A new research has shown that reusable water bottles carry 40,000 times more bacteria than an average toilet seat.

Researchers at US-based waterfilterguru.com conducted the study by examining four popular types of water bottles: spout, screw-top, stray, and squeeze-top.

The researchers swabbed different bottle parts and found how colony-forming units (CFUs) festered inside them. CFU is a unit used to determine the concentration of bacteria in any sample.

In their study, the researchers explained that while gram-negative bacteria can cause infections that are increasingly resistant to antibiotics, certain types of bacillus can result in gastrointestinal issues.

They majorly found two types of bacteria named gram-negative rods and bacillus. Gram-negative bacteria such as E. Coli and Klebsiella can cause serious infections such as pneumonia.

The infections caused by the bacteria are becoming increasingly resistant to antibiotics; meaning they are superbugs. Meanwhile, ingestion of bacillus can lead to nausea, vomiting, diarrhea, and gastrointestinal issues.

The scientists stated that to avoid drinking contaminated water, the bottles should be washed at least once a day with soapy water. Moreover, the bottles should be sanitised at least once a week

Further, the study revealed that squeeze-top bottles are the cleanest of the three styles tested, with a tenth of the amount of bacteria as one with a screw-top or straw-fitted lid.