Relative effectiveness of penicillin, neomycin and erythromycin on the inhibition of growth of Streptococcus pneumoniae
Introduction:
An approximate 1.1 million annual deaths worldwide are attributed to the to bacteria known as Streptococcus pneumoniae. Today, S. pneumoniae is among the most significant causes of bacterial disease in humans and remains to be one of the top 10 causes of death in the U.S (Hoskins, 2001). This pathogenic bacteria causes a variety of clinical issues and is the leading cause of meningitis and bacterial pneumonia in the United States (Hoskins, 2001). This bacteria has also been found to be a major cause of ear/sinus infections, bloodstream infections and even sepsis. (Hoskins, 2001). Researchers …show more content…
The two antibiotics that prevented the growth of the bacteria were erythromycin and penicillin. The antibiotic that had no effect on the S. pneumoniae was neomycin. The zone of inhibition (displayed in figures 1 and 2) produced by the saturated penicillin disk was 29.2 mm. Erythromycin had a zone of inhibition of 17.8 mm. Conclusively, penicillin was the most effective in inhibiting the growth of the sample of S. pneumoniae bacteria. The findings correlated with this study 's initial hypothesis in that erythromycin and penicillin would have the greatest effect on S. pneumoniae and confirmed that neomycin has no effect on the cultured bacteria. The results of this depend largely on what strain of S. pneumoniae was used. There are more than 90 strains of S. pneumoniae and many of them, through either mutation or natural selection have developed resistance to certain antibiotics. Due to the both successful growth of S. pneumoniae on the red agar plate and the visible zones of inhibition around two of the saturated antibiotic disks, there proved to be no conflicts and anomalies, nor any other factors (besides the cultivated bacteria and antibiotics disks) that contributed to the zones of