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Mechanisms, molecular and sero-epidemiology of antimicrobial resistance in bacterial respiratory pathogens isolated from Japanese children.

Abstract

BACKGROUND

The clinical management of community-acquired respiratory tract infections (RTIs) is complicated by the increasing worldwide prevalence of antibacterial resistance, in particular, beta-lactam and macrolide resistance, among the most common causative bacterial pathogens. This study aimed to determine the mechanisms and molecular- and sero-epidemiology of antibacterial resistance among the key paediatric respiratory pathogens in Japan.

METHODS

Isolates were collected at 18 centres in Japan during 2002 and 2003 from children with RTIs as part of the PROTEKT surveillance programme. A proportion of Haemophilus influenzae isolates was subjected to sequencing analysis of the ftsI gene; phylogenetic relatedness was assessed using multilocus sequence typing. Streptococcus pneumoniae isolates were screened for macrolide-resistance genotype by polymerase chain reaction and serotyped using the capsular swelling method. Susceptibility of isolates to selected antibacterials was performed using CLSI methodology.

RESULTS AND DISCUSSION

Of the 557 H. influenzae isolates collected, 30 (5.4%) were beta-lactamase-positive [BL+], 115 (20.6%) were BL-nonproducing ampicillin-resistant (BLNAR; MIC >or= 4 mg/L) and 79 (14.2%) were BL-nonproducing ampicillin-intermediate (BLNAI; MIC 2 mg/L). Dabernat Group III penicillin binding protein 3 (PBP3) amino acid substitutions in the ftsI gene were closely correlated with BLNAR status but phylogenetic analysis indicated marked clonal diversity. PBP mutations were also found among BL+ and BL-nonproducing ampicillin-sensitive isolates. Of the antibacterials tested, azithromycin and telithromycin were the most active against H. influenzae (100% and 99.3% susceptibility, respectively). A large proportion (75.2%) of the 468 S. pneumoniae isolates exhibited macrolide resistance (erythromycin MIC >or= 1 mg/L); erm(B) was the most common macrolide resistance genotype (58.8%), followed by mef(A) (37.2%). The most common pneumococcal serotypes were 6B (19.7%), 19F (13.7%), 23F (13.5%) and 6A (12.8%). Telithromycin and amoxicillin-clavulanate were the most active antibacterials against S. pneumoniae (99.8% and 99.6% susceptibility, respectively).

CONCLUSION

Approximately one-third of H. influenzae isolates from paediatric patients in Japan are BLNAI/BLNAR, mainly as a result of clonally diverse PBP3 mutations. Together with the continued high prevalence of pneumococcal macrolide resistance, these results may have implications for the clinical management of paediatric RTIs in Japan.

Authors+Show Affiliations

School of Medicine, Kitasato University, Kanagawa, Japan. sunakawa@med.kitasato-u.ac.jpNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17697316

Citation

Sunakawa, Keisuke, and David J. Farrell. "Mechanisms, Molecular and Sero-epidemiology of Antimicrobial Resistance in Bacterial Respiratory Pathogens Isolated From Japanese Children." Annals of Clinical Microbiology and Antimicrobials, vol. 6, 2007, p. 7.
Sunakawa K, Farrell DJ. Mechanisms, molecular and sero-epidemiology of antimicrobial resistance in bacterial respiratory pathogens isolated from Japanese children. Ann Clin Microbiol Antimicrob. 2007;6:7.
Sunakawa, K., & Farrell, D. J. (2007). Mechanisms, molecular and sero-epidemiology of antimicrobial resistance in bacterial respiratory pathogens isolated from Japanese children. Annals of Clinical Microbiology and Antimicrobials, 6, p. 7.
Sunakawa K, Farrell DJ. Mechanisms, Molecular and Sero-epidemiology of Antimicrobial Resistance in Bacterial Respiratory Pathogens Isolated From Japanese Children. Ann Clin Microbiol Antimicrob. 2007 Aug 13;6:7. PubMed PMID: 17697316.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mechanisms, molecular and sero-epidemiology of antimicrobial resistance in bacterial respiratory pathogens isolated from Japanese children. AU - Sunakawa,Keisuke, AU - Farrell,David J, Y1 - 2007/08/13/ PY - 2007/02/08/received PY - 2007/08/13/accepted PY - 2007/8/19/pubmed PY - 2007/11/2/medline PY - 2007/8/19/entrez SP - 7 EP - 7 JF - Annals of clinical microbiology and antimicrobials JO - Ann. Clin. Microbiol. Antimicrob. VL - 6 N2 - BACKGROUND: The clinical management of community-acquired respiratory tract infections (RTIs) is complicated by the increasing worldwide prevalence of antibacterial resistance, in particular, beta-lactam and macrolide resistance, among the most common causative bacterial pathogens. This study aimed to determine the mechanisms and molecular- and sero-epidemiology of antibacterial resistance among the key paediatric respiratory pathogens in Japan. METHODS: Isolates were collected at 18 centres in Japan during 2002 and 2003 from children with RTIs as part of the PROTEKT surveillance programme. A proportion of Haemophilus influenzae isolates was subjected to sequencing analysis of the ftsI gene; phylogenetic relatedness was assessed using multilocus sequence typing. Streptococcus pneumoniae isolates were screened for macrolide-resistance genotype by polymerase chain reaction and serotyped using the capsular swelling method. Susceptibility of isolates to selected antibacterials was performed using CLSI methodology. RESULTS AND DISCUSSION: Of the 557 H. influenzae isolates collected, 30 (5.4%) were beta-lactamase-positive [BL+], 115 (20.6%) were BL-nonproducing ampicillin-resistant (BLNAR; MIC >or= 4 mg/L) and 79 (14.2%) were BL-nonproducing ampicillin-intermediate (BLNAI; MIC 2 mg/L). Dabernat Group III penicillin binding protein 3 (PBP3) amino acid substitutions in the ftsI gene were closely correlated with BLNAR status but phylogenetic analysis indicated marked clonal diversity. PBP mutations were also found among BL+ and BL-nonproducing ampicillin-sensitive isolates. Of the antibacterials tested, azithromycin and telithromycin were the most active against H. influenzae (100% and 99.3% susceptibility, respectively). A large proportion (75.2%) of the 468 S. pneumoniae isolates exhibited macrolide resistance (erythromycin MIC >or= 1 mg/L); erm(B) was the most common macrolide resistance genotype (58.8%), followed by mef(A) (37.2%). The most common pneumococcal serotypes were 6B (19.7%), 19F (13.7%), 23F (13.5%) and 6A (12.8%). Telithromycin and amoxicillin-clavulanate were the most active antibacterials against S. pneumoniae (99.8% and 99.6% susceptibility, respectively). CONCLUSION: Approximately one-third of H. influenzae isolates from paediatric patients in Japan are BLNAI/BLNAR, mainly as a result of clonally diverse PBP3 mutations. Together with the continued high prevalence of pneumococcal macrolide resistance, these results may have implications for the clinical management of paediatric RTIs in Japan. SN - 1476-0711 UR - https://www.unboundmedicine.com/medline/citation/17697316/Mechanisms_molecular_and_sero_epidemiology_of_antimicrobial_resistance_in_bacterial_respiratory_pathogens_isolated_from_Japanese_children_ L2 - https://ann-clinmicrob.biomedcentral.com/articles/10.1186/1476-0711-6-7 DB - PRIME DP - Unbound Medicine ER -