Emergence of clonally related multidrug resistant Haemophilus influenzae with penicillin-binding protein 3-mediated resistance to extended-spectrum cephalosporins, Norway, 2006 to 2013

Abstract

Resistance to cephalosporins in Haemophilus influenzae is usually caused by characteristic alterations in penicillin-binding protein 3 (PBP3), encoded by the ftsI gene. Resistance to extended-spectrum cephalosporins is associated with high-level PBP3-mediated resistance (high-rPBP3), defined by the second stage S385T substitution in addition to a first stage substitution (R517H or N526K). The third stage L389F substitution is present in some high-rPBP3 strains. High-rPBP3 H. influenzae are considered rare outside Japan and Korea. In this study, 30 high-rPBP3 isolates from Norway, collected between 2006 and 2013, were examined by serotyping, multilocus sequence typing (MLST), ftsI sequencing, detection of betalactamase genes and minimum inhibitory concentration (MIC) determination. MICs were interpreted according to clinical breakpoints from the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Respiratory isolates predominated (proportion: 24/30). The 30 isolates included one serotype f isolate, while the remaining 29 lacked polysaccharide capsule genes. Resistance to extended-spectrum cephalosporins (cefixime, 29 isolates/30 isolates; cefepime, 28/30; cefotaxime, 26 /30; ceftaroline, 26/30; ceftriaxone, 14/30), beta-lactamase production (11/30) and co-resistance to non-beta-lactams (trimethoprim-sulfamethoxazole, 13/30; tetracycline, 4/30; chloramphenicol, 4/30; ciprofloxacin, 3/30) was frequent. The N526K substitution in PBP3 was present in 23 of 30 isolates; these included a blood isolate which represents the first invasive S385T + N526K isolate reported from Europe. The L389F substitution, present in 16 of 30 isolates, coincided with higher beta-lactam MICs. Non-susceptibility to meropenem was frequent in S385T + L389F + N526K isolates (8/12). All 11 beta-lactamase positive isolates were TEM-1. Five clonal groups of two to 10 isolates with identical MLST-ftsI allelic profiles were observed, including the first reported high-rPBP3 clone with TEM-1 beta-lactamase and co-resistance to ciprofloxacin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole. Prior to this study, no multidrug resistant high-rPBP3 H. influenzae had been reported in Norway. Intensified surveillance of antimicrobial resistance is needed to guide empiric therapy.

Carbapenem-Nonsusceptible Haemophilus influenzae with Penicillin-Binding Protein 3 Containing an Amino Acid Insertion

“…According to the ftsI grouping proposed by Skaare et al, four isolates belonged to group IIIϩ, two isolates belonged to group II, and NUBL1772 was not classified because it was found to harbor the V525_N526insM in PBP3 (9). The deduced amino acid sequence of PBP3 of NUBL1772 is aligned in Fig.…”

“…(Tokyo, Japan) and sequenced using BigDye Terminator v3.1 with a 3730xl DNA analyzer (Thermo Fisher Scientific, Waltham, MA). Although several classifications for PBP3 amino acid substitution patterns have been suggested, the grouping proposed by Skaare et al was determined to be more relevant to reduced carbapenem susceptibility (9). According to the Skaare classification, deduced PBP3 amino acid sequences from ftsI gene sequences were grouped as follows: group I (R517H) and group II (N526K) as low rPBP3; group III (S385T, N526K), group IIIϩ (S385T, L389F, and N526K), group III-like (S385T, R517H), and group III-likeϩ (S385T, L389F, and R517H) as high rPBP3.…”

“…though the number of reports concerning such strains is limited, all were reported to harbor altered PBP3 (7)(8)(9). In addition, slowed drug influx or direct efflux regulation appeared to be involved in reduced carbapenem susceptibility (10).…”

Acute otitis media in the children: etiology and the problems of antibacterial therapy

“…Устойчивость H. influenzae к цефалоспоринам связана с изменениями структуры пенициллинсвязывающего белка 3 (pbp3), кодируемого геном ftsl. Кроме того, у гемофильной палочки может наблюдаться резистентность к ципрофлоксацину, тетрациклину, хлорамфениколу и триметопримсульфаметоксазолу [30].…”

Haemophilus influenzae with Non-Beta-Lactamase-Mediated Beta-Lactam Resistance: Easy To Find but Hard To Categorize

“…Strains with low-level PBP3-mediated resistance (low-rPBP3) possess the R517H (group I) or the N526K (group II) substitution, whereas strains with high-level resistance (high-rPBP3) are characterized by the additional substitution S385T (2,3). The distinction is clinically important because high-rPBP3 strains express higher resistance to extended-spectrum cephalosporins (1,2,(4)(5)(6). Group II low-rPBP3 is the predominating genotype in Australia (7), Europe (8,9), and North America (6,10), whereas high-rPBP3 strains predominate in Japan and Korea (6,11).…”