Laurent Dortet

Emergence of Streptococcus pneumoniae of serotype 19A in France: molecular capsular serotyping, antimicrobial susceptibilities, and epidemiology

We have studied 457 Streptococcus pneumoniae isolated in 2007 from adults and children. For all isolates, both latex agglutination and molecular capsular typing were performed. Antibiotic resistance patterns were determined. S. pneumoniae 19A was the most frequently isolated serotype (34.7%) both in children and adults. It represented 12.8% of the strains isolated from invasive infections in adults and 27.0% in children and 63.6% (110/173) of strains isolated from acute otitis media. Between children and adults, no difference concerning antibiotic susceptibility was observed for penicillin, amoxicillin, cefotaxime, and erythromycin in strains isolated from invasive diseases. Comparing antibiotic susceptibilities according to the serotype, the 19A isolates appeared to be the least susceptible to penicillin (3.2%) and erythromycin (4.5%), followed by serotypes 19F and 14. We confirm the predominance of serotype 19A among S. pneumoniae responsible for invasive and noninvasive diseases either in children or adults in France.

National survey of colistin resistance among carbapenemase-producing Enterobacteriaceae and outbreak caused by colistin-resistant OXA-48-producing Klebsiella pneumoniae , France, 2014

From January 2014 to December 2014, 972 consecutive non-replicate carbapenemase-producing Enterobacteriaceae isolates from colonised or infected patients were collected at the Associated French National Reference Centre as part of the French national survey on antimicrobial resistance. It included 577 Klebsiella spp. (59%), 236 Escherichia coli (24%), 108 Enterobacter spp. (11%), 50 Citrobacter spp. (5%), and a single Salmonella spp. isolate (0.1%). Of 561 K. pneumoniae isolates, 35 were found to be resistant to colistin (6.2%). PFGE analysis revealed a clonal outbreak involving 15 K. pneumoniae isolates belonging to sequence type ST11, recovered in a single hospital in the Picardie region in northern France. Those clonally related isolates showed variable levels of resistance to colistin, ranging from 4 to 64 mg/L. They harboured the blaOXA-48 carbapenemase gene and the blaCTX-M-15 extended-spectrum beta-lactamase gene. Among the 91 Enterobacter cloacae isolates, seven were resistant to colistin and produced different types of carbapenemases. Surprisingly, none of the E. coli and Citrobacter spp. isolates showed resistance to colistin. This national survey including carbapenemase-producing isolates recovered in 2014 reported a high rate of colistin resistance in K. pneumoniae and E. cloacae (6.2% and 7.7%, respectively) in France.

Genetic and biochemical characterization of FRI-1, a carbapenem-hydrolyzing class A β-Lactamase from Enterobacter cloacae

ABSTRACT An Enterobacter cloacae isolate was recovered from a rectal swab from a patient hospitalized in France with previous travel to Switzerland. It was resistant to penicillins, narrow- and broad-spectrum cephalosporins, aztreonam, and carbapenems but remained susceptible to expanded-spectrum cephalosporins. Whereas PCR-based identification of the most common carbapenemase genes failed, the biochemical Carba NP test II identified an Ambler class A carbapenemase. Cloning experiments followed by sequencing identified a gene encoding a totally novel class A carbapenemase, FRI-1, sharing 51 to 55% amino acid sequence identity with the closest carbapenemase sequences. However, it shared conserved residues as a source of carbapenemase activity. Purified β-lactamase FRI-1 hydrolyzed penicillins, aztreonam, and carbapenems but spared expanded-spectrum cephalosporins. The 50% inhibitory concentrations (IC50s) of clavulanic acid and tazobactam were 10-fold higher than those found for Klebsiella pneumoniae carbapenemase (KPC), IMI, and SME, leading to lower sensitivity of FRI-1 activity to β-lactamase inhibitors. The blaFRI-1 gene was located on a ca. 110-kb untypeable, transferable, and non-self-conjugative plasmid. A putative LysR family regulator-encoding gene at the 5′ end of the β-lactamase gene was identified, leading to inducible expression of the blaFRI-1 gene.

Multiple colonization with highly resistant bacteria: carbapenemase-producing Enterobacteriaceae, carbapenemase-producing Pseudomonas aeruginosa, carbapenemase-producing Acinetobacter baumannii, and glycopeptide-resistant Enterococcus faecium

The dissemination of carbapenemase-producing bacteria worldwide is an important source of concern because carbapenemase producers are multidrug resistant (Nordmann and Poirel, 2014). National guidelines increasingly recommend a systematic screening of at least carbapenemase-producing Enterobacteriaceae (CPE) and glycopeptideresistant enterococci (GRE) in patients admitted to hospitals who have been hospitalized aboard during the preceding 12 months (Lepelletier et al., 2011).We have investigated the occurrence of colonization and infection with multiple highly resistant bacteria of more than 4 different genus in 2 patients directly transferred from a foreign country. In June 2014, a 33-year-old Frenchman (patient A)was admitted for a suicide attempt in a Vietnamese hospital where he was treated during 10 days for pneumonia with piperacillin + tazobactam before his transfer to Necker-Enfants Malades University Hospital in Paris, France. At the day of his hospitalization in France, distal protected pulmonary samples were collected, and imipenem was administered subsequently to a persistent fever. In addition, systematic screening to detect carbapenemase producers and GRE was also performed. Screening of extended spectrum β-lactamase (ESBL) producing Enterobacteriaceae, carbapenemase producers, and GRE was done on selective media (bioMérieux, La Balme-les-Grottes, France) ChromID ESBL, ChromID Carba Smart, and VRE medium, respectively. Carbapenemase production was identified using the Carba NP test for Enterobacteriaceae (Dortet et al., 2014a) and Pseudomonas aeruginosa (Dortet et al., 2012) and CarbAcineto NP test for Acinetobacter baumannii (Dortet et al., 2014b). Definitive identifications of resistance determinant were done by PCR amplifications followed by sequencing. Pulmonary samples grew an OXA-23–producing A. baumannii isolate and an IMP-1–producing P. aeruginosa (Table 1). Screening identified also that the patient was colonized with a KPC-2–producing Klebsiella pneumoniae, a CTX-M-15– producing K. pneumoniae, and a VanA-positive glycopeptide-resistant Enterococcus faecium (Table 1). Patient B was a 66-year-old French womanwhowas hospitalized in May 2014 in the intensive care unit of Paris suburb (Saint-Denis, France). She was directly transferred from Morocco, where she was admitted in the intensive care unit consecutively to a road accident. Seven days after her admission, she developed a ventilation-associated pulmonary infection due to a multidrug-resistant P. aeruginosa that was treated with imipenem, colistin, metronidazole, and fluconazole for 14 days. Twenty-one days after the admission, the patient developed another pulmonary infection due to a multidrug-resistant A. baumannii only susceptible to colistin, resulting in her transfer to the French hospital. At the admission, the systematic screening of CPE using rectal swab samples revealed the presence of an OXA-48–producing K. pneumoniae (Table 1). After 24 hours, the patient developed a pyelonephritis due to a VIM-4–producing P. aeruginosa and a bronchitis due to an OXA-23–producing A. baumannii (Table 1), which were treated with amikacin, fosfomycin, and colistin. Although apyrexia was