The correlation between the presence of quorum sensing, toxin-antitoxin system genes and MIC values with ability of biofilm formation in clinical isolates of Pseudomonas aeruginosa. - Related Documents




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577401.0000The correlation between the presence of quorum sensing, toxin-antitoxin system genes and MIC values with ability of biofilm formation in clinical isolates of Pseudomonas aeruginosa. INTRODUCTION: Pseudomonas aeruginosa is a Gram-negative bacterium that considered as important opportunistic human pathogen. One of the mechanisms that help bacteria to tolerate survival in adverse conditions and resistance to antibiotics is biofilm formation through quorum sensing (QS) signals and toxin-antitoxin (TA) systems. QS and TA are two systems that have important roles in biofilm formation. QS is a global regulatory mechanism that enable bacteria to communicate with each other by production of auto inducers (AI) molecules in population. Because of importance biofilm formation in P. aeruginosa infections, here, we studied frequency of QS and TA genes among clinical isolates of P. aeruginosa with ability of biofilm formation. MATERIALS AND METHODS: One hundred and forty clinical isolates of P. aeruginosa were collected from Tehran and Ilam hospitals. The isolates were identified by biochemical tests. Biofilm formation was evaluated by microplate method. After DNA extraction by boiling method, the frequency of QS genes (lasIR, rhlIR), and TA genes (mazEF, relBE, hipBA, ccdAB and mqsR) were analyzed by PCR. RESULTS: Our results showed that maximum resistance is related to aztreonam (72.85%) antibiotic. Most of isolates were able to produce biofilm (87.15%) and the majority of them formed strong biofilm (56.42%). PCR results showed that frequency of mazEF, relBE, hipBA, ccdAB, mqsR, lasIR and rhlIR genes were 85.71, 100, 1.42, 100, 57.14, 93.57 and 83.57 percent, respectively. CONCLUSION: Clinical isolates of P. aeruginosa had high ability to form biofilm, and QS and TA system genes among these isolates were very high (except hipBA genes). There are significaut correlation between biofilm for mation and present of QS and TA system genes.201425870745
565810.9995Molecular identification and biofilm formation of aerobic and anaerobic coinfection bacterial isolated from cystic fibrosis patients in southwest Iran from 2014 to 2022. BACKGROUND: Coinfections and resistant bacterial infections are more likely to occur in cystic fibrosis patients because their immune systems are weak. The purpose of this study was to identify by molecular means as well as the formation of biofilm of aerobic and anaerobic coinfection bacteria isolated from cystic fibrosis patients in southwest Iran from 2014 to 2022. METHODS: In this investigation, 130 clinical specimens were collected from 130 CF patients by universal primer. Biofilm formation was investigated using the microtiter plate method. Antibiotic resistance was measured using Vitec 2 device. In addition, identification of methicillin-resistant Staphylococcus aureus using genes mecA was performed. MAIN FINDINGS: In aerobic bacteria, Pseudomonas aeruginosa was detected in (32%) of samples. In anaerobic bacteria (16%) Prevotella spp. was the most frequently isolated anaerobe bacteria found in of the CF patients. In this study, 75% of the bacteria could form biofilms, while 23% were unable to biofilm formation. CONCLUSION: In conclusion, P. aeruginosa was found to be the most frequently isolated bacterium from patients with CF, and many of these bacteria could form biofilms. Additionally, the high prevalence of antibiotic resistance indicates the urgent need for increased attention to antibiotic preparation and patient screening concerning bacterial coinfections and the virulence and adhesion factors of these bacteria. Furthermore, the present study demonstrates that the coinfection of bacteria with high antibiotic resistance and a high capacity for biofilm formation can pose a life-threatening risk to CF patients, mainly due to their weakened immune systems.202337566205
578120.9995Antibiotic susceptibility of human-associated Staphylococcus aureus and its relation to agr typing, virulence genes, and biofilm formation. BACKGROUND AND OBJECTIVE: Carriage of virulence factors confers some evolutionary benefit to bacteria, which favors the resistant strains. We aimed to analyze whether antibiotic susceptibility of Staphylococcus aureus strains is affected by agr typing, biofilm formation ability, and virulence profiles. METHODS: A total of 123 S. aureus clinical isolates were subjected to antimicrobial susceptibility testing by disk diffusion method, biofilm formation by microtiter plate method, as well as polymerase chain reaction screening to identify virulence genes and the accessory gene regulator (agr) types I-IV. A P value < 0.05 was considered significant. RESULTS: The most prevalent virulence gene was staphyloxanthin crtN, followed by hemolysin genes, capsular cap8H, toxic shock toxin tst, and enterotoxin sea, respectively. Resistant isolates were more commonly found in the agr-negative group than in the agr-positive group. Isolates of agr type III were more virulent than agr I isolates. Strong biofilm producers showed more antibiotic susceptibility and carried more virulence genes than non-strong biofilm producers. Associations were found between the presence of virulence genes and susceptibility to antibiotics. Carriage of the virulence genes and agr was higher in the inpatients; while, resistance and strong biofilms were more prevalent in the outpatients. CONCLUSION: These findings indicated the presence of several virulence factors, biofilm production capacity, agr types and resistance to antibiotics in clinical S. aureus isolates. Considering the importance of S. aureus for human medicine, an understanding of virulence and resistance relationships would help to reduce the impact of S. aureus infections.202134210263
565930.9994Pseudomonas aeruginosa clinical isolates in Egypt: phenotypic, genotypic, and antibiofilm assessment of Pluronic F-127. BACKGROUND: Virulence factors play an important role in developing bacterial resistance leading to the increased severity of Pseudomonas aeruginosa infections. Several genes encoding for virulence factors is coordinated by the quorum sensing (QS) system. In the present study, the prevalence of virulence genes, particularly those involved in controlling biofilm formation, and their correlation with antibiotic resistance patterns was investigated. The ability of the pathogens to form biofilm and the impact of Pluronic F-127 as a potential biofilm inhibitor was assessed. RESULTS: A total of 118 P. aeruginosa clinical isolates were collected. The highest resistance rates were observed against ceftazidime (94%), while colistin was the most effective followed by polymyxin B with sensitivity rate 72% and 59%, respectively. Out of 118 isolates: 111 (94%) were biofilm producers, 24.6% of them were strong. The QS genes; lasR and rhlR, were detected in 85% and 89% of the isolates, respectively, toxA gene in 95% and ampC gene in 69% of the isolates. Pluronic F-127 was confirmed as a biofilm inhibitor in lowest concentration used 1.25 mg/ml which inhibits 78% of strong biofilm forming isolates and has better effect on detachment of established biofilm by 90% of biofilm forming isolates. CONCLUSION: The ability of bacteria to form biofilms contributes greatly to the development of antibiotic resistance, which leads to the occurrence of persistent and chronic bacterial illnesses. Many isolates exhibited moderate to strong biofilm forming ability, which showed a high resistance pattern. The results demonstrated that Pluronic F-127 has a promising level of biofilm inhibition and detachment in most isolates. It has a chance to serve as a substitute means for combating biofilm formation.202540281406
578540.9994Molecular characterization of resistance and biofilm genes of ESKAPE pathogens isolated from clinical samples: examination of the effect of boric acid on biofilm ability by cell culture method. Biofilm formation ranks first among the resistance and virulence factors crucial in forming ESKAPE pathogens. Once biofilm is formed, treating the infection with existing drugs is often futile. Therefore, in this study, resistant ESKAPE pathogens were isolated from intensive care units and sent to Atatürk University Yakutiye Research Hospital Microbiology Laboratory. This study investigated the biofilm formation and molecular characterization of resistant ESKAPE pathogens isolated from intensive care units. The bacteria's biofilm formation abilities, genes responsible for biofilm formation, and resistance characteristics were identified. The effect of boric acid (BA) on resistance and bacterial genes was evaluated by a bacterial infection cell culture model. The highest biofilm formation was observed in Escherichia coli, Enterococcus spp., and Pseudomonas aeruginosa Enterococcus spp. isolates showed the vanA gene in 14.6% and the vanC gene in 61% of the samples. Among Staphylococcus spp. isolates, 48.3% were MSSA, 34.5% were MRCNS, and 17.2% were MRSA. The KPC gene was detected in 50%, the OXA-48 gene in 40%, and the NDM gene in 15% of the isolates. In P. aeruginosa, the LasI and LasR quorum sensing system genes were found in 38.5% and 30.8% of the isolates, respectively. In E. coli isolates, OXA-48 was present in 35%, KPC in 31.7%, and TEM in 12.5%. BA demonstrated significant activity against ESKAPE pathogens. The combined antimicrobial activity of boron compounds showed a decrease in the expression level of the resistance gene. It will be promising for preventing hospital-associated infections.202540025436
578050.9994Antibiotic resistance, biofilm formation, and virulence genes of Streptococcus agalactiae serotypes of Indian origin. BACKGROUND: Group B Streptococcus (GBS) is a causative agent of various infections in newborns, immunocompromised (especially diabetic) non-pregnant adults, and pregnant women. Antibiotic resistance profiling can provide insights into the use of antibiotic prophylaxis against potential GBS infections. Virulence factors are responsible for host-bacteria interactions, pathogenesis, and biofilm development strategies. The aim of this study was to determine the biofilm formation capacity, presence of virulence genes, and antibiotic susceptibility patterns of clinical GBS isolates. RESULTS: The resistance rate was highest for penicillin (27%; n = 8 strains) among all the tested antibiotics, which indicates the emergence of penicillin resistance among GBS strains. The susceptibility rate was highest for ofloxacin (93%; n = 28), followed by azithromycin (90%; n = 27). Most GBS strains (70%; n = 21) were strong biofilm producers and the rest (30%; n = 9) were moderate biofilm producers. The most common virulence genes were cylE (97%), pavA (97%), cfb (93%), and lmb (90%). There was a negative association between having a strong biofilm formation phenotype and penicillin susceptibility, according to Spearman's rank correlation analysis. CONCLUSION: About a third of GBS strains exhibited penicillin resistance and there was a negative association between having a strong biofilm formation phenotype and penicillin susceptibility. Further, both the strong and moderate biofilm producers carried most of the virulence genes tested for, and the strong biofilm formation phenotype was not associated with the presence of any virulence genes.202337407919
234160.9993Effect of Salicylic Acid on the gene expression of FnbA and FnbB genes in Staphylococcus hominis. BACKGROUND: Staphylococcus hominis is an opportunistic pathogen that expresses surface proteins, which are adhesive proteins that play a major role in biofilm formation. Biofilm is a protective layer that provides S. hominis bacteria with greater antibiotic resistance and promotes its adherence to biomedical surfaces, facilitating its entry into the bloodstream. OBJECTIVE: This research aimed to investigate the activity of Salicylic Acid (SA) and its effect on the gene expression of biofilm genes (FnbA and FnbB genes). METHODS: A total of 150 blood specimens were collected from patients. The specimens were cultured in broth media of the BacT/ALERT® system and subcultured on blood and chocolate agar. Bacteria were detected using the VITEK2 system. FnbA and FnbB genes were detected using PCR. The broth microdilution method performed the minimum inhibitory concentration (MIC) of Salicylic acid (SA) on S. hominis isolates with both genes. Detection of the gene expression levels of FnbA and FnbB genes was assessed using Real-Time PCR(RT-PCR). RESULTS: The results showed that out of the 150 specimens collected, 35 were S. hominis. The detection of S. hominis bacteria was performed by PCR amplification of two genes FnbA and FnbB and showed 100% and 17.14% of isolates were positive for genes FnbA and FnbB, respectively. The expression of FnbA and FnbB genes was decreased in samples treated with SA compared with untreated ones. CONCLUSION: In conclusion, there is a significant impact of SA on the prevention of biofilm formation of S. hominis through the suppression of gene expression, specifically FnbA and FnbB. This could enhance susceptibility to antimicrobial treatments. However, more research is required to determine whether SA leads to the selection of resistant bacteria.202438875028
575970.9993The Relationship between Antibiotic Susceptibility and pH in the Case of Uropathogenic Bacteria. Urinary tract infections (UTIs) are common bacterial infections caused mainly by enteric bacteria. Numerous virulence factors assist bacteria in the colonization of the bladder. Bacterial efflux pumps also contribute to bacterial communication and to biofilm formation. In this study, the phenotypic and genetic antibiotic resistance of clinical UTI pathogens such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were determined by disk diffusion method and polymerase chain reaction (PCR). Following this, different classes of antibiotics were evaluated for their antibacterial activity at pH 5, 6, 7 and 8 by a microdilution method. Gentamicin (GEN) was the most potent antibacterial agent against E. coli strains. The effect of GEN on the relative expression of marR and sdiA genes was evaluated by quantitative PCR. The slightly acidic pH (pH 6) and GEN treatment induced the upregulation of marR antibiotic resistance and sdiA QS activator genes in both E. coli strains. Consequently, bacteria had become more susceptible to GEN. It can be concluded that antibiotic activity is pH dependent and so the artificial manipulation of urinary pH can contribute to a more effective therapy of multidrug resistant bacterial infections.202134943643
565580.9993Study of Disinfectant Resistance Genes in Ocular Isolates of Pseudomonas aeruginosa. BACKGROUND: The prevalence of disinfectant resistance in Pseudomonas aeruginosa is on the rise. P. aeruginosa is the most common bacteria isolated from cases of microbial keratitis. Many multi-purpose contact lens disinfectant solutions are available to decontaminate contact lenses before use and to help reduce the incidence of infections. However, with increasing disinfectant resistance, the effect of multi-purpose disinfectant solutions may diminish. The goal of this study was to examine genes associated with disinfectant resistance in ocular isolates of P. aeruginosa and understand the strain's susceptibility to different multipurpose disinfectant solutions. METHODS: Seven potential disinfectant resistance genes were used in BLASTn searches against the whole genomes of 13 eye isolates of P. aeruginosa. A microdilution broth method was used to examine susceptibility to four different multipurpose disinfectant solutions. RESULTS: All strains possessed the sugE2, sugE3 and emrE (qacE) genes. The sugE1 and qacEdelta1 genes were present in 6/13 isolates. No strains contained the qacF or qacG genes. All tested disinfectant solutions had the ability to kill all test strains at 100% concentration, with some strains being susceptible at 1:8 dilutions of the disinfecting solutions. However, the presence of disinfectant resistance genes was not associated with susceptibility to multi-purpose disinfectants. CONCLUSION: All four tested contact lens disinfectant preparations are effective against P. aeruginosa isolates regardless of the presence of disinfectant resistance genes.201830326554
578290.9993The Efficacy of Bacteriocins Against Biofilm-Producing Bacteria Causing Bovine Clinical Mastitis in Dairy Farms: A New Strategy. Using an alternative bio-product is one of the most promising ways to control bovine mastitis and avoid new intra-mammary infections. The aims of this study were to ascertain the prevalence of biofilm-forming bacteria responsible for causing clinical mastitis in dairy herds and to assess the effectiveness of bacteriocins, produced by Bacillus subtilis, in controlling the growth of these bacteria in the milk of animals. A total of 150 milk samples were collected from cows and buffalos suffering from mastitis and the etiological agents were isolated and identified by the VITEK-2-COMPACT-SYSTEM®. Additionally, the capability of the bacterial isolates to produce biofilms was determined. RT-PCR was used to detect enterotoxin-producing genes (sed and seb), resistance genes (mecA and blaZ), and biofilm-associated genes (icaA and fnbA) in the isolated bacteria. The susceptibility patterns of the bacterial isolates to bacteriocins were assessed using an agar well-diffusion assay. S. aureus was significantly more capable of producing biofilms than coagulase-negative Staphylococcus isolates. S. ubris was the strongest biofilm producer among the Streptococcus species. The sensitivity profiles of the Staphylococcus spp. (S. aureus and coagulase-negative Staphylococcus) and their biofilm producers to bacteriocins were significantly higher (100% and 90%, respectively) at the same concentration. Bacteriocins had a lethal effect on Staphylococci, Streptococci, and biofilm development at a dose of 250 µg/mL. In dairy farms, bacteriocins are a viable alternative treatment for the prevention and control of bovine clinical mastitis.202337256384
2351100.9993Association between biofilm production, adhesion genes and drugs resistance in different SCCmec types of methicillin resistant Staphylococcus aureus strains isolated from several major hospitals of Iran. OBJECTIVES: The ability of bacteria to produce biofilm and adhesion makes them more resistant to antibiotics. The current study aims to evaluate the biofilm formation by Staphylococcus aureus and to determine the prevalence of adhesion genes, also their correlation with drug resistance. MATERIALS AND METHODS: A total of 96 MRSA were collected from hospitals of Iran's western provinces during 2012 to 2013. The presence of ica A, B, C, D, clfA, cna, fnbA, mecA genes were determined by PCR technique. Biofilm formation was studied by microtiter plate assay, the clonal relations of the strains were examined by SCCmec and Spa typing. RESULTS: The results demonstrated that 96 % of isolates were biofilm producers. The distributions of biofilm formation between isolates were 4.2%, 54.2%, 35.4% as high, moderate and weak, respectivelly. The highest biofilm production was observed from blood culture isolates. All virulent genes icaA,B, C, D, clfA, cna, fnbA were observed in moderate and weak biofilm formation isolates. Among high biofilm formation isolates, icaB and cna genes were not seen. Statistical analysis showed that there was a significant correlation between ica, fnbA and the biofilm production, but there was not a significant correlation between the type of samples and drug resistance, spa type and SCCmec type with biofilm production (P>0.05). Frequency of All virulent genes in type III SCCmec was higher than other types. CONCLUSION: The majority of MRSA isolates were biofilm producers and blood isolates ranked as the great biofilm producer. In these isolates ica D and fnbA genes are correlated with biofilm production.201829796224
5783110.9993Molecular Investigation and Virulence Determination of Methicillin and Vancomycin Resistant Clinical Staphylococcus Aureus Isolates. Staphylococcus aureus is an opportunistic pathogen that provides conditions for host invasion due to various virulence factors and plays a role in causing various infections. The pathogenicity of these bacteria may vary depending on the host's susceptibility. This study investigates the sensitivity of S. aureus strains isolated from clinical samples to methicillin and vancomycin, and it evaluates the presence of resistance, virulence and toxin-producing genes, and their expression level in the methicillin-resistant S. aureus (MRSA), vancomycin-resistant S. aureus (VRSA), and vancomycin-intermediate S. aureus (VISA) isolates. A cross-sectional study was conducted, encompassing 502 S. aureus isolates obtained from diverse infections over the course of a year. The methicillin and vancomycin sensitivities of the isolates were ascertained by disk diffusion and microdilution broth methods, respectively. The presence of genes associated with resistance, adhesion, and toxin production was subsequently investigated through the implementation of multiplex polymerase chain reaction (PCR) methodology. The expression levels of virulence and resistance genes were detected in resistant and sensitive isolates using real-time quantitative PCR (qPCR). Among the 502 S. aureus isolates, 168 (33.6%) were identified as MRSA. Furthermore, a total of six isolates (1.2%) were identified as VRSA, and two isolates (0.4%) were identified as VISA. The distribution of virulence and resistance-related genes varied among the isolates. The results of the gene expression study demonstrated that the expression levels of the majority of the studied genes were significantly higher in resistant isolates (MRSA and VRSA) compared to sensitive isolates. It is imperative to acknowledge that VRSA and MRSA are regarded as grave hazards to human health. The present study underscores the necessity for enhanced sanitary measures to more effectively control this hospital pathogen, particularly in light of the presence and expression of genes encoding virulence factors in S. aureus isolates.202540980455
2786120.9993Frequency distribution of virulence factors and antibiotic resistance genes in uropathogenic Proteus species isolated from clinical samples. One of the most common causes of urinary tract infections (UTIs) is Proteus species. Because there is little information on the pathogenicity of Proteus species isolated from Iran, we assessed their virulence characteristics and antibiotic resistance in this study. In Shahrekord, Iran, 260 isolates of Proteus causing UTIs were identified from patients. Polymerase chain reaction for gene amplification was used to determine virulence features and antibiotic resistance gene distribution in uropathogenic Proteus spp. After biochemical and molecular analysis, 72 (27.69%) of the 260 collected samples were recognized as Proteus mirabilis, and 127 (48.84%) specimens were Pr. vulgaris in both male and female forms. A significant interaction effect between Pr. mirabilis and Pr. vulgaris infections and the sex of patients was seen in both the male and female groups. No statistically significant difference was observed between Pr. mirabilis infection and season in different year seasons. However, in different seasons of the year, a statistically significant difference was observed between infection with Pr. vulgaris in autumn and other seasons. There was a considerable difference between Pr. mirabilis and Pr. vulgaris infections at different ages in various age groups. As people aged, infections occurred more frequently. Fim,pap,kspMT, and set1 genes had the highest expression in both Pr. vulgaris and Pr. mirabilis. Also, the highest rate of antibiotic resistance of Pr. vulgaris and Pr. mirabilis is attributed to the high expression of aac(3)-IV,tet(A), and blaSHV genes. In conclusion, identifying these genes as the key controllers of Proteus virulence factors might help with better infection management.202336715324
5775130.9993Culture-independent detection of chlorhexidine resistance genes qacA/B and smr in bacterial DNA recovered from body sites treated with chlorhexidine-containing dressings. PURPOSE: Dressings containing chlorhexidine gluconate (CHG) are increasingly used in clinical environments for prevention of infection at central venous catheter insertion sites. Increased tolerance to this biocide in staphylococci is primarily associated with the presence of qacA/B and smr genes. METHODOLOGY: We used a culture-independent method to assess the prevalence of these genes in 78 DNA specimens recovered from the skin of 43 patients at catheter insertion sites in the arm that were covered with CHG dressings. RESULTS: Of the 78 DNA specimens analysed, 52 (67 %) possessed qacA/B and 14 (18 %) possessed smr; all samples positive for smr were also positive for qacA/B. These prevalence rates were not statistically greater than those observed in a subsample of specimens taken from non-CHG treated contralateral arms and non-CHG-dressing exposed arms. A statistically greater proportion of specimens with greater than 72 h exposure to CHG dressings were qac-positive (P=0.04), suggesting that the patients were contaminated with bacteria or DNA containing qacA/B during their hospital stay. The presence of qac genes was not positively associated with the presence of DNA specific for Staphylococcusepidermidis and Staphylococcusaureus in these specimens. CONCLUSION: Our results show that CHG genes are highly prevalent on hospital patients' skin, even in the absence of viable bacteria.201728463667
5765140.9993Expression of Pseudomonas aeruginosa Antibiotic Resistance Genes Varies Greatly during Infections in Cystic Fibrosis Patients. The lungs of individuals with cystic fibrosis (CF) become chronically infected with Pseudomonas aeruginosa that is difficult to eradicate by antibiotic treatment. Two key P. aeruginosa antibiotic resistance mechanisms are the AmpC β-lactamase that degrades β-lactam antibiotics and MexXYOprM, a three-protein efflux pump that expels aminoglycoside antibiotics from the bacterial cells. Levels of antibiotic resistance gene expression are likely to be a key factor in antibiotic resistance but have not been determined during infection. The aims of this research were to investigate the expression of the ampC and mexX genes during infection in patients with CF and in bacteria isolated from the same patients and grown under laboratory conditions. P. aeruginosa isolates from 36 CF patients were grown in laboratory culture and gene expression measured by reverse transcription-quantitative PCR (RT-qPCR). The expression of ampC varied over 20,000-fold and that of mexX over 2,000-fold between isolates. The median expression levels of both genes were increased by the presence of subinhibitory concentrations of antibiotics. To measure P. aeruginosa gene expression during infection, we carried out RT-qPCR using RNA extracted from fresh sputum samples obtained from 31 patients. The expression of ampC varied over 4,000-fold, while mexX expression varied over 100-fold, between patients. Despite these wide variations, median levels of expression of ampC in bacteria in sputum were similar to those in laboratory-grown bacteria. The expression of mexX was higher in sputum than in laboratory-grown bacteria. Overall, our data demonstrate that genes that contribute to antibiotic resistance can be highly expressed in patients, but there is extensive isolate-to-isolate and patient-to-patient variation.201830201819
5656150.9993Prevalence of silver resistance in bacteria isolated from diabetic foot ulcers and efficacy of silver-containing wound dressings. Silver dressings are used to manage wounds at risk of infection or locally infected. This in vitro study was conducted to assess the prevalence of silver resistance genes in 112 bacterial isolates obtained from the diabetic foot ulcers of patients attending the Diabetic Foot Clinic at Tameside General Hospital, UK. Using polymerase chain reaction to screen for three silver-resistance transcriptional units--silE, silS and silP--two silver-resistant bacteria were identified; both are strains of Enterobacter cloacae, an organism rarely implicated as a primary pathogen in chronic wounds. No recognized wound pathogens (Staphylococcus aureus-24 isolates and Pseudomonas aeruginosa-nine isolates) were found to contain silver-resistant genes. Analysis of the efficacy of silver-containing dressings on the silver-resistant strains of Enterobacter cloacae using confocal laser microscopy showed that, despite evidence of genetic resistance to silver, all strains were killed following a maximum of 48 hours of exposure to the dressings. Results suggest that presence of silver resistance genes is rare and that genetic resistance does not necessarily translate to phenotypic resistance to silver. While silver resistance in wound care should be monitored, the threat of widespread resistance is low and silver-containing dressings remain an extremely important tool in managing wound infection.200818382046
5800160.9993Observation and analysis of the efficacy of dexamethasone in combination with anti-infectious treatment on the pediatric refractory purulent meningitis. To analyze the pathogenic bacteria, feature of drug resistance and the efficacy of dexamethasone as the auxiliary medication in pediatric refractory purulent meningitis (PM). The 190 refractory PM child patients were selected for the culture of pathogenic bacteria and analysis of drug resistance. In total, 190 pathogenic bacteria were detected, consisting of gram-positive bacteria (77.37%). Of the gram-positive bacteria, the resistance rate of patients with staphylococcus epidermidis, streptococcus pneumoniae or Staphylococcus haemolyticus to levofloxacin was 100%, while in gram-negative bacteria, the resistance rate of patients with klebsiella pneumoniae to gentamycin was 100%. In the observation group, patients had a higher effectiveness rate. Besides, patients in the observation group recovered rapidly from the fever and anomalies in cerebral spine fluid and peripheral white blood cells, and the inflammation was greatly improved. However, difference in the incidence rates of adverse reactions of patients between two groups showed no statistical significance. Pediatric refractory PM involves the pathogenic bacteria, mainly including staphylococcus epidermidis and streptococcus pneumoniae, showing a high resistance to levofloxacin, while the auxiliary medication of dexamethasone can improve the efficacy, and inhibit the inflammation.202032173647
2479170.9993Down-regulatory effects of green coffee extract on las I and las R virulence-associated genes in Pseudomonas aeruginosa. BACKGROUND: Antibiotic resistant strains of Pseudomonas aeruginosa are the cause of Gram negative nosocomial infections especially among the immunosuppressed patients. The bacteria contains las I and las R genes that play very important roles in the pathogenesis and mechanisms of aggression. These genes can be influenced by the quorum sensing (QS) system and such mechanism is becoming clinically important worldwide. This study aimed to investigate the preventive effects of green coffee extract (GCE) on the expression of pathogenesis-related genes, las I and las R in P. aeruginosa. METHODS: A total of fifty four P. aeruginosa strains were isolated out of 100 clinical samples collected from the infectious wards in different hospitals (Tehran province) using conventional microscopic and biochemical methods. Susceptibility of the isolates to different antibiotics, GCE and chlorogenic acid were elucidated. Multiplex polymerase chain reaction (PCR) and real-time PCR were performed to detect and quantify the expression levels of las I and las R genes. The presence of chlorogenic acid in GCE was confirmed by HPLC. RESULTS: Antibiotic susceptibility tests revealed multidrug resistance among the clinical isolates of those 40 strains were resistant to ciprofloxacin (74.07%), 43 to ceftazidime (79.26%), 29 to amikacin (53.7%), 42 to ampicillin (77.77%), 17 to colistin (31.48%), 40 to gentamicin (74.77%), and 50 to piperacillin (92.59%). PCR outcomes exhibited that the frequency of las I and las R genes were 100% in resistant and sensitive strains isolated from clinical and standard strains of P. aeruginosa (ATCC 15449). Real-time PCR analyses revealed that GCE significantly prevented the expression of las I and las R genes in P. aeruginosa. GCE at concentration level as low as 2.5 mg/mL could prevent the expression of lasI and lasR genes in P. aeruginosa clinical isolates. CONCLUSION: The presence and expression levels of las I and las R genes in P. aeruginosa isolates were investigated when the bacteria was exposed to GCE. Our results tend to suggest that genes involved in pathogenesis of:Pseudomonas aeruginosa are down regulated by quorum sensing effect of chlorogenic acid and therefore GCE could be useful as an adjuvant in combating multidrug resistance strains of Pseudomonas aeruginosa.201931187452
5787180.9993Investigation of the association of virulence genes and biofilm production with infection and bacterial colonization processes in multidrug-resistant Acinetobacter spp. The aim of this study was to evaluate the phenotypic and molecular patterns of biofilm formation in infection and colonization isolates of Acinetobacter spp. from patients who were admitted in a public hospital of Recife-PE-Brazil in 2018-2019. For the biofilm phenotypic analysis, Acinetobacter spp. isolates were evaluated by the crystal violet staining method; the search of virulence genes (bap, ompA, epsA, csuE and bfmS) was performed by PCR; and the ERIC-PCR was performed for molecular typing. Amongst the 38 Acinetobacter spp. isolates, 20 were isolated from infections and 18 from colonization. The resistance profile pointed that 86.85% (33/38) of the isolates were multidrug-resistant, being three infection isolates, and two colonization isolates resistant to polymyxin B. All the isolates were able to produce biofilm and they had at least one of the investigated virulence genes on their molecular profile, but the bap gene was found in 100% of them. No clones were detected by ERIC-PCR. There was no correlation between biofilm formation and the resistance profile of the bacteria, neither to the molecular profile of the virulence genes. Thus, the ability of Acinetobacter spp. to form biofilm is probably related to the high frequency of virulence genes.202134550209
5657190.9993Biofilm and Antibiotic Resistance Study of Bacteria Involved in Nosocomial Infections. Nosocomial infections are increasingly problematic due to growing bacterial resistance. Biofilms play a key role in the persistence of these infections, leading to treatment failures and poor patient outcomes. Addressing antibiotic resistance within biofilms is especially critical in hospitals, making it essential to develop new strategies to manage biofilm-related infections and curb bacterial resistance. The study, conducted at the regional hospital center in Agadir, Morocco, analyzed 75 bacteria (37 antibiotic-sensitive and 38 resistant). Seven bacteria were isolated from catheters, and others from preserved samples. Biofilm formation was assessed using the tissue culture plate (TCP) method, involving strain recovery; culture on cystine, lactose, electrolyte-deficient (CLED) medium; microplate inoculation; staining with crystal violet; and optical density (OD) measurement. The results showed that 77.33% of the bacteria formed biofilms. All catheter-isolated bacteria showed biofilm formation. Strong biofilm production was observed in 66.67% of Acinetobacter baumannii and in most Pseudomonas aeruginosa strains. Enterobacteriaceae also demonstrated significant biofilm formation. Notably, 70% of carbapenem-resistant bacteria showed strong biofilm production. Most nosocomial bacteria form biofilms, with a higher prevalence in antibiotic-resistant strains. Sensitive bacteria also form biofilms but less frequently. Bacterial conjugation may facilitate the acquisition of carbapenem resistance within biofilms.202539926624