Vancomycin ototoxicity and nephrotoxicity. A review

Recent Trends in Therapeutic Drug Monitoring of Peptide Antibiotics

Antimicrobial peptides take a specific position in the field of antibiotics (ATBs), however, from a large number of available molecules only a few of them were approved and are used in clinics. These therapeutic modalities play a crucial role in the management of diseases caused by multidrug-resistant bacterial pathogens and represent the last-line therapy for bacterial infections. Therefore, there is a demand for a rationale use of such ATBs based on optimization of the dosing strategy to minimize the risk of resistance and ensure the sustainable efficacy of the drug in real clinical practice. Therapeutic drug monitoring, as a measurement of drug concentration in the body fluids or tissues, results in the optimization of the patient´s medication and therapy outcome. This strategy is beneficial and could result in tailored therapy for different types of infection and the prolongation of the use and efficacy of ATBs in hospitals. This review paper provides an actual overview of approved antimicrobial peptides used in clinical practice and covers current trends in their analysis by convenient and advanced methodologies used for their identification and/or quantitation in biological matrices for therapeutic drug monitoring purposes. Special emphasis is given to the methods with perspective clinical outcomes.

Vancomycin Hydrochloride as a Risk Factor for Acute Kidney Injury: A Retrospective Study

INTRODUCTION

The incidence of acute kidney injury (AKI) caused by vancomycin hydrochloride (VCM) was reported to be 5-43%. VCM-induced AKI was reported to be more likely to occur 4-17 days after initiating VCM treatment; however, it may occur earlier. The aim of this study was therefore to investigate risk factors for the development of AKI within two (AKI2days) and seven (AKI7days) days of VCM administration.

METHODS

This was a single-center, retrospective study including patients who underwent VCM therapy between April 1, 2013, and December 31, 2019. AKI was evaluated based on the Kidney Disease: Improving Global Outcomes criteria.

RESULTS

In total, 287 patients were enrolled. The incidence of VCM-induced AKI within 7 days was 10.8% (31/286 cases), and the incidence of AKI within 2 days was 5.9% (15/252 cases). Serum VCM trough concentrations and tazobactam-piperacillin (TZP) were shown to be a risk factor for VCM-induced AKI. The serum VCM trough concentration was 12.67 μg/mL within the 48 h threshold (AKI2days) and 19.03 μg/mL within the 7-day threshold (AKI7days).

CONCLUSION

Our study demonstrated that high serum VCM trough concentrations and the combination of VCM and TZP were independent risk factors for VCM-induced AKI. Avoiding the concomitant use of TZP, or thorough monitoring of renal function with the concomitant use of TZP, may be helpful in reducing the occurrence of AKI. Furthermore, monitoring serum VCM trough concentrations within 2 days may effectively reduce the incidence of AKI.

Comparative Risk of Acute Kidney Injury Following Concurrent Administration of Vancomycin with Piperacillin/Tazobactam or Meropenem: A Systematic Review and Meta-Analysis of Observational Studies

The study aims to comparatively assess the nephrotoxicity of vancomycin when combined with piperacillin-tazobactam (V + PT) or meropenem (V + M) in adult patients hospitalized in general wards or intensive care units. We searched MEDLINE, Google Scholar, and Web of Science for observational studies evaluating incidences of AKI in adult patients receiving V + PT or V + M for at least 48 h in general wards or intensive care units. The primary outcome was AKI events, while the secondary outcomes were hospital length of stay, need for renal replacement therapy (RRT), and mortality events. The odds ratio (OR), or mean difference for the hospital length of stay, with a corresponding 95% confidence interval (CI) from the inverse variance weighting random-effects model were estimated for the risk of AKI, RRT, and mortality. Of the 112 studies identified, twelve observational studies were included in this meta-analysis with a total of 14,511 patients. The odds of having AKI were significantly higher in patients receiving V + PT compared with V + M (OR = 2.31; 95%CI 1.69–3.15). There were no differences between V + PT and V + M in the hospital length of stay, RRT, or mortality outcomes. Thus, clinicians should be vigilant while using V + PT, especially in patients who are at high risk of AKI.

Aminoglycoside- and glycopeptide-induced ototoxicity in children: a systematic review

Background

Ototoxicity has been reported after administration of aminoglycosides and glycopeptides.

Objectives

To identify available evidence for the occurrence and determinants of aminoglycoside- and glycopeptide-related ototoxicity in children.

Materials and methods

Systematic electronic literature searches that combined ototoxicity (hearing loss, tinnitus and/or vertigo) with intravenous aminoglycoside and/or glycopeptide administration in children were performed in PubMed, EMBASE and Cochrane Library databases. Studies with sample sizes of ≥50 children were included. The QUIPS tool and Cochrane criteria were used to assess the quality and risk of bias of included studies.

Results

Twenty-nine aminoglycoside-ototoxicity studies met the selection criteria (including 7 randomized controlled trials). Overall study quality was medium/low. The frequency of hearing loss within these studies ranged from 0%–57%, whereas the frequency of tinnitus and vertigo ranged between 0%–53% and 0%–79%, respectively. Two studies met the criteria on glycopeptide-induced ototoxicity and reported hearing loss frequencies of 54% and 55%. Hearing loss frequencies were higher in gentamicin-treated children compared to those treated with other aminoglycosides. In available studies aminoglycosides had most often been administered concomitantly with platinum agents, diuretics and other co-medication.

Conclusions

In children the reported occurrence of aminoglycoside/glycopeptide ototoxicity highly varies and seems to depend on the diagnosis, aminoglycoside subtype and use of co-administered medication. More research is needed to investigate the prevalence and determinants of aminoglycoside/glycopeptide ototoxicity. Our results indicate that age-dependent audiological examination may be considered for children frequently treated with aminoglycosides/glycopeptides especially if combined with other ototoxic medication.

Risk Factors for Development of Acute Kidney Injury in COVID-19 Patients: A Retrospective Observational Cohort Study

INTRODUCTION

Acute kidney injury (AKI) in coronavirus infection disease (COVID-19) is associated with disease severity. We aimed to evaluate risk factors associated with AKI beyond COVID-19 severity.

METHODS

A retrospective observational study of COVID-19 patients admitted to a tertiary hospital in Singapore. Logistic regression was used to evaluate associations between risk factors and AKI (based on Kidney Disease Improving Global Outcomes criteria). Dominance analysis was performed to evaluate the relative importance of individual factors.

RESULTS

Seven hundred seven patients were included. Median age was 46 years (interquartile range [IQR]: 29-57) and 57% were male with few comorbidities (93%, Charlson Comorbidity Index [CCI] <1). AKI occurred in 57 patients (8.1%); 39 were in AKI stage 1 (68%), 9 in stage 2 (16%), and 9 in stage 3 (16%). Older age (adjusted odds ratio [aOR] 1.04; 95% confidence interval [CI]: 1.01-1.07), baseline use of angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) (aOR 2.86; 95% CI: 1.20-6.83), exposure to vancomycin (aOR 5.84; 95% CI: 2.10-16.19), use of nonsteroidal anti-inflammatory drugs (NSAIDs) (aOR 3.04; 95% CI: 1.15-8.05), and severe COVID-19 with hypoxia (aOR 13.94; 95% CI: 6.07-31.98) were associated with AKI in the multivariable logistic regression model. The 3 highest ranked predictors were severe COVID-19 with hypoxia, vancomycin exposure, and age, accounting for 79.6% of the predicted variance (41.6, 23.1, and 14.9%, respectively) on dominance analysis.

CONCLUSION

Severe COVID-19 is independently associated with increased risk of AKI beyond premorbid conditions and age. Appropriate avoidance of vancomycin and NSAIDs are potentially modifiable means to prevent AKI in patients with COVID-19.

Ototoxicity of Non-aminoglycoside Antibiotics

It is well-known that aminoglycoside antibiotics can cause significant hearing loss and vestibular deficits that have been described in animal studies and in clinical reports. The purpose of this review is to summarize relevant preclinical and clinical publications that discuss the ototoxicity of non-aminoglycoside antibiotics. The major classes of antibiotics other than aminoglycosides that have been associated with hearing loss in animal studies and in patients are discussed in this report. These antibiotics include: capreomycin, a polypeptide antibiotic that has been used to treat patients with drug-resistant tuberculosis, particularly in developing nations; the macrolides, including erythromycin, azithromycin and clarithromycin; and vancomycin. These antibiotics have been associated with ototoxicity, particularly in neonates. It is critical to be aware of the ototoxic potential of these antibiotics since so much attention has been given to the ototoxicity of aminoglycoside antibiotics in the literature.

Toxicity Profile and Pharmacokinetic Study of Antibiotic Mixtures, Gentamicin and Vancomycin, in Rat Plasma by Ecofriendly Liquid Chromatography Coupled Tandem Mass Spectrometry

The global burden of bacterial infection and antimicrobial resistance increases the demand to associate more than one antibiotic to fight life-threatening bacteria. Therefore, there is a great necessity to develop simple and sensitive methods for routine analysis of clinical samples. Therapeutic drug monitoring, bioequivalence, and pharmacokinetic studies are essential to ensure drug efficiency and safety. Herein, therefore, the first ecofriendly liquid chromatography -tandem mass spectrometry (LC-MS/MS) method was developed and fully validated for simultaneous determination of a commonly combined antibiotic for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin (VCM) and gentamicin (GTM), in rat plasma after parenteral administration. VCM and GTM were extracted from plasma sample using acetonitrile (ACN)/0.1% TFA-induced protein precipitation followed by the separation on an Agilent Eclipse Plus ODS (3 mm × 100 mm, 3.5 μm) column using water-enriched mobile phase consisting of water containing 0.1% THF/ACN (85:15, v/v%) at flow rates of 0.30 mL min^-1. The mass spectrometry parameters were optimized, and multiple reaction monitoring (MRM) in positive ion mode of two transitions was utilized for quantification of precursor to product ion at m/z 725.5 → 144 and 100.1 for VCM as [M + 2H]²⁺, 478.3 → 322.2 and 156.9 for GTM, and 586.3 → 162.9 and 425.3 for amikacin (AMK) internal standard, as [M + H]⁺. The current method has been validated as per U.S. FDA bioanalytical guidelines in terms of linearity, accuracy, precision, selectivity, recovery, matrix effects, and stability. The method was linear in the range of 1-2000 ng mL^-1 and 1-1000 ng mL^-1 with detection limits (S/N of 3) of 0.18 and 0.09 ng mL^-1 for VCM and GTM, respectively. The selectivity and high sensitivity allow the current method to succeed in the study of pharmacokinetic parameters and drug-drug interaction between VCM and GTM after single-dose administration. VCM increased plasma clearance and elimination rate constant of GTM when coadministered and GTM also too. The change of serum chemistry analysis and significant elevation of creatinine and BUN indicate an alteration in kidney function in group III in those given the combined antibiotics. Our finding illustrated the nephrotoxicity of the two drugs when associated. The ecofriendly, simplicity, and rapidity of the current study made it a promising method for high-throughput biomonitoring in clinical samples.

Vancomycin-Induced Kidney Injury: Animal Models of Toxicodynamics, Mechanisms of Injury, Human Translation, and Potential Strategies for Prevention

Vancomycin is a recommended therapy in multiple national guidelines. Despite the common use, there is a poor understanding of the mechanistic drivers and potential modifiers of vancomycin-mediated kidney injury. In this review, historic and contemporary rates of vancomycin-induced kidney injury (VIKI) are described, and toxicodynamic models and mechanisms of toxicity from preclinical studies are reviewed. Aside from known clinical covariates that worsen VIKI, preclinical models have demonstrated that various factors impact VIKI, including dose, route of administration, and thresholds for pharmacokinetic parameters. The degree of acute kidney injury (AKI) is greatest with the intravenous route and higher doses that produce larger maximal concentrations and areas under the concentration curve. Troughs (i.e., minimum concentrations) have less of an impact. Mechanistically, preclinical studies have identified that VIKI is a result of drug accumulation in proximal tubule cells, which triggers cellular oxidative stress and apoptosis. Yet, there are several gaps in the knowledge that may represent viable targets to make vancomycin therapy less toxic. Potential strategies include prolonging infusions and lowering maximal concentrations, administration of antioxidants, administering agents that decrease cellular accumulation, and reformulating vancomycin to alter the renal clearance mechanism. Based on preclinical models and mechanisms of toxicity, we propose potential strategies to lessen VIKI.

Drug-induced hearing loss: a case/non-case study in the French pharmacovigilance database

Hearing loss is defined as a decrease in the ability to perceive sounds which can occur suddenly or gradually and affects one ear or both. It is related to various etiologies, in particular drugs. The identification of all drugs that could be associated with hearing loss is essential for the patients' life quality. The objective of our study was to identify signals of hearing loss involving drugs approved in the last 20 years. The occurrence in association with drugs known for their ototoxicity was also analyzed. We used a case/non-case method in the French Pharmacovigilance Database (FPVD). The cases were reports of hearing loss in the FPVD between January 2007 and August 2017. Non-cases were all reports over the same period. We calculated the reporting odds ratio (ROR) with 95% confidence intervals. Among the 555 reports of hearing loss, significant RORs were found for 68 drugs. The main therapeutic classes implicated were antineoplastic agents (n = 240), systemic anti-infective agents (n = 182), immunosuppressants (n = 42) loop diuretics (n = 26), and salicylate analgesics (n = 26). We found signals of hearing loss with azacitidine, vaccines and nevirapine, immunosuppressants such as leflunomide, and biotherapies such as panitumumab and vandetanib. Prescribers should be informed about the potential associations with all these drugs. The role of the pathology itself and the known ototoxic drugs that can be associated do not allow to conclude definitively. Audiograms for the early detection of hearing loss induced by drugs known to be ototoxic are rarely carried out. Preventive treatments exist and must be considered.

Long-term vancomycin use had low risk of ototoxicity

Background

Vancomycin is a commonly used antibiotic with potent activity against Gram-positive organisms, but prolonged use and high doses can lead to toxicity. While vancomycin-associated nephrotoxicity is widely reported, few cases of ototoxicity have been described. The objective of this study was to determine the prevalence of negative changes in audiograms in patients receiving long-term intravenous (IV) vancomycin and to identify high-risk patients who need audiogram monitoring.

Methods

This was an IRB approved, cross-sectional study performed at an academic medical center from 1/2012-3/2019. Patients who were prescribed IV vancomycin for ≥ 14 days and had baseline and follow-up weekly audiometry were included. All data was extracted from the electronic medical record. The primary endpoint was worsening audiogram while on vancomycin. Descriptive and bivariate statistics were used to describe the patient population.

Results

424 patients were screened for inclusion; 92 received at least two audiograms while on vancomycin. Fifty-three percent of patients were men, the median (IQR) patient age was 44 (34–58) years, and 8% of patients had an estimated Cockcroft-Gault creatinine clearance ≤ 30 mL/min or received hemodialysis. The median (IQR) vancomycin exposure up until the last recorded audiogram was 30 (17–42) days. Vancomycin indications were: 53 (58%) bone and joint infections, 17 (18%) infective endocarditis, 10 (11%) bacteremia, 12 (13%) other infections. Seven (8%) patients experienced a worsening change in hearing from baseline, two (2%) of them suffered mild loss, two (2%) had mild to moderate loss, and three (3%) developed moderate-to-severe hearing loss. In bivariate analyses, no variables were found to be associated with a worsening change in audiogram, including baseline abnormal audiogram, age ≥ 40 years, elevated serum vancomycin levels, or vancomycin doses ≥ 4 grams/day.

Conclusions

The prevalence of negative changes in audiograms among patients receiving long-term intravenous vancomycin was low. The utility of routine audiogram testing in this population remains questionable except in high-risk patients; however, larger prospective studies with controls may be warranted to further explore the risk of ototoxicity.

Ototoxicity and Nephrotoxicity With Elevated Serum Concentrations Following Vancomycin Overdose: A Retrospective Case Series

Although a high vancomycin serum concentration is known to be associated with nephrotoxicity, its association with ototoxicity is not well known. The purpose of our study was to examine the latter association in pediatric patients, especially in cases of accidental overdose. Pediatric patients who received vancomycin at our facility between March 2010 and December 2015 with a serum trough concentration > 30 mg/L were enrolled. Age, sex, neonatal hearing screening results, estimated peak vancomycin serum concentration, duration of drug exposure, renal function, and hearing test results were collected. The estimated duration of concentrations above 30 or 80 mg/L were simulated with the Sawchuk-Zaske method. We defined a "high concentration" and "toxic concentration" of vancomycin as 30 to 80 mg/L and > 80 mg/L, respectively. Ototoxicity was assessed based on the auditory brain stem response. We identified 4 females and 2 males with normal hearing at birth. Four of the 6 patients were ≤ 3 months old. All the patients reached an estimated peak serum concentration of > 80 mg/L, and 5 exceeded 150 mg/L. The estimated duration of exposure to a high concentration and toxic concentration of vancomycin was 15 to 62 hours and 8 to 43 hours, respectively. All the patients experienced transient renal dysfunction. Although transient ototoxicity was found in 1 patient, prolonged ototoxicity was not observed in any of the patients. All the patients had received an accidental overdose of vancomycin. Prolonged hearing loss due to a high vancomycin serum concentration was not found in any of the subjects in the present report.

Age-dependent changes in vancomycin-induced nephrotoxicity in mice

Vancomycin hydrochloride (VCM) is a glycopeptide antibiotic that is commonly used to eradicate methicillin-resistant gram-positive cocci, despite its nephrotoxic side effects. Elderly people are particularly susceptible to developing VCM-induced nephrotoxicity. However, the precise mechanism by which VCM induces nephrotoxicity in elderly people is not completely understood. Therefore, we investigated VCM-induced nephrotoxicity in mice of different ages. VCM was injected intraperitoneally into mice at 1, 3, 6, 12, and 24 months of age at a dosage of 400 mg/kg body weight for 3 and 14 days. Twenty-four hours after the last injection, we examined plasma creatinine levels and histopathological alterations in the kidneys. VCM administration increased plasma creatinine levels, and these values gradually increased to higher levels with aging. The histological examination revealed renal tubular degeneration, such as brush-border atrophy, apoptosis/necrosis of the tubular epithelium, and epithelial desquamation, that gradually became more severe with aging. Furthermore, immunohistochemical staining with anti-CD10 and anti-single-stranded DNA antibodies revealed damaged renal proximal tubules with marked dilatation, as well as numerous apoptotic cells, and these features increased in severity in 12- and 24-month-old mice receiving VCM. Based on these results, aged mice were highly susceptible to kidney damage induced by VCM administration. In addition, proximal tubular epithelial cells likely underwent apoptosis after the administration of VCM. This report is the first to document VCM-induced nephrotoxicity in mice of different ages. Thus, this mouse model could be useful for understanding the mechanisms of VCM-induced nephrotoxicity in the elderly.

Eremomycin pyrrolidide: a novel semisynthetic glycopeptide with improved chemotherapeutic properties

PURPOSE

Development of new semisynthetic glycopeptides with improved antibacterial efficacy and reduced pseudoallergic reactions.

METHODS

Semisynthetic glycopeptides 3-6 were synthesized from vancomycin (1) or eremomycin (2) by the condensation with pyrrolidine or piperidine. The minimum inhibitory concentration (MIC) for the new derivatives was measured by the broth micro-dilution method on a panel of clinical isolates of Staphylococcus and Enterococcus. Acute toxicity (50% lethal dose, maximum tolerated doses), antibacterial efficacy on model of systemic bacterial infection with S. aureus and pseudoallergic inflammatory reaction (on concanavalin A) of eremomycin pyrrolidide (5) were evaluated in mice according to standard procedures.

RESULTS

The eremomycin pyrrolidide (5) was the most active compound and showed a high activity against Gram-positive bacteria: vancomycin-susceptible staphylococci and enterococci (minimum inhibitory concentrations [MICs] 0.13-0.25 mg/L), as well as vancomycin-intermediate resistant Staphylococcus aureus (MICs 1 mg/L). Antimicrobial susceptibility tested on a panel of 676 isolates showed that 5 had similar activity for the genera Staphylococcus and Enterococcus with MIC90=0.5 mg/L, while vancomycin had MIC90=1-2 mg/L. The number of resistant strains of Enterococcus faecium (vancomycin-resistant enterococci) (MIC =64 mg/L) with this value was 7 (8%) for vancomycin (1) and 0 for the compound 5. In vivo comparative studies in a mouse model of systemic bacterial infection with S. aureus demonstrated that the efficacy of 5 was notably higher than that of the original antibiotics 1 and 2. In contrast to 1, compound 5 did not induce pseudoallergic inflammatory reaction (on concanavalin A).

CONCLUSION

The new semisynthetic derivative eremomycin pyrrolidide (5) has high activity against staphylococci and enterococci including vancomycin-resistant strains. Compound 5 has a higher efficacy in a model of staphylococcal sepsis than vancomycin (1) or eremomycin (2). In striking contrast to natural antibiotics, the novel derivative 5 does not induce a pseudoallergic inflammatory reaction to concanavalin A and therefore has no histamine release activity. These results indicate the advantages of a new semisynthetic glycopeptide antibiotic eremomycin pyrrolidide (5) which may be a prospective antimicrobial agent for further pre-clinical and clinical evaluations.

Evaluation of risk factors for vancomycin-induced nephrotoxicity

Background Vancomycin is a glycopeptide antibiotic of choice for the treatment of serious infections caused by multi-resistant Gram-positive bacteria. However, vancomycin-associated nephrotoxicity (VAN) often limits its use. Previous data suggested a few risk factors of VAN, including higher mean vancomycin trough level, higher daily doses, old age, long duration of vancomycin therapy, and concomitant nephrotoxins. Objective To evaluate the incidence and risk factors of VAN and determine whether higher vancomycin trough concentrations were associated with a greater risk for VAN. Settings A retrospective, observational, single-center study at the 1960-bed university-affiliated tertiary care hospital (Samsung Medical Center), Seoul, Korea. Method A retrospective analysis of adult patients who received vancomycin parenterally in a tertiary care medical center from March 1, 2013 to June 30, 2013 was performed. We excluded patients with a baseline serum creatinine level > 2 mg/dL and those who had a history of end-stage renal disease and dialysis at baseline. The clinical characteristics were compared between patients with nephrotoxicity and those without nephrotoxicity to identify the risk factors associated with VAN. Main outcome measure Incidence of VAN and VAN-associated risk factors were analyzed. Results Of the 315 vancomycin-treated patients, nephrotoxicity occurred in 15.2% of the patients. In multivariate analysis, higher vancomycin trough concentrations of > 20 mg∕L (OR 9.57, 95% CI 2.49-36.83, p < 0.01) and intensive care unit (ICU) residence (OR 2.86, 95% CI 1.41-5.82, p < 0.01) were independently associated with VAN. Conclusion Our findings suggest that higher vancomycin trough levels and ICU residence might be associated with a greater risk for VAN. More careful monitoring of vancomycin serum trough levels and patient status might facilitate the timely prevention of VAN.

Evaluation of vancomycin therapy in the adult ICUs of a teaching hospital in southern Iran

BACKGROUND

Vancomycin resistance in intensive care units (ICUs) accounts for significant morbidity and excess costs. The objective of the present study was to determine the appropriateness of vancomycin use in the various ICUs of Nemazee Hospital, Shiraz, Iran.

METHODS

This prospective study was performed on 95 critically ill patients (48 males and 47 females) who were treated with vancomycin for at least 3 subsequent doses in 6 ICUs during 12 months. Required demographic, clinical, and paraclinical data were collected by a pharmacist. Fifteen indexes were considered for evaluation of vancomycin use.

RESULTS

Ventilator-associated hospital-acquired pneumonia (22.6%), sepsis (22.1%) and CNS infection (12.6%) were found to be the most important indications for vancomycin prescription. Vancomycin was prescribed empirically in 81% of patients. None of the patients received loading dose, and most of the patients received fixed dose. The rate of prolonged empiric antibiotic therapy was 68.5% in patients who received vancomycin. The mean score of vancomycin use in the ICUs of Nemazee Hospital was 7.1±0.6 out of 15, implying that the rate of vancomycin use was in accordance with the guideline proposed by the Department of Clinical Pharmacy of Nemazee Hospital based on Infectious Diseases Society of America by 47.3%.

CONCLUSION

Based on our results, the weakness in using vancomycin was related to not administering loading dose, the practice of prescribing fixed-dose vancomycin and prolonged duration of empiric therapy. Efforts to improve the pattern of vancomycin prescription and utilization in these ICUs should be undertaken.

Assessment of acute kidney injury in neurologically and traumatically injured intensive care patients receiving large vancomycin doses

Background:

Previous reports note that in a mixed patient population, vancomycin doses >4 g/day are associated with increased rates of acute kidney injury (AKI).

Objective:

The objective of the study is to determine if vancomycin regimens >4 g/day are associated with a higher incidence of AKI in neurocritical care unit (NCCU) and trauma/burn Intensive Care Unit (TBICU) patients.

Materials and Methods:

This single-centered, retrospective study enrolled adult patients initiated on vancomycin in the NCCU and TBICU at an academic medical center during 2016. Based on maximum steady-state dose exposure, patients were separated into two groups: ≤4 g/day and >4 g/day. The primary outcome of incidence of AKI was defined by the AKI Network criteria.

Results:

A total of 284 patients were screened for eligibility; 165 patients met inclusion criteria, 98 patients received ≤4 g/day and 67 patients received >4 g/day. The >4 g/day group had a lower mean age (32.6±11.1 vs. 47.8±16.2, P < 0.001), included more male patients (81% vs. 60%, P = 0.008), were more often treated for a central nervous system infection (31% vs. 11%, P = 0.001), had, on average, more concomitant use of nephrotoxic drugs (2.2±1.2 vs. 1.8±0.9, P = 0.02) and had a higher exposure to contrast (94% vs. 79%, P < 0.001). The primary outcome of AKI occurred in 14 patients receiving ≤4 g/day and five patients receiving >4 g/day which was not statistically significant (14% vs. 7%, P = 0.22).

Conclusions:

Our results indicate that administering >4 g/day of vancomycin to achieve therapeutic vancomycin troughs does not appear to lead to an increased incidence of AKI in a mixed NCCU and TBICU population.

Co-administration of vancomycin and piperacillin-tazobactam is associated with increased renal dysfunction in adult and pediatric burn patients

Background

Burn patients are prone to infections which often necessitate broad antibiotic coverage. Vancomycin is a common antibiotic after burn injury and is administered alone (V), or in combination with imipenem-cilastin (V/IC) or piperacillin-tazobactam (V/PT). Sparse reports indicate that the combination V/PT is associated with increased renal dysfunction. The purpose of this study was to evaluate the short-term impact of the three antibiotic administration types on renal dysfunction.

Methods

All pediatric and adult patients admitted to our centers between 2004 and 2016 with a burn injury were included in this retrospective review if they met the criteria of exposition to either V, V/IC, or V/PT for at least 48 h, had normal baseline creatinine, and no pre-existing renal dysfunction. Creatinine was monitored for 7 days after initial exposure; the absolute and relative increase was calculated, and patient renal outcomes were classified according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria depending on creatinine increases and estimated creatinine clearance. Secondary endpoints (demographic and clinical data, incidences of septicemia, and renal replacement therapy) were analyzed. Antibiotic doses were modeled in logistic and linear multivariable regression models to predict categorical KDIGO events and relative creatinine increase.

Results

Out of 1449 patients who were screened, 718 met the inclusion criteria, 246 were adults, and 472 were children. Between the study cohorts V, V/IC, and V/PT, patient characteristics at admission were comparable. V/PT administration was associated with a statistically higher serum creatinine, and lower creatinine clearance compared to patients receiving V alone or V/IC in adults and children after burn injury. The incidence of KDIGO stages 1, 2, and 3 was higher after V/PT treatment. In children, the incidence of KDIGO stage 3 following administration of V/PT was greater than after V/IC. In adults, the incidence of renal replacement therapy was higher after V/PT compared with V or V/IC. Multivariate modeling demonstrated that V/PT is an independent predictor of renal dysfunction.

Conclusion

Co-administration of vancomycin and piperacillin-tazobactam is associated with increased renal dysfunction in pediatric and adult burn patients when compared to vancomycin alone or vancomycin plus imipenem-cilastin. The mechanism of this increased nephrotoxicity remains elusive and warrants further scientific evaluation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1899-3) contains supplementary material, which is available to authorized users.

Vancomycin-Induced Leukocytoclastic Vasculitis and Acute Renal Failure Due to Tubulointerstitial Nephritis

BACKGROUND Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia and sepsis are commonly treated with intravenous vancomycin. However, vancomycin treatment is associated adverse reactions, including skin rashes and nephrotoxicity. We present a case of acute renal failure due to acute tubulointerstitial nephritis associated with a diffuse leukocytoclastic vasculitic skin eruption following intravenous vancomycin treatment. CASE REPORT A 79-year-old Caucasian male patient was treated with intravenous vancomycin for MRSA bacteremia. Prior to treatment, his creatinine was normal at 0.6 mg/dl. He presented one week later with shortness of breath, lower limb edema, and acute renal failure. He had a diffuse maculopapular rash involving the trunk and both upper and lower extremities. A renal biopsy and left arm skin biopsy were examined histologically. The skin biopsy showed leukocytoclastic vasculitis. Renal biopsy showed some sclerosed glomeruli, some with mesangial proliferation, and tubulointerstitial inflammation with eosinophils and plasma cells and mild interstitial fibrosis. Although there was some renal arteriolosclerosis, no vasculitic changes were seen, and no vascular thrombosis was present. A diagnosis of leukocytoclastic vasculitis and acute tubulointerstitial nephritis secondary to intravenous vancomycin therapy was made. CONCLUSIONS Although skin reactions associated with drug therapy are common, vancomycin-associated dermal vasculitis is rare. Tubulointerstitial nephritis is also a rare association with vancomycin treatment. This case report has highlighted that patients being treated with intravenous vancomycin should be carefully observed for acute skin rashes and deterioration in renal function, which can be managed by ceasing treatment with vancomycin, steroid challenge, and preventing future exposure to similar antimicrobial agents.

Multifunctional nanodiamonds in regenerative medicine: Recent advances and future directions

With recent advances in the field of nanomedicine, many new strategies have emerged for diagnosing and treating diseases. At the forefront of this multidisciplinary research, carbon nanomaterials have demonstrated unprecedented potential for a variety of regenerative medicine applications including novel drug delivery platforms that facilitate the localized and sustained release of therapeutics. Nanodiamonds (NDs) are a unique class of carbon nanoparticles that are gaining increasing attention for their biocompatibility, highly functional surfaces, optical properties, and robust physical properties. Their remarkable features have established NDs as an invaluable regenerative medicine platform, with a broad range of clinically relevant applications ranging from targeted delivery systems for insoluble drugs, bioactive substrates for stem cells, and fluorescent probes for long-term tracking of cells and biomolecules in vitro and in vivo. This review introduces the synthesis techniques and the various routes of surface functionalization that allow for precise control over the properties of NDs. It also provides an in-depth overview of the current progress made toward the use of NDs in the fields of drug delivery, tissue engineering, and bioimaging. Their future outlook in regenerative medicine including the current clinical significance of NDs, as well as the challenges that must be overcome to successfully translate the reviewed technologies from research platforms to clinical therapies will also be discussed.

Vancomycin Prophylaxis for Total Joint Arthroplasty: Incorrectly Dosed and Has a Higher Rate of Periprosthetic Infection Than Cefazolin

BACKGROUND

In total joint arthroplasty (TJA), vancomycin is used as perioperative antibiotic prophylaxis in patients with penicillin allergy or in patients colonized with methicillin-resistant Staphylococcus aureus (MRSA). Although vancomycin dosing should be weight-based (15 mg/kg), not all surgeons are aware of this; a fixed 1-g dose is instead frequently administered.

QUESTIONS/PURPOSES

(1) Is there a difference in the risk of periprosthetic joint infection (PJI) in patients receiving vancomycin or cefazolin prophylaxis after primary TJA? (2) What proportion of patients is adequately dosed with vancomycin? (3) Compared with actual fixed dosing, does weight-based dosing result in a greater proportion of patients staying above the recommended 15-mg/L level at the beginning and end of surgery? (4) Are patients overdosed with vancomycin at greater risk of developing nephrotoxicity and acute kidney injury?

METHODS

A single-institution, retrospective study was performed on 1828 patients undergoing primary TJAs who received vancomycin prophylaxis between 2008 and 2014. During the same period, 5810 patients underwent primary TJA and received cefazolin monotherapy. A chart review was performed to obtain patient characteristics, antibiotic dose and timing of administration, and microbiology data. Adequate vancomycin dosing was defined as 15 mg/kg and within the 125-mg range. Vancomycin levels were calculated at the beginning and end of surgery using pharmacokinetic equations. Levels of 15 mg/L were considered adequate. Logistic regression, chi square tests, and analysis of variance were performed.

RESULTS

Among primary TJAs, patients receiving vancomycin had a higher rate of PJI (32 of 1828 [2%]) compared with patients receiving cefazolin prophylaxis (62 of 5810 [1%]; adjusted odds ratio, 1.587 [1.004-2.508]; p = 0.048). Ten percent of PJIs in the vancomycin underdosed group (two of 20) was caused by MRSA, and no patients with adequate dosing or overdosing of vancomycin developed PJI with MRSA. Of all procedures in which vancomycin monotherapy was used, 28% (518 of 1828) was adequately dosed according to weight-based dosage recommendations. Furthermore, 94% (1726 of 1828) of patients received a fixed 1-g dose of vancomycin, of whom 64% (1105 of 1726) were underdosed. All patients had vancomycin infusion initiated within 2 hours before incision. A weight-based protocol would have resulted in fewer patients having unacceptably low vancomycin levels (< 15 mg/L) compared with those with actual fixed dosing, both for the beginning of surgery at the time of incision (zero of 1828 [0%] versus 471 of 1828 [26%]; odds ratio, 0.001 [0.000-0.013]; p < 0.001) and at the end of surgery (33 of 1828 [2%] versus 746 of 1828 [41%]; odds ratio, 0.027 [0.019-0.038]; p < 0.001). Between the vancomycin dosage groups, there were no differences in the rate of nephrotoxicity (underdosed: 12 of 1130 [1%], adequately dosed: five of 518 [1%], overdosed: four of 180 [2%], p = 0.363) and acute kidney injury (underdosed: 28 of 1130 [2%], adequately dosed: 10 of 518 [2%], overdosed: six of 180 [3%], p = 0.561).

CONCLUSIONS

The majority of patients given vancomycin prophylaxis are underdosed according to the weight-based dosage recommendations, and MRSA did not occur in patients who were adequately dosed with vancomycin. Surgeons should thus ensure that their patients are adequately dosed with vancomycin using the recommendation of 15 mg/kg and that the dose of vancomycin is administered in a timely fashion. Furthermore, and based on the findings of this study, we have moved toward limiting the utilization of vancomycin prophylaxis for patients undergoing elective arthroplasty at our institution.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The cumulative effects of intravenous antibiotic treatments on hearing in patients with cystic fibrosis

BACKGROUND

Aminoglycosides (AGs) and glycopeptides are antibiotics essential for treating life-threatening respiratory infections in patients with cystic fibrosis (CF). The goal of this study was to examine the effects of cumulative intravenous (IV)-AG (amikacin and/or tobramycin) and/or glycopeptide (vancomycin) dosing on hearing status in patients with CF.

METHODS

Hearing thresholds were measured from 0.25 to 16.0kHz, in 81 participants with CF. Participants were categorized into two groups: normal hearing in both ears (≤25dB HL for all frequency bands) or hearing loss (>25dB HL for any frequency band in either ear). Participants were also characterized into quartiles by their cumulative IV-AG (with or without vancomycin) exposure. Dosing was calculated using two strategies: (i) total number of lifetime doses, and (ii) total number of lifetime doses while accounting for the total doses per day. This was referred to as the "weighted" method.

RESULTS

Participants in the hearing loss group were significantly older than those in the normal-hearing group. After adjusting for gender and age at the time of hearing test, participants in the two highest-quartile exposure groups were almost 5 X more likely to have permanent sensorineural hearing loss than those in the two lowest-quartile exposure groups. There was a small group of CF patients who had normal hearing despite high exposure to IV-antibiotics.

CONCLUSIONS

Cumulative IV-antibiotic dosing has a significant negative effect on hearing sensitivity in patients with CF, when controlling for age and gender effects. A trend for increasing odds of hearing loss was associated with increasing cumulative IV-antibiotic dosing.

Review on Usage of Vancomycin in Livestock and Humans: Maintaining Its Efficacy, Prevention of Resistance and Alternative Therapy

Vancomycin is one of the “last-line” classes of antibiotics used in the treatment of life-threatening infections caused by Gram-positive bacteria. Even though vancomycin was discovered in the 1950s, it was widely used after the 1980s for the treatment of infections caused by methicillin-resistant Staphylococci, as the prevalence of these strains were increased. However, it is currently evident that vancomycin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci have developed for various reasons, including the use of avaparcin—an analog of vancomycin—as a feed additive in livestock. Therefore, prophylactic and empiric use of antibiotics and their analogues need to be minimized. Herein we discuss the rational use of vancomycin in treating humans, horses, farm animals, and pet animals such as dogs, cats, and rabbits. In present day context, more attention should be paid to the prevention of the emergence of resistance to antibiotics in order to maintain their efficacy. In order to prevent emergence of resistance, proper guidance for the responsible use of antimicrobials is indispensable. Therefore, almost all stakeholders who use antibiotics should have an in-depth understanding of the antibiotic that they use. As such, it is imperative to be aware of the important aspects of vancomycin. In the present review, efforts have been made to discuss the pharmacokinetics and pharmacodynamics, indications, emergence of resistance, control of resistance, adverse effects, and alternative therapy for vancomycin.

Vancomycin and the Risk of AKI: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Vancomycin has been in use for more than half a century, but whether it is truly nephrotoxic and to what extent are still highly controversial. The objective of this study was to determine the risk of AKI attributable to intravenous vancomycin.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a systematic review of randomized, controlled trials and cohort studies that compared patients treated with intravenous vancomycin with a control group of patients given a comparator nonglycopeptide antibiotic and in which kidney function or kidney injury outcomes were reported. PubMed and Cochrane Library were searched from 1990 to September of 2015. Two reviewers extracted data and assessed study risk of bias, and one reviewer adjudicated the assessments. A meta-analysis was conducted on seven randomized, controlled trials (total of 4033 patients).

RESULTS

Moderate quality evidence suggested that vancomycin treatment is associated with a higher risk of AKI, with a relative risk of 2.45 (95% confidence interval, 1.69 to 3.55). The risk of kidney injury was similar in patients treated for skin and soft tissue infections compared with those treated for nosocomial pneumonia and other complicated infections. There was an uncertain risk of reporting bias, because kidney function was not a prespecified outcome in any of the trials. The preponderance of evidence was judged to be indirect, because the majority of studies compared vancomycin specifically with linezolid.

CONCLUSIONS

Our findings suggest that there is a measurable risk of AKI associated with vancomycin, but the strength of the evidence is moderate. A randomized, controlled trial designed to study kidney function as an outcome would be needed to draw unequivocal conclusions.

Review of vancomycin-induced renal toxicity: an update

In recent times the use of larger doses of vancomycin aimed at curbing the increasing incidence of resistant strains of Staphylococcus aureus has led to a wider report of acute kidney injury (AKI). Apart from biological plausibility, causality is implied by the predictive association of AKI with larger doses, longer duration, and graded plasma concentrations of vancomycin. AKI is more likely to occur with the concurrent use of nephrotoxic agents, and in critically ill patients who are susceptible to poor renal perfusion. Although most vancomycin-induced AKI cases are mild and therefore reversible, their occurrence may be associated with greater incidence of end-stage kidney disease and higher mortality rate. The strategy for its prevention includes adequate renal perfusion and therapeutic drug monitoring in high-risk individuals. In the near future, there is feasibility of renoprotective use of antioxidative substances in the delivery of vancomycin.

Effect of sepsis and systemic inflammatory response syndrome on neonatal hearing screening outcomes following gentamicin exposure

OBJECTIVES

Hearing loss in neonatal intensive care unit (NICU) graduates range from 2% to 15% compared to 0.3% in full-term births, and the etiology of this discrepancy remains unknown. The majority of NICU admissions receive potentially ototoxic aminoglycoside therapy, such as gentamicin, for presumed sepsis. Endotoxemia and inflammation are associated with increased cochlear uptake of aminoglycosides and potentiated ototoxicity in mice. We tested the hypothesis that sepsis or systemic inflammatory response syndrome (SIRS) and intravenous gentamicin exposure increases the risk of hearing loss in NICU admissions.

METHODS

The Institutional Review Board at Oregon Health & Science University (OHSU) approved this study design. Two hundred and eight infants met initial criteria, and written, informed consent were obtained from parents or guardians of 103 subjects ultimately enrolled in this study. Prospective data from 91 of the enrolled subjects at OHSU Doernbecher Children's Hospital Neonatal Care Center were processed. Distortion product otoacoustic emissions (DPOAEs; f2 frequency range: 2063-10,031 Hz) were obtained prior to discharge to assess auditory performance. To pass the DPOAE screen, normal responses in >6 of 10 frequencies in both ears were required; otherwise the subject was considered a "referral" for a diagnostic hearing evaluation after discharge. Cumulative dosing data and diagnosis of neonatal sepsis or SIRS were obtained from OHSU's electronic health record system, and the data processed to obtain risk ratios.

RESULTS

Using these DPOAE screening criteria, 36 (39.5%) subjects would be referred. Seventy-four (81%) subjects had intravenous gentamicin exposure. Twenty (22%) had ≥4 days of gentamicin, and 71 (78%) had <4 days. The risk ratio (RR) of referral with ≥4 days of gentamicin was 1.92 (p=0.01). Eighteen subjects had sepsis or met neonatal SIRS criteria, 9 of whom had ≥5 days of gentamicin and a DPOAE referral risk ratio of 2.12 (p=0.02) compared to all other subjects. Combining subjects with either vancomycin or furosemide overlap with gentamicin treatment yielded an almost significant risk ratio (RR=1.77, p=0.05) compared to the rest of the cohort.

CONCLUSIONS

We report an increased risk of referral with DPOAE screening for those receiving ≥4 days of intravenous gentamicin administration that may contribute to the greater prevalence of hearing loss in NICU graduates. We propose an expanded prospective study to gather a larger cohort of subjects, identifying those with sepsis or neonatal SIRS, to increase the statistical power of this study design. Subsequent studies also need to obtain follow-up diagnostic audiological data to verify whether the outcomes of DPOAE screening, in addition to the standard AABR screen, is a reliable predictor of permanent hearing loss following gentamicin exposure in the NICU.

Protective Effects of Cilastatin against Vancomycin-Induced Nephrotoxicity

Vancomycin is a very effective antibiotic for treatment of severe infections. However, its use in clinical practice is limited by nephrotoxicity. Cilastatin is a dehydropeptidase I inhibitor that acts on the brush border membrane of the proximal tubule to prevent accumulation of imipenem and toxicity. The aim of this study was to investigate the potential protective effect of cilastatin on vancomycin-induced apoptosis and toxicity in cultured renal proximal tubular epithelial cells (RPTECs). Porcine RPTECs were cultured in the presence of vancomycin with and without cilastatin. Vancomycin induced dose-dependent apoptosis in cultured RPTECs, with DNA fragmentation, cell detachment, and a significant decrease in mitochondrial activity. Cilastatin prevented apoptotic events and diminished the antiproliferative effect and severe morphological changes induced by vancomycin. Cilastatin also improved the long-term recovery and survival of RPTECs exposed to vancomycin and partially attenuated vancomycin uptake by RPTECs. On the other hand, cilastatin had no effects on vancomycin-induced necrosis or the bactericidal effect of the antibiotic. This study indicates that cilastatin protects against vancomycin-induced proximal tubule apoptosis and increases cell viability, without compromising the antimicrobial effect of vancomycin. The beneficial effect could be attributed, at least in part, to decreased accumulation of vancomycin in RPTECs.

How to use vancomycin optimally in neonates: remaining questions

In neonates, vancomycin, a narrow-spectrum antibiotic, is the first choice of treatment of late-onset sepsis predominantly caused by Gram-positive bacteria (coagulase-negative staphylococci and enterococci). Although it has been used for >50 years, prescribing the right dose and dosing regimen remains a challenge in neonatal intensive care units for many reasons including high pharmacokinetic variability, increase in the minimal inhibition concentration against staphylococci, lack of consensus on dosing regimen and way of administration (continuous or intermittent), duration of treatment, use of therapeutic drug monitoring, limited data on short- and long-term toxicity, risk of mutant selection and errors of administration linked to concentrated formulations. This article highlights and discusses future research directions, with specific attention given to dosing optimization of vancomycin, including the advantages of modeling and simulation approaches.

Novel Antibiotic-loaded Point-of-care Implant Coating Inhibits Biofilm

BACKGROUND

Orthopaedic biomaterials are susceptible to biofilm formation. A novel lipid-based material has been developed that may be loaded with antibiotics and applied as an implant coating at point of care. However, this material has not been evaluated for antibiotic elution, biofilm inhibition, or in vivo efficacy.

QUESTIONS/PURPOSES

(1) Do antibiotic-loaded coatings inhibit biofilm formation? (2) Is the coating effective in preventing biofilm in vivo?

METHODS

Purified phosphatidylcholine was mixed with 25% amikacin or vancomycin or a combination of 12.5% of both. A 7-day elution study for coated titanium and stainless steel coupons was followed by turbidity and zone of inhibition assays against Staphylococcus aureus and Pseudomonas aeruginosa. Coupons were inoculated with bacteria and incubated 24 hours (N = 4 for each test group). Microscopic images of biofilm were obtained. After washing and vortexing, attached bacteria were counted. A mouse biofilm model was modified to include coated and uncoated stainless steel wires inserted into the lumens of catheters inoculated with a mixture of S aureus or P aeruginosa. Colony-forming unit counts (N = 10) and scanning electron microscopy imaging of implants were used to determine antimicrobial activity.

RESULTS

Active antibiotics with colony inhibition effects were eluted for up to 6 days. Antibiotic-loaded coatings inhibited biofilm formation on in vitro coupons (log-fold reductions of 4.3 ± 0.4 in S aureus and 3.1 ± 0 for P aeruginosa in phosphatidylcholine-only coatings, 5.6 ± 0 for S aureus and 3.1 ± 0 for P aeruginosa for combination-loaded coatings, 5.5 ± 0.3 for S aureus in vancomycin-loaded coatings, and 3.1 ± 0 for P aeruginosa for amikacin-loaded coatings (p < 0.001 for all comparisons of antibiotic-loaded coatings against uncoated controls for both bacterial strains, p < 0.001 for comparison of antibiotic-loaded coatings against phosphatidylcholine only for S aureus, p = 0.54 for comparison of vancomycin versus combination coating in S aureus, P = 0.99 for comparison of antibiotic- and unloaded phosphatidylcholine coatings in P aeruginosa). Similarly, antibiotic-loaded coatings reduced attachment of bacteria to wires in vivo (log-fold reduction of 2.54 ± 0; p < 0.001 for S aureus and 0.83 ± 0.3; p = 0.112 for P aeruginosa).

CONCLUSIONS

Coatings deliver active antibiotics locally to inhibit biofilm formation and bacterial growth in vivo. Future evaluations will include orthopaedic preclinical models to confirm therapeutic efficacy.

CLINICAL RELEVANCE

Clinical applications of local drug delivery coating could reduce the rate of implant-associated infections.

In vitro antibacterial effects of Cinnamomum extracts on common bacteria found in wound infections with emphasis on methicillin-resistant Staphylococcus aureus

ETHNOPHARMACOLOGICAL RELEVANCE

Cinnamomum species have been widely used in many traditional systems of medicine around the world. In the Malaysian traditional system of medicine, the leaves, stem bark and stem wood of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum have been used to treat wound infections. To study the antibacterial effects of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum against common bacteria found in wound infections with primary focus on methicillin-resistant Staphylococcus aureus (MRSA).

MATERIALS AND METHODS

The crude extracts from the leaves, stem-bark and stem-wood of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum were obtained using sequential extraction with hexane, ethylacetate, methanol and water. The volatile oils were obtained by hydro-distillation. The antibacterial activities of extracts were investigated using disk diffusion assays and broth microdilution assays.

RESULTS

The volatile oils obtained from the stem-bark of Cinnamomum altissimum, Cinnamomum porrectum and Cinnamomum impressicostatum have shown significant antibacterial activity against a wide range of Gram positive and Gram negative bacteria including MRSA. A few test extracts have shown better activity against MRSA as compared to methicillin sensitive Staphylococcus aureus (MSSA). Amongst all the test extracts, Cinnamomum impressicostatum stem-bark water extract produced the largest inhibition zone of 21.0mm against MRSA while its inhibition zone against MSSA was only 8.5mm. The minimum inhibitory concentration (MIC) of this extract against MRSA was 19.5 μg mL(-1) and the corresponding minimum bactericidal concentration (MBC) was 39.0 μg mL(-1).

CONCLUSIONS

This study has scientifically validated the traditional use of Cinnamomum species in treating wound infections. Of high scientific interest was the observation that the antibacterial effect of Cinnamomum impressicostatum stem-bark crude water extract against MRSA was significantly higher than its effect against MSSA, suggesting that the extract contains a compound(s) with higher specific neutralising activity against the drug resistance markers of MRSA.

Antimicrobial agents, drug adverse reactions and interactions, and cancer

The intent of this chapter is to review the types of adverse drug reactions and interactions associated with antimicrobial agents, specifically in the setting of patients with malignancies. The initial sections will discuss categorizing and describing the mechanisms of adverse reactions and interactions. The later sections include a detailed discussion about adverse reactions and drug interactions associated with commonly used antibacterial, antiviral, and antifungal agents in this subpopulation. Where relevant, the clinical use and indication for the drugs will be reviewed. The antibacterial section will specifically address the emergence of antimicrobial resistance and drugs of last resort (newer agents, such as linezolid and daptomycin and novel uses of older previously retired agents, such as polymyxin B). The antifungal section will address the ramification of pharmacokinetic interactions and the need to measure drug levels. The chapter is not meant to be exhaustive and as such will not extensively address all antimicrobials or all interactions for each of these agents.

Underlying the mechanism of vancomycin and human serum albumin interaction: a biophysical study

In the present study, the binding mechanism of vancomycin with human serum albumin (HSA) was determined. Upon addition of vancomycin to HSA, the fluorescence emission was quenched and the binding constant of vancomycin with HSA was found to be 6.05 × 10(3) M(-1) at 295 K, which corresponds to -2.16 × 10(4) J·mol(-1) of free energy. The conformation of HSA was altered upon binding of vancomycin with a decrease in α helix and an increase in β sheets and random coils, suggesting partial unfolding of the secondary structure. Molecular docking experiments found that vancomycin binds strongly with HSA at the hydrophobic pocket through hydrogen bonding and van der Waals interactions. An average binding distance of 4.71 nm has been determined on the basis of the Förster resonance energy theory. It was demonstrated that vancomycin binding to HSA causes protein structural changes.

Antibiotics and Antifungals in Neonatal Intensive Care Units: A Review

The incidence of infections is higher in the neonatal period than at any time of life. The basic treatment of infants with infection has not changed substantially over the last years. Antibiotics (with or without supportive care) are one of the most valuable resources in managing sick newborn babies. Early-onset (ascending or transplacental) or late-onset (hospital acquired) infections present different chronology, epidemiology, physiology and outcome. Some classes of antibiotics are frequently used in the neonatal period: penicillins, cephalosporins, aminoglycosides, glycopeptides, monobactams, carbapenems. Other classes of antibiotics (chloramphenicol, cotrimoxazole, macrolides, clindamycin, rifampicin and metronidazole) are rarely used. Due to emergence of resistant bacterial strains in Neonatal Intensive Care Units (NICU), other classes of antibiotics such as quinolones and linezolid will probably increase their therapeutic role in the future. Although new formulations have been developed for treatment of fungal infections in infants, amphotericin B remains first-line treatment for systemic Candida infection. Prophylactic antibiotic therapy is almost always undesirable. Challenges from pathogens and antibiotic resistance in the NICU may warrant modification of traditional antibiotic regimens. Knowledge of local flora and practical application of different antibiotic characteristics are key to an effective and safe utilization of antibiotics and antifungals in critical newborns admitted to the NICU, and especially in very low birth weight infants.

[Drug-induced fever: a diagnosis to remember]

Drug fever (DF) is a febrile reaction induced by a drug without additional clinical features like skin eruption. This adverse drug reaction is probably common but under diagnosed. While its outcome is generally favourable, DF generates unnecessary diagnostic procedures as well as hospitalisations or hospitalisation prolongations. Clinical presentation and biological findings are not specific. Fever is generally well tolerated but may be accompanied by general symptoms mimicking sepsis. Moderate biological disorders could be expected, including elevation or decrease in white blood cell count, eosinophilia, liver cytolysis, and increased C-reactive protein. An infection should be systematically ruled out. Clinical or biological signs of severity should question DF diagnosis. When DF is suspected, the involved drug(s) should be stopped after a reliable assessment of imputability. Antibiotics represent the most often implicated drugs. Fever disappearance after discontinuing the suspected drug is the cornerstone of DF diagnosis. Before stopping the administration of the suspected drug(s), a risk/benefit ratio assessment is necessary. Consistently, it may be complicated to stop an antimicrobial drug when treating an infection or an immunosuppressive drug if required.

Use of antibacterial agents in the neonate: 50 years of experience with vancomycin administration

Neonatal sepsis, classified as either early or late onset, has specific pathogen distribution and infection rates in the different neonatal age groups. It is a major cause of mortality and morbidity and administration of antibiotics is urgently required for suspected or proven infection. Vancomycin is the first choice treatment of late onset sepsis due to resistant staphylococci. Although it has been used for more than 50 years, prescription remains a challenge in neonatal intensive care units for many reasons, including: high pharmacokinetic variability, numerous presentations, lack of consensus on dosing regimen and therapeutic drug monitoring. In addition, recent concerns about the increase in minimal inhibition concentration and other more generic problems have prompted reappraisal of the rational use of vancomycin. This article highlights the goal of optimising vancomycin therapy in the neonate and discusses future research directions. Specific attention is given to dosing optimisation of vancomycin to avoid resistance and maximise the likelihood of achieving the therapeutic target. Modelling and simulation approaches have clear advantages in dosing optimisation of antimicrobial agents in the neonate. Neonatologists and paediatric pharmacologists should work closely together to achieve this goal.

Drug Fever: a descriptive cohort study from the French national pharmacovigilance database

BACKGROUND

Although known as a rare adverse drug reaction (ADR), drug fever (DF) remains an important issue in medicine, with the risk of leading to inappropriate and potentially harmful diagnostic and therapeutic interventions. Only sparse data regarding DF have been published.

OBJECTIVE

The aim of the study was to investigate which drugs were associated with DF, and report outcomes.

METHODS

Cases of DF without skin reactions were selected from all ADRs reported from 1986 to 2007 in the French National Pharmacovigilance Database. Drugs potentially responsible for DF were assessed using a qualitative case-by-case analysis (Naranjo's criteria) and quantitative measurement (proportional reporting ratio [PRR]). A drug was implicated as the cause of DF when the following criteria were validated: three or more cases and PRR of at least two with a Chi-squared value of at least four.

RESULTS

A total of 167 DF cases involving 115 drugs were eligible. Based on the PRR, 22 drugs were significantly associated with DF. Antibacterials represented the most frequently reported drugs, including amikacin (PRR 39.6 [95% CI 23.6, 69.0], oxacillin (9.1 [3.6, 23.4]), cefotaxime (5.5 [2.0, 15.3]), ceftriaxone (5.4 [2.6, 11.3]), rifampicin (4.0 [1.8, 9.2]), vancomycin (4.0 [1.4, 11.5]), ciprofloxacin (3.1 [1.2, 8.0]), isoniazid (3.9 [1.4, 11.4]), pristinamycin (3.1 [1.0, 9.1]) and cotrimoxazole (2.6 [1.2, 5.8]). Median time [interquartile range] from drug administration to fever onset was 2 days [1.0-10.5]. A diagnosis of DF was made following cessation of the suspected drugs (3 days [1.0-11.5] after fever onset. Drug rechallenge was performed (38.0%), resulting in recurrence of DF in all cases. DF resulted in life-threatening events (0.6%), hospitalization or prolonged hospital stay (24.5%) and persistent disability (0.6%). Final outcome was favourable in 96.9% of cases after drug discontinuation.

CONCLUSION

Diagnosing DF is challenging. Based on this large series, antibacterials remain the major class of drugs responsible for DF.

Initial dose of vancomycin based on body weight and creatinine clearance to minimize inadequate trough levels in Japanese adults

Our aims were to elucidate the factors that affected vancomycin (VCM) serum trough levels and to find the optimal initial dose based on creatinine clearance (CrCl) and body weight (BW) to minimize inadequate trough levels in a retrospective observational study among Japanese adults. One hundred and six inpatients, in whom VCM trough levels were measured after completing the third dosing, were consecutively recruited into our study in a tertiary hospital. We considered the frequency of <30% as low. In the generalized linear model, initial VCM total daily dose, CrCl, and BW were independent risk factors of VCM trough levels. In patients with CrCl ≥30 and <50 mL/min, 1 g/day yielded low frequencies of a trough level of ≥20 mcg/mL, regardless of BW. In patients with CrCl ≥50 mL/min, 2 g/day yielded low frequencies of a trough level of <10 mcg/mL in patients weighing <55 kg, but not in patients weighing ≥55 kg. Optimal VCM initial total daily dose may be 1 g/day in patients with CrCl ≥30 and <50 mL/min regardless of BW and 2 g/day in patients weighing <55 kg with CrCl ≥50 mL/min among Japanese adults.

Biopsy-Proven Acute Tubular Necrosis due to Vancomycin Toxicity

Vancomycin (VAN) has been associated with acute kidney injury (AKI) since it has been put into clinical use in the 1950's. Early reports of AKI were likely linked to the impurities of the VAN preparation. With the advent of the more purified forms of VAN, the incidence of AKI related to VAN were limited to acute interstitial nephritis (AIN) or as a potentiating agent to other nephrotoxins such as Aminoglycosides. VAN as the sole etiologic factor for nephrotoxic acute tubular necrosis (ATN) has not been described. Here, we report a case of biopsy-proven ATN resulting from VAN.

Use of vancomycin pharmacokinetic-pharmacodynamic properties in the treatment of MRSA infections

Vancomycin is a commonly used antimicrobial in patients with methicillin-resistant Staphylococcus aureus (MRSA) infections. Increasing vancomycin MIC values in MRSA clinical isolates makes the optimization of vancomycin dosing pivotal to its continued use. Unfortunately, limited data exist regarding the optimal pharmacokinetic-pharmacodynamic (PK-PD) goal to improve bacterial killing and clinical outcomes with vancomycin. The hallmark study in this area suggests that achieving an AUC to MIC ratio of over 400 improves the likelihood of achieving these outcomes. Challenges in the implementation of PK-PD-based dosing for vancomycin include current methodologies utilized in microbiology laboratories, as well as intra- and interpatient pharmacokinetic variability. Individualized dosing based on MIC and specific patient factors is important to achieve optimal outcomes from vancomycin therapy.

Inhibitory and resistance-modifying potential of plant-based alkaloids against methicillin-resistant Staphylococcus aureus (MRSA)

Increased prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has become a major threat to the health sector worldwide due to their virulence, limited therapeutic options and their distribution in both hospital and community settings. Discovery and development of new anti-MRSA agents as alternatives to the very few antibiotics left in the armamentarium are, thus, urgently required. Recently, an efflux mechanism in MRSA has been identified as one of the main contributors of resistance towards various structurally unrelated antibiotics. The potential of reserpine (a phytoalkaloid) as efflux pump inhibitor (EPI) against various microbes remains limited as the concentration needed for inhibition is toxic to humans. This study therefore aimed to evaluate 13 alkaloid compounds as potential inhibitory agents and/or potential EPIs against a panel of three MRSA isolates which not only differ in their susceptibility to vancomycin (amongst the last drugs available to treat serious MRSA infection), but also exhibited active efflux activity. Results indicated berberine's moderate inhibitiory activity against two MRSA isolates scoring a minimum inhibitory concentration (MIC) value of 125 microg/ml. Notable efflux inhibitory activity (ranging from two- to eightfold Ethidium Bromide MIC reduction) meanwhile was detected from quinine, piperine and harmaline using reserpine as the positive control. Findings from this study support the opinion that a vast number of potential phytocompounds with pharmacological potential await discovery. Therapeutic application of these compounds, however, warrants further investigation to ascertain their pharmacodynamics and safety aspects.

Characterising vancomycin's immunotoxic profile using Swiss and CFW mice as an experimental model

Immunotoxicology can lead to determining the adverse effects of different compounds on the immune system. Sometimes, many drugs (especially antibiotics) induce immune alterations, mainly auto-immunity. This study was aimed at determining vancomycin's immunotoxic effect by comparing the original molecule to two of the most used copies. Thirty-two mice from two murine strains (Swiss and CFW) were treated with three antibiotic formulations for studying its effect on splenic lymphoid and peripheral blood cell populations by using haemograms, flow cytometry and blastogenesis assays. The results indicated that vancomycin produces neutropenia and lymphocytosis in peripheral populations and that it induces a selective immunomodulatory effect on splenocyte sub-populations, depending on formulation and the strain so treated.