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Featured researches published by Nai Ying Ko.


Journal of Internal Medicine | 2006

Clinical implications of hypermucoviscosity phenotype in Klebsiella pneumoniae isolates: association with invasive syndrome in patients with community-acquired bacteraemia.

Hsin Chun Lee; Yin Ching Chuang; Wen-Liang Yu; Nan Yao Lee; Chia Ming Chang; Nai Ying Ko; Li Rong Wang; Wen Chien Ko

Background.  Klebsiella pneumoniae, a Gram‐negative bacillus usually forming glistening mucoid colonies with viscid consistency on the culture plate, is a common pathogen causing various clinical infection patterns. However, little is known about the clinical implications of this mucoid character.


Journal of Internal Medicine | 2007

Extraintestinal focal infections in adults with nontyphoid Salmonella bacteraemia: predisposing factors and clinical outcome

P. L. Chen; Chia Ming Chang; C. J. Wu; Nai Ying Ko; Nan Yao Lee; Hsin Chun Lee; H. I. Shih; C. C. Lee; R. R. Wang; Wen Chien Ko

Background.  Nontyphoid Salmonella (NTS) isolates lead to not only self‐limited, acute gastrointestinal infections, but also bacteraemia with or without extraintestinal focal infections (EFIs). The risk factors associated with EFIs in adults with NTS bacteraemia were not clearly elucidated.


Diagnostic Microbiology and Infectious Disease | 2008

Necrotizing fasciitis in patients with liver cirrhosis: predominance of monomicrobial Gram-negative bacillary infections

Ching Chi Lee; Chih Hsien Chi; Nan Yao Lee; Hsin Chun Lee; Chung Lin Chen; Po Lin Chen; Chia Ming Chang; Chi Jung Wu; Nai Ying Ko; Ming Che Tsai; Wen Chien Ko

Necrotizing fasciitis (NF), a rare but severe infection, usually occurs in individuals with underlying chronic illness, but its clinical presentation among cirrhotic patients is infrequently discussed. Forty-two cirrhotic patients with 47 episodes of NF between 1995 and 2006 were analyzed. Their mean age was 55.6 years, with male preponderance (34 patients, 81%). Lower extremities were mainly involved (70%). Of 42 episodes with identified pathogens, 41 (97%) were monomicrobial infections and were caused mainly by Gram-negative rods (GNBs) (32, 76%), including Vibrio (15, 36%), Klebsiella (9, 21%), and Aeromonas spp. (6, 14%). As compared with NF caused by Gram-positive cocci (GPCs), NF caused by GNBs tended to have concurrent bacteremia (81% versus 50%, P=0.09) and initially presented with septic shock (75% versus 30%, P=0.02). However, the in-hospital mortality rate was similar for NF caused by GNBs and GPCs (34% versus 30%, P=1.00). In multivariate analyses, higher sepsis-related organ failure assessment scores (>8) and Child-Pugh class C at initial presentation were independently associated with poor prognoses.


Journal of The Formosan Medical Association | 2008

Seroprevalence of viral hepatitis and sexually transmitted disease among adults with recently diagnosed HIV infection in Southern Taiwan, 2000-2005: upsurge in hepatitis C virus infections among injection drug users.

Hsin-Chun Lee; Nai Ying Ko; Nan Yao Lee; Chia Ming Chang; Wen Chien Ko

BACKGROUND/PURPOSE The purpose of this study was to compare the seroprevalence of viral hepatitis and sexually transmitted disease (STD) co-infections among three populations at risk recently diagnosed with HIV infection. METHODS A retrospective review of medical records was performed to determine the prevalence of several co-infections among adults recently diagnosed with HIV infection between 2000 and 2005 at National Cheng Kung University Hospital in Tainan, Taiwan. RESULTS Among a total of 484 adults, 124 (25.6%) were men having sex with men (MSM), 105 (21.7%) were heterosexual adults, and 255 (52.7%) were injection drug users (IDUs). The case number of adults with recently diagnosed HIV infection increased annually, from 27 in 2000 to 142 in 2005 (p < 0.001). This trend appeared to be attributable to the upsurge in HIV infection among IDUs beginning in 2003. At the time of HIV diagnosis, mean CD4+ counts were significantly higher and plasma HIV-1 RNA loads were lower in the IDU group than the MSM or heterosexual groups. The hepatitis B virus (HBV) carrier rate was similar in all three groups, with an average rate of 16.5%. The prevalence of treponemal antibody and Entamoeba histolytica indirect hemagglutination antibody was higher in MSM (37.5% and 9.4%, respectively) than in heterosexuals (19.6% and 7.3%, respectively) or IDUs (3.2% and 2.1%). The seroprevalence of hepatitis A virus infection increased with age, with 94.2% (97/103) of patients who were older than 40 years. Hepatitis C virus (HCV) or HBV-HCV co-infections were noted more often in IDUs (97.9% and 16.9%, respectively) than in heterosexuals (10.9% and 2.2%, respectively) and MSM (5.3% and 3.6%, respectively). CONCLUSION There was a recent upsurge in HIV-HCV co-infected IDUs in southern Taiwan. A higher rate of co-infection with STDs among HIV-infected MSM highlights the need for integrated STD control efforts in current HIV prevention programs.


Infection | 2008

Community-Acquired Klebsiella pneumoniae Complicated Skin and Soft-Tissue Infections of Extremities: Emphasis on Cirrhotic Patients and Gas Formation

Chia Ming Chang; Hsin-Chun Lee; Nan Yao Lee; I-Wen Lee; Chi-Jung Wu; Po Lin Chen; Ching-Chi Lee; Nai Ying Ko; Wen Chien Ko

Background:Klebsiella pneumoniae was rarely reported to cause complicated skin and soft tissue infections (cSSTIs). Our study was to delineate clinical characteristics and outcome of cSSTIs involving extremities caused by K. pneumoniae.Patients and Methods:Adult patients aged 16 years or more with community-acquired cSSTIs, which involved the extremities and were caused by four common aerobic pathogens at a medical center in southern Taiwan during a 54-month period, were reviewed.Results:Of 76 cases enrolled, Staphylococcus aureus was the most common pathogen (52 cases, 68%), followed by K. pneumoniae (16, 21%), β-hemolytic streptococci (5, 7%), and Escherichia coli (3, 4%). Forty-six (61%) had underlying conditions, and diabetes mellitus was most common among K. pneumoniae and non-K. pneumoniae groups (63% and 45%, respectively). Compared to patients with cSSTIs caused by other bacteria, those with K. pneumoniae cSSTIs were predominantly male, more often had liver cirrhosis, malignant neoplasm and alcoholism. In addition, they were more likely to have fever, shock, bacteremia, gas formation, pyomyositis, metastatic infections, as well as longer durations of hospitalization. Using multivariate analysis, liver cirrhosis (adjusted odds ratio [aOR] 12.5, 95% confidence interval [CI] 2.0–79.1, p = 0.007) and male gender (aOR 11.5, 95% CI 1.1–116.8, p = 0.039) were significantly associated with K. pneumoniae cSSTIs.Conclusions:We highlight the role of K. pneumoniae in Taiwanese patients with cSSTIs involving extremities, and its potential for gas and pus formation, and metastatic infections. Empiric antimicrobial coverage of K. pneumoniae and close monitoring of metastatic infections are mandatory for patients with risk factors.


Sexually Transmitted Diseases | 2006

Prevalence of human immunodeficiency virus and sexually transmitted infections and risky sexual behaviors among men visiting gay bathhouses in taiwan.

Nai Ying Ko; Hsin-Chun Lee; Jui-Ling Chang; Nan Yao Lee; Chia Ming Chang; Meng-Ping Lee; Yi-Hui Lin; Kang-Yen Lai; Wen Chien Ko

Objectives: This study aimed to investigate the prevalence of human immunodeficiency virus (HIV) and sexually transmitted infections (STIs) and predictors of risky sexual behaviors among men visiting gay bathhouses. Study Design: A cross-sectional study was conducted at 8 gay bathhouses in Taiwan. Bathhouse attendees were invited to complete a questionnaire and to be screened for HIV/STIs. Results: Of 451 men recruited for the study, 339 (75%) completed the questionnaire and were screened for HIV/STIs. The study indicated that seroprevalence rates of anti-HIV-1 antibody, specific Treponema pallidum antibodies detected by hemagglutination assay, surface antigen of hepatitis B virus, IgG antibodies for hepatitis A virus, antibody for hepatitis C virus, and indirect hemagglutination antibody for Entamoeba histolytica (serum titer ≥1:128) were 8%, 18%, 16%, 38%, 3%, and 6%, respectively. Prevalence rates for chlamydial and gonococcal infections reflected by nucleic acid amplification tests in urine samples were 7% and 4%, respectively. Irregular use of condoms during oral sex, condom inaccessibility at bathhouses, unprotected sex at public venues, no prior HIV test, and 5 or more visits to bathhouses every month were independently associated with unprotected anal intercourse. Conclusion: Men attending gay bathhouses report engaging in unsafe sex practices and are at substantial risk of acquisition of HIV/STIs. These findings highlight the need for more comprehensive prevention efforts at gay bathhouses.


Journal of Medical Internet Research | 2013

Effects of Internet Popular Opinion Leaders (iPOL) Among Internet-Using Men Who Have Sex With Men

Nai Ying Ko; Chao Hsien Hsieh; Ming Chi Wang; Chiang Lee; Chun-Lin Chen; An Chun Chung; Su Ting Hsu

Background The Internet has become a popular venue for facilitating sex networking for men who have sex with men (MSM). Objective The study aimed to evaluate the effectiveness of Internet popular opinion leaders (iPOL) in disseminating information about the human immunodeficiency virus (HIV), increasing the frequency of HIV testing, and reducing risky behaviors among MSM in Taiwan. Methods A quasi-experimental study with a nonequivalent control website for comparison was used to estimate the effectiveness of iPOL. A community-level intervention, iPOL, was conducted at the Facebook social networking website and at top1069 as a control. The iPOLs actively disseminated HIV-related information via the platform of Internet opinion leaders and AIDS information center, and discussed and responded to questions or replied to Internet-using MSM. Results A total of 369 iPOLs posted 432 articles and 503 replies to others, influencing 959,088 persons on Facebook. A total of 1037 MSM, 552 (53.23%) from an intervention website and 485 (46.76%) from a control website, participated in the follow-up study survey (response rate 96%). At the 6-month follow-up after the intervention was conducted, MSM who visited the intervention website were more likely to receive HIV-related information (25.49% versus 10.47%, P<.001), discuss HIV issues with others (41.88% versus 23.79%, P<.001), review articles about HIV (90.58% versus 79.73%, P<.001), and be asked about or discuss HIV-related questions (51.11% versus 31.78%, P<.001) than those on the control website. In addition, MSM were more likely to have HIV tests within 6 months (43.89% versus 22.31%, P<.001) and consistently use condoms during anal sex with online sex partners than those using the control website (34.15% versus 26.19%, P=.004). Conclusions The study showed the feasibility and effectiveness of the iPOL intervention as an online HIV prevention program. These findings underscore the importance of disseminating HIV information online, as well as the challenges inherent in the efforts of iPOL to reduce HIV-related risky behaviors among Internet-using MSM.


Journal of Infection | 2010

Clinical manifestations, antimicrobial therapy, and prognostic factors of monomicrobial Acinetobacter baumannii complex bacteremia

Nan Yao Lee; Tsung Chain Chang; Chi Jung Wu; Chia Ming Chang; Hsin Chun Lee; Po Lin Chen; Ching Chi Lee; Nai Ying Ko; Wen Chien Ko

OBJECTIVES Bacteremia due to Acinetobacter baumannii complex (ABC), which composed of four genomic species (gen. sp.), is a serious and potentially fatal condition. The epidemiology and outcome of such infections due to individual gen. sp. remain undefined. METHODS A retrospective study of patients with monomicrobial ABC bacteremia over six years was conducted at a medical center to determine the association of gen. sp. with clinical outcome. RESULTS Included were 291 patients with monomicrobial ABC bacteremia. Of them, 222 (76.3%) patients had bacteremia caused by gen. sp. 2, i.e. A. baumannii. The presence of multidrug-resistant phenotype was the only independent predictor of Acinetobacter gen. sp. 2 bacteremia (adjusted odd ratio, 7.5; 95% confidence interval, 3.8-14.7; P < 0.001). Patients with Acinetobacter gen. sp. 2 bacteremia had a higher sepsis-related (P = 0.006) and 30 day (P = 0.028) mortality rates than the non-Acinetobacter gen. sp. 2 group. The fatal outcome was independently associated with high SPAS II scores (P = 0.002), rapidly fatal underlying diseases (P = 0.002), bacteremia caused by Acinetobacter gen. sp. 2 (P = 0.01), inappropriate definitive antimicrobial therapy (P < 0.001), and severe sepsis (P < 0.001). CONCLUSION Acinetobacter gen. sp. 2 bacteremia heralded a worse clinical outcome, and therefore the gen. sp. identification of ABC bacteremic isolates is justified.


Antimicrobial Agents and Chemotherapy | 2010

Bacteremia Due to Extended-Spectrum-β-Lactamase-Producing Enterobacter cloacae: Role of Carbapenem Therapy

Ching-Chi Lee; Nan Yao Lee; Jing-Jou Yan; Hsin-Chun Lee; Po Lin Chen; Chia Ming Chang; Chi-Jung Wu; Nai Ying Ko; Li-Rong Wang; Chih Hsien Chi; Wen Chien Ko

ABSTRACT Enterobacter cloacae is an important nosocomial pathogen. However, few studies specifically dealing with the clinical characteristics and outcome of extended-spectrum β-lactamase (ESBL)-producing E. cloacae infections have been published. During an 8-year period in a medical center, of 610 E. cloacae bacteremic isolates, 138 (22.6%) with ESBL genes were designated the ESBL group, and 120 (19.6%) cefotaxime-nonsusceptible isolates without the ESBL phenotype and genes were designated the control group. Of the former group of isolates, 133 (96.3%) carried the blaSHV-12 gene, 3 (2.1%) had blaCTX-M3, and 2 (1.4%) had both the blaSHV-12 and blaCTX-M3 genes. After patients under the age of 18 years were excluded, there were 206 adults with E. cloacae bacteremia, and these consisted of 121 patients in the ESBL group and 85 in the control group. More episodes of hospital-onset and polymicrobial bacteremia, increased severity of illness, more cases of bacteremia onset in intensive care units (ICUs), and longer stays in the hospital and ICU after bacteremia onset were noted in the ESBL group. However, the crude and sepsis-related mortality rates in two groups were similar. Of the ESBL group, the in-hospital sepsis-related mortality rate of patients definitively treated by a carbapenem was lower than that of those treated by noncarbapenem β-lactams (5/53, or 9.4%, versus 13/44, or 29.5%; P = 0.01) though the difference was not significant in the hierarchical multivariate analysis (P = 0.46). Among 62 patients with follow-up blood cultures within 14 days of bacteremia onset, breakthrough bacteremia was more common in those treated by a noncarbapenem β-lactam agent than in those treated by a carbapenem (18/31, or 58.0%, versus 3/31, or 9.6%; P < 0.001). Thus, carbapenem therapy for ESBL-producing E. cloacae that cause bacteremia may provide therapeutic benefits.


Aids Care-psychological and Socio-medical Aspects of Aids\/hiv | 2009

Effects of structural intervention on increasing condom availability and reducing risky sexual behaviours in gay bathhouse attendees

Nai Ying Ko; Hsin-Chun Lee; Chien-Ching Hung; Jui-Ling Chang; Nan Yao Lee; Chia Ming Chang; Meng-Ping Lee; Hsu-Ting Chang; Wen Chien Ko

Abstract The study purpose was to evaluate the effectiveness of a structural intervention in reducing unprotected sexual behaviours, increasing condom accessibility and their relationship to the prevalence of HIV infection and sexually transmitted infections (STIs) in gay bathhouse attendees. A quasi-experimental study with a non-equivalent control group for comparison was conducted at nine gay bathhouses in Taiwan from 2004 to 2006. A structural intervention designed to increase condom distribution and accessibility inside the bathhouses was implemented at one bathhouse in each city. Bathhouse attendees were invited to complete a questionnaire and to be screened for HIV infection and STIs. Of 632 study participants, 270 were surveyed six months after the intervention was conducted. At the time of follow-up after controlling for baseline data, patrons attending bathhouses for which intervention was performed were more likely to report accessing condoms inside bathhouses than those attending control bathhouses (92.6% versus 81.3%, P = 0.016), and condoms were more likely to be available at the reception desk of the bathhouse entrance (87.5% in intervention bathhouses versus 69.4% in control, P = 0.047). In a multivariate analysis adjusted for age, access to condoms inside bathhouses (adjusted odds ratio (AOR): 4.35; 95% confidence interval (CI): 1.48–12.78) and attendance at bathhouses with intervention (AOR: 2.07; 95% CI: 1.07–3.97) were independently associated with consistent condom use during anal intercourse. There were no significant differences in the prevalences of HIV infection and STIs at the six-month follow-up. Bathhouses with structural intervention were associated with consistent condom use during anal intercourse among bathhouse patrons. Our findings highlight the importance of extension of condom distribution inside the bathhouses to increase condom use among bathhouse patrons.

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Wen Chien Ko

National Cheng Kung University

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Nan Yao Lee

National Cheng Kung University

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Chia Ming Chang

National Cheng Kung University

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Hsin Chun Lee

National Cheng Kung University

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Hsin-Chun Lee

National Cheng Kung University

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Po Lin Chen

National Cheng Kung University

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Hsiao Ying Liu

National Cheng Kung University

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Yen Chin Chen

National Cheng Kung University

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Chi Jung Wu

National Cheng Kung University

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Yi Yin Lai

National Cheng Kung University

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