Phenotypic and genotypic characteristics of Escherichia coli strains isolated during a longitudinal follow-up study of chronic urinary tract infections.

Worldwide, Urinary Tract Infections (UTIs) are an important health problem with many cases reported annually, women being the most affected. UTIs are relevant because they can become a recurrent condition, associated with different factors that contribute to the chronicity of the disease (cUTI). cUTI can be classified as persistent (peUTI) when the causative agent is the same each time the infection occurs or as reinfection (reUTI) when the associated microorganism is different. The purpose of this work was to characterize Escherichia coli isolates obtained in two prospective studies of patients with cUTI, to define which of them corresponded to peUTI and which to reUTI. A total of 394 isolates of E. coli were analyzed by agglutination with specific sera, antimicrobial susceptibility by diffusion disc test, and the phylogroups and presence of genes associated with virulence by PCR assays. Additionally, in some characterized strains adherence, invasiveness, and biofilm formation were analyzed by in vitro assays. The results showed that the peUTI strains belonged mainly to the classical UPEC serogroups (O25, O75, O6), were included in the B2 phylogroup, carried a great number of virulence genes, and were adherent, invasive, and biofilm-forming. Meanwhile, reUTI strains showed great diversity of serogroups, belonged mainly in the A phylogroup, and carried fewer virulence genes. Both peUTI and reUTI strains showed extensively drug-resistant (XDR) and multidrug-resistant (MDR) profiles in the antimicrobial susceptibility test. In conclusion, it appears that peUTIs are caused principally by classical UPEC strains, while reUTIs are caused by strains that appear to be a part of the common E. coli intestinal biota. Moreover, although both peUTI and reUTI strains presented different serotypes and phylogroups, their antimicrobial resistance profile (XDR and MDR) was similar, confirming the importance of regulating prophylactic treatments and seeking alternatives for the treatment and control of cUTI. Finally, it was possible to establish the features of the E. coli strains responsible for peUTI and reUTI which could be helpful to develop a fast diagnostic methodology.

Correlation Between Antimicrobial Resistance And Virulence Genes In Klebsiella Pneumoniae Isolates From Egypt.

Objectives: To genotypically assess the relationship between certain resistance and virulence determinants. Method: The cross-sectional study was conducted at Kafrelsheikh University, Egypt, from March 2019 to May 2021, and comprised pathologicalsamples, like blood,sputum, urine, vaginalswabs and wound swabs, that had been taken from patients who had never received treatment. The sample were collected from Kafrelsheikh and Mansoura University hospitals, and Klebsiella pneumoniae isolates were obtained. Resistance and virulence determinants were tested phenotypically. Uniplex polymerase chain reaction was used to evaluate the presence of several resistance accompanied genes and virulence genes in the isolates. Disc diffusion method was used to assess the isolates' susceptibility in accordance with the Clinical and Laboratory Standards Institute criteria for identifying diverse resistance patterns. RESULTS: There were 23 isolatesfrom 16 patients. Of the tested isolates, 22(95.65%)showed drug resistance; 19(82.6%) had multidrug resistance, and 3(13.04%) had extensive drug resistance. There was no case of pan drug resistance. CTX-M-15, NDM, CTX-M-1, VIM-1 and qnr B genes were detected in 14(60.86%), 13(56.5%), 6(26.08%), 6(26.08%) and 6(26.08%) isolates, respectively. Moreover, 6(26.08%) isolates exhibited extended-spectrum ß-lactamase producers, and 12(52.17%) ofsuch isolates contained both CTX-M-1 and CTX-M-15 genes, 6 and 33.3% contained CTX-M-1, CTX M-15 and fox genes. Type 3 fimbriae adhesin mrkD and mucoviscosity regulatory gene uge were found in the tested isolates. However, gene of iron uptake system kfu wasfound in 8(34.78%) isolates, and increased serum survival protein is and mucoviscosity accompanied gene magA were detected in 3(13.04%) isolates. A direct correlation was found among 5 from 8 Klebsiella pneumoniae virulence genes and antimicrobial resistance genes. CONCLUSIONS: There was a direct correlation between the existence of virulence factors and resistance to antimicrobials.

Isolation and Purification of Mycobacterial Extracellular Vesicles (EVs).

Bacterial extracellular vesicles (EVs) contain numerous active substances that mediate bacterial interactions with their host and with other microbes. Best defined are the EVs from Gram-negative bacteria that have been shown to deliver virulence factors, modulate the immune responses, mediate antibiotic resistance, and also inhibit competitive microbes. Due to the complex cell wall structures of Gram-positive bacteria and mycobacteria, EVs from these bacteria were only recently reported. This protocol describes the isolation of EVs from mycobacteria.

[Investigation of Virulence Genes and Carbapenem Resistance Genes in Hypervirulent and Classical Isolates of Klebsiella pneumoniae Isolated from Various Clinical Specimens]. / Çesitli Klinik Örneklerden Izole Edilen Hipervirülan ve Klasik Klebsiella pneumoniae Izolatlarinda Virülans Genleri ve Karbapenem Direnç Genlerinin Arastirilmasi.

Klebsiella pneumoniae is a global pathogen that can cause hospital-acquired and community-acquired infections and is known for its resistance to antibiotics. The pathotype, which is defined as hypervirulent K.pneumoniae (hvKp) is more lethal than classical K.pneumoniae (cKp) isolates and causes many community-acquired infections such as liver abscess, endophthalmitis, pneumonia in healthy young adults. There are no clear clinical or microbiological criteria to define hvKp. String test showing hypermucoviscosity and the iucA gene encoding aerobactin, a siderophore, were used to demonstrate hypervirulence. In this study, it was aimed to investigate the presence of various virulence genes and carbapenem resistance genes in the isolates of K.pneumoniae isolated from various clinical samples in our laboratory and classified as classical and hypervirulent by string test and also to detect the presence of various virulence and carbapenem resistance genes in hvKp isolates. Presence of four virulence genes (fimH-1, rmpA, magA, iucA), K1-K2 serotypes in all isolates and five carbapenem resistance genes (blaOXA-48, blaKPC, blaIMP, blaVIM, blaNDM-1) in carbapenem resistant isolates were investigated with polymerase chain reaction (PCR) method. Forty-five percent of the isolates were defined as hvKp and 55% as cKp. The fimH-1 gene was found to be positive in 94% of the isolates, the iucA gene in 37%, the magA gene (K1) in 34%, the rmpA gene in 5%, and the K2 serotype in 3% of the isolates. iucA gene was positive in 68.9% of hvKp isolates and 10.9% of cKp isolates, and the presence of iucA gene in hvKp isolates was statistically significant compared to cKp isolates (p<0.05). magA gene and K1 serotype were detected in 28.9% of hvKp isolates and 38.2% of cKp isolates. Although the magA gene ratio was high in cKp isolates, this difference was not statistically significant (p> 0.05). fimH-1 gene was found positive in 93.3% of hvKp isolates and 94.5% of cKp isolates. The rmpA gene was positive in 8.9% of hvKp isolates and 1.8% of cKp isolates. The K2 serotype was positive in 4.4% of hvKp isolates and 1.8% of cKp isolates. Although there was no statistical difference in antibiotic susceptibility between hvKp and cKp isolates; ceftriaxone, cefuroxime, ceftazidime, amikacin, cefoxitin, ertapenem, cefuroxime axetil were found to be more sensitive in hvKp isolates. Ciprofloxacin and trimethoprim sulfamethoxazole were found to be more sensitive in hvKp isolates than cKp isolates, and the difference was statistically significant (p<0.05). Although gentamicin, amoxicillin, piperacillintazobactam were not statistically significant in the cKp group, they were more sensitive than the hvKp group (p> 0.05). Carbapenem resistance were found to be 65.7% in cKp and 34.3% in hvKp isolates. Although not statistically significant, hvKp isolates were found to be more sensitive to carbapenems. The most common gene among 35 carbapenem resistant isolates was blaOXA-48 detected in 29 isolates. While the blaKPC gene was detected in five isolates, blaIMP, blaVIM and blaNDM-1 were not detected in any isolates. Sixty nine percent of blaOXA-48 positive samples were found to be in cKp isolates and 31% in hvKp isolates. It was determined that all of the blaKPC positive isolates were hvKp isolates. It was concluded that the string test and virulence factors alone would not be sufficient to show hypervirulence, and that more than one virulence factor combination should be shown in the presence of clinical features of hypervirulent infections to show hypervirulence.

Virulence and antibiotic-resistance genes in Enterococcus faecalis associated with streptococcosis disease in fish.

Enterococcus faecalis is associated with streptococcosis like infection in fish. A whole-genome sequence study was conducted to investigate the virulence factor and antibiotic-resistance genes in three fish pathogenic E. faecalis. Genomic DNA was extracted from three strains of E. faecalis isolated from streptococcosis infected Nile tilapia (strains BF1B1 and BFFF11) and Thai sarpunti (strain BFPS6). The whole genome sequences of these three strains were performed using a MiSeq sequencer (Illumina, Inc.). All three strains conserved 69 virulence factor such as genes associated with protection against oxidative stress, bacterial cell wall synthesis, gelatinase toxin, multiple biofilm-associated genes and capsule producing genes. Moreover, 39 antibiotic-resistance genes against sixteen major groups of antibiotics were identified in the genome sequences of all three strains. The most commonly used antibiotic Tetracycline resistance genes were found only in BFPS6 strain, whereas, Bacteriocin synthesis genes were identified in both BFFF11 and BFPS6 strain. Phylogenetic analysis revealed that strains BF1B1 and BFFF1 form a different cluster than BFPS6. This is one of the first whole-genome sequence study of fish pathogenic E. faecalis, unfold new information on the virulence factor and Antibiotic resistance genes linked to pathogenicity in fish.

Genomic Analysis of Shiga Toxin-Producing E. coli O157 Cattle and Clinical Isolates from Alberta, Canada.

Shiga toxin (stx) is the principal virulence factor of the foodborne pathogen, Shiga toxin-producing Escherichia coli (STEC) O157:H7 and is associated with various lambdoid bacterio (phages). A comparative genomic analysis was performed on STEC O157 isolates from cattle (n = 125) and clinical (n = 127) samples to characterize virulence genes, stx-phage insertion sites and antimicrobial resistance genes that may segregate strains circulating in the same geographic region. In silico analyses revealed that O157 isolates harboured the toxin subtypes stx1a and stx2a. Most cattle (76.0%) and clinical (76.4%) isolates carried the virulence gene combination of stx1, stx2, eae and hlyA. Characterization of stx1 and stx2-carrying phages in assembled contigs revealed that they were associated with mlrA and wrbA insertion sites, respectively. In cattle isolates, mlrA and wrbA insertion sites were occupied more often (77% and 79% isolates respectively) than in clinical isolates (38% and 1.6% isolates, respectively). Profiling of antimicrobial resistance genes (ARGs) in the assembled contigs revealed that 8.8% of cattle (11/125) and 8.7% of clinical (11/127) isolates harboured ARGs. Eight antimicrobial resistance genes cassettes (ARCs) were identified in 14 isolates (cattle, n = 8 and clinical, n = 6) with streptomycin (aadA1, aadA2, ant(3'')-Ia and aph(3'')-Ib) being the most prevalent gene in ARCs. The profound disparity between the cattle and clinical strains in occupancy of the wrbA locus suggests that this trait may serve to differentiate cattle from human clinical STEC O157:H7. These findings are important for stx screening and stx-phage insertion site genotyping as well as monitoring ARGs in isolates from cattle and clinical samples.

Molecular typification of Escherichia coli from community-acquired urinary tract infections in Mexico.

One hundred and five uropathogenic Escherichia coli (UPEC) strains from patients with community-acquired urinary tract infections were characterized according to phylogenetic group, virulence factors, serogroup, antibiotic resistance, and genotype. The pathogenic phylogenetic groups (B2, D, and F) were found in 71.4% of the tested strains. Among them, the main uropathogenic serogroups were O8, O25, and O75, in which 97.1% of the strains had a multidrug-resistant profile. Sixteen virulence genes were analysed using a combination of polymerase chain reaction (PCR) assays, with the fimH, irp-2, iutA, aer, iucC, PAI, sat, iroN, usp, and cnf1 genes being mainly found in pathogenic phylogroups. The E. coli O25b-ST131 clone was identified in 32% of the strains assigned to the pathogenic phylogroup B2. These findings demonstrate that virulence genes encoding adhesin components, iron-acquisition systems, toxins, and pathogenicity-associated islands were highly prevalent among the pathogenic phylogroup of UPEC strains.

Characterization of Pili Protein 67 kDa Streptococcus pneumoniae: New Candidate for Virulence Factor-Based Pneumococcal Antigen Vaccine.

INTRODUCTION: Streptococcus pneumoniae is a Gram-positive diplococci bacteria that causes infectious diseases such as otitis, meningitis, and pneumonia. Streptococcus pneumoniae has various virulence factors, one of which is pilus. In addition to being immunogenic, pilus S. pneumoniae also plays a role in bacterial adhesion to host cells and biofilm formation. The S. pneumoniae pilus found in this study consisted of several proteins with various molecular weights, one of which was a 67 kDa protein. OBJECTIVE: This study aimed to determine the characteristics of the 67 kDa pilus protein, including its capacity as hemagglutinin and adhesin and its amino acid sequence (AA). METHODS: The LCMS/MS method is used to determine the AA sequence of the 67 kDa pilus protein. The AA structure was analyzed through BLASTP by matching it with the sequence of the protein data bank of S. pneumoniae (taxid: 1313). The ProtParam tool from ExPASY was used to calculate various physical and chemical parameters of the protein, while for evaluating its immunogenicity, the VaxiJen V2.0 online server was used. RESULTS: The results of this study indicate that the 67 kD a pilus protein, is an anti-hemagglutinin protein and has a role as an adhesin protein. Adhesion tests show the action between protein concentration and the number of bacteria attached to enterocyte cells. LCMS/MS test results obtained by BLASTP showed that the 67 kDa pilus protein had three AA sequences (ITYMSPDFAAPTLAGLDDATK, AEFVEVTK, and LVVSTQTALA), which had similarities with the A backbone chain of S. pneumoniae pilus. The physicochemical test showed that the protein is hydrophilic and nonpolar, while the antigenicity test showed that the protein is antigenic. CONCLUSION: Based on these characteristics, it can be concluded that the 67 kDa S. pneumoniae pilus protein can be used as a vaccine candidate for pneumococcus.

Bacterial pore-forming toxins.

Pore-forming toxins (PFTs) are widely distributed in both Gram-negative and Gram-positive bacteria. PFTs can act as virulence factors that bacteria utilise in dissemination and host colonisation or, alternatively, they can be employed to compete with rival microbes in polymicrobial niches. PFTs transition from a soluble form to become membrane-embedded by undergoing large conformational changes. Once inserted, they perforate the membrane, causing uncontrolled efflux of ions and/or nutrients and dissipating the protonmotive force (PMF). In some instances, target cells intoxicated by PFTs display additional effects as part of the cellular response to pore formation. Significant progress has been made in the mechanistic description of pore formation for the different PFTs families, but in several cases a complete understanding of pore structure remains lacking. PFTs have evolved recognition mechanisms to bind specific receptors that define their host tropism, although this can be remarkably diverse even within the same family. Here we summarise the salient features of PFTs and highlight where additional research is necessary to fully understand the mechanism of pore formation by members of this diverse group of protein toxins.

Selection of Debaryomyces hansenii isolates as starters in meat products based on phenotypic virulence factors, tolerance to abiotic stress conditions and aroma generation.

INTRODUCTION: Debaryomyces hansenii is a yeast widely used in meat fermentations as starter for the purpose of improving the aromatic quality of the final product. However, it has not been the subject of an extensive study regarding phenotypic characteristics important for starter selection, such as the capacity to grow at abiotic stress conditions occurring during fermentation, the ability to generate desirable aromas and the absence of virulence traits in yeasts. AIMS: The aim of this study was to screen 60 strains of D. hansenii isolated from assorted foods for their potential application as starters in dry-cured fermented sausages manufacture. METHODS: The abiotic stress factors tested were low aw and pH and high concentration of salt, acetic acid and lactic acid. The phenotypic virulence traits explored were growth at 37°C, pseudohyphal and biofilm generation, invasiveness and enzymatic activities present in virulent yeasts. The generation of desirable meat aromas was tested in models containing aroma precursors applying an olfactory analysis. A quantitative profiling of stress tolerance was used to test the potential performance of selected strains in meat fermentations. RESULTS: The results demonstrated that most strains displayed no virulence trait or were only positive for biofilm production. Moreover, the strains showed large heterogeneity regarding their tolerance to abiotic stress factors, although most of them could grow at intermediate to high levels of the traits. The sensory analysis was the criteria determining the selection of starter strains. CONCLUSIONS: The evaluation of the phenotypic traits demonstrates that D. hansenii is a safe yeast, it is able to tolerate the stress in meat fermentation and it is able to generate desirable aromas. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study confirm the adequacy of selected D. hansenii strains to be applied as starters in meat products.

Epidemiologic potentials and correlational analysis of Vibrio species and virulence toxins from water sources in greater Bushenyi districts, Uganda.

Adequate water supply is one of the public health issues among the population living in low-income settings. Vibriosis remain a significant health challenge drawing the attention of both healthcare planners and researchers in South West districts of Uganda. Intending to clamp down the disease cases in the safest water deprive locality, we investigated the virulent toxins as contaminants and epidemiologic potentials of Vibrio species recovered from surface waters in greater Bushenyi districts, Uganda. Surface water sources within 46 villages located in the study districts were obtained between June and October 2018. Standard microbiological and molecular methods were used to analyse samples. Our results showed that 981 presumptive isolates retrieved cell counts of 10-100 CFU/g, with, with (640) 65% confirmed as Vibrio genus using polymerase chain reaction, which is distributed as follows; V. vulnificus 46/640 (7.2%), V. fluvialis 30/594 (5.1), V. parahaemolyticus 21/564 (3.7), V. cholera 5/543 (0.9), V. alginolyticus 62/538 (11.5) and V. mimicus 20/476 (4.2). The virulence toxins observed were heat-stable enterotoxin (stn) 46 (82.10%), V. vulnificus virulence gene (vcgCPI) 40 (87.00%), extracellular haemolysin gene {vfh 21 (70.00)} and Heme utilization protein gene {hupO 5 (16.70)}. The cluster analysis depicts hupO (4.46% n = 112); vfh (18.75%, n = 112); vcgCPI and stn (35.71%, & 41.07%, n = 112). The principal component analysis revealed the toxins (hupO, vfh) were correlated with the isolate recovered from Bohole water (BW) source, while (vcgCPI, stn) toxins are correlated with natural raw water (NRW) and open springs (OS) water sources isolates. Such observation indicates that surface waters sources are highly contaminated with an odds ratio of 1.00, 95% CI (70.48-90.5), attributed risk of (aR = 64.29) and relative risk of (RR = 73.91). In addition, it also implies that the surface waters sources have > 1 risk of contamination with vfh and > six times of contamination with hupO (aR = 40, - 66). This is a call of utmost importance to the population, which depends on these water sources to undertake appropriate sanitation, personal hygienic practices and potential measures that ensure water quality.

Novel strains of Klebsiella africana and Klebsiella pneumoniae in Australian fruit bats (Pteropus poliocephalus).

Over the past decade human associated multidrug resistant (MDR) and hypervirulent Klebsiella pneumoniae lineages have been increasingly detected in wildlife. This study investigated the occurrence of K. pneumoniae species complex (KpSC) in grey-headed flying foxes (GHFF), an Australian fruit bat. Thirty-nine KpSC isolates were cultured from 275 GHFF faecal samples (14.2%), comprising K. pneumoniae (n = 30), Klebsiella africana (n = 8) and Klebsiella variicola subsp. variicola (n = 1). The majority (79.5%) of isolates belonged to novel sequence types (ST), including two novel K. africana STs. This is the first report of K. africana outside of Africa and in a non-human host. A minority (15.4%) of GHFF KpSC isolates shared STs with human clinical K. pneumoniae strains, of which, none belonged to MDR clonal lineages that cause frequent nosocomial outbreaks, and no isolates were characterised as hypervirulent. The occurrence of KpSC isolates carrying acquired antimicrobial resistance genes in GHFF was low (1.1%), with three K. pneumoniae isolates harbouring both fluoroquinolone and trimethoprim resistance genes. This study indicates that GHFF are not reservoirs for MDR and hypervirulent KpSC strains, but they do carry novel K. africana lineages. Health risks associated with KpSC carriage by GHFF are deemed low for the public and GHFF.

Detection and Quantification of Secreted Nuclease Activity in Staphylococcus aureus Culture Supernatants.

Staphylococcal secreted nuclease contributes to S. aureus virulence by degrading neutrophil extracellular traps (NETs), which allows the bacterium to evade the host immune system and has also been shown to promote biofilm dispersal. In this chapter, two methods for detecting nuclease activity are described, both of which have increased sensitivity compared to the traditional nuclease agar method.

Quantitative Hemolysis Assays.

Many strains of Staphylococcus aureus produce a variety of cytolysins that target many different cell types to both fight the immune system and acquire nutrients. This includes hemolysins which destroy erythrocytes and are well studied virulence factors. Traditionally, hemolysin activity is measured on blood agar plates due to the simplicity of the assay. While this is telling, it cannot encapsulate the full story because S. aureus is known to behave differently in broth and on agar. Furthermore, plate-based assays are primarily semiquantitative and often a more accurate determination of hemolytic potential is needed to discern differences between strains. Here, we describe a method to quantify hemolysin activity from broth or similarly grown cells.

Listeria monocytogenes: review of pathogenesis and virulence determinants-targeted immunological assays.

Listeria monocytogenes is one of the most invasive foodborne pathogens and is responsible for numerous outbreaks worldwide. Most of the methods to detect this bacterium in food require selective enrichment using traditional bacterial culture techniques that can be time-consuming and labour-intensive. Moreover, molecular methods are expensive and need specific technical knowledge. In contrast, immunological approaches are faster, simpler, and user-friendly alternatives and have been developed for the detection of L. monocytogenes in food, environmental, and clinical samples. These techniques are dependent on the constitutive expression of L. monocytogenes antigens and the specificity of the antibodies used. Here, updated knowledge on pathogenesis and the key immunogenic virulence determinants of L. monocytogenes that are used for the generation of monoclonal and polyclonal antibodies for the serological assay development are summarised. In addition, immunological approaches based on enzyme-linked immunosorbent assay, immunofluorescence, lateral flow immunochromatographic assays, and immunosensors with relevant improvements are highlighted. Though the sensitivity and specificity of the assays were improved significantly, methods still face many challenges that require further validation before use.

Resistencia antimicrobiana y factores de virulencia en aislados de Vibrio cholerae O1. Cuba, 2012-2015 / Antimicrobial resistance and virulence factors in Vibrio cholerae O1 isolates. Cuba, 2012-2015

Introducción: El cólera es una infección intestinal aguda causada por cepas toxigénicas de Vibrio choleare. La rápida diseminación y emergencia de la multirresistencia que caracteriza a este patógeno, podría interferir en el éxito de la terapia antimicrobiana, por lo que constituye una prioridad monitorear los cambios en los patrones de susceptibilidad, como parte trascendental de la política de control de la resistencia antimicrobiana. Objetivo: Determinar el comportamiento de la resistencia antimicrobiana frente a los antimicrobianos de interés empleados en el tratamiento, la presencia de factores de virulencia enzimáticos y si existe relación entre ambos. Métodos: Se realizó un estudio descriptivo de corte transversal durante julio de 2012 a diciembre de 2015. Se estudiaron 500 aislamientos pertenecientes al cepario del Laboratorio Nacional de Referencia de Enfermedades Diarreicas Agudas del Instituto de Medicina Tropical Pedro Kourí, procedentes de brotes de enfermedades diarreicas agudas de la red nacional de laboratorios de Microbiología de Cuba. Se aplicaron métodos convencionales fenotípicos para determinar el comportamiento de la resistencia antimicrobiana, la presencia de factores enzimáticos y la relación de estos con la resistencia antimicrobiana. Resultados: Los mayores porcentajes de sensibilidad se obtuvieron frente a azitromicina (98 por ciento), doxiciclina (96 por ciento) y ciprofloxacina (93 por ciento) y de resistencia frente a ampicilina (100 por ciento) y trimetoprim-sulfametoxazol (99,4 por ciento). Se encontraron 44 aislados (8,8 por ciento) multirresistente. Todos los aislamientos poseían al menos dos enzimas extracelulares como factores de virulencia, las más frecuentes: gelatinasa (96 por ciento) y lecitinasa (95 por ciento). Conclusiones: Se evidencia una relación directa y proporcional entre la presencia de los factores de virulencia y resistencia antimicrobiana, sinergismo que surgiere mayor patogenicidad de los aislados estudiados procedentes de brotes epidémicos(AU)

Introduction: Cholera is an acute intestinal infection caused by toxigenic strains of Vibrio choleare. The rapid dissemination and emergence of the multiresistance that characterizes this pathogen could interfere with the success of antimicrobial therapy, so it is a priority to monitor changes in susceptibility patterns, as a transcendental part of the resistance control policy antimicrobial. Objective: To determine the behavior of antimicrobial resistance against the antimicrobials of interest used in the treatment, the presence of enzymatic virulence factors and whether there is a relationship between them. Methods: A descriptive cross-sectional study was conducted during July 2012 to December 2015. Where 500 isolates belonging to the cepary of the National Reference Laboratory for Acute Diarrheal Diseases of the Institute of Tropical Medicine Pedro Kourí, from outbreaks of EDA of the national network of Microbiology laboratories in Cuba. Conventional phenotypic methods were applied to determine the behavior of antimicrobial resistance, the presence of enzymatic factors and their relationship with antimicrobial resistance. Results: The highest percentages of sensitivity were obtained against azithromycin (98 percent), doxycycline (96 percent) and ciprofloxacin (93 percent) and resistance to ampicillin (100 percent) and trimethoprim-sulfamethoxazole (99.4 percent). 44 isolated (8.8 percent) multi-resistant were found. All isolates had at least two extracellular enzymes as virulence factors, the most frequent: gelatinase (96 percent) and lecithinase (95 percent). Conclusions: There is a direct and proportional relationship between the presence of virulence factors and antimicrobial resistance, synergism that arises greater pathogenicity of the isolates studied from epidemic outbreaks(AU)

Galleria mellonella as a screening tool to study virulence factors of Aspergillus fumigatus.

The invertebrate Galleria mellonella has increasingly and widely been used in the last few years to study complex host-microbe interactions. Aspergillus fumigatus is one of the most pathogenic fungi causing life-threatening diseases in humans and animals. Galleria mellonella larvae has been proven as a reliable model for the analysis of pathogenesis and virulence factors, enable to screen a large number of A. fumigatus strains. This review describes the different uses of G. mellonella to study A. fumigatus and provides a comparison of the different protocols to trace fungal pathogenicity. The review also includes a summary of the diverse mutants tested in G. mellonella, and their respective contribution to A. fumigatus virulence. Previous investigations indicated that G. mellonella should be considered as an interesting tool even though a mammalian model may be required to complete and verify initial data.

Multiresistance and virulence factors of Staphylococcus aureus isolated from pigs / [Multirresistência e fatores de virulência de Staphylococcus aureus isolados de suínos]

The emergence of livestock-associated methicillin-resistant Staphylococcus aureus strains (LA-MRSA) and the potential role of pigs in the evolution of these strains has led to increased interest in research of these microorganisms. However, this has contributed to a lack of research in the isolation and characterization of methicillin-susceptible S. aureus strains (MSSA). In this study, the prevalence of S. aureus in pigs in the nursery and finishing stages were analyzed. The susceptibility profiles to antibiotics, tolerance to heavy metals, and biofilm production of the isolates were evaluated using phenotypic and genotypic techniques. A total of 1,250 colonies suggestive of Staphylococcus spp. were isolated from 128 pigs, of which 63.6% (n = 795) belonged to this microbial genus. Sixty-seven colonies isolated from 34 animals (26.5%) were confirmed as S. aureus (8.4%). No strains resistant to copper, zinc, or methicillin were detected; however, all strains presented a resistance profile to at least three different classes of antimicrobials and 21 produced biofilms. These data are of concern, as they indicate the need for increased surveillance in the use of antimicrobials as well as reinforce the importance of studies on MSSA strains.(AU)

A emergência de cepas de Staphylococcus aureus resistentes à meticilina associadas à pecuária (LA-MRSA) e o papel potencial dos suínos na evolução dessas cepas têm levado ao aumento do interesse na pesquisa desses microrganismos. No entanto, isso tem contribuído para a falta de estudos sobre o isolamento e a caracterização de cepas de S. aureus sensíveis à meticilina (MSSA). Neste estudo, foi analisada a prevalência de S. aureus em suínos nas fases de creche e terminação. Os perfis de suscetibilidade aos antibióticos, a tolerância a metais pesados e a produção de biofilme dos isolados foram avaliados por meio de técnicas fenotípicas e genotípicas. Um total de 1.250 colônias sugestivas de Staphylococcus spp. foi isolado de 128 suínos, das quais 63,6% (n = 795) pertenciam a esse gênero microbiano. Sessenta e sete colônias isoladas de 34 animais (26,5%) foram confirmadas como S. aureus (8,4%). Nenhuma cepa resistente ao cobre, ao zinco ou à meticilina foi detectada; entretanto, todas as cepas apresentaram perfil de resistência a pelo menos três classes diferentes de antimicrobianos e 21 produziam biofilme. Esses dados são preocupantes, pois indicam a necessidade de maior vigilância no uso de antimicrobianos, bem como reforçam a importância de estudos com cepas de MSSA.(AU)

An Outbreak of USA300 Methicillin-Resistant Staphylococcus aureus Among People With HIV in Japan.

BACKGROUND: USA300 produces Panton-Valentin leucocidin (PVL) and is known as a predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) strain in the United States, but it was extremely rare in Japan. We report here an outbreak of USA300 in people with HIV (PWH) in Tokyo, Japan. METHODS: We analyzed the cases of PVL-MRSA infection between 2010 and 2020 and screened for nasal colonization of PVL-MRSA in PWH who visited an HIV/AIDS referral hospital from December 2019 to March 2020. Whole-genome sequencing-based single nucleotide polymorphism (SNP) analysis was performed on these isolates. RESULTS: During the study period, a total of 21 PVL-MRSA infections in 14 patients were identified after 2014. The carriage prevalence was 4.3% (12/277) and PVL-MRSA carriers were more likely to have sexually transmitted infections (STIs) within a year compared with patients who had neither a history of PVL-MRSA infection nor colonization (33.3% [4/12] vs 10.1% [26/258]; P = .03). SNP analysis showed that all 26 isolates were ST8-SCCmecIVa-USA300. Twenty-four isolates were closely related (≤100 SNP differences) and had the nonsynonymous SNPs associated with carbohydrate metabolism and antimicrobial tolerance. CONCLUSIONS: An outbreak of USA300 has been occurring among PWH in Tokyo and a history of STI was a risk of colonization.

Kingella negevensis shares multiple putative virulence factors with Kingella kingae.

Kingella negevensis is a newly described gram-negative bacterium in the Neisseriaceae family and is closely related to Kingella kingae, an important cause of pediatric osteoarticular infections and other invasive diseases. Like K. kingae, K. negevensis can be isolated from the oropharynx of young children, although at a much lower rate. Due to the potential for misidentification as K. kingae, the burden of disease due to K. negevensis is currently unknown. Similarly, there is little known about virulence factors present in K. negevensis and how they compare to virulence factors in K. kingae. Using a variety of approaches, we show that K. negevensis produces many of the same putative virulence factors that are present in K. kingae, including a polysaccharide capsule, a secreted exopolysaccharide, a Knh-like trimeric autotransporter, and type IV pili, suggesting that K. negevensis may have significant pathogenic potential.