Pathogenic Enteric Bacteria Research Articles

PREVALENCE OF PATHOGENIC ENTERIC BACTERIA ASSOCIATED WITH DIARRHOEA IN CHILDREN OF UNDER FIVE YEARS AND THEIR SENSITIVITY TO ANTIBIOTICS IN UNGUJA ISLAND, ZANZIBAR

Background: Diarrhoea is an important cause of morbidity and mortality among children in developing countries and resistance of bacteria is a global problem.Objective: The present study in Unguja Island, Zanzibar, aimed at determining the prevalence and identity of pathogenic enteric bacteria associated with diarrhoea in children under five years and to assess the resistance of these bacteria to antibiotics.Methodology: A cross sectional quantitative study was conducted, a total of 319 stool samples were collected. The prevalence and identity of pathogenic enteric bacteria were determined through conventional methods and antimicrobial resistance by the Kirby-Bauer antibiotic testing method.Results: The prevalence isolates were; Shigella spp. In 41.5%, Salmonella spp.(29.3%), Vibrio parahaemolyticus(13.1%) and pathogenic E. coli (16.2%). Pathogenic enteric bacteria were commonly more resistant to sulfamethoxazole/trimethoprim, Erythromycin, Tetracycline and Ampicillin but were less resistant to Ciproflaxin, Gentamycin, and Chloramphenicol respectively.Conclusion: The results indicated that the prevalence of pathogenic enteric bacteria was high and often they were resistant to antibiotics commonly used to treat diarrhoea in children under five years in Zanzibar. We therefore recommend reviewing of guidelines for treatment of childhood diarrhoea, promote health education, scale up vaccination campaign and regulate the use of antimicrobials to prevent further development of antibiotic resistance.

Distribution of potentially pathogenic bacteria in the groundwater of the Jianghan Plain, central China

Pathogenic bacteria are frequently detected in groundwater. However, little is known about the abundance and diversity of potentially pathogenic bacteria and their influencing factors in the groundwater of the Jianghan Plain (JHP), one of the most densely habited areas in central China. Here, we investigated the diversity and abundance of potentially pathogenic bacteria in 156 groundwater samples collected from one 400 km2 area of the JHP by using 16S rRNA-based Illumina sequencing and quantitative PCR. A total of 193 potentially pathogenic bacterial species were identified in the studied groundwater. Phylogenetic results showed that opportunistic pathogenic Acinetobacter baumannii -like and enteric pathogenic Vibrio cholerae-like bacteria were most prevalent, occurring in 99% and 32% of the studied groundwater samples, respectively. Spatial factors contributed more (5.5% vs 2.4%) than the measured environmental factors to shaping of the potentially pathogenic bacterial distribution, although a large proportion (92.0%) of variation was unexplained. The groundwater temperature was the most important measured factor influencing the abundances of the identified potentially pathogenic bacterial species. In addition, certain opportunistic pathogenic bacterial species showed statistically significant co-occurrence in the studied JHP groundwater samples. Collectively, this data of this study provide new insight into the diversity, distribution and influencing factors of potential pathogens in the JHP groundwater.

Analysis of bacterial etiology of the outpatients with infectious diarrhea in the Children′s Hospital Capital Institute of Pediatrics

Objective To analyze the bacterial etiology and drug resistance of pathogens from the outpatients with acute infectious diarrhea in the Children′s Hospital Capital Institute of Pediatrics. Methods The children with acute infectious diarrhea in the outpatient department of our hospital were randomly enrolled in the period of August 2017 to July 2018. Enteric pathogenic bacteria were cultured and isolated from the fresh stool specimens. The serum of Salmonella spp were identified while five types of diarrheagenic Escherichia coli were detected by PCR method. Antibiotic susceptibility of Salmonella spp and diarrheagenic Escherichia coli were tested by Kirby-Bauer disk diffusion method.Chi-square or Fisher exact test was done for statistical analysis. Results Of the 356 stool specimens, 103 strains of 6 pathogenic bacterial species were detected. The positive rate was 27.8% (99/356), and 2 strains were detected in four stool samples. The isolation rate of Salmonella spp, which was the highest in this study, was 10.7% (38/356). The isolation rate of Staphylococcus aureus, diarrheagenic Escherichia coli and Pseudomonas aeruginosa were 8.4% (30/356), 5.6% (20/356) and 3.7% (13/356), respectively. No Shigella spp strain was isolated. Salmonella enteritidis and Salmonella typhimurium were the dominant serotype for 38 Salmonella spp stains with the isolation rate of 63.2% (24/38). Each 10 Enteropathogenic Escherichia coli and 10 Enteroaggregative Escherichia coli isolates were detected among the diarrheagenic Escherichia coli. Enterohemorrhagic Escherichia coli, Enteroinvasive Escherichia coli and Enterotoxigenic Escherichia colistrain was not found in this study. The resistant rates of Salmonella spp to ampicillin and ceftriaxone were 52.6% (20/38) and 13.2% (5/38), while the diarrheagenic Escherichia coli were 11/20 and 1/20, respectively. Three diarrheagenic Escherichia coli isolates produced extended spectrum beta-lactamase. Conclusions Salmonella spp was the major bacterial pathogen among the outpatients with infectious diarrhea in the hospital. The study indicated that the infection ratios of Staphylococcus aureus, diarrheagenic Escherichia coli and Pseudomonas aeruginosa increased. Shigella spp was no long the main pathogenic agent. The resistant rates of Salmonella spp and diarrheagenic Escherichia coli to ampicillin were high, but low resistant rates to ceftriaxone were found among these two kinds of bacteria. The third-generation cephalosporins should be the first choice for the treatment of childhood bacterial diarrhea. Key words: Diarrhea; Salmonella; Escherichia coli; Drug resistance,Bacterial; Child

Salmonella, Campylobacter, Clostridium difficile, and anti-microbial resistant Escherichia coli in the faeces of sympatric meso-mammals in southern Ontario, Canada.

The role of free-ranging wildlife in the epidemiology of enteropathogens causing clinical illness in humans and domestic animals is unclear. Salmonella enterica and anti-microbial resistant bacteria have been detected in the faeces of raccoons (Procyon lotor), but little is known about the carriage of these bacteria in other sympatric meso-mammals. Our objectives were to: (a) report the prevalence of Salmonella and associated anti-microbial resistance, Campylobacter spp, Clostridium difficile, and anti-microbial resistant Escherichia coli in the faeces of striped skunks (Mephitis mephitis) and Virginia opossums (Didelphis virginiana) in southern Ontario; and (b) compare the prevalence of these bacteria in the faeces of these meso-mammal hosts with raccoons from a previously reported study. Faecal swabs were collected from striped skunks and Virginia opossums on five swine farms and five conservation areas from 2011 to 2013. Salmonella was detected in 41% (9/22) and 5% (5/95) of faecal swabs from Virginia opossums and striped skunks, respectively. None of the Salmonella serovars carried resistance to anti-microbials. The prevalence of Campylobacterspp., C.difficile, and anti-microbial resistant E.coli ranged from 6% to 22% in striped skunk and Virginia opossums. Using exact logistic regression, Salmonella was significantly more likely to be detected in faecal swabs of Virginia opossums than skunks and significantly less likely in faecal swabs from skunks than raccoons from a previously reported study. In addition, Campylobacter spp. wassignificantly more likely to be detected in raccoons than opossums. Salmonella Give was detected in 8/9 (89%) of Salmonella-positive Virginia opossum faecal swabs. Our results suggest that striped skunks and Virginia opossums have the potential to carry pathogenic enteric bacteria in their faeces. The high prevalence of Salmonella Give in Virginia opossum faecal swabs in this study as well as its common occurrence in other Virginia opossum studies throughout North America suggests Virginia opossums may be reservoirs of this serovar.

An Outbreak of Gastroenteritis Associated with GII.17 Norovirus-Contaminated Secondary Water Supply System in Wuhan, China, 2017

A gastroenteritis outbreak occurred in a university in May, 2017, Wuhan, China. The epidemiological survey and pathogen analysis were conducted to identify the pathogen and control this outbreak. Feces or anal swabs from individuals, water, and swabs taken from tap surfaces of the secondary water supply system (SWSS) and foods were collected for the detection of viruses and pathogenic enteric bacteria by real-time RT-PCR and culture, respectively. Nucleotide sequences were determined by RT-PCR and direct sequencing. Genotyping, phylogenetic, and recombination analyses were conducted by a web-based genotyping tool, MEGA, and RDP4 programs, respectively. Of 144 individuals enrolled, 75 met the case definitions. The epidemic curve showed one peak of incidence suggesting the most probable spread of a single common source. In total, 33 specimens were collected before disinfection of the SWSS. Of these, norovirus was detected and identified as GII.P17-GII.17 with 100% nucleotide sequence identity among the strains detected in ten students (10/14), a maintenance worker (1/2) dealing with the SWSS, four water samples (4/8), and two swabs taken from tap surfaces (2/3). Pathogens including Vibrio cholerae, Salmonella, Shigella, Vibrio parahaemolyticus, Bacillus cereus, enteropathogenic Escherichia coli, rotavirus, astrovirus, and sapovirus were negative. The GII.17 strains in this outbreak clustered closely in the same branch of the phylogenetic tree, and slightly apart from the strains of other cities in China, neighboring countries and regions, European and American countries. This gastroenteritis outbreak was deduced to be attributed to GII.P17-GII.17 norovirus contamination of the SWSS.

Molecular Characterization of Enterobacter and Escherichia coli Pathotypes Prevalent in the Popular Street Foods of Dhaka City and their Multidrug Resistance

Food borne pathogenic enteric bacteria are of great concern for global public health. Among them, Escherichia coli and Enterobacter spp. are the most prevalent in the street food. In this study, 23 strains of such enteric bacteria were isolated from multiple food samples by conventional cultural technique. Isolated strains were characterized molecularly into different genotypes using RAPD, amplified ribosomal DNA restriction analysis, and partial sequencing of 16S rDNA. RAPD represents 10 different types of strains whereas ARDRA clusters them into two separate groups. 16 out of the 23 isolates were identified as E. coli and the rest were as Enterobacter spp. by biochemical tests and were further confirmed by partial 16S rDNA sequencing. Significant level of virulence traits including stx1, stx2 and escV genes were identified in E. coli strains. Also, most of the isolates were found resistant to azithromycin and amoxicillin. This study revealed the presence of various pathogenic enteric bacteria in various street foods with multidrug resistance. Therefore, this study suggests that people consuming such street foods are at major risk of food borne illness.
 Bangladesh J Microbiol, Volume 34 Number 2 December 2017, pp 67-72

Draft Genome Sequences of 72 Isolates from All Four Species of Shigella.

Shigella is a genus of Gram-negative enteric pathogenic bacteria which has four species, Shigella dysenteriae, S. flexneri, S. boydii, and S. sonnei. Shigella species are clinically important bacteria because they cause shigellosis or dysentery. Here we report the genome sequences of 72 Shigella isolates from these four species.

Can probiotics be an alternative to chlorhexidine for oral care in the mechanically ventilated patient? A multicentre, prospective, randomised controlled open trial

BackgroundPathogenic enteric bacteria aspirated from the oropharynx are the main cause of ventilator-associated pneumonia (VAP). Using chlorhexidine (CHX) orally or selective decontamination has been shown to reduce VAP. In a pilot study we found that oral care with the probiotic bacterium Lactobacillus plantarum 299 (Lp299) was as effective as CHX in reducing enteric bacteria in the oropharynx. To confirm those results, in this expanded study with an identical protocol we increased the number of patients and participating centres.MethodsOne hundred and fifty critically ill patients on mechanical ventilation were randomised to oral care with either standard 0.1% CHX solution (control group) or a procedure comprising final application of an emulsion of Lp299. Samples for microbiological analyses were taken from the oropharynx and trachea at inclusion and subsequently at defined intervals.Student’s t test was used for comparisons of parameters recorded daily and Fisher’s exact test was used to compare the results of microbiological cultures.ResultsPotentially pathogenic enteric bacteria not present at inclusion were identified in oropharyngeal samples from 29 patients in the CHX group and in 31 samples in the probiotic group. Considering cultures of tracheal secretions, enteric bacteria were found in 17 and 19 samples, respectively. Risk ratios show a difference in favour of the Lp group for fungi in oropharyngeal cultures. VAP was diagnosed in seven patients in the Lp group and in 10 patients among the controls.ConclusionsIn this multicentre study, we could not demonstrate any difference between Lp299 and CHX used in oral care procedures regarding their impact on colonisation with emerging potentially pathogenic enteric bacteria in the oropharynx and trachea.Trial registrationClinicalTrials.gov, NCT01105819. Registered on 9 April 2010.First part: Current Controlled Trials, ISRCTN00472141. Registered on 22 November 2007 (published Critical Care 2008, 12:R136).

Characterization of a Salmonella Enteritidis bacteriophage showing broad lytic activity against Gram-negative enteric bacteria.

In this study, we sought to isolate Salmonella Enteritidis-specific lytic bacteriophages (phages), and we found a lytic phage that could lyse not only S. Enteritidis but also other Gramnegative foodborne pathogens. This lytic phage, SS3e, could lyse almost all tested Salmonella enterica serovars as well as other enteric pathogenic bacteria including Escherichia coli, Shigella sonnei, Enterobacter cloacae, and Serratia marcescens. This SS3e phage has an icosahedral head and a long tail, indicating belong to the Siphoviridae. The genome was 40,793 base pairs, containing 58 theoretically determined open reading frames (ORFs). Among the 58 ORFs, ORF49, and ORF25 showed high sequence similarity with tail spike protein and lysozyme-like protein of Salmonella phage SE2, respectively, which are critical proteins recognizing and lysing host bacteria. Unlike SE2 phage whose host restricted to Salmonella enterica serovars Enteritidis and Gallinarum, SS3e showed broader host specificity against Gram-negative enteric bacteria; thus, it could be a promising candidate for the phage utilization against various Gram-negative bacterial infection including foodborne pathogens.

Keragaman Bakteri Enterik Patogen Siput Felle (Angulyagra tricostata) dari Pesisir Danau Sentani Kabupaten Jayapura

Felle Snails (Angulyagra tricostata) is an alternative source of animal protein for the people around Sentani Lake. Meat of Felle snails has an indication of being contaminated by pathogenic enteric bacteria harmful to the health of the public consumption. The purpose of this study was to determine the diversity of bacterial enteric pathogens in Felle snails (A. tricostata) from the coast of Sentani Lake, Jayapura. Felle snails were taken from various points near existing residential areas around the coastal region of Sentani Lake. Extraction of meats Snail dilutions was made prior to planting in stages up to 10-10. Each serial dilution of 0.1 mL were taken and inoculated into Lactose Broth medium (LB), Mac Conkey Media (MC) agar and media EMBA at 370C for 24 hours. Colonies that grew were sub-cultured to get different colonies and grown on agar slant. Identification of individual characters was performed by colony fenetik numerical methods. The result indicated that there were seven selected isolates and the dendrogram showed that those species were similar to four of genus Enterobacteriaceae. Seven isolates consisted of 2 isolates similar to the genus Escherchiae, 2 isolates similar to Klebsiellae, 2 isolates similar to the genus Salmonellae and 1 isolate similar to the genus Shigellae. Similarity index value of each  selected isolates ranged from 69 to 86%.Key words: Felle snail, bacterial enteric pathogens, Enterobacteriaceae, and sentani lake.

Occurrence of Bacterial Pathogens and Human Noroviruses in Shellfish-Harvesting Areas and Their Catchments in France.

During a 2-year study, the presence of human pathogenic bacteria and noroviruses was investigated in shellfish, seawater and/or surface sediments collected from three French coastal shellfish-harvesting areas as well as in freshwaters from the corresponding upstream catchments. Bacteria isolated from these samples were further analyzed. Escherichia coli isolates classified into the phylogenetic groups B2, or D and enterococci from Enterococcus faecalis and E. faecium species were tested for the presence of virulence genes and for antimicrobial susceptibility. Salmonella members were serotyped and the most abundant serovars (Typhimurium and its monophasic variants and Mbandaka) were genetically characterized by high discriminative subtyping methods. Campylobacter and Vibrio were identified at the species level, and haemolysin-producing Vibrio parahaemolyticus were searched by tdh- and trh- gene detection. Main results showed a low prevalence of Salmonella in shellfish samples where only members of S. Mbandaka were found. Campylobacter were more frequently isolated than Salmonella and a different distribution of Campylobacter species was observed in shellfish compared to rivers, strongly suggesting possible additional inputs of bacteria. Statistical associations between enteric bacteria, human noroviruses (HuNoVs) and concentration of fecal indicator bacteria revealed that the presence of Salmonella was correlated with that of Campylobacter jejuni and/or C. coli as well as to E. coli concentration. A positive correlation was also found between the presence of C. lari and the detection of HuNoVs. This study highlights the importance of simultaneous detection and characterization of enteric and marine pathogenic bacteria and human noroviruses not only in shellfish but also in catchment waters for a hazard assessment associated with microbial contamination of shellfish.

The impact of municipal sewage sludge stabilization processes on the abundance, field persistence, and transmission of antibiotic resistant bacteria and antibiotic resistance genes to vegetables at harvest

Biosolids were obtained from four Ontario municipalities that vary in how the sewage sludge is treated. These included a Class B biosolids that was anaerobically digested, a Class A biosolids that were heat treated and pelletized (Propell), and two Class A biosolids that were stabilized using either the N-Viro (N-Rich) or Lystek (LysteGro) processes. Viable enteric indicator or pathogenic bacteria in the biosolids were enumerated by plate count, gene targets associated with antibiotic resistance or horizontal gene transfer were detected by PCR, and a subset of these gene targets were quantified by qPCR. Following application at commercial rates to field plots, the persistence of enteric bacteria and gene targets in soil was followed during the growing season. Carrots, radishes and lettuce were sown into the amended and unamended control plots, and the diversity and abundance of gene targets they carried at harvest determined. All three Class A biosolids carried fewer and less abundant antibiotic resistance genes than did the Class B biosolids, in particular the very alkaline N-Viro product (N-Rich). Following application, some gene targets (e.g. int1, sul1, strA/B, aadA) that are typically associated with mobile gene cassettes remained detectable throughout the growing season, whereas others (e.g. ermB, ermF, blaOXA20) that are not associated with cassettes became undetectable within three weeks or less. At harvest a larger number of gene targets were detected on the carrots and radishes than in the lettuce. Overall, land application of Class A biosolids will entrain fewer viable bacteria and genes associated with antibiotic resistance into crop ground than will amendment with Class B biosolids.

Contribution of NRF2 in Gastrointestinal Protection from Oxidative Injury.

The human gastrointestinal tract is exposed to a variety of toxic agents, such as Helicobacter pylori (H.pylori), Nonsteroidal Anti-inflammatory Drugs (NSAIDs), gastric acid, enteric pathogenic bacteria, excessive auto immune reactions, and chronic mental stresses. These stressors generate free radicals within the gastrointestinal tissues, causing chronic inflammatory diseases, ulcers, cancers, and functional disturbances. Recent studies have demonstrated that some natural food compounds upregulate the nuclear factor erythroid 2-related factor 2- mediated antioxidant system, ameliorating or preventing these disorders. We have previously shown that dietary intake of sulforaphane-rich broccoli sprouts, ameliorates gastric inflammation induced by H. pylori, prevents NSAIDs-induced small intestinal injury, and improve functional constipation. There have been many other compounds, which enhance the nuclear factor erythroid 2-related factor 2-mediated antioxidant system, sufficient evidence for their clinical efficacy has not yet been provided. In addition, we have to pay attention to some reports, which have shown that excessive stimulation of nuclear factor erythroid 2-related factor 2 enhance chemoresistance and facilitates growth of cancer cells.

Characteristics of Gorilla-Specific Lactobacillus Isolated from Captive and Wild Gorillas.

Lactic acid bacteria (LAB) reside in a wide range of mammals, such as autochthonous intestinal bacteria. In this paper, we present the phenotypic and phylogenetic characteristics of gorilla-specific LAB. Lactobacillus gorillae—previously isolated from the wild and captive western lowland gorillas (Gorilla gorilla gorilla)—were successfully isolated from wild mountain gorillas (Gorilla gorilla beringei) in addition to other captive and wild western lowland gorillas. The strains from wild gorillas could ferment D-xylose, arbutine, cellobiose, and trehalose better than those from captive gorillas. By contrast, tolerance to NaCl was higher in isolates from captive gorillas than in those from wild gorillas. This tendency may have been induced by regular foods in zoos, which contain sufficient amount of salts but less amount of indigestible fiber and plant secondary metabolites compared to foods in the wild. All strains of L. gorillae showed inhibitory activities to enteric pathogenic bacteria; however, the activity was significantly higher for strains from wild gorillas than for those from captive gorillas. This may have been induced by the captive condition with routine veterinary intervention. Since L. gorillae can grow in the gastrointestinal tract of gorillas in captivity, the strains from wild mountain gorillas are potential probiotics for gorillas under captive conditions.

Evaluation of the activity of disinfectants against coliform bacteria group strains isolated from a sewage treatment plant (ETE-Ipanema)

Municipal wastewater usually presents pathogenic enteric bacteria, viruses and intestinal parasites. Primary, secondary and tertiary wastewater treatment eliminates 90-99.9% of these microorganisms and if a more efficient reduction of microorganisms is needed, disinfection with chemical compounds must be done. The extraordinary genetic variability of bacteria gives them adaptation ability against theses chemical agents, which indiscriminate use brings about serious health problems. In this study, chemical agents commonly used in disinfection procedures like chlorhexidine gluconate, sodium hypochlorite and quaternary ammonium compounds were investigated for their activity against bacteria from the coliform group, isolated from a sewage treatment plant, using the macrodilution method. It was observed that the addition of organic matter interferes in sensitivity levels and also that the lower the concentration and the exposure time, the higher the resistance. Sodium hypochlorite was the most effective against the coliforms, once inhibited their growth in every exposure time and at every disinfectant concentration used . Quaternary ammonium compounds and chlorhexidine gluconate were also effective, although a higher percentage of resistance was observed for both.

Relationship between Enteric Pathogen and Acute Gastroenteritis Disease Severity: A Prospective Cohort Study

Background: Acute gastroenteritis is one of the top reasons children are brought for emergency department care. Little is known about the association between specific pathogens and disease severity in children with vomiting/diarrhea in the outpatient setting. Recent advances in diagnostic approaches enabling the simultaneous detection of common pathogenic enteric bacteria, viruses, and parasites have become readily available. Clinicians can request testing be performed to rapidly and comprehensively identify etiologic pathogens. While such knowledge can be used to optimize therapy, it also has the potential to predict disease severity. Such knowledge can aid clinical …

Autochthonous lactic acid bacteria isolated from pig faeces in Thailand show probiotic properties and antibacterial activity against enteric pathogenic bacteria

Lactic acid bacteria (LAB) play an important role in pig health and performance that arises from their beneficial impacts on the balance of gastrointestinal microbes, ability to fight enteric pathogens, and capacity to support the immune system. The aim of this study was to evaluate the functional and safety aspects of five previously isolated autochthonous LAB strains, (Lactobacillus plantarum 22F, 25F and 31F, Pediococcus acidilactici 72N and Pediococcus pentosaceus 77F) from pig faeces as potential probiotics for a pig feed supplement. The functional and safety properties of the strains were assessed by in vitro tests. The functional properties tested were their abilities in tolerating low pH values under simulated gastric conditions, their cell surface properties (hydrophobicity, auto- and co-aggregation), antibacterial activity against the common enteric pathogenic bacteria in pigs (such as pathogenic Escherichia coli, Salmonella Choleraesuis and Streptococcus suis), and diacetyl production. The safety of the strains was analyzed based on the absent of haemolysis on blood and bile salt hydrolase activity. Although all strains demonstrated diacetyl production, good survivability and antibacterial activities, L. plantarum 22F and 25F showed the best performance with the strongest antibacterial actions against the indicator pathogens. Of the strains, only P. pentosaceus 77F exhibited haemolysis or bile salt hydrolase activity. Furthermore, a principal component analysis revealed that L. plantarum 22F possessed superior functional and safety aspects compared to the other four autochthonous strains and to reference strains L. plantarum JCM 1149 and P. acidilactici DSM 20284. Further in vivo studies using oral administration of the strains are justified to assess their effectiveness as feed supplements for pigs.

Genomic characterization of key bacteriophages to formulate the potential biocontrol agent to combat enteric pathogenic bacteria.

Combating bacterial pathogens has become a global concern especially when the antibiotics and chemical agents are failing to control the spread due to its resistance. Bacteriophages act as a safe biocontrol agent by selectively lysing the bacterial pathogens without affecting the natural beneficial microflora. The present study describes the screening of prominent enteric pathogens NDK1, NDK2, NDK3, and NDK4 (Escherichia, Klebsiella, Enterobacter, and Serratia) mostly observed in domestic wastewater; against which KNP1, KNP2, KNP3, and KNP4 phages were isolated. To analyze their potential role in eradicating enteric pathogens and toxicity issue, these bacteriophages were sequenced using next-generation sequencing and characterized based on its genomic content. The isolated bacteriophages were homologous to Escherichia phage (KNP1), Klebsiella phage (KNP2), Enterobacter phage (KNP3), Serratia phage (KNP4), and belonged to Myoviridae family of Caudovirales except for the unclassified KNP4 phage. Draft genome analysis revealed the presence of lytic enzymes such as holing and lysozyme in KNP1 phage, endolysin in KNP2 phage, and endopeptidase with holin in KNP3 phage. The absence of any lysogenic and virulent genes makes this bacteriophage suitable candidate for preparation of phage cocktail to combat the pathogens present in wastewater. However, KNP4 contained a virulent gene rendering it unsuitable to be used as a biocontrol agent. These findings make the phages (KNP1-KNP3) as a promising alternative for the biocontrol of pathogens in wastewater which is the main culprit to spread these dominated pathogens in different natural water bodies. This study also necessitates for genomic screening of bacteriophages for lysogenic and virulence genes prior to itsuse as a biocontrol agent.

Rapid visual detection of Mycobacterium avium subsp. paratuberculosis by recombinase polymerase amplification combined with a lateral flow dipstick.

Paratuberculosis (Johne's disease) is a chronic debilitating disease of domestic and wild ruminants. However, widespread point-of-care testing is infrequent due to the lack of a robust method. The isothermal recombinase polymerase amplification (RPA) technique has applied for rapid diagnosis. Herein, RPA combined with a lateral flow dipstick (LFD) assay was developed to estimate DNA from Mycobacterium avium subsp. paratuberculosis. First, analytical specificity and sensitivity of the RPA-nfo primer and probe sets were assessed. The assay successfully detected M. paratuberculosis DNA in 30 min at 39℃ with a detection limit of up to eight copies per reaction, which was equivalent to that of the real-time quantitative polymerase chain reaction (qPCR) assay. The assay was specific, as it did not amplify genomes from five other Mycobacterium spp. or five pathogenic enteric bacteria. Six hundred-twelve clinical samples (320 fecal and 292 serum) were assessed by RPA-LFD, qPCR, and enzyme-linked immunosorbent assay, respectively. The RPA-LFD assay yielded 100% sensitivity, 97.63% specificity, and 98.44% concordance rate with the qPCR results. This is the first report utilizing an RPA-LFD assay to visualize and rapidly detect M. paratuberculosis. Our results show this assay should be a useful method for the diagnosis of paratuberculosis in resource-constrained settings.

Surveillance and drug resistance analysis of thermotolerant Escherichia coli in sewage from hospitals in Shaoxing

Objective To analyze the drug resistance and detect the drug resistance genes of pathogenic bacteria isolated from hospital sewage, and to investigate the sources of antibiotic resistant microorganisms in the environment. Methods The enteric pathogenic bacteria, such as thermotolerant Escherichia coli, Salmonella and Shigella, were isolated from the sewage of Shaoxing hospitals from January 2016 to December 2016, and the detection of drug resistance of thermotolerant Escherichia coli, the drug resistance of Escherichia coli isolated from clinical specimens of three hospitals was compared and analyzed. Meanwhile, extended spectrum beta lactamases (ESBLs) resistance genes were detected in thermotolerant Escherichia coli in sewage. Results 48 strains of pathogens were isolated in sewage, including 32 strains of Escherichia coli, 2 strains of Shigella sonnei and 1 strain of Salmonella arizonae. Escherichia coli has a low rate of resistance to most antibiotics. Compared to Escherichia coli isolated from clinical specimens, there were significant differences among the drug resistance rates of Ampicillin, Aztreonam, Amoxicillin/Clavulanic acid and the first to four generation Cephalosporins (P<0.05). 11 strains of ESBLs positive bacteria were detected in sewage. Among them, 7 carried CTX-M9 resistance genes, and 4 carried TEM resistance genes, while 1 strain of CTX-M1 and SHV was carried. There were 2 strains carrying CTX-M9 and TEM resistance genes simultaneously, 1 strain simultaneously carrying TEM and SHV resistance genes. Conclusions There are different kinds of intestinal pathogens in hospital sewage, which may lead to contamination of drug-resistant microorganisms in the environment. Therefore the hospitals should strengthen the quality of sewage treatment and improve the qualified rate of sewage disinfection. Key words: Hospital sewage; Microorganism; Survey; Drug resistance; Thermotolerant Escherichia coli