Genetic and Phenotypic Variation of Campylobacter jejuni NCTC11168 Caused by flhA Mutation during Laboratory Passage / 生物医学与环境科学（英文）

OBJECTIVE@#Campylobacter jejuni NCTC11168 is commonly used as a standard strain for flagellar biosynthesis research. In this report, two distinguished phenotypic isolates (CJ1Z, flhA mutant strain, lawn; CJ2S, flhA complemented strain, normal colony) appeared during laboratory passages for NCTC11168.@*METHODS@#Phenotypic assessments, including motility plates, transmission electron microscopy, biofilm formation assay, autoagglutination assay, and genome re-sequencing for these two isolates (CJ1Z, flhA mutant strain; CJ2S, flhA complemented strain) were carried out in this study.@*RESULTS@#Transmission electron microscopy revealed that the flagellum was lost in CJ1Z. Phenotypic assessments and genome sequencing of the two isolates were performed in this study. The capacity for biofilm formation, colony auto-agglutination, and isolate motility was reduced in the mutant CJ1Z. Comparative genomic analysis indicated a unique native nucleotide insertion in flhA (nt, 2154) that caused the I719Y and I720Y mutations and early truncation in flhA.@*CONCLUSION@#FlhA has been found to influence the expression of flagella in C. jejuni. To the best of our knowledge, this is the first study to describe the function of the C-terminal of this protein.

Antibiotics susceptibility and genetic characteristics analysis for quinolone resistant Campylobacter jejuni isolated from China / 中国人兽共患病学报

According to CLSI,agar dilution method was used to analyze the minimum inhibitory concentrations (MIC) of the nalidixic acid and ciprofloxacin for the isolates from different sources.Mutations in the quinolone resistant determining region (QRDR) of gyrA and gyrB were examined by DNA sequencing of 102 resistant C.jejuni isolates and 27 sensitive isolates.The results showed that 218 isolates(93.16％) were resistant to nalidixic acid among the entire tested 234 isolates.Among these,the resistant rates of the isolates from chicken feaces,duck feaces,human feaces,food animal and cow feaces were 100.00％,100.00％,97.96％,97.83％ and 77.97％,respectively.The 211 isolates(90.17％) were resistant to ciprofloxa-cin.Among these,the resistant rates of the isolates from chicken feaces,duck feaces,human feaces,food animal and cow feaces were 100.00％,100.00％,91.84％,95.65％ and 77.97％,respectively.The differences were both statistically significant.All of the resistant isolates on the QRDR of gyrA had Thr-86-Ile mutation.However,the point substitutions in gyrB gene were synonymous mutations.The results indicated that the C.jejuni isolates in this study showed highly resistant to nalidixic acid and ciprofloxacin.The Thr-86-Ile mutation on the QRDR of gyrA can cause highly resistant to quinolone and fluoroquinolone for C.jejuni.

Genetic and Antibiotic Resistance Characteristics of Campylobacter jejuni Isolated from Diarrheal Patients, Poultry and Cattle in Shenzhen / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate genetic and antibiotic resistance characteristics of Campylobacter jejuni (C. jejuni) isolated from Shenzhen.</p><p><b>METHODS</b>Multilocs sequence typing and agar dilution methods were used to define the genotype and antibiotic resistance of C. jejuni, respectively.</p><p><b>RESULTS</b>In total, 126 C. jejuni strains were isolated. The prevalence of C. jejuni was 5.3% in diarrheal patients. The prevalence in poultry meat (36.5%) was higher than that in cattle meat (1.1%). However, the prevalence in poultry cloacal swabs (27.0%) was lower than that in cattle stool (57.3%). Sixty-two sequence types were obtained, among which 27 of the STs and 10 alleles were previously unreported. The most frequently observed clonal complexes were ST 21 (11.9%), ST-22 (10.3%), and ST-403 (7.1%). ST-21, ST-45, ST-354, ST-403, and ST-443 complexes overlapped between isolates from patients and cattle, whereas ST-45 and ST-574 complexes overlapped between isolates from patients and poultry. All C. jejuni were resistant to at least one antibiotic. The highest resistance rate was toward ciprofloxacin (89.7%), followed by tetracycline (74.6%), and nalidixic acid (69.0%).</p><p><b>CONCLUSION</b>This is the first report of the genotypes and antibiotic resistance of C. jejuni in Shenzhen. Overlapping clonal complexes were found between isolates from patients and cattle, and between patients and poultry.</p>

In vitro protein expression profile of Campylobacter jejuni strain NCTC11168 by two-dimensional gel electrophoresis and mass spectrometry / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the protein expression profiles of the major food-borne pathogen Campylobacter jejuni NCTC11168.</p><p><b>METHODS</b>Membrane and soluble cellular proteins were extracted from the genome-sequenced C. jejuni strain NCTC11168. Protein expression profiles were determined using two-dimensional gel electrophoresis (2-DE). All the detected spots on the 2-DE map were subjected to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF) analysis.</p><p><b>RESULTS</b>A total of 537 and 333 spots were detected from the whole cell and membrane-associated proteins of C. jejuni NCTC11168 cultured on Columbia agar medium at 42 °C by 2-DE and Coomassie Brilliant Blue staining, respectively. Analyses of whole cell and membrane-associated proteins included 399 and 133 spots, respectively, which included 182 and 53 functional proteins identified by MALDI-TOF/TOF analysis.</p><p><b>CONCLUSION</b>The comprehensive expression protein profiles of C. jeuni NCTC11168 obtained in this study will be useful for elucidating the roles of these proteins in further pathogenesis investigation.</p>

Proteome analysis of Neisseria meningitidis serogroup strains C associated with outbreaks in China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>During 2003-2005, an outbreak of meningitis due to Neisseria meningitidis serogroup C occurred in China. With the aim to find strain clues result in the final epidemics, the ancestral strain 053442, a clinical isolate, and a carrier strain 053426 with different gene type were analyzed.</p><p><b>METHODS</b>Clinical strain 053442 and carrier strain 053426 were cultured on GC agar plates under the same condition. Two-dimensional electrophoresis was performed using the pH 3-10 nonlinear IPG strips of 24 cm length, and all the protein spots were identified by matrix-assisted laser desorption/ionization time of flight spectrometry.</p><p><b>RESULTS</b>502 and 380 protein spots were identified in 053426 and 053442 respectively, relating to 266 and 202 different genes covering a wide range of cellular functions. The express volume and number of proteins involved in energy metabolism, protein synthesis and amino acid biosynthesis in 053426 were higher than in 053442. Virulence factor Opa, Opc and a series of proteins involved in pilus assembly and retraction were identified in 053442, which appear to be of primary importance in colonization and invasion of human cells. Compared to 053442, virulence protein species were less in 053426, with lower express volumes too. No Opa and Opc were detected in 053426.</p><p><b>CONCLUSIONS</b>The different protein expression profiles of the clinical strain 053442 and carrier strain 053426 in the present study provide some clues of the different pathogenicity of the two strains, which may account for result in the final epidemics.</p>

Multilocus sequence typing of methicillin-resistant Staphylococcus aureus / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze multilocus sequence typing (MLST) of methicillin-resistant Staphylococcus aureus (MRSA) strains in 2000 and 2005, and get a primary knowledge of MLST Characterization of MRSA.</p><p><b>METHODS</b>Sequence analysis was conducted on seven allelic genes of 29 methicillin-resistant Staphylococcus aureus strains and 2 methicillin-sensitive Staphylococcus aureus (MSSA) strains and the allelic profiles were gained from internet database.</p><p><b>RESULTS</b>All 12 MRSA strains in 2000 were sequence type (ST) 239 and 10 MRSA strains in 2005 were ST239, while 7 MRSA strains in 2005 were new types, ST5 (41.18%, 7/17). ST6 and ST630 were allelic profiles of 2 MSSA strains. ST239 was the most prevalent allelic profile (75.86%, 22/29), while ST5 was the second prevalent allelic profile (24.14%, 7/29) among all isolates.</p><p><b>CONCLUSION</b>ST239 and ST5 are the most prevalent MRSA clones in this research. MRSA strains have different allelic profile from MSSA strains. MLST might provide an unambiguous method for assigning MRSA and MSSA isolates to known clones or assigning them as novel clones via the internet. Further studies need to be taken by increasing strains.</p>

Multi-PCR identification and virulence genes detection of Campylobacter jejuni isolated from China / 中华流行病学杂志

<p><b>OBJECTIVE</b>This study was to simultaneously identify Campylobacter jejuni and Campylobacter coli isolates in China by Multi-PCR assay and to study the prevalence of six virulence and toxin genes on them.</p><p><b>METHODS</b>A multi-PCR method with three sets of primers specifically designed for application of a 16S rRNA as a universal control, mapA, ceuE based on the specific sequence of C. jejuni and C. coli, was applied to detect 65 Campylobacter isolates from China. Another two separately PCR Primers were directed towards the hippuricase gene (hipO) characteristic of C.jejuni and glyA gene characteristic of C. coli were performed for further confirmation. The presence of the cadF, virB11, flaA, cdtA, cdtB, cdtC genes among these 65 strains were investigated by PCR.</p><p><b>RESULTS</b>From multi-PCR detection, 42 isolates belonged to C. jejuni, other 23 isolates belong to C. coli. Data showing the identification were 100% in concordance with the separated PCR for hipO and glyA amplification. The efficiency (100%) of identification by these three primers multi-PCR method was higher than the biochemical test (83.1%). The cadF and flaA genes were detected from 100% (65/65) of the isolates and the PCR product of each gene were identical with each isolate. Only 10.8% (7/65) of the isolates were positive for virB11. The cdtA gene was found in 92% (60/65) of the isolates. 97.6% (41/42) of C. jejuni had cdtB gene, whereas no PCR product with this primers for all the C. coli isolates. cdtC was presented in all the isolates but the lengths of PCR products were different. For C. jejuni, it was 555 bp, for C. coli, it was about 465 bp.</p><p><b>CONCLUSION</b>This three primers simultaneous multi-PCR method seemed to be useful for the identification of C. jejuni and C. coli isolates from China since cadF and flaA genes were widely spread in Campylobacter isolates in this country. The present report on virB11 was similar to previous reports from other countries, but the distribution of cdt gene cluster in Campylobacter species isolated from China might be different.</p>