Hajime Kanamori

Dr. Hajime Kanamori

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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 May 2017 in Clinical Infectious Diseases
Verified
Journal Article
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PDF file
HKHajime Kanamori
Hajime Kanamori
WRWilliam A Rutala
William A Rutala
DWDavid J Weber
David J Weber
Patient-care items can serve as a source or reservoir for healthcare-associated pathogens in hospitals. We reviewed healthcare- associated outbreaks from medical equipment and provide infection prevention recommendations. Multiple healthcare-associated outbreaks via a contaminated patient-care item were identified, including infections with multidrug-resistant organisms. The type of patient care items implicated as a fomite causing healthcare-associated infections (HAIs) has changed over time. Patient populations at risk were most commonly critically ill patients in adult and neonatal intensive care units. Most fomite related healthcare-associated outbreaks were due to inappropriate disinfection practices. Repeated healthcare-associated outbreaks via medical equipment highlight the need for infectious disease professionals to understand that fomites/medical devices may be a source of HAIs. The introduction of new and more complex medical devices will likely increase the risk that such devices serve as a source of HAIs. Assuring appropriate cleaning and disinfection or sterilization of medical equipment is necessary to prevent future fomite-associated outbreaks.

1 August 2017 in Antimicrobial Agents and Chemotherapy
Verified
Journal Article
Open access
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HKHajime Kanamori
Hajime Kanamori
CPChristian M. Parobek
Christian M. Parobek
JJJonathan J. Juliano
Jonathan J. Juliano
JJJames R. Johnson
James R. Johnson
BJBrian D. Johnston
Brian D. Johnston
DADeverick J. Anderson
Deverick J. Anderson
Escherichia coli sequence type 131 (ST131) predominates globally among multidrug-resistant (MDR) E. coli strains. We used whole-genome sequencing (WGS) to investigate 63 MDR E. coli isolates from 7 North Carolina community hospitals (2010 to 2015). Of these, 39 (62%) represented ST131, including 37 (95%) from the ST131- H 30R subclone: 10 (27%) from its H 30R1 subset and 27 (69%) from its H 30Rx subset. ST131 core genomes differed by a median of 15 (range, 0 to 490) single-nucleotide variants (SNVs) overall versus only 7 within H 30R1 (range, 3 to 12 SNVs) and 11 within H 30Rx (range, 0 to 21). The four isolates with identical core genomes were all H 30Rx. Epidemiological and clinical characteristics did not vary significantly by strain type, but many patients with MDR E. coli or H 30Rx infection were critically ill and had poor outcomes. H 30Rx isolates characteristically exhibited fluoroquinolone resistance and CTX-M-15 production, had a high prevalence of trimethoprim-sulfamethoxazole resistance (89%), sul1 (89%), and dfrA17 (85%), and were enriched for specific virulence traits, and all qualified as extraintestinal pathogenic E. coli . The high overall prevalence of CTX-M-15 appeared to be possibly attributable to its association with the ST131- H 30Rx subclone and IncF[F2:A1:B−] plasmids. Some phylogenetically clustered non-ST131 MDR E. coli isolates also had distinctive serotypes/ fimH types, fluoroquinolone mutations, CTX-M variants, and IncF types. Thus, WGS analysis of our community hospital source MDR E. coli isolates suggested ongoing circulation and differentiation of E. coli ST131 subclones, with clonal segregation of CTX-M variants, other resistance genes, Inc-type plasmids, and virulence genes.

6 July 2011 in Journal of Antimicrobial Chemotherapy
Verified
Journal Article
Open access
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HKHajime Kanamori
Hajime Kanamori
HYHisakazu Yano
Hisakazu Yano
YHYoichi Hirakata
Yoichi Hirakata
SEShiro Endo
Shiro Endo
KAKazuaki Arai
Kazuaki Arai
MKMitsuo Kaku
Mitsuo Kaku
Extended-spectrum β-lactamases (ESBLs) have become a problem among AmpC-producing Enterobacteriaceae and the emergence of concomitant quinolone resistance in β-lactamase-producing isolates poses a global threat. In this study we investigated the prevalence and regional variation of ESBLs in Japanese clinical isolates of Citrobacter spp. and analysed plasmid-mediated quinolone resistance (PMQR) determinants in ESBL-producing Citrobacter spp. A total of 348 clinical isolates of Citrobacter spp. collected throughout Japan were studied. Screening and the boronic acid disc test were performed to detect ESBLs in Citrobacter spp. with chromosomal AmpC β-lactamases. PCR and sequencing were done to identify ESBL and PMQR genes. For ESBL-producing Citrobacter spp., PFGE was performed using the SfiI restriction enzyme. The number of ESBL-producing isolates confirmed phenotypically was 67 (19.3%). The prevalence of ESBL-producing Citrobacter koseri was significantly higher (32.1%) than that of ESBL-producing Citrobacter freundii (4.6%) (P < 0.01). Moreover, the prevalence of ESBLs was notably higher among C. koseri from southern Japan (60.0%). CTX-M-2 was predominant in C. koseri. Of the ESBL-producing C. koseri analysed, 23.2% possessed PMQR determinants, and there was a significant association between qnrB4 and blaSHV-12. The 57 ESBL-producing Citrobacter spp. possessing blaCTX-M, blaSHV or blaTEM were divided into 18 unique PFGE types. This is the first report about the prevalence of PMQR determinants among ESBL-producing Citrobacter spp. from Japan. Our data suggest that ESBLs and PMQR determinants are spreading among C. koseri in Japan.

28 September 2020 in Clinical Infectious Diseases
Verified
Journal Article
Closed access
HKHajime Kanamori
Hajime Kanamori
DWDavid J Weber
David J Weber
WRWilliam A Rutala
William A Rutala
The healthcare environment serves as one of the possible routes of transmission of epidemiologically important pathogens, but the role of the contaminated environment on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission remains unclear. We reviewed survival, contamination, and transmission of SARS-CoV-2 via environmental surfaces and shared medical devices as well as environmental disinfection of SARS-CoV-2 in healthcare settings. Coronaviruses, including SARS-CoV-2, have been demonstrated to survive for hours to days on environmental surfaces depending on experimental conditions. The healthcare environment is frequently contaminated with SARS-CoV-2 RNA in most studies but without evidence of viable virus. Although direct exposure to respiratory droplets is the main transmission route of SARS-CoV-2, the contaminated healthcare environment can potentially result in transmission of SARS-CoV-2 as described with other coronaviruses such as SARS and Middle East respiratory syndrome coronaviruses. It is important to improve thoroughness of cleaning/disinfection practices in healthcare facilities and select effective disinfectants to decontaminate inanimate surfaces and shared patient care items.

24 August 2023 in mSphere
Verified
Journal Article
Open access
HBHiroaki Baba
Hiroaki Baba
MKMakoto Kuroda
Makoto Kuroda
TSTsuyoshi Sekizuka
Tsuyoshi Sekizuka
HKHajime Kanamori
Hajime Kanamori
Wastewater can be useful in monitoring the spread of antimicrobial resistance (AMR) within a hospital. The abundance of antibiotic resistance genes (ARGs) in hospital effluent was assessed using metagenomic sequencing (mDNA-seq) and hybrid capture (xHYB). mDNA-seq analysis and subsequent xHYB targeted enrichment were conducted on two effluent samples per month from November 2018 to May 2021. Reads per kilobase per million (RPKM) values were calculated for all 1,272 ARGs in the constructed database. The monthly numbers of patients with presumed extended-spectrum β-lactamase (ESBL)-producing and metallo-β-lactamase (MBL)-producing bacteria, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant enterococci (VRE) were compared with the monthly RPKM values of bla CTX-M , bla IMP , mecA , vanA , and vanB by xHYB. The average RPKM value for all ARGs detected by xHYB was significantly higher than that of mDNA-seq (665, 225, and 328, respectively, and P < 0.05). The average number of patients with ESBL producers and RPKM values of bla CTX-M-1 genes in 2020 were significantly higher than that in 2019 (17 and 13 patients per month and 921 vs 232 per month, respectively, both P < 0.05). The average numbers of patients with MBL-producers, MRSA, and VRE were 1, 28, and 0 per month, respectively, while the average RPKM values of bla IMP , mecA , vanA , and vanB were 6,163, 6, 0, and 126 per month, respectively. Monitoring ARGs in hospital effluent using xHYB was found to be more useful than conventional mDNA-seq in detecting ARGs including bla CTX-M , bla IMP, and vanB , which are important for infection control. IMPORTANCE: Environmental ARGs play a crucial role in the emergence and spread of AMR that constitutes a significant global health threat. One major source of ARGs is effluent from healthcare facilities, where patients are frequently administered antimicrobials. Culture-independent methods, including metagenomics, can detect environmental ARGs carried by non-culturable bacteria and extracellular ARGs. mDNA-seq is one of the most comprehensive methods for environmental ARG surveillance; however, its sensitivity is insufficient for wastewater surveillance. This study demonstrates that xHYB appropriately monitors ARGs in hospital effluent for sensitive identification of nosocomial AMR dissemination. Correlations were observed between the numbers of inpatients with antibiotic-resistant bacteria and the ARG RPKM values in hospital effluent over time. ARG surveillance in hospital effluent using the highly sensitive and specific xHYB method could improve our understanding of the emergence and spread of AMR within a hospital.

24 June 2022 in Antibiotics
Verified
Journal Article
Open access
PDF file
HBHiroaki Baba
Hiroaki Baba
MNMasateru Nishiyama
Masateru Nishiyama
Toru WatanabeToru Watanabe
Toru Watanabe
HKHajime Kanamori
Hajime Kanamori
Antimicrobial resistance (AMR) circulates through humans, animals, and the environments, requiring a One Health approach. Recently, urban sewage has increasingly been suggested as a hotspot for AMR even in high-income countries (HICs), where the water sanitation and hygiene infrastructure are well-developed. To understand the current status of AMR in wastewater in a HIC, we reviewed the epidemiological studies on AMR in the sewage environment in Japan from the published literature. Our review showed that a wide variety of clinically important antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antimicrobial residues are present in human wastewater in Japan. Their concentrations are lower than in low- and middle-income countries (LMICs) and are further reduced by sewage treatment plants (STPs) before discharge. Nevertheless, the remaining ARB and ARGs could be an important source of AMR contamination in river water. Furthermore, hospital effluence may be an important reservoir of clinically important ARB. The high concentration of antimicrobial agents commonly prescribed in Japan may contribute to the selection and dissemination of AMR within wastewater. Our review shows the importance of both monitoring for AMR and antimicrobials in human wastewater and efforts to reduce their contamination load in wastewater.