Biology subjects

Bonnin, R.

Publications and source records attributed to Bonnin, R..

5 recordsLinked to original sources

bioRxiv2023

Emergence of Acinetobacter baumannii International Clone 10 predominantly found in the Middle East

Acinetobacter baumannii is a globally distributed human pathogen. Infections caused by carbapenem-resistant isolates of A. baumannii (CRAB) are of great concern, as treatment options are very limited. Despite having among the highest rates reported worldwide, there exists limited genomic data from CRAB strains isolated in the Middle East. Here we report epidemiological, phenotypic, and genome sequencing data (short reads and long reads) on a set of 60 A. baumannii isolates belonging to Sequence Type ST158 (Pasteur MLST scheme). They represent a novel international clone (IC), designated IC10, with limited geographic spread beyond the Middle East. Specific antibiotic-resistance genes associated with this clone were identified and data on the plasmid content associated with this lineage are presented.

microbiology↗

bioRxiv2022

Phage-plasmids spread antibiotic resistance genes through infection and lysogenic conversion

Antibiotic resistance is rapidly spreading by horizontal transfer of resistance genes in mobile genetic elements. While plasmids are key drivers of this process, very few integrative phages encode antibiotic resistance genes. Here, we find that phage-plasmids, elements that are both phages and plasmids, often carry antibiotic resistance genes. We found 60 phage-plasmids with 184 antibiotic resistance genes, including broad-spectrum-cephalosporins, carbapenems, aminoglycosides, fluoroquinolones and colistin. These genes are in a few hotspots, seem to have been co-translocated with transposable elements, and are often in class I integrons, which had not been previously found in phages. We tried to induce six phage-plasmids with resistance genes (including four with resistance integrons) and succeeded in five cases. Other phage-plasmids and integrative prophages were co-induced in these experiments. As a proof of principle, we focused on a P1-like element encoding an extended spectrum {beta}-lactamase, blaCTX-M-55. After induction, we confirmed that its capable to infect and convert four other E. coli strains. Its re-induction led to further conversion of a sensitive strain, confirming its a fully functional phage. This study shows that phage-plasmids carry a large diversity of clinically relevant antibiotic resistance genes that they transfer across bacteria. As plasmids, these elements seem very plastic and capable of acquiring genes from other plasmids. As phages, they may provide novel paths of transfer for resistance genes, because they can infect bacteria distant in time and space from the original host. As a matter of alarm, they may also eventually mediate transfer to other types of phages. ImportanceDissemination of antimicrobial resistances is a major threat to global health. Here, we show that a group of temperate bacterial viruses (=phages), termed phage-plasmids, commonly encode different and multiple types of resistance genes of high clinical importance, often in integrons. This is unexpected since phages typically do not carry resistance genes and, hence, do not confer their hosts with resistance upon infection and genome integration. Our experiments with phage-plasmids isolated from clinical settings confirmed they infect sensitive strains, rendering them antibiotic resistant. The spread of antibiotic resistance genes by phage-plasmids is worrisome because it dispenses cell-to-cell contact, necessary for the canonical plasmid transfer (=conjugation). Furthermore, their integrons are now genetic platforms for the acquisition of novel resistance genes.

microbiology↗

bioRxiv2022

Carbapenem heteroresistance of KPC-producing Klebsiella pneumoniae results from tolerance, persistence and resistance.

Carbapenemase-producing Klebsiella pneumoniae (CPKp) have disseminated globally and represent a major threat in hospitals with few therapeutic options and high mortality rates. Isolates producing the carbapenemase KPC (KPC-Kp) might be classified as susceptible according to clinical breakpoints by antibiotic susceptibility testing (AST), allowing the use of imipenem or meropenem for treatment of infections. However, some KPC-Kp show heteroresistance (HR) to carbapenems, with colonies growing in the inhibition halo of agar-based AST. HR KPC-Kp have been associated with a higher risk of treatment failure. Here, we characterized the diversity of mechanisms behind HR to imipenem of these isolates. By analyzing a diverse collection of CPKp, we showed that HR is frequent among KPC-Kp. By monitoring single HR colony appearance using the ScanLag setup, we discriminated surviving cells in two subpopulations leading to a Gaussian-like distribution of early-appearing colonies, with a delayed emergence compared to colonies arising in the absence of antibiotics, and a long tail of late-appearing colonies. A subset of colonies showed a reduced growth rate. Characterization of surviving populations by AST and whole-genome sequencing of 333 colonies revealed a majority of parental genotypes and a broad landscape of genetic alterations in 28% of the colonies, including gene loss, DNA amplification and point mutations. This unveils the complexity of imipenem HR among KPC-Kp isolates, which involves tolerant and persistent cells, but also resistant bacteria. These observations contribute to a better understanding of reasons behind carbapenem treatment failure of KPC-Kp isolates. IMPORTANCEThe ability of a bacterium to defeat antibiotics not only depends upon resistance, but also on tolerance and persistence, which allow a bacterial population to temporarily survive high drug doses. Carbapenems are antibiotics of last resort and Klebsiella pneumoniae isolates producing the carbapenemase KPC are a threat to hospitals, although they might remain susceptible to carbapenems. However, seemingly homogeneous populations of KPC-K. pneumoniae isolates frequently show varying degrees of susceptibility to carbapenem, i.e., a phenomenon called heteroresistance. We characterized bacteria surviving a high dose of imipenem, progressively degraded by the released carbapenemase, by monitoring the growth of the resulting colonies using the ScanLag system, their genome sequence and carbapenem susceptibility. We show that the observed phenotypic diversity combines tolerance, persistence and resistance making the treatment with high doses of carbapenems frequently inefficient.

microbiology↗

bioRxiv2021

Specificities and commonalities of carbapenemase producing Escherichia coli isolated in France from 2012 to 2015.

Carbapenemase-producing Escherichia coli (CP-Ec) represent a major public health threat with a risk of dissemination in the community as it has occurred for lineages producing extended spectrum {beta}-lactamases. To characterize the extend of CP-Ec spread in France, isolates from screening and infection samples received at the French National Reference Centre laboratory (F-NRC) for carbapenemase-producing Enterobacterales were investigated. Six hundred and ninety one CP-Ec isolates collected between 2012 and 2015 and 22 before were fully sequenced. Analysis of their genome sequences revealed some disseminating multidrug resistant (MDR) lineages frequently acquiring diverse carbapenemase genes mainly belonging to clonal complex (CC) 23 (ST 410) and CC10 (ST10, ST167) and sporadic isolates including rare ST131 isolates (n=17). However, the most represented ST was ST38 (n=92) with four disseminated lineages carrying blaOXA-48-like genes inserted in the chromosome. Globally, the most frequent carbapenemase gene (n=457) was blaOXA-48. It was also less frequently associated with MDR isolates being the only resistance gene in 119 isolates. Thus, outside the ST38 clades, its acquisition was frequently sporadic with no sign of dissemination, reflecting the circulation of the IncL plasmid pOXA-48 in France and its high frequency of conjugation. In contrast blaOXA-181 or blaNDM genes were often associated with the evolution of MDR E. coli lineages characterized by mutations in ftsI and ompC. IMPORTANCECarbapenemase-producing Escherichia coli (CP-Ec) might be difficult to detect, as minimal inhibitory concentrations can be very low. However, their absolute number and their proportion among carbapenem-resistant Enterobacterales have been increasing, as reported by WHO and national surveillance programs. This suggests a still largely uncharacterized community spread of these isolates. Here we have characterized the diversity and evolution of CP-Ec isolated in France before 2016. We show that carbapenemase genes are associated with a wide variety of E. coli genomic backgrounds and a small number of dominant phylogenetic lineages. In a significant proportion of CP-Ec, the most frequent carbapenemase gene blaOXA-48, was detected in isolates lacking any other resistance gene, reflecting the dissemination of pOXA-48 plasmids, likely in the absence of any antibiotic pressure. In contrast carbapenemase gene transfer may also occur in multi-drug resistant E. coli, ultimately giving rise to at-risk lineages encoding carbapenemases with a high potential of dissemination.

microbiology↗

bioRxiv2019

Fast and robust detection of colistin resistance in Escherichia coli using the MALDI Biotyper Sirius mass spectrometry system

Polymyxin antibiotics are a last-line treatment for multidrug-resistant Gram-negative bacteria. However, the emergence of colistin resistance, including the spread of mobile mcr genes, necessitates the development of improved diagnostics for the detection of colistin-resistant organisms in hospital settings. The recently developed MALDIxin test enables detection of colistin resistance by MALDI-TOF mass spectrometry in less than 15 minutes but is not optimized for the mass spectrometers commonly found in clinical microbiology laboratories. In this study, we adapted the MALDIxin test for the MALDI Biotyper Sirius MALDI-TOF mass spectrometry system (Bruker Daltonics). We optimized the sample preparation protocol using a set of 6 MCR-expressing Escherichia coli clones and validated the assay with a collection of 40 E. coli clinical isolates, including 19 MCR producers, 12 chromosomally-resistant isolates and 9 polymyxin-susceptible isolates. We calculated Polymyxin resistance ratio (PRR) values from the acquired spectra; a PRR value of zero, indicating polymyxin susceptibility, was obtained for all colistin-susceptible E. coli isolates, whereas positive PRR values, indicating resistance to polymyxins, were obtained for all resistant strains independent of the genetic basis of resistance. Thus, we report a preliminary feasibility study showing that an optimized version of the MALDIxin test, adapted for the routine MALDI Biotyper Sirius, provides an unbiased, fast, reliable, cost-effective and high-throughput way of detecting colistin resistance in clinical E. coli isolates.

microbiology↗