Distribution Of Virulence Genes Research Articles

Phenotypic and Genotypic Antibiotic Resistance Patterns of Clinical Shigella Isolates from Tehran, Iran

Background: The emergence of multidrug-resistant (MDR) Shigella is a health concern in both developed and developing countries. The indiscriminate use of antibiotics without considering resistance patterns has led to the emergence of resistant strains. Objectives: This study aimed to investigate the phenotypic and genotypic patterns of antibiotic resistance and virulence gene distribution in Shigella isolates from patients in Tehran, Iran. Methods: In this cross-sectional study, 60 Shigella isolates were collected from patients referred to Milad Hospital and Pasargad Laboratory in Tehran. The isolates were gathered over four months, from February 2023 to June 2023. After biochemical and genetic confirmation of the isolates, the disk diffusion method was employed to determine antibiotic resistance patterns. The distribution of beta-lactamase genes (blaCTX-M1, blaCTX-M2, blaCTX-M8, blaSHV, blaTEM, and blaOXA) and virulence genes (ial, virF, invE, sigA, and pic) was investigated in Shigella isolates using the multiplex PCR method. SPSS statistical software version 22 was used for data analysis. Results: Thirty-six percent of isolates were found to be MDR. The highest rate of resistance was against tetracycline (90%) and ampicillin (80%). The lowest resistance rate was against azithromycin (1.9%) and amikacin (7.1%). The blaCTX-M1 and blaCTX-M8 genes were more prevalent, detected in 38.3% and 50% of the isolates, respectively. However, the blaSHV and blaCTX-M2 genes were not detected in any of the isolates. Additionally, 32% of the MDR isolates harbored both the blaCTX-M1 and blaCTX-M8 genes simultaneously. The distribution of virulence genes ial, virF, invE, sigA, and pic in the studied isolates was 28.3%, 85%, 68.3%, 81.7%, and 15%, respectively. Conclusions: The present study emphasizes the increasing trend of MDR Shigella isolates. Therefore, serious measures are needed to prevent the spread of resistant genes. Furthermore, the detection of virulence factors could help in controlling shigellosis, which is a significant global health issue.

Genomic characterization of Listeria monocytogenes recovered from dairy facilities in British Columbia, Canada from 2007 to 2017.

Listeria monocytogenes is a foodborne pathogen of concern in dairy processing facilities, with the potential to cause human illness and trigger regulatory actions if found in the product. Monitoring for Listeria spp. through environmental sampling is recommended to prevent establishment of these microorganisms in dairy processing environments, thereby reducing the risk of product contamination. To inform on L. monocytogenes diversity and transmission, we analyzed genome sequences of L. monocytogenes strains (n = 88) obtained through the British Columbia Dairy Inspection Program. Strains were recovered from five different dairy processing facilities over a 10 year period (2007-2017). Analysis of whole genome sequences (WGS) grouped the isolates into nine sequence types and 11 cgMLST types (CT). The majority of isolates (93%) belonged to lineage II. Within each CT, single nucleotide polymorphism (SNP) differences ranged from 0 to 237 between isolates. A highly similar (0-16 SNPs) cluster of over 60 isolates, collected over 9 years within one facility (#71), was identified suggesting a possible persistent population. Analyses of genome content revealed a low frequency of genes associated with stress tolerance, with the exception of widely disseminated cadmium resistance genes cadA1 and cadA2. The distribution of virulence genes and mutations within internalin genes varied across the isolates and facilities. Further studies are needed to elucidate their phenotypic effect on pathogenicity and stress response. These findings demonstrate the diversity of L. monocytogenes isolates across dairy facilities in the same region. Findings also showed the utility of using WGS to discern potential persistence events within a single facility over time.

Molecular Characteristics and Virulence Profile of Clinical Listeria monocytogenes Isolates in Northern Taiwan, 2009-2019.

Listeria monocytogenes is a critical foodborne pathogen that causes severe invasive and noninvasive diseases and is associated with high mortality. Information on the prevalence of L. monocytogenes infections in Taiwan is very limited. This study aimed to analyze the molecular epidemiological surveillance and virulence gene distribution of 176 human clinical L. monocytogenes isolates collected between 2009 and 2019 in northern Taiwan. Our results showed that the isolates belonged to 4 serogroups (IIa, IIb, IVb, and IIc), with most isolates in serogroups IIa (81/176, 46%) and IIb (71/176, 40.3%). Multilocus sequence typing analysis revealed 18 sequence types (STs) and 13 clonal complexes (CCs). Eighty-four percent of all isolates belonged to six STs: CC87-ST87 (40/176, 22.7%), CC19-ST378 (36/176, 19.9%), CC155-ST155 (28/176, 15.5%), CC1-ST710 (16/176, 8.8%), CC5-ST5 (16/176, 8.8%), and CC101-ST101 (11/176, 6.1%). Furthermore, our analysis showed the distributions of four Listeria pathogenicity islands (LIPI) among all isolates. LIPI-1 and LIPI-2 existed in all isolates, whereas LIPI-3 and LIPI-4 only existed in specific STs and CCs. LIPI-3 existed in the STs, CC1-ST710, CC3-ST3, CC288-ST295, and CC191-ST1458, whereas LIPI-4 could be found in the STs, CC87-ST87 and CC87-ST1459. Strains containing LIPI-3 and LIPI-4 are potentially hypervirulent; thus, 68/176 isolates (39.1%) collected in this study were potentially hypervirulent. Since L. monocytogenes infections are considered highly correlated with diet, molecular epidemiological surveillance of Listeria in food is important; continued surveillance will provide critical information to prevent foodborne diseases.

Differences in molecular characteristics and expression of virulence genes in carbapenem-resistant and sensitive Klebsiella pneumoniae isolates in Ningbo, China.

In recent years, Klebsiella pneumoniae has attracted attention because of its increasing drug resistance. At the same time, the migration and pathogenicity caused by its virulence genes also bring many difficulties to the diagnosis and treatment of clinical infections. However, it is currently unclear whether there are differences in virulence and pathogenicity with changes in drug resistance. To understand the differences in molecular characteristics and expression of virulence genes in carbapenem-resistant Klebsiella pneumoniae (CRKP) and carbapenem-sensitive Klebsiella pneumoniae (CSKP). Using polymerase chain reaction (PCR), we examined capsule polysaccharide-related genes and virulence genes in 150 clinical isolates of CRKP and 213 isolates of CSKP from the local area in Ningbo, China. Multilocus sequence typing (MLST) was used to analyze the phylogenetic relationships of clinical Klebsiella pneumoniae isolates. Furthermore, real-time quantitative PCR (RT-qPCR) was used to analyze the expression differences of common virulence genes in CSKP and CRKP, and the virulence was further verified by the larval model of Galleria mellonella. The study found that the detection rates of genes rmpA, iroB, peg-344, magA, aerobactin, alls, kfu, and entB were significantly higher in CSKP compared to CRKP. The capsule gene types K1 and K2 were more common in CSKP, while K5 was more common in CRKP. Hypervirulent Klebsiella pneumoniae (hvKP) was predominantly from CSKP. CRKP strains exhibited noticeable homogeneity, with ST11 being the predominant sequence type among the strains. CSKP strains showed greater diversity in ST types, but ST23 was still the predominant sequence type. Carbapenem-sensitive hypervirulent Klebsiella pneumoniae (CS-hvKP) had higher expression of rmpA and rmpA2 genes compared to carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP). In the wax moth virulence model, the survival rate of CS-hvKP was significantly lower than that of CR-hvKP. There is a significant difference in the distribution of virulence genes between CSKP and CRKP, with CSKP carrying a significantly greater number of virulence genes. Furthermore, compared to CSKP, CRKP strains exhibit noticeable homogeneity, with ST11 being the predominant sequence type among the strains. Additionally, in terms of virulence gene expression efficiency and virulence, CSKP is significantly higher than CRKP.

A longitudinal epidemiology study of fluoroquinolone-nonsusceptible Klebsiella pneumoniae reveals an increasing prevalence of qnrB and qnrS in Taiwan

BackgroundOur objective was to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR) genes in fluoroquinolone-nonsusceptible Klebsiella pneumoniae (FQNSKP) in Taiwan, 1999–2022. MethodsA total of 938 FQNSKP isolates were identified from 1966 isolates. The presence of PMQR and virulence genes, antimicrobial susceptibility, capsular types, and PMQR-plasmid transferability were determined. ResultsAn increasing number of PMQR-containing FQNSKP isolates were observed over the study period. Our results showed that 69.0% (647 isolates) of FQNSKP isolates contained at least one PMQR gene, and 40.6%, 37.0%, and 33.9% of FQNSKP carried aac(6′)-Ib-cr, qnrB, and qnrS, respectively. None of FQNSKP carried qepA and qnrC. The most common combination of PMQR genes was aac(6′)-Ib-cr and qnrB (12.3%). The presence of PMQR genes is strongly related to resistance to aminoglycoside, cephalosporin, tetracycline, and sulfamethoxazole/trimethoprim in FQNSKP. The capsular serotype K64 is the most common serotype we tested in both the non-PMQR and PMQR FQNSKP isolates, while K20 showed a higher prevalence in PMQR isolates. The magA and peg-344 genes showed a significantly higher prevalence rate in non-PMQR isolates than in PMQR isolates. Eleven isolates that carried the PMQR and carbapenemase genes were identified; however, three successful transconjugants showed that the PMQR and carbapenemase genes were not located on the same plasmid. ConclusionsOur results indicated an increasing prevalence of PMQR genes, especially qnrB and qnrS, in FQNSKP in Taiwan. Moreover, the distribution of PMQR genes was associated with capsular serotypes and antimicrobial resistance gene and virulence gene distribution in FQNSKP.

Padrão de resistência a antibióticos e características patológicas de Escherichia coli patogênica aviária O78:K80 em galinhas

Avian pathogenic Escherichia coli (APEC) induces colibacillosis, an acute and systemic disease, resulting in substantial economic losses in the poultry sector. This study aimed to investigate the antibiotic resistance pattern associated with frequent virulence gene distribution in APEC O78:K80 that may cause pathological alterations in chickens. The antibiogram profile showed high resistance to erythromycin, chloramphenicol, tetracycline, ampicillin, and co-trimoxazole, followed by intermediate resistance to ciprofloxacin, levofloxacin, enrofloxacin, norfloxacin, nitrofurantoin, and doxycycline hydrochloride, and sensitive to amikacin, streptomycin, gentamicin, and colistin. Virulence gene distribution identifies eight (irp-2, iutA, ompT, iss, iucD, astA, hlyF, iroN) genes through a conventional polymerase chain reaction. APEC O78:K80 caused significantly high liver enzyme concentrations, serum interleukin-6 and tumor necrosis factor-alpha levels in experimental birds. Also, infected birds have hypoproteinemia, hypoalbuminemia, and hyperglobulinemia. Necropsy examination revealed fibrinous perihepatitis and pericarditis, congested lungs, intestinal ecchymotic hemorrhages and necrotizing granulomatosis of the spleen. Histopathological examination depicted hepatocellular degeneration, myocardial necrosis, interstitial nephritis, intestinal hemorrhages and lymphopenia in the spleen. This study is the first evidence to assess the antibiotic resistance profile linked with virulence genes and clinicopathological potential of APEC O78:K80 in chickens in Pakistan, which could be a useful and rapid approach to prevent and control the disease by developing the control strategies.

Population characteristics of pathogenic Escherichia coli in puerperal metritis of dairy cows in Ningxia region of China: a systemic taxa distribution of virulence factors and drug resistance genes.

Escherichia coli (E. coli) is closely associated with the occurrence of puerperal metritis in dairy cows. E. coli carries some the virulence and multi-drug resistant genes, which pose a serious threat to the health of postpartum cows. In this study, E. coli was isolated and identified from the uterine contents of postpartum cows with puerperal metritis in the Ningxia region of China, and its phylogenetic subgroups were determined. Meanwhile, virulence and drug resistance genes carried by E. coli and drug sensitivity were detected, and the characteristics of virulence and drug resistance genes distribution in E. coli phylogroups were further analyzed. The results showed that the isolation rate of E. coli in puerperal metritis samples was 95.2%. E. coli was mainly divided into phylogroups B2 and D, followed by groups A and B1, and was more connected to O157:H7, O169:H4, and ECC-1470 type strains. The virulence genes were mainly dominated by ompF (100%), traT (100%), fimH (97%), papC (96%), csgA (95%), Ang43 (93.9%), and ompC (93%), and the resistance genes were dominated by TEM (99%), tetA (71.7%), aac(3)II (66.7%), and cmlA (53.5%). Additionally, it was observed that the virulence and resistance gene phenotypes could be divided into two subgroups, with subgroup B2 and D having the highest distributions. Drug sensitivity tests also revealed that the E. coli was most sensitive to the fluoroquinolones enrofloxacin, followed by macrolides, aminoglycosides, tetracyclines, β-lactams, peptides and sulfonamides, and least sensitive to lincosamides. These results imply that pathogenic E. coli, which induces puerperal metritis of dairy cows in the Ningxia region of China, primarily belongs to the group B2 and D, contains multiple virulence and drug resistance genes, Moreover, E. coli has evolved resistance to several drugs including penicillin, lincomycin, cotrimoxazole, and streptomycin. It will offer specific guidelines reference for the prevention and treatment of puerperal metritis in dairy cows with E. coli infections in the Ningxia region of China.

Prevalence, Virulence, and Antimicrobial Resistance of Major Mastitis Pathogens Isolated from Taiwanese Dairy Farms.

Mastitis, a highly prevalent disease in dairy cows, is responsible for massive financial losses due to decreased milk yield, milk quality, and costly medication. This research paper investigates antimicrobial susceptibility in cows and the role played by both resistance and virulence gene distribution in bovine mastitis. A total of 984 raw milk samples were collected from five different dairy farms and cultured on sheep blood agar plates. Antimicrobial susceptibility was determined by disc diffusion, and corresponding resistance and virulence genes were detected by PCR. Among the collected milk samples, 73, 32, and 19 isolates of Streptococcus spp., Staphylococcus spp., and coliforms were identified, respectively. The antimicrobial susceptibility results showed that Streptococcus spp. were resistant to tetracycline (86.30%), neomycin (79.45%), and oxacillin (73.97%). Staphylococcus spp. were resistant to tetracycline (59.37%) and oxacillin (53.12%). Lastly, coliforms were resistant to oxacillin (100%) and bacitracin (68.42%). The genotyping results showed that Streptococcus spp. carried the resistance genes tetM (46.57%) against tetracycline, bcrB (41.09%) against bacitracin, and aph(3)-II (39.72%) against neomycin. Staphylococcus spp. carried the resistance genes bcrB (40.62%) and tetM (18.75%), and coliforms carried the resistance genes tetM (42.10%) and bcrB (57.89%). Moreover, 57.53%, 75.0%, and 63.15% of Streptococcus spp., Staphylococcus spp., and coliforms carried lmb, fib, and ompC virulence genes, respectively. All three tested bacterial genera showed no significant association between antimicrobial resistance genes and virulence factors, although they were negatively correlated (p > 0.05). The combination of resistance gene identification and susceptibility tests as components of the diagnosis of bovine mastitis can help in selecting effective antimicrobial agents to treat it.

Characterization of Staphylococcus aureus Nasal Carriage Among Healthcare Providers in an Intensive Care Unit: Insights into Antibiotic Resistance Profiles and Virulence Gene Distribution

Background: Staphylococcus aureus ranks among the leading causes of serious nosocomial infections. One critical route for the spread of this bacterium within hospitals is via asymptomatic carriers, particularly healthcare providers. Staphylococcus aureus can exist as part of the normal skin flora and within the anterior nostrils of individuals, making healthcare providers a significant vector for transmission. Several genes associated with virulence, such as toxic shock syndrome toxin-1 (tsst-1), alpha-toxin (hla), and panton-valentine leucocidin (pvl), play pivotal roles in the pathogenicity and severity of infections caused by S. aureus. Objectives: This study aimed to characterize S. aureus nasal carriage among healthcare providers in an intensive care unit (ICU), with a particular focus on antibiotic resistance profiles and the prevalence of virulence genes. Methods: Nasal swabs were collected from 120 healthcare workers in the ICU of Ganjavian hospital, Dezful, Iran. Standard microbiological procedures were employed for S. aureus detection. Antibiotic susceptibility testing was conducted using both disk diffusion and minimum inhibitory concentration methods. Polymerase chain reaction (PCR) was employed to identify the presence of the mecA gene and the virulence genes hla, tsst-1, and pvl. A statistical analysis was performed to evaluate the data. Results: The study revealed that 12.5% of healthcare providers were carriers of S. aureus, with 26.6% of them harboring methicillin-resistant S. aureus (MRSA) strains. Antibiotic resistance patterns varied, with a notable resistance to erythromycin and penicillin. The hla gene was detected in 66.6% of S. aureus strains; nevertheless, the tsst-1 and pvl genes were not identified. The study suggests a potential association between high expression of the hla and mecA genes and antibiotic resistance. Conclusions: This study underscores the prevalence of S. aureus nasal carriage, antibiotic resistance patterns, and the distribution of virulence genes among healthcare providers in an ICU setting. The findings emphasize the significance of continuous surveillance and infection control strategies to mitigate the transmission of S. aureus and associated infections within healthcare facilities. The study recommends routine screening of ICU healthcare providers for asymptomatic S. aureus carriers and appropriate interventions to eliminate colonization.

Whole genome sequencing of Vibrio harveyi from different sites in the Mediterranean Sea providing data on virulence and antimicrobial resistance genes

Vibriosis caused by Vibrio harveyi is an important bacterial infection in the Mediterranean farming of European seabass and gilthead sea bream. Genomic information about V. harveyi contributes to understanding its pathogenesis and virulence. Sixteen V. harveyi strains obtained from diseased seabass and sea bream from Croatia, France, Italy, Spain, Tunisia, and Turkey were sequenced using ONT MinION and Illumina HiSeq. The strains were sequenced, de novo assembled, and the genomes analysed for the presence of plasmids, virulence, and antibiotic resistance genes. Antibiotic resistance genes were compared with in vitro susceptibility testing using disc diffusion and microdilution methods. All studied strains had two circular chromosomes, and twelve strains had one to five circular plasmids. A total of 171 virulence genes were determined using the Virulence Factors of Bacterial Pathogens database (VFBD), 150 virulence genes were present on average in each genome and the distribution of virulence genes was similar across strains. Most of the reported virulence genes have been previously described in bacteria of the genus Vibrio, while genes sitA (4/16), sitB (3/16), sitC (4/16), and sitD (3/16) important for iron transport, and the ast gene (10/16) that encodes a heat-stable cytotoxic enterotoxin, were unique in our studied strains. Using the Comprehensive Antibiotic Resistance database (CARD), it was noted that all strains carried the CRP gene encoding resistance to macrolides, fluoroquinolone, and penams, but showed sensitivity to enrofloxacin and florfenicol using in vitro tests. The adeF gene coding for resistance to fluoroquinolones and tetracyclines was detected in lower percentage in thirteen strains was supported with detected sensitivity to florfenicol and oxytetracycline using in vitro tests. The E.coli parE gene was detected in eleven strains that showed sensitivity to florfenicol and oxytetracycline. The gene APH(3”)Ib responsible for resistance to aminoglycosides was present in one strain, though all strains showed susceptibility to gentamicin by in vitro testing. The Tet(D) gene coding for resistance to tetracyclines was found in a single strain showing reduced sensitivity to oxytetracycline. All tested strains were resistant to ampicillin by in vitro testing in line with previously described innate resistance. Phylogenetic analysis based on whole genome sequences showed a clear separation and clustering of the tested strains from the Mediterranean region. The new genomic data and knowledge provided in this study increase the understanding of the pathogenicity and antimicrobial resistance patterns of V. harveyi strains in the Mediterranean region, enabling a common regional approach to prevention and mitigation of the disease.

Characterization of the Virulency of Vibrio spp. in Giant Tiger Shrimp (Penaeus monodon) from Peninsular Malaysia

Nowadays, bacterial diseases caused by Vibrio spp. pose a significant obstacle to aquaculture growth, affecting socioeconomic development. The presence of pathogenic Vibrio spp. are gaining attention due to widespread mortality in fish and shellfish worldwide. This study investigates the distribution of virulence genes and their pathogenicity by experimentally infecting a healthy group of cultured shrimp, specifically Penaeus monodon. A total of 225 Vibrio spp. isolated from 210 cultured shrimp from various geographical regions in Peninsular Malaysia were examined, resulting in 13 Vibrio spp. being identified and characterized. According to virulence gene assessment, only eight of the 11 virulence genes were detected in the isolates, including chiA (89%), flaC (74%), tlh (72%), toxR (70%), luxR (40%), pirA (11%), pirB (11%), and hlyA (0.4%). Other virulence genes, such as tdh, trh, and ctxA, were not found in any of the isolates (0%). Then, three Vibrio isolates, including V. parahaemolyticus S12-3, V. campbellii S10-4, and V. rotiferianus S24-4, were selected for pathogenicity test based on highest number of virulence genes in each species. These species were subjected to immersion challenge test against postlarvae (PL) P. monodon approximately PL-20 with three different concentrations of 1 × 106, 1 × 107, and 1 × 108 CFU/mL. The V. parahaemolyticus S12-3 was determined to have lethal concentration 50 (LC50) 1 × 105 CFU/mL after 168 hr of exposure. The immersion challenge test resulted in a pale hepatopancreas and empty guts in P. monodon. Histopathological examination showed sloughing of epithelial cells in the hepatopancreatic tubule, hemocytic infiltration, massive vacuolation, and loss of hepatopancreatic tubule structure. Overall, the study demonstrated the virulence and pathogenicity of V. parahaemolyticus S12-3 toward P. monodon, which could be associated with its virulence properties. Furthermore, the current findings will be useful in developing microbiological risk assessments for shrimp farming and aquaculture management.

Molecular characteristics of Staphylococcus aureus strains isolated from subclinical mastitis of water buffaloes in Guangdong Province, China.

Intramammary infections (IMI) in animals reared for milk production can result in large economic losses and distress to the animals. Staphylococcus aureus is an important causative agent of IMI in dairy cows, but its prevalence in water buffaloes has not been determined. Therefore, the current study was conducted to investigate the prevalence of subclinical mastitis in water buffaloes and the antimicrobial susceptibility, virulence genes and biofilm formation abilities of Staphylococcus aureus isolates recovered from water buffaloes in Guangdong, China. Staphylococcus aureus strains were isolated from milk samples of water buffaloes with subclinical mastitis, and twofold microdilution, PCR and crystal violet staining methods were used to determine antimicrobial susceptibility, distributions of virulence and antimicrobial resistance genes and biofilm formation ability, respectively. Our results indicated that 29.44% of water buffaloes were diagnosed with subclinical mastitis, and the most prevalent pathogens were Escherichia coli (96.17%), coagulase-negative staphylococci (CoNS) (67.60%) and S. aureus (28.57%). Most S. aureus isolates showed resistance to bacitracin, doxycycline, penicillin, florfenicol, and tetracycline but were susceptible to ciprofloxacin, ceftizoxime, cefoquinoxime, and ofloxacin. Moreover, 63.72% of S. aureus isolates were positive for tetM, and the prevalence of msrB, blaZ, mecA, fexA, and tetK ranged from 21.24 to 6.19%. All S. aureus isolates harbored clfB and icaA genes, and the virulence genes hla (93.8%), hld (91.15%), clfA (90.27%), fnbA (86.73%), and hlb (83.19%), and tsst, icaD, sec, see, fnbB, and sea showed a varied prevalence ranging from 3.5 to 65.49%. All S. aureus isolates possessed the ability to form biofilms, and 30.09% of isolates showed strong biofilm formation abilities, while 19.47% of isolates were weak biofilm producers. Our results indicated that subclinical mastitis is prevalent in water buffaloes in Guangdong, China, and S. aureus is prevalent in samples from water buffaloes with subclinical mastitis. Most S. aureus isolates were susceptible to cephalosporins and fluoroquinolones; thus, ceftizoxime and cefoquinoxime can be used to treat subclinical mastitis in water buffaloes.

Molecular Epidemiology of Carbapenem Resistant Klebsiella Pneumoniae in Northern China: Clinical Characteristics, Antimicrobial Resistance, Virulence and Geographic Distribution.

In this article, we studied in detail 74 Carbapenem Resistant Klebsiella pneumoniae (CRKP) in Shanxi to provide essential insight into development of effective strategies for control of CRKP. From 2018 to 2021, we collected 74 clinical CRKP from 11 hospitals in Shanxi Province. Clinical data were obtained from medical records, and all isolates were subjected to antimicrobial susceptibility testing, multi locus sequence typing, capsular serotypes, resistant gene profiles and virulence gene profiles. The synergistic activity was performed by microdilution checkerboard method. Our study found differences in the clinical characteristics of CRKP between regions in Shanxi. Sequence type (ST) 11 was the dominant ST in Shanxi; however, the ST types in Shanxi had become more diverse over time and the proportion of STs showed a more balanced distribution with a significant decrease in ST11. NDM was the most common carbapenemase in Shanxi. In addition, the STs, carbapenemases, serotypes and virulence gene distribution varied by region in Shanxi. Moreover, tigecycline in combination with carbapenems and aztreonam had an excellent synergistic effect on CRKP in vitro. The results of this study provide essential insight into development of effective strategies for control of CRKP in Shanxi.

Molecular epidemiology and antibiotic resistance of Pseudomonas aeruginosa isolated from blood in a hospital in Shandong Province from 2014 to 2021

Objective: To identify the antibiotic resistance, virulence genes, and sequence types of Pseudomonas aeruginosa (P. aeruginosa) strains isolated from blood. Methods: From November 2014 to December 2021, a total of 94 nonrepetitive P. aeruginosa isolates were obtained from blood samples of patients at the First Affiliated Hospital of Shandong First Medical University in Shandong Province, China. The bacteria were identified using matrix-assisted laser desorption ionization time of flight mass spectrometry. Antibiotic resistance of the P. aeruginosa isolates was detected using Vitek 2 Compact system. Polymerase chain reaction (PCR) was conducted for the 18 virulence genes, and multi locus sequence typing (MLST) was performed to identify the sequence types of the P. aeruginosa strains. The resistance rates and distributions of virulence genes between carbapenem resistant pseudomonas aeruginosa (CRPA) and carbapenem susceptible pseudomonas aeruginosa (CSPA) isolates were compared using the Chi-square test. Results: Among 94 P. aeruginosa isolates, 19 (20.2%) isolates were found to be multidrug resistant (MDR) bacteria, of which 17 were CRPA isolates and 2 were CSPA isolates. All strains contained more than 10 virulence genes. Except for exoU gene, the detection rate of other genes was above 83%. MLST analysis revealed a total of 66 different STs, including 59 existing STs and 7 novel STs. Among them, ST244 (n=11, 11.7%) and ST270 (n=7, 7.4%) were the dominant STs. Although these two types of isolates harbored the same virulence genes, the resistance rates to carbapenem were different. 54.5% (6/11) ST244 isolates were CRPA but all 7 ST270 isolates were CSPA. Conclusion: Although the resistance rates of P. aeruginosa strains isolated from blood were at a low level, some MDR and CRPA isolates were detected. As the high virulence gene detection rates and genetic diversity were found for P. aeruginosa strains isolated from blood, close attention should be paid to avoid transmission and outbreaks.

Characterization of uropathogenic Escherichia coli phylogroups associated with antimicrobial resistance, virulence factor distribution, and virulence-related phenotypes.

In this study, we compared the characteristics of different uropathogenic Escherichia coli phylogroups. A total of 844 E. coli isolated from urine were enrolled and the antimicrobial susceptibility of E. coli to 22 antibiotics was determined by disk diffusion test. The distribution of phylogroups and 20 virulence factor genes was determined by PCR. Phenotypes associated with bacterial virulence, including motility, biofilm formation, and the production of curli and siderophore, were examined. Phylogroup B2 was dominant in our isolates (64.8%), followed by phylogroups D (8.6%), B1 (7.8%), F (6.0%), C (4.5%), A (3.1%), untypable (2.8%), E (1.8%), and clade I (0.5%). The prevalence of multidrug-resistant strains was highest in phylogroup C (86.8%), followed by E (80.0%), F (75.0%), and D (71.2%). Moreover, 23.5% of the phylogroup F E. coli were extensively drug-resistant. Phylogroup B2 E. coli had an average of the highest virulence factor genes (10.1 genes/isolate). Compared to phylogroup B2 E. coli, phylogroups F and clade I E. coli had higher motility while phylogroup C E. coli had lower motility. >60% of phylogroups A and C E. coli showed very low curli production. In contrast, 14%, 10%, and 7%, of E. coli in phylogroups F, B2, and E, produced a very high amount of curli, respectively. Surprisingly, phylogroup A E. coli showed the highest virulence to larvae, followed by phylogroups B2 and C. In summary, we first characterized and revealed that the antimicrobial resistance, virulence gene distribution, motility, and curli production, were associated with in E. coli phylogroups.

Virulence genes identification in Salmonella enterica isolates from humans, crocodiles, and poultry farms from two regions in Colombia.

Salmonella spp. is frequently found in the digestive tract of birds and reptiles and transmitted to humans through food. Salmonellosis is a public health problem because of pathogenicity variability in strains for virulence factors. This study aimed to identify the virulence genes in Salmonella isolates from humans, crocodiles, broiler cloacas, and broiler carcasses from two departments of Colombia. This study was conducted on 31 Salmonella enterica strains from humans with gastroenteritis (seven), crocodiles (seven), broiler cloacas (six), and broiler carcasses (12) from Tolima and Santander departments of Colombia, belonging to 21 serotypes. All samples were tested for Salmonella spp. using culture method on selective and non-selective mediums. Extraction of genomic DNA was performed from fresh colonies, DNA quality was verified by spectrophotometry and confirmed by amplification of InvA gene using conventional polymerase chain reaction (PCR). bapA, fimA, icmF, IroB, marT, mgtC, nlpI, oafA, pagN, siiD, spvC, spvR, spvB, Stn, and vexA genes were amplified by PCR. The most prevalent gene was bapA (100%), followed by marT (96.77%), mgtC (93.55%), and fimA (83.87%). Likewise, IroB (70.97%), Stn (67.74%), spvR (61.29%), pagN (54.84%), icmF (54.8%), and SiiD (45.16%) were positive for more than 50% of the strains. Furthermore, none of the isolates tested positive for the vexA gene. Salmonella isolates presented 26 virulence profiles. This study reported 14 virulence genes in Salmonella spp. isolates from humans with gastroenteritis, crocodiles, and broiler cloacas and carcasses. The distribution of virulence genes differed among sources. This study could help in decision-making by health and sanitary authorities.

Incidence and Virulence Factor Profiling of Vibrio Species: A Study on Hospital and Community Wastewater Effluents.

This study aimed to determine the incidence and virulence factor profiling of Vibrio species from hospital wastewater (HWW) and community wastewater effluents. Wastewater samples from selected sites were collected, processed, and analysed presumptively by the culture dependent methods and molecular techniques. A total of 270 isolates were confirmed as Vibrio genus delineating into V. cholerae (27%), V. parahaemolyticus (9.1%), V. vulnificus (4.1%), and V. fluvialis (3%). The remainder (>50%) may account for other Vibrio species not identified in the study. The four Vibrio species were isolated from secondary hospital wastewater effluent (SHWE), while V. cholerae was the sole specie isolated from Limbede community wastewater effluent (LCWE) and none of the four Vibrio species was recovered from tertiary hospital wastewater effluent (THWE). However, several virulence genes were identified among V. cholerae isolates from SHWE: ToxR (88%), hylA (81%), tcpA (64%), VPI (58%), ctx (44%), and ompU (34%). Virulence genes factors among V. cholerae isolates from LCWE were: ToxR (78%), ctx (67%), tcpA (44%), and hylA (44%). Two different genes (vfh and hupO) were identified in all confirmed V. fluvialis isolates. Among V. vulnificus, vcgA (50%) and vcgB (67%) were detected. In V. parahaemolyticus, tdh (56%) and tlh (100%) were also identified. This finding reveals that the studied aquatic niches pose serious potential health risk with Vibrio species harbouring virulence signatures. The distribution of virulence genes is valuable for ecological site quality, as well as epidemiological marker in the control and management of diseases caused by Vibrio species. Regular monitoring of HWW and communal wastewater effluent would allow relevant establishments to forecast, detect, and mitigate any public health threats in advance.

Genetic characteristics, antimicrobial susceptibility, and virulence genes distribution of Campylobacter isolated from local dual-purpose chickens in central China.

Food-borne antibiotic-resistant Campylobacter poses a serious threat to public health. To understand the prevalence and genetic characteristics of Campylobacter in Chinese local dual-purpose (meat and eggs) chickens, the genomes of 30 Campylobacter isolates, including 13C. jejuni and 17C. coli from Jianghan-chickens in central China, were sequenced and tested for antibiotic susceptibility. The results showed that CC-354 and CC-828 were the dominant clonal complexes of C. jejuni and C. coli, respectively, and a phylogenetic analysis showed that three unclassified multilocus sequence types of C. coli were more closely genetically related to C. jejuni than to other C. coli in this study. Of the six antibiotics tested, the highest resistance rates were to ciprofloxacin and tetracycline (100%), followed by lincomycin (63.3%), erythromycin (30.0%), amikacin (26.7%), and cefotaxime (20.0%). The antibiotic resistance rate of C. coli was higher than that of C. jejuni. The GyrA T86I mutation and 15 acquired resistance genes were detected with whole-genome sequencing (WGS). Among those, the GyrA T86I mutation and tet(O) were most prevalent (both 96.7%), followed by the blaOXA-type gene (90.0%), ant(6)-Ia (26.7%), aac(6')-aph(3'') (23.3%), erm(B) (13.3%), and other genes (3.3%). The ciprofloxacin and tetracycline resistance phenotypes correlated strongly with the GyrA T86I mutation and tet(O)/tet(L), respectively, but for other antibiotics, the correlation between genes and resistance phenotypes were weak, indicating that there may be resistance mechanisms other than the resistance genes detected in this study. Virulence gene analysis showed that several genes related to adhesion, colonization, and invasion (including cadF, porA, ciaB, and jlpA) and cytolethal distending toxin (cdtABC) were only present in C. jejuni. Overall, this study extends our knowledge of the epidemiology and antibiotic resistance of Campylobacter in local Chinese dual-purpose chickens.

Evaluation of Virulence of Salmonella Infantis and Salmonella Enteritidis with In Vitro and In Vivo Models.

Salmonella Infantis and Enteritidis serovars have been reported as important causes of salmonellosis in humans worldwide. However, the virulence of these two serovars has yet to be compared. To evaluate the virulence of Salmonella Infantis (n = 23) and Salmonella Enteritidis (n = 7), we used two models: the Caco2 cells model (in vitro) and the Galleria mellonella model (in vivo). Additionally, the virulence genes of all tested strains were contrasted with phenotypic outcomes. Results showed that adhesion means were 18.2% for Salmonella Enteritidis and 38.2% for Salmonella Infantis strains. Invasion means were 77.1% for Salmonella Enteritidis and 56.2% for Salmonella Infantis strains. Significant differences were found between serovars in adherence and invasion assays. Mortality rates (58% for Salmonella Enteritidis and 62.6% for Salmonella Infantis) were not significantly different between serotypes. The distribution of virulence genes showed that genes fae (fimbrial adherence determinants) and shdA (nonfimbrial adherence determinants) were only found in Salmonella Infantis strains. On the other hand, the rck gene (invasion) and Plasmid-encoded fimbriae genes (pef A, B, C, D) were present in Salmonella Enteritidis exclusively. In conclusion, this study shows that Salmonella Enteritidis has a higher virulence potential under experimental conditions than Salmonella Infantis. However, more studies are needed to determine the risk that Salmonella Infantis could represent compared with Salmonella Enteritidis. Moreover, other in vivo models should be considered to assess the virulence of these serovars.

The frequency of adherence, biofilm-associated, Arginine Catabolic Mobile element genes, and biofilm formation in clinical and healthcare worker coagulase-negative staphylococci isolates

BackgroundHealthcare workers may pave the way for increased infections in hospitalized patients by coagulase-negative staphylococci (CoNS). Biofilm formation and antibiotic resistance are the major problems posed by CoNS in nosocomial infections. In this study, we determined biofilm production level and the distribution of biofilm-associated and virulence genes, including icaADBC, aap, bhp, atlE, embp, and fbe, as well as IS256, IS257, mecA, and ACME clusters (arc-A, opp-3AB) among 114 clinical (n = 57) and healthcare workers (n = 57) CoNS isolates in Kerman, Iran.ResultsIn this study, more than 80% (n = 96) of isolates were methicillin-resistant CoNS (MR-CoNS). Out of 114 isolates, 33% (n = 38) were strong biofilm producers. Strong biofilm formation was found to be significantly different between clinical and healthcare workers’ isolates (P < 0.050). In addition, 28% (n = 32) of isolates were positive for icaADBC simultaneously, and all were strong biofilm producers. The prevalence of icaADBC, mecA, bhp, fbe, and IS256 in clinical isolates was higher than that in healthcare workers’ isolates (P < 0.050). A significant relationship was observed between clinical isolates and the presence of icaADBC, mecA, bhp, and IS256. Although these elements were detected in healthcare workers’ isolates, they were more frequent in clinical isolates compared to those of healthcare workers.ConclusionsThe high prevalence of ACME clusters in healthcare workers’ isolates and biofilm formation of these isolates partially confirms the bacterial colonization in the skin of healthcare workers. Isolating MR-CoNS from healthcare workers’ skin through similar genetic elements to clinical isolates, such as icaADBC, mecA, and IS256, calls for appropriate strategies to control and prevent hospital infections.