scholarly journals Research on the Phenotypic Characterization of Mrsa Strains Isolated from Animals

2017 ◽  
Vol 74 (1) ◽  
pp. 88
Author(s):  
Iulia Maria BUCUR ◽  
Viorel HERMAN ◽  
Corina PASCU ◽  
Ionita IANCU ◽  
Janos DEGI ◽  
...  
Keyword(s):  
Methicillin Resistance ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Phenotypic Characterization ◽  
Diffusion Test ◽  
Chromogenic Medium ◽  
Disk Diffusion Test ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
Mrsa Strains

Keywords: chromogen, methicillin, MRSA, resistanceIntroduction: Currently, both in staphylococci isolated from animals with different diseases, as well as in humans, the MRSA strains (Methicillin Resistant S. aureus) are monitored, as the methicillin resistance is associated with the resistance to other antibiotic groups.Methicillin resistance is encoded by mec staphylococcal chromosomal cassettes (SCCmec), which are islands of resistance. These strains can be identified by molecular biology tests and tests that reveal several phenotypic characteristics.The research was made in order to characterize and identify phenotypically the MRSA staphylococci strains isolated from animals.Materials and Methods: Researches were made on 240 coagulase positive and coagulase negative strains of staphylococci. Mannitol fermentation was tested on Champan medium, free coagulase was revealed on Baird-Parker medium and to identify S. aureus subsp. aureus was used the chromogenic medium Chromatic Staph.Methicillin-resistant strains were detected by disc diffusion method, using biodiscs with methicillin, oxacillin and cefoxitin. Also, to identify the MRSA strains, was used the chromogenic medium Chromatic MRSA.Results: The isolates were positive to mannitol and produced complete haemolysis or were unhaemolytic. A total of 44 strains produced free coagulase on Baird-Parker medium, considered coagulase positive strains, while 196 were coagulase negative strains.The isolates conducted differently to methicillin: 22,08% of strains were resistant, 51,25% of strains were susceptible and 26,66% had intermediate resistance, while the resistant strains to oxacillin were 42,91%.The increased frequency of methicillin-resistant strains of staphylococci and, particularly, MRSA strains, determined using the cefoxitin disk diffusion test, which is more reliable than methicillin and oxacillin.On the MRSA chromogenic medium, the methicillin-resistant strains of staphylococci formed colonies with pigment from mauve to orange mauve.Conclusion: The obtained results by disk diffusion test on resistance patterns to 3 beta-lactams, resistant to penicillinase, indicated a different frequency of the resistant strains to these antibiotics.Cefoxitin disk diffusion test revealed a frequency of 2,51% of resistant strains, that can be considered MRSA strains.

scholarly journals Ceftaroline resistance in Staphylococcus pseudintermedius gene mecA carriers

2018 ◽  
Vol 38 (12) ◽  
pp. 2233-2236
Author(s):  
Carolina B. Scherer ◽  
Larissa S. Botoni ◽  
Antônio U. Carvalho ◽  
Kelly M. Keller ◽  
Adriane P. Costa-Val
Keyword(s):  
Methicillin Resistance ◽  
Meca Gene ◽  
Disk Diffusion ◽  
Diffusion Test ◽  
Staphylococcus Pseudintermedius ◽  
Ceftaroline Fosamil ◽  
Disk Diffusion Test ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
Current Report

ABSTRACT: Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) being a constant concern, ceftaroline fosamil has been recently approved as a new cephalosporin, active against MRSA, for use in humans; only rare cases of resistance have been reported till date. There is no report of resistance to ceftaroline in Staphylococcus pseudintermedius, which is the main bacterium causing dermatitis and otitis in dogs. To evaluate staphylococcal resistance to ceftaroline, 35 isolates of methicillin-resistant S. pseudintermedius (MRSP), carrying the mecA gene, from 26 dogs with folliculitis and nine dogs with external otitis, underwent disk diffusion test with cefoxitin, oxacillin, and ceftaroline. Tests with cefoxitin and oxacillin showed > 90% sensitivity in methicillin resistance detection. In the disk diffusion test, 97.14% (34/35) were resistant to cefoxitin, 94.29% (33/35) to oxacillin, and 31.43% (11/35) to ceftaroline. Of the ceftaroline-resistant strains, 27.27% (3/11) were obtained from the ears of dogs while the rest (8/11) were from the skin. The current report is the first description of MRSP resistance to ceftaroline.

Staphylococci isolated from animals and food with phenotypically reduced susceptibility to β-lactamase-resistant β-lactam antibiotics

2004 ◽  
Vol 52 (1) ◽  
pp. 7-17 ◽  
Author(s):  
Éva J. Kaszanyitzky ◽  
Zsuzsanna Egyed ◽  
Sz. Jánosi ◽  
Judit Keserű ◽  
Zsuzsanna Gál ◽  
...  
Keyword(s):  
Inhibition Zone ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Resistance Pattern ◽  
Coagulase Negative Staphylococci ◽  
Disk Diffusion Method ◽  
Disk Diffusion Test ◽  
Methicillin Resistant ◽  
Zone Diameter ◽  
Mrsa Strains

The antibiotic resistance pattern of 1921 Staphylococcus strains isolated from animals and food within the last two years were examined using diffusion tests. Among them there were only 35 strains of S. aureus having an inhibition zone diameter of 15 mm or less, and 4 strains of coagulase-negative staphylococci (CNS) having a zone diameter of 18 mm or less to 1-µg oxacillin disk. These 39 strains were examined also by E-test to oxacillin and for the detection of the mecA gene by PCR in order to determine whether they might be real methicillin-resistant staphylococci. Among the 39 strains there were only two that were susceptible to penicillin by disk diffusion method; however, further examination by the penicillinase test showed that they produced ß-lactamase. While 19 (15 S. aureus, 4 CNS) strains were resistant and 7 strains were intermediate to oxacillin in disk diffusion test, the E-test gave 8 resistant and 5 intermediate results. Six out of the 8 oxacillin-resistant strains examined by disk diffusion and E-test harboured the mecA gene. Thus only 6 out of the examined 1921 strains proved to be mecA positive. These methicillin-resistant, mecA-positive strains (5 of the S. aureus strains and 1 of the S. epidermidis) originated from two dairy herds. The results prove that methicillin-resistant S. aureus (MRSA) strains in animals are really rare in Hungary. Eighteen strains were chosen and screened for minimal inhibitory concentration (MIC) of oxacillin with or without clavulanic acid or sulbactam, and three of them produced methicillinase enzyme.

scholarly journals Peculiarities of antibiotic resistance of Staphylococcus aureus strains isolated from nosocomial infections

2020 ◽  
Vol 101 (3) ◽  
pp. 325-329
Author(s):  
S A Atakishizade
Keyword(s):  
Antibiotic Resistance ◽  
Nosocomial Infections ◽  
Methicillin Resistance ◽  
Surgical Site Infections ◽  
Diffusion Method ◽  
Methicillin Resistant ◽  
Inducible Clindamycin Resistance ◽  
Significant Difference ◽  
Microbiological Testing ◽  
Mrsa Strains

Aim. To study of the antibiotic resistance of S. aureus strains isolated from nosocomial infections (pneumonia, surgical site infections and sepsis) in a multidisciplinary surgical clinic. Methods. Microbiological testing of sputum in 41 patients with pneumonia, of samples (wound, abscess, drainage) obtained from 40 patients with surgical site infections (SSI) and of blood from 46 patients with signs of sepsis was performed. The obtaining cultures were identified by conventional methods (including morphological, cultural, biochemical features, etc.). Disc diffusion method was used to detect methicillin-resistant S. aureus (MRSA) strains. Inducible clindamycin resistance (ICR) of S. aureus strains was determined by double disk approximation test (D-test). Results. Methicillin-resistant S. aureus was found in 14.3% (2 of 14) of the patients with surgical site infections, in the sputum 27.3% (3 of 11) of the patients with pneumonia, and in the blood 50.0% (7 of 14) of the patients with sepsis (p 0.05). The rate of inducible clindamycin resistance of isolated S. aureus strains in patients with surgical site infections (2 of 14 cases, 14.3%) and with pneumonia (2 of 11 cases, 18.2%) did not statistically significant difference with the rate of methicillin resistance (p 0.05). However the rate was significantly lower septic infections 7.1% and 50.0% respectively (p=0.0328). Conclusion. Among S. aureus strains isolated from nosocomial infections, the rate of methicillin-resistant S. aureus had not depended on the type of nosocomial infection; the rate of inducible clindamycin resistance in septic infections was lower than resistance to methicillin.

scholarly journals Evaluation of Screening and Commercial Methods for Detection of Methicillin Resistance in Coagulase-Negative Staphylococci

1998 ◽  
Vol 36 (1) ◽  
pp. 273-274 ◽  
Author(s):  
Zafar Hussain ◽  
Luba Stoakes ◽  
Robert Lannigan ◽  
Susan Longo ◽  
Barbara Nancekivell
Keyword(s):  
Clinical Laboratory ◽  
Methicillin Resistance ◽  
Disk Diffusion ◽  
National Committee ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
Time To Detection ◽  
Combination Of Methods ◽  
The Times

The National Committee for Clinical Laboratory Standards recommends 48 h of incubation by the oxacillin salt agar screen (OSAS) method for the detection of methicillin-resistant coagulase-negative staphylococci (CoNS). An earlier identification of methicillin resistance is desirable. The time to detection of the mecAgene by PCR was compared with the times to detection by OSAS, by the oxacillin disk diffusion (ODD) method, and with MicroScan Gram Positive Combo type 6 panels (MicroScan Inc. Sacramento, Calif.) and Vitek GPS-SA cards (bioMérieux Vitek Inc., Hazelwood, Mo.). The combination of the Vitek card and the ODD method detected 92 of 99 methicillin-resistant strains of CoNS at 24 h; however, 6mecA-positive strains were phenotypically methicillin susceptible. We conclude that most methicillin-resistant CoNS can be detected and the results can be reported after overnight incubation by a combination of methods.

Incidence and antibiotic susceptibility of methicillin resistant Staphylococcus aureus in pus samples of patients of Bastar region, Central India

2012 ◽  
Vol 2 (5) ◽  
pp. 204-208
Author(s):  
Mohammad Fareed Khan ◽  
Arvind Neral ◽  
Vikas Chandra Yadav ◽  
Farah Aziz Khan ◽  
Sarfaraz Ahmed
Keyword(s):  
Antibiotic Susceptibility ◽  
Tertiary Care ◽  
Central India ◽  
Empirical Therapy ◽  
Disk Diffusion ◽  
Antibiotic Prescribing ◽  
Care Hospital ◽  
Diffusion Test ◽  
Disk Diffusion Test ◽  
Methicillin Resistant

Increasing prevalence of methicillin resistant S. aureus (MRSA) and resistanceto multiple antibiotic classes is a global issue. Regional surveillance of antibiotic susceptibility of the organism is a necessary step to overcome the issues of antimicrobial resistance and treatment failure in MRSA infections. The study was conducted to find the pattern of antibiotic susceptibility in MRSA isolated from the pus samples of patients attending a tertiary care hospital in Bastar tribal region in Central India. The study was performed on 215 MRSA isolates cultured from pus samples of patients over a period of two years and five months. In the methicillin resistant organisms selected by oxacillin screen agar test and cefoxitin disk diffusion test, antibiotic susceptibility was determined by Kirby Baur disk diffusion test with CLSI guide lines. Of the total S. aureus isolates, the incidence of MRSA was 34.1% of which 82.8% were resistant to co‐trimoxazole, 77.2% to tetracycline, 68.8% to gentamycin, 66% to erythromycin, 64.2% to ciprofloxacin, 1.4% to vancomycin, and 0.9% to linezolid. All these isolates were resistant to the ß‐lactam antibiotics tested. Emergence of linezolid resistance and relatively higher vancomycin resistance in the MRSA isolates is a worrisome finding of this study. The antibiotic prescribing must rely on both initial empirical therapy and microbiological antibiotic susceptibility result.

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