Emergence of vancomycin-resistant Enterococcus faecium in Sfax: clinical features and molecular typing

Selection and Characterization of Bacteriocinogenic Lactic Acid Bacteria from the Intestine of Gilthead Seabream (Sparus aurata) and Whiting Fish (Merlangius merlangus): Promising Strains for Aquaculture Probiotic and Food Bio-Preservation

This study sought to evaluate the probiotic properties and the food preservation ability of lactic acid bacteria isolates collected from the intestines of wild marine fishes (gilthead seabream (Sparus aurata) (n = 60) and whiting fish (Merlangius merlangus) (n = 40)) from the Mediterranean sea in the area of Mostaganem city, Algeria. Forty-two isolates were identified as: Enterococcus durans (n = 19), Enterococcus faecium (n = 15), Enterococcus faecalis (n = 4), Lactococcus lactis subp. lactis (n = 3), and Lactobacillus plantarum (n = 1). All isolates showed inhibition to at least one indicator strain, especially against Listeria monocytogenes, Staphylococcus aureus, Paenibacillus larvae, Vibrio alginolyticus, Enterococcus faecalis, Bacillus cereus, and Bacillus subtilis. In all collected isolates, PCR analysis of enterocin-encoding genes showed the following genes: entP (n = 21), ent1071A/B (n = 11), entB (n = 8), entL50A/B (n = 7), entAS48 (n = 5), and entX (n = 1). Interestingly, 15 isolates harbored more than one ent gene. Antimicrobial susceptibility, phenotypic virulence, and genes encoding virulence factors were investigated by PCR. Resistance to tetracycline (n = 8: tetL + tetK), erythromycin (n = 7: 5 ermA, 2 msrA, and 1 mef(A/E)), ciprofloxacin (n = 1), gentamicin (n = 1: aac(6')-aph(2″)), and linezolid (n = 1) were observed. Three isolates were gelatinase producers and eight were α-hemolytic. Three E. durans and one E. faecium harbored the hyl gene. Eight isolates showing safety properties (susceptible to clinically relevant antibiotics, free of genes encoding virulence factors) were tested to select probiotic candidates. They showed high tolerance to low pH and bile salt, hydrophobicity power, and co-culture ability. The eight isolates showed important phenotypic and genotypic traits enabling them to be promising probiotic candidates or food bio-conservers and starter cultures.

High-Resolution Genotyping Unveils Identical Ampicillin-Resistant Enterococcus faecium Strains in Different Sources and Countries: A One Health Approach

Multidrug-resistant (MDR) Enterococcus faecium (Efm) infections continue to increase worldwide, although epidemiological studies remain scarce in lower middle-income countries. We aimed to explore which strains circulate in E. faecium causing human infections in Tunisian healthcare institutions in order to compare them with strains from non-human sources of the same country and finally to position them within the global E. faecium epidemiology by genomic analysis. Antibiotic susceptibility testing was performed and transfer of vancomycin-vanA and ampicillin-pbp5 resistance was performed by conjugation. WGS-Illumina was performed on Tunisian strains, and these genomes were compared with Efm genomes from other regions present in the GenBank/NCBI database (n = 10,701 Efm genomes available May 2021). A comparison of phenotypes with those predicted by the recent ResFinder 4.1-CGE webtool unveiled a concordance of 88%, with discordant cases being discussed. cgMLST revealed three clusters [ST18/CT222 (n = 13), ST17/CT948 strains (n = 6), and ST203/CT184 (n = 3)], including isolates from clinical, healthy-human, retail meat, and/or environmental sources in different countries over large time spans (10–12 years). Isolates within each cluster showed similar antibiotic resistance, bacteriocin, and virulence genetic patterns. pbp5-AmpR was transferred by VanA-AmpR-ST80 (clinical) and AmpR-ST17-Efm (bovine meat). Identical chromosomal pbp5-platforms carrying metabolic/virulence genes were identified between ST17/ST18 strains of clinical, farm animal, and retail meat sources. The overall results emphasize the role of high-resolution genotyping as provided by WGS in depicting the dispersal of MDR-Efm strains carrying relevant adaptive traits across different hosts/regions and the need of a One Health task force to curtail their spread.

First molecular characterization of related cases of healthcare-associated infections involving multidrug-resistant Enterococcus faecium vanA in Algeria

Purpose

Vancomycin-resistant Enterococcus (VRE) faecium (VREfm) are highly resistant bacteria emerging worldwide and rarely studied using molecular tools in Algeria since their first report in 2006. The aim of the study was to investigate healthcare-associated infections (HAIs) involving the first VRE in Batna University Hospital, Algeria, and characterize isolates using molecular tools.

Patients and methods

Medical charts were reviewed for patients with VREfm. van genes were detected by multiplex polymerase chain reaction (PCR), and strains were characterized by automated repetitive sequence-based PCR (rep-PCR), multiplex rep-PCR, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST).

Results

During a 6-month period, VREfm infections occurred in four patients hospitalized in three wards. The four isolates were E. faecium vanA belonging to the hospital-adapted clonal complex 17. PCR-based methods did not discriminate the isolates but MLST and PFGE delineated a subgroup of three VREfm of identical pulsotype and sequence type (ST) 80 (yet identified for five isolates in the international PubMLST database) while the fourth isolate was of ST789 (not previously identified for a VREfm) and displayed an unrelated pulsotype. The three genotypically related isolates were recovered in patients who underwent surgery in the same department, suggesting an outbreak for which the source and route of transmission remained unidentified.

Conclusion

This first molecular epidemiology study of VRE in Algeria was useful in delimiting an outbreak involving three of the four HAI cases and revealed rarely encountered genotypes. Considering the threat and burden of VRE infections worldwide, particularly in the USA, and the late emergence in Algeria, our study supports the urgent need for improved and early adequate infection control measures to avoid VRE spread in North African hospitals.

Penicillin-Binding Protein 5 Sequence Alteration and Levels of plp5 mRNA Expression in Clinical Isolates of Enterococcus faecium with Different Levels of Ampicillin Resistance

Eighty-two nonduplicated ampicillin-resistant Enterococcus faecium (AREF) isolates from clinical infections at the Charles Nicolle Hospital of Tunisia were investigated. They were collected from January 2001 to December 2009. Genetic relationship between them was studied using pulsed-field gel electrophoresis. The amino acid sequence difference variations of the C-terminal part of penicillin-binding protein 5 (PBP5) versus levels of expressed mRNA were investigated by polymerase chain reaction (PCR), sequencing, and real-time PCR quantification of (PBP5), respectively. No β-lactamase activity was detected and none of our strains showed resistance to glycopeptides, which retain their therapeutic efficiency against enterococcal infections in our hospital. Pattern analysis of the strains revealed six main clones disseminating in different wards. Sequence data revealed the existence of 19 different plp5 alleles with a difference in 16 amino acid positions spanning from residue 414 to 632. Each allele presented at least five amino acid substitutions (His-470→Gln, Asn-496→Lys, Ala-499→Thr, Glu-525→Asp, and Glu-629→Val). No correlation between amino acid sequence polymorphism of PBP5 and levels of ampicillin resistance was detected. The levels of plp5 mRNA expression varied between strains and did not always correlate with levels of ampicillin resistance in clinical AREF.

Global spread of the hyl(Efm) colonization-virulence gene in megaplasmids of the Enterococcus faecium CC17 polyclonal subcluster

Enterococcus faecium has increasingly been reported as a nosocomial pathogen since the early 1990s, presumptively associated with the expansion of a human-associated Enterococcus faecium polyclonal subcluster known as clonal complex 17 (CC17) that has progressively acquired different antibiotic resistance (ampicillin and vancomycin) and virulence (esp(Efm), hyl(Efm), and fms) traits. We analyzed the presence and the location of a putative glycoside hydrolase hyl(Efm) gene among E. faecium strains obtained from hospitalized patients (255 patients; outbreak, bacteremic, and/or disseminated isolates from 23 countries and five continents; 1986 to 2009) and from nonclinical origins (isolates obtained from healthy humans [25 isolates], poultry [30], swine [90], and the environment [55]; 1999 to 2007). Clonal relatedness was established by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Plasmid analysis included determination of content and size (S1-PFGE), transferability (filter mating), screening of Rep initiator proteins (PCR), and location of vanA, vanB, ermB, and hyl(Efm) genes (S1/I-CeuI hybridization). Most E. faecium isolates contained large plasmids (>150 kb) and showed variable contents of van, hyl(Efm), or esp(Efm). The hyl(Efm) gene was associated with megaplasmids (170 to 375 kb) of worldwide spread (ST16, ST17, and ST18) or locally predominant (ST192, ST203, ST280, and ST412) ampicillin-resistant CC17 clones collected in the five continents since the early 1990s. All but one hyl(Efm)-positive isolate belonged to the CC17 polyclonal subcluster. The presence of hyl(Efm) megaplasmids among CC17 from Europe, Australia, Asia, and Africa since at least the mid-1990s was documented. This study further demonstrates the pandemic expansion of particular CC17 clones before acquisition of vancomycin resistance and putative virulence traits and describes the presence of megaplasmids in most of the contemporary E. faecium isolates with different origins.