Trends in the susceptibility of clinically important resistant bacteria to tigecycline: results from the Tigecycline In Vitro Surveillance in Taiwan study, 2006 to 2010.

The Tigecycline In Vitro Surveillance in Taiwan (TIST) study, a nationwide, prospective surveillance during 2006 to 2010, collected a total of 7,793 clinical isolates, including methicillin-resistant Staphylococcus aureus (MRSA) (n = 1,834), penicillin-resistant Streptococcus pneumoniae (PRSP) (n = 423), vancomycin-resistant enterococci (VRE) (n = 219), extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli (n = 1,141), ESBL-producing Klebsiella pneumoniae (n = 1,330), Acinetobacter baumannii (n = 1,645), and Stenotrophomonas maltophilia (n = 903), from different specimens from 20 different hospitals in Taiwan. MICs of tigecycline were determined following the criteria of the U.S. Food and Drug Administration (FDA) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST-2011). Among drug-resistant Gram-positive pathogens, all of the PRSP isolates were susceptible to tigecycline (MIC(90), 0.03 µg/ml), and only one MRSA isolate (MIC(90), 0.5 µg/ml) and three VRE isolates (MIC(90), 0.125 µg/ml) were nonsusceptible to tigecycline. Among the Gram-negative bacteria, the tigecycline susceptibility rates were 99.65% for ESBL-producing E. coli (MIC(90), 0.5 µg/ml) and 96.32% for ESBL-producing K. pneumoniae (MIC(90), 2 µg/ml) when interpreted by FDA criteria but were 98.7% and 85.8%, respectively, when interpreted by EUCAST-2011 criteria. The susceptibility rate for A. baumannii (MIC(90), 4 µg/ml) decreased from 80.9% in 2006 to 55.3% in 2009 but increased to 73.4% in 2010. A bimodal MIC distribution was found among carbapenem-susceptible A. baumannii isolates, and a unimodal MIC distribution was found among carbapenem-nonsusceptible A. baumannii isolates. In Taiwan, tigecycline continues to have excellent in vitro activity against several major clinically important drug-resistant bacteria, with the exception of A. baumannii.

Trends in susceptibility of vancomycin-resistant Enterococcus faecium to tigecycline, daptomycin, and linezolid and molecular epidemiology of the isolates: results from the Tigecycline In Vitro Surveillance in Taiwan (TIST) study, 2006 to 2010.

Among the 219 vancomycin-resistant Enterococcus faecium isolates collected in 20 Taiwanese hospitals from 2006 to 2010, all were susceptible to linezolid and daptomycin, and 98.6% were susceptible to tigecycline. There was a shift toward higher tigecycline MIC values (MIC(90)s) from 2006-2007 (0.06 µg/ml) to 2008-2010 (0.12 µg/ml). The MIC(90)s of daptomycin and linezolid remained stationary. Although pulsotypes among the isolates from the 20 hospitals varied, intrahospital spreading of several clones was identified in 13 hospitals.

Agreement assessment of tigecycline susceptibilities determined by the disk diffusion and broth microdilution methods among commonly encountered resistant bacterial isolates: results from the Tigecycline In Vitro Surveillance in Taiwan (TIST) study, 2008 to 2010.

The Tigecycline In Vitro Surveillance in Taiwan (TIST) study, initiated in 2006, is a nationwide surveillance program designed to longitudinally monitor the in vitro activity of tigecycline against commonly encountered drug-resistant bacteria. This study compared the in vitro activity of tigecycline against 3,014 isolates of clinically important drug-resistant bacteria using the standard broth microdilution and disk diffusion methods. Species studied included methicillin-resistant Staphylococcus aureus (MRSA; n = 759), vancomycin-resistant Enterococcus faecium (VRE; n = 191), extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli (n = 602), ESBL-producing Klebsiella pneumoniae (n = 736), and Acinetobacter baumannii (n = 726) that had been collected from patients treated between 2008 and 2010 at 20 hospitals in Taiwan. MICs and inhibition zone diameters were interpreted according to the currently recommended U.S. Food and Drug Administration (FDA) criteria and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. The MIC(90) values of tigecycline against MRSA, VRE, ESBL-producing E. coli, ESBL-producing K. pneumoniae, and A. baumannii were 0.5, 0.125, 0.5, 2, and 8 µg/ml, respectively. The total error rates between the two methods using the FDA criteria were high: 38.4% for ESBL-producing K. pneumoniae and 33.8% for A. baumannii. Using the EUCAST criteria, the total error rate was also high (54.6%) for A. baumannii isolates. The total error rates between these two methods were <5% for MRSA, VRE, and ESBL-producing E. coli. For routine susceptibility testing of ESBL-producing K. pneumoniae and A. baumannii against tigecycline, the broth microdilution method should be used because of the poor correlation of results between these two methods.

Characteristics of pncA mutations in multidrug-resistant tuberculosis in Taiwan.

BACKGROUND: Pyrazinamide (PZA) is an important first-line drug in multidrug-resistant tuberculosis (MDRTB) treatment. However, the unreliable results obtained from traditional susceptibility testing limits its usefulness in clinical settings. The detection of pncA gene mutations is a potential surrogate of PZA susceptibility testing, especially in MDRTB isolates. The impact of genotypes of M. tuberculosis in pncA gene mutations also remains to be clarified. METHODS: MDRTB isolates were collected from six hospitals in Taiwan from January 2007 to December 2009. pncA gene sequencing, pyrazinamidase activity testing, and spoligotyping were performed on all of the isolates. PZA susceptibility was determined by the BACTEC MGIT 960 PZA method. The sensitivity and specificity of pncA gene analysis were estimated based on the results of PZA susceptibility testing. RESULTS: A total of 66 MDRTB isolates, including 37 Beijing and 29 non-Beijing strains, were included for analysis. Among these isolates, 36 (54.5%) were PZA-resistant and 30 (45.5%) were PZA-susceptible. The PZA-resistant isolates were more likely to have concomitant resistance to ethambutol and streptomycin. Thirty-seven mutation types out of 30 isolates were identified in the pncA gene, and most of them were point mutations. The sensitivities of pncA gene sequencing for PZA susceptibility in overall isolates, Beijing and non-Beijing strains were 80.6%, 76.2%, and 86.7% respectively, and the specificities were 96.7%, 93.8%, and 100% respectively. CONCLUSIONS: More than half of the MDRTB isolates in this study are PZA-resistant. Analysis of pncA gene mutations helped to identify PZA-susceptible MDRTB isolates, especially in non-Beijing strains.

Clinical and microbiological analysis of Elizabethkingia meningoseptica bacteremia in adult patients in Taiwan.

A limited number of reports have documented bacteremia caused by Elizabethkingia meningoseptica (Chryseobacterium meningosepticum) in adults. Most cases have occurred in Taiwan. This study investigated the clinical features and risk factors for mortality from E. meningoseptica bacteremia and the antimicrobial susceptibilities of the isolates. Patients with E. meningoseptica bacteremia were retrospectively analyzed at a medical center/teaching hospital in northern Taiwan over a 3-y period. We analyzed clinical features and outcomes of patients and antimicrobial susceptibilities and pulsed-field gel electrophoresis (PFGE) results of the isolates. 28 patients had nosocomial bacteremia and 4 patients had healthcare associated bacteremia. The isolates exhibited variable susceptibilities to levofloxacin, ciprofloxacin, piperacillin-tazobactam, tigecycline, and trimethoprim-sulfamethoxazole. PFGE demonstrated that most isolates were epidemiologically unrelated. The 28-d mortality rate was 41%. Multivariate analysis indicated that shock and use of inappropriate antibiotics were independent risk factors for mortality. In conclusion, nosocomial bloodstream infection due to E. meningoseptica is an increasing problem in Taiwan. Our study indicates that patients with E. meningoseptica bacteremia face poor prognoses, with shock and use of inappropriate antibiotics as the main risk factors for mortality. Further clinical study is needed to establish the optimal therapy for E. meningoseptica bacteremia.

Infection of normal C3H/HeN mice with Taenia saginata asiatica oncospheres.

Normal C3H/HeN female mice were used to develop an animal model of Taenia saginata asiatica oncosphere infection. The host cellular immune response in this model was analyzed by a cytokine enzyme-linked immunosorbent assay (cytokine ELISA) and flow cytometry. Tumor-like cysts containing cysticerci were recovered from the inoculation sites of female mice 7 weeks postinfection with the T. saginata asiatica oncospheres. A sharp increase and sustained elevation in the ability of spleen cells to produce interferon-gamma and interleukin (IL)-2 revealed that cellular immunity played an important role during the infection. An immediate increase in the levels of IL-6 at 1 week postinfection indicated the induction of a local acute inflammatory response. However, no significant change in the levels of IL-10 indicated that Th2 cells were not involved in this immune response. The patterns of cell distribution revealed by flow cytometry also supported the same finding. These results suggested that Th1 cells played a major role in the immune response in C3H/HeN mice during the early stages of the oncosphere infection and that the Th2 response was not induced during the stage of cysticercus formation.

Bacterial colonization of epidural catheters used for short-term postoperative analgesia: microbiological examination and risk factor analysis.

BACKGROUND: The authors conducted this prospective study to determine the incidence, potential routes, and risk factors of microbial colonization of epidural catheter used for postoperative pain control. METHODS: Two-hundred five patients with epidural analgesia for postoperative pain were studied. On removal of the catheter, five samples were sent for culture: the infusate, a swab from inside the hub of the epidural catheter connector, a swab from the skin around the catheter insertion site, the subcutaneous segment, and the tip of the catheter. Clinical data related to the catheter insertion, management, and general patient conditions were collected. RESULTS: The positive culture rates for the subcutaneous and tip segments of the catheter were 10.5% and 12.2%, respectively. The most common organism in the culture was coagulase-negative staphylococcus. There was a strong linear relationship between bacterial colonization in the skin around the catheter insertion site and growth from the subcutaneous and tip segments of catheter (P = 0.000). Catheter-related events at ward, blood transfusion, and positive culture from the skin at the insertion site were risk factors for bacterial colonization of epidural catheters. Inflammation at catheter insertion site, catheter indwelling time, and level of catheter insertion were not predicators for epidural catheter colonization. CONCLUSIONS: The authors' results suggest that bacterial migration along the epidural catheter track is the most common route of epidural catheter colonization. Maintaining sterile skin around the catheter insertion site will reduce colonization of the epidural catheter tip.

Clinical characteristics and risk factors for attributable mortality in Enterobacter cloacae bacteremia.

BACKGROUND AND PURPOSE: Enterobacter spp. have emerged as an important cause of nosocomial bacteremia. The purpose of this study was to delineate the clinical, laboratory and microbiologic features that may influence prognosis of Enterobacter cloacae and enable a stratification of those patients at high risk of mortality. METHODS: This retrospective study reviewed 108 episodes of E. cloacae bacteremia occurring over a 2-year period (November 2001 to October 2003) at Taipei Veterans General Hospital. Univariate analysis were performed to demonstrate the relation of possible risk factors to death attributable to E. cloacae bacteremia. RESULTS: Ninety-three episodes (86.1%) were hospital-acquired. The most common portal of entry was the genitourinary tract (17.9%) followed by the gastrointestinal tract (15.1%). Underlying diseases associated with E. cloacae bacteremia were neoplastic diseases (42 episodes, 38.9%), diabetes mellitus (20 episodes, 18.5%) and chronic renal failure (18 episodes, 16.7%). The overall mortality rate was 42.6%, and E. cloacae bacteremia-attributable mortality occurred in 22 patients (20.9%). Factors significantly correlated with death attributable to bacteremia were older age, a higher medium number of underlying diseases, hemoglobin <10 g/dL, serum C-reactive protein >10 mg/dL, hypoalbuminemia, disseminated intravascular coagulation, septic shock, respiratory failure, renal failure (creatinine >2 mg/dL) and delayed clinical response after initiation of antibiotic therapy. CONCLUSIONS: Antibiotic-resistant isolates and appropriate empirical antibiotic use were not independent predictors of mortality in this study. The condition of patients at onset of symptoms and presence of underlying diseases appear to be important predictors mortality from E. cloacae bacteremia.

Rates of susceptibility of carbapenems, ceftobiprole, and colistin against clinically important bacteria collected from intensive care units in 2007: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART).

BACKGROUND: Data on susceptibility to ceftobiprole and colistin, and the complete evolutionary trends of minimum inhibitory concentrations (MICs) of important carbapenem agents among important pathogens collected in intensive care units (ICUs) in Taiwan are lacking. METHODS: We surveyed the MIC distribution patterns of ceftobiprole and colistin and susceptibility profiles of some important pathogens collected from patients hospitalized in intensive care units (ICUs) of major teaching hospitals throughout Taiwan in 2007. We also investigated the rates of nonsusceptibility to powerful carbapenems (imipenem, meropenem) among four important species of Enterobacteriaceae (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Proteus mirabilis) collected during the same period. MIC breakpoints recommended by the Clinical and Laboratory Standards Institute in 2014 were applied. RESULTS: Colistin showed excellent in vitro activity (susceptibility rate, 96%) against Acinetobacter baumannii isolates but moderate (73-77% susceptibility rate) activity against isolates of Pseudomonas aeruginosa and E. cloacae. The ceftobiprole MIC90 value was 4 µg/mL for methicillin-resistant Staphylococcus aureus and 16 µg/mL for P. aeruginosa. The phenotype of methicillin resistance did not markedly increase the MIC value of ceftobiprole among S. aureus isolates. Interestingly, the proportion of isolates that displayed nonsusceptibility to imipenem was significantly higher among P. mirabilis isolates than among isolates of the other three Enterobacteriaceae species, regardless of the production of extended-spectrum ß-lactamase. CONCLUSION: Continuous monitoring of susceptibility profiles of ICU pathogens to important antibiotics is warranted to provide appropriate antimicrobial regimens against infections in the ICU.

Risk factors for fatal candidemia caused by Candida albicans and non-albicans Candida species.

BACKGROUND: Invasive fungal infections, such as candidemia, caused by Candida species have been increasing. Candidemia is not only associated with a high mortality (30% to 40%) but also extends the length of hospital stay and increases the costs of medical care. Sepsis caused by Candida species is clinically indistinguishable from bacterial infections. Although, the clinical presentations of the patients with candidemia caused by Candida albicans and non-albicans Candida species (NAC) are indistinguishable, the susceptibilities to antifungal agents of these species are different. In this study, we attempted to identify the risk factors for candidemia caused by C. albicans and NAC in the hope that this may guide initial empiric therapy. METHODS: A retrospective chart review was conducted during 1996 to 1999 at the Veterans General Hospital-Taipei. RESULTS: There were 130 fatal cases of candidemia, including 68 patients with C. albicans and 62 with NAC. Candidemia was the most likely cause of death in 55 of the 130 patients (42.3 %). There was no significant difference in the distribution of Candida species between those died of candidemia and those died of underlying conditions. Patients who had one of the following conditions were more likely to have C. albicans, age > or = 65 years, immunosuppression accounted to prior use of steroids, leukocytosis, in the intensive care unit (ICU), and intravascular and urinary catheters. Patients who had undergone cancer chemotherapy often appeared less critically ill and were more likely to have NAC. CONCLUSION: Clinical and epidemiological differences in the risk factors between candidemia caused by C. albicans and NAC may provide helpful clues to initiate empiric therapy for patients infected with C. albicans versus NAC.

Predictors of mortality in Acinetobacter baumannii bacteremia.

This study retrospectively investigated 149 episodes of Acinetobacter baumannii bacteremia which occurred during a 41-month period from September 1997 to January 2001. Bacteremia was nosocomial in 139 (93%) of the episodes and community-acquired in 10 (7%). Thirty three deaths (22.1%) were attributed to these episodes of A. baumannii bacteremia. The mean age of survivors was younger than that of patients who died of bacteremia (60.4 +/- 19.9 vs 67.1 +/- 17.4) but this result was not significant on univariate analysis (p=0.084). Previous intensive care unit stay was longer among survivors than among patients who died of bacteremia (9.5 vs 18 days, p=0.048). Factors associated with mortality included immunosuppression (p=0.019), shock (p=0.002), recent surgery (p=0.008), invasive procedures such as central venous catheterization (p=0.002), urinary catheterization (p=0.012), placement of a nasogastric tube (p<0.001), pulmonary catheterization (p=0.015), and mechanical ventilation (p=0.035). The number of underlying conditions (p=0.015) and invasive procedures (p<0.001) were positively correlated with mortality. Mortality was significantly associated with lower platelet count (p=0.001) and lower serum albumin concentration (p=0.005). Patients with catheter-related bacteremia had a high survival rate (96.2%), while survival rate was low in patients with infection originating from the respiratory tract (60.8%). Susceptibility testing by agar dilution test indicated that imipenem was the most effective antibiotic, followed by cefepime and ciprofloxacin. The mortality rate was lower in patients who received 1 or more antibiotics to which the isolates were susceptible, but this difference was not significant (p=0.197). On multivariate analysis, factors that independently correlated with mortality were increased age (p=0.003), immunosuppressive status (p=0.001), recent surgery (p=0.002), acute respiratory failure (p=0.004), acute renal failure (p=0.009) and septic shock (p<0.001). These findings highlight the importance of a treatment strategy based on risk stratification among patients with A. baumannii bacteremia.

Impact of the 1997 revised Centers for Disease Control criteria on case rates of legionellosis in Taiwan: review of 38 cases at a teaching hospital, 1998-2002.

In 1997, the United States Centers for Disease Control and Prevention (CDC) published revised case definitions for legionellosis which eliminated the previously used category of "probable case" based on a single indirect fluorescence antibody (IFA) titer. This study evaluated the influence of revision on the case rates of legionellosis in Taiwan. From 1988 to 2002, 4615 patients with pneumonia were tested for legionellosis in our hospital. The testing methods included IFA assay for serum specimens and direct fluorescence antibody (DFA) assay for sputum specimens. Using the revised criteria, Legionnaires' disease (LD) was diagnosed by DFA in 27 cases and by IFA in 11 cases. The most common underlying conditions were cigarette smoking (44.7%), chronic obstructive pulmonary disease (28.9%) and corticosteroid use (26.3%). The clinical features were nonspecific, including fever (73.7%), dyspnea (63.2%), cough (63.2%) and leukocytosis (63.2%). The overall mortality rate was 18.4%, and the directly LD-attributable mortality rate was 10.5%. Nasogastric tube insertion, endotracheal intubation, congestive heart failure before the onset of LD, inappropriate antimicrobial therapy, respiratory failure and absence of fever during the LD course were significantly associated with LD-attributable mortality. Older age (>70 years) was not associated with higher mortality (p=0.053). Using the revised diagnostic criteria in our series, the positive rate of case identification by IFA was 0.26%, while use of the previous case definitions resulted in a positive rate of 7.6% (including probable and definitive cases). Recognition that the original CDC criteria of IFA titer >1:256 or elevation of IFA titer <4-fold in paired sera could not adequately define an LD etiology has led to a dramatic lowering of case rates among studies after the criteria revision in Taiwan and elsewhere. Assays that are faster, more sensitive and less technician dependent are needed to diagnosis this disease.

Carbapenem susceptibility among Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae isolates obtained from patients in intensive care units in Taiwan in 2005, 2007, and 2009.

To investigate the evolutionary trends in non-susceptibility of carbapenems against the isolates of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae from patients hospitalized in intensive care units (ICUs) of major teaching hospitals throughout Taiwan during 2005-2009, we applied the breakpoints of MICs recommended by Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing in 2013. Escalations in imipenem MIC levels for overall E. coli and E. cloacae isolates and extended-spectrum ß-lactamase (ESBL)-producing K. pneumoniae isolates were noted during this period. The overall MIC levels against imipenem and meropenem for subgroups of ESBL producers of 3 Enterobacteriaceae species were significantly higher than those of respective overall groups in 2007 and 2009. Compared with meropenem, we found that significant evidence of imipenem MIC creep and evidence of extraordinarily high rates of non-susceptibility to ertapenem among isolates of 3 species in 2009 existed. The prominent rises in rates of ertapenem non-susceptibility for ESBL-producing E. coli and K. pneumoniae during 2005-2009 and rate of ESBL positivity for E. cloacae between 4 years were notably found. Based on our findings, ertapenem should be used cautiously in management of the ICU infections caused by these potentially ESBL-producing Enterobacteriaceae isolates in Taiwan.

Relationship between the distribution of cefepime minimum inhibitory concentrations and detection of extended-spectrum ß-lactamase production among clinically important Enterobacteriaceae isolates obtained from patients in intensive care units in Taiwan: results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) in 2007.

BACKGROUND: The data on susceptibility of important cephalosporins against four Enterobacteriaceae members producing potential extended-spectrum ß-lactamase (ESBL) collected from Taiwanese intensive care units are lacking. METHODS: Minimum inhibitory concentrations (MICs) of cefotaxime, ceftazidime, and cefepime were determined using agar dilution method, against Escherichia coli (n = 344), Klebsiella pneumoniae (n = 359), Enterobacter cloacae (n = 103), and Proteus mirabilis (n = 78). Susceptibilities of these isolates to three cephalosporins were assessed according to MIC breakpoints recommended by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) in 2013. The double-disk synergy test using disks containing cefepime (30 µg) with or without clavulanate (10 µg) was applied to confirm production of ESBL for isolates with cephalosporin MIC ≥ 2 µg/mL. RESULTS: A total of 175 isolates were verified as ESBL producers. The rates of cefepime susceptibility among the ESBL-producing isolates, according to CLSI (EUCAST) criteria, were 56.7% (22.4%) for E. coli, 61.3% (12.0%) for K. pneumoniae, 57.9% (31.6%) for E. cloacae, and 71.4% (7.1%) for P. mirabilis. Using different cefepime MIC breakpoints (MICs ≥ 16 µg/mL recommended by CLSI criteria and ≥ 2 µg/mL by EUCAST criteria) to define nonsusceptibility, we found that both criteria were poorer at predicting ESBL producers among K. pneumoniae and E. cloacae than among the other two species. In addition, we also found that the cefepime MIC level of 1.0 µg/mL best distinguished non-ESBL- from ESBL-producing K. pneumoniae and E. cloacae. CONCLUSION: To detect ESBLs, CLSI should revise the cefepime MIC breakpoint against Enterobacteriaceae.

Distribution and antifungal susceptibility of Candida species causing candidemia from 1996 to 1999.

Susceptibilities to amphotericin B and fluconazole of 383 Candida species isolated from blood were determined. Candida albicans was the most common species (55.6%), followed by Candida parapsilosis (17.5%), Candida tropicalis (16.5%), Candida glabrata (5.2%), Candida guilliermondii (2.3%), and others (2.9%). All but three isolates, Candida ciferrii, C. tropicalis, and C. glabrata, one each, were susceptible to amphotericin B. A total of 367 (95.8%) and 15 (4.2%) isolates were susceptible and susceptible-dose dependent to fluconazole, respectively. Only one isolate, a C. glabrata, was resistant to fluconazole. Few patients (13%) having prior fluconazole treatments may explain the low rate of resistance to fluconazole in this study.

Epidemiology of community-acquired Staphylococcus aureus bacteremia.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen which has been isolated with increasing frequency in recent decades. Community-acquired MRSA (CA-MRSA) infections have also become increasingly important in recent years. This study retrospectively analyzed the risk factors, duration of hospitalization, yearly trend and seasonal variation in prevalence, and antibiotic susceptibility of isolates of community-acquired S. aureus (CASA) bacteremia and CA-MRSA bacteremia from patients treated in a teaching hospital in northern Taiwan. A total of 104 clinical isolates of CASA bacteremia were collected between January 1999 and December 2001. Among these, 35 (33.7%) were identified as MRSA. After multivariate analysis, the independent risk factors for developing CA-MRSA bacteremia were diabetes mellitus (p=0.028), chronic obstructive lung disease (p=0.037), and renal insufficiency (p=0.041). Only 6 (17.1%) patients in the MRSA group had no identified risk factors. Most of the isolates of CA-MRSA had a high degree of resistance to most antibiotics, including clindamycin (71.4%), trimethoprim-sulfamethoxazole (65.7%), and chloramphenicol (41.2%). No major trend or seasonal variation in the prevalence was found during the study period. No difference in mortality related to resistance pattern was found. Although CA-MRSA is not the major pathogen in community-acquired bacteremia, it should be included in the differential diagnosis of Gram-positive bacterial bloodstream infection, especially in those patients with risk factors. Early empiric therapy with glycopeptides in these patients may reduce morbidity and mortality.

Clinical features and antimicrobial susceptibility trends in Citrobacter freundii bacteremia.

This retrospective study investigated the clinical characteristics and antimicrobial susceptibilities of 36 cases of Citrobacter freundii bacteremia treated at the Taipei Veterans General Hospital from 1996 through 1999. The results showed that the predominant infection site was the intraabdominal region and the mortality was 22%. The resistance of C. freundii to most third-generation cephalosporins and broad-spectrum penicillins increased in both nosocomial and community-acquired C. freundii bacteremia during the study period, and the strategy of using a combination of antimicrobial agents to treat C. freundii infection was effective. This study also demonstrated the importance of appropriate antimicrobial therapy to the successful outcome of C. freundii bacteremia. The guidelines of the National Nosocomial Infections Surveillance System were followed to determine trends of resistance of C. freundii to various antimicrobial agents. The resistance of C. freundii to antibiotics in 1999 (n = 10), compared with the period from 1996 through 1998 (n = 26), increased 66% for ciprofloxacin, 36% for ticarcillin/clavulanate, 70% for piperacillin/tazobactam, and 62.8% for piperacillin, but remained uniformly susceptible to imipenem/cilastatin and the new fluoroquinolone (levofloxacin). This increase in resistance was attributable to the use of third-generation cephalosporin instead of first-generation cephalosporins. These findings indicate the need for new measures to facilitate the appropriate choice of antimicrobial agents for patients with C. freundii bacteremia.

Clinical significance of Candida species isolated from cerebrospinal fluid.

Candida species have only rarely been isolated from the cerebrospinal fluid. Some of these isolates are true pathogens with a high morbidity and mortality, while others are only colonizers or contaminants. Spontaneous recovery from Candida meningitis has also been reported. The purpose of this study was to identify factors indicative of patients positive for Candida from cerebrospinal fluid who should receive antifungal therapy. A total of 36 patients with a positive cerebrospinal fluid culture for Candida were included in this retrospective analysis. Seventeen of these patients had received antifungal therapy under the impression of Candida meningitis. The differences in the case fatality rate and the duration of hospitalization between the antifungal treatment and untreated groups were statistically significant (p<0.04 and p<0.005, respectively). Statistical analysis showed a significant difference in the percentage of patients with previous ventricular shunt (14/17 vs 8/19, p<0.05), central venous line in situ (9/17 vs 1/19, p<0.005), multiple positive cerebrospinal fluid culture (11/17 vs 1/19, p<0.0005), isolation of Candida at least 20 days after hospitalization in adults (6/7 vs 1/13, p<0.005), and cerebrospinal fluid white blood cell count (median 77 vs 2 /mm3, p<0.005). These results suggest that antifungal agent should be initiated promptly in patients whose cerebrospinal fluid is positive for Candida and who have one or more of the identified risk factors.

Clinical characteristics and prognostic factors of patients with Stenotrophomonas maltophilia bacteremia.

Stenotrophomonas maltophilia is an important nosocomial pathogen with intrinsic multi-drug resistance. This retrospective study reviewed 84 episodes of S. maltophilia bacteremia over a 4-year period from July 1999 to September 2003. Stenotrophomonas maltophilia bacteremia was hospital-acquired in 64 patients (76%), and developed after prolonged hospitalization in 48 (57%). Seventy patients (83%) had a central venous catheter (CVC), 64 (76%) had prior antibiotic therapy, 55 (65%) had underlying malignancy, and 43 (51%) were receiving immunosuppressive therapy. Twenty seven percent of the episodes of bacteremia had polymicrobial isolates. The overall and bacteremia-related mortality rates were 44% and 33%, respectively. Forty six percent of the bacteremia-related mortality occurred within 3 days after onset of symptoms. The most common sources of bacteremia were respiratory tract (33%) and CVC (31%), while the source of the bacteremia was unknown in 26% of episodes. The most effective antibiotics in vitro were trimethoprim-sulfamethoxazole, ciprofloxacin, chloramphenicol, and ceftazidime; however, a trend of increasing drug resistance in these agents was identified over the study period. On univariate analysis, nosocomial bacteremia, long-lasting neutropnenia (>10 days), bacteremia originating from the respiratory tract, shock, low serum albumin level (<3 g/dL), and thrombocytopenia (platelet count <100,000/mm3) were significantly related to mortality (p<0.05). Among these variables, shock and thrombocytopenia were independent factors associated with mortality. In contrast, patients with CVC-related bacteremia had a lower mortality rate (odds ratio, 0.04; p<0.001). Patients treated with appropriate antibiotics had a lower mortality rate, but this difference was not significant (p=0.477). In S. maltophilia bacteremia, careful evaluation of CVC was important for identifying the source of bacteremia and predicting prognosis. The source of bacteremia and condition of patients at presentation were the major factors influencing prognosis.

The effect of H2-receptor antagonist and proton pump inhibitor on microbial proliferation in the stomach.

BACKGROUND/AIMS: Intra-gastric bacterial proliferation is frequent in patients with hypochlohydria. However, status of gastric bacterial infection in patients receiving proton pump inhibitor or H2-receptor antagonist remains controversial. The purpose of this study was to investigate the microbial condition of the stomach in patients who received H2-receptor antagonist or proton pump inhibitor. METHODOLOGY: Between November 2000 and January 2002, 102 patients were enrolled in this study. Of these, 52 did not receive any treatment (group I), 26 received H2-receptor antagonist (group II), and 24 received proton pump inhibitor (group III). Ten mL of gastric juice were aspirated for culture during endoscopic examination. The aerobic and anaerobic bacterial and fungal cultures were performed immediately. A glass pH meter measured the pH of the gastric juice. RESULTS: The intra-gastric pH was 2.91+/-2.06 (mean +/- SD), 4.12+/-2.83, and 5.11+/-2.47 for groups I, II, and III, respectively (p=0.001 between groups I and III, p>0.05 between groups I and II, and groups II and III). The positive bacterial culture rates were 66.7% (16/24) in group III, 46.2% (12/26) in group II, and 28.8% (15/52) in group I (p=0.007 between groups III and I,p>0.05 between groups I and II, and groups II and III). The positive candidal culture rates were 12.5% (3/24) in group III, 11.5% (3/26) in group II, and 17.3% (9/52) in group I (p>0.05). CONCLUSIONS: Patients who received proton pump inhibitor had more acid suppression and intra-gastric bacterial infection than those of the control group. The intra-gastric candidal infection was not related to intra-gastric pH or anti-secretory medication in this study.