Yung-Ching Liu

Correlation between Pyrazinamide Activity and pncA Mutations in Mycobacterium tuberculosis Isolates in Taiwan

ABSTRACT A total of 76 clinical Mycobacterium tuberculosis isolates from Taiwan were tested for pyrazinamidase activity, pyrazinamide susceptibility, and pncA mutations. Frequency of resistance to PZA rose with increases in resistance to first-line drugs. Of 17 pyrazinamide-resistant strains, 7 (3 of which had not been previously described) possessed mutations in the pncA gene.

Efficacy of point-of-entry copper–silver ionisation system in eradicating Legionella pneumophila in a tropical tertiary care hospital: implications for hospitals contaminated with Legionella in both hot and cold water

A medical centre in Southern Taiwan experienced an outbreak of nosocomial Legionnaires disease, with the water distribution system thought to be the source of the infection. Even after two superheats and flush, the rate of Legionella positivity in distal sites in hospital wards and intensive care units (ICUs) was 14% and 66%, respectively. Copper-silver ionisation was therefore implemented in an attempt to control Legionella colonisation in both hot- and cold-water systems. Environmental cultures and ion concentration testing were performed to evaluate the efficacy of ionisation. When the system was activated, no significant change in rate of Legionella positivity in the hospital wards (20% vs baseline of 30%) and ICUs (28% vs baseline of 34%) of the test buildings over a three-month period was found, although all Legionella positivity rates were below 30%, an arbitrary target for Legionnaires disease prevention. When ion concentrations were increased from month 4 to month 7, however, the rate of Legionella positivity decreased significantly to 5% (mean) in hospital wards (P=0.037) and 16% (mean) in ICUs (P=0.037). Legionella positivity was further reduced to 0% in hospital wards and 5% (mean) in ICUs while 50% sites were still positive for Legionella in a control building. Although Legionella was not completely eradicated during the study period, no culture- or urine-confirmed hospital-acquired Legionnaires disease was reported. Ionisation was effective in controlling Legionella for both hot and cold water, and may be an attractive alternative as a point-of-entry systematic disinfection solution for Legionella.

Using an integrated infection control strategy during outbreak control to minimize nosocomial infection of severe acute respiratory syndrome among healthcare workers.

n Summaryn n Healthcare workers (HCWs) are at risk of acquiring severe acute respiratory syndrome (SARS) while caring for SARS patients. Personal protective equipment and negative pressure isolation rooms (NPIRs) have not been completely successful in protecting HCWs. We introduced an innovative, integrated infection control strategy involving triaging patients using barriers, zones of risk, and extensive installation of alcohol dispensers for glove-on hand rubbing. This integrated infection control approach was implemented at a SARS designated hospital (‘study hospital’) where NPIRs were not available. The number of HCWs who contracted SARS in the study hospital was compared with the number of HCWs who contracted SARS in 86 Taiwan hospitals that did not use the integrated infection control strategy. Two HCWs contracted SARS in the study hospital (0.03 cases/bed) compared with 93 HCWs in the other hospitals (0.13 cases/bed) during the same three-week period. Our strategy appeared to be effective in reducing the incidence of HCWs contracting SARS. The advantages included rapid implementation without NPIRs, flexibility to transfer patients, and re-inforcement for HCWs to comply with infection control procedures, especially handwashing. The efficacy and low cost are major advantages, especially in countries with large populations at risk and fewer economic resources.n n

Rapid detection of pulmonary tuberculosis using the BDProbeTEC ET Mycobacterium tuberculosis Complex Direct Detection Assay (DTB).

The ability to rapidly detect tubercle bacilli in respiratory secretions was determined for the BDProbeTEC ET Mycobacterium tuberculosis Complex Direct Detection Assay in comparison with the acid-fast smear (AFS). A total of 267 respiratory specimens obtained from 89 patients were evaluated. The DTB assay was positive in 70 of 78 culture positive specimens (89.7%) and 12 of 177 culture negative specimens (6.8%). The AFS was positive in 33 of 78 culture positive specimens (42.3%) and 3 of 186 culture negative specimens (1.6%). The sensitivity, specificity, positive predictive value, and negative predictive value of DTB assay were 89.7%, 93.7%, 85.4%, and 95.7%, respectively. The sensitivity of a single DBT (74.4%) was 2.1-times greater than three AFS (35.9%). The greater cost of the DTB assay compared to the AFS was compensated by its valuable information for the diagnosis and control of tuberculosis. These results demonstrated the clinical usefulness of the DTB assay for the rapid diagnosis of tuberculosis in respiratory specimens.

Taiwan's traffic control bundle and the elimination of nosocomial severe acute respiratory syndrome among healthcare workers

n Summaryn n The traffic control bundle consists of procedures designed to help prevent epidemic nosocomial infection. We retrospectively studied the serial infection control measures to determine factors most effective in preventing nosocomial infections of healthcare workers (HCWs) during the 2003 Taiwanese severe acute respiratory syndrome (SARS) epidemic. Fever screening stations, triage of fever patients, separating SARS patients from other patients, separation of entrances and passageways between patients and HCWs, and increasing hand-washing facilities all demonstrated a protective effect for HCWs (univariate analysis; Pn <0.05). By multiple logistic regression: (i) checkpoint alcohol dispensers for glove-on hand rubbing between zones of risk, and (ii) fever screening at the fever screen station outside the emergency department, were the significant methods effectively minimising nosocomial SARS infection of HCWs (Pn <0.05). The traffic control bundle should be implemented in future epidemics as a tool to achieve strict infection control measures.n n

Liver Abscess Caused by an Infected Ventriculoperitoneal Shunt

Pyogenic liver abscess in Taiwan is most commonly due to Klebsiella pneumoniae infection in diabetic patients, and less frequently due to biliary tract infections. Liver abscess caused by ventriculoperitoneal (VP) shunt is very rare. We report a case of liver abscess caused by methicillin-resistant Staphylococcus aureus (MRSA), which developed as a complication of an infected VP shunt. A 53-year-old woman, who had shad a VP shunt implanted 3 months previously for hydrocephalus due to intracranial hemorrhage, presented with fever off and on, drowsiness and seizure attacks for 1 week. Computed tomography (CT) of the brain showed only mild right-sided hydrocephalus, and was negative for intracranial hemorrhage and intracranial mass. Analysis of cerebrospinal fluid showed significant pleocytosis and hypoglycorrhachia. CT scan of the abdomen disclosed a huge abscess in the right lobe of the liver. Cultures of both the cerebrospinal fluid and aspirated liver abscess isolated MRSA. The patient was treated with intraventricular and intravenous vancomycin, intravenous teicoplanin and oral rifampicin, followed by oral chloramphenicol and rifampicin. Percutaneous drainage of the liver abscess and externalization of the VP shunt were performed. The liver abscess had resolved almost completely on ultrasonography after 2 weeks of therapy. Liver abscess in patients with a VP shunt should be considered a possible abdominal complication of the VP shunt, and may be caused by unusual pathogens. Diagnosis requires CT scan and direct aspiration and culture of the liver abscess. Treatment requires management of both the liver abscess and the infected shunt.

Combination of molecular assay and clinical evaluation for early confirmation of tuberculosis cases

The cost-effectiveness of the ProbeTec ET Direct TB assay (DTB) was compared with that of culture for detection of Mycobacterium tuberculosis complex in 361 acid-fast stain-positive respiratory specimens. The overall sensitivity, specificity, positive predictive value and negative predictive value of DTB were 97.7%, 86.6%, 87.2% and 97.6%, respectively. When clinical evaluation was added to DTB, the specificity and positive predictive value of DTB increased to 94.7% and 95.4%, respectively. Treatment costs of

Comparison of the AMPLICOR MYCOBACTERIUM Test with Microscopy and Culture for Diagnosis of Pulmonary Tuberculosis

133,521 would have been saved in this cohort if DTB, instead of culture results, had been used to eliminate false-positive smear results.

Clinical Experience with Multidrug-Resistant Tuberculosis in a TB Referral Hospital

Tuberculosis (TB) is one of the major public health problems in Taiwan. Effective control of TB depends on rapid and correct diagnosis and appropriate treatment. The aim of this study was to evaluate the performance of the Roche AMPLICOR MYCOBACTERIUM (AMPLICOR MTB) test compared with microscopy and culture for diagnosis of pulmonary TB. A total of 123 specimens obtained from 90 suspected pulmonary TB patients were included in this study. All specimens were processed, stained, cultured and assayed using the AMPLICOR MTB test for identification of M. tuberculosis. All patients were followed up for 1 year to confirm or exclude the diagnosis of pulmonary TB. M. tuberculosis was isolated from 29 of these specimens, and final diagnosis of pulmonary TB was identified in 50 patients according to clinical discrepancies. On initial testing, the sensitivity, specificity, positive and negative predictive values of the AMPLICOR MTB test, compared with cultures, were 75.9, 84, 59.5, and 91.9%, respectively. After resolution of discrepancies by the final clinical diagnosis, the sensitivity, specificity, positive and negative predictive values were 72, 98.6, 97.3, and 83.7%, respectively. For smear-positive specimens, the sensitivity was 84.9%, for smear-negative specimens, the sensitivity was 47.1%. Our study demonstrated that the use of the AMPLICOR MTB test was highly sensitive and specific for rapid diagnosis of pulmonary TB. Further studies are needed to determine the cost-effective use of this test with smear-negative specimens.

Mycotic aneurysm due to non-typhi salmonella: report of 16 cases.

Objective: To analyze the outcome and clinical manifestations of patients with multidrug-resistant tuberculosis (MDR- TB) in a regional TB referral center.Methods: From November 1999 through October 2001, all isolates of Mycobacterium tuberculosis with drug resistance were identified via a retrospec-tive review of our mycobacteriolo-gical rereview of our mycobacteriolo-gical records. The medical records of patients with culture proven drug- resistant TB were retrospectively analyzed. MDR-TB was defined as resistance to at least isoniazid and rifampin in vitro. The identification of TB was performed using Mycobacteria growth indicator tube (MGIT) 960 system and drug sensitivity was done by the agar proportional method with a commercial plate.Results: From November 1999 through October 2001, a total of 410 isolates through October 2001, a total of 410 isolates of M. tuberculosis from 408 patients were cultured (408 sputum, 1 pus, 1 pleural effusion). The drug resistance rate of isoniazid was 2.5%, rifampin 10.5%, ethambutol 9%, kanamycin 5.4%, ofloxacin 4.1%, and MDR-TB was 8.3%. The charts of 20 patients with MDR-TB were reviewed. The most common clinical symptoms were cough (85%), dyspnea (70%) and sputum production (65%). The most frequent laboratory findings were most frequent laboratory findings were anemia (45%) and hypoalbuminemia (45%). A mean number of 5 drugs (range 1 to 7) were given for treatment during the course. Culture became negative in 9 patients after a mean of 4.2 months (treatment range 2 to 8). The overall success rate of treatment was 40%. Four patients died. Variables independently associated with an adverse outcomes included the number of drugs to which the TB isolate was resistant (2.9±0.8 v.s. 4.2±1.1, p=0.012) and the number of drugs used for chemotherapy (6.6±0.7 vs 3.4±1.9; p＜0.001). Drug resistant TB was not suspected at initial presentation in 50% of the patients and 3 patients were diagnosed postmortem.Conclusions: Most patients with MDR-TB in this regional referral hospital were inappropriately treated. When appropriate and intensive treatment regimens were used, most patients with MDR-TB can be cured. Hence, if control and eradication of TB is to be achieved, education of patients and doctors in the early recognition and treatment of MDR-TB in this high TB prevalent area is of utmost importance.