1 00:00:06,791 --> 00:00:11,044 What if I told you there were trillions of tiny bacteria all around you? 2 00:00:11,044 --> 00:00:12,523 It's true. 3 00:00:12,523 --> 00:00:16,622 Microorganisms called bacteria were some of the first life forms 4 00:00:16,622 --> 00:00:18,262 to appear on Earth. 5 00:00:18,262 --> 00:00:20,857 Though they consist of only a single cell, 6 00:00:20,857 --> 00:00:25,811 their total biomass is greater than that of all plants and animals combined. 7 00:00:25,811 --> 00:00:29,071 And they live virtually everywhere: 8 00:00:29,071 --> 00:00:33,555 on the ground, in the water, on your kitchen table, on your skin, 9 00:00:33,555 --> 00:00:35,945 even inside you. 10 00:00:35,945 --> 00:00:38,276 Don't reach for the panic button just yet. 11 00:00:38,276 --> 00:00:42,096 Although you have 10 times more bacterial cells inside you 12 00:00:42,096 --> 00:00:46,293 than your body has human cells, many of these bacteria are harmless 13 00:00:46,293 --> 00:00:50,738 or even beneficial, helping digestion and immunity. 14 00:00:50,738 --> 00:00:54,895 But there are a few bad apples that can cause harmful infections, 15 00:00:54,895 --> 00:00:58,093 from minor inconveniences to deadly epidemics. 16 00:00:58,093 --> 00:01:04,221 Fortunately, there are amazing medicines designed to fight bacterial infections. 17 00:01:04,221 --> 00:01:08,128 Synthesized from chemicals or occurring naturally in things like mold, 18 00:01:08,128 --> 00:01:13,975 these antibiotics kill or neutralize bacteria by interrupting cell wall synthesis 19 00:01:13,975 --> 00:01:18,276 or interfering with vital processes like protein synthesis, 20 00:01:18,276 --> 00:01:21,062 all while leaving human cells unharmed. 21 00:01:21,062 --> 00:01:24,454 The deployment of antibiotics over the course of the 20th century 22 00:01:24,454 --> 00:01:27,974 has rendered many previously dangerous diseases easily treatable. 23 00:01:27,974 --> 00:01:30,871 But today, more and more of our antibiotics 24 00:01:30,871 --> 00:01:32,987 are becoming less effective. 25 00:01:32,987 --> 00:01:35,588 Did something go wrong to make them stop working? 26 00:01:35,588 --> 00:01:40,447 The problem is not with the antibiotics but the bacteria they were made to fight, 27 00:01:40,447 --> 00:01:44,587 and the reason lies in Darwin's theory of natural selection. 28 00:01:44,587 --> 00:01:49,620 Just like any other organisms, individual bacteria can undergo random mutations. 29 00:01:49,620 --> 00:01:53,235 Many of these mutations are harmful or useless, 30 00:01:53,235 --> 00:01:56,479 but every now and then, one comes along that gives its organism 31 00:01:56,479 --> 00:01:59,065 an edge in survival. 32 00:01:59,065 --> 00:02:01,745 And for a bacterium, a mutation making it resistant 33 00:02:01,745 --> 00:02:05,208 to a certain antibiotic gives quite the edge. 34 00:02:05,208 --> 00:02:08,000 As the non-resistant bacteria are killed off, 35 00:02:08,000 --> 00:02:11,374 which happens especially quickly in antibiotic-rich environments, 36 00:02:11,374 --> 00:02:13,904 like hospitals, there is more room and resources 37 00:02:13,904 --> 00:02:17,884 for the resistant ones to thrive, passing along only the mutated genes 38 00:02:17,884 --> 00:02:19,722 that help them do so. 39 00:02:19,722 --> 00:02:22,352 Reproduction isn't the only way to do this; 40 00:02:22,352 --> 00:02:26,596 some can release their DNA upon death to be picked up by other bacteria, 41 00:02:26,596 --> 00:02:29,182 while others use a method called conjugation, 42 00:02:29,182 --> 00:02:32,459 connecting through pili to share their genes. 43 00:02:32,459 --> 00:02:38,293 Over time, the resistant genes proliferate, creating entire strains of resistant super bacteria. 44 00:02:38,293 --> 00:02:43,109 So, how much time do we have before these superbugs take over? 45 00:02:43,109 --> 00:02:46,736 Well, in some bacteria, it's already happened. 46 00:02:46,736 --> 00:02:50,376 For instance, some strands of staphylococcus aureus, 47 00:02:50,376 --> 00:02:54,181 which causes everything from skin infections to pneumonia and sepsis, 48 00:02:54,181 --> 00:02:57,465 have developed into MRSA, becoming resistant to 49 00:02:57,465 --> 00:03:02,326 beta-lactam antibiotics, like penicillin, methicillin, and oxacillin. 50 00:03:02,326 --> 00:03:04,598 Thanks to a gene that replaces the protein 51 00:03:04,598 --> 00:03:07,401 beta-lactams normally target and bind to, 52 00:03:07,401 --> 00:03:10,860 MRSA can keep making its cell walls unimpeded. 53 00:03:10,860 --> 00:03:13,909 Other super bacteria, like salmonella, 54 00:03:13,909 --> 00:03:17,079 even sometimes produce enzymes like beta-lactams 55 00:03:17,079 --> 00:03:20,702 that break down antibiotic attackers before they can do any damage, 56 00:03:20,702 --> 00:03:25,047 and E. coli, a diverse group of bacteria that contains strains that cause 57 00:03:25,047 --> 00:03:28,185 diarrhea and kidney failure, can prevent the function 58 00:03:28,185 --> 00:03:31,033 of antibiotics, like quinolones, by actively booting 59 00:03:31,033 --> 00:03:34,566 any invaders that manage to enter the cell. 60 00:03:34,566 --> 00:03:36,392 But there is good news. 61 00:03:36,392 --> 00:03:39,610 Scientists are working to stay one step ahead of the bacteria, 62 00:03:39,610 --> 00:03:43,087 and although development of new antibiotics has slowed in recent years, 63 00:03:43,087 --> 00:03:47,988 the World Health Organization has made it a priority to develop novel treatments. 64 00:03:47,988 --> 00:03:51,273 Other scientists are investigating alternate solutions, 65 00:03:51,273 --> 00:03:55,784 such as phage therapy or using vaccines to prevent infections. 66 00:03:55,784 --> 00:03:59,621 Most importantly, curbing the excessive and unnecessary use of antibiotics, 67 00:03:59,621 --> 00:04:02,684 such as for minor infections that can resolve on their own, 68 00:04:02,684 --> 00:04:06,344 as well as changing medical practice to prevent hospital infections, 69 00:04:06,344 --> 00:04:10,360 can have a major impact by keeping more non-resistant bacteria alive 70 00:04:10,360 --> 00:04:13,082 as competition for resistant strains. 71 00:04:13,082 --> 00:04:16,840 In the war against super bacteria, deescalation may sometimes work better 72 00:04:16,840 --> 00:04:19,625 than an evolutionary arms race.