By Dr. F. Edward Yazbak
Performance and Problems
The abuse of penicillin and other antibiotics has led to the proliferation of resistant strains of Streptococcus pneumoniae (pneumococcus). The wide use of Prevnar, a pediatric pneumococcal 7-valent conjugate vaccine, since 2000 is now resulting in problems that could have been anticipated and should now be disclosed.
Streptococcus pneumoniae was first isolated by Louis Pasteur in 1881. Its association with lobar pneumonia was first recorded by Friedlander and Talamon in 1883. In 1926, the organism was named Diplococcus pneumonia because of its characteristic appearance as two adjacent cocci or round bacteria. In 1974, it was renamed Streptococcus pneumoniae. Because the organism caused bacterial pneumonia, many pediatricians simply called it pneumococcus so as not to confuse parents who may think that it is somehow involved in steprococcal disease, such as “strep throat,” which is caused by group A beta-hemolytic Streptococcus. Although both organisms are gram-positive – appearing dark blue to purple on a gram-stained bacteriological smear – they are easily distinguishable.
In the 1960s, the pneumococcus was exquisitely sensitive to penicillin – so much so that antibiotics-sensitivity testing was not routinely performed on pure cultures of the organism in most microbiology laboratories.
Pneumococcal infections can be invasive (pneumonia, meningitis and bacteremia) or non-invasive (otitis media, sinusitis). Underlying conditions associated with increased risk and mortality are HIV infection, sickle-cell anemia, asplenia (congenital or surgical), chronic organ failures and, in general, any debilitating disease.
Children with invasive pneumococcal disease were usually toxic and febrile. They also had strikingly elevated total white blood counts (WBC) with a shift to the left, a relative increase in polymorphonuclear leucocytes. Those who had pneumonia were tachypneic (breathing fast) and had clinically abnormal and localizing findings by auscultation with a stethoscope and by percussion. The art of percussion, banging with one’s index finger on the patient’s chest to detect dull areas of pneumonia is used less and less today. In fact, the art of diagnosis seems to be disappearing. We now have x-rays, CT scans, laboratory and computer-assisted diagnoses. Clinical acumen seems to be passÃ©.
Almost always, the diagnosis of invasive disease was easy and the treatment with penicillin promptly effective.