Search

Background: Nocardia is a ubiquitous saprophyte capable of causing human disease. Disease is primarily respiratory or cutaneous, usually acquired via inhalation or inoculation. Under the influence of environmental and host factors, Nocardia incidence and species distribution demonstrate geographical variation., Aims: To examine for differences in Nocardia incidence within Western Australia (WA) and analyse species distribution in the context of prior published studies. To analyse antibiogram data from a nationwide passive antimicrobial resistance surveillance program., Methods: Retrospective extraction of laboratory data for Western Australian Nocardia isolates over a 21-year period. Analysis of Nocardia antimicrobial susceptibility testing data submitted to the Australian Passive Antimicrobial Resistance Surveillance (APAS) program between 2005 and 2022., Results: Nine hundred sixty WA isolates were identified, giving an annual incidence of 3.03 per 100 000 population with apparent latitudinal variation. The four most common species identified within WA and amongst APAS isolates were N. nova, N. cyriacigeorgica, N. brasiliensis and N. farcinica. APAS data demonstrated that all species exhibited high rates of susceptibility to linezolid (100%) and trimethoprim-sulfamethoxazole (98%). Amikacin (>90% susceptibility for all species except N. transvalensis) was the next most active parenteral agent, superior to both carbapenems and third-generation cephalosporins. Susceptibility to oral antimicrobials (other than linezolid) demonstrated significant interspecies variation., Conclusions: We demonstrate geographical variation in the distribution of Nocardia incidence. Four species predominate in the Australian setting, and nationwide data confirm a high in vitro susceptibility to trimethoprim-sulphamethoxazole and linezolid, justifying their ongoing role as part of first-line empiric therapy., (© 2023 Royal Australasian College of Physicians.)

Background: Antifungal administration via outpatient parenteral antimicrobial therapy (OPAT) is infrequent. As patients with invasive fungal infections (IFIs) receiving OPAT are at high risk of readmissions, careful, risk-based patient selection and monitoring is important., Objectives: To describe our experience managing IFIs via OPAT, including assessment of risk factors associated with unplanned readmissions., Patients and Methods: A retrospective cohort study of outpatients from two tertiary hospitals in Western Australia managed with parenteral antifungals for the treatment of IFIs from 2012 to 2020. Outcomes assessed were unplanned OPAT-related readmissions; adverse events and achievement of treatment aim at the completion of OPAT., Results: Forty-six patients were included, encompassing 696 OPAT days. Twenty-three (50%) patients received intravenous (IV) liposomal amphotericin B (L-AmB), 23 (50%) received IV echinocandins and one (2%) patient received IV fluconazole. One patient received both IV L-AmB and an echinocandin. Unplanned OPAT-related readmissions occurred in 13 (28%) patients and any adverse event occurred in 19 (41%), most commonly nephrotoxicity amongst patients receiving L-AmB. On univariate analysis, unplanned OPAT-related readmissions were more common in Mucorales infection, L-AmB doses of ≥5 mg/kg and otorhinolaryngologic (ENT) infections. At the completion of OPAT, attainment of treatment aims occurred in 28 (61%) patients., Conclusions: Patients receiving parenteral antifungals via OPAT experience high rates of unplanned readmissions and adverse events. Risk factor identification may facilitate optimal patient selection and establishment of treatment aims., (© 2022 Wiley-VCH GmbH.)

Background: Outpatient parenteral antimicrobial therapy (OPAT) delivery using peripherally inserted central catheters is associated with a risk of catheter related thrombosis (CRT). Individualised preventative interventions may reduce this occurrence, however patient selection is hampered by a lack of understanding of risk factors. We aimed to identify patient, infection or treatment related risk factors for CRT in the OPAT setting., Methods: Retrospective case control study (1:3 matching) within OPAT services at two tertiary hospitals within Australia., Results: Over a 2 year period, encompassing OPAT delivery to 1803 patients, there were 19 cases of CRT, giving a prevalence of 1.1% and incidence of 0.58/1000 catheter days. Amongst the cases of CRT, there were nine (47%) unplanned readmissions and two (11%) pulmonary emboli. Compared to controls, cases had a higher frequency of malposition of the catheter tip (4/19 (21%) vs 0/57 (0%), p  = 0.003) and complicated catheter insertion (3/19 (16%) vs 1/57 (2%), p  = 0.046)., Conclusions: Although CRTs during OPAT are infrequent, they often have clinically significant sequelae. Identification of modifiable vascular access related predictors of CRT should assist with patient risk stratification and guide risk reduction strategies.

Background: Although common, antimicrobial allergy labels (AAL) rarely reflect immunologically-mediated hypersensitivity and can lead to poorer outcomes from alternative antimicrobial agents. Antimicrobial stewardship programs are ideally placed to assess AAL early as a means of improving antimicrobial use., Aims: To quantify the prevalence of AAL in patients referred for antimicrobial stewardship review and assess their impact on antibiotic prescribing, patient mortality, hospital length of stay, readmission and rates of multidrug-resistant infections., Methods: We conducted a retrospective analysis of adult patients referred for inpatient antimicrobial prospective audit and feedback rounds (PAFR) through an electronic referral system (eReferrals) over a 12-month period in 2015. Outcome data were collected for a period of 36 months following the initial review., Results: Of the 639 patient records reviewed, 630 met inclusion criteria; 103 (16%) had an AAL, of which 82 (13%) had reported allergies to β-lactam antibiotics. Those with AAL were significantly less likely to be receiving guideline-recommended antimicrobial therapy (50% vs 64%, P = 0.0311); however, there were no significant difference in mortality, hospital length of stay, readmission or increased incidence of multidrug-resistant infections., Conclusions: Our cohort demonstrated that AAL was associated with reduced adherence to antibiotic guidelines. The lack of association with adverse outcomes may reflect limitations within the study including retrospective cohort study numbers and observational nature, further skewed by high rates of poor documentation. A clear opportunity exists for antimicrobial stewardship programs to incorporate allergy assessment, de-labelling, challenge and referral into these rounds., (© 2020 Royal Australasian College of Physicians.)

Subcutaneous (SC) administration of ertapenem in outpatient parenteral antimicrobial therapy (OPAT) services may be a practical alternative to intravenous delivery for complicated infections. The clinical features and outcomes according to route of administration were compared from a large Australian OPAT service. Chronic renal impairment was more common in the SC group, reflecting an opportunity for route of administration as a vein preservation strategy. Adverse events were uncommon and successful outcomes were not different between the groups., (© 2021 Royal Australasian College of Physicians.)

Objectives: Concerns regarding the clinical impact of meropenem instability in continuous infusion (CI) devices may contribute to inconsistent uptake of this method of administration across outpatient parenteral antimicrobial therapy (OPAT) services., Methods: We retrospectively reviewed the clinical efficacy and safety of CIs of meropenem in two Australian tertiary hospitals and assessed its stability under simulated OPAT conditions including in elastomeric infusion devices containing 1% (2.4 g) or 2% (4.8 g) concentrations at either 'room temperature' or 'cooled' conditions. Infusate aliquots were assayed at different time-points over 24 hours., Results: Forty-one (82%) of 50 patients had clinical improvement or were cured. Adverse patient outcomes including hemato-, hepato- and nephrotoxicity were infrequent. Cooled infusers with 1% meropenem had a mean 24-hour recovery of 90.3%. Recoveries of 1% and 2% meropenem at room temperature and 2% under cooled conditions were 88%, 83% and 87%, respectively. Patients receiving 1% meropenem are likely to receive >95% of the maximum deliverable dose (MDD) over a 24-hour period whilst patients receiving 2% meropenem should receive 93% and 87% of the MDD under cooled and room temperature conditions, respectively., Conclusions: Meropenem infusers are likely to deliver ∼95% MDD and maintain effective plasma concentrations throughout the dosing period. These data reflect our local favourable clinical experience with meropenem CIs.

Alternative oxidase (AOX) is a mitochondrial protein that acts as an alternative terminal oxidase to the conventional cytochrome oxidases. It is present in certain prokaryotes, plants, fungi and some protozoa but absent in mammals. AOX activity has previously been described in Acanthamoeba, although no genetic evidence has been reported. Herein, two AOX (AcAOX) genes designated isoforms A and B, were obtained from Acanthamoeba castellanii by a combination of degenerate PCR from cDNA and a series of 5' and 3' rapid amplification of cDNA ends. The corresponding genomic sequences of these AcAOXs were also obtained. Each gene spans six exons over a region of 1607 and 1619bp, respectively. Isoforms A and B have open reading frames of 1113 and 1125bp, respectively. Each encodes a protein with a predicted molecular weight of 42kDa. Each AcAOX protein has a predicted cleavable mitochondrial targeting sequence. The full-length AcAOX is functionally active as it complements hemL-deficient Escherichia coli and inhibited by the inhibitor of AOX, salicylhydroxamic acid (SHAM). SHAM is effective against A. castellanii and Acanthamoeba polyphaga only when used in conjunction with antimycin A, an inhibitor of the conventional cytochrome respiratory pathway. Transcripts for AcAOX are increased during the encystment process, indicating a possible role for alternative respiration during stress.

Among 125 inpatients with diabetic foot infections managed by a multidisciplinary foot ulcer unit, knowledge of methicillin‐resistant Staphylococcus aureus colonisation status assisted decision‐making to prescribe appropriately or with‐hold empiric anti‐methicillin‐resistant Staphylococcus aureus therapy. Despite adherence to national guidelines, apparent overuse of anti‐pseudomonal therapy was frequent, providing potential antimicrobial stewardship opportunities. [ABSTRACT FROM AUTHOR]

Objectives: Most outpatient parenteral antimicrobial therapy (OPAT) services use a hospital-based model of care in which patients remain in proximity to large hospitals facilitating clinical review. We aimed to evaluate clinical outcomes and complication rates for patients living in geographically isolated locations managed by telemedicine-supported OPAT. Methods: This was a retrospective cohort study.Results: Between 2011 and 2015, we delivered 88 episodes of care involving 83 adult patients resulting in 2261 days of OPAT. The median age was 56 years, 8 of 83 (10%) were indigenous Australian and the median Charlson comorbidity index score was 2 (IQR 1-4). The median distance of patients' residence from our hospital was 288 km (IQR 201-715) and the median duration on the programme was 26 days (IQR 14-34). Bone and joint infections accounted for 75% of infections treated. Favourable clinical outcomes (improvement or cure) were achieved in 87% of patients and the unplanned, OPAT-related readmission rate was 8%. Nineteen percent and 10% of patients had drug-related and line-related adverse effects, respectively.Conclusions: Despite a complex case mix, our adverse event and readmission rates are similar to the published literature describing a non-telemedicine model to deliver OPAT. High rates of favourable clinical outcomes and likely cost benefits suggest that telemedicine-supported OPAT is an efficacious and safe substitute for inpatient care in our setting. [ABSTRACT FROM AUTHOR]

Abstract: Intravenous (i.v.) vancomycin is increasingly used as outpatient parenteral antimicrobial therapy (OPAT). Despite the potential advantages of administration by continuous infusion (CI) compared with intermittent infusion (II), the relative nephrotoxicity of these two modes of delivery has not been well established. We compared the rate of nephrotoxicity of vancomycin given by CI and II. A retrospective cohort study of OPAT patients receiving i.v. vancomycin between January 2004 to June 2008 was performed. All patients had a normal baseline serum creatinine concentration. Propensity scoring analysis was used to adjust for risk factors of CI. The primary outcomes examined were the prevalence and rate of onset of nephrotoxicity. A total of 167 patients receiving vancomycin were identified, 112 by CI and 55 by II. The overall cumulative prevalence of nephrotoxicity was 15.6%. There were significant differences in baseline characteristics between the two groups. Matching based on propensity scores was undertaken, leaving 80 patients available for the analysis. Both in unadjusted and adjusted analyses, vancomycin CI was associated with a slower onset of nephrotoxicity but not a lower prevalence of nephrotoxicity. Both groups received a similar cumulative vancomycin dose. In adult OPAT patients with normal renal function, vancomycin CI was associated with a slower onset of nephrotoxicity. [Copyright &y& Elsevier]

Background: Diabetic foot infections (DFI) present a major morbidity, mortality and economic challenge for the tertiary health sector. However, lack of high quality evidence for specific treatment regimens for patients with DFIs may result in inconsistent management. This study aimed to identify DFI caseload proportion and patterns of clinical practice of Infectious Diseases (ID) Physicians and Trainees within Australia and New Zealand. Methods: A cross-sectional online survey of Australian and New Zealand ID Physicians and Trainees was undertaken, to estimate the overall ID caseload devoted to patients with DFIs and assess clinicians’ management practices of patients with DFIs. Results: Approximately 28% (142/499) of ID Physicians and Trainees from Australia and New Zealand responded to the survey. DFI made up 19.2% of all ID consultations. Involvement in multidisciplinary teams (MDT) was common as 77.5% (93/120) of those responding indicated their patients had access to an inpatient or outpatient MDT. Significant heterogeneity of antimicrobial treatments was reported, with 82 unique treatment regimens used by 102 respondents in one scenario and 76 unique treatment regimens used by 101 respondents in the second scenario. The duration of therapy and the choice of antibiotics for microorganisms isolated from superficial swabs also varied widely. Conclusions: Patients with DFIs represent a significant proportion of an ID clinician’s caseload. This should be reflected in the ID training program. Large heterogeneity in practice between clinicians reflects a lack of evidence from well-designed clinical trials for patients with DFI and highlights the need for management guidelines informed by future trials. [ABSTRACT FROM AUTHOR]