Unlike vancomycin trough concentrations, data on the utility of vancomycin pharmacokinetic (PK) parameters, namely, the area under the concentration-time curve from 0 to 24 h (AUC _0–24 ), in predicting acute kidney injury (AKI) are limited. Our aim was to investigate this relationship in patients receiving vancomycin therapy for methicillin-resistant Staphylococcus aureus bacteremia (MRSA-B). A single-center retrospective observational cohort study involving 127 consecutive MRSA-B patients was conducted to examine the incidence of AKI (defined as serum creatinine of ≥0.5 mg/liter and a 50% increase from baseline) and vancomycin exposure parameters associated with nephrotoxicity. Bayesian estimation was used to predict individual vancomycin AUC _0–24 . All patients received vancomycin monotherapy for a minimum of 14 days following the diagnosis of MRSA-B. AKI was observed in 15.7% of patients (20/127). Clinical characteristics were similar between patients with and without AKI. At steady state, higher vancomycin trough concentrations were associated with AKI (17.2 mg/liter versus 13.1 mg/liter; P = 0.003). A vancomycin AUC _0–24 threshold for AKI of >563 mg · h/liter was detected by classification and regression tree (CART) analysis; patients with exposures above this threshold were significantly more likely to experience AKI than patients with lower vancomycin exposures (40% [8/20] versus 11.2% [12/107]; P = 0.002). This parameter remained an independent predictor of AKI on multivariate logistic regression (odds ratio [OR], 5.07; 95% confidence interval [CI], 1.57 to 16.29; P = 0.006) and was a better predictor of nephrotoxicity than vancomycin trough concentrations. Overall, AKI is associated with higher vancomycin exposure as measured by AUC _0–24 . These results suggest that individualized patient dosing may be possible with dose modifications directed toward established pharmacodynamic targets while balancing AKI risks.

Broad-range 16S rRNA PCR can be used for the detection and identification of bacteria from clinical specimens in patients for whom there is a high suspicion of infection and cultures are negative. The aims of this study were (1) to compare 16S rRNA PCR results with microbiological culture results, (2) to assess the utility of 16S rRNA PCR with regard to antimicrobial therapy, and (3) to compare the yield of 16S rRNA PCR for different types of clinical specimen and to perform a cost analysis of the test. A retrospective study was performed on different clinical specimens which had 16S performed over 3 years (2012-2015). Standard microbiological cultures were performed on appropriate media, as per the laboratory protocol. Patient clinical and microbiological data were obtained from the electronic medical records and laboratory information system, respectively. 16S rRNA PCR was performed in a reference laboratory using a validated method for amplification and sequencing. The outcomes assessed were the performance of 16S rRNA PCR, change of antimicrobials (rationalization, cessation, or addition), and duration of therapy. Concordance of 16S rRNA PCR with bacterial cultures was also determined for tissue specimens. Thirty-two patients were included in the study, for whom an equal number of specimens (n=32) were sent for 16S rRNA PCR. 16S rRNA PCR could identify an organism in 10 of 32 cases (31.2%), of which seven were culture-positive and three were culture-negative. The sensitivity was 58% (confidence interval (CI) 28.59-83.5%) and specificity was 85% (CI 61.13-96%), with a positive predictive value of 70% (CI 35.3-91.9%) and negative predictive value of 77.2% (CI 54.17-91.3%). Antimicrobial therapy was rationalized after 16S rRNA PCR results in five patients (15.6%) and was ceased in four based on negative results (12.5%). Overall the 16S rRNA PCR result had an impact on antimicrobial therapy in 28% of patients (9/32). The highest concordance of 16S rRNA PCR with bacterial culture was found for heart valve tissue (80%), followed by joint fluid/tissue (50%). Despite the low diagnostic yield, results of 16S rRNA PCR can still have a significant impact on patient management due to rationalization or cessation of the antimicrobial therapy. The yield of 16S rRNA PCR was highest for heart valves.

Rapidly growing mycobacterial skin and soft tissue infections are known to complicate cosmetic surgical procedures. Treatment consists of more surgery and prolonged antibiotic therapy guided by drug susceptibility testing. Paradoxical reactions occurring during antibiotic therapy can further complicate treatment of non-tuberculous mycobacterial infections. We report a case of post liposuction Mycobacterium abscessus surgical site infection in a returned medical tourist and occurrence of paradox during treatment.

Antimicrobial stewardship (AMS) interventions largely target inpatient antimicrobial prescribing. Literature on appropriateness of antimicrobials prescribed at the interface between hospital and the community is minimal. This study was designed to assess the appropriateness of antimicrobials prescribed on hospital discharge and evaluate the impact of AMS interventions. Patients with discharge medications processed by the pharmacy were identified using a computerized pharmacy medication tracker over a four week period. The antimicrobials prescribed on discharge were assessed independently for appropriateness of antimicrobial choice, dose, frequency and duration. Data on various AMS interventions was collected. Univariate followed by multivariate logistic regression (MVLR) analysis was performed using SPSS V 23 (IBM, California). A total of 892 discharge prescriptions were processed by the pharmacy department, 236 of which contained antibiotic prescriptions. Of these, 74% were appropriate for antimicrobial choice, 64% for dose, 64% for frequency and 21% for duration. In particular, 71% of patients received a course in excess of Therapeutic Guidelines-Australia(TG-A) recommended length of treatment. On univariate analysis, discharge antimicrobial prescriptions were more likely to be appropriate for antimicrobial choice, frequency and duration; appropriate microbiological specimens were more likely to be taken and targeted therapy more likely to be given when the AMS team was involved. On MVLR, appropriateness with antimicrobial dosing frequency [OR 5.6(1.9–19.2)], microbiological specimens [OR 4.3(1.6–11.6)] and receipt of targeted therapy [OR 2.8(1.8–6.2)] with AMS involvement remained significant. A large discrepancy exists between antimicrobial regimens prescribed on hospital discharge and those recommended in consensus guidelines, particularly concerning duration of treatment. While AMS interventions are well established for improving antimicrobial prescribing in hospital inpatients, the hospital-community interface remains a challenge in terms of antimicrobial prescribing and exposes patients to potential harm. There is a clear need for AMS interventions to extend to antimicrobial therapy prescribed on discharge.

Listeria monocytogenes causes gastroenteritis, meningitis and bacteraemia in immunocompromised, pregnant patients, the elderly as well in immunocompetent patients. Focal infections with this organism are uncommon, especially in sporadic (non-outbreak) setting, require high index of suspicion and are challenging to diagnose. We present 3 cases of Listeria monocytogenes presenting as focal infections to our hospitals, all of which are the first reported cases from Australia. Three unrelated cases of unique focal infections caused by Listeria monocytogenes are presented. 1) A 73 year old Caucasian lady on immunosuppression for colorectal cancer presented with prosthetic knee joint septic arthritis, 2) An 83 year old Caucasian man presented with prosthetic vascular graft infection and 3) A 60 year old Asian man with perianal abscess. Except for case 1, the other cases had a prolonged duration of symptoms on presentation. Listeria was not thought to be causative organism in any of these cases until microbiological specimens isolated the organism. Matrix Associated Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) assisted in making an earlier diagnosis of the infection in all three cases. All of these patients had Listeria monocytogenes isolated from clinical specimens. They were managed with antibiotics and surgery with favourable outcomes. Public health investigations to determine any dietary association were done, however no intervention was thought to be necessary in any of the cases except provide dietary advice. The first two cases highlight the importance of microbiological sampling in serious infections for definitive antibiotic therapy to be administered. Sporadic focal infections with Listeria occur infrequently and are often not diagnosed till culture results from microbiological specimens become available. Dietary history should be an important aspect of thorough clinical history and food consumption advice is crucial in immunocompromised patients on similar lines as given to pregnant women about listeriosis.

Background: Bacteraemia is associated with high morbidity and mortality, with delayed antibiotic treatment associated with poorer outcomes. Early identification is challenging, but clinically important. Multiple scoring systems have been developed to identify individuals in the broader categories of sepsis. We designed this study to assess the performance of existing scoring systems and pathways—CEC SEPSIS KILLS pathway (an Australian sepsis care package), quick sequential organ failure score (qSOFA), systemic inflammatory response syndrome (SIRS) and the Shapiro criteria. Methods: This was a retrospective cohort study performed in two metropolitan hospitals in NSW, consisting of adult patients (> 18 years) with positive blood cultures containing a true pathogen and patients matched by age without positive blood cultures. Performance (sensitivity, specificity, and mortality prediction) of recognised sepsis and bacteraemia criteria and pathways—qSOFA, SIRS, Shapiro criteria and CEC SEPSIS KILLS pathway in the first 4 h following ED triage was assessed. Results: There were 251 patients in each cohort. Sepsis-related mortality was higher in the bacteraemic group (OR 0.4, p = 0.03). Of the criteria studied, the modified Shapiro criteria had the highest sensitivity (88%) with modest specificity (37.85%), and qSOFA had the highest specificity (83.67%) with poor sensitivity (19.82%). SIRS had reasonable sensitivity (82.07%), with poor sensitivity (20.72%). The CEC SEPSIS pathway sensitivity of 70.1% and specificity of 71.1%. The SEPSIS KILLS was activated on only 14% of bacteraemic patients. Conclusion: The performance of all scoring systems and pathways was suboptimal in the identification of patients at risk of bacteraemia presenting to the emergency department.