Prolonged fecal shedding of CTX-M-15-producing Escherichia coli and recurrent sepsis in a patient after cord blood stem-cell transplantation

An extended-spectrum beta-lactamase (CTX-M-15 type)-producing Escherichia coli persisted in the intestinal tract for >5 months in a pediatric patient after cord blood stem-cell transplantation and caused 2 episodes of sepsis. The bla(CTX-M-15) is carried by a large plasmid of approximately 130 kb in size. The prolonged shedding of the highly resistant E. coli posed a great challenge to infection control and public health.

Development of multiple complications in type 2 diabetes is associated with the increase of multiple markers of chronic inflammation

Patients with type 2 diabetes (T2DM) are known at risk for developing cardiovascular disease (CVD), nephropathy, and cancer. We were interested to find out whether multiple markers associated with chronic inflammation are detectable in patients with T2DM and are increased in patients with T2DM who developed additional clinical complications. A sequence of multiple risk markers for atherogenesis, associated with chronic inflammation, was measured in patients with T2DM before and after the development of clinical complications. We found that multiple clinical complications frequently developed simultaneously in patients with T2DM. At the early stage of T2DM, only low levels and low percent elevations of multiple risk markers were detected. However, both the level and the percent elevation of these markers were found to increase with disease progression and the development of clinical complications. We believe that chronic inflammation not only contributes to the pathogenesis of T2DM but also continues to increase in T2DM patients who are developing additional clinical complications. It appears that these multiple markers are potentially useful not only for monitoring the progression of T2DM but also predicting the risk of developing macro- and microvascular disease, nephropathy, and cancer.

A panel of multiple markers associated with chronic systemic inflammation and the risk of atherogenesis is detectable in asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are both lung diseases involving chronic inflammation of the airway. The injury is reversible in asthma whereas it is mostly irreversible in COPD. Both patients of asthma and COPD are known at risk for cardiovascular disease (CVD) and type 2 diabetes (T2DM), nephropathy, and cancer. We measured multiple risk markers for atherogenesis in 55 patients with asthma and 62 patients with COPD. We wanted to know whether risk markers for atherogenesis corresponding to sequence of events of chronic inflammation were also detectable in the airway inflammatory diseases. Elevation of almost all markers involving inflammation of the endothelial cells in the coronary artery were detectable in asthma and COPD involving the inflammation of the epithelial cell lining of the airway. Both the level and % elevation of all markers were found mostly higher in COPD, the more severe form of the lung disease. We believe that these markers are useful for predicting risk of developing clinical complications such as CVD.

Cosmetic liposuction causes only transient elevation of acute inflammatory response and does not advance to oxidative and nitrosative stress

Cosmetic liposuction is a surgical procedure performed on normal nonobese subjects to remove unwanted fat. We are interested to know whether the impact of acute inflammatory response induced by liposuction differs from that of chronic inflammation and whether acute inflammatory response will also advance further and cause oxidative and nitrosative stress leading to various clinical complications. In our investigation we monitored 15 nonobese women prior to liposuction, and one day and one month after the surgery with multiple markers associated with chronic inflammation and oxidative stress. Our results indicate that liposuction causes only a transient elevation of acute inflammatory markers such as interleukin-6 (IL-6), high sensitive C-reactive protein (hCRP), and serum amyloid A (SAA), and a transient decrease of nitric oxide (NO). Apparently the impact of liposuction for normal subjects did not advance beyond acute inflammatory response; there was little change in the levels of markers corresponding to downstream events of chronic systemic inflammation such as adhesion molecules, urinary microalbumin (uMA), homocysteine (Hcy), uric acid (UA), and markers of oxidative stress, including urinary 8-hydroxydeoxyguanosine (8-OhdG) and 3-nitrotyrosine (3NT). It appears that the acute inflammatory response of cosmetic liposuction does not lead to impaired renal function and oxidative and nitrosative damage, which are frequently associated with chronic inflammation.

Multiple risk markers for atherogenesis associated with chronic inflammation are detectable in patients with renal stones

Patients with renal stones are known to be at risk of clinical complications such as cardiovascular disease (CVD), nephropathy, and cancer. Recently, it has been realized that almost all risk markers for CVD, nephropathy, etc. are all markers associated with the sequence of reactions of chronic inflammation. It has been reported that chronic inflammation is involved not only in the pathogenesis of nephrolithiasis but also contributes to the development of clinical complications in this condition; therefore, we decided to find out whether these multiple markers are detectable in patients with renal stones so that they can be used to predict the risk of clinical complications in these patients. There were 33 patients with nephrolithiasis included in this study. We found that almost all major markers of chronic inflammation were elevated in patients with renal stones, including proinflammatory cytokine, acute inflammation markers, adhesion molecules, urinary microalbumin (uMA), myeloperoxidase (MPO), 8-hydroxydeoxyguanosine (8-OHdG), 3-nitrotyrosine (3NT), and monocyte chemoattractant protein. It appears that it is possible to assess the risk of clinical complications by monitoring these markers in patients with renal stones.

Systematic analysis of stutters to enhance the accuracy of chimerism testing

Post-transplantation chimerism testing is important to monitor the engraftment of donor stem cells and for the diagnosis of relapse. Detecting the presence of donor/recipient-specific short tandem repeats (STRs) is a frequently used method for engraftment study. Unfortunately, the interpretation of the STR-based chimerism tests is often subject to interference by the presence of a stutter peak, which is one 4-base repeat unit smaller than an authentic allele. The aim of this study was to systematically analyze and resolve the effect of stutter peaks on the interpretation of STR-based chimerism tests. The AmpFlSTR Identifiler Amplification kit (Applied Biosystems)was used to amplify 15 STR loci using genomic DNA from 30 randomly selected, healthy donors. We found that the stutter peaks had locus-specific characteristics. The stutter percentage was defined as the percentage of the stutter peak area/main STR peak area. Based on mean values for the 30 DNA samples, the stutter percentage varied from locus to locus and ranged from 3.12% to 10.71% for 15 STR loci. The locus-specific stutter effect can be eliminated through appropriately adjusted equations. The usefulness of these equations in the prediction of relapse was confirmed by the 5% sensitivity test. Hence, this report offers a valuable scheme to enhance the accuracy of chimerism testing.

Unusual increase of vancomycin-resistant Enterococcus faecium but not Enterococcus faecalis at a university hospital in Taiwan

BACKGROUND

Enterococcal infections at the Chang Gung Memorial Hospital, Taiwan, have increased significantly in recent years, accompanied by a significant growth of vancomycin resistance from < 1% to 3.8%. However, the significant increase in vancomycin resistance was only found in Enterococcus faecium (from 0.5% to 17.4%).

METHODS

A total of 172 patients infected with vancomycin-resistant enterococci (85 E. faecium and 87 E. faecalis) during 1998-2004 were retrospectively studied. Clinical and laboratory features were analyzed using Stata for Windows (version 8.2). Genotypes of the isolates were determined by infrequent-restriction-site polymerase chain reaction.

RESULTS

Multivariate analysis revealed that prior use of imipenem (odds ratio [OR], 30.1; 95% confidence interval [CI], 4.2-215.9) or clindamycin (OR, 6.5; 95% CI, 1.5-28.1), positive urine cultures (OR, 6.1; 95% CI, 2.1-17.8) and penicillin resistance (OR, 55.9; 95% CI, 18.5-168.3) were significantly associated with the infections caused by vancomycin-resistant E. faecium. Genotyping analysis demonstrated a predominant genotype in 71 (83.5%) of the E. faecium isolates, while diverse genotypes were found among the E. faecalis isolates. No apparent correlation between genotype and any specific ward was found. Up to the end of 2005, primary efforts to restrict imipenem usage and reinforce infection control measures have reduced by half the infections caused by vancomycin-resistant E. faecium.

CONCLUSION

Multiple factors were associated with the unusual increase of vancomycin-resistant E. faecium infections in this hospital. Continuous monitoring of appropriate antimicrobial usage and stringent compliance to infection control measures are required to control the increase of such infections.

Increasing ceftriaxone resistance and multiple alterations of penicillin-binding proteins among penicillin-resistant Streptococcus pneumoniae isolates in Taiwan

The rate of nonsusceptibility of penicillin-resistant Streptococcus pneumoniae strains to ceftriaxone increased significantly in Taiwan in 2005. Approximately 90% of the ceftriaxone-nonsusceptible isolates were found to be of four major serotypes (serotypes 6B, 14, 19F, and 23F). Seven amino acid alterations in the penicillin-binding protein 2B transpeptidase-encoding region specifically contributed to the resistance.

Establishment of a sandwich ELISA using commercial antibody for plasma or serum 3-nitrotyrosine (3NT). Elevation in inflammatory diseases and complementary between 3NT and myeloperoxidase

BACKGROUND

Amino acid tyrosine residue of a protein can be nitrated to form 3-nitrotyrosine (3NT), which is now being considered as a marker of inflammation, oxidative and nitrosative stress.

METHOD

An in-house ELISA has been established using the same commercial antibody for both binding and detection of 3NT containing proteins.

RESULTS

The sensitivity of the in-house ELISA was 1.8 nmol/l. The imprecision was <10% at all concentrations. The in-house assay correlates well with a commercial kit (r=0.89). In addition to EDTA plasma, we found that both heparinized plasma and serum can also be used to quantify 3NT concentration. Using the in-house ELISA we have detected increased concentrations of 3NT in diseases known to be associated with inflammation and also in subjects with polyps. As marker of oxidative stress and inflammation, both 3NT and myeloperoxidase are complementary to each other in test sensitivity.

CONCLUSION

This ELISA can be used in the clinical laboratories to monitor the inflammatory disease activity and assess early risks that are associated with inflammation, oxidative and nitrosative stress.

CMY-2 beta-lactamase-carrying community-acquired urinary tract Escherichia coli: genetic correlation with Salmonella enterica serotypes Choleraesuis and Typhimurium

Forty-six cephamycin-resistant Escherichia coli isolates from patients diagnosed with community-acquired urinary tract infection were selected in order to study their resistance mechanism. With the exception of one isolate producing CMY-4, all isolates produced a CMY-2 beta-lactamase. Molecular typing showed that the CMY-2-producing isolates were not related. Cephamycin resistance was plasmid encoded and conjugatively transferred. Plasmid digest profiles suggested that the plasmids were different. Thirty-nine of the 45 CMY-2-producing isolates harboured a plasmid containing a specific DNA fragment, ISEcp1-bla(CMY-2)-blc-sugE, which was identical to those previously published in CMY-2-producing Salmonella enterica serotype Choleraesuis (SCB67) and Salmonella enterica serotype Typhimurium (pNF1358) from Taiwan and the USA, respectively. Among the remaining six isolates, insertion of IS1294 and IS1 at different positions was observed in one and five isolates, respectively. The regions surrounding bla(CMY-2) of the six isolates were identical to the other 39 isolates as well as to SCB67 and pNF1358. Since the present identical transmissible bla(CMY-2)-carrying element was observed in food animal sources both in the USA and Taiwan, its possible transmission to humans, as revealed in this study, is of great concern. Awareness of this mobile resistance element is required to prevent introduction into hospitals and to reduce the spread of this emerging resistance within the community.

Dissemination of extended-spectrum beta-lactamase-producing Enterobacteriaceae in intensive care units of a medical center in Taiwan

The prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in a tertiary hospital in Taiwan was assessed over a 16-month period. A total of 125 nonrepetitive ESBL-producing isolates of Enterobacter cloacae, Escherichia coli, and Klebsiella pneumoniae were available for investigation using molecular methods. Four predominant intensive care units (ICUs) were identified, and SHV-12 (59%), CTX-M- 3 (36%), and CTX-M-14 (14%) were the three most frequent ESBLs. SHV-12 was predominant among E. cloacae in the burn unit and K. pneumoniae in the other three chest medicine-related ICUs. CTX-M-3 was predominant among E. coli and K. pneumoniae in three other ICUs. The dissemination of ESBL-producing Enterobacteriaceae in four ICUs of a medical center in Taiwan is a consequence of the clonal dissemination of a few epidemic strains along with the horizontal transmission of resistance genes-carrying plasmids among bacterial organisms.

Development of an ELISA for myeloperoxidase on microplate: Normal reference values and effect of temperature on specimen preparation

BACKGROUND

Myeloperoxidase (MPO), a leukocyte enzyme, is implicated in both the pathogenesis and the progression of atherosclerosis.

METHODS

We developed a sandwich ELISA on microplate using commercial antibodies for the measurement of plasma MPO.

RESULTS

The in-house ELISA has a sensitivity of 15 ng/ml. Both within-day and between-day imprecision were <10%. The in-house assay was well correlated with the commercial kit from Oxis (gamma=0.96). We have established normal reference range for MPO for apparently healthy Chinese. No statistical difference was found between males and females and the various age groups. Because the coating antibodies used by two different kits are different in their affinities for MPO, the analysis by the in-house ELISA that was approximately three times that of the Oxis kit when testing the same specimens. We found that it is necessary to keep the heparinized whole blood on ice before centrifugation in order to prevent further release of MPO from the leukocytes at room temperature. For the same reason, serum is not recommended for MPO measurement. We also found that either pooled human plasma or serum containing MPO can be used as calibrators.

CONCLUSIONS

We believe that this ELISA for MPO is useful to assess risk for inflammation, oxidative stress, nitrosative stress, and for predicting cardiac events.

In vivo selection of OmpK35-deficient mutant after cefuroxime therapy for primary liver abscess caused by Klebsiella pneumoniae

OBJECTIVES

The aim of the study was to characterize the genetic basis of beta-lactam resistance developed in clinical isolates of Klebsiella pneumoniae after exposure to cefuroxime.

METHODS

Clinical features of two episodes of liver abscess caused by K. pneumoniae in a diabetic patient were reported. Four isolates (KP(1)/KP(2) and KP(3)/KP(4)) of K. pneumoniae were recovered from cultures of blood/pus in the first and second episodes, respectively. Laboratory investigation of the K. pneumoniae isolates included genotyping by PFGE, resistance gene analysis by PCR amplification and DNA sequencing, and outer membrane protein analysis by SDS-PAGE.

RESULTS

KP(3) and KP(4) were recovered after a 21 day cefuroxime therapy and demonstrated identical genotypes to that of KP(1) and KP(2). However, compared with KP(1) and KP(2), emerging resistance to piperacillin, cefalotin, cefuroxime and cefoxitin was observed. The other antibiotics tested, except ampicillin, retained the same effectiveness against the four isolates, although increases (4- to 8-fold) in the MICs of cefotaxime, ceftriaxone, ceftazidime, cefepime, flomoxef and aztreonam were observed in KP(3) and KP(4). None of the isolates produced extended-spectrum beta-lactamases or plasmid-mediated AmpC beta-lactamases. Deficiency in the expression of an outer membrane protein (OmpK35) was observed in the cefuroxime-resistant isolates, KP(3) and KP(4).

CONCLUSIONS

The increased resistance to cephalosporins in these clinical isolates of K. pneumoniae after exposure to cefuroxime might be related to the loss of OmpK35.

Establishment of an in-house ELISA and the reference range for serum amyloid A (SAA): complementarity between SAA and C-reactive protein as markers of inflammation

INTRODUCTION

Serum amyloid A (SAA) and C-reactive protein (CRP) are both acute-phase reactants synthesized by the liver upon stimulation by proinflammatory cytokines reflecting both the acute and chronic inflammatory states.

METHODS

We have established a one-step, sandwich ELISA on microplate for SAA using commercial antibodies for coating and detection.

RESULTS

This in-house ELISA has a sensitivity of 0.12 mg/l. Both within-day and between-day CVs were <10%. The in-house assay correlated well with the commercial ELISA kit from Anogen (r=0.95). We also established the reference range for apparently healthy Chinese. Statistically higher SAA values were found in those >50 years old. No difference was found between genders. We found only slightly increased levels of SAA in early stage of type 2 diabetics, but highly increased levels of SAA were detected in patients with acute myocardial infarction, generally associated with intense inflammation. At the early stage of type 2 diabetes associated with low inflammation, SAA was found to be complementary to CRP in test sensitivity.

CONCLUSIONS

Based on our data and reports from the literature we believe that SAA responds differently than CRP in inflammatory diseases such as in type 2 diabetes and acute myocardial infarction, and is complementary to CRP in test sensitivity.

Changing molecular epidemiology of methicillin-resistant Staphylococcus aureus bloodstream isolates from a teaching hospital in Northern Taiwan

A changing molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from a university-affiliated hospital in Taiwan during a 4-year interval was demonstrated. The changing epidemiology is due to the introduction of a new epidemic clone (sequence type 5) and a local community clone (sequence type 59) of MRSA into the hospital.

Long-term changes in trace elements in patients undergoing chronic hemodialysis

Although the connection between aluminum intoxication and dialysis dementia was identified in the 1980s, understanding of trace element imbalances in hemodialysis patients is as yet incomplete. Recent application of newer inductively coupled plasma-mass spectrometry (ICP/MS) techniques has resulted in renewed study of this population. We used ICP/MS to evaluate serum concentrations of Cu, Se, Zn, Mn, and Ni in a relatively large population of hemodialysis patients compared with healthy age-matched controls. Comparisons were also done by duration of hemodialysis treatment to see whether length of treatment correlates with severity of imbalance. Patients had significantly lower concentrations of the three elements Se, Zn, and Mn. Patients had significantly higher concentrations of Ni, and there was a positive correlation between duration and severity of imbalance for this one element. There was no difference in Cu concentrations between patients and controls. Our findings confirm relative Ni excess and deficiencies of Se, Zn, and Mn in hemodialysis patients, documenting the value of ICP/MS in research work on trace element imbalances as well as clinical monitoring of individual patients.

Distribution of a transposon-like element carrying blaCMY-2 among Salmonella and other Enterobacteriaceae

OBJECTIVES

The dissemination of cephamycin resistance in Enterobacteriaceae and its correlation with a transposon-like DNA element consisting of a specific tnpA-bla(CMY-2)-blc-sugE structure were investigated.

METHODS

A total of 140 enterobacterial isolates belonging to 17 species (10 genera) of Enterobacteriaceae phenotypically characterized as putative AmpC-producers were evaluated. The isolates were examined by PCR analysis, DNA-DNA hybridization and nucleotide sequencing.

RESULTS

The bla(CMY-2)-carrying element was detected in 34 isolates from 10 species (9 genera), including all 14 Salmonella and 4 Shigella isolates as well as 7 of the 10 Escherichia coli isolates tested. The remaining 9 isolates were from 112 isolates of the other 14 species tested. The genetic structure of the bla(CMY-2)-carrying element was identical in 29 isolates, while in 3 E. coli and 2 Citrobacter isolates an additional insertion sequence IS1 was found inserted at various nucleotide positions close to the 3' end, either within or downstream, of tnpA. In 12 of the 14 representative isolates examined, the bla(CMY-2)-carrying element was found inserted in the finQ gene of various-sized plasmids with highly conserved 8 bp direct repeats flanking the junction regions. Among the other 106 non-CMY-2-producing isolates, plasmid-mediated ampC genes were found only in one isolate of Enterobacter aerogenes which carried a bla(DHA-1)-like gene.

CONCLUSIONS

bla(CMY-2) is the most prevalent plasmid-mediated ampC gene among Enterobacteriaceae. All the bla(CMY-2) genes identified in the present study were associated with a specific transposon-like element that may be responsible for the spread of bla(CMY-2) among Enterobacteriaceae.

Serum TIMP-1 in gastric cancer patients: a potential prognostic biomarker

Tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) is over-expressed in many human malignancies, including gastric cancer, and is associated with poor outcome. The purpose of this study was to evaluate the clinical and prognostic significance of preoperative serum TIMP-1 levels in gastric cancer patients. One hundred and seventy gastric cancer patients who underwent gastrectomy between 1996 and 2001 were enrolled in this study. The serum concentration of TIMP-1 protein in these patients and in 116 healthy controls was determined using an enzyme-linked immunoassay (ELISA). When a serum TIMP-1 level >95 percentile of healthy controls was set as the upper cut-off value (348.8 ng/ml), abnormally high serum TIMP-1 were observed in 29 (17.1%) of the gastric cancer patients vs 4.3% of healthy controls (p<0.001). The sensitivity and specificity of serum TIMP-1 as a diagnostic tumor marker were 17.1% and 97.7%, respectively. Serum TIMP-1 was positively associated with morphologic appearance (Borrmann type), tumor size, depth of wall invasion, lymph node metastasis, liver metastasis, and peritoneal seeding. It was also positively associated with lymphatic invasion, perineural invasion, and pathological stage. It was not significantly associated with age, gender, tumor location, or histological type. A higher serum TIMP-1 group was significantly associated with lower survival rates than the lower serum TIMP-1 group (cut-off value at the median; 5-yr survival rate: 32.3% vs 55.6%, log-rank p = 0.0011). When the patients were divided into 2 groups using the 95 percentile TIMP-1 level of controls as the cut-off value, 5-yr survival rates were 24.6% and 47.5% respectively for the higher and lower TIMP-1 groups (log rank p = 0.0147). An elevated preoperative level of serum TIMP-1 was significantly associated with progressive disease, advanced stage, and worse survival in gastric cancer patients. Although it is not a good marker for diagnosis, elevated serum TIMP-1 level shows promise as a marker for prognosis in patients with gastric cancer.

Correlations of androgen deficiency with clinical symptoms in Taiwanese males

The purpose of this study was to elucidate correlations between different biochemical measurements of androgen deficiency and clinical symptoms in male residents of Taiwan. An investigation of the serum biochemical markers for androgen deficiency in 650 males, including total testosterone, calculated free testosterone, and bioavailable testosterone, was conducted. Measurements of clinical symptoms were obtained using a questionnaire of the androgen deficiency in the aging male (ADAM) by St Louis University (SLQ). Correlations among the biochemical markers, correlations of the biochemical markers and age, and relationships between the biochemical markers and the SLQ were evaluated. The sensitivity and specificity of the SLQ were determined. Bioavailable and calculated free testosterone correlated better with age than did total testosterone. Eighty percent of the men had a positive SLQ, and 20% had a negative SLQ. The percentage of positive SLQ results increased with age. No statistically significant difference was noted between the biochemical markers of bioavailable and calculated free testosterone levels and the SLQ status except for men aged over 70 years. The SLQ in this study showed an acceptable sensitivity of about 80%, but the specificity was poor (about 20%). In conclusion, bioavailable testosterone and calculated free testosterone were more-closely correlated with age and may be better biochemical markers for androgen deficiency. SLQ might not be a suitable single measurement for androgen deficiency and should be used together with biochemical markers.

Development of a multiplex PCR and SHV melting-curve mutation detection system for detection of some SHV and CTX-M beta-lactamases of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae in Taiwan

Infection by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae has been increasing in Taiwan. Accurate identification of the ESBL genes is necessary for surveillance and for epidemiological studies of the mode of transmission in the hospital setting. We describe herein the development of a novel system, which consists of a multiplex PCR to identify bla(SHV), bla(CTX-M-3)-like, and bla(CTX-M-14)-like genes and a modified SHV melting-curve mutation detection method to rapidly distinguish six prevalent bla(SHV) genes (bla(SHV-1), bla(SHV-2), bla(SHV-2a), bla(SHV-5), bla(SHV-11), and bla(SHV-12)) in Taiwan. Sixty-five clinical isolates, which had been characterized by nucleotide sequencing of the bla(SHV) and bla(CTX-M) genes, were identified by the system. The system was then used to genotype the ESBLs from 199 clinical isolates, including 40 Enterobacter cloacae, 68 Escherichia coli, and 91 Klebsiella pneumoniae, collected between August 2002 and March 2003. SHV-12 (80 isolates) was the most prevalent type of ESBL identified, followed in order of frequency by CTX-M-3 (65 isolates) and CTX-M-14 (36 isolates). Seventeen (9%) of the 199 clinical isolates harbored both SHV- and CTX-M-type ESBLs. In contrast to Enterobacter cloacae, the majority of which produced SHV-type ESBLs, E. coli and K. pneumoniae were more likely to possess CTX-M-type ESBLs. Three rare CTX-M types were identified through sequencing of the bla(CTX-M-3)-like (CTX-M-15) and bla(CTX-M-14)-like (CTX-M-9 and CTX-M-13) genes. The system appears to provide an efficient differentiation of ESBLs among E. coli, K. pneumoniae, and Enterobacter cloacae in Taiwan. Moreover, the design of the system can be easily adapted for similar purposes in areas where different ESBLs are prevalent.

Increasing ceftriaxone resistance in Salmonella isolates from a university hospital in Taiwan

OBJECTIVES

Salmonella infection is a distressing health problem worldwide. This study reports the changing epidemiology of Salmonella infections in Taiwan during 1999-2003, with emphasis on increasing ceftriaxone resistance.

METHODS

Records of Salmonella clinical isolates in Chang Gung Memorial Hospital during 1999-2003 were reviewed. All isolates were identified and antimicrobial susceptibility determined by standard methods. A total of 22 ceftriaxone-resistant isolates were investigated by PCR sequencing of the bla(TEM), bla(SHV), bla(CTX-M) and ampC genes. Southern-blot hybridization was used to localize the ampC gene. Infrequent-restriction-site PCR was used to genotype these isolates.

RESULTS

A total of 3635 Salmonella isolates, including 3592 (98.8%) non-typhoid Salmonella, were identified. Serogroup B (55.6%) remained the most predominant, but the prevalence has been decreasing. In contrast, serogroup D infections have increased significantly from 13.6 to 22.8%. Overall resistance to ampicillin and chloramphenicol remained high, with the highest rate (91% to both drugs) observed in Salmonella enterica serotype Choleraesuis in 2003. A sudden upsurge of ciprofloxacin resistance from zero to 69% was found in S. Choleraesuis. Ceftriaxone resistance increased in several serogroups (0.8-2.1%; average, 1.5%). The resistance was associated with plasmid-mediated bla(CMY-2) in 14 cases and extended-spectrum beta-lactamases (ESBLs), including CTX-M-3 (n=6), SHV-2a (n=1) and SHV-12 (n=1), in others. Diverse serotypes and genotypes were found among the ceftriaxone-resistant isolates.

CONCLUSIONS

Increasing ceftriaxone resistance in non-typhoid Salmonella appears to link to the spread of plasmid-mediated ampC or ESBL genes. Effective measures should be taken to prevent the problem worsening.

Recurrent Klebsiella pneumoniae mycotic aneurysm in a diabetic patient and emergence of an extended-spectrum beta-lactamase (CTX-M-24)-containing Klebsiella pneumoniae strain after prolonged treatment with first-generation cephalosporins for mycotic aneurysm

A 68-year-old diabetic woman suffered from mycotic aneurysm due to Klebsiella pneumoniae over her abdominal aorta; she received surgical intervention, followed by treatment with first-generation cephalosporins for 6 months. She was hospitalized again 11 months later because of another episode of mycotic aneurysm caused by K. pneumoniae on her thoracic aorta. Fingerprinting generated by pulsed-field gel electrophoresis and infrequent-restriction-site polymerase indicated K. pneumoniae isolates of the identical clonal strain were responsible for these two mycotic-aneurysm episodes. Unfortunately, nosocomial pneumonia developed at the second hospitalization; blood and purposefully sampled feces specimen cultures both grew CTX-M-24-producing K. pneumoniae, which were of the same strain and genetically nonrelated to the K. pneumoniae strain causing mycotic aneurysms earlier. This is the first report on infection due to CTX-M-24-producing K. pneumoniae. It is unclear whether the prolonged use of first-generation cephalosporins in this case selected a strain of enteric organism possessing the ESBL in question, which was capable of passing this ESBL plasmid to the K. pneumoniae strain causing the nosocomial infection. This report suggests that further observation is needed before one can draw a conclusion on the possibility of the selection of ESBL enteric organism by extensive exposure to first-generation cephalosporins.

Variable resistance patterns of integron-associated multidrug-resistant Acinetobacter baumannii isolates in a surgical intensive care unit

Between 1998 and 2000, we characterized 91 nosocomial isolates of Acinetobacter baumannii by antibiotyping and genotyping. A total of 25 ribotypes were obtained among these 91 isolates. When the isolates from surgical intensive care units (ICUs) and other wards were compared, multiresistant A. baumannii isolates with the same ribotype 25 (R-25) were significantly more prevalent in nosocomial infections among the surgical patients. Further subtyping of the strains by pulsed-field gel electrophoresis confirmed that strains of the same ribotype in surgical ICUs and a few isolates from other wards were identical or clonally related. Different antibiotic resistance profiles were observed among these R-25 isolates. All R-25 isolates contained intI1 integrase, and two clusters of integron cassettes were found. These clusters of cassettes were encoded by an open reading frame (ORF) of -5'CS-aac(3)Ia-aadA1a-unknown or f-3'CS or 5'CS-aacA4-aadA1-catB8-3'CS, indicating the involvement of different resistant genes. Two isolates contained bla (IMP-1), which was acquired from a conjugatively transferable plasmid and did not involve integron-associated resistance. In conclusion, an epidemic of nosocomial infections associated with A. baumannii strains that have different resistance profiles was identified. Resistance profiles can change by a combination of plasmid- and integron-associated acquisition, especially in a unit with high antibiotic selective pressures. Infectious control personnel should be alert to the change in resistance profiles during routine monitoring.

Microplate ELISAs for soluble VCAM-1 and ICAM-1

Soluble vascular cell adhesion molecule (sVCAM-1) and soluble intercellular adhesion molecule (sICAM-1) are adhesion molecules that are detectable in the serum of patients with cancer, cardiovascular diseases (CVD), and type 2 diabetes. This report describes enzyme-linked immunosorbent assays (ELISAs) on microplates for sVCAM-1 and sICAM-1. The ELISAs have the sandwich test format; polyclonal antibodies are coated on microwells and a one-step procedure is used in which the serum specimen and detecting antibody are added simultaneously to an antibody-coated well. These assays both use HRP-conjugated sheep anti-mouse-IgG to generate the color for quantification. Sensitivities for detecting sVCAM-1 and sICAM-1 are 49 and 40 ng/ml, respectively. Coefficients of variation for within-day and day-to-day replicate analyses are <10%. Results by these in-house ELISAs for serum sVCAM-1 and sICAM-1 compared well with those obtained with commercial kits from R&D Systems, Inc. (correlation coefficients = 0.98 and 0.99 for sVCAM-1 and sICAM-1, respectively). Reference values for serum sVCAM-1 and sICAM-1 levels were measured in 369 apparently healthy Chinese adults, age 30 to 79 yr. There was no significant effect of gender on the reference values for sVCAM-1 or sICAM-1. Serum sVCAM-1 levels (mean +/- SD) were higher in subjects 60 yr old (625 +/- 126 ng/ml), compared to those <60 yr old (525 +/- 110 ng/ml) (p <0.001). Age did not significantly affect the reference values for serum sICAM-1 levels (mean +/- SD, 249 +/- 86 ng/ml). The authors believe that these simple, inexpensive ELISAs will be useful for assessing the risks for development of cancer, CVD, and type 2 diabetes.

Microplate ELISA for urine microalbumin: reference values and results in patients with type 2 diabetes and cardiovascular disease

An ELISA for urine microalbumin using microtiter plates has been developed. The assay uses polyclonal anti-human albumin antibody for coating the microtiter plates and the same antibody conjugated with horseradish peroxidase for detection. The assay sensitivity is 1.6 microg/ml. Results by this in-house ELISA show good correlation (r = 0.99) with those obtained by a commercial assay using the Behring BNII autoanalyzer. Within-day and between-day CVs are 10%. Reference values for microalbumin in 769 urine specimens from healthy Chinese subjects were higher in women than men and higher in subjects 50 yr than in those <50 yr of age. Elevated mean concentrations of urine microalbumin were observed in patients with type 2 diabetes and CVD. This in-house ELISA is simple, sensitive, precise, and especially suited for laboratories without expensive autoanalyzers.

Enzymatic assay of homocysteine on microtiter plates or a TECAN analyzer using crude lysate containing recombinant methionine gamma-lyase

An enzymatic assay for plasma homocysteine was developed that uses a crude lysate of E. coli containing the recombinant enzyme, methionine gamma-lyase. The assay uses a commercially available fluorophore and 96-well microtiter plates; it can be performed manually or with the TECAN automated analyzer. The CVs for within-run and between-run precision are < 10%. Close correlation (r > 0.9) was obtained between results by this enzymatic method vs a reference HPLC procedure. In a Chinese population, the concentration of plasma total homocysteine was found to be gender- and age-dependent. Mean concentrations of plasma total homocysteine increased with age and were higher in men than women. Serum homocysteine concentrations did not differ significantly from those in plasma, provided the whole blood specimens were kept at 4 degrees C for 2 hr, or at room temperature for < 45 min, between venepuncture and centrifugation.

Fluoroquinolone resistance in Salmonella enterica serotype Choleraesuis, Taiwan, 2000-2003

Salmonella enterica serotype Choleraesuis is a highly invasive pathogen that infects humans and causes systemic infections that require antimicrobial therapy. Surveillance in Taiwan showed that fluoroquinolone resistance in S. Choleraesuis markedly increased from 2000 to 2003, reaching approximately 70% in 2003.

Bordetella pertussis infection in northern Taiwan, 1997-2001

The clinical presentations of laboratory-confirmed Bordetella pertussis infection in Chang Gung Children's Hospital during 1997 and 2001 were analyzed. Of the 46 cases, 25 (54.3%) were male. The patients ages ranged from 24 days to 37 years, with a mean and median of 4.3 years and 10.5 years, respectively. Forty four patients had vaccination records, among them 23 patients (52.2%) had received > or = 3 doses of pertussis vaccine. Of the patients who were partially vaccinated (received 1 or 2 doses vaccine) or unvaccinated, 16 (69.6%) presented with whooping cough, 5 (22.2%) with post-tussive vomiting, and 13 (59.1%) with cyanosis. Leukocytosis (white blood cells > or = 15,000 cells/microL) and lymphocytosis (lymphocytes > or = 10,000 cells/microL) were observed in 17 (47.2%) and 16 (44.4%) of the patients, respectively. Fourteen patients (30.4%) developed complications, among which pneumonia was the most common (92.3%). Among infants < or = 1 year of age, 95.2% were partially vaccinated (20/21), compared with 5% (1/20) of the patients > 1 year of age (p<0.05). The overall complication rate was 37.5%, compared with 18.2% for patients > 1 year of age (p<0.05). One 2-month-old patient required ventilatory support after the development of cardiopulmonary failure. There was no mortality in this study. In summary, pertussis most commonly occurred in infants who were unvaccinated or partially vaccinated. These patients usually presented with atypical symptoms such as cyanosis or apnea. The importance of vaccination still cannot be overemphasized because immunized patients usually present with milder disease than those who are not immunized.

Comparison of multiplex polymerase chain reaction, culture, and serology for the diagnosis of Bordetella pertussis infection

BACKGROUND

Accurate diagnosis of Bordetella pertussis infection is difficult. Polymerase chain reaction (PCR) tests are more sensitive than culture, but the reported sensitivity is variable. We prospectively compared the performance of culture, serology, and a multiplex PCR for the detection of B. pertussis.

METHODS

A total of 193 paired nasopharyngeal (NP) swab specimens were examined by both culture and a multiplex PCR. Serology results were available in 103 patients. Medical charts of the patients with discrepant laboratory findings were reviewed and compared with the United States Centers for Disease Control and Prevention (CDC) clinical case definition.

RESULTS

Of the 193 specimens, 11 were positive on both culture and PCR, and 14 were positive on PCR only. Of the 103 specimens with serology results, 3 were positive with all three methods, and 69 were negative with all methods. Eleven of the 14 PCR-positive only cases and 6 of the 19 serology-positive only cases were defined as true pertussis cases according to an expanded standard which includes either (1) culture positive or (2) PCR or serology positive with clinical features fulfilling the CDC clinical case definition and the patients having received macrolides treatment for more than 10 days. The sensitivity and specificity of the multiplex PCR were 79% and 98%, respectively, while those for serology were 47% and 85%, and for culture 39% and 100%.

CONCLUSIONS

Our data confirm the superior sensitivity of the multiplex PCR in detection of B. pertussis, compared with conventional culture and serology. Clinical validation indicates that the multiplex PCR offers specific detection of B. pertussis from NP specimens.

Isolation of Salmonella enterica serotype choleraesuis resistant to ceftriaxone and ciprofloxacin

Salmonella enterica serotype choleraesuis (S choleraesuis) usually causes systemic infections in man that need antimicrobial treatment. We isolated a strain of S choleraesuis that was resistant to ceftriaxone and ciprofloxacin from a patient with sepsis. Ciprofloxacin resistance was associated with mutations in gyrA and parC, whereas the ampC gene (bla(CMY-2)), responsible for ceftriaxone resistance, was carried by a transposon-like mobile element. This element was found inserted into finQ of a potentially transmissible 140 kb plasmid, with an 8 bp direct repeat flanking the junction regions. The appearance of this resistant S choleraesuis is a serious threat to public health, and thus constant surveillance is warranted.

Molecular epidemiology of clinical isolates of methicillin-resistant Staphylococcus aureus in Taiwan

During July 2000 and October 2001, a total of 595 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) were collected from six medical centers distributed in northern, central, and southern Taiwan. Specimen sources included blood (n = 279), pus (n = 173), sputum (n = 94), body fluids (n = 21), catheter tips (n = 20), and urine (n = 8). Pulsed-field gel electrophoresis (PFGE) with SmaI digestion was used to fingerprint these isolates. A total of 31 genotypes with 97 type-subtypes were identified. Subtypes could be identified in 7 genotypes. While there were 6 to 15 genotypes in each hospital, 433 isolates (73%) were shown to belong to a major type (genotype A, with 29 subtypes). This genotype was not only the type prevailing in all six hospitals but also the predominant clone in each hospital, accounting for 46 to 89% of all isolates in each hospital. Genotype C (16 subtypes) was the second dominant genotype, accounting for 9% of all isolates, and was distributed in five hospitals. Genotypes D (11 subtypes), E (5 subtypes), and B (6 subtypes) were distributed in five, four, and three hospitals, respectively. The other 26 types (30 type-subtypes) were minor. We conclude that the majority of MRSA clinical isolates shared a common PFGE pattern, indicating the presence of a single, epidemic MRSA clone prevailing in major hospitals in Taiwan.

Extended epidemic of nosocomial urinary tract infections caused by Serratia marcescens

In recent years a significant increase in the incidence of Serratia marcescens infections was noted at the Chang Gung Memorial Hospital, Taoyuan, Taiwan. A review of laboratory (1991 to 2002) and infection control (1995 to 2002) records showed the possibility of an extended epidemic of nosocomial urinary tract infections (UTIs) caused by S. marcescens. Therefore, in 1998 and 1999, 87 isolates were collected from patients with such infections and examined and another 51 isolates were collected in 2001 and 2002. The patients were mostly elderly or the infections were associated with the use of several invasive devices. S. marcescens was usually the only pathogen found in urine cultures in our study. Neither prior infections nor disseminated infections with the organism were observed in these patients. Resistance to most antibiotics except imipenem was noted. Two genotyping methods, pulsed-field gel electrophoresis and infrequent-restriction-site PCR, were used to examine the isolates. A total of 12 genotypes were identified, and 2 predominant genotypes were found in 72 (82.8%) of the 87 isolates derived from all over the hospital. However, 63.9% of the isolates of the two genotypes were from neurology wards. A subsequent intervention by infection control personnel reduced the infection rate greatly. The number and proportion of the two predominant genotypes were significantly reduced among the 51 isolates collected in 2001 and 2002. Thus, a chronic and long-lasting epidemic of nosocomial UTIs caused by S. marcescens was identified and a successful intervention was carried out. Both a cautious review of laboratory and infection control data and an efficient genotyping system are necessary to identify such a cryptic epidemic and further contribute to the quality of patient care.

Dissemination of extended-spectrum beta-lactamase-producing Enterobacteriaceae in pediatric intensive care units

To study the growing trend of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in pediatric intensive care units (PICUs), 88 nonrepetitive ESBL-producing isolates were prospectively collected and analyzed by molecular methods during a 16-month period. The emergence and dissemination of ESBL-producing Enterobacteriaceae in PICUs are the consequence of the clonal dissemination of a few epidemic strains along with the horizontal transmission of resistance gene-carrying plasmids among bacterial organisms.

Two prevalent h alleles in para-Bombay haplotypes among 250,000 Taiwanese

Alpha(1,2)-fucosyltransferase catalyzes the transfer of fucose to the C-2 position of galactose on type II precursor substrate Gal beta1-4GlcNAc beta1-R. It plays an important biological role in the formation of H antigen, a precursor oligosaccharide for both A and B antigens on red blood cells. Aberration of alpha(1,2)-fucosyltransferase activity by gene mutations results in decreased synthesis of H antigen, leading to the para-Bombay phenotype. In this study, we collected about 250,000 blood samples in Taiwan during 5 yr and identified the subjects with para-Bombay phenotype. Then we analyzed the sequence of the alpha(1,2)-fucosyltransferase gene by direct sequencing and gene cloning methods, using the blood samples of 30 para-Bombay individuals and 30 control subjects who were randomly selected. The goals of this study were to search for new h alleles, to determine the h allele frequencies, and to test whether the sporadic theory is applicable in Taiwan. Six different h alleles (ha, 547-548 AG-del; hb, 880-881 TT-del; hc, R220C; hd, R220H; he, F174L; and hf, N327T) were observed. Two h alleles, he and hf, were newly discovered in Taiwan. The he allele has a nucleotide 522C>A point mutation, predicting the amino acid 174 substitution of Phe to Leu; the hf allele has missense mutation of nucleotide 980A>C, predicting the amino acid 327 substitution of Asn to Thr. Frequencies of the 6 alleles are ha 46.67%, hb 38.33%, hc 5.00%, hd 1.67%, he 3.33%, and hf 5.00%, respectively. These findings in the Taiwanese population confirm previous observations in other populations that the Bombay and para-Bombay phenotypes are due to diverse, sporadic, nonfunctional alleles, predominantly ha and hb, leading to H deficiency of red blood cells. In contrast to previous reports of non-prevalent associations of h alleles with para-Bombay phenotype, our results suggest a regional allele preference associated with para-Bombay individuals in Taiwan.

A novel cis-AB allele derived from the A transferase gene by nucleotide substitution C796A

The cis-AB is a very rare phenotype in the ABO blood group system. It corresponds to a special ABO allele encoding a glycosyltransferase that is capable of synthesizing both A and B antigens. Until now, gene sequences of only 3 cis-AB alleles were characterized. One was the A(1v) allele with a nucleotide substitution G803C at codon 268; the second was the B allele with a nucleotide substitution A796C at codon 266; and the third arose from a point mutation C700T at codon 234 in exon 7 of the B transferase gene. In this study, we found a novel cis-AB allele when performing paternity tests in Chang Gung Memorial Hospital in Taiwan. Although his father was O blood type, a serologically AB blood type child was confirmed as being his father's offspring on the basis of 16 microsatellite markers (99.97% plausibility for the child and father). Exons 6 and 7 of the child's ABO alleles were characterized by direct sequencing and gene cloning. The results showed that the child has one O(1) allele and the second allele is almost identical to A(1*02) allele except for a single point mutation at nucleotide position 796, where an A replaces a C and leads to a change of leucine to methionine at amino acid 266. This implies that the child's O(1) allele was inherited from his father and the other allele was inherited from his mother. In conclusion, the novel cis-AB allele reported here is derived from the A transferase gene through a nucleotide substitution C796A, which differs from the 3 previously reported cis-AB alleles.

Shigella flexneri sepsis in an infant

Shigellosis continues to be an important public health problem in developed countries, since communication in the world village has become more frequent. In addition, this disease is difficult to be prevented because only a small number of bacteria are required to cause infection, and it has exhibited steady trends towards multiple drug resistance. This report describes a 7-month-old female infant with Shigella flexneri sepsis presenting initially with a high fever, watery diarrhea, and dehydration. She was successfully treated with ceftriaxone for 7 days. This case illustrates that Shigella should be included in the differential diagnosis of sepsis associated with diarrhea particularly in young infants traveling to or living in an endemic area. The choice of antimicrobial therapy and the optimal duration for treatment should be carefully evaluated because of the emergence of multidrug-resistant Shigella.

Elevated serum chromogranin A precedes prostate-specific antigen elevation and predicts failure of androgen deprivation therapy in patients with advanced prostate cancer

BACKGROUND AND PURPOSE

Development of hormone-refractory prostate cancer (HRPC) may be due to outgrowth of neuroendocrine cells in the prostate gland. Increase in prostate-specific antigen (PSA) levels usually precedes clinical progression in patients failing hormone therapy. The timing of changes of PSA and chromogranin A (CgA) remains unclear. We analyzed serial serum levels of CgA and PSA in prostate cancer patients receiving androgen deprivation therapy (ADT).

METHODS

From October 1998 through January 2003, 90 patients with locally advanced (n = 20) or metastatic (n = 70) prostate cancer receiving ADT were enrolled. Serial serum samples for PSA and CgA assay were collected before and every 3 months during ADT. The median follow-up was 35 months (range, 20 to 52 months).

RESULTS

At least 3 serum samples were obtained during ADT in 78 patients. Among these patients, 36 (46.2%) had no PSA re-elevation (< 4 ng/mL) and their CgA remained low (< 84.6 ng/mL) throughout the treatment period. Another 17 patients (21.8%) also had low PSA (< 4.0 ng/mL) but had progressively increasing CgA. The remaining 25 patients (32%) developed HRPC. Among them, 17 showed progressive elevation in CgA (> 100 ng/mL), which was followed by PSA elevation after a median interval of 10 months. Interestingly, CgA levels decreased again upon reaching plateaus as PSA began to rise.

CONCLUSIONS

For patients with advanced prostate cancer receiving ADT, serum CgA may be a useful tumor marker that precedes PSA elevation. Elevation of CgA during ADT signals ultimate treatment failure and may have clinical implications for implementation of novel therapies.

Telithromycin and quinupristin-dalfopristin resistance in clinical isolates of Streptococcus pyogenes: SMART Program 2001 Data

This study evaluated the current status of antimicrobial resistance in clinical isolates of Streptococcus pyogenes in Taiwan as part of the SMART (Surveillance from Multicenter Antimicrobial Resistance in Taiwan) program. In 2001, 419 different isolates of S. pyogenes, including 275 from respiratory secretions, 87 from wound pus, and 31 from blood, were collected from nine hospitals in different parts of Taiwan. MICs of 23 antimicrobial agents were determined at a central location by the agar dilution method. All of the isolates were susceptible to penicillin (MIC at which 90% of the isolates were inhibited [MIC(90)], moxifloxacin > ciprofloxacin = levofloxacin = gatifloxacin > gemifloxacin) demonstrated potent activity against nearly all of the isolates of S. pyogenes tested. Thirty-two isolates (8%) were not susceptible to quinupristin-dalfopristin. Seventeen percent of isolates had telithromycin MICs of >or=1 microg/ml, and all of these isolates exhibited erythromycin MICs of >or=32 microg/ml. The high prevalence of resistance to telithromycin (which is not available in Taiwan) limits its potential use in the treatment of S. pyogenes infections, particularly in areas with high rates of macrolide resistance.

Telithromycin- and fluoroquinolone-resistant Streptococcus pneumoniae in Taiwan with high prevalence of resistance to macrolides and beta-lactams: SMART program 2001 data

There is a high prevalence of beta-lactam- and macrolide-resistant Streptococcus pneumoniae in Taiwan. To understand the in vitro susceptibilities of recent isolates of S. pneumoniae to fluoroquinolones and telithromycin (which is not available in Taiwan), the MICs of 23 antimicrobial agents for 936 clinical isolates of S. pneumoniae isolated from different parts of Taiwan from 2000 to 2001 were determined by the agar dilution method. Overall, 72% of isolates were not susceptible to penicillin (with 61% being intermediate and 11% being resistant) and 92% were resistant to erythromycin. Telithromycin MICs were >or=1 microg/ml for 16% of the isolates, and for 99% of these isolates the MICs of all macrolides tested were >or=256 microg/ml; all of these isolates had the constitutive macrolide-lincosamide-streptogramin B phenotype. Eighty-eight percent of the isolates were resistant to three or more classes of drugs. The ciprofloxacin MICs were >or=4 microg/ml for six (0.6%) isolates from five patients collected in 2000 and 2001, and the levofloxacin MICs were >or=8 microg/ml for five of these isolates. Seven isolates for which ciprofloxacin MICs were >or=4 microg/ml, including one isolate recovered in 1999, belonged to three serotypes (serotype 19F, five isolates; serotype 23A, one isolate; and serotype 23B, one isolate). The isolates from the six patients for which ciprofloxacin MICs were >or=4 microg/ml had different pulsed-field gel electrophoresis profiles and random amplified polymorphic DNA patterns, indicating that no clonal dissemination occurred over this time period. Despite the increased rate of fluoroquinolone use, the proportion of pneumococcal isolates for which ciprofloxacin MICs were elevated (>or=4 microg/ml) remained low. However, the occurrence of telithromycin resistance is impressive and raises concerns for the future.

Molecular epidemiology of Salmonella enterica serovar Enteritidis isolated in Taiwan

Incidence of Salmonella enterica serovar Enteritidis infection seems to be on the rise in Taiwan, and therefore, the characteristics of the isolate, including genotypes, were epidemiologically investigated. Of the 71 clinical strains isolated in 1997-1999, 61 (86%) remained susceptible to the eight antibiotics tested, while the remaining ten, eight of which were isolated in 1999, were resistant to one to three of the agents including three multiply resistant strains. The majority, 69 or 97% of the isolates, harbored a 60-kb spvC gene-carrying virulence plasmid and 12 of them harbored one or two additional various-sized plasmids. Strains with more than one plasmid were isolated mostly in 1999. Pulse-field gel electrophoresis (PFGE) revealed three major genotypes (Types A, B and C), in which type A was the predominant type. Of the 68 Type A, which contained 8 subtypes, 59 (83%) belonged to only two subtypes. Similar results were obtained with a PCR-based typing method, the infrequent-restriction-site (IRS) PCR. All four methods detected types that were rarely seen before and most of these were of recent isolates, indicating that these unusual types were new or strains of foreign origin. Though all four methods discriminated types well, PFGE and IRS-PCR showed higher sensitivity for classification. Between the two, the latter, though less discriminatory than PFGE, seems the method of choice, since it is simpler, less time-consuming and above all easy to perform.

In vivo acquisition of ceftriaxone resistance in Salmonella enterica serotype anatum

The emergence of resistance to antimicrobial agents within the salmonellas is a worldwide and severe problem. A case of treatment failure due to the emergence of resistance to ceftriaxone in Salmonella enterica serotype Anatum was studied. S. enterica serotype Anatum and Escherichia coli, both of which are susceptible to ceftriaxone, were initially isolated from a diabetic patient hospitalized for the treatment of wound and urinary tract infections. Resistant S. enterica serotype Anatum and E. coli strains were isolated concomitantly 2 weeks after the initiation of ceftriaxone therapy. The patient eventually died of a sepsis caused by the ceftriaxone-resistant salmonella. PCR, nucleotide sequence analysis, and DNA-DNA hybridization identified a bla(CTX-M-3) gene located on a 95.1-kb plasmid from the ceftriaxone-resistant isolates of S. enterica serotype Anatum and E. coli. The plasmid was proved to be conjugative. Molecular fingerprinting showed that the susceptible and resistant strains were genetically indistinguishable. The emergence of resistance to ceftriaxone in S. enterica serotype Anatum was due to the in vivo acquisition of a plasmid containing the bla(CTX-M-3) gene and was the cause for treatment failure in this patient.

Elevated cell-free serum DNA detected in patients with myocardial infarction

BACKGROUND

Cell-free DNA is detectable in the circulation. Increased cell-free DNA has been detected in cancer patients and individuals with trauma. We want to know whether patients with myocardial infarction (MI) also have increased cell-free DNA in their blood.

METHODS

We used a QIAamp blood kit for DNA extraction from serum and the PicoGreen DNA kit for quantification. DNA patterns of serum DNA were established by gel electrophoresis on 2.5% metarphor gel.

RESULTS

The average serum DNA in MI patients (N=55) was 511+/-398 ng/ml, more than 10-fold higher than normal (36.3+/-23.8 ng/ml, n=274). Patients with increased CK-MB (>4%) were associated with highly increased concentrations of cell-free DNA (93.4%). There was no correlation between the concentration of cell-free DNA and the concentrations of CK-MB, troponin I and C-reactive protein. In serial specimens, we found that the cell-free DNA rose early, but peaked behind CK-MB. A slightly diffused DNA ladder could be found with pooled cell-free DNA from MI patients by electrophoresis with the smallest DNA band at only a few hundred base pairs.

CONCLUSIONS

Cell-free DNA in MI patients is increased in patients diagnosed with MI, and may complement troponin and CK-MB in a multiple marker test format.

Outbreak of Acinetobacter baumannii bacteremia in a neonatal intensive care unit: clinical implications and genotyping analysis

BACKGROUND

Outbreaks of sepsis associated with have been rarely reported in neonatal intensive care units (NICUs). We describe such an outbreak in a NICU, and the results of molecular epidemiologic investigations are presented.

MATERIALS AND METHODS

Between August and September 2000, 6 premature infants hospitalized in a pediatric NICU developed sepsis. Three additional cases had infections during November and December. For an environmental culture survey, 94 environmental specimens and hand washings of all 43 health care workers involved in this unit were examined for the presence of this organism. Two genotyping methods, pulsed field gel electrophoresis of genomic DNA digested with I and infrequent restriction site polymerase chain reaction, were used to analyze the 9 bacteremic isolates and any isolates obtained from the environmental survey and the hand washings. Another 3 bacteremic isolates of collected in the same NICU in 1999 were incorporated as controls.

RESULTS

The 9 infants were premature and had birth weights of <1,500 g. Before onset of sepsis 9 infants had received total parenteral nutrition, and 8 infants had had central venous catheters and received intrafat emulsion. Five (5.3%) environmental specimens and 10 (23.3%) hand washing specimens were positive for the organism. Except for the strain from Case 9, the results of both genotyping methods were concordant; 11 patterns were identified by infrequent restriction site polymerase chain reaction and 10 patterns by pulsed field gel electrophoresis. One major genotype was demonstrated in the first 6 bacteremic isolates as well as 3 hand washing isolates. The genotypes of the other 3 bacteremic isolates, the 3 control strains, the 5 environmental isolates and 7 other hand washing isolates were distinct from the genotype of outbreak strains.

CONCLUSION

An outbreak of bacteremia in a NICU was clearly demonstrated by the molecular epidemiologic investigation and was possibly transmitted via the hands of health care workers.

Development of ELISA on microplate for serum C-reactive protein and establishment of age-dependent normal reference range

BACKGROUND

C-reactive protein (CRP), a marker of systemic inflammation, has been proposed to predict outcome in patients with unstable angina; and elevated levels of CRP were found to be associated with an increased risk of coronary events.

METHODS

Two enzyme-linked immunosorbent assays (ELISA) of different sensitivities were developed on microplate for CRP. Both ELISA established used Dako polyclonal anti-CRP antibody for coating and Dako horse radish peroxidase (HRP)-conjugated polyclonal anti-CRP antibody for detection.

RESULTS

The sensitivity of the high and regular sensitivity ELISA was 0.16 and 0.6 mg/l, respectively. Our assays demonstrated an excellent correlation with commercial CRP assays performed on a Behring Nephelometer Analyzer II (BNII) at both regular and ultrasensitive levels, with both correlation coefficients above 0.98 and slopes of approximately 1. Using our microplate assays, we established normal reference value for serum CRP. Based on ANOVA statistical test, we found that the mean +/- S.D. was 1.3 +/- 1.27 mg/l (n=202) for normal individuals of 50-80 years and 0.43 +/- 0.42 mg/l (n=148) for the group of 20-50 years.

CONCLUSIONS

The normal serum CRP mean concentrations for two age groups were distinctively different (p value<0.001). Our study suggests two different normal cutoffs of serum CRP to be employed for individuals in different age groups.

Molecular epidemiology of nalidixic acid-resistant campylobacter isolates from humans and poultry by pulsed-field gel electrophoresis and flagellin gene analysis

To investigate the potential of poultry products as the source of human infections associated with quinolone-resistant campylobacters, 140 human and 75 poultry isolates of nalidixic acid-resistant campylobacters were collected between 1996 and 1998, and analysed by two molecular typing methods. By the analysis of restriction fragment length polymorphism of the flagellin gene, 33 distinct patterns were obtained, with 18 of which shared by both human (89%) and poultry (93%) isolates. By the pulsed-field gel electrophoresis of SmaI-restricted macrofragments, 105 different profiles were obtained, and 11 were found in both human (40%) and poultry (23%) isolates. When the two typing methods were combined, 112 unique genotypes were obtained, 11 of which were shared by both populations, including 53 (38%) human isolates and 14 (19%) poultry isolates. Although domestic poultry products are still important sources of the quinolone-resistant campylobacter infections in humans, there are other factors that might contribute to these increasing infections simultaneously. A more stringent policy in the use of antimicrobial agents in food animals can no longer be ignored.

Multicenter surveillance of antimicrobial resistance of major bacterial pathogens in intensive care units in 2000 in Taiwan

A susceptibility surveillance study of 1,274 bacterial isolates recovered from various clinical specimens from patients in intensive care units (ICUs) of five major teaching hospitals was carried out from March, 2000, to June, 2000, in Taiwan. This study demonstrated a high rate (66%) of oxacillin resistance in Staphylococcus aureus (ORSA), a high rate of nonsusceptibility to penicillin (intermediate, 50% and highly resistant, 8%), and high rates of cefotaxime nonsusceptibility for S. pneumoniae (intermediate, 29% and resistant, 4%), Enterobacter cloacae (57%), Serratia marcescens (34%), and Citrobacter freundii (60%). High rate of ceftazidime nonsusceptibility for Pseudomonas aeruginosa (22%), and high rates of imipenem nonsusceptibility for P. aeruginosa (15%) and Acinetobacter baumannii (22%) were also found. The percentage (11.9%) of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli was greater than that (11.3%) for Klebsiella pneumoniae. Rates of quinupristin-dalfopristin nonsusceptibility for S. pneumoniae (42%), Enterococcus faecium (71%), and ORSA (39%) were high, but no vancomycin-resistant enterococci were found in this study. The resistance rates of some pathogen varied by institution or type of ICUs. Surveillance for antimicrobial resistance among bacterial pathogens in hospitals, particularly in ICU settings with a preexisting higher resistance burden, is mandatory in establishing and/or modifying guidelines for empirical treatment of severe infections in ICU patients caused by these antimicrobial-resistant pathogens.