Identification of subclinical transmission of vancomycin-resistant enterococcus within an intensive care unit in Taiwan.

BACKGROUND/PURPOSE: Colonization, infection, and clonal dissemination of vancomycin-resistant enterococcus (VRE) have been reported in the literature. We aimed to investigate the incidence rate of VRE acquisition and route of transmission of VRE within the medical intensive care unit (ICU) to prove whether subclinical transmission occurs in medical ICUs. METHODS: Between March 1, 2012 and September 30, 2013, rectal cultures were obtained from all inpatients on admission and after admission to medical ICU. Strain types of VRE were determined by both multilocus sequence typing and pulsed-field gel electrophoresis. RESULTS: A total of 66 of the 405 rectal swab surveillance cultures obtained from 46 inpatients were positive for VRE, among which 27 inpatients were culture-positive for VRE on admission to medical ICU, and 19 inpatients were initially culture-negative but converted to culture-positive after admission. All isolates carried vanA gene consisting of 51 Enterococcus gallinarum, 13 Enterococcus faecium, and two Eenterococcus casseliflavus. Of the 51 E. gallinarum isolates, 40 were type ST 341, seven were ST 252, two were ST 78, and two were ST 64. The Enterococcus spp., MLST and PFGE subtypes were almost similar among these two groups of inpatients. Linezolid and tigecycline were most active against VRE in vitro. CONCLUSION: Subclinical VRE cross transmission may occur in ICU. Active surveillance and maximal barrier precautions of VRE are required at ICU with high colonization rate of VRE and shall be beneficial.

Risk factors of mortality and comparative in-vitro efficacy of anidulafungin, caspofungin, and micafungin for candidemia.

BACKGROUND: Although echinocandins have high in vitro antifungal efficacy according to prior reports, comparative studies on the clinical cure rates of anidulafungin, caspofungin, and micafungin in systemic candida infections have not yet been reported. METHODS: Interpretation of clinical and microbiological responses to anidulafungin, caspofungin, and micafungin in 109 cases of candidemia was done according to the published criteria. The clinical cure rates between patients treated with echinocandins and patients treated with fluconazole were also compared. The minimal inhibitory concentrations (MICs) of anidulafungin, caspofungin, micafungin, and fluconazole for these 109 blood isolates of candida were determined with the Clinical and Laboratory Standards Institute M27-A reference microdilution method. Logistic regression with forward selection was used to determine the important factors of prognosis with variables such as age, underlying diseases, acute physiology and chronic health evaluation (APACHE) III score, persistent candidemia, and antimicrobial therapy. RESULTS: Among the 109 cases of candidemia, 70 were treated with echinocandins, azoles, or amphotericin B for ≥7 days. The clinical cure rate of cases treated with antifungal agents adequately (≥7 days) and inadequately (<7 days) were 44/70 (62.9%) and 4/39 (10.2%), respectively, with significant difference (p < 0.0001). Clinical cure rates of anidulafungin, caspofungin, micafungin, and fluconazole were 18/30 (60.0%), 8/9 (88.9%), 5/7 (71.4%), and 9/18 (50%), respectively. The difference in APACHE III score between treatment success and failure cases was significant. The MIC50/MIC90 of anidulafungin, caspofungin, and micafungin for all Candida spp. were 0.03/1 µg/mL, 0.06/0.5 µg/mL, and 0.008/1 µg/mL, respectively. CONCLUSION: Adequate antifungal therapy and APACHE III score are both independent factors affecting the clinical outcome. The clinical cure rate of the echinocandins group was higher than that of the fluconazole group without significant difference. Although caspofungin had the best clinical cure rate in this study, there was no significant difference between the clinical cure rates among these three echinocandins. All Candida spp. were susceptible in vitro to these three echinocandins.

Surface phonon polariton responses of hexagonal sapphire crystals with non-polar and semi-polar crystallographic planes.

The surface phonon polariton (SPhP) characteristics of hexagonal sapphire crystals with non-polar and semi-polar crystallographic planes are investigated. A formulation that considers the effects of crystal orientation is employed to calculate the SPhP dispersion curves of the samples. The SPhP dispersion curves indicate that the SPhP responses of sapphire crystals in non-polar and semi-polar orientations are directionally sensitive. Resonance frequencies and spectral strengths of the SPhP modes can be modulated simply by tuning the angular positions of the samples. The validity of the theoretical results is confirmed by the polarized infrared attenuated total reflection measurements.

Identification of vancomycin-resistant enterococci clones and inter-hospital spread during an outbreak in Taiwan.

BACKGROUND: In 2003, nosocomial infections caused by vancomycin-resistant enterococci (VRE) occurred rarely in Taiwan. Between 2003 and 2010, however, the average prevalence of vancomycin resistance among enterococci spp. increased from 2% to 16% in community hospitals and from 3% to 21% in medical centers of Taiwan. We used molecular methods to investigate the epidemiology of VRE in a tertiary teaching hospital in Taiwan. METHODS: Between February 2009 and February 2011, rectal samples and infection site specimens were collected from all inpatients in the nephrology ward after patient consent was obtained. VRE strain types were determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). RESULTS: A total of 59 vanA gene-containing VRE isolates (1 per patient) were obtained; 24 originated from rectal sample surveillance of patients who exhibited no symptoms (22 Enterococcus faecium and 2 Enterococcus faecalis), and 35 had developed infections over 3 days after admission (32 E. faecium, 2 E. faecalis, and 1 Enterococcus durans). The 59 VRE isolates demonstrated vancomycin minimum inhibitory concentrations (MICs) of ≥256 µg/m. The MIC range for linezolid, tigecycline, and daptomycin was 0.25-1.5 µg/mL, 0.032-0.25 and 1-4 µg/mL, respectively. For 56 isolates, the MIC for teicoplanin was >8 µg/mL. The predominant types in the nephrology ward were MLST types 414, 78, and18 as well as PFGE types A, C, and D. CONCLUSION: VREs are endemic in nephrology wards. MLST 414 is the most predominant strain. The increase VRE prevalence is due to cross-transmission of VRE clones ST 414,78,18 by undetected VRE carriers. Because similar VRE STs had been reported in a different hospital of Taiwan, this finding may indicate inter-hospital VRE spread in Taiwan. Active surveillance and effective infection control policies are important controlling the spread of VRE in high risk hospital zones. All endemic VRE strains are resistant to teicoplanin but are sensitive to daptomycin, linezolid, and tigecycline.

Clinical features and risk factors of mortality for bacteremia due to community-onset healthcare-associated methicillin-resistant S. aureus.

Studies comparing adult community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and community-onset healthcare-associated MRSA (COHCA MRSA bacteremia have not been available. From 1 January 2010 through 30 October 2010, a prospective observational program was conducted among all patients aged >16 years with positive Staphylococcus aureus blood cultures within 48 h after their arrival at the emergency department of our hospital. Clinical course of infection and infection foci of bacteremia were evaluated. Resistance to oxacillin was confirmed with the presence of mecA gene examined by polymerase chain reaction. Presence of TSST-1, PVL gene, SCCmec elements (I-V), mecA gene, and multilocus sequence typing were identified through methods described elsewhere. Univariate and multivariate analysis revealed that chronic renal failure was significantly more common in COHCA-MRSA than in CA-MRSA. In addition, APACHE III score was significantly higher in COHCA-MRSA than in CA-MRSA. Both the 7-day and 30-day mortality rates in COHCA-MRSA, 14.6% (7/48) and 29.2% (14/48), respectively, were higher than those in CA-MRSA without a significant difference. SCCmec II was more common in COHCA-MRSA, but SCCmecVT was more common in CA-MRSA. The majority of MRSA isolates belonged to ST59, ST239, and ST5. ST59 was significantly more common in CA-MRSA, while ST239 was nearly equally common in both CA-MRSA and COHCA-MRSA. SCCmec III and II isolates were the first and second most resistant to the antibiotics commonly used for S. aureus, whereas SCCmecVT isolates were the most susceptible to these antibiotics. We conclude that, although both CA-MRSA and COHCA-MRSA bacteremia had community onset, these 2 MRSA infections were different in underlying diseases, risk of mortality, SCCmec types, sequence types, and antimicrobial susceptibility. It is more appropriate to understand the MRSA pathogen and clinical features based on etiology and ST types than based on the location of disease onset. CA-MRSA and HCA-MRSA should be differentiated also based on etiology and ST types, in addition to location of acquisition.

Risk factors for scabies in Taiwan.

BACKGROUND: Scabies is a global problem. Transmission of scabies is usually due to direct or indirect contact. Delay in diagnosis may result in the spread of the scabies mite. Prompt diagnosis and treatment are important. METHODS: In this study, we collected data from 52 scabies patients and analyzed the risk factors for scabies with the case-control method. RESULTS: Our study has revealed that the patients who were bedridden [odds ratio (OR) 6.72, p < 0.0001], living in a nursing home (OR 9.89, p < 0.0001), had a higher clinical severity status before admission (OR 1.25, p < 0.0001), and a catheter inserted (including nasogastric tube, Foley catheter, Port-A, or Hickman catheter) (OR 9.05, p < 0.0001) were significantly more likely to acquire scabies infection. CONCLUSION: To prevent scabies, proper management of the nursing home setting, including adequate cleaning of the contaminated clothing, bedding and equipment, in combination with treating all suspected scabies patients, and contact isolation are important and necessary.

In vitro activities of nine current antibiotics against culprit bacteria in nosocomial infections in an institution in Northern Taiwan.

BACKGROUND: In recent years, there has been a rapid worldwide emergence of multidrugresistant (MDR) pathogens, especially in cases of nosocomial infections. This study assesses the in vitro activities of ampicillin/sulbactam, cefpirome, colistin, daptomycin, ertapenem, meropenem, teicoplanin, tigecycline and vancomycin against 208 aerobic bacterial pathogens that caused 197 nosocomial infections in 184 patients. METHODS: Antimicrobial susceptibility was evaluated by Etest. Broth dilution method was utilized in tigecycline susceptibility testing. RESULTS: Most (140/208, 67%) of the isolates were facultative Gram-negative bacilli. Of the 31 oxacillin-resistant S. aureus (ORSA) isolates, 16 were susceptible to daptomycin (16/31, 51.6%) according to the breakpoint ≤ 1 µg/ml. All 31 ORSA isolates were susceptible to teicoplanin, and vancomycin but MICs of vancomycin for all 31 ORSA isolates were ≥ 1 µg/ml. Of the 21 isolates of A. baumannii that were multiple-drug-resistant, 19 isolates (19/21, 90%) were susceptible to colistin and 18 isolates (18/21, 86%) sensitive to tigecycline. Of the 22 isolates of E. coli with extended-spectrum beta-lactamase (ESBL), the most susceptible antimicrobial agent were colistin (20/22, 91%), ertapenem (21/22, 96%), meropenem and tigecycline (22/22, 100%). Of the 11 isolates of P. aeruginosa, 6 isolates were susceptible to colistin (6/11, 55%) and all isolates were susceptible to meropenem (11/11, 100%). CONCLUSION: For nosocomial infections caused by MDR-Acinetobacter baumannii, colistin and tigecycline are usually susceptible according to the result of this study. For nosocomial infections caused by ORSA, ORSA has reduced susceptibility to vancomycin, teicoplanin and daptomycin. For MDR-P. aeruginosa, further study is needed.

Hookworm infection in a healthy adult that manifested as severe eosinphilia and diarrhea.

A 54-year-old male was admitted because of having suffered from progressive watery diarrhea for 12 days. He had no history of diabetes mellitus, hypertension, heart disease, organ transplantation, or malignancy. After admission, he still complained of diarrhea despite medical treatment. The laboratory examination showed leukocytosis with eosinophilia and a stool examination by the concentration method was negative four times. When a sigmoidoscopy was performed as a part of an explorative survey, a single protruding mass consisting if a moving adult hookworm was found. The fifth stool examination by the concentration method identified hookworm ova. The patient was treated with oral mebendazole 100 mg twice a day for 3 days. The diarrhea and eosinophilia subsided after this treatment.

Disk diffusion test and E-test with enriched Mueller-Hinton agar for determining susceptibility of Candida species to voriconazole and fluconazole.

BACKGROUND AND PURPOSE: A simplified antifungal disk diffusion test using Mueller-Hinton agar containing 2% glucose and methylene blue 5 microg/mL (GM-MH, Clinical and Laboratory Standards Institute [CLSI] M44-A) has proved to correlate well with the standard reference test. A new azole, voriconazole, has recently been approved for clinical therapy in Taiwan. This study investigated the reliability of the disk diffusion test with GM-MH agar and compared the results with those of the E-test using GM-MH agar to determine the voriconazole and fluconazole susceptibility of Candida isolates. METHODS: The antimicrobial susceptibility of Candida isolates were evaluated by E-test and disk diffusion test in accordance with the guidelines of the CLSI, and compared with the reference antifungal macrodilution susceptibility test (CLSI M27-A). RESULTS: The antifungal disk diffusion test and the E-test using GM-MH agar plate provided a sufficiently accurate, time-efficient, and cost-effective way to determine the susceptibility of 182 Candida spp. to voriconazole and fluconazole. There was a high correlation between the test results of the E-test using the GM-MH agar plate and those obtained by the reference antifungal macrodilution susceptibility test (CLSI M27-A). The results of the E-test and those of the 1-microg voriconazole disk diffusion test on the GM-MH agar plate at 24 h had a high correlation. All the minimal inhibitory concentrations of voriconazole for all Candida spp. were <8 microg/mL. The positive predictive value of the susceptible disk test of voriconazole on the GM-MH agar plate was 100% at 24 h for C. albicans and other Candida spp. CONCLUSION: The disk diffusion test and the E-test using the GM-MH agar plate can be performed quickly, simply, and cost-effectively, and are practicable methods for the initial testing of the susceptibility of Candida spp. to voriconazole and fluconazole.

Host factors do not influence the colonization or infection by fluconazole resistant Candida species in hospitalized patients.

Nosocomial yeast infections have significantly increased during the past two decades in industrialized countries, including Taiwan. This has been associated with the emergence of resistance to fluconazole and other antifungal drugs. The medical records of 88 patients, colonized or infected with Candida species, from nine of the 22 hospitals that provided clinical isolates to the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) program in 1999 were reviewed. A total of 35 patients contributed fluconazole resistant strains [minimum inhibitory concentrations (MICs) > or = 64 mg/l], while the remaining 53 patients contributed susceptible ones (MICs < or = 8 mg/l). Fluconazole resistance was more frequent among isolates of Candida tropicalis (46.5%) than either C. albicans (36.8%) or C. glabrata (30.8%). There was no significant difference in demographic characteristics or underlying diseases among patients contributing strains different in drug susceptibility.

Comparative antimicrobial susceptibility of aerobic and facultative bacteria from community-acquired bacteremia to ertapenem in Taiwan.

BACKGROUND: Ertapenem is a once-a-day carbapenem and has excellent activity against many gram-positive and gram-negative aerobic, facultative, and anaerobic bacteria. The susceptibility of isolates of community-acquired bacteremia to ertapenem has not been reported yet. The present study assesses the in vitro activity of ertapenem against aerobic and facultative bacterial pathogens isolated from patients with community-acquired bacteremia by determining and comparing the MICs of cefepime, cefoxitin, ceftazidime, ceftriaxone, ertapenem, piperacillin, piperacillin-tazobactam, ciprofloxacin, amikacin and gentamicin. The prevalence of extended broad spectrum beta-lactamases (ESBL) producing strains of community-acquired bacteremia and their susceptibility to these antibiotics are investigated. METHODS: Aerobic and facultative bacteria isolated from blood obtained from hospitalized patients with community-acquired bacteremia within 48 hours of admission between August 1, 2004 and September 30, 2004 in Chang Gung Memorial Hospital at Keelung, Taiwan, were identified using standard procedures. Antimicrobial susceptibility was evaluated by Etest according to the standard guidelines provided by the manufacturer and document M100-S16 Performance Standards of the Clinical Laboratory of Standard Institute. Antimicrobial agents including cefepime, cefoxitin, ceftazidime, ceftriaxone, ertapenem, piperacillin, piperacillin-tazobactam, ciprofloxacin, amikacin and gentamicin were used against the bacterial isolates to test their MICs as determined by Etest. For Staphylococcus aureus isolates, MICs of oxacillin were also tested by Etest to differentiate oxacillin-sensitive and oxacillin-resistant S. aureus. RESULTS: Ertapenem was highly active in vitro against many aerobic and facultative bacterial pathogens commonly recovered from patients with community-acquired bacteremia (128/159, 80.5 %). Ertapenem had more potent activity than ceftriaxone, piperacillin-tazobactam, or ciprofloxacin against oxacillin-susceptible S. aureus (17/17, 100%)and was more active than any of these agents against enterobacteriaceae (82/82, 100%). CONCLUSION: Based on the microbiology pattern of community-acquired bacteremia, initial empiric treatment that requires coverage of a broad spectrum of both gram-negative and gram-positive aerobic bacteria, such as ertapenem, may be justified in moderately severe cases of community-acquired bacteremia in non-immunocompromised hosts.

Comparison of in vitro activities of levofloxacin, ciprofloxacin, ceftazidime, cefepime, imipenem, and piperacillin-tazobactam against aerobic bacterial pathogens from patients with nosocomial infections.

BACKGROUND AND PURPOSE: There is a rapid worldwide emergence of multidrug-resistant pathogens, especially in nosocomial isolates. This study compared the in vitro activities of levofloxacin, ciprofloxacin, ceftazidime, cefepime, imipenem, and piperacillin-tazobactam against 208 aerobic bacterial pathogens that caused 197 nosocomial infections in 184 patients. METHODS: Antimicrobial susceptibility was evaluated by E test in accordance with the guidelines of the National Committee for Clinical Laboratory Standards. RESULTS: Most (140/208, 67%) of the isolates were facultative Gram-negative bacilli. Levofloxacin and ciprofloxacin were the most effective (22/22, 100%) against oxacillin-sensitive Staphylococcus aureus. None of the antibiotics tested were found to be effective (0/25) against oxacillin-resistant S. aureus. Of the 11 isolates of Acinetobacter baumannii that were not pandrug-resistant (PDR), only 9 isolates (9/11, 81%) were sensitive to imipenem and 5 isolates (5/11, 45%) were sensitive to levofloxacin, ciprofloxacin, and ceftazidime. Another 22 isolates of A. baumannii that were PDR were completely resistant to all 6 antibiotics. The majority of isolates of Pseudomonas aeruginosa were sensitive to these 6 antimicrobial agents with 10/11 (91%) sensitive to levofloxacin and ciprofloxacin, 9/11 (83%) sensitive to ceftazidime, cefepime and piperacillin-tazobactam, and 8/11 (75%) sensitive to imipenem. CONCLUSIONS: The majority of the bacterial isolates causing nosocomial infections were found to be sensitive to the 6 antibiotics tested. Bacterial isolates of nosocomial infections that were completely resistant to these 6 antibiotics were PDR A. baumannii, PDR P. aeruginosa, and oxacillin-resistant S. aureus. More potent antimicrobial agents are needed to treat infections caused by PDR A. baumannii and PDR P. aeruginosa.

An outbreak of methicillin-resistant Staphylococcus aureus infections related to central venous catheters for hemodialysis.

OBJECTIVES: To determine risk factors for hemodialysis catheter-related bloodstream infections (HCRBSIs) and investigate whether use of maximal sterile barrier precautions would prevent HCRBSIs. SETTING: Tertiary-care medical center hemodialysis unit. DESIGN: Open trial with historical comparison and case-control study of risk factors for HCRBSIs. METHODS: Prospective surveillance was used to compare HCRBSI rates for 1 year before and after implementation of maximal sterile barrier precautions. A case-control study compared 50 case-patients with HCRBSI with 51 randomly selected control-patients. RESULTS: The HCRBSI rate was 1.6% per 100 dialysis runs (CI95, 1.1%-2.3%) in the first year and 0.77% (CI95, 0.5%-1.1%) in the second year (P = .0106). The most frequent cause of HCRBSI was MRSA in the first year (15 of 32) and MSSA in the second year (13 of 18). Ten MRSA blood isolates in the first year were identical by PFGE. Diabetes mellitus was a risk factor for HCRBSI. Age, gender, site of hemodialysis central venous catheter (CVC), other underlying diseases, coma score, APACHE II score, serum albumin level, and cholesterol level were not associated with HCRBSI and did not change between the 2 years. Hospital stay was prolonged for case-patients (32.78 +/- 20.96 days) versus control-patients (22.75 +/- 17.33 days), but mortality did not differ. CONCLUSIONS: Use of maximal sterile barrier precautions during the insertion of CVCs reduced HCRBSIs in dialysis patients and seemed cost-effective. Diabetes mellitus was associated with HCRBSI. An outbreak of MRSA in the first year was likely caused by cross-infection via medical personnel.

Efficacy and tolerability of linezolid in treating severe skin and soft tissue infections caused by Gram-positive pathogens.

BACKGROUND AND PURPOSE: Linezolid, an oxazolidinone, has shown efficacy in the treatment of adults with nosocomial or community-acquired pneumonia; skin and soft tissue infections; and infections due to methicillin-resistant Staphylococcus aureus. The purpose of this open-label, single-arm, multicenter study was to evaluate the efficacy and tolerability of linezolid in patients from the Asia-Pacific Region with severe Gram-positive skin and soft tissue infections. METHODS: 166 patients at 27 sites in 7 countries from the Asia-Pacific region were enrolled. The patients had severe skin infection involving the deeper layers or extensive surface area. Patients received 7 to 28 days of treatment with linezolid by clinical judgment. All patients received intravenous linezolid 600 mg twice a day initially and were switched over to an equivalent oral dose (600 mg twice a day) when the investigator discerned clinical improvement. The primary efficacy endpoint in this study was clinical outcome at the follow-up visit, 14 to 21 days after completion of treatment (test of cure), and the secondary efficacy variable was microbiologic response at test-of-cure. RESULTS: 166 patients received the study medication and were included in the intent-to-treat analysis. The clinical success rate was approximately 93% in both the intent-to-treat and clinically evaluable populations at the end of treatment and test-of-cure visits. In the modified intent-to-treat and microbiologically evaluable populations, the microbiologic success rates at the test-of-cure visit were 88.9% and 93.8%, respectively. The most frequent treatment-emergent adverse events were nausea (13%), dizziness (8%), anemia (7%), and vomiting (5%). CONCLUSIONS: Linezolid was effective and well tolerated in patients with severe skin and soft tissue infections caused by Gram-positive pathogens.

Detection of Enterobius vermicularis eggs in the submucosa of the transverse colon of a man presenting with colon carcinoma.

We report a case of a chronic infiltrate of the intestinal wall of the transverse colon by the eggs of Enterobius vermicularis in a man who had immigrated to Taiwan from mainland China 50 years ago. During surgery for suspected transverse colon carcinoma, histologic examination of the tumor mass revealed eggs of E. vermicularis embedded in granulation tissue in the submucosa of the transverse colon. Results of a stool examination were negative for eggs but strongly positive for occult blood. The mass in the transverse colon was completely removed during surgery. At the present time, the patient remains asymptomatic.

Candida peritonitis due to peptic ulcer perforation: incidence rate, risk factors, prognosis and susceptibility to fluconazole and amphotericin B.

Sixty-two cases of peritonitis due to peptic ulcer perforation were diagnosed between January 2000 and December 2000. Of these 62 cases, 23 isolates of Candida in 23 cases (CP) were cultured from peritoneal fluid. Cultures of peritoneal fluid of 10 (BP) of the remaining 39 cases was positive for bacteria only. Cultures of peritoneal fluid of the remaining 29 cases was negative. Comparison of CP, BP and culture-negative cases did not reveal any significant risk factor. Of the 23 Candida isolates, the Candida species and 48-h MICs of fluconazole and amphotericin B (mean, range ug/ml) were C. albicans 18 (0.688, 0.125-1.0; 0.297, 0.031-0.5), C. glabrata 3 (0.542, 0.125-1.0; 0.25, 0.125-0.5), C. tropicalis 1 (0.25; 0.5), C. intermedia 1 (1.0; 0.125) respectively. Mortality rates of CP, BP and culture-negative peritonitis due to infection were 5/23(21.7%), 0/10 and 1/29(3.4%) respectively. Without effective antifungal therapy, the mortality rate of CP was not low.