Essay On Penicillin Neomycin And Erythromycin

1659 Words 7 Pages
Sydney Meyers
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
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In 1997 the Disease Control and Prevention (CDC) conducted a seven region examination in the United states and concluded that even with how successful penicillin is in combating the S. pneumoniae bacteria, 25% of isolates of the pathogenic bacteria were resistant to penicillin (Fuchs, 2000). The same year SENTRY () did a surveillance study and found that the overall rate of resistance to another commonly used antibiotic erythromycin, was approximately 12% (Fuchs, 2000). Neomycin, in most instances and studies has no effect on inhibiting the growth and spread of the S. pneumoniae bacteria (Fuchs, 2000). Based on previous research and studies, penicillin and erythromycin, excluding neomycin, will inhibit the growth of S. pneumoniae depending on what strain of bacteria is present. If penicillin and erythromycin indeed inhibit the growth if the bacteria, there will be a zone of inhibition around the saturated antibiotic …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

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