Nafcillin degradation by heterogeneous electro-Fenton process using Fe, Cu and Fe/Cu nanoparticles.

Heterogeneous electro-Fenton (HEF) is as an alternative to the conventional electro-Fenton (EF) process. HEF uses a solid phase catalyst, whereas EF employs a solubilized one. This implies that in HEF, material can be recovered through a simple separation process such as filtration or magnetic separation in HEF. HEF also has the advantage of not requires a previous pH adjustment, which facilitates working in a higher pH range. In this work, Fe, Cu and Fe/Cu bimetallic nanoparticles (Fe/Cu NPs) were synthesized, characterized and used for the degradation of Nafcillin (NAF). The effect of the adsorption and the anodic oxidation (AO-H2O2) process was tested to assess their influence on HEF. NAF adsorption did not exceed 24% of antibiotic removal and the AO-H2O2 process eliminated the total NAF after 240 min of electrolysis. Through the HEF process, the antibiotic was completely removed using Fe/Cu NPs after 7.0 min of electrolysis, while these NPs, mineralization reached 41% after 240 min. In this case, NAF degradation occurs mainly due to the generation of hydroxyl radicals in the BDD electrode, and the Fenton reaction with Fe and Cu NPs. The main organic intermediates produced during the degradation of NAF by HEF were identified allowing the proposal of degradation pathway. Finally, the antibiotic was also completely eliminated from a wastewater from slaughterhouse after 15 min of treatment by HEF and using Fe/Cu bimetallic NPs.

A comparison of safety and outcomes with cefazolin versus nafcillin for methicillin-susceptible Staphylococcus aureus bloodstream infections.

BACKGROUND: Methicillin-susceptible Staphylococcus aureus (MSSA) is a frequent cause of bloodstream infections (BSI). Treatment with nafcillin (NAF) has been preferred to cefazolin (CFZ). However, comparable outcomes have been found with CFZ with possibly lower risk for side-effects. This study compared safety and effectiveness of NAF versus CFZ for MSSA BSI. METHODS: This single center retrospective study evaluated adults admitted with MSSA BSI who received NAF or CFZ. Patients receiving ≥24 h of antibiotics were included for safety analyses. Patients receiving NAF or CFZ for ≥75% of a 14 day minimum treatment course were assessed for clinical effectiveness. The primary safety outcome was incidence of renal toxicity with multiple secondary safety endpoints. Clinical success was defined as symptom resolution, repeat negative cultures, lack of additional therapy for presumed failure, and lack of recurrence within 30 days. RESULTS: A total of 130 patients receiving NAF (n = 79) or CFZ (n = 51) were included for safety analysis. Of those, 90 met criteria for effectiveness assessment (NAF n = 40, CFZ n = 50). Baseline characteristics were well matched. NAF was associated with a higher incidence of nephrotoxicity compared to CFZ (25% vs. 2%, RR 1.31, 95% CI 1.15-1.5, p < 0.001), allergic reactions (p = 0.01) and a trend for hepatotoxicity (p = 0.08). Clinical success was achieved in 82% NAF and 94% CFZ treated patients (p = 0.1). CONCLUSION: CFZ was associated with less nephrotoxicity and no difference in clinical success compared to NAF for MSSA BSI. A prospective study comparing NAF to CFZ for MSSA BSI should be conducted to elucidate differences in therapies.

Septic arthritis of native hip joint by Staphylococcus lugdunensis: a case report.

Staphylococcus lugdunensis is a rare virulent coagulase-negative staphylococcus (CoNS) that behaves similarly to Staphylococcus aureus in causing deep abscesses, skin and soft tissue infections, and central nervous system infections. Additionally, there can be certain blood stream infections including sepsis, septic shock, toxic shock syndrome, and endocarditis complicated by embolic events. Reports of septic arthritis of a native joint associated with this organism have been infrequent, justifying the presentation and discussion of this case.

Septic arthritis of native hip joint by Staphylococcus lugdunensis: a case report

Abstract Staphylococcus lugdunensis is a rare virulent coagulase-negative staphylococcus (CoNS) that behaves similarly to Staphylococcus aureus in causing deep abscesses, skin and soft tissue infections, and central nervous system infections. Additionally, there can be certain blood stream infections including sepsis, septic shock, toxic shock syndrome, and endocarditis complicated by embolic events. Reports of septic arthritis of a native joint associated with this organism have been infrequent, justifying the presentation and discussion of this case.

Effective removal of the antibiotic Nafcillin from water by combining the Photoelectro-Fenton process and Anaerobic Biological Digestion.

The elimination of the antibiotic Nafcillin (NAF), which is usually used in hospitals and veterinary clinics around the world, was assessed through a combination of three advanced electrochemical oxidation processes followed by anaerobic digestion process. In the first stage different electrochemical advanced oxidation processes (EAOPs) were used: electro-oxidation with hydrogen peroxide (EO-H2O2), electro-Fenton (EF) and Photo electro-Fenton (PEF). After PEF, almost complete and highly efficient degradation and elimination of NAF was achieved, with the concomitant elimination of the associated antimicrobial activity. The fast degradation rate produced by PEF is explained by the oxidative action of hydroxyl radicals (•OH) together with the direct UV photolysis of complexes formed between Fe3+ and some organic intermediates. Total removal of NAF occurs after 90min of electrolysis by PEF, with the generation of organic intermediates that remain in solution. However, when this post PEF process solution was treated with an anaerobic biological process, the intermediates generated in the electrochemical degradation of NAF were completely eliminated after 24h. The kinetic degradation of NAF as well as the identification/quantification of products and intermediates formed during the degradation of antibiotic, such as inorganic ions, carboxylic acids and aromatic compounds, were determined by chromatographic and photometric methods. Finally, an oxidation pathway is proposed for the complete conversion to CO2.

Disseminated methicillin-susceptible Staphylococcus aureus infection.

INTRODUCTION: When clinicians think about Staphylococcus aureus bacteria, what comes to the mind of most is the dreaded methicillin-resistant form. However, clinicians should not forget the methicillin-susceptible type, which is just as virulent. CASE PRESENTATION: The authors present the case of a 20-year-old woman who was admitted with septic shock and multi-organ failure and was found to have disseminated methicillin-susceptible Staphylococcus aureus (MSSA) infection. The patient had persistent blood cultures positive for MSSA. A transesophageal echocardiogram showed a 1.1 cm vegetation in the mitral valve, and the patient had bilateral pleural effusions that grew MSSA. An MRI of the brain showed multiple areas consistent with infarctions thought to be secondary to septic emboli. The patient underwent a mitral valve replacement and was treated with a prolonged course of parenteral nafcillin. DISCUSSION: This case illustrates a severe clinical presentation and management of MSSA infections.

Rapidly Progressive Seeding of a Community Acquired Pathogen in an Immune-competent Host--End Organ Damage from Head to Bone.

This report describes a 64-years-old male patient that presented to our hospital with a chief complaint of acute worsening of his usual chronic lower back pain, progressive weakness in lower extremities and subjective fevers at home. Spine CT failed to demonstrate any infectious foci but showed partially visualized lung cavitary lesion and renal pole abnormalities. Blood cultures grew methicillin-sensitive Staphylococcus Aureus (MSSA). Transthoracic echocardiogram (TTE) showed no signs of infective endocarditis (IE). Later, the patient experienced an acute deterioration on clinical status and examination showed development of a new murmur. He also developed new hemiparesis with up-going babinski reflex. A head MRI showed multiple infarcts. MRI spine displayed osteomyelitis at T12-L1. Cerebro-spinal fluid was positive for meningitis. A transesophageal echocardiogram (TEE) was performed demonstrating new severe mitral and mild tricuspid regurgitations with a definitive 1.5 cm mobile vegetation on posterior mitral leaflet. We present is a very interesting case of a rapidly progressive MSSA infection. MSSA meningitis is a rare disease; there are only few reported cases in the literature to date. We describe a case of MSSA bacteremia, of questionable source, that resulted in MSSA endocarditis affecting right and left heart in a patient who did not have a history of intravenous drug use (IVDU) or immunosuppression. The case was complicated by septic emboli to systemic circulation involving the kidneys, vertebral spine (osteomyelitis), lungs and brain with consequent meningitis and stroke. Even when MSSA infections are well known, to our knowledge there are no previous case reports describing such an acute-simultaneous-manifestation of multi-end-organ failure, including meningitis and stroke. These latter are rarely reported, even individually.

Aztreonam in the treatment of soft tissue infections including diabetic foot infections

La eficacia y seguridad de aztreonam fue evaluada en 23 pacientes con infecciones agudas de tejido blando que incluían celulitis, úlceras, abscesos e infecciones de herida. Los pacientes recibieron las siguientes dosis endovenosas de aztreonam: 16 pacientes recibieron 1gm cada 8 horas, 5 pacientes recibieron 1gms cada 8 horas y 2 pacientes recibieron 0.5gm cada 8 horas. Una segunda droga fue administrada concomitantemente con aztreonam por vía endovenosa en la siguiente forma: 20 pacientes recibieron nafcilina 2gms cada 4 horas y 3 pacientes recibieron clindamicina 0.6gm cada 6 horas. La mayoría de los pacientes estaban seriamente enfermos con condiciones subyacentes como diabetes mellitus de un promedio de duración de 14 años (límites entre 2 y 40 años) en 19 de 23 pacientes (82%). Escherichia coli fue el organismo aislado más frecuentemente. La respuesta clínica demostró cura en 23/23 pacientes tratados. La respuesta bacteriológica demostró cura en 20/23 pacientes. Hubo 3 fallas bacteriológicas: la primera fue una superinfección con Pseudomonas maltophilia la segunda fue una pulmonía adquirida en el hospital y la tercera fue una superinfección con flora mixta (Enterococo, Staphylococcus aureus y Enterobacter aerogenes). No se documentaron efectos adversos serios. Aztreonam resultó ser un agente efectivo, seguro y valioso en el tratamiento de infecciones agudas de tejido blando causadas por bacilos aeróbicos gram-negativos susceptibles

Use of the serum bactericidal titer to assess the adequacy of oral antibiotic therapy in the treatment of acute hematogenous osteomyelitis.

Serum bactericidal titers against Staphylococcus aureus were measured in 63 children who were receiving mafcillin or methicillin intravenously, or dicloxacillin, penicillin, or cephalexin orally. The SBTs obtained following unit does of 25 mg/kg of dicloxacillin, 35 mg/kg of penicillin, or 25 mg/kg of cephalexin with probenecid were comparable to those seen following intravenous doses of 40 mg/kg nafcillin or methicillin. Twenty-two children with acute hematogenous osteomyelitis proven or presumed to be due to S. aureus were treated intravenously until point tenderness and fever had resolved, and then with oral therapy. The mean duration of intravenous therapy was 14 days. Oral doses were adjusted so that a peak SBT of greater than or equal to 1:16 and a trough SBT of greater than or equal to 1:2 were obtained in most children. No recurrences occurred. The SBT proved to be a practical means of assessing the adequacy of oral therapy in children with infections due to S. aureus.

Clinical and pharmacokinetic evaluation of nafcillin in infants and children.

Nafcillin (150 mg/kg/day, divided every six hours) was administered intravenously to 46 patients ranging from 5 to 163 months of age with suspected or proved bacterial infections. Thirteen of 15 patients with bacteriologically proved infection responded to nafcillin. Two patients with cellulitis due to Escherichia coli or to Hemophilus influenzae type b did not improve with nafcillin therapy. A mean serum nafcillin concentration of 48 microgram/ml was observed 30 minutes after a dose of 37.5 mg/kg. The mean serum half-life was 0.76 hours. There was no significant relation between age and serum half-life, volume of distribution, or plasma clearance rate. Two patients developed neutropenia and six other patients developed an eosinophilia greater than 400/mm3 while receiving nafcillin. No significant toxic effect of nafcillin on liver or renal function was observed. One patient had phlebitis. There was a significant correlation between nfacillin concentrations and serum inhibitory and bactericidal titers (P less than 0.001). Results from this study indicate that nafcillin is a safe and effective antibiotic for the treatment of infections due to susceptible bacteria in the dosage tested.

Disseminated Nocardia brasiliensis infection.

We report a 40-year-old man with advanced Hodgkin disease who received combination chemotherapy and developed disseminated Nocardia brasiliensis infection. We discuss opportunistic infections in the compromised host, with particular reference to nocardial disease and certain biologic characteristics of that organism.