Transcriptome analysis of biofilm formation under aerobic and microaerobic conditions in clinical isolates of Campylobacter spp.

This study investigated the effect of cefepime at sub-minimum inhibitory concentrations (sub-MICs) on in vitro biofilm formation (BF) by clinical isolates of Pseudomonas aeruginosa. The effect of cefepime at sub-MIC levels (½–1/256 MIC) on in vitro BF by six clinical isolates of P. aeruginosa was phenotypically assessed following 24 and 48 h of challenge using the tissue culture plate (TCP) assay. Quantitative real-time polymeric chain reaction (qRT-PCR) was employed to observe the change in expression of three biofilm-related genes, namely, a protease-encoding gene (lasA), fimbrial protein-encoding gene (cupA1), and alginate-encoding gene (algC), in a weak biofilm-producing strain of P. aeruginosa following 24 and 48 h of challenge with sub-MICs of cefepime. The BF morphology in response to cefepime was imaged using scanning electron microscopy (SEM). The TCP assay showed strain-, time-, and concentration-dependent changes in in vitro BF in P. aeruginosa following challenge with sub-MICs of cefepime, with a profound increase in strains with inherently no or weak biofilm-producing ability. RT-PCR revealed time-dependent upregulation in the expression of the investigated genes following challenge with ½ and ¼ MIC levels, as confirmed by SEM. Cefepime at sub-MICs could upregulate the expression of BF-related genes and enhance BF by P. aeruginosa clinical isolates.

Download Full-text

Biofilm Formation by Campylobacter jejuni Is Increased under Aerobic Conditions

Applied and Environmental Microbiology ◽

10.1128/aem.01878-09 ◽

2010 ◽

Vol 76 (7) ◽

pp. 2122-2128 ◽

Cited By ~ 122

Author(s):

Mark Reuter ◽

Arthur Mallett ◽

Bruce M. Pearson ◽

Arnoud H. M. van Vliet

Keyword(s):

Campylobacter Jejuni ◽

Food Chain ◽

Biofilm Formation ◽

Planktonic Cells ◽

Aerobic Conditions ◽

Food Borne ◽

Passive Release ◽

Bacterial Gastroenteritis ◽

Microaerobic Conditions ◽

Developed World

ABSTRACT The microaerophilic human pathogen Campylobacter jejuni is the leading cause of food-borne bacterial gastroenteritis in the developed world. During transmission through the food chain and the environment, the organism must survive stressful environmental conditions, particularly high oxygen levels. Biofilm formation has been suggested to play a role in the environmental survival of this organism. In this work we show that C. jejuni NCTC 11168 biofilms developed more rapidly under environmental and food-chain-relevant aerobic conditions (20% O2) than under microaerobic conditions (5% O2, 10% CO2), although final levels of biofilms were comparable after 3 days. Staining of biofilms with Congo red gave results similar to those obtained with the commonly used crystal violet staining. The level of biofilm formation by nonmotile aflagellate strains was lower than that observed for the motile flagellated strain but nonetheless increased under aerobic conditions, suggesting the presence of flagellum-dependent and flagellum-independent mechanisms of biofilm formation in C. jejuni. Moreover, preformed biofilms shed high numbers of viable C. jejuni cells into the culture supernatant independently of the oxygen concentration, suggesting a continuous passive release of cells into the medium rather than a condition-specific active mechanism of dispersal. We conclude that under aerobic or stressful conditions, C. jejuni adapts to a biofilm lifestyle, allowing survival under detrimental conditions, and that such a biofilm can function as a reservoir of viable planktonic cells. The increased level of biofilm formation under aerobic conditions is likely to be an adaptation contributing to the zoonotic lifestyle of C. jejuni.

Download Full-text

Enhancement of pyocyanin production by subinhibitory concentration of royal jelly in Pseudomonas aeruginosa

F1000Research ◽

10.12688/f1000research.27915.3 ◽

2021 ◽

Vol 10 ◽

pp. 14

Author(s):

Dina Auliya Amly ◽

Puspita Hajardhini ◽

Alma Linggar Jonarta ◽

Heribertus Dedy Kusuma Yulianto ◽

Heni Susilowati

Keyword(s):

Pseudomonas Aeruginosa ◽

Bacterial Growth ◽

Biofilm Formation ◽

Royal Jelly ◽

Microtiter Plate ◽

Multidrug Resistant ◽

Clinical Isolates ◽

Antibiotic Tolerance ◽

Subinhibitory Concentration ◽

Pyocyanin Production

Background: Pseudomonas aeruginosa, a multidrug-resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may potentially overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth, pyocyanin production, and biofilm formation of P. aeruginosa. Methods: Pseudomonas aeruginosa ATCC 10145 and clinical isolates were cultured in a royal jelly-containing medium to test the antibacterial activity. Pyocyanin production was observed by measuring the absorbance at 690 nm after 36 h culture and determined using extinction coefficient 4310 M-1 cm-1. Static microtiter plate biofilm assay performed to detect the biofilm formation, followed by scanning electron microscopy. Results: Royal jelly effectively inhibited the viability of both strains from a concentration of 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC 10145, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Concentrations of 12.5% and 6.125% significantly induced biofilm formation of P. aeruginosa ATCC 10145, in line with the results of the SEM analysis. Conclusions: The royal jelly concentration of 25% or higher inhibits bacterial growth; however, the subinhibitory concentration increases pyocyanin production and biofilm formation in P. aeruginosa. It is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.

Download Full-text

Haem agglutination Activity and Biofilm Formation from Clinical Isolates of Enterococcus and Their Characterization in a Tertiary Care Centre in Eastern India

Indian Journal of Medical Microbiology ◽

10.1016/j.ijmmb.2021.08.119 ◽

2021 ◽

Vol 39 ◽

pp. S35

Author(s):

Priyanka Paul Biswas ◽

Sangeeta Dey ◽

Luna Adhikary ◽

Aninda Sen

Keyword(s):

Biofilm Formation ◽

Tertiary Care ◽

Clinical Isolates ◽

Care Centre ◽

Eastern India ◽

Tertiary Care Centre

Download Full-text

Molecular Investigation of Fibronectin-Binding Protein Genes and Capacity of Biofilm Production in Staphylococcus Aureus Isolated From Clinical Samples

10.21203/rs.3.rs-640880/v1 ◽

2021 ◽

Author(s):

Hossein Jafari Soghondicolaei ◽

Mohammad Ahanjan ◽

Mehrdad Gholami ◽

Bahman Mirzaei ◽

Hamid Reza Goli

Keyword(s):

Staphylococcus Aureus ◽

Biofilm Formation ◽

Colorimetric Assay ◽

Binding Protein ◽

Clinical Isolates ◽

Diffusion Method ◽

Clinical Samples ◽

Biofilm Production ◽

Fibronectin Binding Protein ◽

Fibronectin Binding

Abstract Biofilm production increases Staphylococcus aureus resistance to antibiotics and also host defense mechanisms. The current study aims to evaluate the biofilm formation by S. aureus and to determine the prevalence of fibronectin-binding protein genes, also its correlation with drug resistance. In this study, 100 clinical isolates of S. aureus were collected. The antibiotic susceptibility pattern of the isolates was evaluated by the disk agar diffusion method. The ability of biofilm formation in the studied isolates was also determined by microplate colorimetric assay. Then, all isolates were screened by polymerase chain reaction for the fnbA and fnbB genes. Out of 100 clinical isolates of S. aureus, the highest and lowest antibiotic resistance rates were against penicillin (94%) and vancomycin (6%). Thirty-two cases were found to be multi-drug resistant (MDR) among the all strains. The ability of biofilm production was observed in 89% of the isolates. The PCR results showed that the prevalence of fnbA and fnbB genes were 91% and 17%, respectively. Moreover, 100% and 21.8% of the MDR strains harbored the fnbA and fnbB genes respectively. The ability to form biofilm in MDR isolates of S. aureus is more than non-MDR isolates, especially fnbA positive ones. As the bacteria in the biofilm are difficult to kill by antibiotics, attention to the removal or control of the biofilm production seems to be necessary.

Download Full-text

Assessment of biofilm formation by Campylobacter spp. isolates mimicking poultry slaughterhouse conditions

Poultry Science ◽

10.1016/j.psj.2021.101586 ◽

2021 ◽

pp. 101586

Author(s):

P.M. Araújo ◽

E. Batista ◽

M.H. Fernandes ◽

M.J. Fernandes ◽

L.T. Gama ◽

...

Keyword(s):

Biofilm Formation ◽

Campylobacter Spp

Download Full-text

Evaluation of Antibiotic Resistance Pattern, Alginate and Biofilm Production in Clinical Isolates of Pseudomonas aeruginosa

Iranian Journal of Public Health ◽

10.18502/ijph.v50i2.5349 ◽

2021 ◽

Author(s):

Fateme DAVARZANI ◽

Navid SAIDI ◽

Saeed BESHARATI ◽

Horieh SADERI ◽

Iraj RASOOLI ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Bacterial Resistance ◽

Antimicrobial Agents ◽

Clinical Isolates ◽

Diffusion Method ◽

Clinical Samples ◽

Resistance Pattern ◽

Alginate Production ◽

Opportunistic Bacteria

Background: Pseudomonas aeruginosa is one of the most common opportunistic bacteria causing nosocomial infections, which has significant resistance to antimicrobial agents. This bacterium is a biofilm and alginate producer. Biofilm increases the bacterial resistance to antibiotics and the immune system. Therefore, the present study was conducted to investigate the biofilm formation, alginate production and antimicrobial resistance patterns in the clinical isolates of P. aeruginosa. Methods: One hundred isolates of P. aeruginosa were collected during the study period (from Dec 2017 to Jul 2018) from different clinical samples of the patients admitted to Milad and Pars Hospitals at Tehran, Iran. Isolates were identified and confirmed by phenotypic and genotypic methods. Antimicrobial susceptibility was specified by the disk diffusion method. Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively. Results: Sixteen isolates were resistant to all the 12 studied antibiotics. Moreover, 31 isolates were MultidrugResistant (MDR). The highest resistance rate was related to ofloxacin (36 isolates) and the least resistance was related to piperacillin-tazobactam (21 isolates). All the isolates could produce the biofilm and alginate. The number of isolates producing strong, medium and weak biofilms was equal to 34, 52, and 14, respectively. Alginate production was more than 400 μg/ml in 39 isolates, 250-400 μg/ml in 51 isolates and less than 250 μg/ml in 10 isolates. Conclusion: High prevalence of MDR, biofilm formation, and alginate production were observed among the clinical isolates of P. aeruginosa. The results also showed a significant relationship between the amount of alginate production and the level of biofilm formation.

Download Full-text