Reducing unnecessary testing on sputum specimens from patients with cystic fibrosis: pathology stewardship in microbiology.

Chronic respiratory tract infection by Pseudomonas aeruginosa is the hallmark of established lung disease in patients with cystic fibrosis (CF). Antibiotic therapy can usually only suppress but not eradicate infection. In recent years, pulmonary infection with non-tuberculous Mycobacteria (NTM) species has also been increasing. These patients are often colonised with multiple isolates and determination of clinical significance of each isolate is difficult. The clinical value of frequent routine susceptibility testing of individual isolates is unproven, particularly since a delay in susceptibility testing is inevitable when purification of multiple cultured isolates is required to test each isolate separately. From August 2019 until December 2020 we ceased routine susceptibility testing on P. aeruginosa respiratory tract isolates from patients with CF if a previous isolate from the patient had susceptibility testing performed. We found that the proportion of P. aeruginosa isolates that had susceptibility testing performed dropped from 97% to 11% as a result of this change in laboratory process. During this time, we also ceased routine culture for acid-fast bacilli if this had been performed within the previous 6 months. We present the cost and resource savings for these changes in laboratory process and assess for clinical impact measured as hospital admissions, length of stay in hospital and mortality.

Identification and characterisation of fosfomycin resistance in Escherichia coli urinary tract infection isolates from Australia.

Of 1033 Escherichia coli urinary tract infection isolates collected from females >12 years of age in Australia in 2019, only 2 isolates were resistant to fosfomycin with a minimum inhibitory concentration (MIC) of >256 mg/L. Despite having different multilocus sequence types, the two isolates harboured an identical plasmid-encoded fosA4 gene. The fosA4 gene has previously been identified in a single clinical E. coli isolate cultured in Japan in 2014. Each fosfomycin-resistant isolate harboured two conjugative plasmids that possessed an array of genes conferring resistance to aminoglycosides, ß-lactams, macrolides, quinolones, sulfonamides and/or trimethoprim.

Surveillance of life-long antibiotics-A cross-sectional cohort study assessing patient attitudes and understanding of long-term antibiotic consumption.

BACKGROUND: Some patients receive long-term or life-long antibiotics for suppression of infections deemed otherwise incurable. Little is known about the consequences of this strategy. We aimed to explore patients' attitudes towards and knowledge concerning prolonged antibiotic therapy. METHODS: A cross-sectional cohort pilot study of outpatients on long-term antibiotics was performed. Surveys were conducted at our healthcare network in Victoria, Australia between April and December 2015. Microbiological screening for multi-resistant organisms (MRO) was also performed. RESULTS: Heterogeneity was noted in the prescribed antibiotics and documented indications, with rifampicin and fusidic acid for suppression of prosthetic joint infection the most common regimen and indication. 41% (12/29) of participants reported side-effects attributed to their antibiotics, but 72% (21/29) still declared complete adherence to their prescribed regimen. 76% (22/29) of participants stated that they would cease their long-term antibiotics based on medical advice. 19/29 (66%) participants consented to microbiological screening and 4 were found to be colonised with MROs. They had spent more days as an inpatient in the preceding 12 months than the screened participants who were not colonised. CONCLUSION: Participants in this study had a good understanding of their infection and the indications for their long-term antibiotic therapy, and were adherent to this therapy despite many experiencing side-effects attributed to their antibiotics. Patients who are prescribed life-long antibiotics can be carriers of multi-resistant organisms, but both the drivers of this resistance, and the broader impact of colonisation with MRO in this population is unclear.

Bacteroides pyogenes causing serious human wound infection from animal bites.

Bacteroides pyogenes is part of the normal oral flora of domestic animals. There is one previous report of human infection, with B. pyogenes bacteremia following a cat bite (Madsen 2011). We report seven severe human infections where B. pyogenes was identified by Bruker matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDTI-TOF MS), but not by VITEK MS and was misidentified by VITEK ANC card.

Improved standardization and potential for shortened time to results with BD Kiestra™ total laboratory automation of early urine cultures: A prospective comparison with manual processing.

We compared the results of 505 urine specimens prospectively processed by both conventional manual processing (MP) with 16-24h incubation to BD Kiestra™ Total Laboratory Automation (TLA) system with a shortened incubation of 14h: 97% of culture results were clinically concordant. TLA processing was associated with improved standardization of time of first culture reading and total incubation time.