scholarly journals Identification of biochemically atypical Staphylococcus aureus clinical isolates with three automated identification systems

2006 ◽  
Vol 55 (4) ◽  
pp. 387-392 ◽  
Author(s):  
Yoshikazu Ishii ◽  
Jimena Alba ◽  
Chikako Maehara ◽  
Hinako Murakami ◽  
Tetsuya Matsumoto ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pcr Analysis ◽  
Automatic Identification ◽  
Automated Identification ◽  
Becton Dickinson ◽  
Mannitol Salt Agar ◽  
Confidence Levels ◽  
Fully Automatic ◽  
Automated Identification Systems ◽  
Produce Acid

Between January and April 2002, a total of 271 strains of Staphylococcus aureus were isolated from clinical specimens at Toho University Omori Hospital, Japan, including 201 (74·2 %) which were identified as meticillin-resistant S. aureus (MRSA). However, 34 (12·5 %) were biochemically atypical, because they did not produce acid on mannitol salt agar or did not agglutinate in Staphaurex testing but were categorized as MRSA by PCR analysis and by antibiotic susceptibility. Three automatic identification systems, AutoScan-4® (Dade Behring), BD Phoenix™ (Becton Dickinson) and Vitek® 2 (bioMérieux), were evaluated by testing these atypical S. aureus isolates. The AutoScan-4® and Phoenix™ systems identified all 34 isolates as S. aureus. Without additional tests such as Staphaurex, observation of colony pigment and haemolysins on sheep blood agar, Vitek® 2 identified only 16 isolates (47·1 %) as S. aureus with good or better confidence levels and misidentified one of the remaining isolates as Staphylococcus chromogenes. This study shows that it is possible to identify these physiologically atypical S. aureus isolates correctly by using the Phoenix™ and AutoScan-4® fully automatic identification systems.

Staphylococcus aureus Nasal Carriage in Medical Students of Universiti Teknologi MARA

2017 ◽  
Vol 2 (1) ◽  
pp. 29 ◽  
Author(s):  
Zaini Mohd Zain ◽  
Muhammad Fikri Johari ◽  
Nurul Shahirah Mohd Husin ◽  
Nurul Syamimi Rozman ◽  
Athirah Ab Rashid ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Medical Students ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Nasal Carriage ◽  
Tissue Necrosis ◽  
Mannitol Salt Agar ◽  
Microbiological Techniques ◽  
Polymerase Chain ◽  
Low Prevalence ◽  
Panton Valentine Leukocidin

Introduction: To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage and detection of S. aureus leukotoxins among medical students of Universiti Teknologi MARA. Methods: Both sides of the anterior nares of 136 volunteers, comprising 68 preclinical and 68 clinical medical students, were swabbed and immediately cultured onto mannitol salt agar for growth of S. aureus. Standard microbiological techniques were conducted to identify and confirm the S. aureus colonies and susceptibility test against oxacillin were conducted by using Kirby-Bauer method to determine their resistance to methicillin. Polymerase chain reaction was performed for detection of leukotoxins, i.e., Panton-Valentine Leukocidin (PVL) and -haemolysin genes. Results: Nineteen students (14%) consisting of 10 preclinical (14.7%) and 9 clinical (13.2%) were nasal carriers of S. aureus. However, none of the S. aureus isolates were MRSA. No PVL gene was detected but eight of them were positive for -haemolysin gene. Conclusion: There were no MRSA nasal carriers among the medical students, but a low prevalence of S. aureus nasal carriers was detected. These carriers do not pose as high risk because none of the strains of S. aureus possess both the -haemolysin toxin and the PVL toxin that are associated with tissue necrosis.

scholarly journals Detection of Methicillin Resistant Staphylococcus aureus in Dairy Products and Anterior Nares of Dairy Workers

2019 ◽  
Vol 6 ◽  
pp. 59-62
Author(s):  
Ranjana K.C. ◽  
Ganga Timilsina ◽  
Anjana Singh ◽  
Supriya Sharma
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Susceptibility ◽  
Dairy Products ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Dairy Product ◽  
Control Measures ◽  
Diffusion Method ◽  
Mannitol Salt Agar ◽  
Methicillin Resistant ◽  
Dairy Workers

Objectives: To isolate methicillin resistant Staphylococcus aureus (MRSA) from anterior nares of dairy workers and dairy products and assess the antibiotic susceptibility pattern of the isolates. Methods: Swab samples collected from anterior nares of dairy workers and dairy product (butter) were inoculated into mannitol salt agar and incubated at 37ºC for 24 hours. Identification was done based on colony characteristics, Gram's staining, catalase, oxidase and coagulase test. Antibiotic susceptibility testing was done by modified Kirby Bauer disc diffusion method. MRSA was confirmed by using cefoxitin disc. Results: A total of 109 S. aureus (98 from dairy workers and 11 from butter samples) were isolated. Out of them 32 MRSA were isolated from dairy workers and 4 from butter samples. The association between age group and MRSA was found insignificant (p = 0.115). The association of MRSA between male and female workers was found significant (>0.05). About 86% of the MRSA isolates were susceptible to Gentamicin (86.11%) followed by Ciprofloxacin (77.78%). Conclusion: Detection of MRSA among dairy workers and dairy products warrants proper handling and adequate control measures to prevent transmission of MRSA from dairy industry.

scholarly journals Antagonism between Aminoglycosides and β-Lactams in a Methicillin-Resistant Staphylococcus aureus Isolate Involves Induction of an Aminoglycoside-Modifying Enzyme

2002 ◽  
Vol 46 (5) ◽  
pp. 1516-1521 ◽  
Author(s):  
Takashi Ida ◽  
Ryoichi Okamoto ◽  
Masato Nonoyama ◽  
Kazuhiko Irinoda ◽  
Mizuyo Kurazono ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Antimicrobial Activities ◽  
Hybrid Structure ◽  
Conjugative Plasmid ◽  
Pcr Analysis ◽  
Aminoglycoside Resistance ◽  
Gene Encoding ◽  
Methicillin Resistant ◽  
Aureus Isolate

ABSTRACT We encountered three clinical isolates of methicillin-resistant Staphylococcus aureus which were susceptible to netilmicin and arbekacin in the absence of β-lactam antibiotics but which were resistant to them in the presence of β-lactam antibiotics. One of these strains, KU5801, was used to further investigate the antagonism between aminoglycosides and β-lactam antibiotics. β-Lactam antibiotics induced bacterial synthesis of aminoglycoside-6′-N-acetyltransferase and 2"-O-phosphotransferase [AAC(6′)-APH(2")] in association with decreased antimicrobial activities of aminoglycosides. A 14.4-kb EcoRI fragment that included the genes that control for β-lactam-inducible aminoglycoside resistance was cloned from a 31-kb conjugative plasmid present in KU5801. Restriction fragment mapping and PCR analysis suggested that a Tn4001-like element containing a gene encoding AAC(6′)-APH(2") was located downstream from a truncated blaZ gene. The DNA sequence between blaR1 and a Tn4001-like element was determined. The Tn4001-IS257 hybrid structure was cointegrated into the blaZ gene, and the typical sequences for the termination of transcription were not found between these regions. We deduced that antagonism of aminoglycosides by β-lactam antibiotics in isolate KU5801 involved transcription of the aac(6′)-Ie-aph(2")-Ia gene under the influence of the system regulating penicillinase production.

scholarly journals Case Study: Misdiagnosis of Nonhemolytic Staphylococcus aureus Isolates from Cases of Bovine Mastitis as Coagulase-Negative Staphylococci

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 252
Author(s):  
Valerie E. Ryman ◽  
Felicia M. Kautz ◽  
Steve C. Nickerson
Keyword(s):  
Staphylococcus Aureus ◽  
Bovine Mastitis ◽  
Dairy Farm ◽  
Blood Agar ◽  
Coagulase Negative Staphylococci ◽  
Mannitol Salt Agar ◽  
Lactating Cows ◽  
Presumptive Identification ◽  
Microbiological Techniques

Staphylococcus aureus is one of the most concerning mastitis-causing pathogens in dairy cattle. Using basic microbiological techniques, S. aureus is typically identified by colony characteristics and hemolysis on blood agar where isolates without hemolysis are typically considered to be coagulase-negative staphylococci (CNS) isolates. Herein, we present a decade-long case study where suspected S. aureus isolates from one Georgia dairy farm were further tested to confirm presumptive identification. Presumptive identification of bacterial growth from 222 mammary secretions from bred Holstein heifers and lactating cows was conducted at the time of collection. Presumptive identification of S. aureus on blood agar was based on observation of colony morphology, color, and presence or absence of a broad zone of incomplete hemolysis and a smaller zone of complete hemolysis at 48 h. Those without hemolysis were presumptively characterized as CNS. All isolates were further plated on mannitol salt agar and a coagulase test was performed. A positive for both of these tests together was deemed to be S. aureus. A selection of isolates was tested using API® Staph to biochemically confirm S. aureus identification. Data showed that 63.96% of isolates presumed to be CNS isolates were identified as S. aureus, 9.46% of isolates presumed to be CNS isolates were identified as coagulase-positive staphylococci (CPS) species (but not S. aureus), and 26.58% of samples that were presumed to be CNS isolates were identified correctly.

scholarly journals Analogs of Eap Protein Are Conserved and Prevalent in Clinical Staphylococcus aureus Isolates

2001 ◽  
Vol 8 (6) ◽  
pp. 1271-1276 ◽  
Author(s):  
Muzaffar Hussain ◽  
Karsten Becker ◽  
Christof von Eiff ◽  
Georg Peters ◽  
Mathias Herrmann
Keyword(s):  
Staphylococcus Aureus ◽  
Extracellular Matrix ◽  
Staphylococcus Epidermidis ◽  
Translation Termination ◽  
Pcr Analysis ◽  
Cloning And Sequencing ◽  
Extracellular Matrix Molecules ◽  
Size Variability ◽  
Early Translation ◽  
High Degree

ABSTRACT Map and Eap are secreted Staphylococcus aureus proteins that interact with various extracellular matrix molecules. PCR analysis using map primers yielded positive reactions in 97.9% of S. aureus isolates but not in Staphylococcus epidermidis isolates. Cloning and sequencing of the conferring genes revealed a high degree of overall homology combined with size variability of the gene product due to various repeat numbers and early translation termination in a poly(A) region. Thus, Map and Eap may provide a potential novel tool forS. aureus identification and typing.

scholarly journals A NEW FULLY-AUTOMATIC PROCEDURE FOR THE IDENTIFICATION AND THE COUPLING OF THE OVERTOPPING WAVES

2018 ◽  
pp. 36 ◽  
Author(s):  
Sara Mizar Formentin ◽  
Barbara Zanuttigh
Keyword(s):  
Flow Velocity ◽  
Water Surface ◽  
Automatic Identification ◽  
Practical Relevance ◽  
Threshold Values ◽  
Flow Conditions ◽  
Fully Automatic ◽  
The Individual ◽  
Coupling Algorithm ◽  
Submerged Conditions

This contribution presents a new procedure for the automatic identification of the individual overtopping events. The procedure is based on a zero-down-crossing analysis of the water-surface-elevation signals and, based on two threshold values, can be applied to any structure crest level, i.e. to emerged, zero-freeboard, over-washed and submerged conditions. The results of the procedure are characterized by a level of accuracy comparable to the human-supervised analysis of the wave signals. The procedure includes a second algorithm for the coupling of the overtopping events registered at two consecutive gauges. This coupling algorithm offers a series of original applications of practical relevance, a.o. the possibility to estimate the wave celerities, i.e. the velocities of propagation of the single waves, which could be used as an approximation of the flow velocity in shallow water and broken flow conditions.

scholarly journals Prevalence of Methicillin-Resistant Staphylococcus aureus on Paper Currency Notes

2021 ◽  
pp. 25-32
Author(s):  
Rikhi Ram Marasini ◽  
Pratikshya Shrestha ◽  
Prabhat Dhakal ◽  
Sukra Raj Shrestha ◽  
Sirjana Adhikari ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Brain Heart Infusion ◽  
Biochemical Tests ◽  
Mannitol Salt Agar ◽  
Methicillin Resistant ◽  
Total Prevalence ◽  
Paper Currency ◽  
Antibiotic Susceptibility Test ◽  
Hygiene Measures

The main objective of this study was to determine the prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) in paper currency. The paper currencies in circulation in Pokhara Metropolitan City were inspected. Bills of various denominations (Rs 5, 10, 20, 50, 100, 500 and 1000) were collected from five different locations; namely Food and Vegetable Shop, Bus conductor, Hospital Pharmacy, Butcher Shop and Grocery Shop. Collected sample were cultured and incubated for 24 hours at 37 oC in Brain Heart Infusion (BHI) Broth. The inoculums were further cultured on Mannitol Salt Agar (MSA) and Blood Agar (BA) media to obtain colonies, which were examined and evaluated for various parameters like gram staining and biochemical tests for identification. Then, antibiotic susceptibility test of the isolates was performed using standard procedures. A total of 35 sample of paper currency were processed, all of which showed positive growth. Out of 86 total isolates, 21 (24.42%) were Staphylococcus aureus followed by Coagulase Negative Staphylococci 19 (22.09%), Diptheroids 14 (16.3%), Bacillus spp 13 (15.11%), Micrococci 9 (10.46%), Streptococcus pneumonia 4 (4.65%), Viridans Streptococcus 4 (4.65%) and Streptococcus pyogenes 2 (2.32%). The total prevalence of MRSA in this study was 7 (33.33%). Paper currency contaminated with MRSA poses a high threat to those handling the bills as well as the community. Thus, this study suggests proper hygiene measures to be adopted after handling of paper currency to minimize the risk of contamination and emergence of diseases.

scholarly journals Evaluation of Mannitol Salt Agar for Detection of Oxacillin Resistance in Staphylococcus aureus by Disk Diffusion and Agar Screening

1998 ◽  
Vol 36 (8) ◽  
pp. 2254-2257 ◽  
Author(s):  
Günter Kampf ◽  
Christoph Lecke ◽  
Ann-Katrin Cimbal ◽  
Klaus Weist ◽  
Henning Rüden
Keyword(s):  
Staphylococcus Aureus ◽  
Disk Diffusion ◽  
Diffusion Test ◽  
Mannitol Salt Agar ◽  
Disk Diffusion Test ◽  
Zone Diameter ◽  
Oxacillin Resistance

Mannitol salt agar was evaluated for detection of oxacillin resistance in 136 Staphylococcus aureus isolates. AllmecA-positive isolates (n = 54) were correctly categorized as oxacillin resistant by the disk diffusion test (1-μg disk; zone diameter, <16 mm); the specificity was 97.6%. Agar screening (2 μg of oxacillin per ml) revealed a sensitivity of 98.1% and a specificity of 95.1%.

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