Prevalent Virulence Factors Research Articles

Detection of virulence factors and antimicrobial susceptibility pattern of clinically significant Klebsiella pneumoniae isolates in a tertiary care hospital

Introduction: Klebsiella pneumoniae is associated with a variety of infections across all age groups, both in community and hospital settings. Many strains of K. pneumoniae produce virulence factors such as a capsule, siderophores, biofilm, and hypermucoviscosity, which facilitate adhesion, invasion, and colonization. Additionally, the rising antibiotic resistance in K. pneumoniae strains poses a significant challenge, limiting treatment options. This study aims to identify the virulence factors and assess the antimicrobial susceptibility of clinically significant K. pneumoniae isolates. Materials and Methods: K. pneumoniae isolates were obtained from urine, sputum, blood, cerebrospinal fluid, pus swabs/aspirates, and tissue samples. Standard biochemical tests were performed for identification. Capsule formation, hypermucoviscosity, siderophore production, and biofilm formation were detected phenotypically. Antibiotic susceptibility testing was carried out using the disk diffusion method, and primary and confirmatory tests were conducted for extended-spectrum beta-lactamases (ESBL) and carbapenemase production. Results: Capsule formation, hypermucoviscosity, siderophore production, and biofilm formation were detected in 100%, 15%, 40%, and 15% of the isolates, respectively. Of the isolates, 40% were multidrug-resistant, 55% produced ESBL, 8% expressed AmpC beta-lactamase, and 10% produced carbapenemase. Conclusion: Capsule formation was the most prevalent virulence factor, followed by siderophore production. The majority of K. pneumoniae isolates demonstrated susceptibility to amikacin, piperacillin-tazobactam, and carbapenems. However, 40% of the isolates were multidrug-resistant, with ESBL production being the most common resistance mechanism.

Wastewater-based surveillance of Vibrio cholerae: Molecular insights on biofilm regulatory diguanylate cyclases, virulence factors and antibiotic resistance patterns

Vibrio cholerae is an inherent inhabitant of aquatic ecosystems. The Indian state of West Bengal, especially the Gangetic delta region is the highest cholera affected region and is considered as the hub of Asiatic cholera. V. cholerae were isolated from publicly accessible wastewater of Midnapore, West Bengal, India. Serotyping determined all isolates to be of non-O1/non-O139 serogroups. Moderate biofilm-forming abilities were noticed in most of the isolates (74.7 %) while, high biofilm formation was recorded for only 6.3 % isolates and 19 % of isolates exhibited low/non-biofilm-forming abilities. PCR-based screening of crucial diguanylate cyclases (DGCs) involved in cyclic-di-GMP-mediated biofilm signaling was performed. cdgH and cdgM were the most abundant DGCs among 93.7 % and 91.5 % of isolates, respectively. Other important DGCs, i.e., cdgK, cdgA, cdgL, and vpvC were present in 84 %, 75.5 %, 72 % and 68 % of isolates, respectively. Besides, the non-O1/non-O139 isolates were screened for the occurrence of virulence factor encoding genes. Moreover, among these non-O1/non-O139 isolates, two strains (3.17 %) harbored both ctxA and ctxB genes, which encode the cholera toxin associated with epidemic cholera. ompU was the most prevalent virulence factor, present in 24.8 % of isolates. Other virulence factors like, zot and st were found in 4.7 % and 9.5 % of isolates. Genes encoding tcp and ace were found to be PCR-negative for the isolates. Additionally, crucial virulence factor regulators, toxT, toxR and hapR were found to be PCR-positive in all the isolates. Antibiotic resistance patterns displayed further vulnerabilities with decreased sensitivity towards commonly used antibiotics with multiple antibiotic resistance index ranging between 0.37 and 0.62. The presence of cholera toxin-encoding multi-drug resistant (MDR) V. cholerae strains in environmental settings is alarming. High occurrence of DGCs are considered to encourage further investigations to use them as alternative therapeutic targets against MDR cholera pathogen due to their unique presence in bacterial systems.

Exploring virulence factors of Helicobacter pylori isolated from gastric biopsy.

Helicobacter pylori (H. pylori) colonizes human gastric mucosa and is classified as class one carcinogenic bacteria. In this regard, this study aimed to detect major virulence factors in H. pylori strains recovered from gastric biopsy in patients referred to Aras Clinique in Ardabil, northwest of Iran (2019-2021). In this descriptive-cross sectional study, 287 dyspeptic patients were included. For bacterial isolation, gastric biopsy specimens (n=287) were taken from gastric antrum, then aseptically were cultured on the selective medium and incubated at 37C in microaerophilic conditions for 3-5 days. 25.18% of all (n = 70) patients were found to be infected withH. pylori uponendoscopy. Of them, 9 patients (12.857%) and 2 patients (2.875%) had peptic ulcer disease and gastric cancer respectively. According to the different patterns of virulence factors, 57 virutypes were identified in which oipA-vacAs1-vacAm2 (3, 4.28% n =) and oipA-vacAs1-vacAs2-vacAm2 (3, 4.28% n =) were the most common patterns. The simultaneous presence of vacAS2, vacAm2 and hopQ2 genes was observed in both patients with gastric cancer. OipA (n = 562.5%), VacAs1 (n = 6.75%), VacAs2 (n = 6.75%), and VacAm2 (n = 787.5%) were found to be the most prevalent virulence factor. According previous studies, it is confirmed that the cagPAI gene cluster and vacA gene alleles are strongly correlated with gastritis and gastrointestinal tract adenocarcinomas. Our study indicated that 50% of the indigenous strains of H. pylori harbor these oncogenic genes and they are hypervirulent.

Presence of genes encoding aminoglycoside-modifying enzyme (AME) and virulence factors in high-level aminoglycoside-resistant (HLAR) Enterococcus strains isolated from retail chicken meat in Turkey

In this study, the presence of aminoglycoside-modifying enzyme (AME) and virulence factor genes were investigated in previously isolated 32 high-level aminoglycoside-resistant (HLAR) Enterococcus strains isolated from retail chicken meat in Turkey. At least one AME-encoding gene was detected in HLAR enterococci by polymerase chain reaction (PCR). The ant(6ʹ)-Ia was identified as the most prevalent (87.5%, 28/32) AME gene. The aph(3ʹ)-IIIa (78.13%, 25/32), ant(4ʹ)-Ia (68.75%, 22/32), aph(2ʹʹ)-Ib (62.5%, 20/32), aac(6ʹ)-Ie-aph(2ʹʹ)-Ia (21.88%, 7/32) and aph(2ʹʹ)-Ic (9.38%, 3/32) are the other detected AME-encoding genes in strains. The aph(2ʹʹ)-Id was found in none of the HLAR strains. The aph(2ʹʹ)-Ib and ant(6ʹ)-Ia were identified as the most frequently AME-encoding genes in high-level gentamicin-resistant (HLGR) and high-level streptomycin-resistant (HLSR) strains, respectively. Among the 32 HLAR strains, only E. faecalis MSE61.1 and E. avium MSE63.1 were found capable of hydrolyzing gelatine. All HLAR strains showed α-hemolytic activity except E. durans MG13.4 and E. casseliflavus MGM111.1, which were exhibited β- and γ-hemolytic activity, respectively. It was determined that all HLAR strains, except E. durans MGE13.1 and MGE63.1, contain at least one virulence factor gene. The efaAfm (87.5%, 28/32), acm (65.63%, 21/32) and gelE (37.5%, 12/32) were found to be the most prevalent virulence factor genes. HLAR enterococci strains that have the virulence factor genes may pose a risk to consumer health.

Proportion of toxin and non-toxin virulence factors of Staphylococcus aureus isolates from diabetic foot infection: a systematic review and meta-analysis

BackgroundStaphylococcus aureus isolates are the leading cause of diabetic foot infections (DFIs). Identification of specific virulence factors of S. aureus involved in the pathogenesis of DFIs may help control the infection more effectively. Since the most prevalent virulence factor genes are probably related to the DFI pathogenesis, the aim of this study is to evaluate the proportion of virulence factor genes of S. aureus isolates from DFIs.Materials and methodsWe conducted a systematic search of PubMed, Embase, Web of Science, and Scopus to identify all articles reporting the proportion of different types of virulence factors of S. aureus isolates from DFI samples.ResultsSeventeen studies were eligible, in which 1062 S. aureus isolates were obtained from 1948 patients and 2131 DFI samples. Among the toxin virulence factors, hld 100.0% (95% CI: 97.0, 100.0%), hlg 88.0% (95% CI: 58.0, 100.0%), hla 80.0% (95% CI: 31.0, 100.0%), hlgv 79.0% (95% CI: 35.0, 100.0%) and luk-ED 72.0% (95% CI: 42.0, 95.0%) had the highest proportion respectively. Among the genes associated with biofilm formation, both icaA and icaD had the highest proportion 100.0% (95% CI: 95.6, 100.0%).ConclusionThe results of the present study showed that among the toxin virulence factors, hemolysins (hld, hlg, hla, hlgv) and luk-ED and among the non-toxin virulence factors, icaA and icaD have the greatest proportion in S. aureus isolates from DFIs. These prevalent genes may have the potential to evaluate as virulence factors involved in DFI pathogenesis. Finding these probable virulence factor genes can help control diabetic foot infection more effectively via anti-virulence therapy or preparation of multi-epitope vaccines.

Widespread Detection of Yersiniabactin Gene Cluster and Its Encoding Integrative Conjugative Elements (ICEKp) among Nonoutbreak OXA-48-Producing Klebsiella pneumoniae Clinical Isolates from Spain and the Netherlands.

In this study, we determined the presence of virulence factors in nonoutbreak, high-risk clones and other isolates belonging to less common sequence types associated with the spread of OXA-48-producing Klebsiella pneumoniae clinical isolates from The Netherlands (n = 61) and Spain (n = 53). Most isolates shared a chromosomally encoded core of virulence factors, including the enterobactin gene cluster, fimbrial fim and mrk gene clusters, and urea metabolism genes (ureAD). We observed a high diversity of K-Locus and K/O loci combinations, KL17 and KL24 (both 16%), and the O1/O2v1 locus (51%) being the most prevalent in our study. The most prevalent accessory virulence factor was the yersiniabactin gene cluster (66.7%). We found seven yersiniabactin lineages-ybt 9, ybt 10, ybt 13, ybt 14, ybt 16, ybt 17, and ybt 27-which were chromosomally embedded in seven integrative conjugative elements (ICEKp): ICEKp3, ICEKp4, ICEKp2, ICEKp5, ICEKp12, ICEKp10, and ICEKp22, respectively. Multidrug-resistant lineages-ST11, ST101, and ST405-were associated with ybt 10/ICEKp4, ybt 9/ICEKp3, and ybt 27/ICEKp22, respectively. The fimbrial adhesin kpi operon (kpiABCDEFG) was predominant among ST14, ST15, and ST405 isolates, as well as the ferric uptake system kfuABC, which was also predominant among ST101 isolates. No convergence of hypervirulence and resistance was observed in this collection of OXA-48-producing K. pneumoniae clinical isolates. Nevertheless, two isolates, ST133 and ST792, were positive for the genotoxin colibactin gene cluster (ICEKp10). In this study, the integrative conjugative element, ICEKp, was the major vehicle for yersiniabactin and colibactin gene clusters spreading. IMPORTANCE Convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae isolates has been reported mostly related to sporadic cases or small outbreaks. Nevertheless, little is known about the real prevalence of carbapenem-resistant hypervirulent K. pneumoniae since these two phenomena are often separately studied. In this study, we gathered information on the virulent content of nonoutbreak, high-risk clones (i.e., ST11, ST15, and ST405) and other less common STs associated with the spread of OXA-48-producing K. pneumoniae clinical isolates. The study of virulence content in nonoutbreak isolates can help us to expand information on the genomic landscape of virulence factors in K. pneumoniae population by identifying virulence markers and their mechanisms of spread. Surveillance should focus not only on antimicrobial resistance but also on virulence characteristics to avoid the spread of multidrug and (hyper)virulent K. pneumoniae that may cause untreatable and more severe infections.

Analysis of Antibiotic-Resistant and Virulence Genes of Enterococcus Detected in Calf Colostrum-One Health Perspective.

Enterococci are considered among the most prevalent global multidrug-resistant microorganisms globally. Their dissemination is a global concern, particularly by food-producing animals for both animals and humans. The aim of this study was to identify the species and investigate the antibiotic resistance and virulence profile of Enterococcus in bovine colostrum. Out of 88 presumptive Enterococcus isolates, species identification and susceptibility to 14 antimicrobials were tested using the disk diffusion method. An analysis of the antibiotic resistance and virulence genes was performed on the most prevalent species, using specific PCR assays. Enterococcus faecalis (54.5%), E. faecium (14.8%) and E. gallinarum (6.8%) were the identified species. To the best of our knowledge, this is the first report of E. gallinarum in bovine colostrum. The majority of the isolates showed resistance to quinupristin-dalfopristin (95.9%), erythromycin (80.7%), tetracycline (80.7%) and streptomycin (58%). Ninety-two percent of isolates were classified as multidrug-resistant. The most frequently detected resistance genes were tet(K) (61.1%), tet(M) (75.9%), tet(L) (90.7%), erm(B) (55.6%) and ant(6)-Ia (46.3%). The most prevalent virulence factors were cpd, esp, agg and cylLL. Enterococcus faecium showed a higher probability of carrying the erm(C), tet(M), ace and gel(E) genes (p < 0.05). These results demonstrated that colostrum can constitute an important reservoir and vehicle for the dissemination of antibiotic resistance and virulence genes to the three niches included in a One Health perspective (humans, animals and the environment), highlighting the importance of hygiene sanitary measures to mitigate colostrum microbial contamination.

A statistical approach to identify prevalent virulence factors responsible for post-weaning diarrhoeic piglets

A statistical approach was carried out to identify the prevalent virulence factors responsible for post-weaning diarrhoea (PWD). Healthy piglets’ faecal samples and diarrhoeic piglets’ rectal swab specimens were secured. Twenty-six (26) and 100 independent enterotoxigenic Escherichia coli (ETEC) strains were subsequently isolated. These strains were assessed utilising polymerase chain reaction to identify the encoding genes of six virulence factors: heat-labile enterotoxin (LT; encoded by eltAB), heat-stable enterotoxin A (STa; encoded by estA), heat-stable enterotoxin B (STb; encoded by estB), enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1; encoded by astA), Shiga toxin 2e (Stx2e; encoded by stx2e), and F18 fimbriae (encoded by fedA). The LT and ST secretions were investigated using enzyme-linked immunosorbent assays. From direct observation, no stx2e was evident in the 126 strains. Among the 26 strains retrieved from the healthy piglets, none harboured fedA or secreted LT; 23% (6/26) secreted ST, and 50% (13/26) carried astA. A statistical regression was applied on the 100 E. coli strains retrieved from the diarrhoeic piglets, where fedA was set as the dependent variable and the enterotoxin secretions were set as the independent variables. The results exhibit that the LT secretion was the only significant factor (P &amp;lt; 0.000 1) correlated to fedA in the diarrhoeic piglets; thus, it is concluded that the prevalent virulence factors for PWD were the ECET strain with F18 fimbriae adhesion and LT secretion, but not astA or stx2e.

Sandwich-Based Immunosensor for Dual-Mode Detection of Pathogenic F17-Positive Escherichia coli Strains.

Bacterial diseases cause tremendous economic losses due to high morbidity and mortality in livestock animals. F17A protein, the major subunit of F17 fimbriae, is one of the most prevalent and crucial virulence factors among the pathogenic Escherichia coli (E. coli) isolated from diarrheic and septicemic animals of various species. Purification and detection of this protein is regarded as an interesting field of investigation due to its important role as a therapeutic target, such as vaccines, and as a diagnostic tool. In this context, polyclonal rabbit antibodies recognizing F17A protein (anti−F17A antibody) were developed and used for its detection. In fact, sandwich biosensor using anti−F17A/gold nanoparticles conjugates as capture probe and anti−F17A antibody labelled with horseradish peroxidase as signal amplification probe was developed for electrochemical and fluorescent detection of purified F17A protein and live F17–positive E. coli bacteria. Good specificity and sensitivity for detection of F17–positive E. coli strains were obtained. The dynamic range for the biosensor varies from 1 × 102 to 1 × 109 CFU·mL−1 (R2 = 0.998) and the detection limit (LOD) and the IC50 value were estimated to be 37 CFU·mL−1 and 75 CFU·mL−1, respectively.

Antibiotic resistance, phylogenetic typing, and virulence genes profile analysis of uropathogenic Escherichia coli isolated from patients in southern Iraq.

Of the most common infectious diseases that occur mainly by uropathogenic Escherichia coli (UPEC) is urinary tract infections (UTIs). The purpose of this study was to investigate virulence factors, antibiotic resistance, and phylogenetic groups among UPEC strains isolated from patients with UTI in southern Iraq. A total of 100 UPEC isolates were collected from urine samples of UTI patients from various hospitals in southern Iraq, and confirmed by morphological and biochemical tests. Antimicrobial susceptibility testing on isolates was performed by disk diffusion method. Multiplex PCR techniques were used to evaluate the phylogenetic groups based on Clermont method and to detect the presence of six virulence factor genes. The majority of isolates belonged to the phylogenetic groups B2 (46%) and C (13%). The most prevalent virulence factors were fimH (96%), followed by aer (47%), papC (36%), cnf1 (17%), hly (15%), and afa (8%). Phenotypic testing showed that the isolates were most resistant to piperacillin, ticarcillin, amoxicillin/clavulanic acid (92%, 91%, and 88%, respectively) and most sensitive to amikacin and imipenem, respectively. The maximum antibiotic resistance and virulence factors were observed in the phylogenetic group B2. The results showed that the UPEC isolates had all six virulence factors with high frequency and the highest drug resistance. Besides, the results showed a direct relationship between virulence factors, gene diversity, phylogenetic background, and antimicrobial resistance in the UPEC isolates.

Virulence Genes as Markers for Pseudomonas aeruginosa Biofilm Formation in Dogs and Cats

Simple SummaryPseudomonas aeruginosa is an opportunistic pathogen of dogs and cats able to cause both local and systemic infections. This bacterium is widespread in the environment, resistant to unfavorable conditions, and may spread between humans and other mammals. Its virulence and transmission rely on various virulence factors including those responsible for biofilm formation. Biofilm is defined as a complex biological system that is composed of exopolysaccharides, proteins, extracellular DNA, and biomolecules. Extracellular polymeric substances are the main ingredients of biofilm, accounting for 90% of its total biomass. In this study we analyzed the prevalence of five virulence genes involved in biofilm formation (pelA, pslA, ppyR, fliC and nan1) in 271 P. aeruginosa isolates obtained from dogs and cats. All animals had clinical symptoms of P. aeruginosa infection. In dogs, the strains were isolated from the external auditory canal, respiratory tract, and skin. In cats, the strains were isolated from the nasal cavity, external auditory canal, and skin. Biofilm-forming strains accounted for 90.6% of P. aeruginosa isolates from dogs and 86.4% from cats. The most commonly identified virulence factor gene was ppyR (97.4%). The fliC and pslA genes were detected in 62.4% and 60.1% of the study population, respectively, whereas nan1 and pelA genes were found in 45.0% and 38.7%, respectively. Prevalence of the virulence factor genes was not significantly different between dogs and cats. Given that the ability to form biofilm is related to the antibiotic resistance of P. aeruginosa, our results indicate potential candidates for biomarkers assisting in selection of the most effective treatment for P. aeruginosa infections.Pseudomonas aeruginosa is an ubiquitous bacterium and opportunistic pathogen that plays an important role in nosocomial infections. The presence of virulence factors and the biofilm-forming ability of this species contributes to a high risk of treatment complications. In this study, we examined the biofilm-forming ability and the prevalence of five virulence factor genes (pslA, pelA, ppyR, fliC, and nan1) in 271 P. aeruginosa isolates (212 from dogs and 59 from cats). Biofilm-forming ability was detected in 90.6% of isolates in dogs and 86.4% of isolates in cats. In P. aeruginosa isolates from both species, the most prevalent virulence factor gene was ppyR (97.2% in dogs and 98.3% in cats), followed by pslA (60.8% and 57.6%), fliC (60.4% and 69.5%), nan1 (45.3% and 44.1%), and pelA (40.1% and 33.9%, respectively). In dogs, a significantly higher proportion of biofilm-forming P. aeruginosa strains possessed the fliC gene compared to non-biofilm-forming strains (p = 0.015). In cats, a significantly lower proportion of biofilm-forming strains had the nan1 gene compared to non-biofilm-forming strains (p = 0.017). In conclusion, the presence of fliC gene and the absence of nan1 gene could be indicators of biofilm-forming ability of P. aeruginosa.

Salivary Microbiome in Adenoid Cystic Carcinoma Detected by 16S rRNA Sequencing and Shotgun Metagenomics.

Microorganisms are confirmed to be closely related to the occurrence and development of cancers in human beings. However, there has been no published report detailing relationships between the oral microbiota and salivary adenoid cystic carcinoma (SACC). In this study, unstimulated saliva was collected from 13 SACC patients and 10 healthy controls. The microbial diversities, compositions and functions were comprehensively analyzed after 16S rRNA sequencing and whole-genome shotgun metagenomic sequencing. The alpha diversity showed no significant difference between SACC patients and healthy controls, while beta diversity showed a separation trend. The SACC patients showed higher abundances of Streptococcus and Rothia, while Prevotella and Alloprevotella were more abundant in healthy controls. The prevalent KEGG pathways, carbohydrate-active enzymes, antibiotic resistances and virulence factors as well as the biomarkers in SACC were determined by functional gene analysis. Our study preliminarily investigated the salivary microbiome of SACC patients compared with healthy controls and might be the basis for further studies on novel diagnostic and treatment strategies.

Characterisation of Clostridium perfringens isolated from chickens in Vietnam

The objective of this study was isolating and characterising Clostridium perfringens from chickens in Vietnam and identifying virulence factors involved with enteritis. Five hundred thirty-one faecal and sixty-eight intestinal samples were collected from healthy and diseased chickens for the C. perfringens isolation. The presence of virulence factors was determined by multiplex PCR. The netB gene of the selected isolates was sequenced and checked for its expression by SDS-PAGE. Two hundred seventy-two C. perfringens isolates were collected. All of them were shown to be positive for the cpa gene. The netB gene was detected in 26.56% of the C. perfringens isolates from the healthy chickens, while 43.45% of the isolates from the faeces and 45% of the isolates from the intestinal samples were positive for this gene in the diseased birds. All eight isolates positive to netB from the diseased chickens showed 100% identity in the netB sequence and produced the NetB toxin in vitro, whereas only two out of eight healthy chicken-derived isolates produced this toxin. Nine out of ten chickens experimentally infected with the C. perfringens netB-positive isolate showed typical signs of enteritis. The cpa gene was the most prevalent virulence factor identified in the bacteria C. perfringens, but the netB gene could be a major player responsible for necrotic enteritis progression in chickens.

Characterization of Shiga-toxin producing Escherichia coli (STEC) isolated from retail raw meats in Southeast China

Shiga toxin-producing Escherichia coli (STEC) is an important zoonotic foodborne pathogen that can induce acute gastrointestinal symptoms related to human infection. In this study, we characterized 49 STEC strains isolated from 816 retail raw meats from 2010 to 2016 in Southeast China for their serotype, virulence-associated genes, phylogenetic group, antibiotic resistance, and biofilm-forming ability. These isolates belonged to 33 divergent O: H serotypes, among which O157: H7 (12.24%, 6/49) was the most common serotype. Moreover, 22.45% (11/49) isolates belonged to the “top six” serotypes most frequently implicated in human infections. Among the 11 virulence-associated genes studied, stx2 (71.43%, 35/49) was the most prevalent virulence factor, with 87.76% (43/49) of isolates carrying two or more types of virulence factors. The B1 (55.10%, 27/49) and D (28.57%, 14/49) phylogenetic groups were predominant among isolates, whereas no strain belonged to group B2. A total of 59.18% (29/49) of isolates were resistant to 13 out of 16 tested antimicrobials, with resistance rate ranging from 4.08% (2/49) for both ceftazidime and chloramphenicol to 46.94% (23/49) for streptomycin. We detected eight out of 30 antibiotic-resistance genes (tetA, tetB, strA, strB, gyrA, floR, sulI, and sulII), with obvious mismatch between the phenotypes and genotypes of these isolates. Most strains (87.76%, 43/49) produced biofilms and 23.26% (10/43) were categorized as high producers. In conclusion, raw meats retailed in Southeast China contain STEC with multifarious serotypes, virulence-associated genes, antimicrobial resistance and biofilm-forming ability, some of which pose potential health risks to consumers.

Broad-Spectrum Cephalosporin-Resistant and/or Fluoroquinolone-Resistant Enterobacterales Associated with Canine and Feline Urogenital Infections.

The aim of the present study was to characterize Enterobacterales resistant to 3rd and 4th generation cephalosporins, carbapenems and/or fluoroquinolones, isolated from dogs and cats with urogenital infections. In total, 36 strains (Escherichia coli (n = 28), Klebsiella pneumoniae (n = 3), Serratia marcescens, Raoultella ornithinolytica, Proteus mirabilis, Citrobacter portucalensis and Enterobacter cloacae (each n = 1)) were included in the present study, 28 from Austria and 8 from Serbia. Isolates were characterized by a polyphasic approach including susceptibility pheno- and genotyping and microarray-based assays. Escherichia (E.) coli isolates were additionally characterized by two-locus (fumC and fimH) sequence phylotyping and multi-locus sequence typing (MLST) of selected isolates. MLST of carbapenem-resistant Enterobacter cloacae isolates was also performed. Among E. coli, the most dominant phylogenetic group was B1 (27.8%), followed by C, (16.6%), A and Clade II (5.5% each), B2 and F (2.77% each). The most predominant β-lactam resistance genes were blaTEM (70%) and blaCTX-M (38.8%), blaCMY (25%). blaNDM was detected in one carbapenem-resistant Enterobacter cloacae ST114. The most common ST among selected E. coli was 744 (10.7% isolates). The pandemic clones ST131 and ST648 carrying CTX-M-15 were also detected. Remaining STs belonged to 469, 1287, 1463 and 1642. E. coli clonotyping revealed 20 CH types. Based on the presence of certain virulence genes, three isolates were categorized as ExPEC/UPEC. The most prevalent virulence factors were fimH detected in 61%, iucD and iss both in 55%, iroN in 27.8%, papC in 13.8% and sat in 8.3% isolates.

A DNA Sequence Analysis of Helicobacter pylori in Jeddah City, Western Saudi Arabia

Helicobacter pylori are the type of Gram-negative bacteria which colonize the mucous lining of the human stomach. These bacteria have two major virulence factors: (vacuolating cytotoxin A gene) and (cytotoxin-associated A gene). This study aimed to provide data to determine the prevalent virulence factors (vacA and cagA genes) in Jeddah city, western Saudi Arabia, by sequence analysis. This study included 60 patients with symptoms similar to H. pylori infection. H. pylori were identified by using the 16s rRNA sequence. Then, the screening for specific genes in H. pylori (vacA and cagA) was done by using automated DNA sequencing analysis, and the DNA sequences were compared by BLAST and sequence alignment of the vacA nucleotides that are present in all H. pylori strains using those already reported in GeneBank from various studies. Results indicated that H. pylori infection was detected in 13.3%, while 86.7% were negative samples in our study patients. Interestingly, the vacA gene was found in 8.3%, while the cagA gene was not appear in patient. Also, the female prevalence rate was higher than males (11.7% female versus 1.7% males), and the highest infection was between age 40-49 by 6.7%. In conclusion, this study revealed that the vacA gene was spread in the patients infected with H. pylori in Jeddah, while the cagA gene was not appear in any isolate.

A retrospective study on Escherichia coli bacteremia in immunocompromised patients: Microbiological features, clinical characteristics, and risk factors for shock and death.

BackgroundTo evaluate clinical features, bacterial characteristics, and risk factors for shock and mortality of immunocompromised patients with Escherichia coli bacteremia.MethodsA nearly 6‐year retrospective study of E coli bacteremia in 188 immunocompromised patients at Xiangya Hospital was conducted. Demographic, clinical, and laboratory data were documented. Phylogenetic background and virulence factors of E coli isolates were detected by polymerase chain reaction. Risk factors for shock and mortality were also investigated.ResultsOf all 188 E coli isolates, most prevalent virulence factors were fimH (91.0%), followed by traT (68.6%) and iutA (67.0%), while papG allele I, gafD, and cdtB were not detected. Phylogenetic group D was dominant (42.0%) among all isolates, and group B2 accounted for 17.6%, while group A and B1 accounted for 28.2% and 12.2%, respectively. In univariate analysis, ibeA and cnf1 were associated with mortality, which were not found in multivariate regression analysis. 22.3% of patients suffered shock, and 30‐day mortality rate was 21.3%. MDR (HR 2.956; 95% CI, 1.091‐8.012) was the only risk factor for shock, while adult (HR 0.239; 95% CI, 0.108‐0.527) was a protective factor. Multivariate analysis revealed that shock (HR 4.268; 95% CI, 2.208‐8.248; P < .001) and Charlson index > 2 (HR 2.073; 95% CI, 1.087‐3.952; P = .027) were associated with fatal outcome.Conclusions Escherichia coli bacteremia was highly lethal in immunocompromised patients, and host‐related factors played major roles in poor prognosis, while bacterial determinants had little effect on outcome. This study also provided additional information about the virulence and phylogenetic group characteristics of E coli bacteremia.

&lt;p&gt;Characterization of antibiotic resistance and virulence factors of &lt;em&gt;Escherichia coli&lt;/em&gt; strains isolated from Iranian inpatients with urinary tract infections&lt;/p&gt;

BackgroundUrinary tract infections (UTIs) are one of the most frequent human infectious diseases causing considerable amount of morbidity and mortality. The present study aimed to investigate the occurrence of antibiotics resistance and virulence genes among Escherichia coli strains isolated from UTIs in the north of Iran.MethodsThis cross-sectional study was performed at 5 teaching hospitals in Rasht in the north of Iran. Totally, 129 E. coli isolates were identified by standard microbiologic tests. Antimicrobial susceptibility pattern was determined using disk diffusion method. The presence of virulence genes was detected by PCR method.ResultsThe results of antibiotic susceptibility showed that the highest resistance rates were to ampicillin (78.3%) followed by nalidixic acid (74.4%) and trimethoprim/sulfamethoxazole (69.8%). On the other hand, the highest susceptibility was toward nitrofurantoin (96.1%) and imipenem (92.2%). Further analysis revealed that the rate of ESBL-producing and multiple-drug resistant isolates was 51.2% and 84.5%, respectively. Molecular analysis revealed that traaT (87.6%) gene was the most prevalent virulence factors followed by fyuA (86%) and kpsmt (76%) genes. Also, fimH gene was the most frequently detected adhesion-associated gene with 74.4%.ConclusionIn summary, our results showed a remarkable rate of drug resistance and heterogeneity for virulence factors among E. coli strains isolated from UTIs in the north of Iran. The emergence of such strains can be a predictive marker for their persistence in the hospital and consequently a significant threat for hospitalized patients.

Extra-intestinal pathogenic Escherichia coli from human and avian origin: Detection of the most common virulence-encoding genes.

Pathogenic Escherichia coli strains cause a wide range of extra intestinal infections including urinary tract infection in humans and colibacillosis in poultry. They are classified into uropathogenic E. coli (UPEC) and avian pathogenic E. coli (APEC) with genetic similarities and variations. Their pathogenicity is related to the virulence-encoding genes like sfa, papG II, ompT, iutA, and iss with zoonotic potentials. One hundred isolated E. coli from patients with urinary tract infection and 100 E. coli from chickens with colibacillosis were evaluated for the presence of the most common virulence-encoding genes including sfa, papG II, ompT, iutA, and iss by multiplex polymerase chain reaction. While the frequency of sfa, papG II, ompT, iutA and iss encoding genes in APEC isolates were respectively 0.00%, 67.00%, 63.00%, 89.00% and 89.00%, the frequency of these encoding genes in UPEC isolates were 18.00%, 40.00%, 40.00%, 74.00% and 48.00%, respectively. Except for sfa, the frequencies of other encoding genes in APEC were more than those in UPEC isolates. The iutA as the most common UPEC encoding gene and iss as the most common APEC encoding gene were the most prevalent virulence factors in the examined E. coli isolates. Finding out the distribution of virulence-associated genes could be helpful to identify similarities and differences between APEC and UPEC isolates in order to provide more substantial evidence of their common virulence traits and potential zoonotic threats.

Characterization of Vaginal Escherichia coli Isolated from Pregnant Women in Two Different African Sites

The relevance of vaginal colonization of pregnant women by Escherichia coli is poorly understood, despite these strains sharing a similar virulence profile with other extraintestinal pathogenic E. coli producing severe obstetric and neonatal infections. We characterized the epidemiology, antimicrobial susceptibility and virulence profiles of 84 vaginal E. coli isolates from pregnant women from Rabat (Morocco) and Manhiça (Mozambique), two very distinct epidemiological settings. Low levels of antimicrobial resistance were observed to all drugs tested, except for trimethoprim-sulfamethoxazole in Manhiça, where this drug is extensively used as prophylaxis for opportunistic HIV infections. The most prevalent virulence factors were related to iron acquisition systems. Phylogroup A was the most common in Rabat, while phylogroups E and non-typeable were the most frequent in Manhiça. Regardless of the apparently “low virulence” of these isolates, the frequency of infections is higher and the outcomes more devastating in constrained-resources conditions, especially among pregnant women and newborns.