Biofilm-producing Isolates Research Articles

Exploring Drug Resistance: Microbial Profiles, Antibiotic Sensitivity, and Biofilm Development in Orthopedic Implant Infections.

Background With the advent of and rise in antibiotic resistance globally, especially in postoperative patients, studying the antibiogram and associated factors is the need of the hour. The present study was undertaken to document the microbiological profile in postoperative orthopedic patients with the infected implant in situ and to observe the antibiotic susceptibility patterns of isolated organisms in such infections. Methods This study was conducted in the Department of Microbiology of a tertiary care hospital for six months after obtaining institutional ethical approval. A total of 236 samples from patients with orthopedic implant infections were received during the study period, out of which 53 samples with positive culture isolate were further analyzed for microbiological profile including biofilm production. All observations and demographics were recorded and analyzed using SPSS software version 21.0(IBM Corp., Armonk, NY, USA) and represented in the form of graphs, data, and tables. Results and conclusion The study showed a culture positivity rate of 53 (23%) out of 236 samples, in which gram-negative isolates 36 (68%)were more than gram-positive isolates 17 (32%). The most common isolate was staphylococcus aureus 17 (32%) of which the majority were MRSA 13 (76%), followed by Escherichia coli 9 (17%) and Klebsiella pneumoniae 9 (17%). Out of the 53 isolates, 20 were biofilm producers. Biofilm-producing isolates were more resistant to tested routine antibiotics compared to non-biofilm. This study could represent the initial interdisciplinary effort in an ongoing process to better understand and manage orthopedic implant infections at the hospital, specifically focusing on infections related to orthopedic devices.

Antimicrobial Efficacy of Quercetin against Biofilm Production by <i>Staphylococcus Aureus</i>

Background: The bad administration of antibiotics represents a worldwide health issue as it leads to the emergence of multidrug-resistant microbes including Staphylococcus aureus, which represents a significant challenge for public health since it increases its ability to cause potentially fatal infections. Objective: This study aims to reduce the bacterium’s ability to form biofilms and antibiotic resistance. Methods: Thirty Staphylococcus aureus isolates were isolated from different clinical samples in Baghdad city and their ability to form biofilm was tested using the Microtiter Plate method. Out of 30 isolates, eight strong biofilm producer isolates were further investigated for their antimicrobial activity and biofilm formation with the impact of quercetin. Results: The results showed the ability of quercetin to inhibit bacteria and had an antibiofilm activity that was determined through investigation of the minimal inhibitory concentration by taking different concentrations. The anti-biofilm activity of quercetin was determined for the eight isolates and the results showed that biofilm formation was reduced by 100% using quercetin at a concentration of 3.1 mg/ml. Conclusions: Quercetin represents a suitable alternative to synthetic antimicrobials with the increased rate of drug-resistant bacteria among clinical samples with highly effective ability as anti-biofilm formation among strong biofilm producers of S. aureus.

Biofilm formation, agr typing and antibiotic resistance pattern in methicillin-resistant Staphylococcus aureus isolated from hospital environments.

Biofilm development significantly enhances the virulence of methicillin-resistant Staphylococcus aureus (MRSA), leading to severe infections and decreased susceptibility to antibiotics, especially in strains associated with hospital environments. This study examined the occurrence of MRSA, their ability to form biofilms, agr typing, and the antibiotic resistance profiles of biofilm-forming MRSA strains isolated from environmental surfaces at Mymensingh Medical College Hospital (MMCH). From 120 swab samples, 86 (71.67%) tested positive for S. aureus. MRSA was identified in 86 isolates using the disk diffusion technique, and by polymerase chain reaction (PCR), 56 (65.1%) isolates were confirmed to carry the mecA gene. The Crystal Violet Microtiter Plate (CVMP) test revealed that 80.35% (45 isolates) were biofilm-forming and 19.6% (11 isolates) were non-biofilm-forming. Out of 45 biofilm producer isolates 37.5% and 42.9% isolates exhibited strong and intermediate biofilm-forming characteristics, respectively. Molecular analysis revealed that 17.78% of MRSA isolates carried at least one gene related to biofilm formation, specifically icaA, icaB, and icaD genes were discovered in 13.33%, 8.89%, 6.67% of the MRSA isolates, respectively. In agr typing, the most prevalent group was agr I (71.11%), followed by group III (17.78%) and group II (11.11%). Group IV was not detected. The distribution of agr gene groups showed a significant difference among biofilm-forming isolates (p < 0.05). In agr group I, 18.75% of isolates carried the icaA gene, 12.5% carried the icaB gene, and 9.37% carried the icaD gene. Biofilm-forming genes were not detected in any of the isolates from agr groups II or III. There are no statistically significant differences between agr groups and the presence of these genes (p > 0.05). Antibiotic resistance varied significantly among agr groups, with agr group I displaying the highest resistance, agr group II, and agr group III exhibiting the least resistance (p < 0.05). Seventy-three (73.3%) of the isolates were multi-drug resistant, with agr group I displaying nineteen MDR patterns. The occurrence of MRSA in hospital environments and their capacity to form biofilm raises concerns for public health. These findings support the importance of further research focused on agr quorum sensing systems as a basis for developing novel antibacterial agents.

Unlocking the potential of biofilm-forming plant growth-promoting rhizobacteria for growth and yield enhancement in wheat (Triticum aestivum L.)

Plant growth-promoting rhizobacteria (PGPR) boost crop yields and reduce environmental pressures through biofilm formation in natural climates. Recently, biofilm-based root colonization by these microorganisms has emerged as a promising strategy for agricultural enhancement. The current work aims to characterize biofilm-forming rhizobacteria for wheat growth and yield enhancement. For this, native rhizobacteria were isolated from the wheat rhizosphere and ten isolates were characterized for plant growth promoting traits and biofilm production under axenic conditions. Among these ten isolates, five were identified as potential biofilm-producing PGPR based on in vitro assays for plant growth-promoting traits. These were further evaluated under controlled and field conditions for their impact on wheat growth and yield attributes. Surface-enhanced Raman spectroscopy analysis further indicated that the biochemical composition of the biofilm produced by the selected bacterial strains includes proteins, carbohydrates, lipids, amino acids, and nucleic acids (DNA/RNA). Inoculated plants in growth chamber resulted in larger roots, shoots, and increase in fresh biomass than controls. Similarly, significant increases in plant height (13.3, 16.7%), grain yield (29.6, 17.5%), number of tillers (18.7, 34.8%), nitrogen content (58.8, 48.1%), and phosphorus content (63.0, 51.0%) in grains were observed in both pot and field trials, respectively. The two most promising biofilm-producing isolates were identified through 16 s rRNA partial gene sequencing as Brucella sp. (BF10), Lysinibacillus macroides (BF15). Moreover, leaf pigmentation and relative water contents were significantly increased in all treated plants. Taken together, our results revealed that biofilm forming PGPR can boost crop productivity by enhancing growth and physiological responses and thus aid in sustainable agriculture.

Virulence Determinants of Buffalo Mastitis Originated Streptococcus agalactiae Isolates

Streptococci as a cause of mastitis have become the major concern to the dairy industry worldwide due to huge economic losses. Streptococcus agalactiae is a major contagious mastitis pathogen and continues to be a major cause of mastitis in dairy cattle and buffaloes. The aim of the study was to investigate the virulence determinants of S. agalactiae strains isolated from buffalo milk. Within the scope of the study, 24 S. agalactiae isolates from buffalo mastitis were examined. Biofilm production of isolates was investigated phenotypically by CRA method. It was observed that 18 (75%) isolates were positive for biofilm production. The presence of hylB, fnbB, scpB and spb1 virulence genes in S. agalactiae isolates were investigated by PCR. It was determined that 19 (79.17%) of the isolates were positive for scpB and 6 (25%) for fnbB virulence genes. None of the isolates were found to contain hylB and spb1 virulence genes. The antibiotic resistance profiles of the isolates among kanamycin, ampicillin, enrofloxacin, erythromycin, tetracycline, trimethoprim-sulfamethoxazole antibiotic discs were determined by Kirby Bauer Disc Diffusion Method. Resistance were evaluated as % 41.7, % 45.9, % 25, % 12.5, % 20.9, and % 33.3, respectively. RAPD-PCR patterns of all isolates were determined using the ERIC-2 primer. The dendrograms of the RAPD patterns were plotted with the UPGMA method. It was determined that the isolates showed similarity between 59-95%. In conclusion, the research confirms the prevalence of various virulence genes in S. agalactiae isolated from buffalo mastitis. Further studies are therefore necessary to determine the molecular epidemiology and variability of S. agalactiae isolated from buffaloes, with the aim of improving mastitis control programs with regard to S. agalactiae.

In vitro sensitivity of Candida albicans isolates to antifungal agents and the effect of biofilms on the drug resistance rate

Background and objectives: The pathogenic species that is most frequently isolated from fungus infections is Candida albicans. The host's immune system, the severity of the infection, and the antifungal medication of choice all influence the management of these infections. Despite the advancement of novel antifungal medications, epidemiological investigations have demonstrated that resistance to antifungal agents in C. albicans strains is becoming a significant issue. The aims of this study were to (I) determine the prevalence of antifungal resistance in 53 oral Candida albicans isolates and (II) investigate the effect of biofilm production capacity on antifungal resistance rates. Methods: Fifty-three isolates of Candida albicans were evaluated for biofilm production using the Tissue Culture Plate Method (TCPM). The antifungal susceptibility pattern of these isolates for amphotericin B, caspofungin, anidulafungin, voriconazole, itraconazole, ketoconazole, and posaconazole was determined using the E-test. Results: The present study showed strong, moderate, weak, and negative biofilm production in 18.9%, 34.0%, 26.4%, and 20.8% of the C. albicans isolates, respectively. Amphotericin B, anidulafungin, and caspofungin effectively inhibited all of the tested isolates. The resistance rates of C. albicans isolates to fluconazole, itraconazole, ketoconazole, voriconazole, and posaconazole were 35.8%, 20.7%, 37.7%, 13.2%, and 20.7%, respectively. Strong and moderate biofilm-producing isolates displayed higher resistance rates compared to weak and negative biofilm producers. The majority of antifungal treatments showed a significant difference (p &lt;0.05)". Conclusion: Our results suggest that the study area has a higher prevalence of azole-resistant Candida albicans. Thus, there is an urgent need to develop a plan to decrease the overuse and unneeded adverse effects of antifungal medications. Testing for antifungal susceptibility and fungus culture will be helpful in monitoring resistance and providing therapy for patients. It was observed that the development of Candida albicans biofilms was correlated with the drug resistance component of oral Candida albicans isolates.

Evaluation of adhesin genes and risk factors associated with urinary tract infections by drug-resistant uropathogenic Escherichia coli in North of Iran.

Uropathogenic Escherichia coli (UPEC) isolates, have a wide variety of virulence factors to promote colonization and survival in the urinary tract. This study aimed to evaluate adhesin genes, biofilm formation ability, antibiotic resistance profiles of UPEC strains, and the related risk factors in patients with UTIs caused by drug-resistant UPEC. A total of 105 UPEC isolates were evaluated for biofilm formation using 96-well microtiter plates, the presence of adhesin genes by PCR assay and the antimicrobial susceptibility pattern using the disk diffusion method. Demographic and clinical characteristics of patients were investigated to identify predisposing factors for drug-resistant isolates. Out of 105 UPEC isolates, 84.8% were positive for biofilm formation. Biofilm-producing isolates exhibited a significantly higher prevalence of fimH, kpsMTII, csgA, afa/draBC, and pap adhesin genes compared to non-biofilm-producing strains (p < 0.05). The results also revealed that 52.4% of the isolates were ESBL-producing, and 84.8% were multidrug-resistant (MDR). Further analysis of antibiotic susceptibility among ESBL-producing strains showed the highest resistance rates to ampicillin, ciprofloxacin, and trimethoprim-sulfamethoxazole. Conversely, the highest susceptibility, in addition to carbapenems, was observed for fosfomycin, amikacin, cefoxitin, and nitrofurantoin. We identified hypertension as a potential risk factor for infection with ESBL-producing UPEC strains. Our results revealed a significant rate of drug resistance among UPEC isolates obtained from UTIs in our region. This underscores the importance of monitoring the empirical use of antibiotics and identifying specific risk factors in our geographical area to guide the selection of appropriate empirical treatment for UTIs.

Comparative Study of Biofilm and Non-Biofilm Producing Klebsiella pneumoniae with Special Reference to Metallo-Beta-Lactamase Production

Klebsiella pneumoniae is one of the most common bacteria among all biofilm-producing as well as the beta-lactamase producing strains, which is responsible for multi-drug resistance. For better therapeutic applications, it is important to detect the biofilm production by Klebsiella pneumoniae and their antibiogram along with the ability to produce ESBL, MBL, and AmpC β-lactamases. The aim of the study was to determine the prevalence of biofilm formation and ESBL, MBL, AmpC β-lactamase phenotypes in K. pneumoniae as well as the antibiogram of all (biofilm and MBL-producing and non-producing) isolates of K. pneumoniae. Isolates of K. pneumoniae were tested for biofilm formation by the Congo-red agar method. ESBL, MBL, and AmpC β-lactamase detection were done by both screening and confirmatory tests as per CLSI guidelines. The antibiogram was obtained by the Kirby-Bauer disc diffusion method. Among the total 100 isolates of K. pneumoniae, 40% were biofilm-producing. Most of them were from urine specimens. Out of biofilm-producing isolates, ESBL – 28%, MBL- 47% and AmpC β-lactamase- 25.8% producers were observed. K. pneumoniae isolates were seen to have maximum resistance to ceftazidime and maximum sensitivity to nitrofurantoin. Study findings suggest the importance of assessment of biofilm formation for better treatment. The scenario further worsens if such biofilm-producing isolates are also MBL-positive leading to limited therapeutic options.

Evaluation of PA0756 and toxA Gene Expression in Clinical Isolates of Pseudomonas aeruginosa and Its Comparison Between Biofilm-Producing and Planktonic Isolates

Background: Biofilm formation is crucial in the pathogenesis of Pseudomonas aeruginosa infections, contributing to increased antibiotic resistance. Objectives: This study aimed to evaluate the expression of the PA0756 and toxA genes in clinical isolates of P. aeruginosa, comparing biofilm-producing isolates with planktonic ones. Methods: In this cross-sectional study, 160 clinical isolates of P. aeruginosa were collected from hospitals in Tabriz. Biofilm development was assessed using a 96-well flat-bottom microtiter plate test, followed by polymerase chain reaction (PCR) amplification of the resistance genes PA0756 and toxA. DNA synthesis for both biofilm and planktonic P. aeruginosa was conducted, with the quantification of target genes carried out using real-time PCR with specific primers. Results: Of the isolates, 139 (87%) formed biofilms. These strains showed high resistance to gatifloxacin, piperacillin, gentamycin, and ceftazidime (82.25%, 72.97%, 76.12%, and 74.63%, respectively), while resistance to colistin and polymyxin B was low (2.5% and 3%, respectively). The expression study revealed significant upregulation of the PA0756 and toxA genes in biofilm formers by 1.2 - 5.6 fold and 1.2 - 2.5 fold, respectively, compared to planktonic cells (P = 0.012 and P = 0.041, respectively). Conclusions: The PA0756 and toxA genes are significantly involved in biofilm-specific antibiotic resistance in P. aeruginosa, presenting potential targets for therapeutic interventions against antibiotic resistance caused by this pathogen.

Detection of Extended Spectrum ß-Lactamase-Producing Escherichia coli with Biofilm Formation from Chicken Meat in Istanbul.

Antimicrobial resistance is one of the major public health problems worldwide. This study aimed to detect the presence of extended-spectrum β-lactamase-(ESBL-)producing Escherichia (E.) coli in chicken meat in Istanbul, Türkiye. Raw chicken meat samples (n = 208) were collected from different sale points and analyzed for ESBL-producing E. coli. In total, 101 (48.5%) isolates were confirmed as E. coli by PCR, of which 80/101 (79.2%) demonstrated multiple antibiotic resistance. Resistance against amoxicillin-clavulanic acid was most frequent (87.1%). Eighteen isolates (17.8%) demonstrated phenotypical ESBL resistance, as assessed by the double disc synergy test (DDST). Isolates were tested for the presence of β-lactamase genes and mobilized colistin-resistant genes. The blaTEM group was most frequently detected (97.02%), followed by blaCTX m (45.5%), blaSHV (9.9%), and blaOXA-2 (0.9%). However, mcr genes and blaNDM,blaKPC, blaVIM, and blaOXA-48 genes were not found in any isolate. E. coli strains were tested for biofilm formation in six different media [Nutrient broth, LB broth, Tryptone Soya broth (TSB), TSB containing 1% sucrose, TSB containing 0.6% yeast extract, and BHI]. Biofilm formation by E. coli isolates (44/101, 43.5%) was highest in TSB with 1% sucrose. It is worth noting that all biofilm-producing isolates were found to harbor the blaTEM-1 gene, which can indicate a high level of antibiotic resistance. This is the first report about ESBL-producing E. coli in poultry meat, the exposure of consumers in Istanbul metropolitan areas, and the ability of E. coli from this region to produce biofilms.

In vitro and in vivo evaluation of the biofilm-degrading Pseudomonas phage Motto, as a candidate for phage therapy.

Infections caused by Pseudomonas aeruginosa are becoming increasingly difficult to treat due to the emergence of strains that have acquired multidrug resistance. Therefore, phage therapy has gained attention as an alternative to the treatment of pseudomonal infections. Phages are not only bactericidal but occasionally show activity against biofilm as well. In this study, we describe the Pseudomonas phage Motto, a T1-like phage that can clear P. aeruginosa infections in an animal model and also exhibits biofilm-degrading properties. The phage has a substantial anti-biofilm activity against strong biofilm-producing isolates (n = 10), with at least a twofold reduction within 24 h. To demonstrate the safety of using phage Motto, cytotoxicity studies were conducted with human cell lines (HEK 293 and RAW 264.7 macrophages). Using a previously established in vivo model, we demonstrated the efficacy of Motto in Caenorhabditis elegans, with a 90% survival rate when treated with the phage at a multiplicity of infection of 10.

Biofilm formation and antimicrobial resistance pattern of uropathogenic E. coli ST131 isolated from children with malignant tumors

The multidrug-resistant clone identified as Escherichia coli sequence type 131 (E. coli ST131) has spread world-wide. This study sought to ascertain the frequency and biofilm formation of E. coli ST131 isolated from children with various malignancies. A total of 60 uropathogenic E. coli (UPEC) isolates from children without cancer and 30 UPEC isolates from children with cancer were assessed in this study. The microdilution method was used to investigate the sensitivity of bacteria to antibiotics. The microtiter plate (MTP) approach was used to phenotypically assess biofilm formation. The lasR, pelA, and lecA biofilm-encoding genes were detected by PCR in biofilm-producing isolates of E. coli. Thirty-seven out of 90 E. coli isolates were found to be ST131 (41.1%), with 17 (56.7%) from cancer-affected children and 20 (33.3%) from children without cancer, respectively (P-value = 0.036). The frequency of antimicrobial resistance was higher in ST131 strains were compared to non-ST131 strains and when they were isolated from healthy children vs. those who had cancer. In contrast to non-ST131 isolates, ST131 isolates were more biofilm-producers. There was a significant difference between the percentage of biofilm producers between the 22 (100%) ST131-O16 isolates and the 13 (86.7%) ST131-O25b isolates (P-value = 0.04). Children with cancer are more likely than children without cancer to develop biofilm forming E. coli ST131, the latter having a higher profile of antibiotic resistance. Interestingly, E. coli ST131 isolates from non-cancer patients had higher levels of overall antibiotic resistance and while more E. coli ST131isolates from cancer patients formed biofilms.

Effect of Potassium Permanganate on Staphylococcal Isolates Derived from the Skin of Patients with Atopic Dermatitis.

In atopic dermatitis (AD), Staphylococcus aureus frequently colonizes lesions, leading to superinfections that can then lead to exacerbations. The presence of biofilm-producing isolates has been associated with worsening of the disease. Potassium permanganate is used as a topical treatment of infected eczema, blistering conditions, and wounds. Little is known of its effects against microbes in AD skin. The aim of this study was to explore antibacterial and antibiofilm properties of potassium permanganate against staphylococcal isolates derived from AD skin. Viable count and radial diffusion assays were used to investigate antibacterial effects of potassium permanganate against planktonic staphylococcal isolates. The antibiofilm effects were assessed using biofilm assays and scanning electron microscopy. The Staphylococcus aureus isolates were completely killed when exposed to 0.05% of potassium permanganate. In concentrations of 0.01%, potassium permanganate inhibited bacterial biofilm formation. Eradication of established staphylococcal biofilm was observed in concentrations of 1%. Electron microscopy revealed dense formations of coccoidal structures in growth control and looser formations of deformed bacteria when exposed to potassium permanganate. This suggests antibacterial and antibiofilm effects of potassium permanganate against staphylococcal isolates derived from AD skin, when tested in vitro, and a potential role in the treatment of superinfected AD skin.

Inhibitory effect of selenium nanoparticles on the biofilm formation of multidrug-resistant Acinetobacter baumannii

Background/Aim: Treatment of infections caused by biofilm-producing multidrug-resistant (MDR) pathogens represents a huge global problem due to primary antimicrobial multi-resistance enhanced by reduced penetration of antibiotics in the biofilm-embedded bacteria. The aim of this study was to determine the capacity of biofilm production among MDR Acine-tobacter baumannii (A. baumannii) isolates obtained from different clinical specimens and to evaluate the inhibitory effect of selenium nanoparticles (SeNPs) coated with cationic polymer cetyltrimethylammonium bromide (CTAB) on the biofilm formation. Methods: Antimicrobial effect of antibiotics (meropenem, imipenem, gentamicin, amikacin, ciprofloxacin, levofloxacin and trimethoprim-sulfa-methoxazole) was determined by disk-diffusion assay, while sensitivity to colistin was determined with E test. All 60 isolates were tested on biofilm production in microtiter plates with crystal violet dye. Minimal biofilm inhib-itory concentration (MBIC) of SeNPs was tested in order to prevent biofilm formation in microtiter plates. Results: All tested clinical isolates were classified as MDR (n = 60) and extensively drug-resistant (XDR, n = 60). Out of the total 60 isolates, 55 isolates (92 %) showed the ability for biofilm formation, with the majority of them classified as strong (42 %) and moderate (42 %) biofilm producers. MBIC values of SeNPs for 55 biofilm-producing isolates ranged from 0.07 to 1.25 mg/mL. Strong biofilm producers had statistically higher MBIC (0.15 mg/mL) in correlation to other biofilm-producing isolates (0.07 mg/ mL). There was no correlation between invasiveness of isolates with biofilm production and MBIC values. Conclusion: Presented results are very promising and interesting especially in nanotechnology and medical fields, while SeNPs with the addition of cationic surfactant inhibit biofilm formation of MDR A. baumannii clinical isolates.

Myrtenol's Effectiveness against Hospital-Acquired Methicillin-Resistant Staphylococcus aureus: Targeting Antibiofilm and Antivirulence Properties.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) several years ago highlighted the challenge of multidrug-resistant infections, emphasizing the critical need for innovative treatment approaches. Myrtenol, known for its antibacterial and antibiofilm properties, holds promise as a potential treatment option. This study aimed to evaluate the effectiveness of myrtenol against MRSA. The collected MRSA isolates were assessed for antimicrobial susceptibility following the Clinical and Laboratory Standards Institute (CLSI) guidelines 2023. Biofilm formation by MRSA was evaluated using the tissue culture plate (TCP) technique. The minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and minimal biofilm inhibitory concentration (MBIC) of myrtenol against MRSA were determined both individually and in combination with antibiotics. Real-time PCR was employed to investigate the impact of myrtenol on the expression of virulence genes (sarA, agrA, and icaD) across the isolates. In this study, MRSA was identified in 90 out of 400 cases (22.5%) of hospital-acquired pathogens. Among the collected MRSA isolates, 53 out of 90 (59%) were found to produce biofilms. The MIC of myrtenol was comparable to the MBC across all tested isolates, they were almost the same. Combinations of myrtenol with most tested antibiotics exhibited synergistic effects exceeding 60%. Among the 53 biofilm-producing isolates, 45 isolates (85%) expressed the sarA gene, 49% expressed the agrA gene, and all biofilm-producing MRSA isolates (100%) expressed the icaD gene. A notable reduction in the relative quantity (RQ) values of virulence gene expression was observed after treatment with the MBIC of myrtenol across all tested isolates. Myrtenol demonstrated strong antimicrobial activity against MRSA, notably reducing the expression of key virulence genes linked to biofilm formation. This suggests its potential as a therapeutic agent for treating biofilm-associated MRSA infections.

Catheter-associated urinary tract infection and biofilms: Dreaded duo in health settings

Abstract Background: Urinary tract infections (UTIs) alone account for 30% of hospital infections, 80% of these are catheter-associated UTIs (CAUTI). Microbial film in indwelling medical devices worsens the existing medical condition and leads to multidrug resistance (MDR) and prolonged hospital stay. This cross-sectional study was done to find out the organisms causing CAUTI, their sensitivity pattern, the proportion of biofilm formation, and the sensitivity, specificity of different procedures in the demonstration of biofilm. Materials and Methods: Urine sample was collected from 307 patients with indwelling catheters. Direct Gram stain was performed from well-mixed uncentrifuged urine. Specimens were processed, organisms were isolated by standard microbiological procedures, and antimicrobial sensitivity testing was performed. Various methods such as Congo red agar, tube adherence, and microtiter plate methods were used to identify biofilm formation for all the isolates. Results: Out of 307 catheterized urine samples, a direct Gram stain was positive in 137 (44.62%) samples and culture positive in 148 (48.2%) samples. Out of 134 bacterial isolates, biofilm was observed by Congo red agar in 36 (27%), tube adherence in 59 (44%), and microtiter plate in 80 (60%) isolates. Escherichia coli (50.74%) was the predominant isolate followed by Klebsiella spp (26.11%). MDR was observed in 53 (66%) biofilm-forming isolates. Conclusions: Catheterized patients are prone to develop a microbial biofilm that is multidrug resistant and burdensome. Of the 80 biofilm-producing isolates, MDR was observed in 53 (66%). The effective ways to prevent CAUTI are strict adherence to indications for catheterization and, a bundle care approach with a preinsertion checklist.

In vitro evaluation of biofilm phenotypic and genotypic characteristics among clinical isolates of Pseudomonas aeruginosa in Hamadan, West of Iran.

Due to high antimicrobial resistance and biofilm-forming ability, Pseudomonas aeruginosa is one of the seriously life-threatening agents causing chronic and nosocomial infections. This study was performed to determine the antibiotic resistance pattern, biofilm formation, and frequency of biofilm-related genes in P. aeruginosa strains. In total, 123 P. aeruginosa isolates were collected from different clinical sources. Antimicrobial susceptibility testing (AST) was performed to detect multidrug-resistant P. aeruginosa (MDRPA) isolates. To evaluate the biofilm-forming isolates, the microtiter plate (MTP) method was carried out. Also, the prevalence of biofilm genotype patterns, including pslA, pslD, pelA, pelF, and algD genes, was detected by polymerases chain reaction (PCR). According to our findings, the highest resistance and susceptibility rates were found in ceftazidime with 74.7% (n = 92) and ciprofloxacin with 42.2% (n = 52), respectively. In our study, the highest level of antibiotic resistance belonged to wound isolates which meropenem had the most antibacterial activity against them. In total, 86.1% (n = 106) P. aeruginosa isolates were determined as MDRPA, of which 61.3% (n = 65) were able to form strong biofilm. The highest and lowest frequency of biofilm-related genes among biofilm producer isolates belonged to pelF with 82.1% (n = 101) and algD with 55.2% (n = 68), respectively. The findings of the conducted study indicate a significant relationship between MDRPA and biofilm genotypic/phenotypic patterns, suggesting the necessity of a careful surveillance program in hospital settings.

Diversity of biofilm-specific antimicrobial resistance genes in Pseudomonas aeruginosa recovered from various clinical isolates.

The resistance of Pseudomonas aeruginosa to antibiotics offers a significant challenge in the treatment of patients. This study aimed to investigate the antimicrobial resistance profile, biofilm-specific antimicrobial resistance genes, and genetic diversity of P. aeruginosa recovered from clinical samples. Totally 47 non-duplicate isolates of P. aeruginosa were recovered from various clinical samples. toxA, algD, ndvB, and tssC1 genes were detected in biofilm-producing isolates. The DNA sequences of the toxA and tssC1 genes were analyzed, by creating phylogenetic trees. The findings revealed that 30 (63.8%) of the isolates tested positive for Extended spectrum β-lactamase (ESBL), whereas 31 (65.9%) tested positive for Metallo-β-lactamase (MBL) and all of the isolates presented the toxA genes, and 19.1%,17%, 6.3% presented by algD, ndvB and tssC1 genes. Besides, the phylogenetic trees of the toxA and tssC1 gene isolates suggested a genotype that was closely aligned with others. Gene sequencing similarity revealed 99% identity with other isolates deposited in GenBank. The occurrence of toxA was most prevalent. One isolate was recorded as a novel isolate in the global gene bank as a locally isolated strain from the city of Erbil that has never been identified in global isolates due to genetic variation.

Sub-inhibitory concentrations of ceftriaxone induce morphological alterations and PIA-independent biofilm formation in Staphylococcus aureus

The exposure of bacteria to sub-inhibitory concentrations of antibiotics is of biological significance since it can occur in vivo under many circumstances, including low-dose treatment, poor adherence to a regimen, poor drug penetration, drug-drug interactions, and antibiotic resistance of the pathogen. In this study, we investigated the effects of subinhibitory concentrations of four antibiotics: ampicillin, ceftriaxone, gentamicin, and norfloxacin, which are commonly used in clinical settings and on cell morphology and biofilm formation in Staphylococcus aureus as one of the leading causes of nosocomial and biofilm-associated infections. Nine clinical S. aureus biofilm-producing isolates and two known biofilm-producing reference strains, S. aureus ATCC 29213 and S. aureus ATCC 6538, were used in this study. Sub-MICs of beta-lactam antibiotics (ampicillin and ceftriaxone) significantly induced biofilm formation in S. aureus ATCC 29213 and S. aureus ATCC 6538 and in six clinical isolates out of the nine selected isolates when compared with the antibiotic-free control group (P < 0.05), with an approximately 2- to 2.5-fold increase. Gentamicin and norfloxacin induced biofilms in S. aureus ATCC 29213 and S. aureus ATCC 6538, while gentamicin and norfloxacin induced biofilms only in three and two of the nine tested isolates, respectively (P < 0.05). The chemical nature of the biofilm matrix produced by half the MIC of ceftriaxone in the six isolates that showed increased biofilm was all non-polysaccharide in composition (PIA-independent). Gene expression of biofilm-encoding genes atl and sarA in biofilms of the two tested strains (S. aureus ATCC 6538) and clinical strain (S. aureus 16) showed a significant upregulation after exposure to half MIC of ceftriaxone. Additionally, the bacterial cell morphological changes in planktonic cells caused by half MIC of ceftriaxone were evaluated by scanning electron microscopy, which demonstrated a significant cell enlargement when compared with the antibiotic-free control (P < 0.05), and some deformed cells were also noticed. In S. aureus clinical isolates, sub-MICs of ampicillin, ceftriaxone, gentamicin, and norfloxacin may stimulate substantial production of biofilm, which could have important clinical significance and make infection treatment challenges. Further, in vivo research is needed to fully comprehend how sub-MIC of antibiotics can affect biofilm formation in clinical settings. Additionally, more research is required to reveal the clinical implications of the morphological alterations in S. aureus brought on by exposure to ceftriaxone at concentrations below its MIC.Graphical

Evaluation of thymol effect on antimicrobial susceptibility and biofilm production in clinical Enterobacter spp. producing ESBLs and KPC enzymes

ABSTRACT Background Multidrug-resistant Enterobacter strains that harbour Klebsiella pneumoniaecarbapenemase and Extended Spectrum β-Lactamases genes are a therapeuticchallenge in hospitals that have made infection control and antibiotic therapydifficult and use of natural compounds such as thymol is interesting in thetreatment of infections. Methods Sixty-seven Enterobacter spp. isolates were obtained from patients admittedto hospitals in Hamadan and Tehran. Antimicrobial susceptibility, ESBLs andKPC genes detection and biofilm production of isolates were measured. Findings The results showed that the highest and lowest antibiotic resistance wererelated to ceftazidime (82.1%) and tigecycline (3%), respectively. Also, 79.1% of the isolates were MDR. The highestpresence of genes was related to TEM (100%), SHV (82%), CTX-M(77%) and KPC (8.96%) genes. The MICand MBIC of thymol were obtained 8-31 μg/ml and16-62 μg/ml, respectively. Conclusion Use of thymol, as an aid in antibiotic therapy is recommended.