Genomic Analysis of two NDM-1 Providencia stuartii Strains Recovered from a Single Patient

In the last years, an increasing number of untreatable infections caused by drug-resistant microbes have impacted the health care system. Worldwide, infections caused by carbapenem-resistant (CR) Gram-negative bacilli have dramatically increased. Among the CR-Gram-negative bacilli, those producing carbapenemases, such as NDM-1, are the main concern. Different Enterobacterales harboring NDM-1 have been reported lately. Providencia stuartii, a member of the Morganellaceae family, is ubiquitous in the environment, but is also known to cause nosocomial infections. Here we describe the genomic analysis of two NDM-1- producing P. stuartii strains recovered from the same patient as well as other carbapenem resistant strains recovered from the same hospital. As a result of the genomic analysis thirteen resistance genes, including three to β-lactams (bla_OXA-1, bla_TEM-1, bla_NDM-1), four to aminoglycosides (aphA6, aac(3)-IId, aac(2')-Ia, aac(6')-Ib-cr5), one to sulfonamides (sul1), two to chloramphenicol (catB3, catA3), one to rifampicin, one to bleomycin (ble), and one to tetracycline (tet(B)) were found. Moreover, a variety of mobile genetic elements, such as insertion sequences, plasmids and phage- related sequences, were found within P. stuartii genomes. The spread of carbapenem-resistant isolates remains a significant clinical and public health concern. Therefore, we considered that the detection of CR isolates is an essential step in addressing this problem.

First literature review of carbapenem-resistant Providencia

Providencia species are Gram-negative bacteria that belong to the Enterobacteriaceae family. They have intrinsic resistance to colistin and tigecycline, which makes treatment of the multidrug-resistant strains of Providencia challenging. Carbapenem-resistant Providencia species are increasingly reported. In this review, patients' characteristics, resistance mechanisms, treatment and infection control measures of carbapenem-resistant Providencia species in the literature are described.

Antimicrobial resistance in Enterobacteriaceae in Brazil: focus on β-lactams and polymyxins

During the last 30 years there has been a dissemination of plasmid-mediated β-lactamases in Enterobacteriaceae in Brazil. Extended spectrum β-lactamases (ESBL) are widely disseminated in the hospital setting and are detected in a lower frequency in the community setting. Cefotaximases are the most frequently detected ESBL type and Klebsiella pneumoniae is the predominant species among ESBL producers. Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae became widely disseminated in Brazil during the last decade and KPC production is currently the most frequent resistance mechanism (96.2%) in carbapenem resistant K. pneumoniae. To date KPC-2 is the only variant reported in Brazil. Polymyxin B resistance in KPC-2-producing K. pneumoniae has come to an alarming rate of 27.1% in 2015 in São Paulo, the largest city in Brazil. New Delhi metallo-β-lactamase was detected in Brazil in 2013, has been reported in different Brazilian states but are not widely disseminated. Antimicrobial resistance in Enterobacteriaceae in Brazil is a very serious problem that needs urgent actions which includes both more strict adherence to infection control measures and more judicious use of antimicrobials.