The development of food-borne and infectious diseases has increased globally at an anomalous rate and is combined with emerging social and economic problems. This highlights the need for new and improved antibacterial agents with novel and different mechanisms of action at regular intervals. Some chemical or artificial food additives are considered harmful if they are used beyond their permissible levels. Today, consumers are demanding alternative, green, safer, and natural food additives to increase the shelf life of food. Essential oils (EOs) are concentrated liquid mixtures of volatile compounds with antioxidant and antibacterial properties that can be used as natural, eco-friendly, renewable, and cost-effective additives. The use of combinations of different EOs and their components is a promising strategy to increase the synergistic and additive effects of EOs in foods. In this article, we review the recent literature on EOs concerning the chemical constituents, extraction methods, antioxidant and antibacterial activities, and their mechanisms of action. Additionally, we discuss the synergistic interaction of different EOs and their components, challenges, and future directions of EOs as natural food preservatives, with special emphasis on shelf life extension and applications in the packaging of food products.

Synergistic Antioxidant and Antibacterial Advantages of Essential Oils for Food Packaging Applications.

Endophytic microbes are microorganisms that colonize the intracellular spaces within the plant tissues without exerting any adverse or pathological effects. Currently, the world population is facing devastating chronic diseases that affect humans. The resistance of pathogens to commercial antibiotics is increasing, thus limiting the therapeutic potential and effectiveness of antibiotics. Consequently, the need to search for novel, affordable and nontoxic natural bioactive compounds from endophytic fungi in developing new drugs with multifunction mechanisms to meet human needs is essential. Fungal endophytes produce invaluable bioactive metabolic compounds beneficial to humans with antimicrobial, anticancer, antidiabetic, anti-inflammatory, antitumor properties, etc. Some of these bioactive compounds include pestacin, taxol, camptothecin, ergoflavin, podophyllotoxin, benzopyran, isopestacin, phloroglucinol, tetrahydroxy-1-methylxanthone, salidroside, borneol, dibenzofurane, methyl peniphenone, lipopeptide, peniphenone etc. Despite the aforementioned importance of endophytic fungal metabolites, less information is available on their exploration and pharmacological importance. Therefore, in this review, we shall elucidate the fungal bioactive metabolites from medicinal plants and their pharmacological potential.

Pharmacological Potential of Fungal Endophytes Associated with Medicinal Plants: A Review

Plants are excellent sources of functionally bioactive compounds and essential nutrients. The phytochemical constituents have enormous potential in treating both plant and human diseases. Parkia timoriana (Yongchak/Zawngtah), one of the most important underutilized plants popularly consumed in Manipur and Mizoram states of Northeastern region of India, is known for its ethnobotanical and ethnomedicinal values. A significant DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)), and Phosphomolybdate scavenging activity corresponding to high antioxidant potentials was shown by the extracts from different edible parts of P. timoriana. P. timoriana extract showed significant antibacterial potential against Bacillus pumilus, Bacillus subtillis, Escherichia coli and Pseudomonas aeruginosa. Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry (GC-MS) analyses of the extracts revealed the functional groups and bioactive compounds present in different edible parts of the plant. Characteristic peaks of phenols, carboxylic acids, alkenes, glycogen, alkyl halides, halogen, aliphatic amines, primary and secondary amines, esters, ether, aromatics, lipids, triglycerides, nitro compounds that had antimicrobial, anti-cancer and anti-inflammatory properties etc. were observed. The GC-MS analysis also revealed the occurrence of 49 bioactive compounds that are known to possess a variety of pharmacological activities. Subsequently, in silico molecular docking studies of the identified bioactive compounds predicted potential anticancer and anti-inflammatory properties. To the best of our knowledge, this is the first-hand report on the bioactive compounds of edible parts of P. timoriana extracts showing antioxidant, antimicrobial and pharmacological significance. This study can lead to the production of new herbal medicines for various diseases employing P. timoriana and perhaps leading to the creation of new medications. 

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GC–MS and molecular docking analyses of phytochemicals from the underutilized plant, Parkia timoriana revealed candidate anti-cancerous and anti-inflammatory agents

Insight into probiotic properties of lactic acid bacterial endosymbionts of Apis mellifera L. derived from the Polish apiary.

Accumulating evidence shows a high prevalence of Clostridium difficile in Southeast Asia associated with a range of clinical presentations. However, severe infections are rarely reported. We investigated C. difficile infection (CDI) across four hospitals in Kuala Lumpur and Kota Bharu, Malaysia. Enzyme immunoassays for glutamate dehydrogenase (GDH) and toxin A or B were performed on diarrheal stool specimens collected from patients in 2015 and 2016. Specimens were also cultured and isolates of C. difficile characterized by PCR ribotyping and detection of toxin genes. In total, 437 specimens were collected and fecal toxin was detected in 3.0%. A further 16.2% of specimens were GDH positive and toxin negative. After culture, toxigenic strains were isolated from 10.3% and nontoxigenic strains from 12.4% of specimens. The most prevalent PCR ribotypes (RTs) were RT 017 (20.0%) and RT 043 (10.0%). The high prevalence of RT 017 and nontoxigenic strains in Malaysia and in neighboring Thailand and Indonesia suggests that they localize to the region of Southeast Asia, with an implication that they may mediate the burden of CDI in the region.

High Prevalence of Toxigenic and Nontoxigenic Clostridium difficile Strains in Malaysia.

Canarium patentinervium leaves are used by the local indigenous people of Malaysia for wound healing. The current study is undertaken to screen the comprehensive antibacterial activity of the leaves and barks extracts, fractions and isolated compounds from this plant. Bioassay guided fractionation was also undertaken to deeply evaluate the antibacterial activity of the water fraction of the leaves extract. This is to provide preliminary scientific evidence to the ethnopharmacology usage of this plant by investigating antibacterial properties of the plant and its isolated constituents. Bio-assay guided fractionation and subsequent isolation of compounds using open column chromatography. The antibacterial activity against gram positive and gram negative ATCC strain and resistant clinical strains were evaluated using microtiter broth dilution method to determine minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill assay. The chemical structure of the isolated compounds from the water fraction of the ethanol extract of leaves was elucidated using Nuclear Magnetic Resonance (NMR). The ethanol extract of the leaves and barks showed antimicrobial activity against all four ATCC and eight clinical isolates. The ethanol extract of the leaves and the corresponding water fraction had good activity against MRSA S. aureus. (MIC: 250 μg/ml) and had bactericidal effect on eight of the clinical strains (MSSA,MRSA, oxacillin-resistant CONS, oxacillin-sensitive CONS, Enterococcus faecalis, Klebsiela species, Kleb pneumoniae ESBL and Candida parapsilosis). Further phytochemical investigation of the water fraction of the crude ethanol extract of leaves afforded compound 7 (hyperin) and compound 8 (cynaroside) that had bactericidal activity against tested bacterial species (MIC 50 μg/ml and 100 μg/ml). The two compounds were isolated from this genus for the first time. These results may provide a rational support for the traditional use of Canarium patentinervium Miq. in infections and wound healing, since the antimicrobial compounds isolated were also present in the leaves extract.

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Antibacterial activities of the extracts, fractions and isolated compounds from Canarium patentinervium Miq. against bacterial clinical isolates.

Clostridium difficile infection (CDI) causes mild to severe diarrhoea and pseudomembranous colitis in patients who had prior antibiotic exposure. Despite CDI being prevalent worldwide, its epidemiological data is scanty in Malaysia. This study aimed to determine the prevalence and incidence of CDI at Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Stool specimens from 147-suspected CDI patients were obtained from 1 November 2011 until 31 October 2012. The presence of C. difficile toxin A and/or B were detected using a commercial immunochromatographic kit (Wampole™ Tox A/B Quik Chek). Surveillance data was collected from patients’ medical records to establish the demographic and clinical characteristics. The overall prevalence and incidence of CDI in UKMMC was 6.1% and 5.2 cases per 10 000 patient-days, respectively. Among nine CDI patients, 77.8% were males and 55.6% were Chinese. CDI was most common in medical wards (88.9%). The median age was 60 years and the median length of hospital stay was 13 days. Majority (88.9%) of CDI patients received antibiotics eight weeks prior to CDI. Penicillin-beta-lactamase inhibitors were the most common antecedent antibiotics. Five (55.6%) CDI patients received acid suppressant medications. The in-hospital mortality rate was 22.2%. In conclusion, the prevalence and incidence of CDI at UKMMC is relatively low and occurs sporadically.

Clostridium difficile infection: clinico-epidemiological perspective.

INTRODUCTION
Mortality of Klebsiella pneumoniae (K. pneumoniae) bacteraemia was reported to be on the rise globally. The 30-day mortality rate of K. pneumoniae bacteraemia ranges from 16% to 55% in Beijing, Shanghai, and Taiwan. However, there is a lack of research on the survival outcomes of K. pneumoniae bacteraemia in Malaysia. The objectives of this study were to determine the poor prognostic factors and predictors of 14-day in-hospital mortality from K. pneumoniae bacteraemia.


METHODS
This was a retrospective cohort study of patients with K. pneumoniae bacteraemia in Hospital Canselor Tuanku Muhriz Universiti Kebangsaan Malaysia (HCTM). We included adult patients with blood cultures positive for K. pneumoniae between 1 January 2016 and 31 December 2019. Those with polymicrobial bacteraemia were excluded. Medical records were reviewed to obtain the sociodemographic data, gender, underlying comorbidities, invasive procedures at presentation, sources of bacteraemia, and whether appropriate empirical and definitive antibiotics was given on time. Data regarding complications of K. pneumoniae bacteraemia, including liver abscess, endopthalmitis, septic shock, Quick Pitt (qPitt) bacteraemia score defined as hypothermia, hypotension, respiratory failure, cardiac arrest, and altered mental status and stay in intensive care unit (ICU) were also recorded. The main outcome measure used was the survival in 14 days. Summary of statistical analysis was done.


RESULTS
A total of 260 patients with K. pneumoniae bacteraemia were included. All patients received appropriate empirical and definitive antibiotics within 24 h of the time that the sample for index blood cultures was obtained. Respiratory infection, septic shock, qPitt bacteraemia score ≥2, solid organ malignancy, stay in ICU, central venous line insertion at presentation, urinary catheterisation at presentation, and in-patient mechanical ventilation were identified as independent predictors of mortality in K. pneumoniae bacteraemia. The rate of complications such as liver abscess, endophthalmitis, ICU admission, and septic shock was not significantly different between survivors and non-survivors. The 14-day in-hospital mortality rate was 12.3%. The median length of hospitalisation was 11 days (IQR 6 - 19) . The predictors of poor prognosis for 14 days in-hospital mortality for K. pneumoniae bacteraemia were as follows: qPitt bacteraemia score ≥2, central venous line insertion, indwelling urinary catheter at presentation, and in-patient mechanical ventilation. Timing from K. pneumoniae bacteraemia event to death among those qPitt bacteraemia scores ≥2 was only for 9 days or less.


CONCLUSIONS
The 14-day in-hospital mortality of patients with K. pneumoniae bacteraemia in our setting was low. The qPitt bacteraemia score ≥2 was the strongest predictor of poor prognosis for 14-day in-hospital mortality in patients with K. pneumoniae bacteraemia. The qPitt bacteraemia score should be proposed to be used as a bedside screening tool for gram negative bacteraemia in our daily clinical practice, which is also useful for predicting mortality in critically ill patients.

The risk factors for complications and survival outcomes of Klebsiella pneumoniae Bacteraemia in Hospital Canselor Tuanku Muhriz Universiti Kebangsaan Malaysia.

R. Ramliza

Papers

Antibacterial activities of the extracts, fractions and isolated compounds from Canarium patentinervium Miq. against bacterial clinical isolates.

Clostridium difficile infection: clinico-epidemiological perspective.

The risk factors for complications and survival outcomes of Klebsiella pneumoniae Bacteraemia in Hospital Canselor Tuanku Muhriz Universiti Kebangsaan Malaysia.