[Translated article] Risk factors for infection of tibial plateau fractures

INTRODUCTION

Tibial plateau fractures are injuries prone to postoperative infection, with its reported incidence being higher than that of other fractures, between 5% and 12%. The primary objectives of this study were to quantify the postoperative infection rate of internal fixation of tibial plateau fractures (TPFs) and to identify the risk factors for this.

MATERIAL AND METHODS

Retrospective cohort study including patients who underwent TPF osteosynthesis between 2015 and 2020, in the same center. The study population was divided into two groups, according to the presence or absence of postoperative infection. Demographic variables related to the fracture, surgical parameters, as well as the need for reoperation were collected. Finally, in the case of debridement, the number of positive cultures and the pathogen responsible for the infection were collected, as well as the treatment applied.

RESULTS

One hundred and twenty-four patients were included, with a total of 14 infections (global infection rate of 11.3%). Risk factors for developing infection were open fractures (p=.002), Schatzker V and VI type fractures (p=.002) and the use of external fixation (p<.001). Regarding the surgical variables, only the longest ischemia time (p=.032) was identified as a risk factor. Staphylococcus aureus was the most frequently identified microorganism (43%), followed by Enterobacter cloacae (35.7%).

CONCLUSION

The overall infection rate after osteosynthesis of tibial plateau fractures was 11.3%. Different factors are associated with a higher risk of infection, including diabetes mellitus, open fractures, the use of external fixation, a higher grade in the Schatzker classification or a longer intraoperative ischemia time.

Risk factors for infection of tibial plateau fractures

INTRODUCTION

Tibial plateau fractures are injuries prone to postoperative infection, with its reported incidence being higher than that of other fractures, between 5% and 12%. The primary objectives of this study were to quantify the postoperative infection rate of internal fixation of tibial plateau fractures (TPF) and to identify the risk factors for this.

MATERIAL AND METHODS

Retrospective cohort study including patients who underwent TPF osteosynthesis between 2015 and 2020, in the same center. The study population was divided into two groups, according to the presence or absence of postoperative infection. Demographic variables related to the fracture, surgical parameters, as well as the need for reoperation were collected. Finally, in the case of debridement, the number of positive cultures and the pathogen responsible for the infection were collected, as well as the treatment applied.

RESULTS

One hundred and twenty-four patients were included, with a total of 14 infections (global infection rate of 11.3%). Risk factors for developing infection were open fractures (P=.002), Schatzker V and VI type fractures (P=.002) and the use of external fixation (P<.001). Regarding the surgical variables, only the longest ischemia time (P=.032) was identified as a risk factor. S. aureus was the most frequently identified microorganism (43%), followed by E. cloacae (35.7%).

CONCLUSION

The overall infection rate after osteosynthesis of tibial plateau fractures was 11.3%. Different factors are associated with a higher risk of infection, including diabetes mellitus, open fractures, the use of external fixation, a higher grade in the Schatzker classification or a longer intraoperative ischemia time.

Pilot study on the effectiveness of Reminiscence Therapy on cognition, depressive symptoms, and quality of life in nursing home residents

Aim

This study aimed to assess the effectiveness of the group Reminiscence Therapy (RT) on cognition, depressive symptoms, and quality of life (QOL) in older adults recruited in nursing homes.

Methods

A pilot study with a one-group pretest-posttest design was conducted between September 2017 and March 2018 in five nursing homes from central Portugal. A comprehensive RT program (Core program followed by a Follow-up program) was provided to clinically stable volunteers aged 65 years or more, who did not have severe cognitive impairment.

Results

From the 50 older adults (32 women and 18 men, with mean age of 83.32±7.76, and mean education level of 5.48±4.05) considered eligible to participate in the study, 35 (mean age: 84.17±7.46, mean education level of 6.14±4.49) completed the Core Program and 28 completed the Follow-up Program (mean age: 84.25±7.66, mean education level of 6.18±4.57). Based on the Wilcoxon Test, it was observed that the participants' cognitive performance did not change during the two RT programs. No significant changes were confirmed in relation to depressive symptomatology and QOL.

Conclusion

Although no statistically significant improvements of the older adults' cognitive function, depressive symptomatology, and quality of life were found, the stabilization of such outcomes are relevant from a clinical viewpoint. Further studies are necessary to confirm these findings.

Factors associated with nicotine dependence in a Brazilian rural town

Introduction

Nicotine dependence is a serious global health issue. Over a billion people are estimated to smoke in the world. Withdrawing from smoking contributes significantly to reducing morbimortality. Low income, poor education and smoking from a young age are some of the factors that contribute to the prevalence of tobacco use and to smoking cessation. In Brazil, the National Programme of Tobacco Control is responsible for helping smokers undergoing treatment in primary care units.

Objective

To highlight the association between the results of a nicotine dependence treatment in a Brazilian town, its sociodemographic factors and smoking habits of patients.

Methodology

A cross-sectional study in Santa Cecília, Paraíba, a town in the northeast of Brazil in 2016, relying on data from the medical history of 85 smokers who received treatment in primary care units. Dropout rates and successful results were both considered. Pearson's chi-squared test with 95% significance level was used to assess the association between variables.

Results

51.8% of patients quit smoking while 37.6% abandoned treatment. Around 4.7% of patients smoked fewer cigarettes after treatment and 5.9% did not have a successful result. Among the successful cases, the majority were women (54.4%). Considering smoking habits of those who quit smoking, the following was observed: 29.4% smoked 20 cigarettes per day, 27% were highly dependent on nicotine, 33% spent 20 to 40 years smoking and 18.9% underwent nicotine replacement therapies. Income, marital status and number of cigarettes were variables that showed significant differences (p &lt; 0.001) after treatment.

Conclusions

Smoking cessation after treatment indicates the effectiveness of the programme. The engagement of healthcare professionals is paramount to successfully implement such treatments in primary health care. Further qualitative research is recommended to investigate other Brazilian cities and to assess patient progress individually.

Key messages

This work analyses factors related to nicotine dependence in groups of smokers undergoing treatment developed by the National Programme of Tobacco Control in a Brazilian rural town. Analysing the prevalence of smoking cessation and its related factors among patients undergoing treatment by the National Programme of Tobacco Control in a Brazilian rural town.

Implementation process of social prescribing to improve primary care patients’ health and well-being

Key messages

The social prescribing intervention has been effective in tackling multiple social determinants of health. Intervention evaluation is being key to identify facilitators and opportunities for scale up.

A Study Protocol for Development and Validation of a Clinical Prediction Model for Frailty (ModulEn): a new European Commitment to Tackling Frailty

There is a growing need to implement and evaluate the technological solutions that allow the early detection of age-related frailty and enable assessment of the predictive values of frailty components. The broad use of these solutions may ensure an efficient and sustainable response of health and social care systems to the challenges related to demographic aging. In this paper, we present the protocol of the ModulEn study that aims to develop and validate a predictive model for frailty. For this purpose, the sample composed by older adults aged 65-80 years and recruited from the community will be invited to use an electronic device ACM Kronowise® 2.0. This device allows proactive and continuous monitoring of circadian health, physical activity, and sleep and eating habits. It will be used during a period of seven to ten days. The participants will also be given the questionnaires evaluating the variables of interest, including frailty level, as well as their experience and satisfaction with the device use. Data provided from these two sources will be combined and the relevant associations will be identified. In our view, the implications of this study' findings for clinical practice include the possibility to develop and validate tools for timely prevention of frailty progress. In the long term, the ModulEn may contribute to the critical reduction of frailty burden in Europe.

Influence of self-etch all-in-one adhesives on fissure sealant shear bond strength under contaminated enamel conditions

AIM

To determine the influence of two all-in-one self-etching adhesive systems on shear bond strength of a fissure sealant applied under different enamel surface conditions.

METHODS

A total of 180 bovine enamel specimens were randomly distributed to nine experimental groups, defined by the combination of the sealant application technique (using phosphoric acid, or a self-etching water-based adhesive or a self-etching ethanol and water-based adhesive) and enamel surface conditions (dry enamel, saliva or water contaminated enamel). The specimens were submitted to thermocycling prior to the shear bond strength test.

RESULTS

High shear bond strength mean values were obtained with the classic technique for dry enamel (31.47 MPa), statistically similar values were obtained when the sealant was combined with a self-etching water-based adhesive, in dry enamel (32.36 MPa), and when the sealant was combined with a self-etching water-based adhesive in water contaminated enamel (32.62 MPa). Under enamel salivary contamination, the best results were achieved using a water-based adhesive (24.78 MPa).

CONCLUSIONS

In saliva contaminated enamel, the combination of a sealant with a water-based self-etching adhesive can maintain high and satisfactory values of bond strength.

Selection of an Artificial Diet for Laboratory Rearing of Opogona sacchari (Lepidoptera: Tineidae) (Bojer, 1856)

The banana moth Opogona sacchari (Bojer) (Lepidoptera: Tineidae) is a polyphagous pest that can cause serious damage, in particular to banana crops in southern Brazil. The insect is a quarantine pest in several countries, including Argentina, the main consumer market for bananas from southern Brazil. Little information is available about the biology and ecology of this moth, such as a suitable diet for laboratory rearing. In order to provide support for integrated pest management of the pest, this study furnished data for selecting two diets suitable for continuous laboratory rearing of O. sacchari, one based on dried beans, wheat germ, soy bran, brewer's yeast, and casein and another diet with wheat germ and casein as protein sources. With both diets, the viability of the egg-adult period exceeded 68%, with fertility over 338 eggs per female. A corrected biotic potential analysis gave similar values for the two diets.

[Post-appendectomy intra-abdominal abscesses: six years' experience in a Pediatric Surgery Department]

OBJECTIVES

Post-appendectomy intra-abdominal abscesses are estimated to complicate up to 4.2% of acute non-perforated appendicitis and between 6.7% and 28% acute perforated appendicitis. This study was performed with the aim to review and characterize post-appendectomy intra-abdominal abscesses in our Pediatric Surgery department; to calculate their incidence and to evaluate the efficacy of the treatment modality.

MATERIAL AND METHODS

A retrospective analysis of all patients, under 18 years and with the diagnosis of intra-abdominal abscess post-appendectomy, between January 2010 and December 2015 was performed, taking in account initial surgical approach, type of acute appendicitis, length of hospital stay and the treatment applied. Data were collected by reviewing clinical files.

RESULTS

In a total of 1,340 appendectomies performed, there were 24 intra-abdominal abscesses identified (1.79%). Eight were feminine and sixteen masculine, and mean age was 11.9 years. In 52% of cases the diagnosis was made in the initial admission. Twelve have been submitted to laparoscopic appendectomy and the other 12 to open appendectomy. Of the 24 patients, only 4 needed a surgical re-intervention, which leaves medical treatment an 83.3% success rate.

CONCLUSIONS

TThe incidence of intra-abdominal abscesses post-appendectomy, in the studied population, is what was expected and inferior to what's described in the literature. In our sample, conservative management for intra-abdominal abscesses post-appendectomy was successful in most of the cases, only 4 needing further surgical intervention.

Bladder pain induced by prolonged peripheral alpha 1A adrenoceptor stimulation involves the enhancement of transient receptor potential vanilloid 1 activity and an increase of urothelial adenosine triphosphate release

AIM

Pathophysiological mechanisms of chronic visceral pain (CVP) are unknown. This study explores the association between the sympathetic system and bladder nociceptors activity by testing the effect of a prolonged adrenergic stimulation on transient receptor potential vanilloid 1 (TRPV1) activity and on urothelial adenosine triphosphate (ATP) release.

METHODS

Female Wistar rats received saline, phenylephrine (PHE), PHE + silodosin, PHE + naftopidil or PHE + prazosin. TRPV1 knockout and wild-type mice received saline or PHE. Visceral pain behaviour tests were performed before and after treatment. Cystometry was performed, during saline and capsaicin infusion. Fos immunoreactivity was assessed in L6 spinal cord segment. Human urothelial ATP release induced by mechanical and thermal stimulation was evaluated.

RESULTS

Subcutaneous, but not intrathecal, PHE administration induced pain, which was reversed by silodosin, a selective alpha 1A adrenoceptor antagonist, but not by naftopidil, a relatively selective antagonist for alpha 1D adrenoceptor. Silodosin also reversed PHE-induced bladder hyperactivity and L6 spinal cord Fos expression. Thus, in subsequent experiments, only silodosin was used. Wild-type, but not TRPV1 knockout, mice exhibited phenylephrine-induced pain. Capsaicin induced a greater increase in voiding contractions in PHE-treated rats than in control animals, and silodosin reversed this effect. When treated with PHE, ATP release from human urothelial cells was enhanced either by mechanical stimulation or by lowering the thermal threshold of urothelial TRPV1, which becomes abnormally responsive at body temperature.

CONCLUSION

This study suggests that the activation of peripheral alpha 1A adrenoceptors induces CVP, probably through its interaction with TRPV1 and ATP release.

Serratia liquefaciens Infection of a Previously Excluded Popliteal Artery Aneurysm

Introduction

Popliteal artery aneurysms (PAAs) are rare in the general population, but they account for nearly 70% of peripheral arterial aneurysms. There are several possible surgical approaches including exclusion of the aneurysm and bypass grafting, or endoaneurysmorrhaphy and interposition of a prosthetic conduit. The outcomes following the first approach are favorable, but persistent blood flow in the aneurysm sac has been documented in up to one third of patients in the early post-operative setting. Complications from incompletely excluded aneurysms include aneurysm enlargement, local compression symptoms, and sac rupture. Notably infection of a previously excluded and bypassed PAA is rare. This is the third reported case of PAA infection after exclusion and bypass grafting and the first due to Serratia liquefaciens.

Methods

Relevant medical data were collected from the hospital database.

Results

This case report describes a 54 year old male patient, diagnosed with acute limb ischaemia due to a thrombosed PAA, submitted to emergency surgery with exclusion and venous bypass. A below the knee amputation was necessary 3 months later. Patient follow-up was lost until 7 years following surgical repair, when he was diagnosed with aneurysm sac infection with skin fistulisation. He had recently been diagnosed with alcoholic hepatic cirrhosis Child–Pugh Class B. The patient was successfully treated by aneurysm resection, soft tissue debridement and systemic antibiotics.

Conclusion

PAA infection is a rare complication after exclusion and bypass procedures but should be considered in any patient with evidence of local or systemic infection. When a PAA infection is diagnosed, aneurysmectomy, local debridement, and intravenous antibiotic therapy are recommended. The “gold standard” method of PAA repair remains controversial. PAA excision or endoaneurysmorrhaphy avoids complications from incompletely excluded aneurysms, but is associated with a high risk of neurological damage.

•

Popliteal artery aneurysms (PAAs) are the most common cause of non-traumatic leg amputation.

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Potential complications from PAA exclusion are aneurysm enlargement, local compression symptoms, sac rupture, and infection.

•

Infection of a previously excluded and bypassed popliteal artery aneurysm is exceedingly rare.

•

This is the third case of excluded aneurysm infection, and the first by the Serrate genus.

Metabolomic and Genome-wide Association Studies Reveal Potential Endogenous Biomarkers for OATP1B1

Transporter-mediated drug-drug interactions (DDIs) are a major cause of drug toxicities. Using published genome-wide association studies (GWAS) of the human metabolome, we identified 20 metabolites associated with genetic variants in organic anion transporter, OATP1B1 (P < 5 × 10-8 ). Of these, 12 metabolites were significantly higher in plasma samples from volunteers dosed with the OATP1B1 inhibitor, cyclosporine (CSA) vs. placebo (q-value < 0.2). Conjugated bile acids and fatty acid dicarboxylates were among the metabolites discovered using both GWAS and CSA administration. In vitro studies confirmed tetradecanedioate (TDA) and hexadecanedioate (HDA) were novel substrates of OATP1B1 as well as OAT1 and OAT3. This study highlights the use of multiple datasets for the discovery of endogenous metabolites that represent potential in vivo biomarkers for transporter-mediated DDIs. Future studies are needed to determine whether these metabolites can serve as qualified biomarkers for organic anion transporters. Quantitative relationships between metabolite levels and modulation of transporters should be established.

[Bilateral submandibulectomy for the treatment of drooling in pediatric age: 10 years of experience]

INTRODUCTION

Sialorrhea is a medical problem and can become a social issue, common in children with neurological disabilities. The bilateral submandibulectomy is one of the available treatment options for managing this pathology.

AIM OF THE STUDY

The aim of this study is to evaluate the effectiveness of bilateral submandibulectomy in the management of sialorrhea in children with neurological disabilities through the parents' satisfaction grade.

PATIENTS AND METHODS

We retrospectively analyzed 91 bilateral submandibulectomies for a period of time of 10 years (2004-2015). Data were taken from surgical records and patients files and were informatically processed. The severity grade before and after surgery was evaluated in line with the modified Teacher scale. Parental satisfaction was evaluated by applying a scale graded into five classes, according to the degree of sialorrhea severity in postoperative period.

RESULTS

During the reporting period, 91 children underwent bilateral submandibulectomy in our center. Of these, 7 cases were excluded for lack of data. The average age of the children was 8,9 [± 3,5] years; 58,3% were male. The degree of preoperative sialorrhea severity was, in 52,4% of cases, level 4 (severe drooling), and in 28,6%, level 5 (very severe). The grade of parental satisfaction in postoperative period was ranked, in 73,8% of cases, between 81-100%.

CONCLUSIONS

For children with drooling, a bilateral submandibulectomy emerges as an effective and efficient treatment, leaving parents with an extremely high satisfaction grade.

Is there a role for urokinase-type plasminogen activator inhibitors as maintenance therapy in patients with ovarian cancer?

There is abundant evidence that the urokinase-type plasminogen activator (uPA), its inhibitors PAI-1 and PAI-2 (plasminogen activator inhibitor type-1 and type-2) and its cells surface receptor (uPA-R, CD87) play a fundamental role in tumor invasion and metastasis and are of significant prognostic significance for many tumor types. We performed a systematic Med-line search on uPA, PAI, uPA-R and (epithelial) ovarian cancer (EOC). The majority of malignant EOC specimens show moderate to strong immunostating of tumor and stromal cells. Overexpression of u-PA and PAI-1 can be found in more the 75% of primary ovarian carcinomas, in most metastatic EOC samples and all examined epithelial ovarian cancer cell lines. uPA overexpression in primary specimens was significantly associated with tumor stage, grade, residual disease status after cytoreductive surgery, and poor clinical outcome. This may be explained by increased chemoresistance, a lower resectability and more aggressive tumor biology and tumor dissemination in patients with high uPA and PAI-1. Several therapeutical approaches aimed at inhibiting the uPA/uPAR functions have shown to possess anti-tumor effects in vitro and in animal models. When treating a patient with advanced ovarian cancer it may to be assumed that inhibiting the progression of established (micro) metastases may be more therapeutically relevant than trying to destroy all tumor cells which is not possible in most cases with current systemic treatment modalities. Taking into account the role of uPA and PAI in cell detachment, formation of new stroma, tumor cell reimplantation and metastasis uPA inhibition should be further investigated as maintenance treatment in patients with advanced EOC.

Urinary bladder inflammation induces changes in urothelial nerve growth factor and TRPV1 channels

BACKGROUND AND PURPOSE

The urinary bladder urothelium expresses various receptors and in response to chemical and mechanical stimuli releases mediators, thereby modulating bladder sensory pathways. Transient receptor potential vanilloid 1 (TRPV1) ion channels and nerve growth factor (NGF) in those cells are implicated in this modulatory effect and play a role in sensitizing pain-related afferent pathways during inflammation. In this study, we investigated the interaction between NGF and TRPV1 channels in urothelial cells.

EXPERIMENTAL APPROACH

Urothelial cells from female Sprague-Dawley rat bladders were cultured to quantify membrane expression of TRPV1 channels and capsaicin-induced ATP release in the presence of NGF alone or with TrKA or PI3K inhibitors. Pain scores from rats with cyclophosphamide (CYP)-induced bladder inflammation were assessed after treatment with a TrkA antagonist. Bladders (from control and CYP rats) were collected and analysed for NGF content and TRPV1 channel expression.

KEY RESULTS

Cultured cells responded to NGF with increased TRPV1 channel expression in the cell membrane and increased release of ATP. Both responses were blocked by either a TrkA antagonist or a PI3K inhibitor. Treatment in vivo with the TrkA antagonist alleviated pain symptoms and reduced CYP-induced NGF overexpression in the mucosa. Furthermore, in urothelial cells from animals with bladder inflammation, expression of TRPV1 channels in the membrane was significantly increased.

CONCLUSIONS AND IMPLICATIONS

During bladder inflammation, increased production of NGF in urothelial cells induced increased expression and activity of TRPV1 channels in the cell membrane. This effect was primarily mediated by the PI3K pathway.

Craniofacial features and specific oral characteristics of Down syndrome children

AIM

This article intends to describe the characteristics of Down syndrome children in order to facilitate their management in the dental office.

METHODS

A review of literature was made limited to articles published between 2003 and 2013. The article is based on a literature search in PubMed and the authors' clinical experience with the patient group.

DISCUSSION

Individuals with Down syndrome are clinically characterized by generalized hypotonia, neurological, cardiac and respiratory problems and changes in their stomatognathic system. Almost all these patients have an occlusal disharmony, including anterior open bite, anterior and posterior crossbite, anterior proclination and underdevelopment of the maxilla and the midface. Dental anomalies such as hypodontia, peg-shaped teeth and enamel hypocalcification are also found. The dentomaxillofacial features have clinical implications in speech, nutrition, posture, ventilation and aesthetics, with enormous consequences in growth, development and social integration.

CONCLUSIONS

When planning the dental treatment of patients with Down syndrome, dental practitioners should always consider their general health, in order to achieve a holistic and interdisciplinary approach.

The effect of rearing in different temperature regimes on the reproduction of Anagasta kuehniella (Lepidoptera: Pyralidae)

Eggs of Anagasta kuehniella (Zeller) are widely used in mass rearing of parasitoids, especially Trichogramma spp. and predators in many biological-control programs. The objective of this study was to improve the efficiency of mass rearing of A. kuehniella through determining the optimal temperature conditions for rearing, by assessing the effect of temperature during the developmental stages on the reproduction of A. kuehniella. We evaluated 1) the effect of temperature at which A. kuehniella was kept from egg to adult death, on reproduction; 2) the effect of temperature during the larval and pupal stages on oviposition; and 3) the effect of different temperatures on adults that originated from larvae kept in a constant temperature of 25°C. The results indicated that the optimal temperature range for the development of A. kuehniella is between 20-30°C, as at 30°C there was a marked decrease in viability of the egg and larval stages. The best temperature for maintaining A. kuehniella from egg to adult death is 25°C. Temperatures of 30 and 32°C lead to deformations in genitalia of males, reducing the viability of eggs, and also eggs and females from these temperatures have lower weights. The rearing temperature of immatures affects the egg-laying capacity of adults and the egg viability. The oviposition capacity of adults kept in different temperatures ranging from 18 to 32°C, after being reared in constant temperature (25°C) during the larval stages, was not affected.

Vitamin D insufficiency in Brazilian patients with SLE: prevalence, associated factors, and relationship with activity

The influence of vitamin D on the severity of systemic lupus erythematosus (SLE) has been studied. Our objectives were to determine the prevalence of vitamin D insufficiency in Brazilian lupus patients and its relationship with demographic, clinical, and laboratory variables and to study the relationship between vitamin D insufficiency and disease activity. This is a cross-sectional study of 159 SLE patients. Levels of serum 25-hydroxyvitamin D (25(OH)D) <30 ng/ml were defined as vitamin D insufficiency and <20 ng/ml as deficiency. Data collected included sex, age, ethnicity, postmenopausal status, disease duration, cumulative amount of oral glucocorticoids (GC) in the last six months, duration of GC usage, calcium and vitamin D supplements, photosensitivity, sunscreen usage, sun exposure, diabetes mellitus, creatinine clearance, lifestyle habits, and smoking. Disease activity was measured by the SLE Disease Activity Index 2000 (SLEDAI-2K). Bivariate statistical analysis was performed using the Mann-Whitney test, Spearman's correlation coefficient, Chi-square test, and Fisher's exact test. Multivariate analysis was performed with multiple linear regression. The prevalence of vitamin D insufficiency and deficiency were 37.7% and 8.2%, respectively. Levels of 25(OH) D were not associated with lupus activity score, disease duration, sun exposure, vitamin D supplementation, or use of corticosteroids.

Patulin determination in apples with rotten areas

Patulin is a mycotoxin produced by Penicillium and Aspergillus species, and in particular by P. expansum in apple-rotting fungus. In this work, we evaluated the patulin content in apples with rotten areas of different sizes (with green and/or blue moulds), and we studied the diffusion behaviour of patulin into unspoiled areas of the apples. An analytical procedure based on high-performance liquid chromatography with UV detection was used to analyse 35 apples with rotten areas. Separations were performed on a 250×4.6 mm i.d. C18 analytical column of 5 µm diameter. Acetonitrile/water (5:95) was used as the mobile phase at a flow rate of 1.5 ml/min and the elution was monitored by UV absorption at 275 nm, performed at 40 °C. The detection limit by HPLC-UV detector for pure standard was 6.7 ng/ml and the quantification limit was 0.03 µg/ml. The affected areas represented different percentages of the total weight of the whole apple and ranged from 2.5 to 52.3%. Three apples had patulin concentrations below the limit of detection; the remaining 32 apples had varying patulin levels (from 1.01 to 120.40 mg/kg). To evaluate if the mycotoxin could migrate to the areas not yet affected by rot, we analysed the unspoiled portion of each apple, showing 1.91 µg/kg as the median concentration of patulin and the highest value of 5,020 µg/kg; these results confirmed that patulin could migrate through apple tissue that has not yet been spoiled.

Patulin biodegradation using Pichia ohmeri and Saccharomyces cerevisiae

The effectiveness of Pichia ohmeri and Saccharomyces cerevisiae in the biodegradation of patulin was evaluated in vitro. Patulin is a toxin produced by Penicillium expansum, the predominant fungal contaminant in post-harvest apple. The biodegradation experiment was carried out in culture medium (Yeast Medium broth, YM) and commercial apple juice. These substrates were artificially contaminated with patulin previously produced by P. expansum strain 2 in malt extract broth and purified over a silica gel column. The YM broth was inoculated with P. ohmeri 158 with proved anti-P. expansum activity, whereas the apple juice was inoculated with dried Saccharomyces cerevisiae cells. The residual patulin in contaminated substrates was determined by reversed-phase HPLC. P. ohmeri 158 in YM broth degraded over 83% of the initial 223 µg (8.92 µg/ml) of patulin after incubation at 25 °C for two days under static conditions; after five days of incubation, this percentage was greater than 99%, and patulin levels fell below the limit of detection after 15 days. In the apple juices inoculated with 0.25 g/l of commercial dried S. cerevisiae cells (corresponding 1.8 x 107 cells/ml), 96% of patulin was degraded (initial contamination of 4.5 µg/ml of patulin) after 143 hours of incubation at 25 °C under static conditions. However, 90% degradation occurred when the juice was contaminated with 7.0 µg/ml under the same conditions, indicating that the biodegradation rate is concentrationdependent. The effective biodegradation of patulin using P. ohmeri 158 and S. cerevisiae demonstrates a promising application for innocuous yeast isolated from natural microbiota in the biological control, which can prevent both fruit spoilage and P. expansum mycotoxin contamination.