Stemming the Rise of Antibiotic Use for Community-Acquired Acute Respiratory Infections during COVID-19 Pandemic

At the start of the COVID-19 pandemic, there was an increase in the use of antibiotics for the treatment of community-acquired respiratory tract infection (CA-ARI) in patients admitted for suspected or confirmed COVID-19, raising concerns for misuse. These antibiotics are not under the usual purview of the antimicrobial stewardship unit (ASU). Serum procalcitonin, a biomarker to distinguish viral from bacterial infections, can be used to guide antibiotic recommendations in suspected lower respiratory tract infection. We modified our stewardship approach, and used a procalcitonin-guided strategy to identify “high yield” interventions for audits in patients admitted with CA-ARI. With this approach, there was an increase in the proportion of patients with antibiotics discontinued within 4 days (16.5% vs. 34.9%, p < 0.001), and the overall duration of antibiotic therapy was significantly shorter [7 (6−8) vs. 6 (3−8) days, p < 0.001]. There was a significant decrease in patients with intravenous-to-oral switch of antibiotics to “complete the course” (45.3% vs. 34.4%, p < 0.05). Of the patients who had antibiotics discontinued, none were restarted on antibiotics within 48 h, and there was no-30-day readmission or 30-day mortality attributed to respiratory infection. This study illustrates the importance of the antimicrobial stewardship during the pandemic and the need for ASU to remain attuned to prescriber’s practices, and adapt accordingly to address antibiotic misuse to curb antimicrobial resistance.

34. Stemming the Rise in Antibiotic Prescription for Community Acquired Respiratory Infections (ARI) During COVID-19 Pandemic in Singapore General Hospital (SGH)

Background

In early months of COVID-19 pandemic, SGH recorded a year-on-year increase in antibiotic (ABx) use for community acquired acute respiratory infection (CA ARI) from Feb-Apr 2019 (48.7 defined daily doses (DDD)/100 bed-days) to 2020 (50.8 DDD/100 bed-days). To address concerns of misuse, the antibiotic stewardship unit (ASU) expanded prospective audit feedback (PAF) to CA ARI patients admitted to ARI wards, with low procalcitonin (PCT). PAF was conducted on day 2-3 of ABx, on weekdays. Doctors received feedback to stop/modify when ABx was deemed inappropriate. Here, we describe the impact of ASU’s adaptive approach to curb rising ABx use in patients admitted for ARI during COVID-19 pandemic.

Methods

A Pre- & Post-intervention study was conducted. All patients started on ABx (ceftriaxone/co-amoxiclav/piptazo/carbapenems/levofloxacin) for CA ARI & PCT &lt; 0.5µg/L were analysed. Those who died ≤48h of admission; admitted to intensive care; required ABx escalation; &gt;1 infective sites; complex lung infection were excluded. Primary objective was to compare the proportion of ABx stopped ≤4 days (time to final infection diagnosis) Pre (22/3-18/4/20) & Post (21/4-13/7/20).

Results

184 (Pre) & 528 (Post) ABx courses were analysed. ASU audited 51 (Pre) & 380 (Post) courses with the rest discontinued/discharged before review. Patients were largely similar in both periods; a third had low likelihood of bacterial infection (C reactive protein &lt; 30mg/L). In Post, 73 feedback was given to stop ABx (often because symptoms suggested viral/fluid overload) & 18 to switch to oral ABx. 82 (90%) feedback was accepted. No ABx was restarted ≤48h or deaths ≤30 days due to ARI. 1 patient had C. difficile diarrhoea a day after ABx cessation as per ASU feedback.

Proportion of all ABx stopped ≤4 days was higher in Post than Pre [27/184 (15%) vs 152/528 (29%), p&lt; 0.01]. Median duration of therapy of IV ABx was reduced (6.5 vs 3 days, p&lt; 0.01), with corresponding shorter median length of stay (10.5 vs 6 days, p&lt; 0.01).

Conclusion

PAF directly and indirectly reduced ABx duration in patients treated for CA ARI as prescribers become more conscious about stopping ABx when investigations show low likelihood of bacterial infection. ASU must remain agile during pandemics to detect emerging problems and adapt processes to counter early.

Disclosures

All Authors: No reported disclosures

Discontinuation of Antibiotics in Patients with Neurological Conditions - A Study on the Impact of an Antimicrobial Stewardship Program (ASP) in a Tertiary Institution

BACKGROUND

Up to 50% of antibiotics are prescribed either unnecessarily or inappropriately in most hospitals worldwide. In the largest tertiary hospital in Singapore, patients with neurological conditions were often initiated on antibiotics for change in mental state or isolated fevers. We hypothesize that Antimicrobial Stewardship Program (ASP) interventions to discontinue empirical antibiotics in neurological patients with no clinical evidence of bacterial infection are safe. The aim of this study was to compare clinical impact and safety outcomes of ASP interventions between accepted and rejected groups.

METHODS

A retrospective review of the ASP database was conducted for all patients admitted to the neurology department in Singapore General Hospital between January 2014 and December 2017. Interventions were followed up and patients were classified into two intervention groups, the accepted and rejected groups. Demographic data, age-adjusted Charlson co-morbidity index, duration of antibiotic therapy, length of hospital stay post-ASP intervention (PLOS), infection-related readmissions and mortality were compared between the two groups. Data were expressed as mean ± standard deviation for continuous variables, and unpaired Student's t-test was performed to determine intergroup differences between mean values.

RESULTS

The ASP team recommended 184 interventions, with an overall acceptance rate of 82.6% (152/184). There was no significant difference in demographics and age-adjusted Charlson co-morbidity index between the two groups. The accepted group had a shorter duration of therapy by 1.67 days (4.99±2.50 days vs. 6.66±2.34 days; P<0.01) and a shorter PLOS by 2 days, although this was not statistically significant (22.5±22.2 days vs. 24.5±51.4 days; P=0.83). There were no significant differences between the two groups in 14-day mortality and readmission rates.

CONCLUSION

In neurological patients with no clinical evidence of bacterial infections, ASP interventions to discontinue empirical antibiotics were not associated with increased mortality and readmissions but were associated with significant reduction in duration of therapy.

1079. Impact of Antimicrobial Stewardship Program (ASP) on Patients with Neurological Conditions

Background

Rising rates of antimicrobial resistance worldwide has dire consequences on patient care, as infections with resistant organisms impair patients’ recovery, resulting in protracted illness and hence prolonged hospital stay. Antimicrobial Stewardship Programs (ASPs) have shown to effectively reduce antibiotic resistance. Locally, we observed that patients with neurological conditions were often initiated on antibiotics for change in mental state or isolated fevers. Little is known whether these patients truly require antibiotics and hence, we aim to study the impact of ASP in these patients.

Methods

Retrospective review of ASP database between January 2014 and December 2017 was conducted, among all patients admitted to the neurology department in SGH and in whom the ASP team recommended discontinuation of empiric use of antibiotics. Demographics were collected. Clinical outcomes, duration of antibiotics therapy, length of hospital stay (LOS), infection-related readmissions and mortality, were compared between interventions accepted and rejected groups.

Results

The ASP team recommended 184 interventions [overall acceptance rate of 82.6% (152/184)]. There was no significant difference in underlying demographics, and Charlson Co-morbidity score between the 2 groups. However, the interventions-acceptance group had shorter duration of therapy by 1.67 days (4.99 ± 2.50 days vs. 6.66 ± 2.34 days; P < 0.01) and LOS by 2 days (22.5 ± 51.4 days vs. 24.5 ± 3.04 days; P = 0.83). There were no significant differences in 14-day mortality and readmission rates between the 2 groups.

Conclusion

In patients with neurological conditions, ASP interventions were safe, and associated with a significant reduction in the duration of therapy and LOS.

Disclosures

All authors: No reported disclosures.

Discontinuation of antibiotic therapy within 24 hours of treatment initiation for patients with no clinical evidence of bacterial infection: a 5-year safety and outcome study from Singapore General Hospital Antimicrobial Stewardship Program

BACKGROUND

Overprescribing antibiotics for patients with no bacterial infection is of growing global concern. It is important for timely Antimicrobial Stewardship Program (ASP) intervention to discontinue antibiotics for patients whose symptoms can be explained by non-infective causes, and without availability of bacterial cultures and susceptibilities reports. This study aimed to evaluate clinical outcomes and safety of early ASP review in these patients.

METHODS

A retrospective review of the ASP database (January 2010 to December 2014) was conducted to identify patients for whom ASP recommended discontinuation of empiric antibiotics within 24 hours of prescribing. Demographics were collected. Clinical outcomes - duration of therapy, length of hospital stay (LOS), infection-related readmissions, and all-cause mortality - were compared between interventions accepted and rejected groups. Continuous data were analysed via unpaired Student's t-test. Categorical data were analysed using χ² test or Fisher's exact test, as appropriate.

RESULTS

The ASP team recommended 794 interventions (overall acceptance rate of 72.9%, 579 of 794). There were no significant between-group differences in underlying demographics, and Charlson comorbidity index score. However, the interventions acceptance group had significantly shorter duration of therapy by 2.61 days (2.72 ± 3.04 vs. 5.33 ± 2.54 days; P < 0.01) and LOS by 7.41 days (7.98 ± 13.14 vs. 15.39 ± 22.62 days; P < 0.01), with estimated cost savings of SGD10 817 per patient. There were no significant between-group differences in 14-day mortality and readmission rates.

CONCLUSION

Prompt ASP interventions at Singapore General Hospital were associated with significant reductions in duration of therapy and LOS, with cost savings. It was demonstrated that it is safe to discontinue antibiotics within 24 hours of prescribing for patients with no evidence of bacterial infections.

Impact of Antimicrobial Stewardship Program (ASP) on Outcomes in Patients with Acute Bacterial Skin and Skin Structure Infections (ABSSSIs) in an Acute-Tertiary Care Hospital

INTRODUCTION

Acute bacterial skin and skin structure infections (ABSSSIs) are among the most common infections treated in hospitals, but to date, there has been little information with regards to the implementation of Antimicrobial Stewardship Programs (ASPs) for patients with ABSSSIs. Hence, we aim to evaluate the impact of ASPs on the following outcomes in patients with ABSSSIs: duration of therapy and hospital stay, 14-day reinfection, infection-related readmissions and mortality.

METHODS

A retrospective review of the ASP database was conducted, focusing on selected outcomes (as above) among all patients in whom the institution's ASP recommended a change in antibiotic regimen-de-escalation of the antibiotic based on culture results; discontinuation of the antibiotic; narrowing of the empirical coverage; and intravenous-to-oral (i.v.-to-p.o.) switch between September 2009 and December 2012. Data were expressed as mean ± standard deviation for continuous variables, and unpaired Student's t test was performed to determine intergroup differences between mean values. For categorical variables, data were presented as number and percentage and analyzed using the χ (2) test or Fisher's exact test, as appropriate.

RESULTS

ASP recommended 407 interventions with an overall acceptance rate of 66.8%. ASP interventions significantly reduced median duration of therapy by 2 [from a median (interquartile range, IQR) of 8 (6-12) days to 6 (4-9) days] and median length of stay by 5 days [from median (IQR) of 12 (5-32) days to 7 (3-18) days]. This led to an estimated total cost avoidance of USD 0.7 million. There were no significant differences in the 14-day reinfection, infection-related readmission and mortality rates between patients whose physicians accepted and those who rejected ASP interventions.

CONCLUSION

Interventions recommended by the ASP in Singapore General Hospital were safe and associated with a significant reduction in duration of therapy and hospital stay. The results of our study have affirmed the role of ASP in optimizing the care of patients with ABSSSI.

Microbiology and audit of vascular access-associated bloodstream infections in multi-ethnic Asian hemodialysis patients in a tertiary hospital

BACKGROUND

In view of high mortality and morbidity rates associated with vascular access-associated bloodstream infection (VAABSI) in hemodialysis patients, clinical practice guidelines recommend empiric antibiotic therapy for suspected vascular access-related infections. We aim to describe the microbiology of confirmed VAABSI and evaluate the choice of empiric antibiotics, and whether they are prescribed in concordance with the in-house antibiotic guidelines.

METHODS

This was a single-center, retrospective, observational study conducted in a tertiary hospital. All adult hemodialysis patients aged 21 years and above who had confirmed VAABSI with positive blood culture results dated from January 2011 to June 2012 were recruited. Relevant information was retrieved electronically from the hospital patient online database, SCM 5.5 Sunrise Enterprise Gateway.

RESULTS

A total of 144 episodes of VAABSI were recorded from 118 patients. Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) accounted for 64.2% (68/106) of the gram-positive infections. Gram-negative organisms grew in 26.4% (38/144) of blood cultures and Pseudomonas aeruginosa was the most common organism isolated. The recommended in-house guideline was used as empiric therapy in 24 episodes of VAABSI (16.7%). Five patients died due to VAABSI and none were prescribed antibiotics in concordance with in-house guidelines.

CONCLUSIONS

Empiric antibiotics against MSSA and MRSA, as well as gram-negative organisms, especially P. aeruginosa, should be used in patients with suspected vascular access-related infections in our institution. Monitoring of microbiological profile is necessary to guide timely administration of appropriate empiric antibiotics. Further studies are necessary to evaluate the relationship between adherence to in-house guidelines and patients' outcomes.

Case reports of nocardiosis in patients with human immunodeficiency virus (HIV) infection

INTRODUCTION

We present 4 local cases of nocardiosis in HIV-infected patients and discuss the diagnosis, clinical syndromes and therapy of nocardiosis.

CLINICAL PICTURE

Two cases presented with pulmonary nocardiosis, one had a cervical lymph node abscess and one had disseminated nocardiosis with pulmonary, cerebral and soft tissue involvement.

TREATMENT

Combination therapy is often employed. Sulphonamides or co-trimoxazole, amikacin, imipenen, minocycline and ceftriaxone are some of the drugs that could be used.

OUTCOME

Outcome hinges on the early recognition and optimal treatment of this infection.

CONCLUSIONS

Clinical presentations vary and diagnosis is difficult and frequently delayed. Nocardiosis should be suspected in patients who present with pulmonary lesions with soft tissue and/or cerebral abscesses.

In vivo association of pp60v-src and the gap-junction protein connexin 43 in v-src-transformed fibroblasts

v-src-transformed fibroblasts have significantly reduced levels of gap junction-mediated intercellular communication. This observed downregulation of cellular communication has been associated with tyrosine phosphorylation of the gap-junction protein connexin 43 (Cx43). Previously, we demonstrated that purified, kinase-active pp60src phosphorylates Cx43 in vitro (J Biol Chem 1995; 270:12751-12761). More recently, we reported that this association is mediated by the SH2 and SH3 domains of pp60v-src (J Biol Chem 1997;272:22824-22831). In this report, we present in vivo evidence supporting the hypothesis that Cx43 is an endogenous substrate of pp60v-src in v-src-transformed fibroblasts. Cytological localization studies with confocal microscopy demonstrated that pp60v-src and Cx43 were partially co-localized in regions of the plasma membrane. Cx43 and pp60v-src co-immunoprecipitated from v-src-transformed fibroblasts, indicating that the two proteins were associated, and form a stable complex. Furthermore, pp60v-src could phosphorylate co-immunoprecipitated Cx43 in an immune-complex kinase assay. Two-dimensional phosphopeptide mapping of the immune-complexed Cx43 phosphorylated in vitro demonstrated that the sites of tyrosine phosphorylation were consistent with previously identified sites of pp60v-src phosphorylation. These results provide additional in vivo evidence that Cx43 is a direct substrate of pp60v-src in v-src-transformed fibroblasts. The ability of pp60v-src to alter gap junction-mediated cellular communication may serve as one mechanism by which pp60v-src initiates and/or maintains aspects of cellular transformation.

Tyrosine phosphorylation of connexin 43 by v-Src is mediated by SH2 and SH3 domain interactions

Reduction of gap junctional communication in v-src transformed cells is accompanied by tyrosine phosphorylation of the gap junction protein, connexin 43 (Cx43). Cx43 is phosphorylated on tyrosine by v-Src. The Src homology 3 (SH3) and Src homology 2 (SH2) domains of v-Src mediate interactions with substrate proteins. SH3 domains interact with proline-rich peptide motifs. SH2 domains associate with short amino acid sequences containing phosphotyrosine. We present evidence that the SH3 and SH2 domains of v-Src bind to proline-rich motifs and a phosphorylated tyrosine residue in the C-terminal tail of Cx43. Cx43 bound to the SH3 domain of v-Src, but not c-Src, in vitro. Tyrosine-phosphorylated Cx43 bound to the SH2 domain of v-Src in vitro. v-Src coprecipitated with Cx43 from v-src-transformed Rat-1 fibroblasts. Mutations in the SH3 and SH2 domains of v-Src, and in the proline-rich region or tyrosine 265 of Cx43, reduced interactions between v-Src and Cx43 in vivo. Tyrosine phosphorylation of Cx43 was dependent on the association of v-Src and Cx43. These results provide further evidence for the direct involvement of v-Src in tyrosine phosphorylation of Cx43 and inhibition of gap junctional communication in v-src-transformed cells.

Regulation of connexin43 function by activated tyrosine protein kinases

Gap junctions are specialized membrane structures that are involved in the normal functioning of numerous mammalian tissues and implicated in several human disease processes. This mini-review focuses on the regulation of gap junctions through phosphorylation of connexin43 induced by the v-Src or epidermal growth factor receptor tyrosine kinases. These tyrosine kinases markedly disrupt gap junctional communication in mammalian cells. here, we describe work correlating the alteration of connexin43 function with the ability of the v-Src tyrosine kinase to phosphorylate connexin43 directly on two distinct tyrosine sites in mammalian cells (Y247 and Y265). We also present evidence that proline-rich regions and phosphotyrosine sites of connexin43 may mediate interactions with the SH3 and SH2 domains of v-Src. In contrast to v-Src, the activated epidermal growth factor receptor acts indirectly through activated MAP kinase which may stimulate phosphorylation of connexin43 exclusively on serine. This phosphorylation event is complex because MAP kinase phosphorylates three serine sites in connexin43 (S255, S279, and S282). These findings suggest novel interactions between connexin43, the v-Src tyrosine kinase, and activated MAP kinase that set the stage for future investigations into the regulation of gap junctions by protein phosphorylation.

Characterization of the mitogen-activated protein kinase phosphorylation sites on the connexin-43 gap junction protein

We have previously demonstrated that epidermal growth factor induced a rapid, transient decrease in gap junctional communication and increase in serine phosphorylation on the connexin-43 gap junction protein in T51B rat liver epithelial cells. The kinase(s) responsible for phosphorylation and specific serine targets in connexin-43 have not been identified. There are three consensus mitogen-activated protein (MAP) kinase serine phosphorylation sequences in the carboxyl-terminal tail of connexin-43 and purified MAP kinase phosphorylated connexin-43 in vitro on tryptic peptides that comigrated with a subset of peptides from connexin-43 phosphorylated in vivo in cells treated with epidermal growth factor. These data suggested that MAP kinase may phosphorylate connexin-43 directly in vivo. We have utilized a glutathione S-transferase fusion protein containing the cytoplasmic tail of connexin-43 to characterize MAP kinase phosphorylation. Site-directed mutagenesis, phosphotryptic peptide analysis, and peptide sequencing have confirmed that MAP kinase can phosphorylate connexin-43 at Ser255, Ser279, and Ser282, which correspond to the consensus sites recognized earlier. Characterization of MAP kinase-mediated phosphorylation of connexin-43 has defined potential targets for phosphorylation in vivo following activation of the epidermal growth factor receptor and has provided the basis for studies of the effects of phosphorylation, at specific molecular sites, on the regulation of gap junctional communication.

pp60src-mediated phosphorylation of connexin 43, a gap junction protein

Several laboratories have demonstrated a decrease in gap junctional communication in cells transformed by the src oncogene of the Rous sarcoma virus. The decrease in gap junctional communication was associated with tyrosine phosphorylation of the gap junction protein, connexin 43 (Cx43). This study was initiated to determine if the phosphorylation of Cx43 is the result of a direct kinase-substrate interaction between the highly active tyrosine kinase, pp60v-src, and Cx43. Previous biochemical studies have been limited by the low levels of Cx43 protein in fibroblast cell lines. To obtain larger quantities of Cx43, we constructed a recombinant baculovirus expressing Cx43 in Spodoptera frugiperda (Sf-9) cells and subsequently purified the expressed Cx43 by immunoaffinity chromatography. We observed that this partially purified Cx43 was phosphorylated on tyrosine in vitro in the presence of kinase-active pp60src. Phosphotryptic peptide mapping indicated that the in vitro phosphorylated Cx43 contained phosphopeptides which comigrated with a subset of tryptic peptides prepared from Cx43 phosphorylated in vivo. Furthermore, coinfection of Sf-9 cells with recombinant baculoviruses encoding pp60v-src and Cx43 resulted in the accumulation of phosphotyrosine in Cx43. Taken together, the evidence presented in this paper demonstrates that kinase active pp60c-src is capable of phosphorylating Cx43 in a direct manner. Since the presence of phosphotyrosine on Cx43 is correlated with the down-regulation of gap-junctional communication, these results suggest that pp60v-src regulates gap junctional gating activity via tyrosine phosphorylation of Cx43.