Issn Print: 0891-3668

Publication Date: 1996/01/01


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The Pediatric Infectious Disease Journal® Newsletter

John D. Nelson; George H. McCracken

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Excerpt

ANAEROBIC BLOOD CULTURES In response to an item in the October 1995 Newsletter on the limited value of routine anaerobic blood cultures in pediatrics, Dr. Ellen Wald of the Children's Hospital of Pittsburgh provided information from her institution. “We collected data on the recovery of S. pneumoniae for the 12-month period from May 1994 to April 1995. S. pneumoniae was isolated from blood cultures of 74 children; in 31, the bacterial species was recovered aerobically only; in 17, it was recovered anaerobically only; and in 26, it was recovered both aerobically and anaerobically. Although it is tempting to attribute these differences to low grade bacteremias and assume they would be equally well recovered if the entire blood specimen was cultured aerobically, data from Isaacman et al. (J Pediatr, in press) suggest that some S. pneumoniae grow preferentially in an anaerobic environment.” Doctor Karen Krisher, Director of our Children's Medical Center's micro lab believes that “routine anaerobic blood cultures in pediatrics are unnecessary” unless “you are using a blood culture system that may not adequately support the growth of a streptococcus or other facultative anaerobe. The broth formulation in the adult bottle is different and does not contain the same basal medium or supplements as the pediatric formulation. In addition, the blood to broth ratio is much greater when using the adult bottles for pediatric specimens and this may influence the rate of growth and time to detection of the organism.”
AZITHROMYCIN SUSPENSION Near the end of October, the Food and Drug Administration approved the use of azithromycin (Zithromycin, Pfizer, Inc.) in infants and children. Presently its two indications in pediatrics are for treatment of acute otitis media and pharyngitis/tonsillitis, both for 5 days. The dosage for acute otitis media is 10 mg/kg as a single dose on day one followed by 5 mg/kg daily 5 days of therapy. The dosage for pharyngitis is 12 mg/kg once daily for 5 days. The cherry suspension tastes good to us and appears to be well tolerated in children.
ANOTHER NEW MACROLIDE Dirithromycin (Dynabac®, manufactured by Eli Lilly, distributed by Boch) has been recently approved for use in adults only. Other than a once daily dosage, it appears to offer no advantage over erythromycin.
ASSOCIATION OF BACTERIA AND OME Chronic middle ear effusions (otitis media with effusion or OME) for 3 months or longer are a continuing management problem. Cultures of these effusions yield bacterial pathogens in about one-third of patients; hence, the recommendation to give a trial of antibiotic therapy before considering surgery. A favorable response occurs in approximately one-quarter of the treated children. What's going on with the rest of the children with OME? Investigators at the University of Pittsburgh attempted to address this issue by testing middle ear fluid specimens from patients undergoing myringotomy for tube placement using polymerase chain reaction (PCR). They found that 29% were culture and PCR positive and an additional 48% were culture negative but PCR positive for S. pneumoniae, H. influenzae or M. catarrhalis. Were these false positives? Unlikely because the investigators were meticulous with technique and used appropriate controls. The presence of DNA from these organisms in the effusions does not necessarily mean, however, that there were live bugs there that cultures failed to recover. Because these patients had recently received one or more courses of antibiotics and because of the continuity of the middle ear space and nasopharynx, it does not surprise us that bacterial DNA is present. Perhaps DNA from other nasopharyngeal bacteria was present as well.
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