Detection of small colony variants among methicillin-resistant staphylococcus aureus blood isolates

Staphylococcus aureus small colony variants (SCVs) are associated with chronic and persistent infections. Methicillin-resistant S. aureus (MRSA) SCVs cause more severe infections and mortality rates are higher in comparison with infections caused by MRSA. Our objective was to document the prevalence and phenotypical characteristics of SCVs among MRSA blood isolates. MRSA strains isolated from blood during 1999-2009 were evaluated retrospectively. Among 299 MRSA isolates, suspected colonies were inoculated onto Columbia blood agar and Schaedler agar. Columbia blood agar was incubated in normal atmosphere and Schaedler agar in 5-10% CO2, both at 35°C. If the small, nonpigmented, nonhemolytic colonies on Columbia blood agar were seen as normal-sized, hemolytic, and pigmented colonies on Schaedler agar, they were considered as MRSA SCVs. Six MRSA SCVs were detected. When subcultures were made, four of them reversed to phenotypically normal S. aureus, but two isolates were stable as SCV phenotype. The prevalence of SCVs among MRSA blood isolates was found as 6/299 (2%) with 2 (0.67%) stable. The detection of SCVs among MRSA blood isolates was reported from Turkey for the first time in this study. As the clinical significance of MRSA infections is well documented, evaluation of MRSA SCVs in clinical samples, especially from intensive care patients and those who have chronic and persistent infections are important to consider. © Mary Ann Liebert, Inc. 2016

A comparison of PCR detection of <i> Meca</i> with oxacillin disk susceptibility testing in different media and sceptor automated system for both <i> Staphylococcus aureus</i> and coagulase-negative staphylococci isolates

Purpose: To evaluate three methods for 406 isolates of Staphylococcus aureus and coagulase-negative staphylococci (CNS) for the detection of methicillin resistance (MR) using National Committee for Clinical Laboratory Standards (NCCLS) new interpretive criteria. Methods: We used polymerase chain reaction (PCR) as a gold standard method to evaluate three methods [disk diffusion with Mueller-Hinton agar (MHA) and mannitol salt agar (MSA) and Sceptor system (Becton Dickinson, USA)] for the detection of mecA gene. The isolates that were methicillin-resistant with any of the three tests were evaluated further for MR by E-test. Results: MHA, MSA and Sceptor showed sensitivities of 100, 100 and 99 for S. aureus and 100, 82.6 and 72.1% for CNS, respectively. The specificities of the same methods were found as 100, 90.1 and 99.3% for S. aureus and 79.2, 95.8 and 97.2% for CNS, respectively. E-test showed 100 sensitivity for both S. aureus and CNS. Forty-eight CNS and 16 S. aureus isolates, which presented discrepancies with the three phenotypic methods (MHA disk diffusion method, MSA disk diffusion method and Sceptor), were correctly classified as resistant/susceptible with the E-test when compared with PCR. Only five CNS isolates, which were mecA-negative with PCR were resistant with E-test. Analysis of 248 S. aureus revealed that MHA is superior to other phenotype-based susceptibility testing methods in detecting MR. When we examined the results of 158 CNS, none of the three methods proved efficient in detecting MR. Conclusions: We conclude that although the accuracy of the MHA disk diffusion test for the detection of MR approaches the accuracy of PCR for S. aureus isolates, the need for easy and reliable methods of detecting MR in CNS still remains.WoSScopu

A comparison of PCR detection of Meca with oxacillin disk susceptibility testing in different media and sceptor automated system for both Staphylococcus aureus and coagulase-negative staphylococci isolates

Purpose: To evaluate three methods for 406 isolates of Staphylococcus aureus and coagulase-negative staphylococci (CNS) for the detection of methicillin resistance (MR) using National Committee for Clinical Laboratory Standards (NCCLS) new interpretive criteria. Methods: We used polymerase chain reaction (PCR) as a gold standard method to evaluate three methods [disk diffusion with Mueller-Hinton agar (MHA) and mannitol salt agar (MSA) and Sceptor system (Becton Dickinson, USA)] for the detection of mecA gene. The isolates that were methicillin-resistant with any of the three tests were evaluated further for MR by E-test. Results: MHA, MSA and Sceptor showed sensitivities of 100, 100 and 99% for S. aureus and 100, 82.6 and 72.1% for CNS, respectively. The specificities of the same methods were found as 100, 90.1 and 99.3% for S. aureus and 79.2, 95.8 and 97.2% for CNS, respectively. E-test showed 100% sensitivity for both S. aureus and CNS. Forty-eight CNS and 16 S. aureus isolates, which presented discrepancies with the three phenotypic methods (MHA disk diffusion method, MSA disk diffusion method and Sceptor), were correctly classified as resistant/susceptible with the E-test when compared with PCR. Only five CNS isolates, which were mecA-negative with PCR were resistant with E-test. Analysis of 248 S. aureus revealed that MHA is superior to other phenotype-based susceptibility testing methods in detecting MR. When we examined the results of 158 CNS, none of the three methods proved efficient in detecting MR. Conclusions: We conclude that although the accuracy of the MHA disk diffusion test for the detection of MR approaches the accuracy of PCR for S. aureus isolates, the need for easy and reliable methods of detecting MR in CNS still remains

Reversible Expression of Flagella in Campylobacter Spp.

The in vitro phase variation of flagella and the transition rates between flagellate and aflagellate phenotypes in Campylobacter species including C. jejuni, C. coli, C. lari (thermophilic campylobacters), C. fetus subsp. fetus, C. fetus subsp. venerealis and C. hyointestinalis were investigated. The change from the flagellate to aflagellate phenotype was detected in all of the 12 Campylobacter strains studied. When measured in a motility medium, flagellate to aflagellate transition in thermophilic campylobacters, C. fetus and C. hyointestinalis strains occurred at a rate of 1.8 × 10−3 to 7.5 × 10−3, 3.0 × 10−4 to 7.8 × 10−4 and 1.8 × 10−5 to 7.7 × 10−6 per cell per generation, respectively. Transition from aflagellate to flagellate phenotype occurred at a rate of 5.8 × 10−6 to 9.3 × 10−6 per cell per generation in thermophilic campylobacters and 1.0 × 10−6 to 1.5 × 10−6 in C. fetus strains. No reversion from aflagellate to flagellate phenotype could be detected in C. hyointestinalis strains. It was concluded that the ability to reversibly express flagella was inherent in the wild-type strains and the transition rates for both directions were consistent for each strain.Scopu

SYNTHESIS WORK ABOUT DRIVING MECHANISM OF A NOVEL ROTARY DOBBY MECHANISM

In this paper synthesis works of a dobby driving mechanism had been explained. Dobby experimental set has been constructed sum of three main parts; driving mechanism, program reading and locking unit; and mechanism for elevating motion to the frames. Sythesis work of driving mechanism is completed using analytical and mathematical approaches. Studied dobby construction is a unique fourteen framed rotary dobby mechanism, design works and experimental set building processes are carried out as part of a research project in a collaborative work of Suleyman Demirel University and Pamukkale University. The most important innovation is in the motion transmission mechanism on the main shaft of the rotational dobby. Main shaft is driven by oscilational motion with dwell period. Constructional analysis and synthesis works carried out during the mechanical designing period of the dobby driving mechanism is given in detail. Proposed dobby design can be considered to be manufactured and advised to be used on most of the standart weaving machines

SYNTHESIS WORK ABOUT DRIVING MECHANISM OF A NOVEL ROTARY DOBBY MECHANISM

In this paper synthesis works of a dobby driving mechanism had been explained. Dobby experimental set has been constructed sum of three main parts; driving mechanism, program reading and locking unit; and mechanism for elevating motion to the frames. Sythesis work of driving mechanism is completed using analytical and mathematical approaches. Studied dobby construction is a unique fourteen framed rotary dobby mechanism, design works and experimental set building processes are carried out as part of a research project in a collaborative work of Suleyman Demirel University and Pamukkale University. The most important innovation is in the motion transmission mechanism on the main shaft of the rotational dobby. Main shaft is driven by oscilational motion with dwell period. Constructional analysis and synthesis works carried out during the mechanical designing period of the dobby driving mechanism is given in detail. Proposed dobby design can be considered to be manufactured and advised to be used on most of the standart weaving machines

In Vitro Activities Of New Quinolones Against Brucella Melitensis Isolated In A Tertiary-Care Hospital In Turkey

We have evaluated the in vitro activities of seven fluoroquinolones against 69 strains of Brucella melitensis . According to their minimum inhibitory concentration for 90% growth (MIC90 ) values, the most active agent was found to be sparfloxacin (MIC90 0.12 mg/L) followed by levofloxacin, ciprofloxacin, ofloxacin (MIC90 0.50 mg/L) and grepafloxacin (MIC90 1 mg/L), gemifloxacin (MIC90 2 mg/L) and gatifloxacin (MIC90 4 mg/L).WoSScopu