Objective: To understand the etiological characteristics of bacterial diarrhea in different areas, including large cities, mid-sized/small cities and rural area, in China. Methods: A cross-sectional surveillance was conducted in 17 provinces of China from 2010 to 2014. The acute diarrhea outpatients were selected from clinics or hospitals in large cities, mid-sized/small cities, including rural-urban fringe zones, and rural areas. The demographical and clinical characteristics of the patients were collected by using questionnaire, and stool samples were taken from them for laboratory detection of 17 kinds of bacteria. The differences in pathogen positive rates (PPR) and pathogen spectrum across the cases from three-type areas were compared. The different infection risk in different cases were analyzed with unconditional logistic regression model. Results: In our study, we enrolled 9 253 cases from large cities, 5 138 cases from rural areas and 13 683 cases from midsized/small cites. The pathogen with largest differences in infection rate across the three-type areas was Shigella (S.) flexneri (rural area: 5.81%, mid-sized/small city: 2.78%, large city: 0.46%), followed by Aeromonas (A.) hydrophila (rural area: 2.14%, mid-sized/small city: 0.96%, large city: 0.48%). Compared with cases in large cities, the cases in mid-sized/small cities and rural areas had higher infection risks for S. flexneri (mid-sized/small city: OR=6.481, 95%CI: 4.666-9.002, rural area: OR=11.304, 95%CI: 8.018-15.938) and A. hydrophila (mid-sized/small city: OR=1.992, 95%CI:1.401-2.832, rural area: OR=4.083, 95%CI: 2.833-5.884). The constituent ratio of diarrheagenic Escherichia coli and Salmonella increased with the urbanization development, while the ratios of Shigella and A. hydrophila had an opposite trend. S. sonnei (60.00%) was the predominant serogroup of Shigella in urban infections, while S. flexneri (77.37%) was the predominant serogroup in rural infections. Conclusion: The differences in pathogen spectrum of bacterial diarrhea were obvious across large cities, mid-sized/small cities and rural areas in China, especially the differences in the infection rates of S. flexneri and A. hydrophila.
Adolescent ; Adult ; Bacterial Infections/microbiology* ; Child ; China/epidemiology* ; Cross-Sectional Studies ; Diarrhea/microbiology* ; Dysentery/epidemiology* ; Escherichia coli/pathogenicity* ; Feces/virology* ; Female ; Humans ; Male ; Middle Aged ; Prevalence ; Rural Population ; Salmonella/pathogenicity* ; Shigella/pathogenicity* ; Suburban Population ; Urban Population

BACKGROUNDThe accuracy of nasopharyngeal aspirate (NPA) specimens in detecting lower respiratory pathogens remains controversial. The objective of this study was to evaluate the diagnostic accuracy of aspirates (NPAs) specimen in lower respiratory tract infections (LRTIs) in children.

METHODSThe prospective study was designed to collect the data of paired NPAs and bronchoalveolar lavage fluids from children with acute LRTIs from January 2013 to December 2015. All specimens were subjected to pathogen detection: bacterial detection by culture, Mycoplasma pneumoniae (Mp) detection by polymerase chain reaction assay and virus (influenza A and B viruses, parainfluenza virus [PIV] Types 1 and 3, respiratory syncytial virus, and adenovirus) detection by immunofluorescence assay. The diagnostic accuracy analysis of NPAs was stratified by age ≤3 years (n = 194) and >3 years (n = 294).

RESULTSWe collected paired specimens from 488 children. The positive rate of pathogen was 61.6%. For Streptococcus pneumoniae, NPA culture had the specificity of 89.9% and negative predictive value of 100% in age ≤3 years, the specificity of 97.2% and negative predictive value of 98.9% in age >3 years. For Mp, the positive predictive values of NPA was 77.4% in children ≤3 years, and 89.1% in children >3 years. For PIV III, NPA specimen had the specificity of 99.8% and negative predictive value of 96.5% in children ≤3 years. For adenovirus, NPA had the specificity of 97.8% and negative predictive value of 98.4% in age ≤3 years, the specificity of 98.9% and negative predictive value of 99.3% in age >3 years.

CONCLUSIONSNPAs are less invasive diagnostic respiratory specimens, a negative NPA result is helpful in "rule out" lower airway infection; however, a positive result does not reliably "rule in" the presence of pathogens.

Acinetobacter baumannii ; isolation & purification ; pathogenicity ; Adolescent ; Child ; Child, Preschool ; Clinical Laboratory Techniques ; methods ; Enterobacter aerogenes ; isolation & purification ; pathogenicity ; Escherichia coli ; isolation & purification ; pathogenicity ; Female ; Haemophilus influenzae ; isolation & purification ; pathogenicity ; Humans ; Infant ; Male ; Nasopharynx ; microbiology ; Prospective Studies ; Pseudomonas aeruginosa ; isolation & purification ; pathogenicity ; Respiratory Tract Infections ; diagnosis ; microbiology ; Sensitivity and Specificity ; Staphylococcus aureus ; isolation & purification ; pathogenicity ; Streptococcus pneumoniae ; isolation & purification ; pathogenicity

OBJECTIVETo investigate the change in the expression of tight junction protein ZO-1 in intestinal epithelial cells (Caco-2 cells) and the protective effect of eicosapentaenoic acid (EPA) after adherent-invasive Escherichia coli (E.coli) LF82 infection.

METHODSThe Caco-2 cell line was used to establish an in vitro model of tight junction of intestinal epithelial cells. Caco-2 cells were divided into EPA treatment groups (0, 25, 50, 100, and 200 μmol/L EPA) and EPA (0, 25, 50, 100, and 200 μmol/L EPA)+E.coli LF82 treatment (0, 6, and 12 hours) groups. A microscope was used to observe the morphological characteristics of the cells. MTT assay was used to determine the cell growth curve. The activity of alkaline phosphatase (ALP) at both sides of the cell membrane was compared to evaluate the Caco-2 cell model. MTT assay and flow cytometry were used to investigate the effects of different concentrations of EPA on the survival rate and apoptosis rate of Caco-2 cells. RT-qPCR was used to measure the mRNA expression of ZO-1 in Caco-2 cells after EPA and/or E.coli LF82 treatment. ELISA was used to measure the change in the level of tumor necrosis factor-α (TNF-α) in culture supernatant.

RESULTSAfter EPA treatment (25 and 50 μmol/L), the proliferation of Caco-2 cells was induced in a dose-dependent manner. The survival rates of the cells were significantly higher than those in the control group (P<0.05). The EPA treatment (100 and 200 μmol/L) groups had a significant inhibitory effect on the proliferation of Caco-2 cells in a dose-dependent manner. The survival rates of the cells were significantly lower than those in the control group (P<0.05). The EPA treatment (100 and 200 μmol/L) groups had a significant increase in cell apoptosis rate compared with the control group (P<0.05). The 6- and 12-hour E.coli LF82 treatment groups had decreasing mRNA expression of ZO-1 in Caco-2 cells over the time of treatment and had significantly lower mRNA expression of ZO-1 than the untreated group (P<0.05). The Caco-2 cells treated with E.coli LF82 and 25 or 50 μmol/L EPA for 6 or 12 hours showed an increase in the mRNA expression of ZO-1 with the increasing concentration of EPA, as well as significantly higher mRNA expression of ZO-1 than the Caco-2 cells treated with E.coli LF82 alone (P<0.05). The Caco-2 cells treated with E.coli LF82 alone for 6 or 12 hours had increasing secretion of TNF-α over the time of treatment and had significantly higher secretion than the untreated Caco-2 cells (P<0.05). The Caco-2 cells treated with E.coli LF82 and 25 or 50 μmol/L EPA for 6 or 12 hours showed a reduction in the secretion of TNF-α with the increasing concentration of EPA and had significantly lower secretion than the Caco-2 cells treated with E.coli LF82 alone (P<0.05).

CONCLUSIONSEPA can effectively prevent the destruction of tight junction of intestinal epithelial cells induced by E.coli LF82 infection and inhibit the secretion of inflammatory factors. Therefore, it has a certain protective effect on intestinal mucosal barrier.

Apoptosis ; drug effects ; Caco-2 Cells ; Eicosapentaenoic Acid ; pharmacology ; Escherichia coli ; pathogenicity ; Humans ; Intestinal Mucosa ; metabolism ; microbiology ; RNA, Messenger ; analysis ; Tight Junctions ; drug effects ; Tumor Necrosis Factor-alpha ; secretion ; Zonula Occludens-1 Protein ; genetics

This study aimed to provide evidence of persistent uropathogenic Escherichia coli (UPEC) in female patients with recurrent urinary tract infection (UTI) after antibiotic therapy. We collected biopsies of the bladder, and clean-catch urine samples from 32 women who had episodes of recurrent UTI and were given antibiotic therapy. Urine samples and biopsies were analyzed by conventional bacteriological techniques. Phylogenetic group and 16 virulence factors (VFs) of UPEC were determined using polymerase chain reaction (PCR). The infection capability of UPEC was confirmed in a mouse model. Immunofluorescence and electron microscopy were used to detect intracellular bacterial communities (IBCs) in the mouse model. The results showed that all urine specimens were detected sterile. E. coli was found in 6 of 32 biopsies (18.75%), and was identified to be UPEC by PCR. Different VFs associated with the formation of IBCs were identified in all six UPEC isolates. Each UPEC isolate was capable of forming IBCs within the bladder epithelial cells of mice. In conclusion, UPEC with distinctive pathological traits and the capability of IBC formation was first found in the bladders of women after antibiotic therapy, suggesting that the IBC pathogenic pathway may occur in humans and it plays an important role in UTI recurrence.
Adult ; Animals ; Anti-Bacterial Agents ; administration & dosage ; Biopsy ; Escherichia coli Infections ; drug therapy ; microbiology ; Female ; Humans ; Mice ; Middle Aged ; Phylogeny ; Urinary Bladder ; drug effects ; microbiology ; pathology ; Uropathogenic Escherichia coli ; drug effects ; genetics ; pathogenicity

BACKGROUNDAcute diarrhea remains the serious problem in developing countries, especially among children under 5 years of age. Currently, only two or three common diarrhea pathogens were screened at most hospitals in China. The aim of this study was to provide a wide variety of diarrhea pathogens and their antimicrobial resistance patterns in children under 5 years of age.

METHODSTotally 381 stool samples collected from Tongji Hospital between July 1, 2014 and June 30, 2015 were tested by culture and/or polymerase chain reaction for eight kinds of bacteria and five kinds of viruses. An antimicrobial sensitivity test was performed using dilution method recommended by the Clinical and Laboratory Standards Institute.

RESULTSViral infections were mainly identified in infants (0-11 months), whereas bacterial infections were more prevalent in the age of 24-59 months. About 69.8% of samples were positive for at least one pathogen, 51.7% of samples were virus positive, followed by bacteria positive cases (19.4%), and 12.6% of cases displayed co-infections with two viruses or a virus and a bacterium. Rotavirus was the most prevalent pathogen, followed closely by norovirus, while Salmonella was the most commonly isolated bacteria, followed by diarrheagenic Escherichia coli (DEC) and Campylobacter. More than 40% of Salmonella spp. and DEC isolates were resistant to first-line antibiotics (ampicillin, trimethoprim-sulfamethoxazole, and tetracycline). Around 10% of Salmonella spp. isolates were resistant to ceftriaxone and ciprofloxacin simultaneously. Campylobacter spp. displayed high resistance to ciprofloxacin but kept low resistance to azithromycin and doxycycline.

CONCLUSIONSThe etiology of acute diarrhea varies in children of different age groups. The high frequency of infection with viruses suggests the urgent demand for new viral vaccine development. Proper use of antibiotics in the treatment of acute diarrhea is crucial due to the high level of antibiotic resistance.

Acute Disease ; Anti-Bacterial Agents ; therapeutic use ; Azithromycin ; therapeutic use ; Campylobacter ; drug effects ; pathogenicity ; Child, Preschool ; China ; Ciprofloxacin ; therapeutic use ; Diarrhea ; drug therapy ; etiology ; microbiology ; virology ; Doxycycline ; therapeutic use ; Escherichia coli ; drug effects ; pathogenicity ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Salmonella ; drug effects ; pathogenicity

OBJECTIVETo investigate the effects of Lactobacillus rhamnosus GG (LGG) for inhibiting E.coli K1 (E44) adhesion and invasion of an intestinal epithelial cell model with Muc2 gene knockdown established using CRISPR-Cas9 system.

METHODSTwo 20-25 bp sgRNAs targeting Muc2 were chemically synthesized to construct CRISPR expression vectors for transfection in wild-type human colonic cancer cell line Ht29. The efficiency of Muc2 knockdown was determined using Western blotting. After assessment of the viability and proliferation of the transfected cells with MTT assay, we evaluated the effects of the probiotics against E44 adhesion and invasion of the cells through a competitive exclusion assay.

RESULTSTransfection of the cells with Lenticrisprv2 plasmid vectors resulted in a cell line with stable Muc2 knockdown by 81%. The inhibitory effects of probiotics against E44 adhesion and invasion of the transfected cells were markedly attenuated, and the relative adhesion and invasion rates of E44 were 72.23% (P<0.05) and 81.49% (P<0.05), respectively.

CONCLUSIONMuc2 knockdown causes attenuation of the inhibitory effects of probiotics against E44 adhesion and invasion of the intestinal epithelial cells, suggesting that up-regulation of Muc2 may serve as an important mechanism for the probiotics to reinforce the intestinal barrier and antagonize the pathogenic bacteria, which sheds light on a new strategy for prevention and treatment of bacterial intestinal infections.

Bacterial Adhesion ; CRISPR-Cas Systems ; Epithelial Cells ; cytology ; microbiology ; Escherichia coli ; pathogenicity ; Gene Knockdown Techniques ; HT29 Cells ; Humans ; Intestines ; cytology ; Lactobacillus rhamnosus ; Mucin-2 ; genetics ; Probiotics ; Transfection ; Up-Regulation

BACKGROUNDCommunity acquired pneumonia (CAP) is one of the most common infectious disease in emergency department. In 2005 the concept of healthcare associated pneumonia (HCAP) was proposed by the ATS/IDSA guidelines. The clinical features and microbiology of HCAP are different from CAP, however, the initial antimicrobial treatment is still controversial. We aimed to compare the clinical efficacy between HCAP patients treated initially with HCAP guideline-concordant antimicrobial agents and those with CAP guideline-concordant antimicrobial agents.

METHODSWe conducted a retrospective observational study on HCAP patients who were admitted to emergency department between December 2011 and December 2012. Patients were divided into 2 groups according to their different initial antimicrobial treatment. We compared clinical features, distribution of pathogen, severity, days and spending on intravenous antimicrobial, length and charge of hospitalization and clinical outcomes, and meanwhile analyzed the clinical efficacy as well.

RESULTSOf the 125 HCAP patients, 55 patients received CAP guideline-concordant antimicrobial agents and 70 received HCAP agents. The major pathogens were Klebsiella pneumoniae, methicillin-resistant staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Escherichia coli. The 2 groups were similar at baseline, including old age, comorbidities, Pneumonia Severity Index scores, APACHE scores, and length of intravenous antimicrobial use and hospitalization duration, and in-hospital mortality. Overall efficacy rate occurred in 70.0% of HCAP agent patients and 50.9% of CAP agent patients (P = 0.029). Antimicrobial charge and total hospital charge for HCAP agent patients were significantly higher than that for CAP agent patients.

CONCLUSIONSInitial treatment of HCAP patients in emergency department with HCAP guideline-concordant antimicrobial could increase clinical efficacy rate, as well as antimicrobial charge and total hospital charge, but was not associated with shortening the length of stay, or lowering in-hospital mortality.

Aged ; Aged, 80 and over ; Anti-Bacterial Agents ; pharmacology ; Emergency Service, Hospital ; Escherichia coli ; pathogenicity ; Female ; Humans ; Klebsiella pneumoniae ; pathogenicity ; Male ; Methicillin-Resistant Staphylococcus aureus ; pathogenicity ; Pneumonia ; drug therapy ; microbiology ; Pseudomonas aeruginosa ; drug effects ; Retrospective Studies

OBJECTIVETo study the role of outer membrane protein T (OmpT) in the pathogenesis of uropathogenic Escherichia.coli.

METHODSIn cultured human bladder epithelial cell line 5637, we examined the adhesion ability of wild-type (CFT073), ompT gene knockout (COTD), and revertant (pST) strains of E.coli to the cells and the extracellular matrix (ECM). The expressions of the adhesion gene iha and virulence gene iroN were detected by real-time PCR. Murine models of urinary tract infection with the 3 strains were established to evaluate the bacterial burden of the bladder and kidney tissue and bacterial counts in blood. We also detected the expressions of interleukin-6 (IL-6) and IL-8 in the bladder and kidney tissues of the mice.

RESULTThe COTD strain showed a significantly lower cell adhesion rate than CFT073 strain [(4.62∓0.39)% vs (8.81∓1.13)%, P<0.05] with also a lower ECM-adhesion rate [(4.95∓0.59)% vs (8.85∓0.79)%, P<0.05]. The mRNA expressions of iha and iroN in CFT073 strain were 2.1 and 3.8 times that of COTD strain. In the mouse model, the mean bacterial load of CFT073 strain in the bladder tissue was 6.36∓0.06, significantly greater than that of COTD (6.01∓0.07) and revertant (6.29∓0.06) strains (P<0.05); the bacterial load of CFT073 strain in the kidney tissue was also significantly higher than that of COTD strain (6.25∓0.05 vs 5.87∓0.06, P<0.05). In mice infected with the wild-type, knockout, and revertant strains, the detection rates of IL-6, which were identical to those of IL-8, in the inflammatory bladder and kidney tissues were 60%, 12.5%, and 50%, respectively.

CONCLUSIONSOmpT may regulate the expression of the adhesion gene iha and the transferrin gene iroN to affect the adhesion of uropathogenic E.coli to host cells.

Animals ; Bacterial Adhesion ; Bacterial Load ; Bacterial Outer Membrane Proteins ; metabolism ; Cell Line, Tumor ; Escherichia coli Infections ; pathology ; Escherichia coli Proteins ; metabolism ; Gene Knockout Techniques ; Humans ; Inflammation ; Interleukin-6 ; metabolism ; Interleukin-8 ; metabolism ; Kidney ; microbiology ; Mice ; Peptide Hydrolases ; metabolism ; Receptors, Cell Surface ; metabolism ; Urinary Bladder ; microbiology ; Urinary Tract Infections ; microbiology ; pathology ; Uropathogenic Escherichia coli ; pathogenicity

TcpC is a homolog of the Toll/interleukin-1 receptor (TIR) domain and is secreted by uropathogenic E. coli strain CFT073. TcpC can bind to MyD88, hereby exerting inhibitory effects on macrophages. TcpC represents an important virulence factor that promotes bacterial survival and pathogenicity. TcpC plays a critical role in urinary tract infection, particularly in the pathogenesis of pyelonephritis. In this review,the progress and prospects in TcpC research are discussed.
Animals ; Escherichia coli ; pathogenicity ; Escherichia coli Proteins ; physiology ; Humans ; Mice ; Pyelonephritis ; microbiology ; Urinary Tract Infections ; microbiology ; Virulence Factors ; physiology

Animals ; Anti-Bacterial Agents ; administration & dosage ; Escherichia coli ; Female ; Galactosylceramides ; immunology ; Gastric Mucosa ; pathology ; Gastritis, Atrophic ; pathology ; Helicobacter Infections ; complications ; drug therapy ; Helicobacter pylori ; pathogenicity ; Humans ; Inflammation ; pathology ; Intestines ; microbiology ; Levofloxacin ; Lymphocyte Activation ; Male ; Natural Killer T-Cells ; microbiology ; Ofloxacin ; administration & dosage ; Sphingomonas ; Stomach ; pathology