Investigation of Escherichia coli Harboring the mcr-1 Resistance Gene - Connecticut, 2016.

The mcr-1 gene confers resistance to the polymyxins, including the antibiotic colistin, a medication of last resort for multidrug-resistant infections. The mcr-1 gene was first reported in 2015 in food, animal, and patient isolates from China (1) and is notable for being the first plasmid-mediated colistin resistance mechanism to be identified. Plasmids can be transferred between bacteria, potentially spreading the resistance gene to other bacterial species. Since its discovery, the mcr-1 gene has been reported from Africa, Asia, Europe, South America, and North America (2,3), including the United States, where it has been identified in Escherichia coli isolated from three patients and from two intestinal samples from pigs (2,4-6). In July 2016, the Pathogen Detection System at the National Center for Biotechnology Information (Bethesda, Maryland) identified mcr-1 in the whole genome sequence of an E. coli isolate from a Connecticut patient (7); this is the fourth isolate from a U.S. patient to contain the mcr-1 gene.

The difference between fingerstick and venous hemoglobin and hematocrit varies by sex and iron stores.

BACKGROUND: Fingerstick blood samples are used to estimate donor venous hemoglobin (Hb). STUDY DESIGN AND METHODS: Fingerstick Hb or hematocrit (Hct) was determined routinely for 2425 selected donors at six blood centers, along with venous Hb. Using sex and measures of iron status including absent iron stores (AIS; ferritin < 12 ng/mL), linear regression models were developed to predict venous Hb from fingerstick. RESULTS: Across all subjects, fingerstick Hb was higher than venous Hb in the higher part of the clinical range, but lower in the lower part of the range. The relationship varied by sex and iron status. Across centers, a female donor had on average a venous Hb result 0.5 to 0.8 g/dL lower than a male donor with the same fingerstick Hb and iron status. Similarly, a donor with AIS had on average a venous Hb result 0.3 to 1.1 g/dL lower than an iron-replete donor with the same fingerstick value and sex. An iron-replete male donor with a fingerstick result at the cutoff (Hb 12.5 g/dL) had an acceptable expected venous Hb (12.8 to 13.8 g/dL). A female donor with AIS with a fingerstick result at the cutoff had an expected venous Hb below 12.5 g/dL (11.7 to 12.4 g/dL). Of females with AIS, 40.2% donated blood when their venous Hb was less than 12.5 g/dL. CONCLUSIONS: Fingerstick is considered a useful estimator of venous Hb. However, in some donor groups, particularly female donors with AIS, fingerstick overestimates venous Hb at the donation cutoff. This significant limitation should be considered in setting donor fingerstick Hb or Hct requirements.

Direct assessment of cytomegalovirus transfusion-transmitted risks after universal leukoreduction.

BACKGROUND: Cytomegalovirus (CMV) transfusion-transmitted disease (TTD) remains a clinical concern. Universal leukoreduction has become one of the main strategies for the prevention of CMV-TTD. Through prospective clinical follow-up and testing of transfusion recipients (TRs), the risk for CMV-TTD was studied. STUDY DESIGN AND METHODS: Transfused units were all leukoreduced and not prospectively screened for CMV. For TRs with negative baseline CMV testing results (CMV total antibody and DNA), all follow-up TR samples were tested for CMV total antibody and DNA, and retained linked donor serum samples were tested for CMV total antibody. In cases when CMV-TTD was suspected, donor sera were also tested for CMV DNA and selected TR samples were tested for CMV immunoglobulin M antibody. Evaluable transfusion was defined as a transfusion with TR sample(s) collected 14 to 180 days posttransfusion. RESULTS: Forty-six TRs were negative for CMV at baseline. There were 1316 evaluable cellular blood transfusions to these TRs. Of 1316 evaluable cellular products, 460 (35%) were positive for CMV total antibody tested using linked donor samples. Three cases of probable CMV-TTD were found; however, there was no definitive proof from donor follow-up that they were transfusion associated. CONCLUSION: Among all 46 baseline seronegative recipients and 1316 evaluable transfusions, the calculated overall CMV-TTD risk was up to 6.5% (95% confidence interval [CI], 1.0%-18.0%) in terms of TRs and up to 0.23% (95% CI, 0.06%-0.62%) in terms of non-CMV-screened leukoreduced cellular products. In summary, after universal leukoreduction, CMV-TTD, while uncommon, may still occur.

A prospective study of multiple donor exposure blood recipients: surveillance value and limitations for hemovigilance.

BACKGROUND: There have been few recent systematic studies of blood recipients for direct evidence of blood safety, especially for emerging pathogens that may pose a threat to the blood supply. STUDY DESIGN AND METHODS: Recipients who would likely require transfusion from multiple donors were recruited and a blood specimen was collected before their first study transfusion and at intervals after their study transfusion(s). Blood samples associated with the units that were transfused to enrolled recipients were also collected. Part of each recipient specimen and selected donor specimens was tested for the targeted blood-borne agents, parvovirus B19 (B19) and Chlamydia pneumoniae (Cp), that were piloted in this study, and the remaining material was kept in a repository. RESULTS: Between April 2004 and December 2006, a total of 120 recipients were recruited with 4047 subsequent donor exposures. On average, each recipient was followed up seven times. Of recipients who were adequately followed up and were initially immunoglobulin G antibody negative, one in 31 and one to two in 49 seroconverted to B19 and Cp after a total of 922 and 1413 evaluable transfusions, respectively. The detection of seroconversion was complicated by passively acquired donor antibodies for these two seroprevalent agents. Negative results for nucleic acids of the agents limited our ability to further clarify the relationship of these seroconversions to transfusion-transmitted infection. CONCLUSION: The risk of transfusion-associated B19 infection appears to be low but no conclusion of transfusion transmission can be made for Cp. The approach piloted through this study offers added value beyond the current hemovigilance strategy in the United States.