Characterization and genomic analysis of JC01, a novel bacteriophage infecting Cronobacter sakazakii.

The lytic bacteriophage JC01 was isolated using a strain of Cronobacter sakazakii previously isolated from powdered infant formula (PIF). The complete genome sequence of phage JC01 was determined. The double-stranded DNA genome of phage JC01 is composed of 61,736 bp with a G + C content of 58.9%, and it contains 76 putative open reading frames (ORFs) without any tRNA genes. The predicted ORFs were classified into functional groups, including DNA manipulation, transcription, phage packaging, phage structure, host lysis, and hypothetical proteins. Based on overall nucleotide sequence comparisons, calculation of phage intergenomic similarities, and phylogenetic analysis, JC01 appears to be a novel bacteriophage infecting C. sakazakii.

Characterization and Genomic Analysis of Escherichia coli O157:H7 Bacteriophage FEC14, a New Member of Genus Kuttervirus.

Escherichia coli O157:H7 is an important foodborne pathogen that has become a major worldwide factor affecting the public safety of food. Bacteriophage has gradually attracted attention because of its ability to kill specific pathogens. In this study, a lytic phage of E. coli O157:H7, named FEC14, was isolated from hospital sewage. Transmission electron microscopy analysis showed that phage FEC14 had an isometric head 80 ± 5 nm in diameter and a contractile tail whose terminal spikes present an umbrella-like structure. Phage FEC14 revealed 158,639 bp double-stranded DNA, with the G+C content of 44.6%, 209 ORFs and four tRNAs. Genome DNA of FEC14 could not be digested by some endonucleases. Many of the features of phage FEC14 are very similar to those of the newly classified genus "Kuttervirus", including morphology, genome size and organization, etc. Phage FEC14 is proposed to be a new isolate of genus "Kuttervirus" within the family Ackermannviridae, moreover, the endonuclease resistance of phage FEC14, has priority over other genera of bacteriophages for its use in biocontrol of foodborne pathogens.

Association study between an outbreak of Guillain-Barre syndrome in Jilin, China, and preceding Campylobacter jejuni infection.

From June to July 2007, 36 cases of Guillain-Barre syndrome (GBS) occurred in a township in north China. Serological study and bacteria culture were performed to investigate the association between preceding Campylobacter jejuni infection and this GBS outbreak. Anti-C. jejuni antibodies were found in significantly higher numbers of GBS patients (IgM 84%, IgG 87.5%) than in healthy inspection cases (IgM 33%, IgG 27%). IgG anti-GM1 was the dominant anti-ganglioside antibody among the GBS patients. Seven C. jejuni isolates (four from human stool and three from poultry specimens taken from the patients' houses) were obtained. Serotyping and molecular analysis were used to investigate the genetic relatedness among these C. jejuni isolates. The four human isolates, collected from residents of the same district, were indistinguishable by both pulsed-field gel electrophoresis and multilocus sequence typing, suggesting these patients had a common source of infection. A new sequence type, sequence type-2993, was assigned to the human C. jejuni isolates, three of which belonged to Penner serotype heat-stable (HS):41. Both serotype and molecular subtype of the human C. jejuni isolates were different from those of isolates obtained from poultry specimens. Our results suggest that the antecedent C. jejuni infection triggered this GBS outbreak in China.