Dissociable Contributions of Basolateral Amygdala and Ventrolateral Orbitofrontal Cortex to Flexible Learning Under Uncertainty.

Reversal learning measures the ability to form flexible associations between choice outcomes with stimuli and actions that precede them. This type of learning is thought to rely on several cortical and subcortical areas, including the highly interconnected orbitofrontal cortex (OFC) and basolateral amygdala (BLA), and is often impaired in various neuropsychiatric and substance use disorders. However, the unique contributions of these regions to stimulus- and action-based reversal learning have not been systematically compared using a chemogenetic approach particularly before and after the first reversal that introduces new uncertainty. Here, we examined the roles of ventrolateral OFC (vlOFC) and BLA during reversal learning. Male and female rats were prepared with inhibitory designer receptors exclusively activated by designer drugs targeting projection neurons in these regions and tested on a series of deterministic and probabilistic reversals during which they learned about stimulus identity or side (left or right) associated with different reward probabilities. Using a counterbalanced within-subject design, we inhibited these regions prior to reversal sessions. We assessed initial and pre-/post-reversal changes in performance to measure learning and adjustments to reversals, respectively. We found that inhibition of the ventrolateral orbitofrontal cortex (vlOFC), but not BLA, eliminated adjustments to stimulus-based reversals. Inhibition of BLA, but not vlOFC, selectively impaired action-based probabilistic reversal learning, leaving deterministic reversal learning intact. vlOFC exhibited a sex-dependent role in early adjustment to action-based reversals, but not in overall learning. These results reveal dissociable roles for BLA and vlOFC in flexible learning and highlight a more crucial role for BLA in learning meaningful changes in the reward environment.

Phenotypic changes of methicillin-resistant Staphylococcus aureus during vancomycin therapy for persistent bacteraemia and related clinical outcome.

Persistent bacteraemia (PB) due to methicillin-resistant Staphylococcus aureus (MRSA) that fails to respond to glycopeptide therapy is a well-documented clinical problem. There are limited data on changes in agr functionality, vancomycin susceptibility and heteroresistance during MRSA PB. Thus, the frequency of these changes and their clinical significance remain unclear. Only patients with MRSA PB (≥7 days) from a prospective cohort of S. aureus bacteraemia were included. We collected isogenic paired strains and compared vancomycin MIC, vancomycin heteroresistance, and agr functionality between initial and final blood isolates. We also assessed the clinical outcome. A total of 49 patients had MRSA PB over 22 months. Bacteraemia persisted for a median of 13 days and most patients (98%) received glycopeptide as initial therapy. Among 49 isogenic pairs, only one pair showed a vancomycin MIC increase ≥2-fold by broth microdilution method, and only seven (14%) by E-test. Significant portions of initial isolates had vancomycin heteroresistance (49%) and agr dysfunction (76%). Development of vancomycin heteroresistance during PB occurred in four (16%) among 25 initial vancomycin-susceptible isolates, and acquisition of agr dysfunction occurred in two (16%) among 12 initial agr-functional isolates. Changes in the opposite direction occasionally occurred. These phenotypic changes during PB were not associated with mortality, whereas agr dysfunction of the initial isolates was significantly associated with mortality. During MRSA PB, phenotypic changes of MRSA isolates occurred occasionally under prolonged vancomycin exposure but were not significantly associated with clinical outcome. In contrast, initial agr dysfunction could be a predictor for mortality in MRSA PB.

Emergence of Panton-Valentine leucocidin-positive ST8-methicillin-resistant Staphylococcus aureus (USA300 clone) in Korea causing healthcare-associated and hospital-acquired bacteraemia.

Panton-Valentine leucocidin (PVL)-positive sequence type (ST)8-MRSA-SCCmec IVa (USA300) is the epidemic strain of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in North America. USA300 is extremely rare in South Korea, and PVL-negative ST72 SCCmec type IVc is the predominant CA-MRSA clone. In a multicentre, prospective cohort study of S. aureus bacteraemia, we identified PVL-positive ST8-MRSA isolates by performing multilocus sequence typing and PCR for PVL. We analyzed the clinical characteristics of patients with PVL-positive ST8-MRSA bacteraemia, and performed SCCmec, spa, and agr typing, PCR for arginine catabolic mobile element (ACME), virulence gene profiling, and pulsed-field gel electrophoresis (PFGE). Among a total of 818 MRSA isolates, we identified ten isolates of PVL-positive ST8-MRSA (USA300) (3 from Hospital D, 4 from Hospital G, and 3 from Hospital A), all of which involved exclusively healthcare-associated (5 isolates) and hospital-acquired bacteraemia (5 isolates). This strain accounted for 8~10 % of the hospital-acquired MRSA bacteraemia in Hospitals D and G. Bacteraemia of unknown origin was the most common type of infection followed by pneumonia. All the isolates were SCCmec type IVa, spa type t008, and agr group I. Eight of the isolates harboured ACME. In a PFGE analysis, four isolates were identical to the USA300 control strain, five differed by a single band, and the remaining one differed by two bands. All the isolates were pulsed-field type USA300. This is the first report of healthcare-associated and hospital-acquired bacteraemia caused by USA300 in South Korea. USA300 seems to be an emerging hospital clone in this country.

Electronic energy and electron transfer processes in photoexcited donor-acceptor dyad and triad molecular systems based on triphenylene and perylene diimide units.

We investigate the photophysical properties of organic donor-acceptor dyad and triad molecular systems based on triphenylene and perylene diimide units linked by a non-conjugated flexible bridge in solution using complementary optical spectroscopy techniques. When these molecules are diluted in dichloromethane solution, energy transfer from the triphenylene to the perylene diimide excited moieties is evidenced by time-resolved fluorescence measurements resulting in a quenching of the emission from the triphenylene moieties. Simultaneously, another quenching process that affects the emission from both donor and acceptor units is observed. Solution ultrafast transient absorption measurements provide evidence of photo-induced charge transfer from either the donor or the acceptor depending upon the excitation. Overall, the analysis of the detailed time-resolved spectroscopic measurements carried out in the dyad and triad systems as well as in the triphenylene and perylene diimide units alone provides useful information both to better understand the relations between energy and charge transfer processes with molecular structures, and for the design of future functional dyad and triad architectures based on donor and acceptor moieties for organic optoelectronic applications.

Prevalence of blaZ gene types and the cefazolin inoculum effect among methicillin-susceptible Staphylococcus aureus blood isolates and their association with multilocus sequence types and clinical outcome.

Cefazolin treatment failures have been described for bacteraemia caused by methicillin-susceptible Staphylococcus aureus (MSSA) with type A ß-lactamase and inoculum effect (InE). We investigated the prevalence of blaZ (ß-lactamase) gene types and a cefazolin InE among MSSA blood isolates in South Korea and evaluated their association with specific genotypes. The clinical impact of the cefazolin InE was also evaluated. A total of 220 MSSA isolates were collected from a prospective cohort study of S. aureus bacteraemia. A pronounced InE with cefazolin was defined as a ≥4-fold increase in the minimum inhibitory concentration (MIC) between a standard and high inoculum, resulting in a non-susceptible MIC. Sequencing of blaZ and multilocus sequence typing (MLST) were performed. Clinical outcomes were assessed in 77 patients treated with cefazolin. The blaZ gene was detected in 92 % of the 220 MSSA isolates. Type C ß-lactamase was the most common (53 %), followed by type B (20 %) and type A (17 %). Certain genotypes were significantly associated with specific ß-lactamase types (notably, ST30 and type A ß-lactamase). A pronounced cefazolin InE was observed in 13 % of isolates. Most of these (79 %) expressed type A ß-lactamase and ST30 was the predominant (55 %) clone amongst them. Cefazolin treatment failure was not observed in patients infected with strains exhibiting a pronounced InE. These strains had no impact on other clinical outcomes. In conclusion, the prevalence of a pronounced InE with cefazolin could be dependent upon distributions of MSSA genotypes. Cefazolin can likely be used for the treatment of MSSA bacteraemia (except endocarditis), without consideration of an InE.

Comparison of the clinical characteristics of Mycobacterium tuberculosis and nontuberculous mycobacteria patients with joint involvement.

Nontuberculous mycobacteria (NTM) joint involvement is rare. However, the incidence of NTM disease is increasing and it is difficult to distinguish NTM from Mycobacterium tuberculosis (MTB). Here, the clinical characteristics of NTM joint involvement were compared with those of MTB. Distal joint involvement and precipitating factors were significantly more frequent for NTM joint infections. Because pathologic findings of NTM and MTB were similar, microbiological investigations are needed.

Electro-optic switching in phase-discontinuity complementary metasurface twisted nematic cell.

Electro-optic switching of refraction is experimentally demonstrated in a phase-discontinuity complementary metasurface twisted nematic cell. The phase-discontinuity complementary metasurface is fabricated by focused-ion-beam milling, and a twisted nematic cell is constructed with complementary V-shape slot antenna metasurface. By application of an external voltage, switching is achieved between ordinary refraction and extraordinary refraction satisfying the generalized Snell's law. It has a strong implication for applications in spatial light modulation and wavelength division multiplexer/demultiplexer in a near-IR spectral range.

Cytomegalovirus infection after acute rejection therapy in seropositive kidney transplant recipients.

BACKGROUND: Acute rejection (AR) after solid organ transplantation has been known to be a risk factor for cytomegalovirus (CMV) infection. However, data regarding the risk for CMV infection during and after anti-rejection therapy are limited. This study investigated whether the risk of CMV infection and disease within 6 months of kidney transplantation (KT) increases in CMV-seropositive KT recipients who develop AR. METHODS: A total of 992 seropositive KT recipients, including 75 patients (8%) who developed AR within 6 months after KT and 917 patients (92%) who did not, were recruited between May 2007 and April 2012. RESULTS: No significant difference was found in the incidence of CMV infection between the groups (AR group, 13% [10/75] vs. non-AR group, 10% [92/917], P = 0.37). The number of KT recipients in each group receiving preemptive therapy for CMV was similar (5% [4/75] vs. 6% [53/917], P > 0.99). While the incidence of CMV syndrome was comparable (0% [0/75] vs. 1% [12/917], P > 0.99), the incidence of tissue-invasive CMV disease (8% [6/75] vs. 3% [27/917], P = 0.04), particularly gastrointestinal CMV disease, was significantly greater in patients who experienced AR. No CMV-related mortality occurred in either group. AR (odds ratio, 2.81; 95% confidence interval, 1.08-7.29; P = 0.03) was an independent risk factor for tissue-invasive CMV disease within 6 months of KT. CONCLUSIONS: A high index of suspicion and active evaluation for tissue-invasive CMV disease in KT recipients suffering AR may be necessary to ensure appropriate treatment.

Reflection resonance switching in metamaterial twisted nematics cell.

Electric switching of reflection resonances at near-IR spectral range is experimentally demonstrated in a reflective metamaterial twisted nematic liquid crystal cell. Reflective metamaterial composed of nano-sized double-split ring resonator aperture is fabricated by a focused ion beam milling. Two-fold rotational symmetry of double-split ring resonators allows for two orthogonal polarization-dependent reflection resonances in the reflective metamaterial. With an external voltage of 10V across 12µm cell gap, a full switching is achieved between two reflection resonances. Dynamic measurements show the time constants of switch-on and switch-off are in the order of 100ms and 10ms, respectively.

agr Dysfunction and persistent methicillin-resistant Staphylococcus aureus bacteremia in patients with removed eradicable foci.

PURPOSE: Persistent Staphylococcus aureus bacteremia (SAB) has been observed in patients with eradicated foci, but there are few studies of the risk factors and clinical outcomes of persistent bacteremia. This study determined the risk factors for persistent methicillin-resistant S. aureus (MRSA) bacteremia in patients without retained eradicable foci, including genotypic characteristics. METHODS: All adult SAB patients were investigated between 2008 and 2010. Persistent bacteremia was defined as bacteremia lasting >7 days after treatment and patients were monitored prospectively. The study included patients without retained eradicable foci, e.g., removed prosthetic devices and intravenous catheters removed after diagnosis, and those without metastatic infections. RESULTS: Persistent bacteremia occurred in 36 % (31/87) SAB patients with eradicated foci. There were no significant differences in successful defervescence (2.0 vs. 2.0 days, P = 0.55) and total length of hospital stay after bacteremia in the persistent bacteremia group and resolved bacteremia group (P = 0.32). The difference in MRSA bacteremia-related 30-day mortality with persistent bacteremia and resolved bacteremia was not significant (P = 0.12). However, agr dysfunction was higher in persistent bacteremia patients (94 %) than those with resolved bacteremia (75 %, P = 0.03). Multivariate analysis using a logistic regression model found that only agr dysfunction [odds ratio (OR) 4.83, 95 % confidence interval (CI) 1.02-22.89, P = 0.04] was an independent risk factor for persistent bacteremia. CONCLUSIONS: This study suggests that persistent bacteremia with eradicated foci might not adversely affect the outcome for MRSA bacteremia patients. agr dysfunction in S. aureus was significantly associated with persistent bacteremia.

Risk factors for false-negative results of T-SPOT.TB and tuberculin skin test in extrapulmonary tuberculosis.

PURPOSE: T-SPOT.TB, a recently developed T cell-based assay, has shown promise in diagnosing extrapulmonary tuberculosis (EPTB). However, a limited number of reports have compared the risk factors for false-negative results of tuberculin skin tests (TSTs) and T-SPOT.TB assays in patients with EPTB. We, thus, conducted a prospective, blinded, observational study to evaluate the risk factors for false-negative T-SPOT.TB and TST results in patients with EPTB. METHODS: Between April 2008 and November 2011, all adult patients with suspected EPTB were prospectively enrolled at Asan Medical Center, Seoul, South Korea (an intermediate TB-burden country). Only patients with confirmed and probable EPTB who underwent TST and T-SPOT.TB were included in the final analysis. RESULTS: Of the 324 patients who underwent both TST and T-SPOT.TB testing, 128 patients with 96 (75 %) culture- or polymerase chain reaction (PCR)-confirmed and 32 (25 %) probable EPTB were finally analyzed. T-SPOT.TB assays were less likely to yield false-negative results than TSTs [17 % (22/128) vs. 54 % (69/128), p < 0.001]. In a multivariate analysis, miliary TB was associated with false-negative TSTs [odds ratio (OR) = 5.3; 95 % confidence interval (CI) 1.7-16.1], while immunosuppression showed a trend toward false-negative TSTs (OR = 2.5; 95 % CI 0.9-6.8). Conversely, lymph node TB (OR = 0.2; 95 % CI 0.1-0.5) and skeletal TB (OR = 0.2; 95 % CI 0.1-0.5) were associated with true-positive TST results. The only risk factor for false-negative T-SPOT.TB results was TB meningitis (OR = 2.6; 95 % CI 1.0-6.6). CONCLUSIONS: Our findings suggest that T-SPOT.TB has a better sensitivity to diagnose EPTB than TST, especially in patients with immunosuppression or miliary TB.

Fabrication of polarization-dependent reflective metamaterial by focused ion beam milling.

By focused ion beam milling, we fabricated near-IR reflective metamaterials consisting of nano-aperture arrays. Optimum parameters of ion beam current and accelerating voltage in the fabrication process are obtained. Nano-apertures constituting reflective metamaterial are successfully milled, and possess a reflective resonance in the near-IR spectral range. With a double-split-ring resonator structure for the nano-aperture, the intensity reflection at resonance is rendered polarization dependent. It is found that the point group symmetry of the nano-aperture array determines the amount of anisotropy in the intensity reflection. Finite-difference time-domain simulation was adopted to identify details of nano-aperture metastructures transferred from nano-aperture patterns by the focused ion beam milling.

Comparison of the QuantiFERON-TB Gold In-Tube test with the tuberculin skin test for detecting latent tuberculosis infection prior to hematopoietic stem cell transplantation.

A total of 244 patients including 100 (41%) autologous hematopoietic stem cell transplant (HCT) recipients and 144 (59%) allogeneic HCT recipients were enrolled over a 28-month period. During the study period, no prophylaxis for latent tuberculosis (TB) infection was administrated. Of these, 201 (82%) had Bacillus Calmette-Guérin (BCG) scars or prior histories of BCG vaccination. The tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube (QFT-GIT) test were performed simultaneously in all 244 patients. TST indurations were ≥ 5 mm in 39 of these patients (15%), and in 25 (10%) indurations were ≥ 10 mm. In addition, 40 (16%) had positive QFT-GIT outcomes, and 34 (14%) indeterminate outcomes. If the 34 patients with indeterminate QFT-GIT results were excluded from the overall agreement analysis, the agreement between the TST results (induration size ≥ 5 mm) and the QFT-GIT results in the 210 patients with clear QFT results was poor (κ = 0.08, 95% confidence interval [CI] -0.06 to 0.24), as it was for the patients with indurations ≥ 10 mm (κ = 0.15, 95% CI -0.004 to 0.31). During follow up, 2 patients developed TB after HCT. The incidence of TB in the patients with positive QFT-GIT outcomes was 2.80 per 100 person-years (95% CI 0.07-15.81), whereas among those with positive TST (≥ 5 mm) results, it was 0 per 100 person-years (95% CI 0-8.00). However, this finding should be cautiously interpreted because of the relatively short follow up and the fact that the sample size of the study cohort did not have adequate power. In conclusion, our data show that, although the frequencies of positive outcomes in the 2 TB screening tests were similar, the overall agreement between the TST and the QFT-GIT test was poor, regardless of BCG vaccination history.

Increased incidence of herpes zoster in the setting of cytomegalovirus preemptive therapy after kidney transplantation.

BACKGROUND: Herpes zoster (HZ) is a common infectious disease after kidney transplantation (KT). The incidence of HZ may increase during cytomegalovirus (CMV) preemptive therapy. We therefore evaluated the incidence, risk factors, and clinical outcomes of HZ after KT, according to the type of CMV prophylaxis used. METHODS: We retrospectively established a cohort of KT recipients who underwent transplantation from June 2008 to May 2010. Patients were categorized into 3 groups according to CMV prophylaxis regimen: Group A (preemptive therapy), Group B (universal prophylaxis <3 months), and Group C (universal prophylaxis >3 months). The incidence rate of HZ was compared in each group, and risk factors for HZ were identified. RESULTS: The incidence rate of HZ was 46.6 (95% confidence interval [CI] 31.4-66.5) per 1000 person-years. The incidence rate was higher in Group A than in Group C (80.0 vs. 13.0 per 1000 person-years; P = 0.001). Median onset time of HZ after KT was shorter in Group A than in Group B (0.9 vs. 9.9 months; P < 0.001) and Group C (0.9 vs. 14.8 months; P = 0.008). Post-herpetic neuralgia occurred in 7 patients (23%). No visceral involvement or death was related to HZ. By multivariate analysis, only female gender (corrected relative risk 1.59; 95% CI 1.09-2.00) was independently associated with HZ development. CONCLUSIONS: In the setting of CMV preemptive therapy, a differentiated varicella zoster virus-specific prophylaxis might be necessary for patients with HZ risk factors.

Exciton diffusion in near-infrared absorbing solution-processed organic thin films.

We report on singlet-singlet annihilation and exciton diffusion in as-prepared p-type and annealed n-type thin films of the low-bandgap quinoidal quaterthiophene [QQT(CN)4] using ultrafast transient absorption measurements. The decay dynamics of exciton populations are well described by a one-dimensional diffusion-limited bimolecular recombination, indicating that the singlet excitons migrate preferentially along the stacking direction. Our results show that the exciton diffusion constants in QQT(CN)4 films do not vary significantly upon thermal annealing. Exciton diffusion lengths are measured to be as high as 4 and 5 nm in as-prepared and annealed QQT(CN)4 films, respectively. We also observe an influence of the excitation densities on the singlet exciton diffusion, which is attributed to phonon scattering. Because of the possibility of patterning p-n regions in QQT(CN)4 films by thermal nanolithography techniques, this study provides important insight not only into the photophysical properties of quinoidal oligothiophene derivatives but also for their future integration into high-performance p-n nanostructured near infrared light-sensing devices.

Development and evaluation of a novel taekwondo chest protector to improve mobility when performing axe kicks.

The axe kick, in Olympic style taekwondo, has been identified as the most popular scoring technique aimed to the head during full contact competition. The first purpose of this study was to identify and investigate design issues with the current World Taekwondo Federation approved chest protector. A secondary purpose was to develop a novel chest protector addressing the identified design issues and to conduct a biomechanical analysis. Fifteen male elite Taekwondo players were selected to perform three different styles of the axe kick, i.e., front, in-out, and out-in axe kick five times each for a total of 45 kicks. Two-way repeated measures ANOVA showed significant differences between the novel and existing chest protector conditions for vertical height of the toe, downward kicking foot speed, hip flexion angle and ipsilateral shoulder flexion extension range of motion (ROM) (p < 0.05). There were no significant differences between the control condition (no chest protector) and the novel chest protector condition for these variables (p > 0.05). These results indicate that the novel chest protector interferes less with both the lower and upper limbs during the performance of the axe kick and provides a more natural, free-moving alternative to the current equipment used.

Anisotropic change in THz resonance of planar metamaterials by liquid crystal and carbon nanotube.

THz metamaterials are employed to examine changes in the meta-resonances when two anisotropic organic materials, liquid crystal and carbon nanotubes, are placed on top of metamaterials. In both anisotropic double split-ring resonators and isotropic four-fold symmetric split-ring resonators, anisotropic interactions between the electric field and organic materials are enhanced in the vicinity of meta-resonances. In liquid crystal, meta-resonance frequency shift is observed with the magneto-optical coupling giving rise to the largest anisotropic shift. In carbon nanotube, meta-resonance absorptions, parallel and perpendicular to nanotube direction, experience different amount of broadening of Lorentzian oscillator of meta-resonance. Investigation reported here opens the application of metamaterials as a sensor for anisotropic materials.

Enterococcus avium bacteremia: a 12-year clinical experience with 53 patients.

Because Enterococcus avium is rarely isolated from blood cultures, little is known about the clinical features and outcomes of bacteremia caused by this organism, formerly called "group Q streptococcus". We retrospectively evaluated the clinical features and outcomes of patients with clinically significant bacteremia caused by E. avium presenting at a tertiary-care hospital in Korea between February 1997 and February 2009. We identified 53 patients over the 12-year period; of these, 27 (50.9%) had biliary and 13 (24.5%) had intra-abdominal E. avium infections. Thirty-six (67.9%) of the episodes were polymicrobial. Thirty-three (62.3%) episodes were nosocomial bloodstream infections and resistance to vancomycin was not observed. The crude mortality rate was 24.5% (13/53), and the E. avium bacteremia-related mortality rate was 11.3% (6/53). Multivariate analysis showed that underlying rapidly fatal or ultimately fatal disease (adjusted odds ratio [AOR], 6.92; 95% confidence interval [CI], 1.56-30.65; P = 0.011) and inadequate antimicrobial therapy (AOR, 7.29; CI, 1.27-41.93; P = 0.026) were independent risk factors for mortality. In summary, bacteremia due to E. avium was commonly of biliary or intraabdominal origin and was often associated with polymicrobial bacteremia. The crude mortality rate was considerable. Severe underlying conditions and inadequate antimicrobial therapy were significant and independent risk factors for crude patient mortality.

Clinical significance of Staphylococcus aureus bacteremia in patients with liver cirrhosis.

Patients with liver cirrhosis (LC) have impaired immunity and thus are predisposed to infections. Few studies have attempted to evaluate Staphylococcus aureus bacteremia (SAB) in LC patients. Therefore, this study prospectively evaluated the clinical characteristics and outcomes of 642 episodes of SAB from August 1, 2008 to September 31, 2010. Of 642 patients with SAB, 109 (17.0 %) were classified as LC patients whereas the remaining 533 (83.0 %) were classified as non-LC patients. The 30-day mortality rate of LC patients was significantly higher than that of patients with other diseases (32 % vs. 22 %, respectively; P = 0.047). The 30-day mortality rates of patients with MSSA bacteremia and MRSA bacteremia were not significantly different among LC patients (35.1 % with MSSA vs. 26.9 % with MRSA; P = 0.41). A univariate analysis of the 30-day mortality rate of LC patients with SAB for survivors and non-survivors showed that rapidly fatal or ultimately fatal according to the criteria of McCabe and Jackson (OR 5.0; 95 % CI 1.60-15.65), septic shock at initial presentation (OR 3.5; 95 % CI 1.18-10.39) and Child-Pugh class C (OR 2.8; 95 % CI 1.20-6.59) were associated with increased mortality. In contrast, the removal of the eradicable focus was associated with decreased mortality (OR 0.14; 95 % CI 0.04-0.52). Disease severity and liver dysfunction may be useful for predicting the prognosis of SAB in LC patients.

Clinical implication of extended-spectrum cephalosporin nonsusceptibility in Streptococcus pneumoniae meningitis.

The clinical implication of extended-spectrum cephalosporin (ESC) resistance has been unclear in patients with Streptococcus pneumoniae meningitis (SPM). We collected the clinical data of 120 patients with SPM in 12 hospitals of the Republic of Korea. The clinical characteristics and outcomes of 23 ESC-nonsusceptible SPM episodes were compared to those of 97 ESC-susceptible episodes. Hospital acquisition, presence of other foci of pneumococcal infection, septic shock at initial presentation, or concomitant bacteremia were more commonly observed in ESC-nonsusceptible than ESC-susceptible SPM. Empiric antimicrobial therapy with vancomycin and ESC combination was very common in both groups. Although there was a tendency towards higher early fatality in ESC-nonsusceptible SPM (3-day mortality; 17.4 % vs. 4.4 %, p = 0.05), in-hospital mortality (26.1 % vs. 20.9 %, p = 0.59) and median length of hospital stay (20 days vs. 24 days, p = 0.34) did not differ between ESC-nonsusceptible and ESC-susceptible SPM.