Culture Plate Method Research Articles

<p>Comparative study of antimicrobial resistance and biofilm formation among Gram-positive uropathogens isolated from community-acquired urinary tract infections and catheter-associated urinary tract infections</p>

Background: Gram-positive cocci have emerged to be an important cause of urinary tract infection (UTI) both in community-acquired UTI (Com-UTI) and catheter-associated urinary tract infection (CA-UTI). The objective of this study was to investigate the frequency of Gram-positive cocci urinary tract infections, their susceptibility patterns to commonly used antimicrobial agents and the biofilm forming property with respect to catheter-associated UTI and community-acquired UTI.Methods: A total of 1,360 urine samples from indwelling catheter and 10,423 from mid-stream urine were obtained during a 6-month period and processed following standard microbiological guidelines. Biofilm formation was detected using congo red agar (CRA), tube method (TM) and tissue culture plate (TCP) method. Chi-square test and independent sample t-test were employed to calculate the significance. Statistical significance was set at P-value ≤0.05.Results: The infection rate was significantly higher in CA-UTI as compared to Com-UTI (25% vs 18%, p=0.0001). Among 2,216 organisms isolated, 471 were Gram-positive cocci; 401 were obtained from Com-UTI while 70 were from CA-UTI. Enterococcus faecalis was the most common organism isolated from Com-UTI, while Staphylococcus aureus was commonest among CA-UTI. Multi-drug resistance, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci were also significantly higher in CA-UTI as compared to Com-UTI. Biofilm-forming property was significantly higher in CA-UTI than Com-UTI. The sensitivity of congo red agar method and tube method was 79% and 81.9% respectively and specificity was 98.5% each. Antimicrobial resistance was significantly higher in biofilm-formers as compared to non-formers.Conclusion: Gram-positive bacteria are a significant cause of both CA-UTI and Com-UTI with Enterococcus faecalis and Staphylococcus aureus as common pathogen. Biofilm formation and multi-drug resistance is significantly higher in CA-UTI than Com-UTI. Routine surveillance of antimicrobial resistance and biofilm formation is necessary in all cases of UTI to ensure the proper management of patients.

Evaluation of Biofilm Formation and Frequency of Genes Encoding Curli Fiber, Colanic Acid Capsule and F1c Fimberia Among Uropathogenic Escherichia coli Isolates With Strong Cell Surface Hydrophobicity

Background: The uropathogenic Escherichia coli (UPEC) is an important bacterium that colonizes the bladder mucous membrane as biofilm and causes urinary tract infection (UTI). In addition, UPEC favors long-term persistence and leads to relapses in untreatable UTI. Further, bacterial hydrophobic interactions play a role in bacterial adherence to the surface and facilitate biofilm formation due to adhesion. Similarly, cell surface hydrophobicity (CSH), fimbriae, curli fiber, and colanic capsule allow UPEC isolates to initiate infections. Considering the above-mentioned explanation, this study evaluated the association between genes encoding curli fimbriae, colanic acid (CA) capsule, and f1c fimbriae with biofilm formation and CSH among UPEC isolates. Methods: To this end, 100 Escherichia coli strains were isolated from the urine samples of the patients and were diagnosed by biochemical tests. Furthermore, a tissue culture plate method was used to determine the capacity of biofilm formation, followed by conducting microbial adhesion to hydrocarbons method for CSH determination. Finally, the presence of csgA, csgD, rcsA, rcsC, and foc genes was determined by applying polymerase chain reaction. Results: Totally, 40, 22, and 28 isolates had strong, moderate, and weak biofilm formation capacity, respectively. Moreover, 42 and 38 isolates had strong and moderate CSH. Similarly, among the isolates with strong CSH, 32, 13, and 5 isolates had strong, moderate and weak biofilm formation capacity and the prevalence of csgA, csgD, rcsA, and foc genes was 33, 35, 35, 16, and 29, respectively. Based on the findings, no significant difference was observed between the frequency of csgA, csgD, rcsA, rcsC, and foc genes among the strong, moderate, and weak biofilm producers. Conclusions: In general, there is an association between CSH and the biofilm formation of UPEC isolates. This result showed the role of CSH as an effective factor on bacterial adhesion for the first stage of biofilm formation. However, differentiating the strains is not confirmed regarding their ability to form biofilms and their CSH and the presence of all studied genes.

Biofilm Formation by Uropathogens and Their Susceptibility Towards Antimicrobial Therapy

Introduction: Urinary tract infection (UTI) is the most common health care associated infection caused by various pathogenic bacteria. Biofilms are communities of bacteria that are held together by exopolymeric substances that protect against the antimicrobial therapy and other environmental assaults. The aim of this study was to estimate the prevalence of biofilm forming bacteria in Nepalese population and to study the emergence of antimicrobial resistance among biofilm producing bacteria in comparison to non-biofilm producing bacteria.
 Methods: A total of 785 clean-caught-mid-stream urine samples were collected. After isolation and identification of uropathogens, they were further processed for detection of biofilm formation by two methods (Congo Red Agar method and Tissue Culture Plate method) as well as for antibiotic sensitivity test.
 Results: Out of total collected samples, 12.74% were found to be associated with UTI, among them 67% were Escherichia coli, 10% were Klebsiella spp, 7% were Pseudomonas spp, 6% were Staphyloccous aureus, 4% were Enterobacter spp, 3% were Proteus spp, 2% were Citrobacter spp and remaining 1% was Staphylococcus saprophyticus. Among isolated organisms, the ratio of bioflim positive organism to bioflim negative organism was found to be 9:11. Nitrofurantoin, Tobramycin, Chloramphenicol, Amikacin and Imipenem were found to be significantly more sensitive in biofilm negative bacteria as compared to biofilm positive bacteria with p values of 0.000, 0.001, 0.000, 0.000 and 0.001.
 Conclusions: The prevalence rate of multidrug resistance in bacterial uropathogens was higher in biofilm producers as compared to non-biofilm producers. Biofilm forming characteristic of bacteria make them more resistant to antibiotics.

A Comparative Appraisal of Detection of Biofilm Production Caused by Uropathogenic Escherichia coli in Tropical Catheterized Patients by Three Different Methods

Introduction: Urinary tract infections (UTIs) are very common among Indian population which can be acute or chronic. However, untreated UTIs can lead to chronic condition which ultimately causes hospitalization. Objective: The present study aimed to study the comparison of three different methods of detection of biofilm production by uropathogens in tropical catheterized patients. Materials and Methods: The study included 500 tropical catheterized patients admitted in Civil Hospital, Ambala City. All the patients were interviewed as per a pre-defined protocol, and all the required medical informations were recorded in a pre-determined format for easy extraction as well as interpretations. Samples were collected for the tests to identify the microorganisms in the isolates and also to detect the biofilm product. Identification of microorganisms was performed by routine methods. Three different methods, namely tissue culture plate method (TCPM), tube adherence method (TAM), and modified Congo red agar (MCRA) method, were used to detection the biofilm production and compared. Results and Discussion: The results suggested that Escherichia coli is the most predominant uropathogen responsible for UTIs in the catheterized patients in the present studied patient population. Of these isolates, resistant E. coli cases were found to be most abundant and strong biofilm producer. Conclusion: TCPM was found to be significant method for the detection of biofilm production in this patient population, especially when the causative organism is resistant E. coli followed by TAM and MCRA method.

Antimicrofouling activities of marine macroalga Dictyota dichotoma from the Red Sea

Introduction. Marine organisms produce a variety of secondary metabolites mainly for achieving the defence against the competitors and predators. These compounds could be used as natural product antifoulants for the management of biofouling growth on marine structures. Objectives. To understand the antifouling defence strategies of marine macroalgae collected from the Red Sea. Methodology. The macroalga Dictyota dichotoma was collected from the Obhur Creek of Red Sea, Saudi Arabia and extracted using methanol. Surface and total extraction methods were performed and tested against a bacterial strain isolated from the microfouling assemblage. Results. The extracts obtained from the macroalgal samples have strong antibacterial and antibiofilm activities against the bacterial strain isolated from the marine microfouling assemblage. The total extracts showed strong bacterial growth inhibitory activities in culture plate method. In microtitre plate assay, surface extract showed strong biofilm inhibitory activity. GC-MS analysis indicated considerable variations in the metabolic profile of the surface and total extracts. Conclusion. This study revealed the importance of surface-associated compounds in antifouling defence mechanism of the marine macroalgae.

Antimicrofouling activities of marine macroalga Dictyota dichotoma from the Red Sea

Introduction. Marine organisms produce a variety of secondary metabolites mainly for achieving the defence against the competitors and predators. These compounds could be used as natural product antifoulants for the management of biofouling growth on marine structures. Objectives. To understand the antifouling defence strategies of marine macroalgae collected from the Red Sea. Methodology. The macroalga Dictyota dichotoma was collected from the Obhur Creek of Red Sea, Saudi Arabia and extracted using methanol. Surface and total extraction methods were performed and tested against a bacterial strain isolated from the microfouling assemblage. Results. The extracts obtained from the macroalgal samples have strong antibacterial and antibiofilm activities against the bacterial strain isolated from the marine microfouling assemblage. The total extracts showed strong bacterial growth inhibitory activities in culture plate method. In microtitre plate assay, surface extract showed strong biofilm inhibitory activity. GC-MS analysis indicated considerable variations in the metabolic profile of the surface and total extracts. Conclusion. This study revealed the importance of surface-associated compounds in antifouling defence mechanism of the marine macroalgae.

马衔山中国沙棘根瘤内共生细菌多样性研究

PDF HTML阅读 XML下载 导出引用 引用提醒 马衔山中国沙棘根瘤内共生细菌多样性研究 DOI: 10.5846/stxb201711082004 作者: 作者单位: 西北师范大学 生命科学学院,西北师范大学 生命科学学院,西北师范大学 生命科学学院,西北师范大学 生命科学学院,西北师范大学 生命科学学院,西北师范大学 生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31360005） Diversity of endophytic bacteria in root nodules of Hippophae rhamnoides in the Maxian Mountains Author: Affiliation: College of Life Science,Northwest Normal University,College of Life Science,Northwest Normal University,College of Life Science,Northwest Normal University,College of Life Science,Northwest Normal University,College of Life Science,Northwest Normal University,College of Life Science,Northwest Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采集甘肃省兰州市马衔山中国沙棘（Hippophae rhamnoidoes）根瘤样品，采用高通量测序和纯培养方法，分析中国沙棘根瘤内定殖的内共生细菌的组成、相对丰度和物种多样性，并比较两种方法研究结果的差异。在不同的微生物分类单元，高通量测序检测到中国沙棘根瘤内共生细菌24门50纲90目167科215属；而纯培养方法仅检测到3门5纲7目8科8属。进一步分析沙棘根瘤内共生细菌主要类群的相对丰度，发现高通量测序与纯培养方法的结果有明显差异，在科和属的分类单元上差异尤其显著。两种方法都表明中国沙棘根瘤内共生细菌具有丰富的多样性，但高通量测序能够较为全面的反映中国沙棘根瘤内共生细菌的群落组成，而纯培养方法仅能够分离到部分可培养的中国沙棘根瘤内共生细菌，在很大程度上极可能低估中国沙棘根瘤内共生细菌的物种组成并高估其丰度。 Abstract:Root nodules of Hippophae rhamnoides were collected in the Maxian Mountains. The plate culture method and high-throughput sequencing were used to study the diversity of endophytic bacteria in the root nodules of Hippophae rhamnoides. Microbial composition, abundance, and diversity of the nodule endophytic bacteria were analyzed. The differences in the results of the two techniques were compared. The results showed that 24 phyla, 50 classes, 90 orders, 167 families, and 215 genera of nodule endophytic bacteria were detected by high-throughput sequencing, and 3 phyla, 5 classes, 7 orders, 8 families, and 8 genera were obtained by plate culture. The relative abundances of the dominant nodule endophytic bacteria revealed that the differences between the results of the two techniques were greater at lower classification levels, especially at the family and genus levels, than at higher levels. Both plate culture and high-throughput sequencing showed an abundant diversity of nodule endophytic bacteria. High-throughput sequencing provides a more comprehensive and accurate picture of microbial community structure than the plate culture method does. Plate culture can only detect a few dominant taxa of nodule endophytic bacteria. The results of this study indicated that plate culture greatly underestimates microbial community composition and overestimate their abundance. 参考文献 相似文献 引证文献

Detection of biofilm among uropathogenic Escherichia coli and its correlation with antibiotic resistance pattern.

BACKGROUND:Escherichia coli accounts for 70%–95% of urinary tract infections (UTIs). UTI is a serious health problem with respect to antibiotic resistance and biofilms formation being the prime cause for the antibiotic resistance. Biofilm can restrict the diffusion of substances and binding of antimicrobials. In this context, the present study is aimed to perform in vitro detection of biofilm formation among E. coli strains isolated from urine and to correlate their susceptibility pattern with biofilm formation.MATERIALS AND METHODS:A total of 100 E. coli strains isolated from patients suffering from UTI were included in the study. The identification of E. coli was performed by colony morphology, Gram staining, and standard biochemical tests. The detection of biofilm was carried out by Congo Red Agar (CRA) method, tube method (TM), and tissue culture plate (TCP) method. Antimicrobial sensitivity testing was performed by Kirby–Bauer disc diffusion method on Muller–Hinton agar plate.RESULTS:Of the 100 E. coli strains, 49 (49%) and 51 (51%) were from catheterized and noncatheterized patients, respectively. Biofilm production was positive by CRA, TM, and TCP method were 49 (49%), 55 (55%), and 69 (69%), respectively. Biofilm producers showed maximum resistance to co-trimoxazole (73.9%), gentamicin (94.2%), and imipenem (11.6%) when compared to nonbiofilm producers. Significant association was seen between resistance to antibiotic and biofilm formation with a P = 0.01 (<0.05).CONCLUSION:A greater understanding of biofilm detection in E. coli will help in the development of newer and more effective treatment. The detection of biofilm formation and antibiotic susceptibility pattern helps in choosing the correct antibiotic therapy.

Tube method and Congo red agar versus tissue culture plate method for detection of biofilm production by uropathogens isolated from midstream urine: Which one could be better?

Background: Bacteria tend to live in assemblies called biofilms that aid bacterial virulence. Biofilms contribute to the development of antibiotic resistant urinary tract infection. Therefore, detection of biofilm production by urinary pathogens can assist the physicians to initiate the proper antimicrobial treatment.Methods: We conducted a prospective study that included patients with suspected urinary tract infection. Collected midstream urine samples were processed by standard microbiological techniques. Detection of biofilm production by the isolated uropathogens was conducted by tissue culture plate method (TCPM), tube method (TM) and Congo red agar (CRA).Results: A total of 43 (29.7%) isolated uropathogens showed positive biofilm formation by TCPM which was considered the gold standard for biofilm detection. When compared with the TCPM, TM truly identified 40 biofilm producers and 83 non-biofilm producers showing sensitivity and specificity of 93.0% and 81.4% respectively. The CRA truly identified 38 biofilm producers and 77 non-biofilm producers with sensitivity and specificity of 88.4% and 75.5% respectively.Conclusion: The TM was superior to CRA in biofilm detection and demonstrated better sensitivity and specificity results. Out of the investigated three phenotypic biofilm detection methods, the TCPM was the ideal method for detection of biofilm formation by uropathogens isolated from midstream urine samples. It can be used routinely in the microbiology laboratory with good specificity results and less subjectivity errors.

Exploration of bacterial contaminants in reservoirs of Palamuru by PCR-DGGE method: household water treatment

Abstract This study is principally aimed at the exploration of the bacterial contaminants that are prevalent in the drinking water of different reservoirs in Mahabubnagar, TS, India, along with cost-effective water treatment using palatable leaves of Mentha piperita. Water samples from three different reservoirs of Palamuru, namely, Ramanpadu reservoir (RPR), Koilsagar reservoir (KSR) and Jurala reservoir (JUR), were collected and bacteriological and chemical parameters were assessed. Colony forming units (CFU) were determined by plate culture method using different media. The bacterial diversity concomitant with the three different reservoirs was examined and compared using a molecular approach coalescing fingerprinting by denaturing gradient gel electrophoresis (DGGE). Overall, 37 16S rDNA sequences were obtained. The sequencing dominant bands validated that the major phylogenetic groups identified by DGGE belonged to Bacillus, Brevibacillus, Exiguobacterium, Gammaproteobacteria, Acinetobacter sp. and some uncultured or unidentified bacteria. At household level, incubation of potable water with pudina leaves decreased the bacterial contamination showing its anti-bacterial effect and proving it to be an easy method to impede bacterial contamination in potable water.

Investigation of Legionella contamination in soil

Objective To understand the contamination of Legionella in soil and the molecular type, sensitivity to antibiotics and intracellular growth ability of isolated strains. Methods A total of 123 soil samples from public places in Beijing were collected. Legionella in soil was detected by GVPC (Legionella selective medium) culture and quantitative real-time PCR detection. The intracellular growth ability of the Legionella isolates were tested by cell culture methods with mouse macrophage J774. The genotypes of the isolates were determined by pulsed-field gel electrophoresis. Antibiotic sensitivity detection of the isolates was conducted with E-test. Results Quantitative PCR assay detected Legionella in flower & bird market samples and reservoir samples in summer. The positive rates were 50.00% and 24.24% respectively. The plate culture method only detected Legionella in reservoir samples in summer. The positive rate was 6.06%. All the two Legionella strains isolated, TR1 and TR2, were L. pneumophila, and the serotypes were type 5 and type 8 respectively. All the two strains of L. pneumophila had high intracellular growth ability. PFGE typing showed two different band types. The drug sensitivity test showed that the two strains were sensitive to erythromycin, azithromycin, rifampicin, levofloxacin and moxifloxacin. TR1 showed resistance to cefuroxime, and TR2 was sensitive to cefuroxime. Conclusions Legionella pneumophila was detected in the soil of public places, and the isolates have higher intracellular growth ability, indicating the pathogenicity of the strains and suggesting the potential of causing legionellosis epidemic. Therefore, we should strengthen the monitoring of Legionella in public places.

Prevalence and associated risk factors of Strongyloides stercoralis infection in Lower Myanmar

BackgroundStrongyloidiasis is prevalent in Southeast Asian regions along with other soil-transmitted helminthiases, but only limited present-day data was available for Myanmar.MethodsA prevalence survey for Strongyloides stercoralis infection was conducted among villagers in rural areas of three townships located in the Lower Myanmar during 2014–2016 by agar plate culture method in combination with specific identification by molecular assays. Risk factors associated with S. stercoralis infection were assessed by analyzing questionnaires obtained from study participants.ResultsStrongyloides stercoralis was identified in 40 out of 703 participants (5.7% overall prevalence). The highest prevalence (14.4%) was observed in Htantabin, while other two communities (Thabaung and Thanlyin) had much lower prevalence (2.2 and 2.5%, respectively). Infection was relatively rare (1.2%) in younger generations under 20 years compared to older generations (9.5%). Even in Htantabin, none of the female residents under age 40 (n = 33) had infection. In adult Htantabin residents, those who answered that they do not wear shoes regularly had an elevated risk of infection (odds ratio = 2.50, 95% confidence interval = 1.03–6.08).ConclusionsThis study showed that there is still an on-going transmission of strongyloidiasis in Lower Myanmar. It is highly desirable that the soil should be free of fecal contamination by improving the management of fecal waste. Meanwhile, health education to promote shoe-wearing would be beneficial to reduce the risk of transmission, especially for those who have frequent and intense contact with soil.

Screening for Lipomyces strains with high ability to accumulate lipids from renewable resources.

The yeast Lipomyces accumulates triacylglycerols (TAGs) as intracellular fat globules, and these TAGs can be used as source materials for biodiesel production. In this study, we aimed to use this yeast to produce lipids from renewable resources. Using plate culture and micrograph methods, strains with a high lipid-accumulation ability were screened from 15,408 types of systems combining renewable resources, strains, and culture temperatures. The lipid-accumulation ability of the strains was estimated from the fat globule volume, which was calculated using a micrograph. The reliability of this method was examined, and strains with a high lipid-accumulation ability were identified for each renewable resource. Seventy-seven Lipomyces strains (7 deposit, 68 wild-type, 2 mutants) with a high lipid-accumulation ability were selected. A few strains possessed the ability to accumulate large amounts of TAGs from more than four different renewable resources. We found that strains with a high lipid-accumulation ability could efficiently convert consumed carbon sources into TAGs, which could be easily recovered from the fat globules of these strains through physical disruption.

Antibacterial and antibiofilm activity of cinnamaldehyde against carbapenem-resistant Acinetobacter baumannii in Egypt: In vitro study

Acinetobacter baumannii has emerged as a problematic nosocomial pathogen due to its antibiotic resistance as well as its ability to colonize and cause serious infection among patients. This study aimed to evaluate the ability of Acinetobacter baumannii to form biofilms as well as to investigate the antibacterial activity of cinnamaldehyde against carbapenem-resistant strains of A. baumannii. A total of 23 Acinetobacter baumannii clinical strains were screened for their ability to form a biofilm using tissue culture plate method. Cinnamaldehyde antibacterial ability was investigated on planktonic cells and its biofilm inhibition ability was tested. Scanning electron microscopy (SEM) was applied to confirm the antibiofilm effect of cinnamaldehyde. Biofilm formers (86.95 %) were categorized into strong (17.39%), moderate (52.17 %), weak (17.39 %). Cinnamaldehyde showed strong antimicrobial activity against planktonic cells of A. baumannii at low concentrations. The best antibiofilm activity was achieved at ½ MIC and ¼ MIC causing inhibition percentage ranging from 49.5% to 71.2% and 18.5% to 29.6% respectively. Cinnamaldehyde exerted strong antimicrobial and antibiofilm properties indicating their potential therapeutic value that can be used as an option for treating biofilm associated clinical problems caused by Acinetobacter baumannii.

Biofilm Formation of Staphylococcus aureus Isolated from Infected Wound

Background: Staphylococcus aureus has the ability to form biofilms, and causes significant mortality and morbidity in the patients with wounds. Our aim was to study the in vitro biofilm-forming ability of isolated S. aureus patients and methods: one hundred clinical isolates of S. aureus were isolated from 350 pus samples using standard microbiological techniques. Biofilm formation ability of these isolates was detected phenotypically by tissue culture plate (TCP) method and congo red agar (CRA) and genotypically by detection of ica ABCD genes by PCR. Results: The clinical isolates of S. aureus recovered from infected wounds exhibit a high degree of biofilm formation Biofilm formation was observed in (76 %), (74%) and (70%) isolates of S. aureus via TCP method CRA and genotypically, respectively. Conclusion: This study illustrated that PCR method can be adopted as most suitable an reproducible method for detection of biofilm. CRA is qualitative, simple, inexpensive and easily reproducible method and convenient as screening method. TCP is semiquantitative method and remains a precious tool for in vitro screening of different biomaterial for the adhesive properties. Regular surveillance of biofilm formation by S. aureus leads to the early treatment of the wound infection.

Antibiofilm activity of klebocin crude extract against some species of Enterobacteriaceae

Bacteriocins are antibacterial proteins created by bacteria and its effective against other strains of bacteria which are closely linked to the producing strains and a number of species from the same family. The aim of current study was to evaluate the activity of bacteriocin that extracted from clinical isolates of Klebsiella pneumonia against different species of enterobacteriaceae in both planktonic and biofilm state. The antibacterial activity of bacteriocins (klebocins) from Klebsiella pneumoniae isolates towards diverse pathogenic species from enterobacteriaceae (by well assay method) was demonstrated , however the antibiofilm activity against some species of enterobacteriaceae was studied also by Tissue culture plate method (TCP) in first and last stages of biofilm formation .The results revealed that klebocin with different concentrations was efficient against different pathogenic species by producing different inhibition zones. Results also showed that klebocins had a wide antibiofilm activity on some pathogenic species of Gram-negative bacteria .In addition to these finding it was observed that the antibiofilm activity of klebocin on premature biofilm of Klebsiella was higher than its effect towards other pathogenic species, while it was affected on mature biofilm of other bacterial species as well as Klebsiella.

Antibiotic resistance profiles of biofilm-forming bacteria associated with urine and urinary catheters in a tertiary hospital in Ile-Ife, Nigeria

Background: Microorganisms that infect humans differ in pathogenesis, virulence factors and antimicrobial resistance profiles. In natural settings, bacterial cells are most often found in close association with surfaces and interfaces, in the form of multicellular aggregates commonly called biofilms. Given their ubiquity and importance in the microbial world, it is hardly surprising that biofilms have attracted the attention of the scientific community. Biofilm formation on medical implant devices such as catheters is also a major problem that is closely tied to the adhesion and resistance-related abilities of the biofilm.Methodology: The ability of 216 bacterial isolates from mid-stream urine (100), catheter-stream urine (52) and catheter tips (64) to form biofilms was investigated using the tissue culture plate method, the tube and Congo red agar methods as well as their antibiotic resistance profiles using the agar disc diffusion method.Results: These revealed that Klebsiella spp. was the predominant bacterial genera accounting for 45.8% of the total isolates. A total of 50 isolates were biofilm-formers with 22% identified by the tissue culture plate method and 78% identified by the Congo red agar method. Klebsiella spp. had the highest ability to form biofilm while antibiotic resistance profiles showed all the biofilmformers to be multiply antibiotic resistant with least resistance to ofloxacin.Conclusion: It can therefore be concluded that some bacterial isolates associated with urinary tract infections have a propensity to form biofilm, thereby becoming multiply antibiotic resistant, and ofloxacin remains the antibiotic of choice in the treatment of such infections.

Detection of Biofilm Formation in Pseudomonas aeruginosa Isolates from Clinical Specimens

The ability of a microorganism to develop biofilm is considered as a marker of clinically relevant infection. Infections caused by P. aeruginosa are difficult to treat as the majority of isolates exhibit high level of innate resistance to many antibiotics and tendency to form biofilms. The study was undertaken to investigate biofilm-forming capabilities of P. aeruginosa isolated from clinical specimens by two main different methods tissue culture plate (TCP) method, and congo red agar (CRA) method. Further, to investigate the antimicrobial resistance profile among biofilm producing isolates. A total of 300 specimens were collected from patients. Ninety six isolates of P. aeruginosa were obtained from various clinical samples. We applied Vitek-2 automated system as a panel of antimicrobial agents. TCP method and CRA method assay was chosen to detect the biofilm formation. Out of the 96 isolates, the results by TCP method and CRA method were 84(87.5%) and 76(79.1%) isolates respectively. TCP method was the most sensitive method for detection of biofilm production. TCP method detected 78 as strong, 6 as moderate and 12 as weak or non- biofilm producers. By CRA method, 65,11and 20 of isolates were strong, moderate and weak or non-biofilm producers, respectively. The antibiotic resistance pattern of P. aeruginosa was found higher in biofilm producers than in biofilm non-producers.TCP method was considered as the gold standard and reliable method for detection of biofilm formation. We conclude that there has been a positive association between drug resistance and biofilm formation of P. aeruginosa.

Acinetobacter baumannii: Identification, Antibiotic Sensitivity and Biofilm Formation in Different Clinical Samples

Background: Acinetobacter baumannii is responsible for nosocomial infections which are related to biofilm formation of this pathogen. Biofilm formation helps the bacteria in surviving stressed environmental conditions and bacteria growing in biofilms are resistant to most of the commonly used antibiotics. Objectives: The objective of this study was to detect A. baumannii, to see antibiotic sensitivity and biofilm formation in different clinical samples.&#x0D; Methods: Total 108 Acinetobacter spp. were collected from different clinical samples which were identified by conventional microbiological procedures. Out of 108 Acinetobacter spp, 85 were identified as A. baumannii by polymerase chain reaction by detecting blaOXA-51 gene which is intrinsic to A. baumannii. Antibiotic sensitivity was detected by modified disc diffusion method and biofilm formation was detected by Tissue culture plate method.&#x0D; Results: Among 85 isolates, 45.9% A. baumannii were obtained from tracheal aspirate followed by blood (21.2%), wound swab (15.3%), urine (10.6%), pus (5.9%) and pleural fluid (1.1%). More than 80% 0f A. baumannii was resistant to cephalosporin, aminoglycosides, quinolone, carbapenem. By Tissue culture plate method, 78.8% of isolates showed biofilm formation. Biofilm formation in tracheal aspirate was 82.1%, in blood 72%, in wound swab 92%, in urine 44.4%, in pus 100% and in pleural fluid 100%.&#x0D; Conclusion: Detection rate of A. baumannii was more in tracheal aspirates. Biofilm producing A. Baumannii was resistant to most of the antibiotics.&#x0D; Bangladesh J Med Microbiol 2018; 12 (2): 4-9

Fennel oil: A promising antifungal agent against biofilm forming fluconazole resistant Candida albicans causing vulvovaginal candidiasis

AimTo screen the antimicrobial activities of some plant essential oils against clinical isolates of C. albicans causing vulvovaginal candidiasis (VVC) and to investigate the antifungal effect of the most active one against planktonic and sessile cells compared to fluconazole. MethodsScreening of biofilm production by C. albicans causing VVC was performed by tissue culture plate method. The antifungal susceptibility of fluconazole was performed by disk diffusion method. Antifungal activities of nine essential oils were screened against strong biofilm-producer, fluconazole-resistant or dose-dependently susceptible clinical isolates and Candida albicans ATCC 10,231 by well diffusion method. Determination of the minimum inhibitory concentration (MIC) of fennel essential oil and fluconazole against planktonic and sessile cells were performed by microdilution methods. Determination of the combined antimicrobial activity of fennel oil and fluconazole was evaluated by checkerboard microdilution assay. ResultsFrom 19 C. albicans strains, 10/19 showed strong ability to form biofilms. None of the tested clinical isolates was sensitive to fluconazole. Fennel oil had significantly higher antifungal activities against tested C. albicans compared with other tested oils (P = 0.000). The MICs of fennel oil for planktonic cells ranged from 0.78% to 6.25% with MIC50 of 3.12% and MIC90 of 6.25%, while concentrations ranging between 6.25% and 25% resulted in 50% biofilm reduction. Synergy or addition between fennel oil and fluconazole were detected against 7/11 strains, while no antagonism was detected. ConclusionFennel oil alone or in combination with fluconazole could provide a promising approach to the management of VVC caused by drug-resistant strains.