Alberto Antonelli

First Detection of the mcr-1 Colistin Resistance Gene in Escherichia coli in Italy

Polymyxins are old antibiotics that have recently regained popularity for treatment of severe infections caused by extensively drug-resistant (XDR) Gram-negative bacterial strains ([1][1]). As a likely consequence, emergence of polymyxin resistance is being increasingly reported in the clinical

Breakthrough Lactobacillus rhamnosus GG bacteremia associated with probiotic use in an adult patient with severe active ulcerative colitis: case report and review of the literature

BackgroundProbiotics are widely investigated in the treatment of various bowel diseases. However, they may also have a pathogenic potential, and the role of Lactobacillus spp. as opportunistic pathogens, mostly following disruption of the intestinal mucosa, is emerging.Case reportWe report on a case of bacteremia caused by L. rhamnosus GG in an adult patient affected by severe active ulcerative colitis under treatment with corticosteroids and mesalazine. Lactobacillus bacteremia was associated with candidemia and occurred while the patient was receiving a probiotic formulation containing the same strain (as determined by PFGE typing), and was being concomitantly treated with i.v. vancomycin, to which the Lactobacillus strain was resistant. L. rhamnosus GG bacteremia, therefore, was apparently related with translocation of bacteria from the intestinal lumen to the blood.ConclusionsPending conclusive evidence, use of probiotics should be considered with caution in case of active severe inflammatory bowel diseases with mucosal disruption.

Intestinal carriage of Shewanella xiamenensis simulating carriage of OXA-48–producing Enterobacteriaceae

Positivity for bla(OXA-48)-like carbapenemase genes was revealed by molecular testing of a surveillance rectal swab from a patient who had previously been colonized and infected by an OXA-48-producing Klebsiella pneumoniae. Positivity was due to a coincidental carriage of Shewanella xiamenensis harboring a new bla(OXA-48)-like gene, while the K. pneumoniae was no longer present.

Performance of the BD MAX™ instrument with Check-Direct CPE real-time PCR for the detection of carbapenemase genes from rectal swabs, in a setting with endemic dissemination of carbapenemase-producing Enterobacteriaceae.

Carbapenemase-producing Enterobacteriaceae (CPE) represent an increasing public health issue and the early detection of colonization by CPE can help the implementation of infection control measures among inpatients. In this study, BD MAX Check-Direct CPE screen, with two different Master Mixes (BDMix and CPMix), using the automatic BD MAX(™) instrument, was evaluated for the detection of blaKPC, blaOXA-48, blaVIM and blaNDM genes, in comparison to selective broth enrichment and direct culture from rectal swabs. Among a total of 557 rectal swabs samples, 29 (5.2%) tested positive for CPE (23 for blaKPC, 5 for blaVIM and one for blaOXA-48). The sensitivity, specificity, positive and negative likelihood ratios values were 93.1%, 97.3%, 34.5 and 0.07, for BMix, and 100%, 97.1 %, 34.5 and 0 for CPMix, respectively. Five samples were positive with molecular methods only. The turn-around time was reduced from 18-24 hours (direct culture), or 48 h (broth enrichment) to only 3 h.

Lactobacillus Sepsis and Probiotic Therapy in Newborns: Two New Cases and Literature Review.

Many term and preterm infants are commonly supplemented with probiotics to prevent adverse effects of antibiotic administration and necrotizing enterocolitis and they are believed to be safe. However, the supplementation with Lactobacillus rhamnosus GG has been associated with the development of sepsis with a cause–effect relationship in six newborns and children. In this study, we report two further cases and discuss the emerging issue of probiotic supplementation safety in neonates. We conclude that physicians must be aware that supplementation with L. rhamnosus GG can cause sepsis in high-risk patients on rare occasions.

OXA-372, a novel carbapenem-hydrolysing class D β-lactamase from a Citrobacter freundii isolated from a hospital wastewater plant

OBJECTIVES The objective of this study was to characterize a novel class D carbapenemase, named OXA-372, identified in a carbapenem-resistant Citrobacter freundii strain (Cfr-FI-07) isolated from a hospital wastewater plant in central Italy. METHODS Cfr-FI-07 was isolated using a selective chromogenic medium for carbapenem-resistant Enterobacteriaceae. Carbapenemase production was confirmed by spectrophotometric assay. WGS was carried out using an Illumina MiSeq platform. The functional profile of OXA-372 was investigated by expression of the cloned gene in Escherichia coli and by analysis of kinetic parameters of the purified enzyme. RESULTS C. freundii Cfr-FI-07 produced carbapenemase activity, but tested negative for common carbapenemase genes. WGS confirmed the absence of known carbapenemase genes and revealed the presence of a novel class D β-lactamase (DBL) determinant, named blaOXA-372, encoding a protein distantly related to other DBLs. In E. coli, production of OXA-372 conferred resistance to penicillins, including temocillin, and reduced susceptibility to carbapenems, while susceptibility to expanded-spectrum cephalosporins was virtually unaffected. This substrate specificity was confirmed by kinetic characterization of the purified enzyme, which exhibited high catalytic efficiencies for carbapenems (kcat/KM values ≥ 0.22 s(-1) · μM(-1)). The blaOXA-372 gene was associated with a genetic platform of original structure consisting of a Tn402/Tn5053 hybrid transposon derivative, named Tn6255, inserted into a TnPa38-like transposon, named Tn6256, located on an IncA/C-IncN plasmid of approximately 140 kb. CONCLUSIONS OXA-372 is a novel class D carbapenemase, belonging to a new lineage of DBLs, encoded by a gene associated with mobile elements. Functional properties revealed similarities, but also some differences, compared with other class D carbapenemases.

Acquisition of plasmid-borne blaIMP-19 gene by a VIM-1-positive Pseudomonas aeruginosa of the sequence type 235 epidemic lineage

Sir, Acquired metallo-b-lactamases (MBLs) are the most common acquired carbapenemases in Pseudomonas aeruginosa. They confer a broad-spectrum b-lactam resistance profile, including resistance to the antipseudomonal penicillins, cephalosporins and carbapenems, that is not antagonized by the available b-lactamase inhibitors. Most MBL-producing strains exhibit a multidrug resistance profile, also including resistance to non-b-lactams, due to the accumulation of additional resistance determinants. Although several types of acquired MBLs have been detected in P. aeruginosa, the IMPand VIM-type enzymes are currently the most widespread. A number of genes encoding these enzymes (e.g. blaVIM-1, blaVIM-2, blaVIM-4 and blaIMP-1) have become associated with high-risk clones, such as clonal complex (CC) 235 and CC111, which has promoted their dissemination in Europe and other continents. IMP-19 is an IMP allelic variant that was originally detected in Enterobacter cloacae (GenBank/EMBL accession no. AB201264) and P. aeruginosa (GenBank/EMBL accession no. AB184976) from Japan and, subsequently, in an Aeromonas caviae isolated in France. More recently, it has been reported in Achromobacter xylosoxidans and Acinetobacter spp. isolates from Japan. Here, we report on the first detection of the blaIMP-19 gene in Italy, in a multidrug-resistant (MDR) P. aeruginosa clinical isolate that also produced VIM-1 and belonged to the CC235 epidemic lineage. Research letters

Characterization of a Novel Putative Xer-Dependent Integrative Mobile Element Carrying the blaNMC-A Carbapenemase Gene, Inserted into the Chromosome of Members of the Enterobacter cloacae Complex

ABSTRACT An Enterobacter ludwigii strain was isolated during routine screening of a Japanese patient for carriage of carbapenem-resistant Enterobacteriaceae. PCR analysis revealed the blaNMC-A carbapenemase gene. Whole-genome sequencing revealed that blaNMC-A was inserted in the chromosome and associated with a novel 29.1-kb putative Xer-dependent integrative mobile element, named EludIMEX-1. Bioinformatic analysis identified similar elements in the genomes of an Enterobacter asburiae strain and of other Enterobacter cloacae complex strains, confirming the mobile nature of this element.

Evolving beta-lactamase epidemiology in Enterobacteriaceae from Italian nationwide surveillance, October 2013: KPC-carbapenemase spreading among outpatients

Extended-spectrum beta-lactamases (ESBLs), AmpC-type beta-lactamases (ACBLs) and carbapenemases are among the most important resistance mechanisms in Enterobacteriaceae. This study investigated the presence of these resistance mechanisms in consecutive non-replicate isolates of Escherichia coli (n = 2,352), Klebsiella pneumoniae (n = 697), and Proteus mirabilis (n = 275) from an Italian nationwide cross-sectional survey carried out in October 2013. Overall, 15.3% of isolates were non-susceptible to extended-spectrum cephalosporins but susceptible to carbapenems (ESCR-carbaS), while 4.3% were also non-susceptible to carbapenems (ESCR-carbaR). ESCR-carbaS isolates were contributed by all three species, with higher proportions among isolates from inpatients (20.3%) but remarkable proportions also among those from outpatients (11.1%). Most ESCR-carbaS isolates were ESBL-positive (90.5%), and most of them were contributed by E. coli carrying blaCTX-M group 1 genes. Acquired ACBLs were less common and mostly detected in P. mirabilis. ESCR-carbaR isolates were mostly contributed by K. pneumoniae (25.1% and 7.7% among K. pneumoniae isolates from inpatients and outpatients, respectively), with blaKPC as the most common carbapenemase gene. Results showed an increasing trend for both ESBL and carbapenemase producers in comparison with previous Italian surveys, also among outpatients.

Travelers lowering their guard: a bacterial, viral and protozoan co-infection after a five-day journey in India.

We present a case of concurrent infections by Campylobacter jejuni, Giardia intestinalis and Hepatitis E virus acquired during a 5-days travel to India by an Italian traveller : Professionals responsible for pre- and post-travel care should underline food and water precautions and prescribe an adequate diagnostic work-up in symptomatic patients.