Comparative characterization of the virulence gene clusters (lipooligosaccharide [LOS] and capsular polysaccharide [CPS]) for Campylobacter coli, Campylobacter jejuni subsp. jejuni and related Campylobacter species

Abstract Background The molecular characterization of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) isolates is not well studied. Our goal was to investigate the molecular epidemiology of CR-hvKP strains that were isolated from a Chinese hospital. Results All clinical carbapenem-resistant K. pneumoniae (CR-KP) isolates were collected and identified from patient samples between 2014 and 2017 from a Chinese hospital. The samples were subjected to screening for CR-hvKP by string test and the detection of the aerobactin gene. CR-hvKP isolates were further confirmed through neutrophil phagocytosis and a mice lethality assay. The CR-hvKP isolates were investigated for their capsular genotyping, virulence gene profiles, and the expression of carbapenemase genes by PCR and DNA sequencing. Multilocus sequence type (MLST) and pulsed-field gel electrophoresis (PFGE) were performed to exclude the homology of these isolates. Twenty strains were identified as CR-hvKP. These strains were resistant to imipenem and several other antibiotics, however, most were susceptible to amikacin. Notably, two isolates were not susceptible to tigecycline. Capsular polysaccharide synthesis genotyping revealed that 17 of the 20 CR-hvKP strains belonged to the K2 serotype, while the others belonged to serotypes other than K1, K2, K5, K20, and K57. The strains were found to be positive for 10 types of virulence genes and a variety of these genes coexisted in the same strain. Two carbapenemase genes were identified: blaKPC-2 (13/20) and blaNDM-1 (1/20). PFGE typing revealed eight clusters comprising isolates that belonged to MLST types ST25, ST11 and ST375, respectively. PFGE cluster A was identified as the main cluster, which included 11 isolates that belong to ST25 and mainly from ICU department. Conclusions Our findings suggest that hospital-acquired infections may contribute in part to the CR-hvKP strains identified in this study. It also suggests that ST25 CR-hvKP strain has a clonal distribution in our hospital. Therefore, effective surveillance and strict infection control strategies should be implemented to prevent outbreak by CR-hvKP strains in hospitals setting.

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Characterization of erythromycin resistance in Campylobacter jejuni and Campylobacter coli.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.35.10.1989 ◽

1991 ◽

Vol 35 (10) ◽

pp. 1989-1996 ◽

Cited By ~ 31

Author(s):

W Yan ◽

D E Taylor

Keyword(s):

Campylobacter Jejuni ◽

Campylobacter Coli ◽

Erythromycin Resistance

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Production and Characterization of a Monoclonal Antibody to Campylobacter jejuni

Journal of Food Protection ◽

10.4315/0362-028x-72.4.870 ◽

2009 ◽

Vol 72 (4) ◽

pp. 870-875 ◽

Cited By ~ 2

Author(s):

S. A. HEO ◽

R. NANNAPANENI ◽

M. G. JOHNSON ◽

J. S. PARK ◽

K. H. SEO

Keyword(s):

Monoclonal Antibody ◽

Campylobacter Jejuni ◽

Immunosorbent Assay ◽

Enzyme Linked Immunosorbent Assay ◽

Campylobacter Coli ◽

Carbonate Buffer ◽

Horse Blood ◽

Microaerobic Conditions ◽

Immunoglobulin Subclass

Campylobacter species are a group of spiral-shaped bacteria that can cause disease in humans and animals. We developed a high-affinity monoclonal antibody (MAb) probe that recognizes Campylobacter jejuni cells. Cell suspensions grown under microaerobic conditions at 42°C for 20 h on Bolton agar plates with lysed horse blood were used as live and heat-killed preparations, centrifuged at 8,000 × g for 20 min, and resuspended in carbonate buffer (pH 9.6) for coating on the enzyme-linked immunosorbent assay plates. BALB/c mice were immunized with C. jejuni sonicated cells at 107 CFU/ml to generate MAb-producing hybridoma clones. Of about 500 initial hybridoma clones, MAb 33D2, which reacted with C. jejuni and Campylobacter coli, was selected for further evaluation. MAb 33D2 is in the immunoglobulin subclass G2a and had relatively weaker reactivity with the C. coli strains tested. MAb 33D2 did not show any cross-reactions with the nine non-Campylobacter bacteria tested in the enzyme-linked immunosorbent assay and had a stronger affinity for C. jejuni as live versus heat-killed cells. In Western blot assays, MAb 33D2 recognized two major antigens of 62 and 43 kDa in extracts from C. jejuni cells but only one antigen of 62 kDa in extracts from C. coli cells.

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