Y.-T. Huang

Diagnostic performance of an enzyme-linked immunospot assay for interferon-γ in extrapulmonary tuberculosis varies between different sites of disease.

OBJECTIVES To evaluate diagnostic performance of an enzyme-linked immunospot assay for interferon-gamma (T SPOT-TB) in patients with suspected extrapulmonary tuberculosis (TB). METHODS From January 2007 to December 2008, patients with suspected extrapulmonary TB were prospectively enrolled from 2 tertiary care hospitals. RESULTS A total of 138 patients with suspected extrapulmonary TB were enrolled; 50 patients had positive culture for Mycobacterium tuberculosis and 39 patients had probable TB. The sites of infection were lymph node (n = 20), pleura (n = 19), bone/joint (n = 15), urinary tract (n = 7), peritoneum (n = 7), meninges (n = 6), disseminated (n = 5), intestine (n = 3), pericardium (n = 2), skin (n = 2), throat (n = 1), neck (n = 1), and genitalia (n = 1). The overall sensitivity and specificity were 79.8% (71/89) and 81.6% (40/49). The sensitivity ranged from 100% for tuberculous meningitis, tuberculous pericarditis, and intestinal TB, 95% for lymphadenitis, to 42.9% for tuberculous peritonitis. The sensitivity of the T SPOT-TB assay was 70.6% in immunocompromised patients and 85.5% in immunocompetent patients (p = 0.09). CONCLUSIONS The T SPOT-TB assay can be a useful tool for diagnosing extra-pulmonary TB in immunocompetent and immunocompromised patients, particularly for tuberculous meningitis, pericarditis, lymphadenitis, and intestinal TB.

Sentinel Hospital Surveillance for Rotavirus Diarrhea in Taiwan, 2001–2003

We examined the epidemiological profile of rotavirus infection among children hospitalized for diarrhea in Taiwan, to assess the burden of this disease. From 1 April 2001 through 31 March 2003, children <5 years old with gastroenteritis admitted to 4 sentinel hospitals were enrolled in a surveillance study and had stool specimens tested for the presence of rotavirus, enteric adenovirus, and the bacterial pathogens for which routine screening is performed. For 52% of patients, a recognized enteric pathogen was identified, including rotavirus (43% of patients), bacteria (11%), enteric adenovirus (2.5%), and a mixture of pathogens (3.9%). Rotavirus was detected year-round, but great month-to-month variability made it difficult to identify a distinct seasonal pattern. Rotavirus disease was most common among children 7-23 months old, but the rate of rotavirus detection varied little between the youngest and oldest age groups. The novel strain P[8]G9 was detected most commonly (37% of strains), followed by strains P[8]G1 (31%), P[4]G2 (10%), P[8]G3 (9.3%), and P[8]G4 (3.7%). Rotavirus infection is the most important cause of diarrhea among hospitalized children in Taiwan, and a rotavirus vaccination program for young children might significantly reduce this problem.

Catheter-related bacteraemia and infective endocarditis caused by Kocuria species

We describe five patients with positive blood culture for Kocuria species. Three patients had catheter-related bacteraemia and one had infective endocarditis caused by Kocuria kristinae, and one had a K. marina isolate, which was considered to be a contaminant. Identification of the isolates was further confirmed by 16S rRNA gene sequence analysis. In conclusion, Kocuria species are an unusual cause of infection in immunocompromised patients. Accurate identification with molecular methods is imperative for the diagnosis of these unusual pathogens.

Clinical and microbiological characteristics of infections caused by various Nocardia species in Taiwan: a multicenter study from 1998 to 2010

This multicenter study in Taiwan investigated the clinical presentations of various Nocardia species infections based on 16S rRNA sequence analysis. Patients with nocardiosis in four large medical centers from 1998 to 2010 were included. A total of 100 preserved nonduplicate isolates causing human infection were identified as Nocardia species. Sequencing analysis of 16S rRNA confirmed that 35 of 36 N. asteroides isolates identified by conventional tests were non-asteroides Nocardia species, and that two of 50 N. brasiliensis isolates had also been initially misidentified. N. brasiliensis (50%) was the most common pathogen, followed by N. cyriacigeorgica (18%). In addition, several rare pathogens were identified, including N. asiatica, N. rhamnosiphila, N. abscessus, N. transvalensis, N. elegans, and N. carnea. Primary cutaneous infection was the most common presentation, noted in 55 (55%) patients, while pulmonary infection presented in 26 (26%) patients. The crude mortality rate was 6.7% (6/89), and was lowest for primary cutaneous infection (2.2%) and highest for disseminated disease and pulmonary infection (16.7%). In conclusion, N. brasiliensis and N. cyriacigeorgica were the most common pathogens causing nocardiosis in Taiwan. Molecular methods for identifying Nocardia to the species level are mandatory for better understanding the epidemiology and clinical characteristics of patients with nocardiosis.

Skin and soft-tissue infection caused by non-tuberculous mycobacteria in Taiwan, 1997-2008.

The aim of this study was to investigate the clinical, microbiological, and pathological characteristics and the outcomes of skin and soft-tissue infection (SSTI) caused by non-tuberculous mycobacteria (NTM). Medical records of 50 patients with SSTI caused by NTM identified from 2005 to 2008 and 63 patients previously reported in a medical centre from 1997 to 2004 were reviewed. The annual incidence (per 100,000 outpatients and in-patients) ranged from 0·57 in 2005, 0·38 in 2007, to 1·1 in 2008, with an average of 0·62/100,000. From 1997 to 2008, the average incidence was 1·39/100,000 patients. The average annual incidence of SSTI caused by NTM was 0·62/100,000 outpatients and in-patients during 2005 and 2008. Of the total of 113 patients identified during the 12-year period, patients infected with Mycobacterium fortuitum and M. marinum were younger than those infected with M. avium-intracellulare complex (MAC) (36 and 44 years vs. 55 years, P=0·004 and P=0·056, respectively), and were more likely to have previous invasive procedures than those infected with MAC and M. abscessus (81·8% and 72·0% vs. 27·8% and 54·8%, P=0·007), and less likely to have associated immunosuppression (9·1% and 24% vs. 66·7% and 45·2%, P=0·006). Granuloma was more often observed in immunocompetent patients (60·1% vs. 40%, P=0·019), and in M. marinum-infected specimens (78·3%). There were significant differences in the demographic and clinical features of patients with NTM SSTI, including immunosuppression, trauma experience, and depth of tissue infections.

Bacteraemia caused by Weissella confusa at a university hospital in Taiwan, 1997-2007

Human infections caused by Weissella confusa are rarely reported. Ten patients with bacteraemia caused by W. confusa who were treated at a tertiary-care hospital in Taiwan during 1997-2007 were studied. All isolates were initially misidentified as various Lactobacillus and Leuconostoc species by two commercial automated identification methods, and were confirmed to be W. confusa by 16S rRNA sequencing analysis. MICs of these isolates for ten antimicrobial agents were determined by the agar dilution method. The characteristics of these patients included underlying malignancy (n = 4), presence of a central catheter (n = 6), surgery within the previous 3 months (n = 4) and concomitant polymicrobial bacteraemia (n = 5, 50%). Mortality was directly attributed to bacteraemia in two patients. All isolates exhibited high trimethoprim-sulphamethoxazole and ceftazidime MICs (≥ 128 mg/L) and were inhibited by linezolid, daptomycin, ceftobiprole and tigecycline at 4, 0.12, 2 and 0.12 mg/L, respectively. In conclusion, W. confusa should be included in the list of organisms causing bacteraemia in immunocompromised hosts. Novel antibiotics, including daptomycin, moxifloxacin, doripenem and tigecycline, exert good activity against W. confusa.

Correlation between antimicrobial consumption and resistance among Staphylococcus aureus and enterococci causing healthcare-associated infections at a university hospital in Taiwan from 2000 to 2009

This study investigated the correlation between antibiotic consumption and resistance among Staphylococcus aureus and enterococci causing healthcare-associated infections at a university hospital in Taiwan from 2000 to 2009. Overall, the trend of total consumption (defined daily dose [DDD] per 1,000 patient-days) of glycopeptides, including vancomycin and teicoplanin, significantly increased during 2000 to 2003 and remained stable during 2004–2009. Vancomycin consumption significantly increased during 2003 and decreased after 2004. A significant decrease in the resistance rate with time was found for oxacillin- and gentamicin-resistant S. aureus. In contrast, the rates of vancomycin- and teicoplanin-resistant enterocci increased significantly. A significant correlation was found between the increased use of extended-spectrum cephalosporins, β-lactam-β-lactamase inhibitor combinations, carbapenems and the decreased prevalence of methicillin-resistant S. aureus (MRSA). In contrast, the increased use of teicoplanin, extended-spectrum cephalosporins, β-lactam-β-lactamase inhibitor combinations, and carbapenems was correlated with the increased prevalence of vancomycin-resistant enterococci (VRE). In conclusion, this 10-year study in a single institution identified different correlations between the prescription of antibiotics and the resistance rates of MRSA and VRE. Strict implementation of infection control policy based on these correlates would be helpful in decreasing the presence of these multidrug-resistant pathogens in hospitals.

Healthcare-associated bacteraemia caused by Leuconostoc species at a university hospital in Taiwan between 1995 and 2008

We studied twenty patients with Leuconostoc spp. bacteraemia at a tertiary hospital in northern Taiwan between 1995 and 2008. All isolates were identified to species level using conventional and commercial automated methods in conjunction with 16S rRNA sequencing analysis. Leuconostoc lactis (15/20, 75%) constituted the most common species but required molecular methods for accurate identification. Minimum inhibitory concentrations (MICs) of 10 antimicrobial agents were determined using the broth microdilution method. Among these 20 patients, 19 had healthcare-associated Leuconostoc spp. bacteraemia and 11 patients (55%) had underlying malignancies. Eleven had been hospitalised for more than 30 days (median: 32.5 days; range: 0-252 days) before the bacteraemic episode. At the time of bacteraemia, 11 had a Pitt bacteraemia score of ≥ 4 (median: 4; range: 0-7) and 12 had a modified Acute Physiological Assessment and Chronic Health Evaluation (APACHE II) score of ≥ 20 (median: 22; range: 5-37). Azithromycin (MIC: 0.12 μg/mL), moxifloxacin (MIC: 0.25-0.5 μg/mL), daptomycin (MIC: 0.03-0.25 μg/mL) and tigecycline (MIC: 0.06-0.12 μg/mL) exhibited good in vitro activity against Leuconostoc spp. although bacteraemia due to L. lactis was associated with high mortality in immunocompromised patients.

Culture-positive invasive aspergillosis in a medical center in Taiwan, 2000–2009

We reviewed 776 patients who were culture positive for Aspergillus species at the hospital from 2000 to 2009. The isolates were collected for species identification by oligonucleotide hybridization and sequence analysis. A total of 96 cases of proven or probable IA were identified according to published criteria. The incidence of IA has increased significantly during the study period. Aspergillus fumigatus and A. flavus (41.7% each) were equally prevalent causative species. IA due to unusual species including A. nidulans (n = 2), A. versicolor (n = 2), and A. tubingensis (n = 1) were also found. Among patients with IA, 55.2% had hematological disorder, 19.8% had underlying lung disorder, and 10.4% had autoimmune disease. The isolates species (P < 0.001) and underlying disease (P < 0.001) significantly affect the association of a positive culture with invasive disease. The overall mortality at three months was 62.5%, which remained stable throughout the study period. Multivariate analysis identified prior steroid use (P = 0.007) as a significant risk factor for death, while surgery (P = 0.030) and voriconazole (P = 0.012) had protective effects. In conclusion, autoimmune disorders and underlying pulmonary diseases should also be considered as important predisposing factors of IA. Further emphasis on surgery and voriconazole in the management of IA might be beneficial.

Diagnostic performance of an enzyme-linked immunospot assay for interferon-γ in skeletal tuberculosis

The aim of this study was to evaluate the diagnostic performance of an enzyme-linked immunospot (ELISPOT) assay for interferon-γ in patients with suspected skeletal tuberculosis (TB). From March 2007 to June 2010, a total of 36 patients with suspected skeletal TB in a tertiary care hospital in Taiwan were enrolled. Twelve patients (35.3%) had culture-confirmed TB, three (8.8%) patients had probable TB, and the remaining 21 (58.3%) patients did not have TB. Fourteen patients with mycobacterial infection had available biopsy or surgical specimens for histopathological examination and 12 (85.7%) specimens had pathological features consistent with mycobacterial infection. Among the 12 patients with positive findings indicating mycobacterial infection, all seven patients with spinal TB and three of five patients with TB arthritis had positive ELISPOT assays. All nine patients with spinal TB had positive ELISPOT assays, but only four of six patients with TB arthritis had positive ELISPOT assays. The sensitivity, specificity, positive predictive value, and negative predictive value for skeletal TB diagnosis by the ELISPOT assay were 86.7%, 61.9%, 61.9%, and 86.7%, respectively. In conclusion, the ELISPOT assay can provide useful support in diagnosing skeletal TB, and spinal TB can be excluded based on a negative ELISPOT assay.