Cardiac Macrophage Density in Covid-19 Infection: Relationship to Myocyte Necrosis and Acute Lung Injury

SARS-Cov-2 infection is not limited to the respiratory tract and can involve other organs including the heart, blood vessels, kidneys, liver, gastrointestinal tract, placenta, and skin. Covid-19 patients with cardiac involvement usually have higher morbidity and mortality compared to those without cardiac involvement. The frequency and the specificity of the myocardial pathological changes in patients who die after documented infection with SARS-Cov-2 is uncertain. Macrophages can be found in the normal heart (interstitium, around the endothelial cells and in the epicardial adipose tissue), and they are considered part of the major immune cell population in the heart. In this case-control autopsy study, we compare the gross and microscopic cardiac findings, and the available clinical characteristics between a group of 10 Covid-19 decedents and a control group of 20 patients who died with non-SARS-Cov-2 severe bronchopneumonia and/or diffuse alveolar damage. The objectives of this semi-quantitative study are to study single myocyte necrosis and its relation to the strain on the heart caused by lung injury as a causative mechanism, and to study the density of myocardial and epicardial macrophages in Covid-19 hearts in comparison to the control group, and in Covid-19 hearts with single myocyte necrosis in comparison to Covid-19 hearts without single myocyte necrosis. Lymphocytic myocarditis was not identified in any of the hearts from the Covid-19 or the control group. Single myocyte necrosis is more frequent in the Covid-19 group compared to the control group, suggesting that it is unrelated to the strain on the heart caused by underlying lung injury. The density of the macrophages in the epicardium and myocardium in the hearts of the Covid-19 group is higher compared to those in the control group. The density of epicardial macrophages is higher in the Covid-19 hearts with single myocyte necrosis than in those without. These observations contribute to our increasing appreciation of the role of macrophages in the pathophysiologic response to infection by SARS-CoV-2.

Leukostasis aggravated by red blood cell transfusion in a chronic lymphocytic leukemia patient

Introduction/Objective

Leukostasis/symptomatic hyperleukocytosis is commonly seen in acute leukemias and is characterized by high blast counts and symptoms of decreased tissue perfusion with a one-week mortality of 20-40%, if left untreated. It is a rare complication in chronic lymphocytic leukemia (CLL) and is seen in CLL patients with white blood cell (WBC) counts > 500x10^9/L. Studies have shown that transfusion of blood products prior to decreasing the WBC count may lead to increased blood viscosity and worsen leukostasis. We report a CLL patient with a lower WBC count presenting with symptoms of leukostasis, further worsened by a red blood cell (RBC) transfusion prior to leukapheresis.

Methods/Case Report

A 73-year-old male with history of CLL for 5 years, hypertension and chronic kidney disease presented with acute dyspnea for 1 day. The WBC count was 208x10^9/L, hemoglobin was 6.5 g/dL, troponin I was 1.554 ng/mL, creatinine was 1.68 mg/dL and chest x-ray showed bilateral interstitial lung edema. The patient was diagnosed with acute hypoxic respiratory failure, acute kidney injury and myocardial infarction due to leukostasis. He received RBC transfusion, shortly after which his dyspnea worsened. There were no other signs or symptoms that could suggest a transfusion reaction. A single leukapheresis was performed following which there was a significant improvement in symptoms with a drop in WBC count to 123.1x10^9/L and creatinine to 1.3 mg/dL.

Results (if a Case Study enter NA)

NA

Conclusion

CLL may present with symptomatic hyperleukocytosis at lower leukocyte counts than has been described in the literature. Symptoms due to leukostasis can be precipitated/worsened by transfusion of blood products due to increased blood viscosity. It is critical to identify the signs and symptoms of this medical emergency as prompt diagnosis and management with leukapheresis significantly reduces the leukocyte count and blood products should be transfused slowly during or after leukapheresis.

Changes in the Serum Metabolome of Patients Treated With Broad-Spectrum Antibiotics

Background:

The gut microbiome (GMB) generates numerous small chemicals that can be absorbed by the host and variously biotransformed, incorporated, or excreted. The resulting metabolome can provide information about the state of the GMB, of the host, and of their relationship. Exploiting this information in the service of biomarker development is contingent on knowing the GMB-sensitivity of the individual chemicals comprising the metabolome. In this regard, human studies have lagged far behind animal studies. Accordingly, we tested the hypothesis that serum levels of chemicals unequivocally demonstrated to be GMB-sensitive in rodent models would also be affected in a clinical patient sample treated with broad spectrum antibiotics.

Methods:

We collected serum samples from 20 hospitalized patients before, during, and after treatment with broad-spectrum antibiotics. We also collected samples from 5 control patients admitted to the hospital but not prescribed antibiotics. We submitted the samples for a non-targeted metabolomic analysis and then focused on chemicals known to be affected both by germ-free status and by antibiotic treatment in the mouse and/or rat.

Results:

Putative identification was obtained for 499 chemicals in human serum. An aggregate analysis did not show any time x treatment interactions. However, our literature search identified 10 serum chemicals affected both by germ-free status and antibiotic treatment in the mouse or rat. Six of those chemicals were measured in our patient samples and additionally met criteria for inclusion in a focused analysis. Serum levels of 5 chemicals (p-cresol sulfate, phenol sulfate, hippurate, indole propionate, and indoxyl sulfate) declined significantly in our group of antibiotic-treated patients but did not change in our patient control group.

Conclusions:

Broad-spectrum antibiotic treatment in patients lowered serum levels of selected chemicals previously demonstrated to be GMB-sensitive in rodent models. Interestingly, all those chemicals are known to be uremic solutes that can be derived from aromatic amino acids (L-phenylalanine, L-tyrosine, or L-tryptophan) by anaerobic bacteria, particularly Clostridial species. We conclude that judiciously selected serum chemicals can reliably detect antibiotic-induced suppression of the GMB in man and thus facilitate further metabolome-based biomarker development.

Absolute Immature Platelet Counts Suggest Platelet Production Suppression during Complicated Relapsing Thrombotic Thrombocytopenic Purpura

Absolute immature platelet counts (A-IPC) aid in diagnosis and treatment follow-up in thrombotic thrombocytopenic purpura (TTP). A-IPC was used to follow a patient on mycophenolate mofetil (MMF) maintenance therapy treated with a prolonged therapeutic plasma exchange (TPE) regimen for relapsing TTP. On admission, the platelet (PLT) count was 95 × 109/L declining to 14 × 109/L in 5 days. Daily TPE was initiated for suspected TTP, and MMF was discontinued. A-IPC and PLT count were 1 × 109/L and 14 × 109/L, respectively, prior to first TPE. A-IPC improved to 3.2 × 109/L with 1 TPE, and on day 5, A-IPC and PLT count were 7.5 × 109/L and 218 × 109/L, respectively. On day 6, A-IPC and PLT count decreased to 4.8 × 109/L and 132 × 109/L further worsening to 0.4 × 109/L and 13 × 109/L, respectively. ADAMTS13 activity remained <5% with an inhibitor; counts did not recover. Initial improvement followed by rapidly declining A-IPC despite therapy suggested production suppression. In TTP, A-IPC may aid in establishing early therapy effects over PLT production.

Bacterial contamination and septic transfusion reaction rates associated with platelet components before and after introduction of primary culture: experience at a US Academic Medical Center 1991 through 2017

BACKGROUND

The high incidence of septic transfusion reactions (STRs) led to testing being mandated by AABB from 2004. This was implemented by primary culture of single-donor apheresis platelets (APs) from 2004 and prestorage pooled platelets (PSPPs) from 2007.

STUDY DESIGN/METHODS

Platelet (PLT) aliquots were cultured at issue and transfusion reactions evaluated at our hospital. Bacterial contamination and STR rates (shown as rates per million transfusions in Results) were evaluated before and after introduction of primary culture by blood centers that used a microbial detection system (BacT/ALERT, bioMerieux) or enhanced bacterial detection system (eBDS, Haemonetics).

RESULTS

A total of 28,457 PLTs were cultured during pre-primary culture periods (44.7% APs; 55.3% at-issue pooled PLTs [AIPPs]) and 97,595 during post-primary culture periods (79.3% APs; 20.7% PSPPs). Forty-three contaminated units were identified in preculture and 34 in postculture periods (rates, 1511 vs. 348; p < 0.0001). Contamination rates of APs were significantly lower than AIPPs in the preculture (393 vs. 2415; p < 0.0001) but not postculture period compared to PSPPs (387 vs. 198; p = 0.9). STR rates (79 vs. 90; p = 0.98) were unchanged with APs but decreased considerably with pooled PLTs (826 vs. 50; p = 0.0006). Contamination (299 vs. 324; p = 0.84) and STR rates (25 vs. 116; p = 0.22) were similar for PLTs tested by BacT/ALERT and eBDS primary culture methods. A change in donor skin preparation method in 2012 was associated with decreased contamination and STR rates.

CONCLUSION

Primary culture significantly reduced bacterial contamination and STR associated with pooled but not AP PLTs. Measures such as secondary testing near time of use or pathogen reduction are needed to further reduce STRs.

Immune Signatures Associated With Clonal Isotype Switch After Autologous Stem Cell Transplantation for Multiple Myeloma

BACKGROUND

High-dose chemotherapy and autologous stem cell transplantation (ASCT) are integral components of the overall treatment for patients with multiple myeloma (MM) aged ≤ 65 years. The emergence of oligoclonal immunoglobulin bands (ie, immunoglobulins differing from those originally identified at diagnosis [termed clonal isotype switch (CIS)]) has been reported in patients with MM after high-dose chemotherapy followed by autologous stem cell transplantation. However, the clinical relevance and the correlation with immune reconstitution remains unclear.

PATIENTS AND METHODS

Patients with MM who had undergone ASCT from 2007 to 2016 were included in the present study. The percentage of natural killer cells, B-cells, and T-cells was measured using flow cytometry in pre- and post-ASCT bone marrow samples. CIS was defined as the appearance of a new serum monoclonal spike on serum protein electrophoresis and immunofixation that differed from original heavy or light chain detected at diagnosis.

RESULTS

A retrospective analysis of 177 patients with MM who had undergone ASCT detected CIS in 39 (22%). CIS after ASCT correlated with improved progression-free survival (52.2 vs. 36.6 months; P = .21) and overall survival (75.1 vs. 65.4 months; P = .021). Patients with a relapse had an isotype that differed from a CIS, confirming the benign nature of this phenomenon. CIS was also associated with lower CD8 T-cell percentages and a greater CD4/CD8 ratio (2.8 vs. 0.2; P = .001) compared with patients who did not demonstrate a CIS, suggestive of more profound T-cell immune reconstitution in this group.

CONCLUSION

Taken together, our data have demonstrated that a CIS is a benign phenomenon and correlates with a reduced disease burden and enriched immune repertoire beyond the B-cell compartment.

Compound Heterozygosity for Hb D-Ibadan (HBB: c.263C>A) and Hb C (HBB: c.19G>A)

We report an individual with a compound heterozygosity for Hb D-Ibadan (HBB: c.263C>A) and Hb C (HBB: c.19G>A), a hemoglobin (Hb) combination not previously identified. The compound hemoglobinopathy was detected in a young woman during routine prenatal screening. Variant Hbs were identified and confirmed by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) followed by Sanger DNA sequencing. Hb D-Ibadan was present in significant excess over Hb C (70.3 to 24.4%). A complete blood count (CBC) revealed moderate microcytosis with slight anemia. The history suggests the Hb combination is clinically silent. The findings indicate the compound hemoglobinopathy demonstrates thalassemia minor-like red cell indices with an unequal distribution of the variant Hbs. Comparison with other Hb D-like heterozygous conditions is reviewed.

Laboratory Assessment of Anemia

Anemia is one of the most common health problems in both industrialized and developing countries. It has been recognized by the World Health Organization as an important disorder leading to significant health care burden. Laboratory testing plays a significant role in the diagnosis of most types of anemia since the clinical diagnosis may not always be straightforward, especially with multiple underlying conditions. Once the existence of anemia is established, the cause must be determined to enable selection of a specific and effective therapy. Various hematologic parameters and biochemical tests can be used in combination with patient clinical history to identify the most likely causes of anemia.

Effect of Surotomycin, a Novel Cyclic Lipopeptide Antibiotic, on Intestinal Colonization with Vancomycin-Resistant Enterococci and Klebsiella pneumoniae in Mice

Surotomycin (formerly called CB-183,315) is a novel, orally administered cyclic lipopeptide antibacterial in development for the treatment of Clostridium difficile infection (CDI) that has potent activity against vancomycin-resistant enterococci (VRE) but limited activity against Gram-negative bacilli, including Bacteroides spp. We used a mouse model to investigate the impact of surotomycin exposure on the microbiome, and to test the consequences of the disruption on colonization by vancomycin-resistant enterococci (VRE) and extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP), in comparison with the effects of oral vancomycin and metronidazole. Mice (8 per group) received saline, vancomycin, metronidazole, or surotomycin through an orogastric tube daily for 5 days and were challenged with 10(5) CFU of VRE or ESBL-KP administered through an orogastric tube on day 2 of treatment. The concentrations of the pathogens in stool were determined during and after treatment by plating on selective media. A second experiment was conducted to determine if the antibiotics would inhibit established VRE colonization. In comparison to controls, oral vancomycin promoted VRE and ESBL-KP overgrowth in stool (8 log10 to 10 log10 CFU/g; P < 0.001), whereas metronidazole did not (<4 log10 CFU/g; P > 0.5). Surotomycin promoted ESBL-KP overgrowth (>8 log10 CFU/g; P, <0.001 for comparison with saline controls) but not VRE overgrowth. Surotomycin suppressed preexisting VRE colonization, whereas metronidazole and vancomycin did not. These results suggest that treatment of CDI with surotomycin could reduce levels of VRE acquisition and overgrowth from those with agents such as vancomycin and metronidazole. However, surotomycin and vancomycin may promote colonization by antibiotic-resistant Gram-negative bacilli.

Evaluation of an enclosed ultraviolet-C radiation device for decontamination of mobile handheld devices

Mobile handheld devices used in health care settings may become contaminated with health care-associated pathogens. We demonstrated that an enclosed ultraviolet-C radiation device was effective in rapidly reducing methicillin-resistant Staphylococcus aureus, and with longer exposure times, Clostridium difficile spores, on glass slides and reducing contamination on in-use mobile handheld devices.

Do piperacillin/tazobactam and other antibiotics with inhibitory activity against Clostridium difficile reduce the risk for acquisition of C. difficile colonization?

Background

Systemic antibiotics vary widely in in vitro activity against Clostridium difficile. Some agents with activity against C. difficile (e.g., piperacillin/tazobactam) inhibit establishment of colonization in mice. We tested the hypothesis that piperacillin/tazobactam and other agents with activity against C. difficile achieve sufficient concentrations in the intestinal tract to inhibit colonization in patients.

Methods

Point-prevalence culture surveys were conducted to compare the frequency of asymptomatic rectal carriage of toxigenic C. difficile among patients receiving piperacillin/tazobactam or other inhibitory antibiotics (e.g. ampicillin, linezolid, carbapenems) versus antibiotics lacking activity against C. difficile (e.g., cephalosporins, ciprofloxacin). For a subset of patients, in vitro inhibition of C. difficile (defined as a reduction in concentration after inoculation of vegetative C. difficile into fresh stool suspensions) was compared among antibiotic treatment groups.

Results

Of 250 patients, 32 (13 %) were asymptomatic carriers of C. difficile. In comparison to patients receiving non-inhibitory antibiotics or prior antibiotics within 90 days, patients currently receiving piperacillin/tazobactam were less likely to be asymptomatic carriers (1/36, 3 versus 7/36, 19 and 15/69, 22 %, respectively; P = 0.024) and more likely to have fecal suspensions with in vitro inhibitory activity against C. difficile (20/28, 71 versus 3/11, 27 and 4/26, 15 %; P = 0.03). Patients receiving other inhibitory antibiotics were not less likely to be asymptomatic carriers than those receiving non-inhibitory antibiotics.

Conclusions

Our findings suggest that piperacillin/tazobactam achieves sufficient concentrations in the intestinal tract to inhibit C. difficile colonization during therapy.

Contamination of Health Care Personnel During Removal of Personal Protective Equipment

IMPORTANCE

Contamination of the skin and clothing of health care personnel during removal of personal protective equipment (PPE) contributes to dissemination of pathogens and places personnel at risk for infection.

OBJECTIVES

To determine the frequency and sites of contamination on the skin and clothing of personnel during PPE removal and to evaluate the effect of an intervention on the frequency of contamination.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a point-prevalence study and quasi-experimental intervention from October 28, 2014, through March 31, 2015. Data analysis began November 17, 2014, and ended April 21, 2015. Participants included a convenience sample of health care personnel from 4 Northeast Ohio hospitals who conducted simulations of contaminated PPE removal using fluorescent lotion and a cohort of health care personnel from 7 study units in 1 medical center that participated in a quasi-experimental intervention that included education and practice in removal of contaminated PPE with immediate visual feedback based on fluorescent lotion contamination of skin and clothing.

MAIN OUTCOMES AND MEASURES

The primary outcomes were the frequency and sites of contamination on skin and clothing of personnel after removal of contaminated gloves or gowns at baseline vs after the intervention. A secondary end point focused on the correlation between contamination of skin with fluorescent lotion and bacteriophage MS2, a nonpathogenic, nonenveloped virus.

RESULTS

Of 435 glove and gown removal simulations, contamination of skin or clothing with fluorescent lotion occurred in 200 (46.0%), with a similar frequency of contamination among the 4 hospitals (range, 42.5%-50.3%). Contamination occurred more frequently during removal of contaminated gloves than gowns (52.9% vs 37.8%, P = .002) and when lapses in technique were observed vs not observed (70.3% vs 30.0%, P < .001). The intervention resulted in a reduction in skin and clothing contamination during glove and gown removal (60.0% before the intervention vs 18.9% after, P < .001) that was sustained after 1 and 3 months (12.0% at both time points, P < .001 compared with before the intervention). During simulations of contaminated glove removal, the frequency of skin contamination was similar with fluorescent lotion and bacteriophage MS2 (58.0% vs 52.0%, P = .45).

CONCLUSIONS AND RELEVANCE

Contamination of the skin and clothing of health care personnel occurs frequently during removal of contaminated gloves or gowns. Educational interventions that include practice with immediate visual feedback on skin and clothing contamination can significantly reduce the risk of contamination during removal of PPE.

An intervention to reduce health care personnel hand contamination during care of patients with Clostridium difficile infection

In a quasi-experimental study, an educational intervention to improve the technique for personal protective equipment (PPE) removal in conjunction with disinfection of gloves before removal of PPE reduced acquisition of Clostridium difficile spores on the hands of health care personnel caring for patients with C difficile infection.

Sustained increase in resident meal time hand hygiene through an interdisciplinary intervention engaging long-term care facility residents and staff

Hand hygiene by patients may prevent acquisition and dissemination of health care-associated pathogens, but limited efforts have been made to engage patients in hand hygiene interventions. In a long-term care facility, we found that residents were aware of the importance of hand hygiene, but barriers, such as inaccessible products or difficult to use products, limited compliance. A dramatic and sustained improvement in meal time hand hygiene was achieved through engagement of staff and residents.

Tigecycline exhibits inhibitory activity against Clostridium difficile in the intestinal tract of hospitalised patients

No new acquisition of Clostridium difficile occurred among 12 hospitalised patients receiving tigecycline, and pre-existing colonisation was reduced to undetectable levels in 2 patients. Moreover, 91% of stool suspensions obtained during tigecycline therapy exhibited inhibitory activity against C. difficile. These results suggest that tigecycline achieves sufficient concentrations to inhibit intestinal colonisation by C. difficile.

A Clostridium difficile Infection (CDI) Stewardship Initiative Improves Adherence to Practice Guidelines for Management of CDI

A Clostridium difficile infection (CDI) stewardship initiative reduced inappropriate prescription of empirical CDI therapy and improved timeliness of treatment and adherence to clinical practice guidelines for management of CDI. The initiative required minimal resources and could easily be incorporated into traditional antimicrobial stewardship programs.

Outbreak of Fluoroquinolone-Resistant Escherichia coli Infections after Transrectal Ultrasound—Guided Biopsy of the Prostate

Design.

We conducted an investigation after identifying a cluster of 4 serious infections following transrectal ultrasound–guided biopsy of the prostate (TRUBP) during a 2-month period.

Setting.

veterans Affairs medical center.

Patients.

Patients with urinary tract infection (UTI) after TRUBP and time-matched controls with no evidence of infection.

Methods.

The incidence of UTI within 30 days after TRUBP was calculated from 2002 through 2010. We evaluated the correlation between infection with fluoroquinolone-resistant gram-negative bacilli (GNB) and fluoroquinolone resistance in outpatient Escherichia coli urinary isolates and performed a case-control study to determine risk factors for infection with fluoroquinolone-resistant GNB. Processes for TRUBP prophylaxis, procedures, and equipment sterilization were reviewed.

Results.

An outbreak of UTI due to fluoroquinolone-resistant E. coli after TRUBP began 2 years before the cluster was identified and was correlated with increasing fluoroquinolone resistance in outpatient E. coli. No deficiencies were identified in equipment processing or biopsy procedures. Fluoroquinolone-resistant E. coli UTI after TRUBP was independently associated with prior infection with fluoroquinolone-resistant GNB (adjusted odds ratio, 20.8; P = .005). A prediction rule including prior UTI, hospitalization in the past year, and previous infection with fluoroquinolone-resistant GNB identified only 17 (49%) of 35 cases.

Conclusions.

The outbreak of fluoroquinolone-resistant E. coli infections after TRUBP closely paralleled rising rates of fluoroquinolone resistance among outpatient E. coli isolates. The delayed detection of the outbreak and the absence of sensitive predictors of infection suggest that active surveillance for infection after TRUBP is necessary in the context of increasing fluoroquinolone resistance in the United States.

Efficacy of Dilute Hypochlorite Solutions and an Electrochemically Activated Saline Solution Containing Hypochlorous Acid for Disinfection of Methicillin-Resistant Staphylococcus aureus in a Pig Skin Model

Recurrent skin and soft-tissue infections (SSTIs) due to Staphylococcus aureus are a common problem in children and adults. Many of these SSTIs are caused by a community-associated methicillin-resistant S. aureus (MRSA) strain designated USA300. Dilute bleach baths are commonly used as part of decolonization regimens for recurrent SSTI, particularly in children. However, limited data are available on the microbiological efficacy of dilute bleach on skin, and optimal concentrations are unknown. Recent practice guidelines for MRSA from the Infectious Diseases Society of America recommend a teaspoon of household bleach per gallon of bath water (1.3 μL/mL or a quarter cup per quarter tub of water) for 15 minutes twice weekly. On the basis of in vitro data, Fisher et al suggested that a higher concentration (2.5 μL/mL or a half cup per quarter tub of water) might be more effective (more than a 3-log reduction in MRSA in 5 minutes versus a 2-log reduction for a 1.2-μL/mL concentration). In contrast, more dilute bleach solutions (eg, a quarter cup of 6% sodium hypochlorite per bathtub full of water) for 5 days in combination with intranasal mupirocin were effective for eradication of colonization in a recent randomized trial, but 29% of patients in the mupirocin/bleach bath group developed recurrent colonization within 4 months. Here, we used a pig skin model to examine the effectiveness of various concentrations of dilute bleach solution and an electrochemically activated saline solution containing 0.025% hypochlorous acid (Vashe; PuriCore) for disinfection of MRSA on skin. Vashe is safe for use on skin and is commercially available as a wound care product.

Modification of Antimicrobial Prophylaxis Based on Rectal Culture Results to Prevent Fluoroquinolone-Resistant Escherichia coli Infections after Prostate Biopsy

For patients undergoing transrectal ultrasound-guided biopsy of the prostate (TRUBP), use of rectal screening culture results to guide antimicrobial prophylaxis was effective for prevention of fluoro-quinolone-resistant Escherichia coli infections. In practice, elimination of infections after TRUBP required the rectal screening protocol and addition of gentamicin for patients missing prior screening.

Evaluation of a sporicidal peracetic acid/hydrogen peroxide-based daily disinfectant cleaner

OxyCide Daily Disinfectant Cleaner, a novel peracetic acid/hydrogen peroxide-based sporicidal disinfectant, was as effective as sodium hypochlorite for in vitro killing of Clostridium difficile spores, methicillin-resistant Staphylococcus aureus, and vancomcyin-resistant enterococci. OxyCide was minimally affected by organic load and was effective in reducing pathogen contamination in isolation rooms.

Evaluation of patients' skin, environmental surfaces, and urinary catheters as sources for transmission of urinary pathogens

In hospitalized patients with urinary tract infection or asymptomatic bacteriuria, urinary pathogens frequently contaminate skin, high-touch environmental surfaces, and urinary catheters. Contamination is more common in patients with a urinary catheter in place and with gram-positive pathogens. Patients' skin and environmental surfaces may provide an important source for transmission of urinary pathogens.

A case study of a real-time evaluation of the risk of disease transmission associated with a failure to follow recommended sterilization procedures

BACKGROUND

Failures to follow recommendations for reprocessing of surgical instruments may place patients at risk for exposure to pathogenic microorganisms. When such failures occur, medical facilities often face considerable uncertainty and challenges in assessing the actual risks of disease transmission.

METHODS

In 2011, staff at an Ohio hospital determined that surgical instruments inside a Steriset Container had inadvertently been autoclaved on a gravity cycle rather than on the recommended pre-vacuum cycle, potentially exposing 72 patients who underwent surgery with the instruments to risk of infection. To provide an assessment of the level of risk, we tested the effectiveness of the machine washer/disinfector step and of the sterilization process inside the Steriset Container on the gravity cycle for killing of Geobacillus stearothermophilus spores, Clostridium difficile spores, and methicillin-resistant Staphylococcus aureus (MRSA). Based on the test results, the risk of transmission of MRSA by the instruments was calculated and the risk of transmission of hepatitis B virus was estimated.

RESULTS

The machine washer/disinfector consistently reduced MRSA recovery by a factor of 1:100,000. The sterilization process inside the Steriset Container consistently reduced MRSA concentrations by a factor of >1:10,000,000 and killed 105C. difficile spores and 105G. stearothermophilus spores. The risk of MRSA transmission due to the incident was calculated to be 1 in 100 trillion.

CONCLUSIONS

The risk for transmission of infection due to the failure to follow recommended sterilization processes was negligible based upon complete killing of G. stearothermophilus biological indicator spores, C. difficile spores, and MRSA under conditions that replicated the incident where proper procedures were not followed. Such real-time assessments of the risks associated with specific incidents may provide evidence-based information that can be used to inform decisions regarding disclosure of the incident to patients.

Pseudo-outbreak of Klebsiella oxytoca spontaneous bacterial peritonitis attributed to contamination of multidose vials of culture medium supplement

OBJECTIVE

To determine the source of a cluster of Klebsiella oxytoca isolates cultured from peritoneal fluid of 3 patients with cirrhosis on a single day.

DESIGN

Outbreak investigation and before-after study.

SETTING

A Veterans Affairs medical center.

METHODS

Epidemiologic investigation, analysis of antimicrobial susceptibility testing results and molecular typing of K. oxytoca isolates with repetitive sequence-based polymerase chain reaction (rep-PCR), review of microbiology laboratory procedures for processing peritoneal fluid cultures, and comparison of peritoneal fluid contamination rates 18 months before and after modification of laboratory procedures for culturing peritoneal fluid.

RESULTS

Each of the peritoneal fluid samples that grew K. oxytoca was inoculated into blood culture bottles by different clinicians at different hospital locations. None of the patients had clinical findings suggestive of peritonitis or elevated polymorphonuclear cell counts in peritoneal fluid (range, 3-25 cells/μL). Molecular typing with rep-PCR demonstrated that the K. oxytoca isolates were genetically related (greater than 95% similarity). Laboratory procedures included the routine addition of a culture medium supplement of yeast extract and dextrose from a multidose vial into blood culture bottles with peritoneal fluid. After discontinuing use of the culture medium supplement, there was a marked reduction in the number of peritoneal fluid cultures deemed as contaminants (14.3% vs 0.9%; [Formula: see text]).

CONCLUSION

A pseudo-outbreak of K. oxytoca peritonitis and high rates of contamination of peritoneal fluid were attributable to contamination of a multidose culture medium supplement. This article highlights the importance of discouraging the use of multidose vials in all clinical settings.

An environmental disinfection odyssey: evaluation of sequential interventions to improve disinfection of Clostridium difficile isolation rooms

OBJECTIVE. Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. We evaluated the impact of sequential cleaning and disinfection interventions by culturing high-touch surfaces in CDI rooms after cleaning. DESIGN. Prospective intervention. SETTING. A Veterans Affairs hospital. INTERVENTIONS. During a 21-month period, 3 sequential tiered interventions were implemented: (1) fluorescent markers to provide monitoring and feedback on thoroughness of cleaning facility-wide, (2) addition of an automated ultraviolet radiation device for adjunctive disinfection of CDI rooms, and (3) enhanced standard disinfection of CDI rooms, including a dedicated daily disinfection team and implementation of a process requiring supervisory assessment and clearance of terminally cleaned CDI rooms. To determine the impact of the interventions, cultures were obtained from CDI rooms after cleaning and disinfection. RESULTS. The fluorescent marker intervention improved the thoroughness of cleaning of high-touch surfaces (from 47% to 81% marker removal; P < .0001). Relative to the baseline period, the prevalence of positive cultures from CDI rooms was reduced by 14% (P=.024), 48% (P <.001), and 89% (P=.006) with interventions 1, 2, and 3, respectively. During the baseline period, 67% of CDI rooms had positive cultures after disinfection, whereas during interventions periods 1, 2, and 3 the percentages of CDI rooms with positive cultures after disinfection were reduced to 57%, 35%, and 7%, respectively. CONCLUSIONS. An intervention that included formation of a dedicated daily disinfection team and implementation of a standardized process for clearing CDI rooms achieved consistent CDI room disinfection. Culturing of CDI rooms provides a valuable tool to drive improvements in environmental disinfection.

Does organic material on hospital surfaces reduce the effectiveness of hypochlorite and UV radiation for disinfection of Clostridium difficile?

An organic load of 5%-10% fetal calf serum significantly reduced hypochlorite and UV radiation killing of Clostridium difficile spores, but organic material collected from hospital surfaces did not affect hypochlorite and only modestly affected UV killing of spores. Hypochlorite reduced aerobic microorganisms on unclean surfaces with no wiping.

Evaluation of a commercial real-time polymerase chain reaction assay for detection of environmental contamination with Clostridium difficile

Contaminated environmental surfaces are an important source for transmission of Clostridium difficile. However, there are no efficient and easy methods to assess contamination. The performance of a commercial real-time polymerase chain reaction (PCR) assay was evaluated for detection of environmental toxigenic C. difficile in comparison with anaerobic culture followed by toxin testing of isolates. For 66 sites sampled, PCR had a sensitivity of 17.39%, specificity 100%, positive predictive value 100% and negative predictive value 69.35%. Increasing the PCR cycle threshold (CT) value to 45 increased sensitivity to 52% without decreasing specificity. The commercial PCR assay is not sufficiently sensitive for environmental monitoring, but improved sensitivity might be possible through CT value modification.

Appropriateness of empiric therapy in patients with suspected Clostridium difficile infection

OBJECTIVE

The objective of this study was to test the hypothesis that many patients with suspected Clostridium difficile infection (CDI) receive inappropriate empiric therapy and/or receive continued therapy despite negative test results.

METHODS

We performed a 3 month prospective cohort study at the Cleveland Veteran Affairs Medical Center to assess the appropriateness of empiric CDI therapy for all patients with stool samples submitted for CDI testing. Empiric therapy for CDI was considered appropriate if patients with suspected CDI had findings suggestive of severe or complicated illness.

RESULTS

Of 251 patients tested for CDI, 53 (21%) received empiric treatment, including 45 (85%) treated with metronidazole and 8 (15%) treated with vancomycin. Of the 53 empirical therapy regimens, only 20 (38%) were deemed appropriate based on criteria for severe or severe, complicated CDI and 39 (74%) had negative laboratory testing for CDI. Twenty-one of 39 (54%) patients with negative testing were continued on therapy for three or more days despite the negative results. The key limitations of the study are the fact that it was conducted in a single institution and had a small sample size.

CONCLUSION

In our facility, empiric treatment for CDI was common and more than half of empirical treatment was deemed inappropriate because patients did not meet criteria for severe CDI. Because CDI therapy may be associated with adverse effects, there is a need for interventions to improve the appropriateness of empiric CDI treatment.

Outpatient healthcare settings and transmission of Clostridium difficile

BACKGROUND

Recent reports suggest that community-associated Clostridium difficile infection (CDI) (i.e., no healthcare facility admission within 90 days) may be increasing in frequency. We hypothesized that outpatient clinics could be an important source for acquisition of community-associated CDI.

METHODS

We performed a 6-month prospective study of CDI patients to determine frequency of and risk factors for skin and environmental shedding during outpatient visits and to derive a prediction rule for positive cultures. We performed a point-prevalence culture survey to assess the frequency of C. difficile contamination in outpatient settings and evaluated the frequency of prior outpatient visits in patients with community-associated CDI.

RESULTS

Of 67 CDI patients studied, 54 (81%) had 1 or more outpatient visits within 12 weeks after diagnosis. Of 44 patients cultured during outpatient visits, 14 (32%) had skin contamination and 12 (27%) contaminated environmental surfaces. Decreased mobility, fecal incontinence, and treatment with non-CDI antibiotics were associated with positive cultures, whereas vancomycin taper therapy was protective. In patients not on CDI therapy, a prediction rule including incontinence or decreased mobility was 90% sensitive and 79% specific for detection of spore shedding. Of 84 clinic and emergency department rooms cultured, 12 (14%) had 1 or more contaminated environmental sites. For 33 community-associated CDI cases, 31 (94%) had an outpatient visit during the 12 weeks prior to onset of diarrhea.

CONCLUSIONS

Patients with recent CDI present a significant risk for transmission of spores during outpatient visits. The outpatient setting may be an underappreciated source of community-associated CDI cases.

Utility of an adenosine triphosphate bioluminescence assay to evaluate disinfection of Clostridium difficile isolation rooms

Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. Unfortunately, several studies have demonstrated that it is not uncommon for environmental cultures to remain positive for C. difficile after cleaning and disinfection of rooms in which a patient with CDI has been hospitalized (CDI rooms) by environmental services personnel. Cultures for C. difficile could potentially be useful to monitor disinfection of CDI rooms, but they are neither widely available nor efficient. There is a need for easy-to use and rapid methods to assess the effectiveness of CDI room disinfection. Adenosine triphosphate (ATP) bioluminescence assays provide a rapid assessment of cleaning effectiveness, because detection of ATP on surfaces indicates the presence of residual organic material (eg, bacteria, human secretions or excretions, and food). Detection of ATP is commonly used in the food and beverage industry and is increasingly being used in health care facilities to assess the adequacy of cleaning procedures. It is not known whether measurement of ATP on surfaces is useful to evaluate disinfection of CDI rooms. Here, we tested the hypothesis that low ATP readings on cleaned surfaces in CDI rooms would be predictive of negative cultures for C. difficile.

Potential for transmission of spores by patients awaiting laboratory testing to confirm suspected Clostridium difficile infection

In a prospective study of inpatients tested for Clostridium difficile infection (CDI), skin and environmental contamination were common at the time of the order for CDI testing, and there were often delays in completion of testing. Preemptive isolation of patients with suspected CDI may reduce the risk of transmission.

Utility of perirectal swab specimens for diagnosis of Clostridium difficile infection

For 139 patients tested for Clostridium difficile infection by polymerase chain reaction, the sensitivity, specificity, positive predictive value, and negative predictive value of testing perirectal swabs vs stool specimens were 95.7%, 100%, 100%, and 99.1%, respectively. For selected patients, perirectal swabs provide an accurate toxigenic C. difficile detection strategy.

Daily disinfection of high-touch surfaces in isolation rooms to reduce contamination of healthcare workers' hands

In a randomized nonblinded trial, we demonstrated that daily disinfection of high-touch surfaces in rooms of patients with Clostridium difficile infection and methicillin-resistant Staphylococcus aureus colonization reduced acquisition of the pathogens on hands after contacting high-touch surfaces and reduced contamination of hands of healthcare workers caring for the patients.