Bacilli Isolated Research Articles

Optimization of subtilisin production from Bacillus subtilis strain ZK3 and biological and molecular characterization of synthesized subtilisin capped nanoparticles

The increase and dissemination of multi-drug resistant bacteria have presented a major healthcare challenge, making bacterial infections a significant concern. The present research contributes towards the production of bioactive subtilisin from a marine soil isolate Bacillus subtilis strain ZK3. Custard apple seed powder (raw carbon) and mustard oil cake (raw nitrogen) sources showed a pronounced effect on subtilisin production. A 7.67-fold enhancement in the production was evidenced after optimization with central composite design-response surface methodology. Subtilisin capped silver (AgNP) and zinc oxide (ZnONP) nanoparticles were synthesized and characterized by UV–Visible spectroscopy. Subtilisin and its respective nanoparticles revealed significant biological properties such as, antibacterial activity against all tested pathogenic strains with potential against Escherichia coli and Pseudomonas aeruginosa. Prospective antioxidant behavior of subtilisin, AgNP and ZnONP was evidenced through radical scavenging assays with ABTS and DPPH. Subtilisin, AgNP and ZnONP revealed cytotoxic effect against cancerous breast cell lines MCF-7 with IC50of 83.48, 3.62 and 7.57 µg/mL respectively. Characterizations of nanoparticles were carried out by Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray, X-ray diffraction, thermogravimetric analysis and atomic force microscopy analysis to elucidate the structure, surface and thermostability properties. The study proposes the potential therapeutic applications of subtilisin and its nanoparticles, a way forward for further exploration in the field of healthcare.

Antibiotic resistance of bacteria responsible for postoperative wound infections seen in the laboratory of the University Hospital of Befelatanana.

The management of postoperative wound infections is a major problem in hospitals due to the frequent ineffectiveness of antibiotic treatment. The objectives of this study are to identify the bacteria responsible for postoperative wound infections and to describe these antibiotic resistances in order to improve the management of these infections. It is a prospective study of 52 bacteriological results of postoperative wounds for a period of six months from January 2021 to June 2021 in the laboratory of the University Hospital of Befelatanana. This study showed 26 (50%) isolates of staphylococci, 17 (32.7%) isolates of enterobacteria, 6 (11.5%) isolates of streptococci and 3 (5.8%) isolates of nonfermenting gram-negatif bacilli. Antibiotic resistance, varies from 0% (vancomycin) to 92.3% (penicillin G) for staphylococci isolates, 0% (imipenem, amikacin) to 94.1% (amoxicillin) for enterobacteria isolates, 0% (vancomycin) to 50% (penicillin G) for streptococci isolates and 33% (imipenem, amikacin) to 100% (cotrimoxazole) for the isolates of nonfermenting gram-negatif bacilli. The knowledge of antibiotic resistance of bacteria responsible for postoperative wound infections allows better patient management.

Optimum conditions for the biodegradation of waste low-density polyethylene strips by bacteria isolated from parts of north central Nigeria

Optimum conditions (Temperature, pH and incubation time) were studied for selected bacterial isolates Pseudomonas aeruginosa1(PA1), Pseudomonas aeruginosa2 (PA2), Bacillus megaterium, Providencia stuarti, Alcaligenes faecalis, Enterobacter hormaechei, Klebsiella pneumonia and Proteus vulgaris to biodegrade low-density polyethylene (LDPE) waste by using Basal Salts Medium (BSM) containing 0.500g LDPE strips (1 cm by 5 cm each) using changes in mechanical properties and weight loss of the strips as indicators for ability of these microorganisms to degrade LDPE. The results revealed that four of the eight bacterial isolates, Pseudomonas aeruginosa1, Pseudomonas aeruginosa2, Bacillus megaterium, and Providencia stuarti showed high ability to degrade the LDPE strips after 8 weeks of incubation in liquid Basal Salts Medium at pH 6.5 -7.5 and 32oC. The tensile strength of the LDPE strips was reduced by 0.047±0.41 MN/M2 (47%) for P. aeruginosa1, 0.040±0.30 MN/M2 (40%) for P. aeruginosa2, Bacillus megaterium, 0.033±0.61 MN/M2 (33%), and Providencia stuarti, 0.027±0.41 MN/M2 (27%). The weight loss of the LDPE recorded for Pseudomonas aeruginosa1 was 19.80±0.04 %, for Pseudomonas aeruginosa2 19.40±0.08 %, 13.40±0.10 %, for Bacillus megaterium and 19.20±0.42 % for Providencia stuarti respectively. There was significant difference in the weight loss of the LDPE strips at pH 6.5 for Bacillus megaterium, Providencia stuarti, Alcaligenes faecalis and Enterobacter hormaechei and at 30-32 oC for Pseudomonas spp., Bacillus megaterium, Klebsiella pneumonia and Proteus vulgaris(P>0.05 %).

Isolation and Screening of Bioactivities from Bacillus sp. Isolated from Banana Rhizosphere

Bacillus sp. has been widely known to produce various bioactive metabolites related to plant growth. Bacillus sp. has also been known as one of the plant growth-promoting bacteria. In this study, a total of 68 isolates of Bacillus sp. were isolated from the rhizosphere of banana plantation using soil suspension technique. Isolated Bacillus sp. was then subjected to screening of their secondary metabolites such as cellulase, mannanase, xylanase, indole-acetic-acid, and gibberellic acid production before potential isolates were chosen and identified using their 16S rRNA and later subjected to seed germination testing. It was observed that Bacillus sp. isolated produces most of cellulase but did not have much affinity to produce gibberellic acid as only 5 Bacillus sp. were observed producing gibberellic acid. Three of the potential Bacillus sp. were selected and identified as Bacillus pumilus strain PNO21, Bacillus amyloliquefaciens strain PNO7 and Bacillus wiedmannii strain PNO28. Seed germination test also revealed that these 3 Bacillus sp. did not inhibit the seeds germination.

Endophytic establishment of native Bacillus thuringiensis strain in maize plants and its efficacy against Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

BackgroundBacillus thuringiensis (Bt) is known as the most successful microbial insecticide worldwide used against lepidopteran insect pests in agriculture. Native Bacillus isolate VKK5 showing insecticidal activity against Spodoptera frugiperda (FAW) (J.E. Smith) (Lepidoptera: Noctuidae) was characterized as B. thuringiensis (BtVKK5) on a morphological and molecular basis. Recent research has shown that Bt can be established as an endophytic organism for controlling insect pests. The present work aimed at assessing the colonization of BtVKK5 as an endophyte in five maize cultivars by seed treatment (ST), soil drenching (SD), foliar application (FA) and combination of all methods (ST + SD + FA) and its bioefficacy against neonates of FAW.ResultsEstablishment of inoculated BtVKK5 as endophytes in five maize cultivars, viz. Pusa HQPM7 Improved, Pusa Jawahar Hybrid Maize 1, Pusa Vivek Hybrid 27 Improved (PVH27I), Pusa HQPM5 Improved and DMRH 1301, was confirmed by re-isolating from the leaves of the plant on ampicillin-selected agar plates. Estimation of colony-forming units per gram of leaf showed that there was a significant difference in colonization of the Bt strain among maize cultivars by different inoculation methods. The colonies were further substantiated by the amplification of cry1A and cry1E genes. Bioefficacy studies showed the highest mortality (50%) in the ST + FA + SD inoculation method, followed by ST (40%) in PVH27I. Moreover, growth inhibition was observed in survived larvae on inoculated plants vis-a-vis control.ConclusionEstablishment of Bt strain as an endophyte in maize plants, complemented with insecticidal activity, could possibly lead to an innovative approach to the management of S. frugiperda and other borers.

In-vitro Assessment of Native Plant Growth Promoting Rhizobacterial Isolates Against Diverse Fungal Phytopathogens

Although many Plant growth promoting rhizobacteria (PGPR) are used commercially, there is a need to explore more biocontrol agents to combat various pathogens and sustain the productivity of crops. PGPRs inhabit the rhizosphere region of plant and are effective in managing various pathogens. In this study, twenty-six PGPR isolates were screened in-vitro against various fungal phytopathogens in the Plant Bacteriological Laboratory, Department of Plant Pathology, Bidhan Chandra Krishi Vishwavidyalaya, Mohanpur, Nadia, West Bengal during 2021-22. All the thirteen native Bacillus isolates, showed antagonistic activity against Alternaria alternata, Colletotrichum gloeosporioides, Pestalotiopsis sp., Rhizoctonia solani and Sclerotium rolfsii. Among the thirteen fluorescent pseudomonads, all showed antagonistic activity against A. alternata, C. gloeosporioides and Pestalotiopsis sp., eight, CK2LPP, CK2LP8, CK2LP12, GP2, GP8, G11SP37, K11SP4 and S21SP14, against R. solani, two, GP2 and GP8, against S. rolfsii. BRB 42, BRB 56, PR 18, GP2 and GP8 had the highest antagonistic activity against the fungal pathogens under in-vitro condition based on average mycelium inhibition per cent. BRB 56, SM 9 and GP8, showed the maximum inhibition zone against all the phytopathogens.

Multi-enzymatic degradation potential against wastes by the novel isolate of Bacillus

Multi-enzymatic degradation potential against wastes by the novel isolate of Bacillus

Isolation and identification of Bacillus species from soil and assessment of antimicrobial properties

The emergence of multi drug resistant pathogens such as Methicillin resistant Staphylococcus aureus (MRSA) has become a threat to public health. Thus, the development of new antibiotics has become a global concern. Many scientists are attracted towards discovery of new antimicrobial agents from microbial sources. The aim of this study is to isolate potential Bacillus species from soil for the production of antimicrobial substance. During the study, 20 soil samples were collected from various areas of Kathmandu valley. A total of 70 Bacillus isolates were identified by morphological and biochemical characteristics. Altogether 39 isolates were able to produce antibacterial extract when it was grown in Trypticase soya broth (TSB) at 37°C for 48 h. The antimicrobial activity was tested against test organisms like Escherichia coli, Klebsiella pneumoniae, Salmonella, Pseudomonas, Staphylococcus aureus and Candida by Agar well diffusion method. All of the extracts showed zone of inhibition against E. coli except 6 extracts (E39, E43, E36, E25, E45 and E46). The highest zone of inhibition was shown by extract B68 with 11 mm. Only one extract (E62) was able to inhibit the growth of Pseudomonas. The extract from Bacillus isolate (E35) showed highest zone of inhibition against S. aureus (6mm). The protein nature of the extracts was determined by Biuret and Ninhydrin tests. The extracts were relatively stable to heat treatment and unstable to surfactants like 70% methanol, 2-propanol and ethylacetate. The study revealed that soil is a good source for the potential antimicrobial producer bacteria.

Antimicrobial Susceptibility of E. coli Isolates from Intra-Abdominal Infections in the Asia-Pacific Region: Trends in Ciprofloxacin, Ceftriaxone, Cefepime, and Piperacillin/Tazobactam Susceptibility.

To investigate the antibiotic susceptibility of Escherichia coli isolates in patients diagnosed with intra-abdominal infections (IAIs) in the Asia-Pacific region. This study was conducted at 50 medical hospitals across 9 countries/regions as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance program from 2014 to 2018. Nonduplicate isolates of aerobic and facultative gram-negative bacilli were collected and processed for further antimicrobial susceptibility testing. A total of 10,709 isolates were collected, with E. coli (n=4737, 44.2%) being the leading pathogen causing IAIs, followed by Klebsiella pneumoniae (n=2429, 22.7%) and Pseudomonas aeruginosa (n=931, 8.7%). Community-associated (CA) E. coli isolates generally exhibited higher susceptibility rates for most antibiotics than hospital-associated (HA) isolates. In countries/regions other than Hong Kong, South Korea, and Singapore, HA isolates displayed lower susceptibility rates for multiple classes (≥4) of antibiotics. Among the commonly used antibiotics in IAIs, the overall susceptibility rate for ciprofloxacin was low, with an average of 41.3%. Ceftriaxone susceptibility rates in all selected countries were below 80% starting in 2018, ranging from 23.3% to 75.8%. The cefepime susceptibility rates varied across regions, with consistently reduced susceptibility ranging from 45.5% to 57.8% in India, Thailand, and Vietnam. Piperacillin/tazobactam demonstrated effectiveness against E. coli isolates in almost all countries except India, with a downward trend observed in the Philippines and Taiwan. Carbapenems remained effective against more than 90% of E. coli isolates, except in India. Prudent use of fluoroquinolones and ceftriaxone is advised when treating both CA and HA IAIs in the Asia-Pacific region. The low susceptibility rate of cefepime in India, Thailand, and Vietnam needs careful consideration in its administration. Moreover, the increase in nonsusceptibility to piperacillin/tazobactam in the Philippines and Taiwan poses a potential risk that should be closely monitored.

Frenemies of the soil: Bacillus and Pseudomonas interspecies interactions

Bacillus and Pseudomonas ubiquitously occur in natural environments and are two of the most intensively studied bacterial genera in the soil. They are often coisolated from environmental samples, and as a result, several studies have experimentally cocultured bacilli and pseudomonads to obtain emergent properties. Even so, the general interaction between members of these genera is virtually unknown. In the past decade, data on interspecies interactions between natural isolates of Bacillus and Pseudomonas has become more detailed, and now, molecular studies permit mapping of the mechanisms behind their pairwise ecology. This review addresses the current knowledge about microbe-microbe interactions between strains of Bacillus and Pseudomonas and discusses how we can attempt to generalize the interaction on a taxonomic and molecular level.

INDIGENOUS BACILLUS SPECIES ISOLATED FROM AEDES AEGYPTI LARVAE: ISOLATION, LARVICIDAL TOXICITY SCREENING, PHENOTYPIC CHARACTERIZATION, AND MOLECULAR IDENTIFICATION

Vector-borne diseases transmitted by mosquitoes are considered a significant public health problem worldwide. Aedes aegypti is one of the mosquito species responsible for transmitting these diseases. One environmentally friendly method of vector control is the use of microbial agents such as Bacillus species. This study aimed to explore investigate indigenous entomopathogenic bacteria of Bacillus species isolated from A. aegypti larvae. Larvae samples were collected from breeding sites of A. aegypti. All isolates underwent screening and affirmation confirmation tests to assess their larvicidal toxicity against A. aegypti larvae. Phenotypic characterizations and molecular identifications were conducted to determine the species of the Bacillus isolates based on similarity index and percent identity (%ID). Phylogenetic trees were used to compare the isolates with other Bacillus species. The results revealed 120 isolates of Bacillus species from A. aegypti larvae samples. Among them, three isolates (LS3.3, LS9.1, and LSD4.2) exhibited the highest larvicidal toxicity in the confirmation test, resulting in larval mortality rates of 100%, 96.7%, and 100%, respectively, after 48 hours of exposure. Molecular identifications, showed that LSD4.2 had a 99.16% ID with Bacillus velezensis, LS3.3 had a 98.22% ID with Bacillus mojavensis, and LS9.1 had a 99.93% ID with Bacillus subtilis. These three bacteria from the Bacillus genus have been reported to offer significant benefits to humans.

A promising microbial α-amylase production, and purification from Bacillus cereus and its assessment as antibiofilm agent against Pseudomonas aeruginosa pathogen

Background and aimThe purpose of the current study is to isolate a heavily amylase-producing bacteria of the genus Bacillus from soil samples, optimize the production of the enzyme, purify it, and evaluate its activity against biofilm-producing bacteria. A total of 12 soil samples were collected and screened for promising Bacillus species with good amylolytic activity. Isolation was done by serial dilution and plating technique and amylolytic activity was determined by starch agar plate method. Among the 12 Bacillus isolates recovered from soil samples, 7 showed positive α-amylase production. The best isolate that recorded the greatest amylolytic activity was selected for further studies. This isolate was identified by 16S rRNA sequencing as Bacillus cereus and registered under gene bank accession number OP811897. Furthermore, the α-amylase enzyme was produced by a submerged fermentation technique using best production media and partially purified by ammonium sulfate and chilled ethanol and molecular weight had been determined by SDS-PAGE gel electrophoresis. The production of α-amylase was optimized experimentally by one-factor at a time protocol and statistically by Plackett–Burman design as well as RSM CCD design. Data obtained from OFAT and CCD revealed that α-amylase activities were 1.5- and twofold respectively higher as compared to un-optimized conditions. The most significant factors had been identified and optimized by CCD design.ResultsAmong the eleven independent variables tested by PBD, glucose, peptone, (NH4)2SO4, and Mg SO4 were the most significant parameters for α-amylase production with an actual yield of 250U/ml. The best physical parameters affecting the enzyme production were incubation time at 35 °C, and pH 5.5 for 48 h. The partially purified enzyme with 60% ammonium sulphate saturation with 1.38- fold purification showed good stability characteristics at a storage temperature of 4 °C and pH up to 8.5 for 21 days. Antibiofilm activity of purified α-amylase was determined against Pseudomonas aeruginosa (ATCC 35659) by spectrophotometric analysis and CLSM microscopic analysis. Results demonstrated biofilm inhibition by 84% of the formed Pseudomonas biofilm using a microtiter plate assay and thickness inhibition activity by 83% with live/Dead cells percentage of 17%/83% using CLSM protocol.ConclusionsA highly stable purified α-amylase from B. cereus showed promising antibiofilm activity against one of the clinically important biofilm-forming MDR organisms that could be used as a cost-effective tool in pharmaceutical industries.

Activity of ceftolozane/tazobactam and imipenem/relebactam against clinical isolates of Enterobacterales and Pseudomonas aeruginosa collected in central and northern Europe (Belgium, Norway, Sweden, Switzerland)-SMART 2017-21.

To evaluate the in vitro activities of ceftolozane/tazobactam and imipenem/relebactam against clinical isolates of Gram-negative bacilli collected in four central and northern European countries (Belgium, Norway, Sweden, Switzerland) during 2017-21. Participating clinical laboratories each collected up to 250 consecutive Gram-negative isolates per year from patients with bloodstream, intraabdominal, lower respiratory tract or urinary tract infections. MICs were determined by CLSI broth microdilution and interpreted using 2022 EUCAST breakpoints. β-Lactamase genes were identified in select β-lactam-non-susceptible isolate subsets. Ninety-five percent of all Enterobacterales (n = 4158), 95% of ESBL-positive non-carbapenem-resistant Enterobacterales (non-CRE) phenotype Escherichia coli and 85% of ESBL-positive non-CRE phenotype Klebsiella pneumoniae were ceftolozane/tazobactam susceptible. By country, 88% (Belgium), 91% (Sweden, Switzerland) and 96% (Norway) of ESBL-positive non-CRE phenotype Enterobacterales were ceftolozane/tazobactam susceptible. Greater than ninety-nine percent of non-Morganellaceae Enterobacterales and all ESBL-positive non-CRE phenotype Enterobacterales were imipenem/relebactam susceptible. Ceftolozane/tazobactam (96%) and imipenem/relebactam (95%) inhibited most Pseudomonas aeruginosa (n = 823). Both agents retained activity against ≥75% of cefepime-resistant, ceftazidime-resistant and piperacillin/tazobactam-resistant isolates; 56% and 43% of meropenem-resistant isolates were ceftolozane/tazobactam susceptible and imipenem/relebactam susceptible, respectively. By country, 94% (Belgium), 95% (Sweden) and 100% (Norway, Switzerland) of P. aeruginosa were ceftolozane/tazobactam susceptible and 93% (Sweden) to 98% (Norway, Switzerland) were imipenem/relebactam susceptible. Carbapenemase gene carriage among Enterobacterales and P. aeruginosa isolates was generally low (<1%) or completely absent with one exception: an estimated 2.7% of P. aeruginosa isolates from Belgium carried an MBL. Recent clinical isolates of Enterobacterales and P. aeruginosa collected in four central and northern European countries were highly susceptible (≥95%) to ceftolozane/tazobactam and imipenem/relebactam.

Genomic sequencing of fourteen Bacillus thuringiensis isolates: insights into geographic variation and phylogenetic implications

ObjectiveThis work was performed in support of a separate study investigating the activity of pesticidal proteins produced by Bacillus thuringiensis against the Asian citrus psyllid, Diaphorina citri. The fourteen Bacillus isolates chosen were selected from a large, geographically diverse collection that was characterized only by biochemical phenotype and morphology of the parasporal crystal, hence, for each isolate it was desired to determine the specific pesticidal proteins produced, assign each to a Bacillus cereus multilocus sequence type (ST), and predict their placement within the classical Bt serotyping system. In addition, phylogenetic distances between the isolates and Bacillus thuringiensis serovar type strains were determined by calculating digital DNA-DNA hybridization (dDDH) values among the isolates.ResultsBased on the assembled sequence data, the isolates were found to be likely representatives of the Bt serovars kurstaki (ST 8), pakistani (ST 550), toumanoffi (ST 240), israelensis (ST 16), thuringiensis (ST 10), entomocidus (ST 239), and finitimus (ST 171). In cases where multiple isolates occurred within a predicted serovar, pesticidal protein profiles were found to be identical, despite the geographic diversity of the isolates. As expected, the dDDH values calculated for pairwise comparisons of the isolates and their apparent corresponding Bt serovar type strains were quite high (> 98%), however dDDH comparisons of the isolates with other serovar type strains were often surprisingly low (< 70%) and suggest unrecognized taxa within Bt and the Bacillus cereus sensu lato.

Plant-Microbes Interaction: Exploring the Impact of Cold-Tolerant Bacillus Strains RJGP41 and GBAC46 Volatiles on Tomato Growth Promotion through Different Mechanisms.

The interaction between plant and bacterial VOCs has been extensively studied, but the role of VOCs in growth promotion still needs to be explored. In the current study, we aim to explore the growth promotion mechanisms of cold-tolerant Bacillus strains GBAC46 and RJGP41 and the well-known PGPR strain FZB42 and their VOCs on tomato plants. The result showed that the activity of phytohormone (IAA) production was greatly improved in GBAC46 and RJGP41 as compared to FZB42 strains. The in vitro and in-pot experiment results showed that the Bacillus VOCs improved plant growth traits in terms of physiological parameters as compared to the CK. The VOCs identified through gas chromatography-mass spectrometry (GC-MS) analysis, namely 2 pentanone, 3-ethyl (2P3E) from GBAC46, 1,3-cyclobutanediol,2,2,4,4-tetramethyl (CBDO) from RJGP41, and benzaldehyde (BDH) from FZB42, were used for plant growth promotion. The results of the partition plate (I-plate) and in-pot experiments showed that all the selected VOCs (2P3E, CBDO, and BDH) promoted plant growth parameters as compared to CK. Furthermore, the root morphological factors also revealed that the selected VOCs improved the root physiological traits in tomato plants. The plant defense enzymes (POD, APX, SOD, and CAT) and total protein contents were studied, and the results showed that the antioxidant enzymes and protein contents significantly increased as compared to CK. Similarly, plant growth promotion expression genes (IAA4, ARF10A, GA2OX2, CKX2, and EXP1) were significantly upregulated and the ERF gene was downregulated as compared to CK. The overall findings suggest that both Bacillus isolates and their pure VOCs positively improved plant growth promotion activities by triggering the antioxidant enzyme activity, protein contents, and relative gene expressions in tomato plants.

Biodegradation of di-2-ethylhexyl phthalate by Bacillus firmus MP04 strain: parametric optimization using full factorial design.

Di-2-ethylhexyl phthalate (DEHP) is used as a plasticizer in making plastics and released from landfills. This study attempted to degrade DEHP using microbial isolates. Isolates of Bacillus spp. were tested for their efficacy in degrading DEHP. Degradation was assessed using liquid chromatography-mass spectrometry (LC-MS). The most efficient DEHP degradation was achieved by Bacillus firmus MP04, which has been identified as Bacillus firmus MP04. This strain was found to use DEHP as the sole source of carbon without carbon source supplementation. Full factorial design was used to optimize the conditions for DEHP degradation which revealed the suitability of pH 7, 5% salt concentration, 20 to 37°C temperature, and yeast extract as a nitrogen source. LC-MS elucidated the possible degradation mechanism via benzoic acid formation. However, prolonged incubation formed a typical compound denatonium benzoate due to reactions with other compounds. As maximum degradation was achieved in 4days, prolonged incubation is not suggested. It can be concluded that new strain Bacillus firmus MP04 is the most efficient strain among all the tested strains for DEHP degradation.

In Vitro Activity of Cefiderocol Compared to Other Antimicrobials against a Collection of Metallo-Beta-Lactamase-Producing Gram-Negative Bacilli from Southern Spain.

In this study, we aimed to comparatively evaluate the in vitro activity of cefiderocol versus other antimicrobials against a well-characterized collection of metallo-beta-lactamase (MBL)-producing Gram-negative bacilli (MBL-GNB) isolates from hospitals in Andalusia, Spain. We recovered 232 MBL-GNB from Andalusian hospitals, including 160 Enterobacterales and 72 nonfermenting Gram-negative bacilli belonging to 44 different clones (2015 to 2020). Cefiderocol and comparator MICs were determined with commercial methods (UMIC [Bruker] and EUMDROXF [Sensititre; Thermo Fisher], respectively). EUCAST breakpoints were used for all antimicrobials tested, and CLSI also was used for cefiderocol. Control strains used were E. coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. Cefiderocol showed potent in vitro activity against isolates tested, regardless of breakpoint (susceptibility rates, 85.3% for EUCAST versus 96.6% for CLSI, P < 0.001). MIC ranges for Enterobacterales and nonfermenting Gram-negative bacilli (NF-GNB) were ≤0.03 to 1 mg/L and 0.06 to 2 (IMP), 0.06 to 8 mg/L and 0.06 to 16 (VIM), 0.25 to 16 mg/L and 2 to 16 mg/L (NDM), respectively, and 0.25 to 8 mg/L for double MBL-producing Enterobacterales. By species, all cefiderocol-susceptible rates were over 90%, except Klebsiella oxytoca, Enterobacter cloacae, Escherichia coli, and Acinetobacter spp. Significant differences were observed comparing resistant isolates between Enterobacterales and NF-GNB by EUCAST (19.4% versus 4.2%, P < 0.01), but not by CLSI (4.4% versus 1.4%, P = 0.2). Cefiderocol was the most active antimicrobial tested. Cefiderocol showed excellent in vitro activity against MBL-GNB, especially NF-GNB; almost all isolates resistant to comparators were susceptible. IMPORTANCE This article demonstrates the efficacy of cefiderocol against a large collection of well-characterized metallo-beta-lactamase-producing isolates, some of them even producing double carbapenemases. Furthermore, cefiderocol activity is compared to other novel broad-spectrum antimicrobials with activity against carbapenemases.

Bioaugmentation Approach using Pseudomonas and Bacillus for Malodour Reduction in Poultry Feacal Waste Management

Introduction. A workable strategy is bioaugmentation, which involves introducing certain bacteria in sufficient quantities to promote biodegradation. This study focuses on isolating and utilizing malodor-reducing bacteria from fecal wastes obtained from a poultry farm in Ashi, Ibadan. Methods. Standard methods were employed to isolate and identify species of Pseudomonas and Bacillus. Quantitative detection of hydrogen sulfide gas and other relevant parameters was performed using MSA Orion and Multi Gas Detector. Hydrogen sulfide (H2S) release was quantitatively monitored during fermentation, considering varying loads of inocula. Results. The bacterial isolates comprised Pseudomonas aeruginosa, P. fluorescens, P. putida, Bacillus fastidiosus, B. licheniformis, B. megaterium, B. subtilis, B. sphaericus, and B. thuringiensis. Odor levels varied based on inocula load and fermentation duration. In batches with Pseudomonas, hydrogen sulfide was undetectable after two days, while Bacillus-inoculated batches required ten days. The formation of microbial mats and subsequent decrease in H2S content contributed to malodor reduction. Notably, fluorescent pseudomonas exhibited successful mineralization during the treatment of fecal waste. Conclusion. Pseudomonas isolates demonstrated superior effectiveness in odor reduction compared to Bacillus isolates.

The effects of microcapsules with different protein matrixes on the viability of probiotics during spray drying, gastrointestinal digestion, thermal treatment, and storage

AbstractThe objective of this research was to encapsulate probiotic bacteria based on the protein matrix and investigate the influences on the survival of probiotic bacteria during spray drying, in vitro gastrointestinal digestion, heating, and storage. A probiotic isolate Bacillus coagulans BC01 was spray dried in whey protein isolate (WPI), soy protein isolate (SPI), camel whey protein isolate, or sodium caseinate. Probiotic microcapsules fabricated using WPI obtained the highest survival during spray drying, NaCl and paraxin challenges and storage, as less cell wall damage occurred during spray drying which could be observed by flow cytometer. However, the highest survivals during in vitro gastrointestinal digestion and thermal treatment were found in microcapsules with SPI matrix, which could be attributed to its relatively low solubility in water that prevented probiotics from being released prematurely, thus protecting probiotics from the damage of low pH environment and diminishing the direct contact of cells with external heat shock. In conclusion, the current study demonstrated that WPI‐based probiotic microcapsules with less cell wall damage during processing and SPI‐based probiotic microcapsules with relatively low solubility may provide better protection to adverse external environments.

Screening and Optimization Consortium Technique of the Bacillus megatherium and Saccharomyces cerevisiae Microbial Consortium for Ethanol Detection

Determination of alcohol content is very important in the food and beverage industry. Biosensor is an alternative to measuring ethanol content. Alcohol biosensors with a single microbe still have a narrow measurement area at ethanol concentrations, so a microbial consortium is needed to widen the range of measured ethanol concentrations. Therefore, it is necessary to screen the microbes from Bacillus sp and S. cerevisiae which have the potential to produce alcohol dehydrogenase (ADH) enzymes and optimize the consortium technique that can provide the best response to oxidation currents. In the yeast microbial screening of 14 S. cerevisiae isolates and 5 Bacillus sp isolates, it can be concluded that for the 14 yeast S. cerevisiae isolates that have the potential to produce ADH enzymes, there is one isolate with the SCRF code. For the 5 bacterial isolates of Bacillus sp that have the potential to produce ADH enzymes, all Bacillus isolates with the code Bacillus megatherium 29/9/14, Bacillus megatherium 23/6/22, Bacillus 6, Bacillus 53, and Bacillus 55. Based on the oxidation current data, Bacillus megatherium 23 /6/22 produces the highest current compared to other Bacillus isolates. The consortium technique that provides the highest current is the method of mixing 1:1 (µL) microbial suspension in an Eppendorf container. Optimization of the consortium's biofilms using the Response Surface Method was produced at 10 days of age, pH 7.5, and 75 µL of microbial suspension dripping volume.