Microbiologic contamination of peripheral blood progenitor cells collected for hematopoietic cell transplantation

BACKGROUND: Peripheral blood progenitor cells (PBPCs) rather than bone marrow are used increasingly to provide hematologic reconstitution when transfused after marrow-ablative chemotherapy. PBPCs often are collected via central venous catheters that have remained in place for long periods of time and that may become infected. STUDY DESIGN AND METHODS: The investigators reviewed their 5-year experience in collecting PBPCs for the prevalence of bacterial contamination. Except for cotrimoxazole therapy given to prevent Pneumocystis cariini pneumonia, patients were not given antibiotic prophylaxis. RESULTS: Each patient underwent a median of 7 (range, 2–21) PBPC collections; 0.2 percent (3/1040 collections) were culture positive for bacteria (two collections contained coagulase-negative staphylococci and one contained Serratia marcescens). All culture-positive collections were discarded; no PBPCs were culture positive at the time of thawing and transfusion. CONCLUSION: This contamination rate is below that previously reported for bone marrow harvests and platelet concentrate collections. Obtaining PBPCs through large-bore central venous catheters has not added to the risk of infection in transplant patients. A program of screening in vitro cultures and strict adherence to sterility techniques can result in very low microbiologic contamination and thus obviates the need for prophylactic antimicrobials in the PBPCs and in the patient.     

Detection of cytomegalovirus antibody in platelet concentrates by fluorescence immunoassay and latex agglutination

A passive latex agglutination (PLA) test for cytomegalovirus (CMV) antibody detection has been shown to be an acceptable method of screening both donor sera and plasma from units of red cells and platelets stored in CPDA-1. However, most plateletpheresis concentrates are collected in ACD, and CMV antibody testing of ACD-stored products has not been systematically evaluated by PLA. Sera and ACD-stored platelet concentrate bag segments from 104 donors were tested by PLA and by a solid-phase fluorescence immunoassay (FIAX) as a reference standard for CMV-IgM and CMV-IgG antibodies. Sera were stored at both 4 and 22 degrees C and were tested on Days 1 and 5 of storage; segments were tested daily for 5 days. Of 63 donor samples (61%) that tested negative for CMV-IgG by FIAX, there were two false-positive results in bag segments by PLA testing, one on Day 1 and the other on Day 2 of storage. PLA testing was consistently positive in sera and segments in the 40 donors (38%) who tested positive for CMV-IgG by FIAX. Potential false-negative PLA results occurred in five bag segments derived from one donor whose serum gave equivocal CMV-IgG results on FIAX. The sensitivity and specificity of the PLA assay were 100 percent for donor sera tested at both 4 and 22 degrees C and 91.5 and 98.4 percent, respectively, for platelet bag segment tests. Although no donors positive for CMV-IgM were identified, 15 (14.4%) had equivocal IgM anti-CMV test results.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anti-hepatitis C virus (HCV) screening at a Canadian Red Cross center: significance of a positive c100 HCV enzyme-linked immunosorbent assay

The c100 hepatitis C virus (HCV) enzyme-linked immunosorbent assay (ELISA) has been used to screen blood donors to prevent transfusion-associated non-A,non-B hepatitis. This test is not specific, and only about 25 percent of c100 HCV ELISA-positive blood samples appear to transmit hepatitis C. However, the intensity of the ELISA (sample/cutoff ratio [S/C], greater than 2) could identify a subpopulation of donors that are at high risk for transmitting hepatitis. Blood samples from 20,186 volunteer blood donors at a Canadian Red Cross blood transfusion center were screened for antibodies to HCV using the c100 HCV ELISA. Fifty-nine (0.3%) of these donors were repeatably reactive on ELISA. When their samples were tested with the c100 recombinant immunoblot assay (RIBA) and second-generation RIBA (RIBA-2), 26 (44%) and 31 (52%) samples, respectively, were found to be positive. Thirty-three of the 59 ELISA-reactive donors had an S/C greater than 2. Of these 33 donors, 30 (91%) had elevated alanine aminotransferase (ALT), 27 (82%) were RIBA-2 positive, and 22 (67%) had risk factors for hepatitis. In contrast, of the 26 ELISA-reactive donors with S/C less than 2, only 7 (27%) had elevated ALT, and 4 (15%) were RIBA-2 positive and also had high risk factors for hepatitis. Thus, while the HCV ELISA may lack specificity, its intensity can serve to identify a subgroup of donors that are at high risk for transmitting hepatitis.     

Human T-lymphotropic virus (HTLV) types I and II infection in sexual contacts and family members of blood donors who are seropositive for HTLV type I or II. American Red Cross HTLV-I/II Collaborative Study Group

Interviews and laboratory testing were conducted for 168 contacts referred by former blood donors identified as seropositive for antibody to human T-lymphotropic virus type I (HTLV-I) or type II (HTLV-II). Thirty-two (28%) of 114 heterosexual contacts of seropositive donors, including 12 women and 20 men, were found to be antibody positive. None of 40 offspring (except one adult man who reported sexual contact in Puerto Rico) or 14 other (nonspousal) family members were seropositive. Thirty-one of the seropositive contacts were typeable as having either HTLV-I (52%) or HTLV-II (48%). Assessment of couples found that the median duration of the sexual relationship was significantly longer (p = 0.03) for those in which both partners were infected than in discordant pairs. Analysis of risk history data for 22 infected couples revealed that, in three cases, risk factors (Japanese ancestry or sexual contact with an injecting drug user) could be identified in the women, but not in their male partners. Among couples in which the male had the greater risk history, the risk factor was either a history of transfusion, birth or sexual exposure in an endemic area, or injected drug use. Counseling strategies for individuals with HTLV-I or HTLV-II infection should take into account the relatively high seroprevalence in their partners and should address the potential for sexual transmission in both directions.     

A systematic approach to diabetic foot infections

Foot infection is the most common reason for hospitalization and subsequent lower extremity amputation among persons with diabetes. Foot ulceration caused by diabetic neuropathy, trauma, and peripheral vascular disease can lead to a limb- or life-threatening infection. The optimum treatment of these potentially devastating conditions depends on a multidisciplinary approach that addresses the related or underlying disorders and thus ensures proper wound healing and a positive outcome. In addition to antibiotic therapy, severe soft-tissue or bone infections may necessitate surgical treatment, including drainage, débridement, and vascular reconstruction. Initial (empiric) antibiotic therapy should provide coverage against staphylococci and streptococci and should be revised according culture results. Antibiotic therapy is not indicated in clinically noninfected wounds. The duration of antibiotic treatment can range from 1 week for mild infections to 6 weeks or more for residual osteomyelitis and severe deep tissue infections. Aggressive (and sometimes repeated or staged) surgical intervention and appropriate antibiotic therapy can reduce the likelihood of a major amputation and the duration of hospitalization.     

Lower Resting State Heart Rate Variability Relates to High Pain Catastrophizing in Patients with Chronic Whiplash‐Associated Disorders and Healthy Controls

Vagally mediated heart rate variability (vmHRV) is widely respected as a psychophysiological measure of emotion regulation capacity and serves as a readily available index of executive brain areas that exert an inhibitory influence on subcortical structures. Pain catastrophizing (PC) is conceptualized as the tendency to misinterpret and exaggerate pain‐related situations that may be threatening. Chronic pain patients show lower vmHRV and higher PC. Previously, no study has investigated the association of PC and vmHRV. We examined the association of PC and vmHRV in a sample of patients with chronic whiplash‐associated disorders (WAD, n = 30) and healthy controls (n = 31). Patients with WAD showed lower vmHRV, indexed by high‐frequency HRV (effect size, Cohen's d = 0.442), and greater PC (d = 0.815). Zero‐order and partial correlations controlling for age and sex revealed that vmHRV and PC are inversely related. The results provide evidence for a psychophysiological mechanism underlying PC, in particular in chronic pain patients.