As recently indiscriminate abuse of existing antibiotics in both clinical and veterinary treatment leads to proliferation of antibiotic resistance in microbes and poses a dilemma for the future treatment of such bacterial infection, antimicrobial resistance has been considered to be one of the currently leading concerns in global public health, and reported to widely spread and extended to a large variety of microorganisms. In China, as one of the currently worst areas for antibiotics abuse, the annual prescription of antibiotics, including both clinical and veterinary treatment, has approaching 140 gram per person and been roughly estimated to be 10 times higher than that in the United Kingdom, which is considered to be a potential area for the emergence of “Super Bugs”. Based on the integrons surveillance in Guangzhou, China in the past decade, this review thus aimed at summarizing the role of integrons in the perspective of both clinical setting and environment, with the focus on the occurrence and prevalence of class 1, 2 and 3 integrons.

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Staphylococcus aureus (S. Aureus) is a common food-borne pathogenic microorganism. Biofilm formation remains the major obstruction for bacterial elimination. The study aims at providing a basis for determining S. aureus biofilm formation. 257 clinical samples of S. aureus isolates were identified by routine analysis and multiplex PCR detection and found to contain 227 MRSA, 16 MSSA, 11 MRCNS, and 3 MSCNS strains. Two assays for quantification of S. aureus biofilm formation, the crystal violet (CV) assay and the XTT (tetrazolium salt reduction) assay, were optimized, evaluated, and further compared. In CV assay, most isolates formed weak biofilm 74.3 %), while the rest formed moderate biofilm (23.3 %) or strong biofilm (2.3 %). However, most isolates in XTT assay showed weak metabolic activity (77.0 %), while the rest showed moderate metabolic activity (17.9 %) or high metabolic activity (5.1 %). In this study, we found a distinct strain-to-strain dissimilarity in terms of both biomass formation and metabolic activity, and it was concluded from this study that two assays were mutual complementation rather than being comparison.

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Staphylococcus is a common gram‐positive pathogen, which has been considered to be a leading concern to public health and food safety due to the multi‐drag resistance and virulence. As is known, most Staphylococcus tend to form biofilm both during various food processing procedures and in environment, and the bacteria in biofilms show a number of specific advantages over planktonic bacteria due to strong resistance ability. As a consequence, inhibition and removal of Staphylococcus biofilm is difficult for food safety during processing. The present review aims to discuss and demonstrate the formation and development of Staphylococcus biofilm based on food safety account under the background of both phenotype and genetic regulation, providing scientific reference for control strategy. Practical application As a common foodborne pathogen, Staphylococcus aureus in food industry is a potential harm to the health of both customer and stuff. Biofilm plays a significant role in bacterial survival, tolerant to environmental stresses. Thus, a comprehensive understanding of biofilm is of essential and urgent need. This review of biofilm of Staphylococcus aureus illustrated the biofilm in food industry and its formation, influential factor, quantification, genetic regulation mechanism, and control strategies, which provided a background of Staphylococcus aureus biofilm prevention in food industry.

Staphylococcus aureus is one of the representative foodborne pathogens which forms biofilm. Antibiotics are widely applied in livestock husbandry to maintain animal health and productivity, thus contribute to the dissemination of antimicrobial resistant livestock and human pathogens, and pose a significant public health threat. Effect of antibiotic pressure on S. aureus biofilm formation, as well as the mechanism, remains unclear. In this study, the regulatory mechanism of low concentration of ampicillin on S. aureus biofilm formation was elucidated. The viability and biomass of biofilm with and without 1/4 MIC ampicillin treatment for 8 h were determined by XTT and crystal violet straining assays, respectively. Transcriptomics analysis on ampicillin-induced and non-ampicillin-induced biofilms were performed by RNA-sequencing, differentially expressed genes identification and annotation, GO functional and KEGG pathway enrichment. The viability and biomass of ampicillin-induced biofilm showed dramatical increase compared to the non-ampicillin-induced biofilm. A total of 530 differentially expressed genes (DEGs) with 167 and 363 genes showing up- and down-regulation, respectively, were obtained. Upon GO functional enrichment, 183, 252, and 21 specific GO terms in biological process, molecular function and cellular component were identified, respectively. Eight KEGG pathways including “Microbial metabolism in diverse environments”, “S. aureus infection”, and “Monobactam biosynthesis” were significantly enriched. In addition, “beta-lactam resistance” pathway was also highly enriched. In ampicillin-induced biofilm, the significant up-regulation of genes encoding multidrug resistance efflux pump AbcA, penicillin binding proteins PBP1, PBP1a/2, and PBP3, and antimicrobial resistance proteins VraF, VraG, Dlt, and Aur indicated the positive response of S. aureus to ampicillin. The up-regulation of genes encoding surface proteins ClfB, IsdA, and SasG and genes (cap5B and cap5C) which promote the adhesion of S. aureus in ampicillin induced biofilm might explain the enhanced biofilm viability and biomass.

A number of genetic loci have been proposed to be associated with persistent hepatitis B virus (HBV) infection. This study aimed to evaluate the association and interaction of susceptible genes with HBV persistence in a Chinese population. A total of 17 polymorphisms in 9 candidate genes were studied in 361 Chinese chronic hepatitis B patients and 304 patients who recovered spontaneously. Distributions of susceptible polymorphisms were examined in healthy Chinese and Caucasian populations. Gene-gene interactions were tested by the multifactor dimensionality reduction (MDR) method. The TNF -308 G/G genotype and G allele, IL-10RB codon 47 A allele, and MCP-1 -2518 G/G genotype and G allele were more frequent in patients than controls (P < 0.01, after multiple corrections Pc < 0.05), while the frequencies of TNF -308 A/G genotype and IL-10 -592 A/A genotype were significantly higher in controls than in the patient group (Pc < 0.05). The frequencies of the risk allele MCP-1 -2518 G and CTLA4 6230 G were much higher in Chinese than in the Caucasian groups (P < 0.001). An interaction between CCR5 -2459, TNFA -863, IL-10RB codon 47, and MCP-1 -2518 was detected by MDR (P = 0.001). The results indicate that genetic determinants may affect the outcome of HBV infection in both independent and synergic manners. J. Med. Virol. 82:371-378, 2010. (c) 2010 Wiley-Liss, Inc.