Question
Which organism, from the clinical standpoint, is NEVER resistant to penicillin?
| A. |
Haemophilus influenzae
|
| B. |
Mycoplasma pneumoniae
|
| C. |
Pseudomonas aeruginosa
|
| D. |
Streptococcus pyogenes
|
Show Answer
|
Correct Answer � D
Explanation
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|
Ans.D.
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Despite the extensive clinical use of penicillin since its introduction, Strep, pyogenes still shows no tendency to develop resistance and penicillin remains the drug of choice in infections caused by this organism.
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H. influenzae shows only moderate sensitivity to penicillin in vitro and infections prove unresponsive, although highly sensitive to ampicillin.
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Myc. pneumoniae lacks the sensitive rigid cell wall mucopeptide and is completely resistant.
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Ps. aeruginosa is resistant to benzyl penicillin but may be highly sensitive to carbenicillin, although resistant strains, often with transmissible R-factors, are increasingly found in hospital practice.
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Staph. Albus quite often is found to be resistant, either due to production of penicillinase or to some inherent mechanism.
