Moderate Biofilm Producers Research Articles

Biofilm production ability and associated characteristics of Streptococcus agalactiae isolates from companion animals and humans

ObjectiveWe evaluated biofilm production ability (BPA) of Streptococcus agalactiae isolates from companion animals/humans and clarified the relationship between BPA populations and other microbiological features. MethodsCompanion animal-/human-origin isolates were collected with host information. We measured BPA using crystal violet staining, via virulence-associated gene profiling (hylB-pavA-pilB-spb1-srtC1-brpA), capsular genotyping, multilocus sequence typing, and antimicrobial resistance (AMR) phenotyping/genotyping. Significant difference in BPA of isolates from different hosts was assessed. We analyzed the association between BPA populations and the virulence genotypes, capsular genotypes, sequence types/clonal complexes, and AMR phenotypes/genotypes. Inhibitory effect of berberine on BPA was evaluated. ResultsFive, twenty-six, and twenty-six isolates belonged to strong, moderate, and weak biofilm producers, whereas seventeen showed no biofilm production. We defined strong, moderate, or weak biofilm producers as the producer group (n = 57) to conduct a comparative analysis between the producer and non-producer populations. There was a significant correlation between the producer population and vaginal specimen. We found significant associations between the producer group and presence (57.9%) of pilB and between the non-producer population and presence (70.6%) of spb1. There was no association between the producer group and capsular genotypes, sequence types/clonal complexes, and AMR phenotypes/genotypes (except for a significant correlation between the producer group and AMR to minocycline). We confirmed inhibitory effect of berberine at sub-minimum inhibitory concentrations (MICs) against the type strain on BPA. ConclusionOur observations suggest that S. agalactiae harboring pilB is more capable of producing biofilms, with berberine inhibitory effect at sub-MICs on BPA.

Antibiotic Resistance Profile and Biofilm Production of Staphylococcus pseudintermedius Isolated from Dogs in Thailand

Staphylococcus pseudintermedius is a zoonotic pathogen that can cause life-threatening infections in animals and humans. The study of methicillin-resistant S. pseudintermedius (MRSP) and its ability to produce biofilms is important to select the most suitable treatment. The prevalence and characteristics of S. pseudintermedius isolated from dogs admitted at the Veterinary Teaching Hospital, Prince of Songkla University, Thailand were assessed. Results showed that 28.30% (15/53) of the isolates were MRSP. Amplification of the mecA gene was observed in 93.33% (14/15) MRSP. Methicillin-resistant strains revealed co-resistant patterns against other antibiotics, including chloramphenicol, clindamycin, tetracycline, clarithromycin, ciprofloxacin, and trimethoprim. In this study, all bacterial isolates produced biofilms, while 90.55% of S. pseudintermedius isolates were strong or moderate biofilm producers. Most (45–60%) of the resistant strains were strong biofilm producers, while the correlation between biofilm production and antibiotic resistance was not statistically significant. This is the first study in southern Thailand to investigate the drug-resistant profile of S. pseudintermedius and its ability to form biofilm. The results will contribute to a better understanding of the emergence and prevalence of antimicrobial resistance in S. pseudintermedius.

Antibiofilm activity of selected plant essential oils from the Lamiaceae family against Candida albicans clinical isolates.

The virulence of Candida albicans is conditioned by several virulence factors, one of which is the formation of biofilm which reduces the sensitivity of the yeast to conventional antimycotics. This study determines the antifungal and antibiofilm activity of five essential oils (EOs) of the Lamiaceae family: Salvia officinalis, Thymus vulgaris, Rosmarinus officinalis, Origanum vulgare, and Hyssopus officinalis. In the preliminary research, the antifungal effect of eachof the EOs was tested in the concentration range of 200-0.4 mg/mL on planktonic Candida albicans (C. albicans) cells. A total of 13 C. albicans clinical isolates and one reference strain were evaluated on biofilm formation. Nine isolates (69.2%) showed weak biofilm production and four strains (30.8%) were detected as moderate biofilm producers. The EOs of Thymus vulgaris and Origanum vulgare were seen as effective antifungal agents on planktonic cells with the MIC 0.4 mg/mL. The highest average MIC values were recorded in Salvia officinalis EO (24.0 and 14.8 mg/mL). All isolates were used to determine EOs efficacy on the inhibition of adherence phase and biofilm formation. The biofilm production of C. albicans after exposition by EOs was quantitatively examined by crystal violet dye. The most effective for adherence phase and biofilm formation were EOs of Origanum vulgare (0.1 mg/mL and 0.3 mg/mL) and Thymus vulgaris (0.1 mg/mL and 0.4 mg/mL). The obtained results show that EOs of Thymus vulgaris and Origanum vulgare are potential agents for antifungal treatment or prophylaxis by reducing the resistance of pathogen.

Relationship between antibiotic resistance, biofilm formation, genes coding virulence factors and source of origin of Pseudomonas aeruginosa clinical strains.

Pseudomonas aeruginosa is an opportunistic pathogen that causes difficult with treating infections, especially in the immunocompromised and patients with some underlying disease. The aim of the study is to assess the antibiotic resistance, biofilm formation, and the presence of genes encoding various virulence factors in clinical isolates of P. aeruginosa. Seventy-three clinical isolates of Pseudomonas aeruginosa were tested. Antimicrobial Susceptibility Testing (AST) and carbapenemases production was performed in accordance with the EUCAST guidelines. The ability to form biofilm was assessed by crystal violet assay. Genes encoding selected virulence factors were detected using standard polymerase chain reaction (PCR). Among the 73 clinical isolates of P. aeruginosa, 41.1% were resistant to imipenem, 61.6% to meropenem, 30.1% to ciprofloxacin and 15.1% to tobramycin. Over 20% of isolates were producers of MBL. Antibiotic resistance profiling revealed that 23.3% of strains were sensitive to all antibiotics, 60.3% were LDR phenotype, and 16.4% were MDR phenotype. The majority of strains (73.6%) were strong-biofilm producers, 17.0% were moderate and 9.4% were weak biofilm producers. PCR analysis showed the presence of lasB, aprE and prpL genes in most of the tested strains (93.1%, 87.7% and 74.0%, respectively). Among strong biofilm producers, 22.2% were MDR, 63.0% of strains represented LDR phenotype, and 14.8% were sensitive to all antibiotics. Moderate and weak biofilm producers were LDR and sensitive phenotypes only (respectively, 58.3% and 42.9 - LDR, 41.7 and 51.7% - sensitive). High frequency of MDR strains and their ability of biofilm formation and virulence factors may be a threat to effective therapy, and can increase morbidity and mortality of infected patients.

Detection of als1 and hwp1 genes involved in biofilm formation in Candida albicans isolated from catheter associated candiduria.

Background: Candida species are opportunistic fungal pathogens that can affect immune compromised patients and may cause life threatening infections. Biofilm formation is an important virulence factor that enables Candida species to invade the host tissues. This study aimed to assess the ability of Candida albicans to form biofilm in patients with catheter associated candiduria and to determine the presence of some genes involved in biofilm formation at the molecular level. Methods: This cross-sectional descriptive study was carried out from June 2019 to June 2020 on 93 catheterized patients admitted to different wards at SCUHs, Ismailia. Candida albicans strains were identified phenotypically by their growth on sabouraud dextrose agar, Gram staining, growth on hypertonic sabouraud broth, chlamydospore formation and germ tube formation test. Biofilm formation was detected by tissue culture plate method. Detection of the genes involved in biofilm formation was done by PCR. Results: Twenty eight Candida albicans strains wereisolated from 36 Candida species. 9 isolates (32.1%) were strong biofilm producers, 6 isolates (21.4%) were moderate biofilm producers and 13 isolates (46.4%) were weak or non-biofilm producers. ALS1 gene was detected in 13 isolates (46.4%), while HWP1 gene was detected in 16 isolates (57.1 %). Conclusion: This study documented the prevalence of candiduria in catheterized patients and found a statistically significant higher prevalence of the tested biofilm forming genes among biofilm forming isolates as compared to the weak or non-biofilm forming ones; but additional studies should be carried out as the management of catheter associated caniduria is still controversial.

Antimicrobial resistance and virulence characteristics in ERIC-PCR typed biofilm forming isolates of P. aeruginosa

Pseudomonas aeruginosa is a serious pathogen particularly in immunocompromised patients. In this work, 103 clinical isolates of P. aeruginosa were collected and classified into weak, moderate, and strong biofilm producers according to their biofilm forming abilities via tissue culture plate method. The antimicrobial resistance and the presence of different virulence genes were investigated via disc diffusion method and polymerase chain reaction respectively. Moreover, ERIC-PCR typing was performed to investigate the genetic diversity among the clinical isolates.No significant correlation was observed between biofilm formation and resistance to each antimicrobial agent. Similar observation was detected concerning the multidrug resistance and biofilm formation. Regarding virulence genes, algD gene was harbored by all isolates (100%). Only pelA and phzM were significantly prevalent in strong biofilm producers. Additionally, the mean virulence score was higher in strong biofilm producers (9.33) than moderate (8.62) and weak (7) biofilm producers. Moreover, there was a significant correlation between the overall virulence score of the isolates and its ability to form biofilm. ERIC-PCR genotyping revealed the presence of 99 different ERIC patterns based on 70% similarity, and the different ERIC patterns were categorized into 8 clusters. 100% similarity indicates the possibility of cross-colonization in P. aeruginosa infections.

Phenotypic and genotypic characterization of mcr-1-positive multidrug-resistant Escherichia coli ST93, ST117, ST156, ST10, and ST744 isolated from poultry in Poland

BackgroundA plasmid-mediated mechanism of bacterial resistance to polymyxin is a serious threat to public health worldwide. The present study aimed to determine the occurrence of plasmid-mediated colistin resistance genes and to conduct the molecular characterization of mcr-positive Escherichia coli strains isolated from Polish poultry.MethodsIn this study, 318 E. coli strains were characterized by the prevalence of mcr1–mcr5 genes, antimicrobial susceptibility testing by minimal inhibitory concentration method, the presence of antimicrobial resistance genes was screened by PCR, and the biofilm formation ability was tested using the crystal violet staining method. Genetic relatedness of mcr-1-positive E. coli strains was evaluated by multilocus sequence typing method.ResultsAmong the 318 E. coli isolates, 17 (5.35%) harbored the mcr-1 gene. High antimicrobial resistance rates were observed for ampicillin (100%), tetracycline (88.24%), and chloramphenicol (82.35%). All mcr-1-positive E. coli strains were multidrug-resistant, and as many as 88.24% of the isolates contained the blaTEM gene, tetracycline (tetA and tetB), and sulfonamide (sul1, sul2, and sul3) resistance genes. Additionally, 41.18% of multidrug-resistant, mcr-1-positive E. coli isolates were moderate biofilm producers, while the rest of the strains showed weak biofilm production. Nine different sequence types were identified, and the dominant ST was ST93 (29.41%), followed by ST117 (17.65%), ST156 (11.76%), ST 8979 (11.76%), ST744 (5.88%), and ST10 (5.88%). Moreover, the new ST was identified in this study.ConclusionsOur results showed a low occurrence of mcr-1-positive E. coli strains isolated from Polish poultry; however, all the isolated strains were resistant to multiple antimicrobial agents and were able to form biofilms at low or medium level.

Biofilm formation of Staphylococcus aureus from milk and expression of the adhesion genes ebpS and cna at different temperatures.

This study investigated the ability of Staphylococcus aureus isolates from milk to form biofilm, through detection of adhesion genes, investigating exopolysaccharide (EPS) production and biofilm formation on polystyrene (PS) and stainless steel (SS) surfaces, and by quantifying the expression of ebpS and cna genes under different temperatures and culture media. Among the 31 isolates, the adhesion genes ebpS and cna were found in 81% and 61% of the isolates, respectively. The screening tests for phenotype revealed that 58% of the isolates were EPS producers, and 45% showed the ability to produce biofilm on PS. Nine of the 31 isolates were selected to verify their ability to form biofilm on SS, of which 3 were non-biofilm producers, 3 were poor biofilm producers, and 3 were moderate biofilm producers. However, all nine isolates produced biofilm on SS, regardless of their phenotypic profile on PS. Reverse-transcriptase quantitative PCR (RT-qPCR) revealed no variation in the expression levels of ebpS and cna genes at different temperatures, except for isolate S24 at 10 °C, for both genes tested. Moreover, RT-qPCR assays revealed that the expression levels of the adhesion genes ebpS and cna are isolate- and temperature-dependent; however, they are independent of the phenotypic biofilm-formation profile.

Phenotypic and genotypic characteristics of Acinetobacter baumannii enrolled in the relationship among antibiotic resistance, biofilm formation and motility

Acinetobacter baumannii is an important pathogen in clinical. The factors of biofilm formation, antibiotic resistance and motility contribute great to A. baumannii in persisting in stressed environment, and further leads to nosocomial infections. 70 A. baumannii clinical isolates were investigated for their clinical characteristics of infection. Among the tested strains, 54 (77.1%) isolates were obtained from ICUs, with the frequency of multidrug-resistance (MDR) at 55.7%, and that of extensively drug-resistance (XDR) at 31.4%. 97.1% of the clinical isolates could form biofilms, in which 4.3% possessed weak biofilm formation ability, while 41.4% and 51.4% were moderate and strong biofilm producers, respectively. A strong correlation between antibiotic resistance and biofilm formation ability was found that all the resistant strains could form biofilms, with the majority in moderate and strong levels, but 2.9% sensitive isolates had no such ability. However, the sensitive strains that could produce biofilms showed stronger biofilm formation capacity in the early stage before 24 h compared to the resistant isolates, though they became weaker afterwards. 24 biofilm-related genes and two blaOXA genes were found in both biofilm-forming and non-biofilm-forming strains, but with higher prevalence in the strains that could produce biofilms. No correlation was detected between twitching motility with antibiotic susceptibility or biofilm formation. These results raised a viewpoint that examining timepoint is a key factor for determining the biofilm formation ability, and further highlighted the importance of the appropriate surveillance and control measures in preventing the emergence and transmission of MDR and XDR A. baumannii.

Characterization of biofilm formation in clinical urinary isolates of Staphylococcus aureus from five hospitals in Lagos State, Nigeria

Background: Biofilm formation by pathogens is of great clinical importance as it mediates persistence and resistance to antibiotics, hence posing difficulty in treatment and management of diseases. The aim of this study was to evaluate the biofilm forming potential of Staphylococcus aureus isolated from urine samples of females with urinary tract infection and to detect the presence of clumping factor (clfA) and intracellular adhesion (icaA) encoding genes.Methodology: A total of 50 S. aureus were obtained from urine samples of women in five hospitals in Lagos State, Nigeria. Isolates were confirmed by standard biochemical and novobiocin susceptibility tests. The isolates were screened for biofilm formation using three methods; Congo-red agar (CRA), tube, and tissue culture plate (TCP) methods. Detection of clfA and icaA genes was done by PCR.Results: The Congo red agar method showed that 39 (78%) of the isolates were biofilm producers while 11 (22%) were non-biofilm producers. However, the tube method indicated that 12 (24%) were strong biofilm producers, 26 (52%) were moderate biofilm producers, and 12 (24%) were non-biofilm producers. The standard TCP assay showed that strong biofilm producers (OD > 0.240) were 13 (26%), moderate biofilm producers were 22 (44%), and weak or non-biofilm producers (OD < 0.120) were 15 (30%). The tube method showed a good correlation with the TCP method for strong biofilm production. Ten (20%) isolates possessed clfA gene and 31 (62%)possessed icaA gene.Conclusion: The ability of S. aureus to form biofilm is a key risk factor that can increase morbidity and mortality from infections they cause. Hence, rapid and sensitive phenotypic methods can be used in screening for biofilm formation thereby providing data that can guide therapy and control of the pathogen.
 Keywords: Staphylococcus aureus, Biofilm, Clumping factor, Intracellular adhesion

EVALUATION OF EFFLUX PUMP ACTIVITY AND BIOFILM FORMATION IN MULTIDRUG RESISTANT KLEBSIELLA PNEUMONIAE ISOLATES IN TANTA, EGYPT

Nosocomial and community acquired infections that caused by multidrug-resistant (MDR) Klebsiella pneumoniae isolates are widespread recently resulting in high morbidity and mortality due to limited number of treatment options with effective antibiotics. The aim of this study is to evaluate the antibiotic resistance profile, biofilm formation and efflux pump activity of MDR K. pneumoniae isolates collected from different hospitals in Tanta, Egypt. A total of 70 K. pneumoniae isolates characterized by standard biochemical tests and confirmed by MALDI-TOF/MS were screened for antibiotic susceptibility, efflux pump activity and biofilm formation. Isolates displayed high resistance to penicillins, cephalosporins, trimethoprim-sulfamethoxazole and the majority of tested fluoro/-quinolones and decreased resistance to imipenem, amikacin, chloramphenicol, tigecycline and colistin. Out of 70 K. pneumoniae isolates, 2 isolates exhibited Pan Drug-Resistance (PDR) profile while 57 (81.4%) and 11 (15.7%) exhibited MDR and Extensively drug-resistance (XDR) profiles, respectively. Sixty-four (91.4%) isolates exhibited efflux pump activity while all tested isolates had the ability to form biofilm with varied degrees as 40 (57.1%), 26 (37.1%), and 4 (5.7%) isolates were strong, moderate and weak biofilm producers, respectively. Also, a strong relation between efflux pump activity and biofilm formation per isolate was detected. In conclusion, Multidrug resistance, biofilm formation and efflux pump capabilities in K. pneumoniae have serious public health implications in the management and control of infections caused by this bacterium. Therefore, a multifaceted approach and precise planning are recommended in controlling these infections

Anti-Pseudomonas aeruginosa Activity of Metal Schiff Base Complex and Probiotics Against Planktonic- and Biofilm-Growing Cells

Introduction: The biofilm formation by Pseudomonas aeruginosa seems to protect the bacteria from antibiotics since these entities are highly resistant to such antimicrobial agents. The aim of this study was to investigate the role of Lactobacillus salivarus, Lactobacillus plantarum supernatants and CuII Schiff base complex in eliminating planktonic cells and biofilm of P. aeruginosa. Methods: One hundred specimens of blood, urine, cerebrospinal fluid, respiratory samples, and wound swabs were collected from patients attending three hospitals in Mashhad. All specimens were identified by biochemical tests. The susceptibility of the isolates to the conventional antibiotics was assessed using disk diffusion method. The biofilm formation ability of P. aeruginosa isolates was evaluated by crystal violet assay and confirmed using PCR. The anti-planktonic and antibiofilm ability of L. salivarus, L. plantarum supernatants and CuII Schiff base complex was evaluated separately in P. aeruginosa isolates. Results: The highest and lowest resistance rates were detected in Cefazoline (95%) and cefepime (23%), respectively. The thickest biofilm was produced by 8% of P. aeruginosa isolates, 9% and 83% of the isolates were considered as moderate and weak biofilm producers, respectively. The rhlR and lasR genes were reported in 100% of the isolates, but the algD gene existed in 92% of them. Conclusion: Particularly, the CuII Schiff base complex could affect both planktonic and biofilm cells by the lowest concentration in comparison of probiotic supernatants. L. plantarum supernatant inhibited planktonic cells at a lower concentration than L. salivarius. Also, L. salivarius showed better antibiofilm activity than another probiotic in lower doses of supernatant. Unlike that, these compounds have not completely eliminated biofilm cells, but only reduced the biofilm formation. : Metal Schiff base complex and Lactobacillus supernatants is a potent antimicrobial agent against Pseudomonas aeruginosa biofilm cells.

Prevalence, antimicrobial resistance, and biofilm formation of Klebsiella pneumoniae isolated from human and cows

Klebsiella pneumoniae (K. pneumoniae) is an important multidrug-resistant (MDR) and biofilm producing pathogen that causes diverse infections in human and animals. This study aimed to evaluate the prevalence, antimicrobial resistance, and biofilm forming ability of K. pneumoniae isolates from diseased humans sputum and urine samples and mastitic cows milk samples in Zagazig city, Sharkia Governorate, Egypt. A total of 100 human and animal samples were collected and examined for the presence of Klebsiella species. The recovered isolates were identified by conventional bacteriological procedures and confirmed by the traditional PCR at the genus and species levels using gyrA, 16S-23S ITS and pehX genes, respectively. The confirmed K. pneumoniae isolates were subjected for testing their antimicrobial susceptibility and biofilm formation ability. The results revealed that 10 out of 50 human samples were positive for K. pneumoniae (20%); 28% (7/25) from sputum samples and 12% (3/25) from urine samples. Additionally, the prevalence rate of K. pneumoniae in milk samples from mastitic cows was 4% (2/50). PCR assays confirmed the 12 isolates as K. pneumoniae. The antimicrobial susceptibility results showed that K. pneumoniae isolates had high resistance rates to ampicillin and ampicillin/clavulanate (100% each) with multiple antibiotic resistance (MAR) index of 0.083, followed by azithromycin, cefepime, and trimethoprim/sulphamethoxazole (91.7% each). Meanwhile, these isolates revealed high sensitivity levels to chloramphenicol (83.3%) with MAR index of 0.014. Furthermore, 91.7% of K. pneumoniae isolates were able to produce the biofilm, where 8.3% was a non-biofilm producer. Out of 11 K. pneumoniae isolates, 6 (54.5%), 3 (27.3%) and 2 (18.2%) were moderate, strong and weak biofilm producers, respectively. The present study emphasized the high prevalence of MDR and biofilm producing K. pneumoniae isolates in human sputum and urine samples. Therefore, more attentions should be taken against antimicrobials usage and for providing new antibiofilm approaches against Klebsiella species biofilms.

Effect of antimicrobials on Stenotrophomonas maltophilia biofilm.

Aim: To evaluate the activity of five antimicrobials against young and mature Stenotrophomonas maltophilia biofilms. Materials &methods: Nineteen clinical strains from hemoculture of hemodialysis patients were tested for biofilm kinetics, MIC and minimum biofilm inhibitory concentration (MBIC) in young and mature biofilms. Results: All strains were moderate biofilm producers. MIC showed total susceptibility to levofloxacin and trimethoprim-sulfamethoxazole and partial resistance to ceftazidime (63.2%) and gentamicin (21%). Young and mature biofilms showed the lowest MBIC/MIC ratio for gentamicin, chloramphenicol and levofloxacin, respectively. The highest MBIC/MIC was for trimethoprim-sulfamethoxazole (young) and ceftazidime (mature). Conclusion: Gentamicin displayed surprising activity against S. maltophilia biofilms. Chloramphenicol was indicated as a good option against young S. maltophilia biofilms, and trimethoprim-sulfamethoxazole showed limited antibiofilm activity.

Molecular studies on Clostridium perfringens from broiler chicken farms in Egypt with special reference to biofilms and resistance to disinfectants

At the most cases, C. perfringens has the ability to form biofilms in order to persist in the environment as, the predominant structural state of bacteria in nature is biofilms which increase the bacterial tolerance to disinfection that can lead to economic and health concerns. Two hundred eighteen samples (88 liver samples and 130 intestinal samples) were collected from clinically affected chickens with necrotic enteritis and revealed the presence of C. perfringens with percentage of 94.6 % and 78.4% respectively with total percentage 86.5 %. Twenty suspected C. perfringens isolates were examined by PCR and the results revealed that all of the examined samples were identified as C. perfringens and all samples revealed bands of AppB gene at 109 bp, 17 of 20 samples gave iolD gene bands at 98 bp and 13 of 20 samples gave ripH gene bands at 105 bp. These isolates were used for antiobiotic susceptibility testing and results showed that all isolates were highly susceptible to imipenem. Also, Most of isolates were highly susceptible to Ampicillin and Amoxicillin but, all isolates were resistant to Sulphamethoxazole trimethoprim, Colistin, Tylosine and Lincomycin and also, all isolates showed multidrug resistance. And these isolates were screened for biofilm producing ability and results showed that all the twenty isolates were strong biofilm producers except three isolates which were moderate biofilm producers, Nine types of disinfectants commonly used on poultry farms were used to test their efficacy on C. perfringens biofilms and Sodium hypochlorite 0.027% was the most efficient disinfectant on C. perfringens biofilms.

A Study on Phenotypic Association between Biofilm and Drug Resistant Klebsiella Species Isolated from Urinary Tract Infections

Introduction: Urinary Tract Infections (UTI's) are considered to be one of the most prominent infections, worldwide. Klebsiella species are the commonest cause of community and hospital acquired UTIs. Biofilm production and hyper-mucous production are the important virulence factors among the pathogenic strains of Klebsiella species. Biofilm-associated and Hyper-Mucoviscosity (HMV) variants of Kiebsiella spp. ispotent enough to easily colonise the urinary tract, develop the invasiveness of infection and mainly contribute in higherresistance to most classes of antibiotics. Understanding the virulence factors associated with Multi Drug Resistant (MDR) Klebsiella spp. would aid in estimating the resistance related mortality. Aim: To identify and comparatively analyse the HMV, biofilm-producing capacity and drug resistance pattern of archived Klebsiella spp. isolates from UTI. Materials and Methods: This study was a cross-sectional, descriptive study. A retrospective analysis was performed during January 2020 to March 2020 on 207 archived Klebsiellaspp. isolates collected between December 2017 to January 2019. The presumptive identification of Klebsiella spp. was done using standard microbiological techniques. Antimicrobial susceptibility test was performed as per Clinical and Laboratory Standards Institute (CLSI) guidelines. Klebsiella spp. were tested for biofilm production using microtiter plate method and HMV phenotype by string test. Descriptive statistics and Student’s t-test were performed to analyse the data. Results: A total of 207 Klebsiella isolates were used in this study and majority (94.6%) of the isolates were identified as Klebsiella pneumoniae subsp. pneumoniae. Out of 207 isolates, 14 isolates (6.8%) were Extensively Drug Resistant (XDR); 141 isolates (68.1%) were MDR; 43 isolates (20.8%) were resistant to one or two class of antibiotics. Biofilm detection assay showed 97.1% (201/207) were strong biofilm producers and 2.9% (6/207) were moderate biofilm producers. String test for HMV detection showed only two isolates (1.0%) were positive HMV producers. Among the biofilm producers, majority of the Klebsiella isolates were found to be MDR. Conclusion: Resistance in Klebsiella spp. is an evolving problem. Majority of the drug resistant Klebsiella isolates used in present study were strong biofilm producers. This study emphasises on the sensible use of last resort drugs to cut down the evolution of resistant strains.

Http://www.plantarchives.org/SPECIAL%20ISSUE%2021-1/429%20(2636-2640).pdf

In the present study, Fifty random samples of each small-scale (plain yoghurt and kariesh cheese) were collected randomly from different dairy shops and markets in Zagazig city for isolation and identification of Escherichia coli which is considered a good indicator of faecal contamination and a major cause of food poisoning. Identification was done microscopically and biochemically by different biochemical tests (IMVIC).The incidence of E. coli in yoghurt and kariesh cheese samples were 36% and 50%, respectively. Also, the serological identification of E. coli isolates revealed that O26 is the most predominant serogroup by percentagesof27.77% and 28% in both yoghurt and kariesh cheese samples, respectively. Because of its rising resistance to antibiotics, E.coli represents a real threat to human health. Antimicrobial susceptibility testing (AST) was done by disc diffusion method against 10 antimicrobials and the results revealed that E. coli isolates were highly resistant to amoxicillin-clavulanate, ampicillin, Cefotaxime and Ceftazidime, and were highly sensitive to chloramphenicol, Ciprofloxacin and tetracycline. In addition, 83.72%of E. coli isolates showed multi drug resistance (MDR).Bacterial adhesion to food surfaces and the formation of biofilmisa source of food contamination that has an impact on food safety and industry. Micro titer plate assay was used for testing biofilm formation and revealed that 69.77% of E. coli isolates were non-biofilm producers, 9.30% were weak biofilm producers, 20.93%were moderate biofilm producers and none of isolates was strong biofilm producers. Virulence genes of E. coli isolates were identified and characterized by a multiplex PCR assay. The results showed that among the target genes, stx1was most frequently detected by a percentage of81.82%

The classification of Staphylococcus aureus strains by biofilm production differs depending on the method used

IntroductionStrains can be classified in terms of biofilm production from quantitative absorbance values collectively by dividing strains into tertile ranks or individually by calculating the optical density for the negative control. However, these methods have not been compared in a large sample of Staphylococcus aureus strains. Therefore, our objective was to analyze the agreement between both methods in terms of biomass production and metabolic activity of their biofilm. MethodsWe classified 233 S. aureus strains by biomass production and metabolic activity using the crystal violet and XTT assays, respectively. Strains were classified as low, moderate, or high biofilm producers according to tertile or optical density. ResultsWe found no agreement between both methods (p<0.001 and p=0.028, respectively). ConclusionsWe consider strains’ biofilm classification by optical density to be a more reliable method, as it depends on the individual absorbance of each strain.

Molecular typing, biofilm formation, and analysis of adhesion factors in Staphylococcus aureus strains isolated from urinary tract infections

Staphylococcus aureus is considered one of the principal bacteria challenges in public health today and is found particularly in patients with urinary tract infections. The data is still insufficient regarding biofilm-forming strains isolated from UTIs in Iran. In the present survey, 110 S. aureus strains were detected by antimicrobial susceptibility testing and biofilm formability. S. aureus isolates were also further investigated by carriage of biofilm and adhesion genes, and accessory gene regulator (agr) specificity groups using PCR and multiplex PCR. Out of 110 isolates tested, MRSA and MSSA accounted for 56.4% and 43.6%, respectively. Seventy-seven (70%) isolates were established as biofilm makers with complete dominant clfA, clfB genes and a markedly high prevalence of fnbA (80%), followed by fnbB (77.3%), sdrC (68.2%), icaA (62.7%), icaD (58.2%) eno (58.2%), sdrD (53.6%), ebps (38.2%), cna (25.5%), fib (20%), sdrE (17.3%), and bap (3.6%). A total of 4 agr types; type III (54.5%), II (20.9%), I (18.2%) and IV (6.4%) were detected in this study. The strong biofilm producers were assigned to particular agr type I (3.9%, 3/77), IV (1.3%, 1/77), and III (57.1%, 44/77), moderate biofilm producers to agr types I, II, and III, and weak biofilm producers to agr type II. Our findings illustrate corrections between biofilm formation and agr type III. We detected a high rate of MDR and biofilm formation in MRSA and MSSA strains isolated from UTI in varying degrees, which confirms the act of formation of biofilm in promoting antibiotic resistance.

Antifungal and Antibiofilm Activities of Selective Serotonin Reuptake Inhibitors Alone and in Combination with Fluconazole.

Candida spp. are clinically important pathogens that cause difficulties for treatment by biofilm formation. Considering antifungal resistance rates and the limitations in the discovery of new antifungals, the antifungal and antibiofilm effects of various drugs used for different therapeutic purposes are becoming more important. The goal of our study was to determine the antifungal and antibiofilm effects of the selective serotonin reuptake inhibitors (SSRIs), namely sertraline (SRT), paroxetine (PRX), and fluoxetine (FLX) alone and in combination with fluconazole (FLC) against Candida spp. Twenty Candida spp. strains isolated from clinical samples from Ege University Hospital were identified by the Dalmau method and matrix-assisted laser desorption ionization time of flight mass spectrometry. The minimum inhibitory concentrations (MICs) of the SSRIs and FLC were detected by broth microdilution method. Synergistic interactions between the SSRIs and FLC were investigated by checkerboard assay. The antibiofilm effects of the SSRIs were determined by spectrophotometric microplate method. Among the isolates, five different Candida spp. (C. albicans, C. glabrata, C. krusei, C. tropicalis, and C.parapsilosis) were identified. The MICs of the SSRIs ranged between 16-512 μg/mL. While SRT showed the highest antifungal effect, the antibiofilm efficacy of FLX was higher than that of the other agents. Moreover, FLX and PRX showed a synergistic effect with FLC in 13 and 19 isolates, respectively. Four isolates were strong biofilm producers while nine isolates were moderate biofilm producers. C. parapsilosis strains showed higher biofilm production than the other species. At MIC/2 concentration, FLX and SRT alone inhibited mature biofilms in six and five isolates, respectively, while PRX caused increases biofilm formation in seven isolates. This study revealed that MIC/2 concentrations of SSRIs could have antifungal and antibiofilm effects. SRT and FLX alone or in combination with antifungals may possibly have therapeutic potential for combating fungal infections.