Association between biofilm-production and antibiotic resistance in Escherichia coli isolates: A laboratory-based case study and a literature review.

Bacteria can enhance their survival by attaching to inanimate surfaces or tissues, and presenting as multicellular communities encased in a protective extracellular matrix called biofilm. There has been pronounced interest in assessing the relationship between the antibiotic resistant phenotype and biofilm-production in clinically-relevant pathogens. The aim of the present paper was to provide additional experimental results on the topic, testing the biofilm-forming capacity of Escherichia coli isolates using in vitro methods in the context of their antibiotic resistance in the form of a laboratory case study, in addition to provide a comprehensive review of the subject. In our case study, a total of two hundred and fifty (n = 250) E. coli isolates, originating from either clean-catch urine samples (n = 125) or invasive samples (n = 125) were included. The colony morphology of isolates were recorded after 24h, while antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Biofilm-formation of the isolates was assessed with the crystal violet tube-adherence method. Altogether 57 isolates (22.8%) isolates were multidrug resistant (MDR), 89 isolates (35.6%) produced large colonies (>3 mm), mucoid variant colonies were produced in 131 cases (52.4%), and 108 (43.2%) were positive for biofilm formation. Biofilm-producers were less common among isolates resistant to third-generation cephalosporins and trimethoprim-sulfamethoxazole (P = 0.043 and P = 0.023, respectively). Biofilms facilitate a protective growth strategy in bacteria, ensuring safety against environmental stressors, components of the immune system and noxious chemical agents. Being an integral part of bacterial physiology, biofilm-formation is interdependent with the expression of other virulence factors (especially adhesins) and quorum sensing signal molecules. More research is required to allow for the full understanding of the interplay between the MDR phenotype and biofilm-production, which will facilitate the development of novel therapeutic strategies.

Effects of different decontaminating solutions used for the treatment of peri-implantitis on the growth of Porphyromonas gingivalis-an in vitro study.

Implants have been considered the treatment of choice to replace missing teeth, unfortunately, peri-implant disease is still an unresolved issue. Contaminated implants may be decontaminated by physical debridement and chemical disinfectants; however, there is a lack of consensus regarding the ideal techniques/agents to be used for the decontamination. The objective of our study was to compare the decontaminating efficacy of different chemical agents on a titanium surface contaminated with Porphyromonas gingivalis, a typical representative of the bacterial flora associated with peri-implantitis. Commercially pure Ti grade 4 discs with a polished surface were treated with a mouthwash containing chlorhexidine digluconate (0.1%), povidone-iodine (PVP-iodine) solution (10%) or citric acid monohydrate (40%). Qualitative and quantitative assessment of cellular growth and survival were assessed by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and scanning electron microscopy (SEM). Significant differences in the quantity of P. gingivalis could be observed after 6 days of incubation. A numerical, but not statistically significant (P = 0.066) decrease in the amount of living bacteria was observed in the group treated with the PVP-iodine solution as compared to the control group. The chlorhexidine (CHX)-treated group presented with significantly higher cell counts, as compared to the PVP-iodine-treated group (P = 0.032), while this was not observed compared to the control group and citric acid-treated group. Our results have also been verified by SEM measurements. Our results suggest that for P. gingivalis contamination on a titanium surface in vitro, PVP-iodine is a superior decontaminant, compared to citric acid and chlorhexidine-digulconate solution.

Comparison of effects of different fluoride containing prophylactics on the growth of Streptococcus mutans on titanium surfaces - an in vitro study.

The combined use of high fluoride (F-) concentration and acidic pH can weaken the corrosion resistance of titanium (Ti). Caries prophylactic products contain high amounts of F- and are applied at a low pH. The aim of our study was to determine whether the different forms of applied flouride has different effects on the growth of Streptococcus mutans on different titanium surfaces. Titanium with polished surface were treated with a gel (pH: 4,8) containing 1,25% olaflur, a rinse (pH: 4,4) containing 0,025% olaflur or a 1% aqueous solution of NaF at a pH of 4,5. Control discs were not treated. All discs were incubated with S. mutans for 21 days. To assess the amount of S. mutans protein assay analysis was performed at 5, 10 and 21 days. Scanning electron microscopic (SEM) investigations were also executed. By the 21st day significant differences could be observed in the bacterial protein quantity. The between group- comparisons showed that the rinse and gel were superior to NaF or control group (p < 0,01 and p < 0,05). Furthermore signs of corrosion could be observed in the group of gel treated discs. The results suggest that amine-fluoride content mouthwashes might be a suitable choice for prevention to the patients with dental implants.

Short- and Long-Term Influence of Fluoride-Containing Prophylactics on the Growth of Streptococcus mutans on Titanium Surface.

OBJECTIVES: Acidic pH and high fluoride (F(-)) concentration impair the corrosion resistance of titanium (Ti). Caries-preventive products contain high amounts of F(-) and are applied at low pH. The purpose of this study was to evaluate whether fluoride applied in different forms has different short-, mid-, and long-term effects on the growth of the bacteria Streptococcus mutans. MATERIALS AND METHODS: Ti discs with polished surface were treated with a rinse containing 0.025% olaflur, a gel containing 1.25% olaflur, or a 1% aqueous solution of NaF (pH 4.5), and they were incubated with S mutans for 21 days. Control discs did not get prophylactic treatment. Protein assay analysis was performed at regular intervals to estimate the amount of S mutans. Scanning electron microscopic (SEM) images were also taken. RESULTS: Bacterial protein quantity became significantly different only by the 21st day. Fluoride in rinse and gel proved to be superior to NaF in aqueous solution or no treatment (P < 0.01 and P < 0.05, respectively). However, the discs treated with fluoride in gel showed signs of corrosion in SEM images. CONCLUSION: The results suggest that the use of fluoride-containing mouthwashes might be the best and safest oral hygienic choice for patients with oral implants. Furthermore, olaflur seems to be superior to NaF for long-term use at low pH.

Prevalence of exocrine pancreatic insufficiency in type 2 diabetes mellitus with poor glycemic control.

OBJECTIVES: To evaluate the relationship between exocrine pancreatic insufficiency and the level of glycemic control in diabetes (DM). METHODS: Patients with type 2 DM treated in our clinic were prospectively recruited into the study. Pancreatic diabetes was excluded. Cases with HbA1c ≥7% formed Group A (n = 59), and with HbA1c <7% Group B (n = 42). The fecal level of pancreatic elastase (PE-1) was measured and morphological examinations of the pancreas were performed. RESULTS: The PE-1 level was significantly lower in Group A than in Group B (385.9 ± 171.1 µg/g, vs. 454.6 ± 147.3 µg/g, p = 0.038). The PE-1 level was not correlated with HbA1c (r = -0.132, p = 0.187), the duration of DM (r = -0.046, p = 0.65), age (r = 0.010, p = 0.921), BMI (r = 0.203, p = 0.059), or pancreatic steatosis (r = 0.117, p = 0.244). The size of the pancreas did not differ significantly between Groups A and B. CONCLUSIONS: An exocrine pancreatic insufficiency demonstrated by fecal PE-1 determination is more frequent in type 2 DM patients with poor glycemic control. The impaired exocrine pancreatic function cannot be explained by an alteration in the size of the pancreas or by pancreatic steatosis.

Awareness of Chronic Kidney Disease, Medication, and Laboratory Investigation among Nephrology and Urology Patients of Quetta, Pakistan.

Patients' awareness is critical in medical care, as it can serve as an input into the adjustment of interventions. The aim of study was to explore the level of awareness regarding chronic kidney disease (CKD), its medications, and laboratory investigations among nephrology and urology patients of Quetta. The cross-sectional study was used by adopting and culturally modifying a questionnaire. By convenient sampling technique, a total of 500 questionnaires were self-administered to inpatients, outpatients, and dialysis patients, and 468 responses (response rate 93.6%) were analyzed. Descriptive statistics, inferential statistics, and reliability analysis were performed on SPSS v25. A majority, 50.3% (n = 235), was unaware of symptoms that will develop due to worsening of disease, while 56.2% (n = 263) were unaware of what aggravates their kidney function. Almost half of the affected individuals, 47.4% (n = 222), have no understanding about the long-term prognosis of the disease. The majority of the respondents, 51.5% (n = 248), do not know about the names and usage of medications, and 62.4% (n = 292) were unaware of the medicines that may impair kidney function; more than half, 66.7% (n = 312), were unaware about the necessary laboratory investigations. A strong association between awareness and patient education level was found (p < 0.001). Awareness regarding disease condition, medications, and laboratory investigations of CKD among nephrology and urology patients of Quetta was found out to be low, which needs immediate educational intervention.

No Correlation between Biofilm-Forming Capacity and Antibiotic Resistance in Environmental Staphylococcus spp.: In Vitro Results.

The production of biofilms is a critical factor in facilitating the survival of Staphylococcus spp. in vivo and in protecting against various environmental noxa. The possible relationship between the antibiotic-resistant phenotype and biofilm-forming capacity has raised considerable interest. The purpose of the study was to assess the interdependence between biofilm-forming capacity and the antibiotic-resistant phenotype in 299 Staphylococcus spp. (S. aureus n = 143, non-aureus staphylococci [NAS] n = 156) of environmental origin. Antimicrobial susceptibility testing and detection of methicillin resistance (MR) was performed. The capacity of isolates to produce biofilms was assessed using Congo red agar (CRA) plates and a crystal violet microtiter-plate-based (CV-MTP) method. MR was identified in 46.9% of S. aureus and 53.8% of NAS isolates (p > 0.05), with resistance to most commonly used drugs being significantly higher in MR isolates compared to methicillin-susceptible isolates. Resistance rates were highest for clindamycin (57.9%), erythromycin (52.2%) and trimethoprim-sulfamethoxazole (51.1%), while susceptibility was retained for most last-resort drugs. Based on the CRA plates, biofilm was produced by 30.8% of S. aureus and 44.9% of NAS (p = 0.014), while based on the CV-MTP method, 51.7% of S. aureus and 62.8% of NAS were identified as strong biofilm producers, respectively (mean OD570 values: S. aureus: 0.779±0.471 vs. NAS: 1.053±0.551; p < 0.001). No significant differences in biofilm formation were observed based on MR (susceptible: 0.824 ± 0.325 vs. resistant: 0.896 ± 0.367; p = 0.101). However, pronounced differences in biofilm formation were identified based on rifampicin susceptibility (S: 0.784 ± 0.281 vs. R: 1.239 ± 0.286; p = 0.011). The mechanistic understanding of the mechanisms Staphylococcus spp. use to withstand harsh environmental and in vivo conditions is crucial to appropriately address the therapy and eradication of these pathogens.

Relationship between Biofilm-Formation, Phenotypic Virulence Factors and Antibiotic Resistance in Environmental Pseudomonas aeruginosa

The formation of a protective biofilm by Pseudomonas aeruginosa (PA) is one of the hallmarks of their survival both in vivo and in harsh environmental conditions, thus, biofilm-eradication has relevance from therapeutic perspectives and for infection control. The aim of our study was to investigate the possible relationship between antibiotic resistance, biofilm-forming capacity and virulence factors in n = 166 PA isolates of environmental origin. Antimicrobial susceptibility testing and the phenotypic detection of resistance determinants were carried out using standard protocols. The biofilm-forming capacity of PA was tested using a standardized crystal violet microtiter plate-based method. Motility (swimming, swarming, and twitching) and siderophore production of the isolates were also assessed. Resistance rates were highest for ciprofloxacin (46.98%), levofloxacin (45.18%), ceftazidime (31.92%) and cefepime (30.12%); 19.28% of isolates met the criteria to be classified as multidrug-resistant (MDR). Efflux pump overexpression, AmpC overexpression, and modified Hodge-test positivity were noted in 28.31%, 18.07% and 3.61%, respectively. 22.89% of isolates were weak/non-biofilm producers, while 27.71% and 49.40% were moderate and strong biofilm producers, respectively. Based on MDR status of the isolates, no significant differences in biofilm-production were shown among environmental PA (non-MDR OD570 [mean ± SD]: 0.416 ± 0.167 vs. MDR OD570: 0.399 ± 0.192; p > 0.05). No significant association was observed between either motility types in the context of drug resistance or biofilm-forming capacity (p > 0.05). 83.13% of isolates tested were positive for siderophore production. The importance of PA as a pathogen in chronic and healthcare-associated infections has been described extensively, while there is increasing awareness of PA as an environmental agent in agriculture and aquaculture. Additional studies in this field would be an important undertaking to understand the interrelated nature of biofilm production and antimicrobial resistance, as these insights may become relevant bases for developing novel therapeutics and eradication strategies against PA.

Antimicrobial Resistance in the Context of the Sustainable Development Goals: A Brief Review.

The reduction in infectious disease morbidity and mortality may be attributed to a variety of factors; however, improved sanitation and public health, and the introduction of vaccines and antibiotics are among the most significant. The development of antimicrobial resistance (AMR) in bacterial pathogens is an expected consequence of evolutionary adaptation to these noxious agents and the widespread use of these drugs has significantly sped up this process. Infections caused by multidrug resistant pathogens are directly associated with worse clinical outcomes, longer hospital stays, excess mortality in the affected patients and an increasing burden and costs on the healthcare infrastructure. The Sustainable Development Goals (SDGs) were published in 2015 by the United Nations to serve as a global blueprint for a better, more equitable, more sustainable life on our planet. The SDGs contextualize AMR as a global public health and societal issue; in addition, the continuing emergence of AMR may limit the attainment on many SDGs. The aim of this mini-review is to provide insight on the interface between attainment of SDGs and the clinical problem of drug resistance in bacteria.

Correlation Between Biofilm-Formation and the Antibiotic Resistant Phenotype in Staphylococcus aureus Isolates: A Laboratory-Based Study in Hungary and a Review of the Literature.

INTRODUCTION: Staphylococcus aureus (S. aureus) is an important causative pathogen in human infections. The production of biofilms by bacteria is an important factor, leading to treatment failures. There has been significant interest in assessing the possible relationship between the multidrug-resistant (MDR) status and the biofilm-producer phenotype in bacteria. The aim of our present study was to assess the biofilm-production rates in clinical methicillin-susceptible S. aureus [MSSA] and methicillin-resistant S. aureus [MRSA] isolates from Hungarian hospitals and the correlation between resistance characteristics and their biofilm-forming capacity. METHODS: A total of three hundred (n=300) S. aureus isolates (corresponding to MSSA and MRSA isolates in equal measure) were included in this study. Identification of the isolates was carried out using the VITEK 2 ID/AST system and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and E-tests, confirmation of MRSA status was carried out using PBP2a agglutination assay. Biofilm-production was assessed using the crystal violet (CV) tube-adherence method and the Congo red agar (CRA) plate method. RESULTS: There were significant differences among MSSA and MRSA isolates regarding susceptibility-levels to commonly used antibiotics (in case of erythromycin, clindamycin and ciprofloxacin: p<0.001, gentamicin: p=0.023, sulfamethoxazole/trimethoprim: p=0.027, rifampin: p=0.037). In the CV tube adherence-assay, 37% (n=56) of MSSA and 39% (n=58) of MRSA isolates were positive for biofilm-production, while during the use of CRA plates, 41% (n=61) of MSSA and 44% (n=66) of MRSA were positive; no associations were found between methicillin-resistance and biofilm-production. On the other hand, erythromycin, clindamycin and rifampin resistance was associated with biofilm-positivity (p=0.004, p<0.001 and p<0.001, respectively). Biofilm-positive isolates were most common from catheter-associated infections. DISCUSSION: Our study emphasizes the need for additional experiments to assess the role biofilms have in the pathogenesis of implant-associated and chronic S. aureus infections.