Catalase Test Research Articles

A novel combinatorial approach for the Identification of Cutibacterium namnetense and Cutibacterium modestum from Facial Acne Samples

Background: Cutibacterium spp. is one of the most understudied bacteria and this is owed to its slow growing nature and its stringent requirement for anoxic conditions. To date, shortgun metagenomic sequencing and MALDI-TOF MS are widely used for species detection but, the latter is not able to distinguish C. acnes from C. modestum and C. namnetense. Our study has innovatively combined colony morphology, biochemical assays and16s rRNA gene sequencing to identify C. acnes as well as the underreported C. namnetense and C. modestum from facial clinical acne samples.Methods: The clinical samples were obtained using a non-invasive method from acne patients at the Dermatology Clinic of Hospital Tuanku Jaafar, Seremban, Malaysia between January 2022 to December 2022. Colonies of Cutibacterium spp. were screened on BHI agar followed by subjecting them to the catalase and indole tests. The isolates were verified as Cutibacterium spp. using API20A and 16s rRNA Sanger gene sequencing.Result: Out of 68 Cutibacterium spp. isolates, 3 were identified as C. modestum and 1 as C. namnetense while the rest were C. acnes. All isolates were present as raised, white colonies with 0.03 to 1mm in diameter on BHI agar. 89.71% of these isolates were indole producers. All isolates were identified as C. acnes in API20A but, the 16srRNA gene sequencing revealed 4 isolates as C. modestum and C. namnetense.Conclusion: This study is the first to report the isolation of C. namnetense and C. modestum in clinical facial acne samples from Malaysia and across Asia, employing a modified combination of morphological, biochemical, and 16srRNA gene analyses. This methodical yet straightforward approach serves as a viable alternative in research settings lacking access to advanced techniques like MALDI-TOF and shotgun metagenomic sequencing. Moreover, this conventional isolation approach is valuable in assessing the sensitivity of the isolates to inhibitory agents apart from antibiotics, expanding researchers' abilities to develop potent antibacterial agents required for human health and wellbeing.Keywords: Acne; Clinical Samples; Combinatorial; Identification

Isolation and Characterization of Naga King Chilli Rhizobacteria

Amongst the many landraces of chilli that are cultivated in the North east region of India, the Naga king chilli (Capsicum chinense Jacq.) is one of the best known worldwide and is widely grown in the state of Nagaland.27 rhizospheric bacteria of Naga king chilli was isolated for their characterization and results suggested that the rhizosphere of Naga king chilli is dominated by smooth, round, either orange or milky white, smooth surface, convex with entire margin and translucent bacteria. The rhizosphere was also observed to be dominated by Gram negative bacteria (21 isolates) while, all the isolates were observed to give positive reaction catalase test and gelatine hydrolysis activity with 18 isolates being able to hydrolyse starch.

Soil microorganism biodiversity in pule (Alostonia scholarus L.) and candlenut trees (Aleurites moluccana L.) at Wijaya Kusuma Campus Surabaya

A beautiful and fresh environment is visible with lush trees that illustrate the level of soil fertility and the diversity of microbes in it. Plant growth and development are influenced by the abundance of soil microbes, which reflect soil fertility and soil biological properties. Wijaya Kusuma Campus Surabaya is a campus whose slogan is Keluruhuran Jiwa Berbenah Lingkungan (Keji Beling) as a form of concern for the environment and the desire to create a healthy environment, it is necessary to explore the existence of potential microbes from the roots of trees in the campus environment. The purpose of this study was to determine the number and type of soil microbial isolates isolated from the rhizosphere of pule (Alostonia scholarus L.) and candlenut (Aleurites moluccana L.) trees on the Wijaya Kusuma Campus Surabaya. This research is exploratory descriptive qualitative research. Research methods include microbial isolation in the rhizosphere of pule and candlenut plants, macroscopic and microscopic characterization of microbes, KOH test, and catalase test. Data were analyzed descriptively describing the number and type of isolates. The results of the study concluded that the isolation results from the Pule tree obtained 12 colonies of fungi and the Candlenut tree obtained 6 colonies. The genus found were Aspergillus flavus, Aspergillus niger, Fusarium sp., Penicillium sp. In addition, 27 bacterial colonies were found on the pule tree and 23 bacterial colonies on the candlenut tree, namely the genus Bacillus sp. The isolate results obtained can be used as microbial observation material in biology learning.

Identification of an unusual Streptococcus agalactiae growing on MacConkey Agar and its confirmation by biochemical tests, qPCR and nanopore sequencing

Streptococcus agalactiae belongs to Group B Streptococcus (GBS), an important Gram-positive pathogen attributed to mastitis and elevated somatic cell counts (SCC) in dairy cows, which invariably exhibits complete β-haemolysis on blood agar (BA) / Polymixin Nalidixic acid Blood Agar (PNBA) and fails to grow on MacConkey agar (MCA). The present study conducted in the Advanced Agricultural Laboratories under the Almarai company, Riyadh, KSA, reports the isolation, identification and characterization of β-haemolytic Strepotococcus agalactiae which exhibited lactose fermenting colonies on MCA. Though the colony characteristics on BA/ PNBA were suggestive of Streptococcus, the observation of pink colored colonies on MCA was deemed unusual and was subjected to further confirmatory tests viz., Gram’s staining, Lancefield grouping, catalase, oxidase and CAMP tests. Further, real-time PCR and Oxford nanopore sequencing of the 16S ribosomal RNA gene were performed for molecular characterization. The findings of the study would add to the existing knowledge on cultural characteristics of Streptococcus agalactiae for its presumptive identification. Keywords: Streptococcus agalactiae, MacConkey agar, nanopore sequencing

ANTIBIOGRAM OF PRE-PROCESSED RAW CHICKEN MEAT FROM DIFFERENT SUPERSHOPS OF DHAKA CITY, BANGLADESH

Pathogenic strains of salmonella, S. aureus, S. epidermidis, shigella, enterobacter and citrobacter are serious health threat for human being. Present investigation was conducted to assess the antibiogram of pre-processed raw chicken meat collected from different chain-shops of Dhaka city. Pre-processed chicken meat samples were collected from three different super-shops (S1, S2, and S3) in Dhaka. The Samples are serially diluted to 10-4, and after growth on MSA, MAC, and SS agars, the total counts showed The most growth S2 (360 × 10.4  18.33), (235 × 10.4), (25 × 10.14.4  3.6) followed by S3 (353.3 × 10.4  42.39), (151.67 × 10.4  22.19), 15 × 10-4  3.0) and finally S1 (3.26.67 × 10.4  29.48), (64.5 × 10.4  8.62) (14 × 10.4  5.13) respectively. Salmonella S aureus, S. epidermidis, Shigella, Enterobacter and Citrobacter were identified after a number of morphological and biochemical tests; Gram staining, MIU, KIA, oxidase and catalase tests, and citrate utilization test following aseptic techniques. Six antibiotics; Vancomycin, and five broad spectrum drugs; Streptomycin, Norfloxacin, Novobiocin, Chloramphenicol, and Cefotaxime were used to test the sensitivity or resistance of the organisms. All the pathogens were susceptible to chloramphenicol. Staphylococcusepidermidis were novobiocin-resistant. Citrobacter spp. and Enterobacter spp. were sensitive to all except novobiocin. Staphylococcusepidermidis was susceptible and intermediate to norfloxacin. Staphylococcusaureus was resistant to norfloxacin and novobiocin; intermediate to cefotaxime, and sensitive to the rest. Salmonella spp. was found to be resistant to novobiocin, vancomycin, and streptomycin; intermediate to norfloxacin, but sensitive to chloramphenicol and cefotaxime. Shigella.spp was found to be sensitive to all the antibiotics but resistant to novobiocin and vancomycin. Fecal coliform E. coli was absent showing some degree of sanitation in the chicken, and all the pathogens were found susceptible to at least two antibiotics

Nasal carriage of MRSA among clinically affiliated undergraduate students at the College of Health and Medical Sciences, Haramaya University, Ethiopia

Medical and health science students are among the demographics most at risk from Methicillin-resistant Staphylococcus aureus (MRSA), which is a serious hazard to public health. The main reservoir for MRSA is the nasal cavity, and colonization of this area can raise the risk of infection and transmission in healthcare settings. This study aimed to assess the nasal carriage rate of MRSA among clinically affiliated students at Haramaya University, College of Health and Medicine Sciences, Ethiopia, from July to August 2022. An institution-based cross-sectional study of 250 study participants was conducted using a stratified random sampling methods. The data were collected via structured questionnaires. Nasal swabs were cultured on mannitol salt agar and blood agar at 37 °C for 24 h. Staphylococcus aureus was identified using catalase and coagulase tests. The MRSA was screened using the cefoxitin disk diffusion method on Muller Hinton agar. The data were entered and analyzed by SPSS version 25. Pearson’s chi-square test was performed to predict associations between variables. A p value less than 0.05 was regarded as statistically significant. The nasal carriage rate of S. aureus was 8% (95% CI: 4.6-11.3%). The Nasal carriage rate of MRSA was 4.8% (95% CI: 2.1-7.4%). Overall, 4.8% of all the students were identified as MRSA carriers. MRSA carriage was high among medical students (33.3%). Nose-picking habit (X2 = 16.7, P = 0.001) and dormitory occupancy (X2 = 3.6, P = 0.045) were significantly associated with the MRSA rate. All the MRSA strains were resistant to penicillin and ampicillin. However, all the MRSA strains were susceptible to chloramphenicol and clindamycin. This study revealed that MRSA is a threat due to significant resistance. Nasal carriage is associated with nose picking and dorm occupancy. Encourage practices such as avoiding nose picking and maintaining personal cleanliness. Regular cleaning and disinfection of shared spaces can reduce the presence of MRSA.

Contribution of domestic animals’ feces to the occurrence of diarrhoea among children aged 6–48 months in Sidama region, Ethiopia: a laboratory-based matched case-control study

BackgroundIn developing countries, due to improper management of domestic animals’ exposures, under-five (U5) children have been affected by diarrhoea. However, there is no evidence that shows the presence of diarrhoea-causing...

Occurrence of Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus pseudintermedius colonization among veterinarians in the province of Malaga, Spain.

Staphylococcus pseudintermedius and Staphylococcus aureus are common colonizing pathogens in companion animals. These opportunistic pathogens can cause infections of varying frequency and severity in humans and pets. Studies on Staphylococcus colonization in veterinarians are scarce. This study aimed to investigate the colonization of the nostrils and hands by S. aureus, Staphylococcus epidermidis, and S. pseudintermedius among healthy clinical practice veterinarians in the province of Malaga (Spain), with a particular focus on their potential antibiotic resistance. A request for voluntary participation was extended to professionals from the Official College of Veterinarians of Malaga. Nasal and hand swabs were collected by two trained technicians in January 2024, and all samples were delivered to the laboratory within 24 h. Gram staining, catalase, oxidase, and coagulase tests were performed. The susceptibility of the isolated bacteria to 11 antibiotics was evaluated. A total of 50 clinical practice veterinarians were enrolled in the study, comprising 36 women and 14 men from 31 veterinary clinics across Málaga province. A total of 32% of the nasal samples yielded S. aureus, whereas 64% were found to contain S. epidermidis. In total, 30% of the hand samples yielded S. aureus and 30% yielded S. epidermidis. The participants did not exhibit any strains of S. pseudintermedius in their nasal samples or hands. Two strains (11.1%) of methicillin-resistant S. aureus were isolated from 18 strains isolated from nostrils. Furthermore, a high prevalence of S. aureus strains resistant to ampicillin (94.4%) and amoxicillin (72.2%) was observed. The colonization profiles of veterinary professionals were similar to those observed in the general population. Further research is required among veterinary professionals, companion animals, and their owners to better understand the colonization processes and the pet-human interface within a "One Health" approach.

Potensi Aktivitas Antagonistik Streptomyces dari Rhizosfer Pohon Pule (Alstonia scholaris) sebagai Biokontrol

Pule plant (Alstonia scholaris) is one of the plants that is often chosen for greening purposes and can be used as a medicinal plant. The ability of Pule plant interaction with microbes is shown from its potential as a source of beneficial microbes, both from the phyllosphere, rhizosphere, and endophytes. The tree rhizosphere microbial ecosystem plays an important role in maintaining tree health and has the potential to produce microorganisms with biocontrol activities. This study aims to evaluate the antagonistic activity of Streptomyces sp isolated from the rhizosphere of Pule trees (Alstonia scholaris) on the ability to inhibit pathogenic bacteria. The research method used disc antagonist test to determine the effectiveness of Streptomyces sp. in inhibiting the growth of pathogenic bacteria, macroscopic and microscopic characterization observations to identify isolates, as well as KOH test and catalase test. The test samples were Streptomyces isolates against Bacillus sp., Fusarium sp., and Aspergillus sp. and the data were analyzed descriptively. The results showed that the isolate Streptomyces sp. has the ability to inhibit the growth of Bacillus sp. and Fusarium sp. In biochemical tests revealed that the isolate is a gram-positive bacterium, based on the results of the KOH test showed that Streptomyces sp. is not slimy (+), while the catalase test produced negative (-) showed no bubbles, meaning Streptomyces sp. does not inhibit the growth of Bacillus sp. and Aspergillus sp.

Prevalence and identification of Bacillus species in cellophane, foil, and disposable plastic containers used for food packaging

Background: Foil, cellophane, and disposable plastic containers are commonly employed in food packaging, namely as coatings on food items. Nevertheless, the existence of microbes on the surface and inside the internal composition of these materials gives rise to concerns, as they have the capacity to multiply under ideal circumstances and spread to food items, thereby jeopardizing the safety and quality of the food. Objective: This study aimed at examining the number of microorganisms and identifying specific bacterial species within frequently used food packaging materials like foil, cellophane, and disposable plastic containers. Methods: samples of foil, cellophane, and disposable plastic containers were collected from various popular brands in Iran. The overall bacterial count wضas determined using defibering, flooding, and smear techniques followed by culturing on Tryptone Glucose Extract Agar (TGEA) medium. To identify the bacterial species, various biochemical tests were performed, including fermentation, motility testing, catalase test, oxidase test, and methyl red-Voges Proskauer (MR-VP) test. Results: Bacterial quantity ranged from 0 CFU/g to 8.3 × 103 CFU/g in analyzed samples. All the samples had primary contaminants mainly Bacillaceae family bacteria that could produce spores. Disposable plastic containers had the lowest bacterial count whereas cellophane showed the highest bacterial contamination level. Among Bacillaceae family members Bacillus licheniformis was dominant. Conclusion: The study's findings emphasize the possibility of microbial contamination in food packaging materials, including cellophane. These results indicate that the food packaging industry should adopt a rigorous approach to hazard evaluation and Important Control Points (HACCP) in order to guarantee the microbiological safety and efficacy of packaging materials.

Isolasi Staphylococcus aureus dari swab tangan penjamah makanan di kantin Universitas Mataram

One of the main qualities of food is seen from the biological safety aspect, such as being free from Pathogenic microorganisms. Staphylococcus aureus is a pathogenic bacterium that can contaminate food ingredients come from the skin of food handlers. S. aureus produces enterotoxins that have a poisoning in consumers.The preliminary observationstated that there were still many food handlers in the Mataram University canteen who did not pay attention to hand hygiene and personal sanitation. This study aims to determine the bacterial contamination of S. aureus swabbed from the hands of food handlers in the Mataram University cafetaria. The method was used in this research is descriptive observational. The research consisted of two stages, namely isolation and biochemical identification. The isolation stage resulted 10 culturable bacterial isolates. All bacteria were able to ferment mannitol on Mannitol Salt Then, the biochemical test identification resulted that all isolates had a positive catalase test, a positive slide coagulase test, Gram-positive, and staphylococci cell. The TSIA test resulted A/A or (acid)/(acid) which indicated that all isolates were able to use diverse carbon sources from sucrose, lactose, glucose. Moreover, other test as sulfur, indole and motility tests were negative. Therefore, all isolates in this study are classified as S. aureus. This research is also a promotive and preventive effort for the campus in implementing hygiene and sanitation for food handlers in the cafetaria.

Quality and yield of potato seed tubers as influenced by plant growth promoting rizobacteria

Using chemical fertilizers in agriculture increases production and improves the quality of the product; however, their higher usage globally has brought forth damage to ecosystems. Using biofertilizers is a better strategy to reduce the use of chemical fertilizers and ultimately increase soil fertility. This study aimed to isolate, identify, and characterize bacteria from the soil rhizosphere of medicinal plants (Rumex tuberosus L. and Verbascum sp.) for in vivo screening. Nitrogen fixation, phosphate solubilization, HCN, ammonia levels, Lipase, protease, catalase and siderophore production biochemical tests were also conducted. The two isolates that gave positive results from the biochemical tests were chosen out of 25 for further experiments. Based on 16S rRNA sequencing analysis the isolated organisms were identified as Alcaligenes faecalis Go1 (Accession No. OP001725) and Bacillus subtilis T11 (Accession No. OP218376). The compound fertilizer NPK was used as the positive control for field experiments, while selected stains were individually and in-combination were tested on potato crops as inoculum, over two successive cropping seasons. Plant height, number of tubers per plant, chlorophyll content, and tuber weight all increased for both isolated bacterial strains. The quality of the potato tubers was checked through visual observation for the presence or absence of disease symptoms. The treated tubers exhibited excellent quality, remaining free from any signs of disease, however, the control tubers showed infections with (Streptomyces scabiei, Fusarium sp., F. solani and Erwinia amylovora). The soil analyzed after harvesting both bacteria increased percentages of P, Ca2+, Mg2+, Na+, K+, SO4, total nitrogen content and total organic matter. The findings showed that the tested bacterial isolates could replace the use of chemical fertilizers in the production of potatoes.

Comparison of Urine Specimen with Recto-Vaginal Swab to establish carriage of Group B Streptococcus Colonization in Pregnant Females

Objective: To determine maternal vaginal colonization with Group B Streptococcus using both recto-vaginal swab and mid-stream urine in order to determine which specimen type can give better results. Study Design: Cross-sectional study. Place and Duration of Study: Armed Forces Institute of Pathology, Rawalpindi Pakistan, Department of Gynecology and Obstetrics, Combined Military Hospital and Pak Emirates Military Hospital, Rawalpindi Pakistan, from Jan to Jun 2022. Methodology: Recto-vaginal swabs and mid-stream urine were taken from 194 pregnant women between 36th and 37th weeks of pregnancy. Swabs were inoculated on blood and MacConkey agar while urine specimen was inoculated on blood and CLED agar. All plates were incubated at 37°C in either ambient air or CO₂ incubator. Identification of Group B Streptococcus was made on the basis of colony morphology (β-haemolytic colonies on blood agar), Gram stain, catalase test and confirmation were done by means of latex agglutination tests. Results: In comparison to urine, a Group B Streptococcus carriage rate of 8.2% was detected in recto-vaginal swab. Urine specimen of only 3 patients yielded growth of Group B Streptococcus giving a urine carriage rate of 1.5%. Conclusion: Recto-vaginal swab gives a better insight to the presence of Group B Streptococcus as compared to mid-stream urine.

Exploring Fresh Lettuce (Lactuca sativa) as a Dairy-Free Probiotic Source

Probiotics are living microorganisms that, when given in appropriate amounts, have optimistic effects on body. This study explores the potential of fresh lettuce (Lactuca sativa) leaves as a probiotic source for individuals with dairy allergies. Gram staining and the catalase test were used to identify the bacteria that were recovered from lettuce leaves as gram-positive, catalase-negative strains. The resistance to antibiotics and their capacity to tolerate low pH and bile salt concentrations both essential for surviving the digestive tract were evaluated. The bacteria showed a high tolerance to bile salts and low pH, but they were susceptible to ampicillin, streptomycin, gentamycin, chloramphenicol, and neomycin. Tests for gas production in the presence of glucose revealed no gas production. Molecular techniques such as PCR and 16S rRNA gene sequencing revealed the presence of Enterococcus lactis, Enterococcus durans, Lactobacillus paracasei, and Lactobacillus casei

Characterization and Prevalence of Antibiotic Resistance Staphylococcus aureus in Street Food: A Public Health Concern

Food samples containing Staphylococcus aureus pose a serious health risk. This study aimed to examine the prevalence of S. aureus strains in various food samples sourced from Mailsi and Multan. Many food samples including yogurt, bakery products, and raw and cooked food were examined for S. aureus. The isolated strains were confirmed through Mannitol agar fermentation, catalase, coagulase, and urease tests. Hemolysis on blood agar and biofilm formation were also assessed to determine toxin production. Antibiotic sensitivity testing was conducted using the Kirby Bauer method on MH agar, and multiple antibiotics were tested. Out of all samples, a total of 50 S. aureus strains were obtained, mainly from milk and milk-based products. Yellow colonies on mannitol salt agar confirmed S. aureus presence, with all isolates testing positive for coagulase, catalase, and urease. The presence of hemolysins: beta, gamma, and alpha were revealed by hemolysis assays. Biofilm assay results showed variation among the strains, with some categorized as strong, moderate, or weak biofilm formers. Regarding antibiotic sensitivity, most strains exhibited multidrug resistance, particularly against certain antibiotics. Vancomycin showed varying susceptibility patterns, some strains showed susceptibility and intermediate resistance, whereas only milk samples showed resistance. This study emphasizes the prevalence of MDR S. aureus strains in food samples. The study underscores the significance of antimicrobial stewardship programs and stringent food safety measures in preventing the spread of antibiotic-resistant strains and reducing foodborne illnesses. Further research is needed to explore the mechanisms behind antibiotic resistance and toxin production in S. aureus strains from food samples.

Essai de production de l’acide polylactique (PLA) à partir de la mélasse de canne à sucre en vue d’élaborer les emballages bioplastiques

This work involves the development of a bioplastic replacement for non-degradable plastics in packaging. The objective was to produce polylactic acid (PLA) from sugarcane molasses with locally produced Lactobacillus delbrucckii. Polylactic acid is a biosourced and biodegradable polymer, it can be plasticized. The lactic acid bacteria necessary for the synthesis were isolated and identified as Lactobacillus delbrucckii following their characteristics. The sugar cane molasses used came from the KwiluNgongo sugar mill with a concentration of 410.9 g/L of fermentable sugar. 1L of diluted molasses was fermented with the inoculum of Lactobacillus delbrucckii in a ratio of 10/1. This fermentation produced 98 g of lactic acid after purification (63.6%). Lactic acid was polymerized to polylactic acid (92%), via lactide (78.46%), by ring opening. Lactobacillus delbrucckii colonies were characterized by Gram staining, catalase test, morphology, appearance of the colony and mode of fermentation. The Brix degree, pH, density and fermentable sugar level were determined on the molasses. The polymer obtained had a brittle behavior when heated and its mixture with 5% glycerol gelled more weakly than in the presence of 10% glycerol.

Signaling Molecules in Pseudomonas aeruginosa Response to Antibiotics at Sub-Inhibitory Concentrations

Signaling Molecules are N-acylhomoserine lactones (AHLs) that form the Pseudomonas aeruginosa cell information system which determines gene expressions in a population dependent manner called quorum sensing (QS). Signal molecules, which are chemically varied, control genes expressions to antibiotics resistance, pathogenicity, motility, biofilm development, bioluminescence, secondary metabolite production, and plasmid transfer. This research was aimed to identify the signaling molecules in Pseudomonas aeruginosa response to antibiotics at sub-inhibitory concentrations. One hundred and fifty (150) clinical swab specimens were collected from urinary catheter wound and ear infection of patients and the swabs inoculated using standard microbiology method. The isolates were characterized based on the bacteriological methods such as morphology and biochemical tests. The isolates were further confirmed by species specific PCR by amplification of 16S rRNA and the amplicons were analyzed by gel electrophoresis; and further genomic sequencing was done and blast with NCBI database mining. Disc diffusion method was applied for the antibiotics susceptibility pattern. The isolates cell suspensions were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). The result of the isolation showed 22(59.46%) from wound infections, 12(32.43%) from ear infections and 3(8.11%) from urinary catheter. The isolates were Gram negative, produced β-hemolysis on blood agar and the morphology is small pigmented circular in form. The isolates showed positive result to catalase, oxidase, citrate, nitrate and indole tests. The amplification of 16S rRNA gene region resulted in the band size of 1500bp PCR product and the BLAST analysis gave 99% similarity. The resistant antibiotics susceptibility showed that Pseudomonas aeruginosa is multidrug resistant bacteria. The GC-MS results obtained from urinary catheter isolates showed four (4) signaling molecules such as N-Octanoyl-L-homoserine Lactone, N-Decanoyl-DL-Homoserine Lactone, N-Dodecanoyl-DL-Homoserine Lactone and N-Tetradecanoyl-L-Homoserine Lactone. Three (3) signaling molecules such as N-Octanoyl-L-homoserine Lactone, N-Decanoyl-DL-Homoserine Lactone and N-Tetradecanoyl-L-Homoserine Lactone were obtained from wound isolates. N-Tetradecanoyl-L-Homoserine Lactone was the only signaling molecule obtained from ear isolates. Further research should be done to develop rapid tests that could be possible to detect acyl homoserine specific to Pseudomonsa aeruginosa present to human samples and deliver results in real time. Signaling molecules inhibitors (SMI) are possible potential therapeutics that could produce the subsequent class of antibacterial drugs. The fundamental role of each signal molecule in the production of biofilms and virulent factors should also be investigated, as well as whether Pseudomonas aeruginosa needs one or more signaling molecules to form quorum sensing. Identification of the signals molecules (AHLs) of P. aeruginosa and developing signaling molecules inhibitors (SMI) can have an important prognostic, diagnostic and therapeutic value in human medicine for the treatment of P. aeruginosa infections.

Preserving Tradition and Promoting Innovation: “Quesillo,” Artisanal Cheese from Oaxaca, Mexico

The quesillo is a traditional food originally produced in the state of Oaxaca, Mexico, is fresh, spun paste or strands, made with raw milk and has unique sensory attributes due to its extensive native microbiota, mainly lactic acid bacteria, which are fermenting microorganisms, safe, are used in the fermentation and preservation of food helping to improve flavor, aroma, and texture. They are part of the natural microbiota of raw milk and its derivatives, mainly traditional cheeses, where the greatest diversity and heterogeneity is found. The objective of this study was to microbiologically identify lactic acid bacteria (LABs) present in the traditional quesillo of Oaxaca, Mexico. Quesillo samples were collected in three municipalities in Oaxaca, Mexico. Serial dilutions were prepared from 10 g of sample, then seeded in a Man, Rogosa, and Sharpe (MRS) selective medium. Subsequently, they were incubated at 30 °C for 24 to 48 h. The strains were identified macroscopically and microscopically, catalase and oxidase tests were performed as confirmation tests for LAB. From the three traditional quesillo samples, 86 colonies with BAL macroscopic morphology were identified, strains with yeast morphology, coccobacillary, catalase and oxidase positive were discarded, and finally 56 strains were identified with macroscopic and microscopic characteristics of LAB type, gram positive, bacillary and coccobacillary morphology, catalase and oxidase negative. In conclusion, quesillo is a traditional product that presents lactic acid bacteria as important microorganisms, which, in addition to improving sensory attributes and food preservation, can present probiotic properties that when administered in adequate amounts confer a health benefit to the host.

Microbiological and Chemical Characteristics of Yoghurt Incorporated with Watermelon Rind Powder

Watermelon rind accounts for approximately one-third of the overall fruit mass. It is usually discarded due to its low commercial value. However, it is reported to contain valuable nutrients and is an effective source of pectin that can act as a potential prebiotic. This study aimed to study the effects of watermelon rind powder (WRP) on the growth of probiotic bacteria in yoghurt and its chemical characteristics. Watermelon rind was dried by using a dehydrator and ground into powder form before being incorporated into fresh yoghurt at 2% and 4% w/v. A sample with 0% w/v WRP was prepared as control. The effect of WRP on the growth of probiotic bacteria was determined by MRS plate count. Chemical analyses including titratable acidity, pH and Brix were conducted during the fermentation process. The results showed that the increase in WRP percentage resulted in a significant increase in bacterial growth with 7.20 ± 0.22 log CFU/mL for the control sample as compared to 8.42 ± 0.23 log CFU/mL for sample with 4% WRP after 30 hr of incubation. The fermentation time was also improved with the presence of WRP with a 0.22 h-1 increase in growth rate observed for the sample with 4% WRP as compared to the control sample. Furthermore, samples containing 4% WRP showed the highest increment in titratable acidity (12.47) and the highest percentage in Brix value reduction (51.04%) during the fermentation period as compared to the control sample. Biochemical analysis showed negative values for oxidase and catalase test while positive values were obtained for gram-staining indicating the presence of Lactic acid bacteria from the gram-positive group. This study demonstrates the high potential of WRP in promoting bacterial growth for yoghurt production which is beneficial to the food industry other than promoting the ongoing effort of food waste reduction.

Comparing lactic acid bacteria biodiversity in irritable bowel syndrome and healthy gut microbiota.

Irritable bowel syndrome (IBS) is a prevalent gut disorder linked to changes in the gut microbiota, including lactic acid bacteria (LAB). However, research on LAB biodiversity in IBS patients is limited. This study aimed to compare LAB microbiota in healthy individuals and those with IBS through biochemical and molecular techniques. Fecal samples from 15 IBS patients and 13 healthy individuals were collected, and LAB were isolated using biochemical methods. Fifty isolates were chosen based on Gram staining and catalase tests and identified through 16S rRNA gene sequencing. A phylogenetic tree was used to analyze strain diversity, and correlation diagrams and swarm plots were employed to explore variable relationships. The study revealed a significant difference in LAB numbers between IBS and healthy subjects, with average of 5.91 and 6.63, respectively. Most bacteria were Gram-positive cocci or bacilli, with homofermentative characteristics, except for one heterofermentative sample from the healthy group. Both IBS and healthy groups exhibited strains from Lactobacillus and Enterococcus genera, with Enterococcus faecium being predominant in both. Demographic analysis showed higher IBS prevalence among individuals aged 20-40, with IBS-C more common in women and IBS-D in men. The study concluded that individuals with IBS had significantly lower LAB microbiota counts, potentially impacting intestinal defense function. Further exploration of LAB behavioral and immunomodulatory traits may enhance understanding of intestinal microbiota's role in IBS and aid in developing treatment strategies.