The epidermal mucus of fish contains antimicrobial agents that act as biological defence against disease. This study aims to identify antibacterial activity and protein concentration of epidermal mucus of Barbodes everetti, a Bornean endemic freshwater fish. The epidermal mucus was extracted with 3% acetic acid, 0.85% sodium chloride and crude solvents. The mucus activity against eight strains of human pathogenic bacteria, including Bacillus cereus ATCC 33019, Escherichia coli O157:H7, Listeria monocytogenes ATCC 7644, Pseudomonas aeruginosa ATCC 27853, Salmonella braenderup ATCC BAA 664, Salmonella typhimurium, Staphylococcus aureus ATCC 25933, and Vibrio cholerae, were tested. The acetic acid mucus extract of B. everetti was able to inhibit five strains of bacteria and show no activity toward E. coli O157:H7, B. cereus ATCC 33019 and L. monocytogenes ATCC 7644. Moreover, the highest protein concentration was quantified in crude extract, followed by aqueous and acetic acid extracts. This study provides a preliminary knowledge on the activity of epidermal mucus of B. everetti towards five out of the eight human pathogens tested, therefore it may contain potential sources of novel antibacterial components which could be further extracted for the production of natural antibiotics towards human-related pathogenic bacteria.
The discovery of different antimicrobial agents has revolutionized the treatment against a variety of infections for many decades, but the emergence of antimicrobial resistance require rigorous measures, even amid the coronavirus disease 2019 (COVID-19) pandemic. This retrospective study aimed to examine the consumption of antibiotics in patients with COVID-19 admitted into the five hospitals in the province of Punjab, Pakistan. We collected data on the consumption of antibiotics, classified using the World Health Organization (WHO) AWaRe (Access, Watch, and Reserve), within two months-August and September, 2020, and the corresponding months in 2019. Consumption of antibiotics was presented as daily define dose (DDD) per 100 occupied bed-days. Eight different classes of antibiotics were prescribed to patients with COVID-19 without culture tests being performed, with the prescribing of antibiotics of the Watch category was especially prevalent. The consumption of antibiotics was higher during the COVID-19 pandemic compared to the pre-pandemic period: the consumption of azithromycin increased from 11.5 DDDs per 100 occupied bed-days in 2019 to 17.0 DDDs per 100 occupied bed-days in 2020, while the consumption of ceftriaxone increased from 20.2 DDDs per 100 occupied bed-days in 2019 to 25.1 DDDs per 100 occupied bed-days in 2020. The current study revealed non-evidence-based utilization of antibiotics among patients with COVID-19 admitted into the hospitals in Pakistan. Evidently, the current COVID-19 pandemic is a public health threat of notable dimensions which has compromised the ongoing antimicrobial stewardship program, potentially leading to the emergence of antimicrobial resistance among pathogens.
A number of countries, including developed countries, still have typhoid fever as a major problem resulting in frequent outbreaks. The importance of controlling spread of typhoid fever is well known and necessitates periodic studies to delineate epidemiological relationships. Although phage typing remains to be the preferred conventional method for characterisation of typhoid bacilli, it is of limited use due to prevalence of few predominant phage types in the country like India. Therefore, an effort has been made to assess three molecular methods [Outer Membrane Protein (OMP) Profiling, Random Amplification of Polymorphic DNA (RAPD) and Pulsed Field Gel Electrophoresis (PFGE)] for typing of Salmonella enterica serovar Typhi. 128 Salmonella enterica serovar Typhi isolates were identified using biotyping and serotyping followed by antimicrobial susceptibility testing. These isolates were further subjected to OMP analysis, RAPD and PFGE. PFGE (114 unique clusters) was found to be the most discriminatory method followed by RAPD (94 unique clusters) and OMP profiling (50 unique clusters). Multidrug resistant strains were well discriminated by all three methods used in the study. PFGE still remains the most preferred method for detailed epidemiological investigations. However, random amplification of polymorphic DNA and outer membrane protein profiling can also be considered for molecular discrimination of the isolates in the laboratories lacking high-end facilities.
Lactic acid bacteria is well known for it uses as starter culture in various fermented food, and it functions as a good natural antimicrobial agent. Cincaluk, a Malaysian fermented shrimp product commonly found in traditional dishes is commonly enriched with LAB. Out of 50 colonies from a local cincaluk, 7 strains were successfully isolated and shown to be positive in lactose utilization and catalase tests. The majority of the isolates from cincaluk showed Gram-positive cocci morphology and belonged to the group Staphyloccoccus spp. By using agar disc diffusion method, the anti-bacterial properties of these isolates (namely isolate 1, 2, 3, 4, 5, 6, and 7) moderately inhibited the growth of several pathogenic strains, i.e., Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Bacillus subtilis which were used as indicator bacteria. Other than isolates 1, 2, 3 and 5; the 16S rRNA gene for isolate 6 and 7 were successfully amplified. The 16S rRNA gene fragment from isolate 7 was successfully cloned and sequenced. Based on rRNA sequences, both isolates 6 and 7 belonged to the group Staphylococcus piscifermentans, a rare strain previously reported to be specifically isolated exclusive from fish sources.
Lactic acid bacteria (LAB) are non-pathogenic bacteria that have an important role in human daily life. LAB produce antimicrobial agents, such as bacteriocins, diacetyl and hydrogen peroxide which help to extend the shelf life of food products. In this study, LAB were isolated from selected seafood; threadfin salmon and grass shrimp. Antibacterial activity of LAB extracts against Salmonella typhimurium, Listeria monocytogenes, Bacillus cereus and Escherichia coli were determined using the disc diffusion method. Three strains of LAB were selected for the characterization of antibacterial agents produced by LAB. The parameters such as pH, heat, incubation period and medium, were analyzed in this experiment. Changes in environmental parameters affected the activity of antibacterial agents. The antibacterial agents produced by LAB were generally heat stable and stable in a wide range of pH levels. However, the inhibition activity of LAB was destroyed with a heat treatment of 121°C, and the antibacterial effect was reduced at a pH of 12, which occurs in most strains. The medium containing NaCl enhanced the
antibacterial activity of P1S1 and P3S3 strains against S. typhimurium, L. monocytogenes and E. coli. Moreover, the antibacterial agents exhibited the greatest inhibition activity at incubation times between 24 and 72 h. The antibacterial activity was reduced after an incubation time of 96 h. The characterization of antibacterial agents aids in the improvement of food products safety
There are relatively little data on bacteria with antimicrobial activities from Antarctic, especially from the South Shetland Islands when compared to the other parts of the world. Hence, this project was set to isolate and characterize bacteria that produce anti-microbial compounds from Greenwich Island (one of the South Shetland Islands), Antarctica. A total of 356 strains of bacteria were isolated from Greenwich Island. They were screened for antimicrobial activities against 13 Gram-negative and one Gram-positive indicator food-borne pathogens. Two out of the 356 Antarctic bacterial strains exhibited an antagonistic effect on the indicator strains, Escherichia coli, Salmonella spp., Klebsiella pneumoniae, Enterobacter cloacae, Vibrio parahaemolyticus and Bacillus cereus. The two Antarctic bacterial strains were designated as SS157 and SR13. Biochemical and 16S rDNA analysis indicated that the strain SS157 was closely related to Pseudomonas congelans while the strain SR13 was closely related to Pseudomonas tremae. The anti-microbial compounds produced by the two Antarctic bacteria were not sensitive to temperature and were not degraded by trypsin or pronase indicating that they were likely to be chemical compounds or antibiotics. Antimicrobial compounds from strains SS157 and SR13 were broad spectrum, and targeted both Gram-positive and negative pathogens.
This study was conducted to evaluate antimicrobial properties of ethanolic extracts of the leaves of Nephelium lappaceum, Curcuma longa, Cinnamomun cassia, Durio zibethinus, Vitex trifolia, Amaranthus tricolor, Syzygium samarangense and Manihot esculenta. Antibacterial properties of the extracts were studied against fifteen strains of different gram positive and gram negative pathogenic bacteria, including Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Vibrio para, and Escherichia coli using the agar disk diffusion method. Among the tested extracts, only Amaranthus tricolor exhibited specific inhibition of one of the tested bacteria; Bacillus cereus. Using the microdilution method, its minimum inhibitory concentration (MIC) value was determined to be 20 mg/mL.
White feces syndrome (WFS) is an emerging problem for penaeid shrimp farming industries in SE Asia countries, Thailand, Malaysia, Vietnam, Indonesia, China, and in India. This occurrence of this syndrome is usually first evidenced by the appearance of white fecal strings floating on surface of the shrimp ponds. The gross signs of affected shrimp include the appearance of a whitish hindgut and loose carapace, and it is associated with reduced feeding and growth retardation. To investigate the nature of the white feces syndrome, samples of white feces and shrimp hepatopancreas tissue were collected from Penaeus vannamei in affected farms in Indonesia, and these were examined histologically. Within the white feces, we found densely packed spores of the microsporidian Enterocytozoon hepatopenaei (abbreviated as EHP) and relatively fewer numbers of rod-shaped bacteria. From WFS ponds, hepatopancreas samples form 30 individual shrimp were analyzed by histology and in situ hybridization. The results showed that all of the shrimp examined were infected with EHP accompanied by septic hepatopancreatic necrosis (SHPN). Midgut epithelial cells were also infected and this increased the number of tissue types being affected by EHP. By PCR, EHP was detected in all the samples analyzed from WFS-affected ponds, but not in those sampled from healthy shrimp ponds. To determine the modes of transmission for this parasite, we performed feeding and cohabitation bioassays, the results showed that EHP can be transmitted through per os feeding of EHP-infected hepatopancreas tissue to healthy shrimp and through cohabitation ofinfected and healthy shrimp. In addition, we found the use of Fumagillin-B, an antimicrobial agent, was ineffective in either reducing or eliminating EHP in infected shrimp.
Strobilanthes crispus (S. crispus) is an herbal medicine plant which is native to countries from Madagascar to Indonesia. The plants contained high amount of mineral content and vitamin C, B1 and B2. This plant are used in medicinal and to treat a variety of ailments in the various traditional systems of medicine. Phytochemical investigations have revealed that the plant contain polyphenols, flavonoids, catechins, alkaloids, caffeine, tannins, compounds known to possess multiple health beneficial effects. Preclinical studies have shown that the plant possess antioxidant, free radical scavenging, anticancer, antidiabetic, antimicrobial, wound healing and antiulcerogenic activities. This review presents the comprehensive overview of phytochemical constituents, pharmacological and toxicological properties of S. crispus and to provide preliminary information for future research and for commercial exploitation.
Antibiotic resistance in campylobacter is an emerging global public health problem after MRSA and VRE. Fluoroquinolone and macrolide resistance have been found to be more common in this world leading foodborne pathogen. A total of fifty-six isolates of Campylobacter jejuni obtained from raw vegetables
which are consumed as ulam (salad) in Malaysia, were tested with 12 antibiotics used clinically and
agriculturally. The resistance was determined using the disk diffusion method. Results were determined
by hierarchic numerical methods to cluster strains and antibiotics according to similarity profiles. Fifty
five C. jejuni isolates from different isolation sites were all clustered together into ten groups. This indicates that the commodities (raw salad vegetables/ulam) where the isolates originated might share a similar source of cross-contamination along the production route. All antibiotics tested correlated and there were four groupings reflecting their mode of actions. Generally, C. jejuni isolates were found to be highly resistant to erythromycin (91.1%) and tetracycline (85.7%). Both agents are popular antibiotics used clinically to treat bacterial infections. On the other hand, the C. jejuni isolates showed high percentage (80.4%) of resistance towards enrofloxacin, an extensively used antimicrobial agent in agriculture practices. This study showed that C. jejuni isolates were highly multi-resistance to as many as 10 antibiotics. Therefore, in terms of biosafety, the presence of antibiotic resistance strains in the food chain has raised concerns that the treatment of human infections will be compromised.
Fifty-nine isolates of Salmonella enterica subsp. enterica (S. enterica) isolated from indigenous vegetables, ‘selom’ (Oenanthe stolonifera) associated with 13 different serovars were obtained from Chemistry Department of Malaysia. The isolates encompass the common serovar, Salmonella enterica subsp. enterica serovar Weltevreden (S. Weltevreden) (39%) and Salmonella enterica subsp. enterica serovar Agona (S. Agona) (8.5%). Frequencies of the other 11 Salmonella serovars were ranged from 1.7% to 5.1%. All isolates were characterized by Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR), random amplified polymorphic DNA (RAPD), plasmid profiling and antimicrobial susceptibility testing. The results demonstrated ERIC-PCR, RAPD and composite analysis of both are suitable typing methods for S. enterica by demonstrating good discriminative ability and can be utilize as a rapid approach of comparing S. enterica isolates for epidemiological investigation. From this study, ERIC-PCR is exhibited lower discriminatory power when compare with RAPD. On the other hand, plasmid profiles yielded 32 profiles with molecular size ranging from 1129 bp to 17911 bp. Thirteen antimicrobial agents were included in this study and all isolates showed 100% (59/59) resistant to erythromycin and showed Multiple Antimicrobial Resistance (MAR) indexes ranging from 0.08 to 0.68. Dendrogram generated from antimicrobial resistance profiling exhibited poor discriminatory capability at serovar level. Although poultry still remain as the common reservoir for multidrug resistant (MDR) Salmonella. The isolation of 13 Salmonella serovars from selom that showed high MDR in this study is alarming. These results supported the notion that indigenous vegetable (selom) are gaining more antimicrobial resistance and could be potential health hazards.
Natural preservatives having the great antioxidant and antimicrobial activity have been utilized in the food industry for many years. In the present study, the effect of of two brands of commercial Assam green tea infusion (represented by A and B) and 0.02% BHA/BHT on microbial growth, anti-lipid oxidation and color change were investigated in cooked beef. The green tea concentration has influenced to the results. It was found that A and B at the concentration of 250 mg/mL significantly reduced the population of Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium and E. coli in the cooked beef to an undetectable level within 2 days of storage at 4oC. A and B also exhibited higher anti-lipid oxidation activity compared to 0.02% BHA/BHT, and control. Assam green tea infusions in cooked beef significantly increased ∆ L*
value and decreased ∆ a* and ∆ b* value (p ≤ 0.05). These indicate that Assam green tea infusion might be a potential candidate as a natural preservative for beef and other types of food.
Some vegetable oils contain natural antioxidants such as beta carotene and vitamin E namely alpha tocopherol. The objective of this study was to screening the value of α-tocopherol, β-carotene, antioxidant capacity, antimicrobial activity and toxicological properties of roasted pili nut oil (RPNO) and unroasted pili nut oil (UPNO). The result showed that RPNO contained higher amount of vitamin E and less amount of beta carotene compared to UPNO. RPNO and UPNO scavenged DPPH radicals by 24.66% and 9.52% at concentration of 140 μg/ml. The total phenolic compound (TPC) in UPNO and RPNO were about 19.96 ± 0.52 mg/kg and 12.43 ± 0.69 mg/kg respectively. It was observed that bacteria species exhibited different sensitivities towards RPNO, UPNO, Gentamycin, Ampicillin and Chloramphenicol. Bacillus cereus 14570 was the most sensitive bacterium and all strains of Staphylococcus aureus tested were resistant against both samples RPNO and UPNO. An in vitro toxicological study based on the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) cytotoxicity assay was also performed. In vitro cytotoxicity indicated that both RPNO and UPNO had no effect against HeLa (cervical cancer cell), MCF-7 (breast cancer cell) and HT-29 (human colon adenocarcinoma cell) cell lines tested.
Antibacterial effect of modified sago starch-alginate edible film incorporating lemongrass oil at various concentrations was studied. Edible films were prepared from a mixture of modified sago starch and alginate. Lemongrass oil (0.1 - 0.4%, v/w) and glycerol (0 and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antibacterial activity against food pathogenic bacteria such as Escherichia coli O157:H7, Salmonella Enteritidis and Staphylococcus aureus. The edible film exhibited antibacterial activity against Escherichia coli O157:H7 and Salmonella Enteritidis by using agar diffusion assay method. For films tested against Escherichia coli O157:H7, the zone of inhibition increased significantly (p < 0.05) with addition of lemongrass oil at all levels both in the presence and absence of glycerol. The films also significantly (p < 0.05) inhibited the growth of Salmonella enteritidis only with 0.4% lemongrass oil (in the presence and absence of glycerol). However, the films containing lemongrass oil did not show any inhibition effect on Staphylococcus aureus.
Multi-drug resistant staphylococci including methicillin-resistant Staphylococcus aureus
(MRSA) and Methicillin-resistant Staphylococcus epidermidis (MRSE) are among the emerging
pathogens and have become a threat to both human and animals. Foods of animal origin can
easily be contaminated by these bacteria if handled unhygienically or exposed to contaminated
environmental surfaces. The objective of this study was to investigate the occurrence of MRSA
and MRSE in raw chicken meat sold at wet markets in Kota Bharu, Kelantan, Malaysia. One
hundred fresh raw chicken meat samples were collected from three different wet markets in
Kota Bharu, Kelantan. Routine isolation and identification, selective media (Brilliance MRSA2
agar), antimicrobial sensitivity test (AST), minimum inhibitory concentration test (MIC), and
polymerase chain reaction (PCR) amplification of nucA gene and the resistant gene, mecA
were conducted. Based on bacteriology results and growth on selective media, MRSA and
MRSE were detected in 43% (43/100) of the raw chicken meat samples. Using the PCR assay,
77% (34/43) isolates were positive for nucA gene. The detection of these emerging multidrug
resistant bacteria in chicken meat intended for human consumption implies the potential
contamination of food items by the bacteria which in turn may pose risk to the public health.
A cross-sectional study of 109 patients with Pseudomonas aeruginosa bacteremia from the University of Malaya Medical Centre (UMMC) in the years 2000 and 2001 was conducted to describe epidemiological features, underlying diseases, possible source of infection, early mortality among patients as well as the antibiotic susceptibility pattern of patients' isolates. Further analysis of the 87 patient records that were available revealed that the mean age was 48.5 years (SD ± 25.1). Fifty-two per cent of cases were male and 48% female. Seventy-nine per cent of infections were nosocomially acquired, 33% of bacteremias were polymicrobial, 47% of patients had a continuous bladder drainage catheter (CBD) in situ, 33% had a central venous catheter (CVL) present at the time of bacteremia and 30% were ventilated. Sixty-eight per cent of patients had an underlying immunosuppressed state and 26% had undergone surgery involving general anesthesia in the week prior to isolating P. aeruginosa. Among the 23 patients with early mortality, 61% were on inappropriate antimicrobials. Most of the patients' isolates were sensitive to imipenem (86%), ciprofloxacin (81%), ceftazidime (79%), gentamicin (78%) and cefoperazone (77%). Among the community acquired strains, however, there was 100% sensitivity to imipenem, ceftazidime, cefoperazone and ciprofloxacin.
The objective of this study was to evaluate the antimicrobial potential of methanol, acetone and distilled water stem
bark extracts from Canarium odontophyllum against Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 6633,
Escherichia coli ATCC 25932, Pseudomonas aeruginosa ATCC 27853, Acinetobacter baumannii strain sensitive, Candida
albicans ATCC 64677, Candida glabrata ATCC 90028, Aspergillus niger and Fusarium solani M2781. The extracts from
C. odontophyllum stem bark from 3.125 mg/ml to 25 mg/ml were screened against the tested microorganisms using disc
diffusion method. The Minimum inhibitory concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the
extracts against susceptible organisms were determined using microbroth dilution method and streak-plate technique,
respectively. From the antibacterial screening assay, the growth of S. aureus, B. cereus and A. baumannii were inhibited
by methanol extract whereas the acetone extract was capable of inhibiting all the tested microorganisms except E.coli,
F. solani and A. niger. The lowest MIC value for methanol extract was against A. baumannii (0.195 mg/ml) whereas
its MBC value was twice its MIC value (0.391 mg/ml), indicating that methanol extract was bacteriostatic against A.
baumannii. While for acetone extract, S. aureus showed bactericidal effect with equal MIC and MBC values at 0.195 mg/
ml. In conclusion, stem bark of C. odontophyllum has the potential to be the source of antibacterial agent and can be
exploited as an alternative phytoantimicrobial.
A Burkholderia cenocepacia infection usually leads to reduced survival and fatal cepacia syndrome in cystic fibrosis patients. The identification of B. cenocepacia essential genes for in vivo survival is key to designing new anti-infectives therapies. We used the Transposon-Directed Insertion Sequencing (TraDIS) approach to identify genes required for B. cenocepacia survival in the model infection host, Caenorhabditis elegans. A B. cenocepacia J2315 transposon pool of ∼500,000 mutants was used to infect C. elegans. We identified 178 genes as crucial for B. cenocepacia survival in the infected nematode. The majority of these genes code for proteins of unknown function, many of which are encoded by the genomic island BcenGI13, while other gene products are involved in nutrient acquisition, general stress responses and LPS O-antigen biosynthesis. Deletion of the glycosyltransferase gene wbxB and a histone-like nucleoid structuring (H-NS) protein-encoding gene (BCAL0154) reduced bacterial accumulation and attenuated virulence in C. elegans. Further analysis using quantitative RT-PCR indicated that BCAL0154 modulates B. cenocepacia pathogenesis via transcriptional regulation of motility-associated genes including fliC, fliG, flhD, and cheB1. This screen has successfully identified genes required for B. cenocepacia survival within the host-associated environment, many of which are potential targets for developing new antimicrobials.
Antimicrobial coated films were produced by an innovative method that allowed surface modification of commercial low-density polyethylene films so that well-defined antimicrobial surfaces could be prepared. A Pluronic™ surfactant and a polystyrene-polyethylene oxide block copolymer were employed to develop modified materials. The Pluronic™ surfactant provided a more readily functionalised film surface, while block copolymer provided a reactive interface which was important in providing a route to silver nanoparticles that were well adhered to the surface. Antimicrobial films containing silver were manufactured using a spray coater and the amount of silver used for coating purposes varied by the concentration of the silver precursor (silver nitrate) or the number of silver coatings applied. Potential antimicrobial activity of manufactured silver-coated low-density polyethylene films was tested against Pseudomonas fluorescens, Staphylococcus aureus and microflora isolated from raw chicken. The microbiological and physicochemical quality of chicken breast fillets wrapped with silver-coated low-density polyethylene films followed by vacuum skin packaging was also assessed during storage. Antimicrobial activity of developed silver-coated low-density polyethylene films was dependent ( p
Silver nanoparticles (AgNPs) used in this study were synthesized using pu-erh tea leaves extract with particle size of 4.06 nm. The antibacterial activity of green synthesized AgNPs against a diverse range of Gram-negative foodborne pathogens was determined using disk diffusion method, resazurin microtitre-plate assay (minimum inhibitory concentration, MIC), and minimum bactericidal concentration test (MBC). The MIC and MBC of AgNPs against Escherichia coli, Klebsiella pneumoniae, Salmonella Typhimurium, and Salmonella Enteritidis were 7.8, 3.9, 3.9, 3.9 and 7.8, 3.9, 7.8, 3.9 μg/mL, respectively. Time-kill curves were used to evaluate the concentration between MIC and bactericidal activity of AgNPs at concentrations ranging from 0×MIC to 8×MIC. The killing activity of AgNPs was fast acting against all the Gram-negative bacteria tested; the reduction in the number of CFU mL-1 was >3 Log10 units (99.9%) in 1-2 h. This study indicates that AgNPs exhibit a strong antimicrobial activity and thus might be developed as a new type of antimicrobial agents for the treatment of bacterial infection including multidrug resistant bacterial infection.