Prevalence and Characterization of Staphylococcus aureus in Growing Pigs

Prevalence and Characterization of Staphylococcus aureus in Growing Pigs

Summary

Staphylococcus aureus (SA) is a symbiotic and opportunistic pathogen affecting man and other homoeothermic species. The clinical manifestation of S. aureus infection in humans ranges from minor superficial skin lesions to extreme and sometimes fatal invasive infections. More than 30 percent of people have S. aureus. Although it does not harm the host, the pathogen can lead to other diseases.  This article states that S. aureus has shown a high capacity to act to novel antibiotics since the antimicrobial era. Instead, the pathogen has acquired resistance determinants like methicillin-resistance strains (MRSA) amid the introduction of that drug for medical purposes.

Human MRSA infections before 1995, occurred mainly in hospitalized patients who got the disease nosocomially. Since 2004, several reports of MRSA in animals raised concerns about animal-to-human transmission. One particular example is the prevalence of ST389 clonal complex strains (known as livestock-related MRSA’ or LA-MRSA) discovered from nasal swabs from animals like cattle and pigs. Due to limited information about these pathogens in the U.S. swine industry, a study was done on samples from farmworkers and pigs on antibiotic-free swine and ordinary farms in many states in the U.S.

Discussion of the Science

The reason for carrying out this investigation was to inspect the prevalence of MRSA in swine and swine employees in two swine cultivating zones Illinois and in Iowa. When the research was ongoing, it was noted that several swine and swine farmers in Canada and the Netherlands had MRSA. Still, this kind of study had not been carried out in the U.S. The investigation used several materials and strategies. Weaned pigs aged six and eighteen weeks were used as samples.

On the other hand, all farmworkers in the two swine producing states in the U.S. also wanted to be involved in the study. The sample size within these states was sufficient to detect a positive herd. The farms were selected based on the willingness of the owners to participate in the study. During this study, veterinarians obtained nasal swabs from pigs 299 swine nostrils and twenty laborers after submitting a written informed consent. More than 80000 live animals occupied the two farms.

Through sample gathering and bacterial confinement, one nostril from every animal and the nostrils of caretakers were tests with sterile swabs. For all the samples obtained from the swabs to be transported correctly, they were embedded into Stuart’s medium, which was set a four degrees Celsius. Samples were after that immunized into 2 mL of enhancement stock that had 10g of tryptone/L, 75g of mannitol/L, and 2.5g of extracted yeast/L. Following 24 hours of brooding at 35 degrees Celsius, a loopful of soup was immunized onto particular MRSA agar plates. Incubation was then done to the plates for a period of one to two days at 35 degrees Celsius and inspected for MRSA. To find out the samples which had MRSA, an affirmation test to check the appearance of the isolates was conducted on a gram stain. Methicillin resistance was affirmed by testing for the existence of penicillin restricting protein 2. The MRSA isolates distinguished were then kept at -80 degrees Celsius for them to be viable (Smith et al., 2009).

Molecular typing was selected as a suitable method to isolate all humans, and fifteen secludes from the swine. Pulse field gel electrophoreses (PFGE) were conducted on the isotopes (Smith et al., 2009). In a laboratory setting, scientists used PFGE to deliver a DNA unique finger impression for a bacterial isolate, which is MRSA in this case (CDC, 2016). Eagl was used on isolates, which were non-type capable after Smal absorption. Isolates from this investigation were contrasted and different kinds of strains. For staphylococcal cassette chromosome, mec composing and Panton-Valentine leukocidin (a gene located in staphylococcus) gene detection and genomic DNA were removed utilizing the Wizard Genomic DNA arrangement pack. An additional polymerase chain reaction test determined the presence of Panton-Valentine Leukocidin. Multilocus sequence typing, the process of typing multiple loci, was conducted on a section of isolates that were indistinguishable by PFGE. The entirety of the molecular testing systems utilized known negative and positive controls (Smith et al., 2009)

According to the study, it was evident that MRSA can spread from animals to humans. This colonization is linked to the application of tetracycline in swine farms. In all the human MRSA isolates from which the fifteen swine isolates that were assessed by molecular composing, they were likewise examined for antimicrobial sensitivity by the stock weakening strategy. For stock weakening, microscopic organisms are immunized into a fluid development medium within sight of various convergences of an antimicrobial specialist. Development is evaluated after incubation for a characterized timeframe, and the negligible inhibitory concentration value is determined (Wiegand, Hilpert, and Hancock, 2008). The isolates were examined for susceptibility to14 antibiotics to include penicillin and tetracycline (Smith et al., 2009).

Lastly, researchers used to survey and data analysis as their last method in this study. Laboratory and questionnaire data were associated with every specimen under investigation. Possible Potential risk affiliations were evaluated with Fisher’s accurate test, while bivariate and multivariate demonstrating of risk factors were performed by careful strategic relapse. The Cochran-Armitage trend test was then used to distinguish inclines in the pervasiveness of MRSA in swine by age. The prevalence rates for swine MRSA positive (+) and the linked 95 percent confidence was fixed for clustering to reflect the uncertainty around estimates. All the data for this study was done using SAS version 9.3.

The findings from the study were pretty outrageous. Overall, swabs were drawn from 299 swine from 7 distinguished ages. The overall susceptibility of MRSA was 49%, with the younger pig showing a higher risk of being infected with bacteria. Out of the swine facility workers that were tested, 45% carried MRSA (Yong, 2009). Veterinarians discovered that all the isolates from the swine and the humans were not compatible with oxacillin, penicillin, and tetracycline. They were found susceptible to 8 of the 14 antibiotics, and the isolates showed differing results in resistance and susceptibility to the other three antibiotics (Smith et al., 2009). These findings are significant because they suggest that MRSA can be spread easily and readily between pigs and humans and may have substantial impacts on the epidemiology of the MRSA infection (Smith et al., 2009).

Reports on the severity of fatal systematic infection show that S. aureus characters of the ST398 family can be a threat to human pathogens. However, reports, especially from Europe, have not clearly stated clinical infections from screening and culture (+) swabs and the specific risks of colonization due to livestock interaction. Certain types of ST398 are represented more in humans’ isolates than livestock isolates. This means different ST398 subtypes differ in the way they colonize humans and cause diseases.

There are plans to conduct more research in future to examine risks s of the MRSA infection among swine workers a close to them. Massive surveillance of retail meat products for MRSA contamination should be launched too in future. Larger populations of humans and swine must be studied to establish the epidemiology of MRSA within swine activities and evaluate the rates of MRSA in other animals (Smith et al., 2009).

Opinion

            I think that this study was very detailed. The tests done did a lot to determine how easily MRSA can spread not just between communities, but also between species. The way that the scientists explained how the samples were stored and transported showed that they were careful as to not ruin the samples. Carrying out tests at two separate facilities and between seven different age groups gave the study a wide range of possibilities and yielded more pertinent information, such as the younger pigs being more likely to contract the disease. If there were any faults, I think that they could have tested a larger geographical range. Maybe they could have tested facilities on the east coast and west coast, but I’m not sure how prevalent pig farms are outside of the middle of the country.

Also, the application of the broth dilution method in this study to determine antibiotic susceptibility is antiquated. Broth dilution method was invented in 1960 as indicated by Michael Mahan, a professor of Microbiology at the University of California, Santa Barbara, using this method to detect antibiotic-susceptibility does not seem right because it is up to date. A lot of bacteria and pathogens keeps on emerging day after day. Therefore a method that worked well in the ‘70s or ‘80s may not be effective in 2010 (Mercola, 2015). This is why, in the article by (dcyb nddkj ce) the potential risk factors observed among the PSA staff regarding MRSA was hard to explain where they were carriers or not. Stanley Maloy, former president of the American Society for Microbiology also stated that, “It’s really clear that there key examples where the way we’ve been doing things up until now is probably inadequate” (Mercola, 2015).

In general, the information provided from the results, together with more modern processes, can also help to find what type of antibiotic is appropriate against the MRSA. If the studies will be utilized properly, they will help health care organizations to be more effective in treating patients that have contracted the disease. The studies that will come immediately after this will be critical because up to date procedures and methods will be incorporated. I will be fascinated to view their outcomes and how they will be used to identify risk factors presented by the disease.

Real-World Application

            The real-world applications of this study are most applicable to the future treatment and prevention of MRSA. Due to the overuse of antibiotics in livestock to promote growth, bacteria, such as MRSA, are becoming increasingly resistant to antibiotics (Mercola, 2015). Studies like this have shown that it is necessary to for the medical world to not only determine the genetically based resistance mechanisms of MRSA, but also to continue to study the origins and habitats of resistant bacteria (Schmithausen et al., 2015). I believe that through studies like this one we will see improved infection prevention, more responsible use of antibiotics, and new ways to treat infections. I also hope and believe that through these types of studies we will see more effective laws and regulations to limit overuse of antibiotics in medicine and farming. In the recent years, the emergence of new antibiotic resistant bacteria have been born. With this laws in action, measures will be taken at farm level to avoid the reborn of controlled bacteria. Through the quantification of LA-MRSA organisms, farmers will be provided with critical information that will help them to evaluate colonization versus contamination events and aid in informing evaluation of associated health impacts.