Virulence Genes In Isolates Research Articles

Isolation, identification, antibiotic resistance profile and molecular analysis of Ornithobacterium rhinotracheal isolates from turkeys.

Ornithobacterium rhinotracheal (ORT) infects numerous birds, particularly chickens and turkeys. ORT is an emerging bacterial pathogen of global concern in the poultry industry. As ORT is rapidly spreading throughout commercial poultry, it requires intensive studies of its epidemiology, diagnostic procedures, molecular typing, virulence genes and antimicrobial resistance. The present study was conducted in isolation and identification of ORT from slaughtered turkeys. Cleft palate swabs of 200 were collected from slaughtered turkeys and cultured on blood agar. ORT was characterized using biochemical tests and PCR targeting the ORT 16S rRNA gene. Virulence genes of isolates were determined targeting adenylate kinase (adk), copA and virulence-associated protein D (vapD) genes. Additionally, diversity of ORT isolates was performed by enterobacterial repetitive intergenic consensus (ERIC) and RAPD PCR. Disk diffusion was used to determine the antibiotic sensitivity of the isolates. ORT was identified in 23 (11.5%) samples using both the biochemical tests and PCR. The result of detecting virulence genes showed that all the isolates (23: 100%) had the adk gene, whereas two (8.7%) isolates had the copA gene, and seven (30.43%) isolates had the vapD gene. Molecular typing of isolates revealed 21 different patterns by RAPD PCR assay using M13 primer and 20 distinct patterns by ERIC PCR test. Both ERIC and RAPD PCR were distinctive methods for investigating the genetic diversity of ORT isolates. The antibiotic resistance test showed that 18 (78.26%) isolates were resistant to gentamicin, amikacin, cefazolin, streptomycin and penicillin. All isolates (100%) were resistant to cloxacillin and fosfomycin. This study showed the prevalence of ORT in turkey and high resistance of this bacterium to many common veterinary antibiotics. Moreover, both ERIC and RAPD PCR are distinctive methods for investigating the genetic diversity of ORT isolates. These data may help monitor antibiotic resistance and typing of ORT in epidemiological studies and serve as the foundation for designing region-specific vaccines for future use.

Potential antivirulence activity of sub-inhibitory concentrations of ciprofloxacin against Proteus mirabilis isolates: an in-vitro and in-vivo study.

Proteus mirabilis is a significant nosocomial pathogen that is frequently associated with a wide range ofinfections, necessitating heightened attention to mitigate potential health risks. Hence, this study was performed to investigate the impact of sub-minimum inhibitory concentrations (MICs) of ciprofloxacin (CIP) on Proteus mirabilis clinical isolates. The sub-MICs of CIP were selected using the growth curve approach. The untreated and treated isolates with sub-MICs of CIP were assessed for their biofilm development, motilities on agar, and other virulence factors. The cell morphology of untreated and treated isolates with sub-MIC of CIP was explored using electron microscope. Moreover, the expression levels of the virulence genes in isolates were measured using quantitative real-time PCR. Data revealed that sub-MICs of CIP significantly (p < 0.05), in a concentration-dependent manner, inhibited biofilm formation and other virulence factors in the selected isolates. Electron microscope analysis showed cell enlargement and various abnormalities in the cell wall and membrane integrity. Sub-MICs of CIP exhibited inhibition of virulence and alterations in morphological integrity against P. mirabilis isolates.

Frequency of Some Important Exotoxin Genes in Pseudomonas aeruginosa Samples Isolated from Bovine Mastitis in Tabriz City in 2022

Background: Pseudomonas aeruginosa is an important opportunistic pathogen resulting in treatment-resistant subclinical mastitis in dairy cows. Examination of the frequency of some important virulence genes in isolates from bovine mastitis can be necessary for better management and recognition of infections caused by this bacterium. Objectives: This study was conducted on the frequency of some important exotoxin genes in P. aeruginosa samples derived from bovine mastitis in the city of Tabriz in 2022. Methods: This study was performed with 120 bacterial samples of P. aeruginosa that were isolated from clinical samples of bovine mastitis and were considered to investigate the frequency of some important exotoxin genes. Bacterial DNA was extracted, and the presence of exotoxin A, T, and U genes in P. aeruginosa samples was found by PCR method. Results: The frequency of exotoxin A, T, and U genes in P. aeruginosa samples was 18 (15%), 32 (26.6%), and 26 (21.6%), respectively, and 8 (6.6%) P. aeruginosa samples possessed all 3 intended genes simultaneously; while 76 (63.3%) P. aeruginosa samples lacked the tested genes. Conclusions: A relatively high frequency of exotoxin genes studied can be a serious warning to treat and control the bovine mastitis caused by this bacterium.

Detection of Virulence Genes Stx1, Stx2, eae A and hly A in E.coli Isolated from Local Minced Meat

The current study included the investigation of E. coli bacteria in random samples of ground meat, the detection of virulence genes in isolates, and the study of isolates resistance to some widely used antibiotics. Twenty-four samples of minced meat were collected to isolate and identify E. coli bacteria by phenotypic, microscopic characteristics and traditional biochemical tests were done. Antibiotic susceptibility tests, genomes of isolates were extracted, the virulence factors Stx1, Stx2, eae A and hly A were investigated by multiplex PCR technique. 7 isolates showed Colonies with a metallic green luster on EMB medium, gram negative, rod shaped bacteria, facultative anaerobic bacteria, positive for indole, methyl red and catalase tests, and negative for Fox Proscore, urease and oxidase tests. All isolates were containing hly A gene, 6 isolates were containing the virulence gene Stx1, 5 isolates containing were eae A gene and 4 isolates were containing Stx2 gene. The results shown a high resistance of E. coli isolates to all types of antibiotics used, as all isolates were possessed multiple antibiotic resistance.

Identification of faecal Escherichia coli isolates with similar patterns of virulence and antimicrobial resistance genes in dogs and their owners.

The presence of antimicrobial resistance and virulence genes in Escherichia coli allows them to survive and cause infections. The close contact between humans and pets can reinforce the risk of transmitting resistant and virulent bacteria between them. This study aims to compare the patterns of the presence of tetracycline and streptomycin resistance genes, as well as important virulence genes in E. coli isolated from faeces of healthy dogs and their owners. Polymerase chain reactions were performed for detection of antimicrobial resistance (tetA, tetB, tetC, tetD, strA and strB) and virulence (fimH, iss, sitA and malX) genes in 144 faecal E. coli isolates from 28 dog-owner pairs and 16 humans who did not keep any pets as controls. Among the investigated antimicrobial resistance and virulence genes, tetA (52.1%) and fimH (86.8%) genes had the highest prevalence. No statistically significant difference was found between the prevalence of antimicrobial resistance and virulence genes in isolates of dogs and their owners. In total, 46.4% of dog-owner pairs had the same patterns of presence or absence of six antimicrobial resistance genes, 50.0% had the same patterns of presence or absence of four virulence genes and 25.0% had the same patterns of presence or absence of all 10 tested genes. The presence of antimicrobial-resistant virulent E. coli in humans and pets may predispose them to infections that are hard to cure with conventional antibiotics. Notable frequency of dogs' and their owners' E. coli isolates with similar patterns of antimicrobial resistance and virulence genes may indicate the possibility of sharing virulent antimicrobial resistant E. coli between them.

Comparative Analysis of Clinical and Genomic Characteristics of Hypervirulent Klebsiella pneumoniae from Hospital and Community Settings: Experience from a Tertiary Healthcare Center in India.

ABSTRACTHypervirulent Klebsiella pneumoniae (hvKp) is a hypermucoviscous phenotype of classical Klebsiella pneumoniae (cKp) that causes serious infections in the community. The recent emergence of multidrug-resistant hvKp isolates (producing extended-spectrum beta-lactamases and carbapenemases) along with other virulence factors in health care settings has become a clinical crisis. Here, we aimed to compare the distribution of virulence determinants and antimicrobial resistance (AMR) genes in relation to various sequence types (STs) among the clinical hvKp isolates from both settings, to reinforce our understanding of their epidemiology and pathogenic potential. A total of 120 K. pneumoniae isolates confirmed by matrix-assisted laser desorption ionization–time of flight mass spectrometry were selected. hvKp was phenotypically identified by string test and genotypically confirmed by the presence of the iucA gene using PCR. Molecular characterization of hvKp isolates was done by whole-genome sequencing (WGS). Of the K. pneumoniae isolates, 11.6% (14/120) isolates were confirmed as hvKp by PCR (9.1% [11/120] string positive and 3.3% [4/120] positive by both methods); these were predominantly isolated from bloodstream infection (50%, 7/14), urinary tract infection (29%, 4/14), and respiratory tract infection (21%, 3/14). For all 14 hvKp infections, for 14.2% the source was in the community and for 85.7% the source was a health care setting. Two virulent plasmids were identified by WGS among the hvKp isolates from both settings. K64 was found to be the commonest capsular serotype (28.5%, 4/14), and ST2096 was the most common ST (28.5%, 4/14) by WGS. Two new STs were revealed: ST231 (reported to cause outbreaks) and ST43. The genome of one isolate was determined to be carrying AMR genes (blaCTX-M-15, blaNDM-1, blaNDM-5, blaOXA-181, blaOXA-232, etc.) in addition to virulence genes, highlighting the clonal spread of hvKp in both community and health care settings.IMPORTANCE To date, studies comparing the genomic characteristics of hospital- and community-acquired hvKp were very few in India. In this study, we analyzed the clinical and genomic characteristics of hvKp isolates from hospital and community settings. ST2096 was found as the most common ST along with novel STs ST231 and ST43. Our study also revealed the genome is simultaneously carrying AMR as well as virulence genes in isolates from both settings, highlighting the emergence of MDR hvKp STs integrated with virulence genes in both community and health care settings. Thus, hvKp may present a serious global threat, and essential steps are needed to prevent its further dissemination.

Molecular Detection of Listeria Monocytogenes in Milk and Some Milk Products

Listeria monocytogenes is considered one of the major potential foodborne pathogens which often threaten human health and life. Our study assessed both existence and virulence of L. monocytogenes in raw milk and different milk byproducts in Damietta Governorate, Egypt. One hundred and fifty random samples of raw milk, Kariesh cheese, Domiati cheese, Roomi cheese, yogurt and cream (twenty-five samples for each) were gathered from small retails and various supermarkets at for isolation of L. monocytogenes as well as direct detection of the pathogen in the samples’ using PCR technique that targeting 16S rRNA. Also, the study aimed to investigate the presence of virulence genes; (hly A, inl A, inl B, prf A, plc A) in L. monocytogenes isolates. The PCR findings for direct detection of L. monocytogenes declared that 41 out 150 examined samples were positive to 16S rRNA meanwhile by culture methods L. monocytogenes was recovered from 36 out of 150 examined samples. With regard to detection of virulence genes in isolates, 100% of the isolates (36) harbor inl A gene while 35 isolate (97.2%) harbor hly A gene. It was found that 100% of the samples (41) that were positive to 16S rRNA were also found positive to hly A and inl A genes. plcA gene was not detected in all samples whether directly or in isolates. inlB was detected in 8 out of 41 (19.5%) positive samples directly detected while it was detected in 15 out of 36 (41.6%) of isolates. prfA gene was detected in 25 out of 41 (60.9%) positive samples while it was detected in 20 out of 36 (55.5%) of isolates. Our study revealed that the considerable high isolation of L. monocytogenes among examined raw milk and its byproducts constitutes a potential public health hazard. Usually, PCR is seen as important technique for precise diagnosis of microorganisms rather than the classical cultural methods.

Antimicrobial Susceptibility Profiles and Molecular Characterisation of Staphylococcus aureus from Pigs and Workers at Farms and Abattoirs in Zambia.

Pigs have been shown to be a reservoir for recently emerging livestock-associated Staphylococcus aureus (LA-SA), including methicillin resistant strains in many countries worldwide. However, there is sparse information about LA-SA strains circulating in Zambia. This study investigated the prevalence, phenotypic and genotypic characteristics of S. aureus from pigs and workers at farms and abattoirs handling pigs in Lusaka Province of Zambia. A total of 492 nasal pig swabs, 53 hand and 53 nasal human swabs were collected from farms and abattoirs in selected districts. Standard microbiological methods were used to isolate and determine antimicrobial susceptibility patterns of S. aureus. Polymerase Chain Reaction was used to confirm the species identity and detect antimicrobial resistance and virulence genes of isolates, whereas genetic diversity was evaluated using spa typing. Overall prevalence of S. aureus was 33.1%, 37.8% for pigs and 11.8% for humans. The isolates were resistant to several antibiotics with resistance ranging from 18% to 98% but were all susceptible to vancomycin. Typical LA-SA spa types were detected. The presence of plasmid mediated resistance genes such as tetM (12.8%), other resistance determinants and immune evasion cluster genes among the isolates is of great public health concern. Thus, continuous surveillance of S. aureus using a “One health” approach is warranted to monitor S. aureus infections and spread of antimicrobial resistance.

Antimicrobial resistance, virulence factors, and genotypes of Pseudomonas aeruginosa clinical isolates from Gorgan, northern Iran.

Pseudomonas aeruginosa is an important nosocomial pathogen with a capacity of resistance to multiple antibiotics and production of various extracellular and cell-associated virulence factors that clearly contribute to its pathogenicity. The objective of this study was to investigate the antibiotic susceptibility, virulence factors, and clonal relationship among clinical isolates of P. aeruginosa. Different clinical specimens from hospitalized patients were investigated for P. aeruginosa. Susceptibility of the isolates was evaluated by disc diffusion and broth microdilution methods, as described by the Clinical and Laboratory Standards Institute (CLSI) guideline. A total of 97 P. aeruginosa isolates were recovered from clinical specimens. The percentage of isolates resistant to antimicrobials was imipenem 25.77%, meropenem 15.46%, gentamicin 16.49%, tobramycin 15.46%, amikacin 16.49%, ciprofloxacin 20.61%, levofloxacin 24.74, ceftazidime 20.61%, piperacillin 15.46%, piperacillin/tazobactam 12.37%, colistin 9.27%, and polymyxin B 11.34%. Of isolates, 87.62% possessed β-hemolytic activity, 78.35% lecithinase, 59.8% elastase, 37.11% DNase, and 28.86% twitching motility. The frequency of virulence genes in isolates was lasB 82.47%, plcH 82.47%, exoA 58.76%, exoS 56.7%, and pilA 10.3%. ERIC-PCR typing clustered P. aeruginosa isolates to 19 common types (CT1-CT19) containing isolates from different hospitals and 43 single types (ST1-ST43). Colistin and polymyxin B were the most effective agents against the majority of P. aeruginosa isolates, emphasizing the effort to maintain their antibacterial activity as last-line therapy. The frequency of some virulence factors and genes was noticeably high, which is alarming. In addition, more effective strategies and surveillance are necessary to confine and prevent the inter-hospital and/or intra-hospital dissemination of P. aeruginosa between therapeutic centers.

Detection and distribution of virulence genes in Aeromonas hydrophila isolates causing infection in cultured carps.

Aeromonas hydrophila is a bacterium associated with many diseases and disorders such as fin rot, skin ulcers and lethal hemorrhagic septicemia in fish. It bears several virulence factors including type III secretion system (T3SS), aerolysin, cytolytic enterotoxin and enzymes (e.g., hemolysins, lipase) that seem to play an important role in its pathogenesis. Detection of virulence markers by polymerase chain reaction (PCR) is a key procedure in defining the patho-genic ability of pathogenic bacteria and preparing a vaccine for its treatment. In this sense, this study was aimed to determine the frequency of virulence genes in isolates obtained from infected cultured carps in Khuzestan province. Out of 200 moribund carps with septicemic symptoms, 125 isolates were belonged to the motile aeromonads and 59 isolates were identified as A. hydrophila by biochemical methods. Finally, using PCR analysis, 31 isolates were identified as A. hydrophila. Five virulence genes were detected in these isolates including hemolysin, aerolysin, cytolytic enterotoxin and T3SS (aopB and ascV) by specific primers. Results showed that 23 (74.19%), 18 (58.06%), 16 (51.61%), 13 (41.63%) and 10 (32.25%) isolates possessed cytolytic enterotoxin, hemolysin, aerolysin, and T3SS genes, respectively. The results of the present study showed that among 31 isolates, only five isolates had all of dominant virulence genes. Thirteen other isolates had genotypes including hlyA+, aerA+, and act+. The remaining isolates had at least one virulence gene. This study showed that determination of the virulence genes by PCR can be a reliable method to identify a potential pathogenic Aeromonad strain.

Proteolytic activities and safety use of Enterococcus faecalis strains isolated from Turkish White Pickled Cheese and milk samples

In this study, Enterococcus faecalis proteolytic strains which have the potential to degradation of bovine milk proteins were isolated from Turkish White Pickled Cheeses and milk samples. E. faecalis strains were found to have strong caseinolytic activity. The extracellular protease enzymes produced by E. faecalis strains from 60 different samples were analyzed in the pattern of bands on a stained SDS-PAGE gel. The highest proteolytic activity of E. faecalis isolates were determined at pH 7.0 and 40 ℃ for 24 h. In addition, antimicrobial resistance and the presence of selected virulence genes of isolates were investigated for microbiological safety. These findings further emphasize that the E. faecalis isolates can be effective in the degradation of bovine milk proteins.

Detection of SHIGA-TOXIN producing E. coli in some retail markets in Egypt using qPCR assay with special reference to serotyping

Background: Shiga toxin-producing Escherichia coli are dangerous foodborne pathogens that represent a severe public health issue worldwide. Raw foods are considered an important source of STEC infection in humans. Objective: In the current study, STEC contamination was investigated in 80 raw foods (chicken, beef, and milk) and water collected from different localities of Greater Cairo using Real-Time PCR. Moreover, the virulence genes of isolates were characterized. Results: STEC was detected in eight samples, (7 beef and 1 chicken), which represent about 10% of the tested samples. Positive beef and chicken samples show the presence of 13 and 2 STEC genes, respectively. Five samples were positive for eaeA (intemin), two samples were positive for stx1 gene and eight samples were positive for stx2 gene. Beef samples reveal the highest incidence of virulence gene stx2 (35%), followed by eaeA (20%), then stx1 (10%). The incidence of STEC was lower in chicken samples and the prevalence of virulence gene was 5% for stx2 and eaeA, respectively. Stx2 gene was the most prevalent subtype identified in beef samples. Serotyping of isolated STEC strains (14) revealed isolation of seven STEC strains belong to O157 serogroup, two strains belong to O111and five strains belong to serogroup O26. Conclusion: The current study concluded that recovery of STEC from raw chicken and beef samples is of important concern.

Phylogenetic groups and virulence genes of Escherichia coli strains isolated from the children gut microbiota.

Escherichia coli is characterized by a wide intraspecific diversity. The species includes both commensals and pathogens that cause diarrhea and extra-intestinal diseases. Pathogenic strains differ from non-pathogenic ones by the presence of virulence factors and their genes. The phylogenetic structure of the species is represented by four main groups (A, B1, B2, D), which differ in their prevalence among residents of different geographical regions. Pathogenic members of the species have been studied in detail, while non-pathogenic strains have not received such attention. This report presents the results of a study of 511 E. coli strains isolated from the gut microbiota of children without diarrhea and urinary tract infections, aged from 1 month to 17 years, living in St. Petersburg. The main phylogenetic groups were determined by PCR, and E. coli virulence genes associated with diarrhea and extra-intestinal diseases were identified. Results: population structure of E. coli is represented by the following groups: A-33.3%, B1-6.7%, B2-34.0%, D-26%. In the studied population 2.5% of strains belonded to EPEC and 4.5% to EAggEC. EPEC virulence genes were more often detected in strains of phylogroup B1, and EAggEC virulence genes in isolates of phylogroup D. The prevalence of extra - intestinal virulence genes was as follows: pap - 29.5%; sfa - 19.8%; afa - 3.3%; hly - 20.9%; cnf - 17.4%; aer-20.0%. The pap, sfa, hly, and cnf genes were detected mostly in the B2 phylogenetic group. Obtained data shows the similarity of E. coli phylogenetic groups structure in St. Petersburg with E. coli populations isolated from residents of Paris and Sydney. Analysis of the virulence genes prevalence showed the dependence of their presence on the genetic background bacteria.

Improved β-Lactam Susceptibility Against ica-Dependent Biofilm-Embedded Staphylococcus aureus by 2-Aminothiazole.

Due to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) producing biofilm, causing recurrent infections worldwide, new therapeutic combinations need to be discovered to prevent resistance and to make treatment available. It was aimed to improve β-lactam susceptibility against ica-dependent biofilm-embedded Staphylococcus aureus (S. aureus), even in blaZ and mecA carriers, by 2-aminothiazole. Virulence genes in isolates were detected by qRT-PCR. MICs, MBCs of 2-aminothiazole and β-lactams against planktonic and sessile ica-dependent biofilm-producer isolates were investigated. Activities of 2-aminothiazole combined β-lactams against sessile one MRSA ATCC 43300, one MRSA, and two MSSA were investigated by checkerboard-assay. Activities of 2-aminothiazole combined β-lactams were found synergistic and partially-synergistic against both biofilm-embedded MRSA and MSSA-isolates with FIC-indexes ranging between 0.193 - 0.387 and 0.535 - 0.745 and between 0.358 - 0.415 and 0.707 - 1.0, respectively. MICs of β-lactams against MSSA and MRSA were decreased 2- to 8-fold and 0- to 8-fold by sub-MICs of 2-aminothiazole, respectively. Sub-MIC 2-aminothiazole combined Sub-MIC β-lactams can be a choice in varying applications to treat biofilm-associated staphylococcal infections.

Long-term methicillin-resistant Staphylococcus aureus bacteremia persisting for more than 2 weeks: risk factors and outcomes.

The clinical significance of long-term methicillin-resistant Staphylococcus aureus (MRSA) bacteremia remains unclear. We evaluated the clinical, microbiological characteristics, and clinical outcomes of long-term MRSA bacteremia. A nested case-control study was conducted in a prospective cohort of adult patients with MRSA bacteremia at a tertiary hospital between August 2008 and December 2017. Patients with long-term MRSA bacteremia (≥ 14days) were compared with control patients, defined as having bacteremia that resolved in less than 3days. The following variables were documented: heteroresistance phenotype, genotypes, agr dysfunction, and the presence of 41 virulence genes in isolates. Of the total 890 patients studied, 69 patients (7.8%) exhibited long-term MRSA bacteremia and 599 (67.3%) exhibited resolving bacteremia. The most common sources of long-term bacteremia were central venous catheter-related infection (39%) and osteomyelitis (19%). Independent risk factors for long-term MRSA bacteremia included male sex (adjusted odds ratio [aOR] = 2.43), community-acquired bacteremia (aOR = 2.93), the presence of a prosthetic device (aOR = 3.40), and osteomyelitis (aOR = 7.98). Metastatic infections developed more frequently in patients with long-term bacteremia than in those with resolving bacteremia (56.5% vs. 8.0%; P < 0.001). Although there were no significant differences in 30-day, 12-week, or in-hospital mortality rates between the two groups, infection-attributable mortality was higher in the long-term bacteremia group (23.2% vs. 11.5%; P = 0.01). Microbiological characteristics did not differ significantly between the two groups. Clinical factors, including community-acquired bacteremia, the presence of a prosthetic device, and osteomyelitis, appear to contribute to long-term MRSA bacteremia more than microbiological factors.

Arcobacter spp. in raw milk from vending machines in Piedmont and occurrence of virulence genes in isolates.

Arcobacter spp. has been recognized as an emerging foodborne pathogen and a hazard to human health. In the dairy chain, it has been isolated from different sources, nevertheless data on Arcobacter occurrence in raw milk provided by vending machines are few. This study aimed to identify potentially pathogenic Arcobacter spp. in raw milk intended for human consumption sold through vending machines located in Piedmont. In an 8-month period, 37 raw milk samples were collected from 24 dairy farms: 12 (32,4%) were collected directly in farm from bulk tank milk and 25 (67,6%) from vending machines. Eight (21,6%) out of the 37 milk samples and 7 (29,2%) out of the 24 dairy farms were positive for Arcobacter spp. by culture examination. Four (16%) out of the 25 samples from vending machines and 4 (33,3%) out of the 12 samples from bulk tank milk were positive. All 8 isolates were identified as A. butzleri both by MALDI-TOF MS and multiplex end-point PCR. According to the detection of virulence genes, a total of four Patho-types were highlighted: 5 isolates in P-type 1 and only one isolate for each of the P-types 2-3-4. A. butzleri isolates carrying encoding virulence factors genes were isolated from raw milk intended for human consumption: these findings strengthen the compulsory consumption after boiling as required by current legislation and suggest the need of enlarging the analytical investigations to other microorganisms not yet included in the food safety criteria.

Characterization of Salmonella spp. Isolated From Poultry Giblets, Calves and Human Beings in Menoufiya Governorate

Salmonellosis remains as an important public health problem and of economic importance worldwide. The aim of this study was to indicate the epidemiology of salmonellosis in both animal and human being in Menofiya Governorate. A total of 352 samples from poultry giblets (52 liver, 32 gizzard, 30 heart), frozen minced meat (58), calves faeces (50) and 130 stool samples were collected and examined bacteriologically, biochemically. Our results revealed that the prevalence of Salmonella spp. was 71.15% (37/52), 59.4% (19/32), 60% (18/30), 24.14% (14/58), 6% (3/50) and 42.3% (55/130) in liver, gizzard, heart, frozen minced meat, calves fecal matter and human stool, respectively. Moreover, 10 isolates of them had been serotyped and for further confirmation 33 isolates from these sources were examined using PCR to detect presence of Salmonella species invA gene and virulence genes (mgtC and hilA). By serotyping S.typhimurium was detected in liver, heart, frozen minced meat and calves fecal matter, S.enteritidis was found in gizzard and human stool samples, while S.kentucky was only detected from human stool samples. Furthermore, PCR on 33 isolates detected (100%) for invA, (84.85%) for mgtC and (90.9%) for hilA gene. In conclusion, Salmonella species has potential zoonotic spread and the presence of virulence genes in isolates from animals, products and in-contact human being, confirming the role of food from animal origin in transmission of salmonellosis.

The Prevalence of Virulence Factors in Human and Environmental Isolates of Pseudomonas aeruginosa

Background: Pseudomonas aeruginosa as a gram-negative bacterium can be detected all around us, as it is generally distributed in different environments and can act as a probable cause of human diseases especially in immunocompromised patients. This bacterium also is a leading cause of nosocomial infections in burn intensive care units. The aim of this study was to evaluate the presence of some virulence genes in P. aeruginosa isolated from different sources. Methods: Pseudomonas aeruginosa isolates were evaluated for the presence of virulence factors including toxA, phzM, lasB, exoU, exoS genes by polymerase chain reaction (PCR). Results: According to our findings, the prevalence of toxA, phzM, lasB, exoU, and exoS virulence genes in the isolates originated from human sources was 86%, 16%, 94%, 100%, and 78%, respectively. While, the above-mentioned virulence factors were present in 46%, 4%, 68%, 64%, and 62% of environmental samples, respectively. Conclusions: Findings of this study indicated that the presence of virulence genes in human isolates was greater than their presence in environmental isolates. Hence, it seems this difference may have caused infections in humans.

P. aeruginosa blood stream infection isolates: A “full house” of virulence genes in isolates associated with rapid patient death and patient survival

We have recently characterised the epidemiology of P. aeruginosa blood stream infection (BSI) in a large retrospective multicentre cohort study [1]. Utilising corresponding patient BSI isolates we aimed to characterise the genotypic virulence profile of the P. aeruginosa isolates that were associated with rapid death in the non-neutropenic host. Five P. aeruginosa BSI episodes were identified from a larger cohort of P. aeruginosa BSI episodes previously described by McCarthy et al. [1]. The genotypic profile of another 5 isolates from this cohort in whom the non-neutropenic host had survived one year post the BSI was also analysed for comparison. These isolates underwent Illumina whole genome sequencing, de novo assembly and annotation. A comprehensive suite of virulence genes was collated from the Pseudomonas Genome Database (http://www.pseudomonas.com/) and were searched by BLAST based analysis in assemblies of all BSI isolates [2]. There was extensive conservation of virulence genes across all of the BSI isolates studied. The exoU gene was found in two isolates from patients who died rapidly and in one isolate from a patient that survived one year post BSI. The higA and higB genes were detected in all isolates. The exlA gene was not detected in any of the isolates studied. These findings suggest that to cause a BSI that it is only the virulent P. aeruginosa isolate that succeeds. The virulence gene profile seen was independent of patient outcome. Further phenotypic correlation is required to determine if there is any difference in genotypic expression by the BSI isolates that were associated with rapid death of the host and those BSI isolates associated with host survival at one year.

Virulence genes in isolates of Klebsiella pneumoniae from the UK during 2016, including among carbapenemase gene-positive hypervirulent K1-ST23 and 'non-hypervirulent' types ST147, ST15 and ST383.

Klebsiella pneumoniae is a concern because of its multidrug resistance and the ability of hypervirulent types, especially capsular type K1-clonal complex 23 (K1-CC23), to cause community-acquired, life-threatening infections. Hypervirulent types carry an array of virulence genes including rmpA/rmpA2, coding for capsule up-regulation. We sought to identify isolates carrying these elements among submissions to the UK national reference laboratory during 2016. Virulence elements and carbapenemase genes were sought by PCR or from whole genome sequences. Isolates were typed by variable number tandem repeat analysis or by multi locus sequence typing from whole genome sequences. Long read nanopore sequencing was carried out on two isolates.Results/Key findings. Twelve of 1090 isolates (1.1 %) belonged to hypervirulent K1-CC23, with one carrying blaOXA-48 (KpvST23L_OXA-48). A further 24 rmpA/rmpA2-positive isolates were detected: eight belonged to hypervirulent types of capsular types K2 and K54; and 14 belonged to 'non-hypervirulent' ST147, ST15 and ST383 and also carried carbapenemase gene(s). Virulence, heavy metal and antibiotic resistance gene contents were compared from whole genome sequences of KpvST23L_OXA-48 and one of the ST147 isolates carrying blaNDM-1. They carried 94/96 and 26/96 of the virulence genes sought, and 23/23 and 9/23 of the heavy metal resistance genes, respectively. In the ST147 isolate, rmpA/rmpA2 and the aerobactin siderophore cluster were on a large virulence plasmid together with resistance genes. The yersiniabactin cluster was widely present among carbapenemase gene-positive isolates, including among those that were rmpA/rmpA2-negative. Our results highlight a combination of virulence and resistance genes, which could lead to untreatable invasive infections.