Amino Acid Substitution in the Major Multidrug Efflux Transporter Protein AcrB Contributes to Low Susceptibility to Azithromycin in Haemophilus influenzae

Seyama, Shoji; Wajima, Takeaki; Nakaminami, Hidemasa; Noguchi, Norihisa

doi:10.1128/aac.01337-17

Cited by 10 publications

(6 citation statements)

References 22 publications

(28 reference statements)

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“…Deletions found in acrR of NUBL1772 were different from these reports. The results for NUBL1772 were consistent with those for H. influenzae isolates harboring AcrR with an early termination described by Seyama et al in terms of low-level acrB transcription and high efflux pump activity (22,23). Moreover, the results for NUBL1772 were consistent with those for H. influenzae isolates harboring AcrR with an early termination described by Kaczmarek et al in terms of the effect of efflux on ampicillin resistance (21).…”

Section: Resultssupporting

confidence: 87%

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

Kitaoka

Kimura

Kitanaka

et al. 2018

Antimicrob Agents Chemother

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The prevalence of β-lactamase-negative ampicillin-resistant (BLNAR) has become a clinical concern. In BLNAR isolates, amino acid substitutions in penicillin-binding protein 3 (PBP3) are relevant to the β-lactam resistance. Carbapenem-nonsusceptible isolates have been rarely reported. Through antimicrobial susceptibility testing, nucleotide sequence analysis of , encoding PBP3, and the utilization of a collection of clinical isolates in our laboratory, we obtained a carbapenem-nonsusceptible clinical isolate (NUBL1772) that possesses an altered PBP3 containing V525_N526insM. The aim of this study was to reveal the effect of altered PBP3 containing V525_N526insM on reduced carbapenem susceptibility. After generating recombinant strains with altered , we performed antimicrobial susceptibility testing and competitive binding assays with fluorescent penicillin (Bocillin FL) and carbapenems. Elevated carbapenem MICs were found for the recombinant strain harboring the entire gene of NUBL1772. The recombinant PBP3 of NUBL1772 also exhibited reduced binding to carbapenems. These results demonstrate that altered PBP3 containing V525_N526insM influences the reduced carbapenem susceptibility. The revertant mutant lacking the V525_N526insM exhibited lower MICs for carbapenems than NUBL1772, suggesting that this insertion affects reduced carbapenem susceptibility. The MICs of β-lactams for NUBL1772 were higher than those for the recombinant possessing of NUBL1772. NUBL1772 harbored AcrR with early termination, resulting in low-level transcription of and high efflux pump activity. These findings suggest that the disruption of AcrR also contributes to the reduced carbapenem susceptibility found in NUBL1772. Our results provide the first evidence that the altered PBP3 containing V525_N526insM is responsible for the reduced susceptibility to carbapenems in .

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Section: Resultssupporting

confidence: 87%

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

Kitaoka

Kimura

Kitanaka

et al. 2018

Antimicrob Agents Chemother

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“…The rate of multidrug resistance was also significantly higher in β -lactamase-positive HI strains than in β -lactamase-negative strains. Indeed, multidrug resistance might be conveyed by transferrable plasmid conjugative resistance elements [21–23].…”

Section: Discussionmentioning

confidence: 99%

Antibiotic Resistance Profiles of Haemophilus influenzae Isolates from Children in 2016: A Multicenter Study in China

Wang

Chen

et al. 2019

Canadian Journal of Infectious Diseases and Medical Microbiolog

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Background and Objective. Haemophilus influenzae (HI) is a common cause of community-acquired pneumonia in children. In many countries, HI strains are increasingly resistant to ampicillin and other commonly prescribed antibiotics, posing a challenge for effective clinical treatment. This study was undertaken to determine the antibiotic resistance profiles of HI isolates from Chinese children and to provide guidelines for clinical treatment. Methods. Our Infectious Disease Surveillance of Pediatrics (ISPED) collaboration group includes six children’s hospitals in different regions of China. The same protocols and guidelines were used by all collaborators for the culture and identification of HI. The Kirby–Bauer method was used to test antibiotic susceptibility, and a cefinase disc was used to detect β-lactamase activity. Results. We isolated 2073 HI strains in 2016: 83.9% from the respiratory tract, 11.1% from vaginal secretions, and 0.5% from blood. Patients with respiratory isolates were significantly younger than nonrespiratory patients (P<0.001). Of all 2073 strains, 50.3% were positive for β-lactamase and 58.1% were resistant to ampicillin; 9.3% were β-lactamase-negative and ampicillin-resistant. The resistance rates of the HI isolates to trimethoprim-sulfamethoxazole, azithromycin, cefuroxime, ampicillin-sulbactam, cefotaxime, and meropenem were 71.1%, 32.0%, 31.2%, 17.6%, 5.9%, and 0.2%, respectively. Conclusions. More than half of the HI strains isolated from Chinese children were resistant to ampicillin, primarily due to the production of β-lactamase. Cefotaxime and other third-generation cephalosporins could be the first choice for the treatment of ampicillin-resistant HI infections.

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“…Similar to ampicillin resistance, H. influenzae modifies the macrolide targets (50S ribosomal RNA and ribosome-binding proteins), leading to high levels of resistance [ 66, 67 ]. This mechanism is in addition to the ubiquitously present AcrAB multidrug-efflux pump which provides a baseline reduced susceptibility, and the authors of recent studies have reported changes in the AcrAB sequence to further contribute to resistance [ 68 ]. Another major alternative are quinolones, however, recently there has been an accumulation of reports of fluoroquinolone resistance [ 69–72 ] again through mutations in the targets, DNA gyrase (encoded by gyrA and gyrB ) and topoisomerase IV (encoded by parC and parE ); and thus again conferring resistance through a plasmid-independent mechanism, making it easy for resistances to arise independently through point mutations and/or spread through recombination.…”

Section: Introductionmentioning

confidence: 99%

The return of Pfeiffer’s bacillus: Rising incidence of ampicillin resistance in Haemophilus influenzae

Heinz

2018

Microbial Genomics

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Haemophilus influenzae, originally named Pfeiffer’s bacillus after its discoverer Richard Pfeiffer in 1892, was a major risk for global health at the beginning of the 20th century, causing childhood pneumonia and invasive disease as well as otitis media and other upper respiratory tract infections. The implementation of the Hib vaccine, targeting the major capsule type of H. influenzae, almost eradicated the disease in countries that adapted the vaccination scheme. However, a rising number of infections are caused by non-typeable H. influenzae (NTHi), which has no capsule and against which the vaccine therefore provides no protection, as well as other serotypes equally not recognised by the vaccine. The first line of treatment is ampicillin, but there is a steady rise in ampicillin resistance. This is both through acquired as well as intrinsic mechanisms, and is cause for serious concern and the need for more surveillance. There are also increasing reports of new modifications of the intrinsic ampicillin-resistance mechanism leading to resistance against cephalosporins and carbapenems, the last line of well-tolerated drugs, and ampicillin-resistant H. influenzae was included in the recently released priority list of antibiotic-resistant bacteria by the WHO. This review provides an overview of ampicillin resistance prevalence and mechanisms in the context of our current knowledge about population dynamics of H. influenzae.

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Amino Acid Substitution in the Major Multidrug Efflux Transporter Protein AcrB Contributes to Low Susceptibility to Azithromycin in Haemophilus influenzae

Cited by 10 publications

References 22 publications

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

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

Antibiotic Resistance Profiles of Haemophilus influenzae Isolates from Children in 2016: A Multicenter Study in China

The return of Pfeiffer’s bacillus: Rising incidence of ampicillin resistance in Haemophilus influenzae

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