Lactobacilli have been shown to inhibit the proliferation of several types of cancer cells, but the effects of vaginal Lactobacilli on cervical cancer cells have seldom been reported. We incubated Caski cells with supernatants of predominant strains in the vagina and investigated their effects on cell growth and the possible mechanisms. Cell-free supernatants of Lactobacillus crispatus, L. jensenii, and L. gasseri were prepared and purified. Caski cells were treated with various concentrations of Lactobacillus supernatants (LS). The effect of LS on cell growth was investigated using MTT assays. The influence of LS on the cell cycle and expression of human papillomavirus (HPV) E6 and E7 oncogenes was determined by flow cytometry and RT-PCR, respectively. LS-inhibited Caski cell proliferation caused morphological changes in a pH-independent manner. Flow cytometric analysis revealed that cells exposed to LS exhibited a significant increase of cell number in S phase and a strong decrease of cell number in G2/M phase. Expression of HPV E6 and E7 oncogenes, as well as CDK2 and cyclin A was decreased after treatment with LS, while expression of p21 was increased. Supernatants of L. crispatus, L. jensenii, and L. gasseri have inhibitory effects on the viability of cervical cancer cells via regulation of HPV oncogenes and cell cycle-related genes. Lactobacillus, as a promising treatment for cancer, is being assessed for its effect, and these results provide further evidence in this respect.

Antibiotic exposure, Clostridium difficile toxins, and spore formation are key factors involved in the pathogenesis of Clostridium difficile infection (CDI). A high incidence of CDI due to toxin A- B+ strains, which were classified into two genotypes (ST81 and ST37) by multilocus sequence typing, was identified in Beijing Friendship Hospital in 2016-2017. ST81 was the most prevalent type, accounting for 81.25% of toxin A- B+ strains. ST81 corresponded to a novel PCR ribotype, PKI-017, with one less band than ST37/ribotype 017 in PCR ribotyping. All ST81 strains showed a high level of ciprofloxacin resistance (MICs ≥ 64 μg mL-1) and moxifloxacin resistance (MICs ≥ 128 μg mL-1) with the amino acid substitutions Thr82 to Ile in GyrA and Ser416 to Ala in GyrB. There was either no mutation or only the single amino acid mutation Thr82 to Ile in the GyrA subunit of ST37/ribotype 017 strains, which had lower MICs of ciprofloxacin (4-64 μg mL-1) and moxifloxacin (4-16 μg mL-1). In addition, ST81 strains exhibited higher spore formation ability than ST37/ribotype 017 strains. Overall, our results indicated that ST81 strains had unique characteristics distinguishable from ST37 strains and emphasized the importance of ongoing surveillance for this new genotype.

Because the epidemiology of Clostridium difficile infection (CDI) is region-specific, the present study was undertaken to examine the epidemiology of C difficile outbreaks in Beijing, China.Eighty nonduplicate isolates were collected from March, 2016 to December, 2016. The molecular type and phylogenetic analysis were evaluated by multilocus sequence typing (MLST). The minimum inhibitory concentrations (MICs) for 11 antibiotics and the resistance mechanisms were investigated.Sixty-five toxigenic strains (81.25%), including 22 tcdA-B+CDT- strains (27.5%) and 43 tcdA+B+CDT- strains (53.75%), and also 15 nontoxigenic strains (tcdA-B-CDT-; 18.75%) were detected. MLST identified 21 different sequence types (STs), including 2 novel types (ST409 and ST416). All isolates were susceptible to metronidazole, vancomycin, fidaxomicin, piperacillin/tazobactam, and meropenem, and all were effectively inhibited by emodin (MICs 4–8 μg/mL). The resistance rates to rifaximin, ceftriaxone, clindamycin, erythromycin, and ciprofloxacin were 8.75%, 51.25%, 96.25%, 81.25%, and 96.25%, respectively; 81.25% (65/80) of isolates were multidrug-resistant. Amino acid mutations in GyrA and/or GyrB conferred quinolone resistance. One novel amino acid substitution, F86Y in GyrA, was found in 1 CIP-intermediate strain. The erm(B) gene played a key role in mediating macrolide-lincosamide-streptogramin B (MLSB) resistance. Erm(G) was also found in erm(B)-negative strains that were resistant to both erythromycin and clindamycin. RpoB mutations were associated with rifampin resistance, and 2 new amino mutations were identified in 1 intermediate strain (E573A and E603N).Regional diversity and gene heterogeneity exist in both the ST type and resistant patterns of clinical C difficile isolates in Northern China.