ObjectivesThe objectives of this study were to determine CTX-M-producing Escherichia coli ST131 strain prevalence in stool specimens from healthy subjects in central China and to molecularly characterize clonal groups.MethodsFrom November 2013 to January 2014, stool specimens from healthy individuals in Hunan Province were screened for ESBL-producing E. coli using chromogenic medium and CTX-M genotypes and phylogenetic groups were determined. ST131 clonal groups were detected by PCR and characterized for antibiotic resistance, fimH, gyrA and parC alleles, plasmid-mediated quinolone resistance determinants, virulence genotypes and PFGE patterns.ResultsAmong 563 subjects, 287 (51.0%) exhibited the presence of faecal ESBL-producing E. coli, all of which produced CTX-M enzymes. The most common CTX-M genotypes were CTX-M-14 (48.4%), CTX-M-15 (27.5%) and CTX-M-27 (15.0%). Of the 287 CTX-M-producing isolates, 32 (11.1%) belonged to the ST131 clone. O16-ST131 isolates were dominant (75%) and contained the fimH41 allele. The remaining eight (25%) ST131 isolates were of the O25b subgroup and contained fimH30 or fimH41. Ciprofloxacin resistance was found in 100% of the O25b-ST131 isolates, whereas only 8% of the O16-ST131 isolates were resistant. All of the O25b-ST131 isolates except one showed gyrA1AB and parC1aAB mutations; most of the O16-ST131 isolates had gyrA1A and parC1b mutations. The virulence genotypes of O16-ST131 resembled those of the O25b-ST131 isolates. The 32 ST131 isolates formed one large group at the 64% similarity level. They comprised 15 PFGE groups (defined at ≥85% similarity).ConclusionsO16-ST131 isolates have emerged as the predominant type of ST131 isolate in faecal CTX-M-producing E. coli in healthy individuals in China.

BackgroundThe emerging pks‐positive (pks+) strains have aroused great public concern recently. Colibactin, encoded by pks gene cluster, has been reported to be involved in DNA damage and increased virulence. Little is known about its prevalence among Klebsiella pneumoniae‐induced bloodstream infections (BSIs). Therefore, the aim of this study was to investigate the prevalence of pks gene cluster, and molecular and clinical characteristics of K pneumoniae‐induced BSIs.MethodsA total of 190 non‐duplicate K pneumoniae bloodstream isolates were collected at a university hospital in China from March 2016 to March 2018. Molecular characteristics including capsular types, virulence, and pks genes were detected by polymerase chain reaction (PCR). Clinical characteristics and antimicrobial susceptibility were also investigated.ResultsOverall, 21.6% (41/190) of K pneumoniae bloodstream isolates were hypervirulent K pneumoniae(hvKP). The prevalence of pks gene cluster was 26.8% (51/190). The positive rates of K1, K57, and genes associated with hypervirulence, that is, rmpA, wcaG, mrkD, allS, ybtS, kfu,and iucA, were significantly higher in the pks+isolates than the pks‐negative (pks −) isolates (P < 0.05), while the pks+ isolates were significantly less resistant to 11 antimicrobial agents than the pks − isolates. Multivariate analysis showed diabetes mellitus, and K1 and K20 capsular types as independent risk factors for pks + K pneumoniaebloodstream infections.ConclusionsThe pks + K pneumoniae was prevalent in individuals with bloodstream infections in mainland China. The high rates of hypervirulent determinants among pks + K pneumoniaerevealed the potential pathogenicity of this emerging gene cluster. Diabetes mellitus, and K1 and K20 capsular types were identified as independent risk factors associated with pks+ K pneumoniaebloodstream infections. This study highlights the significance of clinical awareness and epidemic surveillance of pks+strains.

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Interleukin 35 (IL-35) is a newly discovered anti-inflammatory cytokine. Recent studies have indicated that it plays a crucial role in the pathogenesis of autoimmune diseases. In humans, IL-35 is predominantly secreted from regulatory T cells. This study aimed to measure serum IL-35 levels in patients with rheumatoid arthritis (RA) and in control individuals, and analyze its association with disease indicators of RA. One hundred patients with RA were recruited, and 50 volunteers were enrolled as healthy controls. Serum IL-35 levels were measured using an enzyme-linked immunosorbent assay kit. RA patients showed significantly lower serum levels of IL-35 compared with healthy controls (p < 0.001). RA patients suffering from erosive arthritis (n = 31) had lower IL-35 levels than those with non-erosive arthritis (n = 69, p = 0.022). In addition, serum IL-35 level was significantly lower in 22 patients with elevated percentage (> 75%) of neutrophils (p < 0.001). Correlation analysis indicated a significantly negative association between IL-35 and age, rheumatoid factor (RF), or percentage of neutrophils. In contrast, the serum IL-35 levels were not significantly different between patients with anti-cyclic citrullinated peptide (CCP) antibodies (n = 78) and those without anti-CCP antibodies (n = 22). However, among patients without anti-CCP antibodies, the serum IL-35 levels were lower in patients with erosive arthritis (n = 8) than those patients without erosion (n = 14) (p < 0.001), although no significant difference was detected in patients with anti-CCP antibodies. In conclusion, IL-35 plays a protective role in the pathogenesis of RA.