This pathogen may have been unidentified until now because of its slow growth, broad susceptibility to antimicrobial agents, and possible requirement of blood-cell lysis for recovery in culture. It should be sought as a cause of unexplained fever, especially in persons with defective cell-mediated immunity.
Two closely related species of Rochalimaea, Rochalimaea quintana and Rochalimaea henselae, are nutritionally fastidious but can be cultivated on bacteriologic media from the blood of patients with diverse clinical presentations. We report a case of culture-proven R. henselae bacteremia in a child with persistent fever. Serologic evidence of infection by R. henselae was ascertained by testing sera at two intervals for immunoglobulin G or immunoglobulin M antibodies by enzyme immunoassay and immunoblot. The case isolate and a collection of other strains (R. henselae, R. quintana, and related organisms) were used to test commercial identification systems for their comparative utility in the identification ofRochalimaea spp. on a practical basis. Of six systems designed for testing of either fastidious or anaerobic isolates of bacteria, the MicroScan Rapid Anaerobe Panel was the only system that distinguished R. henselae from R. quintana. Four of five others gave reactions that were unique within their data bases but did not distinguish Rochalimaea isolates at the species level.
Cryptosporidiosis, previously seen mostly among immunocompromised patients, is now recognized among immunocompetent patients. During a large outbreak of cryptosporidiosis in two day-care centers, we compared two procedures for the demonstration of the organism in preserved stool specimens. Of 703 stool specimens tested by both techniques, Sheather sucrose flotation (SSF) identified 127 (18.1%) as positive for Cryptosporidium sp. oocysts. Ritchie Formalin-ethyl acetate sedimentation (F/EA) plus a modified cold Kinyoun acid-fast stain (MCK) of the sediment identified 129 (18.4%) as positive for Cryptosporidium sp. oocysts. The degree of agreement between the two tests was statistically highly significant (P < 0.0001). A total of 161 (22.9%) were positive by one technique or the other; 95 (13.5%) were positive by both techniques. A total of 32 specimens were positive by SSF but negative by F/EA plus MCK, and 34 specimens were positive by F/EA plus MCK but negative by SSF. The discrepancies between the two techniques occurred in stool specimens that contained rare to a few oocysts. Other parasitic forms were found by both techniques. F/EA plus trichrome staining recovered 126 (17.9%) specimens with Giardia lamblia, whereas SSF recovered only 42 (6.0%) specimens with G. lamblia. No association (X2 = 0.02, P = 0.89) was observed between the presence of G. lamblia and Cryptosporidium sp. in these stool specimens. We concluded that F/EA plus MCK of the sediment was as effective in the concentration and identification of Cryptosporidium sp. oocysts as SSF. F/EA plus MCK may be advantageous as a single concentration method for general parasitology when Cryptosporidium sp. is also being sought.
Del.) is a commercially available blood culture system for use in pediatrics. The methodology is based on blood lysis followed by direct plating of the sample on culture media to detect bacteria and fungi. Comparative recovery rates of pathogens from blood collected in this and a conventional broth system were similar. The Isolator detected 104 of 120 clinically signfficant isolates, whereas 106 of 120 isolates were detected by the broth system. The major advantage of the Isolator methodology was early detection of septicemia. Initial detection of gram-negative bacteria occurred an average of 14.2 h earlier by the Isolator system than by the conventional broth method. The Isolator also permitted quantitation of bacteremia and fungemia. Probable contaminants were recovered from 10.0% of the cultures processed by the Isolator, but steps which could be taken to minimize this problem were identified. The Isolator is a useful method for pediatric blood cultures.
Latex agglutination and coagglutination tests are commercially available as Bactogen and the Phadebact Haemophilus Test, respectively. We evaluated both for the detection of Haemophilus influenzae type b in cerebrospinal fluids. Both tests were positive in all of 51 culture-positive cases of meningitis caused by H. influenzae. Both were more sensitive than counterimmunoelectrophoresis. Antigen was also detected by Bactogen in seven of seven additional cerebrospinal fluid specimens (compared with four of seven by Phadebact) after 1 to 15 days of antimicrobial therapy. The cerebrospinal fluid of infants with meningitis owing to other common causative agents did not react with Bactogen or Phadebact. However, the cerebrospinal fluid of one patient with overwhelming infection owing to Proteus mirabilis reacted positively with Bactogen. Cost analysis revealed that Phadebact was less expensive to perform than Bactogen. Detection of microbial antigens in cerebrospinal fluid (CSF) can offer rapid, presumptive identification of meningeal pathogens. Counterimmunoelectrophoresis (CIE) is one technique that has been successfully employed by many laboratories for the detection of Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitidis, and Streptococcus agalactiae in CSF (2, 4, 7, 9, 10, 13, 15). The reported sensitivity of CIE for meningitis varies according to the antigen and operating conditions but is approximately 60 to 80% (2, 7, 10). Alternative methods for antigen detection in CSF have been described but have been implemented less extensively so far. The optimal antigen detection method for individual laboratories may vary depending on assessments of the sensitivity, specificity, and availability of test reagents. Staphylococcal coagglutination (COA) and latex agglutination (LA) tests are generally more sensitive than CIE, according to Thirumoorthi and Dajani (13). Most investigators to
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