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Due to the rising cost of commercial potable water, residents - especially in rural areas - increasingly rely on artesian well water, which is usually untreated and not regularly tested for potability. This could lead to a higher risk of ingestion of microorganisms exhibiting resistance to antibiotics. Thus, this study focused on detecting fecal coliforms - specifically Escherichia coli - from artesian well water samples from selected barangays (Bayog, Malinta, and Mayondon) in Los Baños, Laguna, the Philippines. Isolated E. coli were screened for antimicrobial resistance. Out of 30 water samples, eight were presumptively positive for coliforms, as determined using the multiple-tube fermentation method. Three out of eight samples (MY2-2, ML2-3, and ML2-4) obtained E. coli isolates, as identified through phenotypic and molecular characterization. Using disk diffusion assay, resistance patterns were identified in the isolates for antibiotics cefoperazone, meropenem, ofloxacin, and trimethoprim sulfamethoxazole. Results revealed that MY2-2 was resistant to cefoperazone, meropenem, and trimethoprim sulfamethoxazole; ML2-3 was resistant to cefoperazone and meropenem, whereas ML2-4 was resistant to all four antibiotics. Polymerase chain reaction with primers detecting the TEM gene, which is a type of extendedspectrum ß-lactamase gene, showed that the isolates were resistant to ampicillin and penicillin. Results of phenotypic and molecular methods indicate that the isolates are multi-drug resistant. Based on household interviews, the artesian well water from which MY2-2 was isolated, was used for drinking by 10 households. Therefore, the local government units should regularly monitor artesian well water for microbiological quality, conduct education and information campaigns on the diseases that can be contracted from consuming unclean water, and ensure that potable water is accessible, especially for households with no access to purified water. [ABSTRACT FROM AUTHOR]

A cyclodextrin glucanotransferase (CGTase)-producing bacterium was isolated from Manleluag hyperalkaline spring, Pangasinan, the first to be reported from a hyperalkaline environment in the Philippines. The isolate, M136, had the highest CGTase enzyme activity (46.01 U/mL) out of the forty-one similar bacterial isolates and exceeds the CGTase activity of the reference strain, Paenibacillus sp. JCM 9143. Using whole genome analysis, M136 was identified as Alkalihalobacillus lehensis. The CGTase enzyme produced by Alkalihalobacillus lehensis M136 was partially purified with 73.97% recovery and post-purification activity of 49.52 U/mL. The enzyme has an estimated molecular weight of 78.64 kDa and an isoelectric point of 4.72. Enzyme characterization revealed that it was stable at 30-80 °C (optimal activity at 70 °C), pH 4.0-10.0 (optimal activity at pH 6.0), and in the presence of different metal ions and reagents such as zinc, calcium, magnesium, and manganese, ethylenediaminetetraacetic acid, iodoacetic acid, sodium dodecyl sulfate, and phenylmethylsulfonyl fluoride. [ABSTRACT FROM AUTHOR]

The antimicrobial activity of the ethanol extract of propolis (EEP) from the stingless bee, Tetragonula biroi Friese, was screened for activity against Escherichia coli, Pseudomonas aeruginosa,Bacillus cereus,Candida krusei, Staphylococcus aureus, and Penicillium chrysogenum using the disk diffusion method and agar-well assay. The highest inhibitory activities of EEP was observed at 30% (w/v) against Bacillus cereus (12.78 ± 1.92 mm), followed by Staphylococcus aureus (10.22 ± 0.83 mm), Penicillium chrysogenum (13.33 ± 2.40 mm), and Candida krusei (6.00 ± 0.00 mm) compared to the other concentrations – 10% (v/v) and 20% (v/v) of EEP. The antimicrobial activity of 30% w/v EEP against P. chrysogenum and C. krusei was comparable to mycostatin at 13.67 ± 0.58 and 6.33 ± 0.58 mm, respectively. The EEP was found to have no effect on Escherichia coli and Pseudomonas aeruginosa. Considered as a natural product, propolis has the potential to be a substitute for synthetic antimicrobial compounds commonly used in commercial products such as soaps. [ABSTRACT FROM AUTHOR]

This study investigated the potential bacteriocinogenic property of E. coli isolates against two EHEC strains using the Deferred Growth Inhibition, Spot-on-Lawn, and Bacteriocin Sensitivity Assays, in the search for new antimicrobials against some pathogenic E. coli serotypes. Among 62 E. coli strains evaluated (sourced from native and commercial chickens, and from bat guano through UPLB-MNH), only MNH strains 1647, 1648, 1651, and 1652 showed antagonistic activity against the EHEC strains in the Deferred Assay. In the Spot-on-Lawn Assay, none of the preparations from the four isolates heated at 90'C for 10 minutes inhibited the test strains suggesting heat sensitivity of the inhibitory substance, similar to many bacteriocins. In the Bacteriocin Sensitivity Assay, only MNH 1647 and 1651 inhibited another E. coli strain (DH5a) on LB Agar, with or without the stress inducer Mitomycin C. Significantly bigger zones of inhibition relative to the controls were observed with sonicated cell and cell-free supernatant preparations of the isolates treated with Mitomycin C. This study proved that bat guano E. coli could be potential sources of putative bacteriocins/bacteriocin-like substances against some EHEC strains and that Mitomycin C seemed to enhance the putative bacteriocinogenic activity of preparations from the bat guano isolates. [ABSTRACT FROM AUTHOR]

The Mount Makiling Forest Reserve (MMFR) is a biodiversity hotspot and listed as one of the 170 conservation priority areas established by the Philippine government. Its flora and fauna diversity has been reported, but knowledge gap has been identified concerning the bacterial communities associated with the flora and fauna. This study focused on ants (Hymenoptera: Formicidae), which are dominant in forest canopy and play essential roles in the ecosystem functionality. A metagenomic sequencing approach based on amplified V3-V4 regions of the 16S rRNA was employed to investigate the bacterial communities associated with five arboreal ant species collected from MMFR. The collected ants were identified as Dolichoderus thoracicus, Myrmicaria sp., Colobopsis leonardi, Polyrhachis mindanaensis, and Polyrhachis semiinermis. The sequence analyses revealed that Proteobacteria, Spirochaetes, Firmicutes, Bacteroides, and Actinobacteria were the most abundant phyla. Individual analysis of the bacterial genera associated with the five ant species showed that unclassified members of Rhizobiaceae, Orbaceae, and Burkholderiaceae were dominant in D. thoracicus. Unclassified members of Rhizobiaceae, Spirochaetaceae, and Ruminococcaceae were dominant in Myrmicaria sp. On the other hand, Candidatus Blochmannia, and Wolbachia were abundant in Camponotini ants C. leonardi, P. mindanaensis, and P. semiinermis. Bray-Curtis distance and UPGMA cluster analyses showed that the microbiomes of the Camponotini group clustered together, while D. thoracicus and Myrmicaria sp. exhibited unique bacterial profiles. Predictive gene profile analysis showed that the most functional categories were those associated with metabolism and biosynthesis of amino acids, pathways for metabolism of nucleotide, amino sugars and nitrogen, and utilization of different carbon sources. [ABSTRACT FROM AUTHOR]