Disproportionality Analysis of Safety with Nafcillin and Oxacillin with the FDA Adverse Event Reporting System (FAERS).

Antistaphylococcal penicillins such as nafcillin and oxacillin are among the first choices of treatment for severe invasive methicillin-susceptible Staphylococcus aureus (MSSA) infections, although there has been limited safety evaluations between individual agents. Using the FDA Adverse Event Reports System (FAERS), oxacillin was observed to have a lower proportion of reports of acute renal failure (reporting odds ratio [ROR], 5.3 [95% confidence interval {CI}, 3.1 to 9.3] versus 21.3 [95% CI, 15.8 to 28.6], respectively) and hypokalemia (ROR, 0.7 [95% CI, 0.1 to 4.8] versus 11.4 [95% CI, 7.1 to 18.3], respectively) than nafcillin.

Retrospective Analysis of Adverse Drug Events Between Nafcillin Versus Cefazolin for Treatment of Methicillin-Susceptible Staphylococcus aureus Infections.

Background: Nafcillin or cefazolin are drugs of choice for methicillin-susceptible Staphylococcus aureus (MSSA) infections. Prior studies indicate a higher incidence of acute kidney injury (AKI) with nafcillin, although AKI classification and time to occurrence is not well described. Objective: To characterize the incidence and time to adverse drug events for nafcillin versus cefazolin in the inpatient setting. Methods: A retrospective cohort study evaluated hospitalized, adult patients receiving intravenous nafcillin or cefazolin for treatment of MSSA infection. Incidence and time to AKI based on RIFLE criteria were measured. Secondary end points included antibiotic discontinuation and incidence of neutropenia, thrombocytopenia, elevated transaminases, and Clostridioides difficile infection (CDI). Results: Of 324 patients who received nafcillin (n = 119) or cefazolin (n = 205), higher rates of AKI were found for nafcillin versus cefazolin (19% vs 2%, respectively; P < 0.0001). Median time to AKI with nafcillin was 6.5 days (range, 3-14 days). The majority of patients were classified as RIFLE "Risk" stratum. Nafcillin treatment discontinuations were more frequent than for cefazolin (17.6% vs 0.9%, respectively; P < 0.0001). Nafcillin was an independent predictor of AKI (odds ratio = 12.4; 95% CI = 4.14-47.60, P < 0.0001). No differences in neutropenia, thrombocytopenia, elevated transaminases, or CDI were observed. Conclusion and Relevance: Nafcillin displayed higher rates of AKI at a median of 1 week of therapy, which provides a framework for clinician monitoring and consideration of antibiotic modification. Most patients developed "Risk" class AKI (RIFLE classification), which may be reversible with prompt intervention.

Reversion From Methicillin Susceptibility to Methicillin Resistance in Staphylococcus aureus During Treatment of Bacteremia.

Approximately 3% of Staphylococcus aureus strains that, according to results of conventional phenotypic methods, are highly susceptible to methicillin-like antibiotics also have polymerase chain reaction (PCR) results positive for mecA. The genetic nature of these mecA-positive methicillin-susceptible S. aureus (MSSA) strains has not been investigated. We report the first clearly defined case of reversion from methicillin susceptibility to methicillin resistance among mecA-positive MSSA within a patient during antibiotic therapy. We describe the mechanism of reversion for this strain and for a second clinical isolate that reverts at a similar frequency. The rates of reversion are of the same order of magnitude as spontaneous resistance to drugs like rifampicin. When mecA is detected by PCR in the clinical laboratory, current guidelines recommend that these strains be reported as resistant. Because combination therapy using both a ß-lactam and a second antibiotic suppressing the small revertant population may be superior to alternatives such as vancomycin, the benefits of distinguishing between mecA-positive MSSA and MRSA in clinical reports should be evaluated.

Staphylococcal Scalded Skin Syndrome: A Case Review.

Staphylococcal scalded skin syndrome (SSSS) is a rare yet well-known exfoliative skin syndrome. It involves extensive desquamated areas caused by an exfoliative toxin from Staphylococcus aureus. The typical presentation of SSSS allows for early diagnosis and treatment of the disease. Knowing and understanding the prevalence, pathophysiology, risk factors, and diagnosis of SSSS will ensure that infants being treated and cared for by neonatal nurses and neonatal nurse practitioners will receive appropriate, comprehensive, and multidisciplinary care while in the NICU. The purpose of this case review is to inform neonatal nurses and practitioners of the current literature that focuses on the diagnosis and management of SSSS.

Physical Compatibility of Intravenous Ondansetron Hydrochloride and Nafcillin Sodium.

Information on the physical compatibility of intravenous (IV) medications is vital for patient care and safety in acute care settings. Drug information resources list ondansetron and nafcillin as IV compatible, however, bolus concentrations of ondansetron are not reported. This study investigated the in vitro physical compatibility of bolus and infusion concentrations of ondansetron hydrochloride with nafcillin sodium. Two admixtures were prepared: 1) ondansetron hydrochloride 2 mg/mL and nafcillin sodium 20 mg/mL, and 2) ondansetron hydrochloride 0.16 mg/mL and nafcillin sodium 20 mg/mL. The admixtures were prepared in triplicate using aseptic technique according to manufacturer guidance and stored at room temperature (22-23 °C) for up to 24 hours. Admixtures were examined for visual precipitation, turbidity, and pH at baseline and at 1, 5, 8, and 24 hours. Admixture 1 developed a haze immediately after mixing, which was sustained over 24 hours. There was a demonstrative change in absorbance after 1 hour, but pH remained stable until hour 24. Admixture 2 developed a haze at 5 hours, but the absorbance and pH remained stable until hour 24; a decrease in the pH was observed in all samples at hour 24. This in vitro study revealed that ondansetron hydrochloride 2 mg/mL and nafcillin sodium 20 mg/mL are not physically compatible when administered through the same IV line. No demonstrative change was observed with ondansetron hydrochloride 0.16 mg/mL and nafcillin sodium 20 mg/mL; however, concurrent administration of these medications is questionable when delivered through an IV line for periods of five hours or longer.

Clinical outcomes of a veterans affairs outpatient antimicrobial treatment program.

OBJECTIVES: The outpatient parenteral antibiotic therapy (OPAT) program of the Portland Veterans Affairs Medical Center (PVAMC), which has a self-administration model, is staffed by visiting nurses from a specialist infusion company. This study evaluates the clinical outcomes of these patients. METHODS: This study was a retrospective chart review of 262 patients at PVAMC who had received OPAT between 2007 and 2009. Patients were included only if they received ongoing care at PVAMC. The data collected included conditions and organisms being treated and types and durations of antibiotics used. Clinical cure was defined as documented cure at the end of treatment and 90 days post-OPAT. RESULTS: One hundred ninety patients of 262 were analyzed. The mean age was 63.2 years. Diabetes was the main comorbid factor (17%). The most common indications for OPAT were osteomyelitis (38%), urinary tract infection (23%), and skin and soft tissue infection (12.6%). Mixed bacterial culture (26%) and Staphylococcus aureus (31%) were the most common organisms treated. Vancomycin was the most frequently used antibiotic (26%) followed by ceftriaxone (12%). The median duration of OPAT was 30 days. The rate of clinical cure at end of treatment observed for all infections treated was 78%, which then decreased to 58% at 90 days post-OPAT (P < 0.001). Patients with diabetes and osteomyelitis had an increased risk of relapse at 90 days post-OPAT on multivariate analysis (P = 0.025). CONCLUSIONS: An OPAT program using a self-administration model treating patients who were military veterans had successful outcomes. Patients with diabetes and osteomyelitis had worse clinical outcomes 90 days after the completion of OPAT therapy.

Comparative effectiveness of nafcillin or cefazolin versus vancomycin in methicillin-susceptible Staphylococcus aureus bacteremia.

BACKGROUND: The high prevalence of methicillin-resistant S. aureus (MRSA) has led clinicians to select antibiotics that have coverage against MRSA, usually vancomycin, for empiric therapy for suspected staphylococcal infections. Clinicians often continue vancomycin started empirically even when methicillin-susceptible S. aureus (MSSA) strains are identified by culture. However, vancomycin has been associated with poor outcomes such as nephrotoxicity, persistent bacteremia and treatment failure. The objective of this study was to compare the effectiveness of vancomycin versus the beta-lactam antibiotics nafcillin and cefazolin among patients with MSSA bacteremia. The outcome of interest for this study was 30-day in-hospital mortality. METHODS: This retrospective cohort study included all adult in-patients admitted to a tertiary-care facility between January 1, 2003 and June 30, 2007 who had a positive blood culture for MSSA and received nafcillin, cefazolin or vancomycin. Cox proportional hazard models were used to assess independent mortality hazards comparing nafcillin or cefazolin versus vancomycin. Similar methods were used to estimate the survival benefits of switching from vancomycin to nafcillin or cefazolin versus leaving patients on vancomycin. Each model included statistical adjustment using propensity scores which contained variables associated with an increased propensity to receive vancomycin. RESULTS: 267 patients were included; 14% (38/267) received nafcillin or cefazolin, 51% (135/267) received both vancomycin and either nafcillin or cefazolin, and 35% (94/267) received vancomycin. Thirty (11%) died within 30 days. Those receiving nafcillin or cefazolin had 79% lower mortality hazards compared with those who received vancomycin alone (adjusted hazard ratio (HR): 0.21; 95% confidence interval (CI): 0.09, 0.47). Among the 122 patients who initially received vancomycin empirically, those who were switched to nafcillin or cefazolin (66/122) had 69% lower mortality hazards (adjusted HR: 0.31; 95% CI: 0.10, 0.95) compared to those who remained on vancomycin. CONCLUSIONS: Receipt of nafcillin or cefazolin was protective against mortality compared to vancomycin even when therapy was altered after culture results identified MSSA. Convenience of vancomycin dosing may not outweigh the potential benefits of nafcillin or cefazolin in the treatment of MSSA bacteremia.

Poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid): synthesis, physico-chemical characterisation and nafcillin carrier.

In the present study polymeric microbeads of poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid) or p(HEMA-co-dDMA-co-AA) were synthesised and characterized through FT-IR and scanning electron microscopy (SEM); their swelling behavior against saline solution was explored and their in vitro cytotoxicity was evaluated. Further, in order to elucidate kinetic aspects regarding the ternary system p(HEMA-co-dDMA-co-AA), a mathematical model of the reactivity ratios of the comonomers in the terpolymer has been conceived and analyzed. An intensified tendency of AA units accumulation in the copolymer has been noticed, in spite of HEMA units, while dDMA conserves in the copolymer the fraction from the feed. Three compositions have been selected for nafcillin-loading and their in vitro release capacity was evaluated. The compositions of 80:10:10 and 75:10:15 M ratios appear suitable for further in vivo testing, in order to be used as drug delivery systems in the treatment of different osseous diseases.

Subinhibitory concentrations of tedizolid potently inhibit extracellular toxin production by methicillin-sensitive and methicillin-resistant Staphylococcus aureus.

PURPOSE: Potent extracellular toxins including alpha-haemolysin, Panton-Valentine leukocidin (PVL) and toxic-shock syndrome toxin 1 (TSST-1) significantly contribute to Staphylococcus aureus pathogenesis, thus, toxin suppression is a primary focus in treatment of staphylococcal disease. S. aureus maintains complex strategies to regulate toxin expression and previous data have demonstrated that subinhibitory concentrations of beta-lactam antibiotics can adversely increase S. aureus exotoxin production. The current study evaluates the effects of subinhibitory concentrations of tedizolid, a second-generation oxazolidinone derivative, on expression of staphylococcal exotoxins in both methicillin-resistant and methicillin-sensitive S. aureus. METHODOLOGY: S. aureus exotoxin expression levels were compared at 12 and 24 h following treatment with tedizolid, linezolid, nafcillin or vehicle control. RESULTS: Our findings show that the level of antibiotic required to alter toxin production was strain-dependent and corresponds with the quantity of toxin produced, but both tedizolid and linezolid could effectively reduce expression of alpha-haemolysin, PVL and TSST-1 toxin at subinhibitory concentrations. In contrast, nafcillin showed less attenuation and, in some S. aureus strains, led to an increase in toxin expression. Tedizolid consistently inhibited toxin production at a lower overall drug concentration than comparator agents. CONCLUSION: Together, our data support that tedizolid has the potential to improve outcomes of infection due to its superior ability to inhibit S. aureus growth and attenuate exotoxin production.

Comparative outcomes of cefazolin versus nafcillin for methicillin-susceptible Staphylococcus aureus bacteraemia: a prospective multicentre cohort study in Korea.

OBJECTIVES: No randomized controlled trials have evaluated the comparative outcomes of cefazolin versus nafcillin for methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia. METHODS: A prospective observational cohort study including all S. aureus bacteraemia was conducted at 10 hospitals. Patients (≥15 years) with MSSA bacteraemia who received cefazolin or nafcillin as definitive antibiotics were included. The rates of treatment failure (premature discontinuation of antibiotics because of adverse effects, switching of antibiotics because of clinical failure, all-cause mortality within 1 month, or recurrence) were compared between the cefazolin and nafcillin groups. Propensity score matching analyses were performed to balance the factors influencing the selection of antibiotics. RESULTS: Among the 242 included cases, the bones and joints (36.8%) were the most common sites of infection and 60.7% of the patients had sepsis. The overall treatment failure rate was 43.8% (106/242). All-cause mortality within 1 month was 6.2% (15/242). After propensity score matching, the treatment failure rate of cefazolin was lower than that of nafcillin (30.4% (24/79) vs. 49.4% (39/79), p 0.015) because of a higher rate of discontinuation caused by adverse events. When the data were limited to patients with sepsis, the treatment failure rates of both groups were not significantly different. Approximately 22% (24/110) of MSSA isolates exhibited a cefazolin-inoculum effect (CIE) that had significant impact on the failure rate and mortality of the cefazolin group. CONCLUSIONS: Cefazolin might be recommended as an adequate and better-tolerated treatment for MSSA bacteraemia in the absence of CIE.

Vancomycin associated acute kidney injury in pediatric patients.

INTRODUCTION: Vancomycin associated acute kidney injury (vAKI) is a well known complication in pediatric patients. Identification and characterization of the incidence and risk factors for vAKI in the pediatric population would assist clinicians in potentially preventing or mitigating vAKI. METHODS AND MATERIALS: A 6 year retrospective cohort study was designed. Patients were included if they were < 19 years of age, received vancomycin as inpatients, and had a baseline SCr and one other SCr drawn during and up to 72 hours after the discontinuation of vancomycin. Data collection included patient demographics, vancomycin doses and length of therapy, vancomycin serum concentrations, and concomitant medications. The Kidney Disease Improving Global Outcomes (KDIGO) criteria were used to characterize acute kidney injury. Descriptive statistical methods were used and ordinal logistic regression was employed to determine variables significantly associated with vAKI. RESULTS: A total of 7,095 patients met study criteria (55.4% male, median age 4.1 years (IQR 0.67-11.2 years)). Mechanical ventilation was used in 7.9% (n = 563) and mortality was 4.9% (n = 344). A total of 153 concomitant medications were identified. A median of 5 (IQR 3-7) SCr values were obtained and median SCr prior to vancomycin was 0.39 (IQR 0.28-0.57) mg/dL (CrCl 134±58 mL/min/1.73m2). Vancomycin was administered for a median of 2 (IQR 1-3) days (14.9±1.6 mg/kg/dose). vAKI was present in 12.2% (n = 862: KDIGO stage 1 (8.30%, n = 589), KDIGO stage 2 (1.94%, n = 138) KDIGO stage 3 (1.89%, n = 134)). Mean vancomycin serum concentration at 6-8 hours after a dose for patients with vAKI (10.7±8.9 mg/L) was significantly, but not clinically different for patients with no vAKI (7.5±6.3 mg/L). (p<0.05) Ordinal logistic regression identified total dose of vancomycin, vancomycin administration in the intensive care unit, and concomitant medication administration as significant for vAKI. In particular, concomitant administration of several different medications, including nafcillin, clindamycin, and acetazolamide, were noted for strong associations with vAKI. (p<0.05). CONCLUSIONS: Moderate to severe acute kidney injury due to vancomycin is infrequent in children and associated with concomitant medication use and total dose of vancomycin. Serum vancomycin concentrations are not useful predictors of vAKI in the pediatric population.

Nafcillin versus cefazolin for the treatment of methicillin-susceptible Staphylococcus aureus bacteremia.

BACKGROUND: Anti-staphylococcal penicillins have long been the first-line treatment option for methicillin-susceptible Staphylococcus aureus (MSSA) infections. Recent retrospective data comparing nafcillin and cefazolin report similar clinical efficacy despite concerns about high inoculum MSSA infections. METHODS: This was a retrospective, non-inferiority, cohort study comparing treatment failure rates between nafcillin and cefazolin in patients with MSSA bacteremia from any source, other than meningitis. Multiple logistic regression was used to adjust for confounding variables. RESULTS: A total of 142 patients were included in the study. The overall treatment failure rate among patients receiving cefazolin was non-inferior to nafcillin (11.3% versus 8.5%; 90% confidence interval -5.2% to 10.8%). Rates of adverse drug events were significantly higher in the nafcillin arm (19.7% versus 7%; p=0.046). After adjustment for confounding variables, no difference between treatment groups was found in treatment failure (adjusted odds ratio (OR)=1.2; 95% CI, 0.3-4.5), but nafcillin was associated with significantly higher nephrotoxicity (adjusted odds ratio (OR)=5.4; 95% CI, 1.1-26.8). CONCLUSION: Cefazolin was associated with lower nephrotoxicity and similar treatment failure rates compared to nafcillin suggesting that cefazolin is an appealing first line agent for most MSSA bloodstream infections.

Interaction between warfarin and nafcillin: case report and review of the literature.

A 39-year-old man with a history of deep vein thrombosis and septic arthritis of the left knee was treated with warfarin and cefazolin. Therapeutic prothrombin times and international normalized ratios (INRs) were maintained with warfarin 32 mg/week for approximately 1 month. When the patient's antibiotic regimen was changed from cefazolin to nafcillin 2 g every 4 hours, his INR declined significantly. His warfarin dosage had to be increased to a maximum of 88 mg/week to achieve a therapeutic INR. After completion of antibiotic therapy with nafcillin, the patient's warfarin requirements slowly declined over several weeks. A maintenance dosage of warfarin 42-48 mg/week was necessary after nafcillin discontinuation. Hepatic cytochrome P450 isoenzyme induction by nafcillin is likely the mechanism of a warfarin-nafcillin interaction. The usual onset of effect is within 1 week after starting nafcillin, and the offset of the effect is usually evident within 4 weeks after nafcillin discontinuation. In patients taking warfarin who are prescribed nafcillin, a 2-4-fold increase in the warfarin dose may be necessary, and clinicians should closely monitor INRs.

Sternoclavicular Osteomyelitis in an Immunosuppressed Patient: A Case Report and Review of the Literature.

BACKGROUND Sternoclavicular osteomyelitis is a rare disease, with less than 250 cases identified in the past 50 years. We present a rare case of sternoclavicular osteomyelitis in an immunosuppressed patient that developed from a conservatively treated dislocation. CASE REPORT A 62-year-old white man with a history of metastatic renal cell carcinoma presented to the emergency department (ED) with a dislocated left sternoclavicular joint. He was managed conservatively and subsequently discharged. However, over subsequent days he began to experience pain, fever, chills, and night sweats. He presented to the ED again and imaging revealed osteomyelitis. In the operating room, the wound was aggressively debrided and a wound vac (vacuum-assisted closure) was placed. He was diagnosed with sternoclavicular osteomyelitis and placed on a 6-week course of intravenous Nafcillin. CONCLUSIONS Chemotherapy patients who sustain joint trauma normally associated with a low risk of infection should be monitored thoroughly, and the option to discontinue immunosuppressive therapy should be considered if signs of infection develop.

Catastrophic chest pain: blinded by cardiopulmonary disease.

A 53-year-old man with a history of diabetic foot ulcer, osteomyelitis, coronary artery disease, hypertension and hyperlipidaemia, presented with chest pain of 3 weeks duration. Eleven days earlier, the patient had had a drug-eluting stent (DES) placed in a branch of the right coronary artery (RCA) after similar chest pain, leading to the findings of a positive nuclear stress test. Since discharge, he was not compliant with taking clopidegrel (Plavix), a concern for in-stent thrombosis with recurrent myocardial ischaemia; but work up was negative and medications were restarted. Within 24 h of admission, he developed bilateral flaccid leg weakness, urine retention and loss of sensation from the umbilicus level down. MRI revealed a T4-T6 epidural abscess. Emergent decompression laminectomy and abscess drainage was completed. Neurological symptoms improved hours after surgery with complete resolution of sensory deficits. Cultures grew Streptococcus sp., treated with intravenous nafcillin for 8 weeks. He regained leg strength with continued improvement seen in rehabilitation.

Meningitis due to Staphylococcus aureus.

A retrospective analysis of 10 adult patients with community-acquired Staphylococcus aureus meningitis was performed in order to elucidate the characteristics and treatment of this lethal disease. In all patients, a focus of infection outside the central nervous system was apparent at presentation. A poor prognosis was associated with severe underlying disease, greater degree of hyponatremia at presentation, development of seizures, failure of nuchal rigidity to develop, persistent or recurrent bacteremia, and the presence of concurrent S. aureus bronchopneumonia. Degree of deterioration in mental status and cerebrospinal fluid pleocytosis, protein levels, and glucose levels did not appear to have any prognostic significance. Therapy with rifampin and a semisynthetic penicillin effected a cure in all six patients treated with this regimen. In contrast, three of four patients treated with other antibiotic combinations died. On the basis of this experience, it is concluded that further trials with rifampin in combination with another anti-staphylococcal antibiotic for the treatment of S. aureus meningitis are warranted.

Metastatic intracranial abscesses of bronchopulmonary origin.

Intracranialabscesses are serious, life-threatening infections despite recent advances in diagnosis and treatment. We report the case of a child with metastatic brain abscesses and a chronic, sharp foreign body of the bronchus. Its presentation and endoscopic appearance and the microbiology of the abscesses are detailed. The detection of bacteria of respiratory origin should lead to a search for a bronchopulmonary source of contamination.

Use of systemic antibiotics for prophylaxis in surgery: a critical review.

We reviewed the English-language literature over a 16-year period (1960 through 1976) on the subject of prophylaxis with systemic antibiotics in surgery. Trials in genitourinary and cardiovascular surgery were not reviewed. Our definition of prophylaxis is antibiotic administration of the absence of infection or contamination. Of 131 articles reporting clinical trials using systemic antibiotics for prophylaxis, only 24 met the criterion on an appropriately designed study that generated evaluable data. In these, systemic antibiotics were shown to be of value in reducing wound infections after abdominal and vaginal hysterectomy, cesarean section, biliary surgery, total hip replacement, and microneurosurgical craniotomy. Antibiotic prophylaxis was of no value in laparotomy and groin hernia repair. Patients undergoing any of 21 different operations did not benefit from prophylactic antibiotic administration, though study groups were too small or infection rates too low to allow for firm conclusions. In certain patients at high risk of infection, systemic prophylaxis is warranted. Future clinical studies must be designed as randomized, blinded, prospective trials, with antibiotics administered by a parenteral route beginning preoperatively.

The effect of probenecid on nafcillin disposition.

Five normal male volunteers participated in an open crossover study designed to examine the disposition of nafcillin given intravenously with and without probenecid. Each subject received two 500 mg iv doses of sodium nafcillin seven days apart, one dose without probenecid and another dose during oral probenecid administration of 1.0 Gm at bedtime prior to the study day and 1.0 Gm two hours before the nafcillin dose. Blood and urine samples were collected for 10 hours after nafcillin dosing. Assay for nafcillin concentrations was performed via the cup-plate technique with M. luteus. Administration of probenecid significantly increased and prolonged circulating plasma concentrations of nafcillin. Probenecid administration significantly, decreased the per cent of nafcillin recovered in the urine (30% vs. 16.9%). Probenecid pretreatment increased the ana under the plasma drug concentration-time curve (AUC) two-fold and decreased the total body clearance significantly with decreases in both renal and non-renal clearance. K12/k21 and Vc did not significantly change with probenecid. Because probenecid coadministration did not appear to change nafcillin distribution while increasing and prolonging plasma concentrations, probenecid can be recommended to be given concurrently when high nafcillin plasma concentrations are desirable. Changes in plasma concentrations are apparently due to alterations in both renal and non-renal clearances of nafcillin.