Streptococcus pneumoniae: impact of antibiotic resistance in pediatrics

Active immunization in the United States: developments over the past decade

The Centers for Disease Control and Prevention has identified immunization as the most important public health advance of the 20th century. The purpose of this article is to review the changes that have taken place in active immunization in the United States over the past decade. Since 1990, new vaccines have become available to prevent five infectious diseases: varicella, rotavirus, hepatitis A, Lyme disease, and Japanese encephalitis virus infection. Improved vaccines have been developed to prevent Haemophilus influenzae type b, pneumococcus, pertussis, rabies, and typhoid infections. Immunization strategies for the prevention of hepatitis B, measles, meningococcal infections, and poliomyelitis have changed as a result of the changing epidemiology of these diseases. Combination vaccines are being developed to facilitate the delivery of multiple antigens, and improved vaccines are under development for cholera, influenza, and meningococcal disease. Major advances in molecular biology have enabled scientists to devise new approaches to the development of vaccines against diseases ranging from respiratory viral to enteric bacterial infections that continue to plague the world's population.

Acute otitis media: bacteriology and bacterial resistance in 205 pediatric patients

Acute otitis media (AOM) is one of the most frequent diagnoses in children below the age of 2 years. Treatment is usually based on information included in the literature concerning bacteriology. The purpose of this work was to define the most frequent germs in the etiology of AOM within our community, in order to optimize therapeutics for this pathology. Cultures in middle ear secretions obtained through tympanocentesis were performed to this end, ensuring careful sample taking and processing. The results obtained are similar to those published in previous papers for which Streptococcus pneumoniae and Haemophilus influenzae proved to be the predominant germs. However, there are certain discrepancies concerning the incidence of Moraxella catarrhalis and this has a direct impact on the total percent of resistant strains, thus modifying therapeutic approaches for treatment of AOM. The antibiotic sensitivity profiles of the most frequent etiologic agents were studied in accordance with the principles established by the 'National Committee for Clinical Laboratory Standards' (NCCLS).

Pneumococcal conjugate vaccines - implications for community antibiotic prescribing

Infections caused by Streptococcus pneumoniae are a major cause of morbidity and mortality in the pediatric population worldwide. Development of increasing resistance to multiple classes of antibiotics is making treatment of infections caused by this organism much more difficult. In order to prevent disease, a 23-valent pneumococal polysaccharide vaccine is available. However, this vaccine is poorly immunogenic in infants and young children. The development and licensing of pneumococcal conjugate vaccines that are safe and effective in the pediatric population is an important step in our ability to decrease the prevalence of pneumococcal disease seen.

Pneumococcal antibiotic resistance and rates of meningitis in children

OBJECTIVES/HYPOTHESIS

Recent studies have shown alarmingly high rates of antibiotic resistance in Streptococcus pneumoniae isolates from patients with otitis media. A recent study has implicated resistant S pneumoniae for rising rates of acute mastoiditis. The purpose of this study was to determine whether S pneumoniae antibiotic resistance has similarly affected the rate of pediatric community-acquired meningitis, the most common intracranial complication of otitis media.

STUDY DESIGN

Retrospective chart review.

METHODS

All cases of pediatric community-acquired meningitis treated at an academic tertiary care hospital during a 10-year period were reviewed, and meningitis rates were calculated as a proportion of yearly admissions.

RESULTS

The overall rate of meningitis decreased linearly during the study period (P = .001). This was largely because of a drop in the rate of Haemophilus influenzae meningitis (P = .001), corresponding with the introduction of H influenzae type B vaccine. Annual rates of S pneumoniae meningitis did not change. Only one case of S pneumoniae meningitis was due to a highly penicillin-resistant strain and isolates from four cases had intermediate sensitivity. Twenty-four of 83 cases were associated with antecedent acute otitis media and 63% of these had been treated with antibiotics before admission. Otitis media, as a cause of meningitis, did not increase during the study period.

CONCLUSION

S pneumoniae is responsible for a greater proportion of cases of pediatric community-acquired meningitis. However, this is because of a decline in the rate of H influenzae cases, not the rise in S pneumoniae antibiotic resistance.

Differentiation of typhoid fever from fulminant hepatic failure in patients presenting with jaundice and encephalopathy

OBJECTIVE

To determine the clinical and laboratory features that allow the early diagnosis of typhoid fever in patients who present with jaundice and encephalopathy.

PATIENTS AND METHODS

This 12-month prospective study, conducted in Bangalore, India, between 1990 and 1991, evaluated the clinical and laboratory features of all patients (N=47) who presented with encephalopathy within 8 weeks of onset of jaundice. Ciprofloxacin and dexamethasone were used to treat 11 patients diagnosed on blood culture as having typhoid fever. The other 36 patients were presumed to have fulminant hepatic failure with a viral cause and were treated with supportive measures (bioartificial liver support and transplantation were not available).

RESULTS

In patients with jaundice and encephalopathy, a liver span of greater than 9 cm on physical examination, thrombocytopenia, elevated alkaline phosphatase level, aspartate aminotransferase level greater than alanine aminotransferase level, and only mild prolongation of the prothrombin time suggested a diagnosis of typhoid fever. All 11 patients diagnosed as having typhoid fever had an excellent response to treatment with ciprofloxacin and dexamethasone with no mortality and with normalization of the liver test results in 2 weeks. On the other hand, 30 of the 36 patients with nontyphoid fulminant hepatic failure died.

CONCLUSIONS

In patients presenting with jaundice and encephalopathy, physical examination and simple laboratory tests can help make an early diagnosis of typhoid fever. We believe that patients with a presumptive diagnosis of typhoid fever should be treated with ciprofloxacin and dexamethasone, even before the results of blood cultures are available.

Bacterial resistance and antibiotic use in the emergency department

Antibiotic resistance among bacteria that are commonly encountered in the pediatric emergency department is a fact of nature. New antibiotics will provide some help, but probably only temporarily. Vaccine strategies seem to provide the best answer to resistance, and many physicians eagerly await the conjugated pneumococcal vaccines, which we can only hope to be as successful as the H. influenzae type b vaccines. Vaccines against other resistant organisms are likely further off. At this point, a major goal must be to limit the prevalence of antibiotic resistance. In considering this goal, two complementary strategies are key. The first is to avoid antibiotics in situations in which they are unlikely to provide benefit, such as for colds, URIs, and bronchitis. The second is to use narrow-spectrum antibiotics as much as possible to minimize selective pressure. Emerging evidence shows that these strategies can be effective. In a day-care center in Omaha, Nebraska, Boken et al showed that nasopharyngeal carriage of highly resistant S. pneumoniae decreased dramatically among attendees when antibiotic use decreased. In Iceland, a nationwide campaign that resulted in decreased antibiotic use was followed by a decrease in the incidence of penicillin-resistant pneumococcal infections from 20.0% to 16.9% and a decrease in the rate of carriage of resistant pneumococci among day-care-center attendees from 49% to 15%. In Finland, erythromycin resistance in Group A streptococci recovered from pharyngeal and pus samples had reached 13% in 1990. National guidelines that recommended a reduction in the use of erythromycin and other macrolide antibiotics in the treatment of outpatients with respiratory and skin infections were instituted, and by 1996, macrolide antibiotic consumption had decreased by 50%, with a similar 50% decrease in frequency of erythromycin-resistant isolates. In the absence of such national strategies, it is incumbent on physicians treating infections on a daily basis in the emergency department to consider carefully the judicious use of antibiotics.

Nosocomial transmission of penicillin-resistant Streptococcus pneumoniae

Two patients were found to harbor intermediate-level penicillin-resistant Streptococcus pneumoniae in a pediatric hospital setting. For the first patient, the bacterium was isolated from a tracheal aspirate, and for the second patient, a positive blood culture was found a short time after the index case. Two molecular typing techniques (enterobacterial repetitive intergenic consensus sequence polymerase chain reaction, and repetitive sequence-based polymerase chain reaction) demonstrated homology among these isolates, which suggests person-to-person spread. We propose the need for institution-based infection control precautions that will limit the spread of penicillin-resistant pneumococci.