Nasal Carriage Of Staphylococcus Aureus On Microbiology Students

Clinical Significance of Staphylococcus Aureus

Discuss about the Nasal Carriage of Staphylococcus Aureus on Microbiology Students.

The S.aureus species of bacteria together with the Methicillin Resistant Variant (MRSA) have a foundational niche of ecology in the nasal cavity of humans. However, it can invade the intestines and the perennial parts of the human body. S.aureus is among the major factors associated with health care and community –acquired infections. Commonly, S.aureus colonizes body sites such as device sites and open wounds, that is, the nose and the exposed skin areas. Some of the commonest infections associated with S.aureus include pneumonia, food poisoning, skin infections, Toxic Shock Syndrome (Otto, 2014) and blood poisoning which is also known as bacteremia (Tong, Davis, Eichenberger, Holland & Fowler, 2015).

The clinical significance of S.aureus is that its infections are dependent on the virulence of a particular bacteria strain, host immunity and size of the inoculum. Its infections are suppurative leading to abscesses containing damaged leukocytes and pus that are surrounded by necrotic tissue. Skin infections are the most prevalent of all the infections associated with S.aureus bacteria. These infections may be in form of pimples or boils. Sometimes, the infections are characterized by some pus or form of drainage which can be swollen, painful or reddish in color (Frank, Feazel, Bessesen, Price, Janoff & Pace, 2010).  These may sometimes shift to impetigo which is capable of changing into a skin crust. The skin infections due to S.aureus bacteria can attack anyone irrespective of factors such as age or location (Chen, Xie, Ni, Dai, Lu, Wu, & Huang, 2017).

The most significant and effective way of preventing infection due to staphs is keeping hands and wounds clean always. In most cases, the staphs are managed through infection drainage and use of antibiotics. There are some individuals who are at a higher risk of having the infections than others. Some of those at a higher risk include those with weak immunity, severe or chronic underlying illnesses such as diabetes, prolonged and recurrent exposure to antibiotics and invasive procedure such as catheterization and open wounds (DeLeo, Otto, Kreiswirth & Chambers, 2010).

Virulence factors of S.aureus play a crucial role in its pathogenicity. Enzymes like kinase, hemolysin, leucocidin and leukotoxins are key facilitators of the spread of the bacteria species in various body tissues and organs (Argudín, Tenhagen, Fetsch, Sachsenröder, Käsbohrer, Schroeter & Mendoza, 2011). Surface proteins such as capsule inhibit the phagocytic mechanism of the bacteria. Additionally, the biochemical proteins such as carotenoids and catalase promote the survival of the species in the phagocytes. Health Care -Associated MRSA differ from Community –Associated MRSA based on microbiology, epidemiology and clinical manifestations. CA-MRSA strains are regarded to be more susceptible to antibiotics since they contain csssete of chromosome type IV which produce a virulence factor called panton-Valentine leucocidin which causes soft tissue and skin infections to those who get invaded by MRSA (Argudín, Tenhagen, Fetsch, Sachsenröder, Käsbohrer, Schroeter & Mendoza, 2011).

Virulence Factors of Staphylococcus Aureus

Active surveillance for the students colonized with Methicillin Resistant Staphylococcus Aureus (MRSA) is the key recommendation in prevention of all infections associated with MSRA. Several research studies so far have reported on how prevalent MRSA nasal carriage is in health care settings (Halablab, Hijazi, Fawzi & Araj, 2010). Infection control multidisciplinary team in a local hospital in Delhi expressed much concern on the rising number of patients admitted to the hospital with MRSA colonization. Based on the high rate of admissions, it was suggested that the local community in Delhi might be having a high prevalence of MRSA (DeLeo, Otto, Kreiswirth & Chambers, 2010).

An MRSA survey was then undertaken aimed at screening health care workers and patients for MRSA nasal carriage, identifying risk factors of colonization of MRSA and determining their pattern of resistance. From this survey, it was concluded that Community Associated MRSA contributes to approximately 30% of infections associated with S.aureus in hospitals in Delhi. There is an urgency to study and research about S.aureus which is rapidly growing in communities and health centers (Tong, Davis, Eichenberger, Holland & Fowler, 2015).

The survey was conducted for more than 11 months between 2013 and 2017. The experiments which were performed involved nasal swabs from Microbiology Students at RMIT University who were considered to be generally healthy. The study included the students who voluntarily decided to participate in the survey and a one-time sampling of the participants was employed. The sample of microbiology students who participated in the study were all screened for Nasal Carriage of S.aureus after verbal consent had been obtained from them.

Specimens were collected using pre-moistened sterile cotton swabs from the anterior nares of the healthy students. Specimen inoculation was carried out with the aim of introducing a vaccine or an antigen to their bodies to produce a strong immunity for bacterial infections. The incubation of the inoculation was carried out in ambient air for a duration of 24-48 hours using sheep blood agar and mannitol salt (Lozano, Gómez-Sanz, Benito, Aspiroz, Zarazaga, M., & Torres, 2011).

Colonies which suggested S.aureus were white/ cream non-hemolytic or hemolytic yellow on Oxacillin Blood Agar and Mannitol Salt Agar. Catalase, gram stain, slide and tube coagulase tests were applied in identification of the S.aureus colonies. Confirmation of S.aureus isolates was done using disk confusion in accordance with the Clinical Laboratory Standards. Colonies of isolated presumptive of S.aureus were also confirmed after the discussion together with my survey demonstrator (Lozano, Gómez-Sanz, Benito, Aspiroz, Zarazaga, M., & Torres, 2011).

Prevention Measures Against Staphylococcus Aureus Infections

From the 662 microbiology students who were screened during the survey, 184 of the participants turned positive for S.aureus nasal carriage. The colonies that suggested S.aureus had a typical morphology on Mannitol Salt Agar, were Mannitol Positive, Catalase Positive and Gram-positive cocci with a typical morphology on microscopy. The ultimate confirmation of the survey findings was the tests on coagulase tests.

The table below show the coagulation tests results in percentage for the respective years when the screening was carried out:

Table 1.0

aureus nasal carriage rates of RMIT Students from 2013 to 2018

The findings for collective data were as tabulated below:

Table 2.0

Methicillin –resistant Staphylococcus Aureus (MRSA) has become the leading contributing factor of soft-tissues and skin disorders. Recent studies reports that infections associated with MRSA among the healthy individuals in community settings don’t have prior history of S.aureus bacteria (Rackham, Ray, Franks, Bielak & Pinn, 2010). This survey discovered that 184 out of 662 microbiology students had nasal carriage of S.aureus. This number of participants was equivalent to 27.79 percent of the total number of the participants. The quoted conventionally values of nasal carriage for S.aureus ranged from 20 percent to 40 percent (Kitti, Boonyonying & Sitthisak, 2011).

Papers regarding outpatient interaction from the Cosmopolitan population at Dehli showed a colonization rate of 5.3 percent, Japan had a rate of 32.4% while USA reported a percentage of 32.4 among the adults with S.aureus. This was higher than the results of this survey.  The survey found that S.aureus prevalence in healthy students was 27.79 percent which is lower than the findings of Delhi which had a percentage of 37.3. Other surveys among workers in health care centers especially the ones in burns and Intensive Care Units have a conclusion that the rate of carrier of S.aureus is ranges from 6-50 percent. The spread of the bacterial is associated with the hands of health care workers (Halablab, Hijazi, Fawzi & Araj, 2010).

The bacteria species has a significant transmission medium through hand carriers which act as the reservoirs (Shibabaw, Abebe & Mihret, 2013). Prolonged use of antibiotics and hospitalizations contribute to the increased conveyance rate and transmission of S.aureus. The survey was limited since conducting surveys with specimens from the hind nares for screening detects only 75 percent of the bacteria. The prevalence of S.aureus colonization could have been underestimated by the nasal cultures since the bacteria can invade other parts of the body such as axilla and pharynx (Rackham, Ray, Franks, Bielak & Pinn, 2010).

Materials and Methods

Conclusion

The survey indicates that S.aureus nasal carriage is rated at 27.79 percent which corresponds to 184 out of 662 participants. The survey also singles out that incoming facilities pose an independent risk for S.aureus colonies. The findings of this survey are significant in control and prevention of the rapid spread of the MRSA among microbiology students which can extend to the community at large. It is recommendable to encourage hand washing among health care workers and enlighten the community about the bacteria to prevent it from spreading and minimize infections.

References

Argudín, M. A., Tenhagen, B. A., Fetsch, A., Sachsenröder, J., Käsbohrer, A., Schroeter, A., ... & Mendoza, M. C. (2011). Virulence and resistance determinants in German Staphylococcus aureus ST398 isolates from non-human origin. Applied and environmental microbiology.

Chen, B. J., Xie, X. Y., Ni, L. J., Dai, X. L., Lu, Y., Wu, X. Q., ... & Huang, S. Y. (2017). Factors associated with Staphylococcus aureus nasal carriage and molecular characteristics among the general population at a Medical College Campus in Guangzhou, South China. Annals of clinical microbiology and antimicrobials, 16(1), 28.

DeLeo, F. R., Otto, M., Kreiswirth, B. N., & Chambers, H. F. (2010). Community-associated meticillin-resistant Staphylococcus aureus. The Lancet, 375(9725), 1557-1568.

Frank, D. N., Feazel, L. M., Bessesen, M. T., Price, C. S., Janoff, E. N., & Pace, N. R. (2010). The human nasal microbiota and Staphylococcus aureus carriage. PloS one, 5(5), e10598.

Halablab, M. A., Hijazi, S. M., Fawzi, M. A., & Araj, G. F. (2010). Staphylococcus aureus nasal carriage rate and associated risk factors in individuals in the community. Epidemiology & Infection, 138(5), 702-706.

Kitti, T., Boonyonying, K., & Sitthisak, S. (2011). Prevalence of methicillin-resistant Staphylococcus aureus among university students in Thailand. Southeast Asian Journal of Tropical Medicine and Public Health, 42(6), 1498.

Lozano, C., Gómez-Sanz, E., Benito, D., Aspiroz, C., Zarazaga, M., & Torres, C. (2011). Staphylococcus aureus nasal carriage, virulence traits, antibiotic resistance mechanisms, and genetic lineages in healthy humans in Spain, with detection of CC398 and CC97 strains. International Journal of Medical Microbiology, 301(6), 500-505.

Ma, X. X., Sun, D. D., Wang, S., Wang, M. L., Li, M., Shang, H., ... & Luo, E. J. (2011). Nasal carriage of methicillin-resistant Staphylococcus aureus among preclinical medical students: epidemiologic and molecular characteristics of methicillin-resistant S. aureus clones. Diagnostic microbiology and infectious disease, 70(1), 22-30.

Olsen, K., Sangvik, M., Simonsen, G. S., Sollid, J. U. E., Sundsfjord, A., Thune, I., & Furberg, A. S. (2013). Prevalence and population structure of Staphylococcus aureus nasal carriage in healthcare workers in a general population. The Tromsø Staph and Skin Study. Epidemiology & Infection, 141(1), 143-152.

Otto, M. (2014). Staphylococcus aureus toxins. Current opinion in microbiology, 17, 32-37.

Rackham, D. M., Ray, S. M., Franks, A. S., Bielak, K. M., & Pinn, T. M. (2010). Community-associated methicillin-resistant Staphylococcus aureus nasal carriage in a college student athlete population. Clinical Journal of Sport Medicine, 20(3), 185-188.

Shibabaw, A., Abebe, T., & Mihret, A. (2013). Nasal carriage rate of methicillin resistant Staphylococcus aureus among Dessie Referral Hospital health care workers; Dessie, Northeast Ethiopia. Antimicrobial resistance and infection control, 2(1), 25.

Tong, S. Y., Davis, J. S., Eichenberger, E., Holland, T. L., & Fowler, V. G. (2015). Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management. Clinical microbiology reviews, 28(3), 603-661.