Pharmacokinetics, Safety, and Efficacy of Glecaprevir/Pibrentasvir in Children With Chronic HCV: Part 2 of the DORA Study.

BACKGROUND AND AIMS: Glecaprevir/pibrentasvir (GLE/PIB) has shown high efficacy and safety in chronic HCV-infected adults and adolescents; data in children were limited. DORA part 2 is a phase 2/3, nonrandomized, open-label study evaluating the pharmacokinetics, efficacy, and safety of a pediatric formulation of GLE and PIB in children ages 3 to < 12 years. APPROACH AND RESULTS: Children with chronic HCV infection, genotype 1-6, with or without compensated cirrhosis, were divided into three cohorts by age-cohort 2 (9 to < 12 years), cohort 3 (6 to < 9 years), and cohort 4 (3 to < 6 years)-and given weight-based doses of GLE and PIB for 8, 12, or 16 weeks. Primary endpoints were sustained virologic response at posttreatment week 12 (SVR12) and steady-state exposure; secondary endpoints were rates of persistent viremia, relapse, and reinfection. Safety and laboratory abnormalities were assessed. Final pediatric dosages determined to be efficacious were 250 mg GLE + 100 mg PIB (in children weighing ≥ 30 to < 45 kg), 200 mg GLE + 80 mg PIB (≥ 20 to < 30 kg), and 150 mg GLE + 60 mg PIB (12 to < 20 kg). Of 80 participants enrolled and dosed, 96% (77/80) achieved SVR12. One participant, on the initial dose ratio, relapsed by posttreatment week 4; no participants had virologic failures on the final dose ratio of GLE 50 mg/PIB 20 mg. Two nonresponders prematurely discontinued the study. Most adverse events (AEs) were mild; no drug-related serious AEs occurred. Pharmacokinetic exposures were comparable to those of adults. CONCLUSIONS: A pediatric formulation of GLE/PIB was highly efficacious and well tolerated in chronic HCV-infected children 3 to < 12 years old.

Comparative genome analysis of global and Russian strains of community-acquired methicillin-resistant Staphylococcus aureus ST22, a 'Gaza clone'.

In this study, we identified the relationship between the genetic lineage of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) sequence type 22 (ST22) from Russia and other regions. Sixty ST22 isolates from Russia were characterised through whole-genome sequencing. To evaluate the phylogenetic relationship of Russian isolates with the global ST22 population, we analysed 1283 genomes obtained from NCBI's GenBank. The phylogenetic tree of the ST22 global population consisted of three main clusters (A, B and C). The first (cluster A) was represented by EMRSA-15 isolates, the second (cluster B) by heterogeneous isolates from different regions harbouring different sets of virulence genes, and the third (cluster C) by isolates from the Middle East previously recognised as 'Gaza clone' and similar isolates from Russia. Presence of the toxic shock syndrome toxin (tsst) and elastin-binding protein S (ebpS) genes as well as the hypothetical proteins NCTC13616_00051 and NCTC13616_00047 were the most useful factors in discriminating ST22 lineages. Although the CA-MRSA 'Gaza clone' was mainly recovered from carriers, its widespread occurrence is a cause for concern. Differentiation of the 'Gaza clone' from other MRSA lineages is necessary for planning infection control measures.

Co-production of MCR-1 and NDM-1 by Escherichia coli sequence type 31 isolated from a newborn in Moscow, Russia.

An Escherichia coli sequence type 31 isolate co-harbouring mcr-1 and blaNDM-1 genes on the plasmids of Incl2 and IncC groups, respectively, was recovered from a newborn with ventilator-associated pneumonia in Moscow, Russia. The convergence of polymyxin and carbapenem resistance and its expansion beyond Southeast Asia is a serious threat to human health.

The emergence of hypervirulent blaNDM-1-positive Klebsiella pneumoniae sequence type 395 in an oncology hospital.

Fifteen hypermucoviscous isolates (13 blaNDM-1-positive) obtained from 11 oncology patients were analyzed by whole genome sequencing, and selected isolates were assessed in a murine model of sepsis. ST395/K2 isolates harboring rmpA, rmpA2, peg-344, aerobactin, enterobactin, yersiniabactin, type I fimbriae, etc. displayed maximal virulence in the mouse lethality assay (LD50 = 102 CFU). ST147/K20 isolates lacking yersiniabactins were relatively less virulent (LD50 = 104 CFU), ST395/K2 isolates lacking rmpA, rmpA2, peg-344, and aerobactin, but harboring yersiniabactin demonstrated minimal virulence (LD50 = 105 CFU). Isolates represent various paths and stages of evolution directed towards convergence of multidrugresistant classical Klebsiella pneumoniae and hypervirulent K. pneumoniae.

Multicenter study of serotype distribution of Streptococcus pneumoniae nasopharyngeal isolates from healthy children in the Russian Federation after introduction of PCV13 into the National Vaccination Calendar.

Russia introduced PCV13 in 2014. We studied the serotype composition of S. pneumoniae isolated from the nasopharynx of healthy children younger than 6 years in St. Petersburg, Smolensk, Perm, Krasnoyarsk, Khanty-Mansiysk and Khabarovsk, between 2016 and 2018. 2.4% of children had completed a 3-dose course of PCV13, while 25.6% had received 1 or 2 doses. Pneumococcal DNA detection by PCR demonstrated S. pneumoniae in 37.2% of samples with regional variation between sites (27.3 to 56.9%). There was little difference between vaccinated, partially vaccinated and un-vaccinated children. Children who had received at least 1 dose of PCV13 had lower carriage rates of vaccine serotypes than their unvaccinated peers (49.9 vs. 61.4%; p < 0.001). Children who had received at least 1 dose of PCV13 showed increased carriage rates of non-vaccine serotypes (50 vs 38.6%; P < 0.001). Especially serogroup 15AF was more prevalent among fully immunized children than among their peers (12.5 vs 2.7%; P < 0.05).

In Vitro Ceftaroline Resistance Selection of Methicillin-Resistant Staphylococcus aureus Involves Different Genetic Pathways.

The pathways in the development of ceftaroline resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolates belonging to the ST8, ST239, and ST228 were evaluated. Ceftaroline-resistant derivatives were isolated through selection during 40 passages. Ceftaroline MIC measurements and whole-genome sequencing were performed after 5, 20, and 40 passages. In two ST8 derivative isolates, ceftaroline MIC increased up to 128 mg/L. Mutations were acquired in gdpP and graS in one isolate after 20 passages and in gdpP in another after 40 passages. MIC for two ST239 derivatives increased to 128 mg/L. Substitutions in Pbp4 and polymorphisms in the upstream region of pbp4 were identified in both derivatives after 40 passages. In one isolate, additional mutation in gdpP and deletion in graR were detected. In an ST228 derivative, MIC increased to 32 mg/L with one mutation in penicillin-binding protein 2a (Y446N) detected after five passages and a second (E447K) after 20 passages. Three pathways in the development of ceftaroline resistance were identified. For ST8 and ST239 derivatives mutations were detected in gdpP and pbp4, respectively, whereas in ST228 - in mecA. Most derivatives harbored additional mutations whose potential role in the development of resistance has not been determined.

Observational study of nasopharyngeal carriage of Neisseria meningitidis in applicants to a military academy in the Russian Federation.

OBJECTIVE: To determine the carriage and the serogroup distribution of Neisseria meningitidis in military academy applicants in the Russian Federation. DESIGN: This was a prospective, observational study of adults aged >18years from a military academy; applicants who had samples taken on arrival (Day 1), and applicants who had samples taken after passing exams (Day 30) and 60days after arrival. N. meningitidis serogrouping was determined by slide agglutination tests of isolates and real-time PCR. RESULTS: Samples were provided by 671 applicants on Day 1 and 261 applicants on Day 30, with 232 of these also providing samples on Day 60. N. meningitidis was detected in 16.2% of samples from Day 1, 7.7% of samples from Day 30 and 15.9% of samples from Day 60. Serogroup composition was most diverse at Day 1, with serogroups B and W dominant (40% [17/43 isolates] and 9% [4/43], respectively; 30% [13/43] ungroupable); by Day 60, there was a low diversity, with 58% (14/24 isolates) serogroup W. CONCLUSIONS: While carriage of N. meningitidis in this study appeared stable, there was an increase in carriers of serogroup W in this population. Given recent increases in outbreaks attributed to serogroup W, further monitoring may be considered.

Retrospective surveillance of antibiotic use in maternity wards and neonatal intensive care units in Saint Petersburg, Russia.

Antibiotic overuse in infants is associated with an increased risk of serious adverse events. Development of antibiotic stewardship programs aimed at reducing overall antibiotic consumption requires epidemiological surveillance. Retrospective surveillance and evaluation of all antibiotics provided to every infant admitted to maternal wards or neonatal intensive care units (NICUs) from 01 January 2014 to 31 December 2014 were performed in five medical centers of Saint Petersburg, Russia. Types of antibiotics and dates of administration were recorded. Antibiotic use was quantified by length of therapy (length of therapy, LOT, per 1000 patient-days, PD) and days of therapy (DOT/1000 PD). An additional parameter named "instant DOT/1000 PD" was introduced by authors for assessment of longitudinal patterns of administrations. Antibiotic load was 825.6 DOT/1000 PD in maternity wards and 1425.8 DOT/1000 PD in the NICUs. These levels are two to four times higher than DOTs reported in the USA for a level III NICU (348 DOT/1000PD). Antibiotic load was associated with the length of hospital stay (LOS) and birth weight. These associations were distorted when assessed using the conventional parameters, LOT and DOT, because they do not reflect the longitudinal component of treatment and underestimate antibiotic load when a patient stays in hospital without treatment. The proposed additional parameter successfully overcame these flaws and uncovered hidden associations. Severe overuse of antibiotics may be taking place in Russia and antibiotic stewardship development should be urged. Instant DOT/1000 PD is a more powerful tool in assessing treatment patterns than DOT/1000 PD.

Molecular epidemiology and antibiotic resistance of methicillin-resistant Staphylococcus aureus circulating in the Russian Federation.

The aim of this study was to investigate the patterns of antimicrobial resistance and molecular features of methicillin-resistant Staphylococcus aureus (MRSA) isolates in Russia. Isolates recovered from hospital patients (n=480), healthy medical personnel (n=25), and healthy carriers (n=13) were included in the study. Hospital-acquired MRSA (HA-MRSA) demonstrated high resistance to ciprofloxacin, gentamicin, and chloramphenicol (76%-92%), moderate - to tetracycline, erythromycin, clindamycin, and rifampicin (38%-54%), and low - to fusidic acid, co-trimoxazole, mupirocin, and daptomycin (2%-7%). Elevated MIC (2.0µg/ml) of vancomycin was detected in 26% of isolates. All isolates were susceptible to linezolid and tigecycline. Multilocus sequence typing (MLST) revealed that CC8 isolates (ST8+ST239) constituted 83.1% of HA-MRSA and that this genetic lineage dominated in all regions from Krasnoyarsk to Saint Petersburg. A local ST239 variant harboring the tst gene (ST239Kras) was detected in Krasnoyarsk. The other HA-MRSA isolates belonged to clonal complex 5 (CC5) (21 isolates, 12.2%) and CC22 (2, 1.2%). The majority of CC5 isolates were affiliated with sequence type 228 (ST228) and were characterized with decreased susceptibility to ceftaroline (MIC=2µg/ml). We also detected, for the first time in Russia, livestock-associated MRSA (LA-MRSA) from clusters CC398 and CC97 in humans. Among the 2053 healthy persons screened for nasal carriage of S. aureus, the bacteria were isolated from 426 (21%); among them, 13 carried isolates identified as community-associated MRSA (CA-MRSA). Eleven of 13 CA-MRSA isolates belonged to ST22 (spa types t223, t3243, and t3689; SCCmec types IVa and IVc, agr type I, tst-positive) and were similar to the EMRSA-15/Middle Eastern variant (Gaza strain).

Genetic Environment of the blaKPC-2 Gene in a Klebsiella pneumoniae Isolate That May Have Been Imported to Russia from Southeast Asia.

The nucleotide sequence of a blaKPC-2-harboring plasmid (pKPCAPSS) from Klebsiella pneumoniae ST273 isolated in Saint Petersburg, Russia, from a patient with history of recent travel to Vietnam is presented. This 127,970-bp plasmid possessed both IncFII and IncR replicons. blaKPC-2 was localized on a hypothetical mobile element. This element was flanked by 38-bp inverted Tn3 repeats and included a Tn3-specific transposase gene, macrolide resistance operon (mphA-mrx-mphR), and a fragment of blaTEM with unique polymorphisms.

Surveillance of antimicrobial susceptibility of Enterobacteriaceae pathogens isolated from intensive care units and surgical units in Russia.

A total of 473 strains of Enterobacteriaceae, including Escherichia coli, Klebsiella spp., Proteus spp., Citrobacter spp., Enterobacter spp., Serratia spp. and Providencia spp., were isolated from patients admitted to intensive care units and surgical units in Russia. About 90% of the isolates carried factors resistant to beta-lactams. The isolation rates of the extended-spectrum beta-lactamase (ESBL) producer defined in this study among E. coli, Klebsiella spp. and Proteus spp. were 45%, 48% and 17%, respectively. In the settings with high prevalence of the ESBL producer, flomoxef, which belongs to the oxacephem subgroup, and carbapenems retain their activity. The MIC50 of flomoxef, meropenem and imipenem against total isolates were 1 µg/mL, ≤ 0.063 µg/mL and 0.25 µg/mL, respectively. Fifty-five carbapenem-resistant strains were isolated in this study. The carbapenem resistant rates of E. coli, Klebsiella spp. and Proteus spp. were 3%, 16% and 29%, respectively

Emergence of carbapenemase-producing Gram-negative bacteria in Saint Petersburg, Russia.

The emergence and spread of carbapenemase-producing Gram-negative bacteria represents a serious public health concern. Here we show that of 477 Gram-negative isolates collected from 18 hospitals between November 2011 and February 2013 in Saint Petersburg (Russia), minimum inhibitory concentrations (MICs) were greater than the European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off value of at least one carbapenem antibiotic in 101 isolates (21.2%). The bla(NDM-1) gene was detected by PCR in 17 Klebsiella pneumoniae and 1 Acinetobacter nosocomialis isolate. Multilocus sequence typing (MLST) revealed that all NDM-1-producing K. pneumoniae isolates belonged to sequence type 340 (ST340) and harboured genes encoding additional ß-lactamases; presence of the bla(CTX-M-1-like) gene correlated with aztreonam resistance, whilst its absence correlated with susceptibility. The epidemiological situation in Saint Petersburg can be assessed as regional spread of NDM-1-producers. The bla(KPC-2) gene was detected in two K. pneumoniae isolates (ST258 and ST273) and one Enterobacter cloacae isolate. Two E. cloacae isolates harboured the bla(VIM-4) gene, and one K. pneumoniae (ST395) isolate harboured the bla(OXA-48) gene. In NDM-1-producers, MICs of biapenem were the lowest compared with those of other carbapenems. Most isolates were susceptible to tigecycline and polymyxin, except for one K. pneumoniae isolate that was found to be polymyxin-resistant and one E. cloacae isolate that was tigecycline-resistant. Only one patient with a urinary tract infection caused by KPC-2-producing K. pneumoniae had a history of travel abroad (Southeast Asia). Thus, there is an actual threat of the emergence of an alarming endemic situation with NDM-1-producers in Saint Petersburg.