SARS-CoV-2 mRNA vaccination induces stem cell memory T cells specific for the virus that persist up to 6 months.

To perform the first multinational Enterobacter cloacae clonality study, using the MLST scheme newly developed in Japan. The analysis included 195 rectal carriage E. cloacae isolates resistant to expanded-spectrum cephalosporins (ESCs), collected from patients in 12 hospital units across Europe and Israel. All of the isolates were typed by PFGE and 173 isolates were subjected to MLST. ESC resistance was analysed phenotypically; genes encoding ESBLs and carbapenemases were identified by PCR and sequencing. MLST distinguished 88 STs, which correlated with the PFGE data. PFGE was more discriminatory, producing 129 pulsotypes (169 patterns). Numerous STs were observed in several countries each. The most widespread were ST66, ST78, ST108 and ST114, each having at least 10 isolates from three to five countries, diversified into multiple pulsotypes, with clusters of related isolates in one or more centres. Analysis of the STs against the MLST database revealed several epidemic clonal complexes, such as those with central genotypes ST74 (including ST78) or ST114 (including ST66). ESC resistance was equally related to overexpression of the AmpC cephalosporinase and to ESBL production. Among ESBL producers some spreading subclones were identified, including specific ST66, ST78 and ST114 pulsotypes, associated with CTX-M-15 production. Several isolates produced carbapenemase VIM-1 or KPC-2. Together with the information available in the MLST database, our results suggest that, like Escherichia coli and Klebsiella pneumoniae, E. cloacae harbours clonal lineages of increased epidemic potential that may be associated with resistance spread.

The prospective project MOSAR was conducted in five rehabilitation units: the Berck Maritime Hôpital (Berck, France), Fondazione Santa Lucia (Rome, Italy), Guttmann Institute (GI; Barcelona, Spain), and Loewenstein Hospital and Tel-Aviv Souraski Medical Center (TA) (Tel-Aviv, Israel). Patients were screened for carriage of Enterobacteriaceae resistant to expanded-spectrum cephalosporins (ESCs) from admission until discharge. The aim of this study was to characterize the clonal structure, extended-spectrum β-lactamases (ESBLs), and acquired AmpC-like cephalosporinases in the Escherichia coli populations collected. A total of 376 isolates were randomly selected. The overall number of sequence types (STs) was 76, including 7 STs that grouped at least 10 isolates from at least three centers each, namely, STs 10, 38, 69, 131, 405, 410, and 648. These clones comprised 65.2% of all isolates, and ST131 alone comprised 41.2%. Of 54 STs observed only in one center, some STs played a locally significant role, like ST156 and ST393 in GI or ST372 and ST398 in TA. Among 16 new STs, five arose from evolution within the ST10 and ST131 clonal complexes. ESBLs and AmpCs accounted for 94.7% and 5.6% of the ESC-hydrolyzing β-lactamases, respectively, being dominated by the CTX-M-like enzymes (79.9%), followed by the SHV (13.5%) and CMY-2 (5.3%) types. CTX-M-15 was the most prevalent β-lactamase overall (40.6%); other ubiquitous enzymes were CTX-M-14 and CMY-2. Almost none of the common clones correlated strictly with one β-lactamase; although 58.7% of ST131 isolates produced CTX-M-15, the clone also expressed nine other enzymes. A number of clone variants with specific pulsed-field gel electrophoresis and ESBL types were spread in some locales, potentially representing newly emerging E. coli epidemic strains.

The objective of this study was to perform a multinational survey of patients' colonization by metallo-β-lactamase (MBL)-producing Enterobacteriaceae, including their molecular characterization. Patients in 18 hospital units across Europe and Israel (n = 17 945) were screened between mid-2008 and mid-2011. MBL-producing isolates were typed by PFGE and MLST. MBL genes were amplified and sequenced within their integrons. Plasmids with MBL genes were analysed by nuclease S1 plus hybridization profiling, mating and transformation assays, and by PCR-based replicon typing. Ninety-one patients in nine centres (six countries), including 62 patients in two Greek ICUs, carried 94 non-duplicate MBL-producing organisms. Klebsiella pneumoniae isolates from Greece dominated (n = 57) and belonged mainly to ST147, ST36 and ST383. All but one of the isolates expressed VIM-1-type MBLs. Isolates of Greek origins produced five enzymes, including new VIM-39, encoded by class 1 integrons of four types. In-e541-like elements prevailed, comprising six variants located on IncR, IncFII_K, IncR + FII_K, IncR + A/C or non-typeable plasmids. The other group were new In4873 and In4863, being the first In416-like elements identified in Greece, which were present on IncA/C or non-typeable plasmids. Isolates from other countries produced only VIM-1 and the major integron was In916, identified in 16 organisms from France, Italy and Spain. In916 was carried by four plasmid types, including IncA/C, IncFII_K and IncHI2. Other integrons included a new element, In3103, in Spain and In110 identified only in Latvia. This study provided fully comparable data on the occurrence and molecular characteristics of VIM-producing Enterobacteriaceae in a group of hospital units across Europe, documenting recent changes in their epidemiology.

The international project MOSAR was conducted in five rehabilitation centers; patients were screened for rectal carriage of extended-spectrum β-lactamase (ESBL)-producing members of the Enterobacteriaceae . Among 229 Klebsiella pneumoniae isolates, four clonal groups (CG) or complexes (CC) prevailed: CG17 in France, CG101 in Italy, CG15 in Spain, and CC147 in Israel. ESBLs, mainly CTX-Ms, were produced by 226 isolates; three isolates expressed AmpC-like cephalosporinases. High genetic diversity of K. pneumoniae populations was observed, with specific characteristics at each center.