Bacterial Isolates Research Articles

Optimization of bacteriophage therapy for difficult-to-treat musculoskeletal infections: a bench-to-bedside perspective

Given the increasing threat of antimicrobial resistance, scientists are urgently seeking adjunct antimicrobial strategies, such as phage therapy (PT). However, despite promising results for the treatment of musculoskeletal infections in our center, crucial knowledge gaps remain. Therefore, a prospective observational study (PHAGEFORCE) and a multidisciplinary approach was set up to achieve and optimize standardized treatment guidelines. At our center, PT is strictly controlled and monitored by a multidisciplinary taskforce. Each phage treatment follows the same pathway to ensure standardization and data quality. Within the PHAGEFORCE framework, we established a testing platform to gain insight in the safety and efficacy of PT, biodistribution, phage kinetics and the molecular interaction between phages and bacteria. The draining fluid is collected to determine the phage titer and bacterial load. In addition, all bacterial isolates are fully characterized by genome sequencing to monitor the emergence of phage resistance. We hereby present a standardized bench-to-bedside protocol to gain more insight in the kinetics and dynamics of PT for musculoskeletal infections.

Carbapenemase and extended spectrum beta-lactamase producing bacteria in waters originating from a single landfill in Slovenia.

Groundwater, rainwater, and leachate associated with a single landfill were analysed to detect extended spectrum beta-lactamase (ESBL) producing and carbapenemase (CP) producing bacteria. After cultivation on three commercial selective-differential media, 240 bacterial isolates were obtained and identified by MALDI-TOF MS. Isolates from clinically relevant species were further genotyped by Enterobacterial Repetitive Intergenic Consensus (ERIC) polymerase chain reaction (PCR), tested for antibiotic susceptibility and presence of carbapenemases and ESBL enzymes. Two ESBL producing isolates and two isolates producing carbapenemases were detected in rainwater, groundwater and in leachate: Klebsiella oxytoca complex with the gene for the ESBL enzyme CTX-M-1 and the gene for the carbapenemase OXA-48, Serratia fonticola with the gene for the ESBL enzyme FONA-2 and Pseudomonas aeruginosa with gene coding VIM metallo-beta lactamase. Our study indicates that bacteria with ESBL and CP genes can be present in landfill-associated waters.

Phytochemical Screening And Antimcrobial Efficacy of Leaf Extract Of Guava (Psidium guajava) On Selected Bacteria

Guava leaf extract has analgesic, anti-inflammatory, antimicrobial, hepato protective and antioxidant activities. The high resistance of bacteria to modern day drugs has led researchers in the pharmaceutical industry to look towards plant-based extracts for solutions. Hence, this studywas aimed at evaluating the phytochemical and antibacterial efficacy of leaf extracts of Psidium guajava (guava) on some selected bacteria. Pure isolates of bacteria gotten from urine of patients in Charis Rhema Research and Diagnostic Laboratory were used in the study. Extracts from the leaves of Psidium guajava were tested for presence of phytochemicals. Separation of active components of the extracts was one using Chromatographic technique. The antibacterial activityof Psidium guajava leaves was determined using agar diffusion bioassay. Phenols were present at all concentrations (100, 80 and 60mg). The study discovered a significant relationship between extract concentration and the zones of inhibition at 60% N-hexane/40% methanol for Klebsiellasp., and 0.0% N-hexane/100% methanol for S. aureus. Flavonoids, tannins, saponins and phenols were the active compounds in guava that helped in the inhibition of growth on the sampled isolates. Methanol and N-hexane extracts of guava can be used as potent medicines for inhibitingthe growth of Klebsiella and Staphylococcus aureus.

Antibacterial Efficacy of Saudi Coriandrum sativum L. Seed Extract: A Potential Natural Preservative for Enhancing Food Safety and Shelf Life

Objective: This study aimed to demonstrate the antimicrobial activity of an aqueous extract of Saudi Coriandrum sativum L. seeds against bacteria that cause food contamination and food poisoning. Methods: The study utilized an aqueous extract of Saudi Coriandrum sativum L. seeds to assess its antibacterial activity against various bacterial strains associated with food contamination and food poisoning. The bacterial strains tested included Streptococcus sp., Enterococcus faecalis, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa, and Listeria monocytogenes. The bacteria were exposed to the extract for a period of 72 hours, after which their growth rates were measured and categorized to determine the extract's effectiveness in inhibiting bacterial proliferation. Results: The bacterial isolates were divided into three groups based on their growth rates after 72 hours of exposure to the aqueous extract. The first group, which demonstrated the highest susceptibility, included Streptococcus sp. and Enterococcus faecalis, with an average growth reduction of 9.2%. The second group, comprising Bacillus cereus, Staphylococcus aureus, and Escherichia coli, exhibited an average growth reduction of 22.5%. The third group, which included Salmonella enteritidis, Pseudomonas aeruginosa, and Listeria monocytogenes, showed the least susceptibility, with an average growth reduction of 45.8%. Conclusions: The aqueous extract of Coriandrum sativum L. seeds has shown effective inhibition of bacterial growth. While additional research is needed to fully assess its potential, the extract could be recommended as a natural preservative in the food industry. It has the potential to extend shelf life, improve food quality, and safeguard consumer health.

Comparison of Zybio Kit and saponin in-house method in rapid identification of bacteria from positive blood cultures by EXS2600 matrix-assisted laser desorption ionization time-of-flightmass spectrometry system.

We evaluated the performance of Zybio EXS2600 matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) (Zybio Inc., Chongqing, China) for the identification of bacteria from positive blood culture (BC) bottles using Blood Culture Positive Sample Pretreatment Kit (Zybio Inc., Chongqing, China) in comparison to an in-house saponin method. Following a positive signal by the BACTEC™ FX system, confirmation of identification was achieved using subcultured growing biomass used for MALDI-TOF MS analysis. A total of 94 positive BC bottles with 97 bacterial isolates were analyzed. The overall identification rates at the genus and species levels for the saponin method were 89.7% (87/97) and 74.2% (72/97), respectively. With the Zybio Kit, 88.7% (86/97) and 80.4% (78/97) of microorganisms were correctly identified to the genus and species levels, respectively. The saponin method identified 65.3% (32/49) of Gram-positive bacteria at the species level, whereas the Zybio Kit achieved a higher species-level identification rate of 79.6% (39/49) (p= 0.1153). The saponin method with additional on-plate formic acid extraction showed a significantly higher overall identification rate in comparison to the saponin method without that step for both genus (87.6% [85/97] vs. 70.1% [68/97], p= 0.0029) and species level (70.1% [68/97] vs. 46.4% [45/97], p= 0.0008). Identification rates of Gram-negative bacteria showed a higher identification rate, however, not statistically significant with additional Zybio Kit protocol step on both genus (85.4% [41/48] vs. 81.3% [39/48], p= 0.5858) and species level (77.1% [37/48] vs. 75% [36/48], p= 0.8120). Zybio Kit could offer an advantage in species-level identification, particularly for Gram-positive bacteria. The inclusion of on-plate formic acid extraction in the saponin method notably enhanced identification at both genus and species levels for Gram-positive bacteria. The extended protocol provided by the Zybio Kit could potentially offer an advantage in the identification of Gram-negative bacteria at both genus and species levels. Enhancements to the Zybio EXS2600 MALDI-TOF instrument software database are necessary.

Biodegradation of sulfamethoxazole by a bacterium isolated from the Hurricane overtop sediments

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are commonly found in Louisiana's waterways, specifically in the waterways of Bayou Lafourche and the Intracoastal Canal. In August of 2021, Hurricane Ida flooded levees in Larose, Louisiana, where the bayou and canal intersect, and deposited sediment contaminated with industrial chemicals, antibiotics, and ARB. Many multidrug resistant bacteria were isolated from the sediments. One of the bacterial isolates, Alcaligenes faecalis, was able to use sulfamethoxazole (SMX) as its sole nitrogen source and was resistant at concentrations of 500 mg/L of SMX. The objective of this study was to find out the ability of this new isolate to degrade SMX. When this bacterium was grown on a basic mineral salt medium with SMX as the sole nitrogen source, 39.81 % SMX was removed in the culture, which was statistically significant compared to other treatment conditions. HPLC analysis showed the production of many metabolites. LC/MS confirmed the identity of two metabolites as 3-amino-5-methylisoxazole (3A-5M) and 3-hydroxy-5-methylisoxazole (3H-5M). A. faecalis hydrolyzed SMX to produce 3A-5M which was oxidatively deaminated further to yield 3H-5M with the release of ammonia. This reaction occurred only when there was no other nitrogen source other than SMX was present in the culture medium, which showed that this unique feature of the bacteria could be used to degrade SMX from the contaminated environment.

Antibiotic properties of seaweed-associated heterotrophic Bacilli against drug-resistant pathogens

The rise in antibiotic resistance has prompted the exploration of new marine habitats for novel bioactive compounds. Seaweed-associated symbionts have emerged as significant sources of novel antibacterial against nosocomial pathogens. Herein, eighty-one bacterial isolates were obtained through culture-dependent isolation of seaweed symbionts from India's southern coast. Bacillus velezensis SK54 represented the largest share (54 %), followed by Bacillus siamensis SK53 (33 %), Bacillus subtilis SK20 (8 %), and Bacillus filamentous SK55 (5 %). B. siamensis SK53 and B. velezensis SK54, which were separated from seaweeds Turbinaria conoides and Dictyota cervicornis, respectively, demonstrated clearance zones over 25 mm on spot-over-lawn assay against multiple clinical pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Staphylococcus aureus (VRSA). Selected isolates were sensitive to commercially available antibiotics, and no pathogenicity was observed. The isolates did not amplify pore-forming non-haemolytic haemolysin BL (hbl) and enterotoxin (nhe) genes, and haemolysis on blood agar confirmed their non-pathogenic nature. The bacterial extracts exhibited significant antibacterial activity against the tested pathogens, including MRSA and VRSA, with a minimum inhibitory concentration (MIC) range of 6.25–12.5 μg/mL. The 700 bp type-I polyketide synthase (pks) genes (OQ657454, OQ706631, OQ737799, and OQ834957) were amplified from the heterotrophic of B. siamensis SK53 and B. velezensis SK54, with a 99 % identity in the BLAST search. The substantial antibacterial potential against drug-resistant bacteria, along with the presence of genes encoding bioactive lead molecules, suggests that these marine symbiotic bacteria, B. siamensis SK53 and B. velezensis SK54, could be effective in combating emerging antibiotic resistance.

Identification, Antibiotic Profiling of Potential Pathogenic Bacteria from Fomites in Neonatal Intensive Care Units in a Tertiary Teaching Hospital of North Karnataka

This study was taken up to determine the prevalence of potential pathogens in most touched fomites in Neonatal Intensive Care Units (NICUs) and to determine their antibiogram. Fifty swabs each were collected from fomites from In-born (for babies born in our center) and out-born (for babies born elsewhere, brought to our center) NICUs, before and after cleaning. Samples were processed using standard Microbiological techniques. Antibiogram was determined by Kirby-Bauer disc diffusion method. From In-born NICU, before cleaning, 42 (84%) samples yielded growth with 48 bacterial isolates of which 31 (64.6%) were pathogens and after cleaning, 40 (80%) samples yielded growth with 41 bacterial isolates, of which 30 (73.1%) were pathogens. Most frequent isolates were non-fermenting gram-negative bacilli (NFGNB) and Klebsiella pneumoniae before and after cleaning, respectively. Prevalence of bacteria from In-born NICU before and after the cleaning was statistically significant (p = 0.025). From Out-born NICU, before cleaning, 42 (84%) samples yielded growth with 45 bacterial isolates, of which 25 (55.55%) were pathogens. Samples collected after cleaning; 42 (84%) samples yielded growth with 43 bacterial isolates of which 19 (44.18%) were pathogens. Most frequent isolates were NFGNB and Klebsiella pneumoniae from In-born NICU and K. pneumoniae and Escherichia coli from Out-born NICU before and after cleaning, respectively. Overall prevalence of pathogens was significant (p = 0.007). Staphylococcal isolates were resistant to Methicillin. NFGNB exhibited highest resistance (55.9%) towards Gentamicin. Significant decrease in the frequency of pathogens after cleaning indicates stringent practice of sterilization protocol would be essential in hospital environment.

Microbial Protein Synthesis by Cellulolytic Bacterial Isolates from Feces of Indonesian Endemic Herbivores

Cellulolytic bacterial play an important role in the synthesis of microbial protein in the small intestine as high-quality protein. This research aimed to observe the growth patterns of cellulolytic bacterial isolates from the feces of endemic herbivorous animals in Indonesia, and to evaluate the effect of the addition of cellulolytic bacterial isolates on the synthesis of microbial proteins in vitro. The study used a completely randomized design with four treatments and five replications. The treatments included T0 = Concentrate mix 40%: elephant grass 30%: palm leaves 30% (control), T1 = T0 + 105 CFU mL-1 cellulolytic bacterial isolate, T2 = T0 + 106 CFU mL-1 cellulolytic bacterial isolate, and T3 = T0 + 107 CFU mL-1 cellulolytic bacterial isolate. Variables measured were the growth pattern of bacterial isolates, bacterial population at the optimal growth point, and microbial protein synthesis. The results showed growth pattern of cellulolytic bacterial isolates from Muntjac, Deer and Anoa feces have similar pattern, and was different from the growth pattern of bacterial isolates from bison feces. The optimal growth point of cellulolytic bacterial isolates from the feces of Muntjac, Deer, and Anoa at the 8th hour of incubation with bacterial populations of 1.3 x 109 CFU mL-1, 1.7 x 109 CFU mL-1, and 1.4 x 109 CFU mL-1. The growth pattern and optimal point of cellulolytic bacterial isolates from the feces of Bison at the 12th hour after incubation with bacterial populations of 1,1 x 1010 CFU mL-1. The addition of cellulolytic bacterial isolates did not affect microbial protein synthesis.

Anti-quorum Sensing Activity and Bioactive Components of Marine-derived Bacteria

Understanding and harnessing quorum sensing activity and identifying bioactive substances produced by marine-derived bacteria are essential for exploring their potential applications in various fields, including biotechnology, pharmaceuticals, and environmental management. This research aims to investigate the quorum-sensing activities employed by these bacteria and to characterize the bioactive compounds they produce, to unlock their therapeutic, industrial, and ecological potentials. This study focuses on screening, isolation and characterization of marine bacteria from Thoothukudi Harbour Beach, India, and potential antibacterial and anti-quorum sensing activities of their respective spent media against biofilm forming pathogens. Three soil samples were collected and processed for bacterial isolation. Seventeen different bacterial isolates were obtained and identified after prior culture. Antibacterial activity was evaluated against four pathogenic bacteria, with some isolates demonstrating significant inhibition. Additionally, biofilm inhibition assays were conducted, revealing the ability of certain isolates to inhibit the formation of biofilms. The secondary metabolites present in the ethyl acetate fraction of I.B 6 isolate exhibiting relatively high antibacterial and antibiofilm properties were identified by GC-MS. Anti-quorum sensing activity was also investigated using swarming assay and the MIC was determined accordingly for the ethyl acetate fraction. Hence, these marine bacteria hold for producing bioactive compounds with potential pharmaceutical and industrial applications. Finally, the positive organism is subjected to 16S rRNA sequencing for identification and was found to be Bacillus thuringiensis.

Molecular detection and antibiogram profiles of Escherichia coli and Vibrio cholerae isolated from raw vegetables in the northern district of Bangladesh

Raw vegetables are essential for a well-balanced diet as they provide vitamins, minerals, dietary fiber, and phytochemicals. This study aimed to isolate, identify, and evaluate the microbial loads of Escherichia coli and Vibrio cholerae in raw vegetables sold at local markets in the Dinajpur district of Bangladesh. A total of 35 vegetable samples were collected from four markets in Dinajpur district. The isolates were identified using cultural, staining, biochemical, and molecular tests. Microbial loads were enumerated (TVC) using the pour plate technique. Molecular detection of bacterial species was confirmed targeting the 16S rRNA and groEL genes of E. coli and V. cholerae, respectively. The amplification was done on 704 bp fragments of the 16S rRNA gene of E. coli and 1117 bp fragments of Vibrio spp. For the confirmation of V. cholerae, amplification of a 418 bp fragment of the groEL gene was performed through multiplex PCR. An antimicrobial susceptibility test was conducted on all isolates of bacteria against eleven and eight antibiotics by disc diffusion. The total viable count (TVC) in potato, carrot, cabbage, cauliflower, tomato, green chili, cucumber, mustard sak, and coriander leaves were 2.4 ± 0.37, 2.2±0.14, 2.1±0.26, 1.8±0.14, 1.7±0.27, 1.5±0.33, 1.5±0.33, and 1.4±0.25 mean log colony forming units ± standard deviation/mg, respectively. Out of 35 raw vegetable samples, 16 (45.71%) and 13 (37.14%) isolates were culture positive for E. coli and V. cholerae. Subsequently, 5 (31.25%) and 4 (30.76%) isolates of E. coli and V. choleraewere confirmed positive molecularly. All 16 and 13 isolates of E. coli and V. cholerae were subjected to antibiogram testing against 11 and 8 antibiotics. E. coli isolates were highly resistant to ceftazidime, cefixime, ampicillin, and oxytetracycline, but sensitive to gentamycin, ceftriaxone, colistin, and enrofloxacin. Similarly, V. cholerae isolates were highly resistant to nalidixic acid, trimethoprim, and polymyxin, but highly sensitive to kanamycin, gentamicin, and streptomycin. The study’s findings indicate that raw vegetables pose a significant public health risk due to MDR E. coli and V. cholerae. To achieve safer levels of these bacteria in raw vegetables, good production practices and hygiene awareness are essential.

Green synthesized silver nanoparticles from Ocimum sanctum: A potent inhibitor of biofilm forming ability and efflux pumps in bacteria causing bovine mastitis

Therapeutic management of mastitis faces significant challenges due to multidrug resistance. In the present study, multi-drug-resistant (MDR) Staphylococcus spp, Klebsiella pneumoniae, and Escherichia coli were isolated from bovine clinical mastitis cases and the phenotypic and genotypic multidrug resistance profiling was carried out. Silver nanoparticles (AgNPs) were biosynthesized using Ocimum sanctum leaf extracts and characterized via UV Vis absorption, Fourier Transform Infrared Spectroscopy, X-ray diffraction studies, Energy dispersive spectroscopy and Electron Microscopy. The determined minimum inhibitory concentration and minimum bactericidal concentration of the AgNPs against the recovered MDR isolates were 62.5μg/ml and 125μg/ml respectively. At a concentration of 50μg/ml, the AgNPs demonstrated biofilm inhibitory activities of 80.35 % for MDR E. coli, 71.29 % for S. aureus and 60.18 % for MDR K. pneumoniae. Post-treatment observations revealed notable differences in biofilm formation across bacterial isolates. Furthermore, AgNP treatment led to significant downregulation of expression of the efflux pump genes acrB, acrE, acrF, and emrB in Gram-negative isolates and norB in Staphylococci isolates. This research underscores the potential for the development of an eco-friendly antimicrobial alternative in the form of green synthesized silver nanoparticles to combat drug resistance offering potential antibiofilm and efflux pump inhibitory activities.

Improving the odds: Artificial intelligence and the great plate count anomaly.

Next-generation DNA sequencing has shown that the great plate count anomaly, that is, the difference between bacteria present in the environment and those that can be obtained in culture from that environment, is even greater and more persisting than initially thought. This hampers fundamental understanding of bacterial physiology and biotechnological application of the unculture majority. With big sequence data as foundation, artificial intelligence (AI) may be a game changer in bacterial isolation efforts and provide directions for the cultivation media and conditions that are most promising and as such be used to canalize limited human and financial resources. This opinion paper discusses how AI is or can be used to improve the success of bacterial isolation.

Biofilm-forming bacteria associated with corals secrete melanin with UV-absorption properties.

Corals are colonized by a plethora of microorganisms, and their diversity plays a significant role in the health and resilience of corals when they face oxidative stress leading to bleaching. In the current study, we examined 238 bacteria isolated from five different coral species (Acropora hyacinthus, Pocillopora damicornis, Podabacea crustacea, Porites lobata, and Pavona venosa) collected from the coral reef ecosystems of Kavaratti, Lakshadweep Islands, India. We found that bacteria such as Psychrobacter sp., Halomonas sp., Kushneria sp., Staphylococcus sp., Bacillus sp., Brachybacterium sp., Citrobacter sp., and Salinicola sp. were commonly present in the corals. On the other hand, Qipengyuania sp., Faucicola sp., Marihabitans sp., Azomonas sp., Atlantibacter sp., Cedecea sp., Krasalinikoviella sp., and Aidingimonas sp. were not previously reported from the corals. Among the bacterial isolates, a significant number showed high levels of biofilm formation (118), UV absorption (119), and melanin production (127). Considering these properties, we have identified a combination of seven bacteria from the genera Halomonas sp., Psychrobacter sp., Krasalinikoviella sp., and Micrococcus sp. as a potential probiotic consortium for protecting corals from oxidative stress. Overall, this study provides valuable insights into the coral microbiome and opens up possibilities for microbiome-based interventions to protect these crucial ecosystems in the face of global environmental challenges.

Bacillus Species Consortium as a New Starter in the Optimization of Cassava Tuber Retting

This work aims to contribute to the elaboration of a stater consortium of performing <i>Bacillus</i> Spp capable of significantly standardizing the retting of cassava tubers. We monitored the retting, and the changes in multiple parameters, including pH, titrable acidity, bacterial level, texture profiles, volatile flavor compounds, and sensory quality. We proceeded with the isolation of bacteria of the genus <i>Bacillus</i> which were further characterized by classical microbiology techniques. In total, fifty-seven bacteria were obtained. Some of them were confirmed by FibE multiplex PCR. The identified organisms belonged to three <i>Bacillus</i> species: <i>B. subtilis</i>, <i>B. pumilus</i>, and <i>B. safensis</i>. Based on the Penetrometry Indices after 24, 48 and 72 hours (PI48) and enzymatic profiles, 24.5% (14) from Mokiki presented interesting fermentation potential, these were selected to realize seventy-seven <i>Bacillus</i> spp consortia in duo. 12% could easily soften cassava tubers after 24 and 48 hours (PI24≥6 and PI48≥8). These consortia allowed the retting of cassava with a shorter fermentation time of two days. <i>Bacillus</i> constituting the consortia also showed the ability to produce a range of biomolecules potentially involved in their fermentative capacity including Pectinase, Amylase, Protease and Biosurfactant.

Assessment of Antifungal Potential of Rhizospheric Bacterial Isolates of Daucus carota against Rhizoctonia solani

Rhizoctonia solani is an important plant pathogen which is responsible for causing a number of plant diseases in a variety of cropping plants. The current studies were carried out to explore antifungal potential of bacteria isolated from rhizospheric region of Daucus carota against Rhizoctonia. Of the total 21 bacterial isolates isolated, only 3 isolates namely CVO-3, CVO-4 and CRY-O-2 were shown antifungal potential against Rhizoctonia. Besides having antifungal potential these isolates also have some plant growth promoting attributes that will be an extra benefit of using these isolates as a biofungicides against R. solani. Thus, these isolates could be used as biofungicides against Rhizoctonia to prevent a variety of plant diseases like sheath blight in Oryza sativa, stem canker and black scurf in Solanum tuberosum and seedling diseases in Brassica napus. The isolates CVO-3, CVO-4 and CRY-O-2 were also characterized biochemical level by using methods based on Determinative Bacteriology given in Bergey’s manual and at molecular level using 16S rRNA sequencing and sequences of 16S rDNA segment were submitted to NCBI in GenBank database with the accession numbers OR775574 (Lysinibacillus boronitolerans ss3cvo3), OR775575 (Lysinibacillus boronitolerans ss4cvo4) and OR708523 (Shouchella rhizosphaerae ss1cryo2). The present investigation is an approach towards the use of these bacterial isolates from carrot rhizosphere to control the activities in the rhizosphere of other cropping plants.

Isolation and characterization of Bacillus bacteria with antagonistic properties against the pathogens Alternaria alternata and Fusarium graminearum.

Isolation and characterization of Bacillus bacteria with antagonistic properties against the pathogens Alternaria alternata and Fusarium graminearum.

Isolation, Characterization and Optimization of Indigenous Petrol Degrading Bacteria from Oil Contaminated Soil

Petroleum-derived products like petrol, containing complex hydrocarbons, have catastrophic environmental effects, posing a universal challenge. Bioremediation is known as eco-friendly and safe technique for removal of hydrocarbon pollutants. In this study, indigenous bacteria were isolated from oil contaminated soils and screened for their biodegradation potential. The bacterial enrichment and isolation were done using selective media Bushnell-Haas supplemented with petrol as a sole carbon source. Out of fifteen isolated strains best two isolates S4P2 and S14P1 were selected on basis of DCPIP screening method. These isolates were identified as Pseudomonas chengduensis & Pseudomonas donghuensis by 16S rRNA gene sequencing. The growth parameters were optimized by one factor at a time. The optimum growth temperature for P.chengduensis & P. donghuensis was found to be 37°C at pH 7 with a substrate concentration of 1%.

Antibiotic Susceptibility of Bacteria Isolated from Livestock-exposed and Unexposed Areas in Perlite-rich Soil in Thailand

Antibiotic resistant bacteria are present in various environments and are concerning for public health. Antibiotic resistance genes in soil may proliferate throughout different ecosystems and be acquired by pathogens that pose health risks to humans and animals. This study investigated the antibiotic resistance of cultivable bacteria isolated from livestock-exposed and unexposed areas in a former perlite mining area in the Fa-La-Mee Mountain range, Lopburi, Thailand. Soil samples were collected in five different locations. Soil bacteria were isolated and tested for susceptibility against seven antibiotics, followed by 16S rRNA gene-based identification. A total of 56 bacterial isolates were isolated from the perlite-rich soil samples, including 34 isolates from the livestock-exposed areas and 22 isolates from the unexposed areas. Most of the isolates were resistant to cefepime (26.5% in exposed areas and 22.7% in unexposed areas) and ampicillin (23.5% in exposed areas and 22.7% in unexposed areas). 16S rRNA gene sequences revealed that most of the resistant bacteria isolated from perlite-rich soil were Bacillus spp. A multidrug-resistant isolate of Bacillus cereus resistant to ampicillin, trimethoprim/sulfamethoxazole, and cefepime was found in a livestock-unexposed area. The majority of the culturable antibiotic-resistant bacteria isolated from perlite-rich soil were cefepime-resistant Bacillus. Interestingly, the pattern of antibiotic resistance in exposed and unexposed areas was not different, which indicated that antibiotic resistance in perlite-rich soil is likely caused by other factors, such as physicochemical characteristics and/or the microbial population of the soil rather than by antibiotics used in livestock husbandry.

Antimicrobial Activity of Senna didymobotrya and Thunbergia alata Plant Extracts Against Selected Bacterial Clinical Isolates from Kericho Referral Hospital in Kenya

Bacterial infections are distributed worldwide and cause deadly infectious bacterial diseases such as skin, soft tissue and respiratory tract infections, meningitis, and tuberculosis. Bacterial infections are very common and can be easily acquired since bacteria are ubiquitous. It has challenged modern healthcare providers; conventional drugs are costly and have side effects. Therefore, alternative remedies that are easily available, affordable, and effective are needed. This study was carried out to determine the antimicrobial activity of Senna didymobotrya and Thunbergia alata crude plant extracts against Staphylococcus aureus, Streptococcus pyogenes and pseudomonas aeruginosa common in Kericho County. Plant leaves of the two plants were sourced from two sites (Bomet and Kabianga), dried, milled into powder and solvent extracted using hexane, dichloromethane: methanol ratio (1:1) and methanol. Phytochemicals present in each plant extract were evaluated using standard laboratory procedures. Antimicrobial sensitivity testing, Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentration (MBC) were determined. Discs impregnated with standard antibacterial drugs were used as positive control. Leaves of T. alata and Senna didymobotrya collected from Bomet contained 7.41% and 10.4% while those from Kabianga contained 8.07% and 17.71% of extracts respectively, suggesting that site conditions do not influence the percentage of extracts. Leave extracts of S. didymobotrya and T. alata were found to be rich in alkaloids, flavonoids, terpenoids, glycosides and tannins irrespective of plant collection site, solvent of extraction. S. didymobotrya and T. alata plant extracts significantly inhibited growth of the exposed microbes in the following order: S. aureus, ≥S. pyogenes and≥ P. aeruginosa bacteria in comparison with commercial antibiotics (penicillin, chloromphenical, and erythromycin). The MIC values of the isolates ranged from 20×10-3 mg/ml to 4.8 ×10-3 mg/ml. However, bacterial inhibition by plant extracts showed re-growth of S. pyogenes after 36 hours, suggesting bacteriostatic nature. These results suggest that S. didymobotrya and T. alata leaves contain significant amounts of alkaloids, flavonoids, terpenoids, glycosides and tannins hence can be used as traditional medicine to manage S. aureus, S. pyogenes and P. aeruginosa bacteria found on human skin