Chang-Pan Liu

Aerosolized colistin for the treatment of multidrug-resistant Acinetobacter baumannii pneumonia: experience in a tertiary care hospital in Northern Taiwan.

BACKGROUND/PURPOSE Ventilator-associated pneumonia (VAP) due to multidrug-resistant (MDR) Acinetobacter baumannii in critically ill patients presents an emerging challenge to clinicians. Administration of aerosolized colistin as an adjunctive therapy is one therapeutic option mentioned in limited evidence-based studies. This study aimed to evaluate the effectiveness of adjunctive aerosolized colistin treatment for VAP due to MDR pathogens. METHODS We retrospectively reviewed the medical records of patients who had received aerosolized colistin for treatment of VAP due to MDR A. baumannii in our hospital from August to December 2008. RESULTS Forty-five patients were enrolled in our study. The mean age was 71 +/- 15 years. The mean Acute Physiological and Chronic Health Evaluation II (APACHE II) scores on the day of intensive care unit admission and on the first day of aerosolized colistin administration were 22.5 +/- 6.7 and 18.9 +/- 5.7, respectively. The mean duration of intensive care unit stay was 34 +/- 16 days. The mean daily dosage of aerosolized colistin was 4.29 +/- 0.82 million IU, and the mean duration of administration was 10.29 days. Seventeen patients (37.8%) had a favorable microbiological outcome and 26 (57.8%) showed a clinical response. Mortality due to all causes was 42.2%. No adverse effects related to inhaled colistin were recorded. CONCLUSION Aerosolized colistin may be considered as an adjunct to intravenous treatments in patients with VAP due to colistin-susceptible MDR A. baumannii in critically ill patients.

Ceftriaxone Resistance of Nontyphoidal Salmonella enterica Isolates in Northern Taiwan Attributable to Production of CTX-M-14 and CMY-2 β-Lactamases

ABSTRACT Among 3,027 nontyphoidal Salmonella enterica isolates identified between January 1999 and December 2002 in a medical center in northern Taiwan, 31 were resistant to the extended-spectrum cephalosporin ceftriaxone (1.02% [31/3,027]), including 2 in 1999 (0.36% [2/549]), 13 in 2000 (1.49% [13/870]), 7 in 2001 (0.78% [7/893]), and 9 in 2002 (1.26% [9/715]). Sixteen of these isolates belonged to Salmonella serogroup B, nine belonged to serogroup C, four belonged to serogroup D, and two belonged to serogroup E. The majority were from stool cultures. The mechanism of resistance was investigated for eight isolates, including three S. enterica serovar Typhimurium, one S. enterica serovar Wagenia, one S. enterica serovar Senftenberg, one S. enterica serovar Derby, one S. enterica serovar Panama, and one S. enterica serovar Duesseldorf isolate. All eight patients from whom these isolates were recovered had community-acquired infections. All eight isolates were resistant to ampicillin, ceftriaxone, and cefotaxime but susceptible to imipenem and ciprofloxacin. Ceftriaxone resistance was due to the production of the CMY-2 AmpC β-lactamase by seven isolates and the CTX-M-14 β-lactamase by the remaining isolate. Both β-lactamase genes were carried on conjugative plasmids. In a 2.5-kb region encompassing the blaCMY-2 gene, at nucleotide 49 upstream of the start codon of blaCMY-2, three of the seven blaCMY-2-positive isolates had an A nucleotide and four had a G nucleotide. In conclusion, the ceftriaxone resistance of nontyphoidal Salmonella isolates in our hospital was attributed to the CTX-M-14 and CMY-2 β-lactamases.

Fusidic acid for the treatment of bone and joint infections caused by meticillin-resistant Staphylococcus aureus

There is a lack of surveillance data on resistance to fusidic acid (FA) in Asia, and no reviews of FA usage for the treatment of orthopaedic infections have been conducted since the year 2000. In this study, we present a systemic literature review of FA resistance in Asia and the clinical use of FA for the treatment of bone and joint infections (BJIs). The in vitro activity of FA against meticillin-resistant Staphylococcus aureus (MRSA) isolates remains good, with low (<10%) resistance rates in most Asian countries. FA in Asia appears to be a better oral anti-MRSA agent than trimethoprim/sulfamethoxazole and clindamycin. More than 80 cases of FA use for BJI have been reported since 2000 and the recurrence or failure rate is <10%. There is much evidence supporting the use of FA in combination with other antibiotics (e.g. rifampicin) as an oral treatment following intravenous glycopeptide treatment for BJIs.

Clinical characteristics of children and adults hospitalized for influenza virus infection

BACKGROUND/PURPOSE Influenza infection has different clinical presentations and outcomes in children and adults, and bacterial coinfection is associated with significantly higher morbidity and mortality. This study compared the clinical features in children and adults hospitalized for influenza virus infection and the role of concomitant bacteremia. METHODS A retrospective observational cohort study was conducted by a review of medical records of all consecutive patients admitted for influenza infection between April 1, 2009 and February 28, 2011. RESULTS Of the 1203 patients, 76.2% were children, and ranged in age from 1 month to 99 years, with a mortality of 3.1% for adults; no children died. Pneumonia, acute respiratory distress syndrome, acute respiratory failure, septic shock, and cardiovascular complications were more common in adults. Bacteremia was more common in adults than in children (3.5% vs. 0.4%). C-reactive protein (CRP) > 4 mg/dL and a longer hospital stay occurred more often in children with bacteremia than in the group without bacteremia. In adults with bacteremia, acute respiratory failure, septic shock, and cardiovascular complications were more common, with a mortality of 50% versus 1.4% compared with those without bacteremia, and thrombocytopenia and increased CRP were independent risk factors. Using receiver operating characteristic analysis, CRP ≥ 14 mg/dL had a sensitivity of 90.0% and a specificity of 80.0%. CONCLUSION Influenza infection in adults is associated with increased risk of complications, bacteremia, and mortality compared with that in children. Bacteremia in adults with influenza is associated with increased complications and mortality; thrombocytopenia and elevated CRP levels could identify those at risk.

Presence of β-Lactamase Gene TEM-1 DNA Sequence in Commercial Taq DNA Polymerase

The development and spread of expanded-spectrum β-lactamases (ESBLs) that cause resistance to β-lactam antibiotics has contributed to great concern worldwide. Most ESBLs are derived from TEM and SHV β-lactamases by point mutations within the blaTEM and blaSHV genes, giving rise to extended-spectrum drug resistance (2, 3). The standard method for determining the specific ESBL gene for the more than 90 TEM-type and the more than 25 SHV-type ESBLs is PCR followed by nucleotide sequencing (2). We routinely applied the standard method to confirm that ESBL genes were present in clinical strains of Enterobacteriaceae (6). To avoid cross-contamination, we used separate rooms for sample preparation, PCR assembly, and agarose gel analysis. Recently, we noticed that the negative (water) controls used in PCR amplification for blaTEM genes produced positive results; this did not occur when the blaSHV gene was targeted. The PCR product was of the predicted size, and nucleotide sequencing revealed that it was the blaTEM-1 gene. After systematic analysis of pipette tips, microcentrifuge tubes, and reagents for PCR, we found that the Taq DNA polymerase was the source of contamination. As shown in Fig. ​Fig.1,1, Taq DNA polymerase from manufacturer A produced a strong signal, but that from manufacturer B did not. FIG. 1. PCR products amplified from negative (water) controls with primers targeting the blaTEM gene. The product was run on a 1% agarose gel with 0.5× Tris-acetate-EDTA buffer. All reactions were performed in duplicate. Lane M, DNA size marker; lanes ... PCR is widely used to detect specific DNA sequences for purposes of microbial identification, clinical diagnosis, and basic research. Because the method is extremely sensitive, a small amount of contaminating DNA can be a serious problem. Taq DNA polymerase is often expressed as a recombinant protein in Escherichia coli. For studies involving gene cloning and protein expression in E. coli, the blaTEM-1 gene has been the most commonly used selective marker for expression vectors that are generally present in multiple copies (9). It is likely that during Taq DNA polymerase purification, the DNA containing the blaTEM-1 gene was not completely removed. This failure may not be a rare occurrence, but the contamination would be detected only if primers specific for blaTEM gene were used. Several reports have documented the presence of exogenous DNA in commercial Taq DNA polymerases (1, 4, 5, 7, 8, 10). Sources of the contaminating DNA have ranged from bacteria (1, 4) and phage-like DNA (7) to both prokaryotes and eukaryotes (10); in other studies, it was determined that the contaminating DNA was not from E. coli or Thermus aquaticus (5, 8). In all of these previous reports, PCR amplification was performed with universal primers for the highly-conserved 16S rRNA gene, whereas in the present study, amplification was done with primers targeting the blaTEM gene. Nevertheless, investigators, especially those who work on TEM-type ESBLs, should be aware of the possibility that Taq DNA polymerase is contaminated with the blaTEM-1 gene.

Clinical and microbiological analysis of adult perianal abscess

BACKGROUND In Taiwan, Klebsiella pneumoniae is the predominant pathogen causing pyogenic liver abscess in patients with diabetes mellitus (DM). The purpose of our hospital-based study was to determine the predominant bacterial species causing perianal abscess in hospitalized patients with and without DM in Taiwan. METHODS Data on patients admitted and then operated on for perianal abscess during the period of March 2001 to December 2008 were reviewed. Information extracted from medical records included clinical information and laboratory data as well as culture and antibiotic sensitivity results. RESULTS A total of 183 patients underwent surgery for perianal abscess. The most common pathogen causing perianal abscess in non-DM patients was Escherichia coli (67.1%), and the most common pathogen isolated in DM patients was K pneumoniae (60%; p=0.009). Among the 25 patients with DM, incident DM was diagnosed in 24.0% (6 of 25). In addition, five patients had transient hyperglycemia. CONCLUSIONS Escherichia coli was the predominant pathogen isolated from perianal abscesses in patients without DM. Klebsiella pneumoniae, however, was the predominant pathogen isolated in DM patients. In both DM and non-DM patients, more than 90% of K pneumoniae isolates showed in vitro sensitivity to first-generation cephalosporins.

Antimicrobial susceptibility and clinical outcomes of Candida parapsilosis bloodstream infections in a tertiary teaching hospital in Northern Taiwan

BACKGROUND Candida parapsilosis is an emerging non-albicans Candida that is associated with central line-associated infection. C. parapsilosis has higher minimal inhibitory concentration to echinocandin than Candida albicans, and the effects of echinocandin on C. parapsilosis are ambiguous. Therefore, in this study, we aimed to investigate the susceptibility and the correlation between incidence and drug consumption. METHODS This retrospective study was conducted in a tertiary teaching hospital in northern Taiwan between 2008 and 2012. The Candida species distribution, the correlation between the use of antifungal agents and the incidence of C. parapsilosis bloodstream infection, demographic information, clinical characteristics, mortality rate, and in vitro susceptibility of C. parapsilosis were analyzed. RESULTS A total of 77 episodes from 77 patients were included for analysis. The overall 90-day mortality rate was 41.6%. The incidence of C. parapsilosis bloodstream infection showed a moderate positive correlation with the increased defined daily dose of echinocandin. The risk factors associated with mortality included malignancy or a metastatic tumor. Multivariate logistical regression analysis showed that patients with malignancy had higher odds ratios in terms of mortality. The rate of C. parapsilosis resistance to fluconazole was 3%, whereas the susceptibility rate was 95.5%. CONCLUSION Underlying comorbidity and malignancy were factors leading to death in patients with C. parapsilosis bloodstream infection. Catheter removal did not influence the mortality rate. The survival rate of patients receiving echinocandin was lower than the group receiving fluconazole. Fluconazole remains the drug of choice to treat C. parapsilosis bloodstream infections.

Clinical characteristics and treatment outcomes of patients with tubo-ovarian abscess at a tertiary care hospital in Northern Taiwan.

BACKGROUND/PURPOSE Controversy exists regarding the need for surgical intervention in patients with tubo-ovarian abscess (TOA). This study was aimed at investigating the clinical characteristics and treatment outcomes in patients with TOA at a tertiary care hospital in Taiwan. METHODS The medical records of 83 patients who presented at the hospital with TOA between January 1, 2006, and December 31, 2007, were retrospectively reviewed. Outcomes of patients who received medical treatment alone or underwent surgical intervention were analyzed using univariate and logistic regression analyses. RESULTS Among the 83 patients with TOA, 13 patients (15.7%) underwent surgical intervention, and 70 patients (84.3%) received medical treatment alone. Significant variables related to surgical treatment in the univariate analysis were length of stay (short vs. long; t = -2.267, p = 0.026), department of admission (emergency room vs. outpatient department; χ(2) = 7.459, p = 0.006), number of live births (nulliparous vs. multiparous; χ(2) = 18.202, p = 0.001), and C-reactive protein (CRP) level (high vs. low; t = -2.250, p = 0.028). Logistic regression analysis performed to determine influential factors for surgical treatment showed that the operation odds ratio of three to four live births versus no live births was 33.995 (p = 0.043) and that of two live births versus no live births was 13.598 (p = 0.026). CONCLUSION Patients with TOA who underwent surgery had a longer duration of hospitalization. Among the patients who underwent surgical intervention, those admitted to the emergency room had higher CRP levels and were more likely to be multiparous.

Citrobacter freundii bacteremia: Risk factors of mortality and prevalence of resistance genes

BACKGROUND/PURPOSE Multidrug-resistant strains of Citrobacter have emerged, which carry Amp-C β-lactamase (Amp-C), broad-spectrum β-lactamase, extended-spectrum β-lactamase (ESBL), and other resistance mechanisms. These strains are associated with a higher rate of in-hospital mortality. The object of this study is to determine the mortality risk factors, susceptibility pattern to antibiotics, and prevalence of resistance genes in patients with Citrobacter freundii bacteremia. METHODS From January 2009 to December 2014, blood isolates of C. freundii were collected in MacKay Memorial Hospital, Taipei, Taiwan. PCR technique and sequencing were performed for resistance genes. Pulsed-field gel electrophoresis (PFGE) was done using XbaI restriction enzyme. The clinical characteristics and risk factors for mortality are demonstrated. RESULTS The 36 blood isolates of C. freundii belonged to 32 different PFGE pulsotypes, and 15 isolates (41.7%) were polymicrobial. The most common source of infection was intra-abdominal origin (61.1%), followed by unknown sources (22.2%), the urinary tract (8.3%), intravascular catheter (5.6%), and soft tissue (2.8%). High degree of antibiotic resistance was noted for cefazolin (100%), cefoxitin (97.2%), and cefuroxime (66.7%). The blaTEM-1 resistance gene was present in 16.7% isolates. 72.2% isolates carried blaAmpC and 5.6% isolates carried ESBL genes (blaSHV-12 or blaCTX-M-15). Multivariate analysis indicated that the independent risk factor for 28-day mortality was carrying the blaTEM-1 resistance gene. CONCLUSION For patients with C. freundii bacteremia, carrying the blaTEM-1 resistance gene was an independent risk factor for 28-day mortality. Carbapenems, fourth-generation cephalosporins, amikacin, and quinolones are still reliable agents for drug-resistant strains.

Lemierre's syndrome in a patient with habitual toothpick usage

Lemierres syndrome is characterized by septic thrombophlebitis of the internal jugular vein that is complicated by metastatic infections. The disease usually presents after oropharyngeal infection. In rare cases, odontogenic infection has been implicated as culprit. Here, we report a case of Lemierres syndrome that most likely developed secondary to toothpick usage. The patient had an uneventful recovery after the timely administration of the appropriate antibiotics.