Clinical Characteristics and Antimicrobial Susceptibility Trends in Citrobacter Bacteremia: An 11-Year Single-Center Experience

BACKGROUND@#Recently, Citrobacter freundii bacteremia outbreak in a neonatal intensive care unit has attracted public attention in Korea. However, Citrobacter bacteremia is uncommon and usually occurs in patients with underlying diseases such as malignancy and hepatobiliary diseases. Increase in resistance and emerging of multidrug resistance among Citrobacter species have gradually been reported. The aim of this study was to investigate the clinical characteristics and outcome of C. freundii and non-freundii bacteremia and antimicrobial susceptibility trends.@*MATERIALS AND METHODS@#We reviewed the medical records of patients with Citrobacter bacteremia at St. Mary's Hospital, from 2007 to 2017.@*RESULTS@#A total of 43 patients with a median age of 72 (24-93) years was identified and 90.7% of them had comorbidities. Twenty-nine (67.4%) patients had C. freundii bacteremia while 14 had non-freundii bacteremia (six of C. braakii, five of C. koseri, two of C. amalonaticus and one of C. youngae). A total of 26 (51.2%) patients had community-acquired infection and intra-abdominal infection including hepatobiliary tract was the most common portal of entry (24/43, 55.8%). Moreover, hepatobiliary tract was the leading primary site of nosocomial infection (9/17, 52.9%). Polymicrobial bacteremia was observed in 21 (48.8%) patients. The percentages of Citrobacter species susceptible to ampicillin, amikacin, aztreonam, cefazolin, cefoxitin, cefotaxime, cefepime, piperacillin-tazobactam, ciprofloxacin, and imipenem were 9.5%, 97.6%, 73.8%, 9.5%, 14.3%, 71.4%, 92.9%, 83.3%, 83.3% and 100%, respectively. The resistance rate did not increase during the study period. Of 39 patients treated with antibiotics, 36 (92.3%) received appropriate empirical antibiotics. Overall mortality was 18.6%. High Charlson comorbidity index and Pitt bacteremia score were significant risk factors for death in univariate analysis and showed trends in the multivariate analysis. No significant difference in clinical features and antimicrobial susceptibility rate was observed between C. freundii and non-freundii bacteremia.@*CONCLUSION@#Citrobacter bacteremia was predominant in the elderly with comorbidities, while no pediatric case was observed. Hepatobiliary tract is the leading primary focus of bacteremia both in community-acquired and nosocomial infection. The rate of susceptibility to antibiotics has not changed in the last 11 years.

Evaluation of the Vacuum Blood Collection Tube, V-Tube, a Domestic Product for Clinical Chemistry and Thyroid Hormone Assays

BACKGROUND: It is known that the blood collection tube used can cause fluctuations in laboratory test results. We compared test results obtained when blood was collected in V-tube (AB Medical, Korea), BD Vacutainer Tubes (BD, USA), and Greiner Vacuette Tubes (Greiner, USA) in clinical chemistry and thyroid hormone assays. METHODS: One hundred volunteers from three hospitals were recruited and the peripheral blood samples were collected in each of the three serum separation tubes (SSTs). These samples were used for 28 routine clinical chemistry assays and three thyroid hormone assays. The results were analyzed by the Student paired t-test and the Bland-Altman plot. For stability tests, the initial results were compared with the day 1 (24±2 hours), day 3 (72±2 hours), and day 7 (168±2 hours) results, respectively. RESULTS: The difference in the test results obtained from the samples in each tube (V-Tube vs. BD-Tube, V-Tube vs. Greiner-Tube, and BD-Tube vs. Greiner-Tube) were satisfied with the Clinical Laboratory Improvement Amendments of 1988 allowable difference ranges. Except for four analytes (low-density lipoprotein cholesterol, magnesium, potassium, and thyroid-stimulating hormone), all analytes were within the allowable critical difference range based on biological variability. The paired t-test revealed significant differences between the results of nine assays for samples in V-Tube vs. BD-Tube and seven assays for samples in V-Tube vs. Greiner-Tube, but each set of results showed good correlations. The test results on different days showed a significant difference in several assays, but they were within the allowable difference range. CONCLUSIONS: The assay results for blood samples collected in SST V-Tubes were comparable to those obtained when blood was collected in BD Tubes and Greiner Tubes, and the blood collected in V-Tubes also showed excellent results in the stability tests.

A Case of Pseudohypoparathyroidism Type Ib Caused by Aberrant Methylation in the GNAS Complex Locus

Pseudohypoparathyroidism (PHP) is a rare disorder caused by genetic and epigenetic aberrations in the GNAS complex locus resulting in impaired expression of stimulatory G protein (Gsα). PHP type Ib (PHP-Ib) is characterized by hypocalcemia and hyperphosphatemia due to renal resistance to the parathyroid hormone, and is distinguished from PHP-Ia by the absence of osteodystrophic features. An 11-yr-old boy presented with poor oral intake and cramping lower limb pain after physical activity. Laboratory studies revealed hypocalcemia, hyperphosphatemia, and increased parathyroid hormone levels. The GNAS complex locus was evaluated using the methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) assay. Gain of methylation in the NESP55 domain and loss of methylation in the antisense (AS) transcript, XL, and A/B domains in the maternal allele were observed. Consequently, we present a case of PHP-Ib diagnosed using MS-MLPA.

Direct Identification and Antimicrobial Susceptibility Testing of Bacteria From Positive Blood Culture Bottles by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry and the Vitek 2 System

BACKGROUND: We evaluated the reliability and accuracy of the combined use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) bacterial identification and Vitek 2 antimicrobial susceptibility testing (AST) for bacteria from positive blood culture bottles. METHODS: Direct identification and AST were performed in parallel to the standard methods in monomicrobial positive blood culture bottles. In total, 254 isolates grown on aerobic and/or anaerobic bottles were identified with MALDI-TOF Vitek MS (bioMerieux, France), and 1,978 microorganism/antimicrobial agent combinations were assessed. For isolates from anaerobic bottles, an aliquot of the culture broth was centrifuged, washed, and filtered through a nylon mesh. For isolates from aerobic/pediatric bottles, a lysis step using 9.26% ammonium chloride solution and 2% saponin solution was included. RESULTS: The overall correct identification rate was 81.8% (208/254) and that for gram-positive/gram-negative isolates was 73.9%/92.6%, respectively, and it was 81.8%, 87.6%, and 57.9% for isolates from aerobic, anaerobic, and pediatric bottles, respectively. Identification was not possible in 45 cases, and most of these isolates were streptococci (N=14) and coagulase-negative staphylococci (N=11). Misidentification occurred only in one case. Compared with standard methods, direct AST showed 97.9% (1,936/1,978) agreement with very major error of 0.25%, major error of 0.05%, and minor error of 1.8%. CONCLUSIONS: This simple and cost-effective sample preparation method gives reliable results for the direct identification and AST of bacteria. For the identification of streptococci and coagulase-negative staphylococci, the method should be further improved.

Loss of Heterozygosities in Five Tumor Suppressor Genes (FHIT Gene, p16, pRb, E-Cadherin and p53) in Thyroid Tumors

OBJECTIVES: To evaluate the loss of heterozygosities (LOH) of chromosomes 3p14 (FHIT gene), 9p21 (p16), 13q21 (pRb), 6q22 (E-cadherin) and 17p13 (p53) in various thyroid tumors. METHODS: Eighty thyroid tumor cases (20 follicular adenomas, 10 follicular carcinomas, and 50 papillary carcinomas) have been analyzed for the presence of LOH in chromosomes 3p14, 9p21, 13q21, 6q22, and 17p13 allelic loss, using microsatellite markers and DNA obtained from formalin-fixed paraffin-embedded archival tissues. RESULTS: LOH on 3p14 was found in 10.5%, 33.3%, and 30.4% of follicular adenomas, follicular carcinomas, and papillary carcinomas, respectively. LOH on 9p21 was detected in 6%, 44.4%, and 47.8%, respectively. LOH on pRb gene was found in 5.3%, 20.0%, and 35.4%, respectively. LOH on E-cadherin gene was found in 5.3%, 22.2%, and 43.8%, respectively. LOH on 17p13 was detected in 0%, 40%, and 45.8%, respectively. LOH in FHIT gene, p16, pRb, E-cadherin, and p53 genes were more frequently identified in follicular carcinoma and papillary carcinoma than in follicular adenoma. CONCLUSION: LOH results of the five tumor suppressor genes (FHIT gene, p16, pRb, E-cadherin, and p53) showed statistical differences between benign tumor and malignant tumor. Among papillary carcinoma, LOH in p16, E-cadherin and p53 genes well correlated with poorly differentiated grade, and LOH of E-cadherin was associated with lymph node metastasis.

Histologic Changes in the Skin with Photoaging / 대한피부과학회지

BACKGROUND: In white people, a distinction between intrinsic aging and photoaging has been well documented in histologic studies. However, no histological studies to date have attempted to announce morphological changes with photoaged skin of Koreans. OBJECTIVE: Our purpose was to compare the histologic change with advancing age between exposed skin and nonexposed skin of Koreans. METHODS: Twenty-one male volunteers between 20 and 80 years of age were recruited. The histochemical and immunhistochemical studies were performed with the skin obtained from face and buttock. RESULTS: With advancing age, there was a decreasing tendency in the epidermal thickness. However, there was no difference between exposed skin and non-exposed skin. Density of dopa-positive melanocytes was much higher in the face than in the buttock at all ages. Decline of melanocyte density with advancing age is not prominent in the facial skin. In the facial skin, accumulation of thickened degraded elastic fibers and a decrease in collagen fibers are evident with advancing age. In the facial skin, increase of acid mucopolysaccharides is also found with advancing age. CONCLUSION: Koreans, the histologic changes in the skin with photoaging are distinct from those in the skin with intrinsic aging.

The relationship between uterine prolapse and osteoporosis in postmenopausal women / 대한산부인과학회잡지

No abstract available.