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Wan TW, Huang YT, Lai JH, Chao QT, Yeo HH, Lee TF, Chang YC, Chiu HC. The emergence of transposon-driven multidrug resistance in invasive nontypeable Haemophilus influenzae over the last decade. Int J Antimicrob Agents 2024; 64:107319. [PMID: 39233216 DOI: 10.1016/j.ijantimicag.2024.107319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 08/12/2024] [Accepted: 08/26/2024] [Indexed: 09/06/2024]
Abstract
Nontypeable Haemophilus influenzae (NTHi), once considered a harmless commensal, has emerged as a significant concern due to the increased prevalence of multidrug-resistant (MDR) strains and their association with invasive infections. This study aimed to explore the epidemiology and molecular resistance mechanisms of 51 NTHi isolates collected from patients with invasive infections in northern Taiwan between 2011 and 2020. This investigation revealed substantial genetic diversity, encompassing 29 distinct sequence types and 18 clonal complexes. Notably, 68.6% of the isolates exhibited ampicillin resistance, with 28 categorised as MDR and four isolates were even resistant to up to six antibiotic classes. Among the MDR isolates, 18 pulsotypes were identified, indicating diverse genetic lineages. Elucidation of their resistance mechanisms revealed 18 β-lactamase-producing amoxicillin-clavulanate-resistant (BLPACR) isolates, 12 β-lactamase-producing ampicillin-resistant (BLPAR) isolates, and 5 β-lactamase-nonproducing ampicillin-resistant (BLNAR) isolates. PBP3 analysis revealed 22 unique substitutions in BLPACR and BLNAR, potentially contributing to cephem resistance. Notably, novel transposons, Tn7736-Tn7739, which contain critical resistance genes, were discovered. Three strains harboured Tn7739, containing seven resistance genes [aph(3')-Ia, blaTEM-1, catA, sul2, strA, strB, and tet(B)], while four other strains carried Tn7736, Tn7737, and Tn7738, each containing three resistance genes [blaTEM-1, catA, and tet(B)]. The emergence of these novel transposons underscores the alarming threat posed by highly resistant NTHi strains. Our findings indicated that robust surveillance and comprehensive genomic studies are needed to address this growing public health challenge.
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Affiliation(s)
- Tsai-Wen Wan
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Yu-Tsung Huang
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Jian-Hong Lai
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Qiao-Ting Chao
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Hui-Hui Yeo
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Tai-Fen Lee
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Yung-Chi Chang
- Department of Graduate Institute of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Hao-Chieh Chiu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan.
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Slotved HC, Johannesen TB, Stegger M, Dalby T, Fuursted K. National Danish surveillance of invasive clinical Haemophilus influenzae isolates and their resistance profile. Front Microbiol 2023; 14:1307261. [PMID: 38075872 PMCID: PMC10702724 DOI: 10.3389/fmicb.2023.1307261] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/07/2023] [Indexed: 06/29/2024] Open
Abstract
INTRODUCTION This study aimed to investigate the epidemiology, serotype distribution, phenotypical antibiogram, and molecular resistance gene characteristics of invasive Haemophilus influenzae infections in Denmark from 2014 to 2022. Additionally, the potential impact of outdoor temperature and COVID-19 restrictions on the epidemiology of H. influenzae was assessed. MATERIALS AND METHODS Invasive H. influenzae isolates were received from patients with positive culture results from cerebrospinal fluid, blood, or other sterile sites. Sample data were obtained from the Danish laboratory surveillance system/MiBa database, and whole-genome sequencing (WGS) was performed on the isolates. The incidence rates and distribution of H. influenzae cases were analyzed, and antibiotic susceptibility were assessed. RESULTS A total of 1,007 invasive H. influenzae cases were identified, with serotyping conducted for 752 (74.7%) isolates. The median incidence per year of H. influenzae was 2.0 cases per 100,000, with the highest incidence in 2014 and the lowest in 2020. The majority of H. influenzae isolates were non-typeable H. influenzae (NTHi), while the most prominent serotypes were serotype f followed by serotype b. Bacteremia cases accounted for the majority (88.6%) of occurrences, although meningitis cases showed an increasing trend during the time period. The age group 85+ exhibited the highest incidence. The implementation of COVID-19 preventive interventions in 2020 resulted in a significant reduction in H. influenzae incidence, which returned to pre-COVID levels in 2021. A negative correlation was observed between monthly H. influenzae cases and outdoor temperature. An overall level of genetic beta-lactamase resistance of 26.3% was observed divided into 10.6% beta-lactamase-positive ampicillin-resistant (gBLPAR), 13.6% beta-lactamase-negative ampicillin-resistant (gBLNAR) and 2.1% beta-lactamase-positive amoxicillin clavulanate-resistant (gBLPACR). Other non-beta-lactam resistance traits were detected in 7.6% of isolates (primarily aminoglycoside-modifying enzymes). CONCLUSION The overall incidence of H. influenzae in Denmark returned to stable levels after the COVID-19 epidemic, with NTHi strains dominating. The COVID-19 preventive interventions led to a major reduction in incidence. A significant negative correlation between the incidence of H. influenzae and temperature was observed. The study revealed an overall genetic beta-lactam resistance rate of 26.3%, and the concordance between genotypic and phenotypic beta-lactam resistance was high (98.2%).
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Affiliation(s)
- Hans-Christian Slotved
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Thor Bech Johannesen
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Marc Stegger
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Tine Dalby
- Department of Infectious Disease Epidemiology & Prevention, Statens Serum Institut, Copenhagen, Denmark
| | - Kurt Fuursted
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
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Su PY, Cheng WH, Ho CH. Molecular characterization of multidrug-resistant non-typeable Haemophilus influenzae with high-level resistance to cefuroxime, levofloxacin, and trimethoprim-sulfamethoxazole. BMC Microbiol 2023; 23:178. [PMID: 37407940 DOI: 10.1186/s12866-023-02926-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023] Open
Abstract
BACKGROUND Non-typeable Haemophilus influenzae (NTHi) has become the major cause of invasive H. influenzae diseases in the post-H. influenzae type b vaccine era. The emergence of multidrug-resistant (MDR) NTHi is a growing public health problem. Herein, we investigated the molecular basis of MDR in NTHi. The isolated NTHi were subjected to antimicrobial susceptibility testing for 12 agents. Whole genome and plasmid sequencing were conducted and analyzed to identify significant genetic variations and plasmid-encoded genes conferred antibiotic resistance. RESULTS Thirteen (50%) MDR NTHi isolates were obtained; of these, 92.3% were non-susceptible to ampicillin, 30.8% to amoxicillin-clavulanate, 61.5% to cefuroxime, 61.5% to ciprofloxacin/levofloxacin, 92.3% to trimethoprim-sulfamethoxazole, 30.8% to tetracycline, and 7.7% to azithromycin. Eight ampicillin-resistant isolates were β-lactamase positive; of these, 6 carried blaTEM-1 and 2 carried blaROB-1, whereas 4 were β-lactamase negative. Genetic variations in mrdA, mepA, and pbpG were correlated with amoxicillin-clavulanate non-susceptibility, whereas variations in ftsI and lpoA conferred cefuroxime resistance. Five variations in gyrA, 2 in gyrB, 3 in parC, 1 in parE, and 1 in the parC-parE intergenic region were associated with levofloxacin/ciprofloxacin non-susceptibility. Among these genes, 8 variations were linked to high-level levofloxacin resistance. Six variations in folA were associated with trimethoprim-sulfamethoxazole resistance. Plasmid-bearing tet(B) and mef(A) genes were responsible for tetracycline and azithromycin resistance in 4 and 1 MDR isolates, respectively. CONCLUSIONS This study clarified the molecular epidemiology of MDR in NTHi. This can benefit the monitoring of drug resistance trends in NTHi and the adequate medical management of patients with NTHi infection.
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Affiliation(s)
- Pei-Yi Su
- Department of Laboratory Medicine, E-Da Hospital, Kaohsiung, Taiwan
| | - Wei-Hung Cheng
- Department of Parasitology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Cheng-Hsun Ho
- Department of Medical Laboratory Science, College of Medical Science and Technology, I-Shou University, No.8, Yida Road, Jiaosu Village, Yanchao District, Kaohsiung City, 82445, Taiwan.
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4
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Shariati A, Arshadi M, Khosrojerdi MA, Abedinzadeh M, Ganjalishahi M, Maleki A, Heidary M, Khoshnood S. The resistance mechanisms of bacteria against ciprofloxacin and new approaches for enhancing the efficacy of this antibiotic. Front Public Health 2022; 10:1025633. [PMID: 36620240 PMCID: PMC9815622 DOI: 10.3389/fpubh.2022.1025633] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022] Open
Abstract
For around three decades, the fluoroquinolone (FQ) antibiotic ciprofloxacin has been used to treat a range of diseases, including chronic otorrhea, endocarditis, lower respiratory tract, gastrointestinal, skin and soft tissue, and urinary tract infections. Ciprofloxacin's main mode of action is to stop DNA replication by blocking the A subunit of DNA gyrase and having an extra impact on the substances in cell walls. Available in intravenous and oral formulations, ciprofloxacin reaches therapeutic concentrations in the majority of tissues and bodily fluids with a low possibility for side effects. Despite the outstanding qualities of this antibiotic, Salmonella typhi, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa have all shown an increase in ciprofloxacin resistance over time. The rise of infections that are resistant to ciprofloxacin shows that new pharmacological synergisms and derivatives are required. To this end, ciprofloxacin may be more effective against the biofilm community of microorganisms and multi-drug resistant isolates when combined with a variety of antibacterial agents, such as antibiotics from various classes, nanoparticles, natural products, bacteriophages, and photodynamic therapy. This review focuses on the resistance mechanisms of bacteria against ciprofloxacin and new approaches for enhancing its efficacy.
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Affiliation(s)
- Aref Shariati
- Molecular and Medicine Research Center, Khomein University of Medical Sciences, Khomein, Iran
| | - Maniya Arshadi
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran,Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | | | - Mostafa Abedinzadeh
- Student Research Committee, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Mahsa Ganjalishahi
- Student Research Committee, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Abbas Maleki
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Mohsen Heidary
- Department of Laboratory Sciences, School of Paramedical Sciences, Sabzevar University of Medical Sciences, Sabzevar, Iran,Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran,*Correspondence: Mohsen Heidary
| | - Saeed Khoshnood
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran,Student Research Committee, Ilam University of Medical Sciences, Ilam, Iran,Saeed Khoshnood
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Carrera-Salinas A, González-Díaz A, Calatayud L, Mercado-Maza J, Puig C, Berbel D, Càmara J, Tubau F, Grau I, Domínguez MÁ, Ardanuy C, Martí S. Epidemiology and population structure of Haemophilus influenzae causing invasive disease. Microb Genom 2021; 7. [PMID: 34898424 PMCID: PMC8767337 DOI: 10.1099/mgen.0.000723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
This study provides an update on invasive Haemophilus influenzae disease in Bellvitge University Hospital (2014–2019), reporting its evolution from a previous period (2008–2013) and analysing the non-typeable H. influenzae (NTHi) population structure using a clade-related classification. Clinical data, antimicrobial susceptibility and serotyping were studied and compared with those of the previous period. Population structure was assessed by multilocus sequence typing (MLST), SNP-based phylogenetic analysis and clade-related classification. The incidence of invasive H. influenzae disease remained constant between the two periods (average 2.07 cases per 100 000 population), while the 30 day mortality rate decreased (20.7–14.7 %, respectively). Immunosuppressive therapy (40 %) and malignancy (36 %) were the most frequent comorbidities. Ampicillin and fluoroquinolone resistance rates had increased between the two periods (10–17.6 % and 0–4.4 %, respectively). NTHi was the main cause of invasive disease in both periods (84.3 and 85.3 %), followed by serotype f (12.9 and 8.8 %). NTHi displayed high genetic diversity. However, two clusters of 13 (n=20) and 5 sequence types (STs) (n=10) associated with clade V included NTHi strains of the most prevalent STs (ST3 and ST103), many of which showed increased frequency over time. Moreover, ST103 and ST160 from clade V were associated with β-lactam resistance. Invasive H. influenzae disease is uncommon, but can be severe, especially in the elderly with comorbidities. NTHi remains the main cause of invasive disease, with ST103 and ST160 (clade V) responsible for increasing β-lactam resistance over time.
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Affiliation(s)
- Anna Carrera-Salinas
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain
| | - Aida González-Díaz
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Laura Calatayud
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Julieta Mercado-Maza
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain
| | - Carmen Puig
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain
| | - Dàmaris Berbel
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Jordi Càmara
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Fe Tubau
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Imma Grau
- Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.,Infectious Diseases Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain
| | - M Ángeles Domínguez
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain.,Spanish Network for Research in Infectious Diseases (REIPI), ISCIII, Madrid, Spain.,Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
| | - Carmen Ardanuy
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.,Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
| | - Sara Martí
- Microbiology Department, Bellvitge University Hospital, IDIBELL-UB, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.,Department of Medicine, School of Medicine, University of Barcelona, Barcelona, Spain
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6
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Mizoi K, Wajima T, Tanaka E, Nakaminami H, Noguchi N. Comparison of the bactericidal effects of quinolones against low-susceptible Haemophilus influenzae. J Med Microbiol 2021; 70. [PMID: 34165425 DOI: 10.1099/jmm.0.001376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The increasing incidence of Haemophilus influenzae with decreased susceptibility to quinolones (quinolone low-susceptible H. influenzae) in Japan has raised concerns about therapeutic failure. Thus, assessment of effective antimicrobial agents is necessary to establish an effective therapeutic strategy against resulting infections. In this study, in vitro bactericidal effects of quinolones on low-susceptible H. influenzae strains were evaluated using time-kill curve analysis. For tosufloxacin, log reduction values for low-susceptible strains were significantly lower than those for susceptible strains at both Cmax and 1/2 Cmax. Conversely, although the log reduction values were lower for susceptible strains, the Cmax of levofloxacin and β-lactams (amoxicillin and cefditoren) indicated bactericidal effects. In addition, higher concentrations of tosufloxacin at 2×Cmax and 4×Cmax had bactericidal effects on not only susceptible but also low-susceptible strains. These data strongly suggest that we should consider the presence of low-susceptible strains and reconsider the appropriate dosage of tosufloxacin for treatment, especially for paediatric patients.
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Affiliation(s)
- Kosei Mizoi
- Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 1920392, Japan
| | - Takeaki Wajima
- Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 1920392, Japan.,Present address: Department of Microbiology, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku, Nagoya 468-8503, Japan
| | - Emi Tanaka
- Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 1920392, Japan
| | - Hidemasa Nakaminami
- Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 1920392, Japan
| | - Norihisa Noguchi
- Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 1920392, Japan
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Takeuchi N, Ohkusu M, Hoshino T, Yamamoto S, Segawa S, Murata S, Ishiwada N. Emergence of Haemophilus influenzae with low susceptibility to quinolones isolated from pediatric patients in Japan. J Infect Chemother 2021; 27:1020-1026. [PMID: 33658143 DOI: 10.1016/j.jiac.2021.02.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/21/2021] [Accepted: 02/17/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION In 2010, oral fluoroquinolone tosufloxacin (TFX) granules were released as the first oral respiratory quinolone for children in Japan. METHODS To investigate the recent trend of H. influenzae strains with low susceptibility to quinolones in children, we analyzed the gene sequences of quinolone resistance-determining regions (QRDRs) of gyrA, gyrB, parC, and parE of 23 clinical isolates from 15 patients aged <15 years with an MIC of ≥0.5 μg/mL for TFX from 2010 to 2018. RESULTS Amino acid substitutions were observed in both GyrA and ParC in 13 strains (81%, 13/16), except two strains with a TFX MIC of 0.5 μg/mL with amino acid substitution in only GyrA and one strain with a TFX MIC of 1 μg/mL with no amino acid substitution. Four ST422 strains were observed in 2018, the detection age range was wide (0-7 years), and the residential city was varied. A total of 3/15 patients had a clear history of TFX treatment. CONCLUSIONS Even for the strain with an MIC of 0.5 μg/mL for TFX, it is highly possible that it harbors a mutation in gyrA, which is the first step toward quinolone resistance, and it may also harbor mutations in both gyrA and parC. Furthermore, several specific sequence type quinolone-resistant H. influenzae strains, particularly ST422, may be widespread among children in Japan. It is necessary to investigate changes in resistance both at the MIC and gene levels. The continuous monitoring of strains and the use of antimicrobial drugs in treatment should be carefully observed.
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Affiliation(s)
- Noriko Takeuchi
- Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba, Japan.
| | - Misako Ohkusu
- Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Tadashi Hoshino
- Division of Infectious Diseases, Chiba Children's Hospital, Chiba, Japan
| | - Shota Yamamoto
- Division of Infectious Diseases, Chiba Children's Hospital, Chiba, Japan
| | - Shunsuke Segawa
- Division of Clinical Laboratory, Chiba University Hospital, Chiba, Japan
| | - Shota Murata
- Division of Clinical Laboratory, Chiba University Hospital, Chiba, Japan
| | - Naruhiko Ishiwada
- Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba, Japan
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8
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Tchatchouang S, Nzouankeu A, Hong E, Terrade A, Denizon M, Deghmane AE, Ndiang SMT, Pefura-Yone EW, Penlap Beng V, Njouom R, Fonkoua MC, Taha MK. Analysis of Haemophilus species in patients with respiratory tract infections in Yaoundé, Cameroon. Int J Infect Dis 2020; 100:12-20. [PMID: 32827751 DOI: 10.1016/j.ijid.2020.08.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/13/2020] [Accepted: 08/16/2020] [Indexed: 10/23/2022] Open
Abstract
OBJECTIVES To identifyHaemophilus species and characterize antimicrobial susceptibility of isolates from patients with respiratory tract infections (RTIs) in Cameroon. METHODS Isolates (n = 95) were from patients with RTIs obtained from two Hospitals in Yaoundé, Cameroon. Isolates were identified by biochemical assay, PCR-based method, MALDI-TOF and whole genome sequencing. Antibiotic minimum inhibitory concentrations were determined by E-test. RESULTS H. influenzae was the most prevalent species varying from 76.8% to 84.2% according to different methods. The isolates were mainly nontypable (n = 70, 96%). Three isolates of H. influenzae were capsulated (b, e and f). The isolates were genetically diverse and 40 unique sequence types were identified including 11 new ones. Resistance to ampicillin was observed among 55.3% (52/94) and 9% (14/52) produced TEM-1 β-lactamase. PBP3 mutations occurred in 57.7% of ampicillin resistant isolates (30/52). Eleven isolates were chloramphenicol resistant with 80% producing chloramphenicol acetyltransferase (8/10). Four Haemophilus isolates were rifampicin resistant with two mutations in rpoB gene. Five isolates were ciprofloxacin resistant and harbored mutations in the quinolone resistance determining regions of gyrA and parC genes. CONCLUSION H. influenzae isolates are highly diverse and show high levels of antibiotic resistance. H. influenzae serotype b is still circulating in the post-vaccination era.
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Affiliation(s)
- Serges Tchatchouang
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon; Department of Bacteriology, Centre Pasteur of Cameroon, Yaoundé, Cameroon; Department of Biochemistry, University of Yaoundé, Yaoundé, Cameroon; Invasive Bacterial Infections Unit, National Reference Centre for Meningococci and Haemophilus influenzae, Institut Pasteur, Paris, France
| | - Ariane Nzouankeu
- Department of Bacteriology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | - Eva Hong
- Invasive Bacterial Infections Unit, National Reference Centre for Meningococci and Haemophilus influenzae, Institut Pasteur, Paris, France
| | - Aude Terrade
- Invasive Bacterial Infections Unit, National Reference Centre for Meningococci and Haemophilus influenzae, Institut Pasteur, Paris, France
| | - Mélanie Denizon
- Invasive Bacterial Infections Unit, National Reference Centre for Meningococci and Haemophilus influenzae, Institut Pasteur, Paris, France
| | - Ala-Eddine Deghmane
- Invasive Bacterial Infections Unit, National Reference Centre for Meningococci and Haemophilus influenzae, Institut Pasteur, Paris, France
| | | | | | | | - Richard Njouom
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | | | - Muhamed-Kheir Taha
- Invasive Bacterial Infections Unit, National Reference Centre for Meningococci and Haemophilus influenzae, Institut Pasteur, Paris, France.
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9
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Wen S, Feng D, Chen D, Yang L, Xu Z. Molecular epidemiology and evolution of Haemophilus influenzae. INFECTION GENETICS AND EVOLUTION 2020; 80:104205. [DOI: 10.1016/j.meegid.2020.104205] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 10/25/2022]
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10
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Chang CM, Shih HI, Wu CJ, Lauderdale TL, Lee NY, Lee CC, Chen YC, Huang CC, Ko WC. Fluoroquinolone resistance in Haemophilus influenzae from nursing home residents in Taiwan: correlation of MICs and mutations in QRDRs. J Appl Microbiol 2020; 128:1624-1633. [PMID: 31951091 DOI: 10.1111/jam.14580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 11/28/2022]
Abstract
AIMS To study the association between number and positions of mutations with MICs of fluoroquinolone non-susceptible Haemophilus influenzae. METHODS AND RESULTS More than 40% of 48 H. influenzae isolated from nursing home residents were not susceptible to fluoroquinolone. Amino acid changes in the quinolone resistance determining regions, and correlation with MICs and inhibition zone diameters were analysed. All isolates with reduced susceptibility to fluoroquinolones (MIC ≥0·125 µg ml-1 ) had at least one mutation in gyrA at position 84 and were resistant to nalidixic acid. Compared to isolates with reduced susceptibility, resistant isolates were associated with mutations in gyrA at positions 88 and 134, and in parC at position 88 (P < 0·001). Inhibition zone diameter for nalidixic acid disk ≥23 mm may detect susceptible isolates. CONCLUSIONS Reduced susceptibility to fluoroquinolones was associated with mutations at position 84 in gyrA. A further increase in fluoroquinolone MIC was associated with mutations in gyrA at positions 88 and 134, and parC at position 88. SIGNIFICANCE AND IMPACT OF THE STUDY Due to limited resistant H. influenzae strains, prior studies on association between positions of mutations and fluoroquinolone MICs were inconclusive. The comparison of mutations between isolates with susceptibility, reduced susceptibility and high resistance supported the importance of the present study.
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Affiliation(s)
- C-M Chang
- Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.,Division of Geriatrics and Gerontology, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.,Center of Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan.,Department of Medicine, National Cheng Kung University Medical College, Tainan, Taiwan
| | - H-I Shih
- Department of Emergency Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
| | - C-J Wu
- Division of Infectious Diseases, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - T-L Lauderdale
- Division of Infectious Diseases, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - N-Y Lee
- Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.,Center of Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan
| | - C-C Lee
- Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.,Center of Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Y-C Chen
- Division of Infectious Diseases, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - C-C Huang
- Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.,Division of Geriatrics and Gerontology, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
| | - W-C Ko
- Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.,Center of Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan.,Department of Medicine, National Cheng Kung University Medical College, Tainan, Taiwan
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11
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In Vitro Derivation of Fluoroquinolone-Resistant Mutants from Multiple Lineages of Haemophilus influenzae and Identification of Mutations Associated with Fluoroquinolone Resistance. Antimicrob Agents Chemother 2020; 64:AAC.01500-19. [PMID: 31740553 DOI: 10.1128/aac.01500-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/10/2019] [Indexed: 12/21/2022] Open
Abstract
Haemophilus influenzae is a pathogenic bacterium that causes respiratory and otolaryngological infections. The increasing prevalence of β-lactamase-negative high-level ampicillin-resistant H. influenzae (high-BLNAR) is a clinical concern. Fluoroquinolones are alternative agents to β-lactams. However, the emergence and increasing prevalence of fluoroquinolone-resistant H. influenzae have been reported. The current risk of fluoroquinolone resistance in H. influenzae (especially in high-BLNAR) has not yet been evaluated. Here, we examined the development of fluoroquinolone resistance in fluoroquinolone-susceptible clinical H. influenzae isolates in vitro during passaging in the presence of moxifloxacin (from 0.03 to 128 mg/liter). Twenty-nine isolates were examined. Seventeen isolates (58.6%) showed reduced moxifloxacin susceptibility, and 10 of these 17 isolates (34.5% of all isolates) exceeded the Clinical and Laboratory Standards Institute breakpoint for moxifloxacin (MIC of >1 mg/liter) after repeat cultivation on moxifloxacin-containing agar. Seven of these ten isolates were high-BLNAR and represented multiple lineages. We identified 56 novel mutations in 45 genes induced during the development of fluoroquinolone resistance, except the defined quinolone resistance-determining regions (Ser84Leu and Asp88Tyr/Gly/Asn in GyrA and Gly82Asp, Ser84Arg, and Glu88Lys in ParC). Glu153Leu and ΔGlu606 in GyrA, Ser467Tyr and Glu469Asp in GyrB, and ompP2 mutations were novel mutations contributing to fluoroquinolone resistance in H. influenzae In conclusion, H. influenzae clinical isolates from multiple lineages can acquire fluoroquinolone resistance by multiple novel mutations. The higher rate of derivation of fluoroquinolone-resistant H. influenzae from high-BLNAR than β-lactamase-negative ampicillin-susceptible isolates (P = 0.01) raises the possibility of the emergence and spread of fluoroquinolone-resistant high-BLNAR in the clinical setting.
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12
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Sakata H, Watanabe A, Iwata S, Sato Y, Suzuki K, Miyashita N, Hori S, Yamaguchi Y, Odajima M, Katakuse Y, Hasegawa T, Maki N, Wada K. Surveillance on susceptibility of strains isolated from pediatric infections. J Infect Chemother 2018; 25:163-169. [PMID: 30600131 DOI: 10.1016/j.jiac.2018.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/18/2018] [Accepted: 11/05/2018] [Indexed: 10/27/2022]
Abstract
During the period from January to December 2015, 104 Streptococcus pneumoniae strains, 129 Haemophilus influenzae strains and 54 Moraxella catarrhalis strains isolated from clinical specimens of pediatric infections in the national 16 institutions, studied susceptibilities of total 28 antibiotics, the capsular serotype for S. pneumoniae, the capsular b type and β-lactamase production capability for H. influenzae, and the β-lactamase production capability for M. catarrhalis were measured. In S. pneumoniae, the results showed that 68 strains (65.4%) were PSSP, 32 (30.8%) were PISP, and 4 (3.8%) were PRSP. The susceptibilities of TBPM and GRNX among oral antibiotics, and PAPM among injectable antibiotics demonstrated the lowest value with MIC90 ≤ 0.06 μg/mL. The most frequent distribution of S. pneumoniae serotypes was seen in 15B, followed by 19A, and 35B. Serotype strains contained in 13-valent pneumococcal conjugate vaccine (PCV13) were 19 strains (18.3%). In H. influenzae, the results showed that BLNAS accounted for 40 strains (31.0%), BLNAI for 28 strains (21.7%), BLNAR for 47 strains (36.4%), β-lactamase producing for 14 strains (10.8%). The susceptibilities of quinolones demonstrated the lowest outcome among oral antibiotics with MIC90 ≤ 0.06 μg/mL, and CTRX and TAZ/PIPC (TAZ4 fixed) among injectable antibiotics with MIC of 0.25 μg/mL. There was no detection of capsular type b strains. In M. catarrhalis, all the isolates were β-lactamase producing strains. The susceptibilities of TBPM, CPFX, TFLX and GRNX among oral antibiotics, and TAZ/PIPC (TAZ4 fixed), PAPM, MEPM and DRPM among injectable antibiotics demonstrated the lowest outcome with MIC of ≤0.06 μg/mL.
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Affiliation(s)
- Hiroshi Sakata
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Akira Watanabe
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Satoshi Iwata
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan.
| | - Yoshitake Sato
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Kenji Suzuki
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Naoyuki Miyashita
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Seiji Hori
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Yoshio Yamaguchi
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Masaaki Odajima
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Yoshitaka Katakuse
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Toshikazu Hasegawa
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Nobuko Maki
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
| | - Koichi Wada
- The Promotion Committee for Proper Use of Pediatric Quinolones of Japanese Society of Chemotherapy, The Japanese Association for Infectious Diseases and the Japanese Society for Pediatric Infectious Diseases, Tokyo, Japan
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13
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Microbial virulence, molecular epidemiology and pathogenic factors of fluoroquinolone-resistant Haemophilus influenzae infections in Guangzhou, China. Ann Clin Microbiol Antimicrob 2018; 17:41. [PMID: 30470228 PMCID: PMC6251178 DOI: 10.1186/s12941-018-0290-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 10/09/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fluoroquinolone-resistant Haemophilus influenzae (FRHI) has been reported worldwide but remain unclear in China. METHODS A total of 402 H. influenzae isolates collected from 2016 to 2017 were included. Antimicrobial susceptibility on 10 antibiotics was performed, and minimum inhibitory concentration of ciprofloxacin- and nalidixic acid-resistant strains were further determined by E-test strips, with risk factors also evaluated. Strains with resistance or reduced susceptibility to ciprofloxacin were subjected to sequencing of the quinolone resistance-determining regions (QRDR) and plasmid-mediated quinolone resistance genes by sequencing, with multi-locus sequence typing. RESULTS 2.2% of H. influenzae strains were non-susceptible (7/402, 1.7%) or susceptible (2/402, 0.5%) to ciprofloxacin but NAL-resistant by E-test, and multidrug resistance was more common in fluoroquinolones non-susceptible H. influenzae group (p = 0.000). Infection risk factors included invasive procedure (p = 0.011), catching cold/previous contact with someone who had a cold (p = 0.019), fluoroquinolones use during previous 3 months (p = 0.003). With none of mutations obtained in gyrB, parE and other plasmid-mediated quinolone resistance genes, 7 and 4 strains were found for Ser-84-Leu substitutions in gyrA and one amino acid substitution in the QRDR of gyrA linked with one amino acid substitution in the QRDR of parC, respectively. In addition, five sequence types (ST) were identified, with ST1719 firstly found. CONCLUSIONS For the first time, this study has reported the incidence, risk factors, molecular determinants on fluoroquinolones resistance and ST of FRHI strains in mainland China, representing the first evidence of mutation of gyrA and parC in China and the new ST1719 worldwide.
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14
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Honda H, Sato T, Shinagawa M, Fukushima Y, Nakajima C, Suzuki Y, Shiraishi T, Kuronuma K, Takahashi S, Takahashi H, Yokota SI. Multiclonal Expansion and High Prevalence of β-Lactamase-Negative Haemophilus influenzae with High-Level Ampicillin Resistance in Japan and Susceptibility to Quinolones. Antimicrob Agents Chemother 2018; 62:e00851-18. [PMID: 29987153 PMCID: PMC6125502 DOI: 10.1128/aac.00851-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/29/2018] [Indexed: 12/11/2022] Open
Abstract
β-Lactam-resistant Haemophilus influenzae is a clinical concern. A high prevalence (>40%) of β-lactamase-negative high-level ampicillin-resistant H. influenzae (high-BLNAR) isolates in Japan has been reported. However, the reasons for the expansion are unknown. High-BLNAR strains possess an amino acid substitution, either Asn526Lys (group III) or Arg517His (group III-like) in addition to Ser385Thr, in penicillin-binding protein 3 (PBP3). To determine the current prevalence of high-BLNAR strains and the mechanisms behind their expansion in Japan, their prevalence, PBP3 types, multilocus sequence types, and susceptibilities to quinolones approved in Japan as alternatives were determined. Sixty percent of H. influenzae clinical isolates (62/104 isolates) were β-lactamase-negative ampicillin-resistant H. influenzae (BLNAR) strains. Among BLNAR isolates, 92% (57/62 isolates) were high-BLNAR strains. Most isolates were classified as belonging to group III, which contained many genotypes (11 PBP3 types and 25 sequence types). These results indicated that the expansion of high-BLNAR isolates was multiclonal and such strains are still predominant in Japanese clinical settings. One high-BLNAR isolate harbored the novel amino acid substitution Asn526Met in addition to Ser385Thr in PBP3, suggesting a new group (group IV). No quinolone-resistant H. influenzae isolates were identified. The MICs for the quinolones (moxifloxacin, garenoxacin, and tosufloxacin) were similar to that for levofloxacin, whereas sitafloxacin exhibited a lower MIC. However, we obtained 4 H. influenzae isolates with decreased quinolone susceptibility with the amino acid substitution Ser84Leu in GyrA, and 3 of those isolates were high-BLNAR isolates. In summary, this study shows that multiclonal high-BLNAR strains predominate in a Japanese university hospital. Isolates remain sensitive to quinolones, but vigilance is required to prevent the development of fluoroquinolone resistance in high-BLNAR strains.
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Affiliation(s)
- Hiroyuki Honda
- Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Toyotaka Sato
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Masaaki Shinagawa
- Division of Laboratory Medicine, Sapporo Medical University Hospital, Sapporo, Japan
| | - Yukari Fukushima
- Division of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan
| | - Chie Nakajima
- Division of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan
- Global Station for Zoonosis Control, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Yasuhiko Suzuki
- Division of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan
- Global Station for Zoonosis Control, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Tsukasa Shiraishi
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Koji Kuronuma
- Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Satoshi Takahashi
- Department of Infection Control and Laboratory Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Hiroki Takahashi
- Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Shin-Ichi Yokota
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
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15
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Cherkaoui A, Gaïa N, Baud D, Leo S, Fischer A, Ruppe E, François P, Schrenzel J. Molecular characterization of fluoroquinolones, macrolides, and imipenem resistance in Haemophilus influenzae: analysis of the mutations in QRDRs and assessment of the extent of the AcrAB-TolC-mediated resistance. Eur J Clin Microbiol Infect Dis 2018; 37:2201-2210. [PMID: 30145620 DOI: 10.1007/s10096-018-3362-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 08/15/2018] [Indexed: 11/25/2022]
Abstract
The aims of the present study were to characterize the mechanisms of resistance to fluoroquinolones, macrolides, and imipenem in Haemophilus influenzae, to assess the extent of the AcrAB-TolC-mediated resistance, and to define a core genome multilocus sequence typing (cgMLST) scheme for H. influenzae by using whole-genome sequencing. Four amino acid substitutions in GyrA (at Ser84 and Asp88), ParC (at Ser84), and ParE (at Asp420) were found to be closely associated to the MICs. We did not find any amino acid substitution surrounding the three highly conserved amino acid motifs in PBP3 related to imipenem resistance. All the isolates possessed the ermB gene. Carbonyl cyanide m-chlorophenylhydrazone (CCCP) decreased the MIC of imipenem by twofold for FQR-6 and fourfold for GE47 and GE88 strains. For erythromycin, the MICs were decreased by twofold. We found that the six FQR isolates were clustered in two groups. The number of different loci within FQR-1_FQR-3_FQR-5 cluster was 6, while FQR-2 and FQR-4 differed for 21 loci. FQR-1_FQR-3_FQR-5 and FQR-2_FQR-4 clusters were distant among each other and compared to 19 genomes downloaded from NCBI, to 8 strains heteroresistant to imipenem, and to 4 strains monoresistant to ciprofloxacin isolated in Denmark. We confirmed that specific amino acid substitutions in GyrA, ParC, and ParE are implicated in quinolone resistance. Additionally, the degree of resistance is related to the number of these amino acid substitutions. We provide robust evidence that drug efflux is one of the substantial mechanisms of imipenem and erythromycin resistance in H. influenzae.
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Affiliation(s)
- Abdessalam Cherkaoui
- Bacteriology Laboratory, Service of Laboratory Medicine, Department of Genetics, Laboratory Medicine and Pathology, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1205, Geneva, Switzerland.
| | - Nadia Gaïa
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1205, Geneva, Switzerland
| | - Damien Baud
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1205, Geneva, Switzerland
| | - Stefano Leo
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1205, Geneva, Switzerland
| | - Adrien Fischer
- Bacteriology Laboratory, Service of Laboratory Medicine, Department of Genetics, Laboratory Medicine and Pathology, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1205, Geneva, Switzerland
| | - Etienne Ruppe
- AP-HP, Hôpital Bichat, Laboratoire de Bactériologie, INSERM, IAME, UMR 1137, Université Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, 75018, Paris, France
| | - Patrice François
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1205, Geneva, Switzerland
| | - Jacques Schrenzel
- Bacteriology Laboratory, Service of Laboratory Medicine, Department of Genetics, Laboratory Medicine and Pathology, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1205, Geneva, Switzerland
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1205, Geneva, Switzerland
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16
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Hubbard ATM, Davies SEW, Baxter L, Thompson S, Collery MM, Hand DC, Thomas DJI, Fink CG. Comparison of the first whole genome sequence of 'Haemophilus quentini' with two new strains of 'Haemophilus quentini' and other species of Haemophilus. Genome 2018. [PMID: 29533728 DOI: 10.1139/gen-2017-0195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Comparison of the genome of the Gram negative human pathogen Haemophilus quentini MP1 with other species of Haemophilus revealed that, although it is more closely related to Haemophilus haemolyticus than Haemophilus influenzae, the pathogen is in fact genetically distinct, a finding confirmed by phylogenetic analysis using the H. influenzae multilocus sequence typing genes. Further comparison with two other H. quentini strains recently identified in Canada revealed that these three genomes are more closely related than any other species of Haemophilus; however, there is still some sequence variation. There was no evidence of acquired antimicrobial resistance within the H. quentini MP1 genome nor any mutations within the DNA gyrase or topoisomerase IV genes known to confer resistance to fluoroquinolones, which has been previously identified in other H. quentini isolates. We hope by presenting the annotation and genetic comparison of the H. quentini MP1 genome it will aid the future molecular detection of this potentially emerging pathogen via the identification of unique genes that differentiate it from other species of Haemophilus.
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Affiliation(s)
- Alasdair T M Hubbard
- a Micropathology Ltd., University of Warwick Science Park, Coventry, United Kingdom
| | - Sian E W Davies
- a Micropathology Ltd., University of Warwick Science Park, Coventry, United Kingdom
| | - Laura Baxter
- b School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Sarah Thompson
- c Microbiology Department, Sheffield Teaching Hospitals NHS Foundation Trust, Northern General Hospital, Sheffield, United Kingdom
| | - Mark M Collery
- a Micropathology Ltd., University of Warwick Science Park, Coventry, United Kingdom
| | - Daniel C Hand
- a Micropathology Ltd., University of Warwick Science Park, Coventry, United Kingdom
| | - D John I Thomas
- a Micropathology Ltd., University of Warwick Science Park, Coventry, United Kingdom
| | - Colin G Fink
- a Micropathology Ltd., University of Warwick Science Park, Coventry, United Kingdom
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17
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Kondo H, Ito S, Hatazaki K, Horie K, Nakane K, Mizutani K, Tsuchiya T, Yasuda M, Yokoi S, Nakano M, Deguchi T. GyrA and/or ParC alterations of Haemophilus influenzae strains isolated from the urethra of men with acute urethritis. J Infect Chemother 2017; 24:232-235. [PMID: 29138021 DOI: 10.1016/j.jiac.2017.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/21/2017] [Accepted: 10/12/2017] [Indexed: 11/25/2022]
Abstract
Of 73 clinical strains of Haemophilus influenzae isolated from the urethra of men with urogenital infections, we enrolled 6 strains (8.2%) with levofloxacin (LVFX) minimum inhibitory concentrations (MICs) of ≥0.03 μg/ml in this study. All the strains were isolated from non-gonococcal urethritis (NGU). We amplified the quinolone resistance-determining region of the gyrA gene and the analogous region of the parC gene from bacterial DNAs by PCR and sequenced the PCR products. Two strains with a LVFX MIC of 0.03 μg/ml had an amino acid change of Asp88 to Gly in GyrA. One with a LVFX MIC of 0.06 μg/ml had a change of Asp88 to Tyr in GyrA. Two with respective LVFX MICs of 0.12 and 0.25 μg/ml had a change of Ser84 to Leu in GyrA. One with a LVFX MIC of 1 μg/ml had changes of Ser84 to Leu in GyrA and of Ser84 to Ile in ParC. Multilocus sequence typing showed two strains with a change of Asp88 to Gly in GyrA had the same sequence type, but the others had sequence types different from each other. Single amino acid changes in GyrA alone or single changes in both GyrA and ParC could contribute to decreased susceptibility to fluoroquinolones in H. influenzae isolates from NGU. Most of the isolates with GyrA and/or ParC alterations would be multiclonal. The prevalence of such isolates would be relatively low, and they would still be susceptible to fluoroquinolones commonly prescribed for treatment of NGU.
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Affiliation(s)
- Hiromi Kondo
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Shin Ito
- iClinic, 5-9-6 Naga-machi, Taihaku-ku, Sendai, Miyagi 982-0011, Japan
| | - Kyoko Hatazaki
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Kengo Horie
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Keita Nakane
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Kosuke Mizutani
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Tomohiro Tsuchiya
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Mitsuru Yasuda
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Shigeaki Yokoi
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Masahiro Nakano
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan
| | - Takashi Deguchi
- Department of Urology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan.
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18
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Amino Acid Substitution in the Major Multidrug Efflux Transporter Protein AcrB Contributes to Low Susceptibility to Azithromycin in Haemophilus influenzae. Antimicrob Agents Chemother 2017; 61:AAC.01337-17. [PMID: 28848006 DOI: 10.1128/aac.01337-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/10/2017] [Indexed: 11/20/2022] Open
Abstract
Clarithromycin-resistant Haemophilus influenzae strains with a nonsense mutation in acrR generally exhibited susceptibility to azithromycin, although one strain was found to be nonsusceptible; we aimed to clarify the differences. This strain had an amino acid substitution, Arg327Ser, in AcrB. Introduction of this substitution into H. influenzae Rd caused an increase in the MIC of azithromycin, suggesting that this substitution contributed to nonsusceptibility. These findings indicate that azithromycin-nonsusceptible isolates could occur through stepwise mutation in the acr region.
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19
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López-Hernández I, Machuca J, Díaz de Alba P, Sarvisé C, Gómez F, Rodríguez-Martínez JM, Pascual A. Molecular Characterization of Fluoroquinolone-Resistant Haemophilus parainfluenzae Clinical Isolates in Spain. Microb Drug Resist 2017; 23:935-939. [PMID: 28414572 DOI: 10.1089/mdr.2016.0186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE The objective was to characterize a group of clinical isolates of fluoroquinolone-resistant Haemophilus parainfluenzae collected in Northern Spain (March-December 2014). METHODS Twelve clinical isolates of H. parainfluenzae were studied by performing antimicrobial susceptibility testing and PCR amplification and nucleotide sequencing of the QRDR (quinolone resistance-determining region) of gyrA, parC, gyrB, and parE genes. Screening for plasmid-mediated quinolone resistance (PMQR) was also studied. Pulsed-field gel electrophoresis (PFGE) was used for molecular typing. RESULTS Antimicrobial susceptibility testing showed that all the isolates were resistant to the fluoroquinolones tested (ciprofloxacin, levofloxacin, norfloxacin, and moxifloxacin). Analysis of the QRDR demonstrated that all the isolates presented mutations in gyrA and parC. A Glu88Lys substitution in ParC is reported for the first time in H. parainfluenzae. No PMQR gene was detected. PFGE results showed that isolates were not clonally related. CONCLUSION Multiple H. parainfluenzae fluoroquinolone-resistant isolates grouped in the same area in a short period of time showed diverse substitutions in QRDR of gyrA/parC and were not clonally related, indicating individual emergence. In addition, we described the first report of Glu88Lys substitution in ParC.
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Affiliation(s)
- Inmaculada López-Hernández
- 1 Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena , Seville, Spain
| | - Jesús Machuca
- 1 Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena , Seville, Spain
| | - Paula Díaz de Alba
- 1 Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena , Seville, Spain
| | - Carolina Sarvisé
- 2 Microbiology Unit, University Hospital Joan XXIII , Tarragona, Spain
| | - Frederic Gómez
- 2 Microbiology Unit, University Hospital Joan XXIII , Tarragona, Spain
| | | | - Alvaro Pascual
- 1 Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena , Seville, Spain .,3 Department of Microbiology, University of Seville , Seville, Spain
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Rise in Haemophilus influenzae With Reduced Quinolone Susceptibility and Development of a Simple Screening Method. Pediatr Infect Dis J 2017; 36:263-266. [PMID: 27870809 DOI: 10.1097/inf.0000000000001415] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND β-Lactamase-nonproducing ampicillin-resistant Haemophilus influenzae are prevalent in Japan. Resistance has increased as a consequence of the expanded use of antimicrobial agents, raising concerns about the rise of multidrug (macrolide and fluoroquinolone)-resistant H. influenzae. METHODS In this study, we investigated susceptibility to fluoroquinolones in H. influenzae clinical isolates from 2013 to 2014 and identified the amino acid substitutions in quinolone resistance-determining regions of gyrA and parC. RESULTS All isolates (n = 145) were susceptible to fluoroquinolones; however, some showed reduced susceptibility. The minimum inhibitory concentration of levofloxacin for these strains was 0.063-0.5 µg/mL, and the strains harbored the amino acid substitution S84L in GyrA. Such strains have seen a significant increase. Importantly, all mutants from 2014 were isolated from pediatric patients. In addition, we developed a simple polymerase chain reaction-based screening method for detecting isolates with reduced fluoroquinolone susceptibility. CONCLUSIONS The mutation in GyrA is important as a first step in the development of fluoroquinolone resistance. Hence, detection of reduced susceptible strains may influence the choice of antimicrobial treatment.
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Fuursted K, Hartmeyer GN, Stegger M, Andersen PS, Justesen US. Molecular characterisation of the clonal emergence of high-level ciprofloxacin-monoresistant Haemophilus influenzae in the Region of Southern Denmark. J Glob Antimicrob Resist 2016; 5:67-70. [PMID: 27436470 DOI: 10.1016/j.jgar.2015.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 12/09/2015] [Accepted: 12/19/2015] [Indexed: 11/15/2022] Open
Abstract
Haemophilus influenzae is an important human pathogen usually susceptible to quinolones. Here we report the emergence of high-level ciprofloxacin-monoresistant H. influenzae in the Region of Southern Denmark. Four isolates were collected for phenotypic and molecular characterisation using whole-genome sequencing (WGS). During an 18-month period, the occurrence of high-level ciprofloxacin-monoresistant H. influenzae in patients aged 1-77 years from sputum, ear and eye samples was detected. An epidemiological link between the patients could not be identified. The isolates were non-encapsulated, biotype III and were demonstrated by WGS to be clonal belonging to a single clade with an unknown multilocus sequence type (double-locus variant of ST196). The antibiogram demonstrated that they were all monoresistant to ciprofloxacin with a minimum inhibitory concentration (MIC) >32mg/L. In silico resistome analysis revealed identical, both previously characterised and novel, putative resistance-related mutations in gyrA (S84L and D88N), parC (K20R, S84I, D356A or T356A, and M481I) and parE (E151K, I159A, D420N and S599A) in all isolates. The isolates were otherwise negative for any resistance genes. This is the first description of the clonal emergence of high-level monoresistant H. influenzae due to amino acid substitutions in gyrA, parC and parE.
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Affiliation(s)
- Kurt Fuursted
- Department of Microbiology & Infection Control, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
| | - Gitte Nyvang Hartmeyer
- Department of Clinical Microbiology, Odense University Hospital, DK-5000 Odense C, Denmark
| | - Marc Stegger
- Department of Microbiology & Infection Control, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark
| | - Paal Skytt Andersen
- Department of Microbiology & Infection Control, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark
| | - Ulrik Stenz Justesen
- Department of Clinical Microbiology, Odense University Hospital, DK-5000 Odense C, Denmark
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Marti S, Puig C, de la Campa AG, Tirado-Velez JM, Tubau F, Domenech A, Calatayud L, Garcia-Somoza D, Ayats J, Liñares J, Ardanuy C. Identification of Haemophilus haemolyticus in clinical samples and characterization of their mechanisms of antimicrobial resistance. J Antimicrob Chemother 2015; 71:80-4. [PMID: 26472767 DOI: 10.1093/jac/dkv307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/28/2015] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The objectives of this study were to establish the frequency of Haemophilus haemolyticus in clinical samples, to determine the antimicrobial resistance rate and to identify the mechanisms of resistance to β-lactams and quinolones. METHODS An updated database was used to differentiate between MALDI-TOF MS results for Haemophilus influenzae and H. haemolyticus. Antimicrobial susceptibility was studied by microdilution, following EUCAST criteria. The β-lactamase types were identified by PCR analysis of isolates that tested positive for nitrocefin hydrolysis. Mutations in the ftsI gene were identified in isolates with ampicillin MICs ≥0.25 mg/L. Mutations in the quinolone resistance-determining region (QRDR) were identified in isolates with ciprofloxacin MICs ≥0.5 mg/L. RESULTS Overall, we identified 69 H. haemolyticus isolates from 1706 clinical isolates of Haemophilus spp. from respiratory, genital, invasive, and other infection sources. The frequency of H. haemolyticus was low in respiratory samples compared with that of H. influenzae, but in genital-related samples, the frequency was similar to that of H. influenzae. We found low antimicrobial resistance rates among H. haemolyticus isolates, with 8.7% for ampicillin, 8.7% for co-trimoxazole, 7.2% for tetracycline and 4.3% for ciprofloxacin. Mutations in the ftsI gene classified the isolates into four groups, including the newly described Group Hhae IV, which presents mutations in the ftsI gene not identified in H. influenzae and H. haemolyticus type strains. Three ciprofloxacin-resistant H. haemolyticus isolates with mutations affecting GyrA and ParC were identified. CONCLUSIONS The frequency of H. haemolyticus was low, especially in respiratory samples, where H. influenzae is the main pathogen of this genus. Although antimicrobial resistance rates were low, three ciprofloxacin-resistant H. haemolyticus clinical isolates have been identified for the first time.
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Affiliation(s)
- Sara Marti
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Puig
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
| | - Adela G de la Campa
- CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - José Manuel Tirado-Velez
- CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - Fe Tubau
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
| | - Arnau Domenech
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
| | - Laura Calatayud
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
| | - Dolors Garcia-Somoza
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
| | - Josefina Ayats
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
| | - Josefina Liñares
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Ardanuy
- Microbiology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona-IDIBELL, Barcelona, Spain CIBER de Enfermedades Respiratorias (CIBERes), Instituto de Salud Carlos III, Madrid, Spain
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Molecular characterization of fluoroquinolone resistance in nontypeable Haemophilus influenzae clinical isolates. Antimicrob Agents Chemother 2014; 59:461-6. [PMID: 25385097 DOI: 10.1128/aac.04005-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a common cause of respiratory infections in adults, who are frequently treated with fluoroquinolones. The aims of this study were to characterize the genotypes of fluoroquinolone-resistant NTHi isolates and their mechanisms of resistance. Among 7,267 H. influenzae isolates collected from adult patients from 2000 to 2013, 28 (0.39%) were ciprofloxacin resistant according to Clinical and Laboratory Standards Institute (CLSI) criteria. In addition, a nalidixic acid screening during 2010 to 2013 detected five (0.23%) isolates that were ciprofloxacin susceptible but nalidixic acid resistant. Sequencing of their quinolone resistance-determining regions and genotyping by pulse-field gel electrophoresis and multilocus sequence typing of the 25 ciprofloxacin-resistant isolates available and all 5 nalidixic acid-resistant isolates were performed. In the NTHi isolates studied, two mutations producing changes in two GyrA residues (Ser84, Asp88) and/or two ParC residues (Ser84, Glu88) were associated with increased fluoroquinolone MICs. Strains with one or two mutations (n = 15) had ciprofloxacin and levofloxacin MICs of 0.12 to 2 μg/ml, while those with three or more mutations (n = 15) had MICs of 4 to 16 μg/ml. Long persistence of fluoroquinolone-resistant strains was observed in three chronic obstructive pulmonary disease patients. High genetic diversity was observed among fluoroquinolone-resistant NTHi isolates. Although fluoroquinolones are commonly used to treat respiratory infections, the proportion of resistant NTHi isolates remains low. The nalidixic acid disk test is useful for detecting the first changes in GyrA or in GyrA plus ParC among fluoroquinolone-susceptible strains that are at a potential risk for the development of resistance under selective pressure by fluoroquinolone treatment.
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