Highly-polluted surface waters are increasingly used for irrigation in different agricultural settings because they have high nutrient content and are readily available. However, studies showed that they are reservoirs for the emergence and dissemination of antibiotic-resistant bacteria in the environment. In this study, the resistance of 212 Escherichia coli isolates from irrigation water, soil, and vegetables in selected urban farms in Metro Manila, Philippines was evaluated. Results showed that antibiotic resistance was more prevalent in water (67.3%) compared to soil (56.4%) and vegetable (61.5%) isolates. Resistance to tetracycline was the highest among water (45.6%) and vegetable (42.3%) isolates while ampicillin resistance was the highest among soil isolates (33.3%). Multidrug-resistant (MDR) isolates were also observed and they were more prevalent in water (25.3%) compared to soil (2.8%) and vegetable (8.4%) isolates. Interestingly, there are patterns of antibiotic resistance that were common to isolates from different samples. Extended-spectrum beta-lactamase production (ESBL) was also investigated and genes were observed to be present in 13 isolates. This provides circumstantial evidence that highly-polluted surface waters harbor antibiotic-resistant and MDR E. coli that may be potentially transferred to primary production environments during their application for irrigation purposes.

Contaminated irrigation water may greatly affect not only the quality of produce but also the people exposed to it. In this study, agricultural irrigation waters in Bulacan, Philippines were assessed and found to be contaminated with Escherichia coli (E. coli) ranging from 0.58 to 4.51 log CFU/mL. A total of 79 isolates of E. coli were confirmed through polymerase chain reaction (PCR) amplifying the uidA gene and were tested for phenotypic resistance using 10 antimicrobials through the Kirby-Bauer disc diffusion method. Forty-six isolates (58.22%) were noted to be multidrug resistant (MDR) with high resistance rate to cephalothin, tetracycline, streptomycin, ampicillin, trimethoprim, nalidixic acid, and chloramphenicol. Moreover, this study also examined the prevalence of Class I and II integrons accounting to 67.39% and 17.39%, respectively, of the MDR E. coli strains using multiplex PCR. The results imply that the agricultural water used in Bulacan is contaminated with the fecal material of man or other animals present in the area, and the presence of MDR bacteria, which pose a potential threat to individuals in these areas, is alarming. In addition, detection of integrons could be a good marker for the identification of MDR isolates. Lastly, this study could develop strategies for the proper management of farming sites leading to the detection of food-borne pathogens and prevention of infectious diseases.

Payatas landfill site is one of the major dumpsites in the Philippines. In this study, the landfill was evaluated regarding the presence and concentration of pathogenic bacterial aerosols through culture and molecular techniques. Bioaerosols are biological airborne particles that may or may not cause diseases. Active sampling was done using MAS-100 Air Sampler from both indoor and outdoor locations. To test the accuracy of the culture method, those that were presumptively identified as Staphylococcus aureus and Klebsiella pneumoniae were subjected to molecular analysis using 16s rRNA sequencing, and as a result, they were identified as different species. The exposure assessment done by interview showed matches among prevalent diseases. The results of this study can be used as a basis for creating standards and regulations for workers' and residents' safety and health in the landfill site.

The study aimed to assess the role of Pseudomonas aeruginosa (P. aeruginosa) biofilm in the development of antimicrobial resistance of Escherichia coli (E. coli). P. aeruginosa (ATCC 27853) and E. coli (ATCC 25922) were cultured on cetrimide agar and eosin methylene blue (EMB) agar. The two microorganisms were mixed to prepare three bacterial suspensions using tryptic soy broth (TSB) in increasing concentrations, such as: 1:1, 2:3 and 1.5:3.5. Bacterial suspensions were transferred into MBEC™ Assay kits which was subjected to agitation and incubated at 37°C for 24 hrs and 48 hrs. Formed biofilms on peg lids were obtained for Gram staining and cultured using EMB agar to evaluate the biofilm matrix and presence of bacteria. Polymerase chain reaction (PCR) was conducted to determine significant changes in E. coli genes that matched the Tn1696 aacC1, Tn10 tetRA and Tn903 aph resistance genes of E. coli which codes for gentamicin, tetracycline and kanamycin, respectively. Results showed strong bands to Tn1696 aacC1 gene for gentamicin resistance at the highest concentration. No bands were visualized for tetracycline and kanamycin resistance. The results therefore establish that coexistence of both organisms in a biofilm leads to the development of the antimicrobial resistance of E. coli to gentamicin.