Pseudo-outbreak of Parengyodontium album related to contaminated saline used in specimen processing in the microbiology laboratory.

We report a cluster of 9 isolates of Parengyodontium album recovered from 4 patients who had surgical tissue specimens processed after dilution with a multiuse diluent saline solution. P album was also identified from a nonclinical sample on agar prepared with the same lot number of saline solution. Our epidemiological investigation revealed this to represent a pseudo-outbreak related to contaminated saline used to process specimens in the microbiology laboratory.

Atypical pneumonia testing in transplant recipients.

BACKGROUND: The incidence of atypical pneumonia among immunocompromised patients is not well characterized. Establishing a diagnosis of atypical pneumonia is challenging as positive tests must be carefully interpreted. We aimed to assess the test positivity rate and incidence of atypical pneumonia in transplant recipients. METHODS: A retrospective cohort study was conducted at the Yale New Haven Health System in Connecticut. Adults with solid organ transplant, hematopoietic stem cell transplant (HSCT), or chimeric antigen receptor T-cell, who underwent testing for atypical pathogens of pneumonia (Legionella pneumophilia, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Bordetella pertussis) between January 2016 and August 2022 were included. Positive results were adjudicated in a clinical context using pre-defined criteria. A cost analysis of diagnostic testing was performed. RESULTS: Note that, 1021 unique tests for atypical pathogens of pneumonia were performed among 481 transplant recipients. The testing positivity rate was 0.7% (n = 7). After clinical adjudication, there were three cases of proven Legionella and one case of possible Mycoplasma infection. All cases of legionellosis were in transplant recipients within 1-year post-transplantation with recently augmented immunosuppression and lymphopenia. The possible case of Mycoplasma infection was in an HSCT recipient with augmented immunosuppression. The cost of all tests ordered was $50,797.73. CONCLUSION: The positivity rate of tests for atypical pneumonia was very low in this transplant cohort. An algorithmic approach that targets testing for those with compatible host, clinical, radiographic, and epidemiologic factors, and provides guidance on test selection and test interpretation, may improve the diagnostic yield and lead to substantial cost savings.

Assessment of polymicrobial interactions in bacterial isolates from transfused platelet units associated with sepsis.

BACKGROUND: In 2019 the Centers for Disease Control and Prevention (CDC) reported a series of 4 transfusion reactions that resulted from contamination of apheresis platelet products. Products involved in all 4 cases were contaminated with Acinetobacter calcoaceticus-baumannii complex (ACBC) and in 3 products Staphylococcus saprophyticus was found as well. CDC investigation found that bacterial isolates from the cases were genetically related and suggested a common source of contamination. The contamination of blood products with ACBC is rare and polymicrobial contamination of blood products even less common. ACBC and S. saprophyticus have been observed to adhere to one another and sediment out of suspension in vitro, a process referred to as coaggregation, and we hypothesized that there was an interaction between the strains from these cases that contributed to their co-contamination of blood products. STUDY DESIGN AND METHODS: To test the hypothesis of bacterial interaction, we performed coaggregation experiments and observed the growth characteristics of ACBC and S. saprophyticus strains recovered from contaminated blood products involved in a subset of the CDC cases. RESULTS: An increase in S. saprophyticus CFU concentration was observed after several days of co-culture with ACBC in LB and plasma; however, no other findings suggested coaggregation or augmentative growth interaction between the bacterial strains. CONCLUSION: Ultimately, an interaction between ACBC and S. saprophyticus that could help explain their co-occurrence and growth in contaminated platelet units was not found; however future studies of potential interactions may be warranted.

Quality Management to Improve CSF Gram Stain Turnaround Time.

BACKGROUND: With appropriate turnaround time (TAT), cerebrospinal fluid (CSF) Gram stains can provide rapid, clinically actionable information in patients with meningitis. Monitoring CSF Gram stain TAT at our institution revealed workflow gaps that were causing result reporting delays. We then implemented a new quality management program to improve TAT. METHODS: We reviewed the TAT of all CSF specimens submitted for bacterial culture received between August 1, 2016, and July 31, 2020, and began prospectively monitoring CSF Gram stain TAT in January 2019. We then implemented the following changes in April 2019: (i) monthly reviews of TAT with staff, (ii) hand-off sheets for shift transitions, and (iii) pre- and post-shift walk throughs including centrifuge checks. RESULTS: A total of 6913 samples were included in the analysis. CSF samples with TAT > 60 min decreased from 27.3% to 9.89% (P < 0.0001), and median TAT decreased by 9 min (P < 0.0001) with significantly reduced variability. These changes were sustained throughout the follow-up period across all shifts and shift transitions. CONCLUSIONS: A new monthly quality metric allowed us to track CSF Gram stain TAT, identify barriers to TAT goals, and implement workflow changes that significantly improved TAT without the need for costly interventions.

Three is a crowd: Clinical outcomes of a twice daily versus a thrice daily metronidazole dosing strategy from a multicenter study.

This was a multicenter, retrospective study of patients with anaerobic bacteremia comparing metronidazole 500 mg every 8 h versus 500 mg every 12 h. Of 782 patients reviewed, 85 met inclusion criteria. There was no significant difference in mortality, length of stay, or escalation of therapy between dosing strategies.

Optimization of Turnaround Time for Group A Streptococcus PCR.

The use of some nucleic acid amplification tests (NAATs) for the diagnosis of group A Streptococcus (GAS) pharyngitis allows laboratories to adopt single-tiered testing without reflex culture. However, centralization may delay the delivery of actionable information to the bedside, particularly in the outpatient setting. We describe two novel workflows at our institution and their effect on in-lab turnaround time (TAT) at a tertiary care microbiology lab. Laboratory records were extracted, and relevant data were analyzed after the implementation of qualitative in vitro diagnostic testing for GAS with the Xpert Xpress Strep A assay, performed using the GeneXpert Infinity-48s. Workflow optimization steps studied included: (i) direct specimen submission to the microbiology laboratory via the pneumatic tube system and (ii) autoverification of GAS NAAT results in the laboratory information system. Between April 2018 and October 2018, 2,595 unique specimens were tested for GAS by PCR. Of these, 2,523 were included in the final analysis. Linear regression established that the total in-lab TAT was significantly reduced by direct specimen submission to the microbiology laboratory, autoverification, and processing during the night shift. We describe two workflow optimization methods that reduced the in-lab TAT for GAS NAAT. Although microbiology labs historically use manual processes, the advent of total laboratory automation and the adoption of on-demand NAATs will allow for more streamlined processing of microbiology specimens. It may be beneficial to consider instrument interfacing and specimen processing optimization during the early phases of implementation planning for NAATs in the microbiology laboratory.