Detection of Antibiotic Resistance and Biofilm-Producing Ability of Staphylococcus Species in Clinical Isolates

Background: Staphylococci are responsible for life-threatening infections in hospitals and community. Their ability to produce multiple virulence factors and antibiotic resistance is an important reason of high mortality in staphylococcal infections. Biofilm production by these organisms makes it difficult to treat. Most of the treating antibiotics are failing and making it a matter of concern. Aims?This study aims to detect the increased antibiotic resistance in biofilm-producing Staphylococcus and to compare the performance of three potential methods of detection. Methods?A total of 81 isolates of staphylococci including coagulase negative staphylococci (CoNs), methicillin resistant S. aureus (MRSA), and methicillin sensitive S. aureus (MSSA) are included in this study. After the identification, an antibiotic sensitivity test was performed. Biofilm detection was done by three different methods: Congo red agar method, tube adherence method, and microtiter plate method. Result?Out of the 81 samples, 37 CoNs, 17 MRSA, and 27 MSSA were identified. Out of them we got 43 (53%) biofilm producers by Congo red agar method, 40 (49%) by tube adherence method, and 52 (64%) producers by tissue culture plate/microtiter plate method. Most of the biofilm producers showed multiple drug resistance. Conclusion?We found out that the microtiter plate method is sensitive and reliable as compared with the other two methods. Antibiotic resistance was found to be very common in biofilm producers. This was due to the resistance developed as a result of the matrix that does not let the antibiotic bind with the organisms. This can make the treatment of Staphylococcus very difficult in the future as the rate of drug resistance is faster as compared with newly emerging antibiotics.

AN ANALYSIS OF IMPACT OF COMPUTER BANKING SERVICES: A STUDY

The Online Banking Services are increasing day by day in the banking sector in India. In this paper aims to examine the Online Banking Services of the Banking Sectors in India. In this study used to collected data from primary and secondary sources which are collected from Bank Managers, Website and other sources. The Online Banking Services such as ATM-Automated Teller Machine, Personal Computer Banking, Phone Banking and Mobile Banking, Email Banking. The researcher concludes that through effective regulation, creating awareness of the Banking Customers.

Speciation of coagulase negative staphylococci (CoNS) isolated from various clinical specimens in a tertiary care hospital of southern Rajasthan

Background: Coagulase negative staphylococci (CoNS) are a group of staph bacteria, which generally exist as normal flora of human skin and the oral flora found on mucous membranes. CoNS in immunocompromised pa?ents can cause variety of infec?ons like bacteraemia, central nervous system shunt infec?on, intravascular catheter-related infec?ons, endocardi?s, surgical site infec?ons, urinary tract infec?ons, foreign body infec?on, endophthalmi?s, peritoni?s and wound, bone and joint infec?ons as well as infec?ons in neonates. These infec?ons are difficult to treat because of the risk factors and the drug resistant nature of the organisms.Objec?ve:To find out species wise distribu?on of Coagulase nega?ve Staphylococci (CoNS) in various relevant clinical samples in our ins?tute. Materials and Method:A total of 500 CoNS strains were isolated from relevant clinical specimens. CoNS strains were isolated from variety of clinical specimens. Strains were iden?fied as CoNS on the basis of colony morphology, gram stain, catalase test and coagulase test. Conven?onal methods were used for species iden?fica?on a?er confirming isolates as CoNS. Results:The most common source of CoNS isola?on was blood (34%), followed by respiratory secre?ons (24.4%), urine (16.8%), pus (13.4%), swabs (5.4%), bodily fluid (1.4%), and others (4.6%). S.epidermidis was most frequently isolated (30.6%), followed by S.hemoly?cus (25.4%), S.hominis (12.6%), S.capi?s (12%), S.lugdunensis (11.4%) and S.cohnii (08%). Conclusion : As CoNS have become major cause of nosocomial infec?ons, there is a need for rapid iden?fica?on and specia?on of CoNS with their an?bio?c suscep?bility for be?er management of these cases and to prevent emergence of drug resistance.

Evaluation of Pathogens Causing Urinary Tract Infection and Their Sensitivity Pattern

Background: UTI constitute a major public health problem in India accounting 2nd most common infection next to respiratory tract infection. They are responsible for increasing treatment cost and significant morbidity.Aim:-To determine the incidence of UTI, evaluation of pathogens responsible and their antimicrobial susceptibility pattern in the population.Methods:Urine samples were collected from 300 patients attending the OPD Patna medical college, Patna during the period of 18 months (January 2017 to June 2018) Antimicrobial sensitivity testing was done for the bacterial isolates present in the sample by Kirby- Bauer disc diffusion method. Only those samples were taken into consideration which develops count equal to or greater than 1*105CFU/ml as indicated by Kass.Results:Out of 300 samples collected 146 (48.66%)) yielded bacterial growth. Out of 146 culture isolates E.Coli was the most common pathogen followed by klebsiella, CoNS and staphylococcus. Antibiotic sensitivity was performed on all the isolates. It was observed that highest sensitivity was 49.31% to amikacin, gentamycin (45.89%), nitrofurantoin (38.35%) meropenem (27.39%).Conclusions:It was observed that high grade of resistance to ampicillin, cotrimoxazole, ciprofloxacin, cefuroxime, chloramphenicol, cefotaxime, cefazolin, amoxicillin + clavulanic acid and gentamycin is present as a result of misuse or improper use of antibiotic in the community. Hence urine culture is necessary for the diagnostic screening of UTI before the treatment.

Research progress on identification technology of emerging infectious diseases / 公共卫生与预防医学

In recent years, the increasingly frequent contact between humans and wild animals, coupled with the continuous mutation and evolution of pathogenic microorganisms, has led to a continuous increase and frequent outbreaks in emerging infectious diseases (EIDs), which has posed big threats and challenges to the global public health. On the occasion of the next outbreak of EIDs, it is hoped that the two major questions of "what is the pathogen" and "where does the pathogen come from" can be answered accurately and quickly through the rational use of relevant technical methods, so as to timely and effectively warn and control the outbreak of EIDs from the source. This article summarizes the pathogen identification and traceability analysis techniques of current emerging infectious diseases, and discusses the advantages and disadvantages of various technologies and their respective application fields.

Mupirocin Resistance in Coagulase Negative Staphylococcus aureus Isolated from Rural Population - An Underestimated Threat?

CoNS when exposed to repeated or prolonged treatment with mupirocin ointment, may become a reservoir of high-level resistance determinants and then pass on this resistance to S. aureus. CoNS usually tends to be reservoirs of antimicrobial resistance factors, hence they generally lead to recurrence of multi-drug resistance. Hence, it is imperative to identify and discriminate the strains of S. aureus and CoNS. We wanted to analyse mupirocin resistance in coagulase negative Staphylococcus isolated from a rural population. METHODSThis study was performed in the Department of Microbiology, SMCH (Ghaziabad) among indoor as well as OPD patients of a tertiary care hospital. All coagulase negative Staphylococcus strains were taken from patient’s clinical specimens visiting the OPD or from patients getting treatment from the hospital. CoNS were identified by standard biochemical tests. An inhibition zonal area < 21 mm was considered as resistant. RESULTSMupirocin resistance was found to be 7 % in MRCoNS and 5 % in MSCoNS. MupRH and MupRL were 5 % and 7 % respectively. Only 5 (5 %) isolates showed MIC more than 512 µg / mL as described. CONCLUSIONSIn case of emergence of mupirocin resistance, other decolonization options ought to be considered.

Comparison of the Three Phenotypic Methods to Detect Biofilm Production in Coagulase Negative Staphylococci

Coagulase Negative Staphylococci species (CoNS) have been recognized as etiological agents in wide variety of infections, patients with implants and devices. CoNS has the ability to produce biofilm which is responsible for resistance to host defense mechanisms and to the antibiotics. Hence this study was undertaken to study biofilm production by the isolated species of CoNS by three different phenotypic methods and compare these methods for biofilm production.METHODSIn this cross-sectional study, 200 CoNS isolates from clinically significant samples were identified up to species level by conventional phenotypic methods. Biofilm production was detected by Tissue Culture Plate method (TCP), Standard Tube method (ST) and Congo Red Agar Plate method (CRA). Biofilm production in test strains were compared with reference strains.RESULTSOut of 200 CoNS isolates, 122 were positive by TCP method, 106 by ST method & 67 by CRA method for biofilm production. Considering TCP method as gold standard, sensitivity, specificity, PPV and NPV of ST & CRA method were found to be 86.06%, 98.71%, 99.05%, 81.91% and 54.09%, 98.71%, 98.50% and 57.89% respectively. Analysis of Kappa agreement between TCP and ST method showed good agreement while between TCP & CRA, moderate agreement. Comparison of ST and CRA method with TCP by Pearson correlation coefficient test showed strong association between ST and TCP method (p= 0.006) & poor association between TCP and CRA method. (p<0.01).CONCLUSIONSBiofilm production by TCP method was higher compared to the other methods. ST method is comparable to TCP but CRA alone cannot be considered for biofilm detection in CoNS. ST method can be used in routine as it gives reliable results with good sensitivity & specificity and is easy to perform.

Coagulase-negative staphylococci: a 20-year study on the antimicrobial resistance profile of blood culture isolates from a teaching hospital

ABSTRACT The increasing rates of nosocomial infection associated with coagulase-negative staphylococci (CoNS) were the rationale for this study, aiming to categorize oxacillin-resistant CoNS species recovered from blood culture specimens of inpatients at the UNESP Hospital das Clínicas in Botucatu, Brazil, over a 20-year period, and determine their sensitivity to other antimicrobial agents. The mecA gene was detected in 222 (74%) CoNS samples, and the four types of staphylococcal chromosomal cassette mec (SCCmec) were characterized in 19.4%, 3.6%, 54.5%, and 14.4% of specimens, respectively, for types I, II, III, and IV. Minimal inhibitory concentration (MIC) values to inhibit 50% (MIC50) and 90% (MIC90) of specimens were, respectively, 2 and >256 µL/mL for oxacillin, 1.5 and 2 µL/mL for vancomycin, 0.25 and 0.5 µL/mL for linezolid, 0.094 and 0.19 µL/mL for daptomycin, 0.19 and 0.5 µL/mL for quinupristin/dalfopristin, and 0.125 and 0.38 µL/mL for tigecycline. Resistance to oxacillin and tigecycline and intermediate resistance to quinupristin/dalfopristin were observed. Eight (2.7%) of all 300 CoNS specimens studied showed reduced susceptibility to vancomycin. Results from this study show high resistance rates of CoNS to antimicrobial agents, reflecting the necessity of using these drugs judiciously and controlling nosocomial dissemination of these pathogens.

Species distribution and clinical profiles of coagulasenegative staphylococci (CoNS) isolated from blood cultures among paediatric patients in Hospital Kuala Lumpur

@#Introduction: Coagulase-negative staphylococci (CoNS) is often considered as a culture contaminants but it can potentially be pathogenic to patients with risk factors. A combination of species identification and clinical criteria has been suggested in determining true CoNS bacteraemia. Objectives: To identify the species distribution, antibiotic susceptibility patterns and clinical profiles of CoNS isolated from blood cultures among paediatric patients in Hospital Kuala Lumpur (HKL). Methods: This study involved CoNS isolation from blood cultures of paediatric in-patients of the Paediatric Institute HKL. Isolates were identified to species level using Analytical Profile Index Staph identification strips and antimicrobial susceptibility pattern following Kirby-Bauer Disc Diffusion method. The clinical profiles of patients were obtained from their medical records. Results: Eleven CoNS species were identified from 148 isolates. Staphylococcus epidermidis was the most frequent species isolated (67.6%). The majority of the isolates showed resistance to penicillin (85.8%); while 70.3% were methicillin-resistant (MR) CoNS, which demonstrated a significant association with true infection (p=0.021). Predictors for significant CoNS infection included thrombocytopaenia, presence of predisposing factors, nosocomial infection, blood collected from peripheral vein, and CoNS isolated from two consecutive blood cultures. The most common predisposing factors for the isolation of CoNS were the presence of peripheral (54.1%) and central venous catheters (35.1%). Conclusion: CoNS can cause significant bloodstream infections. The isolation of CoNS from blood cultures should be carefully interpreted by considering the predictive factors. Local data regarding predictive factors of patients with culture-positive CoNS, species distribution and antimicrobial susceptibility pattern are useful to determine the significance of blood culture results and care management of patients

Neonatal sepsis due to coagulase negative Staphylococci: a study from Kashmir valley, India

Background: Neonatal sepsis is a leading cause of neonatal mortality and morbidity. Early diagnosis and treatment with appropriate antibiotics are important to improve the prognosis of neonatal sepsis. Coagulase-negative Staphylococci (CoNS) have emerged as prominent pathogens in the neonatal intensive care unit. These infections are rarely fatal, but they cause significant morbidity, especially among very low birth weight infants. This study was done to know the prevalence of Coagulase-negative Staphylococci in neonatal sepsis and to determine their antibiotic susceptibility pattern.Methods: A prospective study was conducted on blood samples of suspected neonatal septicaemia between August 2017 and May 2018 received at Department of Microbiology, Government Medical College, Srinagar. Blood culture was done by automated blood culture system, (BacT/Alert) and identification and antibiotic susceptibility was done by VITEK2 method.Results: Out of 356 neonates screened, there were 185 (53.4%) positive blood cultures. Among the culture positive cases, 107 (57.83%) were male and 78 (42.16%) were female. Early Onset Septicaemia cases (130 [70.27%]) were found to be three times higher than late onset Septicaemia (55 [29.72%]). Coagulase-negative Staphylococci (CoNs) (30.27%) were the most common organisms isolated followed by Acinetobacter sp (15.1%), Klebsiella sp (5.4%) S. aureus (4.8%) and E. coli (4.8%). All the isolates of CoNS were sensitive to linezolid and vancomycin and tigecycline. Methicillin resistance was seen in 84% isolates.Conclusions: Present study highlights the emergence of Coagulase-negative Staphylococci (CoNS) as predominant cause of neonatal septicaemia. Most of the isolates were resistant to methicillin which is alarming and a cause for concern.

Neonatal sepsis in a tertiary care hospital in Delhi, India: study of microbial profile and antimicrobial susceptibility pattern

Background: Sepsis is one of the most common cause of neonatal deaths globally more so in low and middle-income countries. The key to management is high degree of clinical suspicion and prompt initiation of empirical antibiotic therapy pending investigations' results. Knowledge of one's own NICU flora and antimicrobial susceptibility pattern guides in choosing correct antibiotic therapy to pediatrician. If this data is standard and comparable across different sites, then it also helps in formulating regional and National treatment guidelines. Present study was therefore undertaken to study microbial flora of present NICU and analyze their antimicrobial susceptibility pattern and formulate antimicrobial policy.Methods: Data of blood culture isolates sent from suspected cases of neonatal sepsis received from January 2017 to July 2018 was analysed by 'WHONET'.Results: One hundred ninety-three non-repeat isolates were obtained from 992 blood culture samples. Coagulase negative Staphylococcus and K. pneumoniae were the most common isolates. Non albicans Candida were responsible for majority of fungal infection. There was an outbreak of C. pelliculosa for six months. Most of the bacteria were multidrug resistant (MDR). However, except one all other Candida isolates were sensitive to antifungal drugs.Conclusions: WHO guidelines suggest use of penicillin and gentamicin for neonatal sepsis. But in present study, they were not found useful, instead amikacin, netilmicin and piperacillin-tazobactam were found useful and changes were made in antibiotic policy. Authors therefore recommend regular monitoring of antimicrobial susceptibility pattern followed by necessary changes in antibiotic policy for reasonable empirical therapy.

Bacteriological Profile and Antibiotic Susceptibility Patterns in Neonatal Septicaemia in Tertiary Care Hospital

Introduction: Neonatal septicaemia has great role in morbidityand mortality among neonates. Neonatal mortality rate hasbeen reported in India as 17 per 1000 live births as per 2016-17 data. Neonatal septicaemia may be of early onset or lateonset depending of the age of the neonates. The mostcommon bacterial agents involved are Group B Streptococcus,Klebsiella pneumoniae, CoNS, Streptococcus pneumoniae,Haemophilus influenzae etc. Diagnosis is done by manymethods but the most important and absolute mode ofdiagnosis is blood culture.Aims and Objectives: The present study is done for thedetection of bacteriological profile and their antibioticsusceptibility pattern in case of neonatal septicaemia. Earlydiagnosis and specific treatment can save the lives of manyneonates who are suffering from neonatal septicaemia.Materials and Methods: The material used for the diagnosis isvenous blood of the suspected neonates. Blood culture methodis used for the diagnosis of Neonatal septicaemia. Repeatedsubculture is done on Blood agar, Nutrient agar, andMacConkey agar plates. Confirmation of organism is donethrough different biochemical tests. The antibiotic susceptibilitytesting was performed on Muller Hinton agar (MHA) by KirbyBauer disc diffusion method for bacterial isolates, as perclinical and laboratory standards institute (CLSI) guideline.Results: Total 206 cases of suspected neonatal septicaemiawere investigated in which 142 cases are found positive. Mostcommon organism isolated was Klebsiella pneumoniae(39.44%) than Staphylococcus aureus (33.8%), otherorganisms are Escherichia coli (9.86%), CoNS (8.48%),Pseudomonas (5.63%), Enterococcus (2.82%) etc. overallincidence of Gram negative organism (54.93%) was more thanGram positive organism (45.07%). As far as antibioticsensitivity pattern was concerned most of the organism were100% sensitive to imipenem, meropenem and colistin B andresistant to Ampicillin.Conclusion: Gram negative isolates were more common thanGram positive as the causative agents of neonatal sepsis. Themost common causative organism was Klebsiella pneumoniae.The other organisms isolated were Pseudomonas aeruginosa,Staphylococcus aureus, CoNS, etc. Most of the Gram negativeisolates were sensitive to Amikacin, Gentamycin, Ofloxacin andCiprofloxacin but were highly susceptible to Meropenem,Imipenem and Collistin-B. The Gram positive isolates werebetter sensitive to Amikacin, Cephalosporin, Ciprofloxacin andClindamycin but were less sensitive or resistant to Ampicillinand Erythromycin. They showed high susceptibility toTicoplanim, Linezolid, Vancomycin and Methicillin.

Pros and cons analysis on complete public transparency of medical records of medical institutions / 中华医院管理杂志

The authors analyzed the pros and cons for complete public transparency of medical records of medical institutions and came forward with constructive suggestions. These included standardizing and streamlining the medical records writing and combining the objective and subjective disease history;strengthening quality control of medical records and paying attention to informationization of such institutions;improving laws and norms;and strengthening publicity and deepening awareness of the public.

Pros and cons analysis on complete public transparency of medical records of medical institutions / 中华医院管理杂志

The authors analyzed the pros and cons for complete public transparency of medical records of medical institutions and came forward with constructive suggestions. These included standardizing and streamlining the medical records writing and combining the objective and subjective disease history;strengthening quality control of medical records and paying attention to informationization of such institutions;improving laws and norms;and strengthening publicity and deepening awareness of the public.

A Review of Staphylococcal Cassette Chromosome mec (SCCmec) Types in Coagulase-Negative Staphylococci (CoNS) Species

Coagulase-negative staphylococci (CoNS) are considered low pathogenic organisms. However, they are progressively causing more serious infections with time because they have adapted well to various antibiotics owing to their ability to form biofilms. Few studies have been conducted on CoNS in both, hospital and community-acquired settings, especially in Malaysia. Thus, it is important to study their species and gene distributions. A mobile genetic element, staphylococcal cassette chromosome mec (SCCmec), plays an important role in staphylococci pathogenesis. Among CoNS, SCCmec has been studied less frequently than Staphylococcus aureus (coagulase-positive staphylococci). A recent study (8) conducted in Malaysia successfully detected SCCmec type I to VIII as well as several new combination patterns in CoNS species, particularly Staphylococcus epidermidis. However, data are still limited, and further research is warranted. This paper provides a review on SCCmec types among CoNS species.

Pros And Cons Of Problem-Based Learning In Medical Education: Students’ Viewpoint.

Background and Objectives: Problem-based learning (PBL) is an innovative educational approach in which the students determine what they need to learn. The present study was done to review the pros and cons of PBL, with the aim to introduce reforms in the traditional teaching methodology.Methods: A total of 200 MBBS students participated in the study. Six PBL exercises were allotted to the students and after their completion, they were asked to fill the questionnaire regarding their perceptions about PBL on a 5-point Likert scale, as well as open ended questions to elicit two reasons each for liking and disliking PBL.Results: Regarding the students’ perceptions, the mean/median scores of all the items was found to be ≥ 3, indicating the positive inclination of students towards PBL. The major favourable factors of PBL were the opportunity of group discussion (16%) and better understanding (15.8%). The major drawbacks in PBL were that preparation required more time (20.5%), inadequate discussion (12.8%) and large group size(11.0%) Interpretation and Conclusion: Students generally favour PBL, as it enhances their ability to handle and solve real-life problems; however, few of the challenges are also accompanied with it which should be looked into to improvise it.

Antibiotic Resistance Patterns and Virulence Factors of Coagulase Negative Staphylococcus Associated with Urinary Tract Infections in Bulawayo Province, Zimbabwe.

Aims: To determine the antibiotic resistance patterns and virulence factors of coagulase negative Staphylococcus (CoNS) associated with urinary tract infections (UTIs). The virulence factors assayed for were the atl E and ica AB genes. The prevalence of the antibiotic resistance gene, mec A, was also determined. Place and Duration of Study: Southern Pathology Clinical Laboratories and the National University of Science and Technology microbiology department, between December 2012 and March 2015. Methods: A total of 754 urine samples were analyzed for bacteria by standard procedures. From these, 126 isolates were positively identified as CoNS. Antimicrobial susceptibility testing of the isolated CoNS was done using the disc diffusion method.The polymerase chain reaction (PCR) was also carried out to detect the presence of the mec A, ica AB and atl E genes. Results: Antibiogram profiles showed that CoNS had high prevalences of resistance to nalidixic acid (88.1%), cotrimoxazole (72.2%) and oxacillin (69.8%).There were however high prevalences of sensitivity to nitrofurantoin (79.4%) and gentamycin (68.3%). A total of 106 (84%) isolates were resistant to three or more antibiotics and 12 multi-drug resistance patterns were observed. The most common pattern (resistance to nalidixic acid, ampicillin, oxacillin, tetracycline and cotrimoxazole) was exhibited by 33 isolates. A total of 40 CoNS isolates were then used to determine the prevalence of the mec A, ica AB and atl E genes. PCR results showed that most isolates 25/40 (62.5%) were positive for the mec A gene. The ica AB and atl E were detected in 32.5% and 25% of the isolates respectively. All isolates which were positive for both the mec A and ica AB genes showed resistance to multiple antibiotics. Conclusion: There is emerging antibiotic resistance in CoNS that cause UTI’s. The occurrence of both the mec A and ica AB genes in CoNS isolates may lead to an increase in antibiotic resistance.

Robotic Thyroidectomy: Pros and Cons of Various Surgical Approaches / 대한내분비외과학회지

Robotic thyroidectomy has been a good option in the treatment of benign and early stage differentiated thyroid cancers, with several functional benefits. In the last few years, many surgeons have established their own robotic thyroidectomy techniques, and published many reports on the feasibility, safety and benefits of their robotic procedures. Although there are many different surgical techniques, robotic thyroidectomy can be classified according to the different means of remote access to the thyroid gland. Each method has advantages and disadvantages, and surgeons have modified each procedure in an effort to eliminate its shortcomings. With the remarkable innovation of robotic instruments and patient selection based on the appropriate indications, robotic thyroidectomy may usher a paradigm shift for thyroid surgery in the near future.

Significance of Coagulase Negative Staphylococci with Special Reference to Species Differentiation and Antibiogram.

Coagulase negative staphylococci (CoNS)are part of normal human flora increasingly recognized as significant nosocomial pathogens, infection often associated with implanted devices, joint prosthesis and different indwelling devices, especially in very young, old immunocompromised patients. Aims: To identify CoNS species, their distribution and antibiotic susceptibility pattern from different clinical samples. Method: A total 185 CoNS isolates were collected from various clinical samples followed for species identification by a practical scheme adapted using simple ,useful test selected from various references. Antibiotic susceptibility done by Kirby Bauer disc diffusion method. Results: The study yield that 185 CoNS,strains were isolated out of 1514 positive cultures from various clinical specimens. Among species ; S. epidermidis was the most commonly isolated species (68.65%), followed by S. heamolyticus (16.75%),followed by S. saprophyticus(9.8%)and few other species also identified. The antibiotic susceptibility pattern against commonly used antibiotic showed multidrug resistance with more than 90% resistance to penicillin and no strains was resistance to vancomycin. The methicillin resistance was 63% among all isolates of CoNS. Conclusions: Study suggest increasing pathogenic potential of CoNS as well as emerging of drug resistance amongst them, that necessitates the need to adopt simple laboratory procedure to identify CoNS species and understand definitive therapy for CoNS isolates from various clinical samples. This scheme was able to identified 98.9% isolates up to species level.

Evaluation of fuur different dna extraction metods in coagulase-negative staphhylococci clinical isolates / Avaliacao de quatro metodos diferentes de extracao de DNA em isolados clinicos de estafilococos coagulase negativos (SCoN)

Currently there are several methods to extract bacterial DNA based on different principles. However, the amount and the quality of the DNA obtained by each one of those methods is highly variable and microorganism dependent, as illustrated by coagulase-negative staphylococci (CoNS) which have a thick cell wall that is difficult to lyse. This study was designed to compare the quality and the amount of CoNS DNA, extracted by four different techniques: two in-house protocols and two commercial kits. DNA amount and quality determination was performed through spectrophotometry. The extracted DNA was also analyzed using agarose gel electrophoresis and by PCR. 267 isolates of CoNS were used in this study. The column method and thermal lyses showed better results with regard to DNA quality (mean ratio of A260/280 = 1.95) and average concentration of DNA (), respectively. All four methods tested provided appropriate DNA for PCR amplification, but with different yields. DNA quality is important since it allows the application of a large number of molecular biology techniques, and also it's storage for a longer period of time. In this sense the extraction method based on an extraction column presented the best results for CoNS.

Atualmente, para extrair o DNA bacteriano, existem diversos métodos baseados em diferentes princípios. Entretanto, a quantidade e qualidade do DNA obtido por cada um destes métodos é variável e depende do tipo de micro-organismo em questão; os estafilococos coagulase-negativos (CoNS), por exemplo, possuem parede celular espessa difícil de lisar. O objetivo deste estudo foi comparar a quantidade e a qualidade do DNA extraído de isolados clínicos de CoNS utilizando quatro metodologias diferentes: dois protocolos caseiros e dois kits comerciais. A determinação da quantidade e da qualidade do DNA foi realizada por espectrofotometria. O DNA extraído também foi analisado em eletroforese em gel de agarose e por PCR. A concentração média de DNA foi mais alta no método de lise térmica (). Entretanto, com relação à qualidade do DNA, o kit comercial que utiliza um método de extração baseado em uma coluna de separação apresentou melhor resultado (média da relação A260/280 = 1,95). As quatro técnicas testadas forneceram DNA passível de amplificação por PCR, porém com diferentes rendimentos. A qualidade do DNA extraído de bactérias é importante, pois possibilita a realização de maior número de técnicas de biologia molecular e também armazenamento do material por maior período de tempo. Neste sentido, a técnica de extração por coluna de separação apresentou melhor desempenho frente aos CoNS.