João Pires

Travelers Can Import Colistin-Resistant Enterobacteriaceae, Including Those Possessing the Plasmid-Mediated mcr-1 Gene

ABSTRACT Stool samples from 38 travelers returning from India were screened for extended-spectrum cephalosporin- and carbapenem-resistant Enterobacteriaceae implementing standard selective plates. Twenty-six (76.3%) people were colonized with CTX-M or DHA producers, but none of the strains was colistin resistant and/or mcr-1 positive. Nevertheless, using overnight enrichment and CHROMagar Orientation plates supplemented with colistin, four people (10.5%) were found to be colonized with colistin-resistant Escherichia coli. One cephalosporin-susceptible sequence type 10 (ST10) strain carried a 4,211-bp ISApl1-mcr-1-ISApl1 element in an IncHI2 plasmid backbone.

Characterization of Globally Spread Escherichia coli ST131 Isolates (1991 to 2010)

ABSTRACT The characterization of a broad representative sample of ST131 Escherichia coli isolates from different origins and settings (1991 to 2010) revealed that this clonal group has likely diversified recently and that the expansion of particular variants has probably been favored by the capture of diverse, multidrug-resistant IncFII plasmids (pC15-1a, pEK499, pKF3-140-like). The low ability to adhere and to grow as biofilm that was detected in this study suggests unknown mechanisms for the persistence of this clonal group which need to be further explored.

In Vitro Activity of the Novel Antimicrobial Peptide Dendrimer G3KL against Multidrug-Resistant Acinetobacter baumannii and Pseudomonas aeruginosa

ABSTRACT The in vitro activity of the novel antimicrobial peptide dendrimer G3KL was evaluated against 32 Acinetobacter baumannii (including 10 OXA-23, 7 OXA-24, and 11 OXA-58 carbapenemase producers) and 35 Pseudomonas aeruginosa (including 18 VIM and 3 IMP carbapenemase producers) strains and compared to the activities of standard antibiotics. Overall, both species collections showed MIC50/90 values of 8/8 μg/ml and minimum bactericidal concentrations at which 50% or 90% of strains tested are killed (MBC50/90) of 8/8 μg/ml. G3KL is a promising molecule with antibacterial activity against multidrug-resistant and extensively drug-resistant A. baumannii and P. aeruginosa isolates.

Diversity and biofilm-production ability among isolates of Escherichia coli phylogroup D belonging to ST69, ST393 and ST405 clonal groups

BackgroundPhylogenetic group D Escherichia coli clones (ST69, ST393, ST405) are increasingly reported as multidrug resistant strains causing extra-intestinal infections. We aim to characterize inter- and intraclonal diversity of a broad sample (isolates from different geographic locations and origins with variable antibiotic resistance profiles, 1980-2010) and their ability to adhere and form biofilm by both a modified quantitative biofilm producing assay and Field Emission Scanning Electron Microscopy (FESEM).ResultsHigh virulence scores were observed among ST69 (median 14/range 9–15) and ST393 (median 14/range 8–15) clones, particularly enriched in pap alleles, iha, kpsMTII-K5 and ompT, in contrast with ST405 (median 6/range 2–14) isolates, exhibiting frequently fyuA, malX and traT. All ST69 and ST393 and only two ST405 isolates were classified as ExPEC. Biofilm production was detected in two non-clinical ST69 and three ST393 isolates from different origins showing variable virulence profiles. Within each clonal group, and despite the high diversity of PFGE-types observed, isolates from different countries and recovered over large periods of time were clustered in a few groups sharing common virulence gene profiles among ST69 (n = 10 isolates) and ST393 (n = 9 isolates) (fimH-iha-iutA-kpsMTII-K5-(traT)-sat-(ompT)-papA-papEF-papGII-papC) or ST405 (n = 6 isolates) (fimH-traT-fyuA-malX).ConclusionsThis study highlights the circulation of highly transmissible ST69, ST393 and ST405 variants among different settings. Biofilm production seems not to be directly correlated with their epidemiological success.

Evaluation of the recently launched Rapid CARB Blue kit for detection of carbapenemase-producing Gram negative bacteria

The detection of carbapenemase-producing bacteria is still a challenge for many laboratories worldwide, especially in low-income countries, though critical from a clinical or epidemiological point of view ([1][1]). The Blue-Carba test is an inexpensive biochemical method for the detection of

Heterogeneous Genetic Location of mcr-1 in Colistin-Resistant Escherichia coli Isolates from Humans and Retail Chicken Meat in Switzerland: Emergence of mcr-1-Carrying IncK2 Plasmids

ABSTRACT We characterized the genetic environment of mcr-1 in colistin-resistant Escherichia coli strains isolated in Switzerland during 2014 to 2016 from humans (n = 3) and chicken meat (n = 6). Whole-genome and plasmid sequencing identified the mcr-1 gene integrated in IncX4 (of which, one strain carried the mcr-1.2 variant), IncI2, IncHI2, and novel IncK2 plasmids (overall, n = 7), as well as in the bacterial chromosome (n = 2) in single or duplicate copies. Our study supports the easy mobilization of mcr-1 across diverse genetic locations.

Polyclonal Intestinal Colonization with Extended-Spectrum Cephalosporin-Resistant Enterobacteriaceae upon Traveling to India.

We aimed to assess the intestinal colonization dynamics by multiple extended-spectrum cephalosporin-resistant Enterobacteriaceae (ESC-R-Ent) clones in Swiss travelers to India, a country with high prevalence of these multidrug-resistant pathogens. Fifteen healthy volunteers (HVs) colonized with ESC-R-Ent after traveling to India who provided stools before, after, and at 3- and 6-month follow-up are presented in this study. Stools were enriched in a LB broth containing 3 mg/L cefuroxime and plated in standard selective media (BLSE, ChromID ESBL, Supercarba) to detect carbapenem- and/or ESC-R-Ent. At least 5 Enterobacteriaceae colonies were analyzed for each stool provided. All strains underwent phenotypic tests (MICs in microdilution) and molecular typing to define bla genes (microarray, PCR/sequencing), clonality (MLST, rep-PCR), and plasmid content. While only three HVs were colonized before the trip, all participants had positive stools after returning, but the colonization rate decreased during the follow-up period (i.e., six HVs were still colonized at both 3 and 6 months). More importantly, polyclonal acquisition (median of 2 clones, range 1–5) was identified at return in all HVs. The majority of the Escherichia coli isolates belonged to phylogenetic groups A and B1 and to high diverse non-epidemic sequence types (STs); however, 15% of them belonged to clonal complex 10 and mainly possessed blaCTX−M−15 genes. F family plasmids were constantly found (~80%) in the recovered ESC-R-Ent. Our results indicate a possible polyclonal acquisition of the ESC-R-Ent via food-chain and/or through an environmental exposure. For some HVs, prolonged colonization in the follow-up period was observed due to clonal persistence or presence of the same plasmid replicon types in a new bacterial host. Travel medicine practitioners, clinicians, and clinical microbiologists who are facing the returning travelers and their samples for different reasons should be aware of this important phenomenon, so that better infection control measures, treatment strategies, and diagnostic tests can be adopted.

Double Copies of blaKPC-3::Tn4401a on an IncX3 Plasmid in Klebsiella pneumoniae Successful Clone ST512 from Italy

ABSTRACT A carbapenem-resistant sequence type 512 (ST512) Klebsiella pneumoniae carbapenemase 3 (KPC-3)-producing K. pneumoniae strain showing a novel variant plasmid content was isolated in Palermo, Italy, in 2014. ST512 is a worldwide successful clone associated with the spread of blaKPC genes located on the IncFIIk pKpQIL plasmid. In our ST512 strain, the blaKPC-3 gene was unusually located on an IncX3 plasmid, whose complete sequence was determined. Two copies of blaKPC-3::Tn4401a caused by intramolecular transposition events were detected in the plasmid.

Increase of widespread A, B1 and D Escherichia coli clones producing a high diversity of CTX-M-types in a Portuguese hospital.

AIM To characterize temporal shifts in extended-spectrum β-lactamases (ESBLs) and clones of clinical Escherichia coli isolates. MATERIALS & METHODS All ESBL-producing E. coli isolates from a Portuguese hospital (n = 112; June 2006-June 2007 and January-December 2010) were characterized by identification of phylogenetic groups, ESBL-types and virulence genes, XbaI-PFGE and MLST. RESULTS We observed a substantial increase in widespread E. coli clones from phylogroups A, B1 and D (e.g., ST10, ST23, ST117, ST155, ST648) producing mainly CTX-M-1, -14, -32 or SHV-12, along with a decrease in the proportion of the predominant CTX-M-15-producing B2-ST131 clone. CONCLUSION The amplification of diverse CTX-M-producing A, B1 and D clonal complexes, which have been long identified in Portuguese nonclinical settings, unveils a role for these reservoirs in the landscape of ESBL-producing E. coli in the clinical setting.

Prevalence of extended-spectrum β-lactamase-producing Enterobacteriaceae and Methicillin-Resistant Staphylococcus aureus in pig farms in Switzerland.

The presence of Methicillin-Resistant Staphylococcus aureus (MRSA) in pig farms has been widely reported, and the emergence of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) has been documented in several countries. However, data for Switzerland are very scarce. This study aimed to compare changes in the prevalence of MRSA in Swiss pig farms between 2008 and 2015 and make the first ever estimates of the presence of ESBL-E and carbapenemase producers in pigs and pig farm workers. Results showed that ESBL-E was present in both pigs and farm workers and that the proportion of farms with MRSA had increased fourfold in seven years (from 7% to 31%). Associations between antibiotic use and resistant bacteria carriage were shown.