Dual action of benzaldehydes: Inhibiting quorum sensing and enhancing antibiotic efficacy for controlling Pseudomonas aeruginosa biofilms

Quorum sensing (QS) has a central role in biofilm lifestyle and antimicrobial resistance, and disrupting these signaling pathways is a promising strategy to control bacterial pathogenicity and virulence. In this study, the efficacy of three structurally related benzaldehydes (4-hydroxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde (vanillin) and 4-hydroxy-3,5-dimethoxybenzaldehyde (syringaldehyde)) in disrupting the las and pqs systems of Pseudomonas aeruginosa was investigated using bioreporter strains and computational simulations. Additionally, these benzaldehydes were combined with tobramycin and ciprofloxacin antibiotics to evaluate their ability to increase antibiotic efficacy in preventing and eradicating P. aeruginosa biofilms. To this end, the total biomass, metabolic activity and culturability of the biofilm cells were determined. In vitro assays results indicated that the aromatic aldehydes have potential to inhibit the las and pqs systems by > 80 %. Molecular docking studies supported these findings, revealing the aldehydes binding in the same pocket as the natural ligands or receptor proteins (LasR, PQSA, PQSE, PQSR). Benzaldehydes were shown to act as virulence factor attenuators, with vanillin achieving a 48 % reduction in pyocyanin production. The benzaldehyde-tobramycin combination led not only to a 60 % reduction in biomass production but also to a 90 % reduction in the metabolic activity of established biofilms. A similar result was observed when benzaldehydes were combined with ciprofloxacin. 4-Hydroxybenzaldehyde demonstrated relevant action in increasing biofilm susceptibility to ciprofloxacin, resulting in a 65 % reduction in biomass. This study discloses, for the first time, that the benzaldehydes studied are potent QS inhibitors and also enhancers of antibiotics antibiofilm activity against P. aeruginosa.

Montelukast and cefoperazone act as antiquorum sensing and antibiofilm agents against Pseudomonas aeruginosa

AIMS

Drug repurposing is an attractive strategy to control biofilm-related infectious diseases. In this study, two drugs (montelukast and cefoperazone) with well-established therapeutic applications were tested on Pseudomonas aeruginosa quorum sensing (QS) inhibition and biofilm control.

METHODS AND RESULTS

The activity of montelukast and cefoperazone was evaluated for Pqs signal inhibition, pyocyanin synthesis, and prevention and eradication of Ps. aeruginosa biofilms. Cefoperazone inhibited the Pqs system by hindering the production of the autoinducer molecules 2-heptyl-4-hydroxyquinoline (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (the Pseudomonas quinolone signal or PQS), corroborating in silico results. Pseudomonas aeruginosa pyocyanin production was reduced by 50%. The combination of the antibiotics cefoperazone and ciprofloxacin was synergistic for Ps. aeruginosa biofilm control. On the other hand, montelukast had no relevant effects on the inhibition of the Pqs system and against Ps. aeruginosa biofilm.

CONCLUSION

This study provides for the first time strong evidence that cefoperazone interacts with the Pqs system, hindering the formation of the autoinducer molecules HHQ and PQS, reducing Ps. aeruginosa pathogenicity and virulence. Cefoperazone demonstrated a potential to be used in combination with less effective antibiotics (e.g. ciprofloxacin) to potentiate the biofilm control action.

Optical characterization and through-focus performance of two advanced monofocal intraocular lenses

PURPOSE

To compare the refractive power profile, subjective depth-of-field and objective optical quality of two advanced monofocal intraocular lenses (IOLs) designed to improve intermediate vision.

METHODS

This prospective study evaluated forty-six eyes of twenty-three patients, aged 54-68 years, binocularly implanted with two monofocal enhanced intraocular lenses (IOLs), the Tecnis Eyhance and the Physiol Isopure. Subjective through-focus visual acuity curves were obtained by placing trial lenses in front of the eye while wearing its best spherical-cylindrical correction for distance. Objective optical quality was defined as the area under the modulation transfer function, calculated from the wavefront maps measured with a high-resolution aberrometer. The optical design of both lenses was compared based on their refractive power profiles measured with the lenses immersed in saline solution.

RESULTS

Both lenses have progressive aspherical geometries, in which the sagittal power decreases rapidly from the center to the edge of the optical zone. Mean monocular through-focus curves show a best corrected distance visual acuity of - 0.02 logMAR with both lenses. Through-focus visual acuity was marginally higher for the Eyhance, with a difference of 1 letter at the defocus position of - 0.5D and 3 letters between - 1.0D and - 2.0D. Objective assessment of optical quality revealed only a difference of about 2 points in MTF area at distance.

CONCLUSION

Both IOLs use a similar approach to improve intermediate vision. The Eyhance showed marginally better subjective performance than the Isopure at the target vergences between - 1.00D and - 2.00D, although these results did not reach statistical significance and were not replicated by the objective findings.

Visible-light photoactivated proanthocyanidin and kappa-carrageenan coating with anti-adhesive properties against clinically relevant bacteria

The increase of bacterial resistance to antibiotics is a growing concern worldwide and the search for new therapies could cost billions of dollars and countless lives. Inert surfaces are major sources of contamination due to easier adhesion and formation of bacterial biofilms, hindering the disinfection process. Therefore, the objective of this study was to develop a photoactivatable and anti-adhesive kappa-carrageenan coating using proanthocyanidin as a photosensitizer. The complete reduction (>5-log10 CFU/cm3) of culturable cells of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa pathogens was achieved after 30 min of exposure to visible light (420 nm; 30 mW/cm2) with 5 % (w/v) of the photosensitizer. Cell membrane damage was confirmed by measuring potassium leakage, epifluorescence microscopy and bacterial motility analysis. Overall, visible light irradiation on coated solid surfaces mediated by proanthocyanidin showed no cytotoxicity and inactivated clinically important pathogens through the generation of reactive oxygen species, inhibiting bacterial initial adhesion. The developed coating is a promising alternative for a wide range of applications related to surface disinfection and food biopreservation.

Efficacy of Novel Quaternary Ammonium and Phosphonium Salts Differing in Cation Type and Alkyl Chain Length against Antibiotic-Resistant Staphylococcus aureus

Antibacterial resistance poses a critical public health threat, challenging the prevention and treatment of bacterial infections. The search for innovative antibacterial agents has spurred significant interest in quaternary heteronium salts (QHSs), such as quaternary ammonium and phosphonium compounds as potential candidates. In this study, a library of 49 structurally related QHSs was synthesized, varying the cation type and alkyl chain length. Their antibacterial activities against Staphylococcus aureus, including antibiotic-resistant strains, were evaluated by determining minimum inhibitory/bactericidal concentrations (MIC/MBC) ≤ 64 µg/mL. Structure-activity relationship analyses highlighted alkyl-triphenylphosphonium and alkyl-methylimidazolium salts as the most effective against S. aureus CECT 976. The length of the alkyl side chain significantly influenced the antibacterial activity, with optimal chain lengths observed between C10 and C14. Dose-response relationships were assessed for selected QHSs, showing dose-dependent antibacterial activity following a non-linear pattern. Survival curves indicated effective eradication of S. aureus CECT 976 by QHSs at low concentrations, particularly compounds 1e, 3e, and 5e. Moreover, in vitro human cellular data indicated that compounds 2e, 4e, and 5e showed favourable safety profiles at concentrations ≤ 2 µg/mL. These findings highlight the potential of these QHSs as effective agents against susceptible and resistant bacterial strains, providing valuable insights for the rational design of bioactive QHSs.

Phytochemicals and quaternary phosphonium ionic liquids: Connecting the dots to develop a new class of antimicrobial agents

INTRODUCTION

The infections by multidrug-resistant bacteria are a growing threat to human health, and the efficacy of the available antibiotics is gradually decreasing. As such, new antibiotic classes are urgently needed.

OBJECTIVES

This study aims to evaluate the antimicrobial activity, safety and mechanism of action of phytochemical-based triphenylphosphonium (TPP+) conjugates.

METHODS

A library of phytochemical-based TPP+ conjugates was repositioned and extended, and its antimicrobial activity was evaluated against a panel of Gram-positive (methicillin-resistant Staphylococcus aureus - MRSA) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii) and fungi (Candida albicans, Cryptococcus neoformans var. grubii). The compounds' cytotoxicity and haemolytic profile were also evaluated. To unravel the mechanism of action of the best compounds, the alterations in the surface charge, bacterial membrane integrity, and cytoplasmic leakage were assessed.

RESULTS

Structure-activity-toxicity data revealed the contributions of the different structural components (phenolic ring, carbon-based spacers, carboxamide group, alkyl linker) to the compounds' bioactivity and safety. Dihydrocinnamic derivatives 5 m and 5n stood out as safe, potent and selective antibacterial agents against S. aureus (MIC < 0.25 µg/mL; CC50 > 32 µg/mL; HC10 > 32 µg/mL). Mechanistic studies suggest that the antibacterial activity of compounds 5 m and 5n may result from interactions with the bacterial cell wall and membrane.

CONCLUSIONS

Collectively, these studies demonstrate the potential of phytochemical-based TPP+ conjugates as a new class of antibiotics.

A procedure to harmonize the hydrodynamic force during microbial cultivation in shaking flasks

Shake flask cultivation is a routine technique in microbiology and biotechnology laboratories where cell growth can be affected by the hydrodynamic conditions, which depend on the agitation velocity, shaking diameter, and shake flask size. Liquid agitation is implemented inherently to increase aeration, substrate transfer to the cells, and prevent sedimentation, disregarding the role of hydrodynamics in microbial growth and metabolism. Here, we present a simple approach to help standardize the hydrodynamic forces in orbital shakers to increase the experimental accuracy and reproducibility and give students a better knowledge of the significance of the agitation process in microbial growth.

Beyond Penicillin: The Potential of Filamentous Fungi for Drug Discovery in the Age of Antibiotic Resistance

Antibiotics are a staple in current medicine for the therapy of infectious diseases. However, their extensive use and misuse, combined with the high adaptability of bacteria, has dangerously increased the incidence of multi-drug-resistant (MDR) bacteria. This makes the treatment of infections challenging, especially when MDR bacteria form biofilms. The most recent antibiotics entering the market have very similar modes of action to the existing ones, so bacteria rapidly catch up to those as well. As such, it is very important to adopt effective measures to avoid the development of antibiotic resistance by pathogenic bacteria, but also to perform bioprospecting of new molecules from diverse sources to expand the arsenal of drugs that are available to fight these infectious bacteria. Filamentous fungi have a large and vastly unexplored secondary metabolome and are rich in bioactive molecules that can be potential novel antimicrobial drugs. Their production can be challenging, as the associated biosynthetic pathways may not be active under standard culture conditions. New techniques involving metabolic and genetic engineering can help boost antibiotic production. This study aims to review the bioprospection of fungi to produce new drugs to face the growing problem of MDR bacteria and biofilm-associated infections.

Quorum sensing architecture network in Escherichia coli virulence and pathogenesis

Escherichia coli is a Gram-negative commensal bacterium of the normal microbiota of humans and animals. However, several E. coli strains are opportunistic pathogens responsible for severe bacterial infections including gastrointestinal and urinary tract infections. Due to the emergence of multidrug-resistant serotypes that can cause a wide spectrum of diseases, E. coli is considered one of the most troublesome human pathogens worldwide. Therefore, a more thorough understanding of its virulence control mechanisms is essential for the development of new anti-pathogenic strategies. Numerous bacteria rely on a cell density-dependent communication system known as quorum sensing (QS) to regulate several bacterial functions, including the expression of virulence factors. The QS systems described for E. coli include the orphan SdiA regulator, an autoinducer-2 (AI-2), an autoinducer-3 (AI-3) system, and indole, which allow E. coli to establish different communication processes to sense and respond to the surrounding environment. This review aims to summarise the current knowledge of the global QS network in E. coli and its influence on virulence and pathogenesis. This understanding will help to improve anti-virulence strategies with the E. coli QS network in focus.

The action of phytochemicals in biofilm control

Covering: 2009 to 2021Antimicrobial resistance is now rising to dangerously high levels in all parts of the world, threatening the treatment of an ever-increasing range of infectious diseases. This has becoming a serious public health problem, especially due to the emergence of multidrug-resistance among clinically important bacterial species and their ability to form biofilms. In addition, current anti-infective therapies have low efficacy in the treatment of biofilm-related infections, leading to recurrence, chronicity, and increased morbidity and mortality. Therefore, it is necessary to search for innovative strategies/antibacterial agents capable of overcoming the limitations of conventional antibiotics. Natural compounds, in particular those obtained from plants, have been exhibiting promising properties in this field. Plant secondary metabolites (phytochemicals) can act as antibiofilm agents through different mechanisms of action from the available antibiotics (inhibition of quorum-sensing, motility, adhesion, and reactive oxygen species production, among others). The combination of different phytochemicals and antibiotics have revealed synergistic or additive effects in biofilm control. This review aims to bring together the most relevant reports on the antibiofilm properties of phytochemicals, as well as insights into their structure and mechanistic action against bacterial pathogens, spanning December 2008 to December 2021.

Curcumin and 10-undecenoic acid as natural quorum sensing inhibitors of LuxS/AI-2 of Bacillus subtilis and LasI/LasR of Pseudomonas aeruginosa

The quorum sensing (QS) system is related to cell-to-cell communication as a function of population density, which regulates several physiological functions including biofilm formation and virulence gene expression. QS inhibitors have emerged as a promising strategy to tackle virulence and biofilm development. Among a wide variety of phytochemicals, many of them have been described as QS inhibitors. Driven by their promising clues, this study aimed to identify active phytochemicals against LuxS/autoinducer-2 (AI-2) (as the universal QS system) from Bacillus subtilis and LasI/LasR (as a specific QS system) of Pseudomonas aeruginosa, through in silico analysis followed by in vitro validation. The optimized virtual screening protocols were applied to screen a phytochemical database containing 3479 drug-like compounds. The most promising phytochemicals were curcumin, pioglitazone hydrochloride, and 10-undecenoic acid. In vitro analysis corroborated the QS inhibitory activity of curcumin and 10-undecenoic acid, however, pioglitazone hydrochloride showed no relevant effect. Inhibitory effects on LuxS/AI-2 QS system triggered reduction of 33-77% by curcumin (at 1.25-5 µg/mL) and 36-64% by 10-undecenoic acid (at 12.5-50 µg/mL). Inhibition of LasI/LasR QS system was 21% by curcumin (at 200 µg/mL) and 10-54% by 10-undecenoic acid (at 15.625-250 µg/mL). In conclusion, in silico analysis allowed the identification of curcumin and, for the first time, 10-undecenoic acid (showing low cost, high availability, and low toxicity) as alternatives to counteract bacterial pathogenicity and virulence, avoiding the imposition of selective pressure usually related to classic industrial disinfection and antibiotics therapy.

Hydrocinnamic Acid and Perillyl Alcohol Potentiate the Action of Antibiotics against Escherichia coli

The treatment of bacterial infections has been troubled by the increased resistance to antibiotics, instigating the search for new antimicrobial therapies. Phytochemicals have demonstrated broad-spectrum and effective antibacterial effects as well as antibiotic resistance-modifying activity. In this study, perillyl alcohol and hydrocinnamic acid were characterized for their antimicrobial action against Escherichia coli. Furthermore, dual and triple combinations of these molecules with the antibiotics chloramphenicol and amoxicillin were investigated for the first time. Perillyl alcohol had a minimum inhibitory concentration (MIC) of 256 µg/mL and a minimum bactericidal concentration (MBC) of 512 µg/mL. Hydrocinnamic acid had a MIC of 2048 µg/mL and an MBC > 2048 µg/mL. Checkerboard and time-kill assays demonstrated synergism or additive effects for the dual combinations chloramphenicol/perillyl alcohol, chloramphenicol/hydrocinnamic acid, and amoxicillin/hydrocinnamic acid at low concentrations of both molecules. Combenefit analysis showed synergism for various concentrations of amoxicillin with each phytochemical. Combinations of chloramphenicol with perillyl alcohol and hydrocinnamic acid revealed synergism mainly at low concentrations of antibiotics (up to 2 μg/mL of chloramphenicol with perillyl alcohol; 0.5 μg/mL of chloramphenicol with hydrocinnamic acid). The results highlight the potential of combinatorial therapies for microbial growth control, where phytochemicals can play an important role as potentiators or resistance-modifying agents.

Impact of atrial fibrillation on in-hospital outcomes of coronary artery bypass graft surgery: an analysis by propensity score matching

Background/Introduction

Many patients referred for coronary artery bypass graft (CABG) surgery have persistent or permanent atrial fibrillation (AF). Despite the significant occurrence, the impact of this arrythmia on surgical outcomes remains uncertain.

Purpose

To assess the impact of persistent or permanent AF on post-CABG in-hospital outcomes.

Methods

A cohort of 3,124 patients undergoing to isolated CABG between 2010 and 2020 was evaluated. A propensity score pairing was applied, considering persistent or permanent AF as a dependent variable and another 19 baseline characteristics as independent variables in the regression model used to build the propensity score. Pairing was performed at a ratio of 3:1 – Group 1: 324 patients without persistent or permanent AF; Group 2: 108 patients with the documented diagnosis of persistent or permanent AF. The statistical plan also included normality analyses, descriptive and univariate analyses, binary logistic regression, ROC curves and DeLong test to compare de curves. The significance level adopted was 5%. The analyses were performed by the programming language Python.

Results

None of the baseline characteristics evaluated showed a significant difference between the groups, including the EuroScore II (Group 1: 1.54±1.45 vs Group 2: 1.49±1.59; p=0.990). Likewise, none of the analysed surgical characteristics showed a significant difference, indicating a very approximate pattern of complexity of the surgeries. The absence of differences demonstrated a high degree of homogeneity between the groups. The use of pairing by propensity score aimed to form two extremely similar study groups, which differed only in relation to the diagnosis of the arrhythmia under study. Among the outcomes evaluated, AMI (1.5 vs 6.5; p=0.013), MACCE (7.1% vs 14.8%; p=0.015) and death (1.5% vs 6.5%; p=0.013) had significantly higher incidences in Group 2, formed by patients with persistent or permanent AF. From the multivariate analysis, it can be identified that permanent AF was an independent risk predictor for the occurrence of in-hospital death (OR: 5.009; 95% CI 1.433–17.507; p=0.012). Finally, it was also possible to verify that the association of EuroScore II with persistent or permanent AF showed higher predictive accuracy than EuroScore II alone (ESII+FA = AUC 0.852 vs ESII alone = AUC 0.775, p&lt;0,05).

Conclusion(s)

Patients with persistent or permanent AF had significantly higher incidences of AMI, MACCE and in-hospital death. Persistent or permanent AF was characterized as an independent predictor for the occurrence of death and the association with the EuroScore II resulted in a 9.9% increase in the predictive accuracy of the surgical risk score.

Funding Acknowledgement

Type of funding sources: None.

Psychiatric intervention on patients recovering from hospitalization due to Covid-19

Introduction

According to recent reports Covid-19 patients may exhibit psychiatric co-morbidities that cause dysfunction, loss of autonomy and emotional suffering even after the physical illness is treated. Considering the high impact Covid-19 may have on mental health, we have created a psychiatric consultation dedicated to the study, observation and support of patients that developed mental illness after being hospitalized due to Covid-19.

Objectives

We aim at 1) describe the profile of patients that developed psychiatric comorbidities following a hospitalization due to Covid-19 and 2) recognize and treat early psychiatric symptoms in Covid-19 patients.

Methods

Based on what was described in other epidemic crisis, we established a semi-structured interview to evaluate several dimensions of the patients’ life that may have been affected by Covid-19 and that may impact on mental health. The interview included the Depression, Anxiety and Stress Scale (DASS-21), the Impact of Event Scale – Revised (IES-R) and the Insomnia Severity Index (ISI). Each patient was observed multiple times over several months. Our evaluation was done in parallel with consultations in Internal Medicine.

Results

Most patients complained of symptoms directly related with the infection of SARS-CoV-2, namely fatigue, short breath and reduced tolerance to efforts. Importantly, many patients also reported de novo or aggravation of anxiety, stress, depression, sleep disturbances and grief often associated with feelings of existential emptiness and lack of purpose.

Conclusions

Hospitalization due to Covid-19 has a high impact on mental health, raising important questions on purpose and emptiness. An early psychiatric intervention is highly recommended.

Disclosure

No significant relationships.

Bulimia nervosa and borderline personality disorder - case report and literature review

Introduction

Bulimia Nervosa (BN) is a debilitating eating disorder characterized by binging and purging episodes generally accompanied by excessive concern with body weight and shape as well as body image disturbance. BN and Borderline Personality Disorder (BPD) may co-occur. In fact, studies estimate that one quarter to one third of patients with BN also meet criteria for BPD. However not much is known about the relationship between these two diseases. Nevertheless, the high comorbidity rate might not be surprising as both BN and BPD may share interacting aetiologies and common core symptoms such as impulsivity and emotional instability. So far, only very little is known about the clinical presentation of patients with both BN and BPD and their response to treatment.

Objectives

Literature review on BN and comorbid BPD. An illustrative clinical case is presented.

Methods

Case report and non-systematic review of the literature - sources obtained through search on Pubmed.gov database.

Results

Female, 19-year-old, student, lived with her mother and stepfather. Developed a poor relationship with her body image due to dental problems during high school. The patient started to binge eat, exhibit compensatory behaviors, restrictive eating pattern, body dissatisfaction and emotional instability while maintaining a normal BMI. Over the last year, she started a self-destructive behavior with slight improvement of BN symptoms.

Conclusions

Special attention should be given to patients suffering from BN and comorbid BPD as they present greater risk of recurrent suicide attempts and non-suicidal self-injury, as well as lower rates of remission. Early interventions that target impulsivity and problematic eating behavior may mitigate risk of future borderline personality features.

Disclosure

No significant relationships.

Impact of Covid-19 on mental health of Portuguese health professionals – longitudinal study, phase I

Introduction

The Covid-19 pandemic brought enormous challenges for health professionals. As in past epidemics, the uncertainty, danger and fear of contamination and an excessive load of work under dramatic conditions may contribute to aggravate the mental health of health professionals.

Objectives

Explore how the Covid-19 crisis impacted the mental health of healthcare workers and how their mental status relates with perspectives on the recent past and near future.

Methods

A longitudinal study will be applied in two phases, Q1 and Q2, one year apart, to evaluate depression, anxiety and post-traumatic stress among health professionals from a healthcare center in Portugal. Phase Q1 is concluded and comprised the Depression, Anxiety and Stress Scale (DASS-21), the Impact of Event Scale – Revised (IES-R) and a questionnaire about the past and the future.

Results

The IES-R scale revealed that nurses are at a higher risk of developing post-traumatic stress disorder (PTSD) than other professionals. The levels of depression and anxiety in the DASS-21 show no significant differences. Interestingly, professionals who worked almost exclusively at inpatient wards show higher levels of depression, anxiety and stress than those who worked at several hospital units (emergency, inpatient and outpatient units). A positive correlation was found between depression and anxiety and negative perspectives about the past and the future.

Conclusions

Covid-19 posed a terrible challenge for health professionals. Its impact on the mental health of healthcare workers may be significant even after the pandemic is under control.

Disclosure

No significant relationships.

Biofilm formation under high shear stress increases resilience to chemical and mechanical challenges

The effect that the hydrodynamic conditions under which biofilms are formed has on their persistence is still unknown. This study assessed the behaviour of Pseudomonas fluorescens biofilms, formed on stainless steel under different shear stress (τw) conditions (1, 2 and 4 Pa), to chemical (benzalkonium chloride - BAC, glutaraldehyde - GLUT and sodium hypochlorite - SHC) and mechanical (20 Pa) treatments (alone and combined). The biofilms formed under different τw  showed different structural characteristics. Those formed under a higher τw were invariably more tolerant to chemical and mechanical stresses. SHC was the biocide which caused the highest biofilm killing and removal, followed by BAC. The sequential exposure to biocides and mechanical stress was found to be insufficient for effective biofilm control. A basal layer containing biofilm cells mostly in a viable state remained on the surface of the cylinders, particularly for the 2 and 4 Pa-generated biofilms.

Biofilms in Diabetic Foot Ulcers: Impact, Risk Factors and Control Strategies

Diabetic foot ulcers (DFUs) are a serious complication from diabetes mellitus, with a huge economic, social and psychological impact on the patients' life. One of the main reasons why DFUs are so difficult to heal is related to the presence of biofilms. Biofilms promote wound inflammation and a remarkable lack of response to host defences/treatment options, which can lead to disease progression and chronicity. In fact, appropriate treatment for the elimination of these microbial communities can prevent the disease evolution and, in some cases, even avoid more serious outcomes, such as amputation or death. However, the detection of biofilm-associated DFUs is difficult due to the lack of methods for diagnostics in clinical settings. In this review, the current knowledge on the involvement of biofilms in DFUs is discussed, as well as how the surrounding environment influences biofilm formation and regulation, along with its clinical implications. A special focus is also given to biofilm-associated DFU diagnosis and therapeutic strategies. An overview on promising alternative therapeutics is provided and an algorithm considering biofilm detection and treatment is proposed.

Release-Recapture Test of Dispersal and Survival of Sterile Males of Ceratitis capitata (Diptera: Tephritidae)

The sterile insect technique is used around the world to suppress or eradicate populations of Ceratitis capitata (Wiedemann) with successful results. It consists of inundative releases of sterile insects into a wide area to reduce reproduction in a field population of the same species. It is necessary to know the dispersion of the sterile males in the field in order to define the maximum distance between the release points that ensures the distribution of the sterile flies in the entire target area. The release methods may vary depending on the area to be covered and the resources available. Manual ground release requires less technology. The aim of this research was to estimate the ability of sterile males to survive and disperse in the field, in the two main areas of citrus production in Uruguay. A release of 20,000 sterile males of C. capitata TslV8 (-inv D53) was performed at the central point of each area defined for the trials. Around these points, a network of 54 Jackson traps baited with trimedlure was installed forming five concentric rings, which were placed on days 1, 3, 5, and 7 after the release and were removed at 24 h in all cases. The emergence rate, flight ability, dispersion, and longevity were estimated. The standard distances obtained by the regression models were 127 m and 131 m for Salto and San José respectively. In Salto, the traps had catches until the eighth day, and in San José, there were no catches after the sixth day.

Pregnancy outcomes in women with mechanical heart valves

Background

Mechanical heart valves (MHV) and their absolute need for adequate anticoagulation poses a challenge for pregnancy, either due to warfarin fetotoxicity or an increased risk of maternal thromboembolism. This represents a unique patient (P) group where data is scarce and maternal and fetal risks and benefits must be carefully weighed.

Purpose

To assess maternal and perinatal outcomes in women with MHV on different anticoagulant regimens and compare them with patients with other types of valvular heart disease (VHD).

Methods

A retrospective analysis of 131 pregnancies in 83 women with VHD (mean age 26.5±5.6 years) was carried out in a tertiary referral centre from 2000 to 2019. 92 pregnancies with VHD, including 11 with biological prosthetic valves, and 39 pregnancies in 22 P with MHV were identified. The main outcome measures were major maternal complications and perinatal outcome.

Results

MHV implanted were in mitral position (89.7%), aortic (2.6%), or both (7.7%). History of rheumatic heart disease was identified in 16 P (72.7%) and a congenital etiology was present in 2 P (9.1%). 9 P (40.9%) were on warfarine and 13 P (59.1%) on acenocumarol. Regarding anticoagulation strategy, 21 P (65.6%) remained on oral anticoagulation and 10 P (31.3%) had been switched to some form of heparin during part or the entire pregnancy. Mechanical valve thrombosis complicated pregnancy in 4 patients (10.2%), all cases on heparin, and resulted in maternal death in 1 P. MHV P had more hemorrhagic complications (15.4 vs 2.2%, p=0.004) requiring transfusion or surgical revision. MHV P tended to experience more NHYA class worsening demanding initiation or intensification of cardiac medication (17.9 vs 5.4%, p=0.023). Also in the MHV group there was a higher incidence of miscarriage (46.2 vs 12.0%, p≤0.0005), comprising spontaneous abortion (31.6 vs 7.6%, p&lt;0.0005) and fetal malformations (18.4 vs 5.4%, p=0.028), including warfarin embryopathy (10.3 vs 1.1%, p=0.012). The live birth rate was higher in women on heparin compared with those on warfarin (85.9 vs 79.2%, p=0.002). The presence of multivalve disease (p=0.04), mechanical protheses (p&lt;0.001), ACO (p&lt;0.001) and previous impaired LVEF (p=0.02) were related to miscarriage. In multivariate analysis, ACO was the unique independent predictor of unsuccessful pregnancy (p=0.01). Only 29% of the patients with an MHV had a pregnancy free of serious adverse events compared with other types of VHD (81.5%, p&lt;0.0005).

Conclusions

MHV remains a challenging condition for pregnancy with only 29% chance of experiencing an uncomplicated pregnancy with a live birth. The increased morbimortality warrant extensive prepregnancy counseling with prosthesis type discussion,centralization of care and further larger studies to come up with evidence-based recommendations.

Funding Acknowledgement

Type of funding source: None

NSAIDs as a Drug Repurposing Strategy for Biofilm Control

Persistent infections, usually associated with biofilm-producing bacteria, are challenging for both medical and scientific communities. The potential interest in drug repurposing for biofilm control is growing due to both disinvestment in antibiotic R&D and reduced efficacy of the available panel of antibiotics. In the present study, the antibacterial and antibiofilm activities of four non-steroidal anti-inflammatory drugs (NSAIDs), piroxicam (PXC), diclofenac sodium (DCF), acetylsalicylic acid (ASA) and naproxen sodium (NPX) were evaluated against Escherichia coli and Staphylococcus aureus. The minimum inhibitory/bactericidal concentrations (MICs and MBCs) and the dose–response curves from exposure to the selected NSAIDs were determined. MICs were found for PXC (800 μg/mL) and ASA (1750 μg/mL) against E. coli, and for DCF (2000 μg/mL) and ASA (2000 μg/mL) against S. aureus. No MBCs were found (>2000 μg/mL). The potential of NSAIDs to eradicate preformed biofilms was characterized in terms of biofilm mass, metabolic activity and cell culturability. Additionally, the NSAIDs were tested in combination with kanamycin (KAN) and tetracycline (TET). ASA, DCF and PXC promoted significant reductions in metabolic activity and culturability. However, only PXC promoted biofilm mass removal. Additive interactions were obtained for most of the combinations between NSAIDs and KAN or TET. In general, NSAIDs appear to be a promising strategy to control biofilms as they demonstrated to be more effective than conventional antibiotics.

Indirect evaluation of pit and fissure sealants: A 3D-based method validation

Background

Material and Methods

Results

Conclusions

Mechanical behavior of implant assisted removable partial denture for Kennedy class II

Background

This study evaluated the mechanical response of a removable partial denture (RPD) in Kennedy Class II according to being associated or not with implants.

Material and Methods

Four RPDs were manufactured for a Kennedy Class II: CRPD - Conventional RPD, RPD+1M, RPD+2M and RPD+12M, respectively, signifying implant assisted RPDs with the implant installed in the first molar, second molar, and in the first and second molars. The finite element method was used to determine the most damaged support tooth under compressive load (300N, 10s) and strain gauge analysis was used to evaluate the microstrain. All groups were submitted to a retentive force analysis (0.5 mm/mm, 100kgf). Microstrain and retentive force data were submitted to One-way ANOVA and the Tukey test, all with α=5%.

Results

High microstrain was observed in the second premolar adjacent to the edentulous space under compression load (p< 0.01). RPD+12M presented lower microstrain, however being similar to RPD+2M. RPD+1M presented a higher mean value of retentive force, but similar to RPD+12M. FEM showed RPD assisted by implants concentrates less stress in the periodontal ligament. The association of two implants was sufficient to decrease the stress generated in the implants. The most stressed region for the o-ring abutment was the threads, and the group with two implants showed the lowest stress concentration.

Conclusions

In cases of Kennedy Class II, the association of RPD with implants in the molar region is a favorable option for patient rehabilitation, reducing the movement of the direct retainer adjacent to the edentulous space, increasing the removal force and decreasing the stress magnitude in the periodontal ligament.

Key words:Removable partial denture, Finite element analysis, Prosthetic dentistry, Implant-assisted RPD, Distal extension RPD considerations.

Improved patient outcomes using the enhanced recovery pathway in breast microsurgical reconstruction: a UK experience

Introduction

The enhanced recovery after surgery (ERAS) pathway is a protocol aimed at optimizing patient care by reducing the physiological alterations caused by surgery, thus reducing recovery time, surgical morbidities and length of stay. This study assessed the impact of ERAS on patients undergoing microsurgical breast reconstruction.

Methods

Patients undergoing microsurgical breast reconstruction over an eight-month period were retrospectively examined. LOS, complication rates and perioperative outcomes were analysed. Results were compared between patients admitted on the traditional recovery after surgery (TRAS) and the ERAS pathways.

Results

One hundred and thirty-eight patients were included. Seventy-two patients were admitted on the TRAS pathway and 66 patients on the ERAS pathway. There was no difference in median LOS (4 days) between the two groups, p = 0.48. We noted a significant reduction in the total number of major complications (ERAS 11%, TRAS 24% p = 0.04) as well as significant differences in time to catheter removal, time to independent mobilisation, total opioid usage and time to removal of PCA, all in favour of the ERAS group. There was a non-significant reduction in return to theatre and readmission rate in the ERAS group (11% versus 21% p = 0.1 and 6% versus 11% p = 0.29 respectively). Obesity and complications were predictors of a prolonged LOS.

Conclusion

The ERAS pathway reduced overall and major complication rates in a tertiary centre using an already streamlined service. Adoption of ERAS pathways to reduce surgical morbidities and improve patient care is encouraged. Further work is required to optimise enhanced recovery in breast microsurgical reconstruction.

Photodynamic inactivation as an emergent strategy against foodborne pathogenic bacteria in planktonic and sessile states

Foodborne microbial diseases are still considered a growing public health problem worldwide despite the global continuous efforts to ensure food safety. The traditional chemical and thermal-based procedures applied for microbial growth control in the food industry can change the food matrix and lead to antimicrobial resistance. Moreover, currently applied disinfectants have limited efficiency against biofilms. Therefore, antimicrobial photodynamic therapy (aPDT) has become a novel alternative for controlling foodborne pathogenic bacteria in both planktonic and sessile states. The use of aPDT in the food sector is attractive as it is less likely to cause antimicrobial resistance and it does not promote undesirable nutritional and sensory changes in the food matrix. In this review, aspects on the antimicrobial photodynamic technology applied against foodborne pathogenic bacteria and studied in recent years are presented. The application of photodynamic inactivation as an antibiofilm strategy is also reviewed.

Antimicrobial Photodynamic Inactivation Mediated by Rose Bengal and Erythrosine Is Effective in the Control of Food-Related Bacteria in Planktonic and Biofilm States

The thermal and chemical-based methods applied for microbial control in the food industry are not always environmentally friendly and may change the nutritional and organoleptic characteristics of the final products. Moreover, the efficacy of sanitizing agents may be reduced when microbial cells are enclosed in biofilms. The objective of this study was to investigate the effect of photodynamic inactivation, using two xanthene dyes (rose bengal and erythrosine) as photosensitizing agents and green LED as a light source, against Staphylococcus aureus, Listeria innocua, Enterococcus hirae and Escherichia coli in both planktonic and biofilm states. Both photosensitizing agents were able to control planktonic cells of all bacteria tested. The treatments altered the physicochemical properties of cells surface and also induced potassium leakage, indicating damage of cell membranes. Although higher concentrations of the photosensitizing agents (ranging from 0.01 to 50.0 μmol/L) were needed to be applied, the culturability of biofilm cells was reduced to undetectable levels. This finding was confirmed by the live/dead staining, where propidium iodide-labeled bacteria numbers reached up to 100%. The overall results demonstrated that photoinactivation by rose bengal and erythrosine may be a powerful candidate for the control of planktonic cells and biofilms in the food sector.

Biofilms and antibiotic susceptibility of multidrug-resistant bacteria from wild animals

Background

The "One Health" concept recognizes that human health and animal health are interdependent and bound to the health of the ecosystem in which they (co)exist. This interconnection favors the transmission of bacteria and other infectious agents as well as the flow of genetic elements containing antibiotic resistance genes. This problem is worsened when pathogenic bacteria have the ability to establish as biofilms. Therefore, it is important to understand the characteristics and behaviour of microorganisms in both planktonic and biofilms states from the most diverse environmental niches to mitigate the emergence and dissemination of resistance.

Methods

The purpose of this work was to assess the antibiotic susceptibility of four bacteria (Acinetobacter spp., Klebsiella pneumoniae, Pseudomonas fluorescens and Shewanella putrefaciens) isolated from wild animals and their ability to form biofilms. The effect of two antibiotics, imipenem (IPM) and ciprofloxacin (CIP), on biofilm removal was also assessed. Screening of resistance genetic determinants was performed by PCR. Biofilm tests were performed by a modified microtiter plate method. Bacterial surface hydrophobicity was determined by sessile drop contact angles.

Results

The susceptibility profile classified the bacteria as multidrug-resistant. Three genes coding for β-lactamases were detected in K. pneumoniae (TEM, SHV, OXA-aer) and one in P. fluorescens (OXA-aer). K. pneumoniae was the microorganism that carried more β-lactamase genes and it was the most proficient biofilm producer, while P. fluorescens demonstrated the highest adhesion ability. Antibiotics at their MIC, 5 × MIC and 10 × MIC were ineffective in total biofilm removal. The highest biomass reductions were found with IPM (54% at 10 × MIC) against K. pneumoniae biofilms and with CIP (40% at 10 × MIC) against P. fluorescens biofilms.

Discussion

The results highlight wildlife as important host reservoirs and vectors for the spread of multidrug-resistant bacteria and genetic determinants of resistance. The ability of these bacteria to form biofilms should increase their persistence.

Cobalt Complex with Thiazole-Based Ligand as New Pseudomonas aeruginosa Quorum Quencher, Biofilm Inhibitor and Virulence Attenuator

Pseudomonas aeruginosa is one of the most dreaded human pathogens, because of its intrinsic resistance to a number of commonly used antibiotics and ability to form sessile communities (biofilms). Innovative treatment strategies are required and that can rely on the attenuation of the pathogenicity and virulence traits. The interruption of the mechanisms of intercellular communication in bacteria (quorum sensing) is one of such promising strategies. A cobalt coordination compound (Co(HL)₂) synthesized from (E)-2-(2-(pyridin-2-ylmethylene)hydrazinyl)-4-(p-tolyl)thiazole (HL) is reported herein for the first time to inhibit P. aeruginosa 3-oxo-C12-HSL-dependent QS system (LasI/LasR system) and underling phenotypes (biofilm formation and virulence factors). Its interactions with a possible target, the transcriptional activator protein complex LasR-3-oxo-C12-HSL, was studied by molecular modeling with the coordination compound ligand having stronger predicted interactions than those of co-crystallized ligand 3-oxo-C12-HSL, as well as known-binder furvina. Transition metal group 9 coordination compounds may be explored in antipathogenic/antibacterial drug design.

Biofilm formation and multidrug-resistant Aeromonas spp. from wild animals

OBJECTIVES

The 'One Health' concept recognises that the health of humans, animals and the environment are interconnected. Therefore, knowledge on the behaviour of micro-organisms from the most diverse environmental niches is important to prevent the emergence and dissemination of antimicrobial resistance. Wild animals are known to carry antimicrobial-resistant micro-organisms with potential public health impact. However, no data are available on the behaviour of sessile bacteria from wild animals, although antimicrobial resistance is amplified in biofilms. This study characterised the ciprofloxacin susceptibility and the adhesion and biofilm formation abilities of 14 distinct Aeromonas spp. (8 Aeromonas salmonicida, 3 Aeromonas eucrenophila, 2 Aeromonas bestiarum and 1 Aeromonas veronii) isolated from wild animals and already characterised as resistant to β-lactam antibiotics.

METHODS

The ciprofloxacin MIC was determined according to CLSI guidelines. A biofilm formation assay was performed by a modified microtitre plate method. Bacterial surface hydrophobicity was assessed by sessile drop contact angle measurement.

RESULTS

All Aeromonas spp. strains were resistant to ciprofloxacin (MICs of 6-60μg/mL) and had hydrophilic surfaces (range 2-37mJ/m²). These strains were able to adhere and form biofilms with distinct magnitudes. Biofilm exposure to 10×MIC of ciprofloxacin only caused low to moderate biofilm removal.

CONCLUSIONS

This study shows that the strains tested are of potential public health concern and emphasises that wild animals are potential reservoirs of multidrug-resistant strains. In fact, Aeromonas spp. are consistently considered opportunistic pathogens. Moreover, bacterial ability to form biofilms increases antimicrobial resistance and the propensity to cause persistent infections.

Prevention, removal and inactivation of Escherichia coli and Staphylococcus aureus biofilms using selected monoterpenes of essential oils

AIMS

The aim of this study was to investigate the antibiofilm potential of five essential oil (EO) components with cyclic (sabinene-SAB, carveol-C1, carvone-C2) and acyclic (citronellol-C3 and citronellal-C4) structures against Escherichia coli and Staphylococcus aureus.

METHODS AND RESULTS

The selected EO components prevented biofilm set-up, with C3 and C4 causing remarkable effects. When applied against pre-established biofilms, they promoted high biomass removal and inactivation of biofilm cells. Moreover, no viable E. coli biofilm cells were detected after exposure to SAB at 5 × MIC and 10 × MIC, and a significant viability decrease was observed for both bacteria with the other EO components. SAB, C3 and C4 caused the most prominent effects apparently due to their octanol-water partition coefficient (Po/w), the number of rotatable bonds (n-ROTB) and the free hydroxyl groups.

CONCLUSIONS

The overall results demonstrated that the selected EO components, particularly SAB, C3 and C4 are of interest as new lead molecules to both prevent biofilm set-up and to control pre-established biofilms of E. coli and S. aureus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The tested EO components exhibited prominent antibiofilm properties against E. coli and S. aureus providing a novel and effective alternative/complementary approach to counteract chronic infections and the transmission of diseases in clinical settings.

Furvina inhibits the 3-oxo-C12-HSL-based quorum sensing system of Pseudomonas aeruginosa and QS-dependent phenotypes

Disruption of cell-cell communication or quorum sensing (QS) is considered a stimulating approach for reducing bacterial pathogenicity and resistance. Although several QS inhibitors (QSIs) have been discovered so far their clinical use remains distant. This problem can be circumvented by searching for QSI among drugs already approved for the treatment of different diseases. In this context, antibiotics have earned special attention. Whereas at high concentrations antibiotics exert a killing effect, at lower concentrations they may act as signaling molecules and as such can modulate gene expression. In this study, the antibiotic furvina was shown to be able to cause inhibition of the 3-oxo-C12-HSL-dependent QS system of Pseudomonas aeruginosa. Furvina interacts with the LasI/LasR system. The data were validated by modeling studies. Furvina can also reduce biofilm formation and decrease the production of QS-controlled virulence factors.

Phytochemical profiling as a solution to palliate disinfectant limitations

The indiscriminate use of biocides for general disinfection has contributed to the increased incidence of antimicrobial tolerant microorganisms. This study aims to assess the potential of seven phytochemicals (tyrosol, caffeic acid, ferulic acid, cinnamaldehyde, coumaric acid, cinnamic acid and eugenol) in the control of planktonic and sessile cells of Staphylococcus aureus and Escherichia coli. Cinnamaldehyde and eugenol showed antimicrobial properties, minimum inhibitory concentrations of 3-5 and 5-12 mM and minimum bactericidal concentrations of 10-12 and 10-14 mM against S. aureus and E. coli, respectively. Cinnamic acid was able to completely control adhered bacteria with effects comparable to peracetic acid and sodium hypochlorite and it was more effective than hydrogen peroxide (all at 10 mM). This phytochemical caused significant changes in bacterial membrane hydrophilicity. The observed effectiveness of phytochemicals makes them interesting alternatives and/or complementary products to commonly used biocidal products. Cinnamic acid is of particular interest for the control of sessile cells.

New Perspectives on the Use of Phytochemicals as an Emergent Strategy to Control Bacterial Infections Including Biofilms

The majority of current infectious diseases are almost untreatable by conventional antibiotic therapy given the advent of multidrug-resistant bacteria. The degree of severity and the persistence of infections are worsened when microorganisms form biofilms. Therefore, efforts are being applied to develop new drugs not as vulnerable as the current ones to bacterial resistance mechanisms, and also able to target bacteria in biofilms. Natural products, especially those obtained from plants, have proven to be outstanding compounds with unique properties, making them perfect candidates for these much-needed therapeutics. This review presents the current knowledge on the potentialities of plant products as antibiotic adjuvants to restore the therapeutic activity of drugs. Further, the difficulties associated with the use of the existing antibiotics in the treatment of biofilm-related infections are described. To counteract the biofilm resistance problems, innovative strategies are suggested based on literature data. Among the proposed strategies, the use of phytochemicals to inhibit or eradicate biofilms is highlighted. An overview on the use of phytochemicals to interfere with bacterial quorum sensing (QS) signaling pathways and underlying phenotypes is provided. The use of phytochemicals as chelating agents and efflux pump inhibitors is also reviewed.

Correlates of children's compliance with moderate-to-vigorous physical activity recommendations: a multilevel analysis

This study aimed to investigate the association between individual and school characteristics associated with the number of school days children comply with moderate-to-vigorous physical activity (MVPA) recommendations. Sample comprises 612 Portuguese children, aged 9-11 years, from 23 schools. Time spent in MVPA was measured by accelerometry, while individual-level correlates were obtained by anthropometry and questionnaires. School-level variables were collected by questionnaire, and accelerometer wear time and season were also considered. Maximum likelihood estimates of model parameters were obtained via a multilevel analysis with children as level-1, and school as level-2. Children who spent more time in sedentary activities and girls were less likely to comply with MVPA/daily. More mature children and those who use active transportation to school were more likely to attain the PA recommendation. Furthermore, greater accelerometer wear time and spring season increased the chance to achieve the recommended MVPA. In terms of school-level correlates, a greater number of available facilities was negatively associated with children MVPA compliance. Given the set of variables, our results showed that individual characteristics seem to be more relevant for children's compliance rates with PA/day than school context variables, which should be taken into account in the implementation of school policies and practices.

Insights on antimicrobial resistance, biofilms and the use of phytochemicals as new antimicrobial agents

Antimicrobial resistance is one of the most serious public health problems. This is of particular concern when bacteria become resistant to various antimicrobial agents simultaneously and when they form biofilms. Consequently, therapeutic options for the treatment of infections have become limited, leading frequently to recurrent infections, treatment failure and increase of morbidity and mortality. Both, persistence and spread of antibiotic resistance, in combination with decreased effectiveness and increased toxicity of current antibiotics have emphasized the urgent need to search alternative sources of antimicrobial substances. Plants are recognized as a source of unexplored chemical structures with high therapeutic potential, including antimicrobial activity against clinically important microorganisms. Additionally, phytochemicals (plant secondary metabolites) present several advantages over synthetic molecules, including green status and different mechanisms of action from antibiotics which could help to overcome the resistance problem. In this study, an overview of the main classes of phytochemicals with antimicrobial properties and their mode of action is presented. A revision about the application of phytochemicals for biofilm prevention and control is also done. Moreover, the use of phytochemicals as scaffolds of new functional molecules to expand the antibiotics pipeline is reviewed.

Antibiotic adjuvants from Buxus sempervirens to promote effective treatment of drug-resistant Staphylococcus aureus biofilms

Plants have been long scrutinized in the quest for new antibiotics, but no strong antibiotic molecule was ever found.

Antibacterial activity and mode of action of selected glucosinolate hydrolysis products against bacterial pathogens

Plants contain numerous components that are important sources of new bioactive molecules with antimicrobial properties. Isothiocyanates (ITCs) are plant secondary metabolites found in cruciferous vegetables that are arising as promising antimicrobial agents in food industry. The aim of this study was to assess the antibacterial activity of two isothiocyanates (ITCs), allylisothiocyanate (AITC) and 2-phenylethylisothiocyanate (PEITC) against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes. The antibacterial mode of action was also characterized by the assessment of different physiological indices: membrane integrity, intracellular potassium release, physicochemical surface properties and surface charge. The minimum inhibitory concentration (MIC) of AITC and PEITC was 100 μg/mL for all bacteria. The minimum bactericidal concentration (MBC) of the ITCs was at least 10 times higher than the MIC. Both AITC and PEITC changed the membrane properties of the bacteria decreasing their surface charge and compromising the integrity of the cytoplasmatic membrane with consequent potassium leakage and propidium iodide uptake. The surface hydrophobicity was also non-specifically altered (E. coli and L. monocytogenes become less hydrophilic; P. aeruginosa and S. aureus become more hydrophilic). This study shows that AITC and PEITC have strong antimicrobial potential against the bacteria tested, through the disruption of the bacterial cell membranes. Moreover, phytochemicals are highlighted as a valuable sustainable source of new bioactive products.

Geostatistics and Geographic Information Systems to Study the Spatial Distribution of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in Peach Fields

The oriental fruit moth, Grapholita molesta (Busck), is the most serious pest in peach, and several insecticide applications are required to reduce crop damage to acceptable levels. Geostatistics and Geographic Information Systems (GIS) are employed to measure the range of spatial correlation of G. molesta in order to define the optimum sampling distance for performing spatial analysis and to determine the current distribution of the pest in peach orchards of southern Uruguay. From 2007 to 2010, 135 pheromone traps per season were installed and georeferenced in peach orchards distributed over 50,000 ha. Male adult captures were recorded weekly from September to April. Structural analysis of the captures was performed, yielding 14 semivariograms for the accumulated captures analyzed by generation and growing season. Two sets of maps were constructed to describe the pest distribution. Nine significant models were obtained in the 14 evaluated periods. The range estimated for the correlation was from 908 to 6884 m. Three hot spots of high population level and some areas with comparatively low populations were constant over the 3-year period, while there is a greater variation in the size of the population in different generations and years in other areas.