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Background/aims: Healthcare-associated (HCA) infection is a recently suggested new category of community-onset infections. The implications of HCA infections in terms of diagnosis, treatment, and outcomes of spontaneous bacterial peritonitis (SBP) are not well understood. We sought to delineate the differences between community-acquired (CA) SBP and HCA SBP with specific interest in the antimicrobial resistance of causative microorganisms and outcomes., Methods: We conducted a retrospective cohort study of all SBP episodes with positive ascitic culture and/or blood culture from June 2000 to August 2011. Community-onset SBP episodes were included when they occurred within 48 hours after admission and were classified as CA SBP and HCA SBP based on the predefined criteria., Results: A total of 188 episodes of community-onset SBP were analyzed (65.4% HCA SBP and 34.6% CA SBP). HCA SBP had a higher resistance rate to third-generation cephalosporin (6.8% vs. 1.6%, p = 0.168). The overall 30-day mortality was similar between both groups (37.4% vs. 41.5%, p = 0.638). The independent risk factors for 30-day all-cause mortality in community-onset SBP included high Child-Pugh score, acute kidney injury, and resistance to third-generation cephalosporins; HCA infection was not associated., Conclusion: Hepatic functional status, renal dysfunction, and third-generation cephalosporin resistant pathogens more adversely affected the outcome of cirrhotic patients with community-onset SBP rather than HCA infection. The higher rate of third-generation cephalosporin resistance was notable in HCA SBP, which will require a novel approach to empirical antibiotic treatment selection in this population.

Background: Fluoroquinolones are antibiotics commonly used in the treatment of infections caused by Streptococcus pneumoniae. However, rates of fluoroquinolone resistance are increasing with their frequent use. We designed this study to verify current fluoroquinolone resistance rates and risk factors for community-onset pneumococcal pneumonia., Methods: A retrospective case-control study was conducted in a tertiary referral hospital. The study population comprised patients admitted for pneumococcal pneumonia between January 2011 and May 2017. The case group included community-onset pneumonia caused by levofloxacin-nonsusceptible S. pneumoniae. The control group consisted of two patients with levofloxacin-susceptible S. pneumoniae who were admitted around the same time as each case., Results: A total of 198 pneumococcal pneumonia cases were identified during the study period. Twenty-five levofloxacin-resistant S. pneumoniae cases and 3 levofloxacin-intermediate S. pneumoniae cases were included in the case group (nonsusceptibility rate = 14.1%). Multivariate analysis showed that healthcare-associated factors (odds ratio [OR] 4.78, 95% confidence interval [CI] 1.39-16.43, p = 0.013), bronchopulmonary disease (OR 3.79, 95% CI 1.07-13.40, p = 0.039), cerebrovascular disease (OR 6.08, 95% CI 1.24-29.75, p = 0.026), and exposure to fluoroquinolones within the previous 3 months (OR 5.89, 95% CI 1.21-28.68, p = 0.028) were associated with nonsusceptibility to levofloxacin., Conclusion: Independent risk factors for levofloxacin-nonsusceptible pneumococcal pneumonia were recent hospitalization, bronchopulmonary disease, cerebrovascular disease, and prior antibiotic use within 3 months. Careful selection of empirical antibiotics is thus needed in at-risk patients. Similarly, efforts to prevent the interpersonal spread of drug-resistant pathogens in long-term care facilities and to restrict unnecessary fluoroquinolone prescriptions are important.

Objectives: We previously reported the first case of vancomycin treatment failure due to development of vancomycin-intermediate resistance in a patient with an MRSA of ST72, a community genotype in Korea. We investigated two isogenic MRSA strains from this patient, who experienced treatment failure with vancomycin and rifampicin., Methods: We tracked the genetic alterations that confer reduced susceptibility to vancomycin on those two isogenic MRSA strains by WGS., Results: Five non-synonymous mutations were identified, including rpoB (H481Y), dprA (G196C), femA (F92C), vraR (E127K) and agrC (E391stop). We further studied the role of a mutation of vraR in reduced susceptibility to vancomycin. Introduction of the mutated vraR (E127K) into a vancomycin-susceptible Staphylococcus aureus strain resulted in an increase in vraSR mRNA expression and vancomycin MIC and development of the hetero-VISA phenotype, which was confirmed by the population analysis profile (PAP)/AUC. Electron microscopy showed increased cell wall thickness in the strains with mutated vraR., Conclusions: Based on the genomic data, molecular experiments and PAP and cell wall analyses, we propose that a single mutation of vraR is associated with the reduced susceptibility to vancomycin in MRSA and further treatment failure., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as an important cause of healthcare-associated infection. CA-MRSA clones have replaced classic hospital MRSA clones in many countries and have shown higher potential in transmission and virulence than hospital MRSA clones. In particular, the emergence of CA-MRSA in the Asia-Pacific region is concerning owing to insufficient infection control measures in the region. The old strategies for infection prevention and control of MRSA comprised adherence to standard precaution and policy of active screening of MRSA carriers and decolonization, and it has been controversial which strategy is better in terms of outcome and cost-effectiveness. Epidemiological changes in MRSA has made the development of infection prevention strategy more complicated. Based on the literature review and the questionnaire survey, we considered infection prevention strategies for healthcare settings in the Asia-Pacific region in the era of CA-MRSA., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background/aims: Although multidrug resistance (MDR) among extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) poses significant therapeutic challenges, little is known regarding the risk factors and epidemiology of community-onset MDR-ESBL-EC infections. We performed this study to investigate risk factors and the molecular epidemiology of community-onset MDR-ESBL-EC infections., Methods: We conducted a case-control-control study of community-onset infections. MDR-ESBL-EC was defined as ESBL-EC that demonstrated in vitro resistance to trimethoprim-sulfamethoxazole, fluoroquinolones (FQs), and gentamicin. Patients with MDR-ESBL-EC infections were designated as case patients. A control group I (CG I) patient was defined as a person whose clinical sample yielded ESBL-EC that did not meet the criteria for MDR. A control group II (CG II) patient was defined as a patient with a non-ESBL-EC infection., Results: Of 108 patients with ESBL-EC infections, 30 cases (27.8%) were due to MDR-ESBL-EC. Compared with CG I, prior use of FQs (odds ratio [OR], 3.16; 95% confidence interval [CI], 1.11 to 8.98) and immunosuppressant use (OR, 10.47; 95% CI, 1.07 to 102.57) were significantly associated with MDR-ESBL-EC. Compared with CG II, prior use of FQs (OR, 15.53; 95% CI, 2.86 to 84.27) and healthcare-associated infection (OR, 5.98; 95% CI, 2.26 to 15.86) were significantly associated with MDR-ESBL-EC. CTX-M-15 was the most common in MDR-ESBL-EC infections (59.1% [13/22]), while CTX-M-14 was the most common in non-MDR-ESBL-EC infections (41.6% [32/77]). CTX-M-15 was significantly associated with MDR-ESBL-EC (59.1% vs. 32.5%, p = 0.028). Pulsed-field gel electrophoresis showed clonal diversity of MDR-ESBL-EC isolates., Conclusions: The emergence of strains of MDR-ESBL-EC in the community poses an important new public health threat. More information on the emergence and transmission of these strains will be necessary in order to prevent their spread., Competing Interests: No potential conflict of interest relevant to this article was reported.

Community-acquired pneumonia (CAP) is an important cause of mortality and morbidity worldwide. Aging population, dense urbanization, and poor access to health care make the Asia-Pacific region vulnerable to CAP. The high incidence of CAP poses a significant health and economic burden in this region. Common etiologic agents in other global regions including Streptococcus pneumoniae , Mycoplasma pneumoniae , Haemophilus influenzae , Chlamydophila pneumoniae , Staphylococcus aureus , and respiratory viruses are also the most prevalent pathogens in the Asia-Pacific region. But the higher incidence of Klebsiella pneumoniae and the presence of Burkholderia pseudomallei are unique to the region. The high prevalence of antimicrobial resistance in S. pneumoniae and M. pneumoniae has been raising the need for more prudent use of antibiotics. Emergence and spread of community-acquired methicillin-resistant S. aureus deserve attention, while the risk has not reached significant level yet in cases of CAP. Given a clinical and socioeconomic importance of CAP, further effort to better understand the epidemiology and impact of CAP is warranted in the Asia-Pacific region., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

The pneumonia severity index (PSI) and CURB-65 are widely used tools for the prediction of community-acquired pneumonia (CAP). This study was conducted to evaluate validation of severity scoring system including the PSI and CURB-65 scores of Korean CAP patients. In the prospective CAP cohort (participated in by 14 hospitals in Korea from January 2009 to September 2011), 883 patients aged over 18 yr were studied. The 30-day mortalities of all patients were calculated with their PSI index classes and CURB scores. The overall mortality rate was 4.5% (40/883). The mortality rates per CURB-65 score were as follows: score 0, 2.3% (6/260); score 1, 4.0% (12/300); score 2, 6.0% (13/216); score 3, 5.7% (5/88); score 4, 23.5% (4/17); and score 5, 0% (0/2). Mortality rate with PSI risk class were as follows: I, 2.3% (4/174); II, 2.7% (5/182); III, 2.3% (5/213); IV, 4.5% (11/245); and V, 21.7% (15/69). The subgroup mortality rate of Korean CAP patients varies based on the severity scores and CURB-65 is more valid for the lower scores, and PSI, for the higher scores. Thus, these variations must be considered when using PSI and CURB-65 for CAP in Korean patients.

Background: Although extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli has emerged as a significant pathogen, there is little information regarding treatment outcomes in community-onset bacteremia due to ESBL E. coli. The purpose of this study was to evaluate treatment outcomes of community-onset bacteremia caused by ESBL-producing E. coli and the factors associated with mortality., Methods: A retrospective cohort study was performed, including 92 adult patients with community-onset bacteremia caused by ESBL-producing E. coli., Results: The 30-day mortality rate was 10.9% (10/92). Independent risk factors for mortality were underlying liver disease and severity of illness (e.g., high Pitt bacteremia score, the presence of severe sepsis or septic shock; p < 0.05). Mortality in patients receiving inappropriate initial antimicrobial therapy was not significantly higher than mortality in those receiving appropriate empirical antimicrobial therapy (10.9 vs 10.7%; p = 0.975), if antimicrobial therapy was adjusted appropriately according to susceptibility results. Carbapenems, piperacillin/tazobactam, fluoroquinolones, and amikacin were the most effective antibiotics for community-onset bacteremia caused by ESBL-producing E. coli, although susceptibility profiles confirmed that alternatives to carbapenems are limited. Of 68 isolates in which the ESBLs and their molecular relationships were studied, all isolates produced ESBLs from the CTX-M family (CTX-M-14, 30 isolates; CTX-M-15, 22; and other CTX-M, 16)., Conclusions: In patients with community-onset bacteremia caused by ESBL-producing E. coli, severe sepsis and underlying liver disease were significantly associated with mortality, and a delay in appropriate antimicrobial therapy was not associated with a higher mortality if therapy was adjusted appropriately according to the susceptibility results.

Although extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) has emerged as a significant community-acquired pathogen, there is little epidemiological information regarding community-onset bacteremia due to ESBL-EC. A retrospective observational study from 2006 through 2011 was performed to evaluate the epidemiology of community-onset bacteremia caused by ESBL-EC. In a six-year period, the proportion of ESBL-EC responsible for causing community-onset bacteremia had increased significantly, from 3.6% in 2006 to 14.3%, in 2011. Of the 97 clinically evaluable cases with ESBL-EC bacteremia, 32 (33.0%) were further classified as healthcare-associated infections. The most common site of infection was urinary tract infection (n=35, 36.1%), followed by biliary tract infections (n=29, 29.9%). Of the 103 ESBL-EC isolates, 43 (41.7%) produced CTX-M-14 and 36 (35.0%) produced CTX-M-15. In the multilocus sequence typing (MLST) analysis of 76 isolates with CTX-M-14 or -15 type ESBLs, the most prevalent sequence type (ST) was ST131 (n=15, 19.7%), followed by ST405 (n=12, 15.8%) and ST648 (n=8, 10.5%). No significant differences in clinical features were found in the ST131 group versus the other group. These findings suggest that epidemic ESBL-EC clones such as CTX-M-14 or -15 type ESBLs and ST131 have disseminated in community-onset infections, even in bloodstream infections, which are the most serious type of infection.

Objective: This study was performed to identify risk factors for the development of bacteremic pneumonia and to evaluate the impact of bacteremia on the outcome of pneumococcal pneumonia., Methods: Using a database from a surveillance study of community-acquired pneumococcal pneumonia, we compared data of the bacteremic group with that of the non-bacteremic group., Results: Among 981 adult patients with pneumococcal pneumonia, 114 (11.6%) patients who had documented pneumococcal bacteremia were classified into the bacteremic group. In a multivariable analysis, use of immunosuppressant drugs, younger age (<65 years), and DM were independent risk factors associated with the development of bacteremic pneumonia among patients with pneumococcal pneumonia (all P < 0.05). The mortality rate was significantly higher in the bacteremic group than in the non-bacteremic group (28.6% vs. 8.5%; P < 0.001). The multivariable analysis revealed that concomitant bacteremia was one of the significant risk factors associated with mortality (OR, 2.57; 95% CI, 1.24-5.29), along with cerebrovascular disease and presentation with septic shock (all P < 0.05)., Conclusions: Bacteremia was a common finding in pneumococcal pneumonia and was associated with a higher mortality rate. Several clinical variables may be useful for predicting bacteremic pneumonia among patients with pneumococcal pneumonia., (Copyright © 2012. Published by Elsevier Ltd.)

Background: Tigecycline has broad spectrum antimicrobial activity and is approved for complicated intra-abdominal infections, complicated skin and soft tissue infections, and community-acquired pneumonia. There are few data on clinical experience of tigecycline in hospital-acquired pneumonia (HAP) and Acinetobacter spp. infection., Methods: A retrospective study was performed at eight hospitals in Korea from May 2009 to January 2010. Adult patients treated with tigecycline regardless of their source of infection or pathogens were enrolled., Results: Tigecycline was administered in 108 patients. Pneumonia was the most common infection (43.5%), followed by skin and soft tissue infections (20.4%). Acinetobacter baumannii was isolated from 83 patients (76.9%) accounting for 50.3% of isolated pathogens, showing a resistance rate of 67.5% to carbapenems. Superinfection was identified in 32 patients (29.6%). Pseudomonas aeruginosa was most common microorganism causing superinfection (46.9%). Overall 30-day mortality rate was 52.9%. Thirty-day mortality rate of HAP and Acinetobacter spp. infection was 60.5% and 59.4%, respectively., Conclusion: Tigecycline can be considered as an alternative therapy in patients with HAP or infections caused by Acinetobacter spp., especially extensively drug-resistant A. baumannii.

Objectives: Community-genotype methicillin-resistant Staphylococcus aureus (MRSA) clones have emerged in the community worldwide and recently have been spreading into the hospitals. To identify predictors of sequence type 72-MRSA-SCCmec type IV (ST72-MRSA-IV) in patients with community-onset (CO) S. aureus infection, a case-control study was conducted among CO S. aureus infections, including healthcare-associated infections., Methods: Eighty-four patients with CO infections caused by ST72-MRSA-IV strains in Korea between 2007 and 2009 were selected as cases. Members of the control group were those with CO methicillin-susceptible S. aureus infections and they were matched by the admission date in a 1 : 1 ratio., Results: The most common type of infection was skin and soft tissue infection in both groups (48.8% versus 52.4%), followed by pneumonia. Female sex (OR 2.55, 95% CI 1.30-5.04), severe sepsis or septic shock (OR 3.05, 95% CI 1.09-8.55), prior hospitalization within the previous year (OR 2.18, 95% CI 1.10-4.32) and surgical site infection (SSI) (OR 4.63, 95% CI 1.38-15.59) were associated with ST72-MRSA-IV infections in multivariate analyses., Conclusions: Female sex, SSI, severe sepsis or septic shock and prior hospitalization within the previous year were predictors of ST72-MRSA-IV among patients with CO S. aureus infection.

Goal of Work: This study was performed to evaluate the clinical features and outcomes of Staphylococcus aureus infection in non-neutropenic cancer patients., Materials and Methods: From the database of a surveillance study for S. aureus infections, the data regarding S. aureus infections in non-neutropenic cancer patients were analyzed., Main Results: Of 649 non-neutropenic cancer patients with S. aureus infections, 156 (24.0%) had a central venous catheter and 176 (27.1%) had an indwelling urinary catheter. The prevalence of methicillin-resistant S. aureus (MRSA) infections was 54.7% (355 out of 649). As for types of infection, skin and soft tissue infections were the most common (n = 173, 26.7%), followed by pneumonia (n = 165, 25.4%) and primary bacteremia (n = 91; 14.0%). Overall, the 30-day mortality rate was 28.2% (124 out of 440), 34.1% (73 out of 214) in MRSA group, and 22.6% (51 out of 226) in methicillin-sensitive S. aureus group (P = 0.007). When outcomes according to the types of infection were evaluated, the mortality rates were 49.5% (53 out of 107) for pneumonia and 41.2% (49 out of 119) for bacteremia. Multivariate analysis showed that pneumonia, concomitant bacteremia, comorbid liver disease, and intubated state with ICU care were independent risk factors associated with 30-day mortality., Conclusion: Our study demonstrated that S. aureus infections in cancer patients are serious clinical conditions with high mortality rates, even in non-neutropenic patients.

Panton-Valentine leukocidin (PVL)-positive USA300 clone has been the most successful community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) clone spreading in North America. In contrast, PVL-negative ST72-CA-MRSA has been predominant in Korea, and there has been no report of infections by the USA300 strain except only one case report of perianal infection. Here, we describe the first case of pneumonia caused by the USA300 strain following pandemic influenza A (H1N1) in Korea. A 50-year-old man was admitted with fever and cough and chest radiograph showed pneumonic consolidation at the right lower lung zone. He received a ventilator support because of respiratory failure. PCR for pandemic influenza A (H1N1) in nasopharyngeal swab was positive, and culture of sputum and endotracheal aspirate grew MRSA. Typing of the isolate revealed that it was PVL-positive, ST 8-MRSA-SCCmec type IV. The analysis of the PFGE patterns showed that this isolate was the same pulsotype as the USA300 strain.

Limited clinical information is available regarding community onset infections caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. A case-control study was performed to evaluate the epidemiology and risk factors of these types of infections. A case patient was defined as a person whose clinical sample yielded ESBL-producing E. coli. For each case patient, one control was randomly chosen from a group of outpatients from whom non-ESBL-producing E. coli had been isolated and for whom a clinical sample had been sent to the same laboratory for culturing during the following week. Of 108 cases of ESBL-producing E. coli, 56 (51.9%) were classified as health care associated (HCA). Univariate analysis showed male gender, HCA infection, severe underlying illness, and a prior receipt of antibiotics to be associated with ESBL-producing E. coli. In the multivariate analysis, HCA infection (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.67 to 6.06; P < 0.001) and previous use of antibiotics (OR, 4.88; 95% CI, 2.08 to 11.48; P < 0.001) were found to be significantly associated with the ESBL group. In a multivariate analysis that included each antibiotic, previous use of fluoroquinolone (OR, 7.32; 95% CI, 1.58 to 34.01; P = 0.011) was significantly associated with ESBL-producing E. coli. Of 101 isolates in which ESBLs and their molecular relationships were studied, all isolates produced ESBLs from the CTX-M family (CTX-M-14, 40 isolates; CTX-M-15, 39 isolates; and other members of the CTX-M family, 22 isolates). In conclusion, this study confirms that ESBL-producing E. coli strains are a notable cause of community onset infections in predisposed patients. HCA infection and previous use of fluoroquinolone were significant factors associated with ESBL-producing E. coli in community onset infections.

Background: Clinical and microbiological characteristics of healthcare-associated acute pyelonephritis (HCA-APN) have not been described in detail yet. We sought to delineate the differences between community-associated (CA)- and HCA-APN with specific interest in antibiotic resistance of causative microorganisms., Methods: We conducted a retrospective cohort study during a 1-y period at a large referral center. Patients who visited the emergency department with symptoms and signs of APN were included in the study population., Results: Among 319 cases with community-onset APN, 201 cases (63%) were classified as HCA-APN. Patients with HCA-APN had higher SOFA (sequential organ failure assessment) scores, longer length of hospital stay and a lower rate of complete response to antimicrobial therapy. Patients with complicated APN also had characteristics similar to those seen in HCA-APN. However, 14-day mortality rates were not different between CA-APN vs HCA-APN and between uncomplicated APN vs complicated APN. With regard to microbiological characteristics, Escherichia coli were less common in HCA-APN than in CA-APN (62.7% vs 93.2%, p < 0.001). Among E. coli isolates, quinolone resistance and extended-spectrum beta-lactamase (ESBL) production were more common in HCA-APN than in CA-APN (38.9% vs 12.7%, p < 0.001; 15.9% vs 0.8%, p < 0.001, respectively)., Conclusions: HCA-APN, and complicated APN, represents a distinct subset of urinary tract infections with more antibiotic-resistant pathogens and worse outcomes, which physicians should consider to provide optimal treatment.

There is limited clinical information regarding community-onset bacteremia caused by extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae. This study was performed to evaluate risk factors and clinical outcomes of community-onset bacteremia caused by ESBL-producing K. pneumoniae. A total of 435 patients with community-onset K. pneumoniae bacteremia were included and data from patients with ESBL-producing K. pneumoniae bacteremia were compared to those with non-ESBL-producing bacteremia. Isolates with ESBLs were microbiologically characterized. Of 435 patients with community-onset K. pneumoniae bacteremia, 33 (7.6%) were infected with ESBL producers, of which 25 were further classified as healthcare-associated infections. The most common underlying diseases were solid tumors (n = 20, 60.6%) and diabetes mellitus (n = 10, 30.3%), and the most common infection was intra-abdominal infection (n = 20, 60.6%). Multivariate analysis showed that corticosteroid use (odds ratio [OR] = 13.73, 95% confidence interval [CI] = 1.93-97.6, p = 0.009), percutaneous tubes (OR = 7.30, 95% CI = 2.41-22.12, p < 0.001), and prior receipt of antibiotics (OR = 5.65, 95% CI = 2.43-14.16, p < 0.001) were significant factors associated with ESBL producers. When the 30-day mortality rate was evaluated, no significant difference was found between ESBL group and non-ESBL group (12.1% [4/32] vs. 16.0% [35/192]; p = 0.429). Among 16 isolates, for which the ESBL characterization was performed by PCR, the most common types of ESBLs were SHV (n = 16) and cefotaxime-M-2 (n = 5). Pulsed-field gel electrophoresis analysis of the ESBL-producing organisms showed extensive clonal diversity. ESBL-producing K. pneumoniae is a significant cause of bacteremia, even in patients with community-onset infections, particularly in patients with corticosteroid use, percutaneous tube, prior receipt of antibiotics, or healthcare-associated infections.

Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is highly prevalent in hospitals in many Asian countries. Recent emergence of community-associated (CA) MRSA worldwide has added another serious concern to the epidemiology of S. aureus infections. To understand the changing epidemiology of S. aureus infections in Asian countries, we performed a prospective, multinational surveillance study with molecular typing analysis., Methods: We evaluated the prevalence of methicillin resistance in S. aureus isolates in CA and healthcare-associated (HA) infections, and performed molecular characterization and antimicrobial susceptibility tests of MRSA isolates., Results: MRSA accounted for 25.5% of CA S. aureus infections and 67.4% of HA infections. Predominant clones of CA-MRSA isolates were ST59-MRSA-SCCmec type IV-spa type t437, ST30-MRSA-SCCmec type IV-spa type t019 and ST72-MRSA-SCCmec type IV-spa type t324. Previously established nosocomial MRSA strains including sequence type (ST) 239 and ST5 clones were found among CA-MRSA isolates from patients without any risk factors for HA-MRSA infection. CA-MRSA clones such as ST59, ST30 and ST72 were also isolated from patients with HA infections., Conclusions: Our findings confirmed that MRSA infections in the community have been increasing in Asian countries. Data also suggest that various MRSA clones have spread between the community and hospitals as well as between countries.

Background: Although hospital-acquired infections presumably may have a poorer prognosis than community-onset infections because of unanticipated antimicrobial resistance, little data are available on the clinical and microbiological characteristics of hospital-acquired versus community-onset urinary tract-related bacteremia cases., Methods: Data were collected from a nationwide database of surveillance for bacteremia. Data from patients with hospital-acquired urinary tract-related bacteremia were compared with those with community-onset bacteremia., Results: Of 398 patients with urinary tract-related bacteremia, 71 (17.8%) had hospital-acquired infection, and the remaining 327 (82.2%) had community-onset infection. Although Escherichia coli was the most common isolate identified, pathogens other than E coli were more frequently isolated in hospital-acquired infections than in community-onset infections (46.5% vs 19.3%). Among E coli isolates causing hospital-acquired infections, 26.3% (10 of 38) were resistant to extended-spectrum cephalosporins (ESCs), whereas among E coli isolates causing community-onset infections, only 6.1% (16 of 264) were ESC-resistant. Hospital-acquired infection had a significantly higher mortality rate than community-onset infection (21.1% [15 of 71] vs 8.3% [27 of 327]; P = .004). Multivariate analysis identified nosocomial acquisition as a significant independent risk factor for mortality, along with severe sepsis, underlying solid tumor, ESC resistance, and high Pitt bacteremia score (all P < .05)., Conclusion: Hospital-acquired urinary tract-related bacteremia has a poorer prognosis than community-onset bacteremia. The ESC-resistant nature of gram-negative bacilli, which may be more common in nosocomial isolates than in community isolates, adversely affects the outcome of urinary tract-related bacteremia., (Copyright © 2011 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.)

Objectives: As ciprofloxacin resistance rate of Escherichia coli causing urinary tract infections has been increasing, concern about inappropriate empirical therapy has been arisen., Methods: We performed a retrospective cohort study to determine the impact of discordant empirical antimicrobial therapy on outcome of community-acquired bacteremic acute pyelonephritis., Results: Among a total of 164 cases included, ciprofloxacin was empirically used in 80.5%. The most frequent etiologic organism was E. coli (92.1%), of which 20.5% was resistant to ciprofloxacin. Discordant empirical therapy was documented in 29 cases, which included 25 cases caused by ciprofloxacin-resistant E. coli. Discordant therapy resulted in lower early clinical response rate (34.5% vs. 82.2%; P < 0.001) and longer hospital stay (13.3 days vs. 8.7 days; P = 0.002) compared to concordant therapy. However, overall mortality and clinical cure rate did not differ between two groups. Multivariate analyses showed that worse early clinical response was associated with discordant empirical therapy (OR, 11.08; 95% CI, 4.37-28.07) and presentation with septic shock (OR, 8.52; 95% CI, 1.75-41.49). Longer hospital stay was also associated with discordant empirical therapy (OR, 2.47; 95% CI, 1.04-5.84)., Conclusions: Discordant empirical therapy, mostly with ciprofloxacin, leads to worse early clinical response and longer hospital stay than concordant therapy in community-acquired bacteremic acute pyelonephritis, although it does not affect on overall mortality or clinical cure rate., (Copyright © 2010 The British Infection Association. Published by Elsevier Ltd. All rights reserved.)

The purpose of this study was to identify risk factors for extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli amongst community-onset bacteraemia and to evaluate treatment outcomes. From the database of a nationwide surveillance programme for bacteraemia, data from patients with community-onset E. coli bacteraemia were analysed. Patients with ESBL-producing E. coli bacteraemia were compared with those with non-ESBL-producing bacteraemia. The overall proportion of ESBL-producers was 9.5% (82/865) amongst community-onset E. coli bacteraemia cases. Healthcare-associated infection, underlying liver disease and primary bacteraemia were significant independent factors associated with ESBL-producing E. coli bacteraemia (P<0.05). There was a trend toward mortality being higher in the ESBL group compared with the non-ESBL group (15.0% vs. 7.6%; P=0.096). ESBL production was found to be an independent factor associated with mortality after adjusting for confounding variables (odds ratio=2.99, 95% confidence interval 1.01-8.84; P=0.048), along with severe sepsis, higher Pitt bacteraemia score, primary bacteraemia, pneumonia and underlying liver disease (P<0.05). ESBL-producing E. coli is a significant cause of bacteraemia, even in patients with community-onset infections, predicting higher mortality, particularly in patients with primary bacteraemia, underlying liver disease or healthcare-associated infection., (Copyright (c) 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.)

Recent changes in healthcare systems have changed the epidemiologic paradigms in many infectious fields including bloodstream infection (BSI). We compared clinical characteristics of community-acquired (CA), hospital-acquired (HA), and healthcare-associated (HCA) BSI. We performed a prospective nationwide multicenter surveillance study from 9 university hospitals in Korea. Total 1,605 blood isolates were collected from 2006 to 2007, and 1,144 isolates were considered true pathogens. HA-BSI accounted for 48.8%, CA-BSI for 33.2%, and HCA-BSI for 18.0%. HA-BSI and HCA-BSI were more likely to have severe comorbidities. Escherichia coli was the most common isolate in CA-BSI (47.1%) and HCA-BSI (27.2%). In contrast, Staphylococcus aureus (15.2%), coagulase-negative Staphylococcus (15.1%) were the common isolates in HA-BSI. The rate of appropriate empiric antimicrobial therapy was the highest in CA-BSI (89.0%) followed by HCA-BSI (76.4%), and HA-BSI (75.0%). The 30-day mortality rate was the highest in HA-BSI (23.0%) followed by HCA-BSI (18.4%), and CA-BSI (10.2%). High Pitt score and inappropriate empirical antibiotic therapy were the independent risk factors for mortality by multivariate analysis. In conclusion, the present data suggest that clinical features, outcome, and microbiologic features of causative pathogens vary by origin of BSI. Especially, HCA-BSI shows unique clinical characteristics, which should be considered a distinct category for more appropriate antibiotic treatment.

Panton-Valentine leukocidin (PVL)-negative, SCCmec type IVa strains are the most common strains of methicillin-resistant Staphylococcus aureus (MRSA) circulating in the community in South Korea. This report describes five elderly patients presenting in 2006 to 2007 with invasive community-associated MRSA infection caused by a PVL-negative, SCCmec type IVa strain with sequence type 72 and spa type t324.

Background: Pseudomonas aeruginosa bacteremia is a serious and possibly fatal condition. It is important to determine the likelihood of P. aeruginosa bacteremia when Gram-negative sepsis is suspected in community-onset infection., Methods: We performed a retrospective cohort study to identify the risk factors for P. aeruginosa infection in community-onset Gram-negative bacteremia., Results: A total of 106 patients with P. aeruginosa bacteremia and a total 508 patients with E. coli bacteremia were included in this study. Factors associated with P. aeruginosa bacteremia in the multivariate analysis included presentation with neutropenia, presentation with septic shock, indwelling central venous catheter, and health-care-associated infection (all P <.05). The 30-day mortality rate was 26.4% in patients with P. aeruginosa and 13.6% in those with E. coli bacteremia (P <.001). Multivariate analysis demonstrated that risk factors for mortality included a P. aeruginosa bacteremia, inappropriate initial antimicrobial therapy, a higher Charlson's weighted index of comorbidity, and a higher Pitt bacteremia score (all P <.05). In addition, urinary tract infection and benign pancreatobiliary disease were found to be protective factors for mortality based on multivariate analysis (all P <.05)., Conclusions: Our data suggest that initial empirical antimicrobial coverage of P. aeruginosa should be seriously considered in patients with neutropenia, presentation with septic shock, indwelling central venous catheter, or health-care-associated infection, when Gram-negative sepsis is suspected in community-onset infection.

Appropriate antimicrobial treatment of community-acquired pneumonia (CAP) should be based on the distribution of aetiological pathogens, antimicrobial resistance of major pathogens, clinical characteristics and outcomes. We performed a prospective observational study of 955 cases of adult CAP in 14 hospitals in eight Asian countries. Microbiological evaluation to determine etiological pathogens as well as clinical evaluation was performed. Bronchopulmonary disease (29.9%) was the most frequent underlying disease, followed by cardiovascular diseases (19.9%), malignancy (11.7%) and neurological disorder (8.2%). Streptococcus pneumoniae (29.2%) was the most common isolate, followed by Klebsiella pneumoniae (15.4%) and Haemophilus influenzae (15.1%). Serological tests were positive for Mycoplasma pneumoniae (11.0%) and Chlamydia pneumoniae (13.4%). Only 1.1% was positive for Legionella pneumophila by urinary antigen test. Of the pneumococcal isolates, 56.1% were resistant to erythromycin and 52.6% were not susceptible to penicillin. Seventeen percent of CAP had mixed infection, especially S. pneumoniae with C. pneumoniae. The overall mortality rate was 7.3%, and nursing home residence, mechanical ventilation, malignancy, cardiovascular diseases, respiratory rate>30/min and hyponatraemia were significant independent risk factors for mortality by multivariate analysis (P<0.05). The current data provide relevant information about pathogen distribution and antimicrobial resistance of major pathogens of CAP as well as clinical outcomes of illness in Asian countries.

Background: The increasing antimicrobial resistance of Escherichia coli infection is of great concern, even for community-onset infections., Methods: We conducted a retrospective cohort study of patients with E. coli bacteraemia who visited the emergency department of the Samsung Medical Center from February 2002 to December 2005 to identify the risk factors for mortality and association between healthcare-associated (HCA) infection and mortality. We classified community-onset E. coli bacteraemia into community-acquired (CA) and HCA infections., Results: A total of 508 patients with E. coli bacteraemia were enrolled (mean age, 61.8 +/- 14.3 years; male/female, 191:317). The HCA E. coli bacteraemia had significantly higher severity of illness and higher antimicrobial resistance rate than CA bacteraemia. The overall 30-day mortality rate was 13.6% (69/508) and the mortality of HCA infections was significantly higher than that of CA infections (26.4% versus 9.6%, P < 0.001). In multivariate analysis, high Charlson's co-morbidity index (OR 4.84, 95% CI 2.14-10.95, P < 0.001), high Pitt bacteraemia score (OR 32.03, 95% CI 13.08-74.43, P < 0.001), presentation with acute renal failure (OR 4.11, 95% CI 1.90-8.89, P < 0.001) and HCA bacteraemia (OR 2.34, 95% CI 1.09-5.01, P = 0.030) were found to be the significant risk factors for 30-day mortality in E. coli bacteraemia., Conclusions: The mortality rate of HCA E. coli bacteraemia was higher than twice that of CA bacteraemia and HCA bacteraemia was one of the significant risk factors for mortality, even after adjusting for a large number of potential confounders.

Objectives: We previously reported the first case of vancomycin treatment failure due to development of vancomycin-intermediate resistance in a patient with an MRSA of ST72, a community genotype in Korea. We investigated two isogenic MRSA strains from this patient, who experienced treatment failure with vancomycin and rifampicin.Methods: We tracked the genetic alterations that confer reduced susceptibility to vancomycin on those two isogenic MRSA strains by WGS.Results: Five non-synonymous mutations were identified, including rpoB (H481Y), dprA (G196C), femA (F92C), vraR (E127K) and agrC (E391stop). We further studied the role of a mutation of vraR in reduced susceptibility to vancomycin. Introduction of the mutated vraR (E127K) into a vancomycin-susceptible Staphylococcus aureus strain resulted in an increase in vraSR mRNA expression and vancomycin MIC and development of the hetero-VISA phenotype, which was confirmed by the population analysis profile (PAP)/AUC. Electron microscopy showed increased cell wall thickness in the strains with mutated vraR.Conclusions: Based on the genomic data, molecular experiments and PAP and cell wall analyses, we propose that a single mutation of vraR is associated with the reduced susceptibility to vancomycin in MRSA and further treatment failure. [ABSTRACT FROM AUTHOR]

Introduction: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become an important threat to public health in the Asia-Pacific region, which is characterized by a large population and relatively insufficient resources. Better understanding on the current status of CA-MRSA in the region is of paramount importance. Areas covered: This article reviews the published literatures on the prevalence, molecular epidemiology, colonization, and hospital spread of CA-MRSA. Expert commentary: The burden of CA-MRSA has been increasing in the past two decades. The molecular epidemiology of CA-MRSA in the Asia-Pacific region shows a marked diversity in each country. Still, some strains - multilocus sequence type (MLST) ST59, ST30, ST72, ST8, and ST772 - are unique clones that have successfully established themselves as predominant, often spreading into nosocomial settings. More coordinated and comprehensive surveillance to understand the true epidemiology of CA-MRSA in the Asia-Pacific region is urgently needed. [ABSTRACT FROM AUTHOR]