The 2016 Global Burden of Disease report by WHO revealed that diseases of the gastrointestinal tract (GIT) had one of the highest incidence rates worldwide. The plethora of factors that contribute to the development of GIT-related illnesses can be divided into genetic, environmental and lifestyle factors. Apart from that, the role that infectious agents play in the development of GIT diseases has piqued the interest of researchers worldwide. The human gut harbors approximately 1014 bacteria in it with increasing concentration toward the lower GIT. Among the various microbiota that colonize the human gut, Gram-negative bacteria have been most notoriously linked to GIT-related diseases such as inflammatory bowel disease (IBD) including Crohn's disease and ulcerative colitis and colorectal cancer (CRC). Some of the notable culprits that have been attributed to these diseases are Bacteroides fragilis, Fusobacterium nucleatum, Escherichia coli and Helicobacter pylori. However, studies in recent years are beginning to recognize a new player, Klebsiella pneumoniae (K. pneumoniae) in the causation and progression of GIT diseases. Once synonymous with infections and diseases of the upper respiratory tract, K. pneumoniae has now emerged as one of the pathogens commonly isolated from patients with GIT diseases. However, extensive studies attributing K. pneumoniae to GIT diseases, particularly that of CRC are scanty. Therefore, this review intends to shed light on the association of K. pneumoniae in gastrointestinal diseases such as Crohn's disease, ulcerative colitis as well as CRC.
Although non-sporulating molds (NSM) are frequently isolated from patients and have been recognized as agents of pulmonary disease, their clinical significance in cutaneous specimens is relatively unknown. Therefore, this study aimed to identify NSM and to determine the keratinolytic activity of isolates from cutaneous sites. NSM isolates from clinical specimens such as skin, nail, and body fluids were identified based on their ribosomal DNA sequences. Of 17 NSM isolates (7 Ascomycota, 10 Basidiomycota), eleven were identified to species level while five were identified to the genus level. These include Schizophyllum commune, a known human pathogen, Phoma multirostrata, a plant pathogen, and Perenniporia tephropora, a saprophyte. To determine fungal pathogenicity, keratinolytic activity, a major virulence factor, was evaluated ex vivo using human nail samples by measuring dye release from keratin azure, for NSM along with pathogens (Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis and Fusarium spp.) and nonpathogenic (endophyte) fungi for comparison. This study showed that pathogenic fungi had the highest keratinolytic activity (7.13 ± 0.552 keratinase units) while the nonpathogenic endophytes had the lowest activity (2.37 ± 0.262 keratinase units). Keratinolytic activity of two Ascomycota NSM (Guignardia mangiferae and Hypoxylon sp.) and one Basidiomycota NSM (Fomitopsis cf. meliae) was equivalent to that of pathogenic fungi, while Xylaria feejeensis showed significantly higher activity (p
This study aimed to investigate antibiotic resistance and putative virulence factors among Cronobacter sakazakii isolated from powdered infant formula and other sources. The following 9 cultures (CR1-9) were collected from our culture collection: C. sakazakii and 3 Cronobacter species: C. sakazakii ATCC® 29544™, C. muytjensii ATCC® 51329™, C. turicensis E866 were used in this study. Isolates were subjected to antibiotic susceptibility and the following virulence factors (protease, DNase, haemolysin, gelatinase, motility and biofilm formation) using phenotypic methods. All the bacteria were able to form biofilm on agar at 37 °C and were resistant to ampicillin, erythromycin, fosfomycin and sulphamethoxazole. It was observed from this study that tested strains formed weak and strong biofilm with violet dry and rough (rdar), brown dry and rough (bdar), red mucoid and smooth (rmas) colony morphotypes on Congo red agar. Rdar expresses curli and fimbriae, while bdar expresses curli. Both biofilm colony morphotypes are commonly found in Enterobacteriaceae including Salmonella species. This study also reveals a new colony morphotypes in Cronobacter species. Conclusively, there was correlation between putative virulence factors and antibiotic resistance among the tested bacteria. Further study on virulence and antibiotic resistance genes is hereby encouraged.
Little is known about the evolution, adaptation and pathogenesis of Burkholderia pseudomallei within host during acute melioidosis infection. Melioidosis is a potential life threatening disease contracted through inhalation, ingestion, inoculation or direct entry of the organism into the blood stream via wounds or skin abrasions from contaminated soil and water. Environmental B. pseudomallei strain (Bp MARAN ), isolated during a melioidosis outbreak in Pahang, Malaysia was injected intra-peritoneally into a mouse and passaged strain was recovered from spleen (Bpmouse-adapted). A gel-based comparative proteomics profiling approach was used, to map and identify differentially expressed proteins (fold-change ≥ 2; p-value ≤ 0.05) between the strains. A total of 730 and 685 spots were visualised in the Bp MARAN and Bpmouse-adapted strains, respectively. Of the 730 spots (Bp MARAN as reference gel), 87 spots were differentially regulated (44 up- and 43 down-regulated). The identified proteins were classified as proteins related to metabolism, stress response, virulence, signal transduction, or adhesion. In comparison, it was found that those proteins related to adhesins, virulence factors and stress- response were up-regulated and could possibly explain the adaptation of the bacteria in the host. Investigating the differentially expressed proteins may provide better perspective of bacterial factors which aid survivability of B. pseudomallei in host.
Local Thai and imported Malaysian beef in southern Thailand area carry several Shiga toxin-producing Escherichia coli (STEC) serotypes. STEC O104 is an important pathogen capable of causing outbreaks with considerable morbidity and mortality. This study investigated the presence of E. coli O104 from local Thai and imported Malaysian beef obtained from markets in Hat Yai City, Songkhla Province during August 2015 - February 2016. Thirty-one E. coli O104 strains were isolated from 12 beef samples (16% and 23% Thai and imported Malaysian, respectively). Thirty strains possessed aggA (coding for a major component of AAF/I fimbriae), a gene associated with enteroaggregative E. coli (EAEC) pathotype, and all strains carried fimH (encoding Type 1 fimbriae). Thirty strains belonged to phylogenetic group B1 and one strain (from Malaysian beef) to group A. Agglutination of yeast cells was observed among 29 E. coli O104 strains. Investigation of stx2 phage occupancy loci demonstrated that sbcB was occupied in 12 strains. Antimicrobial susceptibility assay revealed that 7 strains were resistant to at least one antimicrobial agent and two were multi-drug resistant. One strain carried extended spectrum β-lactamase gene blaCTX-M and three carried blaTEM. PFGE-generated DNA profiling showed identical DNA pattern between that of one EAEC O104 strain from Thai beef and another from Malaysian beef, indicating that these two strains originated from the same clone. This is the first report in Thailand describing the presence of EAEC O104 from both Thai and imported Malaysian beef and their transfer between both countries. Thorough surveillance of this pathogen in fresh meats and vegetables should help to prevent any possible outbreak of E. coli O104.
Outer inflammatory protein A (OipA) is an important virulence factor associated with gastric cancer and ulcer development; however, the results have not been well established and turned out to be controversial. This study aims to elucidate the role of OipA in Helicobacter pylori infection using clinical strains harbouring oipA "on" and "off" motifs. Proteomics analysis was performed on AGS cell pre-infection and postinfection with H. pylori oipA "on" and "off" strains, using liquid chromatography/mass spectrometry. AGS apoptosis and cell cycle assays were performed. Moreover, expression of vacuolating cytotoxin A (VacA) was screened using Western blotting. AGS proteins that have been suggested previously to play a role or associated with gastric disease were down-regulated postinfection with oipA "off" strains comparing to oipA "on" strains. Furthermore, oipA "off" and ΔoipA cause higher level of AGS cells apoptosis and G0/G1 cell-cycle arrest than oipA "on" strains. Interestingly, deletion of oipA increased bacterial VacA production. The capability of H. pylori to induce apoptosis and suppress expression of proteins having roles in human disease in the absence of oipA suggests that strains not expressing OipA may be less virulent or may even be protective against carcinogenesis compared those expressing OipA. This potentially explains the higher incidence of gastric cancer in East Asia where oipA "on" strains predominates.