Use of quantitative antibiogram analysis to determine the clonality of coagulase-negative Staphylococcus species from blood culture.

Two phenotypic methods, quantitative antibiogram analysis and colony morphology, were compared to pulsed-field gel electrophoresis (PFGE) for distinguishing the clonality of coagulase-negative Staphylococcus (CNS) species. The results of these three methods were correlated with the patients' clinical findings for 23 episodes in which CNS species were isolated from two blood culture bottles within a 24-h period. Quantitative antibiogram and colony morphology at 24 h correlated with PFGE typing in 21 (91%) and 20 (87%) episodes, respectively. All episodes associated with CNS strains with identical PFGE patterns had quantitative antibiogram similarity coefficients < 10, whereas most episodes associated with strains with different PFGE patterns had quantitative antibiogram similarity coefficients >or= 17. The CNS isolate pairs were less likely to be associated with infection if the strains had different PFGE types or a quantitative antibiogram similarity coefficient >or= 17. Clinical microbiology laboratories should consider use of the quantitative antibiogram similarity coefficient to aid clinicians in distinguishing infection-associated CNS blood isolates from contaminants.

Critical evaluation of 4-week incubation for fungal cultures: is the fourth week useful?

To determine the benefit of a 4-week incubation for mycology cultures, we evaluated all positive cultures during the fourth week of incubation in a 1-year period. Of 3,855 positive mycology cultures (yeast, 82%; molds, 18%), 62 (1.6%) were positive during the fourth week (yeast, 42%; molds, 58%). Only 15 of the 62 cultures (24%) were considered clinically relevant (2 isolates from invasive fungal infection and 13 isolates from cutaneous mycosis). With the exception of those from skin samples, isolates recovered during the fourth week are rarely important for patient care.

Something's rotten: a nosocomial outbreak of malodorous Pseudomonas aeruginosa.

From July 1994 through November 1996, a phenotypically unique strain of Pseudomonas aeruginosa producing a pungent, "rotten-potato" odor and a positive lysine decarboxylase reaction was isolated from 39 patients at UCLA Medical Center (Los Angeles). Most cases (95%) were in intensive care units and had clinical infections (72%). Most isolates (74%) were recovered from cultures of respiratory secretions. To determine risk factors for acquisition of the organism, 23 cases were compared with 23 randomly selected controls matched by service and isolate date. Multivariate analysis revealed that isolation of malodorous P. aeruginosa was associated with mechanical ventilation of > 24 hours' duration (odds ratio [OR] = 9.4; P = .001) and transfer from an outside hospital (OR = 5.7; P = .04). DNA from outbreak strains hybridized to P. aeruginosa-specific toxin A and phospholipase C gene probes and all outbreak isolates tested were found to be identical by use of pulsed-field gel electrophoresis. An unusual phenotypic characteristic of the strain led to the recognition of a nosocomial outbreak of P. aeruginosa infection associated with mechanical ventilation.

Antiphospholipid syndrome associated with cytomegalovirus infection: case report and review.

Antiphospholipid antibodies are commonly related to connective tissue disorders, the use of certain drugs, and infection. It is thought that antiphospholipid syndrome (APS) is associated primarily with connective tissue disorders. We describe a healthy young male who had an episode of APS that was associated with cytomegalovirus infection and who developed mesenteric and femoropopliteal thrombosis. He responded well to treatment with anticoagulants; 6 months after the onset of APS, IgM and IgG anticardiolipin antibody titers declined. We point out the importance of screening for infectious agents in cases of APS; if the agents are identified, APS may be transitory.

Outbreak of Stenotrophomonas maltophilia bacteremia in allogenic bone marrow transplant patients: role of severe neutropenia and mucositis.

From March 1997 through November 1997, 8 allogenic bone marrow transplant (BMT) patients developed Stenotrophomonas maltophilia bacteremia on the hematology service at UCLA Medical Center (Los Angeles). Five of these patients had undergone transplantation during the same hospitalization that S. maltophilia bacteremia was detected (case patients). Compared with 7 concurrently hospitalized allogenic BMT patients (control patients), the 5 case patients were more likely to have been hospitalized in room A (P=.045), to have severe neutropenia on the culture date (P=.028), to have a longer duration of severe neutropenia (P=.05), to have severe mucositis (P=. 028), and to have received total parenteral nutrition (P=.028). Pulsed-field gel electrophoresis revealed that 2 of 3 isolates from case patients hospitalized in room A were identical. In allogenic BMT patients, severe neutropenia and severe mucositis may promote infection with S. maltophilia by impairing host defenses.

A multistate nosocomial outbreak of Ralstonia pickettii colonization associated with an intrinsically contaminated respiratory care solution.

From 1 February through 30 April 1998, 4 hospitals reported a total of 34 patients colonized with Ralstonia pickettii. All but 1 had been exposed to 0.9% saline solution manufactured by 1 company (Modudose; Kendall, Mainsfield, MA), which was used during endotracheal suctioning. Culture of saline solution from previously unopened vials yielded R. pickettii. All available product and patient isolates were genotypically related by pulsed-field gel electrophoresis (PFGE) analysis. The contaminated saline solution was manufactured at the same plant that had been associated with a similar outbreak in 1983. The 1983 and 1998 R. pickettii isolates were unrelated, as determined by PFGE. In both 1983 and 1998, a 0. 2-microm cartridge filter was used for terminal sterilization. The detection of R. pickettii should alert hospital personnel to the possibility of product contamination. In this outbreak, prompt notification of public health agencies resulted in rapid notification of other health care providers, which likely prevented additional outbreaks.