Listeria monocytogenes (L. monocytogenes) is an important foodborne pathogen. In this study, 41 sporadic listeriosis cases were collected during 2016-2022, including 92.7% of invasive cases and 56.1% of pregnancy-associated cases. The age of cases ranged from 0 days to 88 years, with the majority occurring in individuals aged 20 to <30 years. Serotype 1/2 b was most prevalent among 43 L. monocytogenes isolates, followed by 1/2 a, 4 b, and 3a. Sixteen clonal complexes (CCs) were determined. CC87 occupied the top slot. Genome sequencing-based phylogeny results indicated that Chinese CC1, CC8, and CC87 isolates mostly clustered in clades separating from isolates from other countries. Meanwhile, a few Chinese isolates participated in cocirculating CC1, CC8, and CC87 in Asia, Europe, Africa, South America, North America, and Oceania. All isolates harbored LIPI-1 while LIPI-2 was absent. LIPI-3 and LIPI-4 exhibited an apparent relationship with lineage and CCs. It was notably that CC4, CC224, and CC619 carried both LIPI-3 and LIPI-4. inlB, inlC, inlH, inlK, ipeA, srtA, dltA, lap, ami, fbpA, stp, oatA, intA, prsA2, lgt, hpt, iplA1, bsh, mdrT, mdrM, and brtA existed in all isolates. The percentages of inlA, inlF, inlJ, aut, vip were 97.7%, 97.7%, 97.7%, 83.7%, and 83.7%. A premature stop codon mutation of position 1474(C→T) was detected, resulting in a truncated InlA with 491 aa. High susceptibility to penicillin (100%), ampicillin (100%), gentamicin (100%), erythromycin (100%), daptomycin (100%), meropenem (100%), trimethoprim-sulfamethoxazole (100%), vancomycin (97.7%), tetacycline (97.7%), chloramphenicol (97.7%), and ciprofloxacin (90.7%) was demonstrated. lin and fosX were present in 93.0% of the isolates, respectively. tetM and ermB were also detected. This comprehensive study enriched the understanding of listeriosis cases and diversity of clinical isolates, meanwhile, indicated the spread characteristics of CC1, CC8, and CC87 in China based on phylogeny analysis, providing fundamental data for developing targeting food safety interventions to prevent listeriosis.

Vibrio parahaemolyticus is a leading cause of seafood-associated gastroenteritis, posing increasing public health challenges globally. We conducted a large-scale molecular epidemiological analysis of 7932 clinical isolates collected from seafood-associated diarrheal patients in 69 sentinel hospitals across 11 prefecture-level cities in Zhejiang Province between 2016 and 2023. Whole-genome sequencing (WGS) was performed on 1261 representative isolates, supplemented by 11,555 publicly available genomes. We analyzed temporal serotype dynamics, antimicrobial resistance genes (ARGs), virulence factors, and pangenomic diversity, with an emphasis on the globally prevalent ST3 lineage. Notably, the O10:K4 serotype emerged as the second most common within ST3, increasing in prevalence from 40.0 % to 65.6 % over the study period. O10:K4 isolates exhibited a significantly higher frequency of tdh (96.3 % vs. 78.2 %) and complete T3SS2 effector gene clusters. Nearly all isolates harbored tet(35) and blaCARB-22, indicating widespread resistance. Comparative pangenome analysis revealed O10:K4-specific acquisitions in chemotaxis and LPS synthesis (e.g., per, mcpQ, fcl) and loss of key polyamine metabolism genes (aguA, puu operon). These findings suggest that the emergence and clonal expansion of the O10:K4 serotype represent a significant epidemiological shift characterized by enhanced virulence and multidrug resistance. Sustained genomic surveillance is imperative to guide seafood safety management and clinical interventions.

Enhanced microbial remediation represents a promising technique for the removal of polycyclic aromatic hydrocarbons (PAHs). However, high-efficiency remediation agents remain limited, including microbial resources and remediation materials. In this study, a novel strain of Pseudomonas xizangensis S4 was isolated from plateau lake sediment, exhibiting a fluoranthene degradation rate of 41.90 % at 50 ppm within 7 d. The key degradation genes identified through genomic and transcriptomic analyses included ndmC, dmpK, dmpB, and dmpH. The metabolites detected via GC-MS analysis were biphenyls, parabens, and phthalate esters. Based on the above results, the degradation mechanisms of fluoranthene were deduced. Furthermore, an efficient remediation agent was developed, utilizing potassium humate-modified biochar to immobilize bacterial cells. The developed remediation agent enhanced the removal efficiency by 16.71 % compared to the single strain. Thus, the application of potassium humate-modified biochar for the immobilization of P. xizangensis S4 represents a promising method for the remediation of PAH-contaminated soil.

Cereulide, which can be produced by Bacillus cereus, is strongly associated with emetic-type food poisoning outbreaks. It is an extremely stable emetic toxin, which is unlikely to be inactivated by food processing. Considering the high toxicity of cereulide, its related hazards raise public concerns. A better understanding of the impact of B. cereus and cereulide is urgently needed to prevent contamination and toxin production, thereby protecting public health. Over the last decade, a wide range of research has been conducted regarding B. cereus and cereulide. Despite this, summarized information highlighting precautions at the public level involving the food industry, consumers and regulators is lacking. Therefore, the aim of the current review is to summarize the available data describing the characterizations and impacts of emetic B. cereus and cereulide; based on this information, precautions at the public level are proposed.

Bacillus cereus is a major food-borne bacterial pathogen in the world, which can cause diarrhea and emetic syndrome. This study aimed to reveal the quantitative prevalence of B. cereus in ready-to-eat (RTE) rice products in Eastern China and to gain essential information on the characteristics of B. cereus isolates. A total of 91 out of the 1071 samples were positive for B. cereus. The contamination level of B. cereus in 0.5 % of RTE rice product samples outnumbered 103 CFU/g. The number of B. cereus attained 105−106 CFU/g in one sample. The distribution patterns of virulence genes in B. cereus isolates were identified. 84.6% of the B. cereus isolates had at least one enterotoxin or emetic toxin gene. The predominant pattern was XXV. 9.9% of isolates belonged to it and possessed one enterotoxin gene entFM. The occurrence rate of hblACD and nheABC was 36.3% and 47.3%, respectively. Antimicrobial susceptibility tests revealed a high resistance rate toward penicillin, and 23.1% of the isolates were multi-drug resistant. B. cereus isolates were genotyped by using ERIC-PCR. 89 genotypes were determined. The Hunter Gaston Discriminatory Index (HGDI) attained 0.9995. Relationships analysis revealed that Group A B. cereus isolates tended to carry hblA, hblC, hblD, nheA, nheB, and show resistance to penicillin/trimethoprim/sulfamethoxazole. This study was useful for updating the knowledge of the contamination status of B. cereus in RTE rice products in China.

Listeria monocytogenes is an important foodborne pathogen causing public concern. A total of 3354 retail foods in bulk were sampled and screened for L. monocytogenes. Seventy-three (2.2%) samples including 21 ready-to-eat (RTE) foods and 52 raw foods were confirmed positive for L. monocytogenes. Sushi and salmon sashimi occupied the top two slots in RTE foods with relatively high presence rate of 12.9 and 6.9%, respectively. Meanwhile, L. monocytogenes was found to be distributed unequally in raw foods; the presence rates in raw meat (3.5%) and poultry (3.8%) were significantly higher than that in raw seafood (1.3%). Notably, L. monocytogenes was not detected in raw freshwater food. The L. monocytogenes isolates belonged to four serotypes, 1/2a, 1/2b, 1/2c, and 4b, with the most prevalent serotype being 1/2a (47.9%). Eighteen sequence types (STs) and eighteen virulence types (VTs) containing four newly assigned VTs (VT180, VT181, VT182, and VT183) were determined via multilocus sequence typing (MLST) and multi-virulence-locus sequence typing (MVLST). Among the 73 L. monocytogenes isolates, 23 (31.5%) belonged to epidemic clones (ECs) including ECI, ECIV, ECV, ECVI, ECVIII and ECXI among which ECV was predominant. Antibiotic susceptibility tests revealed a high resistance rate (11.0%) to tetracycline. Moreover, we identified the distribution patterns of virulence genes of four Listeria pathogenicity islands (LIPI) in L. monocytogenes isolates. prfA, hly, plcA, plcB, mpl, actA genes in LIPI-1 and inlA, inlB, inlC, inlJ genes in LIPI-2 were detected in approximately all L. monocytogenes isolates. The distribution of both LIPI-3 genes and LIPI-4 genes exhibited association with lineage and ST. LIPI-4 genes were present exclusively in ST87 isolates. Relatedness analysis revealed the absence of distinct association between STs, ECs, LIPI-3 and LIPI-4 distribution and specific food groups. This study provided fundamental data for Chinese food safety authorities to grasp the contamination status of L. monocytogenes in foods, assess the potential risk of this pathogen and further address the safety issue of retail foods in bulk in China.