Evaluation of in vitro susceptibility of Gram-positive pathogens from a tertiary care hospital in Singapore to a novel oxazolidinone, tedizolid, by a gradient diffusion method and broth microdilution

2018 ◽  
Vol 72 (2) ◽  
pp. 181-184
Author(s):  
Saugata Choudhury ◽  
Lee Kar Mun ◽  
Esme Ng Chu Xuan ◽  
Lee Shin Jia ◽  
Shawn Vasoo ◽  
...  

We compared the in vitro antimicrobial activities of tedizolid and linezolid on the Sensititre broth microdilution system for Gram-positive cocci isolates (n=146) from skin and skin structure infections and bloodstream infections, bronchoalveolar lavage and sputum. These pathogens included 40 methicillin-resistant Staphylococcus aureus, 38 coagulase-negative staphylococci, 20 Enterococcus faecalis and 48 beta-haemolytic Streptococcus spp. Susceptibility was simultaneously determined for 48 vanA vancomycin-resistant enterococci isolates 2013–2016 from rectal swabs (23 E. faecalis and 25 E. faecium, of which 4 were linezolid-non-susceptible). MIC90s for tedizolid were fourfold to eightfold lower than linezolid on the Sensititre and ranged from 0.12 to 0.5 µg/mL for the different pathogen groups. All isolates were susceptible to tedizolid except two vanA E. faecium strains (MICs of 1 and 2 µg/mL, respectively). Categorical and essential agreement for tedizolid were 99.48% and 92%, respectively, between Liofilchem gradient diffusion and Sensititre methods. Overall, the drug exhibited excellent activity against the surveyed Gram-positive pathogens.

2020 ◽  
Vol 12 (03) ◽  
pp. 230-232
Author(s):  
Dhruv Mamtora ◽  
Sanjith Saseedharan ◽  
Ritika Rampal ◽  
Prashant Joshi ◽  
Pallavi Bhalekar ◽  
...  

Abstract Background Blood stream infections (BSIs) due to Gram-positive pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) are associated with high mortality ranging from 10 to 60%. The current anti-MRSA agents have limitations with regards to safety and tolerability profile which limits their prolonged usage. Levonadifloxacin and its oral prodrug alalevonadifloxacin, a novel benzoquinolizine antibiotic, have recently been approved for acute bacterial skin and skin structure infections including diabetic foot infections and concurrent bacteremia in India. Methods The present study assessed the potency of levonadifloxacin, a novel benzoquinolizine antibiotic, against Gram-positive blood stream clinical isolates (n = 31) collected from January to June 2019 at a tertiary care hospital in Mumbai, India. The susceptibility of isolates to antibacterial agents was defined following the Clinical and Laboratory Standard Institute interpretive criteria (M100 E29). Results High prevalence of MRSA (62.5%), quinolone-resistant Staphylococcus aureus (QRSA) (87.5%), and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) (82.35%) were observed among bacteremic isolates. Levonadifloxacin demonstrated potent activity against MRSA, QRSA, and MR-CoNS strains with significantly lower minimum inhibitory concentration MIC50/90 values of 0.5/1 mg/L as compared with levofloxacin (8/32 mg/L) and moxifloxacin (2/8 mg/L). Conclusion Potent bactericidal activity coupled with low MICs support usage of levonadifloxacin for the management of BSIs caused by multidrug resistant Gram-positive bacteria.


1995 ◽  
Vol 6 (5) ◽  
pp. 258-262 ◽  
Author(s):  
Donald E Low ◽  

To compare the activity of cefepime, a fourth-generation cephalosporin, with several available antimicrobials, in vitro susceptibility studies were carried out on bacteria commonly associated with various infections, including sepsis. Ten tertiary care hospital laboratories in six provinces provided 1276 clinically relevant isolates of aerobic Gram-negative bacilli and Gram-positive cocci during 1993. When the activity of each of the antimicrobials was determined against all isolates submitted, cefepime, piperacillin/tazobactam, imipenem and ciprofloxacin all had minimal inhibitory concentrations for 90% of the organisms (mic90) two or more dilutions below themicresistant category. Gentamicin’smic90against all organisms tested was one dilution below themicresistant category. Themic90s of the third-generation cephalosporins, piperacillin and ticarcillin/clavulanate, forEnterobacterspecies fell in the resistant category. This is presumably due to constitutive high level chromosomal cephalosporinase production. Themic90s of cefepime forEnterobacterspecies was three or more dilutions below themicresistant category. Themic90s of all antimcrobials againstStaphylococcus aureus, with the exception of ceftazidime and piperacillin, hadmic90categories two or more dilutions below the resistant category. The activity of cefepime, piperacillin/tazobactam, imipenem, ciprofloxacin and gentamicin make them excellent candidates for the empirical therapy of serious infections due to aerobic Gram-negative bacilli andS aureus.


2020 ◽  
Vol 12 (04) ◽  
pp. 233-238
Author(s):  
Ashvini K. Yadav ◽  
Suneel Bhooshan ◽  
Allen Johnson ◽  
Dinesh P. Asati ◽  
Shashwati Nema ◽  
...  

Abstract Purpose Cutibacterium acnes (C. acnes) is an emerging pathogen that is highly resistant to antibiotics and is capable of causing persistent infections that are difficult to treat. Methods & Materials Acne vulgaris patients visiting dermatology OPD of our tertiary care hospital during the study period of 2 months were recruited. Skin swabs were collected, and the sample was processed on 5% sheep-blood agar for anaerobic culture by the GasPak method. Isolates were identified by the standard biochemical test. Antimicrobial susceptibility testing was performed for clinically relevant antibiotics by the E-strip method. The clinical response was evaluated after 1-month follow-up to the prescribed antibiotics. Results Minocycline, doxycycline, ceftriaxone, and tetracycline were the most effective antibiotics. Nonsusceptibility to clindamycin and erythromycin were observed in 11.9% and 31% isolates, respectively, with 9.5% isolates being nonsusceptible to both. For none of the antibiotics we found significant difference in the proportion of susceptible and nonsusceptible isolates between mild, moderate, and severe grades of acne vulgaris. For none of the antibiotic regimens, significant difference was observed between nonresponders and responders. Twenty-seven patients received clindamycin and among them 16 of 19 responders and 6 of 8 nonresponders yielded growth of clindamycin-susceptible isolates (p = 0.57). Conclusion We observed significant prevalence of resistant strains of C. acnes among patients with acne vulgaris. No association was observed between in vitro susceptibility results and treatment outcome.


2021 ◽  
pp. 65-67
Author(s):  
Hemendra K Sharma ◽  
Niketa Gupta ◽  
Mahesh Yadav ◽  
Aruna Vyas ◽  
Rajni Sharma

Background: Pyogenic infections can be caused by various microorganisms and may co-exist as poly microbial infections which require antibiotic therapy. The inappropriate use of antibiotics has led to major problems of MDRO's contributing to morbidity and mortality. Even though the bacteriological prole of pus samples in many studies remain the same, antimicrobial susceptibility pattern of these isolates has shown a lot of variation. This study was conducted to assess bacteriological prole of pus samples and their antimicrobial susceptibility pattern Materials and Methods:Aretrospective study was carried out from April to June 2021. 540 pus culture aerobic bacterial isolates were included. The samples were cultured on Blood and MacConkey agar. After aerobic incubation at 37oC for 18-24 hrs, organisms were identied by conventional bacteriology methods as per laboratory protocol and antimicrobial susceptibility was tested by Kirby Bauer disc diffusion method as per CLSI 2020 guideline. Results: Out of 540 pus isolates , 452(83.7%)were gram negative bacili and 88(16.3%) were gram positive cocci Pseudomonas spp. 173(31.9%), was most common gram negative isolate while S.. aureus 66(12.19%) was most common Gram positive isolate. Most of gram negative isolates were susceptible to Imipenem and Polymyxin and gram positive isolates to vancomycin and linezolid . Conclusion: To combat resistance irrational use of antibiotics should be avoided. Also regular surveillance helps in implementing better therapeutic strategies to reduce morbidity and mortality


2020 ◽  
Vol 12 (01) ◽  
pp. 56-67
Author(s):  
Amit Banik ◽  
Valarie W. Lyngdoh ◽  
Elantamilan Durairaj ◽  
Anil C. Phukan ◽  
Raghavendra Kotal

Abstract Purpose Blood is one of the most important connective tissues of human body. Bloodstream infection can range from inapparent bacteremia till fulminant septic shock with high mortality. Presence of microbes in blood whether continuously, intermittently, or transiently is a grave risk to every organ of body. Culture of blood is a vital tool to diagnose such infections. Drug susceptibility patterns help in rationalizing therapy. Objective The aim of the study is to perform bacteriological analysis and assess drug sensitivity patterns of blood culture isolates and compare in light of other associated variables. Design Retrospective observational study was conducted from January 2009 to December 2013 at a tertiary care hospital at Shillong, India. Blood samples were collected with aseptic guidelines and cultured for 7 days. Growths were identified by standard biochemical tests and subjected to sensitivity testing according to Modified Kirby Bauer disk diffusion method. Data for source of blood collection and duration of incubation were noted and compared. Results A total of 658 (11.2%) pathogens were isolated from 5,867 bacteremia-suspected patient blood specimens. Contamination was observed at the rate of 1.21%. Gram-negative organisms were the predominant pathogens recovered, Klebsiella pneumoniae being the most common. No significant difference was observed between the number of organisms isolated within or beyond 48 hours. Acinetobacter baumannii and K. pneumoniae have significantly higher chances (p < 0.05) of isolation from central line catheters compared with peripheral venipuncture. Conclusion Successful treatment of sepsis depends on early diagnosis and proper antimicrobial therapy. Local knowledge of bacteriological profile and antimicrobial sensitivity patterns helps rationalize empiric treatment strategies.


2018 ◽  
Vol 10 (03) ◽  
pp. 332-337 ◽  
Author(s):  
Amit Banik ◽  
Sanjeev H. Bhat ◽  
Abhay Kumar ◽  
Agnijeet Palit ◽  
Kandregula Snehaa

ABSTRACT PURPOSE: Bloodstream infection can range from inapparent bacteremia until fulminant septic shock with high mortality. Microorganisms present in circulating blood whether continuously, intermittently, or transiently are a threat to every organ in the body. Culture of blood is a vital tool to diagnose such infections. Drug susceptibility patterns help in rationalizing therapy. OBJECTIVE: The objective of this study was to perform bacteriological analysis and assess drug sensitivity patterns of isolates from blood stream infections. DESIGN: Retrospective observational study was conducted from May 2015 to February 2017 at a tertiary care hospital, Port Blair, India. Blood samples were collected with aseptic guidelines and cultured for 7 days. Growths were identified using standard biochemical tests and subjected to sensitivity testing according to Modified Kirby–Bauer’s disk diffusion method. Data for the source of blood collection and duration of incubation were noted and compared. RESULTS: A total of 270 (14.24%) pathogens were isolated from 1895 bacteremia suspect patient blood specimens. Contamination was observed at a rate of 1.63%. Gram-positive cocci (60.37%) were predominant organisms recovered followed by Gram-negative Bacilli (36.29%) and Yeasts (3.33%). Staphylococcus aureus, CoNS, and Acinetobacter spp. were the primary pathogens isolated. Aminoglycosides, carbapenems, and glycopeptides were the most effective drugs for treating bacteremia. CONCLUSIONS: Successful treatment of sepsis depends on early diagnosis and proper antimicrobial therapy. Local knowledge of bacteriological profile and antimicrobial sensitivity patterns helps rationalize empiric treatment strategies.


Author(s):  
KMS Mohamed Ali ◽  
K Girija

Blood stream infections are the most important and common cause of morbidity and mortality in tertiary care hospitals. Since the results are usually not available promptly a knowledge of epidemiologic and antimicrobial susceptibility pattern of blood pathogens is life saving and very useful for early treatment and recovery of patients. The aim of this study is to describe the epidemiological, bacterial profile and antimicrobial resistance pattern of bloodstream infections in a tertiary care centre.A prospective cross-sectional study was done on seven hundred and eight blood samples collected over a period of six months in the Microbiology laboratory. Blood samples collected under aseptic conditions were cultured by aerobic culture method. Identification of bacterial isolates were done using standard bacteriologic and biochemical testing methods and antibiotic sensitivity testing done by Kirby - Bauer disc diffusion method.Bacteria was isolated in 201 (28.3%) samples with highest rates among newborns 84(41.8%). The most frequent isolates were 111 (55.2%) followed by 49 (24.4%). Results showed high susceptibilities of CoNS 111 (100%) to Vancomycin, Linezolid and 51 (98%) to Meropenem. This study highlights the common prevalent bacteriological agents in bacteremia, their antibiotic susceptibility & resistance patterns. and multi drug resistant were the leading causes of septicaemia in our hospital with Vancomycin, Linezolid and Carbapenems the effective antibiotics against these pathogens respectively.


2021 ◽  
Vol 18 (4) ◽  
pp. 734-740
Author(s):  
Dharma Nagarkoti ◽  
Krishna Prajapati ◽  
Ajay Narayan Sharma ◽  
Aarogya Gyawali ◽  
Sarita Manandhar

Background: Staphylococci are posing threat due to increasing trend of antimicrobial resistance particularly methicillin. Macrolide lincosamide streptogramin B (MLSB) family of antibiotics is commonly used to treat such infections. This study was aimed to determine the prevalence of inducible clindamycin resistance and observation of erm and msr genes among Staphylococci isolated from tertiary care hospital of Nepal during July 2017 to March 2018.Methods: Staphylococci from different clinical specimens were identified and antibiotic susceptibility profile was assessed following Kirby Bauer disc diffusion method. The double disc diffusion or D-zone test as outlined in CLSI document M100-S24 was performed to examine inducible clindamycin resistant isolates. Multiplex PCR was performed for detection of erm and msr gene in isolates using specific primers for ermA, ermB, ermC, msrA and msrB genes.Results: Of the 60 Staphylococci isolates, 39 (65%) were S. aureus and 21 (35%) were coagulase negative Staphylococci (CNS) with 25 (64%) and 15 (71%) representing methicillin resistant S. aureus and CNS respectively. Constitutive and inducible MLSB phenotype was observed among 24 (40%) and 14 (23%) isolates respectively by D test. The most prevalent resistant gene was ermC (37%) followed by msrB (12%), ermB (10%) and msrA (10%). None of the isolates were found to possess ermA gene. Conclusions: The presence of constitutive and inducible MLSB as well as resistant genes among Staphylococci necessitates detection of such isolates to minimize treatment failure. The result from this study may help elucidate the predominant resistant characteristics in clinical Staphylococci isolated from tertiary care hospital of Nepal.Keywords: D test; erm gene; MLSB; msr gene; staphylococci.


Author(s):  
Abigail R. Sopia ◽  
Pushpa Innocent D. Joseph ◽  
M. Kalyani ◽  
B. Ananthi ◽  
Suresh Dhanaraj ◽  
...  

Genital infections and subsequent vaginosis diagnosed through high vaginal swab in women is caused due to fungi or bacteria. The presented study focused on determining the types, numbers and antibacterial susceptibility pattern of aerobic bacteria causing vaginosis in 147 female patients attending infertility centre in Chennai, Tamil Nadu, India. Candida spp. caused 17% of infections with 15.7% of vaginosis caused by E.coli, Klebsiella spp., Acinetobacter spp., Citrobacter spp. and Gram positive cocci – Methicillin Sensitive Staphylococcus aureus (MSSA), Coagulase Negative Staphylococci(CONS), Staphylococcus aureus and Enterococcus spp. causing 12.9% of vaginitis in the study population. A total of 20 different antibiotics – cell wall inhibitors, protein synthesis inhibitors and nucleic acid synthesis inhibitors; were tested to determine the response of bacterial isolates by Kirby-Bauer disc diffusion method. The study result determined that the most effective drug for treating Gram positive bacterial vaginitis as per CLSI guidelines based on susceptibility pattern as: Linezolid(100%), Gentamycin(91.6%), Amikacin(87.5%),Erythromycin(79.2%), Co-Trimoxazole(72.2%), Ciprofloxacin(65.6%) and least Chloramphenicol(44.3%). High level gentamycin(83.3%) was found to be effective in treating Enterococci. The descending order of susceptibility of Gram negative aerobacteria causing vaginitis as per CLSI guidelines are: Amikacin(87.5%), Gentamycin(82.5%), Cefoperazone sulbactam (76.3%), Ciprofloxacin(68.5%), Ceftazidime(62.5%) and least Amoxyclav(25%).All Gram negative bacteria tested were susceptible to– Imipenem and Meropenem as well as Chloramphenicol. Ceftriaxone (87.5%) and Nitrofurantoin(72.3%) among other antibiotics was effective against Gram negative bacteria while all Enterobacteriaceae members were found to be resistant to tetracycline.


Author(s):  
Uma Chikkaraddi ◽  
Namratha W Nandihal

Coagulase Negative Staphylococci (CoNS) are common inhabitants of skin and mucous membrane, may act as pathogens causing fatal infections especially in immunocompromised patients. CoNS mainly cause infections involving biofilm on implanted biomaterials. Increase in antimicrobial resistance causes difficulties to treat life threatening infections. Despite their growing importance, their speciation is rarely done. Therefore, the present study is undertaken to identify CoNS to the species level and to know their antibiotic susceptibility pattern along with rate of MRCoNS.250 isolates from various clinical specimens were considered in this study. The isolates were identified by colony morphology, Gram staining, catalase, slide and tube coagulase test. Speciation was done by Novobiocin resistance, urease activity, ornithine decarboxylase, pyrrolidonylarylamidase and aerobic acid production from mannose. The antimicrobial susceptibility was performed by Kirby-Bauer's disc diffusion method as per CLSI guidelines.Among 250 CoNS isolates, commonest species identified was (59.2%) followed by (19.6%) and (12.4%). They were commonly isolated in the age group 21 to 30 years (26.8%) and among males(58%). Total of 33.2% were isolated from pus followed by blood(21.6%). Majority species expressed resistance towards nalidixic acid(97.2%) followed by Penicillin(94%), 74.4% to Amoxicillin-Clavulanic acid and 66.4% to Cotrimoxazole. All the isolates were sensitive to Vancomycin. Methicillin resistance among CoNS was 73.2%. : The increased recognition of pathogenic potential in CoNS and emergence of drug resistance among them demonstrates the need to adopt simple laboratory methods to identify the species and determine the antibiotic resistant patterns to help the clinicians in treating the infections caused by CoNS.


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