Haluk Eraksoy

Spread of OXA-48-Positive Carbapenem-Resistant Klebsiella pneumoniae Isolates in Istanbul, Turkey

ABSTRACT The first outbreak of carbapenem-resistant Klebsiella pneumoniae isolates producing the plasmid-encoded carbapenem-hydrolyzing oxacillinase OXA-48 is reported. The 39 isolates belonged to two different clones and were collected at the University Hospital of Istanbul, Turkey, from May 2006 to February 2007, and they coproduced various β-lactamases (SHV-12, OXA-9, and TEM-1 for clone A and CTX-M-15, TEM-1, and OXA-1 for clone B).

Effect of magnesium sulfate administration on blood-brain barrier in a rat model of intraperitoneal sepsis: a randomized controlled experimental study.

IntroductionPermeability changes in the blood–brain barrier (BBB) and their possible contribution to brain edema formation have a crucial role in the pathophysiology of septic encephalopathy. Magnesium sulfate has been shown to have a protective effect on BBB integrity in multiple experimental models. In this study we determine whether magnesium sulfate administration could have any protective effects on BBB derangement in a rat model of sepsis.MethodsThis randomized controlled experimental study was performed on adult male Sprague–Dawley rats. Intraperitoneal sepsis was induced by using the infected fibrin–thrombin clot model. To examine the effect of magnesium in septic and sham-operated rats, a dose of 750 μmol/kg magnesium sulfate was given intramuscularly immediately after surgery. Control groups for both infected and sham-operated rats were injected with equal volume of saline. Those rats surviving for 24 hours were anesthetized and decapitated for the investigation of brain tissue specific gravity and BBB integrity by the spectrophotometric assay of Evans blue dye extravasations. Another set of experiments was performed for hemodynamic measurements and plasma magnesium level analysis. Rats were allocated into four parallel groups undergoing identical procedures.ResultsSepsis significantly increased BBB permeability to Evans blue. The dye content of each hemisphere was significantly lower in the magnesium-treated septic rats (left hemisphere, 0.00218 ± 0.0005; right hemisphere, 0.00199 ± 0.0007 [all results are means ± standard deviation]) than in control septic animals (left hemisphere, 0.00466 ± 0.0002; right hemisphere, 0.00641 ± 0.0003). In septic animals treated with magnesium sulfate, specific gravity was higher (left hemisphere, 1.0438 ± 0.0007; right hemisphere, 1.0439 ± 0.0004) than in the untreated septic animals (left hemisphere, 1.0429 ± 0.0009; right hemisphere, 1.0424 ± 0.0012), indicating less edema formation with the administration of magnesium. A significant decrease in plasma magnesium levels was observed 24 hours after the induction of sepsis. The dose of magnesium that we used maintained the baseline plasma magnesium levels in magnesium-treated septic rats.ConclusionsMagnesium administration attenuated the increased BBB permeability defect and caused a reduction in brain edema formation in our rat model of intraperitoneal sepsis.

Comparative Activities of β-Lactam Antibiotics and Quinolones for Invasive Streptococcus pneumoniae Isolates

Background: Streptococcus pneumoniae is a leading pathogen causing pneumonia, meningitis, otitis media, bacteremia and sinusitis resulting in significant morbidity and mortality. We examined in vitro activities of five quinolones in comparison with other antibiotics against 85 invasive pneumococcal isolates. Methods: Minimal inhibitory concentrations (MICs) of penicillin G, cefuroxime, azithromycin, clarithromycin, trimethoprim-sulfamethoxazole (SXT), ciprofloxacin, ofloxacin, levofloxacin, trovafloxacin and gemifloxacin were determined using a broth microdilution method. Results: The overall rates of resistance to penicillin (46%), cefuroxime (20%), azithromycin (20%), clarithromycin (18%) and SXT (46%) were considerable. Among all of the isolates, 9 isolates (11%) were highly resistant (MIC ≧2 mg/l) and 30 isolates (35%) had intermediate resistance (MIC 0.12– 1.0 mg/l). Of the quinolones gemifloxacin and trovafloxacin had the highest activity. The penicillin resistance status of the isolates did not have any effect on the resistance pattern of new quinolones. Conclusion: The new quinolones show great potential in the treatment of invasive infections caused by both penicillin-susceptible and penicillin-resistant pneumococci.

Central venous catheter related infections: Risk factors and the effect of glycopeptide antibiotics

BackroundWe undertook a prospective study of all new central venous catheters inserted into patients in the intensive care units, in order to identify the risk factors and to determine the effect of glycopeptide antibiotics on catheter – related infections.MethodsDuring the study period 300 patients with central venous catheters were prospectively studied. The catheters used were nontunneled, noncuffed, triple lumen and made of polyurethane material. Catheters were cultured by semiquantitative method and blood cultures done when indicated. Data were obtained on patient age, gender, unit, primary diagnosis on admission, catheter insertion site, duration of catheterization, whether it was the first or a subsequent catheter and glycopeptide antibiotic usage.ResultsNinety-one (30.3%) of the catheters were colonized and infection was found with 50 (16.7%) catheters. Infection was diagnosed with higher rate in catheters inserted via jugular vein in comparison with subclavian vein (95% CI: 1.32–4.81, p = 0.005). The incidence of infection was higher in catheters which were kept in place for more than seven days (95% CI 1.05–3.87, p = 0.03). The incidence of infection was lower in patients who were using glycopeptide antibiotic during catheterization (95% CI: 1.49–5.51, p = 0.005). The rate of infection with Gram positive cocci was significantly lower in glycopeptide antibiotic using patients (p = 0.01). The most commonly isolated organism was Staphylococcus aureus (n = 52, 37.1%).ConclusionDuration of catheterization and catheter insertion site were independent risk factors for catheter related infection. Use of glycopeptide antibiotic during catheterization seems to have protective effect against catheter related infection.

Rhinocerebral mucormycosis treated with 32 gram liposomal amphotericin B and incomplete surgery: a case report

BackgroundMucormycosis (or zygomycosis) is the term for infection caused by fungi of the order Mucorales. Mucoraceae may produce severe disease in susceptible individuals, notably patients with diabetes and leukemia. Rhinocerebral mucormycosis most commonly manifests itself in the setting of poorly controlled diabetes, especially with ketoacidosis.Case PresentationA 31-year-old diabetic man presented to the outpatient clinic with the following signs and symptoms: headache, periorbital pain, swelling and loss of vision in the right eye. On physical examination his right eye was red and swollen. There was periorbital cellulitis and the conjunctiva was edematous. KOH preparation of purulent discharge showed broad, ribbonlike, aseptate hyphae when examined under a fluorescence microscope. Cranial MRI showed involvement of the right orbit, thrombosis in cavernous sinus and infiltrates at ethmoid and maxillary sinuses. Mucormycosis was diagnosed based on these findings. Amphotericin B (AmBisome®; 2 mg/kg.d) was initiated after the test doses. Right orbitectomy and right partial maxillectomy were performed; the lesions in ethmoid and maxillary sinuses were removed. The duration of the liposomal amphotericin B therapy was approximately 6 months and the total dose of liposomal amphotericin B used was 32 grams. Liposomal amphotericin B therapy was stopped six months later and oral fluconazole was started.ConclusionsAlthough a total surgical debridement of the lesions could not be performed, it is remarkable that regression of the disease could be achieved with medical therapy alone.

Extrapulmonary tuberculosis in immunocompetent adults

Tuberculosis continues to be a significant cause of morbidity and mortality. Although tuberculosis usually attacks the lungs, other organs can also be affected, leading to extrapulmonary tuberculosis (EPT) or disseminated tuberculosis. This study retrospectively analysed the incidence, clinical sites and risk factors for EPT in 252 patients with EPT between 1 January 1991 and 30 June 2003. EPT was defined as clinical, laboratory, imaging, and/or histopathological evidence of mycobacterial infection in a site other than hilar lymph nodes or lung parenchyma. In our study group, tuberculous lymphadenitis (36.5%) was found to be the most common clinical presentation of EPT. 119 (47.2%) patients developed the severe form of EPT, according to the WHO report, and 133 (52.8%) patients developed the less severe form. A case history of pulmonary tuberculosis was found to be a risk factor for the development of EPT (p<0.05). The study showed that EPT is still a public health problem. These findings suggested that pulmonary tuberculosis may play a critical role in the development of EPT. 12-month therapy may be chosen in patients with EPT considering acceptable adverse effects without relapses.

Immunization of renal transplant recipients with pneumococcal polysaccharide vaccine

Background: Streptococcus pneumoniae, a common pathogen leading to pneumonia, is a cause of morbidity and mortality in immunosuppressed patients. Vaccination against this agent can be recommended for immunosuppressed patients, including those with chronic renal failure, nephrotic syndrome and renal transplant recipients; however, a diminished immune response and loss of protective antibodies have been observed.Patients and methods: In our prospective study, the efficacy and side effects of polyvalent pneumococcal vaccination were investigated in renal transplant recipients. A total of 21 patients (6 female, 15 male) with well‐functioning renal allografts, who had transplant surgery at least 2 months before, were included in the study. The patients were stratified according to the immunosuppressive protocol and 8 received double, while 13 received triple, immunosuppresive agents. After obtaining basal serum samples, all cases were vaccinated with the 0.5 mL intramuscular administration of polyvalent polysaccharide pneumococcal vaccine (Pneumo 23 Pasteur–Merieux, lot No: K 1131).Results: Following a mean of 6 wk in all patients and also a mean of 12 wk in 12 patients, serum samples were again obtained to measure pneumococcal antibodies. Antibody titers following 6 and 12 wk of vaccination were significantly higher, as compared with basal values in all patients, except one. These titers did not show any statistically significant difference between double and triple therapies. There was no significant difference between the 12th and 6th wk postvaccination antibody titers. No systemic or local adverse effects were observed.Conclusion: Pneumococcal vaccination is safe and effective in patients with well‐functioning renal allografts, at least in the short term. This vaccination policy may be useful for preventing invasive pneumococcal disease in immunosuppressed patients.

Comparative activity of carbapenem testing: the COMPACT study

OBJECTIVES Doripenem is a new carbapenem recently introduced into Europe. The COMParative Activity of Carbapenem Testing (COMPACT) study compared the susceptibility of common Gram-negative bacilli causing serious infections in hospitalized patients with doripenem, imipenem and meropenem. METHODS Gram-negative isolates (4498 total: 2171 Pseudomonas species; 1910 Enterobacteriaceae; and 417 other Gram-negative bacilli) were collected from 80 centres in 16 countries in Europe, the Middle East and Africa during 2008-09. The MICs of doripenem, imipenem and meropenem were determined using Etest methodology and broth microdilution. Susceptibility was interpreted according to CLSI, EUCAST and FDA breakpoints. RESULTS The MIC(90)s of doripenem, imipenem and meropenem for all isolates were 8, ≥64 and 32 mg/L, respectively. Doripenem had the lowest MIC(90) for Pseudomonas species at 16 mg/L, with imipenem and meropenem values of ≥64 mg/L. Enterobacteriaceae were highly susceptible to all three carbapenems, with MIC(90)s of doripenem, imipenem and meropenem of 0.06, 0.5 and 0.12 mg/L, respectively. Other Gram-negative isolates, predominantly Acinetobacter baumannii, were resistant to all three carbapenems (MIC(90) ≥64 mg/L). Susceptibility to doripenem was observed in 14.9% of isolates resistant to imipenem and/or meropenem. CONCLUSIONS Doripenem showed excellent activity against Gram-negative isolates; generally it was more active than imipenem and at least as good as meropenem. Against Pseudomonas species, doripenem was more active than both imipenem and meropenem, with doripenem susceptibility observed for some imipenem- and/or meropenem-resistant isolates.

Stereotactic surgery in the management of brain abscess

BACKGROUND Bacterial brain abscesses can be diagnosed and treated with stereotactic aspiration. METHODS From 1991 to 1997 we have used computed tomography-guided stereotactic aspiration to diagnose and treat 21 patients with a total of 58 bacterial brain abscesses. The ages of the patients ranged from 4 to 72 years (median 25 years); 11 of these 21 patients had multiple abscesses. The number of abscesses per patient with multiple abscesses ranged from 2 to 9, all located deep in subcortical white matter. RESULTS All patients underwent stereotactic surgical drainage and an 8-week intravenous antibiotic medical treatment. Of the 58 abscesses, 23 were aspirated. Of these 23 abscesses, 19 were radiologically stage III or IV and four were stage I or II. Pathological examination confirmed radiological staging in 19 patients (83%). Except for the three patients who have mild residual hemiparesis and one patient recovering from ataxia, all patients had complete neurological recovery. CONCLUSIONS Computed tomography-guided stereotaxy achieved all the objectives of management; namely, ascertaining the diagnosis, draining the content of the mass, and obtaining pus for accurate bacteriological diagnosis without morbidity. Stereotactic aspiration combined with an 8-week intravenous antibiotic regimen has yielded an effective therapeutic result in all of our abscesses, small or large, solitary or multiple, superficial or deep-seated. A high radiological-pathological correlation was also deduced from this study.

Immune response to Haemophilus influenzae type b vaccination in renal transplant recipients with well-functioning allografts

Background: Haemophilus influenzae infection is a mild and self-limited disease in the healthy population. However, it may show an aggressive course in the immunocompromised state which underlines the importance of vaccination against this agent. On the other hand, posttranplant immunosuppression may impair immune responses and thus the efficacy of the vaccination. Methods: Forty-three renal transplant recipients with well-functioning allografts were immunized with H. influenzae type b vaccine in order to investigate the immune response. The patients received a double or a triple immunosuppressive protocol. Seven healthy members of the dialysis unit served as controls. After obtaining basal serum samples, the patients and the control subjects were immunized with H. influenzae type b conjugate vaccine. After 6 and 12 weeks, serum samples obtained again to determine H. influenzae type b antibody titers. Results: The antibody titers 6 and 12 weeks after vaccination were significantly higher as compared with the basal values, similar to those of the control subjects. These titers did not show statistically significant differences between the double and triple immunosuppressive therapy groups. After 12 weeks of vaccination, the antibody titers did not show a statistically significant difference as compared with those obtained after 6 weeks. Conclusion: H. influenzae type b vaccination is safe and effective in patients with well-functioning renal allografts and should be recommended to renal transplant recipients who may have the risk of invasive disease on the basis of the immunosuppressive state.