Clinical Laboratory Standards Institute Guidelines Research Articles

Clinico-microbiological study of Pseudomonas aeruginosa in wound infections and the detection of metallo-β-lactamase production.

Pseudomonas aeruginosa is a common opportunistic pathogen of humans among the Gram-negative bacilli. Clinically, it is associated with nosocomial infections like burns and surgical-site wound infections and remains a major health concern, especially among critically ill and immunocompromised patients. This is a prospective laboratory-based 2 year study conducted to isolate P. aeruginosa from wound specimens and the antimicrobial susceptibility pattern with reference to metallo-β-lactamase (MBL) production. Two hundred and twenty-four samples of P. aeruginosa isolated from wound specimens were included in the study. Antimicrobial susceptibility was done as per Clinical Laboratory Standard Institute (CLSI) guidelines. MBL-producing P. aeruginosa was detected using the EDTA disk diffusion synergy test. Statistical analysis was done using the SPSS 11 package (SPSS Inc., Chicago, IL). Out of the 224 P. aeruginosa isolates, 100% were susceptible to polymyxin B and colistin, 92·8% were sensitive to imipenem, 38% showed resistance to gentamicin followed by ceftazidime (31·69%) and meropenem (33·03). Sixteen (7·14%) isolates showed MBL production. Infection caused by drug-resistant P. aeruginosa is important to identify as it poses a therapeutic problem and is also a serious concern for infection control management. The acquired resistance genes can be horizontally transferred to other pathogens or commensals if aseptic procedures are not followed.

Salmonella Weltevreden food poisoning in a tea garden of Assam: An outbreak investigation

Background:Salmonella enterica serovar Weltevreden has been a rare cause of acute gastroenteritis occurring worldwide. Here, we report an outbreak of food poisoning in a tea garden. Objectives: To determine the aetiological agent and risk factors responsible for the outbreak and to take necessary steps for prevention of future outbreaks. Materials and Methods: Affected area was visited by a team of microbiologists for collecting stool samples/rectal swabs from affected patients. Samples were processed by culture followed by confirmation of the isolates biochemically, automated bacterial identification system, conventional serotyping and molecular typing. Water samples were also processed for detection of faecal contamination. Antimicrobial susceptibility testing was performed by Kirby–Bauer disc diffusion technique according to the Clinical Laboratory Standard Institute guidelines. Results: The isolates were confirmed as S. enterica subspecies enterica serovar Weltevreden. They were found sensitive to ampicillin, amoxycillin-clavulanic acid, ciprofloxacin, ofloxacin, norfloxacin, cefotaxime, ceftriaxone, co-trimoxazole and doxycycline. Water samples showed high-level faecal contamination. Source of outbreak was found to be drinking water contaminated with dead livestock. House to house visit was made for early diagnosis and treatment of the cases, awareness campaigning and chlorination of drinking water. Conclusions: This report emphasises the geographical distribution of this organism in Assam. As S. Weltevreden is widely distributed in domestic animals, people should be made aware of immediate reporting of any unusual death among the livestock and their safe disposal which can significantly reduce the incidence of non-typhoidal salmonellosis in the country.

Phylogenetic study of metallo-β-lactamase producing multidrug resistant Pseudomonas aeruginosa isolates from burn patients

The present study was carried out to understand the clonal relationship using enterobacteriaceae repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) among metallo-β-lactamase (MBL) producing multidrug resistant Pseudomonas aeruginosa isolates from burn victims and their susceptibility to commonly used anti-pseudomonal agents. In the present study 94 non-duplicate P. aeruginosa strains from the wound samples of burn patients were included. Identification of the isolates was done by biochemical methods and antibiotic sensitivity was done by disc diffusion method following CLSI (Clinical Laboratory Standard Institute) guidelines. By using imipenem (IPM)-EDTA disk diffusion/double disc synergy method carbapenem resistant organisms were tested for MBL. To define the clonal relationship ERIC-PCR was used. Of the 94 isolates, 18 (19.14%) were found resistant to IPM and MBL production was shown 11 (11.70%) by the IPM-EDTA disc diffusion method. From dendrogram of the ERIC-PCR profile four major clusters were obtained (A, B, C and D). Cluster B contained the majority of the isolates (6 strains 1, 4, 8, 9, 10 and 11). This study using ERIC-PCR of randomly collected isolates exhibits high genetic diversity which rules out cross contamination frequency.

KPC-2-producing Klebsiella pneumoniae in a hospital in the Midwest region of Brazil.

The emergence of β-lactamase-producing Enterobacteriaceae in the last few decades has become major challenge faced by hospitals. In this study, isolates of Klebsiella pneumoniae carbapenemase-2 (KPC-2)-producing K. pneumoniae from a tertiary hospital in Mato Grosso do Sul, Brazil, were characterized. Bacterial identification was performed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF; Bruker Daltonics, Germany) mass spectrometry. The minimum inhibitory concentrations of carbapenems were determined using the agar dilution method as recommended by the Clinical Laboratory Standards Institute guidelines. Carbapenemase production was detected using the modified Hodge test (MHT) and polymerase chain reaction (PCR), followed by DNA sequencing. Of 360 (12.2%) K. pneumoniae isolates obtained between May 2009 and May 2010, 44 (12.2%) were carbapenem nonsusceptible. Of these 44 isolates, thirty-six K. pneumoniae isolates that were positive by MHT and PCR carried the bla KPC-2 gene. Thus, KPC-2producing Klebsiella pneumoniae has been present in a Brazilian hospital located in the Midwest region since at least 2009.

Outbreak of bloodstream infection with extendedspectrum ß-lactamase-producing Klebsiella pneumoniae at a Teaching Hospital

Introduction: Klebsiella pneumoniae (K. pneumoniae) is an important hospital-acquired pathogen causing severe infections in neonatal units. Several outbreaks of infection caused by multi-drug-resistant K. pneumoniae isolates have been widely reported among neonates. The aim is to investigate an outbreak of blood stream infection caused by Extended-Spectrum ß-Lactamases (ESBL) producing K.pneumoniae in a Neonatal Intensive Care Unit (NICU) at Teaching Hospital Kandy, Sri Lanka. Materials and Methods: Blood culture samples were collected from the neonates on admission to the NICU and 2 to 3 days later on clinical suspicion of blood stream infection. The blood culture samples were processed according to the standard methods and the antibiotic susceptibility tests were carried out as per Clinical Laboratory Standards Institute (CLSI) guidelines. Results: Of the 140 blood cultures 36 were identified as Extended-Spectrum ß-Lactamases (ESBL) producing K.pneumoniae. All the isolates were susceptible to ciprofloxacin, amikacin, netilmicin, imipenem and meropenem. Twenty eight of the 36 patients responded to treatment with a combination of amikacin and meropenem. Conclusion: ESBL producing K.pneumoniae was responsible for this outbreak at the NICU. Knowing the susceptibility patterns of clinical isolates will allow the rational use of antibiotics, which is important in the treatment of infections with multi-drugresistant bacteria. J Nepal Paediatr Soc 2014;34(3):230-232 DOI: http://dx.doi.org/10.3126/jnps.v34i3.10459

Clinical pathology reference intervals for an in-water population of juvenile loggerhead sea turtles (Caretta caretta) in Core Sound, North Carolina, USA.

The loggerhead sea turtle (Caretta caretta) is found throughout the waters of the Atlantic, Pacific, and Indian Oceans. It is a protected species throughout much of its range due to threats such as habitat loss, fisheries interactions, hatchling predation, and marine debris. Loggerheads that occur in the southeastern U.S. are listed as “threatened” on the U.S. Endangered Species List, and receive state and federal protection. As part of an on-going population assessment conducted by the National Marine Fisheries Service, samples were collected from juvenile loggerhead sea turtles in Core Sound, North Carolina, between 2004 and 2007 to gain insight on the baseline health of the threatened Northwest Atlantic Ocean population. The aims of the current study were to establish hematologic and biochemical reference intervals for this population, and to assess variation of the hematologic and plasma biochemical analytes by season, water temperature, and sex and size of the turtles. Reference intervals for the clinical pathology parameters were estimated following Clinical Laboratory Standards Institute guidelines. Season, water temperature, sex, and size of the turtles were found to be significant factors of variation for parameter values. Seasonal variation could be attributed to physiological effects of decreasing photoperiod, cooler water temperature, and migration during the fall months. Packed cell volume, total protein, and albumin increased with increasing size of the turtles. The size-related differences in analytes documented in the present study are consistent with other reports of variation in clinical pathology parameters by size and age in sea turtles. As a component of a health assessment of juvenile loggerhead sea turtles in North Carolina, this study will serve as a baseline aiding in evaluation of trends for this population and as a diagnostic tool for assessing the health and prognosis for loggerhead sea turtles undergoing rehabilitation.

Current Microbial Isolates from Wound Swab and Their Susceptibility Pattern in a Private Medical College Hospital in Dhaka city

Background: Wound infection is one of the major health problems that are caused and aggravated by the invasion of pathogenic organisms where empiric treatment is routine. Objective: To isolate and identify the bacteria causing wound infection and to determine the antimicrobial susceptibility pattern.Materials and method: A total of 263 wound swab and pus samples were collected during the period of January to December 2012 from Delta Medical College and Hospital, Dhaka, Bangladesh. Swabs from the wound were inoculated on appropriate media and cultured and the isolates were identified by standard procedures as needed. Antimicrobial susceptibility testing was performed by disk diffusion method according to ‘The Clinical Laboratory Standard Institute’ guidelines. Results: In this study 220 bacterial isolates were recovered from 263 samples showing an isolation rate of 83.65%. The predominant bacteria isolated from infected wounds were Staphylococcus aureus 89 (40.45%) followed by Escherichia coli 62 (28.18%), Pseudomonas aeruginosa 34 (15.45%), Enterococci 18 (8.18%), Acinetobacter 5 (2.27%), Klebsiella 9 (4.09%) and Proteus 3 (3.36%). Staphylococcus aureus was sensitive to linezolid (94.38%), fusidic acid (91.01%), vancomycin (87.64%), amikacin (74.15%) and gentamicin (73.03%). Among the Gram negative isolates Escherichia coli was predominant and showed sensitivity to imipenem (93.54%) amikacin (83.87%) colistin (53.22%) and piperacillin and tazobactum (53.22%) and pseudomonas showed sensitivity to amikacin (73.52%), imipenem (70.58%) and colistin (70.58%). Conclusion: Staphylococcus aureus was the most frequently isolated pathogen from wound swab and the antibiotic sensitivity pattern of various isolates help to assist the clinician in appropriate selection of empirical antibiotics against wound infection. DOI: http://dx.doi.org/10.3329/dmcj.v3i1.22236 Delta Med Col J. Jan 2015; 3(1): 25-30

Prevalence and Antibiotic Sensitivity test of <i>Salmonella</i> Serovars from Enteric Fever Suspected Patients Visiting Alka Hospital, Lalitpur

Enteric fever is still an important public health problem in developing countries including Nepal. A changing antibiotic susceptibility pattern of Salmonella Typhi and Salmonella Paratyphi A has increased to a great concern. To determine the prevalence and antibiotic sensitivity pattern of S. enteric serovars Typhi and Paratyphi from blood specimen in enteric fever suspected culture positive cases. A cross-sectional study was carried out at Alka hospital, lalitpur. Blood culture samples were collected from suspected enteric fever patient and tested microbiologically by standard procedure. AST was based on Kirby disc diffusion method and results were interpreted according to Clinical Laboratory Standards Institute (CLSI) guidelines. Of total 37 (6.10%) Salmonella serotype isolated from 604 blood culture samples, 25 (67.57%) were S. Typhi and 12 (32.43%) were S. Paratyphi A. Among the culture positive cases, the incidence rate was high in male 70.27% and the age group of 21-30 years showed maximum number of growth i.e., 14 (37.8%). Among the tested antibiotics S. Typhi was fully susceptible towards Ceftriaxone. In case of S. Paratyphi A Ciprofloxacin, Cefriaxone and Cefixime showed 100% susceptibility. Resistant pattern of Salmonella serovars was seen in higher number 34 (91.9%) in the case of Nalidixic acid. Among 37 Salmonella serovars isolated six were found to be Multidrug Resistance (MDR) where four were Salmonella Typhi and two were Salmonella Paratyphi A. Ceftriaxone and Cefixime was the most effective drugs as no isolates were resistant. Ceftriaxone and Cefixime can be the better choice of antibiotic for Salmonella isolates and remains the last drug of choice for S. Typhi and S. Paratyphi A which are also resistant to the first line agents.

Morning Serum Basal Cortisol Levels Are Affected by Age and Pubertal Maturation in School-Aged Children and Adolescents

Background: The same reference values for cortisol have been used for adults and children, but laboratory results obtained from an adult population might not be suitable for pediatric patients. Aims: To determine morning serum basal cortisol levels in children and adolescents. Methods: The study was conducted on 120 suitable reference individuals, healthy Brazilian children and adolescents from both genders aged 4-19 years old. The method used for cortisol assessment was the chemiluminescent enzyme immunoassay (VITROS® 5600 MicroWell; Johnson & Johnson, High Wycombe, UK, 2009), and the kit reference interval was 4.46-22.7 μg/dl (122.7-626.2 nmol/l). The setting limits were calculated according to the Clinical Laboratory Standards Institute guidelines. Results: The morning serum basal cortisol levels increased with age and pubertal maturation, but there were no differences based on gender. The cortisol reference values were established based on the 2.5th and 97.5th percentiles as 2.97 μg/dl [81.9 nmol/l, 90% confidence interval (CI) 1.44-3.69 μg/dl] and 23.4 μg/dl (645.5 nmol/l; 90% CI 16.3-26.4 μg/dl), respectively. Conclusions: The assessment of the morning serum basal cortisol levels showed a unique pattern, with a different lower limit for the cohort compared to current values established for adult subjects.

A clinico-bacteriological study of lacrimal regurgitate in cases of chronic dacryocystitis in a referral hospital in Madhya Pradesh

Background: Chronic dacryocystitis is an inflammation of the lacrimal sac which usually occurs because of the obstruction of the nasolacrimal duct. Objective: The primary objective of the study was to know its clinico-bacteriological profile. Materials and Methods: This prospective observational study was carried out over a period of one year to know the current bacterial flora involved in chronic dacryocystitis. All specimens were processed for isolation and identification of bacterial pathogens according to the standard microbiological techniques. The antibiotic susceptibility pattern was done by Kirby-Bauer disc diffusion method according to the Clinical Laboratory Standards Institute guidelines. Results: Among total 100 cases of chronic dacryocystitis, the highest percentage of infections in relation to age was noted in the age group of 50-60 years and the prevalence rate was higher in female patients compared with male. Out of total chronic dacryocystitis cases, 72% cases were found to be culture positive. Among positive culture, gram positive organisms were higher than that of Gram-negative. Staphylococcus epidermidis was the most frequently isolated and Streptococcus pyogenes was least isolated. The highest percentage of positive samples was found in the mucopurulent discharge followed by extensive purulent and clear fluid, respectively. In Gram-positive isolates, chloramphenicol was the most sensitive followed by cefazolin, ciprofloxacin, ofloxacin, cephalexin, vancomycin, gentamycin, and tobramycin, respectively, whereas in Gram-negative isolate, chloramphenicol and nalidixic acid were equally effective followed by ofloxacin, gentamycin, cephalexin, cefazolin and ciprofloxacin, respectively. Conclusion: S. epidermidis was the most frequently isolated bacteria, and chloramphenicol was the most susceptible drug in Gram-positive and Gram-negative bacteria.

Performance Evaluation of the Elecsys Neuron-Specific Enolase Assay

This article is available from http://www.labmedonline.org 2015, Laboratory Medicine Online This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Background: Neuron-specific enolase (NSE) is an enzyme specifically found in neurons and neuroendocrine tissue. It is a common marker for small cell lung cancer diagnosis and is also useful as a predictor of brain damage. This study evaluates the performance of Elecsys NSE (Roche Diagnostics, Switzerland), an electrochemiluminescent immunoassay. Methods: The precision, linearity, limit of detection, and reference interval of the Elecsys NSE, as well as the correlation between Elecsys NSE and ELSA-NSE (Cis-Bio International, France) were evaluated in accordance with the Clinical Laboratory Standards Institute (CLSI) guidelines. PreciControl Tumor Marker (Roche Diagnostics), patient sera, and sera from healthy individuals were used for the analysis. Results: The measured coefficient of variation for the assay was below 3%, and it demonstrated linearity from 0.20 to 234.5 ng/mL. The detection limit was 0.032 ng/mL and the reference interval ranged from 0.05 to 16.3 ng/mL. Compared with the ELSA-NSE assay, the correlation coefficient was 0.9128. Conclusions: The Elecsys assay showed suitable precision, linearity, limit of detection and reference range for clinical laboratory use; however, the correlation coefficient of Elecsys NSE as compared to ELSA-NSE was below 0.975. This result may be associated with the use of different monoclonal antibodies in the two different NSE assays. Elecsys NSE demonstrated a high sensitivity without the use of radioactive reagents; therefore, Elecsys NSE will be quite useful for NSE analysis in the clinical laboratory setting.

Evaluation of the Analytical Performance of the Modified Enterprise Point-of-Care Blood Gas and Electrolyte Analyzer in a Pediatric Hospital

Arterial blood gas testing is an essential component that directs the evaluation of a patient’s general condition, especially in the emergent setting. We evaluated the analytical performance of the modified Enterprise point-of-care (EPOC) blood gas and electrolyte analyzer system with respect to precision and accuracy and compared our results with those obtained using the point-of-care i-STAT method and the criterion standard ABL 835 Radiometer blood gas analyzer in a pediatric hospital. Evaluation studies were performed as per the Clinical Laboratory Standards Institute guidelines and included intra-assay and interassay precision and accuracy, linearity, and concordance analyses with i-STAT and ABL 835 Radiometer. Intra-assay and interassay coefficient of variation for each analyte was calculated and was less than 6% for all analytes in the ranges tested including pH, Po2, Pco2, Na+, K+, Ca2+, glucose, lactate, and hematocrit, Cl−, and creatinine. All of the analytes were linear across the reportable range. For the methods comparison of EPOC system with the i-STAT method, using 40 samples, the correlation coefficients were r > 0.94 for all analytes with the exception of Ca2+ (r = 0.61). For the methods comparison of EPOC system with the criterion standard ABL 835 Radiometer on 40 samples, the correlation coefficients were higher than 0.97 for all analytes with the exception of hematocrit and hemoglobin (r = 0.8). Thus, in our pediatric hospital setting, the EPOC system showed excellent precision and accuracy and compared favorably with the i-STAT and ABL 835 Radiometer assay results. These findings, together with the low cost, room temperature storage of test cards and availability of metabolites such as lactate, glucose, and creatinine along with the wireless connectivity of the EPOC system, provide an operational advantage over other point-of-care blood gas analyzers currently available.

In vitro activity of fosfomycin tromethamine against extended spectrum beta-lactamase producing urinary tract bacteria.

To determine the in vitro activity of Fosfomycin tromethamine against extended spectrum beta-lactamase producing uropathogens. Experimental study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from October 2011 to October 2012. A total of 381 culture positive ESBL producing isolates from 2400 urine samples submitted over a period of one year were included in this study. Identification of isolates was done by standard biochemical profile of the organisms. The antimicrobial susceptibility of culture positive isolates was performed by disk diffusion method as recommended by Clinical Laboratory Standard Institute guidelines (CLSI). The antimicrobial activity of Fosfomycin to various isolates revealed that 93% of E. coli, 64% Klebsiella spp. 50% Proteus spp. 75% Enterobacter cloacae, 100% Citrobacter freundii, 100% Burkholderia spp. 100% Serratia spp. and 50% Stenotrophomonas maltophilia were susceptible to this chemical compound. Fosfomycin showed excellent effectiveness to most of the common ESBL producing bacteria such as E. coli, Klebsiella and Proteus spp.

Abstract 13313: First Report of the New Point-of-Care TEG: a Multicenter Validation Study of the CORA® System

Background: Thrombelastography (TEG) is an established but labor intensive method for assessing global hemostasis for the management of bleeding and thrombotic risk in surgical, cardiovascular, and trauma patients. We performed the initial validation study of the first true point-of-care TEG, the CORA® (COagulation Resonance Analyzer or TEG-6S system). CORA uses resonance-frequency viscoelasticity measurements and a disposable multi-channel microfluidic cartridge to assess hemostasis and response to antiplatelet therapy. Methods: TEG assays (n=5,100) were performed from the blood of healthy volunteers (n=160) and patients undergoing coronary revascularization (n=300) collected at 3 hospitals. Quality controls were also assayed. The performance of the TEG-6S system was compared with the conventional TEG 5000 system in accordance with Clinical Laboratory Standards Institute Guidelines. Results: Regression analysis demonstrated a strong correlation (R) between the two systems by all standard measures and a lower coefficient of variation (CV %) with the CORA system at all hospitals (Table). Receiver operating characteristic (ROC) curve analysis showed an excellent correlation between platelet mapping methods (AUC≥0.90, p<0.001) and there was a substantial agreement for measuring antiplatelet response to aspirin (k=0.67, agreement=87%) and P2Y12 inhibitors (k=0.69, agreement=86%). Conclusion: The new point-of-care TEG-6S system is associated with improved precision, greater ease of use, and a strong correlation as compared to the conventional TEG 5000 system. The TEG-6S will facilitate future trials of personalized antiplatelet therapy and improve the assessment of bleeding and thrombotic risk in cardiovascular, surgical, and trauma patients.

Antimicrobial susceptibility pattern of bacteria isolated from patients with urinary tract infection.

To determine the antimicrobial susceptibility pattern of bacterial pathogens in the patients of urinary tract infection reporting at a tertiary care hospital. Laboratory based study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from January to December 2012. A total of 440 culture positive bacterial isolates from 1110 urine samples; submitted over a period of one year were included in this study. Identification of bacterial isolates was done by standard biochemical profile of the organisms. The antimicrobial susceptibility of culture positive bacterial isolates was performed by disk diffusion method as recommended by Clinical Laboratory Standard Institute guidelines (CLSI). Out of the 440 culture positive urine samples, 152 (34.6%) were from indoor patients whereas 288 (65.4%) from outdoor patients. Gram negative bacteria accounted for 414 (94%) of the total isolates while rest of the 26 (6%) were Gram positive bacteria. The most prevalent bacterial isolate was Escherichia (E.) coli 270 (61.3%) followed by Pseudomonas (P.) aeruginosa 52 (12%) and Klebsiella (K.) pneumoniae 42 (9.5%). The susceptibility pattern of E. coli showed that 96.2% of the bacterial isolates were sensitive to imipenem, 85.1% to amikacin, 80.7% to piperacillin/tazobactam and 72.6% to nitrofurantoin. In case of P. aeruginsosa, 73% bacterial isolates were sensitive to tazobactam/piperacillin, 69.2% to sulbactam/cefoperazone and 65.38% to imipenem. The antibiogram of K. pneumoniae has revealed that 76.1% of the bacterial isolates were sensitive to imipenem and 52.3% to piperacillin/tazobactam. Nitrofurantoin and imipenem were the most effective antimicrobials amongst the Enterococcus spp. as 92.3% showed susceptibility to this bacterial isolate. Majority of the bacterial isolates were sensitive to imipenem and piperacillin/tazobactam while susceptibility to most of the commonly used oral antibiotics was very low. Among the oral antimicrobials, nitrofurantoin showed good susceptibility against Enterobacteriaceae family and Gram positive organisms.

원유시료 중 메티실린 내성 황색포도알균의 분포 및 내성 유전자 특성 분석

원유시료에서 분리한 methicillin 내성 황색포도알균의 분표율과 내성유전자의 분석을 분자수준에서의 실시하였다. 총 698종의 원유시료에서 286개의 포도알균속 세균을 Staphylococcus Medium 110을 이용하여 분리 후 Vitek 2 system을 이용하여 동정한 결과 94개의 황색포도알균을 확인하였다. 94개의 황색포도알균 중 총 7개의 균에서 methicillin 내성 mecA 유전자가 존재함을 확인하였다. Methicillin-resistant Staphylococcus aureus (MRSA)로 확인된 7 균주에 대해 수종의 항생제에 대한 감수성 시험, staphylococcal cassette chromosome mec (SCCmec) typing, 및 병독소유전자인 Panton-Valentine Leukocidin (pvl)유전자를 분석하였다. 그 결과 7종의 mecA 양성 MRSA 모두 ampicillin과 oxacillin에 내성이었으며 teicoplanin, vancomycin 및 ciprofloxacin에는 모두 감수성임을 확인하였다. 한편 SCCmec typing결과 7균 중 1균주는 SCCmec type II로 확인되었고 6균주는 SCCmec type IV로 확인되었으며 병독소 유전자인 pvl유전자는 검출되지 않았다. This study was investigated to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) isolated from raw milk samples and to further study on the molecular characteristics of the MRSA isolates. Using Staphylococcus Medium 110, Staphylococcus spp. were isolated from raw milk samples and further identification was carried by Vitek2 system. Minimum inhibitory concentrations (MICs) of antibiotics were conducted by serial dilution method according to the Clinical Laboratory Standards Institute (CLSI) guideline. For the detection of resistance genes and molecular characterization, PCR reaction was performed by gene specific primers and followed by DNA sequencing. Of the 698 milk samples, 94 Staphylococcus aureus (S. aureus) were identified (94 S. aureus/286 Staphylococcus spp.). Of the 94 S. aureus, seven isolates have mecA, a methicillin resistant gene. mecA positive seven isolates were then characterized by staphylococcal cassette chromosome mec (SCCmec) typing, and Panton-Valentine Leukocidin (pvl) gene using PCR. All of mecA positive isolates were resistant to ampicillin and oxacillin, but sensitive to teicoplanin, vancomycin and ciprofloxacin. One of seven isolates was SCCmec type II and six isolates were type IV and all seven isolates were pvl gene negative.

NMR measurement of LDL particle number using the Vantera® Clinical Analyzer

BackgroundThe Vantera Clinical Analyzer was developed to enable fully-automated, high-throughput nuclear magnetic resonance (NMR) spectroscopy measurements in a clinical laboratory setting. NMR-measured low-density lipoprotein particle number (LDL-P) has been shown to be more strongly associated with cardiovascular disease outcomes than LDL cholesterol (LDL-C) in individuals for whom these alternate measures of LDL are discordant. ObjectiveThe aim of this study was to assess the analytical performance of the LDL-P assay on the Vantera Clinical Analyzer as per Clinical Laboratory Standards Institute (CLSI) guidelines. ResultsSensitivity and linearity were established within the range of 300–3500nmol/L. For serum pools containing low, medium and high levels of LDL-P, the inter-assay, intra-assay precision and repeatability gave coefficients of variation (CVs) between 2.6 and 5.8%. The reference interval was determined to be 457–2282nmol/L and the assay was compatible with multiple specimen collection tubes. Of 30 substances tested, only 2 exhibited the potential for assay interference. Moreover, the LDL-P results from samples run on two NMR platforms, Vantera Clinical Analyzer and NMR Profiler, showed excellent correlation (R2=0.96). ConclusionsThe performance characteristics suggest that the LDL-P assay is suitable for routine testing in the clinical laboratory on the Vantera Clinical Analyzer, the first automated NMR platform that supports NMR-based clinical assays.

Antimicrobial susceptibility of Gram-negative bacteria causing intra-abdominal infections in China: SMART China 2011

Background The Study for Monitoring Antimicrobial Resistance Trends program monitors the activity of antibiotics against aerobic and facultative Gram-negative bacilli (GNBs) from intra-abdominal infections (IAIs) in patients worldwide. Methods In 2011, 1 929 aerobic and facultative GNBs from 21 hospitals in 16 cities in China were collected. All isolates were tested using a panel of 12 antimicrobial agents, and susceptibility was determined following the Clinical Laboratory Standards Institute guidelines. Results Among the Gram-negative pathogens causing IAIs, Escherichia coli (47.3%) was the most commonly isolated, followed by Klebsiella pneumoniae (17.2%), Pseudomonas aeruginosa (10.1%), and Acinetobacter baumannii (8.3%). Enterobacteriaceae comprised 78.8% (1521/1929) of the total isolates. Among the antimicrobial agents tested, ertapenem and imipenem were the most active agents against Enterobacteriaceae, with susceptibility rates of 95.1% and 94.4%, followed by amikacin (93.9%) and piperacillin/tazobactam (87.7%). Susceptibility rates of ceftriaxone, cefotaxime, ceftazidime, and cefepime against Enterobacteriaceae were 38.3%, 38.3%, 61.1%, and 50.8%, respectively. The leastactive agent against Enterobacteriaceae was ampicillin/sulbactam (25.9%). The extended-spectrum β-lactamase (ESBL) rates among E. coli, K. pneumoniae, Klebsiella oxytoca, and Proteus mirabilis were 68.8%, 38.1%, 41.2%, and 57.7%, respectively. Conclusions Enterobacteriaceae were the major pathogens causing IAIs, and the most active agents against the study isolates (including those producing ESBLs) were ertapenem, imipenem, and amikacin. Including the carbapenems, most agents exhibited reduced susceptibility against ESBL-positive and multidrug-resistant isolates.

Comparision of Antibiotic Susceptility of Levofloxacin with Other Commonly Tested Antibiotics Against Salmonella Enterica Serovar (Typhi And Paratyphi A)

Background: Increasing antibiotic resistance of bacteria is a global problem. Fluoroquinolones are recommended as first line therapy for children and adults infected with Salmonella enterica serovar Typhi and Paratyphi A. The purpose of this study was to compare the antibiotic susceptibility pattern of different classes of antibiotics with levofloxacin from blood samples of suspected enteric fever patients visiting Birhospital, Kathmandu. Methods: Antibiotic susceptibility test was performed by Kirby-Bauerdisc diffusion method as per Clinical Laboratory Standards Institute guideline. Results: Among 50 isolates of Salmonella enterica, 39 (78%) were S.Typhi and 11 (22%) were S. Paratyphi A. All the isolates were tested against antibiotics, and all isolates were found sensitive to chloramphenicol and ceftriaxone whereas 3 isolates of S. Typhi were resistant to ciprofloxacin and 1 was resistant to levofloxacin. Fluoroquinolone resistant S. ParatyphiA was not observed. Among the 10 (20%) multi drug resistant isolates, only 1 isolate was resistant to levofloxacin which was S. Typhi. Both S.Typhi (96.7%) and S. Paratyphi A (89.4%) were resistant to Nalidixic acid. Conclusion: High level of nalidixic acid resistance and even some fluoroquinolone resistance showed that the treatment of the enteric fever cannot be relied on the fluoroquinolones. Nepal Journal of Medical Sciences | Volume 03 | Number 01 | January-June 2014 | Page 19-21 DOI: http://dx.doi.org/10.3126/njms.v3i1.10344

English

BACKGROUND: Acinetobacter species are one of the most frequent nosocomial pathogen causing bacteremia, urinary tract infection, secondary meningitis, skin and soft tissue infections and in particular nosocomial pneumonia with high mortality rate. The infections due to these are often difficult to treat due to their high antibiotic resistance. AIMS: To Study the prevalence and resistance pattern of Acinetobacter species in hospitalized patients of Era's Lucknow Medical College and Hospital (ELMCH), Lucknow. MATERIALS AND METHODS: Total number of 1850 samples were taken from patients admitted in wards of different Departments of ELMCH from Sep 2012 to Sep 2013. Identification of isolates was done by colony characteristics and biochemical reactions. The resistance patterns of these isolates were studied using various antibiotics by Kirby-Bauer disc diffusion test as per CLSI (Clinical Laboratory Standard Institute) guidelines. RESULTS AND CONCLUSION: 46 isolates were identified as Acinetobacter species. High level of resistance was observed for most of the antibiotics tested. More than 80% of isolates were resistant to amikacin, gentamycin, ceftriaxone, ciprofloxacin and tetracycline. 30.43% of isolates were resistant to cefoperazone/sulbactum and resistance to imipenem and colistin was 23.91% and 19.56% respectively. Acinetobacter species has become a worldwide concern as a cause of serious nosocomial infections. The emergence of increasingly resistant strains causing such infections has become a public health problem. Their early detection is necessary for timely implementation of strict infection control practices and judicious treatment with susceptible antimicrobials.