Molecular detection of HpmA and HlyA hemolysin of uropathogenic Proteus mirabilis

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

BACKGROUND

Proteus mirabilis is a significant nosocomial pathogen that is frequently associated with a wide range of infections, 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.

METHODS

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.

RESULTS

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.

CONCLUSION

Sub-MICs of CIP exhibited inhibition of virulence and alterations in morphological integrity against P. mirabilis isolates.

Emergence and genomic chion of Proteus mirabilis harboring blaNDM-1 in Korean companion dogs

Proteus mirabilis is a commensal bacterium dwelling in the gastrointestinal (GI) tract of humans and animals. Although New Delhi metallo-β-lactamase 1 (NDM-1) producing P. mirabilis is emerging as a threat, its epidemiology in our society remains largely unknown. LHPm1, the first P. mirabilis isolate harboring NDM-1, was detected from a companion dog that resides with a human owner. The whole-genome study revealed 20 different antimicrobial resistance (AMR) genes against various classes of antimicrobial agents, which corresponded to the MIC results. Genomic regions, including MDR genes, were identified with multiple variations and visualized in a comparative manner. In the whole-genome epidemiological analysis, multiple phylogroups were identified, revealing the genetic relationship of LHPm1 with other P. mirabilis strains carrying various AMR genes. These genetic findings offer comprehensive insights into NDM-1-producing P. mirabilis, underscoring the need for urgent control measures and surveillance programs using a "one health approach".

Overview of Proteus mirabilis pathogenicity and virulence. Insights into the role of metals

Proteus mirabilis is a Gram-negative bacterium with exclusive molecular and biological features. It is a versatile pathogen acclaimed for its distinct urease production, swarming behavior, and rapid multicellular activity. Clinically, P. mirabilis is a frequent pathogen of the human urinary system where it causes urinary tract infections (UTIs) and catheter-associated urinary tract infections (CAUTIs). This review explores the epidemiology, risk factors, clinical manifestations, and treatment of P. mirabilis infections, emphasizing its association with UTIs. The bacterium's genome analysis revealed the presence of resistance genes against commonly used antibiotics, an antibiotic-resistant phenotype that poses a serious clinical challenge. Particularly, the emergence of extended-spectrum β-lactamases (ESBLs) and carbapenemases resistant P. mirabilis strains. On a molecular level, P. mirabilis possesses a wide array of virulence factors including the production of fimbriae, urease, hemolysins, metallophores, and biofilm formation. This review thoroughly tackles a substantial gap in understanding the role of metallophores in shaping the virulence factors of P. mirabilis virulence. Siderophores, iron metal chelating and transporting metallophores, particularly contribute to the complex pathogenic strategies, displaying a potential target for therapeutic intervention.

Antibiotic resistance and virulence profiles of Proteus mirabilis isolated from broiler chickens at abattoir in South Africa

BACKGROUND

Proteus mirabilis has been identified as an important zoonotic pathogen, causing several illnesses such as diarrhoea, keratitis and urinary tract infections.

OBJECTIVE

This study assessed the prevalence of P. mirabilis in broiler chickens, its antibiotic resistance (AR) patterns, ESBL-producing P. mirabilis and the presence of virulence genes.

METHODS

A total of 26 isolates were confirmed as P. mirabilis from 480 pooled broiler chicken faecal samples by polymerase chain reaction (PCR). The disk diffusion method was used to evaluate the antibacterial susceptibility test, while nine virulence genes and 26 AR genes were also screened by PCR.

RESULTS

All 26 P. mirabilis isolates harboured the ireA (siderophore receptors), ptA, and zapA (proteases), ucaA, pmfA, atfA, and mrpA (fimbriae), hlyA and hpmA (haemolysins) virulence genes. The P. mirabilis isolates were resistant to ciprofloxacin (62%) and levofloxacin (54%), while 8 (30.7%) of the isolates were classified as multidrug resistant (MDR). PCR analysis identified the blaCTX-M gene (62%), blaTEM (58%) and blaCTX-M-2 (38%). Further screening for AMR genes identified mcr-1, cat1, cat2, qnrA, qnrD and mecA, 12%, 19%, 12%, 54%, 27% and 8%, respectively for P. mirabilis isolates. The prevalence of the integron integrase intI1 and intI2 genes was 43% and 4%, respectively.

CONCLUSIONS

The rise of ciprofloxacin and levofloxacin resistance, as well as MDR strains, is a public health threat that points to a challenge in the treatment of infections caused by these zoonotic bacteria. Furthermore, because ESBL-producing P. mirabilis has the potential to spread to humans, the presence of blaCTX -M -producing P. mirabilis in broilers should be kept under control. This is the first study undertaken to isolate P. mirabilis from chicken faecal samples and investigate its antibiotic resistance status as well as virulence profiles in South Africa.

P. mirabilis-derived pore-forming haemolysin, HpmA drives intestinal alpha-synuclein aggregation in a mouse model of neurodegeneration

BACKGROUND

Recent studies suggesting the importance of the gut-microbiome in intestinal aggregated alpha synuclein (α-syn) have led to the exploration of the possible role of the gut-brain axis in central nervous system degeneration. Proteus mirabilis (P. mirabilis), a gram-negative facultative anaerobic bacterium, has been linked to brain neurodegeneration in animal studies. We hypothesised that P. mirabilis-derived virulence factors aggregate intestinal α-synuclein and could prompt the pathogenesis of dopaminergic neurodegeneration in the brain.

METHODS

We used vagotomised- and antibiotic-treated male murine models to determine the pathogenesis of P. mirabilis during brain neurodegeneration. The neurodegenerative factor that is driven by P. mirabilis was determined using genetically mutated P. mirabilis. The pathological functions and interactions of the virulence factors were determined in vitro.

FINDINGS

The results showed that P. mirabilis-induced motor dysfunction and neurodegeneration are regulated by intestinal α-syn aggregation in vagotomised- or antibiotic-treated murine models. We deduced that the specific virulence factor, haemolysin A (HpmA), plays a role in the pathogenesis of P. mirabilis. HpmA is involved in α-synuclein oligomerisation and membrane pore formation, resulting in the activation of mTOR-mediated autophagy signalling in intestinal neuroendocrine cells.

INTERPRETATION

Taken together, the results of the present study suggest that HpmA can interact with α-syn and act as a possible indicator of brain neurodegenerative diseases that are induced by P. mirabilis.

FUNDING

This study was supported by a grant from the National Research Foundation of Korea.

A correlation study between virulence factors and multidrug resistance among clinical isolates of Proteus mirabilis

Treatment of Proteus mirabilis infections is a challenge due to the high abundance of virulence factors and the high intrinsic resistance to antimicrobials. Multidrug resistance (MDR) and extensive drug resistance (XDR) further challenge the control of P. mirabilis infection. This study aimed to investigate the correlation between virulence determinants and multidrug resistance in 100 clinical isolates of P. mirabilis collected in Alexandria from December 2019 to June 2021. Susceptibility to antimicrobials was tested by the Kirby Bauer method. Detection of swarming, urease, protease, hemolysin, and biofilm formation was performed phenotypically and by PCR amplification of zapA, flaA, ureC, mrpA, atfA, ucaA, hpmA, and luxS. MDR and XDR were detected in 34% and 5%, respectively. All isolates were positive for motility, swarming, urease, and protease production. Ninety percent were positive for hemolysin production, while 73% formed biofilm. All isolates possessed the ureC and zapA genes. The luxS, flaA, ucaA, hpmA, mrpA, and atfA genes were detected in 99%, 98%, 96% 90%, 89%, and 84%, respectively. The presence of a single biofilm-related gene was statistically correlated with non-biofilm production (P= 0.018). It was concluded that P. mirabilis isolates from catheterized-urine samples were significantly associated with biofilm formation. MDR and virulence were not statistically correlated. A significant positive correlation was detected between some virulence genes in P. mirabilis. Non-MDR isolates of P. mirabilis had a high abundance of virulence factors with no statistically significant difference from MDR. Most of the MDR and all XDR isolates could produce biofilm.

Genetic analysis of resistance and virulence characteristics of clinical multidrug-resistant Proteus mirabilis isolates

Objective

Proteus mirabilis is the one of most important pathogens of catheter-associated urinary tract infections. The emergence of multidrug-resistant (MDR) P. mirabilis severely limits antibiotic treatments, which poses a public health risk. This study aims to investigate the resistance characteristics and virulence potential for a collection of P. mirabilis clinical isolates.

Methods and results

Antibiotic susceptibility testing revealed fourteen MDR strains, which showed high resistance to most β-lactams and trimethoprim/sulfamethoxazole, and a lesser extent to quinolones. All the MDR strains were sensitive to carbapenems (except imipenem), ceftazidime, and amikacin, and most of them were also sensitive to aminoglycosides. The obtained MDR isolates were sequenced using an Illumina HiSeq. The core genome-based phylogenetic tree reveals the high genetic diversity of these MDR P. mirabilis isolates and highlights the possibility of clonal spread of them across China. Mobile genetic elements SXT/R391 ICEs were commonly (10/14) detected in these MDR P. mirabilis strains, whereas the presence of resistance island PmGRI1 and plasmid was sporadic. All ICEs except for ICEPmiChn31006 carried abundant antimicrobial resistance genes (ARGs) in the HS4 region, including the extended-spectrum β-lactamase (ESBL) gene blaCTX-M-65. ICEPmiChn31006 contained the sole ARG blaCMY-2 and was nearly identical to the global epidemic ICEPmiJpn1. The findings highlight the important roles of ICEs in mediating the spread of ARGs in P. mirabilis strains. Additionally, these MDR P. mirabilis strains have great virulence potential as they exhibited significant virulence-related phenotypes including strong crystalline biofilm, hemolysis, urease production, and robust swarming motility, and harbored abundant virulence genes.

Conclusion

In conclusion, the prevalence of MDR P. mirabilis with high virulence potential poses an urgent threat to public health. Intensive monitoring is needed to reduce the incidence of infections by MDR P. mirabilis.

In Vivo Role of Two-Component Regulatory Systems in Models of Urinary Tract Infections

Two-component signaling systems (TCSs) are finely regulated mechanisms by which bacteria adapt to environmental conditions by modifying the expression of target genes. In bacterial pathogenesis, TCSs play important roles in modulating adhesion to mucosal surfaces, resistance to antibiotics, and metabolic adaptation. In the context of urinary tract infections (UTI), one of the most common types infections causing significant health problems worldwide, uropathogens use TCSs for adaptation, survival, and establishment of pathogenicity. For example, uropathogens can exploit TCSs to survive inside bladder epithelial cells, sense osmolar variations in urine, promote their ascension along the urinary tract or even produce lytic enzymes resulting in exfoliation of the urothelium. Despite the usefulness of studying the function of TCSs in in vitro experimental models, it is of primary necessity to study bacterial gene regulation also in the context of host niches, each displaying its own biological, chemical, and physical features. In light of this, the aim of this review is to provide a concise description of several bacterial TCSs, whose activity has been described in mouse models of UTI.

Drug-Resistant Proteus Virulence Factors Characterization and Their Inhibition Using Probiotic Bacteria

Background: The genus Proteus is a Gram-negative bacterium with a unique characteristic of swarming. Mainly three species are involved in initiating urinary tract infections in the community and in immunocompromised patients, particularly in patients going through long-term catheterization. Due to their strong virulence factors like biofilm formations, protease, and hemolysin, they can lead to lengthening infections in affected individuals. Probiotics are live bacteria and yeasts that are beneficial to human health and can be used as an alternative for the control of nosocomial diseases. Lactobacilli are one of the common probiotics mostly found in yogurt and other fermented foods that have been used as a substitute for infection control. Objectives: The current study was designed to screen potential probiotic bacteria to encounter antibiotic-resistant and virulent Proteus species. Methods: In the current study, using probiotics, already known antibiotic-resistant isolates (n = 25) of Proteus were processed to characterize their virulence factors and their inhibition. Biofilm formation, protease, and hemolysin activities were studied using different phenotypic detection methods. Further, their virulence genes zapA, flg, hmpA, mrp, and rsbA were explored using their genomic DNA. These isolates were found resistant to different classes of antibiotics, and a strategy was designed to inhibit their growth by using probiotic bacteria isolated from the soil. Results: Virulence factors first, all isolates were subjected to biofilm detection, and they were 32% (n = 8) strong, 40% (n = 10) moderate, 16% (n = 4) weak, and 12% (n = 3) non-biofilm producers. All isolates were positive for swarming activity by showing a differentiated ring form of growth. Protease activity showed 56% (n = 14) isolates. Only 24% (n = 6) of isolates were positive for hemolysin. Virulence factors and molecular mechanisms were studied, and gene rsbA responsible for swarming was amplified in 17 (68%) Proteus isolates, and mrp responsible for fimbria was detected in 19 (76%) bacterial isolates. Further, these isolates were subjected to flagella, protease, and hemolysin, and it was revealed that flg 11 (44%), 13 (52%) protease coding zapA, and hmA gene coding hemolysin were amplified in 2 (8%) Proteus isolates. Probiotic bacteria isolated from soil samples were probed for antagonistic activity against Proteus species. The probiotic bacteria were identified as Lactobacillus plantarum, Bacillus subtilis, and B. licheniformis. Due to their strong growth inhibitory effects against Proteus, it is crucial to characterize further the metabolites that have shown suppressive results against Proteus. Conclusions: Findings from the current study will provide new avenues for drug development and also help clinicians manage resistant pathogens in healthcare settings. Probiotic applications for infection control can be useful in treating resistant pathogens. Further purification and characterization of metabolites will provide alternative options for managing resistance issues in microbes.

Augmented Enterocyte Damage During Candida albicans and Proteus mirabilis Coinfection

The human gut acts as the main reservoir of microbes and a relevant source of life-threatening infections, especially in immunocompromised patients. There, the opportunistic fungal pathogen Candida albicans adapts to the host environment and additionally interacts with residing bacteria. We investigated fungal-bacterial interactions by coinfecting enterocytes with the yeast Candida albicans and the Gram-negative bacterium Proteus mirabilis resulting in enhanced host cell damage. This synergistic effect was conserved across different P. mirabilis isolates and occurred also with non-albicans Candida species and C. albicans mutants defective in filamentation or candidalysin production. Using bacterial deletion mutants, we identified the P. mirabilis hemolysin HpmA to be the key effector for host cell destruction. Spatially separated coinfections demonstrated that synergism between Candida and Proteus is induced by contact, but also by soluble factors. Specifically, we identified Candida-mediated glucose consumption and farnesol production as potential triggers for Proteus virulence. In summary, our study demonstrates that coinfection of enterocytes with C. albicans and P. mirabilis can result in increased host cell damage which is mediated by bacterial virulence factors as a result of fungal niche modification via nutrient consumption and production of soluble factors. This supports the notion that certain fungal-bacterial combinations have the potential to result in enhanced virulence in niches such as the gut and might therefore promote translocation and dissemination.

Human and Companion Animal Proteus mirabilis Sharing

Proteus mirabilis is an important pathogen that is associated with urinary tract infections. This study aims to determine the colonization and sharing of P. mirabilis between healthy companion animals and humans that are living together and to evaluate the clonal relatedness of the fecal and clinical stains. Eighteen households (24 humans, 18 dogs, 8 cats) with at least one human–animal pair were studied. Fecal samples were plated onto MacConkey and Hektoen agar and P. mirabilis PFGE analysis (NotI; Dice/UPGMA; 1.5% tolerance) was conducted for the households with multiple positive participants. Antimicrobial-resistance was tested according to CLSI. The fecal P. mirabilis pulse-types were compared with uropathogenic clinical strains (n = 183). Forty-nine P. mirabilis were isolated from eight households. The percentage of colonization in the dogs (44.4%, n = 8/18) was significantly higher (p = 0.0329) than in the humans (12.5%, n = 3/24). Three households had multiple colonized participants. One human–dog pair shared related P. mirabilis strains, which clustered with a clinical strain of animal origin (82.5%). One fecal P. mirabilis strain, from a dog, clustered with two human community-acquired clinical strains (80.9%, 88.9%). To our knowledge, this is the first report of dogs and humans living in close contact and sharing related P. mirabilis strains. The high frequency of colonization in the dogs underlines their possible role as P. mirabilis reservoirs for humans and other dogs.

Proteus mirabilis from community-acquired urinary tract infections (UTI-CA) shares genetic similarity and virulence factors with isolates from chicken, beef and pork meat

Proteus mirabilis is an opportunistic pathogen associated with a variety of infections in humans, especially those in the urinary tract. The isolation of this pathogen in foods of animal origin such as meat is poorly documented and should not be neglected, in view of the zoonotic risk that this can pose to human health. Thus, the objective of this study was to evaluate the prevalence, virulence profile, and similarity between P. mirabilis strains isolated from chicken, beef, and pork meat and those causing community-acquired urinary tract infections (UTI-CA), in order to better understand the role of this bacterium as a zoonotic pathogen. P. mirabilis was isolated from the three types of meat and was found to be more prevalent in chicken. All isolates exhibited several genotypic and phenotypic virulence characteristics, such as adhesion capacity in HEp-2 cell culture, biofilm formation, cytotoxicity in Vero cells and genes that express fimbriae (mrpA, pmfA, ucaA, atfA), hemolysin (hpmA), proteases (zapA and ptA) and siderophore receptor (ireA). UTI-CA strains showed a higher prevalence of ucaA and ireA genes, whereas those from the chicken meat had a higher prevalence of the atfA gene compared with the isolates from the beef and pork meat. It was observed that chicken meat and UTI-CA strains mainly formed very strong biofilms, whereas strains isolated from beef and pork formed more weak and moderate biofilms. Several strains from meat showed close genetic similarity to those from UTI-CA and had the same virulence profiles. Thus, meats may be an important source of the dissemination of P. mirabilis responsible for causing UTIs in the community.

Virulence, resistance and clonality of Proteus mirabilis isolated from patients with community-acquired urinary tract infection (CA-UTI) in Brazil

Urinary tract infections (UTIs) are among the most common human infections, both in hospitals and in communities. Proteus mirabilis is known to cause community-acquired urinary tract infection (CA-UTI) and is an important causative agent of nosocomial UTIs. The pathogenesis of this species is related to its ability to manifest virulence factors, such as biofilms, adhesion molecules, urease, proteases, siderophores, and toxins. In this study, we investigated the virulence, sensitivity to antimicrobials, and clonal relationship of 183 strains isolated from the urine of CA-UTI patients in Londrina, Paraná State, Brazil. A total of 100% of the strains were positive for hpmA, ptA, zapA, mrpA, pmfA, ireA, and atfA virulence genes. The ucaA gene was positive in 81.4% of the cases. The strains showed high rates of sensitivity to the evaluated antimicrobials, and only one was ESBL-positive. All the tested bacteria showed the capacity to form biofilms: 73.2% had a very strong intensity, while 25.7% had a strong intensity, and 1.1% had a moderate intensity. Regarding clonality, 40 clonal clusters were found among the microorganisms tested. Our results showed that strains of P. mirabilis isolated from CA-UTI patients have several virulence factors. Although the urinary clinical isolates studied showed high sensitivity to antimicrobials, the strains showed a strong capacity to form biofilms, making antibiotic therapy difficult. In addition, it was observed that there were clones of P. mirabilis circulating in the city of Londrina.

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All strains presented a variety of virulence genes.

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It was observed that there were clones of P. mirabilis circulating.

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98.1% of strains produced strong or very strong biofilm.

Pathogenic Factors Correlate With Antimicrobial Resistance Among Clinical Proteus mirabilis Strains

Proteus mirabilis is the third most common etiological factor of urinary tract infection. It produces urease, which contributes to the formation of a crystalline biofilm, considered to be one of the most important virulence factors of P. mirabilis strains, along with their ability to swarm on a solid surface. The aim of this study was to analyze the pathogenic properties of two selected groups of clinical P. mirabilis isolates, antimicrobial susceptible and multidrug resistant (MDR), collected from hospitals in different regions in Poland. The strains were examined based on virulence gene profiles, urease and hemolysin production, biofilm formation, and swarming properties. Additionally, the strains were characterized based on the Dienes test and antibiotic susceptibility patterns. It turned out that the MDR strains exhibited kinship more often than the susceptible ones. The strains which were able to form a stronger biofilm had broader antimicrobial resistance profiles. It was also found that the strongest swarming motility correlated with susceptibility to most antibiotics. The correlations described in this work encourage further investigation of the mechanisms of pathogenicity of P. mirabilis.

Multidrug-Resistant Proteus mirabilis Strain with Cointegrate Plasmid

Proteus mirabilis is a component of the normal intestinal microflora of humans and animals, but can cause urinary tract infections and even sepsis in hospital settings. In recent years, the number of multidrug-resistant P. mirabilis isolates, including the ones producing extended-spectrum β-lactamases (ESBLs), is increasing worldwide. However, the number of investigations dedicated to this species, especially, whole-genome sequencing, is much lower in comparison to the members of the ESKAPE pathogens group. This study presents a detailed analysis of clinical multidrug-resistant ESBL-producing P. mirabilis isolate using short- and long-read whole-genome sequencing, which allowed us to reveal possible horizontal gene transfer between Klebsiella pneumoniae and P. mirabilis plasmids and to locate the CRISPR-Cas system in the genome together with its probable phage targets, as well as multiple virulence genes. We believe that the data presented will contribute to the understanding of antibiotic resistance acquisition and virulence mechanisms for this important pathogen.

Proteus mirabilis causing cellulitis in broiler chickens

Given the need to understand the virulence profile of Proteus mirabilis isolates from cellulitis in broiler chickens and their ability to cause lesions, the present study aimed to characterize genotypically and phenotypically the virulence profiles of two strains of P. mirabilis isolated from cellulitis in broilers, as well as to evaluate their ability to experimentally reproduce the lesions in vivo. The strain with the highest virulence potential (LBUEL-A33) possessed mrpA, pmfA, ucaA, atfA (fimbriae), zapA, ptA (proteases), hpmA (hemolysin), and ireA (siderophore) genes, formed a very strong biofilm, and expressed the pattern of aggregative adhesion and cytotoxicity in Vero cells. The strain with the lowest virulence potential (LBUEL-A34) did not present the pmfA and ucaA genes, but expressed the pattern of aggregative adhesion, formed a strong biofilm, and did not show cytotoxicity. Both strains developed cellulitis in an animal model within 24 h post-inoculation (PI), and the degree of lesions was not significantly altered up to 120 h PI. The LBUEL-A33 strain was also inoculated in combination with an avian pathogenic Escherichia coli (APEC 046), and the lesions showed no significant changes from the individual inoculation of these two strains. Histological analysis showed that the LBUEL-A33 strain developed characteristic cellulitis lesions. Thus, both strains of P. mirabilis isolated in our study have several virulence factors and the ability to develop cellulitis in broilers.

Assessment of Pathogenic Potential, Virulent Genes Profile, and Antibiotic Susceptibility of Proteus mirabilis from Urinary Tract Infection

Proteus mirabilis is the third most common bacterium that can cause complicated UTI, especially in catheterized patients. Urovirulence genes of P. mirabilis strains are poorly identified among UTI patients. The aims of the present study were to determine the prevalence of the uropathogenic P. mirabilis strains isolated from UTI patients by the detection of several P. mirabilis virulence genes and to characterize the antibiotic susceptibility profile of P. mirabilis isolates. P. mirabilis isolates were collected from urine specimens of patients suffering from UTI. Virulence genes in P. mirabilis, namely, hpmA, hpmB, rsbA, luxS, ureC1, hlyA, rpoA, atfA, atfC, mrpA, and pm1 were detected in the isolates via PCR detection method. All P. mirabilis virulence genes were detected in more than 90% of the isolates except hlyA gene, which was detected in only 23.8% of the isolates. The rate of susceptibility for ceftriaxone was 96.8%, followed by norfloxacin (82.5%), gentamicin (71.4%), ciprofloxacin (69.8%), cephalexin (52.4%), nalidixic acid (42.9%), sulfamethoxazole (39.7%), ampicillin (36.5%), and nitrofurantoin (3.2%). Significant associations (P < 0.05) were detected between antimicrobial susceptibility of each of the following antibiotics and the presence virulence genes. Cephalexin antimicrobial susceptibility was significantly associated with the presence each of ureC1 and atfC. Sulfamethoxazole antimicrobial susceptibility was significantly associated with the presence atfA. Ceftriaxone antimicrobial susceptibility was significantly associated with the presence each of hpmA, ureC1, rpoA, atfC, mrpA, and pm1. Nitrofurantoin antimicrobial susceptibility was significantly associated with the presence each of hpmA, ureC1, rpoA, atfA, atfC, mrpA, and pm1. In conclusion, an association between the presence of urovirulence genes of P. mirabilis and increasing P. mirabilis resistance to antimicrobials has been demonstrated.

The Role of Gram-Negative Bacteria in Urinary Tract Infections: Current Concepts and Therapeutic Options

Urinary tract infections (UTIs) are some of the most common infections in human medicine worldwide, recognized as an important public health concern to healthcare systems around the globe. In addition, urine specimens are one of the most frequently submitted samples for culture to the clinical microbiology laboratory, exceeding the number of most of the other sample types. The epidemiology, species-distribution and susceptibility-patterns of uropathogens vary greatly in a geographical and time-dependent manner and it also strongly correlated with the reported patient population studied. Nevertheless, many studies highlight the fact that the etiological agents in UTIs have changed considerably, both in nosocomial and community settings, with a shift towards "less common" microorganisms having more pronounced roles. There is increasing demand for further research to advance diagnostics and treatment options, and to improve care of the patients. The aim of this review paper was to summarize current developments in the global burden of UTI, the diagnostic aspects of these infectious pathologies, the possible etiological agents and their virulence determinants (with a special focus on the members of the Enterobacterales order), current guidelines and quality indicators in the therapy of UTIs and the emergence of multidrug resistance in urinary pathogens.

Explication of the Potential of 2-Hydroxy-4-Methoxybenzaldehyde in Hampering Uropathogenic Proteus mirabilis Crystalline Biofilm and Virulence

Proteus mirabilis is an important etiological agent of catheter-associated urinary tract infections (CAUTIs) owing to its efficient crystalline biofilm formation and virulence enzyme production. Hence, the present study explicated the antibiofilm and antivirulence efficacies of 2-hydroxy-4-methoxybenzaldehyde (HMB) against P. mirabilis in a non-bactericidal manner. HMB showed concentration-dependent biofilm inhibition, which was also evinced in light, confocal, and scanning electron microscopic (SEM) analyses. The other virulence factors such as urease, hemolysin, siderophores, and extracellular polymeric substances production as well as swimming and swarming motility were also inhibited by HMB treatment. Further, HMB treatment effectively reduced the struvite/apatite production as well as crystalline biofilm formation by P. mirabilis. Furthermore, the results of gene expression analysis unveiled the ability of HMB to impair the expression level of virulence genes such as flhB, flhD, rsbA, speA, ureR, hpmA, and hpmB, which was found to be in correlation with the results of in vitro bioassays. Additionally, the cytotoxicity analysis divulged the innocuous characteristic of HMB against human embryonic kidney cells. Thus, the present study reports the potency of HMB to act as a promising therapeutic remedy for P. mirabilis-instigated CAUTIs.

Genotypic and phenotypic profiles of virulence factors and antimicrobial resistance of Proteus mirabilis isolated from chicken carcasses: potential zoonotic risk

Proteus mirabilis is an opportunistic pathogen often associated with a variety of human infections acquired both in the community and in hospitals. In this context, the present work aimed to evaluate the genotypic and phenotypic characteristics of the virulence factors and antimicrobial resistance determinants of 32 P. mirabilis strains isolated from chicken carcasses in a poultry slaughterhouse in the north of the state of Paraná, Brazil, in order to assess a potential zoonotic risk. The isolates presented a variety of virulence genes that contribute to the development of infection in humans. The mrpA, pmfA, atfA (fimbriae), ireA (siderophores receptor), zapA, ptA (Proteases), and hpmA (hemolysin) genes were found in 32 (100%) isolates and ucaA (fimbriae) in 16 (50%). All isolates showed aggregative adherence in HEp-2 cells and formed biofilms. Of all strains, 27 (84.38%) showed cytotoxic effects in Vero cells. Antimicrobial susceptibility was tested using 20 antimicrobials, in which 25 (78.13%) strains were considered multidrug-resistant. The presence of blaESBL and blaampC genes conferring resistance to β-lactams and qnr to quinolones were also detected in the isolates after presumption in the phenotypic test, in which 7 (21.88%) isolates contained the CTX-M-2 group, 11 (34.38%) contained CIT group and 19 (59.38%) contained qnrD. Therefore, chicken carcasses contaminated with P. mirabilis may pose a health risk to the consumer, as these isolates have a variety of virulence and antimicrobial resistance characteristics that can be found in P. mirabilis strains isolated from human infections.

Pathogenesis of Proteus mirabilis Infection

Proteus mirabilis, a Gram-negative rod-shaped bacterium most noted for its swarming motility and urease activity, frequently causes catheter-associated urinary tract infections (CAUTIs) that are often polymicrobial. These infections may be accompanied by urolithiasis, the development of bladder or kidney stones due to alkalinization of urine from urease-catalyzed urea hydrolysis. Adherence of the bacterium to epithelial and catheter surfaces is mediated by 17 different fimbriae, most notably MR/P fimbriae. Repressors of motility are often encoded by these fimbrial operons. Motility is mediated by flagella encoded on a single contiguous 54-kb chromosomal sequence. On agar plates, P. mirabilis undergoes a morphological conversion to a filamentous swarmer cell expressing hundreds of flagella. When swarms from different strains meet, a line of demarcation, a "Dienes line," develops due to the killing action of each strain's type VI secretion system. During infection, histological damage is caused by cytotoxins including hemolysin and a variety of proteases, some autotransported. The pathogenesis of infection, including assessment of individual genes or global screens for virulence or fitness factors has been assessed in murine models of ascending urinary tract infections or CAUTIs using both single-species and polymicrobial models. Global gene expression studies performed in culture and in the murine model have revealed the unique metabolism of this bacterium. Vaccines, using MR/P fimbria and its adhesin, MrpH, have been shown to be efficacious in the murine model. A comprehensive review of factors associated with urinary tract infection is presented, encompassing both historical perspectives and current advances.

Incidence of antibiogram, antibiotic resistance genes and class 1 and 2 integrons in tribe Proteeae with IMP27 gene for the first time in Providencia sp. isolated from pet turtles

Proteeae is a tribe which consists of three genera: Proteus, Providencia and Morganella. The objective of this study was to determine antimicrobial resistance profile, virulence genotype and class 1 and 2 integrons in Proteeae isolated from pet turtles and to determine the impact of antibiotic resistance on virulence and antimicrobial resistance genes. Integron-positive isolates were used to detect their gene cassette array. Sixty four Proteeae were isolated and all were resistant to macrolides (100%). Among 64 isolates 56, 52, 36 and 25 were resistant to nitrofurans, β-lactams, tetracycline and aminoglycoside respectively. Sixteen (25%) isolates were positive for intI1 while 14 (21·87%) were positive for integrase 2 (intI2). Eleven (17·18%) isolates were positive for class 1 variable region while 7 (10·93%) were positive for class 2 variable region. IMP27, a novel metallo β-lactamase gene was found in Providencia isolates. Proteus sp. were positive for every tested virulence genes and UreC gene was detected in 48·44% followed by zapA (17·19%), mrpA (17·19%) and hlyA (14·06%) genes. In this study, integron associated-antibiotic resistance genes have been identified in Proteeae isolates in a considerable range representing clear threats to public health. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, multidrug-resistant Proteeae isolates had several antibiotic resistance genes. Integrons are important contributors to the development and dissemination of antibiotic resistance. We could detect both class 1 and 2 integrons and several gene cassette arrays in class 1 integron. The gene cassette arrays of the Class 2 integrons contained IMP27-dfrA1-aadA1-catB2-ybeA-ybgA in two isolates. To the best of our knowledge this is the first study to report detection of IMP27 in Providencia rettgeri isolates. All results indicate that healthy pet turtles act as potential reservoirs for Proteeae species with zoonotic potential.

Proteus spp. as Putative Gastrointestinal Pathogens

Proteus species, members of the Enterobacteriaceae family, are usually considered commensals in the gut and are most commonly recognized clinically as a cause of urinary tract infections. However, the recent identification of Proteus spp. as potential pathogens in Crohn's disease recurrence after intestinal resection serves as a stimulus to examine their potential role as gut pathogens. Proteus species possess many virulence factors potentially relevant to gastrointestinal pathogenicity, including motility; adherence; the production of urease, hemolysins, and IgA proteases; and the ability to acquire antibiotic resistance. Gastrointestinal conditions that have been linked to Proteus include gastroenteritis (spontaneous and foodborne), nosocomial infections, appendicitis, colonization of devices such as nasogastric tubes, and Crohn's disease. The association of Proteus species with Crohn's disease was particularly strong. Proteus species are low-abundance commensals of the human gut that harbor significant pathogenic potential; further investigation is needed.

Emerging medical and engineering strategies for the prevention of long-term indwelling catheter blockage

Urinary catheters have been used on an intermittent or indwelling basis for centuries, in order to relieve urinary retention and incontinence. Nevertheless, the use of urinary catheters in the clinical setting is fraught with complication, the most common of which is the development of nosocomial urinary tract infections, known as catheter-associated urinary tract infections. Infections of this nature are not only significant owing to their high incidence rate and subsequent economic burden but also to the severe medical consecutions that result. A range of techniques have been employed in recent years, utilising various technologies in attempts to counteract the perilous medical cascade following catheter blockage. This review will focus on the current advancement (within the last 10 years) in prevention of encrustation and blockage of long-term indwelling catheters both from engineering and medical perspectives, with particular emphasis on the importance of stimuli-responsive systems.

Proteus mirabilis and Urinary Tract Infections

Proteus mirabilis is a Gram-negative bacterium and is well known for its ability to robustly swarm across surfaces in a striking bulls'-eye pattern. Clinically, this organism is most frequently a pathogen of the urinary tract, particularly in patients undergoing long-term catheterization. This review covers P. mirabilis with a focus on urinary tract infections (UTI), including disease models, vaccine development efforts, and clinical perspectives. Flagella-mediated motility, both swimming and swarming, is a central facet of this organism. The regulation of this complex process and its contribution to virulence is discussed, along with the type VI-secretion system-dependent intra-strain competition, which occurs during swarming. P. mirabilis uses a diverse set of virulence factors to access and colonize the host urinary tract, including urease and stone formation, fimbriae and other adhesins, iron and zinc acquisition, proteases and toxins, biofilm formation, and regulation of pathogenesis. While significant advances in this field have been made, challenges remain to combatting complicated UTI and deciphering P. mirabilis pathogenesis.

Comparative Screening of Digestion Tract Toxic Genes in Proteus mirabilis

Proteus mirabilis is a common urinary tract pathogen, and may induce various inflammation symptoms. Its notorious ability to resist multiple antibiotics and to form urinary tract stones makes its treatment a long and painful process, which is further challenged by the frequent horizontal gene transferring events in P. mirabilis genomes. Three strains of P. mirabilis C02011/C04010/C04013 were isolated from a local outbreak of a food poisoning event in Shenzhen, China. Our hypothesis is that new genes may have been acquired horizontally to exert the digestion tract infection and toxicity. The functional characterization of these three genomes shows that each of them independently acquired dozens of virulent genes horizontally from the other microbial genomes. The representative strain C02011 induces the symptoms of both vomit and diarrhea, and has recently acquired a complete type IV secretion system and digestion tract toxic genes from the other bacteria.

Urinary tract infections: epidemiology, mechanisms of infection and treatment options

Urinary tract infections (UTIs) are a severe public health problem and are caused by a range of pathogens, but most commonly by Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis and Staphylococcus saprophyticus. High recurrence rates and increasing antimicrobial resistance among uropathogens threaten to greatly increase the economic burden of these infections. In this Review, we discuss how basic science studies are elucidating the molecular details of the crosstalk that occurs at the host-pathogen interface, as well as the consequences of these interactions for the pathophysiology of UTIs. We also describe current efforts to translate this knowledge into new clinical treatments for UTIs.