Clinical relevance of viridans and nonhemolytic streptococci isolated from blood and cerebrospinal fluid in a pediatric population.

Laboratory records were reviewed to assess the clinical relevance of isolating viridans (VS) and nonhemolytic (NHS) streptococci from blood and cerebrospinal fluid (CSF) specimens in a pediatric setting. During a nine-month period, 722 of 6,569 blood cultures and 113 of 2,023 CSF cultures were positive for one or more organisms. There were 26 VS and 10 NHS blood isolates from 30 patients and five NHS isolates from the CSF of five additional patients. The patients ranged in age from five weeks to 16 years. The charts of 34 patients were reviewed for evidence of sepsis or meningitis and the physician's response to the positive cultures. Three patients had subacute bacterial endocarditis (SBE) with multiple positive blood cultures. All other patients, including six oncology patients, failed to show a positive correlation between the isolation of VS or NHS and the disease process. Speciation and MIC testing were performed on 13 isolates, including those from all SBE and four oncology patients. Because of the lack of significance of VS and NHS from blood and CSF specimens in patients other than those with SBE, the authors conclude that extensive microbiologic workup of VS and NHS is not necessary without appropriate clinical indications such as SBE or immunosuppression.

Occurrence of mucoid M-18 Streptococcus pyogenes in a central Ohio pediatric population.

During a 1-year period from October 1986 through September 1987, we recovered 116 mucoid, hemolytic Streptococcus pyogenes isolates from clinical specimens collected from patients seen at our pediatric institution. A total of 102 isolates were from throat cultures (101 for pharyngitis, 1 for acute rheumatic fever), 13 were from other superficial body sites, and 1 was from pleural fluid. All of 40 mucoid isolates tested to date were determined to be M-type 18 strains. A direct latex agglutination test for group A carbohydrate antigen in throat swab specimens was equally sensitive in detecting M-18 mucoid and nonmucoid strains (45 of 77 [58%] and 795 of 1,186 [67%], respectively; not significant, P greater than 0.05). Antimicrobial susceptibility tests performed with 40 mucoid and 40 nonmucoid isolates against penicillin and nine other antimicrobial agents showed all strains to be susceptible, with no difference in MICs. All isolates tested were also considered fully susceptible to the bactericidal activity of penicillin. Further studies are needed to establish the relative virulence of M-18 strains and their possible association with the resurgence of acute rheumatic fever in central Ohio and other areas of the United States.

Evaluation of a direct identification method for Staphylococcus aureus from blood culture broth.

We evaluated the reliability of Staphaurex (Wellcome Diagnostics, Dartford, England) for the direct identification of staphylococci from blood culture broth with evidence of positivity and a suggestive Gram-stained smear. Our evaluation indicates that this application is of limited sensitivity, thus reducing the value of a negative test. However, since the test is highly specific, a positive test is significant in predicting the isolation of Staphylococcus aureus.

Selective and differential medium for recovery of Pseudomonas cepacia from the respiratory tracts of patients with cystic fibrosis.

A selective and differential medium, OFPBL (oxidation-fermentation base supplemented with agar, lactose, and two antimicrobial agents), for the isolation of Pseudomonas cepacia from respiratory specimens of patients with cystic fibrosis was developed and tested. Among 725 specimens submitted from seven centers over a 4- to 6-month period, 58 (8%) yielded P. cepacia on OFPBL; only 19 of these were recovered on MacConkey or sheep blood agar (P less than 0.001). No isolate was recovered on MacConkey or sheep blood agar alone. Ranges of recovery rates among centers were 0 to 15% on OFPBL and 0 to 10% on MacConkey or sheep blood agar. Ninety percent of P. cepacia isolates were detected on OFPBL in less than or equal to 3 days. Other nonfermenters and yeasts isolated on OFPBL were distinguished from P. cepacia by failure to acidify the medium. The new medium was clearly superior to MacConkey and sheep blood agars for the isolation of P. cepacia from the respiratory secretions of patients with cystic fibrosis.

Comparison of throat and nasopharyngeal swab specimens for culture diagnosis of Bordetella pertussis infection.

During a 9-month period, we evaluated the relative sensitivity of throat and nasopharyngeal swab cultures for isolation of Bordetella pertussis. Of 38 pertussis cases, 36 (95%) had positive nasopharyngeal cultures, while only 16 of 36 (44%) had positive throat cultures. There were no cases of nasopharyngeal-negative, throat-positive cultures. The sensitivity of the direct fluorescent-antibody test was 70% when compared with culture.

Cefuroxime therapy for bacteremic soft-tissue infections in children.

Although it is used extensively in Europe, there is a limited amount of published data concerning pediatric clinical experience with cefuroxime in the United States. Thirty-six children, ranging from 3.5 to 57 months of age, received intravenous cefuroxime (75 mg/kg/day in three divided doses) for soft-tissue infections of the face or epiglottis. Infections treated included preseptal (19 patients) and buccal (13 patients) cellulitis and epiglottitis (four patients). Blood cultures were positive in 22 patients, yielding Haemophilus influenzae type b in 17 (four were beta-lactamase-positive), Streptococcus pneumoniae in four; and beta-lactamase-positive, nontypable H influenzae in one. An additional five patients with buccal cellulitis had negative blood cultures but H influenzae type b antigenuria. A satisfactory clinical response was noted in all patients, and repeated blood cultures performed in initially bacteremic patients were sterile. Cefuroxime therapy was well tolerated, and abnormal laboratory results were infrequent, except for absolute granulocytopenia (granulocytes, less than 1,500/cu mm), which occurred in six patients but could not be ascribed to a drug effect because of the uncontrolled design of our study. Treatment with cefuroxime appears to be a safe and effective therapy for pediatric soft-tissue infections due to H influenzae and S pneumoniae.