Objective. To assess rates of antimicrobial resistance and production of the clinically important acquired resistance mechanisms (extended spectrum beta-lactamases [ESBL] and carbapenemases) in nosocomial strains of Enterobacterales, and to determine genotypes and prevalence of “international high-risk clones” among carbapenemase-producing Klebsiella pneumoniae isolated in various Russian regions within the “MARATHON 2015–2016“ study. Materials and Methods. A total of 2786 non-duplicate nosocomial isolates of Enterobacterales, including 1316 isolates of K. pneumoniae and 837 isolates of Escherichia coli isolated in 49 hospitals from 25 cities in Russia in 2015–2016 were studied.

Pneumococcal infections remain a major medical problem associated with high morbidity and mortality. Moreover, the resistance of Streptococcus pneumoniae to conventional antibiotics is constantly growing. The implementation of pneumococcal conjugate vaccines (PCVs) in the last decade has dramatically reduced the incidence of the vaccine type-associated invasive pneumococcal diseases in many countries. However, information on the seroepidemiology of S. pneumoniae in Russia is limited. We report the results of serotyping and antibiotic susceptibility testing performed on 863 non-invasive pneumococcal isolates collected prospectively in 2009-2013 from children (median age 3.5 years) who sought medical care at five pediatric hospitals in Moscow. The isolates were recovered from the nasopharynx (71.2%), middle ear fluid (14.3%), and lower respiratory tract specimens (13.6%). In total, we identified 45 different serotypes. The six leading serotypes (prevalence >5%) included 19F (21.7%), 6B (12.8%), 23F (10.1%), 14 (9.0%), 6A (8.4%), and 3 (7.5%). Serotype 19A isolates had a prevalence of 2.3%. The proportion of PCV-13 serotypes was 78%; the coverage by PCV-7 was 58.2% and was similar to that of PCV-10 (59.8%). The rate of multidrug-resistant pneumococci (i.e., resistant to ≥3 antimicrobials) was 22%. The majority of the multidrug-resistant isolates were serotype 6B, 14, 19A, and 19F. Penicillin non-susceptibility was displayed by 28% of the isolates. The resistance rate to erythromycin was 26%. Among the examined erythromycin-resistant strains, 54% had the erm(B) gene and 13% had the mef gene as a single resistance determinant, whereas both determinants were found in 31% of these strains. Our data predict a good coverage of the circulating S. pneumoniae by the PCVs and could be useful for evaluating the serotype distribution in support of the introduction of PCV in Russia. In addition, the antimicrobial resistance rate of S. pneumoniae in Russia is substantial, and the emergence of pneumococcal strains with a dual macrolide resistance mechanism is alarming.

SUMMARY: Clonal changes of serotype 19A pneumococci have been appreciated in conjunction with growing prevalence of this serotype after implementation of the seven-valent pneumococcal conjugate vaccine (PCV7). In the present study, we characterized serotype 19A pneumococci collected in Russia within a decade preceding the implementation of PCV vaccination and described their clonal evolution. We retrospectively analyzed non-invasive serotype 19A isolates collected in 2002–2013. All isolates were subjected to multilocus sequence typing, antimicrobial susceptibility testing, determination of macrolide resistance genotype, molecular detection of pilus islet (PI) carriage, sequencing of penicillin-binding protein (PBP) genes. A total of 49 serotype 19A isolates represented 25 sequence types, of which 14 were newly described. The majority of isolates were distributed among clonal complex (CC) 663 (28%), CC230 (25%), CC156, and CC320 (14% each). CC663 and CC156 dominated in 2003, but were replaced by CC230 and CC320 later on; CC320 was only evident starting 2010. All isolates of CC663 and CC156 carried PI1; CC320 possessed both PI1 and PI2. The overall rate of altered amino acids in penicillin-nonsusceptible isolates was 13·9%, 7·2%, and 8·7% for PBP1a, PBP2b, and PBP2x, respectively. Our findings demonstrate that the clonal structure of serotype 19A pneumococci may evolve without PCV pressure.

Carbapenem-nonsusceptible (Carba-NS) Acinetobacter baumannii has emerged as an important cause of nosocomial infections. In the present study, we characterized 91 Carba-NS A. baumannii isolates collected from patients of surgical departments and intensive care units at three hospitals in Moscow in 2012–2015. Multilocus sequence typing (MLST) using the Oxford (Oxf) scheme identified 16 sequence types (STs) of three clonal complexes (CCs), including CC92 ^Oxf (67%), CC109 ^Oxf (1%), CC944 ^Oxf (29%), and the singleton ST1100 ^Oxf (3%). CC944 ^Oxf was composed of ST944 ^Oxf ( n = 16) and two of its newly described single locus variants ST1103 ^Oxf ( n = 3) and ST1104 ^Oxf ( n = 7); all the three STs were identical to the Pasteur (Pas) MLST scheme ST78. All CC944 ^Oxf /ST78 ^Pas isolates were bla _OXA-40-like positive and all but one isolate harbored a bla _CTX-M-like gene. ST944 ^Oxf was the only ST found in each of the three study hospitals. Biofilm growth capacity was similar among Carba-NS and nonclonal carbapenem-susceptible isolates. Our data demonstrate the predominance of two clonal lineages among Carba-NS A. baumannii . One of these, the uncommon bla _OXA-40-like / bla _CTX-M-like -positive clone of CC944 ^Oxf /ST78 ^Pas , seems to be endemic in Russia.

Objective. Objectives. To assess the rates of antibiotic resistance and production of acquired carbapenemases in nosocomial strains of Acinetobacter spp., and to determine the genotypes and prevalence of “international high-risk clones” among nosocomial strains of Acinetobacter baumannii isolated in various regions of Russia within the “MARATHON 2015–2016” study. Materials and Methods. A total of 1005 non-duplicate nosocomial isolates of Acinetobacter spp., including 975 isolates of A. baumannii, collected in 44 hospitals from 25 cities in Russia in 2015– 2016 were studied.