Methicillin-Resistant Staphylococcus aureus: Clinical and Laboratory Features

1985 ◽  
Vol 6 (11) ◽  
pp. 461-465 ◽  
Author(s):  
Kenneth E. Aldridge

Not long after the introduction of penicillin G for anti-staphylococcal therapy, penicillin G resistant strains of staphylococci were isolated and were found to produce penicillinase enzymes. In 1959 methicillin, a penicillinase resistant penicillin (PRP), was introduced in England for therapy of these strains. Within 2 years the first strains of methicillin-resistant Staphylococcus aureus (MRSA) were reported in that country. Subsequently, reports of MRSA infections throughout Europe appeared. Reports from Switzerland and Denmark indicated that 30% to 50% of all nosocomial S. aureus isolates and 40% of all S. aureus bacteremia isolates, respectively, were due to MRSA. Although sporadic reports of MRSA infections appeared in the US after 1960 the first documented outbreak of MRSA infections occurred at Boston City Hospital in 1968. Even today there is not a complete understanding of MRSA and its role in infectious diseases, however, a vast amount of information has accumulated and certain aspects of this information will be discussed.

2014 ◽  
Vol 4 (7) ◽  
pp. 548-551 ◽  
Author(s):  
CP Bhatt ◽  
BMS Karki ◽  
B Baral ◽  
S Gautam ◽  
A Shah ◽  
...  

Background: Methicillin resistant Staphylococcus aureushas emerged as one of the most important nosocomial pathogens. It invokes a tremendous financial burden and enhanced morbidity and mortality due to difficult to treat systemic infections.Aim of this study was to determine antibiotic susceptibility pattern of Staphylococcus aureus and Methicillin resistant Staphylococcus aureus. Materials and Methods: Different clinical specimens were collected and processed for routine culture and antibiotic sensitivity test by standard microbiology techniques. Results: Out of 1173 samples received for microbiological examination, 100 were found to be S. aureus with 19% cases were Methicillin resistant Staphylococcus aureus (MRSA). Fourteen MRSA were found from inpatient and 5 were from outpatient. MRSA was found higher in female than male and maximum number (31.5%) was found in age group 0-10 years. Staphylococcus aureus was 100% sensitive to Vancomycin followed by Amikacin (90%), Gentamycin (83%), and tetracycline (81%). On urine isolates Nitrofurantoin(91.6%) was drug of choice. All the isolates were resistant to Penicillin G. In case of Methicillin resistant Staphylococcus aureus showed 100% sensitive to Vancomycin followed by Amikacin (84.2%), Tetracycline (63.1%), Ciprofloxacin (42%) and Gentamycin (36.8%). Among urine isolates Nitrofutantoin showed 87.5% sensitive followed by Norfloxacin (75%). Conclusion: Methicillin resistant Staphylococcus aureus was found 19% of Staphylococcus aureus isolates. It was most common in females, hospitalized patients and young age group. Vancomycin seems to be drug of choice followed by Amikacin. It would be helpful to formulating and monitoring the antibiotic policy and ensure proper empiric treatment. DOI: http://dx.doi.org/10.3126/jpn.v4i7.10297 Journal of Pathology of Nepal (2014) Vol. 4, 548-551   


2020 ◽  
Vol 27 (07) ◽  
pp. 1363-1370
Author(s):  
Aneela Khawaja ◽  
Iffat Javed ◽  
Sohaila Mushtaq ◽  
Saeed Anwar ◽  
Faiqa Arshad ◽  
...  

Antimicrobial resistance (AMR) is a devastating question that is threatening the health globally. The extensive and indiscriminative use of antibiotics has evolved a notorious resistance in Staphylococcus aureus.  This resistance developed through possession of mecA gene, which codes for modified penicillin binding protein (PBP2a) and the emergent strain being labeled “methicillin resistant Staphylococcus aureus”. Conventional phenotypic techniques for detection of MRSA rely on standardization of cultural characteristics. The drawbacks of diagnostic error to report MRSA include: poor prognosis, expensive treatment, dissemination of multi-drug resistant strains and even treatment failure. Latex agglutination method can be adopted as a more accurate and quick strategy for rapid detection of methicillin resistance. Objectives: To compare detection of mecA gene in methicillin resistant isolates of Staphylococcus aureus by latex agglutination and PCR; by assessing the sensitivity and specificity of both methods. Study Design: Descriptive Cross-Sectional study. Setting: Pathology Department, Post Graduate Medical Institute, Lahore. Period: From January 2015 to December 2015; according to standard operating procedures at Microbiology laboratory. Material & Methods: A total 713 consecutive, non-duplicate isolates of Staphylococcus aureus were processed. Methicillin resistance was determined using cefoxitin (30mg) by Kirby-Bauer method using CLSI guideline (2016), latex agglutination method; and PCR for mecA gene. Results: The results showed that out of 713 Staphylococcus aureus isolates, 92 (12.90%) isolates were resistant to cefoxitin and were labelled as MRSA. majority MRSA isolates recovered from pus (44.57%) and wound swab (20.65%), followed by blood (13.04%), fluid (8.70%), CSF (4.35%), CVP (3.26%), HVS (3.26%) and tracheal secretion (2.17%). By latex agglutination method, 87 (94.50%) were positive for PBP2a; while on PCR mecA gene was detected only in 82 (89.10%) MRSA isolates. When assessed with PCR (gold standard) the sensitivity and diagnostic accuracy of latex agglutination was 100% and 94.57%, respectively. Conclusion: Latex agglutination test can be employed as rapid and reliable diagnostic technique in MRSA isolates for mecA gene detection, where resources for molecular methods are inadequate. This can effectually lessen the misdiagnosis of resistant strains, and over/ ill-use of antibiotics.


2015 ◽  
Vol 26 (3) ◽  
pp. 233-243
Author(s):  
Kristine Anne Scordo

Methicillin-resistant Staphylococcus aureus (MRSA) continues to cause significant morbidity and mortality. Despite advances in medical care, the prevalence of both community-acquired and hospital-acquired MRSA has progressively increased. Community-acquired MRSA typically occurs in patients without recent illness or hospitalization, presents as acute skin and soft tissue infections, and is usually not multidrug resistant. Hospital-acquired MRSA, however, presents in patients recently hospitalized or treated in long-term care settings and in those who have had medical procedures and is usually associated with multidrug-resistant strains. Both types of infections, if not properly treated, have the potential to become invasive. This article discusses current intravenous antibiotics that are available for the empiric treatment of MRSA infections along with a newer phenomenon known as the “seesaw effect.”


2007 ◽  
Vol 70 (12) ◽  
pp. 2764-2768 ◽  
Author(s):  
DANIEL LOETO ◽  
M. I. MATSHEKA ◽  
B. A. GASHE

The prevalence, antibiotic resistance, and enterotoxigenic potential of Staphylococcus aureus strains from different anatomical sites on food handlers in Gaborone, Botswana, were determined. Of a total of 200 food handlers tested, 115 (57.5%) were positive for S. aureus. Of the 204 S. aureus isolates, 63 (30.9%), 91 (44.6%), and 50 (24.5%) were isolated from the hand, nasal cavity, and face, respectively, and 43 (21%) of the isolates were enterotoxigenic. The most prevalent enterotoxin was type A, which accounted for 34.9% of all the enterotoxigenic strains, and enterotoxin D was produced by the fewest number of strains (9.3%). Resistance to methicillin was encountered in 33 (22.4%) of the penicillin G–resistant isolates, and 9 (27.3%) of these methicillin-resistant isolates also were resistant to vancomycin. Nineteen antibiotic resistance profiles were determined, and the nasal cavity had the highest diversity of resistance profiles. The nasal cavity also had the highest number of resistant strains, 77 (53%), whereas the hand and face had 49 (32%) and 24 (16.0%) resistant strains, respectively. To reduce the Staphylococcus carriage rate among food handlers, training coupled with a commitment to high standards of personal and environmental hygiene is recommended.


2010 ◽  
Vol 27 (Special Issue 2) ◽  
pp. 36-41
Author(s):  
Z. Šťástková ◽  
S. Karpíšková ◽  
R. Karpíšková

The aim of our study was to determine the occurrence of methicillin resistant Staphylococcus aureus (MRSA) at dairy farms in the Czech Republic. Altogether 1061 samples from 95 farms were examined. The samples analysed were milk (individual and bulk tank milk samples), animal swabs and swabs from the farm environment. In total, 299 S. aureus isolates were obtained, of which 23 were MRSA. These MRSA isolates originated from three farms (13 isolates from farm A and 5 isolates from each of farms B and C). All MRSA isolates carried the mecA gene while none of them carried the genes for PVL, TSST-1 and exfoliatins. Only the isolates from goat farm C were positive for the genes encoding enterotoxins. By SCCmec typing, the strains were classified as community-associated MRSA carrying SCCmec IV or V. This study revealed that animals can be an important source of methicillin resistant staphylococci and represent a potential hazard of further spread.


2008 ◽  
Vol 52 (8) ◽  
pp. 2970-2973 ◽  
Author(s):  
Saichi Hoshi ◽  
Ken Kikuchi ◽  
Takashi Sasaki ◽  
Chie Sotozono ◽  
Shigeru Kinoshita ◽  
...  

ABSTRACT The bactericidal activities and postantibiotic effects (PAEs) of levofloxacin and gatifloxacin at concentrations corresponding to those in antibiotic eye drops against methicillin-resistant Staphylococcus aureus strains were determined. Levofloxacin and gatifloxacin at concentrations simulating those in eye drops showed lower bactericidal activities and shorter PAEs against fluoroquinolone-resistant strains than against fluoroquinolone-sensitive strains.


2000 ◽  
Vol 38 (1) ◽  
pp. 185-190
Author(s):  
Jacques-Olivier Galdbart ◽  
Anne Morvan ◽  
Nevine El Solh

ABSTRACT Methicillin-resistant strains susceptible to gentamicin (Gm s MRSA) have emerged since 1993 in several French hospitals. To study whether particular clones have spread in various French cities and whether some clones are related to gentamicin-resistant (Gm r ) MRSA strains, various methods (antibiotyping, phage typing, determination of Sma I macrorestriction patterns before and after hybridization with IS 256 transposase and aacA-aphD probes) were used to compare 62 Gm s MRSA strains isolated from 1995 to 1997 in nine cities and 15 Gm r MRSA strains. Eighteen major Sma I genotypes were identified, of which 11 included only Gm s MRSA strains and 5 included only Gm r MRSA strains. Each of the Gm r MRSA strains contained 6 to 13 Sma I fragments hybridizing with the insertion sequence IS 256 , of which a single band also hybridized with the aacA-aphD gene. No such hybridizing sequences were detected in 60 of the 62 Gm s MRSA strains. Thus, the divergence between Gm r and Gm s MRSA strains is revealed, not only by their distributions in distinct Sma I genotypes but also by the differences in hybridization patterns. Two of the 62 Gm s MRSA strains had the uncommon feature of carrying several Sma I bands hybridizing with IS 256 , suggesting that they are possibly related to the Gm r MRSA strains grouped in the same Sma I genotype. Five of the 11 Sma I genotypes including only Gm s MRSA strains contained strains from diverse cities, isolated during different years and with different antibiograms, suggesting that some clones have spread beyond their cities of origin and persisted.


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