Nocardia bacteremia. Report of 4 cases and review of the literature.

Bacteremic nocardiosis is reported rarely. We discuss 4 recent cases seen at our institution and 32 other cases described in the English literature. We found that patients with bacteremic nocardiosis were similar in presentation, risk factors, course, and therapeutic outcome to nonbacteremic patients with nocardiosis. The presence of endovascular foreign bodies appeared to be the only unique risk factor associated with bacteremic illness. Seeding of the central nervous system appeared to be relatively uncommon. Thirty percent of patients with nocardemia had concomitant bacteremia with other pathogens, mostly Gram-negative organisms. Nocardia grew in a variety of growth media, and the median incubation time to detection was 4 days. Fifty percent of patients with Nocardia bacteremia died. Positive blood cultures were a preterminal finding in the fatal, acute cases and occurred relatively early in the subacute, nonfatal cases. Poor outcome seemed to correlate with acute onset of nocardiosis (duration less than 1 month), late identification of nocardemia, involvement of more than 2 sites, and the lack of treatment with a sulfonamide-containing regimen.

Quantitative cultures of the mucosal-associated bacteria in the mechanically prepared colon and rectum.

Little is known about the mucosal microflora of the colon and rectum at the time of elective surgery. Our objective was to determine the concentrations of anaerobic and aerobic bacteria associated with the mucosa of the mechanically prepared large bowel. Ten patients were studied after a standard polyethylene glycol-electrolyte lavage preparation. No patient had taken antibiotics in the preceding four weeks. Sterile wire brushes passed through the colonoscope during advancement were used to culture the rectal, transverse colon, and cecal mucosa. Total anaerobic, aerobic, Gram-positive, and enteric bacterial counts were determined along with specific cultures for Bacteroides fragilis, Clostridium difficile, Escherichia coli, Pseudomonas aeruginosa, enterococcus, and staphylococcus species. The results showed that there was a significant increase (P < 0.01) in aerobes, anaerobes, enterics, Gram positives, B. fragilis, and E. coli mucosal counts with proximal progression. Aerobes showed a steady gradient, while anaerobes demonstrated an increase from the rectum to the transverse colon but no change between the transverse colon and cecum. We conclude that, in the prepared bowel, there is an increase in the mucosal bacterial counts in the more proximal portions of the bowel. The results may serve as a baseline for future studies on the mucosal-associated bacteria of the large intestine.

Nutritionally variant streptococci.

Streptococci requiring either pyridoxal or L-cysteine for growth were first observed 30 years ago as organisms forming satellite colonies adjacent to colonies of "helper" bacteria. Although they were previously considered nutritional mutants of viridans streptococcal species, the nutritionally variant streptococci (NVS) are currently thought to belong to distinct species of the genus Streptococcus. NVS strains may display pleomorphic cellular morphologies, depending on their growth conditions, and are distinguished from most other streptococci by enzymatic and serological characteristics and the presence of a cell wall chromophore. NVS are found as normal inhabitants of the oral cavity, and in addition to their participation in endocarditis, they have been isolated from a wide range of clinical specimens. Endocarditis caused by NVS is often difficult to eradicate; combinations of penicillin and an aminoglycoside are recommended for treatment. The unique physiological features of the NVS contribute to the difficulties encountered in their recovery from clinical specimens and may play a role in the problems associated with successful treatment of NVS endocarditis.

In vitro activities of daptomycin and other antimicrobial agents against vancomycin-resistant gram-positive bacteria.

A comparative evaluation of daptomycin and eight other antimicrobial agents was performed by the agar dilution technique with 56 strains of vancomycin-resistant gram-positive bacteria, including Leuconostoc, Lactobacillus, and Pediococcus spp. Erythromycin, deptomycin, clindamycin, and gentamicin exhibited the greatest activities, whereas penicillin, ampicillin, and cefotaxime showed moderate activities. The organisms were all highly resistant to vancomycin and cefoxitin.

Bacteremia with Streptococcus bovis and Streptococcus salivarius: clinical correlates of more accurate identification of isolates.

Two biotypes of Streptococcus bovis can be identified by laboratory testing and can be distinguished from the phenotypically similar organism Streptococcus salivarius. We assessed the clinical relevance of careful identification of these organisms in 68 patients with streptococcal bacteremia caused by these similar species. S. bovis was more likely to be clinically significant when isolated from blood (89%) than was S. salivarius (23%). There was a striking association between S. bovis I bacteremia and underlying endocarditis (94%) compared with that of S. bovis II bacteremia (18%). Bacteremia with S. bovis I was also highly correlated with an underlying colonic neoplasm (71% of patients overall, 100% of those with thorough colonic examinations) compared with bacteremia due to S. bovis II or S. salivarius (17% overall, 25% of patients with thorough colonic examinations). We conclude that careful identification of streptococcal bacteremic isolates as S. bovis biotype I provides clinically important information and should be more widely applied.

Routine culture of stool specimens for Yersinia enterocolitica is not a cost-effective procedure.

Cefsulodin-Irgasin-novobiocin (CIN) agar was used to isolate Yersinia enterocolitica from 3,622 stool specimens received in our laboratory during a 1-year period. Seven specimens (0.2%) yielded Y. enterocolitica strains from a total of five patients. The low frequency of Y. enterocolitica isolation observed, coupled with the isolation of this pathogen from three of the five patients by our standard stool examination protocol, leads us to conclude that routine culture of stool specimens on CIN agar is not a cost-effective procedure.