A fatal transfusion reaction associated with blood contaminated with Pseudomonas fluorescens

Bactericidal Activity of Non-Cytotoxic Cationic Nanoparticles against Clinically and Environmentally Relevant Pseudomonas spp. Isolates

Difficult-to-treat bacterial infections caused by resistant human and plant pathogens severely afflict hospitals, and concern the agri-food sectors. Bacteria from the Pseudomonadaceae family, such as P. aeruginosa, P. putida, P. fluorescens, and P. straminea, can be responsible for severe nosocomial infections in humans. P. fragi is the major cause of dairy and meat spoilage, while P. syringae can infect a wide range of economically important plant species, including tobacco, kiwi, and tomato. Therefore, a cationic water-soluble lysine dendrimer (G5-PDK) was tested on several species of Pseudomonas genus. Interestingly, G5-PDK demonstrated variable minimum inhibitory concentrations (MICs), depending on their pigment production, on Pseudomonas aeruginosa (1.6-> 6.4 µM), MICs = 3.2-6.4 µM on P. putida clinical isolates producing pyoverdine, and very low MICs (0.2-1.6 µM) on strains that produced non-pigmented colonies. Time-kill experiments established the rapid bactericidal activity of G5-PDK. In the cytotoxicity experiments on human keratinocytes, after 4 h of treatment with G5-PDK at concentrations 16-500 × MIC, more than 80% of viable cells were observed, and after 24 h, the selectivity indices were maintained above the maximum value reported as acceptable. Due to its proven bactericidal potency and low cytotoxicity, G5-PDK should be seriously considered to counteract clinically and environmentally relevant Pseudomonas isolates.

Pneumonia caused by Pseudomonas fluorescens: a case report

BACKGROUND

Pseudomonas fluorescens (P. fluorescens) has been detected in respiratory samples from patients. However, no previous reports have been published about these P. fluorescens cultures from lung tissues.

CASE PRESENTATION

Here, we report a case of pneumonia caused by P. fluorescens. P. fluorescens was identified from lung biopsy specimens for the first time in this case. According to the antibiotic susceptibility testing (AST) of P. fluorescens, the patient was given ciprofloxacin treatment. The temperature of the patient then returned to normal. Chest CT examination revealed improvements in pulmonary inflammation.

CONCLUSIONS

These findings suggest that the patients with pneumonia caused by P. fluorescens should be treated in a timely manner according to the AST results.

Microbiology, genomics, and clinical significance of the Pseudomonas fluorescens species complex, an unappreciated colonizer of humans

Pseudomonas fluorescens is not generally considered a bacterial pathogen in humans; however, multiple culture-based and culture-independent studies have identified it at low levels in the indigenous microbiota of various body sites. With recent advances in comparative genomics, many isolates originally identified as the "species" P. fluorescens are now being reclassified as novel Pseudomonas species within the P. fluorescens "species complex." Although most widely studied for its role in the soil and the rhizosphere, P. fluorescens possesses a number of functional traits that provide it with the capability to grow and thrive in mammalian hosts. While significantly less virulent than P. aeruginosa, P. fluorescens can cause bacteremia in humans, with most reported cases being attributable either to transfusion of contaminated blood products or to use of contaminated equipment associated with intravenous infusions. Although not suspected of being an etiologic agent of pulmonary disease, there are a number of reports identifying it in respiratory samples. There is also an intriguing association between P. fluorescens and human disease, in that approximately 50% of Crohn's disease patients develop serum antibodies to P. fluorescens. Altogether, these reports are beginning to highlight a far more common, intriguing, and potentially complex association between humans and P. fluorescens during health and disease.

Outbreak of Pseudomonas fluorescens bloodstream infection in a coronary care unit

An outbreak of Pseudomonas fluorescens infection in six patients in a coronary care unit was associated with a source not previously reported, namely the ice bath used for cardiac output determinations. Outbreaks of pseudobacteraemia caused by P. fluorescens and occasional blood transfusion-associated bloodstream infection (BSI) have been described. However, during the last two decades, two outbreaks of P. fluorescens BSI have been described and this article reports a third. Isolation of P. fluorescens in blood cultures must alert clinicians to the possibility of contamination of infusate, lock solutions or catheter flush.

Antibiotic and antimicrobial peptide combinations: synergistic inhibition of Pseudomonas fluorescens and antibiotic-resistant variants

Variants resistant to penicillin G (RvP), streptomycin (RvS), lincomycin (RvL) and rifampicin (RvR) were developed from a colistin-sensitive isolate of Pseudomonas fluorescens LRC-R73 (P. fluorescens). Cell fatty acid composition, K(+) efflux and sensitivity to antimicrobial peptides (nisin Z, pediocin PA-1/AcH and colistin) alone or combined with antibiotics were determined. P. fluorescens was highly sensitive to kanamycin, tetracycline and chloramphenicol at minimal inhibitory concentrations of 0.366, 0.305 and 0.732 μg/ml respectively. P. fluorescens, RvP, RvS, RvL and RvR were resistant to nisin Z and pediocin PA-1/AcH at concentrations ≥100 μg/ml but sensitive to colistin at 0.076, 0.043, 0.344, 0.344 and 0.258 μg/ml respectively. A synergistic inhibitory effect (FICI ≤0.5) was observed when resistant variants were treated with peptide/antibiotic combinations. No significant effect on K(+) efflux from the resistant variants in the presence of antibiotics or peptides alone or combined was observed. The proportion of C16:0 was significantly higher in antibiotic-resistant variants than in the parent strain, accounting for 32.3%, 46.49%, 43.3%, 40.1% and 44.1% of the total fatty acids in P. fluorescens, RvP, RvS, RvL and RvR respectively. Combination of antibiotics with antimicrobial peptides could allow reduced use of antibiotics in medical applications and could help slow the emergence of bacteria resistant to antibiotics.

Spread of Pseudomonas fluorescens due to contaminated drinking water in a bone marrow transplant unit

Pseudomonas infections are an important cause of morbidity and mortality in immunocompromised patients. We present here data for the spread of Pseudomonas fluorescens caused by a contaminated drinking water dispenser in a bone marrow transplant unit. Over a 1-month period we observed a sharp increase in the isolation of P. fluorescens from weekly pharyngeal surveillance swabs. Environmental samples were taken from a variety of water sources throughout the unit. These samples were cultured on cetrimide agar medium, and isolates were epidemiologically characterized by antibiotic susceptibility patterns and molecular typing methods. Nine patients became colonized with P. fluorescens, and six out of the nine developed febrile neutropenia. P. fluorescens was cultured after the filtration of 100 ml of drinking water from one of two stand-alone chiller units supplying cooled bottled water to the bone marrow transplant unit. All other environmental samples were negative. There were no further cases of P. fluorescens colonization after the contaminated dispenser was removed. Molecular typing showed that all P. fluorescens isolates were identical by both random amplification of polymorphic DNA PCR and pulsed-field gel electrophoresis. We recommend that such bottled water supplies not be used in high-risk areas or be subject to regular microbiological monitoring.

Multistate outbreak of Pseudomonas fluorescens bloodstream infection after exposure to contaminated heparinized saline flush prepared by a compounding pharmacy

BACKGROUND

Pharmaceutical compounding, the manipulation of ingredients to create a customized medication, is a widespread practice. In January 2005, the Centers for Disease Control and Prevention was notified of 4 cases of Pseudomonas fluorescens bacteremia that were traced to contaminated heparinized saline intravenous flush syringes prepared as a compounded medical product.

PATIENTS AND METHODS

We reviewed medical records of symptomatic patients with P. fluorescens-positive cultures of blood specimens or sections of explanted catheters, reviewed the production process of syringes, performed syringe cultures, compared isolates by pulsed-field gel electrophoresis (PFGE), and examined catheters by scanning electron microscopy.

RESULTS

We identified 80 patients in 6 states with P. fluorescens-positive cultures during December 2004-March 2006. Sixty-four patients (80%) had received a diagnosis of cancer. Seventy-four (99%) of 75 patients for whom information about catheter type was available had long-term indwelling catheters. Thirty-three (41%) of 80 cases were diagnosed 84-421 days after the patient's last potential exposure to a contaminated flush (delayed-onset cases). Compared with patients with early infection onset, more patients with delayed infection onset had venous ports (100% versus 50%; P <.001). By PFGE, clinical isolates from 50 (98%) of 51 patients were related to isolates cultured from unopened syringes. Scanning electron microscopy of explanted catheters revealed biofilms containing organisms morphologically consistent with P. fluorescens.

CONCLUSION

This outbreak underscores important challenges in ensuring the safety of compounded pharmaceuticals and demonstrates the potential for substantially delayed infections after exposures to contaminated infusates. Exposures to compounded products should be considered when investigating outbreaks. Patients exposed to contaminated infusates require careful follow-up, because infections can occur long after exposure.

Transfusion-transmitted Klebsiella pneumoniae fatalities, 1995 to 2004

Transfusion-transmitted bacterial sepsis is the third most common cause of transfusion-related fatalities reported to the Food and Drug Administration. Between October 1, 1995, and September 30, 2004, there were 665 reported transfusion fatalities. Eighty-five (13%) deaths were due to transfusion-transmitted bacterial infections, of which 58 (68%) were due to gram-negative organisms. The most common gram-negative organism associated with transfusion-transmitted deaths after receipt of platelets was Klebsiella pneumoniae. This article summarizes retrospectively the case series of deaths due to transfusion-transmitted K pneumoniae infection, reported to the Food and Drug Administration, 1995 to 2004. There were 12 deaths due to transfusion-transmitted K pneumoniae infection with 7 (58%) of the 12 cases occurring in 2002. Eleven deaths were caused by the transfusion of contaminated platelets and 1 death attributed to contaminated red blood cells. Extensive review of the seven 2002 fatality reports did not identify a common (shared) lot for items used during collection or processing of the blood product. In conclusion, in cases of suspected transfusion-transmitted septicemia, broad spectrum antibiotic coverage including coverage of gram-negative organisms should be considered. Strict adherence to infection control measures while collecting, processing, and handling all blood and blood components in both the clinical settings and in the laboratory should be followed. Further development of simple and effective test procedures for detecting bacteria in the blood is needed.

Antimicrobial susceptibility of uncommonly isolated non-enteric Gram-negative bacilli

The frequency of occurrence and antimicrobial susceptibility patterns of 3059 non-enteric Gram-negative bacilli (NGB), other than Pseudomonas aeruginosa and Acinetobacter spp., consecutively collected as part of the SENTRY Antimicrobial Surveillance Program (1997-2003) were reviewed. During this period, a total of 221,084 bacterial isolates were collected from several clinical specimens worldwide, including 25,305 (11.5%) NGB. Acinetobacter spp. and P. aeruginosa accounted for 82.7% of the NGB isolates and have been excluded from this analysis. The antimicrobial susceptibility results of 3509 strains from 13 species/genera have been analysed in this review. The isolates were tested by reference broth microdilution methods in three central laboratories using common reagents and procedures. More than 30 antimicrobial agents were tested and the results for the 18 most active compounds are reported here. Stenotrophomonas maltophilia (2076 strains; 59.2%) was the most frequently isolated pathogen in this group, followed by Aeromonas spp. (385 strain; 11.0%), Burkholderia cepacia (269 strains; 7.7%), Pseudomonas fluorescens/putida (253 strains; 7.2%) and Alcaligenes spp. (236 strains; 6.7%). All other species/genera accounted for less than 3% of the isolates analysed. The antimicrobial agents with the most consistent activity against the NGB evaluated in the present study were the newer fluoroquinolones gatifloxacin and levofloxacin with 84.1 and 84.9% susceptibility overall. Trimethoprim/sulphamethoxazole was active against 85.3% of the isolates tested, but showed reduced activity against P. fluorescens/putida (22.1% susceptibility). Antimicrobial susceptibility varied significantly between species/genera and the geographical regions evaluated. Thus, proper identification and quantitative susceptibility testing will be required for the treatment of NGB infections. Extensive worldwide surveillance programmes remain extremely important to guide empirical antimicrobial therapy for rarely isolated pathogens and also for pathogens that are not routinely tested due to the lack of standardised susceptibility testing methods.

Regulation of the cytotoxic effects of Pseudomonas fluorescens by growth temperature

We had previously shown that the psychrotrophic bacterium Pseudomonas fluorescens can act as a pathogen, inducing apoptosis and necrosis in neurons and glial cells. In the present study, we investigated the influence of the growth temperature of P. fluorescens on its infectious potential. Adherence of P. fluorescens to glial cells was found to be maximal with bacteria grown at a low temperature (8 degrees C). At that temperature the swimming behaviour was markedly reduced. An increase in the growth temperature to 19, 28 or 32 degrees C strongly diminished the binding of bacteria to host cells. Thus, the adhesion phenotype of P. fluorescens appears to be independent of the motility of the bacteria. The apoptotic effect of P. fluorescens, determined by morphological (nuclear condensation) and biochemical (induction of nitric oxide synthase activity) indicators, correlated well with its binding activity on glial cells. In contrast, there was a clear dissociation between maximum binding and maximal necrotic action (measured by the release of lactate dehydrogenase) observed with bacteria grown at 19 degrees C. As suggested by capillary electrophoresis analysis, the differences in apoptotic effects may be related to variations in the molecular structure of LPS originating from bacteria grown at low and high temperatures, whereas the necrotic effect, which was maximal at the optimum temperature for the secretion of exoenzymes, could reflect variations in the metabolic activity of bacteria.

Outbreak of Pseudomonas fluorescens bacteremia among oncology patients

From 7 to 24 March 1997, four patients developed Pseudomonas fluorescens bacteremia at the hospital; one on the oncology ward and the other three in the chemotherapy room. These patients all had underlying malignancies and had the Port-A-Cath (Smiths Industries Medical Systems, Deltec, Inc., St. Paul, Minn.) implants. Three patients had primary bacteremia, and one had Port-A-Cath-related infection. None of these patients had received a blood transfusion before the episodes of bacteremia. All patients recovered: two received antimicrobial agents with in vitro activity against the isolates, and the other two did not have any antibiotic treatment. A total of eight blood isolates were recovered from these patients during the febrile episodes that occurred several minutes after the infusion of chemotherapeutic agents via the Port-A-Cath. These isolates were initially identified as P. fluorescens or Pseudomonas putida (four), Burkholderia (Ralstonia) pickettii (three), and a non-glucose-fermenting gram-negative bacillus (one) by routine biochemical methods and the Vitek GNI card. These isolates were later identified as P. fluorescens on the basis of the characteristic cellular fatty acid chromatogram and the results of supplemental biochemical tests. The identification of identical antibiotypes by the E test and the random amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates showed that the outbreak was caused by a single clone of P. fluorescens. Surveillance cultures of the possibly contaminated infusion fluids and disinfectants, which were performed 7 days after recognition of the last infected patient, failed to isolate P. fluorescens. This report of a small outbreak caused by P. fluorescens suggests that timely, accurate identification of unusual nosocomial pathogens is crucial for early initiation of an epidemiological investigation and timely control of an outbreak.

Rate of growth of Pseudomonas fluorescens in donated blood

AIMS

To examine how delayed refrigeration of blood affects the growth of Pseudomonas fluorescens, one of the two most important causes of sepsis resulting from transfusion of contaminated blood.

METHODS

Two donations of whole blood were each divided into three aliquots and inoculated with 5-10 cfu/ml of a P fluorescens strain from a case of transfusion associated sepsis. From each donation, one aliquot was placed at 4 degrees C, one was held at 20 degrees C for six hours prior to refrigeration and the third was held at 20 degrees C for 24 hours prior to refrigeration. Samples were aseptically withdrawn over 17 days and bacterial counts were determined using a pour plate technique.

RESULTS

The rate of growth of P fluorescens in blood at 20 degrees C was increased compared with blood at 4 degrees C. At 24 hours the aliquots held at 20 degrees C for six and 24 hours had, respectively, 174 and 29,000 cfu/ml compared with 15 cfu/ml in aliquots held at 4 degrees C. There was no evidence of increased killing of P fluorescens at the higher temperature.

CONCLUSIONS

These results suggest that blood for transfusion should be refrigerated as soon as possible after collection.

Transfusion-associated bacterial sepsis

The incidence of sepsis caused by transfusion of bacterially contaminated blood components is similar to or less than that of transfusion-transmitted hepatitis C virus infection, yet significantly exceeds those currently estimated for transfusion-associated human immunodeficiency and hepatitis B viruses. Outcomes are serious and may be fatal. In addition, transfusion of sterile allogenic blood can have generalized immunosuppressive effects on recipients, resulting in increased susceptibility to postoperative infection. This review examines the frequency of occurrence of transfusion-associated sepsis, the organisms implicated, and potential sources of bacteria. Approaches to minimize the frequency of sepsis are discussed, including the benefits and disadvantages of altering the storage conditions for blood. In addition, the impact of high levels of bacteria on the gross characteristics of erythrocyte and platelet concentrates is described. The potentials and limitations of current tests for detecting bacteria in blood are also discussed.

A survey of cold-growing gram-negative organisms isolated from the skin of prospective blood donors

The skin of the antecubital fossae of 90 subjects, chosen at random but eligible to be blood donors, was sampled using sterile swabs. This sampling was done prior to disinfection. The swabs were inoculated into a selective culture medium and 'incubated' at blood bank refrigerator temperature for a total of 6 weeks. The results show that there were a number of cold-growing Gram-negative bacilli (GNB) on the skin tested. One of the GNB carriers found was subjected to frequent testing both before and after skin disinfection. The routine skin disinfection regime for blood donors was used in an attempt to establish its effectiveness. Despite regularly being able to culture Pseudomonas fluorescens prior to swabbing, no swabs taken after disinfection showed growth. This volunteer was subjected to a skin biopsy to establish whether the skin disinfection might be simply superficial. No growth occurred in the medium into which biopsy tissue, after disinfection, was inoculated. We conclude that although GNB may be present on donors' skin, the disinfection procedure, as used by us prior to donation, was effective.

Post transfusion septicaemia 1980-1989: importance of donor arm cleansing

AIMS

To determine the prevalence of Pseudomonas fluorescens on the arms of blood donors, and to elucidate one possible cause for its predominance (60% of cases during 1980-89) in exogenous post transfusion septicaemia (PTS).

METHODS

Skin swabs were taken from the arms of 782 blood donors and cultured on to heated blood agar. After incubation, Oxidase reagent and the Gram stain were used to select non-fermentative Gram negative rods, which were then subcultured and identified using the Analytical Profile System (API) 20 NE system.

RESULTS

Non-fermentative Gram negative rods were found on the arms of 11.7% of donors, Pseudomonas spp on 1.0%, and Ps fluorescens on the arms of 0.3% of donors.

CONCLUSIONS

This evidence emphasises the absolute requirement for efficient skin cleansing of blood donors' arms to minimise the risk of exogenous PTS.

Yersinia enterocolitica in donor blood: a case report and review

Routine sterility control of a unit of leukocyte-depleted erythrocyte concentrate yielded growth of Yersinia enterocolitica serotype O:3. Plasma of the donor showed a high titer of agglutinins against the homologous organism. Although the donor was apparently well at the time of donation, he had a history of protracted terminal ileitis treated by surgery. The recipient of the contaminated blood was taking broad-spectrum antibiotics and did not experience any adverse effect. Fourteen other cases of transfusion-associated yersiniosis have been reported.

Transfusion transmitted infectious agents, excluding hepatitis and human immunodeficiency viruses

A number of viruses, parasites and bacteria can be transmitted by blood. Blood seronegative for cytomegalovirus (CMV), effectively prevents CMV infection in seronegative bone marrow recipients. Such blood is available at larger blood transfusion services. Immune anti-CMV globulin can also be helpful in protection of transplant recipients. Human T-lymphotropic virus, type 1 (HTLV-1) causing leukemia and myelopathy can also be transmitted by blood. Blood banks are considering donor screening in areas where the prevalence of this virus is significant. Parvoviruses that may cause crises in haemolytic anaemias present a potential hazard of transfusion. Malaria and syphilis are currently not very important infectious complications of transfusion, whereas prolonged storage of platelets has reemphasised the risk of bacterial growth in blood products.