Simple and economical method for identification and speciation of Staphylococcus epidermidis and other coagulase negative Staphylococci and its validation by molecular methods

2018 ◽  
Vol 149 ◽  
pp. 106-119 ◽  
Author(s):  
Suresh Sah ◽  
Priyanka Bordoloi ◽  
D. Vijaya ◽  
Satish Kumar Amarnath ◽  
C. Sheela Devi ◽  
...  
Author(s):  
Zeynep Güngördü Dalar ◽  
Güzin İskeleli ◽  
Mert Ahmet Kuşkucu ◽  
Mehmet Demirci ◽  
Penbe Çağatay ◽  
...  

Objective: The most important bacteria of the conjunctival microbiota are Staphylococcus epidermidis, diphteroid rods, Corynebacterium spp. and Cutibacterium acnes. Especially biofilm formation of S. epidermidis is very important for contact lens related infections. For this purpose, we aimed to examine the changes in the presence of biofilm-forming S. epidermidis and other coagulase-negative staphylococci in conjunctival swabs taken before and after lens usage in 140 patients (90 hydrogel, 50 silicone hydrogel) who were prepared to wear lenses. Methods: Coagulase-negative staphylococci isolated from the conjunctival microbiota identified standard clinical microbiological methods, after identification of S.epidermidis strains with API Staph; Slime production was determined by Congo red agar, standard tube and molecular methods. Results: S.epidermidis was the most frequently isolated species in conjunctival microbiota before and after lens usage. Before lens usage, slime positive S. epidermidis strains were found as 45-50% but after lens usage it was 59% in hydrogel contact lens users and 70.2% in silicone hydrogel contact lens users. For the investigation of slime production, 82 (50.9%) of 161 S. epidermidis strains were found positive by using Congo red agar, 61 (37.8%) by standard tube method and 91 (56.5%) by molecular methods. Conclusion: The result of our study suggests that there are no significant changes in bacterial ratios before and after lens use, but bacteria such as S. epidermidis can predispose to infections by using slime production and contact lens factor. Also; molecular methods and Congo Red Agar method were found to be more reliable than the Standard Tube method.


2010 ◽  
Vol 54 (11) ◽  
pp. 4684-4693 ◽  
Author(s):  
George G. Zhanel ◽  
Melanie DeCorby ◽  
Heather Adam ◽  
Michael R. Mulvey ◽  
Melissa McCracken ◽  
...  

ABSTRACT A total of 5,282 bacterial isolates obtained between 1 January and 31 December 31 2008, inclusive, from patients in 10 hospitals across Canada as part of the Canadian Ward Surveillance Study (CANWARD 2008) underwent susceptibility testing. The 10 most common organisms, representing 78.8% of all clinical specimens, were as follows: Escherichia coli (21.4%), methicillin-susceptible Staphylococcus aureus (MSSA; 13.9%), Streptococcus pneumoniae (10.3%), Pseudomonas aeruginosa (7.1%), Klebsiella pneumoniae (6.0%), coagulase-negative staphylococci/Staphylococcus epidermidis (5.4%), methicillin-resistant S. aureus (MRSA; 5.1%), Haemophilus influenzae (4.1%), Enterococcus spp. (3.3%), Enterobacter cloacae (2.2%). MRSA comprised 27.0% (272/1,007) of all S. aureus isolates (genotypically, 68.8% of MRSA were health care associated [HA-MRSA] and 27.6% were community associated [CA-MRSA]). Extended-spectrum β-lactamase (ESBL)-producing E. coli occurred in 4.9% of E. coli isolates. The CTX-M type was the predominant ESBL, with CTX-M-15 the most prevalent genotype. MRSA demonstrated no resistance to ceftobiprole, daptomycin, linezolid, telavancin, tigecycline, or vancomycin (0.4% intermediate intermediate resistance). E. coli demonstrated no resistance to ertapenem, meropenem, or tigecycline. Resistance rates with P. aeruginosa were as follows: colistin (polymyxin E), 0.8%; amikacin, 3.5%; cefepime, 7.2%; gentamicin, 12.3%; fluoroquinolones, 19.0 to 24.1%; meropenem, 5.6%; piperacillin-tazobactam, 8.0%. A multidrug-resistant (MDR) phenotype occurred frequently in P. aeruginosa (5.9%) but uncommonly in E. coli (1.2%) and K. pneumoniae (0.9%). In conclusion, E. coli, S. aureus (MSSA and MRSA), P. aeruginosa, S. pneumoniae, K. pneumoniae, H. influenzae, and Enterococcus spp. are the most common isolates recovered from clinical specimens in Canadian hospitals. The prevalence of MRSA was 27.0% (of which genotypically 27.6% were CA-MRSA), while ESBL-producing E. coli occurred in 4.9% of isolates. An MDR phenotype was common in P. aeruginosa.


2004 ◽  
Vol 132 (5) ◽  
pp. 921-925 ◽  
Author(s):  
M. MÜLLER-PREMRU ◽  
P. ČERNELČ

Catheter-related bloodstream infection (CRBSI) caused by coagulase-negative staphylococci (CNS) is common in haematological patients with febrile neutropenia. As the clinical signs of CRBSI are usually scarce and it is difficult to differentiate from blood culture contamination, we tried to confirm CRBSI by molecular typing of CNS isolated from paired blood cultures (one from a peripheral vein and another from the central venous catheter hub). Blood cultures were positive in 59 (36%) out of 163 patients. CNS were isolated in 24 (40%) patients; in 14 from paired blood cultures (28 isolates) and in 10 from a single blood culture. CNS from paired blood cultures were identified as Staphylococcus epidermidis. Antimicrobial susceptibility was determined and bacteria were typed by pulsed-field gel electrophoresis (PFGE) of bacterial genomic DNA. In 13 patients, the antibiotic susceptibility of isolates was identical. The PFGE patterns from paired blood cultures were identical or closely related in 10 patients, thus confirming the presence of CRBSI. In the remaining four patients they were unrelated, and suggested a mixed infection or contamination. Since CNS isolates from three patients had identical PFGE patterns, they were probably nosocomially spread amongst them.


2017 ◽  
Vol 62 (2) ◽  
Author(s):  
Jana Basas ◽  
Marta Palau ◽  
Carlos Ratia ◽  
José L. del Pozo ◽  
María Teresa Martín-Gómez ◽  
...  

ABSTRACT Long-term catheter-related bloodstream infections (CRBSIs) involving coagulase-negative staphylococci are associated with poor patient outcomes, increased hospitalization, and high treatment costs. The use of vancomycin lock therapy has been an important step forward in treatment of these biofilms, although failures occur in 20% of patients. In this study, we report that a high dose of daptomycin lock therapy may offer a therapeutic advantage for these CRBSIs in just 24 h of treatment.


2012 ◽  
Vol 61 (8) ◽  
pp. 1136-1145 ◽  
Author(s):  
Ana Maria Nunes Botelho ◽  
Zilma das Graça Nunes ◽  
Marise Dutra Asensi ◽  
Marisa Zenaide Ribeiro Gomes ◽  
Sérgio Eduardo Longo Fracalanzza ◽  
...  

2019 ◽  
Vol 57 (12) ◽  
Author(s):  
C. Paul Morris ◽  
Patricia J. Simner

ABSTRACT Accurate detection of methicillin resistance among staphylococci is vital for patient care. Methicillin resistance is most commonly mediated by acquisition of the mecA gene, which encodes an altered penicillin binding protein, PBP2a. Application of phenotypic methods to detect mecA-mediated beta-lactam resistance in staphylococci is becoming more complex as species-specific differences are identified among coagulase-negative staphylococci (CoNS). Previously, interpretative criteria and antimicrobial susceptibility testing (AST) methods specific to the CoNS group were used to evaluate Staphylococcus epidermidis. A manuscript by S. N. Naccache, K. Callan, C.-A. D. Burnham, M. A. Wallace, et al. (J Clin Microbiol 57:e00961-19, 2019, https://doi.org/10.1128/JCM.00961-19) details experiments revealing that S. epidermidis, the most common clinically isolated CoNS, requires tailored use of previously described methods and interpretive criteria to reliably identify the presence of mecA-mediated methicillin resistance.


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