RBC transfusion in the ICU. Is there a reason?

OBJECTIVE: To evaluate RBC transfusion practice in the ICU. DESIGN: Retrospective chart review. SETTING: Multidisciplinary ICU in a tertiary care center. PATIENTS: All patients admitted to the ICU with a length of stay of greater than 1 week. RESULTS: A total of 23% of all patients admitted to the ICU had a length of stay of greater than 1 week (19.6 +/- 1.6 days). Of these patients, 85% received blood transfusions (9.5 +/- 0.8 U per patient). These transfusions were not solely a function of acute blood loss. Patients were transfused a constant 2 to 3 U/wk. Patients receiving blood transfusions were phlebotomized on average 61 to 70 mL per day. Phlebotomy accounted for 49% of the variation in amount of RBCs transfused. No indication for blood transfusion was identified for 29% of transfusion events. A low hematocrit (< 25%) was the only identifiable indication in an additional 19% of events. Almost one third of all RBCs transfused were without a clear transfusion indication. CONCLUSION: The long-term ICU population receive a large number of blood transfusions. Phlebotomy contributes significantly to these transfusions. There is no clear indication for a large number of the blood transfusions given. Many blood transfusions appear to be administered because of an arbitrary "transfusion trigger" rather than a physiologic need for blood. Blood conservation and adherence to transfusion guidelines could significantly reduce RBC transfusion in the ICU.

Plasmid diversity in Escherichia coli isolated from processed poultry and poultry processors.

Plasmids of bacteria selected from different bacterial populations because they shared a distinctive antimicrobial resistance phenotype have sometimes had identical restriction fragments. Such identical plasmids are thought to belong to small and thus epidemic clones because the plasmid content of unselected resistant isolates has seemed diverse. To survey this presumed diversity and its implications for the lineage of resistance plasmids we examined the transferability, sizes and EcoR1 restriction fragment sizes of plasmids in both Escherichia coli isolated randomly from poultry raised by 16 growers as they were being processed through two plants and in isolates from the urine of women processing poultry in those plants. Forty two (24%) of 175 resistant isolates from poultry of 16 growers and 9 (26%) of 34 resistant isolates from the poultry processors transferred resistance conjugatively to varied combinations of antimicrobials. No poultry isolate had both the same expressed and the same transferred combination as any processor's isolate. The DNA bands which could be discerned in electrophoresis gels of restricted or unrestricted plasmid extracts of isolates or their transconjugants from 156 of the poultry and 24 of the poultry processors appeared diverse. Pairs of related-appearing plasmids were seen in consecutive isolates of poultry from each of two growers and in one pair from different growers. One set of identical-appearing plasmids was seen in 3 consecutive isolates from poultry of one grower, others in 2 consecutive isolates from a second grower's poultry, in 2 non-consecutive isolates of a third grower's, and in single isolates from poultry of 2 different growers. None of the plasmids from any of the human isolates appeared related to those from any other human isolate or to those of any poultry isolate. These results indicate that resistance plasmids are highly diverse and that all but two of the exceptions to complete diversity in the isolates surveyed here could be ascribed to cross colonization within flocks of individual poultry growers. Also, while none of the plasmids in the poultry isolates appeared ancestral to any of plasmids in the poultry processors' isolates, their diversity indicates that those sampled plasmids would be only a very small fraction of the total number of different plasmids in bacteria colonizing poultry processed at that time or earlier.

Absence of HIV transmission from an infected orthopedic surgeon. A 13-year look-back study.

OBJECTIVE: To determine the risk of human immunodeficiency virus (HIV) transmission from an HIV-infected orthopedic surgeon to patients undergoing invasive procedures. DESIGN: Retrospective epidemiologic follow-up study. PARTICIPANTS: A total of 2317 former patients on whom the orthopedic surgeon performed invasive procedures between January 1, 1978, and June 30, 1991 [corrected]. MAIN OUTCOME MEASURES: HIV infection or death from an acquired immunodeficiency syndrome (AIDS)-defining tumor or opportunistic infection. RESULTS: An orthopedic surgeon voluntarily withdrew from practice after testing positive for HIV. Testing for HIV was performed on 1174 former patients, representing 50.7% of patients on whom the orthopedic surgeon performed invasive procedures during the 13.5-year period. Patients were tested from each year and from each category of invasive procedure. All patients were HIV-negative by enzyme-linked immunosorbent assay. Two former patients reported known HIV infection prior to surgery. Review of AIDS case registries and vital records failed to detect cases of HIV infection among former surgical patients. The estimated cost of the initial patient notification and testing was $158,500. The patient notification and testing were conducted while maintaining the confidentiality of the orthopedic surgeon who was an active participant in the planning and execution of the study. CONCLUSIONS: The risk of HIV transmission from an HIV-infected surgeon who adheres to recommended infection control practices is extremely low. Notification and HIV testing of former patients in this setting is both disruptive and expensive and is not routinely recommended.

False resistance to imipenem with a microdilution susceptibility testing system.

Routine monitoring of antibiotic resistance at Children's Hospital, Boston, detected a dramatic increase in the prevalence of imipenem-resistant strains of Pseudomonas aeruginosa. Further studies documented that false resistance to imipenem was due, in part, to the loss of imipenem potency in customized MIC microdilution trays supplied by Sensititre Ltd. (West Sussex, United Kingdom). Recognition of the problem was delayed by use of the quality control standard recommended by the manufacturer, which were higher and broader than those suggested by the National Committee for Clinical Laboratory Standards.

Nonproduction of toxic shock syndrome toxin 1 by coagulase-negative staphylococci.

We tested 187 strains of coagulase-negative staphylococci (CNS) for the production of toxic shock syndrome toxin 1 (TSST-1). A total of 111 CNS strains were isolated from the tampons of menstruating women and 74 were isolated from unused tampons. Two strains were isolated from the genital tract of a patient with toxic shock syndrome. Strains were cultivated by the membrane-over-agar method to enhance production of TSST-1, and culture supernatants were tested by two exquisitely sensitive enzyme-linked immunosorbent assays. None of the 187 CNS strains produced TSST-1. We conclude that CNS colonizing the genital tracts of menstruating women and unused tampons produce TSST-1 infrequently, if ever, and are unlikely to play a role in toxic shock syndrome.

Does prolonged exposure to antibiotic-resistant bacteria increase the rate of antibiotic-resistant infection?

The magnitude of the risk of acquiring infections due to antibiotic-resistant bacteria, as a consequence of prolonged contact with such bacteria, is unclear. We compared antibiotic resistance patterns of Escherichia coli isolated from the urine of bacteriuric female abattoir workers with resistance patterns of E. coli cultured from 190 poultry taken from the processing line. We found E. coli in 181 (95%) of the poultry cultures; 96% of the isolates were resistant to one or more antibiotics, and 87% were multiply resistant. Of the 649 women whose urine was cultured and who had not recently received antibiotic therapy, 69 (10.6%) had positive urine cultures, with E. coli accounting for 67% of the isolates. Of the 46 E. coli isolates, 8 (17.4%) were resistant to one or more antibiotics. All of the antibiograms of the urinary isolates were unique, and only one, a strain with resistance only to streptomycin, matched those of any of the poultry isolates. Of the women tested for bacteriuria, 74 had taken antibiotics within 3 months of culture, and these women were analyzed separately. Among the recent antibiotic users, six (8.1%) had positive urine cultures, all with E. coli. Four of these isolates were resistant to at least one antibiotic; all had patterns that matched at least one of the poultry isolates. Therefore, in a population of female abattoir workers who were not receiving antibiotic therapy, despite a high exposure to resistant microorganisms of animal origin, infections were infrequently caused by organisms with resistance patterns characteristic of the livestock to which the women were heavily exposed.