Resistance of E Coli to Antibiotics - Case Study Example

Resistance of E.Coli to Antibiotics Resistance of E.Coli to Antibiotics Introduction Escherichia coli, commonly refered to as E.coli bacteria, is a gram-negative, facultative anaerobic bacteria that usually lives inside the intestines of healthy humans and animals and most strains are relatively harmless or cause brief diarrhea (Gao & Li 2010, p. 69). However, some can cause urinary tract infections, bloody vomiting or diarrhea, severe abdominal cramps and life-threatening infections of the bloodstream. On the other hand, antibiotics are a type of antimicrobials that work against bacteria by inhibiting their growth or killing them in the medicinal treatment of bacterial disease. However, even with the contribution of antibiotics towards efforts to eradicate certain diseases, the ease of access and effectiveness was counterproductive and resulted in bacteria developing resistance. Antibiotic resistance occurs when microbes acquire genetic mutations that render them resistant to the effects antibiotics that were previously effective. Recent studies have shown that the rate of resistance to antibiotics is increasing rapidly particularly with regards to third-generation and fourth-generation cephalosporins as well as fluoroquinolones (Nelson, J, Chiller, T & Powers, 2012, p. 980). It is also a surprising occurrence that most of the antibiotic-resistant strains are more commonly acquired in the community settings rather than the healthcare environment. People readily acquire antibiotic-resistant E. coli through their diet, especially undercooked meat and raw vegetables and that fact significantly impacts on the everyday turnover of the bacteria. On the other hand, when people consume sterile food, the numbers of the antibiotic-resistant E. coli they carry falls substantially and rapidly. The purpose of this paper is to discuss the recent strain of antibiotic-resistant E. coli from the perspective of natural occurrence, veterinary medicine and human medicine and also highlight other strains. Definition of E. Coli E. coli (Escherichia coli) is a gram-negative, facultative anaerobic bacterium that lives inside the intestines of health humans and animals. E. coli is normally a commensal bacterium of animals and humans and pathogenic variants have been known to cause both extraintestinal and intestinal infections such as septicemia, peritonitis, meningitis, urinary tract infection and gastroenteritis. The type of infection will generally determine the therapeutic option, for example, trimethoprim is a treatment of choice for urinary tract infection (Tadesse et al 2012, p. 1). On the other hand, it is not recommended to use antimicrobial drug therapy for E. coli infections that produce the Shiga toxin. Healthy adults will usually recover from O157:H7 E. coli infection within a week but older adults and younger children will be exposed to more risks of life-threatening kidney failure refered to as hemolytic uremic syndrome (Sodha, Lynch M & Wannemuehler 2011, p. 310). The use of E. coli to monitor resistance to antimicrobial drug therapy in fecal bacteria is appropriate because it is usually found in a wider range of hosts and easily acquires resistance. Definition of Antibiotics and how they Work Antibiotics are drugs used for the treatment of diseases or infections such as whooping cough, pneumonia and respiratory tract infections caused by bacteria (Pearson, Franklin & Bell 2010, p. 504). They can also be used for a wider range of bacterial infections that include infected wounds, skin infections and urinary tract infections. From their initial introduction in the 1940s, antibiotics have saved lives but their effectiveness on the bacteria they once fought is declining after being overused and misused (Abbeele & Verstraete 2013, p. 336). They work by inhibiting vital bacterial processes as well as stopping their multiplication hence helping the natural immune system of the body in the fight against bacterial infection. Antibiotics may be differentiated basing on the types of bacteria they are used against and those that affect a wide range, such as gentamicin and amoxicillin, are refered to as broad spectrum antibiotics (Hawkey & Jones 2009, p. 9). On the other hand, those that only affect smaller range of bacteria are refered to as narrow spectrum antibiotics and an example is penicillin. These different types also function in different ways. Penicillin, for example, destroys the walls of bacteria while others will affect the way in which the bacteria’s cell works (Nelson, J, Chiller, T & Powers, 2012, p. 977). The choice of antibiotics by doctors is usually based on the particular infection they cause and tests are also common to identify the exact bacteria type that has caused an infection as well as its sensitivity to specific antibiotics. Definition of Antibiotics Resistance According to the World Health Organisation (WHO), antibiotic resistance is the resistance of microorganisms to drugs that were previously able to treat the infections caused by the microorganisms (Arias & Murray 2012, p. 439). This can be understood to be the ability of bacteria to resist the effects of antibiotics that they were once sensitive to and such resistance happens when the bacteria change so as to protect themselves from the antibiotics. Once microorganisms develop resistance, antibiotics that would previously have killed then or stopped their multiplication no longer work. Before antibiotics came into use, the number of bacteria that were resistant was small, but the extensive use of antibiotics kicked off the process of evolutionary pressure and created the resistance in the bacteria (Walsh, C 2009, p. 211). Why Antibiotic Resistance is a Problem From its definition, antibiotic resistance happens when antibiotics can longer kill or inhibit the growth of bacteria, meaning the bacteria will continue multiplying even in the presence of antibiotics at therapeutic levels (Caldwell & Lindberg 2011, p. 94). When antimicrobials were discovered in the 1940s, it was prophesied that infectious diseases that were increasingly overwhelming humankind would be defeated. On the contrary, the extraordinary healing capabilities of the antibiotics attracted not only widespread but also inappropriate use, overuse and misuse that resulted in resistance by bacteria and the consequential complications in treatment and escalating healthcare costs (Kennedy, Roberts & Collignon 2012, p. 209). The resistance to antibiotics has negated the possibilities of medical milestones taken for granted and undermined public health and clinical programs designed to control infectious diseases. Essentially, when people use antibiotics when they do not need them may imply that they will not work when needed in future (Guilfoile 2009, p. 21). Therefore, when one gets a bacterial infection that is resistant to antibiotics, the infection will persist longer with higher possibilities of developing further complications. Further, the infection could also be passed on to others hence compounding the problem. If the resistance to antibiotics continues spreading at its current rate, the modern interconnected world will be exposed to the risk of getting back to the dark ages of medicine when the power of antibiotics had not even been discovered (Laupland, Church & Pitout 2011, p. 441). Factors Contributing to the Increasing Resistance Resistance to antibiotics by bacteria is a key concern of the overuse of the antibiotics and bacteria can become resistant by mutating their genes after coming into contact with the antibiotics. Such changes will enable the bacteria to resist antibiotics and survive in their presence. It has also been shown from research that bacteria can develop resistance by coming into contact with other bacteria as resistant bacteria will pass their genes to others and in the process form new resistant strains. The more people use antibiotics, the higher the chances of bacteria developing resistance to them. The ever-increasing use of antibiotics is the underlying factor promoting resistance, with the global availability increasing since the 1950s (Nelson, J, Chiller, T & Powers, 2012, p. 978). Most middle and low income developing countries do not control the sale of antibiotics and they are easily available without requiring prescriptions and are characterised by limited access to effective treatments. Self-medication is a common practice since there is limited medical care and the availability of counterfeit drugs has contributed towards the increasing resistance. This creates the risk of using antibiotics even when the use is not indicated and, consequently, leading to the emergence of resistance in whatever bacteria that remains. Further, when wide-spectrum antibiotics are prescribed, they have more potential of inducing resistance than the narrow-spectrum ones. When people use antibiotics in doses and times that were not recommended by their doctors, they allow the bacteria in their systems time to develop resistance (Ton & Frenkel 2013, p. 127). In the developed countries, the use of antibiotics in animal feed to enhance growth is widely accepted but the negative consequence is that such use promotes resistance. Infections acquired from nursing home, hospital and community settings are a key source of illness and death. It has also been shown by studies that large quantities of antibiotics are released into the environment in the manufacturing process of pharmaceutical products since the waste water is not treated adequately (Abbeele & Verstraete 2013, p. 335). This greatly contributes to the creation of strains that are resistant to antibiotics. Antibiotic Resistant E. Coli Research has shown that a single antibiotic-resistant strain of E. coli has been the main cause of bacterial infection over the past decade among the elderly and women around the world (Abbeele & Verstraete 2013, p. 337). The “H30-Rx” strain has not only developed increasing resistance to antibiotics but also the extraordinary ability to spread to the bloodstream from the urinary tract and cause the extremely dangerous sepsis infection (Abbeele & Verstraete 2013, p. 337). This is a direct implication that in the US alone, over 10 million persons who acquire an infection of the urinary tract are exposed to sepsis by the “H30-Rx” strain each year (Johnson, Sannes & Croy 2009, p. 839). The increasing presence of antibiotic-resistant E. coli has rendered the treatment of infections more difficult and led to increased mortality and this particular strain has more ability than others to move into the bloodstream from the bladder and kidneys. From genetic analyses, it has been revealed that the strain came into being over 20 years ago when a strain then known as H30 developed mutations in two of its genes (Ton & Frenkel 2013, p. 129). The result was the clone known as H30-R that had resistance against the antibiotic Cipro. However, the H30-R further gave rise to H30-Rx that was not only resistant to Cipro but several other antibiotics, was particularly virulent and easily spread from person to person. Although studies have established that antibiotic-resistant E. coli are acquired from food and water, it still remains largely unclear where the bacteria in the food and water come from. This has raised questions as to whether human strains or those derived from food animals are responsible for contaminating what people consume. In an attempt to clarify the matter, Johnson, Sannes and Croy (2009, p. 838) analysed 287 isolates of E. coli that had been recovered from meat for a high figure of resistance markers and virulence factors. They were able to establish that antibiotic-resistant isolates were similar in characteristics to those of susceptible ones recovered from similar types of meat. However, they also found that they differed significantly from isolates recovered from other types of meat. Therefore, the antibiotic-resistant isolates found on products of retail poultry were very similar to the susceptible ones found on the same retail poultry products as was the case with the antibiotic-resistant and susceptible ones found on beef and pork products. This may imply that the antibiotic-resistant isolates found on poultry products are consequences of the use of antibiotics in poultry rather than the introduction of strains from other animals, humans or cross-contamination of meat after the poultry are slaughtered (Johnson, Sannes & Croy 2009, p. 839). Research findings have shown that resistance to antibiotics by E. coli remains consistently high for antimicrobial agents that have been used for the longest time in both veterinary and human medicine (Tadesse et al 2012, p. 1). For instance, the past 20 years have seen a major rise not only in the emergence but also spread of multi-drug resistant bacteria as will be shown in the two case studies below. There has also been an increase to the resistance to newer compounds including fluoroquinolones and some cephalosporins (Tadesse et al 2012, p. 1). The increasing resistance to antimicrobial agents that have been used for relatively longer periods was shown when E. coli isolates recovered from hospitals between 1971 and 1982 did not show major changes in their resistance to the tested antimicrobial agents. However and in contrast, an analysis on E. coli recovered from urine specimens from patients between 1997 and 2007 demonstrated an escalating trend of resistance to amoxicillin/clavulanic acid, trimethoprim/sulfamethoxazole and ciprofloxacin (Tadesse et al 2012, p. 1). Similarly, another follow-up study in Sweden for 30 years between 1979 and 2009 on E. coli showed there was an escalating trend of resistance to gentamicin, trimethoprim, sulfonamide and ampicillin. Researches on farms have linked multidrug-resistant E. coli to chronic exposure to antimicrobial drugs. Infections Associated with E. Coli Urinary Tract Infections (UTIs) The urinary tract forms the most common site of all the E. coli infections as over 90% of the UTIs, albeit uncomplicated, result from E. coli infection. The rate of recurrence following the first infection is usually 44% over a period of 12 months. E. coli infections to the urinary tract are caused by the strains refered to a uropathogenic strains. Nigerian Case Study Relatively few studies have been conducted to evaluate resistance to antibiotics in sub-Saharan Africa. However, between 1986, 1998, 11990, 1994 and 1998, tests were carried out on E. coli isolates recovered from apparently healthy Nigerian students to determine susceptibility to seven antibiotics (Okeke, Fayinka & Adebayo 2010, p. 842). It was established that for a 12-year period, strains resistant to streptomycin, tetracycline, chloramphenicol and ampicillin recorded prevalence rates ranging between 9% and 35% in 1986 to 56% and 100% in 1998 (Okeke, Fayinka & Adebayo 2010, p. 843). This also confirms earlier findings that antibiotic resistance is more prevalent in bacterial isolated recovered from subjects in developing countries and that normal intestinal flora serve as a reservoir for antibiotic-resistant genes. Further, strains of E. coli can exchange genetic material efficiently with pathogens such as Vibrio, Yersinia, Shigella, Salmonella and also pathogenic E. coli. The specimens for the study from the Nigerian students were collected into Stuart’s transport medium. They were then subcultured onto MacConkey agar plates and colonies showing morphologic attributes of E. coli subcultured onto fresh plates (Okeke, Fayinka & Adebayo 2010, p. 845). Susceptibility was tested using standard disk diffusion with tetracycline, trimethoprim, nalidixic, sulfisomidine, streptomycin, chloramphenicol and ampicillin antibiotic disks. The controls used were K-12 C600 and E. coli NCTC 10418 and all isolated recovered from the same student at the same time with identical antibiotic and biological susceptibility profiles were termed identical. The chi-square test and Pearson’s regression were used to analyse trends. Results showed that there was a trend of increasing resistance to antibiotics in E. coli specifically against streptomycin, chloramphenicol, ampicillin, sulfonamides and tetracycline. Between 1986 and 1998, the proportion of chloramphenicol-resistant isolates grew from 13.5% to 59.8% (Okeke, Fayinka & Adebayo 2010, p. 849). Of statistical significance, according to Okeke, Fayinka and Adebayo (2010, p. 849), were the trends for streptomycin and tetracycline (p Read More