Serotypes and Clonal Composition of Streptococcus pneumoniae Isolates Causing IPD in Children and Adults in Catalonia before 2013 to 2015 and after 2017 to 2019 Systematic Introduction of PCV13.

The goal of this study was to investigate the distribution of serotypes and clonal composition of Streptococcus pneumoniae isolates causing invasive pneumococcal disease (IPD) in Catalonia, before and after systematic introduction of PCV13. Pneumococcal strains isolated from normally sterile sites obtained from patients of all ages with IPD received between 2013 and 2019 from 25 health centers of Catalonia were included. Two study periods were defined: presystematic vaccination period (2013 and 2015) and systematic vaccination period (SVP) (2017 to 2019). A total of 2,303 isolates were analyzed. In the SVP, there was a significant decrease in the incidence of IPD cases in children 5 to 17 years old (relative risk [RR] 0.61; 95% confidence interval [CI] 0.38 to 0.99), while there was a significant increase in the incidence of IPD cases in 18- to 64-year-old adults (RR 1.33; 95% CI 1.16 to 1.52) and adults over 65 years old (RR 1.23; 95% CI 1.09 to 1.38). Serotype 8 was the major emerging serotype in all age groups except in 5- to 17-year-old children. In children younger than 5 years old, the main serotypes in SVP were 24F, 15A, and 3, while in adults older than 65 years they were serotypes 3, 8, and 12F. A significant decrease in the proportions of clonal complexes CC156, CC191, and ST306 and an increase in those of CC180, CC53, and CC404 were observed. A steady decrease in the incidence of IPD caused by PCV13 serotypes indicates the importance and impact of systematic vaccination. The increase of non-PCV13 serotypes highlights the need to expand serotype coverage in future vaccines and rethink vaccination programs for older adults. IMPORTANCE We found that with the incorporation of the PCV13 vaccine, the numbers of IPD cases caused by serotypes included in this vaccine decreased in all of the age groups. Still, there was an unforeseen increase of the serotypes not included in this vaccine causing IPD, especially in the >65-year-old group. Moreover, a significant increase of serotype 3 included in the vaccine has been observed; this event has been reported by other researchers. These facts call for the incorporation of more serotypes in future vaccines and a more thorough surveillance of the dynamics of this microorganism.

Mechanisms of reduced susceptibility to amoxycillin-clavulanic acid in Escherichia coli strains from the health region of Tortosa (Catalonia, Spain).

This study investigated the mechanisms involved in reduced susceptibility to amoxycillin-clavulanic acid and the prevalence of enzymes compatible with inhibitor-resistant TEM (IRT) beta-lactamases produced by Escherichia coli isolates from patients in north-eastern Spain. The resistance mechanisms of 158 strains showing resistance or intermediate resistance to amoxycillin-clavulanic acid among 1122 ampicillin-resistant clinical isolates of E. coli were assessed on the basis of their beta-lactam resistance phenotypes. beta-Lactamases produced by strains showing resistant phenotypes suggestive of inhibitor-resistant penicillinase production were characterised by their isoelectric point. Specific activity and the concentration of clavulanic acid required to inhibit beta-lactamase activity by 50% (IC50) were determined in strains harbouring enzymes that focused at pI 5.2 or 5.4 in order to achieve presumptive identification of IRT beta-lactamases. Resistance phenotypes were consistent with overproduction of TEM-1, TEM-2 or SHV-1 beta-lactamases in 56 strains, with AmpC cephalosporinase hyperproduction in 46 strains, and with production of inhibitor-resistant penicillinases in 49 strains. Of the latter isolates, 17 produced moderately high or high levels of enzymes co-focusing with TEM-1, 17 produced enzymes co-focusing with OXA-1 (n = 12) or with PSE-1 (n = 5), either alone or in association with TEM-1, while only 15 produced enzymes with a phenotype characteristic of IRT beta-lactamases. It was concluded that resistance to amoxycillin-clavulanic acid in E. coli isolates from this area was mainly associated with presumptive overproduction of TEM-1, TEM-2 or SHV-1 beta-lactamases (46%) or of AmpC cephalosporinase (29%), while the occurrence of enzymes categorised as IRT beta-lactamases was unusual (9.5%).