Molecular Epidemiological Analysis of Group A Streptococci Isolated from Children in Chaoyang District of Beijing, 2011:emm Types, Virulence Factor Genes and Erythromycin Resistant Genes

Group A streptococcus （GAS） causes a wide range of diseases in the human population. GAS diseases are more common in children than in adults, with clinical manifestations ranging from pharyngitis and impetigo to invasive infections and post streptococcal sequelae, such as acute rheumatic fever and acute post-streptococcal glomerulonephritis[1]. GAS harbors a host of virulence factors that contribute to its complex pathogenicity and differences in the disease severity and frequency. M protein, one of the major virulence factors, is encoded by the emm gene induces a type of specific host immune response and confers antiphagocytic properties.

Phylogenetic Analysis of Virulence Factor Genes in Salmonella from Chicken

Salmonella is a common genus of seriously harmful food-borne zoonotic bacteria. Humans and animals may be infected with Salmonella through ingestion of SalmoneUa-contaminated eggs and poultry meat. Therefore, in order to reduce the incidence of Salmonella infections, it is crucial to explore the pathogenic mech- anism of Salmonella. invA and invE are major virulence factor genes that encode invasion proteins of Salmonella. In order to explore the pathogenic mechanism of Salmonella, phylogenetic analysis of major virulence factor genes in 33 Salmonella strains isolated from chicken was analyzed. According to the results, ivnA gene was successfully amplified from 33 Salmonella strains; ivnE gene was successfully amplified from 32 Salmonella strains, ivnA nucleotide sequences shared 72.9% - 97.6% homology among 12 sequenced Salmonella strains and shared 78.9% - 97.2% homology with those in GenBank ; ivnE nucleotide sequences shared over 95.3% homology among 23 sequenced Salmonella strains and shared 89.6% -98.6% homology with those in GenBank, which exhibited no genetic relationship to other organisms. This study provided the basis for rapid molecular detection, epidemiological research and molecular pathogenesis analysis of Salmonella.

A global perspective on microbial risk factors in effluents of wastewater treatment plants

Effective monitoring and management of microbial risk factors in wastewater treatment plants(WWTPs)effluents require a comprehensive investigation of these risks.A global survey on microbial risk factors in WWTP effluents could reveal important insights into their risk features.This study aims to explore the abundance and types of antibiotic resistance genes(ARGs),virulence factor genes(VFGs),the vector of ARG/VFG,and dominant pathogens in global WWTP effluents.We collected 113 metagenomes of WWTP effluents from the Sequence Read Archive of the National Center for Biotechnology Information and characterized the microbial risk factors.Our results showed that multidrug resistance was the dominant ARG type,while offensive virulence factors were the most abundant type of VFGs.The most dominant types of ARGs in the vector of plasmid and phage were both aminoglycoside resistance,which is concerning as aminoglycosides are often a last resort for treating multi-resistant infections.Acinetobacter baumannii was the most dominant pathogen,rather than Escherichia coli,and a weak negative correlation between Escherichia coli and two other dominant pathogens(Acinetobacter baumannii and Bacteroides uniformis)suggests that using Escherichia coli as a biological indicator for all pathogens in WWTP effluents may not be appropriate.The Getah virus was the most dominant virus found in global WWTP effluents.Our study presents a comprehensive global-scale investigation of microbial risk factors in WWTP effluents,providing valuable insights into the potential risks associated with WWTP effluents and contributing to the monitoring and control of these risks.

The Isolation of Vibrio cholera and Other Enteric Bacteria with Molecular Characterization of Vibrio cholera during the Outbreak of Baghdad/Iraq in 2015

Vibrio cholera, causing acute watery diarrhea known as cholera disease, affects all ages and both genders. Cholera infection outbreaks in Iraq have been reported for several years. The recent cholera outbreak, emerged throughout 2015, was investigated using bacteriological laboratory tests, singleplex and multiplex PCR technique for the detection of V. cholera from stool samples. Furthermore the toxigenic potential coupled with the antibiotic susceptibility test for cholera and other bacteria were also investigated. The stool samples were collected from 5698 patients admitted to Al-Yarmouk Teaching hospital and health care centers in Baghdad/Al-Karkh, Iraq, from the 1st of August to the 30th of December 2015. The V. cholera was isolated from 194 cases (3.4% of the cases age between 21 - 50 years). In addition, other enteric infections: Salmonellosis and Shigellosis 7 and 21 respectively, protozoan parasite Giardia lamblia and Entamoeba histolytica 2 and 43 cases respectively were also reported. High percentage of V. cholera infection was detected in October (122 cases, 62.8%), compared with other enteric infections that show high percentage of diarrheal disease in September and November. The results have confirmed that the cholera outbreak was caused by V. cholera O1, biotype El Tor, and serotype Inaba. Seven virulence genes were identified ctxA, toxR, zot, ace, rfbO1, tcpA and ompW. Moreover, the cholera isolated strains were found sensitive to most antibiotic but resistant to nalidixic acid.